Climate change,human impacts,and the resilience of coral reefs

The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.     

Phytoplankton community structure and the drawdown of nutrients and CO2 in the southern ocean

Data from recent oceanographic cruises show that phytoplankton community structure in the Ross Sea is related to mixed layer depth. Diatoms dominate in highly stratified waters, whereas Phaeocystis antarctica assemblages dominate where waters are more deeply mixed. The drawdown of both carbon dioxide (CO2) and nitrate per mole of phosphate and the rate of new production by diatoms are much lower than that measured for P. antarctica. Consequently, the capacity of the biological community to draw down atmospheric CO2 and transport it to the deep ocean could diminish dramatically if predicted increases in upper ocean stratification due to climate warming should occur.     

Molecular genotyping of multinational ovine and caprine Corynebacterium pseudotuberculosis isolates using pulsed-field gel electrophoresis

Caseous lymphadenitis (CLA) is a chronic, suppurative disease, with a worldwide distribution, caused by Corynebacterium pseudotuberculosis. The clinical manifestation of CLA is known to vary between different countries, and has been postulated to be due to differences in the strains present in these countries. Forty-two sheep and goat isolates of C. pseudotuberculosis from Australia, Canada, Eire, The Netherlands and Northern Ireland were characterized by pulsed-field gel electrophoresis (PFGE), biotyping, antimicrobial susceptibility, and production of phospholipase D. The PFGE-determined genotypes of this multicentric collection were then compared with representative ovine and caprine isolates from a previously published panel of PFGE profiles of United Kingdom isolates. Digestion with SfiI generated 16-18 bands in the 48.5 and 290 kb range, and differentiated four distinct pulsotypes amongst the 36 ovine and 6 caprine strains which displayed remarkable homogeneity. Based on these results, it would appear that the genome of C. pseudotuberculosis is highly conserved, irrespective of the country of strain origin.     

A column perfusion test to assess the kinetics of nutrient release by soluble,sparingly soluble and coated granular fertilizers

In recent years, innovations in fertilizer research have principally been in the design of products to supply more timely plant nutrients and mitigate detrimental losses to the environment. In the development of these fertilizers, a laboratory method to comparatively screen a large number of formulations for the rate of nutrient release is a critical first step in formulation optimization to significantly reduce time spent on pot and field trials, reducing costs considerably. Currently, given the absence of a standard laboratory method for all fertilizers, adaptions of a method for coated fertilizers from the International Organization for Standardization (2017) ISO 21263 and other column tests are being used which are often complex and/or require manual sampling which can be laborious, time consuming and costly. The method presented here evaluates the dynamic release in real time by continuously perfusing samples in columns utilizing an automated sample accumulation system for short‐term and long‐term release studies and eliminates the need for soil/sand packing of columns. Mass balance is accounted for by analysing the residue after dissolution and the amount released is expressed as a % of the total nutrient content in the product. This method is reliable, uncomplicated and cost‐effective and has been used to test uncoated soluble fertilizers, nanofertilizers, fertilizers with newly developed coating technologies and other slowly soluble fertilizers, to assess the effect of variables like coating chemistry and thickness, fertilizer composition or fertilizer particle size on release rate.     

Potent interaction between glucocorticoids and growth hormone-releasing factor in vivo

Administration of dexamethasone significantly enhanced the pituitary growth hormone response to growth hormone-releasing factor in intact as well as adrenalectomized rats. Thus the inhibitory effects of glucocorticosteroids on somatic growth which involve an interaction of these steroids and growth hormone at a peripheral level may also involve a modification of pathways within the central nervous system that regulate normal growth hormone secretion.     

Anaerobic soil disinfestation is an alternative to soil fumigation for control of some soilborne pathogens in strawberry production

Alternatives to soil fumigation are needed for soilborne disease control. The aim of this study was to test anaerobic soil disinfestation (ASD) as an alternative to soil fumigation for control of critical soilborne pathogens in Californian strawberry production. Controlled environment experiments were conducted at 25 and 15 °C to test different materials as carbon sources for ASD using soil inoculated with Verticillium dahliae. Field trials were conducted in three locations comparing ASD with 20 Mg ha^?1 rice bran (RB) against fumigated and untreated controls, steam, mustard seed meal and fish emulsion. In ASD‐treated soils, temperature and extent of anaerobic conditions were critical for control of V. dahliae, but multiple carbon inputs reduced inoculum by 80–100%. In field trials, ASD with RB provided control of a number of pathogens, and in three of four trials produced marketable fruit yields equivalent to fumigation. Little weed control benefit from ASD was found. ASD with RB also induced changes in the soil microbiome that persisted through the growing season. When equivalent yields were obtained, net returns above harvest and treatment costs with ASD RB were 92–96% of those with bed fumigation based on average prices over the previous 5 years. ASD can be a viable alternative for control of some soilborne pathogens. Growers are adopting ASD in California strawberry production, but research to determine optimal soil temperatures, anaerobicity thresholds and carbon sources for effective control of specific pathogens is needed.     

Characterization of AG-13, a Newly Reported Anastomosis Group of Rhizoctonia solani

ABSTRACT Rhizoctonia solani anastomosis group (AG)-13 was collected from diseased roots of field grown cotton plants in Georgia in the United States. Isolates of AG-13 did not anastomose with tester isolates of AG-1 through AG-12. Mycelium of all isolates of AG-13 were light brown but darkened as cultures aged. All isolates produced aerial mycelium. Concentric rings were visible after 3 to 4 days of growth but disappeared as cultures aged and darkened. Individual sclerotia were up to 1.5 mm in diameter, similar in color to the mycelium, and generally embedded in the agar. Clumps of sclerotia up to 5 mm in diameter were produced on the agar surface. All attempts to induce basidiospore production were unsuccessful. The 5.8S region of the rDNA from isolates of AG-13 was identical in length and sequence to isolates of all other AGs of R. solani. Length and sequence of the internal transcribed spacer (ITS) regions of rDNA from isolates of AG-13 were unique among AGs of R. solani. Similarity between AG-13 and other AGs of R. solani ranged from 68 to 85% for ITS region 1 and 85 to 95% for ITS region 2. Selected isolates of AG-13 caused minor or no damage to barley, cauliflower, cotton, lettuce, potato, and radish in laboratory or greenhouse studies.     

Outcome and subsequent fertility of sheep and goats undergoing cesarean section because of dystocia: 110 cases (1981-2001)

OBJECTIVE: To determine the outcome and subsequent fertility of sheep and goats undergoing a cesarean section because of dystocia. DESIGN: Retrospective study. ANIMALS: 85 sheep and 25 goats. PROCEDURE: Medical records were reviewed, and information was obtained on signalment, history, physical examination findings, anesthesia protocol, surgical technique, number of lambs or kids delivered, pre- and postoperative treatments, duration of hospitalization, and postoperative complications. Follow-up information was obtained through telephone conversations with owners. RESULTS: The proportion of sheep admitted to the veterinary teaching hospital during the study period that underwent a cesarean section (4.4%) was significantly higher than the proportion of goats that did (2.2%). Pygmy goats were overrepresented, compared with the hospital population. The most common reason for cesarean section was inadequate dilatation of the cervix. The most common surgical approach was via the left paralumbar fossa. Two hundred one lambs and kids were delivered, of which 116 were dead at delivery or died shortly afterward. Forty-two of the 65 dams with 1 or more dead fetuses had been in stage-2 labor for > 6 hours, and fetal death was significantly associated with a prolonged duration of dystocia. The most common complication following surgery was retained placenta (n = 49). Use of antimicrobials was associated with a lower rate of complications. All 16 dams that were rebred became pregnant and had no problems with dystocia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cesarean section is an effective method of resolving dystocia in sheep and goats and does not adversely affect subsequent fertility.