Impairment of Nitric Oxide Pathway by Intravascular Hemolysis Plays a Major Role in Mice Esophageal Hypercontractility: Reversion by Soluble Guanylyl Cyclase Stimulator.

Paroxysmal nocturnal hemoglobinuria (PNH) patients display exaggerated intravascular hemolysis and esophageal disorders. Since excess hemoglobin in the plasma causes reduced nitric oxide (NO) bioavailability and oxidative stress, we hypothesized that esophageal contraction may be impaired by intravascular hemolysis. This study aimed to analyze the alterations of the esophagus contractile mechanisms in a murine model of exaggerated intravascular hemolysis induced by phenylhydrazine (PHZ). For comparative purposes, sickle cell disease (SCD) mice were also studied, a less severe intravascular hemolysis model. Esophagus rings were dissected free and placed in organ baths. Plasma hemoglobin was higher in PHZ compared with SCD mice, as expected. The contractile responses produced by carbachol (CCh), KCl, and electrical-field stimulation (EFS) were superior in PHZ esophagi compared with control but remained unchanged in SCD mice. Preincubation with the NO-independent soluble guanylate cyclase stimulator 3-(4-amino-5-cyclopropylpyrimidin-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine (BAY 41-2272; 1 µM) completely reversed the increased contractile responses to CCh, KCl, and EFS in PHZ mice, but responses remained unchanged with prior treatment with NO donor sodium nitroprusside (300 µM). Protein expression of 3-nitrotyrosine and 4-hydroxynonenal increased in esophagi from PHZ mice, suggesting a state of oxidative stress. In endothelial nitric oxide synthase gene-deficient mice, the contractile responses elicited by KCl and CCh were increased in the esophagus but remained unchanged with the intravascular hemolysis induced by PHZ. In conclusion, our results show that esophagus hypercontractile state occurs in association with lower NO bioavailability due to exaggerated hemolysis intravascular and oxidative stress. Moreover, our study supports the hypothesis that esophageal disorders in PNH patients are secondary to intravascular hemolysis affecting the NO-cGMP pathway.

Functional groups of entomofauna associated to aquatic macrophytes in Correntoso river, Rio Negro sub-region, Pantanal, Mato Grosso do Sul State, Brazil - doi: 10.4025/actascibiolsci.v34i1.7822

This work aimed to study the structure of functional groups of entomofauna associated to aquatic macrophytes in Correntoso river, Rio Negro sub-region, Pantanal, Mato Grosso do Sul State, Brazil. Six samples were taken in different seasonal periods; ebb, dry and wet. The organisms were collected using D net (300 m mesh), sweeping five times through the roots of macrophyte banks at each sample session. Three environments were compared (open, intermediary, close) using data from six collection sites, through which were analyzed absolute abundance, observed richness of families and the sampled specimens were also separated in functional groups. A total of 60 families from 12 orders of Insecta were registered, totaling 19,773 sampled insects. The largest number of families was categorized into predators functional group, with 34 families collected, followed by the collectors with 17, shredders-herbivores ten and scrapers eight.

Distribution of entomofauna associated with aquatic macrophytes in the reflux of the Correntoso river, Pantanal do Negro, Mato Grosso do Sul State, Brazil - DOI: 10.4025/actascibiolsci.v31i2.1182 / Distribuição da entomofauna associada às macrófitas aquáticas na vazante do rio Correntoso, Pantanal do Negro, Estado do Mato Grosso do Sul, Brasil - DOI: 10.4025/actascibiolsci.v31i2.1182

This work aimed ato research the distribution of insects associated with aquatic macrophytes and the similarity among collection sites during the reflux period in a stretch of Correntoso river, Pantanal do Negro, Mato Grosso do Sul State, Brazil. The collection sites were determined by changes in the riparian formation structure, characterized as open when there is communication with flooded fields and intermediary and closed when there is not any communication with flooded fields. Three collections were taken at six sample sites, during reflux periods. The organisms were collected using a D net, 300 µm mesh, with samples from five nets thrown in roots of aquatic macrophytes. Family richness, absolute and relative abundance of the insects found, and similarity of collection sites were analyzed using Euclidian distance and complete connection, Shannon-Wiener diversity index, with log2. Sixty-four families from 10 orders of Hexapoda class were registered, totaling 2,525 individuals 2,405 of them aquatic and semi- aquatic, and 120 terrestrial. The collect sites did not present a fixed model of similarity, and the formation of groups occurred in distinct forms at each collection.

Este trabalho teve como objetivo pesquisar a distribuição de insetos associados a macrófitas aquáticas e a similaridade dos sítios de coleta, no período de vazante, em um trecho do rio Correntoso, Pantanal do Negro, Estado do Mato Grosso do Sul, Brasil. Os sítios de coleta foram determinados conforme a mudança na estrutura da formação ripária, caracterizados como abertos com comunicação com campos inundáveis; intermediários sem comunicação com campos inundáveis; fechados sem comunicação com campos inundáveis. Foram realizadas três coletas durante o período de vazante, em seis sítios de coletas. Os organismos foram coletados utilizando rede D com malha de 300 µm e esforço amostral de cinco lances de rede em raízes de macrófitas aquáticas. Foi analisada a riqueza de famílias, a abundância absoluta e relativa dos insetos encontrados, a similaridade dos sítios de coleta por análise de agrupamento, utilizando distância euclidiana e ligação completa, índice de diversidade de Shannon-Wienner, com log2. Foram registradas 64 famílias de dez ordens da Classe Hexapoda, totalizando 2.525 indivíduos, 2.405 aquáticos e semi-aquáticos e 120 terrestres. Os sítios de coleta não apresentaram padrão fixo de similaridade, e a formação dos grupos ocorreu de forma distinta a cada coleta.