北方稻田生态系统研究 Ⅰ．稻萍结合系统的结构研究

经过连续５年的实验,研究了北方稻区稻萍结合系统的不同结构对细绿萍产量和水稻产量的影响．结果表明．随着萍种用量的增加,水田中萍的产量也明显增加;尽管宽窄行交替的水稻栽培结构也有利于萍产量的增加,但这样的结构可导致水稻减产３～７％．在北方单季稻地区建议采用３０ｃｍ等行距的水稻栽培方式和３２５ｋｇ·ｈｍ－２（湿重）的萍接种量建立的稻萍结合系统．     

Particle bombardment-mediated transient expression of a Brazil nut methionine-rich albumin in bean (Phaseolus vulgaris L.)

Bean (Phaseolus vulgaris L.) mature embryos were transformed using biolistic methods with a plasmid containing 2S albumin and -glucuronidase structural sequences, both under the control of the 35S CaMV promoter. We have shown that chimaeric tissues could be obtained and that both structural sequences were expressed to similar levels.     

Marqueurs du tractus génital et activités glycosidasiques séminales

Seminal liquefaction corresponds to a proteolysis of glycoproteins and could also result in a lysis of linked glycans involving glycosidases. It is well known that α-1-4 glucosidase is a real epipidymal marker. The aim of this study is to point out new markers among the glycosidases and especially β-D-mannosidase, α-L-fucosidase and N-acetyl-β-D-glucosaminidase. There is no correlation between the three enzymatic activities and the sperm count. Moreover in case of azoospermia enzymatic activities were always present. The variations observed are both quantitative (β-MAN activity is significantly decreased) and qualitative (modifications of the relative proportions of the different enzymatic forms) according to the etiology of azoospermia.     

Design and synthesis of 2,6-disubstituted-8-amino imidazo[1,2a]pyridines,a promising privileged structure

Imidazo[1,2a]pyridines have gained much interest in the field of medicinal chemistry research. In the aim of accessing new privileged structure, we decided to design and synthesize 8-aminated-imidazo[1,2a]pyridines substituted on positions 2 and 6. This scaffold, rarely found in the literature, was obtained via palladium-catalyzed coupling reactions (Suzuki reaction or N-hydroxysuccinimidyl activated ester method) and tested on adenosine receptor A_2A. We demonstrated how incorporation of an exocyclic amine enhanced affinity towards this receptor while maintaining low cytotoxicity.     

MARCH6 and TRC8 facilitate the quality control of cytosolic and tail‐anchored proteins

Misfolded or damaged proteins are typically targeted for destruction by proteasome‐mediated degradation, but the mammalian ubiquitin machinery involved is incompletely understood. Here, using forward genetic screens in human cells, we find that the proteasome‐mediated degradation of the soluble misfolded reporter, mCherry‐CL1, involves two ER‐resident E3 ligases, MARCH6 and TRC8. mCherry‐CL1 degradation is routed via the ER membrane and dependent on the hydrophobicity of the substrate, with complete stabilisation only observed in double knockout MARCH6/TRC8 cells. To identify a more physiological correlate, we used quantitative mass spectrometry and found that TRC8 and MARCH6 depletion altered the turnover of the tail‐anchored protein heme oxygenase‐1 (HO‐1). These E3 ligases associate with the intramembrane cleaving signal peptide peptidase (SPP) and facilitate the degradation of HO‐1 following intramembrane proteolysis. Our results highlight how ER‐resident ligases may target the same substrates, but work independently of each other, to optimise the protein quality control of selected soluble and tail‐anchored proteins.     

Feasibility study of stain-free classification of cell apoptosis based on diffraction imaging flow cytometry and supervised machine learning techniques

This study was to explore the feasibility of prediction and classification of cells in different stages of apoptosis with a stain-free method based on diffraction images and supervised machine learning. Apoptosis was induced in human chronic myelogenous leukemia K562 cells by cis-platinum (DDP). A newly developed technique of polarization diffraction imaging flow cytometry (p-DIFC) was performed to acquire diffraction images of the cells in three different statuses (viable, early apoptotic and late apoptotic/necrotic) after cell separation through fluorescence activated cell sorting with Annexin V-PE and SYTOX® Green double staining. The texture features of the diffraction images were extracted with in-house software based on the Gray-level co-occurrence matrix algorithm to generate datasets for cell classification with supervised machine learning method. Therefore, this new method has been verified in hydrogen peroxide induced apoptosis model of HL-60. Results show that accuracy of higher than 90% was achieved respectively in independent test datasets from each cell type based on logistic regression with ridge estimators, which indicated that p-DIFC system has a great potential in predicting and classifying cells in different stages of apoptosis.     

Oviposition site preference of Barbitistes vicetinus (Orthoptera,Tettigoniidae) during outbreaks

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Multi-scale turtle dove nest habitat selection in a Mediterranean agroforestry landscape: implications for the conservation of a vulnerable species

Determination of factors affecting nest habitat selection is a major topic in avian ecology, with strong implications for conservation purposes especially for the species with unfavorable status. The turtle dove (Streptopelia turtur) is a vulnerable species that has undergone a rapid and serious decline across its distribution range. I investigated the effect of different variables at two spatial scales (10-m radius, nest site; and 100-m radius, landscape) on the probability of presence of turtle dove nests in an agroforestry system of Central Morocco. Topography, habitat structure, human disturbance, and land use parameters were measured at nests (n?=?70) and random points (n?=?70) at both scales. Generalized linear model analyses showed that, at the nest site scale, tree height best explained occurrence of turtle dove nests (with nest occurring preferentially in smaller trees). At the landscape scale, nest occurrence probability decreased with elevation and distance to the nearest forest edge, and increased with forest cover and distance to the nearest habitation. Comparison of explanatory power of the single-scale models showed that the most relevant scale was the nest site level, followed by landscape scales, but the model including both nest-scale and landscape-scale variables was best. The variation partitioning analysis confirmed this pattern. In study area, the turtle dove nest habitat selection process occurs within a relatively small scale, but the joint effect of variables at the two scales is relevant. From a practical perspective, it would be interesting to reproduce the same experimental approach on other Mediterranean breeding habitats (agricultural and other forest habitats) to find out if this species would adopt the same nest habitat selection pattern.