A sustentabilidade e a gestão hídrica de sistemas agroflorestais em comunidades rurais familiares, no nordeste do Pará.

A dinâmica produtiva nos agroecossistemas familiares amazônicos, aliada a uma diversidade sócio produtiva, propicia modificações interessantes nesse território, além de potencializar impactos socioeconômicos e ambientais positivos. A inserção de inovações técnicas, especialmente no tocante a implantação de Sistemas Agroflorestais, surge como uma alternativa viável de consolidação de espaços produtivos capazes de manter a diversidade ecológica e favorecer ganhos socioeconômicos locais. Buscou-se avaliar, através de indicadores de sustentabilidade as formas de manejo do uso da água em processos produtivos, realizados em agroecossistemas familiares nos municípios de Igarapé-Açu e Marapanim, localizados no estado do Pará. Para tanto, a utilização de ferramentas que auxiliam na escolha de combinações e modos de produção é imprescindível para a interpretação do cenário atual. Dessa forma, o processo metodológico desenha-se a partir da utilização da ferramenta Ambitec-Agro a fim de avaliar o uso da água em agroecossistemas tidos como agroecológicos. Assim, obtém-se a interpretação necessária acerca do impacto gerado pelo incremento produtivo em cada unidade familiar, considerando o uso de insumo e recursos, qualidade ambiental, respeito ao consumidor, gestão e administração, renda, emprego, e saúde ambiental. Os principais resultados apontaram que a todas as Unidades Produtivas têm índice de impacto econômicos e sociais positivos, quanto aos índices ambientais, três foram classificadas como negativas. No entanto, conforme a metodologia, todas as Unidades Produtivas investigadas apresentaram-se sustentáveis. Quanto à demanda racional, 60% das Unidades Produtivas foram classificadas como parcialmente racionais, já em relação à qualidade de agua, 70% das Unidades Produtivas enquadraram-se como adequada para o uso. Por fim, constatou-se que este sistema foi capaz de avaliar as Unidades Produtivas, revelando as formas de manejo considerando a qualidade e quantidade do uso da água na atividade agrícola. Embora algumas unidades produtivas alcançaram indicadores relativamente baixo em relação a sustentabilidade global, a implantação de Sistemas Agroflorestais nos agroecossistemas estudados se mostrou promissora na manutenção dos recursos hídricos e ampliação da diversidade ecológica e produtiva

Spatial and temporal dynamics at an actively silicifying hydrothermal system

Steep Cone Geyser is a unique geothermal feature in Yellowstone National Park (YNP), Wyoming, actively gushing silicon-rich fluids along outflow channels possessing living and actively silicifying microbial biomats. To assess the geomicrobial dynamics occurring temporally and spatially at Steep Cone, samples were collected at discrete locations along one of Steep Cone’s outflow channels for both microbial community composition and aqueous geochemistry analysis during field campaigns in 2010, 2018, 2019, and 2020. Geochemical analysis characterized Steep Cone as an oligotrophic, surface boiling, silicious, alkaline-chloride thermal feature with consistent dissolved inorganic carbon and total sulfur concentrations down the outflow channel ranging from 4.59 ± 0.11 to 4.26 ± 0.07 mM and 189.7 ± 7.2 to 204.7 ± 3.55 μM, respectively. Furthermore, geochemistry remained relatively stable temporally with consistently detectable analytes displaying a relative standard deviation <32%. A thermal gradient decrease of ~55°C was observed from the sampled hydrothermal source to the end of the sampled outflow transect (90.34°C ± 3.38 to 35.06°C ± 7.24). The thermal gradient led to temperature-driven divergence and stratification of the microbial community along the outflow channel. The hyperthermophile Thermocrinis dominates the hydrothermal source biofilm community, and the thermophiles Meiothermus and Leptococcus dominate along the outflow before finally giving way to more diverse and even microbial communities at the end of the transect. Beyond the hydrothermal source, phototrophic taxa such as Leptococcus, Chloroflexus, and Chloracidobacterium act as primary producers for the system, supporting heterotrophic growth of taxa such as Raineya, Tepidimonas, and Meiothermus. Community dynamics illustrate large changes yearly driven by abundance shifts of the dominant taxa in the system. Results indicate Steep Cone possesses dynamic outflow microbial communities despite stable geochemistry. These findings improve our understanding of thermal geomicrobiological dynamics and inform how we can interpret the silicified rock record

AXY3 encodes a α-xylosidase that impacts the structure and accessibility of the hemicellulose xyloglucan in Arabidopsis plant cell walls

Xyloglucan is the most abundant hemicellulose in the walls of dicots such as Arabidopsis. It is part of the load-bearing structure of a plant cell and its metabolism is thought to play a major role in cell elongation. However, the molecular mechanism by which xyloglucan carries out this and other functions in planta is not well understood. We performed a forward genetic screen utilizing xyloglucan oligosaccharide mass profiling on chemically mutagenized Arabidopsis seedlings to identify mutants with altered xyloglucan structures termed axy-mutants. One of the identified mutants, axy3.1, contains xyloglucan with a higher proportion of non-fucosylated xyloglucan subunits. Mapping revealed that axy3.1 contains a point mutation in XYLOSIDASE1 (XYL1) known to encode for an apoplastic glycoside hydrolase releasing xylosyl residues from xyloglucan oligosaccharides at the non-reducing end. The data support the hypothesis that AXY3/XYL1 is an essential component of the apoplastic xyloglucan degradation machinery and as a result of the lack of function in the various axy3-alleles leads not only to an altered xyloglucan structure but also a xyloglucan that is less tightly associated with other wall components. However, the plant can cope with the excess xyloglucan relatively well as the mutant does not display any visible growth or morphological phenotypes with the notable exception of shorter siliques and reduced fitness. Taken together, these results demonstrate that plant apoplastic hydrolases have a larger impact on wall polymer structure and function than previously thought

The use of dual-lumen balloon for embolization of peripheral arteriovenous malformations

PURPOSEWe aimed to evaluate the safety and feasibility of the embolization of peripheral arteriovenous malformation (AVM) with non-adhesive liquid agents (NALA) injected by dual-lumen balloons (DLB).METHODSWe conducted a multicenter retrospective study between January 2017 and June 2019, including patients with peripheral AVM embolized with NALA by DLB. Fourteen patients were included. The AVM classification, technical and clinical success were evaluated, as were nidus size, liquid agent used, volume and time of injection in DLB, complications, follow-up and need of surgical intervention.RESULTSThe mean age of the patients was 37±22.5 years (range, 6–82 years). The mean nidus size was 5.2±2.4 cm (range, 3.0–12.0 cm). By Schobinger classification, 11 AVMs were classified in stage 3 and 3 AVMs were classified in stage 2. By Cho’s classification, 2 AVMs were in stage II, 4 AVMs were in stage I, 4 AVMs were in stage IIIa and 4 AVMs were in stage IIIb. Onyx was used in 11 patients (78.6%), while Squid, PHIL, and both Onyx and Squid were used in one patient each (7.1%). Seven patients (50%) required one session of embolization, 4 patients (28.6%) required two, 2 patients (14.3%) required three and 1 patient (7.1%) required four sessions. Complete nidus exclusion was achieved in 11 patients (78.6%), optimal clinical response in 12 patients (85.7%). Four patients (28.6%) exhibited minor complications, all controlled. No major complications were seen. Four patients underwent surgical intervention (28.6%). CONCLUSIONThe embolization of peripheral AVM with NALA in DLB appears to be safe and feasible, achieving high rates of technical and clinical success

Inducible expression of Pisum sativum xyloglucan fucosyltransferase in the pea root cap meristem, and effects of antisense mRNA expression on root cap cell wall structural integrity

Mitosis and cell wall synthesis in the legume root cap meristem can be induced and synchronized by the nondestructive removal of border cells from the cap periphery. Newly synthesized cells can be examined microscopically as they differentiate progressively during cap development, and ultimately detach as a new population of border cells. This system was used to demonstrate that Pisum sativum L. fucosyl transferase (PsFut1) mRNA expression is strongly expressed in root meristematic tissues, and is induced >2-fold during a 5-h period when mitosis in the root cap meristem is increased. Expression of PsFut1 antisense mRNA in pea hairy roots under the control of the CaMV35S promoter, which exhibits meristem localized expression in pea root caps, resulted in a 50–60% reduction in meristem localized endogenous PsFut1 mRNA expression measured using whole mount in situ hybridization. Changes in gross levels of cell wall fucosylated xyloglucan were not detected, but altered surface localization patterns were detected using whole mount immunolocalization with CCRC-M1, an antibody that recognizes fucosylated xyloglucan. Emerging hairy roots expressing antisense PsFut1 mRNA appeared normal macroscopically but scanning electron microscopy of tissues with altered CCRC-M1 localization patterns revealed wrinkled, collapsed cell surfaces. As individual border cells separated from the cap periphery, cell death occurred in correlation with extrusion of cellular contents through breaks in the wall