Matrix metalloproteinase-13 expression in rabbit knee joint connective tissues: influence of maturation and response to injury.

The hypothesis of the present work was that expression of matrix metalloproteinase-13 (MMP-13, collagenase-3) would be induced during conditions involving important matrix remodeling such as ligament maturation, scar healing and joint instability. Therefore, MMP-13 expression in the medial collateral ligament (MCL) during the variable situations of tissue maturation and healing was assessed. MMP-13 expression in three intra-articular connective tissues of the knee (i.e. articular cartilage, menisci and synovium) following the transection of the anterior cruciate ligament of the knee was evaluated at 3 and 8 weeks post-injury. MMP-13 mRNA (semi-quantitative RT-PCR) and protein (immunohistochemistry and Western blotting) were detected in all of the tissues studied. Significantly higher MCL mRNA levels for MMP-13 were detected during the early phases of tissue maturation (i.e. 29 days in utero and 2-month-old rabbits) compared to later phases (5- and 12-month-old rabbits). This pattern of expression was recapitulated following MCL injury, with very high levels of expression in scar tissue at 3 weeks post-injury and then a decline to levels not significantly different from control values by 14 weeks. Elevated mRNA levels correlated with increased protein levels for MMP-13 in both menisci and synovium following the transection of the anterior cruciate ligament and during medial collateral ligament healing. These results indicate that MMP-13 expression is regulated by a number of variables and that high levels of expression occur in situations when connective tissue remodeling is very active.     

Why does the hoverfly Metasyrphus corollae migrate?

Abstract. 1. Migration pattern and mass appearance of the hoverfly Metasyrphus corollae (F.) (Diptera, Syrphidae) were investigated on the SE coast of Sweden in 1981. In total, 4433 hoverflies, belonging to fifteen species, were collected in water traps during 4–6 August. All but 2.2% were M.corollae , 3282 specimens being caught on 4 August, 1021 on 5 August and thirty-five on 6 August.
2. The sex ratios ( ♂/♀ ) on these dates were 1/1.6, 1/1.3 and 1/1.7. The average dry weights did not significantly differ between sexes (males 4.01 mg, females 4.02 mg).
3. M.corollae females were reproductively immature.
4. Females mostly had Senecio pollen in their guts while males mainly had Rubus pollen. The average number of pollen grains per specimen was 210 for females and 1100 for males.
5. In the summer 1980 aphids were numerous, forming a basis for a high abundance of adult hoverflies (with hibernating larvae) in 1981. Aphid density in 1981 was low and stimuli inducing egglaying were sparse. It is suggested that this pattern of aphid abundance triggers migration in M.corollae and in other aphidophagous species at irregular intervals.     

Characterization of the natural immune response of rhesus monkey CD4+ve T cells to the bacterial antigen streptolysin O (SLO)

Abstract: Rhesus monkeys show a high proliferative T cell response to the bacterial exotoxin SLO without prior immunization. The present study was undertaken to characterize this naturally present SLO-responsiveness with particular emphasis on CD4^+ve reactive T cells. It is demonstrated that the frequency of SLO-reactive cells in the circulation ranges between 1 in 75 and 1 in 610 CD4^+ve T cells as determined with limiting dilution analysis. It is also shown that induction of a good proliferative response requires Mhc-DR matching between T cell and the antigen presenting cells (APC). Stable and DR-restricted SLO-specific CD4^+ve T cell lines were generated from CD8 depleted peripheral blood mononuclear cells (PBMC). The SLO-reactive CD4^+ve cell lines are tentatively characterized as Thl-like based on the predominant production of interferon-gamma (IFN-γ) over IL-4, although this seems contradicted by the IL-4 dependent growth of the lines.     

黄独微型块茎鲨烯合酶的基因克隆与序列分析

通过黄独微型块茎转录组数据库筛选到SQS基因的核心片段,利用RT-PCR技术获得SQS基因保守片段,采用RACE技术获得SQS基因的3′及5′末端序列,并采用生物信息学方法进行序列分析。结果表明,黄独微型块茎SQS基因编码序列长1548 bp,编码415 bp的氨基酸序列,理论分子量为46786.38 D,等电点(pI)为5.97。SQS蛋白为疏水性蛋白,无信号肽,含有SQS所必需的功能结构域,属于Isoprenoid_Biosym_C1 superfami?ly。黄独SQS蛋白与其他植物的SQS蛋白同源性较高,其中与盾叶薯蓣的SQS蛋白氨基酸相似性为96.4%。本试验结果从黄独微型块茎中首次获得SQS基因cDNA全长序列,该基因具有SQS同源基因的典型特征,为进一步研究黄独微型块茎SQS基因结构、基因表达和基因突变提供了基础,并为薯蓣属植物三萜合成通路关键酶SQS的正选择位点与功能的关联性分析提供了数据支持。     

Frequent mitochondrial gene introgression among high elevation Tibetan megophryid frogs revealed by conflicting gene genealogies

Historical mitochondrial introgression causes differences between a species' mitochondrial gene genealogy and its nuclear gene genealogy, making tree-based species delineation ambiguous. Using sequence data from one mitochondrial gene (cytochrome b ) and three nuclear genes (introns), we examined the evolutionary history of four high elevation Tibetan megophryid frog species, Scutiger boulengeri , Scutiger glandulatus , Scutiger mammatus and Scutiger tuberculatus . The three nuclear genes shared a similar history but the mitochondrial gene tree suggested a drastically different evolutionary scenario. The conflicts between them were explained by multiple episodes of mitochondrial introgression events via historical interspecific hybridization. 'Foreign' mitochondrial genomes might have been fixed in populations and extended through a large portion of the species' distribution. Some hybridization events were probably as old as 10 Myr, while others were recent. An F₁ hybrid was also identified. Historical hybridization events among the four species appeared to be persistent and were not restricted to the period of Pleistocene glaciation, as in several other well-studied cases. Furthermore, hybridization involved several species and occurred in multiple directions, and there was no indication of one mitochondrial genome being superior to others. In addition, incomplete lineage sorting resulting from budding speciation may have also explained some discrepancies between the mitochondrial DNA and nuclear gene trees. Combining all evidences, the former ' Scutiger mammatus ' appeared to be two species, including a new species. With the availability of a wide range of highly variable nuclear gene markers, we recommend using a combination of mitochondrial gene and multiple nuclear genes to reveal a complete species history.     

The paradoxes of failure in post-welfare: an auto-ethnography of caregiver labour for disabled persons in New York State

In conditions of post-welfare, failure takes a variety of forms. I offer an auto-ethnographic account of state-funded caregiving for people diagnosed with intellectual and developmental disabilities in New York State, where both caregiver labour and its management have been subjected to greater discipline as post-welfare initiatives seek to re-educate recipients of benefits and careworkers to be simultaneously more autonomous from and more accountable to the state. Placing these changes within the specific history of failed disability care in the United States, I explain how new disciplinary devices for reporting further alienate caregiver labour and complicate welfare management in practice.     

Sodium bioenergetics in methanogens and acetogens

Abstract Recent investigations with Methanosarcina barkeri elucidated the role of sodium ions in the energy metabolism of methanogenic bacteria and provided evidence for a novel mechanism of energy transduction with Na⁺ as the coupling ion. During methanogenesis from methanol, an eletrochemical sodium gradient generated by a Na⁺/H⁺ antiporter is used as the driving force for the thermodynamically unfavourable oxidation of methanol to the formal redox level of formaldehyde. During methanogenesis from H₂+ CO₂, the reverse reaction, the reduction of formaldehyde to the level of methanol, is accompanied by a primary, electron transport-driven sodium extrusion. Acetogenesis from H₂+ CO₂ as carried out by Acetobacterium woodii is a sodium-dependent process and is accompanied by the generation of a transmembrane sodium gradient with the reduction of formaldehyde to the level of methanol as the sodium-dependent step.     

A Taxonomic Study of European and East African Species of the Genera Pelecopsis and Trichopterna (Araneae, Linyphiidae), with Descriptions of a New Genus and Two New Species of Pelecopsis from Kenya

On the basis of the results of an analysis primarily of the morphology of the male palps and palpal organs the delimitation of the erigonine genera Pelecopsis Simon and Trichopterna Kulczyński and the phylogenetic relationships between European and East African species of these genera are discussed. For the East African species Pelecopsis convexa (Holm), and P. bacelarae (di Caporiacco), together with two undescribed species from Nigeria, the new genus Locketia is established. Pelecopsis humiliceps sp.n. and P. albifrons sp.n., both from Kenya, are described and P. tenera (Holm, 1962), preocc. P. tenera (Schenkel, 1927), is replaced by P. tenuipalpis nom.n. Viewpoints are presented on evolutionary trends and phylogeny of European and East African Pelecopsis species.