Supramolecular aggregation of aquaporin‐4 is different in muscle and brain: correlation with tissue susceptibility in neuromyelitis optica

Neuromyelitis optica (NMO) is an autoimmune demyelinating disease of the central nervous system (CNS) caused by autoantibodies (NMO‐IgG) against the water channel aquaporin‐4 (AQP4). Though AQP4 is also expressed outside the CNS, for example in skeletal muscle, patients with NMO generally do not show clinical/diagnostic evidence of skeletal muscle damage. Here, we have evaluated whether AQP4 supramolecular organization is at the basis of the different tissue susceptibility. Using immunofluorescence we found that while the sera of our cohort of patients with NMO gave typical perivascular staining in the CNS, they were largely negative in the skeletal muscle. This conclusion was obtained using human, rat and mouse skeletal muscle including the AQP4‐KO mouse. A biochemical analysis using a new size exclusion chromatography approach for AQP4 suprastructure fractionation revealed substantial differences in supramolecular AQP4 assemblies and isoform abundance between brain and skeletal muscle matching a lower binding affinity of NMO‐IgG to muscle compared to the brain. Super‐resolution microscopy analysis with g‐STED revealed different AQP4 organization in native tissues, while in the brain perivascular astrocyte endfoot membrane AQP4 was mainly organized in large interconnected and raft‐like clusters, in the sarcolemma of fast‐twitch fibres AQP4 aggregates often appeared as small, relatively isolated linear entities. In conclusion, our results provide evidence that AQP4 supramolecular structure is different in brain and skeletal muscle, which is likely to result in different tissues susceptibility to the NMO disease.     

Photobiomodulation of a flowable matrix in a human skin ex vivo model demonstrates energy‐based enhancement of engraftment integration and remodeling

The use of dermal substitutes to treat skin defects such as ulcers has shown promising results, suggesting a potential role for skin substitutes for treating acute and chronic wounds. One of the main drawbacks with the use of dermal substitutes is the length of time from engraftment to graft take, plus the risk of contamination and failure due to this prolonged integration. Therefore, the use of adjuvant energy‐based therapeutic modalities to augment and accelerate the rate of biointegration by dermal substitute engraftments is a desirable outcome. The photobiomodulation (PBM) therapy modulates the repair process, by stimulating cellular proliferation and angiogenesis. Here, we evaluated the effect of PBM on a collagen‐glycosaminoglycan flowable wound matrix (FWM) in an ex vivo human skin wound model. PBM resulted in accelerated rate of re‐epithelialization and organization of matrix as seen by structural arrangement of collagen fibers, and a subsequent increased expression of alpha‐smooth muscle actin (α‐SMA) and vascular endothelial growth factor A (VEGF‐A) leading to an overall improved healing process. The use of PBM promoted a beneficial effect on the rate of integration and healing of FWM. We therefore propose that the adjuvant use of PBM may have utility in enhancing engraftment and tissue repair and be of value in clinical practice.      

Evaluation of pest control efficiencies for different banker plant systems with a simple predator–prey model

The banker plant system has been introduced for the biological control of various pest species in Japanese greenhouses. With the banker plant system, non-crop plants infested with a host insect (a non-commercial crop pest) are placed in the greenhouse to provide alternative resources for the parasitoids or predators. We want to evaluate the effectiveness for controlling pests on the crop in a quantitative way by immigrating predators from the banker plant. Therefore, we developed a simple model for the interaction of the pest and predator in the crop and included the banker plant only as a source for predators. For three different pest-predator systems we parameterised the model and used these models to predict under what conditions biological control in a banker plant system is successful. We defined successful as keeping the pest below the economic injury level of the crop estimated from damage analysis. Because the crop is mostly grown during a period that lasts less than a year our analysis should not only focus on the equilibrium dynamics. In contrast, it should also focus on the transient dynamics. Our main analytical result, from the equilibrium analysis, is that for successful control the maximum lifetime consumption of immigrating predators should exceed the daily prey growth at half the value of the maximum consumption rate. For practical purpose this translates into the fact that the immigration of predators at a low initial pest density is crucial for successful control.     

激光对尾草履虫分裂繁殖影响的研究

采用Ｈｅ－Ｎｅ激光辐照经单克隆培养的尾草履虫（Ｐａｒａｍｅｃｉｕｍｃａｕａｔｕｍ）无性繁殖系,观察并分析激光对尾草履虫分裂繁殖产生的影响,结果表明,在本实验条件下,当辐照的能量密度处于５０．９－１０１．９（Ｊ／ｃｍ＾２）范围内,激光对尾草履虫的分裂繁殖产生促进作用,当辐照的能量密度为１０１．９Ｊ／ｃｍ＾２时,草履虫分裂繁殖的个体平均数达最大值。草履虫对激光辐照有很大的耐受范围和很强的耐受能力。本实     

Early hominid physical evolution

Hindrances against bipedalism evolution are localized in obstetrical constraints, maternal mortality rates, infant birth trauma and unsafe pregnancy. Analysis of infant survival probability shows that a shift to bipedalism could occur as a necessary consequence of the process of body fur reduction, in a balance between such hindrances and safe infant transportation. Fur reduction is proposed to correlate with cooling mechanism in intra-species physical fights. The triggering of a feed-back mechanism connecting reduction of body fur to canine reduction would be responsible for a passage from threat displays to actual physical fights. The proposed scenario for such changes is the transition from uni-male to multi-male social structures among Hominoidea. The implications of the approach adopted are discussed.     

Biochemical complexity of serum HLA class I molecules

Human serum was found to contain a variety of class I-like molecules by Western blotting with anti-class I heavy chain reagents: major bands usually are observed around M _r 44 000, 40 000, and 35 000–37 000. HLA-A24-positive individuals are distinguished by higher serum levels of M _r 44 000 and 40 000 class I-like molecules than those found in HLA-A24-negative individuals. The M _r 44 000 serum molecules are probably intact class I molecules that have been shed from the cell membrane, because they contain both a transmembrane segment (TM), as deduced from detergent-binding experiments, and a cytoplasmic tail (CT), as inferred from reactivity with an antipeptide serum specific for the cytoplasmic domain of class I antigens (RaCT). The M _r 35 000 and 37 000 molecules contain neither a TM nor a CT region and therefore are probably proteolytic breakdown products of cellular and/or serum M _r 44 000 molecules, although the existence of Q10-like molecules in man cannot be ruled out. The M _r 40 000 molecules do not contain a TM region. M _r 40 000 molecules reactive with the RaCT serum were found in the minority (2/13) of sera tested. We conclude that alternative splicing resulting in a precise excision of the TM exon plays a minor role in the generation of serum HLA class I antigens.Abbreviations used in this paper B2m beta-2 microglobulin - BSA bovine serum albumin - EBV-BLCL Epstein-Barr virus-transformed B lymphoblastoid cell line - mAb monoclonal antibody - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis - TCA trichloroacetic acid     

Evolution of the visual sensory system in cichlid fishes from crater lake Barombi Mbo in Cameroon

In deep‐water animals, the visual sensory system is often challenged by the dim‐light environment. Here, we focus on the molecular mechanisms involved in rapid deep‐water adaptations. We examined visual system evolution in a small‐scale yet phenotypically and ecologically diverse adaptive radiation, the species flock of cichlid fishes in deep crater lake Barombi Mbo in Cameroon, West Africa. We show that rapid adaptations of the visual system to the novel deep‐water habitat primarily occurred at the level of gene expression changes rather than through nucleotide mutations, which is compatible with the young age of the radiation. Based on retinal bulk RNA sequencing of all eleven species, we found that the opsin gene expression pattern was substantially different for the deep‐water species. The nine shallow‐water species feature an opsin palette dominated by the red‐sensitive (LWS) opsin, whereas the two unrelated deep‐water species lack expression of LWS and the violet‐sensitive (SWS2B) opsin, thereby shifting the cone sensitivity to the centre of the light spectrum. Deep‐water species further predominantly express the green‐sensitive RH2Aα over RH2Aβ. We identified one amino acid substitution in the RH2Aα opsin specific to the deep‐water species. We finally performed a comparative gene expression analysis in retinal tissue of deep‐ vs. shallow‐water species. We thus identified 46 differentially expressed genes, many of which are associated with functions in vision, hypoxia management or circadian clock regulation, with some of them being associated with human eye diseases.