Peel tissue α-farnesene and conjugated trienol concentrations during storage of ‘White Angel’בRome Beauty’ hybrid apple selections susceptible and resistant to superficial scald

In a 2-year study, fruit from eight red- and eight yellow-skinned ‘White Angel’בRome Beauty’ hybrid selections were stored for 21 weeks at 0.5°C plus 1 week at 20°C and evaluated for the incidence and severity of superficial scald. Five red-skinned (R-03, R-20, R-22, R-48 and R-85) and three yellow-skinned (Y-26, Y-55 and Y-65) selections were examined in both seasons. Peel-tissue samples taken at 0, 7, 14 and 21 weeks of storage were analyzed for concentrations of α-farnesene and its conjugated trienol (CTol) oxidation products by HPLC with UV detection. Three red-fruited (R-44, R-48 and R-85) and five yellow-fruited (Y-38, Y-40, Y-55, Y-65 and Y-67) lines exhibited scald symptoms. The remaining lines (R-01, R-03, R-16, R-20, R-22, Y-07, Y-26 and Y-28) were free of scald. Overall, production of α-farnesene and accumulation of CTols were not closely correlated with scald susceptibility. Data for the selections most prone to scald, Y-65, Y-40 and R-44, were consistent with the proposed role of α-farnesene oxidation products in scald induction, but for Y-55 and R-48, which developed mild to moderate scald and accumulated very little CTols, the data conflicted with the α-farnesene oxidation–scald induction hypothesis. Also, scald-resistant lines Y-07 and R-22 produced high levels of α-farnesene and reached CTol concentrations comparable to those in several scald-susceptible lines. We conclude that if CTol do play a role in scald induction, there must be other mitigating factors of at least equal importance. Moreover, our findings support the proposal that oxidation products of α-farnesene are not essential for scald development in fruit with severely compromised antioxidative defenses, but free radicals and/or toxic volatiles generated by α-farnesene oxidation can exacerbate scald symptoms.     

Soil enzyme activities and abundance of microbial functional genes involved in nitrogen transformations in an organic farming system

Organic farming systems receive organic amendments to maintain soil fertility and supply nutrients for plant growth. This study investigated the effect of organic fertilizers (no amendment as control, compost, and manure), and their interaction with cover crops (millet, buckwheat, and black turtle bean) on soil enzyme activities, N transformation rates, and functional gene abundances under an organic production system. Organic N fertilizers had a stronger effect than cover crop type on soil function and functional gene abundances. Soil enzyme activities were increased by both compost and manure, but there were few differences between these treatments. Nitrification potential, nitrite oxidation potential, and denitrification potential were significantly higher in manure-treated than in control and compost-treated soils, indicating application of manure had a higher N loss potential than compost application in this organic farming system. Organic N fertilizers significantly increased the abundance of some genes involved in N mineralization, ammonification, and nitrification (sub, ureC, bacterial amoA and nxrB). The activity of ammonia-oxidizing bacteria and archaea were both increased by organic N fertilizers, and their activities were higher in manure-treated than in compost-treated soils. Overall, the abundance of functional genes was significantly correlated with their corresponding enzyme activity. However, functional gene abundance was less important than soil chemical and microbiological properties in explaining the variation in the corresponding enzyme activity.     

Comparing the minimum inhibitory and mutant prevention concentrations of selected antibiotics against animal isolates of Pasteurella multocida and Salmonella typhimurium

Historically, the use of antibiotics was not well regulated in veterinary medicine. The emergence of antibiotic resistance (ABR) in pathogenic bacteria in human and veterinary medicine has driven the need for greater antibiotic stewardship. The preservation of certain antibiotic classes for use exclusively in humans, especially in cases of multidrug resistance, has highlighted the need for veterinarians to reduce its use and redefine dosage regimens of antibiotics to ensure efficacy and guard against the development of ABR pathogens. The minimum inhibitory concentration (MIC), the lowest concentration of an antibiotic drug that will prevent the growth of a bacterium, is recognised as a method to assist in antibiotic dosage determination. Minimum inhibitory concentrations sometimes fail to deal with first-step mutants in bacterial populations; therefore dosing regimens based solely on MIC can lead to the development of ABR. The mutant prevention concentration (MPC) is the minimum inhibitory antibiotic concentration of the most resistant first-step mutant. Mutant prevention concentration determination as a complementary and sometimes preferable alternative to MIC determination for veterinarians when managing bacterial pathogens. The results of this study focused on livestock pathogens and antibiotics used to treat them, which had a MIC value of 0.25 µg/mL for enrofloxacin against all 27 isolates of Salmonella typhimurium. The MPC values were 0.50 µg/mL, with the exception of five isolates that had MPC values of 4.00 µg/mL. The MPC test yielded 65.52% (18 isolates) Salmonella isolates with florfenicol MICs in the sensitive range, while 11 isolates were in the resistant range. Seventeen isolates (58.62%) of Pasteurella multocida had MIC values in the susceptible range and 41.38% (12 isolates) had an intermediate MIC value. Mutant prevention concentration determinations as done in this study is effective for the antibiotic treatment of bacterial infections and minimising the development of resistance. The MPC method can be used to better control to prevent the development of antibiotic drug resistance used in animals.     

Growth,Consumption and Respiration by Larvae of the Kelp-Fly Fucellia Capensis (Diptera:Anthomyiidae)

At 18 °C the eggs of the kelp-fly, Fucellia capensis, hatch in 24 – 32 h and the larval and pupal stages last 10 – 12 and 9 – 14 days respectively. The growth curve is discontinuous, with declining relative growth rates in successive larval instars. Food consumption is relatively independent of size, at 0,25 mg dry kelp mg^-1 wet larva day^-1. Respiration rate is related to larval mass by the equation: Respiration rate (μl O₂ h^-1) = 2,75 (wet mass larva)^0,66. In terms of energy an individual larva consumes 245,5 J over its lifespan, grows to the equivalent of 43,9 J and respires 51,6 J, indicating an assimilation efficiency of 30% and a gross growth efficiency of 17%. Kelp-fly larvae are probably less significant consumers of drift kelp than amphipods or isopods, but they promote the decay of wrack beds and are favoured as food by sea-shore birds.     

Amphibian therapeutics.

The treatment of diseases in amphibians presents unique challenges for the clinician. This article describes the basic principles in selecting and administering therapeutics, and provides drug dose rates used successfully in amphibians. The importance of proper husbandary and hygiene, as it relates to amphibian health and medical management of disease, is also emphasized.     

Paramyxovirus infection in caiman lizards (Draecena guianensis).

Three separate epidemics occurred in caiman lizards (Dracaena guianensis) that were imported into the USA from Peru in late 1998 and early 1999. Histologic evaluation of tissues from necropsied lizards demonstrated a proliferative pneumonia. Electron microscopic examination of lung tissue revealed a virus that was consistent with members of the family Paramyxoviridae. Using a rabbit polyclonal antibody against an isolate of ophidian (snake) paramyxovirus, an immunoperoxidase staining technique demonstrated immunoreactivity within pulmonary epithelial cells of 1 lizard. Homogenates of lung, brain, liver, or kidney from affected lizards were placed in flasks containing monolayers of either terrapene heart cells or viper heart cells. Five to 10 days later, syncytial cells formed. When Vero cells were inoculated with supernatant of infected terrapene heart cells, similar syncytial cells developed. Electron microscopic evaluation of infected terrapene heart cells revealed intracytoplasmic inclusions consisting of nucleocapsid strands. Using negative-staining electron microscopy, abundant filamentous nucleocapsid material with a herringbone structure typical of the Paramyxoviridae was observed in culture medium of infected viper heart cells. Seven months following the initial epizootic, blood samples were collected from surviving group 1 lizards, and a hemagglutination inhibition assay was performed to determine presence of specific antibody against the caiman lizard isolate. Of the 17 lizards sampled, 7 had titers of < or =1:20 and 10 had titers of >1:20 and < or =1:80. This report is only the second of a paramyxovirus identified in a lizard and is the first to snow the relationship between histologic and ultrastructural findings and virus isolation.     

Comparison of Protein Phosphatase Inhibition Assay with LC-MS/MS for Diagnosis of Microcystin Toxicosis in Veterinary Cases

Microcystins are acute hepatotoxins of increasing global concern in drinking and recreational waters and are a major health risk to humans and animals. Produced by cyanobacteria, microcystins inhibit serine/threonine protein phosphatase 1 (PP1). A cost-effective PP1 assay using p-nitrophenyl phosphate was developed to quickly assess water and rumen content samples. Significant inhibition was determined via a linear model, which compared increasing volumes of sample to the log-transformed ratio of the exposed rate over the control rate of PP1 activity. To test the usefulness of this model in diagnostic case investigations, samples from two veterinary cases were tested. In August 2013 fifteen cattle died around two ponds in Kentucky. While one pond and three tested rumen contents had significant PP1 inhibition and detectable levels of microcystin-LR, the other pond did not. In August 2013, a dog became fatally ill after swimming in Clear Lake, California. Lake water samples collected one and four weeks after the dog presented with clinical signs inhibited PP1 activity. Subsequent analysis using liquid chromatography-mass spectrometry (LC-MS/MS) detected microcystin congeners -LR, -LA, -RR and -LF but not -YR. These diagnostic investigations illustrate the advantages of using functional assays in combination with LC-MS/MS.     

Outbreak of wildebeest-associated malignant catarrhal fever in Ankole cattle

During an outbreak of malignant catarrhal fever in a herd of Ankole cattle in a zoological collection, two adult cows and one adult bull from a herd of 15 died or were euthanased between July and November 2004. The clinical, gross postmortem and histological findings were typical of the disease in uk native domestic cattle. The diagnosis was confirmed by serology in two animals, and by pcr in all three; the pcr provided evidence of alcelaphine herpesvirus type 1 infection in all three animals and also of ovine herpesvirus type 2 infection in one.     

Multiple predator effects and native prey responses to two non‐native Everglades cichlids

Abstract – Non‐native predators may have negative impacts on native communities, and these effects may be dependent on interactions among multiple non‐native predators. Sequential invasions by predators can enhance risk for native prey. Prey have a limited ability to respond to multiple threats since appropriate responses may conflict, and interactions with recent invaders may be novel. We examined predator–prey interactions among two non‐native predators, a recent invader, the African jewelfish, and the longer‐established Mayan cichlid, and a native Florida Everglades prey assemblage. Using field enclosures and laboratory aquaria, we compared predatory effects and antipredator responses across five prey taxa. Total predation rates were higher for Mayan cichlids, which also targeted more prey types. The cichlid invaders had similar microhabitat use, but varied in foraging styles, with African jewelfish being more active. The three prey species that experienced predation were those that overlapped in habitat use with predators. Flagfish were consumed by both predators, while riverine grass shrimp and bluefin killifish were eaten only by Mayan cichlids. In mixed predator treatments, we saw no evidence of emergent effects, since interactions between the two cichlid predators were low. Prey responded to predator threats by altering activity but not vertical distribution. Results suggest that prey vulnerability is affected by activity and habitat domain overlap with predators and may be lower to newly invading predators, perhaps due to novelty in the interaction.