Association of disease with isolation and virulence of Rhodococcus equi from farm soil and foals with pneumonia

OBJECTIVE: To determine whether isolation and virulence of Rhodococcus equi from soil and infected foals are associated with clinical disease. DESIGN: Cross-sectional and case-control study. SAMPLE POPULATION: R equi isolates from 50 foals with pneumonia and soil samples from 33 farms with and 33 farms without a history of R equi infection (affected and control, respectively). PROCEDURE: R equi was selectively isolated from soil samples. Soil and clinical isolates were evaluated for virulence-associated protein antigen plasmids (VapA-P) and resistance to the beta-lactam antibiotics penicillin G and cephalothin. Microbiologic cultures and VapA-P assays were performed at 2 independent laboratories. RESULTS: VapA-P was detected in 49 of 50 (98%) clinical isolates; there was complete agreement between laboratories. Rhodococcus equi was isolated from soil on 28 of 33 (84.8%) affected farms and 24 of 33 (72.7%) control farms, but there was poor agreement between laboratories. Virulence-associated protein antigen plasmids were detected on 14 of 66 (21.2%) farms by either laboratory, but results agreed for only 1 of the 14 VapA-P-positive farms. We did not detect significant associations between disease status and isolation of R equi from soil, detection of VapA-P in soil isolates, or resistance of soil isolates to beta-lactam antibiotics. No association between beta-lactam antibiotic resistance and presence of VapA-P was detected. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of soil microbiologic culture and VapA-P assay results, it is not possible to determine whether foals on a given farm are at increased risk of developing disease caused by R equi.     

Molecular basis of the shish-kebab morphology in polymer crystallization

In the rich and long-standing literature on the flow-induced formation of oriented precursors to polymer crystallization, it is often asserted that the longest, most extended chains are the dominant molecular species in the "shish" of the "shish-kebab" formation. We performed a critical examination of this widely held view, using deuterium labeling to distinguish different chain lengths within an overall distribution. Small-angle neutron-scattering patterns of the differently labeled materials showed that long chains are not overrepresented in the shish relative to their concentration in the material as a whole. We observed that the longest chains play a catalytic role, recruiting other chains adjacent to them into formation of the shish.     

Gender disparity in liver cancer due to sex differences in MyD88-dependent IL-6 production

Hepatocellular carcinoma (HCC), the most common liver cancer, occurs mainly in men. Similar gender disparity is seen in mice given a chemical carcinogen, diethylnitrosamine (DEN). DEN administration caused greater increases in serum interleukin-6 (IL-6) concentration in males than it did in females. Furthermore, ablation of IL-6 abolished the gender differences in hepatocarcinogenesis in mice. DEN exposure promoted production of IL-6 in Kupffer cells (KCs) in a manner dependent on the Toll-like receptor adaptor protein MyD88, ablation of which also protected male mice from DEN-induced hepatocarcinogenesis. Estrogen inhibited secretion of IL-6 from KCs exposed to necrotic hepatocytes and reduced circulating concentrations of IL-6 in DEN-treated male mice. We propose that estrogen-mediated inhibition of IL-6 production by KCs reduces liver cancer risk in females, and these findings may be used to prevent HCC in males.     

Insect sex-pheromone signals mediated by specific combinations of olfactory receptors

We describe two male-specific olfactory receptors (ORs) in the silk moth, Bombyx mori, that are mutually exclusively expressed in a pair of adjacent pheromone-sensitive neurons of male antennae: One is specifically tuned to bombykol, the sex pheromone, and the other to bombykal, its oxidized form. Both pheromone ORs are coexpressed with an OR from the highly conserved insect OR subfamily. This coexpression promotes the functional expression of pheromone receptors and confers ligand-stimulated nonselective cation channel activity. The same effects were also observed for general ORs. Both odorant and pheromone signaling pathways are mediated by means of a common mechanism in insects.     

Experimental studies on SO2 injuries in higher plants III: Inhibitory effect of suite ion on 14 CO 2 fixation

Photosynthesis decreases reversibly in plants exposed to SO₂. Photosynthesis recovers when the exposure to SO₂ is discontinued. Inactivation of a photosynthetic enzyme, ribulose-1,5-diphosphate carboxylase, by sulfonation of its SH groups was investigated as a cause of the reversible reduction of photosynthesis. The relationship between the sulfite ion concentration in the reaction mixture and ¹⁴CO₂ fixation catalized by the enzyme which was prepared from alfalfa leaves was explored by using radioactive NaHCO₃. About 50% and 85% inhibitions of ¹⁴CO₂ fixation were observed at 3 × 10^?3 M and 3 × 10^?2 M concentration of sulfite ion in the reaction mixture, respectively. The accumulation of 3 × 10^?4 M sulfite ion on the reaction site of the enzyme involved in the plants which were exposed to SO₂ could considerably reduce the CO₂ assimilation of the plant.     

Can Shifting Cultivation on Acid Soils in the Southeast Asia Be Sustainable in the Future? A Case Study in Northern Laos

Sustainability of the local shifting cultivation practice in the mountainous region of Northern Laos was investigated. Due to low fertility of the soils derived from shale and its strongly weathered and acidic nature in the eastern side of the Nam Khan River watershed, shortening of the fallow period to produce enough amount of upland rice for the local population would not be sustainable any more. On the other hand, the eroded materials from limestone range were added to the soils in the western side of watershed which made the soil more fertile. Based on the calculated population capacity by Carneiro's equation, a system with 2- or 3-year fallow for 1-year cultivation can be the maximum to afford the current population. To make the shifting cultivation system more sustainable, introduction of fallow system with a tree species, paper mulberry ( Broussonetia papyrifera ) could be a good option to be proposed.     

High-resolution mapping of the nud locus controlling the naked caryopsis in barley

The hulled or naked caryopsis character of barley is an important agronomic trait because of the direct link to its use. A single recessive gene, nud, located on the long arm of chromosome 7H, controls the naked caryopsis character. Previously, linked amplified fragment length polymorphism (AFLP) bands from bulked segregant analysis were screened, and the nud gene was mapped in a population of 151 F₂ plants. In the present study, the aim was to construct a high‐resolution map of the nud gene towards its positional cloning. Two AFLP bands were converted into sequence‐characterized amplified region (SCAR) markers (sKT5 and sKT9), and a previously reported SCAR marker sKT3 was improved for more reliable detection of polymorphism. A total of 2380 segregants derived from five cross‐combinations were analysed, and the nud gene was flanked by sKT3 and sKT9, at the 0.6‐cM proximal and the 0.06‐cM distal side, respectively. The SCAR markers developed in this study should be useful for marker‐assisted selection in naked barley breeding employing crosses between naked and hulled accessions.