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Summary Intercellular junctions in the uterine epithelium of the ovoviviparous urodele Salamandra salamandra were studied in pregnant and non-pregnant females by freeze-fracture technique. Junctional complexes consist of zonulae occludentes (tight junctions) and numerous maculae adhaerentes (desmosomes); z. adhaerentes and nexuses (gap junctions) could not be identified. Tight junctions are of the flexible type exhibiting loosely interconnected fibrils. The fibrillary network appears stretched more often in pregnant females possibly due to the mechanical stress of pregnancy. The structure and occurrence of the junctions identified, especially that of the tight junctions, is discussed with regard to the functions of the uterus during pregnancy.Zusammenfassung Mit Hilfe der Gefrierbruchtechnik wurden im Uterus-epithel trächtiger und nichtträchtiger Feuersalamanderweibchen (Salamandra salamandra) Zonulae occludentes und Maculae adhaerentes, jedoch keine Z. adhaerentes sowie Nexus identifiziert. Die Z. occludentes sind flexibel. Ihr fibrilläres Netzwerk ist bei trächtigen Weibchen öfter gestreckt; das ist möglicherweise auf die stärkere Ausdehnung des Uterusgewebes während der Trächtigkeit zurückzuführen. Das Vorkommen der verschiedenen Kontakt-strukturen, namentlich das der Z. occludentes, wird im Hinblick auf die Funktionen des Uterus während der Trächtigkeit diskutiert.We are indebted to Mrs. K. Ott for excellent technical assistance and to Miss Dr. U. Beigel for linguistic help 相似文献
3.
Summary Results of investigations on the occurrence of nerve fibres and endings in the synovial membrane of the knee and elbow joint in the cat are reported. The stratum synoviale contains only autonomic fibres, running in the adventitia of arteries.Free nerve endings are lacking in the stratum synoviale. Simple Pacinian corpuscles with an inner core are occasionally observed in the border zone between the stratum synoviale and fibrosum. The ultrastructure of these endorgans resembles that of Pacinian corpuscles in the hairless and hairy skin of the cat. 相似文献
4.
Günter Müller PD Dr. 《当今生物学》2010,40(1):46-54
Typical civilization diseases, such as type II diabetes, are common, complex in the underlying pathogenic mechanisms, heterogenous in the phenotype and multifactorial due to a wide variety of possible combinations of disease susceptibility or protective genes in different relevant tissues and negative or positive environmental factors. This is in sharp contrast to classical inherited diseases, such as Chorea Huntington, which are often caused by complete loss‐ or gain‐of‐function mutations in a single gene. The causative polymorphisms of susceptibility genes, however, are characterized by relative subtle alterations in the function of the corresponding gene product, which per se do not support the pathogenesis, by high frequency, high expenditure for their identification and rather low predictive value. Consequently, the reliable and early diagnosis of civilization diseases depends on the individual determination of all (or as many as possible) polymorphisms of each susceptibility gene together with the corresponding gene products and the metabolites emerging thereof. 相似文献
5.
Summary The microproblematicumPycnoporidium ? eomesozoicum
Flügel, 1972, from Upper Triassic reefs of the Alpine-Mediterranean region, Turkey Oman and Iran (originally interpreted as possible
alga) represents the type species of a new strophomenid brachiopod genus (Gosaukammerella n.g.). The genus is characterized by a very small, millimeter-sized plano-convex shell, whose ventral valve is attached to
the substratum (mainly sponges) by symmetrically arranged outgrowths developing from a pseudopunctate, lamellose foliated
shell wall and composed of densely spaced subparallel ‘tubes’ comparable with productide spines secreted by papillose extensions
of the mantle.Gosaukammerella seems to be the only reliable candidate for the existence of post-Paleozoic strophomenid (productid ?) brachiopods.
Gosaukammerella eomesozoica is restricted to possibly cryptic, shaded reef environments inhabited predominantly by sponges serving as substrates for
micromorphic brachiopods. 相似文献
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7.
Varsha A. Potdar Mandeep S. Chadha Santosh M. Jadhav Jayati Mullick Sarah S. Cherian Akhilesh C. Mishra 《PloS one》2010,5(3)
Background
The Influenza A pandemic H1N1 2009 (H1N1pdm) virus appeared in India in May 2009 and thereafter outbreaks with considerable morbidity and mortality have been reported from many parts of the country. Continuous monitoring of the genetic makeup of the virus is essential to understand its evolution within the country in relation to global diversification and to track the mutations that may affect the behavior of the virus.Methods
H1N1pdm viruses were isolated from both recovered and fatal cases representing major cities and sequenced. Phylogenetic analyses of six concatenated whole genomes and the hemagglutinin (HA) gene of seven more isolates from May-September 2009 was performed with reference to 685 whole genomes of global isolates available as of November 24, 2009. Molecular characterization of all the 8 segments was carried out for known pathogenic markers.Results
The first isolate of May 2009 belonged to clade 5. Although clade 7 was the dominant H1N1pdm lineage in India, both clades 6 and 7 were found to be co-circulating. The neuraminidase of all the Indian isolates possessed H275, the marker for sensitivity to the neuraminidase inhibitor Oseltamivir. Some of the mutations in HA are at or in the vicinity of antigenic sites and may therefore be of possible antigenic significance. Among these a D222G mutation in the HA receptor binding domain was found in two of the eight Indian isolates obtained from fatal cases.Conclusions
The majority of the 13 Indian isolates grouped in the globally most widely circulating H1N1pdm clade 7. Further, correlations of the mutations specific to clade 7 Indian isolates to viral fitness and adaptability in the country remains to be understood. The D222G mutation in HA from isolates of fatal cases needs to be studied for pathogenicity. 相似文献8.
PD Dr. G. F. Jirikowski J. F. Ramalho-Ortigao K. W. Kesse F. E. Bloom 《Histochemistry and cell biology》1990,94(2):187-190
Summary We recently described a nonradioactive method for in situ hybridization with 5-bromo-2-deoxyuridine (BrdU) labelled oligonucleotide
probes. An antibody to BrdU and immunocytochemistry were used in order to detect the hybridization signal. We have now applied
this method to semithin Epon sections, in order to hybridize consecutive sections through single cells with different probes
and to stain them with antibodies to neuropeptides. It could be shown that Epon embedding preserves mRNA well. In the present
study we used a BrdU labelled synthetic oligonucleotide probe complementary to a fragment of the vasopressin precursor and
an antibody to Arg-vasopressin. Vasopressin mRNA was demonstrable in a fraction of the vasopressin immunoreactive neurons
in the magnocellular nuclei. In addition some of the magnocellular neurons showed either hybridization or vasopressin immunostaining
only, perhaps indicating different stages of synthetic and secretory activity.
The method described seems to be a valuable tool for studying synthetic activity in peptidergic neurons on a single cell level.
The method might also have potential for in situ hybridization on the electronmicroscopical level. 相似文献
9.
Irene Pichler Fabiola Del Greco M. Martin G?gele Christina M. Lill Lars Bertram Chuong B. Do Nicholas Eriksson Tatiana Foroud Richard H. Myers PD GWAS Consortium Michael Nalls Margaux F. Keller International Parkinson's Disease Genomics Consortium Wellcome Trust Case Control Consortium Beben Benyamin John B. Whitfield Genetics of Iron Status Consortium Peter P. Pramstaller Andrew A. Hicks John R. Thompson Cosetta Minelli 《PLoS medicine》2013,10(6)
Background
Although levels of iron are known to be increased in the brains of patients with Parkinson disease (PD), epidemiological evidence on a possible effect of iron blood levels on PD risk is inconclusive, with effects reported in opposite directions. Epidemiological studies suffer from problems of confounding and reverse causation, and mendelian randomization (MR) represents an alternative approach to provide unconfounded estimates of the effects of biomarkers on disease. We performed a MR study where genes known to modify iron levels were used as instruments to estimate the effect of iron on PD risk, based on estimates of the genetic effects on both iron and PD obtained from the largest sample meta-analyzed to date.Methods and Findings
We used as instrumental variables three genetic variants influencing iron levels, HFE rs1800562, HFE rs1799945, and TMPRSS6 rs855791. Estimates of their effect on serum iron were based on a recent genome-wide meta-analysis of 21,567 individuals, while estimates of their effect on PD risk were obtained through meta-analysis of genome-wide and candidate gene studies with 20,809 PD cases and 88,892 controls. Separate MR estimates of the effect of iron on PD were obtained for each variant and pooled by meta-analysis. We investigated heterogeneity across the three estimates as an indication of possible pleiotropy and found no evidence of it. The combined MR estimate showed a statistically significant protective effect of iron, with a relative risk reduction for PD of 3% (95% CI 1%–6%; p = 0.001) per 10 µg/dl increase in serum iron.Conclusions
Our study suggests that increased iron levels are causally associated with a decreased risk of developing PD. Further studies are needed to understand the pathophysiological mechanism of action of serum iron on PD risk before recommendations can be made. Please see later in the article for the Editors'' Summary 相似文献10.
PD Dr. Stefan Pelzer 《当今生物学》2012,42(2):98-106
Tailor‐made microorganisms Microbial diversity provides unlimited resources for the development of novel industrial processes and products. Since the beginning of the 20th century microorganisms have been successfully applied for the large scale production of bio‐based products. In recent years, modern methods of strain development and Synthetic Biology have enabled biotech engineers to design even more sophisticated and tailor‐made microorganisms. These microbes serve industrial processes for the production of bulk chemicals, enzymes, polymers, biofuels as well as plant‐derived ingredients such as Artemisinin in an ecologically and economically sustainable and attractive fashion. In the future, production of advanced biofuels, microbial fuel cells, CO2 as feedstock and microbial cellulose are research topics as well as challenges of global importance. Continuous efforts in microbiology and biotechnology research will be pivotal for white biotechnology to gain more momentum in transforming the chemical industry towards a knowledge based bio‐economy. 相似文献