Metastatic mineralisation in brushtail possums (Trichosurus vulpecula) from Kawau Island

AIMS: To describe the nature and incidence of metastatic mineralisation in brushtail possums (Trichosurus vulpecula) caught on Kawau Island. METHODS: Wild-caught possums were individually housed in captivity over a 24-month period and fed a cereal-based mash diet. Possums that became debilitated were examined post mortem for evidence of metastatic mineralisation of the heart, major blood vessels and kidneys. Serum and aortic segments were collected from affected animals and were analysed for mineral composition. Non-debilitated animals and possums that were experimentally poisoned with cholecalciferol were examined as a comparison. RESULTS: Fifteen of 42 possums (36%) captured on Kawau Island and housed in captivity were debilitated as a result of metastatic mineralisation of the walls of the aorta and/or of the kidney tubules, with four further possums having evidence of mineralisation when humanely killed. Phosphate and ammonium deposits were found in the aorta, and calcium deposits in the kidney tubules. Serum phosphorus and calcium levels were elevated in the debilitated animals. Similar lesions were found in only one of 288 possums captured from other North Island areas and housed in captivity over the same time period. CONCLUSION: Possums from Kawau Island appear to be more predisposed to metastatic mineralisation than possums from other areas of the North Island. The lesions observed in these possums were similar to those caused by cholecalciferol poisoning.     

Age- and size-related trends in woody plant shoot development: regulatory pathways and evidence for genetic control

Woody plants exhibit significant and predictable patterns of change in morphology and physiology as they become older and larger. Four models of potential pathways controlling these changes are presented: a stimulus-response model in which fully developed organs respond to changes in environment (defined here as everything external to the organ); an extrinsic model in which the attributes of developing organs are determined by environmental factors; an intrinsic model in which changes are a result of programmed changes in gene expression; and an extrinsic-intrinsic model in which changes in gene expression are induced by environmental factors. We review evidence that a genetic component is involved in controlling age- and size-related changes in foliar morphology and physiology and discuss the possibility of complex interactions among model pathways.     

Insect herbivores and pathogens of Alnus species in Uganda

Published documentation of insect pests and pathogens associated with Alnus species in Africa is very scarce. We surveyed damaging insects and pathogens, and arthropod natural enemies on Alnus acuminata and A. nepalensis in Kabale and Mbale districts, Uganda between March 1999 and August 2000 in order to identify the range and relative abundance of arthropods and pathogens associated with the Alnus species. Frequently encountered damaging insects on the Alnus species included Apis mellifera, Apion globulipenne, a Systates sp. (Coleoptera: Curculionidae), Phymateus viridipes, a Lobotrachelus sp. (Coleoptera: Curculionidae), Coloborrtics corticina and some Chrysomelidae. Some species such as Aphis fabae, Parastictococcus multispinosus and a Cacopsylla sp. (Homoptera: Psyllidae) were observed feeding on other agroforestry tree species and/or crops although they generally occurred at low population intensities. Spiders and parasitic Hymenoptera were the most common natural enemies. Diseases were more severe in nurseries than in the field. Damping-off caused by Fusarium oxysporum, Septoria brown leaf spot and stem canker were the most serious diseases of Alnus. The array of damaging insects and pathogens indicates a potential danger to the cultivation of Alnus species in Uganda as adoption of the species for agroforestry continues to expand in the country. In view of the increasing demand for Alnus species for agroforestry in Uganda, regular pest monitoring and appropriate control strategies are necessary.This revised version was published online in November 2005 with corrections to the Cover Date.     

Impact of an experimental PRRSV and Streptococcus suis coinfection on the pharmacokinetics of ceftiofur hydrochloride after intramuscular injection in pigs

This study determined the impact of porcine reproductive and respiratory syndrome virus (PRRSV) and Streptococcus suis coinfection on the pharmacokinetic (PK) profile of ceftiofur hydrochloride in pigs after intramuscular (i.m.) injection. Eighteen clinically normal crossbred gilts were assigned by weight into a challenge group (10 pigs) and control group (eight pigs). Pigs in both groups received a single i.m. injection of ceftiofur hydrochloride (Excenel RTU Sterile Suspension; Zoetis) at a 5 mg/kg BW dose. Serial blood samples were collected to characterize the plasma concentration curve. After a 10 days drug washout period, the challenge group was inoculated with 2 mL of PRRSV isolate VR‐2385 (10^5.75 50% tissue culture infective doses per mL) intranasally and 8 days later inoculated S. suis. When clinical disease was evident, the second PK assessment began in both challenge and control groups. Coinfected pigs demonstrated lower values of AUC and C_MAX, but higher values of Cl/F and Vz/F indicating drug kinetics were altered by infection. The data from this study have implications on ceftiofur treatment regimens in diseased pigs.     

Prevalence,Serovars and Antimicrobial Susceptibility of Salmonella spp. from Wild and Domestic Green Iguanas (Iguana iguana) in Grenada,West Indies

Cloacal swabs from 62 green iguanas (Iguana iguana), including 47 wild and 15 domestic ones from five parishes of Grenada, were sampled during a 4‐month period of January to April 2013 and examined by enrichment and selective culture for the presence of Salmonella spp. Fifty‐five per cent of the animals were positive, and eight serovars of Salmonella were isolated. The most common serovar was Rubislaw (58.8%), a serovar found recently in many cane toads in Grenada, followed by Oranienburg (14.7%), a serovar that has been causing serious human disease outbreaks in Japan. Serovar IV:48:g,z₅₁:‐ (formerly, S. Marina) highly invasive and known for serious infections in children in the United States, constituted 11.8% of the isolates, all of them being from domestic green iguanas. Salmonella Newport, a serovar recently found in a blue land crab in Grenada, comprised 11.8% of the isolates from the green iguanas. The remaining four less frequent serovars included S. Javiana and S. Glostrup. Antimicrobial susceptibility tests conducted by a disc diffusion method against amoxicillin–clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim–sulfamethoxazole showed that drug resistance is minimal, with intermediate susceptibility, mainly to streptomycin, tetracycline and cefotaxime. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars from wild and domestic green iguanas in Grenada, West Indies.     

Australian sperm whales from different whaling stocks belong to the same population

1. Understanding the factors driving population structure in marine mammals is needed to evaluate the impacts of previous exploitation, current anthropogenic threats, conservation status, and success of population recovery efforts.
2. Sperm whales are characterized by a worldwide distribution, low genetic diversity, complex patterns of social and genetic structure that differ significantly within and between ocean basins, and a long history of being commercially whaled. In Australia, sperm whales from the (International Whaling Commission assigned) southern hemisphere ‘Division 5’ stock were very heavily exploited by whaling.
3. The present study assessed the potential effects of whaling on the genetic diversity of sperm whales in Australia and the population genetic structure of these whales within a global context. A combination of historical and contemporary sperm whale samples (n = 157) were analysed across six regions, from south-eastern Australia (‘Division 6’ stock in the Pacific Ocean) to south-western Australia (‘Division 5’ stock in the Indian Ocean).
4. Sperm whales sampled from the ‘Division 5’ and ‘Division 6’ stocks belong to the same population based on nuclear and mitochondrial DNA (mtDNA) analyses. Four novel sperm whale mtDNA haplotypes were identified in animals from Australian waters. Levels of genetic diversity were low in Australian sperm whales but were similar to those previously reported for populations in the Indian and Pacific Oceans.
5. Given the genetic distinctiveness of sperm whales in Australian waters from other regions in the Pacific and Indian Oceans, and the lack of recovery in population numbers, further scientific studies are needed to increase our understanding of population dynamics and the effectiveness of threat management strategies in this species.

     

Effect of hydrodynamic dispersion on phosphatase reactions in a soil column

Columns of artificially-prepared soil crumbs were perfused with solutions of p-nitrophenyl phosphate and rates of hydrolysis of this substrate as catalyzed by soil phosphatase were measured. Hydrolysis proceeded by a zero-order or by a first-order reaction at high and low concentrations of substrate, respectively. Steady-state concentrations of substrate and products from the columns can be described essentially in terms of plug flow kinetics with but minor corrections for hydrodynamic dispersion. Values of the zero and first-order rate constants corrected for dispersion are 3 and 9 per cent greater, respectively, than those assuming plug flow kinetics. The apparent value of the first-order rate constant is about 70 percent higher than the true value because of electrostatic repulsion between the negatively-charged substrate and the soil particles.