Community composition and distribution of macroinvertebrates in the Umzimvubu River,South Africa: a pre-impoundment study

This paper presents baseline biological data on aquatic macroinvertebrates and water quality in the Umzimvubu River and selected tributaries, Eastern Cape Province, South Africa, prior to the construction of proposed large-scale water resource developments. Sampling was conducted seasonally at 14 sites between 1996 and 1998. The macroinvertebrate community composition was strikingly similar (±70%) across sites. Faunal diversity was low (104 taxa in total), but many taxa found were sensitive to water quality change (ASPT 5.0 to 9.6), indicating good water quality, which is attributed to the currently undeveloped nature of the catchment. Concentrations of water quality variables fell within a narrow range, except for total suspended solids, which at times was very high (up to 8 532mg l^–1). The highly variable concentration of the total suspended solids and its potential effects on biodiversity need to be investigated further. It is likely that bilharzia will spread and that pest blackflies may become a problem to livestock if the water resources become developed as is proposed. We suggest that more flow gauging weirs are needed to measure flows better for future management and also that the implications of the proposed developments on the estuary need to be investigated.     

Interplay between human microglia and neural stem/progenitor cells in an allogeneic co‐culture model

Experimental neural cell therapies, including donor neural stem/progenitor cells (NPCs) have been reported to offer beneficial effects on the recovery after an injury and to counteract inflammatory and degenerative processes in the central nervous system (CNS). The interplay between donor neural cells and the host CNS still to a large degree remains unclear, in particular in human allogeneic conditions. Here, we focused our studies on the interaction of human NPCs and microglia utilizing a co‐culture model. In co‐cultures, both NPCs and microglia showed increased survival and proliferation compared with mono‐cultures. In the presence of microglia, a larger subpopulation of NPCs expressed the progenitor cell marker nestin, whereas a smaller group of NPCs expressed the neural markers polysialylated neural cell adhesion molecule, A2B5 and glial fibrillary acidic protein compared with NPC mono‐cultures. Microglia thus hindered differentiation of NPCs. The presence of human NPCs increased microglial phagocytosis of latex beads. Furthermore, we observed that the expression of CD200 molecules on NPCs and the CD200 receptor protein on microglia was enhanced in co‐cultures, whereas the release of transforming growth factor‐β was increased suggesting anti‐inflammatory features of the co‐cultures. To conclude, the interplay between human allogeneic NPCs and microglia, significantly affected their respective proliferation and phenotype. Neural cell therapy including human donor NPCs may in addition to offering cell replacement, modulate host microglial phenotypes and functions to benefit neuroprotection and repair.     

Carbon Coated ZnFe2O4 Nanoparticles for Advanced Lithium‐Ion Anodes

The preparation and electrochemical characterization of a new material consisting of carbon coated ZnFe₂O₄ nanoparticles is presented. This material, which offers an interesting combination of alloying and conversion mechanisms, is capable of hosting up to nine equivalents of lithium per unit formula, corresponding to an exceptional specific capacity, higher than 1000 mAh g^?1. Composite electrodes of such a material, prepared using environmentally friendly sodium carboxymethyl cellulose as binder, showed the highest, ever reported, specific capacity and high rate performance upon long‐term testing. Furthermore, in situ X‐ray diffraction analysis allowed identifying the reduction process occurring upon initial lithiation.     

The First Report on Excellent Cycling Stability and Superior Rate Capability of Na3V2(PO4)3 for Sodium Ion Batteries

Sodium ion batteries are attractive for the rapidly emerging large‐scale energy storage market for intermittent renewable resources. Currently a viable cathode material does not exist for practical non‐aqueous sodium ion battery applications. Here we disclose a high performance, durable electrode material based on the 3D NASICON framework. Porous Na₃V₂(PO₄)₃/C was synthesized using a novel solution‐based approach. This material, as a cathode, is capable of delivering an energy storage capacity of ～400 mWh/g vs. sodium metal. Furthermore, at high current rates (10, 20 and 40 C), it displayed remarkable capacity retention. Equally impressive is the long term cycle life. Nearly 50% of the initial capacity was retained after 30,000 charge/discharge cycles at 40 C (4.7 A/g). Notably, coulombic efficiency was 99.68% (average) over the course of cycling. To the best of our knowledge, the combination of high energy density, high power density and ultra long cycle life demonstrated here has never been reported before for sodium ion batteries. We believe our findings will have profound implications for developing large‐scale energy storage systems for renewable energy sources.     

The yeast autophagy protease Atg4 is regulated by thioredoxin

Autophagy is a membrane-trafficking process whereby double-membrane vesicles called autophagosomes engulf and deliver intracellular material to the vacuole for degradation. Atg4 is a cysteine protease with an essential function in autophagosome formation. Mounting evidence suggests that reactive oxygen species may play a role in the control of autophagy and could regulate Atg4 activity but the precise mechanisms remain unclear. In this study, we showed that reactive oxygen species activate autophagy in the model yeast Saccharomyces cerevisiae and unraveled the molecular mechanism by which redox balance controls Atg4 activity. A combination of biochemical assays, redox titrations, and site-directed mutagenesis revealed that Atg4 is regulated by oxidoreduction of a single disulfide bond between Cys338 and Cys394. This disulfide has a low redox potential and is very efficiently reduced by thioredoxin, suggesting that this oxidoreductase plays an important role in Atg4 regulation. Accordingly, we found that autophagy activation by rapamycin was more pronounced in a thioredoxin mutant compared with wild-type cells. Moreover, in vivo studies indicated that Cys338 and Cys394 are required for the proper regulation of autophagosome biogenesis, since mutation of these cysteines resulted in increased recruitment of Atg8 to the phagophore assembly site. Thus, we propose that the fine-tuning of Atg4 activity depending on the intracellular redox state may regulate autophagosome formation.     

Isolation and characterization of isochorismate synthase and cinnamate 4-hydroxylase during salinity stress,wounding, and salicylic acid treatment in Carthamus tinctorius

Salicylic acid (SA) is a prominent signaling molecule during biotic and abiotic stresses in plants biosynthesized via cinnamate and isochorismate pathways. Cinnamate 4-hydroxylase (C4H) and isochorismate synthase (ICS) are the main enzymes in phenylpropanoid and isochorismate pathways, respectively. To investigate the actual roles of these genes in resistance mechanism to environmental stresses, here, the coding sequences of these enzymes in safflower (Carthamus tinctorius), as an oilseed industrial medicinal plant, were partially isolated and their expression profiles during salinity stress, wounding, and salicylic acid treatment were monitored. As a result, safflower ICS (CtICS) and C4H (CtC4H) were induced in early time points after wounding (3–6 h). Upon salinity stress, CtICS and CtC4H were highly expressed for the periods of 6–24 h and 3–6 h after treatment, respectively. It seems evident that ICS expression level is SA concentration dependent as if safflower treatment with 1 mM SA could induce ICS much stronger than that with 0.1 mM, while C4H is less likely to be so. Based on phylogenetic analysis, safflower ICS has maximum similarity to its ortholog in Vitis vinifera up to 69%, while C4H shows the highest similarity to its ortholog in Echinacea angustifolia up to 96%. Overall, the isolated genes of CtICS and CtC4H in safflower could be considered in plant breeding programs for salinity tolerance as well as for pathogen resistance.     

Differences in early callose deposition during adapted and non-adapted powdery mildew infection of resistant Arabidopsis lines

The deposition of callose, a (1,3)-β-glucan cell wall polymer, can play an essential role in the defense response to invading pathogens. We could recently show that Arabidopsis thaliana lines with an overexpression of the callose synthase gene PMR4 gained complete penetration resistance to the adapted powdery mildew Golovinomyces cichoracearum and the non-adapted powdery mildew Blumeria graminis f. sp hordei. The penetration resistance is based on the transport of the callose synthase PMR4 to the site of attempted fungal penetration and the subsequent formation of enlarged callose deposits. The deposits differed in their total diameter comparing both types of powdery mildew infection. In this study, further characterization of these callose deposits revealed that size differences were especially pronounced in the core region of the deposits. This suggests that specific, pathogen-dependent factors exist, which might regulate callose synthase transport to the core region of forming deposits.     

ATG4B promotes colorectal cancer growth independent of autophagic flux

Autophagy is reported to suppress tumor proliferation, whereas deficiency of autophagy is associated with tumorigenesis. ATG4B is a deubiquitin-like protease that plays dual roles in the core machinery of autophagy; however, little is known about the role of ATG4B on autophagy and proliferation in tumor cells. In this study, we found that ATG4B knockdown induced autophagic flux and reduced CCND1 expression to inhibit G₁/S phase transition of cell cycle in colorectal cancer cell lines, indicating functional dominance of ATG4B on autophagy inhibition and tumor proliferation in cancer cells. Interestingly, based on the genetic and pharmacological ablation of autophagy, the growth arrest induced by silencing ATG4B was independent of autophagic flux. Moreover, dephosphorylation of MTOR was involved in reduced CCND1 expression and G₁/S phase transition in both cells and xenograft tumors with depletion of ATG4B. Furthermore, ATG4B expression was significantly increased in tumor cells of colorectal cancer patients compared with adjacent normal cells. The elevated expression of ATG4B was highly correlated with CCND1 expression, consistently supporting the notion that ATG4B might contribute to MTOR-CCND1 signaling for G₁/S phase transition in colorectal cancer cells. Thus, we report that ATG4B independently plays a role as a positive regulator on tumor proliferation and a negative regulator on autophagy in colorectal cancer cells. These results suggest that ATG4B is a potential biomarker and drug target for cancer therapy.