Etiologic agents, incidence, and improved diagnostic methods of cantharidin toxicosis in horses

In addition to the 3-striped blister beetles (Epicauta temexa and E occidentalis), other sources of equine cantharidin toxicosis were identified at the Texas Veterinary Medical Diagnostic Laboratory and included E albida and E attrivittata and the previously incriminated E pardalis and E pennsylvanica. Improved methods for diagnosing cantharidin or blister beetle toxicosis involve partial purification of urine and gastric content extracts, using silica cartridges, followed by analysis, using capillary gas chromatography/mass spectrometry. During a 26-month period, 53 episodes of cantharidin toxicosis in horses were confirmed at our diagnostic laboratory. Concentrations of cantharidin in urine and gastric contents ranged from 0.0003 to 3.50 micrograms/g. Peak incidences were observed in late summer and early fall.     

COMPARISON OF THREE RADIOGRAPHIC CONTRAST PROCEDURES IN THE EVALUATION OF THE CANINE LUMBOSACRAL SPINAL CANAL

Lumbar myelography, intraosseous caudal vertebral venography, and epidurography were performed in 12 normal, mature mixed-breed dogs. The radiographic appearance of the lumbosacral region was evaluated in both the lateral and ventrodorsal projections. These three radiographic contrast procedures were repeated in the same dogs after the introduction of a silicone mass into the spinal canal at the lumbosacral junction. The radiographic findings were compared with postmortem findings to determine which contrast procedure was most useful in detecting the mass in the lumbosacral spine. None of the procedures evaluated consistently produced good-quality studies in the normal dogs. After introduction of the silicone mass, lumbosacral epidurography yielded the largest number of positive correlations. However, the sensitivity of lumbosacral epidurography was less than 50% in the lateral projection and less than 20% in the ventrodorsal projection. Though none of the procedures were consistently helpful in the diagnosis of the lumbosacral masses, lumbosacral epidurography has the most potential to give consistently good-quality studies and thereby a greater probability of detecting an abnormality.     

Chemistry and Bioactivity of the Deep-Water Antarctic Octocoral Alcyonium sp.

Chemical investigation of an Antarctic deep-water octocoral has led to the isolation of four new compounds, including three illudalane sesquiterpenoids (1–3) related to the alcyopterosins, a highly oxidized steroid, alcyosterone (5), and five known alcyopterosins (4, 6–9). The structures were established by extensive 1D and 2D NMR analyses, while 9 was verified by XRD. Alcyopterosins are unusual for their nitrate ester functionalization and have been characterized with cytotoxicity related to their DNA binding properties. Alcyopterosins V (3) and E (4) demonstrated single-digit micromolar activity against Clostridium difficile, an intestinal bacterium capable of causing severe diarrhea that is increasingly associated with drug resistance. Alcyosterone (5) and several alcyopterosins were similarly potent against the protist Leishmania donovani, the causative agent of leishmaniasis, a disfiguring disease that can be fatal if not treated. While the alcyopterosin family of sesquiterpenes is known for mild cytotoxicity, the observed activity against C. difficile and L. donovani is selective for the infectious agents.     

Differential responses of amphibians and reptiles in riparian and stream habitats to land use disturbances in western Georgia, USA

Urban and agricultural land uses have caused documented declines in diversity of many organisms. However, responses of stream- and riparian-dwelling amphibians and reptiles to anthropogenic land development are collectively understudied and, when studied, are often grouped together as though these two taxa respond in a similar fashion. We surveyed watersheds in four land use categories (reference, pasture, developing, and urban) for amphibian and reptile species richness over a two-year period in the southeastern United States. Total herpetofauna species richness was equivalent among all watershed types, but amphibians and reptiles responded differently to urbanization when analyzed separately. Urban watersheds had significantly fewer amphibian species than all other watershed types, but these losses were counterbalanced by significant increases in reptile species richness in these same watersheds. We also found that local, riparian-scale, habitat differences were strongly correlated with species composition differences between pasture and developing watersheds. While the difference in species composition between pasture and developing sites may have multiple, species-specific explanations, the dramatic differences between amphibian and reptile species richness in urban watersheds suggest broad trends that may be important to conservation planning. Specifically, our observations suggest that urbanization in the studied watersheds alters small streams from closed-canopy, shallow-water features of the forested landscape likely present before settlement by Europeans and favored by many salamanders and frogs to features associated with open vegetation and deeper, warmer waters favored by riverine turtles and snakes. We conclude that amphibians and reptiles, despite some physiological similarities, are not equivalent for monitoring purposes. Additionally, if future development in the Piedmont mirrors current urbanization, then significant faunal shifts seem assured.     

Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations

Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern USA by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. Fine particulates such as those resulting from smelting operations may disperse more readily into the environment than coarser tailings dust. Fine particles also penetrate more deeply into the human respiratory system and may become more bioavailable due to their high specific surface area. In this work, we report the size-fractionated chemical characterization of atmospheric aerosols sampled over a period of a year near an active mining and smelting site in Arizona. Aerosols were characterized with a ten-stage (0.054 to 18???m aerodynamic diameter) multiple orifice uniform deposit impactor (MOUDI), a scanning mobility particle sizer (SMPS), and a total suspended particulate collector. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0???m diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as Aeolian dust from mine tailings and other sources. Observation of ultrafine particle number concentration (SMPS) show the highest readings when the wind comes from the general direction of the smelting operations site.     

Water content in convective storm clouds

The condensed water content of convective storms was measured by the use of a penetrating aircraft. Regions 1 to 2 kilometers in extent and having condensed water contents of about 20 grams per cubic meter were found to be definite features of the cloud interior.     

Cultivation of the Paracalanid Copepod,Bestiolina similis (Calanoida: Crustacea)

First feed production continues to be a major barrier to the cultivation of many fish species. Although copepod nauplii are a suitable food, consistency and high production have been difficult. Temporal changes in production in batch cultures of the calanoid copepod, Bestiolina similis, were investigated to develop management strategies for the use of copepod nauplii as a live food. Population abundances and female egg production rates were measured, and recruitment and mortality rates were calculated. Relative expression levels of a molecular biomarker for stress, heat shock protein hsp70, were determined using real‐time quantitative polymerase chain reaction. The population cycle included a period of rapid increase in abundances, followed by a steep decline and a period of stable but low population densities. Initially, egg production exceeded 25 eggs per female per day and low mortality rates prevailed. The population decline was preceded by upregulation of hsp70 and followed by an 80–90% decline in female fecundity and an increase in mortality rates. Egg production rates remained below four eggs per female per day even after new generations of females reached adulthood. The predictable population cycle provides opportunities to coordinate nauplius production rates with first feed needs of fish larvae.     

Production Comparison of Three Genetic Strains of Freshwater Prawn,Macrobrachium rosenbergii,Raised Under Two Pond Management Technologies

Three genetic strains (Texas [cultured], Hawaii [cultured], and Myanmar [wild]) of freshwater prawn, Macrobrachium rosenbergii, were characterized and compared under two pond grow‐out management technologies using a 3 × 2 factorial design. Juvenile prawns (45 d nursed juveniles) from each strain were stocked at individual average weights of 0.4 ± 0.3 g (Texas), 0.3 ± 0.2 g (Hawaii), and 0.3 ± 0.2 g (Myanmar). The low input management technology prawns were stocked at 24,700 /ha with no added substrate. The high input management technology prawns were stocked at 74,100 /ha with the addition of artificial substrate. Each of the six treatment combinations were replicated in three, 0.04 ha earthen ponds (total of 18 ponds). Prawns were fed a sinking pellet (32% protein) once daily at a standardized rate. After 112 d, prawns were harvested, bulk weighed, and counted. Survival of Texas strain (95%) was significantly higher (P ≤ 0.05) than Myanmar strain (77–80%) under both management technologies with survival of Hawaii strain (86–91%) intermediate and not significantly different (P > 0.05) from other strains. Under both management technologies, average weight, total production, and marketable percentage (>20 g) was significantly better (P ≤ 0.05) in Texas and Hawaii strains in comparison to the Myanmar strain. These data appear to indicate that the cultured strains evaluated in this study demonstrate positive impacts of domestication and do not indicate inbreeding depression.     

Linking long-term dietary patterns with gut microbial enterotypes

Diet strongly affects human health, partly by modulating gut microbiome composition. We used diet inventories and 16S rDNA sequencing to characterize fecal samples from 98 individuals. Fecal communities clustered into enterotypes distinguished primarily by levels of Bacteroides and Prevotella. Enterotypes were strongly associated with long-term diets, particularly protein and animal fat (Bacteroides) versus carbohydrates (Prevotella). A controlled-feeding study of 10 subjects showed that microbiome composition changed detectably within 24 hours of initiating a high-fat/low-fiber or low-fat/high-fiber diet, but that enterotype identity remained stable during the 10-day study. Thus, alternative enterotype states are associated with long-term diet.