The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial comp...The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial composition in subgingival plaque suggest that nitrate-reducing bacteria are associated with periodontal health, but the impact of periodontitis on nitrate-reducing capacity(NRC)and, therefore, nitric oxide availability has not been evaluated. The current study aimed to evaluate how periodontitis affects the NRC of the oral microbiota. First, 16S rRNA sequencing data from five different countries were analyzed, revealing that nitratereducing bacteria were significantly lower in subgingival plaque of periodontitis patients compared with healthy individuals(P < 0.05 in all five datasets with n = 20–82 samples per dataset). Secondly, subgingival plaque, saliva, and plasma samples were obtained from 42 periodontitis patients before and after periodontal treatment. The oral NRC was determined in vitro by incubating saliva with 8 mmol/L nitrate(a concentration found in saliva after nitrate-rich vegetable intake) and compared with the NRC of 15healthy individuals. Salivary NRC was found to be diminished in periodontal patients before treatment(P < 0.05) but recovered to healthy levels 90 days post-treatment. Additionally, the subgingival levels of nitrate-reducing bacteria increased after treatment and correlated negatively with periodontitis-associated bacteria(P < 0.01). No significant effect of periodontal treatment on the baseline saliva and plasma nitrate and nitrite levels was found, indicating that differences in the NRC may only be revealed after nitrate intake. Our results suggest that an impaired NRC in periodontitis could limit dietary nitrate-derived nitric oxide levels, and the effect on systemic health should be explored in future studies.展开更多
Plant diseases and pests present significant challenges to global food security, leading to substantial losses in agricultural productivity and threatening environmental sustainability. As the world’s population grow...Plant diseases and pests present significant challenges to global food security, leading to substantial losses in agricultural productivity and threatening environmental sustainability. As the world’s population grows, ensuring food availability becomes increasingly urgent. This review explores the significance of advanced plant disease detection techniques in disease and pest management for enhancing food security. Traditional plant disease detection methods often rely on visual inspection and are time-consuming and subjective. This leads to delayed interventions and ineffective control measures. However, recent advancements in remote sensing, imaging technologies, and molecular diagnostics offer powerful tools for early and precise disease detection. Big data analytics and machine learning play pivotal roles in analyzing vast and complex datasets, thus accurately identifying plant diseases and predicting disease occurrence and severity. We explore how prompt interventions employing advanced techniques enable more efficient disease control and concurrently minimize the environmental impact of conventional disease and pest management practices. Furthermore, we analyze and make future recommendations to improve the precision and sensitivity of current advanced detection techniques. We propose incorporating eco-evolutionary theories into research to enhance the understanding of pathogen spread in future climates and mitigate the risk of disease outbreaks. We highlight the need for a science-policy interface that works closely with scientists, policymakers, and relevant intergovernmental organizations to ensure coordination and collaboration among them, ultimately developing effective disease monitoring and management strategies needed for securing sustainable food production and environmental well-being.展开更多
AIM: To investigate the effect of high homocysteine(Hcy) levels on apolipoprotein E(apoE) expression and the signaling pathways involved in this gene regulation.METHODS: Reverse transcriptase polymerase chain reaction...AIM: To investigate the effect of high homocysteine(Hcy) levels on apolipoprotein E(apoE) expression and the signaling pathways involved in this gene regulation.METHODS: Reverse transcriptase polymerase chain reaction(RT-PCR) and Western blot were used to assess apo E expression in cells treated with various concentrations(50-500 μmol/L) of Hcy. Calcium phosphatetransient transfections were performed in HEK-293 and RAW 264.7 cells to evaluate the effect of Hcy on apoE regulatory elements [promoter and distal multienhancer 2(ME2)]. To this aim, plasmids containing the proximal apoE promoter [(-500/+73)apoE construct] alone or in the presence of ME2 [ME2/(-500/+73)apoE construct] to drive the expression of the reporter luciferase gene were used. Co-transfection experiments were carried out to investigate the downstream effectors of Hcymediated regulation of apoE promoter by using specific inhibitors or a dominant negative form of IKβ. In other co-transfections, the luciferase reporter was under the control of synthetic promoters containing multiple specific binding sites for nuclear factor kappa B(NF-κB), activator protein-1(AP-1) or nuclear factor of activated T cells(NFAT). Chromatin immunoprecipitation(ChI P)assay was accomplished to detect the binding of NF-κB p65 subunit to the apoE promoter in HEK-293 treated with 500 μmol/L Hcy. As control, cells were incubated with similar concentration of cysteine. NF-κB p65 proteins bound to DNA were immunoprecipitated with anti-p65 antibodies and DNA was identified by PCR using primers amplifying the region-100/+4 of the apoE gene. RESULTS: RT-PCR revealed that high levels of Hcy(250-750 μmol/L) induced a 2-3 fold decrease in apoE m RNA levels in HEK-293 cells, while apo E gene expression was not significantly affected by treatment with lower concentrations of Hcy(100 μmol/L). Immunoblotting data provided additional evidence for the negative role of Hcy in apoE expression. Hcy decreased apoE promoter activity, in the presence or absence of ME2, in a dose dependent manner, in both RAW 264.7 and HEK-293 cells, as revealed by transient transfection experiments. The downstream effectors of the signaling pathways of Hcy were also investigated. The inhibitory effect of Hcy on the apo E promoter activity was counteracted by MAPK/ERK kinase 1/2(MEK1/2) inhibitor U0126, suggesting that MEK1/2 is involved in the downregulation of apoE promoter activity by Hcy. Our data demonstrated that Hcy-induced inhibition of apoE took place through activation of NF-κB. Moreover, we demonstrated that Hcy activated a synthetic promoter containing three NF-κB binding sites, but did not affect promoters containing AP-1 or NFAT binding sites. ChI P experiments revealed that NF-κB p65 subunit is recruited to the apoE promoter following Hcy treatment of cells.CONCLUSION: Hcy-induced stress negatively modulates apoE expression via MEK1/2 and NF-κB activation. The decreased apo E expression in peripheral tissues may aggravate atherosclerosis, neurodegenerative diseases and renal dysfunctions.展开更多
Texture is a complex trait and a major component of fruit quality in apple.While the major effect of MdPG1,a gene controlling firmness,has already been exploited in elite cultivars,the genetic basis of crispness remai...Texture is a complex trait and a major component of fruit quality in apple.While the major effect of MdPG1,a gene controlling firmness,has already been exploited in elite cultivars,the genetic basis of crispness remains poorly understood.To further improve fruit texture,harnessing loci with minor effects via genomic selection is therefore necessary.In this study,we measured acoustic and mechanical features in 537 genotypes to dissect the firmness and crispness components of fruit texture.Predictions of across-year phenotypic values for these components were calculated using a model calibrated with 8,294 SNP markers.The best prediction accuracies following cross-validations within the training set of 259 genotypes were obtained for the acoustic linear distance(0.64).Predictions for biparental families using the entire training set varied from low to high accuracy,depending on the family considered.While adding siblings or half-siblings into the training set did not clearly improve predictions,we performed an optimization of the training set size and composition for each validation set.This allowed us to increase prediction accuracies by 0.17 on average,with a maximal accuracy of 0.81 when predicting firmness in the‘Gala’בPink Lady’family.Our results therefore identified key genetic parameters to consider when deploying genomic selection for texture in apple.In particular,we advise to rely on a large training population,with high phenotypic variability from which a‘tailored training population’can be extracted using a priori information on genetic relatedness,in order to predict a specific target population.展开更多
A few EST-derived STS markers localized on Qfhs.ndsu-3BS, a major QTL for resistance to Fusarium head blight （FHB） in wheat, have been previously identified in the ＇Sumai 3＇/＇Stoa＇ population. In this study, we ...A few EST-derived STS markers localized on Qfhs.ndsu-3BS, a major QTL for resistance to Fusarium head blight （FHB） in wheat, have been previously identified in the ＇Sumai 3＇/＇Stoa＇ population. In this study, we used a ＇Wangshuibai＇ （resistant）/＇Seri82＇ （susceptible） derived population, linkage group, QTL, and quantitative gene expression analysis to assess the genetic background dependence and stability of the EST-derived STS markers for use in marker aided selection to improve FHB resistance in wheat. Based on our results, a QTL in the map interval of Xsts3B-138_1-Xgwrn493 on chromosome 3BS was detected for FHB resistance, which accounted for up to 16% of the phenotypic variation. BLASTN analysis indicated that Xsts3B-138_1 sequence had significant similarity with the resistance gene analogue. Real-time quantitative PCR showed that the relative expression of Xsts3B-138_1 in ＇Wangshuibai＇ at 96 h after inoculation was 2.6 times higher than ＇Seri82＇. Our results underlined that EST-derived STS3B-138 markers could be predominantly used in marker aided selection to improve FHB resistance in wheat.展开更多
The application of population genetic methods in combination with gene mapping strategies can help to identify genes and mutations selected during the evolution from wild plants to crops and to explore the considerabl...The application of population genetic methods in combination with gene mapping strategies can help to identify genes and mutations selected during the evolution from wild plants to crops and to explore the considerable genetic variation still maintained in natural populations.We genotyped a grapevine germplasm collection of 44 wild(Vitis vinifera subsp.sylvestris)and 48 cultivated(V.vinifera subsp.sativa)accessions at 54 K single-nucleotide polymorphisms(SNPs)to perform a whole-genome comparison of the main population genetic statistics.The analysis of Wright Fixation Index(FST)along the whole genome allowed us to identify several putative“signatures of selection”spanning over two thousand SNPs significantly differentiated between sativa and sylvestris.Many of these genomic regions included genes involved in the adaptation to environmental changes.An overall reduction of nucleotide diversity was observed across the whole genome within sylvestris,supporting a small effective population size of the wild grapevine.Tajima’s D resulted positive in both wild and cultivated subgroups,which may indicate an ongoing balancing selection.Association mapping for six domestication-related traits was performed in combination with population genetics,providing further evidence of different perception and response to environmental stresses between sativa and sylvestris.展开更多
To decipher the transcriptomic regulation of the on-tree fruit maturation in pear cv.‘Abate Fetel’,a RNA-seq transcription analysis identified 8939 genes differentially expressed across four harvesting stages.These ...To decipher the transcriptomic regulation of the on-tree fruit maturation in pear cv.‘Abate Fetel’,a RNA-seq transcription analysis identified 8939 genes differentially expressed across four harvesting stages.These genes were grouped into 11 SOTA clusters based on their transcriptional pattern,of which three included genes upregulated while the other four were represented by downregulated genes.Fruit ripening was furthermore investigated after 1 month of postharvest cold storage.The most important variation in fruit firmness,production of ethylene and volatile organic compounds were observed after 5 days of shelf-life at room temperature following cold storage.The role of ethylene in controlling the ripening of‘Abate Fetel’pears was furthermore investigated through the application of 1-methylcyclopropene,which efficiently delayed the progression of ripening by reducing fruit softening and repressing both ethylene and volatile production.The physiological response of the interference at the ethylene receptor level was moreover unraveled investigating the expression pattern of 12 candidate genes,initially selected to validate the RNA-seq profile.This analysis confirmed the effective role of the ethylene competitor in downregulating the expression of cell wall(PG)and ethylene-related genes(ACS,ACO,ERS1,and ERS2),as well as inducing one element involved in the auxin signaling pathway(Aux/IAA),highlighting a possible cross-talk between these two hormones.The expression patterns of these six elements suggest their use as molecular toolkit to monitor at molecular level the progression of the fruit on-tree maturation and postharvest ripening.展开更多
To elucidate the physiology underlying the development of superficial scald in pears,susceptible“Blanquilla”fruit was treated with different compounds that either promoted(ethylene)or repressed(1-methylcyclopropene ...To elucidate the physiology underlying the development of superficial scald in pears,susceptible“Blanquilla”fruit was treated with different compounds that either promoted(ethylene)or repressed(1-methylcyclopropene and lovastatin)the incidence of this disorder after 4 months of cold storage.Our data show that scald was negligible for the fruit treated with 1-methylcyclopropene or lovastatin,but highly manifested in untreated(78%incidence)or ethylenetreated fruit(97%incidence).The comparison between the fruit metabolomic profile and transcriptome evidenced a distinct reprogramming associated with each treatment.In all treated samples,cold storage led to an activation of a cold-acclimation-resistance mechanism,including the biosynthesis of very-long-chain fatty acids,which was especially evident in 1-methylcyclopropane-treated fruit.Among the treatments applied,only 1-methylcyclopropene inhibited ethylene production,hence supporting the involvement of this hormone in the development of scald.However,a common repression effect on the PPO gene combined with higher sorbitol content was found for both lovastatin and 1-methylcyclopropene-treated samples,suggesting also a non-ethylene-mediated process preventing the development of this disorder.The results presented in this work represent a step forward to better understand the physiological mechanisms governing the etiology of superficial scald in pears.展开更多
Rice genes OsDjA2 and OsERF104,encoding a chaperone protein and an APETELA2/ethylene-responsive factor,respectively,are strongly induced in a compatible interaction with blast fungus,and also have function in plant su...Rice genes OsDjA2 and OsERF104,encoding a chaperone protein and an APETELA2/ethylene-responsive factor,respectively,are strongly induced in a compatible interaction with blast fungus,and also have function in plant susceptibility validated through gene silencing.Here,we reported the CRISPR/Cas9 knockout of OsDjA2 and OsERF104 genes resulting in considerable improvement of blast resistance.A total of 15 OsDjA2(62.5%)and 17 OsERF104(70.8%)T_(0)transformed lines were identified from 24 regenerated plants for each target and used in downstream experiments.Phenotyping of homozygous T1 mutant lines revealed not only a significant decrease in the number of blast lesions but also a reduction in the percentage of diseased leaf area,compared with the infected control plants.Our results supported CRISPR/Cas9-mediated target mutation in rice susceptibility genes as a potential and alternative breeding strategy for building resistance to blast disease.展开更多
Genetic diversity evaluation of mutant lines is essential to facilitate their conservation and utility in breeding programs. Characterization of plant genotypes using morphological markers has limitations which make t...Genetic diversity evaluation of mutant lines is essential to facilitate their conservation and utility in breeding programs. Characterization of plant genotypes using morphological markers has limitations which make the procedure inefficient. Application of molecular tools for characterization and diversity assessment has been found useful to complement phenotypic evaluation of plant population. Therefore genetic diversity of some cowpea mutant lines was studied using simple sequence repeats (SSR) markers. DNA barcoding marker, ribulose-1,5-bisphosphate carboxylase(rbcL) of the chloroplast DNA (cpDNA) was also used for characterization and identification of the mutants to species level. The mean polymorphic information content (0.51) obtained from the microsatellites showed high polymorphism in accessing wide genetic diversity among the mutants and their parents. Dendrogram generated revealed 8 groups with most mutants clustered separately from their parents. Sequence analysis revealed insertions/deletions (InDels) and base substitutions as the two main classes of mutations induced in the plastid DNA of the mutants studied. The nucleotide frequencies were 26.95% (A), 34.43% (T), 24.09% (C) and 14.53% (G). A total of 61.38% AT rich region was identified, while GC rich region was found to be 38.62%. Highest rate of mutations were observed in region 3 - 4 indicating that the region is less conserved in cowpea rbcL gene. The present study proved that SSR markers are useful for the genetic diversity assessment of cowpea mutants. It also proved the efficiency of rbcL markers in mutants’ identification. The results indicate that the mutants are valuable genetic resources that have been developed to widen cowpea genetic base.展开更多
Malus x domestica microRNA MdmiR285N is a potential key regulator of plant immunity,as it has been predicted to target 35 RNA transcripts coding for different disease resistance proteins involved in plant defense to p...Malus x domestica microRNA MdmiR285N is a potential key regulator of plant immunity,as it has been predicted to target 35 RNA transcripts coding for different disease resistance proteins involved in plant defense to pathogens.In this study,the promoter region of MdmiR285N was isolated from the apple genome and analyzed in silico to detect potential regulatory regions controlling its transcription.A complex network of putative regulatory elements involved in plant growth and development,and in response to different hormones and stress conditions,was identified.Activity of theβ-Glucoronidase(GUS)reporter gene driven by the promoter of MdmiR285N was examined in transgenic apple,demonstrating that MdmiR285N was expressed during the vegetative growth phase.Similarly,in transgenic Arabidopsis thaliana,spatial and temporal patterns of GUS expression revealed that MdmiR285N was differentially regulated during seed germination,vegetative phase change,and reproductive development.To elucidate the role of MdmiR285N in plant immunity,MdmiR285N expression in wild-type apple plants and GUS activity in transgenic apple and Arabidopsis thaliana plants were monitored in response to Erwinia amylovora and Pseudomonas syringae pv.Tomato DC3000.A significant decrease of MdmiR285N levels and GUS expression was observed during host-pathogen infections.Overall,these data suggest that MdmiR285N is involved in the biotic stress response,plant growth,and reproductive development.展开更多
One of the major causes of congenital hypophosphatemic rickets is the X-linked hypophosphatemic rickets (XHR), due to a defect on PHEX gene. The XHR increases the renal elimination of phosphate, that condition leads a...One of the major causes of congenital hypophosphatemic rickets is the X-linked hypophosphatemic rickets (XHR), due to a defect on PHEX gene. The XHR increases the renal elimination of phosphate, that condition leads a defective mineralization of bones and also affects the growth in children. Clinical diagnosis should be suspected in children with signs of rickets and hypophosphatemia with normal calcium levels. We describe clinical characteristics and genetic results of four patients diagnosed and treated in our Nephrology Section. All patients have a “de novo” XHR as none familiars are affected. Early diagnosis should be suspected before the bone deformities have been submitted and the growth would have been impaired.展开更多
We hypothesize that individuals with genetic predisposition to Substance Use Disorder (SUD) may have greater likelihood of experiencing work related accidents. We further hypothesize that high risk populations will ca...We hypothesize that individuals with genetic predisposition to Substance Use Disorder (SUD) may have greater likelihood of experiencing work related accidents. We further hypothesize that high risk populations will carry single or multiple polymorphisms associated with brain reward circuitry and/or brain reward cascade, including: Dopaminergic (i.e. DRD2 receptor genes);Serotonergic (i.e. 5-HTT2 receptor genes);Endorphinergic (i.e. pre-enkephalin genes);Gabergic (i.e. GABAA receptor genes);Neurotransmitter Metabolizing genes (i.e. MAO and COMT genes) among others (GARSRXTM). Analgesic addiction as well as “pseudoaddiction” must be treated to improve pain control and its management. We propose that non-pharmacological alternatives to pain relief, in high risk, addiction-prone individuals, are Electrotherapeutic Device(s) and Programs. We further propose patented KB220Z, a nutraceutical designed to release dopamine at the nucleus accumbens, will reduce craving behavior, in genetically programmed individuals. By utilizing both alternatives in DNA analyzed injured workers, a reduction in analgesic addiction (genuine or pseudo) leads to improved health and quicker return to work. We also hypothesize that this novel approach will impact costs related to injuries in the workforce. Effective management of chronic pain, especially in high addiction-prone workforce populations, is possible in spite of being particularly elusive. A series of factors encumber pain assessment and management, including analgesia addiction, pharmacogenomic response to pain medications, and genetically inherited factors involving gene polymorphisms. Additional research is required to test these stipulated hypotheses related to genetic proneness to addiction, but also proneness to accidents in the workplace and reduction of craving behavior. Our hypothesis that genotyping coupled with both KB220ZTM and the pharmaceutical-free Electrotherapy, will reduce iatrogenic induced analgesia addiction. This approach will achieve attainable effective pain management and quicker return to work. We propose outcomes such as the Reward Deficiency System SolutionTM may become an adjunct in the war against iatrogenic pain medication addiction.展开更多
The objective of this paper is to present a new ideotype of grain legume cultivar and show improvements in breeding from the introduction of the terminal inflorescence （ti） gene in field bean, and the introduction o...The objective of this paper is to present a new ideotype of grain legume cultivar and show improvements in breeding from the introduction of the terminal inflorescence （ti） gene in field bean, and the introduction of the restricted branching （rb） gene in three lupin crops--narrow-leafed lupin, white lupin and yellow lupin. Field trials using control cultivars were conducted at the Research Center for Cultivar Testing in Poland. For each species, different trial periods were selected in which new cultivars with ti/rb genes were registered. A breeding progress was estimated by a comparison of a new cultivar to control--bridge cultivar to the next trial period. Over the past twenty years cultivar improvement using ti/rb genes has proceeded differently in these species. The newest, self-completing legume cultivars have yields comparable to traditional ones and generally are earlier and more uniform when mature. This paper shows that breeding progress in rb yellow lupin is outstanding; in rb narrow-leafed lupin and ti field bean is favorable; and in rb white lupin is moderate.展开更多
In 2010,a major scientific milestone was achieved for tree fruit crops:publication of the first draft whole genome sequence(WGS)for apple(Malus domestica).This WGS,v1.0,was valuable as the initial reference for sequen...In 2010,a major scientific milestone was achieved for tree fruit crops:publication of the first draft whole genome sequence(WGS)for apple(Malus domestica).This WGS,v1.0,was valuable as the initial reference for sequence information,fine mapping,gene discovery,variant discovery,and tool development.A new,high quality apple WGS,GDDH13 v1.1,was released in 2017 and now serves as the reference genome for apple.Over the past decade,these apple WGSs have had an enormous impact on our understanding of apple biological functioning,trait physiology and inheritance,leading to practical applications for improving this highly valued crop.Causal gene identities for phenotypes of fundamental and practical interest can today be discovered much more rapidly.Genome-wide polymorphisms at high genetic resolution are screened efficiently over hundreds to thousands of individuals with new insights into genetic relationships and pedigrees.High-density genetic maps are constructed efficiently and quantitative trait loci for valuable traits are readily associated with positional candidate genes and/or converted into diagnostic tests for breeders.We understand the species,geographical,and genomic origins of domesticated apple more precisely,as well as its relationship to wild relatives.The WGS has turbo-charged application of these classical research steps to crop improvement and drives innovative methods to achieve more durable,environmentally sound,productive,and consumer-desirable apple production.This review includes examples of basic and practical breakthroughs and challenges in using the apple WGSs.Recommendations for“what’s next”focus on necessary upgrades to the genome sequence data pool,as well as for use of the data,to reach new frontiers in genomics-based scientific understanding of apple.展开更多
Morphological variation of snails from the genus Trochulus is so huge that their taxonomy is unclear. The greatest variability concerns forms hispidus and sericeus/plebeius, which are often considered as separate spec...Morphological variation of snails from the genus Trochulus is so huge that their taxonomy is unclear. The greatest variability concerns forms hispidus and sericeus/plebeius, which are often considered as separate species. To evidence the species barriers, we carried out crossbreeding ex- periments between these two sympatric morphs. Moreover, we compared the shell morphology of laboratory-bred offspring with their wild parents to test if the variation can be explained by the phenotypic plasticity model. We found that the two Trochulus morphs show no reproductive bar- riers. The fecundity rates, the mean clutch size, and F~ viability observed for all crosses were not significantly different. In hybrid crosses （in F2 generation）, we also recorded reproduction compati- bility, similar fecundity, and hatching success as in their parents. Accordingly, phylogenetic ana- lyses revealed the significant grouping of sequences from these different morphs and supported no constrains in reproduction between them. Comparison of shell morphology between wild and laboratory samples showed that various characters appeared highly plastic. The average shell shape of the hispidus morph changed significantly from flat with wide umbilicus to elevated with narrower umbilicus such as in the sericeus/plebeius morph. All these findings indicate that the examined morphs do not represent separate biological species and the evolutionary process is not advanced enough to separate their genetic pool. Therefore, phenotypic plasticity has played a sig- nificant role in the evolution of Trochulus shell polymorphism. The two morphs can evolve inde- pendently in separate phylogenetic lineages under the influence of local environmental conditions.展开更多
Despite most COVID-19 infections being asymptomatic,China's Mainland had a high increase in symptomatic cases at the end of 2022.In this study,we examine China's sudden COVID-19 symptomatic surge using a conce...Despite most COVID-19 infections being asymptomatic,China's Mainland had a high increase in symptomatic cases at the end of 2022.In this study,we examine China's sudden COVID-19 symptomatic surge using a conceptual SIR-based model.Our model considers the epidemiological characteristics of SARS-CoV-2,particularly variolation,from non-pharmaceutical intervention(facial masking and social distance),demography,and disease mortality in China's Mainland.The increase in symptomatic proportions in China may be attributable to(1)higher sensitivity and vulnerability during winter and(2)enhanced viral inhalation due to spikes in SARS-CoV-2 infections(high transmissibility).These two reasons could explain China's high symptomatic proportion of COVID-19 in December 2022.Our study,therefore,can serve as a decision-support tool to enhance SARS-CoV-2 prevention and control efforts.Thus,we highlight that facemask-induced variolation could potentially reduces transmissibility rather than severity in infected individuals.However,further investigation is required to understand the variolation effect on disease severity.展开更多
In late March 2020,SARS-CoV-2 arrived in Manaus,Brazil,and rapidly developed into a large-scale epidemic that collapsed the local health system and resulted in extreme death rates.Several key studies reported that∼76...In late March 2020,SARS-CoV-2 arrived in Manaus,Brazil,and rapidly developed into a large-scale epidemic that collapsed the local health system and resulted in extreme death rates.Several key studies reported that∼76%of residents of Manaus were infected(attack rate AR≃76%)by October 2020,suggesting protective herd immunity had been reached.Despite this,an unexpected second wave of COVID-19 struck again in November and proved to be larger than the first,creating a catastrophe for the unprepared population.It has been suggested that this could be possible if the second wave was driven by reinfections.However,it is widely reported that reinfections were at a low rate(before the emergence of Omicron),and reinfections tend to be mild.Here,we use novel methods to model the epidemic from mortality data without considering reinfection-caused deaths and evaluate the impact of interventions to explain why the second wave appeared.The method fits a“flexible”reproductive numberR_(0)(t)that changes over the epidemic,and it is demonstrated that the method can successfully reconstruct R_(0)(t)from simulated data.For Manaus,the method finds AR≃34%by October 2020 for the first wave,which is far less than required for herd immunity yet in-line with seroprevalence estimates.The work is complemented by a two-strain model.Using genomic data,the model estimates transmissibility of the new P.1 virus lineage as 1.9 times higher than that of the non-P.1.Moreover,an age class model variant that considers the high mortality rates of older adults show very similar results.These models thus provide a reasonable explanation for the two-wave dynamics in Manaus without the need to rely on large reinfection rates,which until now have only been found in negligible to moderate numbers in recent surveillance efforts.展开更多
基金funded by grants from EU Marie Curie ITN RAPID(grant number 290246)Versus Arthritis(Grant Number 20823)+4 种基金the BBSRC(BB/P504567/1)supported by a student stipend from the University of Glasgow and Dentsply Sirona(Project Number 300881)supported by a grant from the European Regional Development Fund and the Spanish Ministry of Science,Innovation and Universities with the reference RTI2018-102032-B-I00the Valencian Innovation Agency with the reference INNVAL20/19/006supported by an FPI fellowship from the Spanish Ministry of Science,Innovation,and Universities with the reference Bio2015-68711-R。
文摘The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial composition in subgingival plaque suggest that nitrate-reducing bacteria are associated with periodontal health, but the impact of periodontitis on nitrate-reducing capacity(NRC)and, therefore, nitric oxide availability has not been evaluated. The current study aimed to evaluate how periodontitis affects the NRC of the oral microbiota. First, 16S rRNA sequencing data from five different countries were analyzed, revealing that nitratereducing bacteria were significantly lower in subgingival plaque of periodontitis patients compared with healthy individuals(P < 0.05 in all five datasets with n = 20–82 samples per dataset). Secondly, subgingival plaque, saliva, and plasma samples were obtained from 42 periodontitis patients before and after periodontal treatment. The oral NRC was determined in vitro by incubating saliva with 8 mmol/L nitrate(a concentration found in saliva after nitrate-rich vegetable intake) and compared with the NRC of 15healthy individuals. Salivary NRC was found to be diminished in periodontal patients before treatment(P < 0.05) but recovered to healthy levels 90 days post-treatment. Additionally, the subgingival levels of nitrate-reducing bacteria increased after treatment and correlated negatively with periodontitis-associated bacteria(P < 0.01). No significant effect of periodontal treatment on the baseline saliva and plasma nitrate and nitrite levels was found, indicating that differences in the NRC may only be revealed after nitrate intake. Our results suggest that an impaired NRC in periodontitis could limit dietary nitrate-derived nitric oxide levels, and the effect on systemic health should be explored in future studies.
文摘Plant diseases and pests present significant challenges to global food security, leading to substantial losses in agricultural productivity and threatening environmental sustainability. As the world’s population grows, ensuring food availability becomes increasingly urgent. This review explores the significance of advanced plant disease detection techniques in disease and pest management for enhancing food security. Traditional plant disease detection methods often rely on visual inspection and are time-consuming and subjective. This leads to delayed interventions and ineffective control measures. However, recent advancements in remote sensing, imaging technologies, and molecular diagnostics offer powerful tools for early and precise disease detection. Big data analytics and machine learning play pivotal roles in analyzing vast and complex datasets, thus accurately identifying plant diseases and predicting disease occurrence and severity. We explore how prompt interventions employing advanced techniques enable more efficient disease control and concurrently minimize the environmental impact of conventional disease and pest management practices. Furthermore, we analyze and make future recommendations to improve the precision and sensitivity of current advanced detection techniques. We propose incorporating eco-evolutionary theories into research to enhance the understanding of pathogen spread in future climates and mitigate the risk of disease outbreaks. We highlight the need for a science-policy interface that works closely with scientists, policymakers, and relevant intergovernmental organizations to ensure coordination and collaboration among them, ultimately developing effective disease monitoring and management strategies needed for securing sustainable food production and environmental well-being.
基金Supported by The grant of the Romanian National Authority for Scientific Research,National Research Council-Executive Agency for Higher Education,Research,Development and Innovation Funding,No.PN-II-ID-PCE-2011-3-0591(grant awarded to Gafencu AV)the Romanian Academy,and the strategic grant financed by the European Social Found within the Sectorial Operational Program Human Resources Development 2007-2013,No.POSDRU/159/1.5/S/133391(Fenyo IM and Trusca VG)
文摘AIM: To investigate the effect of high homocysteine(Hcy) levels on apolipoprotein E(apoE) expression and the signaling pathways involved in this gene regulation.METHODS: Reverse transcriptase polymerase chain reaction(RT-PCR) and Western blot were used to assess apo E expression in cells treated with various concentrations(50-500 μmol/L) of Hcy. Calcium phosphatetransient transfections were performed in HEK-293 and RAW 264.7 cells to evaluate the effect of Hcy on apoE regulatory elements [promoter and distal multienhancer 2(ME2)]. To this aim, plasmids containing the proximal apoE promoter [(-500/+73)apoE construct] alone or in the presence of ME2 [ME2/(-500/+73)apoE construct] to drive the expression of the reporter luciferase gene were used. Co-transfection experiments were carried out to investigate the downstream effectors of Hcymediated regulation of apoE promoter by using specific inhibitors or a dominant negative form of IKβ. In other co-transfections, the luciferase reporter was under the control of synthetic promoters containing multiple specific binding sites for nuclear factor kappa B(NF-κB), activator protein-1(AP-1) or nuclear factor of activated T cells(NFAT). Chromatin immunoprecipitation(ChI P)assay was accomplished to detect the binding of NF-κB p65 subunit to the apoE promoter in HEK-293 treated with 500 μmol/L Hcy. As control, cells were incubated with similar concentration of cysteine. NF-κB p65 proteins bound to DNA were immunoprecipitated with anti-p65 antibodies and DNA was identified by PCR using primers amplifying the region-100/+4 of the apoE gene. RESULTS: RT-PCR revealed that high levels of Hcy(250-750 μmol/L) induced a 2-3 fold decrease in apoE m RNA levels in HEK-293 cells, while apo E gene expression was not significantly affected by treatment with lower concentrations of Hcy(100 μmol/L). Immunoblotting data provided additional evidence for the negative role of Hcy in apoE expression. Hcy decreased apoE promoter activity, in the presence or absence of ME2, in a dose dependent manner, in both RAW 264.7 and HEK-293 cells, as revealed by transient transfection experiments. The downstream effectors of the signaling pathways of Hcy were also investigated. The inhibitory effect of Hcy on the apo E promoter activity was counteracted by MAPK/ERK kinase 1/2(MEK1/2) inhibitor U0126, suggesting that MEK1/2 is involved in the downregulation of apoE promoter activity by Hcy. Our data demonstrated that Hcy-induced inhibition of apoE took place through activation of NF-κB. Moreover, we demonstrated that Hcy activated a synthetic promoter containing three NF-κB binding sites, but did not affect promoters containing AP-1 or NFAT binding sites. ChI P experiments revealed that NF-κB p65 subunit is recruited to the apoE promoter following Hcy treatment of cells.CONCLUSION: Hcy-induced stress negatively modulates apoE expression via MEK1/2 and NF-κB activation. The decreased apo E expression in peripheral tissues may aggravate atherosclerosis, neurodegenerative diseases and renal dysfunctions.
基金funded by the EU seventh Framework Programme by the FruitBreedomics Project No.265582。
文摘Texture is a complex trait and a major component of fruit quality in apple.While the major effect of MdPG1,a gene controlling firmness,has already been exploited in elite cultivars,the genetic basis of crispness remains poorly understood.To further improve fruit texture,harnessing loci with minor effects via genomic selection is therefore necessary.In this study,we measured acoustic and mechanical features in 537 genotypes to dissect the firmness and crispness components of fruit texture.Predictions of across-year phenotypic values for these components were calculated using a model calibrated with 8,294 SNP markers.The best prediction accuracies following cross-validations within the training set of 259 genotypes were obtained for the acoustic linear distance(0.64).Predictions for biparental families using the entire training set varied from low to high accuracy,depending on the family considered.While adding siblings or half-siblings into the training set did not clearly improve predictions,we performed an optimization of the training set size and composition for each validation set.This allowed us to increase prediction accuracies by 0.17 on average,with a maximal accuracy of 0.81 when predicting firmness in the‘Gala’בPink Lady’family.Our results therefore identified key genetic parameters to consider when deploying genomic selection for texture in apple.In particular,we advise to rely on a large training population,with high phenotypic variability from which a‘tailored training population’can be extracted using a priori information on genetic relatedness,in order to predict a specific target population.
基金Agricultural Biotechnology Research Institute of Iran (Iranian Ministry of Ji-had-e-Agriculture)
文摘A few EST-derived STS markers localized on Qfhs.ndsu-3BS, a major QTL for resistance to Fusarium head blight （FHB） in wheat, have been previously identified in the ＇Sumai 3＇/＇Stoa＇ population. In this study, we used a ＇Wangshuibai＇ （resistant）/＇Seri82＇ （susceptible） derived population, linkage group, QTL, and quantitative gene expression analysis to assess the genetic background dependence and stability of the EST-derived STS markers for use in marker aided selection to improve FHB resistance in wheat. Based on our results, a QTL in the map interval of Xsts3B-138_1-Xgwrn493 on chromosome 3BS was detected for FHB resistance, which accounted for up to 16% of the phenotypic variation. BLASTN analysis indicated that Xsts3B-138_1 sequence had significant similarity with the resistance gene analogue. Real-time quantitative PCR showed that the relative expression of Xsts3B-138_1 in ＇Wangshuibai＇ at 96 h after inoculation was 2.6 times higher than ＇Seri82＇. Our results underlined that EST-derived STS3B-138 markers could be predominantly used in marker aided selection to improve FHB resistance in wheat.
文摘The application of population genetic methods in combination with gene mapping strategies can help to identify genes and mutations selected during the evolution from wild plants to crops and to explore the considerable genetic variation still maintained in natural populations.We genotyped a grapevine germplasm collection of 44 wild(Vitis vinifera subsp.sylvestris)and 48 cultivated(V.vinifera subsp.sativa)accessions at 54 K single-nucleotide polymorphisms(SNPs)to perform a whole-genome comparison of the main population genetic statistics.The analysis of Wright Fixation Index(FST)along the whole genome allowed us to identify several putative“signatures of selection”spanning over two thousand SNPs significantly differentiated between sativa and sylvestris.Many of these genomic regions included genes involved in the adaptation to environmental changes.An overall reduction of nucleotide diversity was observed across the whole genome within sylvestris,supporting a small effective population size of the wild grapevine.Tajima’s D resulted positive in both wild and cultivated subgroups,which may indicate an ongoing balancing selection.Association mapping for six domestication-related traits was performed in combination with population genetics,providing further evidence of different perception and response to environmental stresses between sativa and sylvestris.
基金supported by AgroFresh and the National Science Foundation under Award Numbers DBI-0735191 and DBI-1265383.URL:www.cyverse.org.
文摘To decipher the transcriptomic regulation of the on-tree fruit maturation in pear cv.‘Abate Fetel’,a RNA-seq transcription analysis identified 8939 genes differentially expressed across four harvesting stages.These genes were grouped into 11 SOTA clusters based on their transcriptional pattern,of which three included genes upregulated while the other four were represented by downregulated genes.Fruit ripening was furthermore investigated after 1 month of postharvest cold storage.The most important variation in fruit firmness,production of ethylene and volatile organic compounds were observed after 5 days of shelf-life at room temperature following cold storage.The role of ethylene in controlling the ripening of‘Abate Fetel’pears was furthermore investigated through the application of 1-methylcyclopropene,which efficiently delayed the progression of ripening by reducing fruit softening and repressing both ethylene and volatile production.The physiological response of the interference at the ethylene receptor level was moreover unraveled investigating the expression pattern of 12 candidate genes,initially selected to validate the RNA-seq profile.This analysis confirmed the effective role of the ethylene competitor in downregulating the expression of cell wall(PG)and ethylene-related genes(ACS,ACO,ERS1,and ERS2),as well as inducing one element involved in the auxin signaling pathway(Aux/IAA),highlighting a possible cross-talk between these two hormones.The expression patterns of these six elements suggest their use as molecular toolkit to monitor at molecular level the progression of the fruit on-tree maturation and postharvest ripening.
基金supported by the CERCA program from the Generalitat de Catalunya and by the Ministerio de Economía y Competitividad(MINECOgrant AGL2017-87923-R).J.G.B.was the recipient of a JoséCastillejo Mobility Fellowship(CAS18/00186).
文摘To elucidate the physiology underlying the development of superficial scald in pears,susceptible“Blanquilla”fruit was treated with different compounds that either promoted(ethylene)or repressed(1-methylcyclopropene and lovastatin)the incidence of this disorder after 4 months of cold storage.Our data show that scald was negligible for the fruit treated with 1-methylcyclopropene or lovastatin,but highly manifested in untreated(78%incidence)or ethylenetreated fruit(97%incidence).The comparison between the fruit metabolomic profile and transcriptome evidenced a distinct reprogramming associated with each treatment.In all treated samples,cold storage led to an activation of a cold-acclimation-resistance mechanism,including the biosynthesis of very-long-chain fatty acids,which was especially evident in 1-methylcyclopropane-treated fruit.Among the treatments applied,only 1-methylcyclopropene inhibited ethylene production,hence supporting the involvement of this hormone in the development of scald.However,a common repression effect on the PPO gene combined with higher sorbitol content was found for both lovastatin and 1-methylcyclopropene-treated samples,suggesting also a non-ethylene-mediated process preventing the development of this disorder.The results presented in this work represent a step forward to better understand the physiological mechanisms governing the etiology of superficial scald in pears.
基金financially supported by Brazilian Agricultural Research Corporation (Embrapa)-Coordination for the Improvement of Higher Education PersonnelNational Council for Scientific and Technological Development, Federal District Research Support FoundationFoundation for Scientific and Technological Development of Mato Grosso do Sul State
文摘Rice genes OsDjA2 and OsERF104,encoding a chaperone protein and an APETELA2/ethylene-responsive factor,respectively,are strongly induced in a compatible interaction with blast fungus,and also have function in plant susceptibility validated through gene silencing.Here,we reported the CRISPR/Cas9 knockout of OsDjA2 and OsERF104 genes resulting in considerable improvement of blast resistance.A total of 15 OsDjA2(62.5%)and 17 OsERF104(70.8%)T_(0)transformed lines were identified from 24 regenerated plants for each target and used in downstream experiments.Phenotyping of homozygous T1 mutant lines revealed not only a significant decrease in the number of blast lesions but also a reduction in the percentage of diseased leaf area,compared with the infected control plants.Our results supported CRISPR/Cas9-mediated target mutation in rice susceptibility genes as a potential and alternative breeding strategy for building resistance to blast disease.
文摘Genetic diversity evaluation of mutant lines is essential to facilitate their conservation and utility in breeding programs. Characterization of plant genotypes using morphological markers has limitations which make the procedure inefficient. Application of molecular tools for characterization and diversity assessment has been found useful to complement phenotypic evaluation of plant population. Therefore genetic diversity of some cowpea mutant lines was studied using simple sequence repeats (SSR) markers. DNA barcoding marker, ribulose-1,5-bisphosphate carboxylase(rbcL) of the chloroplast DNA (cpDNA) was also used for characterization and identification of the mutants to species level. The mean polymorphic information content (0.51) obtained from the microsatellites showed high polymorphism in accessing wide genetic diversity among the mutants and their parents. Dendrogram generated revealed 8 groups with most mutants clustered separately from their parents. Sequence analysis revealed insertions/deletions (InDels) and base substitutions as the two main classes of mutations induced in the plastid DNA of the mutants studied. The nucleotide frequencies were 26.95% (A), 34.43% (T), 24.09% (C) and 14.53% (G). A total of 61.38% AT rich region was identified, while GC rich region was found to be 38.62%. Highest rate of mutations were observed in region 3 - 4 indicating that the region is less conserved in cowpea rbcL gene. The present study proved that SSR markers are useful for the genetic diversity assessment of cowpea mutants. It also proved the efficiency of rbcL markers in mutants’ identification. The results indicate that the mutants are valuable genetic resources that have been developed to widen cowpea genetic base.
文摘Malus x domestica microRNA MdmiR285N is a potential key regulator of plant immunity,as it has been predicted to target 35 RNA transcripts coding for different disease resistance proteins involved in plant defense to pathogens.In this study,the promoter region of MdmiR285N was isolated from the apple genome and analyzed in silico to detect potential regulatory regions controlling its transcription.A complex network of putative regulatory elements involved in plant growth and development,and in response to different hormones and stress conditions,was identified.Activity of theβ-Glucoronidase(GUS)reporter gene driven by the promoter of MdmiR285N was examined in transgenic apple,demonstrating that MdmiR285N was expressed during the vegetative growth phase.Similarly,in transgenic Arabidopsis thaliana,spatial and temporal patterns of GUS expression revealed that MdmiR285N was differentially regulated during seed germination,vegetative phase change,and reproductive development.To elucidate the role of MdmiR285N in plant immunity,MdmiR285N expression in wild-type apple plants and GUS activity in transgenic apple and Arabidopsis thaliana plants were monitored in response to Erwinia amylovora and Pseudomonas syringae pv.Tomato DC3000.A significant decrease of MdmiR285N levels and GUS expression was observed during host-pathogen infections.Overall,these data suggest that MdmiR285N is involved in the biotic stress response,plant growth,and reproductive development.
文摘One of the major causes of congenital hypophosphatemic rickets is the X-linked hypophosphatemic rickets (XHR), due to a defect on PHEX gene. The XHR increases the renal elimination of phosphate, that condition leads a defective mineralization of bones and also affects the growth in children. Clinical diagnosis should be suspected in children with signs of rickets and hypophosphatemia with normal calcium levels. We describe clinical characteristics and genetic results of four patients diagnosed and treated in our Nephrology Section. All patients have a “de novo” XHR as none familiars are affected. Early diagnosis should be suspected before the bone deformities have been submitted and the growth would have been impaired.
文摘We hypothesize that individuals with genetic predisposition to Substance Use Disorder (SUD) may have greater likelihood of experiencing work related accidents. We further hypothesize that high risk populations will carry single or multiple polymorphisms associated with brain reward circuitry and/or brain reward cascade, including: Dopaminergic (i.e. DRD2 receptor genes);Serotonergic (i.e. 5-HTT2 receptor genes);Endorphinergic (i.e. pre-enkephalin genes);Gabergic (i.e. GABAA receptor genes);Neurotransmitter Metabolizing genes (i.e. MAO and COMT genes) among others (GARSRXTM). Analgesic addiction as well as “pseudoaddiction” must be treated to improve pain control and its management. We propose that non-pharmacological alternatives to pain relief, in high risk, addiction-prone individuals, are Electrotherapeutic Device(s) and Programs. We further propose patented KB220Z, a nutraceutical designed to release dopamine at the nucleus accumbens, will reduce craving behavior, in genetically programmed individuals. By utilizing both alternatives in DNA analyzed injured workers, a reduction in analgesic addiction (genuine or pseudo) leads to improved health and quicker return to work. We also hypothesize that this novel approach will impact costs related to injuries in the workforce. Effective management of chronic pain, especially in high addiction-prone workforce populations, is possible in spite of being particularly elusive. A series of factors encumber pain assessment and management, including analgesia addiction, pharmacogenomic response to pain medications, and genetically inherited factors involving gene polymorphisms. Additional research is required to test these stipulated hypotheses related to genetic proneness to addiction, but also proneness to accidents in the workplace and reduction of craving behavior. Our hypothesis that genotyping coupled with both KB220ZTM and the pharmaceutical-free Electrotherapy, will reduce iatrogenic induced analgesia addiction. This approach will achieve attainable effective pain management and quicker return to work. We propose outcomes such as the Reward Deficiency System SolutionTM may become an adjunct in the war against iatrogenic pain medication addiction.
文摘The objective of this paper is to present a new ideotype of grain legume cultivar and show improvements in breeding from the introduction of the terminal inflorescence （ti） gene in field bean, and the introduction of the restricted branching （rb） gene in three lupin crops--narrow-leafed lupin, white lupin and yellow lupin. Field trials using control cultivars were conducted at the Research Center for Cultivar Testing in Poland. For each species, different trial periods were selected in which new cultivars with ti/rb genes were registered. A breeding progress was estimated by a comparison of a new cultivar to control--bridge cultivar to the next trial period. Over the past twenty years cultivar improvement using ti/rb genes has proceeded differently in these species. The newest, self-completing legume cultivars have yields comparable to traditional ones and generally are earlier and more uniform when mature. This paper shows that breeding progress in rb yellow lupin is outstanding; in rb narrow-leafed lupin and ti field bean is favorable; and in rb white lupin is moderate.
文摘In 2010,a major scientific milestone was achieved for tree fruit crops:publication of the first draft whole genome sequence(WGS)for apple(Malus domestica).This WGS,v1.0,was valuable as the initial reference for sequence information,fine mapping,gene discovery,variant discovery,and tool development.A new,high quality apple WGS,GDDH13 v1.1,was released in 2017 and now serves as the reference genome for apple.Over the past decade,these apple WGSs have had an enormous impact on our understanding of apple biological functioning,trait physiology and inheritance,leading to practical applications for improving this highly valued crop.Causal gene identities for phenotypes of fundamental and practical interest can today be discovered much more rapidly.Genome-wide polymorphisms at high genetic resolution are screened efficiently over hundreds to thousands of individuals with new insights into genetic relationships and pedigrees.High-density genetic maps are constructed efficiently and quantitative trait loci for valuable traits are readily associated with positional candidate genes and/or converted into diagnostic tests for breeders.We understand the species,geographical,and genomic origins of domesticated apple more precisely,as well as its relationship to wild relatives.The WGS has turbo-charged application of these classical research steps to crop improvement and drives innovative methods to achieve more durable,environmentally sound,productive,and consumer-desirable apple production.This review includes examples of basic and practical breakthroughs and challenges in using the apple WGSs.Recommendations for“what’s next”focus on necessary upgrades to the genome sequence data pool,as well as for use of the data,to reach new frontiers in genomics-based scientific understanding of apple.
文摘Morphological variation of snails from the genus Trochulus is so huge that their taxonomy is unclear. The greatest variability concerns forms hispidus and sericeus/plebeius, which are often considered as separate species. To evidence the species barriers, we carried out crossbreeding ex- periments between these two sympatric morphs. Moreover, we compared the shell morphology of laboratory-bred offspring with their wild parents to test if the variation can be explained by the phenotypic plasticity model. We found that the two Trochulus morphs show no reproductive bar- riers. The fecundity rates, the mean clutch size, and F~ viability observed for all crosses were not significantly different. In hybrid crosses （in F2 generation）, we also recorded reproduction compati- bility, similar fecundity, and hatching success as in their parents. Accordingly, phylogenetic ana- lyses revealed the significant grouping of sequences from these different morphs and supported no constrains in reproduction between them. Comparison of shell morphology between wild and laboratory samples showed that various characters appeared highly plastic. The average shell shape of the hispidus morph changed significantly from flat with wide umbilicus to elevated with narrower umbilicus such as in the sericeus/plebeius morph. All these findings indicate that the examined morphs do not represent separate biological species and the evolutionary process is not advanced enough to separate their genetic pool. Therefore, phenotypic plasticity has played a sig- nificant role in the evolution of Trochulus shell polymorphism. The two morphs can evolve inde- pendently in separate phylogenetic lineages under the influence of local environmental conditions.
基金This study was supported by the Collaborative Research Fund(grant no.C5079-21G)of the Research Grants Council of Hong Kong,China.
文摘Despite most COVID-19 infections being asymptomatic,China's Mainland had a high increase in symptomatic cases at the end of 2022.In this study,we examine China's sudden COVID-19 symptomatic surge using a conceptual SIR-based model.Our model considers the epidemiological characteristics of SARS-CoV-2,particularly variolation,from non-pharmaceutical intervention(facial masking and social distance),demography,and disease mortality in China's Mainland.The increase in symptomatic proportions in China may be attributable to(1)higher sensitivity and vulnerability during winter and(2)enhanced viral inhalation due to spikes in SARS-CoV-2 infections(high transmissibility).These two reasons could explain China's high symptomatic proportion of COVID-19 in December 2022.Our study,therefore,can serve as a decision-support tool to enhance SARS-CoV-2 prevention and control efforts.Thus,we highlight that facemask-induced variolation could potentially reduces transmissibility rather than severity in infected individuals.However,further investigation is required to understand the variolation effect on disease severity.
基金DH was supported by Hong Kong Research Grants Council Collaborative Research Fund(C5079-21G).
文摘In late March 2020,SARS-CoV-2 arrived in Manaus,Brazil,and rapidly developed into a large-scale epidemic that collapsed the local health system and resulted in extreme death rates.Several key studies reported that∼76%of residents of Manaus were infected(attack rate AR≃76%)by October 2020,suggesting protective herd immunity had been reached.Despite this,an unexpected second wave of COVID-19 struck again in November and proved to be larger than the first,creating a catastrophe for the unprepared population.It has been suggested that this could be possible if the second wave was driven by reinfections.However,it is widely reported that reinfections were at a low rate(before the emergence of Omicron),and reinfections tend to be mild.Here,we use novel methods to model the epidemic from mortality data without considering reinfection-caused deaths and evaluate the impact of interventions to explain why the second wave appeared.The method fits a“flexible”reproductive numberR_(0)(t)that changes over the epidemic,and it is demonstrated that the method can successfully reconstruct R_(0)(t)from simulated data.For Manaus,the method finds AR≃34%by October 2020 for the first wave,which is far less than required for herd immunity yet in-line with seroprevalence estimates.The work is complemented by a two-strain model.Using genomic data,the model estimates transmissibility of the new P.1 virus lineage as 1.9 times higher than that of the non-P.1.Moreover,an age class model variant that considers the high mortality rates of older adults show very similar results.These models thus provide a reasonable explanation for the two-wave dynamics in Manaus without the need to rely on large reinfection rates,which until now have only been found in negligible to moderate numbers in recent surveillance efforts.
