Naturally occurring and experimental Stachys arvensis (staggerweed) toxicity in lambs in New Zealand

Stachys arvensis (staggerweed) is a common, widely distributed weed of cultivated and waste land with the potential to intoxicate sheep. Two naturally occurring outbreaks of suspected staggerweed toxicity in the lower North Island were investigated. Affected lambs had been recently moved onto staggerweed-contaminated Brassica spp. crops. In total, 150/1,200 (13%) lambs developed hindlimb paresis, a fine generalised muscular tremor, and hunched posture. When forced to move, many became recumbent. Most lambs recovered within 48 h of removal from staggerweed, although a few developed clinical signs again when transported 2–3 weeks later. Grossly, affected lambs had large amounts of staggerweed plant material and seeds within the rumen. Histopathology showed mild, multifocal degeneration of the white matter tracts of the central nervous system (CNS), most commonly in the ventral funiculi of the spinal cord, and acute, mild to moderate, multifocal degeneration of skeletal muscles. Creatine kinase (CK) activity in serum was mildly to markedly elevated in affected lambs. In a feeding trial, ten 10-month-old Romney lambs were randomly assigned to equal treatment and control groups. Treated lambs were drenched with a liquid extract of staggerweed once daily for 7 days. Three of five treated lambs developed mild exercise intolerance, and 1/5 displayed mild paresis of the hindlimbs, slightly crouched hindlimb stance, and shortened gait, on days 6 and 7. Histologically, 4/5 treated lambs had degeneration in white matter tracts of the CNS, indistinguishable from those seen in the lambs in the outbreak, and in 1/5 lambs there was scattered regeneration of skeletal muscle. CK activity in serum in treated lambs was not significantly higher than that in control lambs. None of the control lambs developed significant clinical signs, histological changes or increases in CK activity in serum. The clinical signs and lesions observed in both the outbreaks and feeding trial were similar to those previously described in studies in Australia, with the exception that myodegeneration was more prominent in the outbreaks in New Zealand. Further characterisation of the pathogenesis of staggerweed toxicity and its potential role as a food safety hazard will be facilitated through identification of the toxic principle(s).     

Quackgrass (Elytrigia repens) managed as a cover crop in herbicide-resistant silage corn

The groundcover levels after corn ( Zea mays L.) silage harvest are rarely adequate to prevent soil erosion, but most corn-growers do not plant cover crops due to time and cost limitations. Herbicide-resistant corn hybrids provide opportunities to control weeds and to utilize cover crops in previously unexplored combinations. Field studies were conducted in 1999 and 2000 at Dryden and Valatie, New York, USA, to determine the potential for managing existing quackgrass ( Elytrigia repens [L.] Nevski) as a cover crop in herbicide-resistant silage corn. Three isolines of the corn hybrid, DKC493, were treated with glyphosate, glufosinate, primisulfuron, nicosulfuron or sethoxydim. Averaged over all site–years, the corn silage yields with glufosinate were similar to those with glyphosate. Glufosinate also resulted in a quackgrass ground cover greater than the 30% threshold for preventing soil erosion. Quackgrass could be managed as a perennial cover crop in silage corn–perennial forage dairy rotations in north-eastern USA.     

Comparison of the Johne''s absorbed EIA and the complement-fixation test for the diagnosis of Johne''s disease in cattle

A commercially available absorbed ELISA for the diagnosis of Johne's disease (JD) (paratuberculosis) in cattle, the Johne's Absorbed EIA, was compared with the conventional complement-fixation test (CFT) used in Australia. Stored plasma from 3 Victorian dairy herds with a history of JD, sera from specimens submitted from animals showing clinical signs of JD and sera from the US National Repository for Paratuberculosis Specimens were used to determine the sensitivity of each test. The EIA detected 48.8% of 43 Australian animals with subclinical JD, while the CFT detected only 12 (21.4%) of 56 subclinically affected cattle. Of 150 subclinically infected US cattle, the EIA detected 47.3% and the CFT detected 52.0%. The EIA detected 59.7% of animals which at the time of sampling were shedding Mycobacterium paratuberculosis in their faeces, but showed no clinical signs of JD, while the CFT detected 57.3%. The EIA correctly identified 88.2% of 136 histologically confirmed clinical cases, and the CFT detected 83.4%. The specificity of each test was determined by testing sera collected at slaughter from animals residing in a known JD-free area of Australia, and from samples from the US National Repository of Paratuberculosis Specimens collected from certified-free herds in Wisconsin. The EIA was found to have a specificity of 99.8% when 998 Australian animals were used as the test population, and 99.0% when 196 US animals were used. The specificity of the CFT using Australian samples was 96.9% and 95.2% using American samples.     

Waist circumference as a determinant of hypertension and diabetes in Brazilian women: a population-based study

OBJECTIVE: To evaluate the role of central adiposity, as evaluated by the measurement of waist circumference (WC), as an independent risk factor for hypertension and type 2 diabetes mellitus in the setting of a developing country. DESIGN: Population-based, cross-sectional study. SETTING: A medium-sized town in southern Brazil. PARTICIPANTS: One thousand and ninety-five non-pregnant women, 20 to 69 years old, recruited by cluster random sampling between 1999 and 2000. Their mean WC was 85.3 cm (standard deviation 13.9 cm) and 23.3% (n=255) were obese (body mass index >30 kg m(-2)). The prevalence of hypertension and diabetes was 25.6% (n=280) and 6.2% (n=68), respectively. RESULTS: The risks of hypertension and diabetes were directly related to WC measurement. Women with WC>80 cm had increased risk of hypertension (odds ratio (OR)=6.2, P<0.001). The association remained significant (OR=1.04 per cm increase in WC, P=0.02) after adjusting for confounders. The effect of WC on diabetes was modified by age. The effect was stronger in women younger than 40 years old (OR=12.7, P=0.016) than in those over 40 years old (OR=2.8, P=0.013). In the multivariate analysis, the odds ratio was 5.7 (P=0.12) in those under 40 years old and 2.8 (P=0.008) in older women. CONCLUSIONS: Waist circumference is an independent determinant for hypertension and diabetes in women in this population. The stronger association between WC and diabetes in younger women suggests that the validity of this indicator to assess abdominal adiposity is age-specific. Further studies should validate the usefulness of WC measurement in different age groups.     

Nitric Oxide and Superoxide Anion Production During Heparin‐Induced Capacitation in Cryopreserved Bovine Spermatozoa

The aim of this work was to quantify NO, O₂^? and ONOO^? production during heparin‐induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin‐dependent capacitation, O₂ uptake, and NO production. Conversely, O₂^? production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a threefold increase in O₂ consumption (5.9 ± 0.6 nmol/min × 10⁷ cells), an enhancement in NO release (1.1 ± 0.2 nmol/min × 10⁷ cells), and a five‐fold increase in O₂^? production (1.3 ± 0.07 nmol/min × 10⁷ cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O₂^? generation and the second‐order rate constant of the reaction between these species. To conclude, heparin‐induced capacitation of cryopreserved bovine spermatozoa activates (i) mitochondrial O₂ uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O₂^? production by a membrane‐bound NAD(P)H oxidase. The products of both enzymes are released to the extracellular space and could be involved in the process of sperm capacitation.     

Cosmic rays: the highest-energy messengers

The origin of the most energetic particles ever observed, cosmic rays, will begin to be revealed in the next few years. Newly constructed ultrahigh-energy cosmic ray observatories together with high-energy gamma-ray and neutrino observatories are well positioned to unveil this mystery before the centenary of their discovery in 2012. Cosmic ray sources are likely to involve the most energetic phenomena ever witnessed in the universe.     

Helminthosporiella stilbacea associated with African oil palm (Elaeis guineensis) in Brazil

African oil palm (Elaeis guineensis Jacq.) is considered the most productive oleaginous crop due to its high oil production per hectare. In April 2015, E. guineensis leaves showing elliptical necrotic spots with yellowish halo were observed in a commercial plantation in Moju, Pará state, Brazil. A synematous fungus was consistently observed associated with the necrotic spots. The aim of this study was to identify this fungus associated with E. guineensis in Brazil. Based on morphology and DNA sequence data of the internal transcribed spacer rDNA, the fungus was identified as Helminthosporiella stilbacea. Helmintosporiella stilbacea has been reported associated with leaf spots on E. guineensis in Africa, Ghana, Sudan and Zambia. To the best of our knowledge, this is the first report of H. stilbacea associated with E. guineensis in Brazil.