Isolation and characterization of tannin-degrading bacteria from the rumen of wild Hokkaido sika deer (Cervus nippon yezoensis)

We isolated tannin-degrading bacteria from the rumen of wild Hokkaido sika deer and characterized their phylogeny and tannase activity in relation to sample sources. The condensed tannin level was higher in all deer rumen samples (n = 20) than in forage-fed cattle rumen samples (n = 6), whereas no hydrolyzable tannins were detected in any of the rumen samples. Rumen bacteria were enumerated on nonselective brain heart infusion (BHI) agar medium and then transferred onto tannic acid-containing BHI agar plates to screen for bacteria only showing growth (tannin-resistant bacteria) and those showing both growth and a clear zone (tannin-degrading bacteria). Summer samples provided only tannin-resistant bacteria, none of which showed tannin-degrading activity. Although winter samples also provided tannin-resistant bacteria, most isolates exhibited tannin-degrading activity. A total of 70 isolates exhibiting tannin-degrading activity were classified as Streptococcus bovis group based on 16S rRNA gene sequencing and further classified into two groups, either group A or group B. Group A consisted of isolates showing weak tannase activity, whereas group B included a majority of the isolates exhibiting high tannase activity. These results suggest that wild Hokkaido sika deer develop tannin-degrading Streptococcus in the rumen during winter, which allows access to woody food materials rich in tannins.

Decadal stability in coral cover could mask hidden changes on reefs in the East Asian Seas

Coral reefs in the Central Indo-Pacific region comprise some of the most diverse and yet threatened marine habitats. While reef monitoring has grown throughout the region in recent years, studies of coral reef benthic cover remain limited in spatial and temporal scales. Here, we analysed 24,365 reef surveys performed over 37 years at 1972 sites throughout East Asia by the Global Coral Reef Monitoring Network using Bayesian approaches. Our results show that overall coral cover at surveyed reefs has not declined as suggested in previous studies and compared to reef regions like the Caribbean. Concurrently, macroalgal cover has not increased, with no indications of phase shifts from coral to macroalgal dominance on reefs. Yet, models incorporating socio-economic and environmental variables reveal negative associations of coral cover with coastal urbanisation and sea surface temperature. The diversity of reef assemblages may have mitigated cover declines thus far, but climate change could threaten reef resilience. We recommend prioritisation of regionally coordinated, locally collaborative long-term studies for better contextualisation of monitoring data and analyses, which are essential for achieving reef conservation goals.

Seasonal differences in rumen bacterial flora of wild Hokkaido sika deer and partial characterization of an unknown bacterial group possibly involved in fiber digestion in winter

Rumen digesta was obtained from wild Hokkaido sika deer to compare bacterial flora between summer and winter. Bacterial flora was characterized with molecular-based approaches and enrichment cultivation. Bacteroidetes was shown as a major phylum followed by Firmicutes, with similar proportions in both seasons. However, two phylogenetically unique groups in Bacteroidetes were found in each season: unknown group A in winter and unknown group B in summer. The ruminal abundance of unknown group A was the highest followed by Ruminococcus flavefaciens in winter. Moreover, the abundance of these two was higher in winter than in summer. In contrast, the abundance of unknown group B was higher in summer than in winter. In addition, this group showed the highest abundance in summer among the bacteria quantified. Unknown group A was successfully enriched by cultivating with oak bark and sterilized rumen fluid, particularly that from deer. Bacteria of this group were distributed in association with the solid rather than the liquid rumen fraction, and were detected as small cocci. Accordingly, unknown group A is assumed to be involved in degradation of fibrous materials. These results suggest that wild Hokkaido sika deer develop a rumen bacterial flora in response to changes in dietary conditions.

Catalysts for direct H2O2 synthesis taking advantage of the high H2 activating ability of Pt: kinetic characteristics of Pt catalysts and new additives for improving H2O2 selectivity

To develop efficient catalysts for the direct H₂O₂ synthesis from H₂ and O₂ by taking advantage of the high H₂ activating ability of Pt, kinetic studies of the H₂–O₂ reaction were performed using a Pt-PVP (polyvinylpyrrolidone) colloid and Pt supported on carbon (Pt/C) as catalysts, and new additives were explored.

Management of angiogram-negative acute colonic hemorrhage: safety and efficacy of colonoscopy-guided superselective embolization

BACKGROUND

We evaluated the efficacy and safety of superselective embolization with assistance of colonoscopy for acute colonic hemorrhage.

METHODS

Of 92 cases of acute colonic hemorrhage requiring colonoscopic intervention, 11 (12 %) could not be successfully treated. Of these, 10 patients (9 men, mean age 65.5 years, range 39-75 years) underwent superselective embolization. Hemorrhage was caused by diverticular disease (n = 8), polypectomy (n = 1), and vascular malformation (n = 1). In all 10 cases, the radiopaque clips were placed at the bleeding point via colonoscopy. Microcatheters were used in all procedures, and embolization was performed at the level of the vasa recta leading to or near the clips with Gelfoam particles, microcoils, or both.

RESULTS

Immediate hemostasis was achieved in all patients. In 6 of 10 patients (60 %), selective angiograms showed no active extravasation at the time of the procedure and the embolization was performed using clips as a landmark. In the remaining four patients, selective angiograms showed active extravasation from the vasa recta leading to the clips. The mean number of embolized vessels with no active extravasation and with active extravasation was 1.83 (range 1-3) and 1.25 (range 1-2), respectively. The mean duration of clinical follow-up was 11.6 months (range 1-29 months). One patient (10 %) bled from a different site than the treated site a month after embolization, but the bleeding ceased after endoscopic intervention. All the patients (100 %) were evaluated for objective evidence of ischemia by colonoscopy. Four of the 10 patients (40 %) were found endoscopically to have small areas of ischemia involving only the mucosa, but they remained asymptomatic. There was no bowel infarction or stricture.

CONCLUSIONS

Colonoscopy-assisted superselective embolization may be a safe and useful procedure for acute colonic hemorrhage without active extravasation on angiogram.

Protein phosphatases and cell division cycle control

Fission yeast has at least ten protein phosphatase genes that appear to play distinct roles in cell cycle control. Because of functional overlap, a clear lethal phenotype can be obtained only after multiple genetic alterations. Cells that have lost the protein phosphatase 1 (PP1)-like dis2/sds21 phosphatase activities prematurely enter mitosis and remain in a defective mitotic state with high H1 kinase activity and without sister chromatid disjunction. The same phenotype can be obtained in the presence of hydroxyurea. Overexpression of PP1-like phosphatase, on the other hand, delays the entry into mitosis. Cells that have lost PP2A-like ppa2 phosphatase activity also prematurely enter mitosis with a reduction in cell size. This semi-wee phenotype is enhanced in delta ppa2 mutants treated with the phosphatase inhibitor, okadaic acid. Genetic interactions between ppa2 and mitotic regulators suggest that ppa1/ppa2 phosphatase may directly or indirectly inhibit p34cdc2/cyclin kinase. Thus both PP1- and PP2A-like phosphatases in fission yeast may negatively regulate entry into mitosis. The major property of the dis2/sds21 mutant which is distinct from those of the ppa2/ppa1 mutant is its failure to inactivate the p34cdc2/cyclin complex after entry into mitosis. A novel phosphatase regulator encoded by sds22+ binds to dis2 phosphatase and controls the substrate specificity which appears to become essential in the progression from metaphase to anaphase.

delta15N of seagrass leaves for monitoring anthropogenic nutrient increases in coral reef ecosystems

In a coral reef environment, a slight increase in dissolved inorganic nitrogen (DIN;> or =1.0 micro M) can alter the ecosystem via macroalgal blooms. We collected seagrass leaves from the tropical and subtropical Pacific Ocean in five countries and examined the interactions between nutrient concentrations (C, N, P), molar ratios of nutrients, and delta15N to find a possible indicator of the DIN conditions. Within most sites, the concentrations of nutrients and their molar ratios showed large variations owing to species-specific values. On the other hand, almost identical delta15N values were found in seagrass leaves of several species at each site. The correlations between delta15N and nutrient concentrations and between delta15N and molar ratios of nutrients suggested that nutrient availability did not affect the delta15N value of seagrass leaves by altering the physiological condition of the plants. Increases in delta15N of seagrass leaves mostly matched increases in DIN concentrations in the bottom water. We suggest that delta15N in seagrass leaves can be a good tool to monitor time-integrated decrease/increase of DIN concentrations at a site, both in the water column and the interstitial water.

Endoscopic mucosal resection of the colon: the Japanese technique

Early colorectal neoplasms, especially flat-type and depressed-type lesions, should be treated with an EMR technique. In general because depressed-type lesions, in contrast to flat-type or protruded-type lesions, tend to invade the submucosa rapidly, they ought to be treated by EMR at an early stage. Histopathologically in the case of lesions that only minimally invade the submucosa without vessel invasion (sm1a and sm1b without vessel invasion), a treatment can be completed with EMR. Massive submucosal invasive cancers ought to be resected by surgical treatment because of the risk of recurrence or metastasis. In addition, pit pattern diagnosis with magnifying colonoscopy is useful to determine a therapeutic method for colonic neoplasms. Lesions with the type VN pit pattern represent malignancy and usually invade the submucosa massively, so it is better to treat them surgically from the outset. Endoscopic mucosal resection should be conducted under fully controlled endoscopy to prevent complications. EMR is a superior therapeutic method and will be performed frequently in the future. It is necessary for colonoscopists to determine a suitable therapy for each colorectal neoplastic lesion. They also need to master the EMR technique in the correct manner.

Lymph folliculitis in ulcerative colitis

Preferential involvement of the appendix has recently been confirmed in ulcerative colitis. Since the appendix is an aggregate of lymph follicles, this new observation implies a critical role of the lymph follicles, of both the large bowel and the appendix, in an etiopathogenesis of ulcerative colitis. This report presents two cases of ulcerative colitis in which lymph folliculitis and lymphoid hyperplasia were observed. Lymph folliculitis was observed endoscopically in a border between an established lesion and an uninvolved area. Case 1, proctitis type, relapsing remitting, mild in severity, showed lymph folliculitis in a proximal border of an established rectal lesion. Case 2, with left-sided colitis, mild in severity, had a skip appendiceal orifice inflammation. Lymph folliculitis was observed in the cecum surrounding established appendiceal orifice inflammation. In both cases, lymphoid hyperplasia was observed in an uninvolved area with clear vascular patterns. These two cases clearly demonstrate the involvement of gut lymph follicles in ulcerative colitis. Lymph folliculitis and/or lymphoid hyperplasia was proposed to be early lesions in ulcerative colitis. In addition, the need for microbiology targeting lymph follicles of the large bowel and appendix is stressed in order to disclose the casual microbial agents in ulcerative colitis.

The spike of S phase cyclin Cig2 expression at the G1-S border in fission yeast requires both APC and SCF ubiquitin ligases

We describe a novel set of oscillation mechanisms for the fission yeast S phase cyclin Cig2, which contains an authentic destruction box and is destroyed at anaphase via the APC/cyclosome (APC/C). Unlike the mitotic cyclin Cdc13, however, Cig2 mRNA and protein peak at the G1/S boundary and decline to low levels in G2 and M phases. We show here that SCF(Pop1, Pop2) plays a role in transcriptional periodicity, as pop mutations result in constitutive cig2(+) transcripts. The instability of Cig2 during G2 and M is independent of either the APC/C or Pop1/Pop2, but requires Skp1, a core component of SCF. These data indicate that the APC/C and SCF control Cig2 levels differentially at different stages of the cell cycle.

Colonoscopic diagnosis and management of nonpolypoid early colorectal cancer

Nonpolypoid colorectal neoplasms are grossly classified into three groups: slightly elevated (small flat adenomas), laterally spreading, and depressed. Flat adenomas are not invasive until they are rather large, whereas depressed lesions can invade the submucosa even when they are extremely small. Nonpolypoid lesions are difficult to detect and are often overlooked. Keys to detect them are their slight color change, interruption of the capillary network pattern, slight deformation of the colonic wall, spontaneously bleeding spots, shape change of the lesion with insufflation and deflation of air, and interruption of the innominate grooves. Spraying of indigo carmine dye helps to clarify the lesions. A pit pattern analysis with a zoom colonoscope is useful for the diagnosis and staging of early colorectal cancer. Small flat adenomas are thought to be precursors of protruded polyps and lateral spreading tumors, whereas depressed lesions are thought to grow endophytically and become advanced cancers. Small depressed lesions are treated with an endoscopic mucosal resection (EMR) technique; but when they massively invade the submucosa, surgical resection is indicated. Laterally spreading tumors are not as invasive despite their large size and therefore are good indications for the EMR or piecemeal EMR method. Small flat adenomas need not be treated urgently, as almost none is invasive. Accurate diagnosis with dye-spraying and zoom colonoscopy is vital for deciding the treatment strategy.

Carrier-mediated transport systems for glucose in mucosal cells of the human oral cavity

The in vitro uptake study was performed using the isolated cells of human oral mucosa, buccal and the dorsum of the tongue, to investigate the mechanisms of glucose uptake. The uptake of D-glucose was much larger in cells of the dorsum of the tongue than in buccal cells and was inhibited more extensively by 2-deoxy-D-glucose, a substrate of facilitative glucose transporters, than by alpha-methyl-D-glucoside, a specific substrate of SGLT1, suggesting the larger contribution of a facilitative transporter than Na(+)/glucose cotransporter. Furthermore, from the results of inhibition studies by several sugar analogues including maltose and D-mannose, GLUT1 and/or GLUT3 were suggested to take part in the glucose uptake by oral mucosa. Therefore, we have attempted to confirm the expression of glucose transporters on the oral mucosa by employing Western blotting. As a result, it was suggested that SGLT1, GLUT1, GLUT2, and GLUT3 are expressed in the epithelial cells of human oral mucosa.

The risk of hepatitis C virus infection among blood donors in Osaka, Japan

To estimate the risk of hepatitis C virus (HCV) infection among blood donors, we conducted a retrospective cohort study with 448,020 HCV-seronegative donors who donated blood more than once between February 1992 and July 1997 in Osaka (a total of 2,676,738 allogeneic blood donations). The donors were divided into four age groups according to the age at the initial donation: Group A (16-24 years), Group B (25-34 years), Group C (35-49 years) and Group D (50-64 years). Fifty-nine donors became infected with HCV among the 448,020 HCV-seronegative donors who donated blood more than once within a period of approximately five years. In a total of 1,095,668 person-years of observation (PYO), the incidence rate was 5.38 per 105 PYO, with the 95% confidence interval (95% C.I.) being 4.10 to 6.95. There was no significant difference in the incidence rate between males and females. Young donors between the ages of 16 and 24 (8.89; 95% C.I., 6.04 to 12.61) had a significantly higher incidence rate of HCV infection than donors between the ages of 35 and 49 (1.81; 0.67 to 3.95). The cumulative risk of HCV infection among donors between the ages of 16 and 64 was estimated to be 0.27% (95% C.I., 0.16 to 0.39) for males and 0.27% (95% C.I., 0.15 to 0.38) for females. Based on the recent age-specific incidence rate, the cumulative risk of HCV infection among blood donors was estimated to be about 0.3% in the Osaka district of Japan. The incidence rate differed among age groups, indicating that HCV infection is associated with age-related behaviors and the need for further epidemiological research towards the eradication of community-acquired HCV infection.

Hepatitis C virus 1b(II) infection and development of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma: a case-control study in Japan

This study was performed to determine the distribution of hepatitis C virus (HCV) genotypes among asymptomatic carriers (ASC) and patients with chronic hepatitis without cirrhosis (NC-CH), liver cirrhosis (LC), and hepatocellular carcinoma (HCC) in the Osaka area, and to assess whether infection with HCV genotype 1b (II) is more likely to develop into hepatocellular carcinoma (HCC) than is that with genotype 2a (III) or genotype 2b (IV). Genotypes of all study subjects were determined by Okamoto's method. HCV genotype 1b was detected in 100 of the 143 ASC (69.9%), 551 of the 726 NC-CH patients (75.9%), 86 of the 103 patients with LC (83.5%), and 153 of the 179 HCC (85.5%) patients. Using unconditional logistic regression analysis, the age- and sex- adjusted odds ratios contrasting NC-CH with ASC, LC with ASC and HCC with ASC were 1.38 [95% confidence interval (CI) = 0.93-2.05], 2.28 (95% CI = 1.12-4.63) and 2.27 (95% CI = 1.02-5.06) respectively. HCV genotype 1b is predominant in both healthy carriers and patients with chronic liver diseases in the Osaka area. The findings from the three case-control studies indicate that type 1b infection is more closely associated with the development of LC and HCC than type 2a or 2b through its role in the progression of chronic liver inflammation to a cirrhotic stage.

The role of the destruction box and its neighbouring lysine residues in cyclin B for anaphase ubiquitin-dependent proteolysis in fission yeast: defining the D-box receptor

Programmed proteolysis of proteins such as mitotic cyclins and Cut2/Pds1p requires a 9-residue conserved motif known as the destruction box (D-box). Strong expression of protein fragments containing destruction boxes, such as the first 70 residues of Cdc13 (N70), inhibits the growth of Schizosaccharomyces pombe at metaphase. This inhibition can be overcome either by removal of all lysine residues from N70 using site-directed mutagenesis (K0-N70) or by raising the concentration of intracellular ubiquitin. Consistent with the idea that competition for ubiquitin accounts for some of its inhibitory effects, wild-type N70 not only stabilized D-box proteins, but also Rum1 and Cdc18, which are degraded by a different pathway. The K0-N70 construct was neither polyubiquitinated nor degraded in vitro, but it blocked the growth of strains of yeast in which anaphase-promoting complex/cyclosome (APC/C) function was compromised by mutation, and specifically inhibited proteolysis of APC/C substrates in vivo. Both K0-N70 and 20-residue D-box peptides blocked polyubiquitination of other D-box-containing substrates in a cell-free ubiquitination assay system. These data suggest the existence of a D-box receptor protein that recognizes D-boxes prior to ubiquitination.

Fission yeast Cut2 required for anaphase has two destruction boxes

The fission yeast Schizosaccharomyces pombe cut2(+) gene is essential for sister chromatid separation. Cut2 protein, which locates in the interphase nucleus and along the metaphase spindle, disappears in anaphase with the same timing as mitotic cyclin destruction. This proteolysis depends on the APC (Anaphase-Promoting Complex)-cyclosome which contains ubiquitin ligase activity. The N-terminus of Cut2 contains two stretches similar to the mitotic cyclin destruction box. We show that both sequences (33RAPLGSTKQ and 52RTVLGGKST) serve as destruction boxes and are required for in vitro polyubiquitination and proteolysis. Cut2 with doubly mutated destruction boxes inhibits anaphase, whereas Cut2 with singly mutated boxes can suppress cut2 mutations. Strong expression of the N-terminal 73 residues containing the destruction boxes leads to the accumulation of endogenous cyclin and Cut2, and arrests cells in metaphase, whereas the same fragment with the mutated boxes does not. Cut2 proteolysis occurs in vitro using Xenopus mitotic extracts in the presence of functional destruction boxes. Furthermore, Cut2 is polyubiquitinated in an in vitro system using HeLa extracts, and this polyubiquitination requires the destruction boxes.

The role of proteolysis in cell cycle progression in Schizosaccharomyces pombe

A cell-free system derived from Xenopus eggs was used to identify the 'destruction box' of the Schizosaccharomyces pombe B-type cyclin, Cdc13, as residues 59-67: RHALDDVSN. Expression of indestructible Cdc13 from a regulated promoter in S.pombe blocked cells in anaphase and inhibited septation, showing that destruction of Cdc13 is necessary for exit from mitosis, but not for sister chromatid separation. In contrast, strong expression of a polypeptide comprising the N-terminal 70 residues of Cdc13, which acts as a competitive inhibitor of destruction box-mediated proteolysis, inhibited both sister chromatid separation and the destruction of Cdc13, whereas an equivalent construct with a mutated destruction box did not. Appropriately timed expression of this N-terminal fragment of Cdc13 overcame the G1 arrest seen in cdc10 mutant strains, suggesting that proteins required for the initiation of S phase are subject to destruction by the same proteolytic machinery as cyclin.

Diagnosis of colorectal tumorous lesions by magnifying endoscopy

BACKGROUND

The magnifying colonoscope allows 100-fold magnified viewing of the colonic surface.

METHODS

We examined 2050 colorectal tumorous lesions by magnifying endoscopy, stereomicroscopy, and histopathology and classified these lesions according to pit pattern. Based on stereomicroscopy, lesions with a type 1 or 2 pit pattern were nontumors, whereas lesions with types 3s, 3L, 4, and/or 5 pit patterns were neoplastic tumors.

RESULTS

The pit patterns observed by magnifying endoscopy were fundamentally similar to those demonstrated in stereomicroscopic images. When the diagnosis by magnifying endoscopy was compared with the stereomicroscopic diagnosis, there was agreement in 1130 of 1387 lesions (81.5%). True neoplasms could be differentiated from non-neoplastic lesions. Of lesions with a type 5 pit pattern with a bounded surface, 11 of 22 (50%) were found to be invasive cancers with involvement of the submucosal layer. If this pit pattern is found to involve a relatively broad area of the mucosal surface, extensive malignant invasion (sm-massive) should be strongly suspected.

CONCLUSIONS

The magnifying colonoscope provides an accurate instantaneous assessment of the histology of colorectal tumorous lesions. This may help in decision making during colonoscopy.

Cut2 proteolysis required for sister-chromatid seperation in fission yeast

Although mitotic cyclins are well-known substrates for ubiquitin-mediated proteolysis at the metaphase-anaphase transition, their degradation is not essential for separation of sister chromatids; several lines of evidence suggest that proteolysis of other protein(s) is required, however. Here we report the anaphase-specific proteolysis of the Schizosaccharomyces pombe Cut2 protein, which is essential for sister-chromatid separation. Cut2 is located in the nucleus, where it is concentrated along the short metaphase spindle. The rapid degradation of Cut2 at anaphase requires its amino-terminal region and the activity of Cut9 (ref. 14), a component of the 20S cyclosome/anaphase-promoting complex (APC), which is necessary for cyclin destruction. Expression of non-degradable Cut2 blocks sister-chromatid separation but not cell-cycle progression. This defect can be overcome by grafting the N terminus of cyclin B onto the truncated Cut2, demonstrating that the regulated proteolysis of Cut2 is essential for sister-chromatid separation.

The problem of de novo colorectal carcinoma

From April 1985 to March 1995, colonoscopy was carried out at our institution in 24,059 patients, 31,800 times in symptomatic and/or asymptomatic average risk persons. 184 submucosal invasive carcinomas were detected. Unlike protruding-type lesion, the depressed-type invades the submucosal layer, even though the size is within 10 mm. The depressed type of invasive carcinoma accounted for 20 lesions, and represented 10.9% (20 of 184) of all the invasive carcinomas. The pit pattern of depressed-type lesions shows a small round pit (type IIIs pit pattern) and that of carcinoma lesions shows the irregular pit and non-structure (type V pit pattern).

Phosphorylation of dis2 protein phosphatase at the C-terminal cdc2 consensus and its potential role in cell cycle regulation

We show that the fission yeast dis2 protein phosphatase, which is highly similar to mammalian type 1 phosphatase, is a phosphoprotein containing phosphoserine (phospho-S) and threonine (phospho-T). It has several phosphorylation sites, two of which locate in the C-terminus. Phospho-T was abolished in the alanine substitution mutant at the C-terminal T316, which is conserved as a residue in the cdc2 consensus, TPPR, in a number of type 1-like phosphatases. In G2-arrested cdc2-L7 cells, the degree of T316 phosphorylation was reduced, whereas it was enhanced in metaphase-arrested nuc2-663 mutant cells. Phospho-T was produced in dis2 by fission yeast cdc2 kinase, but not in the substitution mutant A316, indicating that the T316 residue was the site for cdc2 kinase in vitro. Phosphatase activity of wild type dis2 was reduced by incubation with cdc2 kinase, but that of mutant dis2-A316 was not. Phosphorylation of T316 hence has a potential significance in cell cycle control in conjunction with cdc2 kinase activation and inactivation. Overexpression phenotypes of wild type dis2+, sds21+ and mutant dis2-A316, sds21-TPPR genes were consistent with negative regulation of dis2 by phosphorylation. This type of regulation would explain why cells harboring the dis2-11 mutation enter mitosis but fail to exit from it.

Prevalence of second generation antibody to hepatitis C virus among voluntary blood donors in Osaka, Japan

To clarify the demographic characteristics of the prevalence of hepatitis C virus (HCV) infection in Osaka, Japan, where hepatocellular carcinoma is common, we investigated the screening data of antibody to HCV (anti-HCV, DAINABOTHCVPHA, second generation assay) in 197,600 voluntary blood donors residing in Osaka. The study found that age-standardized prevalence of anti-HCV was significantly higher than that of HBsAg (2.25 cf 0.86 percent among males, P < 0.001; 2.17 cf 0.55 percent among females, P < 0.001. It was much higher in the blood donors aged 55-64 years than in those aged 16-54 years (8.49 cf 1.32 percent among males, P < 10(-5); 7.26 cf 1.42 percent among females, P < 10(-5)). The prevalence of anti-HCV among males was significantly higher than that of females in the younger (25-34 years) generations (1.02 to 1.49 percent cf 0.71 to 1.13 percent, P < 0.05). A similar tendency was observed in the prevalence of high-titer (> or = 2(12)) anti-HCV. The number of coinfection (both HBsAg and anti-HCV seropositive) was very small, and it was not statistically different from the expected number.

Cumulative risk of hepatocellular carcinoma in hepatitis C virus carriers: statistical estimations from cross-sectional data

The probability of developing hepatocellular carcinoma (HCC) among hepatitis C virus (HCV) carriers during their life-time is unknown. This paper addresses the estimation of the cumulative risk of HCC among HCV carriers using cross-sectional data. Age-specific prevalences of HCV carriers among the general population were estimated according to 5-year age group, based on the data of 2nd-generation anti-HCV assay in blood donors resident in Osaka (33,226 males and 29,054 females). Seropositivity of anti-HCV among 422 HCC cases, and the Osaka Cancer Registry data on HCC were used in the estimations of 5-year age-specific incidence rates of HCV-linked HCC. Using these data, the cumulative risk, i.e., the probability of contracting HCC within the following 15 years in 50-year-old HCV carriers, was estimated as 28% for males and 6% for females.

Negative regulation of mitosis by the fission yeast protein phosphatase ppa2

To understand the role of the type 2A-like protein phosphatase in the cell division cycle, we investigated the mutant phenotypes obtained when the fission yeast ppa1+ and ppa2+ phosphatase genes (which encode polypeptides with approximately 80% identity to mammalian type 2A phosphatases) were either deleted or overexpressed. We also investigated the in vivo effect of okadaic acid, an inhibitor of protein serine/threonine phosphatases, on cell division. We show that ppa2+ interacts genetically with the cell cell regulators cdc25+ and wee1+, as a ppa2 deletion is lethal when combined with wee1-50 but partially suppresses the conditional lethality of cdc25-22 mutation. Evidence that ppa2+ negatively controls the entry into mitosis, possibly through the regulation of cdc2 tyrosine phosphorylation, is presented. ppa2 phosphatase is abundant in the cytoplasm, in contrast to the type 1-like phosphatase dis2, which is enriched in the nucleus. Overproduced ppa1 or ppa2 proteins accumulate in the cytoplasm near the nuclear periphery, and cells arrest in interphase. Okadaic acid-treated cells, like a ppa2 deletion, are short in length and display protein hyperphosphorylation. Cytokinesis is also inhibited, producing binucleated cells. We show that ppa2 is the genetic locus controlling okadaic acid sensitivity. The ppa2 deletion reveals the same hyperphosphorylated proteins as okadaic acid. When a strain deleted for ppa2 is treated with okadaic acid, cell size is reduced further to that of wee1-50 mutant strain or overexpressing the cdc25+ gene product, suggesting functional relationship of ppa2 with the cdc25 tyrosine phosphatase and/or the wee1 kinase in cell cycle control.

Mitotic regulation of protein phosphatases by the fission yeast sds22 protein

BACKGROUND

Cell cycle progression requires the activity of protein kinases and phosphatases at critical points in the cell cycle in all eukaryotes. We have previously reported that the dis2(+) and sds2(+) genes of fission yeast encode redundant catalytic subunits of a type 1-like protein phosphatase. The sds22(+) gene was shown to be essential for cell viability and to interact genetically with dis2(+) and sds21(+).

RESULTS

Here we show by immunoprecipitation that the sds22 protein physically interacts with the dis2 and sds21 proteins, and that sds22-associated phosphatase activity has altered substrate specificity, The loss of sds22 function by a temperature sensitive mutation leads to cell cycle arrest at mid-mitosis, at which point cdc2-dependent histone Hl kinase activity is high while sds22-dependent H1 phosphatase activity is low. To examine the unusual properties of sds22 protein structure, we analyzed a collection of sds22 deletion and point mutants by a variety of functional criteria.

CONCLUSION

We propose that sds22 is a regulatory subunit of the dis2/sds21 phosphatase catalytic subunits and that sds22-bound phosphatase carries a key phosphatase activity essential for the progression from metaphase to anaphase. Mutational analysis indicates that dis2/sds21 interacts with the central repetitive domain of sds22, while the C-terminal and central regions of sds22 may be involved in subcellular targeting and the N-terminus is important for stability.

Fission yeast pap1-dependent transcription is negatively regulated by an essential nuclear protein, crm1

The fission yeast pap1+ gene encodes an AP-1-like transcription factor that contains a leucine zipper motif. We identified a target gene of pap1, the p25 gene. The 5' upstream region of the p25 gene contains an AP-1 site, and by DNase I footprint analysis, we showed that the pap1 protein binds to the AP-1 site as well as to a 14-bp palindrome sequence. p25 is overproduced when the pap1+ gene is overexpressed, whereas p25 is not produced at all in the pap1 deletion mutant. p25 was previously found to be overproduced in strains carrying cold-sensitive crm1 mutations whose gene product is essential for viability and is thought to play an important role in maintenance of a proper chromosomal architecture. Deletion and site-directed mutagenesis of sequences upstream of the p25 gene demonstrated that the AP-1 site as well as the palindrome sequence are crucial for transcriptional activation either by pap1 overproduction or by the cold-sensitive crm1 mutation; pap1+ is apparently negatively regulated by crm1+. Moreover, we found that cold-sensitive crm1 mutations are suppressed by the deletion of pap1+, further indicating a close relationship between crm1+ and pap1+. The crm1 protein is highly conserved; the budding yeast homolog, CRM1, which complements the fission yeast cold-sensitive crm1 mutation, was isolated and found to also be essential for viability. These results suggest the functional importance of chromosome structure on the regulation of gene expression through the pap1 transcription factor.

Study on the interaction between soybean beta-amylase and substrate by the stopped-flow method

The hydrolysis of substrates (maltoheptaose, maltopentaose, and maltotetraose) catalyzed by soybean beta-amylase [EC 3.2.1.2] at pH 5.4 and 25 degrees C was followed by monitoring small changes in the quenching of fluorescence due to tryptophan residues by the stopped-flow method. By analysis of whole time course, the dissociation constants, KdS, of enzyme-substrate and enzyme-product complexes were reasonably evaluated; and the difference in fluorescence intensities per mol between the enzyme-complex (ES or EP) and the free enzyme, delta F, was determined. The molecular activity, k0, was also determined by a new method of half time analysis. The KdS and k0 values are in good agreement with our kinetic data reported previously. The delta Fs of substrates were of smaller magnitude than those of products (G2 and G3), which means that the higher the binding affinity of the ligand is, the smaller the delta F value is. This indicates that at least two tryptophan residues must be located in the active site if the enzyme is rigid, or that if there is only one, the active site must undergo a structural change caused by the binding of ligand.

Gene cloning of Porphyromonas gingivalis specific antigens recognized by serum of adult periodontitis patient

1. Porphyromonas gingivalis is believed an important pathogen of adult periodontitis. A gene library of P. gingivalis 381 was constructed in lambda phage vector L47.1. The library was probed with serum obtained from patients of severe adult periodontitis. Two clones, lambda MDBG101 and lambda MDBG103 which were expressed, 200 and 160 kDa respectively, were selected and further studied. 2. The expressed antigens in these two clones were also reacted with rabbit antiserum against whole cells, capsular fraction and cell surface fraction of P. gingivalis. 3. Genes coding protein antigens in lambda MDBG101 and lambda MDBG103 were subcloned into high-copy-number plasmid vector pACYC184 and subclones obtained were designated as MD101 and MD103. Recombinant plasmids, pMD101 and pMD103, differed in their restriction endonuclease digestion. 4. Immunodiffusion analysis showed that cloned proteins from MD101 and MD103 reacted with antiserum against P. gingivalis but did not react with antiserum against Prevotella intermedia, Prevotella loescheii and Prevotella asaccharolyticus. 5. These data suggest that P. gingivalis species-specific antigens has been successfully cloned and expressed in Escherichia coli. Since these cloned specific antigens were recognized by adult periodontitis patient sera, the recombinant antigen will be useful material for the development of serodiagnosis of P. gingivalis infection in adults periodontitis.

Transcriptional terminator is a positive regulatory element in the expression of the Escherichia coli crp gene

Plasmids were constructed that contain deletions in the stem region of the presumed rho-independent terminator of the cloned crp gene of Escherichia coli. The level of cyclic AMP binding activity and the amount of CRP in cells harboring the deletion plasmids were found to be significantly lower than those in cells harboring the wild-type crp plasmid. Quantitative S1 assays indicated that the steady-state levels of crp mRNA were markedly reduced in cells harboring the deletion plasmids. Evidence was also presented to show that the crp mRNAs produced from deletion plasmids are less stable than that from the intact crp gene. In vitro transcription assays revealed that the putative crp terminator is indeed a rho-independent terminator. Using the galK expression system and Northern blot analysis we showed that the crp terminator is functional in vivo. Moreover it was shown that the deletion mutations in the stem region of the crp terminator cause a significant readthrough. We conclude that the 3'-flanking sequence of the crp gene acts to stabilize its own mRNA as well as to terminate transcription.

[Study for improvement of oral health among the elderly. Present status of dental care service at elderly homes]

Since the dental environment at a living place could potentially become a factor causing a need for dental care, all 33 elderly homes (27 of which responded to the survey) in Tokyo were investigated for the purpose of identifying the present status of dental care service and the problems existing at these homes. The following are the obtained conclusions. 1. The rate of homes with dental care facilities is as low as 19.2%, and cooperation by dental care institutions, including house calls, is ensured only at the low rate of 11.1%. As a result, usually patients visit the dental institutions. 2. The involvement of the dental staff, including part-time, was 44.4%, less than half of the homes surveyed. The homes wishing to employ or receive service from dental staff accounted for 76.9%. The homes also expected them to be engaged in the activities of overall oral hygiene, including not only dental treatment, but also participation in the planning of oral hygienic management. However, 23.1% of the respondents did not wish to employ any dental staff or receive any such service. 3. Specific programs for the guidance and management of oral hygiene were not observed. Homes that conducted dental examination periodically and those that carried out activities related to oral hygiene during Dental Health Week were also lacking. In addition, the homes which had assigned personnel responsibility for oral hygiene represented only 12.0%.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of maternal caffeine with zinc intake during gestation and lactation on bone development in newborn rats

On day 9 of gestation, pregnant dams were randomly divided into 3 groups. Dams of group 1 were fed a 20% protein diet as a control. Dams of group 2 were fed a 20% protein diet supplemented with caffeine. Dams of group 3 were fed a 20% protein diet supplemented with caffeine and zinc. The amount of caffeine added to the maternal diet was 2 mg/100 g body weight; the amount of zinc was 0.6 g/kg of diet. At birth, pups were mixed within each group, and 8 randomly selected pups from each group were assigned to each dam of the respective group and were continuously fed the same diet. On day 15, the pups were killed and cranial bones, mandibles and femurs removed. The bones were measured, and the mineral content of the mandibles and femurs was determined. Although there were no differences in the dimensions of the cranial bones among the groups, the measurements and mineral content of the mandibles and femurs were consistently affected by the caffeine in the diet. On the other hand, supplementation of the caffeine-added diets with zinc led to greatly improved bone development, reaching values up to or beyond control levels. Thus zinc supplementation of a caffeine diet given to the dams during gestation and lactation can favourably influence the otherwise impaired bone development of their offspring.

Time trends of the prevalences of hepatitis B e antigen positives among hepatitis B virus carriers in Japan

In order to examine time trends of the prevalences of HBeAg positives among HBV carriers in Japan, we analysed data on HBeAg of HBsAg positive voluntary blood donors (23,560 males, and 8659 females) at the Osaka Red Cross Blood Centre between January 1977 and March 1984. Age-specific prevalences of HBeAg positives decreased year by year for both sexes, especially for those in their teens and twenties. The prevalences of HBeAg positives decreased with age, but at any given age it was lower for the later than for the earlier birth cohorts. Although reasons for the secular declines are unknown, the findings suggest that the prevalence of HBeAg positives among HBV carriers will continue to decrease in Japan. This, together with the immunization programme implemented this year, may lead to a future reduction in the risk of HBV related liver diseases in Japan.