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Sixteen S rRNA gene sequencing is used to analyze the bacterial biodiversity in the Southern Brazilian Atlantic Forest ecosystem. The bacterial diversity is found to be influenced by factors such as altitude, [Ca.sup.2+]/[Mg.sup.2+] ratio, and [Al.sup.3+] phosphorus content while pH had no significant impact on diversity.

Byline: S.C.A. Correa, E.M. Souza, A.X. Silva, H. Yoriyaz, R.T. Lopes Thoracic radiology is of great concern because of its routine nature. It is important to avoid conditions where the amount of radiation used is more than that needed for the procedure. The purpose of this work is to use the Monte Carlo code MCNPX and the Female Adult voxel (FAX) and Male Adult voxel (MAX) phantoms to investigate how the effective doses, absorbed doses to organs and risk of cancer incidence vary for routine thoracic examinations. The risks attributable to thoracic radiological exams were estimated using the Biological Effects of Ionizing Radiations (BEIR) VII Committee Report. The results obtained suggest that different precautionary measures should be taken depending on the chosen geometric projection, and that the application of higher voltages to the X-ray tube appeared as an alternative to reduce the doses and the risk of cancer incidence.

Fragile X Mental Retardation Protein (FMRP) is a RNA-binding protein that modulates protein synthesis at the synapse and its function is regulated by glutamate. The retina is the first structure that participates in vision, and uses glutamate to transduce electromagnetic signals from light to electrochemical signals to neurons. FMRP has been previously detected in the retina, but its localization has not been studied yet. In this work, our objectives were to describe the localization of FMRP in the retina, to determine whether different exposure to dark or light stimulus alters FMRP expression in the retina, and to compare the pattern in two different species, the mouse and chick. We found that both FMRP mRNA and protein are expressed in the retina. By immunohistochemistry analysis we found that both mouse and chick present similar FMRP expression localized mainly in both plexiform layers and the inner retina. It was also observed that FMRP is down-regulated by 24 h dark adaptation compared to its expression in the retina of animals that were exposed to light for 1 h after 24 h in the dark. We conclude that FMRP is likely to participate in retinal physiology, since its expression changes with light exposure. In addition, the expression pattern and regulation by light of FMRP seems well conserved since it was similar in both mouse and chick. [ABSTRACT FROM AUTHOR]

To understand the mechanism of plant-bacterium interaction, it is critical to enumerate epiphytic bacteria colonizing the roots of the host. We developed a new approach, based on flow cytometry, for enumerating these bacteria and used it with rice plants, 7 and 20 days after colonization with Herbaspirillum rubrisubalbicans and Azospirillum brasilense. The results were compared with those obtained with the traditional plate count method. Both methods gave similar numbers of H. rubrisubalbicans associated with rice roots ( c. 109 CFU g−1). However, flow cytometry gave a number of viable cells of rice-associated A. brasilense that was approx. 10-fold greater than that obtained with the plate count method. These results suggest that the plate count method can underestimate epiphytic populations. Flow cytometry has the additional advantage that it is more precise and much faster than the plate count method. Significance and Impact of the Study Determination of precise number of root-associated bacteria is critical for plant-bacteria interaction studies. We developed a flow cytometry approach for counting bacteria and compared it with the plate count method. Our flow cytometry assay solves two major limitations of the plate count method, namely that requires long incubation times of up to 48 h and only determines culturable cells. This flow cytometry assay provides an efficient, precise and fast tool for enumerating epiphytic cells. [ABSTRACT FROM AUTHOR]

Abstract: Glutamate and GABA are, respectively, the major excitatory and inhibitory neurotransmitters in the retina, participating in the two pathways through which the retina processes light information. It has already been shown that glutamate induces GABA release from amacrine cells through a transporter-mediated mechanism, and that this process is mediated by ionotropic glutamate receptors. It is well established that glutamate can also activate metabotropic glutamate receptors, which are widely distributed in the retina, and can be detected in amacrine cell bodies and synaptic contacts. Thus, we decided to investigate the role of the activation of groups I and II metabotropic glutamate receptors in GABA release from amacrine cells in the chicken retina. Group I/II agonist trans-ACPD promoted a 40% decrease in the number of GABA-positive cells in relation to the control, effect that was prevented by antagonists of both groups. Also, the trans-ACPD effect was blocked by GAT-1 inhibitor or by antagonists of ionotropic glutamate receptors. Trans-ACPD induced release of GABA was abolished when the experiment was conducted in absence of calcium ions. Under the superfusing conditions used, trans-ACPD promoted an increase in endogenous glutamate release that was prevented when calcium was omitted from the bathing medium. The results suggest that mGluRI/II regulate the release of glutamate, likely from bipolar cells, that in turn activates GABA release from amacrine cells via a transporter mediated process. [Copyright &y& Elsevier]

Abstract: Trypanosoma cruzi is the etiological agent of Chagas disease, an important neglected illness affecting about 12–14 million people in endemic areas of Latin America. The chemotherapy of Chagas disease is quite unsatisfactory mainly due to its poor efficacy especially during the later chronic phase and the considerable well-known side effects. These facts emphasize the need to search for find new drugs. Diamidines and related compounds are minor groove binders of DNA at AT-rich sites and present excellent anti-trypanosomal activity. In the present study, six novel aromatic amidine compounds (arylimidamides and diamidines) were tested in vitro to determine activity against the infective and intracellular stages of T. cruzi, which are responsible for sustaining the infection in the mammalian hosts. In addition, their selectivity and toxicity towards primary cultures of cardiomyocyte were evaluated since these cells represent important targets of infection and inflammation in vivo. The aromatic amidines were active against T. cruzi in vitro, the arylimidamide DB1470 was the most effective compound presenting a submicromolar LD50 values, good selectivity index, and good activity at 4°C in the presence of blood constituents. Our results further justify trypanocidal screening assays with these classes of compounds both in vitro and in vivo in experimental models of T. cruzi infection. [ABSTRACT FROM AUTHOR]

Abstract: A2M is a broad spectrum proteinase inhibitor and cytokine carrier, besides presenting anti-apoptotic activity through the binding to its receptor, LRP. During Trypanosoma cruzi infection, apoptosis of host cells and intracellular parasites is commonly observed both in vivo and in vitro. Since plasma as well as tissue A2M levels are increased in both murine and human acute T. cruzi infection, we evaluated the possible role of A2M (its methylamine transformed Fast form—A2M-F) in regulating apoptotic events in peritoneal macrophages and cardiomyocytes during in vitro interaction with the parasite. Our data showed that DNA fragmentation (a hallmark of apoptosis) of both host cells and parasites was inhibited by A2M-F. Impaired apoptosis was also noted when A2M-F was added to the cultures maintained under serum deprivation. In addition, macrophages from C57/BL6 mice, known to display higher LRP levels as compared to those of C3H lineage, displayed higher reduction in the apoptotic levels during the A2M-F treatment. [Copyright &y& Elsevier]

Furamidine (DB75) and related unfused aromatic diamidines have proven useful for the treatment of parasitic infections. These compounds were primarily developed to combat infections by Pneumocystis carinii and African trypanosomes but they are also active against other parasites. Here we have investigated the in vitro effects of DB75 and its phenyl-substituted analog DB569 on two kinetoplastid haemoflagellates Trypanosomatidae: Trypanosoma cruzi and Leishmania (L) amazonensis. The phenyl-amidine compound DB569 has equivalent DNA binding properties compared to DB75 but it was selected on the basis of its distinct tumor cell distribution properties. We found that DB569 is significantly more potent than DB75 at reducing the proliferation of the parasites, using either isolated parasites in cultures or with cardiomyocyte and macrophage host cells. DB569 is effective towards the intracellular forms of T. cruzi (IC50 in the low-micromolar range) and it exhibits trypanocidal dose-dependent effects against trypomastigote forms of T. cruzi parasites obtained from the Y strain and Dm28c clone, which belong to two different biodemes. Fluorescence microscopy experiments indicated that both diamidines were mostly localized in the nucleus of the mammalian host cells and within the nuclei and kinetoplast of the parasites. Electron microscopy studies showed that the treatment of the parasites with DB75 and DB569 induces important alterations of the parasite nucleus and kinetoplast, at sites where their DNA target is localized. Altogether, the data suggest that the phenyl-substituted furamidine analogue DB569 is a potential new candidate for the treatment of the Chagas’ disease and Leishmaniasis. [Copyright &y& Elsevier]

Humoral immune response of water buffalo naturally infected with Toxocara vitulorum was monitored using three different antigens of this parasite in serum and colostrum of buffalo cows and calves. Soluble extract (Ex) and excretory/secretory (ES) larval antigens and perienteric fluid antigen (Pe) of adult T. vitulorum were used to measure the antibody levels by an indirect ELISA. Serum of 7–12 buffalo cows for the first 365 days and colostrum of the same number of buffalo cows for the first 60 days of parturition, and serum of 8–10 buffalo calves for the first 365 days after birth were assayed. The ELISA detected antibodies against all three T. vitulorum antigens in the colostrum and serum of 100% of buffalo cows and calves examined. The highest antibody levels against Ex, ES and Pe antigens were detected in the buffalo cow sera during the perinatal period and were maintained at high levels through 300 days after parturition. On the other hand, colostrum antibody concentrations of all three antigens were highest on the first day post-parturition, but decreased sharply during the first 15 days. Concomitantly to the monitoring of immune response, the parasitic status of the calves was also evaluated. In calves, antibodies passively acquired were at the highest concentrations 24 h after birth and remained at high levels until 45 days coincidentally with the peak of T. vitulorum infection. The rejection of the worms by the calves occurred simultaneously with the decline of antibody levels, which reached their lowest levels between 76 and 150 days. Thereafter, probably because of the presence of adults/larvae stimulation, the calves acquired active immunity and the antibodies started to increase slightly in the serum and plateaued between the days 211 and 365. All three antigens were detected by the serum antibodies of buffalo calves; however, the concentration of anti-Pe antibody was higher than anti-EX and anti-ES, particularly after 90 days of age. By conclusion, the buffalo cows develop immunity and keep high levels of antibodies against T. vitulorum-Ex, ES and Pe antigens and these antibodies are transferred to their calves through the colostrum. This passively acquired immunity does not protect the calves against the acquisition of the infection, but these antibodies, passively or actively acquired, may have an important role during worm rejection by the calves and prevention of intestinal reinfection. [Copyright &y& Elsevier]

Examines the role of NtrC and NifA proteins in the transcription of the nifA gene of Herbaspirillum seropedicae. Use of deletion mutagenesis; Impact of nitrogen fixation on the expression of nifA gene; Significance of the NifA protein in binding the NifA upstream activating sequence; Observation of residue hypermethylation with addition of rifampicin.

Presents information on glnB-type genes in Herbaspirillum seropedicae. Information on the glnB gene; Indepth look at the bacterial strains and plasmids; Discussion on the two glnB like genes found in Herbaspirillum seropedicae.

Abstract: γ-Aminobutyric acid (GABA) is considered to be the most important inhibitory neurotransmitter in the central nervous system, including the retina. It has been shown that nitric oxide (NO) can influence the physiology of all retinal neuronal types, by mechanisms including modulation of GABA release. However, until now, there have been no data concerning the effects on endogenous GABA release of NO produced by cells in the intact retina. In the present study, we have investigated how NO production induced by drugs influences the release of endogenous GABA in cells of the intact retina of mature chicken. Retinas were exposed to different drugs that affect NO production, and GABA remaining in the tissue was detected by immunohistochemical procedures. A specific nNOS inhibitor (7-NI) reduced the number of GABA+amacrine cells and cells in the ganglion cell layer (GCL) by 33% and 41%, respectively. A GABA transporter inhibitor blocked this effect. L-arginine (100μM), the precursor of NO, induced increases of 62% and 34% in the number of GABA+amacrine cells and GCL cells, respectively. A sodium (Na+)-free solution, 7-NI and a PKG inhibitor prevented the effect of L-arginine (100μM). However, a higher concentration of L-arginine (1mM) induced a 35% reduction in the number of GABA+cells by a Na+-dependent mechanism that was restricted to the GCL population. NMDA, which stimulates NO production, increased GABA release as indicated by 53% and 38% reductions in the number of GABA+amacrine cells and GCL cells, respectively. This effect was blocked by 7-NI only in GCL cells. We conclude that basal NO production and moderate NO production (possibly induced by L-arginine; 100μM) inhibit basal GABA release from amacrine cells and GCL cells. However, NMDA or L-arginine (1mM) induce a NO-dependent increase in GABA release in GCL cells, possibly by stimulating higher NO production. [Copyright &y& Elsevier]

Photoneutron production occurs when high energy photons, greater than 6.7MeV, interact with linear accelerator head structures. In Brazil, the National Cancer Institute, one of the centers of reference in cancer treatment, uses radiation at 4 angles (0°, 90°, 180° and 270°) as treatment protocol for prostate cancer. With the objective of minimizing the dose deposited in the patient due to photoneutrons, this study simulated radiotherapy treatment using MCNPX, considering the most realistic environment; simulating the radiotherapy room, the Linac 2300 head, the MAX phantom and the treatment protocol with the accelerator operating at 18MV. In an attempt to reduce the dose deposited by photoneutrons, an external shielding was added to the Linac 2300. Results show that the equivalent dose due to photoneutrons deposited in the patient diminished. The biggest reduction was seen in bone structures, such as the tibia and fibula, and mandible, at approximately 75%. Besides that, organs such as the brain, pancreas, small intestine, lungs and thyroid revealed a reduction of approximately 60%. It can be concluded that the shielding developed by our research group is efficient in neutron shielding, reducing the dose for the patient, and thus, the risk of secondary cancer, and increasing patient survival rates. [ABSTRACT FROM AUTHOR]