Rac1 GTPase is activated by hepatitis B virus replication--involvement of HBX

Hepatitis B virus (HBV) is a causative agent for liver diseases including hepatocellular carcinoma. Understanding its interactions with cellular proteins is critical in the elucidation of the mechanisms of disease progression. Using a cell-based HBV replication system, we showed that HBV replication in HepG2 cells resulted in a cellular morphological changes displaying membrane rufflings and lamellipodia like structures reminiscent of cells expressing constitutively activated Rac1. We also showed that activated Rac1 resulted in increased viral replication. HBV replication specifically activated wild type Rac1, but not Cdc42. The Rac1 activation by HBV replication also resulted in the phosphorylation of ERK1/2 and AKT, the downstream targets of Rac1 signaling cascade. The smallest HBV viral protein, HBX, was able to activate the endogenous Rac1 and induce membrane ruffling when transfected into cells. Significantly, HBX was found to directly interact with a Rac1 nucleotide exchange factor (betaPIX) through a SH3 binding motif. Taken together, we have shown the interaction of HBV with the Rho GTPase, affecting cell morphology through the Rac1 activation pathway. HBV may possibly make use of an activated Rac1 signaling pathway for increased replication and resultant metastatic effects.     

Brain lipids of a case of juvenile Niemann-Pick disease

—Lipids of frontal lobe grey and white matter were examined in parallel from a normal and a diseased child (M. Niemann-Pick), both nine years of age. In the grey matter of the pathological case the following changes, although small, were found: a slight increase in all phospholipids and decreased values for nervonic acid in cerebrosides and for hydroxy fatty acids in sulphatides. White matter seemed much more affected by the disease: water content was about 6 per cent higher which corresponds to an approx. 20 per cent loss of dry substance compared with the normal brain. Further increases were observed in ‘ganglioside’ fraction and in all phosphatides. Cerebroside and sulphatide levels appeared decreased owing to destruction of myelin. In all of the glycerophosphatides oleic acid portions were lowered whereas in sphingolipids mainly nervonic acid values were reduced. Aldehyde content of both tissues seemed lowered in the disease, however, changes in composition were observed only in white matter, where the stearaldehyde portion of ethanolamine glycerophospholipid increased at the expense of palmitaldehyde and oleinaldehyde.     

A simple vertebrate collagenase assay using soluble radioactive collagen substrate

A highly sensitive assay for vertebrate collagenase has been developed using [14C]proline- or [3H]proline-labeled collagen as soluble substrate. The substrate was easy to prepare, gave high specific activity (1.4 X 10(6) cpm/mg collagen), and was stable at -20 degrees C for a long period. The digestion reaction for the assay was done at 21 degrees C to minimize the cleavage of collagen by proteases other than collagenase and to protect the 3/4 and 1/4 cleavage fragments of collagen from being further attacked by proteases. The cleaved products were denatured and then separated from undigested native collagen by precipitation with 1 M NaCl at pH 3.5. The conditions selected for denaturation and separation gave better discrimination between the cleaved products and uncleaved substrate than did conditions used in some other assays. The digestion products can be examined further by gel electrophoresis at the end of the assay to confirm the activity of vertebrate collagenase. This assay can also be adapted to assess telopeptidase activity independently of collagenase activity.     

Role of neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR) and mean platelet volume (MPV) in assessing disease control in Asian patients with axial spondyloarthritis

Introduction: C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) which are used for assessment of axial spondyloarthritis (AxSpA) related disease activity have poor specificity and sensitivity. Neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR) and mean platelet volume (MPV) have not been investigated as disease activity markers among Asian AxSpA patients.

Methodology: A retrospective, cross-sectional study was conducted in Singapore General Hospital from January 2013 to December 2015 to investigate the role of NLR, PLR and MPV as disease activity markers in AxSpA patients.

Results: The mean age of patients (n?=?122) was 37.0?±?12.5 years old and majority of them were male (n?=?93, 76.2%). No significant differences were found between patients with disease with regards to age, gender, ethnicity, HLAB-27 status, age at onset of diagnosis of AxSpA, duration of disease and comorbidities such as cardiac disease (p?>?0.05).

There were no significant differences in the ESR, NLR, PLR and MPV between the four disease activity groups (p?>?0.05). However, patients with very high disease activity had higher ESR and CRP compared to patients with inactive disease and moderate disease activity (p?Conclusion: NLR, PLR and MPV were not associated with disease activity in Asian AxSpA patients.     

Phosphorus nutrition of rice in relation to flooding and temporary loss of soil-water saturation in two lowland soils of Cambodia

In the rainfed lowlands, temporary loss of soil-water saturation during crop growth is a common factor limiting rice (Oryza sativa L.) yield but its effects on phosphorus (P) availability are poorly understood. Rice plants were transplanted into pots containing soils that were either continuously flooded, maintained at field capacity or flooded and then dried to field capacity for 3 weeks during the vegetative stage. A black clay soil (Kandic Plinthaquult) and a sandy soil (Plinthustalf) from south-east Cambodia were compared with or without amendments by rice straw and P fertilizer. Under continuously flooded conditions, the growth of rice was vigorous without straw addition and there was a strong response of rice growth to the addition of P fertilizer. The soil underwent reduction, which increased pH from 4.2 to 5.5 or 6.0, in the black clay or sandy soil, respectively. By contrast, a loss of soil-water saturation 3 weeks before panicle initiation (PI) markedly impaired the growth of rice. This was not through any effect of water stress, and the growth reductions were not as strong as with continued loss of soil-water saturation from transplanting to PI. Fluctuations in soil pH and Eh corresponded closely to changes in soil-water regimes. Growth reductions were attributed to reduced shoot P levels resulting from the decline in P availability during the loss of soil-water saturation. The addition of rice straw stimulated soil reduction and lessened changes in soil pH and Eh during the loss of soil-water saturation in both soils. Straw addition enhanced P uptake by the rice plants during loss of soil-water saturation, but its beneficial effects could not be attributed to the direct addition of P, N or K to the soils. Thus the application of rice straw may be effective in lessening the effects of temporary loss of soil-water saturation on rice growth in lowland rice soils by minimising the decline in P availability. This revised version was published online in August 2006 with corrections to the Cover Date.     

Karyotype Analysis of Hydrilla

The present paper reports the chromosome number and karyotype of the genus Hydrilla. H. verticillate was found to have 2n=16. The karyotype is 2n=16=6m+6sm+ 4st. No difference between the male and the female was found in the work. H. verticillata var. roxburghii Casp. has the somatic chromosome number 2n=24, and its karyotype is 2n= 3x=24=9m+9sm+6st. The variety may be a autotriploid. The karyotype of the genus isobviously bimodal, with No. 1-5 in the first group and 6-8 in the second group.     

Pseudomonas versuta sp. nov., isolated from Antarctic soil

In this study we analysed three bacterial strains coded L10.10^T, A4R1.5 and A4R1.12, isolated in the course of a study of quorum-quenching bacteria occurring in Antarctic soil. The 16S rRNA gene sequence was identical in the three strains and showed 99.7% pairwise similarity with respect to the closest related species Pseudomonas weihenstephanensis WS4993^T. Therefore, the three strains were classified within the genus Pseudomonas. Analysis of housekeeping genes (rpoB, rpoD and gyrB) sequences showed similarities of 84-95% with respect to the closest related species of Pseudomonas, confirming its phylogenetic affiliation. The ANI values were less than 86% to the closest related species type strains. The respiratory quinone is Q9. The major fatty acids are C16:0, C16:1 ω7c/ C16:1 ω6c in summed feature 3 and C18:1 ω7c / C18:1 ω6c in summed feature 8. The strains are oxidase- and catalase-positive. Growth occurs at 4–30 °C, and at pH 4.0–10. The DNA G+C content is 58.2–58.3 mol %. The combined genotypic, phenotypic and chemotaxonomic data support the classification of strains L10.10^T, A4R1.5 and A4R1.12 into a novel species of Pseudomonas, for which the name P. versuta sp. nov. is proposed. The type strain is L10.10^T (LMG 29628^T, DSM 101070^T).