Insight into Dominant Cellulolytic Bacteria from Two Biogas Digesters and Their Glycoside Hydrolase Genes

Diverse cellulolytic bacteria are essential for maintaining high lignocellulose degradation ability in biogas digesters. However, little was known about functional genes and gene clusters of dominant cellulolytic bacteria in biogas digesters. This is the foundation to understand lignocellulose degradation mechanisms of biogas digesters and apply these gene resource for optimizing biofuel production. A combination of metagenomic and 16S rRNA gene clone library methods was used to investigate the dominant cellulolytic bacteria and their glycoside hydrolase (GH) genes in two biogas digesters. The 16S rRNA gene analysis revealed that the dominant cellulolytic bacteria were strains closely related to Clostridium straminisolvens and an uncultured cellulolytic bacterium designated BG-1. To recover GH genes from cellulolytic bacteria in general, and BG-1 in particular, a refined assembly approach developed in this study was used to assemble GH genes from metagenomic reads; 163 GH-containing contigs ≥ 1 kb in length were obtained. Six recovered GH5 genes that were expressed in E. coli demonstrated multiple lignocellulase activities and one had high mannanase activity (1255 U/mg). Eleven fosmid clones harboring the recovered GH-containing contigs were sequenced and assembled into 10 fosmid contigs. The composition of GH genes in the 163 assembled metagenomic contigs and 10 fosmid contigs indicated that diverse GHs and lignocellulose degradation mechanisms were present in the biogas digesters. In particular, a small portion of BG-1 genome information was recovered by PhyloPythiaS analysis. The lignocellulase gene clusters in BG-1 suggested that it might use a possible novel lignocellulose degradation mechanism to efficiently degrade lignocellulose. Dominant cellulolytic bacteria of biogas digester possess diverse GH genes, not only in sequences but also in their functions, which may be applied for production of biofuel in the future.     

Efficacy of Oral Cryotherapy on Oral Mucositis Prevention in Patients with Hematological Malignancies Undergoing Hematopoietic Stem Cell Transplantation: A Meta-Analysis of Randomized Controlled Trials

Objectives

Controversy exists regarding whether oral cryotherapy can prevent oral mucositis (OM) in patients with hematological malignancies undergoing hematopoietic stem cell transplantation (HSCT). The aim of the present meta-analysis was to evaluate the efficacy of oral cryotherapy for OM prevention in patients with hematological malignancies undergoing HSCT.

Methods

PubMed and the Cochrane Library were searched through October 2014. Randomized controlled trials (RCTs) comparing the effect of oral cryotherapy with no treatment or with other interventions for OM in patients undergoing HSCT were included. The primary outcomes were the incidence, severity, and duration of OM. The secondary outcomes included length of analgesic use, total parenteral nutrition (TPN) use, and length of hospital stay.

Results

Seven RCTs involving eight articles analyzing 458 patients were included. Oral cryotherapy significantly decreased the incidence of severe OM (RR = 0.52, 95% CI = 0.27 to 0.99) and OM severity (SMD = -2.07, 95% CI = -3.90 to -0.25). In addition, the duration of TPN use and the length of hospitalization were markedly reduced (SMD = -0.56, 95% CI = -0.92 to -0.19; SMD = -0.44, 95% CI = -0.76 to -0.13; respectively). However, the pooled results were uncertain for the duration of OM and analgesic use (SMD = -0.13, 95% CI = -0.41 to 0.15; SMD = -1.15, 95% CI = -2.57 to 0.27; respectively).

Conclusions

Oral cryotherapy is a readily applicable and cost-effective prophylaxis for OM in patients undergoing HSCT.     

Proteomic Analysis of Seedling Roots of Two Maize Inbred Lines That Differ Significantly in the Salt Stress Response

Salinity is a major abiotic stress that limits plant productivity and quality throughout the world. Roots are the sites of salt uptake. To better understand salt stress responses in maize, we performed a comparative proteomic analysis of seedling roots from the salt-tolerant genotype F63 and the salt-sensitive genotype F35 under 160 mM NaCl treatment for 2 days. Under salinity conditions, the shoot fresh weight and relative water content were significantly higher in F63 than in F35, while the osmotic potential was significantly lower and the reduction of the K⁺/Na⁺ ratio was significantly less pronounced in F63 than in F35. Using an iTRAQ approach, twenty-eight proteins showed more than 2.0- fold changes in abundance and were regarded as salt-responsive proteins. Among them, twenty-two were specifically regulated in F63 but remained constant in F35. These proteins were mainly involved in signal processing, water conservation, protein synthesis and biotic cross-tolerance, and could be the major contributors to the tolerant genotype of F63. Functional analysis of a salt-responsive protein was performed in yeast as a case study to confirm the salt-related functions of detected proteins. Taken together, the results of this study may be helpful for further elucidating salt tolerance mechanisms in maize.     

Long-Term Over-Expression of Neuropeptide Y in Hypothalamic Paraventricular Nucleus Contributes to Adipose Tissue Insulin Resistance Partly via the Y5 Receptor

Intracerebroventricular injection and overexpression of Neuropeptide Y (NPY) in the paraventricular nucleus (PVN) has been shown to induce obesity and glucose metabolism disorder in rodents; however, the underlying mechanisms are still unclear. The aim of this study was to investigate the mechanism contributing to glucose metabolic disturbance induced by NPY. Recombinant lentiviral NPY vectors were injected into the PVN of rats fed a high fat (HFD) or low-fat diet. 8 weeks later, in vivo intravenous glucose tolerance tests and euglycemic-hyperinsulinemic clamp revealed that insulin resistance of adipose tissue were induced by NPY overexpression with or without HFD. NPY increased food intake, but did not change blood glucose, glycated hemoglobin A1c (HbA1c) or lipid levels. However, NPY decreased the expression of pGSK3β, PI3K p85 and pAKT^Ser473 in adipose tissue of rats. In vitro, 3T3-L1 adipocytes were treated with NPY, NPY Y1 and Y5 receptor antagonists. Glucose consumption and 2-deoxy-D-[³H] glucose uptake were partly inhibited by NPY, while a decrease in PI3K-AKT pathway signaling and a decreased expression of pGSK3α and pGSK3β were observed. Nevertheless, a Y5 receptor antagonist (L-152,804) reversed the effects of NPY on glucose uptake and consumption. These data suggest that long-term over-expression of NPY in PVN contributes to the establishment of adipose tissue insulin resistance, at least partly via the Y5 Receptor.     

Small RNA and Degradome Sequencing Reveal Complex Roles of miRNAs and Their Targets in Developing Wheat Grains

Plant microRNAs (miRNAs) have been shown to play critical roles in plant development. In this study, we employed small RNA combined with degradome sequencing to survey development-related miRNAs and their validated targets during wheat grain development. A total of 186 known miRNAs and 37 novel miRNAs were identified in four small RNA libraries. Moreover, a miRNA-like long hairpin locus was first identified to produce 21~22-nt phased siRNAs that act in trans to cleave target mRNAs. A comparison of the miRNAomes revealed that 55 miRNA families were differentially expressed during the grain development. Predicted and validated targets of these development-related miRNAs are involved in different cellular responses and metabolic processes including cell proliferation, auxin signaling, nutrient metabolism and gene expression. This study provides insight into the complex roles of miRNAs and their targets in regulating wheat grain development.     

Collective Motion in a Network of Self-Propelled Agent Systems

Collective motions of animals that move towards the same direction is a conspicuous feature in nature. Such groups of animals are called a self-propelled agent (SPA) systems. Many studies have been focused on the synchronization of isolated SPA systems. In real scenarios, different SPA systems are coupled with each other forming a network of SPA systems. For example, a flock of birds and a school of fish show predator-prey relationships and different groups of birds may compete for food. In this work, we propose a general framework to study the collective motion of coupled self-propelled agent systems. Especially, we study how three different connections between SPA systems: symbiosis, predator-prey, and competition influence the synchronization of the network of SPA systems. We find that a network of SPA systems coupled with symbiosis relationship arrive at a complete synchronization as all its subsystems showing a complete synchronization; a network of SPA systems coupled by predator-prey relationship can not reach a complete synchronization and its subsystems converges to different synchronized directions; and the competitive relationship between SPA systems could increase the synchronization of each SPA systems, while the network of SPA systems coupled by competitive relationships shows an optimal synchronization for small coupling strength, indicating that small competition promotes the synchronization of the entire system.     

Tetraarsenictetrasulfide and Arsenic Trioxide Exert Synergistic Effects on Induction of Apoptosis and Differentiation in Acute Promyelocytic Leukemia Cells

Since arsenic trioxide (As³⁺) has been successfully used in the treatment of acute promyelocytic leukemia (APL), its adverse effects on patients have been problematic and required a solution. Considering the good therapeutic potency and low toxicity of tetraarsenictetrasulfide (As₄S₄) in the treatment of APL, we investigated the effects of combining As₄S₄ and As³⁺ on the apoptosis and differentiation of NB4 and primary APL cells. As₄S₄, acting similarly to As³⁺, arrested the G₁/S transition, induced the accumulation of cellular reactive oxygen species, and promoted apoptosis. Additionally, low concentrations of As₄S₄ (0.1–0.4 μM) induced differentiation of NB4 and primary APL cells. Compared with the As₄S₄- or As³⁺-treated groups, the combination of As₄S₄ and As³⁺ obviously promoted apoptosis and differentiation of NB4 and primary APL cells. Mechanistic studies suggested that As₄S₄ acted synergistically with As³⁺ to down-regulate Bcl-2 and nuclear factor-κB expression, up-regulate Bax and p53 expression, and induce activation of caspase-12 and caspase-3. Moreover, the combination of low concentrations of As₄S₄ and As³⁺ enhanced degradation of the promyelocytic leukemia-retinoic acid receptor α oncoprotein. In summary, As₄S₄ and As³⁺ synergistically induce the apoptosis and differentiation of NB4 and primary APL cells.