Significance of Pseudomonas aeruginosa in Sputum

Pseudomonas aeruginosa was isolated from the sputum of 63 patients. In 34 the organism was a commensal, in 14 it was causing chronic suppuration, and in 10 had interfered with antibiotics directed against other organisms and was thus indirectly pathogenic. In five patients, all of whom died, the organism could have been acting as an acute pathogen. Attempts should be made to determine the nature of the organism''s pathogenicity in a given patient and appropriate therapy withheld or administered accordingly.     

Rearing Environment Affects the Brain Size of Guppies: Lab-Reared Guppies have Smaller Brains than Wild-Caught Guppies

Animals bred for captivity often have smaller brains and behave differently than their wild counterparts. These differences in brain size have been attributed to genetic changes resulting from, for example, inbreeding depression and pleiotropic effects of artificial selection for traits such as docility. A critical question, though, is whether these differences in brain size are due to plastic responses to the environment, not just genetic changes. We observed a large reduction in brain size in first generation, lab-reared female guppies compared with wild-caught ones (19% smaller telencephalon, 17% smaller optic tectum). We then reared first-generation, lab-born guppies in environments varying in spatial complexity and size in an attempt to isolate factors that might increase brain size and change temperament, but no significant differences in phenotype were observed. The results of these experiments show that, although the environmental factors responsible for the effect have not been found, even first generation lab-reared individuals can have smaller brains than wild individuals.     

Regulatory and Functional Diversity of Methylmercaptopropionate Coenzyme A Ligases from the Dimethylsulfoniopropionate Demethylation Pathway in Ruegeria pomeroyi DSS-3 and Other Proteobacteria

The organosulfur compound dimethylsulfoniopropionate (DMSP) is produced by phytoplankton and is ubiquitous in the surface ocean. Once released from phytoplankton, marine bacteria degrade DMSP by either the cleavage pathway to form the volatile gas dimethylsulfide (DMS) or the demethylation pathway, yielding methanethiol (MeSH), which is readily assimilated or oxidized. The enzyme DmdB, a methylmercaptopropionate (MMPA)-coenzyme A (CoA) ligase, catalyzes the second step in the demethylation pathway and is a major regulatory point. The two forms of DmdB present in the marine roseobacter Ruegeria pomeroyi DSS-3, RPO_DmdB1 and RPO_DmdB2, and the single form in the SAR11 clade bacterium “Candidatus Pelagibacter ubique” HTCC1062, PU_DmdB1, were characterized in detail. DmdB enzymes were also examined from Ruegeria lacuscaerulensis ITI-1157, Pseudomonas aeruginosa PAO1, and Burkholderia thailandensis E264. The DmdB enzymes separated into two phylogenetic clades. All enzymes had activity with MMPA and were sensitive to inhibition by salts, but there was no correlation between the clades and substrate specificity or salt sensitivity. All Ruegeria species enzymes were inhibited by physiological concentrations (70 mM) of DMSP. However, ADP reversed the inhibition of RPO_DmdB1, suggesting that this enzyme was responsive to cellular energy charge. MMPA reversed the inhibition of RPO_DmdB2 as well as both R. lacuscaerulensis ITI-1157 DmdB enzymes, suggesting that a complex regulatory system exists in marine bacteria. In contrast, the DmdBs of the non-DMSP-metabolizing P. aeruginosa PAO1 and B. thailandensis E264 were not inhibited by DMSP, suggesting that DMSP inhibition is a specific adaptation of DmdBs from marine bacteria.     

A Scoping Analysis of Peer-Reviewed Literature About Linkages Between Aquaculture and Determinants of Human Health

For many of the world’s poor, aquatic products are critical for food security and health. Because the global population is increasing as wild aquatic stocks are declining, aquaculture is an increasingly important source of aquatic products. We undertook a scoping review of the English-language peer-reviewed literature to evaluate how the research community has examined the impacts of aquaculture on four key determinants of human health: poverty, food security, food production sustainability, and gender equality. The review returned 156 primary research articles. Most research (75%) was focused in Asia, with limited research from Africa (10%) and South America (2%). Most research (80%) focused on freshwater finfish and shrimp production. We used qualitative content analysis of records which revealed 11 themes: famer income; the common environment; shared resources; integrated farming/ polyculture; employment; extensive vs. intensive production; local vs. distant ownership; food security; income equity; gender equality; and input costs. We used quantitative content analysis of records and full-text publications about freshwater finfish and shrimp aquaculture to record the frequency with which themes were represented and the positive or negative impacts of aquaculture associated with each theme. Scatter plots showed that no theme was identified in more than half of all articles and publications for both production types. Farmer income was a theme that was identified commonly and was positively impacted by both shrimp and fresh water finfish aquaculture. Polyculture, employment, and local ownership were identified less often as themes, but were also associated with positive impacts. The common environment and shared resources were more common themes in shrimp aquaculture than freshwater finfish aquaculture research, while polyculture and local ownership were more common themes in freshwater finfish aquaculture than shrimp aquaculture. Gender equality, employment, and food security were themes found in a lower percentage of records than full-text publications for both production types.     

Mice defective in the mismatch repair gene Msh2 show increased predisposition to UVB radiation-induced skin cancer

Mice defective in the mismatch repair (MMR) gene Msh2 manifest an enhanced predisposition to skin cancer associated with exposure to UVB radiation. This predisposition is further heightened if the mice are additionally defective for the nucleotide excision repair gene Xpc. To test the hypothesis that the predisposition of Msh2 mutant mice to skin cancer reflects a mutator phenotype associated with increased proliferation of skin cells following exposure to UV radiation, Msh2 mutant mice were exposed to the tumor promoter TPA. Such mice showed a robust proliferative response in the skin, but did not manifest evidence of dysplasia or neoplasia. We conclude that the predisposition of Msh2 mice to UVB radiation-induced skin cancer reflects an interaction between the processes of mismatch repair and some other excision repair mode, the exact nature of which remains to be established.     

Identification and quantitation of human amniotic fluid components using capillary zone electrophoresis

A capillary electrophoresis method was used to measure albumin, immunoglobulin G (IgG), transferrin, and uric acid in 230 amniotic fluid (AF) samples collected at 15.15 ± 0.06 weeks gestation. Species were quantified by external calibration using thiamine as internal standard. All major components were detected within 10 min. Migration time reproducibility was 3.0% relative standard deviation (RSD) and normalized peak areas were 12% RSD or better at 190 nm from 81 measurements of a pooled AF sample. The separation profile was not affected by 10 h of storage at room temperature or by 10 freeze-thaw cycles, suggesting that frozen AF samples are suitable for protein biomarker studies.