Consortium diversity of a sulfate‐reducing biofilm developed at acidic pH influent conditions in a down‐flow fluidized bed reactor

Sulfate reduction is an appropriate approach for the treatment of effluents with sulfate and dissolved metals. In sulfate‐reducing reactors, acetate may largely contribute to the residual organic matter, because not all sulfate reducers are able to couple the oxidation of acetate to the reduction of sulfate, limiting the treatment efficiency. In this study, we investigated the diversity of a bacterial community in the biofilm of a laboratory scale down‐flow fluidized bed reactor, which was developed under sulfidogenic conditions at an influent pH between 4 and 6. The sequence analysis of the microbial community showed that the 16S rRNA gene sequence of almost 50% of the clones had a high similarity with Anaerolineaceae. At second place, 33% of the 16S rRNA phylotypes were affiliated with the sulfate‐reducing bacteria Desulfobacca acetoxidans and Desulfatirhabdium butyrativorans, suggesting that acetotrophic sulfate reduction was occurring in the system. The remaining bacterial phylotypes were related to fermenting bacteria found at the advanced stage of reactor operation. The results indicate that the acetotrophic sulfate‐reducing bacteria were able to remain within the biofilm, which is a significant result because few natural consortia harbor complete oxidizing sulfate‐reducers, improving the acetate removal via sulfate reduction in the reactor.     

Lkb1 Loss Promotes Tumor Progression of BRAFV600E-Induced Lung Adenomas

Aberrant activation of MAP kinase signaling pathway and loss of tumor suppressor LKB1 have been implicated in lung cancer development and progression. Although oncogenic KRAS mutations are frequent, BRAF mutations (BRAF^V600E) are found in 3% of human non-small cell lung cancers. Contrary to KRAS mutant tumors, BRAF^V600E-induced tumors are benign adenomas that fail to progess. Interestingly, loss of tumor supressor LKB1 coexists with KRAS oncogenic mutations and synergizes in tumor formation and progression, however, its cooperation with BRAF^V600E oncogene is unknown. Our results describe a lung cell population in neonates mice where expression of BRAF^V600E leads to lung adenoma development. Importantly, expression of BRAF^V600E concomitant with the loss of only a single-copy of Lkb1, overcomes senencence–like features of BRAF^V600E-mutant adenomas leading malignization to carcinomas. These results posit LKB1 haploinsufficiency as a risk factor for tumor progression of BRAF^V600E mutated lung adenomas in human cancer patients.     

The res (restored cell structure by salinity) tomato mutant reveals the role of the DEAD-box RNA helicase SlDEAD39 in plant development and salt response

Increasing evidences highlight the importance of DEAD-box RNA helicases in plant development and stress responses. In a previous study, we characterized the tomato res mutant (restored cell structure by salinity), showing chlorosis and development alterations that reverted under salt-stress conditions. Map-based cloning demonstrates that RES gene encodes SlDEAD39, a chloroplast-targeted DEAD-box RNA helicase. Constitutive expression of SlDEAD39 complements the res mutation, while the silencing lines had a similar phenotype than res mutant, which is also reverted under salinity. Functional analysis of res mutant proved SlDEAD39 is involved in the in vivo processing of the chloroplast, 23S rRNA, at the hidden break-B site, a feature also supported by in vitro binding experiments of the protein. In addition, our results show that other genes coding for chloroplast-targeted DEAD-box proteins are induced by salt-stress, which might explain the rescue of the res mutant phenotype. Interestingly, salinity restored the phenotype of res adult plants by increasing their sugar content and fruit yield. Together, these results propose an unprecedented role of a DEAD-box RNA helicase in regulating plant development and stress response through the proper ribosome and chloroplast functioning, which, in turn, represents a potential target to improve salt tolerance in tomato crops.     

Corrosion of aluminum alloy 2024 by microorganisms isolated from aircraft fuel tanks

Abstract

Microorganisms frequently contaminate jet fuel and cause corrosion of fuel tank metals. In the past, jet fuel contaminants included a diverse group of bacteria and fungi. The most common contaminant was the fungus Hormoconis resinae. However, the jet fuel community has been altered by changes in the composition of the fuel and is now dominated by bacterial contaminants. The purpose of this research was to determine the composition of the microbial community found in fuel tanks containing jet propellant-8 (JP-8) and to determine the potential of this community to cause corrosion of aluminum alloy 2024 (AA2024). Isolates cultured from fuel tanks containing JP-8 were closely related to the genus Bacillus and the fungi Aureobasidium and Penicillium. Biocidal activity of the fuel system icing inhibitor diethylene glycol monomethyl ether is the most likely cause of the prevalence of endospore forming bacteria. Electrochemical impedance spectroscopy and metallographic analysis of AA2024 exposed to the fuel tank environment indicated that the isolates caused corrosion of AA2024. Despite the limited taxonomic diversity of microorganisms recovered from jet fuel, the community has the potential to corrode fuel tanks.     

Asymmetric Allylation of α‐Ketoester‐Derived N‐Benzoylhydrazones Promoted by Chiral Sulfoxides/N‐Oxides Lewis Bases: Highly Enantioselective Synthesis of Quaternary α‐Substituted α‐Allyl‐α‐Amino Acids

Chiral sulfoxides/N‐oxides (R)‐ 1 and (R,R)‐ 2 are effective chiral promoters in the enantioselective allylation of α‐keto ester N‐benzoylhydrazone derivatives 3a , 3b , 3c , 3d , 3e , 3f , 3g to generate the corresponding N‐benzoylhydrazine derivatives 4a , 4b , 4c , 4d , 4e , 4f , 4g , with enantiomeric excesses as high as 98%. Representative hydrazine derivatives 4a , 4b were subsequently treated with SmI₂, and the resulting amino esters 5a , 5b with LiOH to obtain quaternary α‐substituted α‐allyl α‐amino acids 6a , 6b , whose absolute configuration was assigned as (S), with fundament on chemical correlation and electronic circular dichroism (ECD) data. Chirality 25:529–540, 2013. © 2013 Wiley Periodicals, Inc.     

Influence of Toxoplasma gondii Acute Infection on Cholinesterase Activities of Wistar Rats

Several studies have shown the mechanisms and importance of immune responses against Toxoplasma gondii infection and the notable role of cholinesterases in inflammatory reactions. However, the association between those factors has not yet been investigated. Therefore, the aim of this study was to evaluate the acetylcholinesterase (AChE) activity in blood and lymphocytes and the activity of butyrylcholinesterase (BChE) in serum of rats experimentally infected with T. gondii during the acute phase of infection. For that, an in vivo study was performed with evaluations of AChE and BChE activities on days 5 and 10 post-infection (PI). The activity of AChE in blood was increased on day 5 PI, while in lymphocytes its activity was enhanced on days 5 and 10 PI (P<0.05). No significant difference was observed between groups regarding to the activity of BChE in serum. A positive (P<0.01) correlation was observed between AChE activity and number of lymphocytes. The role of AChE as an inflammatory marker is well known in different pathologies; thus, our results lead to the hypothesis that AChE has an important role in modulation of early immune responses against T. gondii infection.     

Comparative bionomics of four populations of Meccus longipennis (Hemiptera: Reduviidae: Triatominae) under laboratory conditions

The values of biological parameters related to the life cycles of four populations of Meccus longipennis (Reduviidae: Triatominae) were evaluated. Cohorts of each of the four studied populations from different geographical areas of Mexico were maintained under similar laboratory conditions and then compared. The population from El Saucito de Araujo was different from the other three studied populations, which could help explain the secondary importance of M. longipennis in the state of Chihuahua. This paper also supports the proposition that biological traits are important criteria for determining relationships between populations.     

Pollen morphology and systematics of Atripliceae (Chenopodiaceae)

Pollen morphology of 58 species from 17 putative genera of the tribe Atripliceae (Chenopodiaceae) was investigated using light (LM) and scanning electron microscopy (SEM). Morphological variation was analyzed based on a dense sampling of the subtribes Atriplicinae and Eurotiinae, including many of the species in the two largest genera: Atriplex and Obione. The pantoporate pollen grains of Atripliceae are characterized by their spheroidal or subspheroidal shape, flat or moderately vaulted mesoporia with 21–120 pores, tectum with 1–8 spinules and 5–28(?38) puncta per?µm², and 1–13 ectexinous bodies bearing 1–7 spinules each. Taxonomic relevance of the most important pollen morphological characters is discussed (pollen diameter, pore number, pore diameter, interporal distance, spinule and puncta density and ratio, number of ectexinous bodies, and their spinules). Pollen morphological data support the exclusion of Suckleya from the tribe and the recognition of subtribe Eurotiinae, but suggest that it needs to be reviewed. Pollen does not support generic recognition of Atriplex, Neopreissia and Obione and infrageneric subdivisions as currently recognized, and suggests the need to review them. Smaller or monotypic genera, such as Axyris, Ceratocarpus, Endolepis, Krascheninnikovia, Microgynoecium, Proatriplex and Spinacia have distinctive pollen morphological characters that support their generic status. Grayia needs to be reevaluated; although its two species are distinct from all the other species in the study, there are notable differences between each of them, and this suggests they may not form a natural group. Multivariate techniques were employed to investigate if there are discrete patterns of variation within Atripliceae. Principal Component Analyses (PCA) weakly differentiates four groups based on variation in pore number, puncta density per?µm², and ratio between spinule and puncta density per?µm²; species of Ceratocarpus, Haloxanthium, Krascheninnikovia, Manochlamys, Microgynoecium, Spinacia, and some species of Atriplex and Obione are isolated. Preliminary results indicate that pollen data are potentially useful in the classification of the tribe, and further studies will be of taxonomic value.