scholarly journals ​Isolation and Characterization of a Vibrio Sp. Strain MA3 Possibly Associated with Mass Mortalities of the Pearl Oyster Pinctada fucata

Author(s):  
Akihiro SAKATOKU ◽  
Kaito Hatano ◽  
Shoki Tanaka ◽  
Tadashi Isshiki

Abstract In the summers of 2019 and 2020, a previously undescribed disease occurred in both juvenile and adult shellfish, causing mass mortalities in cultured pearl production, characterized by the major symptom of extreme atrophy of the soft tissues, including the mantle. However, the causative organism was uncertain. We isolated Vibrio sp. strain MA3 from the mantles of diseased pearl oysters Pinctada fucata. Analyses of 16S rRNA gene and DNA gyrase sequence homologies and its biochemical and morphological characteristics suggested that strain MA3 is a new strain of Vibrio alginolyticus. In addition, a hemolysin gene (Vhe1) of strain MA3 was detected as one of the virulence factors, and the complete sequence was determined. BLAST searches showed that Vhe1 shares 99.8% nucleotide sequence identity with Vibrio alginolyticus strain A056 lecithin-dependent hemolysin (ldh) gene, complete cds. Experimental infection of healthy oysters via injection with strain MA3 indicated it could cause high mortalities of the typically affected oysters from which the strain was isolated. These results suggest that the newly isolated Vibrio sp. strain MA3 is a putative causal agent of the recent disease outbreaks in Akoya pearl oysters.

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12180
Author(s):  
Tomomasa Matsuyama ◽  
Satoshi Miwa ◽  
Tohru Mekata ◽  
Yuta Matsuura ◽  
Tomokazu Takano ◽  
...  

Mass mortality of 0-year-old pearl oysters, Pinctada fucata (Gould), and anomalies in adults were observed in Japan’s major pearl farming areas in the summer of 2019 and 2020. Although adult oyster mortality was low, both adult and juvenile oysters underwent atrophy of the soft body, detachment of the mantle from nacre (the shiny inner surface of the valves), deposition of brownish material on the nacre, and loss of nacre luster. Infection trials were conducted to verify the involvement of pathogens in this phenomenon. Healthy adult pearl oysters were obtained from areas where this disease had not occurred to use as the recipients. The sources of infection were either affected adult oysters with atrophied soft bodies or batches of juveniles in which mortality had reached conspicuous levels. Transmission of the disease to the healthy oysters were tested either by cohabitation with affected oysters or by injections of the hemolymph of affected animals. The injection infection test examined the effects of filtration and chloroform exposure on the pathogen. Occurrence of the disease was confirmed by the appearance of brown deposits on the nacre and loss of nacre luster. The abnormalities of nacre were clearly reproduced in recipient shells in three out of four cohabitation trials with affected oysters. The disease was also reproduced in six out of six injection trails either with hemolymph filtered through 100 nm filter or with hemolymph treated with chloroform. In a serial passage with hemolymph injections, the disease was successfully transmitted through eight passages. These results suggest that the etiology of the disease is a non-enveloped virus with a diameter ≤100 nm.


2016 ◽  
Vol 55 ◽  
pp. 585-594 ◽  
Author(s):  
Zhongliang Wang ◽  
Bei Wang ◽  
Gang Chen ◽  
Yishan Lu ◽  
Jichang Jian ◽  
...  

2017 ◽  
Vol 39 (10) ◽  
pp. 1069-1081 ◽  
Author(s):  
Zhongliang Wang ◽  
Bei Wang ◽  
Gang Chen ◽  
Yishan Lu ◽  
Jichang Jian ◽  
...  

2005 ◽  
Vol 71 (1) ◽  
pp. 98-104 ◽  
Author(s):  
J. G�mez-Le�n ◽  
L. Villamil ◽  
M. L. Lemos ◽  
B. Novoa ◽  
A. Figueras

ABSTRACT Two episodes of mortality of cultured carpet shell clams (Ruditapes decussatus) associated with bacterial infections were recorded during 2001 and 2002 in a commercial hatchery located in Spain. Vibrio alginolyticus was isolated as the primary organism from moribund clam larvae that were obtained during the two separate events. Vibrio splendidus biovar II, in addition to V. alginolyticus, was isolated as a result of a mixed Vibrio infection from moribund clam larvae obtained from the second mortality event. The larval mortality rates for these events were 62 and 73%, respectively. Mortality was also detected in spat. To our knowledge, this is the fist time that these bacterial species have been associated with larval and juvenile carpet shell clam mortality. The bacterial strains were identified by morphological and biochemical techniques and also by PCR and sequencing of a conserved region of the 16S rRNA gene. In both cases bacteria isolated in pure culture were inoculated into spat of carpet shell clams by intravalvar injection and by immersion. The mortality was attributed to the inoculated strains, since the bacteria were obtained in pure culture from the soft tissues of experimentally infected clams. V. alginolyticus TA15 and V. splendidus biovar II strain TA2 caused similar histological lesions that affected mainly the mantle, the velum, and the connective tissue of infected organisms. The general enzymatic activity of both live cells and extracellular products (ECPs), as evaluated by the API ZYM system, revealed that whole bacterial cells showed greater enzymatic activity than ECPs and that the activity of most enzymes ceased after heat treatment (100�C for 10 min). Both strain TA15 and strain TA2 produced hydroxamate siderophores, although the activity was greater in strain TA15. ECPs from both bacterial species at high concentrations, as well as viable bacteria, caused significant reductions in hemocyte survival after 4 h of incubation, whereas no significant differences in viability were observed during incubation with heat-killed bacteria.


1999 ◽  
Vol 65 (2) ◽  
pp. 241-251 ◽  
Author(s):  
Tadahide Kurokawa ◽  
Tohru Suzuki ◽  
Masanori Okauchi ◽  
Satoshi Miwa ◽  
Kiyohito Nagai ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhe Zheng ◽  
Yongshan Liao ◽  
Jianming Ye ◽  
Chuangye Yang ◽  
Linda Adzigbli ◽  
...  

Environmental microbiota plays a vital role in the intestinal microbiota of aquatic organisms. However, data concerning the association between the intestinal microbiota of pearl oyster Pinctada fucata martensii and the surrounding seawater are limited. The existing bacterial communities in pearl oyster intestine and surrounding water from two sites (D and H, within Liusha Bay in Guangdong, China) were investigated using 16S rRNA-based sequencing to explore the relationship among the two. D located in the inner bay, and H located in the open sea area outside bay. Results revealed the richness and diversity of pearl oyster intestinal microbiota to be less than those of the surrounding water, with 38 phyla and 272 genera observed as a result of the classifiable sequence. The microbiota compositions in the intestine and the surrounding water were diversified at the phylum and genus levels, with the sequencing data being statistically significant. However, the functional prediction of microbiota emphasized the overall similarity in the functional profile of the surrounding seawater and intestinal microbiomes. This profile was associated with metabolism of cofactors and vitamin, carbohydrates metabolism, amino acids metabolism, metabolism of terpenoids, and polyketides, metabolism of other amino acids, lipids metabolism, and energy metabolism. Seven common operational taxonomic units (OTUs), which belonged to phyla Tenericutes, Cyanobacteria, and Planctomycetes, were noted in the intestines of pearl oysters from two different sites. These OTUs may be affiliates to the core microbiome of pearl oyster. Significantly different bacterial taxa in the intestines of pearl oysters from two different sites were found at the phylum and genus levels. This finding suggested that the bacterial communities in pearl oyster intestines may exhibit some plasticity to adapt to changes in the surrounding water-cultured environment. This study generally offers constructive discoveries associated with pearl oyster intestinal microbiota and provides guidance for sustainable aquaculture.


1999 ◽  
Vol 37 ◽  
pp. 1-12 ◽  
Author(s):  
T Miyazaki ◽  
K Goto ◽  
T Kobayashi ◽  
T Kageyama ◽  
M Miyata

2021 ◽  
Author(s):  
Fatemeh Parvizi ◽  
Arash Akbarzadeh ◽  
Ahmad Farhadi ◽  
Sophie Arnaud-Haond ◽  
Mohammad Sharif Ranjbar

Abstract A few species of mollusks display color variation in their soft tissues. In pearl oysters, the color polymorphism in mantle tissue is associated with the color and radiance of shell and pearl. The study of biomineralization related genes in mantle tissue of pearl oysters can be used as a suitable approach to better identify the molecular mechanisms that influence shell and pearl quality and color variations. In this study, we investigated the transcription of biomineralization-related genes in black and orange mantle morphotypes of pearl oyster, Pinctada persica in both warm and cool seasons using quantitative real-time PCR. Our results showed that the genes involved in biomineralization of the prismatic and nacre layer, i.e.; ASP, KRMP, MRNP34, SHELL, SHEM1B, LINKINE, PIF, SHEM5, NACREIN, and in pigmentation (TYR2A) were significantly highly expressed in orange phenotype compared to those of black one, suggesting the existence of different genetic processes between two color morphs of mantle tissue and the more active role of genes in orange morphotype. In black mantle phenotype, ASP, KRMP, SHEM5 and PIF and in the orange phenotype, only KRMP and PRISM showed difference in seasonal expression. This study provides an accurate understanding of the mantle trait of P. persica.


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