Distribution of minke whales in the Bellingshausen and Amundsen Seas (60°W–120°W), with special reference to environmental/physiographic variables

The relationship between the distribution of minke whales ( Balaenoptera acutorostrata ) in the Bellingshausen and Amundsen Seas (longitude between 60°W and 120°W), and environmental and physiographic variables (sea-surface temperature, sea-ice extension, and sea-floor-slope type), was studied to determine whether these environmental and physical factors affect the distribution and density of minke whales. The analysis was based on sightings data obtained from the 1989/90 and 1982/83 IWC/IDCR cruises. The mean sea-surface temperatures for comparable areas were significantly higher in 1989/90 (2.04°C) than in 1982/83 (1.12°C), and the area where the sea-surface temperature was greater than 1°C in the 1989/90 study was approximately twice that of the 1982/83 study. Additionally, during the surveys, the extent of the sea ice in 1989/90 was less than that in 1982/83, with the mean ice edge about 92.6 km (50 nautical miles; 1 nautical mile ≈1.852 km) farther south in 1989/90 than in 1982/83. This is consistent with the sea ice extent observed in winter, when the sea ice extent was less in 1989 than in 1982. The distribution of minke whales was substantially different between the two surveys, with the density and abundance of minke whales being greater in 1982/83 than in 1989/90. The warmer sea-surface temperatures, fewer cold-water intrusions, and the smaller extent of sea ice in 1989/90 may be related to the difference in distribution of minke whales from 1982/83, possibly owing to the shift in availability of prey.     

Some Opportunities for Pest Prevention by Ultra-low Volume Spraying

The needs of the modern system of integrated control, or pest management, are contrasted with those of the prevailing view that pest control is an individual responsibility. It is argued that a rational approach to pest management must be based on a knowledge of the scale on which it must be exercised. In the case of mobile insects the scale normally far exceeds the ecologically artificial boundaries represented by fields or private holdings. The argument is illustrated by the desert locust where numbers are reckoned in millions of millions and mobility in terms of hundreds and thousands of km., calling for international action, and the Tsetse fly where numbers are reckoned in less than 10 per ha. and mobility in terms of km. Experience in the control of paddy pests in Java is drawn on to show the contribution of synoptic survey to delimit the scale and time for appropriate action, followed by synchronous application of pesticides in achieving, through control of pests, yield increases in excess of what could be expected from small scale plot trials. The value of spraying at ultra-low volume rates is that it provides the means of achieving more or less synchronous application of pesticides on the scale demanded by the problem.     

PCR analysis of bisulfite-modified DNA to investigate developmental variation in micropropagated potatoes (Solanum tuberosum L.)

Summary Bisulfite modification of DNA from potato leaves showing juvenile and mature leaf morphologies and from leaves of autotrophic and heterotrophic microplants showing different morphologies was carried out to deaminate cytosine residues while leaving 5-methylcytosine residues intact. RAPD analysis of the DNA was then performed using selective primers; firstly, with a 50–70% GC content and subsequently with a 50–70% AT content which contained CG or CA 3' ends. Three of the 4 primers used detected band polymorphisms in the juvenile versus mature leaves and all four primers detected band polymorphisms in the autotrophic·versus heterotrophic in vitro leaf samples. These results indicate differences in methylation in the different paired DNA samples. The hypothesised increase in band numbers in the relatively less mature samples was confirmed for both the in vivo and in vitro leaf samples; a higher number of bands was amplified from the DNA of the leaves from heterotrophic cultures compared with those from autotrophic culture when the results for all primer sets were grouped. however, this trend did not apply to the results from all the individual primers. The application of this approach to the evaluation of in vitro protocols for potato micropropagation is discussed.     

Effects of artificial amendments in potting media on Orthosiphon aristatus growth and development

Artificial polyacrylamide gel (PAG) and urea-formaldehyde resin foam (UFRF) amendments are used for putative enhancement of soil physical properties, including increasing their water holding capacity (WHC). Effects were investigated of these two amendments alone and combined on growth and development of Orthosiphon aristatus (Cats’ Whiskers) grown in either composted pine bark or washed river sand, including under transient water deficit stress. UFRF and PAG were incorporated into these potting media substrates at recommended rates of 30% (v/v) and 0.1% (w/w), respectively. UFRF incorporation reduced bulk density and increased air-filled porosity of composted pine bark from 0.24 g cm⁻³ and 43.3% to 0.18 g cm⁻³ and 50.2%, respectively. UFRF also reduced bulk density of sand from 1.43 g cm⁻³ to 1.17 g cm⁻³ and increased its air-filled porosity from 18.5% to 25.3%. PAG slightly decreased bulk density of composted pine bark to 0.23 g cm⁻³ and also reduced sand bulk density to 1.32 g cm⁻³. Water content of composted pine bark and sand was increased by PAG addition from 47.6% and 27.7% to 51.0% and 34.2%, respectively. However, UFRF and/or PAG did not increase plant available water (PAW) in either composted pine bark or sand. PAW was 23.8% and 14.4%, 23.6% and 15.8%, 22.8% and 14.8%, and 25.2% and 17.8% for composted pine bark and sand controls, these two substrates amended with UFRF, these substrates amended with PAG, and these substrates with UFRF plus PAG, respectively. Neither shoot length nor number was increased by adding UFRF and/or PAG. Similarly, neither shoot fresh nor dry weight was increased by UFRF and/or PAG amendments. UFRF and, moreso, UFRF plus PAG slightly delayed the onset of wilting by 4–15 h in water deficit stressed O. aristatus compared to control and PAG alone in composted pine bark (experiment 1), but PAG did not. However, in experiment 2, UFRF and/or PAG did not delay wilting in either composted pine bark or sand. Thus, when incorporated at suppliers recommended rates, neither UFRF nor PAG conferred appreciable benefits for O. aristatus plant growth in either composted pine bark or sand potting media.     

Evaluation of Lactobacillus pentosus WE7 for prevention of diarrhea in neonatal foals

OBJECTIVE: To evaluate the efficacy of Lactobacillus pentosus WE7, an equine-origin organism with potentially beneficial in vitro properties, as a probiotic for prevention of neonatal diarrhea in foals. DESIGN: Randomized controlled clinical trial. ANIMALS: 153 foals. PROCEDURE: Foals were enrolled at 24 to 48 hours of age and randomly assigned to treatment or control groups. The treatment group received approximately 2 x 10(11) CFU of freeze-dried L. pentosus WE7 orally once daily for 7 days, whereas the control group received a placebo. Clinical monitoring was performed for 14 days. RESULTS: Probiotic administration was significantly associated with development of signs of depression, anorexia, and colic and the need for veterinary examination and treatment. Probiotic-treated foals also had more days of diarrhea, compared with the control group, although not significantly. In a multivariate model, probiotic administration was significantly associated with development of diarrhea and diarrhea plus additional clinical abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of L. pentosus WE7 did not prevent diarrhea; rather, it was associated with development of diarrhea and, most importantly, development of diarrhea plus additional clinical abnormalities and the need for veterinary intervention. The promising in vitro properties of L. pentosus WE7 were not evident in vivo. Results raise concern about the variety of untested probiotic products that are commercially available. Safety and efficacy testing needs to be performed for all potential equine probiotics.     

Suspected Clostridium difficile-associated hemorrhagic diarrhea in a 1-week-old elk calf

Clostridium difficile-associated diarrhea was suspected in a 1-week-old elk (Cervus elaphus) calf. The isolation of a toxigenic strain of C. difficile from a diarrheic fecal sample, along with exclusion of other enteropathogens, formed the basis of this presumptive diagnosis. Further study is indicated to evaluate the role of C. difficile in neonatal diarrhea in elk.