Balance between the two kinin receptors in the progression of experimental focal and segmental glomerulosclerosis in mice

Focal and segmental glomerulosclerosis (FSGS) is one of the most important renal diseases related to end-stage renal failure. Bradykinin has been implicated in the pathogenesis of renal inflammation, whereas the role of its receptor 2 (B2RBK; also known as BDKRB2) in FSGS has not been studied. FSGS was induced in wild-type and B2RBK-knockout mice by a single intravenous injection of Adriamycin (ADM). In order to further modulate the kinin receptors, the animals were also treated with the B2RBK antagonist HOE-140 and the B1RBK antagonist DALBK. Here, we show that the blockage of B2RBK with HOE-140 protects mice from the development of FSGS, including podocyte foot process effacement and the re-establishment of slit-diaphragm-related proteins. However, B2RBK-knockout mice were not protected from FSGS. These opposite results were due to B1RBK expression. B1RBK was upregulated after the injection of ADM and this upregulation was exacerbated in B2RBK-knockout animals. Furthermore, treatment with HOE-140 downregulated the B1RBK receptor. The blockage of B1RBK in B2RBK-knockout animals promoted FSGS regression, with a less-inflammatory phenotype. These results indicate a deleterious role of both kinin receptors in an FSGS model and suggest a possible cross-talk between them in the progression of disease.KEY WORDS: Focal and segmental glomerulosclerosis, Bradykinin receptors, Inflammation, Podocyte, Fibrosis     

A strain of <Emphasis Type="Italic">Meyerozyma guilliermondii</Emphasis> isolated from sugarcane juice is able to grow and ferment pentoses in synthetic and bagasse hydrolysate media

The search for new microbial strains that are able to withstand inhibitors released from hemicellulosic hydrolysis and are also still able to convert sugars in ethanol/xylitol is highly desirable. A yeast strain isolated from sugarcane juice and identified as Meyerozyma guilliermondii was evaluated for the ability to grow and ferment pentoses in synthetic media and in sugarcane bagasse hydrolysate. The yeast grew in xylose, arabinose and glucose at the same rate at an initial medium pH of 5.5. At pH 4.5, the yeast grew more slowly in arabinose. There was no sugar exhaustion within 60 h. At higher xylose concentrations with a higher initial cell concentration, sugar was exhausted within 96 h at pH 4.5. An increase of 350 % in biomass was obtained in detoxified hydrolysates, whereas supplementation with 3 g/L yeast extract increased biomass production by approximately 40 %. Ethanol and xylitol were produced more significantly in supplemented hydrolysates regardless of detoxification. Xylose consumption was enhanced in supplemented hydrolysates and arabinose was consumed only when xylose and glucose were no longer available. Supplementation had a greater impact on ethanol yield and productivity than detoxification; however, the product yields obtained in the present study are still much lower when compared to other yeast species in bagasse hydrolysate. By the other hand, the fermentation of both xylose and arabinose and capability of withstanding inhibitors are important characteristics of the strain assayed.     

The sample processing time interval as an influential factor in flow cytometry analysis of lymphocyte subsets

The objective of this paper is to propose a protocol to analyze blood samples in yellow fever 17DD vaccinated which developed serious adverse events. We investigated whether or not the time between sample collection and sample processing could interfere in lymphocyte subset percentage, for it is often impossible to analyze blood samples immediately after collection due to transport delay from collection places to the flow cytometry facility. CD4+CD38+ T, CD8+CD38+ T, CD3+ T, CD19+ B lymphocyte subsets were analyzed by flow cytometry in nine healthy volunteers immediately after blood collection and after intervals of 24 and 48 h. The whole blood lysis method and gradient sedimentation by Histopaque were applied to isolate peripheral blood mononuclear cells for flow cytometry analyses. With the lysis method, there was no significant change in lymphocyte subset percentage between the two time intervals (24 and 48 h). In contrast, when blood samples were processed by Histopaque gradient sedimentation, time intervals for sample processing influenced the percentage in T lymphocyte subsets but not in B cells. From the results obtained, we could conclude that the whole blood lysis method is more appropriate than gradient sedimentation by Histopaque for immunophenotyping of blood samples collected after serious adverse events, due to less variation in the lymphocyte subset levels with respect to the time factor.     

Function inferences from a molecular structural model of bacterial ParE toxin

Toxin-antitoxin (TA) systems contribute to plasmid stability by a mechanism that relies on the differential stabilities of the toxin and antitoxin proteins and leads to the killing of daughter bacteria that did not receive a plasmid copy at the cell division. ParE is the toxic component of a TA system that constitutes along with RelE an important class of bacterial toxin called RelE/ParE superfamily. For ParE toxin, no crystallographic structure is available so far and rare in vitro studies demonstrated that the target of toxin activity is E. coli DNA gyrase. Here, a 3D Model for E. coli ParE toxin by molecular homology modeling was built using MODELLER, a program for comparative modeling. The Model was energy minimized by CHARMM and validated using PROCHECK and VERIFY3D programs. Resulting Ramachandran plot analysis it was found that the portion residues failing into the most favored and allowed regions was 96.8%. Structural similarity search employing DALI server showed as the best matches RelE and YoeB families. The Model also showed similarities with other microbial ribonucleases but in a small score. A possible homologous deep cleft active site was identified in the Model using CASTp program. Additional studies to investigate the nuclease activity in members of ParE family as well as to confirm the inhibitory replication activity are needed. The predicted Model allows initial inferences about the unexplored 3D structure of the ParE toxin and may be further used in rational design of molecules for structure-function studies.     

Local knowledge,use, and conservation of wild birds in the semi-arid region of Paraíba state,northeastern Brazil

Background

The use of wild birds, for several purposes, is directly associated with cultural, ecological, and conservation issues. This study aimed to inventory the wild birds known and used in three communities in Paraíba state, northeast Brazil, and to investigate the sociocultural context in which these activities occur.

Methods

A total of 179 people (98 women and 81 men) were interviewed. Data were collected through free interviews, using semi-structured forms, and posing questions about the use of local wild birds. The species were identified by direct observation of the birds, analysis of photographic records, and the use of a scientific guide.

Results

Each species’ use value (UV) was calculated in three different ways: UV_general, UV_current, and UV_potential. These UVs ranged from 0.01 to 1.15 for UV_g, 0 to 0.21 for UV_c, and 0.01 to 1.02 for UV_p. A total of 99 species, 81 genera, and 40 families were recorded and classified into the use categories of food, breeding, and medicinal. Thraupidae (12 species), Columbidae, Accipitridae, and Icteridae (8 species each) were the most diverse families.

Conclusions

The use of wild birds is a widespread activity in the studied areas, where many species are used. This demonstrates the need to conduct studies to assess the pressure suffered by these bird species, as well as the need to create public policies that intervene in the use and conservation of wild birds.

     

Discovery of a novel series of pyridine and pyrimidine carboxamides as potent and selective covalent inhibitors of Btk

Btk is an attractive target for the treatment of a range of Bcell malignancies as well as several autoimmune diseases such as murine lupus and rheumatoid arthritis. Several covalent irreversible inhibitors of Btk are currently in development including ibrutinib which was approved for treatment of B-cell malignancies. Herein, we describe our efforts using X-ray guided structure based design (SBD) to identify a novel chemical series of covalent Btk inhibitors. The resulting pyridine carboxamides were potent and selective inhibitors of Btk having excellent enzymatic and cellular inhibitory activity.     

Soil charcoal as long‐term pyrogenic carbon storage in Amazonian seasonal forests

Forest fires (paleo + modern) have caused charcoal particles to accumulate in the soil vertical profile in Amazonia. This forest compartment is a long‐term carbon reservoir with an important role in global carbon balance. Estimates of stocks remain uncertain in forests that have not been altered by deforestation but that have been impacted by understory fires and selective logging. We estimated the stock of pyrogenic carbon derived from charcoal accumulated in the soil profile of seasonal forest fragments impacted by fire and selective logging in the northern portion of Brazilian Amazonia. Sixty‐nine soil cores to 1‐m depth were collected in 12 forest fragments of different sizes. Charcoal stocks averaged 3.45 ± 2.17 Mg ha^?1 (2.24 ± 1.41 Mg C ha^?1). Pyrogenic carbon was not directly related to the size of the forest fragments. This carbon is equivalent to 1.40% (0.25% to 4.04%) of the carbon stocked in aboveground live tree biomass in these fragments. The vertical distribution of pyrogenic carbon indicates an exponential model, where the 0–30 cm depth range has 60% of the total stored. The total area of Brazil's Amazonian seasonal forests and ecotones not altered by deforestation implies 65–286 Tg of pyrogenic carbon accumulated along the soil vertical profile. This is 1.2–2.3 times the total amount of residual pyrogenic carbon formed by biomass burning worldwide in 1 year. Our analysis suggests that the accumulated charcoal in the soil vertical profile in Amazonian forests is a substantial pyrogenic carbon pool that needs to be considered in global carbon models.     

ADENOSINE TRIPHOSPHATASE ACTIVITY IN THE MEMBRANES OF THE SQUID NERVE FIBER

This investigation deals with the localization of sites of ATPase activity, especially of transport ATPase, in nerve fibers of the squid Doryteuthis plei, at the subcellular level. Splitting of ATP liberates inorganic phosphate which reacts with lead to form a precipitate in the tissue. The reaction was made on nerve fibers fixed with glutaraldehyde. Frozen slices were incubated in Wachstein-Meisel medium containing ATP and Pb(NO₃)₂. Deposits of reaction product were found in the axolemma (towards its axoplasmic side), Schwann cell membranes (mainly at the channels crossing the layer), and mitochondria. Control experiments revealed that no deposits were observed in nerve fibers fixed in osmium tetroxide prior to incubation in the medium containing ATP, or in nerve fibers incubated without substrate or with adenosine monophosphate, adenosine diphosphate, glycerophosphate, or guanosine triphosphate as substrate. For evaluation of transport ATPase activity, these findings were compared with results obtained with nerve fibers treated with G-strophanthin or K-strophanthoside before or after glutaraldehyde fixation. The cardiac glycosides produced a disappearance or diminution of the deposits. The largest inhibitory effect was observed in the axolemma. The findings indicate that the highest ATPase activity is localized in the axolemma and may be due primarily to transport ATPase.     

Partial purification and characterization of the (Ca2+ + Mg2+)-ATPase from squid optic nerve plasma membrane

A membrane fraction enriched in axolemma was obtained from optic nerves of the squid (Sepiotheutis sepioidea) by differential centrifugation and density gradient fractionation. The preparation showed an oligomycin- and NaN₃-insensitive (Ca²⁺ + Mg²⁺)-ATPase activity. The dependence of the ATPase activity on calcium concentration revealed the presence of two saturable components. One had a high affinity for calcium ($\text{K}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}^1\text{= 0.12 μ}\text{M}$) and the second had a comparatively low affinity ($\text{K}{}^2{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 49.5 μ}\text{M}$). Only the high-affinity component was specifically inhibited by vanadate (K₁ = 35 μM). Calmodulin (12.5 μ/ml) stimulated the (Ca²⁺ + Mg²⁺)-ATPase by approx. 50%, and this stimulation was abolished by trifluoperazine (10 μM). Further treatment of the membrane fraction with 1% Nonidet P-40 resulted in a partial purification of the ATPase about 15-fold compared to the initial homogenate. This (Ca²⁺ + Mg²⁺)-ATPase from squid optic nerve displays some properties similar to those of the uncoupled Ca²⁺-pump described in internally dialyzed squid axons, suggesting that it could be its enzymatic basis.     

A new internal perfusion method for transport studies in squid giant axons

A new internal perfusion method has been developed which allows control of the internal solute composition in squid axons. The superiority of this technique compared to the old perfusion methods is shown by the experiments performed which have reproduced, both qualitatively and quantitatively, the Na⁺ and Ca²⁺ fluxes observed in intact and dialyzed axons. Compared with the internal dialysis, the perfusion method has the advantage that the permeability barrier given by the porous capillary has been eliminated. This allows the introduction into the axon of solutes with very high molecular weight, at the same time that a fast and reliable internal control can be achieved.