Cloning of aroG, the gene coding for phospho-2-keto-3-deoxy-heptonate aldolase(phe), in Escherichia coli K-12, and subcloning of the aroG promoter and operator in a promoter-detecting plasmid

Defective transducing phages carrying aroG, the structural gene for phenylalanine (phe)-inhibitable phospho-2-keto-heptonate aldolase (EC 4.1.2.15; previously known as 3-deoxy-D-arabinoheptulosonate-7-phosphate synthetase[phe]), have been isolated, and DNA from two of these phages has been used to construct a restriction map of the region from att lambda to aroG. A 7.6-kb PstI-HindIII fragment from one of these phages was cloned into pBR322 and shown to contain aroG. The location of aroG within the 7.6 kb was established by subcloning and Tn3 transpositional mutagenesis. A fragment carrying the aroG promoter and operator has been cloned into a high copy number promoter-cloning vector (pMC489), and the resulting aroGpo-LacZ' (alpha) fusion subcloned in a low copy number vector. Strains with this fusion on the low copy number vector exhibit negative regulation of beta-galactosidase expression by both phenylalanine and tryptophan and positive regulation by tyrosine in a tyrR+ background.     

Modelling multilocus selection in an individual‐based,spatially‐explicit landscape genetics framework

We implemented multilocus selection in a spatially‐explicit, individual‐based framework that enables multivariate environmental gradients to drive selection in many loci as a new module for the landscape genetics programs, CDPOP and CDMetaPOP. Our module simulates multilocus selection using a linear additive model, providing a flexible platform to evaluate a wide range of genotype‐environment associations. Importantly, the module allows simulation of selection in any number of loci under the influence of any number of environmental variables. We validated the module with individual‐based selection simulations under Wright‐Fisher assumptions. We then evaluated results for simulations under a simple landscape selection model. Next, we simulated individual‐based multilocus selection across a complex selection landscape with three loci linked to three different environmental variables. Finally, we demonstrated how the program can be used to simulate multilocus selection under varying selection strengths across different levels of gene flow in a landscape genetics framework. This new module provides a valuable addition to the study of landscape genetics, allowing for explicit evaluation of the contributions and interactions between gene flow and selection‐driven processes across complex, multivariate environmental and landscape conditions.     

Taste receptor activity and feeding behaviour reveal mechanisms of white spruce natural resistance to Eastern spruce budworm Choristoneura fumiferana

The pattern of feeding of Eastern spruce budworm Choristoneura fumiferana (Clem.) (Lepidoptera, Tortricidae) is compared on foliage from white spruce Picea glauca (Moench) Voss. (Pinaceae) trees previously determined to be susceptible and resistant to defoliation by budworm. No differences are observed in electrophysiological responses from taste sensilla to aqueous extracts of the two foliage types, nor is there a preference for either extract type in a choice test. Acetone extracts from the two foliage types are both preferred to a control sucrose solution, although neither elicits a preference relative to the other. These results suggest that there is no difference in phagostimulatory power of internal leaf contents of the two foliage types. Longer‐term observation of feeding behaviour in a no‐choice situation shows no difference in meal duration, confirming the lack of difference in phagostimulatory power. However, on average, intermeal intervals are twice as long on the resistant foliage, leading to an overall lower food consumption during the assay. This result suggests an anti‐digestive or toxic effect of the resistant foliage that slows behaviour and limits food intake. Previous research has shown that waxes of the resistant foliage deter initiation of feeding by the spruce budworm and that this foliage contains higher levels of tannins and monoterpenes. The data suggest that the resistant foliage contains a post‐ingestive second line of defence against the spruce budworm.     

Hepatic DNAJB9 Drives Anabolic Biasing to Reduce Steatosis and Obesity

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Population Dynamics,Root Penetration,and Feeding Behavior of Pratylenchus agilis in Monoxenic Root Cultures of Corn,Tomato, and Soybean

Population dynamics, rate of root penetration, and external root feeding behavior of Pratylenchus agilis (Pa) in monoxenic cultures of intact corn seedlings and root explants of corn, tomato, and soybean were studied. In descending order of suitability as hosts were I. O. Chief corn, Rutgers tomato, and Williams soybean. Soybean entries Kent, Pickett 71, PI 90763, and Essex were poor hosts. Numbers of eggs and vermiform Pa in the agar medium indicated total fecundity and host suitability. Agar, sand, or soil as support media did not appear to affect Pa root penetration, but the rate of corn root growth did. Whereas most vermiform Pa and eggs were in roots, substantial numbers appeared able to feed and complete their life cycle as ectoparasites on root epidermal cells and root hairs.     

Adiponectin Levels during Low‐ and High‐Fat Eucaloric Diets in Lean and Obese Women

Objective: Adiponectin influences insulin sensitivity (S_I) and fat oxidation. Little is known about changes in adiponectin with changes in the fat content of eucaloric diets. We hypothesized that dietary fat content may influence adiponectin according to an individual's S_I. Research Methods and Procedures: We measured changes in adiponectin, insulin, glucose, and leptin in response to high‐fat (HF) and low‐fat (LF) eucaloric diets in lean (n = 10) and obese (n = 11) subjects. Obese subjects were further subdivided in relation to a priori S_I. Results: We found significantly higher insulin, glucose, and leptin and lower adiponectin in obese vs. lean subjects during both HF and LF. The mean group values of these measurements, including adiponectin (lean, HF 21.9 ± 9.8; LF, 20.8 ± 6.6; obese, HF 10.0 ± 3.3; LF, 9.5 ± 2.3 ng/mL; mean ± SD), did not significantly change between HF and LF diets. However, within the obese group, the insulin‐sensitive subjects had significantly higher adiponectin during HF than did the insulin‐resistant subjects. Additionally, the change in adiponectin from LF to HF diet correlated positively with the obese subjects’ baseline S_I. Discussion: Although in lean and obese women, group mean values for adiponectin did not change significantly with a change in fat content of a eucaloric diet, a priori measured S_I in obese subjects predicted an increase in adiponectin during the HF diet; this may be a mechanism that preserves S_I in an already obese group.