A ginger derivative,zingerone—a phenolic compound—induces ROS‐mediated apoptosis in colon cancer cells (HCT‐116)

Zingerone (ZO), an active phenolic agent derived from Zingiber officinale (Ginger), has many pharmacological properties such as antioxidant, antiangiogenic, and antitumor. However, its potential value in cancer and the mechanism by which ZO wields its therapeutic effects remain obscure. Therefore, in this current study, we explored the effects of ZO on suppressing cell proliferation and enhancing apoptosis in colon cancer cells (HCT116). Our results indicated that ZO significantly enhances the production of reactive oxygen species, lipid peroxidation (thiobarbituric acid reactive substance [TBARS]), and loss of cell viability; and reduces mitochondrial membrane potential and antioxidant levels (SOD, CAT, and GSH) in ZO‐treated HCT116 cells in a dose‐dependent (2.5, 5, and 10 µM) manner. Furthermore, ZO induces oxidative stress‐mediated apoptosis as evidenced by apoptotic morphological changes predicted by AO/EtBr, Hoechst staining and further confirmed by comet assay. Moreover, immunoblotting techniques showed that ZO treatment effectively enhances Bax, caspase‐9, and caspase‐3 expressions and decreases the expression of Bcl‐2 in colon cancer cells. Together, our results evidenced that the antitumor effects of ZO reduce cell proliferation and stimulate apoptosis through modulating pro‐ and antiapoptotic molecular events in HCT116 colon cancer cells. Therefore, based on our findings, ZO may be used as a therapeutic agent for the treatment of colon cancer.     

Mycobacterium senegalense from bovines in Eastern Nigeria

M ohan , K. 1985. Mycobacterium senegalense from bovines in Eastern Nigeria. Journal of Applied Bacteriology 59 , 277–281.
Detailed characteristics of three mycobacterial strains sharing important properties of Mycobacterium senegalense are described. Their physiological properties were compared with those of a typical M. senegalense strain described by Chamoiseau (1979), six strains of M. senegalense and one typical strain of M. fortuitum from the culture collection of Institute of Microbiology, Rutgers. The three Nigerian strains exhibited minor variations in their physiological properties when compared with other strains of M. senegalense . Unlike the strain of Chamoiseau the Nigerian strains did not utilize benzoate or citrate. The strains were also different from the other six strains of M. senegalense by utilizing trehalose and in failing to produce acid in mannitol. Unlike earlier isolates of M. senegalense the Nigerian strains were not from cases of bovine farcy but from cases with pathological manifestations of pulmonary tuberculosis. They appeared to be intermediate strains between M. senegalense and M. fortuitum . These results raise doubts on the justification for giving specific rank to M. senegalense .     

Molecular cloning and characterization of the mouse UDP-N-acetylglucosamine:α-3- -mannoside β-1,2-N-acetylglucosaminyltransferase I gene

The biosynthesis of protein-bound complex N-glycans in mammals requires a series of covalent modifications governed by a large number of specific glycosyltransferases and glycosidases. The addition of oligosaccharide to an asparagine residue on a nascent polypeptide chain begins in the endoplasmic reticulum. Oligosaccharide processing continues in the Golgi apparatus to produce a diversity of glycan structures. UDP-N-acetylglucosamine:α-3- -mannoside β-1,2-N-acetylglucosaminyltransferase I (EC 2.4.1.101; GlcNAc-TI) is a key enzyme in the process because it is essential for the conversion of high-mannose N-glycans to complex and hybrid N-glycans. We have isolated the mouse gene encoding GlcNAc-TI (Mgat-1) from a genomic DNA library. The mouse sequence is highly conserved with respect to the human and rabbit homologs and exists as a single protein-encoding exon. Mgat-1 was mapped to mouse Chromosome 11, closely linked to the gene encoding interleukin-3 by the analysis of multilocus interspecies backcrosses. RNA analyses of Mgat-1 expression levels revealed significant variation among normal tissues and cells.     

Structural perturbation of α-crystallin and its chaperone-like activity

α-Crystallin is a multimeric lenticular protein that has recently been shown to be expressed in several non-lenticular tissues as well. It is shown to prevent aggregation of non-native proteins as a molecular chaperone. By using a non-thermal aggregation model, we could show that this process is temperature-dependent. We investigated the chaperone-like activity of α-crystallin towards photo-induced aggregation of γ-crystallin, aggregation of insulin and on the refolding induced aggregation of β- and γ-crystallins. We observed that α-crystallin could prevent photo-aggregation of γ-crystallin and this chaperone-like activity of α-crystallin is enhanced several fold at temperatures above 30°C. This enhancement parallels the exposure of its hydrophobic surfaces as a function of temperature, probed using hydrophobic fluorescent probes such as pyrene and 8-anilinonaphthalene-1-sulfonate. We, therefore, concluded that α-crystallin prevents the aggregation of other proteins by providing appropriately placed hydrophobic surfaces; a structural transition above 30°C involving enhanced or re-organized hydrophobic surfaces of α-crystallin is important for its chaperone-like activity. We also addressed the issue of conformational aspects of target proteins and found that their aggregation prone molten globule states bind to α-crystallin. We trace these developments and discuss some new lines that suggest the role of tertiary structural aspects in the chaperone process.     

N‐acetylcysteine counteracts oxidative stress and prevents hCG‐induced apoptosis in rat Leydig cells through down regulation of caspase‐8 and JNK

We have earlier reported that following persistent stimulation with hCG, oxidative stress‐induced apoptosis in rat Leydig cells was mainly achieved through the extrinsic pathway. In the present study, the role of N‐acetylcysteine (NAC) in counteracting the oxidative stress and the mechanisms of inhibition of apoptosis under such conditions were investigated. NAC (1 mM) intervention with repeated hCG stimulation (50 ng/ml, four times, each with 30 min challenge) prevented the decline in Leydig cell viability and the rise in lipid peroxidation and reactive oxygen species. Simultaneously, the activities of the enzymes glutathione‐S‐transferase, catalase, superoxide dismutase and the intracellular glutathione and antioxidant capacity of the treated cells improved significantly. Apoptotic markers Fas, FasL, and caspase‐8, up‐regulated following repeated hCG exposure, were significantly down‐regulated following NAC co‐incubation. While Bcl‐2 expression was fully restored, Bax and caspase‐9 remained unchanged. NAC treatment induced down‐regulation of upstream JNK/pJNK and down‐stream caspase‐3 in the target cells. Taken together, the above findings indicate that NAC counteracted the oxidative stress in Leydig cells induced as a result of repeated hCG stimulation, and inhibited apoptosis by mainly regulating the extrinsic and JNK pathways of metazoan apoptosis. Mol. Reprod. Dev. 77:900–909, 2010. © 2010 Wiley‐Liss, Inc.     

Hepatic HMOX1 Expression Positively Correlates with Bach-1 and miR-122 in Patients with HCV Mono and HIV/HCV Coinfection

Aim

To analyze the expression of HMOX1 and miR-122 in liver biopsy samples obtained from HCV mono-and HIV/HCV co-infected patients in relation to selected clinical parameters, histological examination and IL-28B polymorphism as well as to determine whether HMOX1 expression is dependent on Bach-1.

Materials and Methods

The study group consisted of 90 patients with CHC: 69 with HCV mono and 21 with HIV/HCV co-infection. RT-PCR was used in the analysis of HMOX1, Bach-1 and miR-122 expression in liver biopsy samples and in the assessment of IL-28B single-nucleotide polymorphism C/T (rs12979860) in the blood. Moreover in liver biopsy samples an analysis of HO-1 and Bach-1 protein level by Western Blot was performed.

Results

HCV mono-infected patients, with lower grading score (G<2) and higher HCV viral load (>600000 IU/mL) demonstrated higher expression of HMOX1. In patients with HIV/HCV co-infection, the expression of HMOX1 was lower in patients with lower lymphocyte CD4 count and higher HIV viral load. IL28B polymorphism did not affect the expression of either HMOX1 or miR-122. Higher HMOX1 expression correlated with higher expression of Bach-1 (Spearman’s ρ = 0.586, p = 0.000001) and miR-122 (Spearman’s ρ = 0.270, p = 0.014059).

Conclusions

HMOX1 and miR-122 play an important role in the pathogenesis of CHC in HCV mono-and HIV/HCV co-infected patients. Reduced expression of HMOX1 in patients with HIV/HCV co-infection may indicate a worse prognosis in this group. Our results do not support the importance of Bach-1 in repression of HMOX1 in patients with chronic hepatitis C.     

Iridoid glycosides from Gmelina arborea

Three iridoid glycosides 6-O-(3'-O-benzoyl)-alpha-l-rhamnopyranosylcatalpol (1a), 6-O-(3'-O-trans-cinnamoyl)-alpha-l-rhamnopyranosylcatalpol (2a) and 6-O-(3'-O-cis-cinnamoyl)-alpha-l-rhamnopyranosylcatalpol (3a) were isolated from aerial parts of Gmelina arborea and structures were elucidated by spectral analysis. Additionally a known iridoid 6-O-(3', 4'-O-dibenzoyl)-alpha-l-rhamnopyranosylcatalpol (4) was also isolated and identified.     

A genome-wide survey of imprinted genes in rice seeds reveals imprinting primarily occurs in the endosperm

Genomic imprinting causes the expression of an allele depending on its parental origin. In plants, most imprinted genes have been identified in Arabidopsis endosperm, a transient structure consumed by the embryo during seed formation. We identified imprinted genes in rice seed where both the endosperm and embryo are present at seed maturity. RNA was extracted from embryos and endosperm of seeds obtained from reciprocal crosses between two subspecies Nipponbare (Japonica rice) and 93-11 (Indica rice). Sequenced reads from cDNA libraries were aligned to their respective parental genomes using single-nucleotide polymorphisms (SNPs). Reads across SNPs enabled derivation of parental expression bias ratios. A continuum of parental expression bias states was observed. Statistical analyses indicated 262 candidate imprinted loci in the endosperm and three in the embryo (168 genic and 97 non-genic). Fifty-six of the 67 loci investigated were confirmed to be imprinted in the seed. Imprinted loci are not clustered in the rice genome as found in mammals. All of these imprinted loci were expressed in the endosperm, and one of these was also imprinted in the embryo, confirming that in both rice and Arabidopsis imprinted expression is primarily confined to the endosperm. Some rice imprinted genes were also expressed in vegetative tissues, indicating that they have additional roles in plant growth. Comparison of candidate imprinted genes found in rice with imprinted candidate loci obtained from genome-wide surveys of imprinted genes in Arabidopsis to date shows a low degree of conservation, suggesting that imprinting has evolved independently in eudicots and monocots.     

Mechanisms underlying the dual-mode regulation of microtubule dynamics by Kip3/kinesin-8

The kinesin-8 family of microtubule motors plays?a critical role in microtubule length control in cells. These motors have complex effects on microtubule dynamics: they destabilize growing microtubules yet stabilize shrinking microtubules. The budding yeast kinesin-8, Kip3, accumulates on plus ends of growing but not shrinking microtubules. Here we identify an essential role of the tail domain of Kip3 in mediating both its destabilizing and its stabilizing activities. The Kip3 tail promotes Kip3's accumulation at the plus ends and facilitates the destabilizing effect of Kip3. However, the Kip3 tail also inhibits microtubule shrinkage and is required for promoting microtubule rescue by Kip3. These effects of the tail domain are likely to be mediated by the tubulin- and microtubule-binding activities that we describe. We propose a concentration-dependent model for the coordination of the destabilizing and stabilizing activities of Kip3 and discuss its relevance to cellular microtubule organization.