Three patterns of mitochondrial DNA nucleotide divergence in the meadow vole,Microtus pennsylvanicus

Summary The DNA sequence was determined for the cytochrome c oxidase II (COII), tRNA^Lys, and ATPase 8 genes from the mitochondrial genome of the meadow vole, Microtus pennsylvanicus. When compared to other rodents, three different patterns of evolutionary divergence were found. Nucleotide variation in tRNA^Lys is concentrated in the TC loop. Nucleotide variation in the COII gene in three genera of rodents (Microtus, Mus, Rattus) consists predominantly of transitions in the third base positions of codons. The predicted amino acid sequence in highly conserved (>92% similarity). Analysis of the ATPase 8 gene among four genera (Microtus, Cricetulus, Mus, Rattus) revealed more detectable transversions than transitions, many fixed first and second position mutations, and considerable amino acid divergence. The rate of nucleotide substitution at nonsynonymous sites in the ATPase 8 gene is 10 times the rate in the COII gene. In contrast, the estimated absolute mutation rate as determined by analysis of nucleotide substitutions at fourfold degenerate sites probably is the same for the two genes. The primary sequences of the ATPase 8 and COII peptides are constrained differently, but each peptide is conserved in terms of predicted secondary-level configuration.     

Brain and pituitary receptors for corticotropin releasing factor: Localization and differential regulation after adrenalectomy

Specific receptors for corticotropin releasing factor (CRF) were identified in two functionally distinct systems within the brain, the cortex and the limbic system. Autoradiographic mapping of the CRF receptors in the brain revealed high binding density throughout the neocortex and cerebellar cortex, subiculum, lateral septum, olfactory tract, bed nucleus of the stria terminalis, interpeduncular nucleus and superior colliculus. Moderate to low binding was found in the hippocampus, nucleus accumbens, claustrum, nucleus periventricularis thalamus, mammillary bodies, subthalamic nucleus, periaqueductal grey, locus coeruleus and nucleus of the spinal trigeminal tract. As in the anterior pituitary gland, CRF receptors in the brain were shown to be coupled to adenylate cyclase. However, in contrast to the marked decrease in CRF receptors observed after adrenalectomy in the anterior pituitary gland, CRF receptor concentration in the brain and pars intermedia of the pituitary was unchanged. The presence of CRF receptors in areas involved in the control of hypothalamic and autonomic nervous system functions is consistent with the major role of CRF in the integrated response to stress.     

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.     

Localization of sequences regulating ancestral and acquired sites of esterase6 activity in Drosophila melanogaster

We have broadly defined the DNA regions regulating esterase6 activity in several life stages and tissue types of D. melanogaster using P- element-mediated transformation of constructs that contain the esterase6 coding region and deletions or substitutions in 5' or 3' flanking DNA. Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and the primary sequences regulating its activity lie between -171 and -25 bp relative to the translation initiation site: deletion of these sequences decrease activity approximately 20-fold. Hemolymph activity is also modulated by four other DNA regions, three of which lie 5' and one of which lies 3' of the coding region. Of these, two have positive and two have negative effects, each of approximately twofold. Esterase6 activity is present also in two male reproductive tract tissues; the ejaculatory bulb, which is another ancestral activity site, and the ejaculatory duct, which is a recently acquired site within the melanogaster species subgroup. Activities in these tissues are at least in part independently regulated: activity in the ejaculatory bulb is conferred by sequences between -273 and -172 bp (threefold decrease when deleted), while activity in the ejaculatory duct is conferred by more distal sequences between -844 and -614 bp (fourfold decrease when deleted). The reproductive tract activity is further modulated by two additional DNA regions, one in 5' DNA (-613 to -284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to +2731 bp; threefold decrease when deleted) that probably overlaps the adjacent esteraseP gene. Collating these data with previous studies suggests that expression of EST6 in the ancestral sites is mainly regulated by conserved proximal sequences while more variable distal sequences regulate expression in the acquired ejaculatory duct site.      

Potentiation of the Fluoxetine-Induced Increase in Dialysate Levels of Serotonin (5-HT) in the Frontal Cortex of Freely Moving Rats by Combined Blockade of 5-HT1A and 5-HT1B Receptors with WAY 100,635 and GR 127,935

Abstract: In this study, we examined the influence of blockade of serotonin (5-HT)_1A and/or 5-HT_1B autoreceptors on the fluoxetine-induced increase in dialysate levels of 5-HT as compared with dopamine (DA) and noradrenaline (NAD) in single samples of the frontal cortex (FCx) of freely moving rats. Fluoxetine (10.0 mg/kg, s.c.) elicited a twofold increase in dialysate levels of 5-HT relative to baseline values. The selective 5-HT_1A antagonist WAY 100,635 (0.16 mg/kg, s.c.) did not influence 5-HT release alone but doubled the influence of fluoxetine on basal levels. Similarly, the selective 5-HT_1B/1D antagonist GR 127,935 (2.5 mg/kg, s.c.) did not alter basal 5-HT levels alone and doubled the fluoxetine-induced increase in 5-HT levels. Combined administration of WAY 100,635 and GR 127,935 elicited an (at least) additive rise in the fluoxetine-induced increase in 5-HT levels to eightfold basal values, without modifying resting 5-HT levels. These changes were selective for 5-HT inasmuch as the parallel (twofold) increase in DA and NAD levels provoked by fluoxetine was not potentiated. The present data demonstrate that combined blockade of 5-HT_1A and 5-HT_1B autoreceptors markedly and selectively potentiates the fluoxetine-induced increase in dialysate levels of 5-HT versus DA and NAD in the FCx of freely moving rats. These observations suggest that 5-HT_1A/1B antagonism may represent a novel strategy for the improvement in the therapeutic profile of 5-HT reuptake inhibitor antidepressant agents and that 5-HT may be primarily involved in such interactions.     

Monoclonal antibodies block the bromelain-mediated release of human placental alkaline phosphatase from cultured cancer cells

Certain monoclonal antibodies (mAbs) to human placental alkaline phosphatase (PLAP) block bromelain cleavage of a 2-kDa segment from each of the two polypeptide chains of PLAP. These mAbs also prevent the release of PLAP from cultured cancer cell surfaces by bromelain. Such proteolysis-blocking mAbs serve as tools to specifically modify the molecular topography of cell surfaces by protease treatment.     

Biocides formulation of essential oils having antimicrobial activity

Essential oils of fennel, peppermint, caraway, eucalyptus, geranium and lemon were tested for their antimicrobial activities against some plant pathogenic micro-organisms (Fusarium oxysporum, Alternaria alternate, Penicilium italicum Penicilium digitatum and Botyritus cinerea). Essential oils of fennel, peppermint, caraway were selected as an active ingredient for the formulation of biocides due to their efficiency in controlling the tested micro-organisms. Successful emulsifiable concentrates (biocides) were prepared from these oils using different emulsifiers (Emulgator B.L.M. Tween20 and Tween80) and different fixed oils (sesame, olive, cotton and soybean oils). Physico-chemical properties of the formulated biocide (spontaneous emulsification, emulsion stability test, cold stability and heat stability tests as well as viscosity, surface tension and pH) were measured. The prepared biocides were ready to be tested for application in a future work as a safe pesticide against different pathogens.