Depth distributions of Fucus vesiculosus L. and Zostera marina L. as classification parameters for implementing the European Water Framework Directive on the German Baltic coast

A classification approach was developed within the European Water Framework Directive for the outer coastal waters of the German Baltic Sea. We concentrated on the known recent presence and depth distribution of Zostera marina and Fucus vesiculosus along the German coast. According to the European Water Framework Directive the reference conditions were reconstructed based on historical data. The available databases indicate that both species formerly occurred down to 10 m depth along the whole German Baltic Sea coastline, independent on the salinity gradient. The recent depth distribution of Z. marina varied between 2.5 and 7.9 m along the German Baltic coast. Dense F. vesiculosus stands were observed only along the western part of this coast at a maximum depth of 4.7 m. Comparing the historical data sets with recent findings reveals a strong decline of depth limits for both species during the last century. Therefore, we used both species to describe the degradation of the Baltic Sea coastal waters using change in the depth distribution. The boundaries of the ecological status according to the Water Framework Directive were calculated based on modelling. Ecophysiological light demands of species and decrease of water transparency (light reduction in percent) were used to describe the degradations. This approach is robust against variation of macrophyte light requirements and is straightforward to classify recent long-term macrophyte monitoring. However, it is very sensitive against changes in the depth distribution and may result in erroneous estimations of ecological class boundaries when insufficient historical data are used as reference. This model allows the adaption of the boundaries calculations to new knowledge about historical data and ecophysiological light demand of plants. Actually, the boundaries of the classification were defined as follows: 1% light reduction represents the transition from high/pristine to good ecological status, and 5% indicates the transition from good to moderate status. At least 25% reduction corresponds to a poor status, more than 75% to a bad status.     

东亚飞蝗hunchback基因在卵子形成和胚胎发育过程中的原位表达

hb（hunchback）基因是昆虫胚胎前后轴模式形成的关键基因．对东亚飞蝗（Locusta migratoria manilensis,Meyen）hb基因的功能已有报道,但其表达模式还不清楚．为了研究胁基因在东亚飞蝗卵子形成和胚胎发育过程中的时空表达情况,本研究采用免疫组化方法在蛋白质水平上检测了hb基因的时空表达模式．在卵子形成过程中,hb基因局限在卵细胞核区中表达,随着卵子的发育逐渐移至卵细胞的后端;卵受精后,核区里的Hb蛋白向外扩散,在卵后端形成浓度梯度;胚盘期,hb基因在胚盘中央呈带状表达;胚盘分化为原头和原躯干后,表达条带变宽,并呈现出梯度表达,该表达区域将形成颌、胸部的部分体节;随着腹节开始形成,hb基因在颌胸部的表达逐渐减弱,而在腹部后端的“生长区”表达,并呈现出不连续性．经比较,hb易基因在昆虫颌胸部的表达较为保守,而在卵子形成过程中和腹部的表达具有较大的变异性．与黑腹果蝇等长胚带昆虫相比,东亚飞蝗hb基因在体节形成的基因级联调控中具有更重要、更直接的调控作用．     

Genetic tailoring of N-linked oligosaccharides: the role of glucose residues in glycoprotein processing of Saccharomyces cerevisiae in vivo

In higher eukaryotes a quality control system monitoring the folding state of glycoproteins is located in the ER and is composed of the proteins calnexin, calreticulin, glucosidase II, and UDP-glucose: glycoprotein glucosyltransferase. It is believed that the innermost glucose residue of the N- linked oligosaccharide of a glycoprotein serves as a tag in this control system and therefore performs an important function in the protein folding pathway. To address this function, we constructed Saccharomyces cerevisiae strains which contain nonglucosylated (G0), monoglucosylated (G1), or diglucosylated (G2) glycoproteins in the ER and used these strains to study the role of glucose residues in the ER processing of glycoproteins. These alterations of the oligosaccharide structure did not result in a growth phenotype, but the induction of the unfolded protein response upon treatment with DTT was much higher in G0 and G2 strains as compared to wild-type and G1 strains. Our results provide in vivo evidence that the G1 oligosaccharide is an active oligosaccharide structure in the ER glycoprotein processing pathway of S.cerevisiae. Furthermore, by analyzing N- linked oligosaccharides of the constructed strains we can directly show that no general glycoprotein glucosyltransferase exists in S. cerevisiae.      

人肺腺癌细胞分化相关基因cDNAs的克隆

在用10^-5 mol/L全反式维甲酸(RA)诱导人肺腺癌细胞系GLC-82分化的基础上,以M13噬菌粒pSPORT1为载体,应用定向克隆技术,分别构建了未经RA诱导和RA诱导1d及4d细胞的3个cDNA文库.以含重组子的诱导文库单链DNA为靶标(Target)同未诱导文库的cDNA驱除子(Driver)进行消减杂交,富集RA特异性单链DNA,将富集的单链DNA回复为双链后转化感受态菌,建立细胞诱导分化过程中活化表达基因的cDNA消减文库,得到124个cDNA消减克隆.经同源性分析和与文库总cDNA作Southern印迹杂交,进而与RA诱导前后细胞的RNA作Northern印迹杂交,筛选出2个(RA5,RA28)诱导后呈早期瞬时表达和1个(RA42)呈早期并持续表达的cDNA克隆,cDNA全长分别为1.8,1.5和0.7kb.序列测定及初步功能分析结果表明,RA5,RA28和RA42这3个首次报道的序列,可能是人肺腺癌细胞分化相关基因的cDNA克隆.     

Global transcriptional response of pig brain and lung to natural infection by Pseudorabies virus

Background  

Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult.     

Molecular evolution of olfactomedin

Olfactomedin is a secreted polymeric glycoprotein of unknown function,originally discovered at the mucociliary surface of the amphibian olfactoryneuroepithelium and subsequently found throughout the mammalian brain. As afirst step toward elucidating the function of olfactomedin, itsphylogenetic history was examined to identify conserved structural motifs.Such conserved motifs may have functional significance and provide targetsfor future mutagenesis studies aimed at establishing the function of thisprotein. Previous studies revealed 33% amino acid sequence identity betweenrat and frog olfactomedins in their carboxyl terminal segments. Furtheranalysis, however, reveals more extensive homologies throughout themolecule. Despite significant sequence divergence, cysteines essential forhomopolymer formation such as the CXC motif near the amino terminus areconserved, as is the characteristic glycosylation pattern, suggesting thatthese posttranslational modifications are essential for function.Furthermore, evolutionary analysis of a region of 53 amino acids of fish,frog, rat, mouse, and human olfactomedins indicates that an ancestralolfactomedin gene arose before the evolution of terrestrial vertebrates andevolved independently in teleost, amphibian, and mammalian lineages.Indeed, a distant olfactomedin homolog was identified in Caenorhabditiselegans. Although the amino acid sequence of this invertebrate protein islonger and highly divergent compared with its vertebrate homologs, theprotein from C. elegans shows remarkable similarities in terms of conservedmotifs and posttranslational modification sites. Six universally conservedmotifs were identified, and five of these are clustered in the carboxylterminal half of the protein. Sequence comparisons indicate that evolutionof the N-terminal half of the molecule involved extensive insertions anddeletions; the C-terminal segment evolved mostly through point mutations,at least during vertebrate evolution. The widespread occurrence ofolfactomedin among vertebrates and invertebrates underscores the notionthat this protein has a function of universal importance. Furthermore,extensive modification of its N-terminal half and the acquisition of aC-terminal SDEL endoplasmic-reticulum- targeting sequence may have enabledolfactomedin to adopt new functions in the mammalian central nervoussystem.     

The draft genome of the pest tephritid fruit fly Bactrocera tryoni: resources for the genomic analysis of hybridising species

Background

The tephritid fruit flies include a number of economically important pests of horticulture, with a large accumulated body of research on their biology and control. Amongst the Tephritidae, the genus Bactrocera, containing over 400 species, presents various species groups of potential utility for genetic studies of speciation, behaviour or pest control. In Australia, there exists a triad of closely-related, sympatric Bactrocera species which do not mate in the wild but which, despite distinct morphologies and behaviours, can be force-mated in the laboratory to produce fertile hybrid offspring. To exploit the opportunities offered by genomics, such as the efficient identification of genetic loci central to pest behaviour and to the earliest stages of speciation, investigators require genomic resources for future investigations.

Results

We produced a draft de novo genome assembly of Australia’s major tephritid pest species, Bactrocera tryoni. The male genome (650 -700 Mbp) includes approximately 150Mb of interspersed repetitive DNA sequences and 60Mb of satellite DNA. Assessment using conserved core eukaryotic sequences indicated 98% completeness. Over 16,000 MAKER-derived gene models showed a large degree of overlap with other Dipteran reference genomes. The sequence of the ribosomal RNA transcribed unit was also determined. Unscaffolded assemblies of B. neohumeralis and B. jarvisi were then produced; comparison with B. tryoni showed that the species are more closely related than any Drosophila species pair. The similarity of the genomes was exploited to identify 4924 potentially diagnostic indels between the species, all of which occur in non-coding regions.

Conclusions

This first draft B. tryoni genome resembles other dipteran genomes in terms of size and putative coding sequences. For all three species included in this study, we have identified a comprehensive set of non-redundant repetitive sequences, including the ribosomal RNA unit, and have quantified the major satellite DNA families. These genetic resources will facilitate the further investigations of genetic mechanisms responsible for the behavioural and morphological differences between these three species and other tephritids. We have also shown how whole genome sequence data can be used to generate simple diagnostic tests between very closely-related species where only one of the species is scaffolded.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1153) contains supplementary material, which is available to authorized users.