Modes of DNA replication primed with the oligomer of palindrome

What is the precise molecular mechanism of semi-conservative DNA replication? After the great efforts of the past 20 years, molecular biology has now established the discontinuous syntheses of daughter DNA on both of the parental strands. In order to explain this type of discontinuous replication, we introduce the concept of a palindromic primer.First we focus our attention on various oligomers (RNA or DNA) which appear usually or occasionally in the process of replication. Then we propose the palindromic nature of these oligomers so as to serve as the primer of DNA synthesis. This postulation gives a theoretical reasoning for the discontinuities of both new strands in the fork region of replication.Subsequently we consider Watson's concatemeric intermediate theory, proposed for the explanation of replicative synthesis of phage T7 DNA. By considering the contribution of some sequence-specific endonuclease(s), we suggest the existence of partial palindromic sequences of bases at the connecting region(s) in which the redundant ends of the respective phage DNA molecules are overlapping. Another theory on the replication of linear chromosomal DNA including the concept of the terminal palindromic sequence of bases is also analyzed from the viewpoint of palindromic primer. Further, some recent experimental approaches, especially on the origin(s) of DNA replication, are shown to favour the concept of a palindromic primer.     

A case report on human type B botulism

A case of type B human botulism was found in Tochigi Prefecture in November, 1984. Botulinum type B toxin was detected in the serum and feces of the patient. The serum toxin was activated by trypsinization. Type B toxin was demonstrated in cooked meat medium cultures of the fecal specimens. The patient recovered after administration of type A, B, E and F quadrivalent antitoxin.     

Microorganism Capable of Decomposing N-Acetylglucosaminyl Ribitol Teichoic Acid of Staphylococcus aureus

Enzyme(s) capable of decomposing N-acetylglucosaminyl ribitol teichoic acid prepared from the cell wall of Staphylococcus aureus FDA 209 P was obtained from the culture supernatant of a gram-negative, rod-shaped, spore-forming soil bacterium. Properties of the bacterium were very similar to those of Bacillus circulans.     

Evaluation of oxidative stress based on lipid hydroperoxide, vitamin C and vitamin E during apoptosis and necrosis caused by thioacetamide in rat liver

After 12 h of thioacetamide (500 mg/kg body weight) administration to rats, the activity of caspase-3-like protease in the liver increased significantly compared to that in the control group. In plasma, the activity of caspase-3 was barely detectable in the control rat, but had increased significantly after 24 h of drug administration along with a dramatic increase in GOT. These results indicate that thioacetamide causes apoptosis in the liver by activating caspase-3, which is released to plasma by successive necrosis. At 24 h, the concentration of liver lipid hydroperoxides, a mediator of radical reaction, was 2.2 times as high as that of control rats. After 12 and 24 h of thioacetamide administration, the liver concentrations of vitamins C and E decreased significantly. The decrease of antioxidants and formation of lipid hydroperoxides 24 h after thioacetamide administration support the view that extensive radical reactions occur in the liver during the necrotic process.     

Sex- and age-related differences in morbidity rates of 2009 pandemic influenza A H1N1 virus of swine origin in Japan

Background

The objective of the present study was to determine whether the morbidity rates of the 2009 pandemic influenza A H1N1 virus (pdmH1N1) varied by age and/or sex.

Methods and Findings

Retrospective analysis of 2,024,367 cases of pdmH1N1 was performed using the national surveillance data from influenza sentinel points in Japan. The male-to-female morbidity ratios (M/F ratios) in nineteen age groups were estimated as the primary outcome. The M/F ratios for pdmH1N1 influenza were: >1 in age groups <20 years and ≥80 years (p<0.001); <1 in age groups 20–79 years (p<0.001). This data suggests that males <20 years of age may be more likely to suffer from pdmH1N1 influenza than females in the same age categories. When the infection pattern for pdmH1N1was compared with that of seasonal influenza outbreaks between 2000 and 2008, the M/F ratio for pdmH1N1 influenza was higher in ages 3–29 years and lower in ages 40–79 years. Because the present study was based on the national surveillance, it was impossible to estimate the morbidity rate for the Japanese population. It is also likely that the data did not capture asymptomatic or mild infections.

Conclusions

Although exposure to the pdmH1N1 virus is assumed to be similar in both boys and girls, M/F ratios were >1 in those younger than 20 years. The subsequent reversal of the M/F ratio in the adult generation could be due to several possibilities, including: greater immunity among adult males, more asymptomatic infections among males, less reporting of illness by males, or differences in exposure to the virus and probability of visiting a clinic. These results suggest that the infection and virulence patterns of pdmH1N1 are more complex than previously considered.     

Identification and partial characterization of soluble and membrane-bound KDN(deaminoneuraminic acid)-glycoproteins in human ovarian teratocarcinoma PA-1, and enhanced expression of free and bound KDN in cells cultured in mannose-rich media

KDN (Deaminoneuraminic acid, or deaminated neuraminic acid) is a minor but biosynthetically independent member of the sialic acid. Human occurrence of KDN has already been established, although its level is so little that it is often undetectable by conventional sialic acid analysis. Elevated expression of KDN in fetal cord blood cells and some malignant tumor cells have been reported. However, in mammalian cells and tissues KDN mostly occurs as the free sugar and little occurred conjugated to glycolipids and/or glycoproteins. A positive correlation between the ratio of free KDN/free Neu5Ac in ovarian adenocarcinomas and the stage of malignancy has been noted for diagnostic use. We hypothesized that elevated expression of KDN in mammalian systems may be closely related to elevated activities of enzymes involved in the formation of sialoglycoconjugates and/or aberrant supply of the precursor sugar, mannose, used in the biosynthesis of KDN. In this study we used human ovarian teratocarcinoma cells PA-1 to further analyze KDN expression in human cells. Major findings reported in this paper are, (i) a 30 kDa KDN-glycoprotein immunostainable with monoclonal antibody, mAb.kdn3G, (specific for the KDNα2 → 3Galβ1→ epitope) and sensitive to KDNase was identified in the membrane fraction of the cell: (ii) a 49 kDa KDN-glycoprotein that is not reactive with mAb.kdn3G but is sensitive to KDNase was identified in the soluble fraction: and (iii) PA-1 cells showed unique response to mannose added to the growth medium in that the levels of both free and bound forms of KDN are elevated. This is the first report on the identification of mammalian KDN-glycoproteins by chemical and biochemical methods.     

Ganglioside GD1a regulation of caveolin-1 and Stim1 expression in mouse FBJ cells:Augmented expression of caveolin-1 and Stim1 in cells with increased GD1a content

GD1a was previously shown responsible for regulating cell motility, cellular adhesiveness to vitronectin, phosphorylation of c-Met and metastatic ability of mouse FBJ osteosarcoma cells. To determine the particular molecules regulated by GD1a, FBJ cells were assessed for tumor-related gene expression by semi-quantitative RT-PCR. Caveolin-1 and stromal interaction molecule 1 (Stim1) expression in FBJ-S1 cells, rich in GD1a, were found to be 6 and 4 times as much, respectively, than in FBJ-LL cells devoid of GD1a. Enhanced production of caveolin-1 in protein was confirmed by Western blotting. A low-metastatic FBJ-LL cell variant, having high GD1a expression through β1-4GalNAcT-1 (GM2/GD2 synthase) cDNA transfection (Hyuga S, et al, Int J Cancer 83: 685-91, 1999), showed enhanced production of caveolin-1 and Stim1 in mRNA and protein, compared to mock-transfectant M5. Incubation of FBJ-M5 cells with exogenous GD1a augmented the expression of caveolin-1 in mRNA and protein and Stim1 in mRNA as well. Treatment of FBJ-S1 with fumonisin B1, an inhibitor of N-acylsphinganine synthesis, for 15 days caused the complete depletion of gangliosides and suppressed the expression of caveolin-1 and Stim1. St3gal5 siRNA transfected cells showed decreased expression of caveolin-1 and Stim1 mRNA, as well as St3gal5 mRNA. These findings clearly indicate ganglioside GD1a to be involved in the regulation of the transformation suppressor genes, caveolin-1 and Stim1. Moreover, treatment with GD1a of mouse melanoma B16 cells and human hepatoma HepG2 cells brought about elevated expression of caveolin-1 and Stim1. Li Wang and Shizuka Takaku are equal contributors to the present work     

Comparative study with two different enrichments in the culture media used in the disinfectant efficacy assay

Recent changes in Brazilian legislation for commercial disinfectants have been published due to the recent epidemic of nosocomial infections caused by rapidly growing mycobacteria (RGM) in many states of Brazil over the last 8 years. One of these documents requires that all the manufacturers provide evidence of efficacy of sterilizing and disinfectant products, used for semi critical medical devices, against the Mycobacterium bovis BCG Moreau and Mycobacterium abscessus subsp. bolletii INCQS 00594 strains by using the Confirmative in vitro Test for Determining Tuberculocidal Activity of Disinfectants recommended by the Association of Official Analytical Chemists. These changes have caused additional costs and increased problems for importation of enrichment products at national laboratories where disinfectant efficacy assay service is performed. Middlebrook ADC Enrichment (ADC) is provided by a unique manufacturer and used in the official protocol. The aim of the present study was to evaluate an alternative in house low-cost enrichment composed of fetal bovine serum and glucose (FBSG) with ADC for performance of disinfectant efficacy assay against mycobacteria. After obtaining the growth curves for M. abscessus ATCC 19977, M. abscessus subsp. bolletii INCQS 00594, Mycobacterium chelonae ATCC 35752, and Mycobacterium fortuitum ATCC 6841 by using ADC enrichment and FBSG in Kirchners and 7H9 culture media. Through statistical analysis via the Kruskal-Wallis test on the evaluation of microorganism growth rate, it was observed that there was no inhibition of RGM growth by any of the enrichments used. These results suggest that low-cost enrichment FBSG may be used as a potential substitute of ADC for composition of media for mycobacterial growth, including in disinfectant tests.