Screening,cloning, enzymatic properties of a novel thermostable cellulase enzyme,and its potential application on water hyacinth utilization

International Microbiology - Cellulose is the cheapest, natural, renewable organic substance that is used as a carbon source in various fields. Water hyacinth, an aquatic plant rich in cellulose,...     

Coexistence and Pattern Formation in Bacterial Mixtures with Contact-Dependent Killing

Multistrain microbial communities often exhibit complex spatial organization that emerges because of the interplay of various cooperative and competitive interaction mechanisms. One strong competitive mechanism is contact-dependent neighbor killing enabled by the type VI secretion system. It has been previously shown that contact-dependent killing can result in bistability of bacterial mixtures so that only one strain survives and displaces the other. However, it remains unclear whether stable coexistence is possible in such mixtures. Using a population dynamics model for two interacting bacterial strains, we found that coexistence can be made possible by the interplay of contact-dependent killing and long-range growth inhibition, leading to the formation of various cellular patterns. These patterns emerge in a much broader parameter range than that required for the linear Turing-like instability, suggesting this may be a robust mechanism for pattern formation.     

MiRNA expression analysis of cancer-associated fibroblasts and normal fibroblasts in breast cancer

Cancer-associated fibroblasts (CAFs) promote tumorigenesis, growth, invasion and metastasis of cancer, whereas normal fibroblasts (NFs) are thought to suppress tumor progression. Little is known about miRNAs expression differences between CAFs and NFs or the patient-to-patient variability in miRNAs expression in breast cancer. We established primary cultures of CAFs and paired NFs from six resected breast tumor tissues that had not previously received radiotherapy or chemotherapy treatment and analyzed with miRNAs microarrays. The array data were analyzed using paired SAM t-test and filtered according to α and q values. Pathway analysis was conducted using DAVID v6.7. We identified 11 dysregulated miRNAs in CAFs: three were up-regulated (miR-221-5p, miR-31-3p, miR-221-3p), while eight were down-regulated (miR-205, miR-200b, miR-200c, miR-141, miR-101, miR-342-3p, let-7g, miR-26b). Their target genes are known to affect cell differentiation, adhesion, migration, proliferation, secretion and cell-cell interaction. By our knowledge it is firstly identify the expression profiles of miRNAs between CAFs and NFs and revealed their regulation on the associated signaling pathways.     

Schistosome infection promotes osteoclast-mediated bone loss

Infection with schistosome results in immunological changes that might influence the skeletal system by inducing immunological states affecting bone metabolism. We investigated the relationships between chronic schistosome infection and bone metabolism by using a mouse model of chronic schistosomiasis, affecting millions of humans worldwide. Results showed that schistosome infection resulted in aberrant osteoclast-mediated bone loss, which was accompanied with an increased level of receptor activator of nuclear factor-κB (NF-κB) Ligand (RANKL) and decreased level of osteoprotegerin (OPG). The blockade of RANKL by the anti-RANKL antibody could prevent bone loss in the context of schistosome infection. Meanwhile, both B cells and CD4⁺ T cells, particularly follicular helper T (Tfh) cell subset, were the important cellular sources of RANKL during schistosome infection. These results highlight the risk of bone loss in schistosome-infected patients and the potential benefit of coupling bone therapy with anti-schistosome treatment.     

Kinetics of manganese transport and gene expressions of manganese transport carriers in Caco-2 cell monolayers

Two experiments were conducted to investigate the kinetics of manganese (Mn) transport in Caco-2 cell monolayers and the gene expressions of Mn transport carriers in apical (AP) and basolateral (BL) membranes. In experiment 1, the cells were treated with the medium containing 146 μmol/L of Mn (MnSO₄·H₂O). Both the uptake and transport of Mn from AP–BL or from BL–AP at different time-points were assessed to determine the optimal time for kinetics of Mn transport. The transport of Mn increased linearly with higher efficiency values in AP–BL than in BL–AP direction, however, the uptake of Mn revealed an asymptotic pattern within 120 min. In experiment 2, the kinetics of Mn transport in AP–BL was determined with media containing Mn concentrations from 0 to 2,500 μmol/L at 40 and 120 min, respectively, and mRNA levels of divalent metal transporter 1 (DMT1) and ferroportin (FPN1) were determined in Caco-2 cells treated with the medium containing 0 or 800 μmol/L of Mn for 120 min. The kinetics of Mn transport showed a carrier-mediated process when Mn concentrations were lower than 1,000 μmol/L and a linear increment when Mn concentrations exceeded 1,000 μmol/L at either 40 or 120 min. Mn treatment decreased (P < 0.01) DMT1 mRNA level and increased (P < 0.01) FPN1 mRNA level. The results from the present study suggested that Mn transport in AP–BL fit both carrier-mediated saturable and non-saturable diffusion processes, and Mn transport carriers DMT1 and FPN1 mediate the apical uptake and basolateral exit of Mn in Caco-2 cells.     

Heterogeneous nutrient supply promotes maize growth and phosphorus acquisition: additive and compensatory effects of lateral roots and root hairs

Background and AimsRoot proliferation is a response to a heterogeneous nutrient distribution. However, the growth of root hairs in response to heterogeneous nutrients and the relationship between root hairs and lateral roots remain unclear. This study aims to understand the effects of heterogeneous nutrients on root hair growth and the trade-off between root hairs and lateral roots in phosphorus (P) acquisition.MethodsNear-isogenic maize lines, the B73 wild type (WT) and the rth3 root hairless mutant, were grown in rhizoboxes with uniform or localized supply of 40 (low) or 140 (high) mg P kg⁻¹ soil.ResultsBoth WT and rth3 had nearly two-fold greater shoot biomass and P content under local than uniform treatment at low P. Significant root proliferation was observed in both WT and rth3 in the nutrient patch, with the WT accompanied by an obvious increase (from 0.7 to 1.2 mm) in root hair length. The root response ratio of rth3 was greater than that of WT at low P, but could not completely compensate for the loss of root hairs. This suggests that plants enhanced P acquisition through complementarity between lateral roots and root hairs, and thus regulated nutrient foraging and shoot growth. The disappearance of WT and rth3 root response differences at high P indicated that the P application reduced the dependence of the plants on specific root traits to obtain nutrients.ConclusionsIn addition to root proliferation, the root response to a nutrient-rich patch was also accompanied by root hair elongation. The genotypes without root hairs increased their investment in lateral roots in a nutrient-rich patch to compensate for the absence of root hairs, suggesting that plants enhanced nutrient acquisition by regulating the trade-off of complementary root traits.     

Roemerine Improves the Survival Rate of Septicemic BALB/c Mice by Increasing the Cell Membrane Permeability of Staphylococcus aureus

Staphylococcus aureus is one of the most frequently occurring hospital- and community-associated pathogenic bacteria featuring high morbidity and mortality. The occurrence of methicillin-resistant S. aureus (MRSA) has increased persistently over the years. Therefore, developing novel anti-MRSA drugs to circumvent drug resistance of S. aureus is highly important. Roemerine, an aporphine alkaloid, has previously been reported to exhibit antibacterial activity. The present study aimed to investigate whether roemerine can maintain these activities against S.aureus in vivo and further explore the underlying mechanism. We found that roemerine is effective in vitro against four S. aureus strains as well as in vivo against MRSA insepticemic BALB/c mice. Furthermore, roemerine was found to increase cell membrane permeability in a concentration-dependent manner. These findings suggest that roemerine may be developed as a promising compound for treating S. aureus, especially methicillin-resistant strains of these bacteria.     

Photoactivation studies of zinc porphyrin-myoglobin system and its application for light-chemical energy conversion

An artificial zinc porphyrin-myoglobin-based photo-chemical energy conversion system, consisting of ZnPP-Mb or ZnPE(1)-Mb as a photosensitizer, NADP(+) as an electron acceptor, and triethanolamine as an electron donor, has been constructed to mimic photosystem I. The photoirradiated product is able to reduce a single-electron acceptor protein cytochrome c, but cannot catalyze the two-electron reduction of acetaldehyde by alcohol dehydrogenase, thus demonstrating a single electron transfer mechanism. Furthermore, the artificial system can bifunctionally promote oxidoredox reactions, depending on the presence or absence of a sacrificial electron donor, thus suggesting its potential application in electrochemical regeneration steps involved in chemical transformation and/or energy conversion.     

Temporal and Spatial Dynamics of Carbon Fixation by Moso Bamboo (<Emphasis Type="BoldItalic">Phyllostachys pubescens</Emphasis>) in Subtropical China

To study the temporal and spatial dynamics of carbon fixation by Moso bamboo (Phyllostachys pubescens) in subtropical China, carbon fixation of leaves within the canopy of P. pubescens was measured with a LI-6400 portable photosynthesis system. The results showed that the capability of carbon fixation of P. pubescens leaves had obvious temporal and spatial dynamic variations. It was revealed that there were two peak periods and two low periods in the season variation of carbon fixation capability. Data also revealed that the capability of carbon fixation by five-year-old P. pubescens was more than that of one-year-old and three-year-old. Daily and seasonal carbon fixation showed a negative correlation with the CO₂ concentration. The temporal and spatial dynamics of carbon fixation by P. pubescens described above provided a scientific basis for development of technologies in bamboo timber production.     

Complete genome sequence of Methanosaeta concilii, a specialist in aceticlastic methanogenesis

The genome sequence of the aceticlastic methanoarchaeon Methanosaeta concilii GP6, comprised of a 3,008,626-bp chromosome and an 18,019-bp episome, has been determined and exhibits considerable differences in gene content from that of Methanosaeta thermophila.