Temporal response of the tiger salamander (<Emphasis Type="Italic">Ambystoma tigrinum</Emphasis>) to 3,000 years of climatic variation

Background  

Amphibians are sensitive indicators of environmental conditions and show measurable responses, such as changes in phenology, abundance and range limits to local changes in precipitation and temperature regimes. Amphibians offer unique opportunities to study the important ecological and evolutionary implications of responses in life history characteristics to climatic change. We analyzed a late-Holocene fossil record of the Tiger Salamander (Ambystoma tigrinum) for evidence of population-level changes in body size and paedomorphosis to climatic change over the last 3000 years.     

Amey: A multipurpose, russet-skinned potato cultivar for the Eastern United States

Amey is a late-maturing, russet-skinned, whitefleshed potato cultivar that yields more than Russet Burbank in most eastern United States potato production areas. Tubers of Amey are mostly oblong, occasionally long, with an evenly russetted skin. Tubers of Amey are smoother, more attractive, and have a much lower incidence of external defects than Russet Burbank. The specific gravity of Amey is equal to or greater than the specific gravity of Russet Burbank. French fries produced from Amey are lighter than or equal in color to those produced from Russet Burbank; however, tubers are frequently not long enough to satisfy the french fry industry. Baking and taste quality of Amey are excellent, and it has potential as a fresh market potato. Amey is resistant to race Rol of the golden nematode, powdery scab, and common scab. It is moderately susceptible to Verticillium wilt. It is susceptible to potato leafroll virus, late blight, and early blight.     

Comparison of three methods for assessing varietal differences in resistance to common scab disease (Streptomyces scabies) of potato

Summary Consistent varietal differences in scab severity were obtained when plants were grown in an open field or under a polythene tunnel in soil naturally infested withStreptomyces scabies, or in a glasshouse in pots filled with artificially inoculated sand. It was concluded that the glasshouse pot-inoculation technique would be the most suitable method to use in a breeding programme in which there are many clones to be tested, because a large number of plants can be grown in a small area under closely controled conditions.     

Loss of yield in potato selections infested with potato leafhoppers

The loss of yield resulting from infestation with potato leafhoppers,Empoasca fabae (Harris), was measured in a group of potato selections (Solatium tuberosum subsp.tuberosum). For 6 years in which 300 different clones were tested, the average loss of yield was 39%. The correlation over clones between level of infestation and percent hopperburn equaled 0.56; between level of infestation and loss of yield 0.36; and between percent hopperburn and loss of yield 0.41. Each coefficient is significant at P=0.01. Significant differences were found in levels of infestation and in percent hopperburn among the selections, but even those selections with the most resistant foliage had greatly reduced yields when infested. No selections were found that consistently produced a normal yield when infested with leafhoppers. The low level of infestation on the more resistant clones, however, may make chemical control at lower rates more effective.     

Effect of variety and location on the glycoalkaloid content of potatoes

Significant differences in tuber glycoalkaloid (TGA) content were found among five commercial varieties and B5141-6 grown at 39 different locations in 28 states. Line B5141-6 had the highest average TGA content, 29.3 mg/100 g in 1970 and 28.1 mg/100 g in 1971. Average TGA contents in 1970 of Kennebec, Russet Burbank, Katahdin, Irish Cobbler, and Red Pontiac were 9.7, 7.9, 7.9, 6.2, and 4.3 mg/100g, respectively. There were also significant location effects. Possible causes of high TGA levels are discussed.     

Consumption of 'extra' foods (energy-dense, nutrient-poor) among children aged 16-24 months from western Sydney, Australia

OBJECTIVE: This study evaluates the contribution of energy-dense, nutrient-poor 'extra' foods to the diets of 16-24-month-old children from western Sydney, Australia. DESIGN: An analysis of cross-sectional data collected on participants in the Childhood Asthma Prevention Study (CAPS), a randomised trial investigating the primary prevention of asthma from birth to 5 years. We collected 3-day weighed food records, calculated nutrient intakes, classified recorded foods into major food groups, and further classified foods as either 'core' or 'extras' according to the Australian Guide to Healthy Eating. SETTING: Pregnant women, whose unborn child was at risk of developing asthma because of a family history, were recruited from all six hospitals in western Sydney, Australia. Data for this study were collected in clinic visits and at participants' homes at the 18-month assessment. PARTICIPANTS: Four hundred and twenty-nine children participating in the CAPS study; 80% of the total cohort. RESULTS: The mean consumption of 'extra' foods was approximately 150 g day(-1) and contributed 25-30% of the total energy, fat, carbohydrate and sodium to the diets of the study children. 'Extra' foods also contributed around 20% of fibre, 10% of protein and zinc, and about 5% of calcium. Children in the highest quintile of 'extra' foods intake had a slightly higher but not significantly different intake of energy from those in the lowest quintile. However, significant differences were evident for the percentage of energy provided by carbohydrate and sugars (higher) and protein and saturated fat (lower). The intake of most micronutrients was also significantly lower among children in the highest quintile of consumption. The intake of 'extra' foods was inversely associated with the intake of core foods. CONCLUSIONS: The high percentage of energy contributed by 'extra' foods and their negative association with nutrient density emphasise the need for dietary guidance for parents of children aged 1-2 years. These preliminary data on commonly consumed 'extra' foods and portion sizes may inform age-specific dietary assessment methods.     

Biomineralization of gold: biofilms on bacterioform gold

Bacterial biofilms are associated with secondary gold grains from two sites in Australia. 16S ribosomal DNA clones of the genus Ralstonia that bear 99% similarity to the bacterium Ralstonia metallidurans-shown to precipitate gold from aqueous gold(III) tetrachloride-were present on all DNA-positive gold grains but were not detected in the surrounding soils. These results provide evidence for the bacterial contribution to the authigenic formation of secondary bacterioform gold grains and nuggets.