Complete sequence of Erwinia piriflorinigrans plasmids pEPIR37 and pEPIR5 and role of pEPIR37 in pathogen virulence

Erwinia piriflorinigrans is a newly described pathogen causing necrosis of pear blossoms. Complete sequencing of the 37‐kb plasmid pEPIR37 common to 27 E. piriflorinigrans strains revealed homology to sequences of the ubiquitous plasmids pEA29 of the fire blight pathogen E. amylovora, plasmid pEP36 of E. pyrifoliae, plasmid pEJ30 of Erwinia sp. from Japan, and genomic regions of the related Rosaceae epiphytic Erwinia species E. tasmaniensis and E. billingiae. A second 5·5‐kb cryptic plasmid pEPIR5, found in 12 E. piriflorinigrans strains, was also sequenced revealing mobilization and replication proteins with similarities to many small ColE1‐type plasmids in Erwinia spp. and other enterobacteria. Functional analyses of pEPIR37 introduced into a strain of E. amylovora cured of pEA29 plasmid, which has a reduced virulence, showed a role in increasing symptom development similar to that observed in E. amylovora carrying plasmid pEA29.     

The Contribution of Naturally Occurring Food Items to the Diet of Bidyanus bidyanus When Fed Differing Formulated Diets

Fish raised in ponds and fed formulated feed also have access to naturally occurring food items. The contribution of these food items to growth of Bidyanus bidyanus was investigated by assigning fish to four treatments: in diet 1, caged fish were fed a high protein feed (52% CP); in diet 2, caged fish were fed a medium protein feed (30% CP); in diet 3, caged fish received no feed; and in diet 4, uncaged fish received no feed. Survival between caged treatments was similar (88%–96%), and fish performed best when fed a high-protein feed. Modelling of C and N stable isotope ratios showed formulated pellets provided 12% to 84% of the growth of fish fed diet 1 or 2, while invertebrates provided between 4% and 74%. The majority of growth of fish in diet 3 was from zooplankton (54%–76%) and invertebrates for fish in diet 4 (6%–94%). Implications for low intensity production of B. bidyanus are discussed.     

Spatial and temporal patterns in summer ichthyoplankton assemblages on the eastern Bering Sea shelf 1996–2007

Larval and early juvenile fishes were sampled from the eastern Bering Sea (EBS) shelf from 2001 to 2005, and in 2007. Data from these collections were used to examine spatial and temporal patterns in species assemblage structure and abundance. The years 2001–2005 were unusual because the EBS water temperature was ‘warm’ compared with the long‐term mean temperature. In contrast, 2007 was a ‘cold’ year. The abundance of the five most numerous taxa at 12 stations common to all years sampled (1996–2005, 2007) were significantly different among years. Larval and early juvenile stage Theragra chalcogramma (walleye pollock), a commercially important gadid, were by far the most abundant fish in all years. Bottom depth alone best explained assemblage structure in most years, but in others, bottom depth and water column temperature combined and percent sea‐ice coverage were most important. Abundance of T. chalcogramma larvae increases with water column temperature until 5°C and then becomes level. Higher abundances of Gadus macrocephalus (Pacific cod) larvae occur in years with the greatest percent sea‐ice cover as indicated by GAM analysis. Larvae of Lepidopsetta polyxystra (northern rock sole) increase in abundance with increasing maximum wind speed, but decrease at a later date during the last winter storm. The data are consistent with the hypothesis that oceanographic conditions, specifically water temperature and sea‐ice coverage, affect the spatial and temporal pattern of larval abundances. In general, ichthyoplankton species assemblages can be important early indicators of environmental change in the Bering Sea and potentially other subarctic seas as well.     

Comparative genomics‐informed design of two LAMP assays for detection of the kiwifruit pathogen Pseudomonas syringae pv. actinidiae and discrimination of isolates belonging to the pandemic biovar 3

The aim of this study was to develop a rapid, sensitive and reliable field‐based assay for detection of the quarantine pathogen Pseudomonas syringae pv. actinidiae (Psa), the causal agent of the most destructive and economically important bacterial disease of kiwifruit. A comparative genomic approach was used on the publicly available Psa genomic data to select unique target regions for the development of two loop‐mediated isothermal amplification (LAMP) assays able to detect Psa and to discriminate strains belonging to the highly virulent and globally spreading Psa biovar 3. Both LAMP assays showed specificity in accordance with their target and were able to detect reliably 125 CFU per reaction in less than 30 min. The developed assays were able to detect the presence of Psa in naturally infected kiwifruit material with and without symptoms, thus increasing the potential of the LAMP assays for phytosanitary use.     

Copepod dynamics across warm and cold periods in the eastern Bering Sea: Implications for walleye pollock (Gadus chalcogrammus) and the Oscillating Control Hypothesis

Differences in zooplankton populations in relation to climate have been explored extensively on the southeastern Bering Sea shelf, specifically in relation to recruitment of the commercially important species walleye pollock (Gadus chalcogrammus). We addressed two research questions in this study: (i) Does the relative abundance of individual copepod species life history stages differ across warm and cold periods and (ii) Do estimated secondary production rates for copepods differ across warm and cold periods? For most copepod species, warmer conditions resulted in increased abundances in May, the opposite was observed in colder conditions. Abundances of smaller‐sized copepod species did not differ significantly between the warm and cold periods, whereas abundances of larger‐sized Calanus spp. increased during the cold period during July and September. Estimated secondary production rates in the warm period were highest in May for smaller‐sized copepods; production in the cold period was dominated by the larger‐sized Calanus spp. in July and September. We hypothesize that these observed patterns are a function of temperature‐driven changes in phenology combined with shifts in size‐based trophic relationships with primary producers. Based on this hypothesis, we present a conceptual model that builds upon the Oscillating Control Hypothesis to explain how variability in copepod production links to pollock variability. Specifically, fluctuations in spring sea‐ice drive regime‐dependent copepod production over the southeastern Bering Sea, but greatest impacts to upper trophic levels are driven by cascading July/September differences in copepod production.     

Canine pedal injury resulting from metal landscape edging

Background – This study was performed to document the frequency and severity of limb injuries that occur when dogs come in contact with metal landscape edging. A retrospective study from 1997 to 2007 was performed at Colorado State University veterinary teaching hospital. Sixty dogs were admitted to hospital for traumatic limb injuries resulting from metal landscape edging identified by a computerized medical records search. Key Findings – Most dogs were young, large breed dogs. All 60 dogs suffered traumatic pedal lacerations when contacting metal landscape edging, the majority of which occurred on the forelimbs. Eighty‐five percent required surgical repair. All 60 dogs were discharged from the hospital and 30 were available for long‐term follow‐up. While most dogs healed with a perfect cosmetic outcome, 3 dogs with tendon involvement developed residual digital deformities. Significance – Dogs are at risk of injury when exposed to metal landscape edging. Severity of pedal injury determines treatment protocol and prognosis for recovery.     

The structure of the upper atmosphere of mars: In situ accelerometer measurements from mars global surveyor

The Mars Global Surveyor (MGS) z-axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have been detected on opposite sides of the planet near 90 degreesE and 90 degreesW, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere.     

Xanthomonas arboricola pv. fragariae: what's in a name?

Polyphasic analysis exposed important heterogeneity between bacterial strains catalogued as Xanthomonas arboricola pv. fragariae (Xaf) from different culture collections. Two draft whole‐genome sequences revealed pathogenicity related genes of the type‐three secretion system in strain LMG 19146, whereas none were found in the Xaf pathotype strain LMG 19145. Also, considerable sequence divergence was observed in the phylogenetic marker genes gyrB, rpoD, dnaK and fyuA. Further study of 16 Xaf culture‐collection strains showed that co‐classification is not justified. Partial 16S rRNA gene and gyrB sequencing demonstrated that 12 strains belonged to X. arboricola, but that they did not form one homogeneous group within the species. The four remaining strains were identified as Xanthomonas fragariae and Xanthomonas sp. All sequence‐based identifications were confirmed by MALDI‐TOF MS fingerprinting. Also, the pathogenicity genes hrcQ and avrBs2 were detected in only three of the 12 analysed X. arboricola strains. The X. arboricola and Xanthomonas sp. strains showed pectolytic activity, and upon inoculation in strawberry none of the strains reproduced the leaf blight symptoms reported for Xaf. This study demonstrates that (i) no clear criteria exist for the identification of strains as Xaf, (ii) the name Xaf is currently used for a genetically diverse assortment of strains, and (iii) the species X. arboricola holds many undetermined plant‐associated bacteria besides the described pathovars.     

Differences in production values between high- and low-productivity swine breeding herds

Data were collected from 80 North American users of a computerized health and management software program for the period August 1985 through July 1986. Fifty-four herds were selected for analysis based on selection criteria of 1) stable herd inventory, 2) complete recorded data, 3) weaning-to-first service interval greater than 3 d and less than 20 d, and 4) culling rate greater than 10%. These herds had an average of 18.2 pigs weaned/(female.year) (PWFY), 2.1 litters/(female.year) (LFY), 81% farrowing rate, 10.2 pigs born live/litter and 14.5% preweaning mortality. Compared with the 14 herds with the lowest values for pigs weaned/(female.year), high-productivity herds (i.e., the 14 herds with the highest values for PWFY) had higher LFY, farrowing rate, total and live pigs born/litter and sow-gilt ratio; they also had lower nonproductive female days (NPFD), lower preweaning mortality and fewer gilts as a proportion of female inventory. Herd size and PWFY were not correlated. A negative correlation between herd size and pigs born live remained after controlling for average lactation length (r = -.30). Nonproductive female days was highly correlated with LFY (r = -.87). Increasing herd age, measured by the sow-gilt ratio, was associated mainly with a reduction in NPFD, although there was a slight positive association with pigs born alive (r = .29).