An outbreak of Potato spindle tuber viroid in tomato is linked to imported seed

In 2011, an outbreak of the quarantine-regulated pathogen Potato spindle tuber viroid (PSTVd) occurred in a commercial glasshouse-grown tomato crop in Queensland, Australia. Phylogenetic studies showed that the genotype of this isolate grouped in a cluster of PSTVd genotypes from tomato and Physalis peruviana, and exhibited an interesting mutation (U₂₅₇→A) that has previously been linked to lethal symptom expression in tomato. Transmission studies showed that the viroid could be mechanically transmitted from crushed fruit sap, but not from undamaged fruits. A low rate of asymptomatic infection was determined for plants in the affected glasshouse, demonstrating the efficacy of using symptoms to detect PSTVd infections in tomato. No PSTVd infections were detected in solanaceous weeds located outside of the infected glasshouse, excluding them from playing a role in the viroid epidemiology. Monitoring and subsequent testing of new tomato crops grown in the facility demonstrated successful eradication of the pathogen. A trace-back analysis linked the outbreak of PSTVd to an infected imported tomato seed-lot, indicating that PSTVd is transmitted internationally through contaminated seed.     

Semen Characteristics in a Sub‐Fertile Arabian Stallion with Idiopathic Teratospermia

A 5‐year‐old Arabian stallion was managed for breeding with fresh/extended semen during a period of 8 months with a resulting per cycle pregnancy rate of 26.3%. The stallion was in good health and no abnormalities of the reproductive tract were observed. Evaluation of several ejaculates revealed that sperm production and semen quality were mostly unchanged during the period of evaluation, that sperm production was normal and that semen quality was extremely poor. The most prevalent sperm defects were abnormal heads and mid‐pieces. Most abnormal heads were microcephalic and/or tapered and considerable variation in sperm head dimensions within and among ejaculates was observed. A unique defect characterized by swollen/roughened mid‐piece caused by accumulation of cytoplasmic‐like material and abnormal mitochondrial sheath was observed. Nuclear vacuoles, acrosome defects, and teratoids were also prevalent and most sperm presented multiple abnormalities. The absence of any clear cause or any signs of testicular degeneration, combined with normal sperm production, and constant abnormal sperm production suggest an inherent, congenital disturbance of spermatogenesis as the cause of teratospermia in this case.     

Nutritional myopathy in goats

A nutritional myopathy in unweaned fibre goats aged 2 to 4 mths is described in 3 flocks from the tablelands of New South Wales. Clinically affected animals were illthrifty and in circulatory failure prior to being found dead. At necropsy, there was pronounced ascites, pulmonary congestion and marked mottling of the liver. Chalky white streaks and patches were obvious in the myocardium, particularly in the right ventricular wall. Skeletal muscles varied from grossly normal to generally pale. Histologically, the myocardium exhibited areas of severe acute myonecrosis with mineralisation and adjoining areas of phagocytosis and fibrosis. In 2 of 3 flocks, some skeletal muscles showed a mild subacute myopathy. Marked hepatic congestion extended to periacinar haemorrhage and necrosis in some areas. Dietary imbalances of selenium, vitamin E and polyunsatured fatty acids were probable factors in the pathogenesis of the condition.     

Effects of zeranol implants on post-castration response in calves

SUMMARY Suckling and yearling calves were surgically castrated and one half of each group implanted with 36 mg zeranol at time of castration. Both treated and control cattle of each class were maintained as a group and evaluated for swelling of the scrotum, inflammation and healing, plasma prostaglandin levels and weight gain. Swelling and inflammation of the scrotum were less in treated suckling calves than in controls at both 7 and 14 d after castration, though this difference was not statistically significant. In yearlings at 7 d after castration, treated cattle had more swelling than controls; however at 14 d, treated cattle had less swelling and inflammation with only one treated yearling having an open scrotal wound versus 6 (P <.03) in the control group. Plasma prostaglandin levels as indicated by plasma malondialdehyde increased from d 0 to 14; however no significant treatment differences were observed for either age group. Suckling calves treated with zeranol gained 9.79 kg more (P <.03) than non-treated calves during the 97 d of trial while the yearlings treated with zeranol gained 16.78 kg more (P <.01) than controls during 102 d. It is concluded from the increased growth and reduced scrotal swelling and inflammation in treated cattle that zeranol implantation could possibly have a beneficial effect in improving the healing process after castration.     

Induction of heat stress in beef cattle by feeding the ergots of Claviceps purpurea

Two groups of 4 Hereford steers were housed in a controlled environment room and exposed to simulated high summer temperatures. Both groups were fed a barley grain and hay diet ad libitum. The barley in one diet contained 0.5% w/w ergots of Claviceps purpurea. Within one week of feeding the ergot diet mean rectal temperature was significantly elevated (P less than 0.05) each afternoon (up to 41 degrees C) but returned to normal overnight. Elevated rectal temperature was accompanied by other signs of heat stress, reduced feed intake, body weight loss and depression or serum prolactin concentration. Symptoms disappeared within 1 week of ceasing to feed the ergot diet.     

Spatial Response of Mammals to Late Quaternary Environmental Fluctuations

Analyses of fossil mammal faunas from 2945 localities in the United States demonstrate that the geographic ranges of individual species shifted at different times, in different directions, and at different rates in response to late Quaternary environmental fluctuations. The geographic pattern of faunal provinces was similar for the late Pleistocene and late Holocene, but differing environmental gradients resulted in dissimilar species composition for these biogeographic regions. Modern community patterns emerged only in the last few thousand years, and many late Pleistocene communities do not have modern analogs. Faunal heterogeneity was greater in the late Pleistocene.     

The Interdependence of Deformational and Thermal Processes in Mountain Belts

Crustal temperatures within collisional orogens are anomalously high compared with temperatures at comparable depths in stable continents, which is evidence of thermal processes that are fundamental to orogenesis. These temperatures can be explained by the redistribution of crust enriched in heat-producing elements through the accretion of crust from the down-going plate to the upper plate and surface erosion. With the use of geologically reasonable rates, the model results predict high temperatures (over 600°C) and inverted upper-plate geotherms (about 100°C over 20 kilometers) at shallow depths (20 to 40 kilometers) by 25 to 35 million years after collision. This study emphasizes the interdependence of deformational, surficial, and thermal processes.