Invasive migration of a mainland rodent to santa catalina island and its effect on the endemic species <Emphasis Type="Italic">Peromyscus slevini</Emphasis>

Santa Catalina Island has an endemic mouse, Peromyscus slevini, which is the only native rodent species on the island. However, specimens of P. fraterculus have been recorded on the island. P. fraterculus is the most common species of Peromyscus off Santa Catalina Island in the Baja California peninsula. The records show the absence of P. slevini in the 1990s and an increasing number of P. fraterculus during the 2000s. P. slevini has recently been collected in 2007. The current situation in Santa Catalina Island shows a strong expansion of P. fraterculus and the restriction of P. slevini to the canyons. This study confirms for the first time the recent invasion of a peninsular native species in one island on the Gulf of California. Peromyscus fraterculus is a better desert adapted species in contrast to P. slevini. Under those conditions, in the near future, P. slevini could be extinct.     

Redox Proteomic Analysis Reveals Oxidative Modifications of Proteins by Increased Levels of Intracellular Reactive Oxygen Species during Hypoxia Adaptation of Aspergillus fumigatus

Aspergillus fumigatus faces abrupt changes in oxygen concentrations at the site of infection. An increasing number of studies has demonstrated that elevated production of intracellular reactive oxygen species (ROS) under low oxygen conditions plays a regulatory role in modulating cellular responses for adaptation to hypoxia. To learn more about this process in A. fumigatus, intracellular ROS production during hypoxia has been determined. The results confirm increased amounts of intracellular ROS in A. fumigatus exposed to decreased oxygen levels. Moreover, nuclear accumulation of the major oxidative stress regulator AfYap1 is observed after low oxygen cultivation. For further analysis, iodoTMT labeling of redox‐sensitive cysteine residues is applied to identify proteins that are reversibly oxidized. This analysis reveals that proteins with important roles in maintaining redox balance and protein folding, such as the thioredoxin Asp f 29 and the disulfide‐isomerase PdiA, undergo substantial thiol modification under hypoxia. The data also show that the mitochondrial respiratory complex IV assembly protein Coa6 is significantly oxidized by hypoxic ROS. Deletion of the corresponding gene results in a complete absence of hypoxic growth, indicating the importance of complex IV during adaptation of A. fumigatus to oxygen‐limiting conditions.     

Beta-globin gene cluster haplotype distribution in five Brazilian Indian tribes

Haplotypes derived from five polymorphic restriction sites in the beta-globin gene cluster were investigated in 139 individuals from five different Brazilian Indian tribes by the polymerase chain reaction (PCR). Eight haplotypes were identified. Haplotypes 2 (+????) and 6 (?++?+) were the most frequent and were common to all tribes. Their prevalences ranged from 60% to 93% and from 3% to 18%, respectively. Average heterozy-gosity measured by the Gini-Simpson index is markedly reduced among these Brazilian Indians when compared with Europeans (56%), but much less (8%) in relation to Asiatics, suggesting the absence of an important bottleneck effect in the early colonization of South America. The coefficient of gene differentiation (GST′) was estimated as 0.082 among six Brazilian Indian tribes, but when only three Tupi-Mondé-speaking tribes were considered, this estimate was reduced to 0.030. © 1995 Wiley-Liss, Inc.     

Hydrolysis of N'-benzoyl-d-arginine-p-nitroanilide by members of the Haloanaerobiaceae: additional evidence that Haloanaerobium praevalens is related to endospore-forming bacteria

Abstract Three out of the four described halophilic obligately anaerobic bacteria of the family Haloanaerobiaceae hydrolyze d -BAPA (N'-benzoyl- d -arginine-p-nitroanilide), while showing no or little l -BAPA hydrolyzing activity. This property was shown earlier to be characteristic only of non-halophilic Gram-positive endospore-forming bacteria of the genera Bacillus and Clostridium . These results suggest that Haloanaerobium praevalens , which has never been shown to produce endospores, but was shown to be related to the endosphere-forming representatives of the Haloanaerobiaceae on the basis of 16S rRNA nucleotide sequence data, shares other properties characteristics of the endospore-forming bacteria. Neither significant d -BAPA nor l -BAPA hydrolyzing activity was found in Sporohalobacter lortetii .     

Localization and Characterization of Nitric Oxide Synthase in the Rat Suprachiasmatic Nucleus: Evidence for a Nitrergic Plexus in the Biological Clock

Abstract: Behavioral and electrophysiological evidence indicates that the biological clock in the hypothalamic suprachiasmatic nuclei (SCN) can be reset at night through release of glutamate from the retinohypothalamic tract and subsequent activation of nitric oxide synthase (NOS). However, previous studies using NADPH-diaphorase staining or immunocytochemistry to localize NOS found either no or only a few positive cells in the SCN. By monitoring conversion of l -[³H]arginine to l -[³H]citrulline, this study demonstrates that extracts of SCN tissue exhibit NOS specific activity comparable to that of rat cerebellum. The enzymatic reaction requires the presence of NADPH and is Ca²⁺/calmodulin-dependent. To distinguish the neuronal isoform (nNOS; type I) from the endothelial isoform (type III), the enzyme activity was assayed over a range of pH values. The optimal pH for the reaction was 6.7, a characteristic value for nNOS. No difference in nNOS levels was seen between SCN collected in day versus night, either by western blot or by enzyme activity measurement. Confocal microscopy revealed for the first time a dense plexus of cell processes stained for nNOS. These data demonstrate that neuronal fibers within the rat SCN express abundant nNOS and that the level of the enzyme does not vary temporally. The distribution and quantity of nNOS support a prominent regulatory role for this nitrergic component in the SCN.