A critical role for Romo1-derived ROS in cell proliferation

Low levels of endogenous reactive oxygen species (ROS) originating from NADPH oxidase have been implicated in various signaling pathways induced by growth factors and mediated by cytokines. However, the main source of ROS is known to be the mitochondria, and increased levels of ROS from the mitochondria have been observed in many cancer cells. Thus far, the mechanism of ROS production in cancer cell proliferation in the mitochondria is not well-understood. We recently identified a novel protein, ROS modulator 1 (Romo1), and reported that increased expression of Romo1-triggered ROS production in the mitochondria. The experiments conducted in the present study showed that Romo1-derived ROS were indispensable for the proliferation of both normal and cancer cells. Furthermore, whilst cell growth was inhibited by blocking the ERK pathway in cells transfected with siRNA directed against Romo1, the cell growth was recovered by addition of exogenous hydrogen peroxide. The results of this study suggest that Romo1-induced ROS may play an important role in redox signaling in cancer cells.     

Long-term effects of resveratrol supplementation on suppression of atherogenic lesion formation and cholesterol synthesis in apo E-deficient mice

Atherosclerosis is a chronic inflammatory disease of the arteries resulting from interactions between lipids, monocytes, and arterial wall cells. The effects of resveratrol supplements (RV, 0.02% and 0.06% each, w/w) with regard to the modulation of lipid profiles, cholesterol synthesis, and anti-atherogenesis were examined in apo E-deficient (apo E^−/−) mice fed a normal diet. The concentration of total-cholesterol (total-C) and LDL-cholesterol (LDL-C) in plasma was significantly lower in the resveratrol-supplemented groups compare to the control group over the entire experimental period. The plasma HDL-C concentration was significantly elevated, and the ratio of HDL-C/total-C was significantly higher in the CF and RV groups than in the control group. Plasma paraoxonase (PON) activity was significantly higher in the 0.06% resveratrol group. The hepatic HMG-CoA reductase (HMGR) activity was significantly lower in the clofibrate and resveratrol groups than in the control group. Resveratrol supplements attenuated the presence of atherosclerotic lesions and periarterial fat deposition in the apo E^−/− mice. The presence of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in atherosclerotic vessels was diminished in the resveratrol-supplemented apo E^−/− mice. These results provide new insight into the anti-atherogenic and hypocholesterolemic properties of resveratrol in apo E^−/− mice that were fed a normal diet.     

Biochemical characterization and sequence analysis of a xylanase produced by an exo-symbiotic bacterium of <Emphasis Type="Italic">Gryllotalpa orientalis</Emphasis>, <Emphasis Type="Italic">Cellulosimicrobium</Emphasis> sp. HY-12

An exo-symbiotic bacterium capable of hydrolyzing xylan was isolated from the gut of the mole cricket, Gryllotalpa orientalis, and identified as Cellulosimicrobium sp. HY-12. The xylanase (XylA _CspHY-12) of this organism bound tightly to both DEAE and mono Q resins, and its molecular mass (M _r) was about 39.0 kDa. The highest xylanase activity was observed at pH 6.0 and 60°C. The enzyme was greatly suppressed by Ca²⁺, Cu²⁺, Co²⁺, and Fe²⁺ ions but not by Mg²⁺ and Mn²⁺. Although XylA _CspHY-12 was capable of hydrolyzing various types of xylosic compounds, it could not decompose carboxymethyl cellulose or xylobiose. The xylA _CspHY-12 gene consisted of an 1,188 bp open reading frame that encoded a polypeptide of 395 amino acids with a deduced molecular mass of 42,925 Da. The domain structure of XylA _CspHY-12 was most similar to those of the glycoside hydrolase (GH) family 10 endoxylanases. However its sequence identity with any of the enzymes in this family was below 52%. The results of this study suggest that the XylA _CspHY-12 is a new cellulase-free endo-β-1,4-xylanase with some properties that are distinct from those of GH family 10.     

Meiotic behaviour in three interspecific three-way hybrids between Brachiaria ruziziensis and B. brizantha (Poaceae: Paniceae)

The meiotic behaviour of three three-way interspecific promising hybrids (H17, H27, and H34) was evaluated. These hybrids resulted from the crosses between B. ruziziensis X B. brizantha and crossed to another B. brizantha. Two half-sib hybrids (H27 and H34) presented an aneuploid chromosome number (2n = 4x = 33), whereas hybrid H17 was a tetraploid (2n = 4x = 36), as expected. Chromosome paired predominantly as multivalents suggesting that genetic recombination and introgression of specific target genes from B. brizantha into B. ruziziensis can be expected. Arrangement of parental genomes in distinct metaphase plates was observed in H27 and H34, which have different male genitors. Hybrids H17 and H34 have the same male genitor, but did not display this abnormality. In H17, abnormalities were more frequent from anaphase II, when many laggard chromosomes appeared, suggesting that each genome presented a different genetic control for meiotic phase timing. Despite the phylogenetic proximity among these two species, these three hybrids presented a high frequency of meiotic abnormalities, mainly those related to irregular chromosome segregation typical of polyploids, H34, 69.1%; H27, 56.1% and H17, 44.9%. From the accumulated results obtained through cytological studies in Brachiaria hybrids, it is evident that cytogenetical analysis is of prime importance in determining which genotypes can continue in the process of cultivar development and which can be successfully used in the breeding. Hybrids with high frequency of meiotic abnormalities can seriously compromise seed production, a key trait in assuring adoption of a new apomictic cultivar of Brachiaria for pasture formation.     

IL-15 treatment during acute simian immunodeficiency virus (SIV) infection increases viral set point and accelerates disease progression despite the induction of stronger SIV-specific CD8+ T cell responses

In this study, we examined the effect of in vivo treatment of acutely SIV-infected Mamu-A*01+ rhesus macaques with IL-15. IL-15 treatment during acute infection increased viral set point by 3 logs and accelerated the development of simian AIDS in two of six animals with one developing early minimal lesion SIV meningoencephalitis. Although IL-15 induced a 2- to 3-fold increase in SIV-specific CD8+ T cell and NK cell numbers at peak viremia and reduced lymph node (LN) SIV-infected cells, this had no impact on peak viremia and did not lower viral set point. At viral set point, however, activated SIV-specific CD8+ T cells and NK cells were reduced in the blood of IL-15-treated animals and LN SIV-infected cells were increased. Week 30 LN from IL-15-treated animals had significantly increased Gag-specific CD8+ T cell numbers, whereas total cell, lymphocyte, and CD4+ T cell numbers were reduced. IL-15 treatment significantly reduced anti-SIV Ab concentrations at week 3 and viral set point. IL-15 increased Ki-67+CD4+ T cells at week 1 of treatment and reduced blood CCR5+ and CD45RA-CD62L- CD4+ T cells. The frequency of day 7 Ki-67+CD4+ T cells strongly correlated with viral set point. These findings suggest that CD4+ T cell activation during acute infection determines subsequent viral set point and IL-15 treatment by increasing such activation elevates viral set point. Finally, IL-15-treated acutely SIV-infected primates may serve as a useful model to investigate the poorly understood mechanisms that control viral set point and disease progression in HIV infection.     

Human Taeniasis and Cysticercosis and Related Factors in Phu Tho Province,Northern Vietnam

Several factors presumed to facilitate the transmission of Taenia spp. were reported in Vietnam. We conducted a cross-sectional study taking questionnaires from 1,185 participants, and collecting 1,151 sera and 1,036 stool samples in northern Vietnam. Sera were examined for circulating antigens of Taenia solium cysticerci using ELISA, stools for Taenia eggs by Kato-Katz smear, and copro-antigens by ELISA. Ag-ELISA revealed 4.6% antigen positivity, indicating infection with viable cysticerci. Taenia eggs were detected in 1.5% of participants. Copro-antigens were found in 2.8% of participants. Eating raw meat and/or vegetables was significantly associated with the presence of copro-antigen (OR=8.6, 95% CI: 1.16–63.9, P=0.01). Considering the high taeniasis prevalence and the associated threat, public health attention should be given to treat the tapeworm carriers in the projected areas.     

Role of Rhodobacter sp. Strain PS9, a Purple Non-Sulfur Photosynthetic Bacterium Isolated from an Anaerobic Swine Waste Lagoon, in Odor Remediation

Temporal pigmentation changes resulting from the development of a purple color in anaerobic swine waste lagoons were investigated during a 4-year period. The major purple photosynthetic bacterium responsible for these color changes and the corresponding reductions in odor was isolated from nine photosynthetic lagoons. By using morphological, physiological, and phylogenetic characterization methods we identified the predominant photosynthetic bacterium as a new strain of Rhodobacter, designated Rhodobacter sp. strain PS9. Rhodobacter sp. strain PS9 is capable of photoorganotrophic growth on a variety of organic compounds, including all of the characteristic volatile organic compounds (VOC) responsible for the odor associated with swine production facilities (J. A. Zahn, A. A. DiSpirito, Y. S. Do, B. E. Brooks, E. E. Copper, and J. L. Hatfield, J. Environ. Qual. 30:624-634, 2001). The seasonal variations in airborne VOC emitted from waste lagoons showed that there was a 80 to 93% decrease in the concentration of VOC during a photosynthetic bloom. During the height of a bloom, the Rhodobacter sp. strain PS9 population accounted for 10% of the total community and up to 27% of the eubacterial community based on 16S ribosomal DNA signals. Additional observations based on seasonal variations in meteorological, biological, and chemical parameters suggested that the photosynthetic blooms of Rhodobacter sp. strain PS9 were correlated with lagoon water temperature and with the concentrations of sulfate and phosphate. In addition, the photosynthetic blooms of Rhodobacter sp. strain PS9 were inversely correlated with the concentrations of protein and fluoride.     

Phosphate Immobilization by Oxide Precursors: Implications on Phosphate Availability before Life on Earth

The present study is based on the proposal that if the aqueous phosphorus-capture mechanism by iron oxide precursors was inhibited in prebiotic anoxic scenarios then soluble phosphates could have been more available than what is observed now. Supporting this conjecture, we examine prevailing contemporary trapping mechanisms of orthophosphate (Pi) and pyrophosphate (PPi). To illustrate its efficiency, the attachment of (Pi) ontoaggregates of iron-3 oxyhydroxide is compared with the one reported for the product of its condensation, PPi. The electrophoretic profiles of the Pi- and PPi-aggregatecomplexes reveal different pH-modulated interactions ofthe phosphorylated compounds with both the aggregate andits aqueous surrounding layers. The observed differencesof Pi/PPi sorption and desorption mechanisms are discussed in terms of their consequences to the prebiotic availability of soluble orthophosphate and of a phosphorylated compound having the high-energy phosphoanhydride linkage and a molecule representative of condensed oligophosphates.