In vivo growth and genomic characterization of rickettsia-like organisms isolated from farmed Chinook salmon (Oncorhynchus tshawytscha) in New Zealand

2018 ◽  
Vol 41 (8) ◽  
pp. 1235-1245 ◽  
Author(s):  
E Gias ◽  
C L Brosnahan ◽  
D Orr ◽  
B Binney ◽  
H J Ha ◽  
...  
1998 ◽  
Vol 66 (2) ◽  
pp. 567-572 ◽  
Author(s):  
William R. Schwan ◽  
Silvija N. Coulter ◽  
Eva Y. W. Ng ◽  
Michael H. Langhorne ◽  
Heather D. Ritchie ◽  
...  

ABSTRACT Staphylococcus aureus is an important pathogen of humans and other animals, causing bacteremia, abscesses, endocarditis, and other infectious syndromes. A signature-tagged mutagenesis (STM) system was adapted for use in studying the genes required for in vivo survival of S. aureus. An STM library was ultimately created in S. aureus RN6390, with Tn917 being used to create the transposon mutations. Pools of S. aureusRN6390 mutants were screened in mouse abscess, bacteremia, and wound infection models for growth attenuation after in vivo passage. One of the mutants that was identified displayed marked attenuation following large-pool screening in all three animal models, which was confirmed in bacteremia and endocarditis models of infection with a smaller pool of mutants. Sequence analysis of the entire open reading frame showed a 99% identity to the high-affinity proline permease (putP) gene characterized in another strain of S. aureus. In wound and murine abscess infection models, the putP mutant was approximately 10-fold more attenuated than was wild-type strain RN6390. Another S. aureus strain transduced with theputP mutation also displayed an attenuated phenotype after passage in the wound model. A [3H]proline uptake assay showed that less proline was specifically transported into theputP mutant than into strain RN6390. The reduced viability of the bacteria possessing the mutation in the S. aureushigh-affinity proline permease suggests that proline scavenging by the bacteria is important for in vivo growth and proliferation and that analogs of proline may serve as potential antistaphylococcal therapeutic agents.


NIR news ◽  
2018 ◽  
Vol 29 (5) ◽  
pp. 12-14
Author(s):  
Matthew R Miller ◽  
Jonathan Puddick ◽  
Jane E Symonds ◽  
Seumas P Walker ◽  
Hong (Sabrina) Tian

Near infrared spectroscopy has been employed to determine the proximate composition of Chinook salmon ( Oncorhynchus tshawytscha) and Greenshell Mussels™ ( Perna canaliculus). This work was presented at the Australian Near Infrared Spectroscopy Group and New Zealand Near Infrared Spectroscopy Society meeting in Rotorua, 11–12 April 2018, where it won the best overall presentation award for Near Infrared Science (Figure 1).


1997 ◽  
Vol 54 (6) ◽  
pp. 1246-1254 ◽  
Author(s):  
M J Unwin

Fry-to-adult survival rates for chinook salmon (Oncorhynchus tshawytscha) from Glenariffe Stream, a tributary of the Rakaia River, New Zealand, were estimated for fish of both natural and hatchery origin. Survival of naturally produced fry, most of which leave Glenariffe Stream within 24 h of emergence, averaged 0.079% (range 0.013-1.17%). For hatchery fish released at 8-12 months, standardised to a mean weight of 38 g, survival covaried with weight at release consistently across all brood years and averaged 0.34% (range 0.008-3.28%). Survival rates for hatchery fish were four times higher than for naturally produced fry, but were extremely poor relative to their size at release. Survival rates for fish of natural and hatchery origin were positively correlated, suggesting that recruitment of both stocks is primarily controlled by common influences within the marine environment, probably during the first winter at sea. Stock-recruitment analysis for the natural population showed little tendency for recruitment to increase with stock size, suggesting that marine survival rates may be density dependent. Although the reasons for the relatively poor survival of hatchery fish are unclear, the results provide a case study in which hatchery fish appear to have a poorer ``fitness to survive'' than their natural counterparts.


1998 ◽  
Vol 55 (8) ◽  
pp. 1946-1953 ◽  
Author(s):  
Michael T Kinnison ◽  
Martin J Unwin ◽  
William K Hershberger ◽  
Thomas P Quinn

Interpopulation differences in several adult phenotypic traits suggest that New Zealand (NZ) chinook salmon (Oncorhynchus tshawytscha) are evolving into distinct populations. To further investigate this hypothesis, we compared egg sizes, fecundities, and early development rates of chinook from two NZ streams. The two NZ study populations differed in size-adjusted egg weight and gonadosomatic index, but not in size-adjusted fecundity. Egg weight, fecundity, and gonadosomatic index values for both NZ populations were different than values for chinook from Battle Creek, California, the population regarded as the ancestral NZ stock. In contrast, there was little evidence of divergence in juvenile development. Time to hatching did not differ between the two NZ study populations and heritability estimates were small with large standard errors. Evidence of a small difference in alevin growth rate may have represented an effect of yolk conversion mechanics related to egg size. Despite the similarity in development rates under shared conditions, modeling based on temperature records suggests that emergence dates in the two NZ streams may differ by 4-6 weeks, yielding significant phenotypic differences.


2019 ◽  
Author(s):  
Peter S. Davie ◽  
Seamus P. Walker ◽  
Matthew R. Perrott ◽  
Jane E. Symonds ◽  
Mark Preece ◽  
...  

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