重庆三峡库区柑橘硼营养状况及其影响因子

为了解重庆三峡库区柑橘叶片硼营养状况及其影响因子,在该区域12个主产县(区)的代表性果园采集叶片样品954份和土壤样品302份,测定叶片硼含量,并分析了土壤有效硼、土壤pH值、品种、砧木和树龄对叶片硼营养的影响.结果表明: 该区域柑橘叶片硼含量不足(<35 mg·kg^-1)的果园比例达41.6%,土壤有效硼含量不足(<0.5 mg·kg^-1)的果园比例高达89.4%,柑橘叶片硼含量与土壤有效硼含量的相关性未达显著水平.土壤pH值、品种、砧木和树龄均影响叶片硼含量.pH值4.5～6.4土壤上的柑橘叶片硼含量显著高于pH值6.5～8.5土壤上的柑橘;品种间叶片硼含量为:温州蜜柑>柚类>夏橙>普通甜橙>杂柑>脐橙;枳砧和酸柚砧柑橘叶片硼含量显著高于枳橙砧和红橘砧柑橘;3～8年生柑橘树叶片硼含量适宜(35～100 mg·kg^-1)样品比例比8年生以上柑橘树高6.6%.     

A C. elegans homolog of the Cockayne syndrome complementation group A gene

Cockayne syndrome (CS) is a debilitating and complex disorder that results from inherited mutations in the CS complementation genes A and B, CSA and CSB. The links between the molecular functions of the CS genes and the complex pathophysiology of CS are as of yet poorly understood and are the subject of intense debate. While mouse models reflect the complexity of CS, studies on simpler genetic models might shed new light on the consequences of CS mutations. Here we describe a functional homolog of the human CSA gene in Caenorhabditis elegans. Similar to its human counterpart, mutations in the nematode csa-1 gene lead to developmental growth defects as a consequence of DNA lesions.     

Spatial and temporal habitat use and selection by red deer: The use of direct and indirect methods

Given the importance of red deer Cervus elaphus for hunting and conservation purposes, understanding the interactions between this species and its habitats in the Mediterranean region is a crucial step for the sustainable management of this species. Aiming to compare pellet group counts and direct observations methods to study the habitat use and selection by red deer, the results obtained by both methods were compared, and their advantages and disadvantages were discussed. To understand the temporal patterns of habitat use and selection, the survey was conducted at three different seasons, birth period, rut season and winter. The habitat use and selection were studied in relation to land cover, watercourse, roads, ecotone zones and other topographic features (altitude, slope and aspect), using generalized linear models and selection ratios. The similarity of the results provided by pellet group counts and direct observations indicate that both methods may constitute useful tools to study the habitat use and selection by red deer. Globally, red deer seemed to select habitats that provide simultaneously food and some cover, as shown by its preference for shrublands, independently of the sampling season. The positive selection of ecotone zones embodies the need for open spaces. Males and females showed a similar use of shrubland, but selected patches with different characteristics therein. The spatial and temporal patterns exhibited by our results suggest that red deer balance their habitat requirements in respect to each phase of their reproductive cycle. Pellet group counts and direct observations seem to be useful methods to analyze habitat use and selection, and may provide helpful knowledge to the management and conservation of red deer.     

Avanti lipid tools: Connecting lipids,technology, and cell biology

Lipid research is challenging owing to the complexity and diversity of the lipidome. Here we review a set of experimental tools developed for the seasoned lipid researcher, as well as, those who are new to the field of lipid research. Novel tools for probing protein–lipid interactions, applications for lipid binding antibodies, enhanced systems for the cellular delivery of lipids, improved visualization of lipid membranes using gold-labeled lipids, and advances in mass spectrometric analysis techniques will be discussed. Because lipid mediators are known to participate in a host of signal transduction and trafficking pathways within the cell, a comprehensive lipid toolbox that aids the science of lipidomics research is essential to better understand the molecular mechanisms of interactions between cellular components. This article is part of a Special Issue entitled Tools to study lipid functions.     

The evolution of centipede venom claws – Open questions and possible answers

The maxilliped venom claw is an intriguing structure in centipedes. We address open questions concerning this structure. The maxillipeds of fossil centipedes from the Carboniferous (about 300 million years old) have been described, but not been depicted previously. Re-investigation demonstrates that they resemble their modern counterparts. A Jurassic geophilomorph centipede (about 150 million years old) was originally described as possessing a rather leg-like maxilliped. Our re-investigation shows that the maxilliped is, in fact, highly specialized as in modern Geophilomorpha. A scenario for the evolution of the centipede maxilliped is presented. It supports one of the two supposed hypotheses of centipede phylogeny, the Pleurostigmophora hypothesis. Although this hypothesis appears now well established, many aspects of character evolution resulting from this phylogeny remain to be told in detail. One such aspect is the special joint of the maxilliped in some species of Cryptops. Cryptops is an in-group of Scolopendromorpha, but its maxilliped joint can resemble that of Lithobiomorpha or even possess a mixture of characters between the both. Detailed investigation of fossils, larger sample sizes of extant species, and developmental data will be necessary to allow further improvements of the reconstruction of the evolutionary history of centipedes.     

Mechanisms of cohesin-mediated gene regulation and lessons learned from cohesinopathies

Cohesins are conserved and essential Structural Maintenance of Chromosomes (SMC) protein-containing complexes that physically interact with chromatin and modulate higher-order chromatin organization. Cohesins mediate sister chromatid cohesion and cellular long-distance chromatin interactions affecting genome maintenance and gene expression. Discoveries of mutations in cohesin's subunits and its regulator proteins in human developmental disorders, so-called “cohesinopathies,” reveal crucial roles for cohesins in development and cellular growth and differentiation. In this review, we discuss the latest findings concerning cohesin's functions in higher-order chromatin architecture organization and gene regulation and new insight gained from studies of cohesinopathies. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.