Immune regulation of bone loss by Th17 cells

A significant macrophage and T-cell infiltrate commonly occurs in inflammatory joint conditions such as rheumatoid arthritis that have significant bone destruction. Cytokines produced by activated macrophages and T cells are implicated in arthritis pathogenesis and are involved in osteoclast-mediated bone resorption. The scope of the present review is to analyze current knowledge and to provide a better understanding of how macrophage-derived factors promote the differentiation of a novel T-helper subset (Th17) that promotes osteoclast formation and activation.     

Subcellular localization of EGFR in esophageal carcinoma cell lines

Background: The EGF receptor is a therapeutic target in cancer cells, whereby mutations of EGFR and/or signalling members act as predictive markers. EGFR however also exhibits dynamic changes of subcellular localization, leading to STAT5 complex formation, nuclear translocation and induction of Aurora-A expression in squamous cancer cells. We previously described high EGFR and Aurora-A expression in esophageal cancer cells. Here, we investigated subcellular localization of EGFR and STAT5 in esophageal cancer cells. Results: Quantitative immunofluorescence analyses of four esophageal cancer cell lines reflecting esophageal squamous cell carcinomas (ESCC) and esophageal adenocarcinomas (EAC) revealed that the subcellular localization of EGFR was shifted from a membranous to cytoplasmic localization upon EGF-stimulation in OE21 (ESCC) cells. Thereby, EGFR in part co-localized with E-Cadherin. In parallel, phosphorylated STAT5-Tyr694 appeared to increase in the nucleus and to decrease at the cell membrane. In three additional cell lines, EGFR was only marginally (Kyse-410/ESCC; OE19/EAC) and weakly (OE33, EAC) detectable at the cell membrane. Partial co-localization of EGFR and E-Cadherin occurred in OE33 cells. Post EGF-stimulation, EGFR was detected in the cytoplasm, resembling endosomal compartments. Furthermore, OE19 and OE33 exhibited nuclear STAT5-Tyr694 phosphorylation upon EGF-stimulation. None of the four cell lines showed nuclear EGFR expression and localization. Conclusion: In contrast to other (squamous) cancer cells, activation of EGFR in esophageal squamous cancer cells does not result in nuclear translocation of EGFR. Still, the subcellular localization of EGFR may influence STAT5-associated signaling pathways in esophageal cancer cells and hence possibly also the responses to ErbB, respective EGFR-targeted therapies.     

Enzymatic Dehalogenation of Pentachlorophenol by <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> of the Microbial Community from Tannery Effluent

Four different bacterial isolates obtained from a stable bacterial consortium were capable of utilizing pentachlorophenol (PCP) as sole carbon and energy source. The consortium was developed by continuous enrichment in the chemostat. The degradation of PCP by bacterial strain was preceded through an oxidative route as indicated by accumulation of tetrachloro-ρ-hydroquinone and dichlorohydroquinone as determined by high performance liquid chromatography (HPLC). Among the four isolates, Pseudomonas fluorescens exhibited maximum degradation capability and enzyme production. PCP-monooxygenase enzyme was extracted from culture extract and fractionated by DEAE-cellulose ion exchange chromatography. The molecular weight of the enzyme, purified from Pseudomonas fluorescens, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography was found to be 24,000 Da. Received: 22 July 2002 / Accepted: 23 September 2002     

Multi-Stability and Multi-Instability Phenomena in a Mathematical Model of Tumor-Immune-Virus Interactions

Recent advances in virology, gene therapy, and molecular and cell biology have provided insight into the mechanisms through which viruses can boost the anti-tumor immune response, or can infect and directly kill tumor cells. A recent experimental report (Bridle et al. in Molec. Ther. 18(8):1430–1439, 2010) showed that a sequential treatment approach that involves two viruses that carry the same tumor antigen leads to an improved anti-tumor response compared to the effect of each virus alone. In this article, we derive a mathematical model to investigate the anti-tumor effect of two viruses, and their interactions with the immune cells. We discuss the conditions necessary for permanent tumor elimination and, in this context, we stress the importance of investigating the long-term effect of non-linear interactions. In particular, we discuss multi-stability and multi-instability, two complex phenomena that can cause abrupt transitions between different states in biological and physical systems. In the context of cancer immunotherapies, the transitions between a tumor-free and a tumor-present state have so far been associated with the multi-stability phenomenon. Here, we show that multi-instability can also cause the system to switch from one state to the other. In addition, we show that the multi-stability is driven by the immune response, while the multi-instability is driven by the presence of the virus.     

长时程增强诱导和维持过程中海马CA1区神经细胞粘附分子蛋白水平与mRNA表达的变化

既往研究发现,神经细胞粘附分子(neural cell adhesion molecules,NCAM)对海马CA1区突触传递长时程增强(longterm potentiation,LTP)的诱导和维持极为关键。本文采用原位杂交法和Western blot法,观察了大鼠海马腑片LTP诱导和维持过程中NCAM mRNA和蛋白水平的动态变化过程。结果显示,强直刺激诱发fEPSP斜率升高10 min时,海马CA1区NCAM mRNA染色阳性神经元数量显著增加(76.6±11.5个),NCAM蛋白水平亦明显升高(7.190±0.64任意单位/50μg蛋白)。强直刺激诱发fEPSP斜率升高1 h时,NCAM mRNA染色阳性神经元数量为73.3±14.0个,NCAM蛋白量为9.031±0.71任意单位/50 μg蛋白;与强直刺激后10 min比较,NCAM mRNA表达无显著变化,而NCAM蛋白水平变化明显。NMDA受体特异阻断剂AP-5在损害LTP的同时,显著抑制NCAM mRNA和蛋白的增加。实验结果表明,在大鼠海马LTP诱导和维持过程中,NCAM mRNA增强的表达相对稳定,而NCAM蛋白水平呈现先低后高的变化。     

Associations between primates and other mammals in a central Amazonian forest landscape

Little information exists on mixed-species groups between primates and other mammals in Neotropical forests. In this paper, we describe three such associations observed during an extensive large-vertebrate survey in central Amazonia, Brazil. Mixed-species groups between a primate species and another mammal were observed on seven occasions between squirrel monkeys (Saimiri cf. ustus) and either South American coatis (Nasua nasua) or tayras (Eira barbara) and between brown capuchins (Cebus apella) and coatis. All associations were restricted to floodplain forest during its dry stage. We suggest that the associations involving the coatis are connected to foraging and vigilance but may be induced by a common alternative food resource at a time of food shortage.     

入侵杂草化感作用的细胞自动机模拟研究

细胞自动机模型(Cellular Automata Model,简称CA模型)是一种能够表现系统复杂行为的模拟方法,适于研究植物群落时空动态过程.本文利用CA模型,模拟具有化感作用的外来种入侵原有物种所构成植被的过程.模型由产生化感物质的外来种和两个对化感物质敏感性不同的本地种组合成不同类型的群落,利用化感物质作用下受体物种生物活性响应模型及种子扩散负指数分布模型,模拟外来杂草和本地种分布格局的时空动态变化.结果表明,外来种可成功地完全入侵由两个对化感物质敏感的本地种构成的群落空间,但对于由对化感物质敏感的一个本地种及对化感物质具有抗性的另一个本地种构成的群落,外来种只能够与本地种共存.     

The chimeric cytokine Hyper-IL-6 enhances the efficiency of lentiviral gene transfer in hepatocytes both in vitro and in vivo

Lentiviral vectors have been used for gene transfer into the liver but their ability to efficiently transduce quiescent hepatocytes remains controversial. Lentivirus-mediated gene transfer is more efficient in cycling cells. We determine the effect of H-IL6 in the lentiviral transduction. The lentiviral vector was used to transduce HepG2 cells and mice liver cells, previously treated with H-IL6. The highest transduction level was observed in HepG2 cells treated with 30 ng/mL H-IL6 and in the mice that received 4 μg H-IL6. Our results suggest that H-IL6 is an inducer of lentiviral gene transfer into the liver cells without any toxicity.     

Sortase-mediated protein ligation: an emerging biotechnology tool for protein modification and immobilisation

Sortases are transpeptidases produced by Gram-positive bacteria to anchor cell surface proteins covalently to the cell wall. The Staphylococcus aureus sortase A (SrtA) cleaves a short C-terminal recognition motif (LPXTG) on the target protein followed by the formation of an amide bond with the pentaglycine cross-bridge in the cell wall. Over recent years, several researchers have exploited this specific reaction for a range of biotechnology applications, including the incorporation of non-native peptides and non-peptidic molecules into proteins, the generation of nucleic acid–peptide conjugates and neoglycoconjugates, protein circularisation, and labelling of cell surface proteins on living cells.     

The effect of jasmonic acid on the accumulation of ABA,proline and spermidine and its influence on membrane injury under water deficit in two barley genotypes

Seedlings of two barley genotypes (‘Maresi’ and wild form of Hordeum spontaneum) were treated with jasmonic acid (JA 5 μM and 15 μM) for 24 h, and then subjected to water stress (PEG 6000 solution of − 1.5 MPa). JA caused an increase in the content of ABA but not in that of proline and spermidine in the two studied genotypes. The effect of the treatment did not depend on the applied JA concentration. The pre-stress treatment with JA changed plant response to water deficit with regard to membrane injury. Treatment with a lower JA concentration (5 μM) caused a substantial reduction of the stress-induced membrane damage in the both genotypes. A higher JA concentration (15 μM) caused the reduction of membrane injury only in H. spontaneum and was ineffective in ‘Maresi’. JA had no influence on the leaf water status in water-stressed plants. A possible role of JA in leaf ABA accumulation and alleviation of cell membrane injury under water deficit is discussed. The work was partly supported by the Polish Committee For Scientific Research, grant No 5 PO6A 036 18