The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped ph...The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped phase larvae (24 h), early umbo phase larvae, umbo phase larvae, post um- bo phase larvae and eyespot phase larvae] in the Luhuitou Pearl Oyster Mariculture Farm of Sanya City, Hainan Province in April 1995 showed that there were two peaks of mortality rates which occurred in early umbo phase or umbo phase and post umbo phase (Figs 3-5 and Table 1) respectively from pre- embryonic developmental periods to larvae phases. It indicated that the onset and death of Pinctada maxima larvae populations followed a pattem of outbreak. Between the prevalence, intensity of RLO infection and the mortality rates of larvae populations were of obvious positively correlations. Generally, every peak of RLO infection is always follwed by a peak of mortality rate of larvae hosts, and the mor- tality rates of larvae hosts declined with the decreased RLO infection (see Figs 3-5 ). Under the trans- mission electron microscopy (TEM), no rickettsia-like organisms were discovered in oocytes, fertilized ovum and early embryonic phase larvae (6 h). The RLO inclusions occurred first in the D-shaped phase larvae (24 h) under histological examination. Absences of RLO in transmission electron exami- nation of oocytes of RLO-infected adult females, ferilized ovum and early embryonic phase larvae (6 h) indicated that RLO may not be transmitted transovarially. But RLO for host infection may be trans- mitted by contact transmission since RLO inclusions were first identified regularly in D-shaped phase larvae (24 h), while these D-shaped phase larvae were still unable to take food during hatching 24 hours. In addition, the result of epidemiological investigation showed that no odservable death occurred in D-shaped larvae populations, but early obvious death occurred in larvae populations in the seventh day after fertilization, in a rate of about 21. 8%. It indicated that there was a incubation peried from RLO infection for host (D-shaped phase larvae) to host onset and death occurred clinically.展开更多
The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study and statistic analyses, the epidemio...The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study and statistic analyses, the epidemiological study was carried out on the disease and death in juvenile populations of Pinctada maxima in the Xinying Pearl Oyster Mariculture Farm of Lingao County (for the A, B and C batches of cultured juveniles hanged in the sea) and the Xincun Pearl Oyster Mariculture Farm of Lingshui County (for the D batch of cultured juvenile hanged in the pond), Hainan Province from November 1993 to April 1995.The results show that the deaths which occurred in juvenile populations of Pinctada maxima presented an outbreak pattern. The peak of mortality rates, in general, occurred in 4-to 6-month old pearl oyster juveniles, and the mortality rates gradully declined with the extention of pearl oyster age after cul-turing 8 months. The correlation between the mortality rates of juvenile populations and mean body lengths of juvenile populations show that the mortality rate become higher under 4 cm of mean body lengths of juvenile population and become obvious declined over 5 cm of mean body lengths. The peak of mortality rate occurred in 1-3 cm of mean body lengths. The results of histological observation showed that rickettsia-like organism inclusions were common, histological widespread infective agent among every batches (A, B, C and D) of cultured juvenile populations. The mean severity indices (SI) of rickettsia-like organism (RLO) infection were positively correlated with mortality rates of juvenile populations. After or within every peaks of RLO infection were all accompanied with the peaks of mortality rates of host populations and the mortality rates declined with decreased RLO infection. So the evidences of histological observation and epidemiology in this study indicated that rickettsia-like organism (RLO) may be as an important pathogenic organism of disease and death of cultured Pinctada maxima. In addition, a few ciliates were discovered only in part of batch A of cultured juvenile population. The mortality rates in juvenile populations were not correlated with the weekly mean temperature and salinity of sea water.展开更多
Pearl oyster Pinctada maxima is mainly used to produce high-valued gold and silver colored nucleated pearls.We developed a line with golden nacre in the mantle edge by sampling breeders from the Sanya population of pe...Pearl oyster Pinctada maxima is mainly used to produce high-valued gold and silver colored nucleated pearls.We developed a line with golden nacre in the mantle edge by sampling breeders from the Sanya population of pearl oyster P.maxima.It is found that the total carotenoid content(TCC)in the mantle tissues of the strain group(SG)was significantly higher than that of the control group(CG).Differentially expressed genes between the strain and control group(a line with silver nacre in the mantle edge)were screened.A total of 28285 genes were annotated in the transcriptome.Totally,295 up-regulated genes and 254 down-regulated genes were annotated which the strain compared with the CG.Lipid-transport and metabolism genes,such as fatty acid-binding protein,cytochrome P4503A and ATP-binding cassette sub-family A were up-regulated in the line.The expression levels of candidate genes in the line were higher than those in the CG,which are basically consistent with the transcriptome results.These findings are helpful to understand carotenoid metabolism in golden colored nacre formation of pearl oyster P.maxima.展开更多
The dry ligament of Pinctada maxima normally appears black;however,it can exhibit striking blue structural colors after being wetted by water.The field-mission SEM investigation shows that the liga- ment is made of la...The dry ligament of Pinctada maxima normally appears black;however,it can exhibit striking blue structural colors after being wetted by water.The field-mission SEM investigation shows that the liga- ment is made of lamellae,which,about 35μm thick,are made of proteins and aragonite fibers of about 78 nm in diameter.In each single lamella,the fibers are highly aligned characterized by a 2D photonic crystal type structure.According to measured reflective spectra and theoretical simulations,the dry and wet ligaments possess photonic stop band at ultraviolet and blue wavelengths,respectively,which are responsible for structural colorations of ligament.展开更多
基金This study was supported by the Projects under the Major State Basic Research Development Program under contractNo.G199012001,
文摘The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped phase larvae (24 h), early umbo phase larvae, umbo phase larvae, post um- bo phase larvae and eyespot phase larvae] in the Luhuitou Pearl Oyster Mariculture Farm of Sanya City, Hainan Province in April 1995 showed that there were two peaks of mortality rates which occurred in early umbo phase or umbo phase and post umbo phase (Figs 3-5 and Table 1) respectively from pre- embryonic developmental periods to larvae phases. It indicated that the onset and death of Pinctada maxima larvae populations followed a pattem of outbreak. Between the prevalence, intensity of RLO infection and the mortality rates of larvae populations were of obvious positively correlations. Generally, every peak of RLO infection is always follwed by a peak of mortality rate of larvae hosts, and the mor- tality rates of larvae hosts declined with the decreased RLO infection (see Figs 3-5 ). Under the trans- mission electron microscopy (TEM), no rickettsia-like organisms were discovered in oocytes, fertilized ovum and early embryonic phase larvae (6 h). The RLO inclusions occurred first in the D-shaped phase larvae (24 h) under histological examination. Absences of RLO in transmission electron exami- nation of oocytes of RLO-infected adult females, ferilized ovum and early embryonic phase larvae (6 h) indicated that RLO may not be transmitted transovarially. But RLO for host infection may be trans- mitted by contact transmission since RLO inclusions were first identified regularly in D-shaped phase larvae (24 h), while these D-shaped phase larvae were still unable to take food during hatching 24 hours. In addition, the result of epidemiological investigation showed that no odservable death occurred in D-shaped larvae populations, but early obvious death occurred in larvae populations in the seventh day after fertilization, in a rate of about 21. 8%. It indicated that there was a incubation peried from RLO infection for host (D-shaped phase larvae) to host onset and death occurred clinically.
基金Major State Basic Research Development Program of China under contract No. G1999012001Key Science Foundation of the Chinese Academy of Sciences contract KS85-121.
文摘The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study and statistic analyses, the epidemiological study was carried out on the disease and death in juvenile populations of Pinctada maxima in the Xinying Pearl Oyster Mariculture Farm of Lingao County (for the A, B and C batches of cultured juveniles hanged in the sea) and the Xincun Pearl Oyster Mariculture Farm of Lingshui County (for the D batch of cultured juvenile hanged in the pond), Hainan Province from November 1993 to April 1995.The results show that the deaths which occurred in juvenile populations of Pinctada maxima presented an outbreak pattern. The peak of mortality rates, in general, occurred in 4-to 6-month old pearl oyster juveniles, and the mortality rates gradully declined with the extention of pearl oyster age after cul-turing 8 months. The correlation between the mortality rates of juvenile populations and mean body lengths of juvenile populations show that the mortality rate become higher under 4 cm of mean body lengths of juvenile population and become obvious declined over 5 cm of mean body lengths. The peak of mortality rate occurred in 1-3 cm of mean body lengths. The results of histological observation showed that rickettsia-like organism inclusions were common, histological widespread infective agent among every batches (A, B, C and D) of cultured juvenile populations. The mean severity indices (SI) of rickettsia-like organism (RLO) infection were positively correlated with mortality rates of juvenile populations. After or within every peaks of RLO infection were all accompanied with the peaks of mortality rates of host populations and the mortality rates declined with decreased RLO infection. So the evidences of histological observation and epidemiology in this study indicated that rickettsia-like organism (RLO) may be as an important pathogenic organism of disease and death of cultured Pinctada maxima. In addition, a few ciliates were discovered only in part of batch A of cultured juvenile population. The mortality rates in juvenile populations were not correlated with the weekly mean temperature and salinity of sea water.
基金supported by Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams,Department of Agriculture and Rural Affairs of Guangdong Province(Grant No.2020KJ146)Special promotion of fishery science and technology of Ocean and Fisheries Bureau of Guangdong Province(Grant No.Z2014011 and Z2015002)+1 种基金"Innovation Team Project"special funds(Grant No.2017KCXTD016)from the Department of Education of Guangdong ProvinceModern Agricultural Industrial System(Grant No.CARS-049).
文摘Pearl oyster Pinctada maxima is mainly used to produce high-valued gold and silver colored nucleated pearls.We developed a line with golden nacre in the mantle edge by sampling breeders from the Sanya population of pearl oyster P.maxima.It is found that the total carotenoid content(TCC)in the mantle tissues of the strain group(SG)was significantly higher than that of the control group(CG).Differentially expressed genes between the strain and control group(a line with silver nacre in the mantle edge)were screened.A total of 28285 genes were annotated in the transcriptome.Totally,295 up-regulated genes and 254 down-regulated genes were annotated which the strain compared with the CG.Lipid-transport and metabolism genes,such as fatty acid-binding protein,cytochrome P4503A and ATP-binding cassette sub-family A were up-regulated in the line.The expression levels of candidate genes in the line were higher than those in the CG,which are basically consistent with the transcriptome results.These findings are helpful to understand carotenoid metabolism in golden colored nacre formation of pearl oyster P.maxima.
基金Supported by the Guangxi Education Department(Grant No.2004-20)
文摘The dry ligament of Pinctada maxima normally appears black;however,it can exhibit striking blue structural colors after being wetted by water.The field-mission SEM investigation shows that the liga- ment is made of lamellae,which,about 35μm thick,are made of proteins and aragonite fibers of about 78 nm in diameter.In each single lamella,the fibers are highly aligned characterized by a 2D photonic crystal type structure.According to measured reflective spectra and theoretical simulations,the dry and wet ligaments possess photonic stop band at ultraviolet and blue wavelengths,respectively,which are responsible for structural colorations of ligament.
