Clonal relatedness of Salmonella isolates associated with invasive infections in captive and wild-caught rattlesnakes

This study examines the serotype distribution and clonal relatedness among Salmonella isolates obtained from healthy and diseased snakes. Isolates from extraintestinal body sites were obtained through routine diagnostic lab submissions from snakes in two facilities that had experienced a high prevalence of osteomyelitis in Crotalus species. Gastrointestinal isolates were predominantly from fecal samples collected from healthy snakes of both crotalid and non-crotalid species in one facility. PFGE macrorestriction analysis of Salmonella isolates confirmed the clonal and species-restricted nature of Salmonella serotype IIIa 56: z4, z23: - in one facility. Fourteen of 15 isolates from suspected osteomyelitis lesions in wild-caught snakes at the second facility were also from Salmonella subgroup IIIa (serotype IIIa 18: z4, z23: -) and appeared to be closely related by PFGE. Evaluation of a PCR assay for the spvC gene in 209 isolates demonstrated that this method consistently distinguished isolates of subgroup IIIa from those of subgroup IIIb. The data presented establish that Salmonella of subgroup IIIb are abundant and regularly associated with gastrointestinal shedding in snakes but that Salmonella in subgroup IIIa disproportionately cause infections in bone or other extraintestinal sites.     

虎斑颈槽蛇的生殖生态学探讨

虎斑颈槽蛇雄性睾丸于５ 月达最大值,随后逐渐减小,到冬眠期至最轻。雌性产卵期为６ ～７ 月中旬,卵生,一年一次性产卵６ ～２２ 枚,孵化期为４１ ～４３ ｄ。本文较详细观察和描述了１１ ～１６ 期胎蛇的外部形态特征和发育时序。     

Hepatic CT attenuation differs in three species of freshwater turtles and hepatic Hounsfield units increase with folliculogenesis in wild Blanding's turtles (Emydoidea blandingii)

Freshwater turtle species are suffering from anthropocentric‐caused population declines, making preservation of professionally managed populations increasingly important. Turtles under professional care have an increased risk to develop hepatic lipidosis, potentially resulting in early death. Computed tomography can provide an antemortem screening for increased fatty liver composition. A goal of this prospective analytical cross‐sectional study was to assess the hepatic attenuation measured as Hounsfield units (HU) in a wild population of a freshwater turtle species, and then compare hepatic HU to freshwater turtles under professional care. Ninety‐five wild Blanding's turtles (BT; Emydoidea blandingii) as well as 10 Vietnamese Pond turtles (VPT; Mauremys annamensis) and six Northern Snake‐Necked turtles (NSNT; Chelodina oblonga) under professional care underwent CT with quantification of hepatic HU. Hepatic HU were correlated to serum chemistry findings and the presence of follicles was recorded in BT. The mean (±SD) hepatic attenuation for 95 wild BT was 97.5 HU ±9.6. There were significant differences in hepatic attenuation among VPT, NSNT, and BT, with median HU values (range) of 5.39 HU (–6.45 to 61.50), 71.74 HU (59.44‐94.49), and 95.43 HU (74.41‐124.56), respectively. Aspartate aminotransferase (AST) values had a weak negative correlation to HU with a coefficient of –0.85 (P < .001). The hepatic attenuation was significantly higher for individuals undergoing folliculogenesis (P = .007). The decreased HU values were significantly negatively correlated with AST values. Findings supported the use of CT as an aid for guiding future management practices in freshwater turtles.     

Inhibitory effect of cytotoxin 1 from Naja atra Cantor venom on K562 cells

AIM: To investigate the inhibitory effect of cytotoxin 1 (CTX1) from Naja atra Cantor venom on human chronic myeloid leukemia cell line K562.METHODS: The MTS and cell counting methods were used to detect cell relative viability and cell numbers of K562 cells treated with CTX1 at different concentrations. In the living culture system, the dead and dying cells stained by PI were observed by inverted fluorescence microscope. After treated with CTX1, the apoptotic cells were detected by flow cytometry with annexinV-FITC and PI double staining.RESULTS: The relative viabilities of K562 cells were (90.50±3.07)%, (58.33±3.08)% and (27.43±1.99)% when the cells were treated with CTX1 for 24 h at the concentrations of 2, 5 and 10 mg/L,respectively. The median inhibitory concentration of CTX1 on K562 cells was 5.77 mg/L after 24-hour treatment. Comparment with control group, the percentages of K562 cells by cell counting were (85.01±3.54)%, (56.65±3.59)% and (43.24±4.15)% after treatment with 8 mg/L of CTX1 for 6 h, 12 h, 24 h,respectively. As treatment concentration of CTX1 was elevated and treatment time was prolonged, the cells stained by PI were remarkably observed under inverted fluorescence microscope. After treatment with CTX1 at 8 mg/L for 6 h, 12 h and 24 h, the incidences of cell necrosis were (0.73±0.06)%, (13.90±0.46)% and (23.33±0.86)%, respectively, and the incidences of late apoptosis were (16.27±0.21)%, (26.90±1.23)% and (18.77±0.81)%, respectively.CONCLUSION: CTX1 possesses obvious inhibitory effect on K562 cells and it mainly causes the late phase of apoptosis and necrosis.     

浅谈Snake模型在图像特征轮廓提取中的应用

本文主要介绍Snake模型在X光手腕骨图像特征轮廓提取中的应用。并且在以往的Snake理论基础之上，结合具体的问题，对Snake模型进行了改进。获得具有较高质量的边缘，同时也保证了特征曲线的闭合性。     

Snake species distributions and temperate grasslands: A case study from the American tallgrass prairie

Many snake species are declining globally, yet data unavailability in temperate grasslands hinders snake conservation in one of the world’s most endangered biomes. To encourage and inform the conservation of snakes in these regions, I examined snake species diversity and abundance during 2 years of a mark-recapture study at 22 sites located in six American tallgrass prairie preserves in northern Illinois, USA. I emphasized landscape-scale relationships after accounting for covariance with environmental factors at both finer (microhabitat) and broader (regional) scales. A total of 120 snakes representing seven species was captured using drift fence arrays associated with funnel traps and sheet metal cover. The low numbers and diversity of snakes captured, when compared to historic evidence, indicate that since the 1930s Midwestern snake populations have declined. Non-metric multidimensional scaling and Mantel tests demonstrate that differences in snake species composition in remnant and degraded prairies are discernable along gradients of urban and agricultural land cover. However, different patterns of abundance for individual snake species indicate that the relative importance of specific landscape factors differ among species, which has significant conservation implications. Here, I recommend that conservationists use a species-specific approach to manage snake populations. I also stress the need for thorough inventory of snake populations and studies of snake-habitat relationships to advance our understanding of snake ecology and conservation within the little studied temperate grassland habitats of South America and eastern Eurasia.     

Forecasting climate-induced changes in the survival of Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha)

Effective conservation and management of natural resources requires accurate predictions of ecosystem responses to future climate change, but environmental science has largely failed to produce these reliable forecasts. The future response of Pacific salmon (Oncorhynchus spp.) to a changing environment and continued anthropogenic disturbance is of particular interest to the public because of their high economic, social, and cultural value. While numerous retrospective analyses show a strong correlation between past changes in the ocean environment and salmon production within the north Pacific, these correlations rarely make good predictions. Using a Bayesian time-series model to make successive 1-yr-ahead forecasts, we predicted changes in the ocean survival of Snake River spring/summer chinook salmon (O. tshawytscha) from indices of coastal ocean upwelling with a high degree of certainty (R² = 0.71). Furthermore, another form of the dynamic times-series model that used all of the available data indicated an even stronger coupling between smolt-to-adult survival and ocean upwelling in the spring and fall (R² = 0.96). This suggests that management policies directed at conserving this threatened stock of salmon need to explicitly address the important role of the ocean in driving future salmon survival.