Seroprevalence of economically important viral pathogens in swine populations of Trinidad and Tobago,West Indies

The objective of this study was to evaluate the seroprevalence and identify the strains of swine influenza virus (SwIV), as well as the seroprevalence of porcine parvovirus (PPV), transmissible gastroenteritis virus (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine respiratory coronavirus (PRCV), porcine circovirus type 2 (PCV-2), and classical swine fever virus (CSFV) in pigs in Trinidad and Tobago (T&T). Blood samples (309) were randomly collected from pigs at farms throughout T&T. Serum samples were tested for the presence of antibodies to the aforementioned viruses using commercial ELISA kits, and the circulating strains of SwIV were identified by the hemagglutination inhibition test (HIT). Antibodies against SwIV were detected in 114 out of the 309 samples (37%). Out of a total of 26 farms, 14 tested positive for SwIV antibodies. HI testing revealed high titers against the A/sw/Minnesota/593/99 H3N2 strain and the pH1N1 2009 pandemic strain. Antibodies against PPV were detected in 87 out of the 309 samples (28%), with 11 out of 26 farms testing positive for PPV antibodies. Antibodies against PCV-2 were detected in 205 out of the 309 samples tested (66%), with 25 out of the 26 farms testing positive for PCV-2 antibodies. No antibodies were detected in any of the tested pigs to PRRSV, TGEV, PRCV, or CSFV.     

A kinetic study of the acetylation of cellulose, hemicellulose and lignin components in wood

The rates of acetylation of Deal, Larch, Southern Yellow Pine and Sitka Spruce using acetic anhydride in xylene have been measured and compared with the composition of the woods. Although these woods have similar macroscopic characteristics, the correlation between rate of acetylation and composition remains unclear, although the holocellulose may play a role in converting the hydrophilic hydroxyl groups to hydrophobic acetyl groups. The rate of acetylation of Larch at 373 K was insignificant but the other wood samples showed significant acetylation at this temperature. The activation energies for the acetylation process suggest that several routes may be involved.     

Application of a simulation model for assessing integration of smallholder shifting cultivation and sheep production in Yucatán, Mexico

Simulation models are effective tools to examine interactions between livestock, cropping systems, households, and natural resources. Our study objective was to use an integrated livestock and crop model to assess the outcomes from selected suites of management decisions observed in smallholder sheep-cropping systems of Yucatán, Mexico. The scenarios contrasted specialized systems versus mixed farming, and evaluated the outcomes of increased crop-livestock integration. Mixed enterprise scenarios involving sheep provided more income than specialized enterprises, and capitalized on a lower price of on-farm maize grain, efficient utilization of surplus labor, and availability of common land. Labor and management income was greatest for the unintegrated and partially integrated crop and livestock scenarios. It was more profitable for producers to sell excess grain and maize stover, and use common land to feed the livestock, suggesting that increased integration does not always result in improved outcomes. The results are consistent with a system not yet pushed to the point where integration is inevitable. For all sets of scenarios, the model structure was able to accommodate subtle management differences to produce appropriate biophysical, labor, and economic outcomes. We conclude there is potential to use similar model development methods to describe other crop-livestock systems, thus providing tools for learning, scenario analysis, and impact assessment.     

Preface—evaluating the response of critical zone processes to human impacts with sediment source fingerprinting

Journal of Soils and Sediments -     

Factors affecting the release of flavor encapsulated in carbohydrate matrixes

The effects of water content and temperature variation on the release of flavor components into the headspace over flavors, encapsulated by an extrusion process, in low water content carbohydrate matrixes is studied. The largest amounts of release occurred when the matrix was above its glass transition temperature, whether this was due to increased water content or elevated temperature. Under these conditions up to 70% of the sucrose in the matrix crystallized over a period of 10 days, as quantified using Fourier transform Raman spectroscopy. Smaller amounts of headspace release occurred when the water content of the encapsulated flavor system was decreased from 3. 5 to 3.1% w/w. Small amounts of release occurred from the "as prepared" materials, which were associated with the presence of small amounts of unencapsulated flavor oil with direct access to the headspace. It was concluded that release due to matrix permeability was relatively slow as compared with the above mechanisms.     

A longitudinal study of lymphocyte subsets in a cohort of cats naturally-infected with feline immunodeficiency virus

Despite the potential of feline immunodeficiency virus (FIV) as an animal model for human immunodeficiency virus (HIV) studies, the long term effects of naturally-occurring infection have not been determined. HIV infection causes an ongoing deterioration in immune function which directly correlates with disease, in particular acquired immunodefciency syndrome (AIDS). However, it is not known whether FIV-induced immunosuppression is progressive or related to the clinical condition. This study examined changes in lymphocyte subset numbers of serial samples, taken from cohorts of FIV-positive and FIV-negative cats over an 18-month period. FIV-positive cats were clinically staged as asymptomatic carriers (AC) or cats with AIDS-related complex (ARC), and FIV-negative cats matched and staged on the basis of similar diseases. During the course of the study, 4 FIV-positive cats developed AIDS, classed as the terminal stage of infection. There were no significant differences in the mean absolute numbers of any lymphocyte subset between the onset (to) and the completion (t18) of the study. Similarly there were no significant changes in subset numbers during the 18 months preceding the development of AIDS. While the study period was brief and the sample sizes small, it is postulated that FIV infection in Australia may not necessarily cause progressive immunodeficiency and that FIV-induced immunosuppression (as measured by subset analysis) may not be well correlated with the clinical status of the infected cat.     

Community proteomics of a natural microbial biofilm

Using genomic and mass spectrometry-based proteomic methods, we evaluated gene expression, identified key activities, and examined partitioning of metabolic functions in a natural acid mine drainage (AMD) microbial biofilm community. We detected 2033 proteins from the five most abundant species in the biofilm, including 48% of the predicted proteins from the dominant biofilm organism, Leptospirillum group II. Proteins involved in protein refolding and response to oxidative stress appeared to be highly expressed, which suggests that damage to biomolecules is a key challenge for survival. We validated and estimated the relative abundance and cellular localization of 357 unique and 215 conserved novel proteins and determined that one abundant novel protein is a cytochrome central to iron oxidation and AMD formation.     

THE PREVALENCE OF DIROFILARIA IMMITIS AND OTHER PARASITES IN URBAN POUND DOGS IN NORTH-EASTERN VICTORIA

SUMMARY The results of a survey investigating the prevalence of dirofilaria immitis and other helminth and protozoan infections in urban dogs in north-eastern Victoria are presented. D. immitis was detected in 2.7% of the general population (8.3% of dogs older than 2 years). Microfilariae of D. immitis were not detected in the peripheral circulation of 30% of dogs infected with the adult parasites. The most prevalent gastro-intestinal parasites were Dipylidium caninum 57%; Trichuris vulpis 41%; Toxocara canis 38%; and Uncinaria stenocephala 26%. The prevalence of T. canis in dogs less than one year of age was 73% and this decreased with increasing age. No Echinococcus granulosus adults were detected. Sarcocystis spp and Isospora ohioensis were the most commonly seen coccidians.     

How weed control and fertilisation influence tree physiological processes and growth at early establishment in an exotic F<Subscript>1</Subscript> hybrid pine plantation of subtropical Australia

Purpose

This study investigated how nitrogen (N) nutrition and key physiological processes varied under changed water and nitrogen competition resulting from different weed control and fertilisation treatments in a 2-year-old F₁ hybrid (Pinus elliottii Engelm var. elliottii?×?P. caribaea var. hondurensis Barr. ex Golf.) plantation on a grey podzolic soil type, in Southeast Queensland.

Materials and methods

The study integrated a range of measures including growth variables (diameter at ground level (DGL), diameter at breast height (DBH) and height (H)), foliar variables (including foliar N concentration, foliar δ¹³C and δ¹⁵N) and physiological variables (including photosynthesis (A_n), stomatal conductance (g_s), transpiration (E), intrinsic water use efficiency (WUE_i) (A/g_s) and xylem pressure potential (Ψ_XPP)) to better understand the mechanisms influencing growth under different weed control and fertilisation treatments. Five levels of weed control were applied: standard (routine), luxury, intermediate, mechanical and nil weed control, all with routine fertilisation plus an additional treatment, routine weed control and luxury fertilisation. Relative weed cover was assessed at 0.8, 1.1 and 1.6 years after plantation establishment to monitor the effectiveness of weed control treatments. Soil investigation included soil ammonium (NH₄ ⁺-N), nitrate (NO₃ ^?-N), potentially mineralizable N (PMN), gravimetric soil moisture content (MC), hot water extractable organic carbon (HWETC), hot water extractable total N (HWETN), total C, total N, stable C isotope composition (δ¹³C), stable N isotope composition (δ¹⁵N), total P and extractable K.

Results and discussion

There were significant relationships between foliar N concentrations and relative weed cover and between tree growth and foliar N concentration or foliar δ¹⁵N, but initial site preparation practices also increased soil N transformations in the planting rows reducing the observable effects of weed control on foliar δ¹⁵N. A positive relationship between foliar N concentration and foliar δ¹³C or photosynthesis indicated that increased N availability to trees positively influenced non-stomatal limitations to photosynthesis. However, trees with increased foliar N concentrations and photosynthesis were negatively related to xylem pressure potential in the afternoons which enhanced stomatal limitations to photosynthesis and WUE_i.

Conclusions

Luxury and intermediate weed control and luxury fertilisation positively influenced growth at early establishment by reducing the competition for water and N resources. This influenced fundamental key physiological processes such as the relationships between foliar N concentration, A _n, E, g_s and Ψ_XPP. Results also confirmed that time from cultivation is an important factor influencing the effectiveness of using foliar δ¹⁵N as an indicator of soil N transformations.

     

Effects of delmadinone acetate on pituitary-adrenal function, glucose tolerance and growth hormone in male dogs

Objective To characterise the effects of delmadinone acetate on the pituitary-adrenal axis, glucose tolerance and growth hormone concentration in normal male dogs and dogs with benign prostatic hyperplasia.
Design A prospective study involving nine normal male dogs and seven with prostatic hyperplasia.
Procedure Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperplasia at recommended dose rates (1.5 mg/kg subcuta-neously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. Blood concentrations of ACTH, cortisol, glucose, insulin and growth hormone were measured over 50 days. Intravenous glucose tolerance and ACTH response tests were performed before and after treatment in the nine normal animals.
Results A substantial suppression of basal and 2 h post-ACTH plasma cortisol secretion was demonstrated after one dose in all dogs given delmadinone acetate. Individual responses after the second and third administration varied between recovery in adrenal responsiveness to continued suppression. Plasma ACTH concentration was also diminished after one treatment. No effects were evident on glucose tolerance or serum growth hormone concentrations.
Conclusion Delmadinone acetate causes adrenal suppression from inhibition of release of ACTH from the pituitary gland. Treated dogs may be at risk of developing signs of glucocorticoid insufficiency if subjected to stressful events during or after therapy. Neither glucose intolerance nor hyper-somatotropism seems likely in male dogs given delmadinone acetate at the recommended dose rate, but the potential for excessive growth hormone secretion in treated bitches remains undetermined.