There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas(Hemibarbus labeo)egg.From the outer to the inner of the cortex,the diameter of the cortical alveoli decreases gradually.We found a n...There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas(Hemibarbus labeo)egg.From the outer to the inner of the cortex,the diameter of the cortical alveoli decreases gradually.We found a new structure named solicitation speckle at the low latitude of the animal pole and near the micropylar apparatus between the ovum envelope and cell membrane in the zygote of fish.The solicitation speckle similar to type I cortical alveoli was very purple in H.E chromosome,and it had no obvious boundary with the ovum envelope and membrane.Moreover,no membrane around the solicitation speckle in TEM was found.In SEM,the solicitation speckle looked flocculent.During cortical reaction,the solicitation speckle played a very important function in arousing cortical reaction.Thirty-five seconds after fertilization,cortical alveoli began to break down near the low latitude of the animal pole.At the same time,the same thing happened near the micropylar apparatus before cortical reaction.Both starting points encountered and healed up at the vestibule of the micropylar apparatus.The cortical reaction that happened near the low latitude of the animal pole was another new pattern.The cortical reaction was divided into four parts that included latent period,developmental period,climactic period and declining period.In the latent period,no cortical alveoli were released.In the developmental period,a few cortical alveoli were released outside the cortex.In the climactic period,several cortical alveoli were inosculated into a big vesicle and released intensely.In the declining period,the type V cortical alveoli and the other remnant cortical alveoli were released.Five minutes after fertilization,cortical alveoli were released entirely in the animal pole.Five minutes after fertilization,all of the remnant cortical alveoli were released.This leads us to conclude that cortical reaction is induced by type I cortical alveoli,and the solicitation speckle is a volcanic chain reaction under water or the other lower osmotic pressure of fluids.The outer cortical reaction can accelerate the inner cortical reaction.While cortical alveoli releases in batches,the cell plasma membrane is reorganized over and over.No cortical alveoli were found below the micropylar tube where sperm enters the ovum,which suggests that the cortical reaction prevents polyspermy.展开更多
Background: The homeobox containing transcription factor Nanog plays crucial roles in embryonic development/proliferation and/or maintenance of spermatogonial stem cells(SSCs) via interacting with transcription factor...Background: The homeobox containing transcription factor Nanog plays crucial roles in embryonic development/proliferation and/or maintenance of spermatogonial stem cells(SSCs) via interacting with transcription factors such as Oct4 and Sox2 in mammals. However, knowledge of its exact mechanistic pathways remains unexploited. Very little is known about teleost Nanog. Information on the Nanog gene of farmed rohu carp(Labeo rohita) is lacking. We cloned and characterized the Nanog gene of rohu carp to understand the expression pattern in early developmental stages and also deduced the genomic organization including promoter elements.Results: Rohu Nanog(LrNanog) cDNA comprised an open reading frame of 1,161 nucleotides bearing a structural homeodomain; whereas, the genomic structure contained four exons and three introns suggesting that it is homologous to mammalian counterparts. Phylogenetical y, it was closely related to freshwater counterparts. Protein sequence(386 AA of42.65 kDa) comparison revealed its low similarity with other vertebrate counterparts except that of the conserved homeodomain. Tissue distribution analysis revealed the existence of LrNanog transcripts only in adult gonads. The heightened abundances in the ovary and proliferating spermatogonia suggested its participations in maternal inheritance and male germ cell development. The potentiating abundances from fertilized egg onwards peaking at blastula stage vis-à-vis decreasing levels from gastrula stage onwards demonstrated its role in embryonic stem cell development. We also provided evidence of its presence in SSCs by western blotting analysis. Further, the promoter region was characterized, predicting a basal core promoter and other consensus elements.Conclusion: The molecular characterization of LrNanog and its documented expression profiling at transcript and protein levels are indicative of its functional linkage with embryonic/spermatogonial stem cell maintenance. This is the first report of LrNanog genomic organization including its promoter sequence information with predicted regulatory elements of a large-bodied carp species. This will be useful for elucidating its mechanism expression in future. Nanog could be used as a potential biomarker for proliferating carp SSCs.展开更多
Unwarranted accumulation of halogenated compounds in the rivers and streams has in recent years emerged due to the widespread use agricultural pesticides. The presence of these halogenated compounds in the water does ...Unwarranted accumulation of halogenated compounds in the rivers and streams has in recent years emerged due to the widespread use agricultural pesticides. The presence of these halogenated compounds in the water does not only suppress the immune system of fish but adversely induce serious morbidity and mortality among cultured stocks. Importantly, gradual accumulation of these compounds in the system of cultured and wild freshwater fish species cultured in ponds and floating net-cages in dams and rivers, respectively, poses some risks to humans, the end users. In this study, we attempted to isolate bacteria from the gut of pond-reared rohu (Labeo rohita) in Myanmar, screened the isolated bacteria for dehalogenase gene using molecular technique and tested the ability of these bacteria to degrade halogenated compounds in vitro. The eight bacterial strains studied were identified as Enterobacter mori strain MK- 121001, Enterobacter cloacae strains MK121003, MK-121004, MK121010, Ralstonia solanacearum strain 121002, Acinetobacter baumannii strain MK121007, Chromobacterium violaceum strain MK121009 and Pantoea vagans strain 121011. Only three bacterial strains (MK121002, MK121007 and MK121009) were capable of degrading 2,2-dichloropropionic acid (2,2-DCP) as the sole carbon source up to a final substrate concentration of 20 mM. Their mean growth doubling time ranging from 6-23 hours with the maximum of chloride ion released of 85%. PCR amplifica- tion with oligonucleotide primers designed from group I dehalogenase revealed the presence of deha- logenase genes in all isolates suggesting dehalogenase gene in strains 121001, 121003, 121004, 121010 and 121011 were silenced. In contrast, group II dehalogenase primers did not show any PCR amplification. These results suggest that MK121002, MK121007 and MK121009 only encode a group I dehalogenase and its non-stereoselectivity is in agreement with previoulsly described group I haloacid dehalogenase. The partial gene sequences were blasted but no significant sequence identity was observed. Therefore, it suggest the 2-haloacid dehalogenase of MK121002, MK12-1007 and MK121009 might be a novel group I 2-haloacid dehalogenase. The results indicated a broad distribution of dehalogenation genes in many micro- bial genomes that harbor dehalogenase(s) due to the exposure of the microorganisms to the naturally occurring or man-made halogenated compounds in the environmental systems. So far, microorganisms capable of producing dehalogenases were mainly isolated from soil and scarcely from aquatic animals and their environments. To the authors’ knowledge, this is the first report on the isolation of dehalogenase-producing bacteria from the gut of pond-reared freshwater fish, Labeo rohita, in Myanmar.展开更多
The present work reports the length–weight relationships(LWR)and condition factor relationships for Labeo calbasu collected from Upstream(Matyari)Kotri barrage at,River Indus,Pakistan,because stock assessment helps t...The present work reports the length–weight relationships(LWR)and condition factor relationships for Labeo calbasu collected from Upstream(Matyari)Kotri barrage at,River Indus,Pakistan,because stock assessment helps the fisheries managers to conserve the commercially important fish.Morphological characters of fish as well as Length-weight relationship are an important tool for fishery management.The results of LWR(W=aLb),for L calbasu.Representing negative allometric growth pattern.LWRs and condition factor relationships were found significantly correlated.A total of 200 and 190 specimens from upstream and downstream were collected,respectively.The assessed values of length-weight correlation and condition factor were calculated as Kn=39.663(LeCren),and K=11.915(Fulton)for upstream and Kn=44.066 and K=13.872 for downstream.Length-weight was found with a strong correlation of n=2.892,a=0.0235 with r2=0.934 for upstream population then the downstream population.The results of this work would be beneficial for sustainable management as well as fishery managers.展开更多
Multi-strain probiotics provide the most dependable approaches to improve health,immune response,and disease resistance in farmed fishes.In the present study,we examined the effects of multi-species probiotics on the ...Multi-strain probiotics provide the most dependable approaches to improve health,immune response,and disease resistance in farmed fishes.In the present study,we examined the effects of multi-species probiotics on the survival,growth,immune response,and disease resistance of rohu(Labeo rohita)larvae.Newly hatched larvae from the day of first feeding(average weight of 0.003 g)were reared with multi-species probiotics having a combination of Bacillus subtilis(109 colony forming units(cfu)/mL)and Lactobacillus spp.(Lactobacillus plantarum,Lactobacillus buchneri-1011 cfu/mL)in water containing doses of 0(control-C),0.5 mL/L(treatment 1-T1),and 1.0 mL/L(treatment 2-T2)in triplicates for 90 days.After the experiment,a challenge test was performed to assess the fish's resistance to pathogenic Aeromonas veronii.Significantly higher survival was recorded in larvae of treated groups(87%in T2 and 79%in T1)compared to the control(62%).Significantly higher growth performance(weight gain and specific growth rate—SGR)was shown by the probiotic-treated larval groups compared to the control.Probiotic supplementation resulted in significantly higher counts of total viable colony(TVC)and lactic acid bacteria(LAB)in the intestine.Some immunological parameters(mucosal fold fattening,goblet cell abundance,expansion of lamina propria and enterocytes)of the gut were significantly better in probiotic-treated fish.The liver of treated fish showed irregular shape nuclei turning into regular shape and reducing spaces between the hepatic cells.Probiotic-treated fish had the highest post-challenge survival rate(90%)against A.veronii infection.The erythrocytes of challenged fish treated with probiotics had significantly lower frequencies of various nuclear and cellular abnormalities.These findings suggest that multi-species probiotic supplements could improve the survival,growth,health status,and immune response of rohu in the early stages of its development.展开更多
采用人工催产和干法授精技术,在ZOOM645S解剖镜下对花(Hemibarbus maculatus)(♀)×唇(H.labeo)(♂)杂交子一代(F1)胚胎发育过程中各发育时期的发育时序和形态特征进行了观察。结果表明,受精卵为强黏性卵,卵径为1.60～1.80 mm。在...采用人工催产和干法授精技术,在ZOOM645S解剖镜下对花(Hemibarbus maculatus)(♀)×唇(H.labeo)(♂)杂交子一代(F1)胚胎发育过程中各发育时期的发育时序和形态特征进行了观察。结果表明,受精卵为强黏性卵,卵径为1.60～1.80 mm。在孵化水温为(20±1)℃条件下,受精后1 h胚盘隆起;1 h20 min进入卵裂期;6 h 20 min进入桑椹期;8 h 20 min进入囊胚期;13 h 10 min进入原肠期;16 h 20min进入神经胚期;受精后18 h进入胚孔封闭期;21 h 30 min进入肌节出现期;27 h 20 min进入眼基出现期;28 h 40 min进入眼囊期;30 h 40 min进入尾芽期;32 h 30 min进入晶体出现期;34 h 40 min进入肌肉效应期;36 h 40 min进入耳石出现期;44 h进入心跳期;53 h 40 min进入眼色素形成期;60 h 40min进入血液循环期;68 h 30 min后开始出膜。杂交F1胚胎发育时序及形态特征均偏向母本花。展开更多
基金This paper was supported by Chongqing Scien-tific Committee Project(No.2001-6630)Three Gorges Reservoir Area Environmental Key Laboratory of Ministry of Education Fund(No.03121).
文摘There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas(Hemibarbus labeo)egg.From the outer to the inner of the cortex,the diameter of the cortical alveoli decreases gradually.We found a new structure named solicitation speckle at the low latitude of the animal pole and near the micropylar apparatus between the ovum envelope and cell membrane in the zygote of fish.The solicitation speckle similar to type I cortical alveoli was very purple in H.E chromosome,and it had no obvious boundary with the ovum envelope and membrane.Moreover,no membrane around the solicitation speckle in TEM was found.In SEM,the solicitation speckle looked flocculent.During cortical reaction,the solicitation speckle played a very important function in arousing cortical reaction.Thirty-five seconds after fertilization,cortical alveoli began to break down near the low latitude of the animal pole.At the same time,the same thing happened near the micropylar apparatus before cortical reaction.Both starting points encountered and healed up at the vestibule of the micropylar apparatus.The cortical reaction that happened near the low latitude of the animal pole was another new pattern.The cortical reaction was divided into four parts that included latent period,developmental period,climactic period and declining period.In the latent period,no cortical alveoli were released.In the developmental period,a few cortical alveoli were released outside the cortex.In the climactic period,several cortical alveoli were inosculated into a big vesicle and released intensely.In the declining period,the type V cortical alveoli and the other remnant cortical alveoli were released.Five minutes after fertilization,cortical alveoli were released entirely in the animal pole.Five minutes after fertilization,all of the remnant cortical alveoli were released.This leads us to conclude that cortical reaction is induced by type I cortical alveoli,and the solicitation speckle is a volcanic chain reaction under water or the other lower osmotic pressure of fluids.The outer cortical reaction can accelerate the inner cortical reaction.While cortical alveoli releases in batches,the cell plasma membrane is reorganized over and over.No cortical alveoli were found below the micropylar tube where sperm enters the ovum,which suggests that the cortical reaction prevents polyspermy.
基金provided by grant from Indian Council of Agricultural Research (ICAR) and Department of Biotechnology(DBT),Government of India
文摘Background: The homeobox containing transcription factor Nanog plays crucial roles in embryonic development/proliferation and/or maintenance of spermatogonial stem cells(SSCs) via interacting with transcription factors such as Oct4 and Sox2 in mammals. However, knowledge of its exact mechanistic pathways remains unexploited. Very little is known about teleost Nanog. Information on the Nanog gene of farmed rohu carp(Labeo rohita) is lacking. We cloned and characterized the Nanog gene of rohu carp to understand the expression pattern in early developmental stages and also deduced the genomic organization including promoter elements.Results: Rohu Nanog(LrNanog) cDNA comprised an open reading frame of 1,161 nucleotides bearing a structural homeodomain; whereas, the genomic structure contained four exons and three introns suggesting that it is homologous to mammalian counterparts. Phylogenetical y, it was closely related to freshwater counterparts. Protein sequence(386 AA of42.65 kDa) comparison revealed its low similarity with other vertebrate counterparts except that of the conserved homeodomain. Tissue distribution analysis revealed the existence of LrNanog transcripts only in adult gonads. The heightened abundances in the ovary and proliferating spermatogonia suggested its participations in maternal inheritance and male germ cell development. The potentiating abundances from fertilized egg onwards peaking at blastula stage vis-à-vis decreasing levels from gastrula stage onwards demonstrated its role in embryonic stem cell development. We also provided evidence of its presence in SSCs by western blotting analysis. Further, the promoter region was characterized, predicting a basal core promoter and other consensus elements.Conclusion: The molecular characterization of LrNanog and its documented expression profiling at transcript and protein levels are indicative of its functional linkage with embryonic/spermatogonial stem cell maintenance. This is the first report of LrNanog genomic organization including its promoter sequence information with predicted regulatory elements of a large-bodied carp species. This will be useful for elucidating its mechanism expression in future. Nanog could be used as a potential biomarker for proliferating carp SSCs.
文摘Unwarranted accumulation of halogenated compounds in the rivers and streams has in recent years emerged due to the widespread use agricultural pesticides. The presence of these halogenated compounds in the water does not only suppress the immune system of fish but adversely induce serious morbidity and mortality among cultured stocks. Importantly, gradual accumulation of these compounds in the system of cultured and wild freshwater fish species cultured in ponds and floating net-cages in dams and rivers, respectively, poses some risks to humans, the end users. In this study, we attempted to isolate bacteria from the gut of pond-reared rohu (Labeo rohita) in Myanmar, screened the isolated bacteria for dehalogenase gene using molecular technique and tested the ability of these bacteria to degrade halogenated compounds in vitro. The eight bacterial strains studied were identified as Enterobacter mori strain MK- 121001, Enterobacter cloacae strains MK121003, MK-121004, MK121010, Ralstonia solanacearum strain 121002, Acinetobacter baumannii strain MK121007, Chromobacterium violaceum strain MK121009 and Pantoea vagans strain 121011. Only three bacterial strains (MK121002, MK121007 and MK121009) were capable of degrading 2,2-dichloropropionic acid (2,2-DCP) as the sole carbon source up to a final substrate concentration of 20 mM. Their mean growth doubling time ranging from 6-23 hours with the maximum of chloride ion released of 85%. PCR amplifica- tion with oligonucleotide primers designed from group I dehalogenase revealed the presence of deha- logenase genes in all isolates suggesting dehalogenase gene in strains 121001, 121003, 121004, 121010 and 121011 were silenced. In contrast, group II dehalogenase primers did not show any PCR amplification. These results suggest that MK121002, MK121007 and MK121009 only encode a group I dehalogenase and its non-stereoselectivity is in agreement with previoulsly described group I haloacid dehalogenase. The partial gene sequences were blasted but no significant sequence identity was observed. Therefore, it suggest the 2-haloacid dehalogenase of MK121002, MK12-1007 and MK121009 might be a novel group I 2-haloacid dehalogenase. The results indicated a broad distribution of dehalogenation genes in many micro- bial genomes that harbor dehalogenase(s) due to the exposure of the microorganisms to the naturally occurring or man-made halogenated compounds in the environmental systems. So far, microorganisms capable of producing dehalogenases were mainly isolated from soil and scarcely from aquatic animals and their environments. To the authors’ knowledge, this is the first report on the isolation of dehalogenase-producing bacteria from the gut of pond-reared freshwater fish, Labeo rohita, in Myanmar.
基金The present work is partial work of M.Phil research scholar.
文摘The present work reports the length–weight relationships(LWR)and condition factor relationships for Labeo calbasu collected from Upstream(Matyari)Kotri barrage at,River Indus,Pakistan,because stock assessment helps the fisheries managers to conserve the commercially important fish.Morphological characters of fish as well as Length-weight relationship are an important tool for fishery management.The results of LWR(W=aLb),for L calbasu.Representing negative allometric growth pattern.LWRs and condition factor relationships were found significantly correlated.A total of 200 and 190 specimens from upstream and downstream were collected,respectively.The assessed values of length-weight correlation and condition factor were calculated as Kn=39.663(LeCren),and K=11.915(Fulton)for upstream and Kn=44.066 and K=13.872 for downstream.Length-weight was found with a strong correlation of n=2.892,a=0.0235 with r2=0.934 for upstream population then the downstream population.The results of this work would be beneficial for sustainable management as well as fishery managers.
基金Krishi Gobeshona Foundation,Bangladesh Agricultural Research Council,Dhaka,supported a grant(CGP TF 75-F/20)the corresponding author.Bangladesh Agricultural University Research System(BAURES)is gratefully acknowledged for the financial management of this project(Project No.2020/954/KGF).
文摘Multi-strain probiotics provide the most dependable approaches to improve health,immune response,and disease resistance in farmed fishes.In the present study,we examined the effects of multi-species probiotics on the survival,growth,immune response,and disease resistance of rohu(Labeo rohita)larvae.Newly hatched larvae from the day of first feeding(average weight of 0.003 g)were reared with multi-species probiotics having a combination of Bacillus subtilis(109 colony forming units(cfu)/mL)and Lactobacillus spp.(Lactobacillus plantarum,Lactobacillus buchneri-1011 cfu/mL)in water containing doses of 0(control-C),0.5 mL/L(treatment 1-T1),and 1.0 mL/L(treatment 2-T2)in triplicates for 90 days.After the experiment,a challenge test was performed to assess the fish's resistance to pathogenic Aeromonas veronii.Significantly higher survival was recorded in larvae of treated groups(87%in T2 and 79%in T1)compared to the control(62%).Significantly higher growth performance(weight gain and specific growth rate—SGR)was shown by the probiotic-treated larval groups compared to the control.Probiotic supplementation resulted in significantly higher counts of total viable colony(TVC)and lactic acid bacteria(LAB)in the intestine.Some immunological parameters(mucosal fold fattening,goblet cell abundance,expansion of lamina propria and enterocytes)of the gut were significantly better in probiotic-treated fish.The liver of treated fish showed irregular shape nuclei turning into regular shape and reducing spaces between the hepatic cells.Probiotic-treated fish had the highest post-challenge survival rate(90%)against A.veronii infection.The erythrocytes of challenged fish treated with probiotics had significantly lower frequencies of various nuclear and cellular abnormalities.These findings suggest that multi-species probiotic supplements could improve the survival,growth,health status,and immune response of rohu in the early stages of its development.
文摘采用人工催产和干法授精技术,在ZOOM645S解剖镜下对花(Hemibarbus maculatus)(♀)×唇(H.labeo)(♂)杂交子一代(F1)胚胎发育过程中各发育时期的发育时序和形态特征进行了观察。结果表明,受精卵为强黏性卵,卵径为1.60～1.80 mm。在孵化水温为(20±1)℃条件下,受精后1 h胚盘隆起;1 h20 min进入卵裂期;6 h 20 min进入桑椹期;8 h 20 min进入囊胚期;13 h 10 min进入原肠期;16 h 20min进入神经胚期;受精后18 h进入胚孔封闭期;21 h 30 min进入肌节出现期;27 h 20 min进入眼基出现期;28 h 40 min进入眼囊期;30 h 40 min进入尾芽期;32 h 30 min进入晶体出现期;34 h 40 min进入肌肉效应期;36 h 40 min进入耳石出现期;44 h进入心跳期;53 h 40 min进入眼色素形成期;60 h 40min进入血液循环期;68 h 30 min后开始出膜。杂交F1胚胎发育时序及形态特征均偏向母本花。
