Preferential involvement of Tim-3 in the regulation of hepatic CD8+ T cells in murine acute graft-versus-host disease

Tim-3, a member of the T cell Ig mucin (TIM) family regulates effector Th1 responses. We examined Tim-3 and its ligand expression as well as the effects of anti-Tim-3 mAb treatment in a murine model of acute graft-vs-host disease (aGVHD). In mice with aGVHD, Tim-3 expression was markedly up-regulated on splenic and hepatic CD4+ and CD8+ T cells, dendritic cells (DCs), and macrophages, and this was especially dramatic in hepatic CD8+ T cells. Both donor- and host-derived CD8+ T cells induced similar levels of Tim-3. Tim-3 ligand expression was also up-regulated in splenic T cells, DCs, and macrophages, but not in the hepatic lymphocytes. The administration of anti-Tim-3 mAbs accelerated aGVHD, as demonstrated by body weight loss, reduction in total splenocyte number, and infiltration of lymphocytes in the liver. IFN-gamma expression by splenic and hepatic CD4+ and CD8+ T cells was significantly augmented by anti-Tim-3 mAb treatment. In addition, the cytotoxicity against host alloantigen by donor CD8+ T cells was enhanced. These results demonstrate that the anti-Tim-3 treatment in aGVHD augmented the activation of effector T cells expressing IFN-gamma or exerting cytotoxicity. Our results suggest that Tim-3 may play a crucial role in the regulation of CD8+ T cells responsible for the maintenance of hepatic homeostasis and tolerance.     

Coexpression of a defensin gene and a thionin-like gene via different signal transduction pathways in pepper and Colletotrichum gloeosporioides interactions

The anthracnose fungus, Colletotrichum gloeosporioides, interacts incompatibly with the ripe fruit of pepper (Capsicum annuum). It interacts compatibly with the unripe-mature fruit. We isolated a defensin gene, j1-1, and a thionin-like gene, PepThi, expressed in the incompatible interaction by using an mRNA differential display method. Both genes were developmentally regulated during fruit ripening, organ-specifically regulated, and differentially induced during the compatible and incompatible interactions. Expression of the PepThi gene was rapidly induced in the incompatible-ripe fruit upon fungal infection. The fungus-inducible PepThi gene is highly inducible only in the unripe fruit by salicylic acid. In both ripe and unripe fruit, it was induced by wounding, but not by jasmonic acid. Expression of the j1-1 gene is enhanced by jasmonic acid in the unripe fruit but suppressed in the ripe fruit. These results suggest that both small and cysteine-rich protein genes are induced via different signal transduction pathways during fruit ripening to protect the reproductive organs against biotic and abiotic stresses.     

中国茜草科资料之二

在编研《中国植物志》茜草科的过程中,对龙船花属（Ｉｘｏｒａ）植物作进一步检查和整理,共发现６个新分类群Ｉｘｏｒａｉｎｓｉｇｎｉｓ,Ｉ．ａｍｐｌｅｘｉｃａｕｌｉｓ,Ｉ．ａｕｒｉｃｕｌａｒｉｓ,Ｉ．ｐａｒａｏｐａｒａ,Ｉ．ｆｏｎｃｈｅｗｉ,Ｉ．ｇｒａｃｉｌｉｓ;新种的模式标本保存在中国科学院华南植物研究所标本馆（ＩＢＳＣ）。     

Stable expression of a fungal laccase protein using transplastomic tobacco

Laccase catalyzes the oxidation of various phenolic compounds that can be used in a wide range of industrial applications such as waste detoxification and the textile industry. In the present study, we generated transplastomic tobacco plants to develop a reliable commercial source of laccase production. The stability of the laccase protein in the transgenic plants was increased by using the enhancer sequence from green fluorescent protein, resulting in three independent lines with high levels of laccase accumulation (up to 2?% of total protein); significant laccase activity, however, was not detected. Interestingly, the transplastomic lines showed slightly retarded vegetative growth, with a light green leaf color in comparison with the control, which may be attributable to copper deficiency induced by ligand chelation by abundantly produced laccase. These results suggest that the tobacco chloroplast is an efficient system for the mass production of laccase protein, but further studies are needed to obtain active enzyme.     

Tissue and concentration-dependent effects of sodium selenite on muscle contraction

In this study, we demonstrated that sodium selenite with high doses (≥ 10^-3 M) were potent in inducing a contracture type effect on heart and smooth muscles. Selenite (Se), at a concentration of 10^-3 M, caused a contracture effect in heart preparations. Also, low Se concentrations did not have any significant effect. Although low concentrations of Se (≥ 10^-5 M) had a biphasic effects on acetylcholine (ACh) induced and spontaneous ileum contractions, 10^-3 M selenite enhanced once more a contracture effect similar to that of the heart preparations. Replacing Ca²⁺ concentration of the bathing solution by twofold Ca²⁺ or Ca²⁺-free did not change the effects of selenite (10^-5 M) on contractility of ileum preparations. In vascular smooth muscle, low concentration of selenite (<10^-4) had no significant effects on KC1, and phenylephrine-induced contractions and acethylcholineinduced endothelium-dependent relaxations of isolated rabbit aorta. However, the contractions induced by phenylephrine and the relaxations induced by acetylcholine in rabbit aorta were depressed significantly by high concentration of selenite (10^-3 M). The results obtained by selenite exposure from these three different types of tissue preparations first suggest that the high concentration of selenite exposure induces some alterations in the functions of muscles and endothelium in a tissue and dose-dependent manner. Second, this observed irreversible type of dysfunction of tissues induced by l0^-3 M selenite is not directly dependent on the Ca²⁺ entrance into the cytosol, but might be induced by the increase of intracellular Ca²⁺ with the disturbance of Ca²⁺ regulation.     

Effects of epidural administration of xylazine or lidocaine on bovine uterine motility and perineal analgesia

The objective of this study was to evaluate and compare the effects of caudal epidural (sacral-coccygeal interspace) administration of xylazine or lidocaine on uterine motility and perineal analgesia in the cow. Six Holstein cows (7 d post estrus) were assigned to one of three treatment groups: control (5 ml saline); lidocaine (0.2 mg/kg, 2% solution); and xylazine (0.06 mg/kg suspended in 5 ml saline), with each cow randomly assigned to each treatment over a period of three estrous cycles. Uterine motility, perineal analgesia, electrocardiography, and overt signs of sedation were recorded. Data were collected at 10-min intervals starting 10 min before treatment and continuing until 60 min post treatment. At 60 min post treatment, oxytocin (20 USP units) was administered i.v. to serve as a positive control for uterine motility. In the xylazine group, uterine motility significantly (P < 0.05) increased at 20 min post treatment, peaked at 30 min, and gradually decreased to non-significant levels at 50 min post treatment when compared with the lidocaine and control groups. Additionally, xylazine produced a higher degree and longer duration of perineal analgesia than lidocaine. Systemically, epidural xylazine produced signs of sedation, salivation, vocalization and bradycardia. Ataxia was also observed in the xylazine-treated group which may have been induced through a local and/or systemic effect. The individual properties of xylazine and lidocaine should be taken into consideration when performing an obstetrical procedure requiring the use of an epidural analgesic agent, and they should be utilized to benefit the clinician in performing the procedure.     

Methylene blue alleviates nuclear and mitochondrial abnormalities in progeria

Hutchinson–Gilford progeria syndrome (HGPS), a fatal premature aging disease, is caused by a single‐nucleotide mutation in the LMNA gene. Previous reports have focused on nuclear phenotypes in HGPS cells, yet the potential contribution of the mitochondria, a key player in normal aging, remains unclear. Using high‐resolution microscopy analysis, we demonstrated a significantly increased fraction of swollen and fragmented mitochondria and a marked reduction in mitochondrial mobility in HGPS fibroblast cells. Notably, the expression of PGC‐1α, a central regulator of mitochondrial biogenesis, was inhibited by progerin. To rescue mitochondrial defects, we treated HGPS cells with a mitochondrial‐targeting antioxidant methylene blue (MB). Our analysis indicated that MB treatment not only alleviated the mitochondrial defects but also rescued the hallmark nuclear abnormalities in HGPS cells. Additional analysis suggested that MB treatment released progerin from the nuclear membrane, rescued perinuclear heterochromatin loss and corrected misregulated gene expression in HGPS cells. Together, these results demonstrate a role of mitochondrial dysfunction in developing the premature aging phenotypes in HGPS cells and suggest MB as a promising therapeutic approach for HGPS.     

Preparation of an active recombinant peptide of crustacean androgenic gland hormone

In crustaceans, male sexual characteristics are induced by a hormone referred to as androgenic gland hormone. We have recently cloned a candidate cDNA in the terrestrial isopod Armadillidium vulgare. In order to prove that this cDNA encodes the hormone, recombinant single-chain precursor molecules consisting of B chain, C peptide and A chain were produced using both baculovirus and bacterial expression systems. Neither recombinant precursors showed activity. Digestion of only the precursor carrying a glycan moiety with lysyl endopeptidase gave a heterodimeric peptide with hormonal activity by removing a part of C peptide. These results indicate that the cDNA encodes the hormone.