The ultrastructure of oogenesis of Bullacta exarata was studied with transmission electron microscope.The result showed that the oogenesis of Bullacta exarata could be divided into four stages,for example,oogo...The ultrastructure of oogenesis of Bullacta exarata was studied with transmission electron microscope.The result showed that the oogenesis of Bullacta exarata could be divided into four stages,for example,oogonium,early vitellogenic oocyte,mid vitellogenic oocyte and end vitellogenic oocyte.Besides a large and round nucleus,oogonium mainly contains mitochondria,sacs of golgi and microvillie appears in this stage.At the early stage of vitellogenesis,the organelles are developed,and a great deal of nuages like materials appear in oocyte cytoplasm.At the mid stage of vitellogenesis,the nucleus forms pseudopodia liked extension.The organelles including mitochondria,golgi complex and endoplasmic reticulum are well developed,and lots of yolk granule and lipid droplet are formed in the cytoplasm.The exchange of material between oocytes and follicle cells is intense in this stage.At the end stage of vitellogenesis,the oocytes contain fewer numbers of the organelles.The changes of structure and significance in oocytes,and the exchange of material between oocytes and follicle cells are also discussed.展开更多
The morphology and ultrastructure of Bullacta exarata spermatozoa observed by light and transmission electron microscopy are presented in this paper. The spermatozoon is composed of head with a simple acrosomal comple...The morphology and ultrastructure of Bullacta exarata spermatozoa observed by light and transmission electron microscopy are presented in this paper. The spermatozoon is composed of head with a simple acrosomal complex and an elongated nucleus, and tail with a midpiece, principal piece and an end piece. The midpiece consists of a mitochondrial ring, and the principal piece is composed of axoneme and lateral fin. The structure of 5. exarata spermatozoa differs significantly from that of other gastropods, especially in the lateral fin and the principal piece, which was described scarcely before. A comparison is made between B. exarata and other gastropods, and its significance on reproductive evolution and physio-ecological adaptation is preliminarily discussed.展开更多
The bacterial flora in the digestive tract of B. exarata Philippi and its rearing shoal were investigated, respectively. A total of 107 strains of heterotrophic bacteria, isolated from crop, stomach and intestine, mai...The bacterial flora in the digestive tract of B. exarata Philippi and its rearing shoal were investigated, respectively. A total of 107 strains of heterotrophic bacteria, isolated from crop, stomach and intestine, mainly belong to genera Photobacterium, Bacillus, Pseudomonas and Vibrio. Varieties of bacteria in crop were significantly more than that in stomach and in intestine. A total of 173 strains of bacteria were isolated from the rearing shoal, belonging to 13 genera. The 5 predominant genera are Photobacterium, Bacillus, Pseudomonas, Vibrio and some genera of Enterobacteriaceae. The number of heterotrophic bacteria and Vibrio in rearing shoal changed in line with the alteration of the temperature, and were significantly affected by the use of pesticide.展开更多
The bacterial flora in the digestive tube of Bullacta exarata Philippi and its rearing shoal were investigated. A total of 157 strains of heterotrophic bacteria, isolated from crop, stomach intestine and other parts o...The bacterial flora in the digestive tube of Bullacta exarata Philippi and its rearing shoal were investigated. A total of 157 strains of heterotrophic bacteria, isolated from crop, stomach intestine and other parts of the digestive tube, mainly belong to the genera Photobacterium, Bacillus, Pseudomonas Vibrio and some genera of the family Enterobacteriaceae. There are significantly more varieties of bacteria in crop than in stomach and intestine. A total of 173 strains of bacteria were isolated from the rearing shoal, belonging to 13 genera. The 5 predominant genera, such as Bacillus and Photobacterium, are the same as those in the digestive tube, but greatly differ in percentages. The number of heterotrophic bacteria and Vibrio in rearing shoal change in line with the alteration of the temperature, and are significantly affected by the use of pesticides.展开更多
Since the mud snail Bullacta exarata was introduced for economic aquaculture in the Huanghe River(Yellow River) Delta in 2001, its quick population growth and expanded distribution make it a key-species in the interti...Since the mud snail Bullacta exarata was introduced for economic aquaculture in the Huanghe River(Yellow River) Delta in 2001, its quick population growth and expanded distribution make it a key-species in the intertidal zone of this area. This significantly contributed to the economic income of the local people, but its potential ecological impact on the benthic ecosystem remains unknown. A mesocosm study was conducted to test whether its bioturbation activities affect the microphytobenthos(MPBs;i.e., sedimentary microbes and unicellular algae)productivity and the nutrient exchange between the sediment-water interface. Our results show that the mud snail significantly impacted the dissolved oxygen(DO) flux across the sediment-water interface on the condition of normal sediment and light treatment, and significantly increased the ammonium efflux during recovery period in the defaunated sediment and dark treatment. The presence of micro-and meiofauna significantly increased the NH4-N flux in dark treatment. Whereas, in light treatment, these small animals had less effects on the DO and NH4-N flux between sediment-water interface. Our results provide better insight into the effect of the mud snail B.exarata on the ecosystem functioning via benthic fluxes.展开更多
The number of heterotrophic bacteria and vibrios in shoal for Bullacta exarata rearing fluctuated mainly within 1.25×10 4～7.21×10 4 cfu·g -1 and 0～1.08×10 4 cfu·g -1 ,respectively. 173 strai...The number of heterotrophic bacteria and vibrios in shoal for Bullacta exarata rearing fluctuated mainly within 1.25×10 4～7.21×10 4 cfu·g -1 and 0～1.08×10 4 cfu·g -1 ,respectively. 173 strains of bacteria, mainly belong to 13 genera were isolated. The predominant genera were composed of Bacillus,Photobacterium,Pseudomonas,Vibrio and some genera of Enterobacteriaceae . The number of bacteria changed in line with the alteration of the temperature,and was especially affected by the organic matter content after the use of pesticide. The predominant genera such as Bacillus were closely related with the environmental deterioration of rearing shoal.展开更多
文摘The ultrastructure of oogenesis of Bullacta exarata was studied with transmission electron microscope.The result showed that the oogenesis of Bullacta exarata could be divided into four stages,for example,oogonium,early vitellogenic oocyte,mid vitellogenic oocyte and end vitellogenic oocyte.Besides a large and round nucleus,oogonium mainly contains mitochondria,sacs of golgi and microvillie appears in this stage.At the early stage of vitellogenesis,the organelles are developed,and a great deal of nuages like materials appear in oocyte cytoplasm.At the mid stage of vitellogenesis,the nucleus forms pseudopodia liked extension.The organelles including mitochondria,golgi complex and endoplasmic reticulum are well developed,and lots of yolk granule and lipid droplet are formed in the cytoplasm.The exchange of material between oocytes and follicle cells is intense in this stage.At the end stage of vitellogenesis,the oocytes contain fewer numbers of the organelles.The changes of structure and significance in oocytes,and the exchange of material between oocytes and follicle cells are also discussed.
文摘The morphology and ultrastructure of Bullacta exarata spermatozoa observed by light and transmission electron microscopy are presented in this paper. The spermatozoon is composed of head with a simple acrosomal complex and an elongated nucleus, and tail with a midpiece, principal piece and an end piece. The midpiece consists of a mitochondrial ring, and the principal piece is composed of axoneme and lateral fin. The structure of 5. exarata spermatozoa differs significantly from that of other gastropods, especially in the lateral fin and the principal piece, which was described scarcely before. A comparison is made between B. exarata and other gastropods, and its significance on reproductive evolution and physio-ecological adaptation is preliminarily discussed.
文摘The bacterial flora in the digestive tract of B. exarata Philippi and its rearing shoal were investigated, respectively. A total of 107 strains of heterotrophic bacteria, isolated from crop, stomach and intestine, mainly belong to genera Photobacterium, Bacillus, Pseudomonas and Vibrio. Varieties of bacteria in crop were significantly more than that in stomach and in intestine. A total of 173 strains of bacteria were isolated from the rearing shoal, belonging to 13 genera. The 5 predominant genera are Photobacterium, Bacillus, Pseudomonas, Vibrio and some genera of Enterobacteriaceae. The number of heterotrophic bacteria and Vibrio in rearing shoal changed in line with the alteration of the temperature, and were significantly affected by the use of pesticide.
文摘The bacterial flora in the digestive tube of Bullacta exarata Philippi and its rearing shoal were investigated. A total of 157 strains of heterotrophic bacteria, isolated from crop, stomach intestine and other parts of the digestive tube, mainly belong to the genera Photobacterium, Bacillus, Pseudomonas Vibrio and some genera of the family Enterobacteriaceae. There are significantly more varieties of bacteria in crop than in stomach and intestine. A total of 173 strains of bacteria were isolated from the rearing shoal, belonging to 13 genera. The 5 predominant genera, such as Bacillus and Photobacterium, are the same as those in the digestive tube, but greatly differ in percentages. The number of heterotrophic bacteria and Vibrio in rearing shoal change in line with the alteration of the temperature, and are significantly affected by the use of pesticides.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences under contract Nos XDA23050304 and XDA23050202the Key Research Project of Frontier Science of Chinese Academy of Sciences under contract No.QYZDB-SSWDQC041+3 种基金the Program of Ministry of Science and Technology of the People’s Republic of China under contract No.2015FY210300the National Natural Science Foundation of China under contract No.41061130543the Netherlands Organization for Scientific Research under contract No.843.10.003 as part of the NSFC-NOW “Water ways,Harbours,Estuaries and Coastal Engineering” schemethe self-deployment project of Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences under contract No.YIC755021012
文摘Since the mud snail Bullacta exarata was introduced for economic aquaculture in the Huanghe River(Yellow River) Delta in 2001, its quick population growth and expanded distribution make it a key-species in the intertidal zone of this area. This significantly contributed to the economic income of the local people, but its potential ecological impact on the benthic ecosystem remains unknown. A mesocosm study was conducted to test whether its bioturbation activities affect the microphytobenthos(MPBs;i.e., sedimentary microbes and unicellular algae)productivity and the nutrient exchange between the sediment-water interface. Our results show that the mud snail significantly impacted the dissolved oxygen(DO) flux across the sediment-water interface on the condition of normal sediment and light treatment, and significantly increased the ammonium efflux during recovery period in the defaunated sediment and dark treatment. The presence of micro-and meiofauna significantly increased the NH4-N flux in dark treatment. Whereas, in light treatment, these small animals had less effects on the DO and NH4-N flux between sediment-water interface. Our results provide better insight into the effect of the mud snail B.exarata on the ecosystem functioning via benthic fluxes.
文摘The number of heterotrophic bacteria and vibrios in shoal for Bullacta exarata rearing fluctuated mainly within 1.25×10 4～7.21×10 4 cfu·g -1 and 0～1.08×10 4 cfu·g -1 ,respectively. 173 strains of bacteria, mainly belong to 13 genera were isolated. The predominant genera were composed of Bacillus,Photobacterium,Pseudomonas,Vibrio and some genera of Enterobacteriaceae . The number of bacteria changed in line with the alteration of the temperature,and was especially affected by the organic matter content after the use of pesticide. The predominant genera such as Bacillus were closely related with the environmental deterioration of rearing shoal.
