Diallyl trisulfide induces apoptosis and inhibits proliferation of A549 cells in vitro and in vivo

Lung cancer is the leading cause of cancer-related mortality all over the world. In recent years, pulmonary adenocarcinoma has surpassed squamous cell carcinoma in frequency and is the predominant form of lung cancer in many countries. Epidemiological investigations have shown an inverse relationship between garlic (Allium sativum) consumption and death rate from many cancers. Diallyl trisulfide (DATS) is one of the garlic-derived compounds (also known as: organosulfer compounds, OSC). DATS can induce apoptosis and inhibit the growth of many cancer cell lines. Our study demonstrated that the apoptotic incidents induced by DATS were a mitochondria-dependent caspase cascade through a significant decrease of the anti-apoptotic Bcl-2 that resulted in up-regulation of the ratio of Bax/Bcl-2 and the activity of caspase-3, -8, and -9. Eventually, DATS induced the apoptosis and inhibited the proliferation in a concentration- and time-dependent manner. Furthermore, by establishing an animal model of female BALB/c nude mice with A549 xenografts, we found that oral gavage of DATS significantly retarded growth of A549 xenografts in nude mice without causing weight loss or any other side effects compared with the control group. All the evidence both in vitro and in vivo suggested that DATS could be an ideal anti-cancer drug.     

A combined approach for improving alkaline acetyl xylan esterase production in Pichia pastoris, and effects of glycosylation on enzyme secretion, activity and stability

High level expression of axe1, a gene previously cloned from Volvariella volvacea that encodes an acetyl xylan esterase with two potential N-linked glycosylation sites, has been achieved in Pichia pastoris using a codon-optimized axe1 synthesized by the primer extension PCR procedure. The GC content of the codon-optimized axe1 was 48.62% compared with 55.49% in the native gene. Using the codon-optimized construct, AXE1 expression in P. pastoris was increased from an undetectable level to 136.45U/ml six days after induction of yeast cultures grown in BMMY medium. A further increase (to 463U/ml) was achieved when conditions for yeast culture were optimized as follows: 2.8% methanol, 0.63% casamino acids, and pH 8.0. This latter value represented a 3.4-fold and 246-fold increase in the enzyme levels recorded in non-optimized P. pastoris cultures and in rice straw-grown cultures of V. volvacea, respectively. N-linked glycosylation played an essential role in AXE1 secretion but had only a slight effect on the catalytic activity and stability of the recombinant enzyme.     

Tumor-specific idiotype vaccines. III. Induction of T helper cells by anti-idiotype and tumor cells

In a previous report, we have demonstrated the induction of tumor-specific immunity by monoclonal anti-idiotype antibodies generated against a monoclonal anti-tumor antibody, 11C1, that also cross-reacts with mouse mammary tumor virus envelope glycoprotein gp52. Also, we showed that whereas one anti-idiotype antibody, 2F10, could induce protective immunity, another anti-idiotype antibody, 3A4, induced nonprotective immunity. Here we demonstrated the existence of T helper cells which recognize anti-idiotypes that exert differential controls on tumor growth. The qualitative nature of idiotype recognizing T cells generated in response to 2F10, 3A4, irradiated tumor, and progressively growing tumor was compared. The reactivity pattern of idiotype recognizing T cells obtained from 2F10 and irradiated tumor immunized mice were similar in nature in the sense that Lyt-2- T cells obtained from these immunized mice responded to both 2F10 and 3A4 as antigen, although T cells from tumor immunized mice responded better to 3A4 antigen. On the other hand, the idiotype-recognizing T cells obtained from 3A4-immunized mice showed a similar reactivity pattern to T cells isolated from mice during the early phase of tumor growth (within day 4 to 5 after the inoculation of 10(4) live tumor cells). Lyt-2- T cells isolated from mice immunized with 3A4 or during the early phase of tumor growth responded only to 3A4 antigen. The inability of Lyt-2- T cells, isolated from 4- to 5-day-old tumor in mice, to cooperate with 2F10-TNP is not due to the absence of 2F10 idiotype recognizing T cells as 2F10 id recognizing T cells are present when examined at the precursor level. These data on the idiotype specificity of T helper cells show a correlation with the presence of anti-tumor immunity. This information will help in the design and application of idiotype vaccine in tumor immunotherapy.     

Biological Control of Carrot Black Rot

Diseased carrot seeds were treated with selected micro-organisms isolated from soils, carrot seeds and tap roots. The effects of those antagonists on the control of Alternaria radicina were evaluated by growing-on tests on water agar, filter paper, vermiculite and in a potting medium (BVB no. 4). The germination percentage, emergence percentage and the disease severity of those carrot seeds treated with Burkholderia (Pseudomonas) cepacia no.229 were significantly (P=0.05) differed from the non-treated seeds and the seed treated with other antagonists. The effects of B. cepacia no.229 in promoting seed emergence and controlling disease were as good as those seeds treated with iprodione (100 p.p.m.). Black rot lesions on carrot tap roots were significantly reduced (P=0.05) in size when roots were treated with B. cepacia no 229 or Bacillus amyloliquefaciens no. 224 compared to the nontreated roots. Also, B. cepacia no. 229 significantly (P=0.05) reduced black rot on the foliage of carrot compared to check.     

容积调控氯通道的研究进展

细胞在低渗环境中出现渗透性膨胀 ,随后细胞内的溶质及水分外流 ,使已膨胀的细胞容积向正常容积转化 ,此过程称为调节性细胞容积减小 (RVD) ,它是哺乳动物细胞普遍存在的现象。容积调控氯通道 (VRAC)在这个过程中起重要作用 ,不仅如此 ,最近研究发现VRAC参与了细胞增殖、分化和凋亡过程。本文主要综述了VRAC的生物学特点和生理功能等方面的研究进展     

Identification of salt-stress responsive genes in rice (Oryza sativa L.) by cDNA array

To identify salt stress-responsive genes, we constructed a cDNA library with the salttolerant rice cultivar, Lansheng. About 15000 plasmids were extracted and dotted on filters with Biomeck 2000 HDRT system or by hand. Thirty genes were identified to display altered expression levels responding to 150 mmol/L NaCl. Among them eighteen genes were up-regulated and the remainders downregulated. Twenty-seven genes have their homologous genes in GenBank Databases. The expression of twelve genes was studied by Northern analysis. Based on the functions, these genes can be classified into five categories, including photosynthesis-related gene, transportrelated gene, metabolismrelated gene, stress-or resistancerelated gene and the others with various functions. The results showed that salt stress influenced many aspects of rice growth. Some of these genes may play important roles in plant salt tolerance.     

Fe- and S-Metabolizing Microbial Communities Dominate an AMD-Contaminated River Ecosystem and Play Important Roles in Fe and S Cycling

Indigenous Fe- and S-metabolizing bacteria play important roles both in the formation and the natural attenuation of acid mine drainage (AMD). Due to its low pH and Fe-S-rich waters, a river located in the Dabaoshan Mine area provides an ideal opportunity to study indigenous Fe- and S-metabolizing microbial communities and their roles in biogeochemical Fe and S cycling. In this work, water and sediment samples were collected from the river for physicochemical, mineralogical, and microbiological analyses. Illumina MiSeq sequencing indicated higher species richness in the sediment than in the water. Sequencing also found that Fe- and S-metabolizing bacteria were the dominant microorganisms in the heavily and moderately contaminated areas. Fe- and S-metabolizing bacteria found in the water were aerobes or facultative anaerobes, including Acidithiobacillus, Acidiphilium, Thiomonas, Gallionella, and Leptospirillum. Fe- and S-metabolizing bacteria found in the sediment belong to microaerobes, facultative anaerobes, or obligatory anaerobes, including Acidithiobacillus, Sulfobacillus, Thiomonas, Gallionella, Geobacter, Geothrix, and Clostridium. Among the dominant genera in the sediment, Geobacter and Geothrix were rarely detected in AMD-contaminated natural environments. Canonical correspondence analysis indicated that pH, S, and Fe concentration gradients were the most important factors in structuring the river microbial community. Moreover, a scheme explaining the biogeochemical Fe and S cycling is advanced in light of the Fe and S species distribution and the identified Fe- and S-metabolizing bacteria.     

Oxidative stress induces autophagic cell death independent of apoptosis in transformed and cancer cells

Autophagy is a self-digestion process that degrades intracellular structures in response to stresses leading to cell survival. When autophagy is prolonged, this could lead to cell death. Generation of reactive oxygen species (ROS) through oxidative stress causes cell death. The role of autophagy in oxidative stress-induced cell death is unknown. In this study, we report that two ROS-generating agents, hydrogen peroxide (H(2)O(2)) and 2-methoxyestradiol (2-ME), induced autophagy in the transformed cell line HEK293 and the cancer cell lines U87 and HeLa. Blocking this autophagy response using inhibitor 3-methyladenine or small interfering RNAs against autophagy genes, beclin-1, atg-5 and atg-7 inhibited H(2)O(2) or 2-ME-induced cell death. H(2)O(2) and 2-ME also induced apoptosis but blocking apoptosis using the caspase inhibitor zVAD-fmk (benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone) failed to inhibit autophagy and cell death suggesting that autophagy-induced cell death occurred independent of apoptosis. Blocking ROS production induced by H(2)O(2) or 2-ME through overexpression of manganese-superoxide dismutase or using ROS scavenger 4,5-dihydroxy-1,3-benzene disulfonic acid-disodium salt decreased autophagy and cell death. Blocking autophagy did not affect H(2)O(2)- or 2-ME-induced ROS generation, suggesting that ROS generation occurs upstream of autophagy. In contrast, H(2)O(2) or 2-ME failed to significantly increase autophagy in mouse astrocytes. Taken together, ROS induced autophagic cell death in transformed and cancer cells but failed to induce autophagic cell death in non-transformed cells.