BACKGROUND Alterations in plasma and intestinal metabolites contribute to the pathogenesis and progression of alcohol-related liver cirrhosis(ALC).AIM To explore the common and different metabolites in the plasma and ...BACKGROUND Alterations in plasma and intestinal metabolites contribute to the pathogenesis and progression of alcohol-related liver cirrhosis(ALC).AIM To explore the common and different metabolites in the plasma and feces of patients with ALC and evaluate their clinical implications.METHODS According to the inclusion and exclusion criteria,27 patients with ALC and 24 healthy controls(HCs)were selected,and plasma and feces samples were collected.Liver function,blood routine,and other indicators were detected with automatic biochemical and blood routine analyzers.Liquid chromatography-mass spectrometry was used to detect the plasma and feces metabolites of the two groups and the metabolomics of plasma and feces.Also,the correlation between metabolites and clinical features was analyzed.RESULTS More than 300 common metabolites were identified in the plasma and feces of patients with ALC.Pathway analysis showed that these metabolites are enriched in bile acid and amino acid metabolic pathways.Compared to HCs,patients with ALC had a higher level of glycocholic acid(GCA)and taurocholic acid(TCA)in plasma and a lower level of deoxycholic acid(DCA)in the feces,while L-threonine,L-phenylalanine,and L-tyrosine increased simultaneously in plasma and feces.GCA,TCA,L-methionine,L-phenylalanine,and L-tyrosine in plasma were positively correlated with total bilirubin(TBil),prothrombin time(PT),and maddrey discriminant function score(MDF)and negatively correlated with cholinesterase(CHE)and albumin(ALB).The DCA in feces was negatively correlated with TBil,MDF,and PT and positively correlated with CHE and ALB.Moreover,we established a P/S BA ratio of plasma primary bile acid(GCA and TCA)to fecal secondary bile acid(DCA),which was relevant to TBil,PT,and MDF score.CONCLUSION The enrichment of GCA,TCA,L-phenylalanine,L-tyrosine,and L-methionine in the plasma of patients with ALC and the reduction of DCA in feces were related to the severity of ALC.These metabolites may be used as indicators to evaluate the progression of alcohol-related liver cirrhosis.展开更多
The disequilibrium between the production of reactive oxygen(ROS) and nitrogen(RNS) species and their elimination by protective mechanisms leads to oxidative stress. Mitochondria are the main source of ROS as by-produ...The disequilibrium between the production of reactive oxygen(ROS) and nitrogen(RNS) species and their elimination by protective mechanisms leads to oxidative stress. Mitochondria are the main source of ROS as by-products of electron transport chain. Most of the time the intestine responds adequately against the oxidative stress, but with aging or under conditions that exacerbate the ROS and/or RNS production, the defenses are not enough and contribute to developing intestinal pathologies. The endogenous antioxidant defense system in gut includes glutathione(GSH) and GSH-dependent enzymes as major components. When the ROS and/or RNS production is exacerbated, oxidative stress occurs and the intestinal Ca2+ absorption is inhibited. GSH depleting drugs such as DLbuthionine-S,R-sulfoximine, menadione and sodium deoxycholate inhibit the Ca2+ transport from lumen to blood by alteration in the protein expression and/or activity of molecules involved in the Ca2+ transcellular and paracellular pathways through mechanisms of oxidative stress, apoptosis and/or autophagy. Quercetin, melatonin, lithocholic and ursodeoxycholic acids block the effect of those drugs in experimental animals by their antioxidant, anti-apoptotic and/or anti-autophagic properties. Therefore, they may become drugs of choice for treatment of deteriorated intestinal Ca2+ absorption under oxidant conditions such as aging, diabetes, gut inflammation and other intestinal disorders.展开更多
Azilsartan(AZL), a poorly soluble drug, was considered to be fit for nanocrystals to improve its solubility. Our study intended to prepare AZL nanocrystals by means of bead milling method. Eight stabilizers or their b...Azilsartan(AZL), a poorly soluble drug, was considered to be fit for nanocrystals to improve its solubility. Our study intended to prepare AZL nanocrystals by means of bead milling method. Eight stabilizers or their binary combination and the milling time were set to be variable factors to optimize AZL nanosuspension formulation, and six types of freezedrying supports were investigated to reduce the aggregation of particles during the solidification. AZL nanocrystals with or without sodium deoxycholate(NaDC) as combined stabilizer with Poloxamer 188(F68) were prepared owning mean particle sizes of about 300 nm and 460 nm. During the screening processes, the formulation containing NaDC showed a smaller particle size and better stability during lyophilization. The irregular shape and crystal form changing in AZL nanocrystals were discovered by various characterizations. And with physical mixture as reference, nanocrystals showed its improvement about in-vitro dissolution and in-vivo bioavailability. In conclusion, the nanocrystals of AZL could be prepared well in our study. Additionally, our results suggested that NaDC was an appreciated excipient on the nanocrystals platform, which can exhibit the abilities of size-reduction and stabilitymaintaining on freeze-drying.展开更多
AIM:To investigate the close parallels between our novel diet-related mouse model of colon cancer and human colon cancer.METHODS:Twenty-two wild-type female mice(ages 6-8 wk)were fed the standard control diet(AIN-93G)...AIM:To investigate the close parallels between our novel diet-related mouse model of colon cancer and human colon cancer.METHODS:Twenty-two wild-type female mice(ages 6-8 wk)were fed the standard control diet(AIN-93G)and an additional 22 female mice(ages 6-8 wk)were fed the control diet supplemented with 0.2%deoxycho-lic acid[diet+deoxycholic acid(DOC)]for 10 mo.Tu-mors occurred in the colons of mice fed diet+DOC and showed progression to colon cancer[adenocarcinoma(AC)].This progression is through the stages of tubular adenoma(TA),TA with high grade dysplasia or ad-enoma with sessile serrated morphology,intramucosal AC,AC stage T1,and AC stage T2.The mouse tumors were compared to human tumors at the same stages by histopathological analysis.Sections of the small and large intestines of mice and humans were evaluated for glandular architecture,cellular and nuclear morphology including cellular orientation,cellular and nuclear atyp-ia,pleomorphism,mitotic activity,frequency of goblet cells,crypt architecture,ulceration,penetration of crypts through the muscularis mucosa and presence of malignant crypts in the muscularis propria.In addition,preserved colonic tissues from genetically similar male mice,obtained from a prior experiment,were analyzed by immunohistochemistry.The male mice had been fed the control diet or diet+DOC.Four molecular markers were evaluated:8-OH-dG,DNA repair protein ERCC1,autophagy protein beclin-1 and the nuclear location of beta-catenin in the stem cell region of crypts.Also,male mice fed diet+DOC plus 0.007%chlorogenic acid(diet+DOC+CGA)were evaluated for ERCC1,beclin-1 and nuclear location of beta-catenin.RESULTS:Humans with high levels of diet-relatedDOC in their colons are at a substantially increased riskof developing colon cancer.The mice fed diet+DOChad levels of DOC in their colons comparable to that ofhumans on a high fat diet.The 22 mice without addedDOC in their diet had no colonic tumors while 20 ofthe 22 mice(91%)fed diet+DOC developed colonictumors.Furthermore,the tumors in 10 of these mice(45%of mice)included an adenocarcinoma.All micewere free of cancers of the small intestine.Histopatho-logically,the colonic tumor types in the mice werevirtually identical to those in humans.In humans,char-acteristic aberrant changes in molecular markers can be detected both in field defects surrounding cancers(from which cancers arise)and within cancers.In thecolonic tissues of mice fed diet+DOC similar changesin biomarkers appeared to occur.Thus,8-OH-dG wasincreased,DNA repair protein ERCC1 was decreased,autophagy protein beclin-1 was increased and,in thestem cell region at the base of crypts there was sub-stantial nuclear localization of beta-catenin as well asincreased cytoplasmic beta-catenin.However,in micefed diet+DOC+CGA(with reduced frequency ofcancer)and evaluated for ERCC1,beclin-1,and beta-catenin in the stem cell region of crypts,mouse tissueshowed amelioration of the aberrancies,suggestingthat chlorogenic acid is protective at the molecular levelagainst colon cancer.This is the first diet-related modelof colon cancer that closely parallels human progressionto colon cancer,both at the histomorphological level aswell as in its molecular profile.CONCLUSION:The diet-related mouse model of coloncancer parallels progression to colon cancer in humans,and should be uniquely useful in model studies of pre-vention and therapeutics.展开更多
Food-borne diseases are the main public health problem throughout the world. Milk is important component of human diet including fats, proteins, vitamins and minerals. It is a best source of calcium and phosphorus. Di...Food-borne diseases are the main public health problem throughout the world. Milk is important component of human diet including fats, proteins, vitamins and minerals. It is a best source of calcium and phosphorus. Different types of pathogenic bacteria like S. aureus and Salmonella enter in milk and then multiply, after multiplication they become active in causing diseases. These bacteria create serious problems for human health. This study aimed to isolate and identify pathogenic bacteria Staphylococcus aureus and Salmonella from raw milk samples of different cities of Pakistan. Primary screening of raw milk samples was done on the basis of morphological, cultural and biochemical techniques. The final identification was made using 16SrRNA sequence analysis. A total of 200 raw milk samples were collected from different cities of Pakistan. Selective medium xylose lysine deoxycholate agar (XLD) and Mannitol salt agar were used for the identification of Salmonella sp. and S. aureus. Staphylococcus aureus produced yellow colonies with yellow zones on Mannitol salt agar. Staphylococcus aureus exhibited gram-positive character with purple coloration and it was detected as cocci-shaped. Biochemically 91 (45%) samples enhibited Catalase, Coagulase, DNase, Urease, Citrate, fermentation tests positive and indole, oxidase and H2S tests negative with nonmotile character, indicating the presence of Staphylococcus aureus. Salmonella sp. was detected as gram negative rods with pink coloration on gram staining. Biochemically 87 (43%) samples revealed catalase, citrate, H2S and fermentation tests positive while oxidase, DNase, Indole and urease tests negative, indicating the presence of Salmonella sp. in these samples. Of the 200 samples tested, 43% were positive for Salmonella, while 45% samples were contaminated with S. aureus. The 16SrRNA sequence analysis confirmed the results of biochemical and cultural characterization by depicting 99% identity of samples with S. aureus and 98% identity with Salmonella spp. The occurrence of high percentage of these pathogenic bacteria in raw milk may be linked to its contamination at the time of collection, processing, strorage and distribution. This quantitative data could be utilized to better establish the appropriate levels of protection for raw milk, dairy products and processing technologies.展开更多
Methylene blue(MB) is a hydrophobic drug molecule, having importance both as a staining reagent and pharmaceutical agent. MB is strongly fluorescent, with an emission peak at 686 nm(λ_(ex)665 nm). In the study,the po...Methylene blue(MB) is a hydrophobic drug molecule, having importance both as a staining reagent and pharmaceutical agent. MB is strongly fluorescent, with an emission peak at 686 nm(λ_(ex)665 nm). In the study,the possibility of MB as an extrinsic fluorophore to study the micellization behavior of bile salts(BSs) was carried out. Since BSs are drug delivery systems, the solubilization of hydrophobic MB drug molecule by BSs was achieved and the nature of association of MB with BS media, namely sodium cholate(Na C) and sodium deoxycholate(Na DC) was evaluated. Change in the photophysical properties of MB is monitored through fluorescence intensity and fluorescence anisotropy at emission peak, 686 nm of MB. Molecular mechanics calculations were carried out to evaluate the MB–BS association. The estimated heat of formation, ΔH_f values are –625.19 kcal/mol for MB–Na C and –757.48 kcal/mol for MB–Na DC. The photophysical study also revealed that MB reports the step-wise aggregation pattern of BSs media, as an extrinsic fluorescence probe.展开更多
A hydrogel is formed by the self-assembly of sodium deoxycholate (NaDC) in aqueous solution with sodium chloride at pH-7.0. The NaDC hydrogel made of the three-dimensional network of nanofibers shows pH-dependent swel...A hydrogel is formed by the self-assembly of sodium deoxycholate (NaDC) in aqueous solution with sodium chloride at pH-7.0. The NaDC hydrogel made of the three-dimensional network of nanofibers shows pH-dependent swelling behaviors. Polystyrene particles with a diameter of 100 nm and doxorubicin hydrochloride (DOX) can be easily loaded into the NaDC hydrogel through swelling. By using the loaded polystyrene particles as a light scattering probe, we study the microrheology of the NaDC hydrogel, showing complex viscoelastic properties. The viscous component dominates at both low and high frequencies, while the elastic component dominates in the intermediate range. The cavity size of the nanofiber network can also be estimated to be ~180 nm. We show that the loaded DOX can be slowly released from the hydrogels into aqueous solution. The release profile of DOX is found to depend on the pH value of the solution.展开更多
Background:Clostridium perfringens-induced chicken necrotic enteritis(NE)is responsible for substantial economic losses worldwide annually.Recently,as a result of antibiotic growth promoter prohibition,the prevalence ...Background:Clostridium perfringens-induced chicken necrotic enteritis(NE)is responsible for substantial economic losses worldwide annually.Recently,as a result of antibiotic growth promoter prohibition,the prevalence of NE in chickens has reemerged.This study was aimed to reduce NE through titrating dietary deoxycholic acid(DCA)as an effective antimicrobial alternative.Materials and methods:Day-old broiler chicks were assigned to six groups and fed diets supplemented with 0(basal diet),0.8,1.0 and 1.5 g/kg(on top of basal diet)DCA.The birds were challenged with Eimeria maxima(20,000 oocysts/bird)at d 18 and C.perfringens(109 CFU/bird per day)at d 23,24,and 25 to induce NE.The birds were sacrificed at d 26 when ileal tissue and digesta were collected for analyzing histopathology,mRNA accumulation and C.perfringens colonization by real-time PCR,targeted metabolomics of bile acids,fluorescence in situ hybridization(FISH),or terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assay.Results:At the cellular level,birds infected with E.maxima and C.perfringens developed subclinical NE and showed shortening villi,crypt hyperplasia and immune cell infiltration in ileum.Dietary DCA alleviated the NE-induced ileal inflammation in a dose-dependent manner compared to NE control birds.Consistent with the increased histopathological scores,subclinical NE birds suffered body weight gain reduction compared to the uninfected birds,an effect attenuated with increased doses of dietary DCA.At the molecular level,the highest dose of DCA at 1.5 g/kg reduced C.perfringens luminal colonization compared to NE birds using PCR and FISH.Furthermore,the dietary DCA reduced subclinical NE-induced intestinal inflammatory gene expression and cell apoptosis using PCR and TUNEL assays.Upon further examining ileal bile acid pool through targeted metabolomics,subclinical NE reduced the total bile acid level in ileal digesta compared to uninfected birds.Notably,dietary DCA increased total bile acid and DCA levels in a dose-dependent manner compared to NE birds.Conclusion:These results indicate that DCA attenuates NE-induced intestinal inflammation and bile acid reduction and could be an effective antimicrobial alternative against the intestinal disease.展开更多
A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms. Instead of using toxic phosgene, the triphosgene was employed in synthesis ...A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms. Instead of using toxic phosgene, the triphosgene was employed in synthesis of the molecular tweezers receptors. These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.展开更多
Deoxycholic acid(DCA)has been authorized by the Federal Drug Agency for cosmetic reduction of redundant submental fat.The hydroxylated product(6β-OH DCA)was developed to improve the solubility and pharmaceutic proper...Deoxycholic acid(DCA)has been authorized by the Federal Drug Agency for cosmetic reduction of redundant submental fat.The hydroxylated product(6β-OH DCA)was developed to improve the solubility and pharmaceutic properties of DCA for further applications.Herein,a combinatorial catalytic strategy was applied to construct a powerful Cytochrome P450 biocatalyst(CYP107D1,OleP)to convert DCA to 6β-OH DCA.Firstly,the weak expression of OleP was significantly improved using pRSFDuet-1 plasmid in the E.coli C41(DE3)strain.Next,the supply of heme was enhanced by the moderate overexpression of crucial genes in the heme biosynthetic pathway.In addition,a new biosensor was developed to select the appropriate redox partner.Furthermore,a cost-effective whole-cell catalytic system was constructed,resulting in the highest reported conversion rate of 6β-OH DCA(from 4.8%to 99.1%).The combinatorial catalytic strategies applied in this study provide an efficient method to synthesize high-value-added hydroxylated compounds by P450s.展开更多
基金Supported by National Key R&D Program of China,No.21YFC2301801Capital's Funds for Health Improvement and Research of China,No.2020-1-2171.
文摘BACKGROUND Alterations in plasma and intestinal metabolites contribute to the pathogenesis and progression of alcohol-related liver cirrhosis(ALC).AIM To explore the common and different metabolites in the plasma and feces of patients with ALC and evaluate their clinical implications.METHODS According to the inclusion and exclusion criteria,27 patients with ALC and 24 healthy controls(HCs)were selected,and plasma and feces samples were collected.Liver function,blood routine,and other indicators were detected with automatic biochemical and blood routine analyzers.Liquid chromatography-mass spectrometry was used to detect the plasma and feces metabolites of the two groups and the metabolomics of plasma and feces.Also,the correlation between metabolites and clinical features was analyzed.RESULTS More than 300 common metabolites were identified in the plasma and feces of patients with ALC.Pathway analysis showed that these metabolites are enriched in bile acid and amino acid metabolic pathways.Compared to HCs,patients with ALC had a higher level of glycocholic acid(GCA)and taurocholic acid(TCA)in plasma and a lower level of deoxycholic acid(DCA)in the feces,while L-threonine,L-phenylalanine,and L-tyrosine increased simultaneously in plasma and feces.GCA,TCA,L-methionine,L-phenylalanine,and L-tyrosine in plasma were positively correlated with total bilirubin(TBil),prothrombin time(PT),and maddrey discriminant function score(MDF)and negatively correlated with cholinesterase(CHE)and albumin(ALB).The DCA in feces was negatively correlated with TBil,MDF,and PT and positively correlated with CHE and ALB.Moreover,we established a P/S BA ratio of plasma primary bile acid(GCA and TCA)to fecal secondary bile acid(DCA),which was relevant to TBil,PT,and MDF score.CONCLUSION The enrichment of GCA,TCA,L-phenylalanine,L-tyrosine,and L-methionine in the plasma of patients with ALC and the reduction of DCA in feces were related to the severity of ALC.These metabolites may be used as indicators to evaluate the progression of alcohol-related liver cirrhosis.
基金Supported by Dr.Nori Tolosa de Talamoni from CONICET,No.PIP 2013-2015 and No.SECYT(UNC)2016,Argentina
文摘The disequilibrium between the production of reactive oxygen(ROS) and nitrogen(RNS) species and their elimination by protective mechanisms leads to oxidative stress. Mitochondria are the main source of ROS as by-products of electron transport chain. Most of the time the intestine responds adequately against the oxidative stress, but with aging or under conditions that exacerbate the ROS and/or RNS production, the defenses are not enough and contribute to developing intestinal pathologies. The endogenous antioxidant defense system in gut includes glutathione(GSH) and GSH-dependent enzymes as major components. When the ROS and/or RNS production is exacerbated, oxidative stress occurs and the intestinal Ca2+ absorption is inhibited. GSH depleting drugs such as DLbuthionine-S,R-sulfoximine, menadione and sodium deoxycholate inhibit the Ca2+ transport from lumen to blood by alteration in the protein expression and/or activity of molecules involved in the Ca2+ transcellular and paracellular pathways through mechanisms of oxidative stress, apoptosis and/or autophagy. Quercetin, melatonin, lithocholic and ursodeoxycholic acids block the effect of those drugs in experimental animals by their antioxidant, anti-apoptotic and/or anti-autophagic properties. Therefore, they may become drugs of choice for treatment of deteriorated intestinal Ca2+ absorption under oxidant conditions such as aging, diabetes, gut inflammation and other intestinal disorders.
基金financially supported by Science research project of Department of Education Liaoning Province(No.L2013390)
文摘Azilsartan(AZL), a poorly soluble drug, was considered to be fit for nanocrystals to improve its solubility. Our study intended to prepare AZL nanocrystals by means of bead milling method. Eight stabilizers or their binary combination and the milling time were set to be variable factors to optimize AZL nanosuspension formulation, and six types of freezedrying supports were investigated to reduce the aggregation of particles during the solidification. AZL nanocrystals with or without sodium deoxycholate(NaDC) as combined stabilizer with Poloxamer 188(F68) were prepared owning mean particle sizes of about 300 nm and 460 nm. During the screening processes, the formulation containing NaDC showed a smaller particle size and better stability during lyophilization. The irregular shape and crystal form changing in AZL nanocrystals were discovered by various characterizations. And with physical mixture as reference, nanocrystals showed its improvement about in-vitro dissolution and in-vivo bioavailability. In conclusion, the nanocrystals of AZL could be prepared well in our study. Additionally, our results suggested that NaDC was an appreciated excipient on the nanocrystals platform, which can exhibit the abilities of size-reduction and stabilitymaintaining on freeze-drying.
基金Supported by National Institutes of Health,No.5 R01 CA119087Arizona Biomedical Research Commission,No.0803+1 种基金Veterans Affairs Merit Review,No.0142administered by the Southern Arizona Veterans Affairs Health Care System
文摘AIM:To investigate the close parallels between our novel diet-related mouse model of colon cancer and human colon cancer.METHODS:Twenty-two wild-type female mice(ages 6-8 wk)were fed the standard control diet(AIN-93G)and an additional 22 female mice(ages 6-8 wk)were fed the control diet supplemented with 0.2%deoxycho-lic acid[diet+deoxycholic acid(DOC)]for 10 mo.Tu-mors occurred in the colons of mice fed diet+DOC and showed progression to colon cancer[adenocarcinoma(AC)].This progression is through the stages of tubular adenoma(TA),TA with high grade dysplasia or ad-enoma with sessile serrated morphology,intramucosal AC,AC stage T1,and AC stage T2.The mouse tumors were compared to human tumors at the same stages by histopathological analysis.Sections of the small and large intestines of mice and humans were evaluated for glandular architecture,cellular and nuclear morphology including cellular orientation,cellular and nuclear atyp-ia,pleomorphism,mitotic activity,frequency of goblet cells,crypt architecture,ulceration,penetration of crypts through the muscularis mucosa and presence of malignant crypts in the muscularis propria.In addition,preserved colonic tissues from genetically similar male mice,obtained from a prior experiment,were analyzed by immunohistochemistry.The male mice had been fed the control diet or diet+DOC.Four molecular markers were evaluated:8-OH-dG,DNA repair protein ERCC1,autophagy protein beclin-1 and the nuclear location of beta-catenin in the stem cell region of crypts.Also,male mice fed diet+DOC plus 0.007%chlorogenic acid(diet+DOC+CGA)were evaluated for ERCC1,beclin-1 and nuclear location of beta-catenin.RESULTS:Humans with high levels of diet-relatedDOC in their colons are at a substantially increased riskof developing colon cancer.The mice fed diet+DOChad levels of DOC in their colons comparable to that ofhumans on a high fat diet.The 22 mice without addedDOC in their diet had no colonic tumors while 20 ofthe 22 mice(91%)fed diet+DOC developed colonictumors.Furthermore,the tumors in 10 of these mice(45%of mice)included an adenocarcinoma.All micewere free of cancers of the small intestine.Histopatho-logically,the colonic tumor types in the mice werevirtually identical to those in humans.In humans,char-acteristic aberrant changes in molecular markers can be detected both in field defects surrounding cancers(from which cancers arise)and within cancers.In thecolonic tissues of mice fed diet+DOC similar changesin biomarkers appeared to occur.Thus,8-OH-dG wasincreased,DNA repair protein ERCC1 was decreased,autophagy protein beclin-1 was increased and,in thestem cell region at the base of crypts there was sub-stantial nuclear localization of beta-catenin as well asincreased cytoplasmic beta-catenin.However,in micefed diet+DOC+CGA(with reduced frequency ofcancer)and evaluated for ERCC1,beclin-1,and beta-catenin in the stem cell region of crypts,mouse tissueshowed amelioration of the aberrancies,suggestingthat chlorogenic acid is protective at the molecular levelagainst colon cancer.This is the first diet-related modelof colon cancer that closely parallels human progressionto colon cancer,both at the histomorphological level aswell as in its molecular profile.CONCLUSION:The diet-related mouse model of coloncancer parallels progression to colon cancer in humans,and should be uniquely useful in model studies of pre-vention and therapeutics.
文摘Food-borne diseases are the main public health problem throughout the world. Milk is important component of human diet including fats, proteins, vitamins and minerals. It is a best source of calcium and phosphorus. Different types of pathogenic bacteria like S. aureus and Salmonella enter in milk and then multiply, after multiplication they become active in causing diseases. These bacteria create serious problems for human health. This study aimed to isolate and identify pathogenic bacteria Staphylococcus aureus and Salmonella from raw milk samples of different cities of Pakistan. Primary screening of raw milk samples was done on the basis of morphological, cultural and biochemical techniques. The final identification was made using 16SrRNA sequence analysis. A total of 200 raw milk samples were collected from different cities of Pakistan. Selective medium xylose lysine deoxycholate agar (XLD) and Mannitol salt agar were used for the identification of Salmonella sp. and S. aureus. Staphylococcus aureus produced yellow colonies with yellow zones on Mannitol salt agar. Staphylococcus aureus exhibited gram-positive character with purple coloration and it was detected as cocci-shaped. Biochemically 91 (45%) samples enhibited Catalase, Coagulase, DNase, Urease, Citrate, fermentation tests positive and indole, oxidase and H2S tests negative with nonmotile character, indicating the presence of Staphylococcus aureus. Salmonella sp. was detected as gram negative rods with pink coloration on gram staining. Biochemically 87 (43%) samples revealed catalase, citrate, H2S and fermentation tests positive while oxidase, DNase, Indole and urease tests negative, indicating the presence of Salmonella sp. in these samples. Of the 200 samples tested, 43% were positive for Salmonella, while 45% samples were contaminated with S. aureus. The 16SrRNA sequence analysis confirmed the results of biochemical and cultural characterization by depicting 99% identity of samples with S. aureus and 98% identity with Salmonella spp. The occurrence of high percentage of these pathogenic bacteria in raw milk may be linked to its contamination at the time of collection, processing, strorage and distribution. This quantitative data could be utilized to better establish the appropriate levels of protection for raw milk, dairy products and processing technologies.
基金DST–SERB, India (SB/FT/CS-032/2012) for the financial support
文摘Methylene blue(MB) is a hydrophobic drug molecule, having importance both as a staining reagent and pharmaceutical agent. MB is strongly fluorescent, with an emission peak at 686 nm(λ_(ex)665 nm). In the study,the possibility of MB as an extrinsic fluorophore to study the micellization behavior of bile salts(BSs) was carried out. Since BSs are drug delivery systems, the solubilization of hydrophobic MB drug molecule by BSs was achieved and the nature of association of MB with BS media, namely sodium cholate(Na C) and sodium deoxycholate(Na DC) was evaluated. Change in the photophysical properties of MB is monitored through fluorescence intensity and fluorescence anisotropy at emission peak, 686 nm of MB. Molecular mechanics calculations were carried out to evaluate the MB–BS association. The estimated heat of formation, ΔH_f values are –625.19 kcal/mol for MB–Na C and –757.48 kcal/mol for MB–Na DC. The photophysical study also revealed that MB reports the step-wise aggregation pattern of BSs media, as an extrinsic fluorescence probe.
文摘A hydrogel is formed by the self-assembly of sodium deoxycholate (NaDC) in aqueous solution with sodium chloride at pH-7.0. The NaDC hydrogel made of the three-dimensional network of nanofibers shows pH-dependent swelling behaviors. Polystyrene particles with a diameter of 100 nm and doxorubicin hydrochloride (DOX) can be easily loaded into the NaDC hydrogel through swelling. By using the loaded polystyrene particles as a light scattering probe, we study the microrheology of the NaDC hydrogel, showing complex viscoelastic properties. The viscous component dominates at both low and high frequencies, while the elastic component dominates in the intermediate range. The cavity size of the nanofiber network can also be estimated to be ~180 nm. We show that the loaded DOX can be slowly released from the hydrogels into aqueous solution. The release profile of DOX is found to depend on the pH value of the solution.
基金This research was supported grants of Arkansas Biosciences Institute,USDA National Institute of Food and Agriculture(NIFA)Hatch project 1012366USDA NIFA Hatch/Multi State project 1018699,USDA NIFA project 2018–06686 to X.
文摘Background:Clostridium perfringens-induced chicken necrotic enteritis(NE)is responsible for substantial economic losses worldwide annually.Recently,as a result of antibiotic growth promoter prohibition,the prevalence of NE in chickens has reemerged.This study was aimed to reduce NE through titrating dietary deoxycholic acid(DCA)as an effective antimicrobial alternative.Materials and methods:Day-old broiler chicks were assigned to six groups and fed diets supplemented with 0(basal diet),0.8,1.0 and 1.5 g/kg(on top of basal diet)DCA.The birds were challenged with Eimeria maxima(20,000 oocysts/bird)at d 18 and C.perfringens(109 CFU/bird per day)at d 23,24,and 25 to induce NE.The birds were sacrificed at d 26 when ileal tissue and digesta were collected for analyzing histopathology,mRNA accumulation and C.perfringens colonization by real-time PCR,targeted metabolomics of bile acids,fluorescence in situ hybridization(FISH),or terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assay.Results:At the cellular level,birds infected with E.maxima and C.perfringens developed subclinical NE and showed shortening villi,crypt hyperplasia and immune cell infiltration in ileum.Dietary DCA alleviated the NE-induced ileal inflammation in a dose-dependent manner compared to NE control birds.Consistent with the increased histopathological scores,subclinical NE birds suffered body weight gain reduction compared to the uninfected birds,an effect attenuated with increased doses of dietary DCA.At the molecular level,the highest dose of DCA at 1.5 g/kg reduced C.perfringens luminal colonization compared to NE birds using PCR and FISH.Furthermore,the dietary DCA reduced subclinical NE-induced intestinal inflammatory gene expression and cell apoptosis using PCR and TUNEL assays.Upon further examining ileal bile acid pool through targeted metabolomics,subclinical NE reduced the total bile acid level in ileal digesta compared to uninfected birds.Notably,dietary DCA increased total bile acid and DCA levels in a dose-dependent manner compared to NE birds.Conclusion:These results indicate that DCA attenuates NE-induced intestinal inflammation and bile acid reduction and could be an effective antimicrobial alternative against the intestinal disease.
基金We are very grateful to the National Natural Science Foundation of China(project:No.29772024)for the financial support.
文摘A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms. Instead of using toxic phosgene, the triphosgene was employed in synthesis of the molecular tweezers receptors. These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.
基金supported by the National Key Research and Development Program of China(2019YFA0906400)the National First-class Discipline Program of Light Industry Technology and Engineering(LITE2018-08)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_2486)We thank Prof.Shengying Li(Shandong University,China)for providing plasmids pET28a-SelFdx1499 and pET28a-SelFdR0978.
文摘Deoxycholic acid(DCA)has been authorized by the Federal Drug Agency for cosmetic reduction of redundant submental fat.The hydroxylated product(6β-OH DCA)was developed to improve the solubility and pharmaceutic properties of DCA for further applications.Herein,a combinatorial catalytic strategy was applied to construct a powerful Cytochrome P450 biocatalyst(CYP107D1,OleP)to convert DCA to 6β-OH DCA.Firstly,the weak expression of OleP was significantly improved using pRSFDuet-1 plasmid in the E.coli C41(DE3)strain.Next,the supply of heme was enhanced by the moderate overexpression of crucial genes in the heme biosynthetic pathway.In addition,a new biosensor was developed to select the appropriate redox partner.Furthermore,a cost-effective whole-cell catalytic system was constructed,resulting in the highest reported conversion rate of 6β-OH DCA(from 4.8%to 99.1%).The combinatorial catalytic strategies applied in this study provide an efficient method to synthesize high-value-added hydroxylated compounds by P450s.
