Male sex steroids are responsible for depressing macrophage immune function after trauma-hemorrhage

Recent studiessuggest beneficial effects of castration before soft tissue trauma andhemorrhagic shock on splenocyte immune functions. Nonetheless, itremains unknown whether this effect of testosterone depletion islimited to splenocytes or is a generalized effect on immune function.The present study was therefore carried out to determine whetherandrogen depletion before trauma-hemorrhage also has salutary effectson splenic and peritoneal macrophage as well as on Kupffer cellfunction, as indicated by interleukin (IL)-1 and IL-6 release. MaleC3H/HeN mice were castrated or sham-castrated 2 wk before theexperiment and were killed at 24 h after trauma-hemorrhage andresuscitation. Significant depression of macrophage IL-1 and IL-6release was only observed in sham-castrated mice, as opposed to normallevels of cytokine release from castrated animals after trauma-hemorrhage. In addition, only sham-castrated animals showed significantly increased levels of IL-6 release from Kupffer cells, which is believed to contribute to the systemic inflammatory response to trauma-hemorrhage. These observations suggest that the beneficial effects of androgen depletion before trauma-hemorrhage are not limitedto splenocyte immune functions but are more global in nature. Theseresults in surgically castrated animals suggest that androgen-blockingagents should be studied for their potential to reverse theimmunodepression associated with trauma-hemorrhage.

     

The prospects for peroxidase-based biorefining of petroleum fuels

Peroxidases have many potential uses for biotechnological processes. In this review, peroxidase-catalyzed reactions potentially applicable to the petroleum industry are described. Although peroxidases are attractive catalysts for desulfurization, aromatic oxidation and asphaltene transformation, there are important issues that must be overcome before any industrial application can be considered. The opportunities and challenges of enzymatic petroleum biorefining are documented and discussed, with emphasis on the available tools to design a biocatalyst with appropriate performance for the oil and other industries.     

Molecular characterization of InJR06, a class 1 integron located in a conjugative plasmid of Salmonella enterica ser. Typhimurium.

The presence of class 1, 2, and 3 integrons was investigated in four pediatric isolates of Salmonella enterica ser. Typhimurium (S. Typhimurium). A class 1 integron was detected in one S. Typhimurium strain, the only one that also showed resistance to various aminoglycoside antibiotics. This integron, called InJR06, and the aminoglycoside resistance determinants were located in pS06, a large (> or = 55 kb) conjugative plasmid. A single mobile cassette (encoding the aminoglycoside adenylyltransferase ANT(3')-Ia) was detected in the variable region of InJR06, while the architecture of the attI1 and attC sites was conserved.     

Testosterone: the culprit for producing splenocyte immune depression after trauma hemorrhage

Studies indicate that, whereas immune functions in males aredepressed, they are enhanced in females after trauma hemorrhage. Moreover, castration of male mice (i.e., androgen depletion) before trauma hemorrhage prevented the depression of cell-mediated immunity. Nonetheless, it remains unknown whether or not testosterone per se isresponsible for producing the immune depression. To study this, femaleC3H/HeN mice (n = 7 animals/group)were pretreated with 5-dihydrotestosterone (DHT) or vehicle for 19 days, then subjected to laparotomy (e.g., trauma) and hemorrhagic shock(blood pressure 35 ± 5 mmHg for 90 min) followed by fluidresuscitation or sham operation. Nontreated males underwent eithertrauma hemorrhage or sham operation. Twenty-four hours thereafter,splenocyte immune functions as well as plasma DHT, estradiol, andcorticosterone levels were measured. DHT-pretreated females hadsignificantly (P < 0.05) increasedDHT levels, comparable to those seen in males. Conversely, estradiollevels in such females were similar to control males. Splenocyteproliferation as well as interleukin-2 and interleukin-3 release werenot depressed in vehicle-treated females, whereas it was in DHT-treatedfemales after trauma hemorrhage, comparable to hemorrhaged males. Thushigh testosterone and/or low estradiol levels appear to beresponsible for producing splenocyte immune depression in males aftertrauma hemorrhage. Agents that block testosterone receptors or increaseestradiol levels may therefore be helpful in improving depressed immunefunctions in male trauma patients.

     

Competitive fitness in experimental populations of Drosophila willistoni

Experiments are reported in which genetically different strains of Drosophila willistoni compete with D. pseudoobscura. The competition was studied at three temperatures, 20°, 22°, and 25°C. The outcome of the competition depends on the genetic constitution of the competing species, but at 25° and 22°C D. willistoni flies are generally stronger competitors than D. pseudoobscura, while at 20°C D. pseudoobscura generally has a competitive advantage. There is a significant interaction between genotype and temperature; the strain RP3 is the weakest competitor of all D. willistoni strains at 22° and 25°C, but not at 20°C; the strain M18 is the best competitor at 20° and 22°C but not at 25°C.The performance of the four strains of D. willistoni was measured in two more ways. First we estimated their Darwinian fitness relative to other genotypes of the same species. Second, we measured the average population size of each strain in pure culture. There is no significant correlation between population size in pure culture and either competitive fitness or Darwinian fitness. There is, however, a strong positive correlation between Darwinian fitness and interspecific competitive fitness.It is pointed out that natural selection leads to an increase in the average Darwinian fitness of a population but not necessarily to an increase in its adaptedness to the environment. Yet the synthetic theory of evolution assumes that the genes and genotypes favored by natural selection are usually those which increase the adaptedness of their carriers to the environments where they live. The correlation between Darwinian fitness and adaptedness needs to be studied experimentally.This work was supported by NSF grant GB-12562 (International Biological Program), AEC contract AT-(30-1)-3096, and PHS Career Development Award K3GM 37265 to F. J. Ayala. The senior author's stay in New York was financed in part by Research Fellowship 2-12861 from the Panamerican Union.     

Global genetic diversity of Aedes aegypti

Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co‐occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub‐Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans‐Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.     

TRPML and lysosomal function

Mucolipin 1 (MLN1), also known as TRPML1, is a member of the mucolipin family. The mucolipins are the only lysosomal proteins within the TRP superfamily. Mutations in the gene coding for TRPML1 result in a lysosomal storage disorder (LSD). This review summarizes the current knowledge related to this protein and the rest of the mucolipin family.