scholarly journals Host Body Size, Prevalence, and Breeding Season of the Microparasitic Snail Pelseneeria castanea on the Sea Urchin Strongylocentrotus nudus in Coastal Waters of the Sea of Japan off Western Hokkaido, Japan

2006 ◽  
Vol 61 ◽  
pp. 16-20 ◽  
Author(s):  
Tadashi KAWAI ◽  
Kazuya NAGASAWA
Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.


2017 ◽  
Vol 6 (2) ◽  
pp. 91-95
Author(s):  
Nadezhda Konstantinovna Khristoforova ◽  
Anna Dmitrievna Kobzar

The paper contains the study of heavy metals in three species - Sargassum miyabei , Sargassum pallidum , Cystoseira crassipes in the coastal waters of the Posyet Bay. The analysis of the spatial distribution of trace elements revealed the highest contents of zinc, copper and nickel in the Troitsa Bight, due to recreational pressure and a high concentration of nickel and cadmium in Sivuchya Bight that was caused by transboundary atmospheric transport. All of detected concentrations exceed natural background values for the North-Western part of the Sea of Japan. The authors show that there has been a distinct change in the environmental situation in the the Posyet Bay since 1998: the concentration of lead has sharply decreased, the content of zinc, copper and cadmium has decreased, it could be connected with influence reduction in the free economic zone, located on the Chinese side on the Tumannaya River.


Author(s):  
Amber J. Brace ◽  
Marc J. Lajeunesse ◽  
Daniel R. Ardia ◽  
Dana M. Hawley ◽  
James S. Adelman ◽  
...  

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Fei Zhang ◽  
Wenxin Lin ◽  
Rui Zhang ◽  
Qiang Zheng ◽  
Nianzhi Jiao

Salegentibacter mishustinae KCTC strain 12263 was isolated from the sea urchin Strongylocentrotus intermedius inhabiting the Sea of Japan. Here, we report the draft genome sequence of Salegentibacter mishustinae KCTC 12263. It comprises ~3.78 Mb in 38 contigs with a G+C content of 36.5%, and a total of 3,490 proteins-coding genes were obtained. One complete CRISPR-Cas gene cluster was identified in the genome, which shows the strategy against invasive genetic elements of the strain.


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