Soil-Borne Bacterial Structure and Diversity Does Not Reflect Community Activity in Pampa Biome

The Pampa biome is considered one of the main hotspots of the world’s biodiversity and it is estimated that half of its original vegetation was removed and converted to agricultural land and tree plantations. Although an increasing amount of knowledge is being assembled regarding the response of soil bacterial communities to land use change, to the associated plant community and to soil properties, our understanding about how these interactions affect the microbial community from the Brazilian Pampa is still poor and incomplete. In this study, we hypothesized that the same soil type from the same geographic region but under distinct land use present dissimilar soil bacterial communities. To test this hypothesis, we assessed the soil bacterial communities from four land-uses within the same soil type by 454-pyrosequencing of 16S rRNA gene and by soil microbial activity analyzes. We found that the same soil type under different land uses harbor similar (but not equal) bacterial communities and the differences were controlled by many microbial taxa. No differences regarding diversity and richness between natural areas and areas under anthropogenic disturbance were detected. However, the measures of microbial activity did not converge with the 16S rRNA data supporting the idea that the coupling between functioning and composition of bacterial communities is not necessarily correlated.     

Mast cell protease 5 mediates ischemia-reperfusion injury of mouse skeletal muscle

Ischemia with subsequent reperfusion (IR) injury is a significant clinical problem that occurs after physical and surgical trauma, myocardial infarction, and organ transplantation. IR injury of mouse skeletal muscle depends on the presence of both natural IgM and an intact C pathway. Disruption of the skeletal muscle architecture and permeability also requires mast cell (MC) participation, as revealed by the fact that IR injury is markedly reduced in c-kit defective, MC-deficient mouse strains. In this study, we sought to identify the pathobiologic MC products expressed in IR injury using transgenic mouse strains with normal MC development, except for the lack of a particular MC-derived mediator. Histologic analysis of skeletal muscle from BALB/c and C57BL/6 mice revealed a strong positive correlation (R(2) = 0.85) between the extent of IR injury and the level of MC degranulation. Linkage between C activation and MC degranulation was demonstrated in mice lacking C4, in which only limited MC degranulation and muscle injury were apparent. No reduction in injury was observed in transgenic mice lacking leukotriene C(4) synthase, hemopoietic PGD(2) synthase, N-deacetylase/N-sulfotransferase-2 (enzyme involved in heparin biosynthesis), or mouse MC protease (mMCP) 1. In contrast, muscle injury was significantly attenuated in mMCP-5-null mice. The MCs that reside in skeletal muscle contain abundant amounts of mMCP-5 which is the serine protease that is most similar in sequence to human MC chymase. We now report a cytotoxic activity associated with a MC-specific protease and demonstrate that mMCP-5 is critical for irreversible IR injury of skeletal muscle.     

Connexin 26 and 43 play a role in regulating proinflammatory events in the epidermis

Dysregulation of Connexin (CX) expression and function is associated with a range of chronic inflammatory conditions including psoriasis and nonhealing wounds. To mimic a proinflammatory environment, HaCaT cells, a model human keratinocyte cell line, were challenged with 10 µg/ml peptidoglycan (PGN) isolated from Staphylococcus aureus for 15 min to 24 hr in the presence or absence of CX blockers and/or following CX26, CX43, PANX1 and TLR2 small interfering RNA (siRNA) knockdown (KD). Expression levels of IL-6, IL-8, CX26, CX43, PANX1, TLR2 and Ki67 were assessed by quantitative real-time polymerase chain reaction, western blot analysis and/or immunocytochemistry. Nuclear factor kappa β (NF-κβ) was blocked with BAY 11-7082, CX-channel function was determined by adenosine 5′-triphosphate (ATP) release assays. Enzyme-linked immunosorbent assay monitored IL6 release following PGN challenge in the presence or absence of siRNA or blockers of CX or purinergic signalling. Exposure to PGN induced IL-6, IL-8, CX26 and TLR2 gene expression but it did not influence CX43, PANX1 or Ki67 messenger RNA expression levels. CX43 protein levels were reduced following 24 hr PGN exposure. PGN-induced CX26 and IL-6 expression were also aborted by TLR2-KD and inhibition of NF-κβ. ATP and IL-6 release were stimulated following 15 min and 1–24 hr challenge with PGN, respectively. Release of both agents was inhibited by coincubation with CX-channel blockers, CX26-, CX43- and TLR2-KD. The IL-6 response was also reduced by purinergic blockers. CX-signalling plays a role in the innate immune response in the epidermis. PGN is detected by TLR2, which via NF-κβ, directly activates CX26 and IL-6 expression. CX43 and CX26 maintain proinflammatory signalling by permitting ATP release, however, PANX1 does not participate.     

Micelle‐enhanced direct spectrofluorimetric method for the determination of linifanib: Application to stability studies

A new simple stability‐indicating spectrofluorimetric method has been developed and validated for the determination of the tyrosine kinase inhibitor, linifanib (LNF). The proposed method makes use of the native fluorescence characteristics of LNF in a micellar system. Compared with aqueous solutions, the fluorescence intensity of LNF was greatly enhanced upon the addition of Tween‐80. The relative fluorescence intensity of LNF was measured in a diluting solvent composed of 2% Tween‐80: phosphate buffer pH 8.0 (20: 80, v/v) using excitation and emission wavelengths of 290 and 450 nm, respectively. The proposed method was fully validated as per the ICH guidelines. The recorded fluorescence intensity of LNF was rectilinear over a concentration range of 0.3–2 μg/ml with a high correlation coefficient (r = 0.9990) and low limits of detection (0.091 μg/ml) and quantitation (0.275 μg/ml). The applicability of the method was extended to study the inherent stability of LNF under different stress degradation conditions including, alkaline, acidic, oxidative, photolytic and thermal degradation. Moreover, the method was utilized to study the kinetics of the alkaline and oxidative degradation of LNF. The pseudo‐first order rate constants and half‐lives were calculated.     

Phase-separated protein droplets of amyotrophic lateral sclerosis-associated p62/SQSTM1 mutants show reduced inner fluidity

Several amyotrophic lateral sclerosis (ALS)-related proteins such as FUS, TDP-43, and hnRNPA1 demonstrate liquid–liquid phase separation, and their disease-related mutations correlate with a transition of their liquid droplet form into aggregates. Missense mutations in SQSTM1/p62, which have been identified throughout the gene, are associated with ALS, frontotemporal degeneration (FTD), and Paget’s disease of bone. SQSTM1/p62 protein forms liquid droplets through interaction with ubiquitinated proteins, and these droplets serve as a platform for autophagosome formation and the antioxidative stress response via the LC3-interacting region (LIR) and KEAP1-interacting region (KIR) of p62, respectively. However, it remains unclear whether ALS/FTD-related p62 mutations in the LIR and KIR disrupt liquid droplet formation leading to defects in autophagy, the stress response, or both. To evaluate the effects of ALS/FTD-related p62 mutations in the LIR and KIR on a major oxidative stress system, the Keap1-Nrf2 pathway, as well as on autophagic turnover, we developed systems to monitor each of these with high sensitivity. These methods such as intracellular protein–protein interaction assay, doxycycline-inducible gene expression system, and gene expression into primary cultured cells with recombinant adenovirus revealed that some mutants, but not all, caused reduced NRF2 activation and delayed autophagic cargo turnover. In contrast, while all p62 mutants demonstrated sufficient ability to form liquid droplets, all of these droplets also exhibited reduced inner fluidity. These results indicate that like other ALS-related mutant proteins, p62 missense mutations result in a primary defect in ALS/FTD via a qualitative change in p62 liquid droplet fluidity.     

Shifts in soil bacterial community after eight years of land-use change

The interaction between plants, soil and microorganisms is considered to be the major driver of ecosystem functions and any modification of plant cover and/or soil properties might affect the microbial structure, which, in turn, will influence ecological processes. Assuming that soil properties are the major drivers of soil bacterial diversity and structure within the same soil type, it can be postulated whether plant cover causes significant shifts in soil bacterial community composition. To address this question, this study used 16S rRNA pyrosequencing to detect differences in diversity, composition and/or relative abundance of bacterial taxa from an area covered by pristine forest, as well as eight-year-old grassland surrounded by the same forest. It was shown that a total of 69% of the operational taxonomic units (OTUs) were shared between environments. Overall, forest and grassland samples presented the same diversity and the clustering analysis did not show the occurrence of very distinctive bacterial communities between environments. However, 11 OTUs were detected in statistically significant higher abundance in the forest samples but in lower abundance in the grassland samples, whereas 12 OTUs occurred in statistically significant higher abundance in the grassland samples but in lower abundance in the forest samples. The results suggested the prevalence of a resilient core microbial community that did not suffer any change related to land use, soil type or edaphic conditions. The results illustrated that the history of land use might influence present-day community structure.     

The first report of RNA U to C or G editing in the mitochondrial NADH dehydrogenase subunit 5 (Nad5) transcript of wild barley

Molecular Biology Reports - Nad dehydrogenase complex in mtDNA has a significant role in cellular respiration. One of the largest subunits in the complex is subunit 5 (Nad5). Four cDNAs of the...     

Paternal bisphenol A exposure induces testis and sperm pathologies in mice offspring: Possibly due to oxidative stress?

Bisphenol A (BPA), an endocrine and metabolic disruptor, is widely used to manufacture polycarbonate plastics and epoxy resins. Accumulating evidence suggests that paternal BPA exposure adversely affects male germlines and results in atypical reproductive phenotypes that might persist for generations to come. Our study investigated this exposure on testicular architecture and sperm quality in mouse offspring, and characterised underlying molecular mechanism(s). A total of 18 immature male Swiss albino mice (3.5 weeks old) were randomly divided into three groups and treated as follows: Group I, no treatment (sham control); Group II, sterile corn oil only (vehicle control); Group III, BPA (400 μg/kg) in sterile corn oil. At 9.5 weeks old, F0 males were mated with unexposed females. F0 offspring (F1 generation) were monitored for postnatal development for 10 weeks. At 11.5 weeks old, the animals were sacrificed to examine testicular architecture, sperm parameters, including DNA integrity, and oxidative stress biomarkers. Results showed that BPA significantly induced changes in the body and testis weights of the F0 and F1 generation BPA lineages compared to F0 and F1 generation control lineages. A decrease in sperm count and motility with further, increased sperm abnormalities, no or few sperm DNA alterations and elevated levels of MDA, PC and NO were recorded. Similar effects were found in BPA exposed F0 males, but were more pronounced in the F0 offspring. In addition, BPA caused alterations in the testicular architecture. These pathological changes extended transgenerationally to F1 generation males’ mice, but the pathological changes were more pronounced in the F1 generation. Our findings demonstrate that the biological and health BPA impacts do not end in paternal adults, but are passed on to offspring generations. Hence, linking observed testis and sperm abnormalities in the F1 generation to BPA exposure of their parental line was evident in this work. The findings also illustrate that oxidative stress appears to be a molecular component of the testis and sperm pathologies.