Microbial mat compositions and localization patterns explain the virulence of black band disease in corals.

Black band disease (BBD) in corals is characterized by a distinctive, band-like microbial mat, which spreads across the tissues and often kills infected colonies. The microbial mat is dominated by cyanobacteria but also commonly contains sulfide-oxidizing bacteria (SOB), sulfate-reducing bacteria (SRB), and other microbes. The migration rate in BBD varies across different environmental conditions, including temperature, light, and pH. However, whether variations in the migration rates reflect differences in the microbial consortium within the BBD mat remains unknown. Here, we show that the micro-scale surface structure, bacterial composition, and spatial distribution differed across BBD lesions with different migration rates. The migration rate was positively correlated with the relative abundance of potential SOBs belonging to Arcobacteraceae localized in the middle layer within the mat and negatively correlated with the relative abundance of other potential SOBs belonging to Rhodobacteraceae. Our study highlights the microbial composition in BBD as an important determinant of virulence.

Development of an analytical chip for colorimetric detection of medium-chain aldehydes by reaction with pararosaniline in porous glass.

Medium-chain aldehydes are common human biogases that can be detected in the breath of patients with lung diseases. As such, the measurement of medium-chain aldehyde gases in human breath can provide significant, noninvasive, and diagnostic information related to the potential presence of such diseases. In this study, an analytical chip is developed for the detection of medium-chain aldehydes without interference from short-chain aldehydes. This analytical chip is composed of porous glass impregnated with pararosaniline and an acid (i.e., acetic acid with small amount of phosphoric acid). After exposure to medium-chain aldehydes, the red analytical chip became violet in color, and an absorption peak was observed at 620 nm. It was found that a non-reversible reaction occurred in the porous glass, therefore, the analytical chip functions in a cumulative manner. A linear relationship was determined between the absorbance change of the analytical chip at 620 nm and the nonanal exposure concentration. Importantly, the developed analytical chip successfully detected nonanal at concentrations of 8-270 ppb as calculated from the absorbance change at 620 nm after a 24 h exposure time. In addition, nonanal concentration was estimated using the change in the R value of the analytical chip photograph. This method is suitable for point-of-care breath analysis. Finally, the analytical chip was also found to be active toward octanal and decanal with a relative sensitivity of 0.7 compared to that of nonanal; it was not active toward short-chain aldehydes.

Changes in spike protein antibody titer over 90 days after the second dose of SARS-CoV-2 vaccine in Japanese dialysis patients.

OBJECTIVES: There is no report on antibody titers after vaccination against SARS-CoV-2 in Japanese dialysis patients. As dialysis is different between Japan and other countries, changes in antibody titers were examined. METHODS: Baseline characteristics and anti-spike protein antibody titers (Roche) over 90 days after administration of the BNT162b2 messenger RNA vaccine were investigated in dialysis patients. RESULTS: The maximum anti-spike protein antibody titer after the second dose was 738 (327 to 1143) U/mL and was reached at 19 (17 to 24) days after the second dose. Antibody titers decreased over time, with titers of 770 (316 to 1089) U/mL at 15 days, 385 (203 to 690) U/mL at 30 days, 254 (138 to 423) U/mL at 60 days, and 208 (107 to 375) U/mL at 90 days after the second dose. When an antibody titer of 137 U/mL was assumed to be a measure related to breakthrough infection, the proportion of subjects with antibody titers exceeding this level was 90.1% at 15 days, 85.3% at 30 days, 75.0% at 60 days, and 65.4% at 90 days after the second dose. When a decrease in antibody titers below the assumed breakthrough level was defined as an event, subjects with a pre-dialysis albumin ≥ 3.5 g/dL were significantly less likely to experience an event than subjects with a pre-dialysis albumin < 3.5 g/dL. CONCLUSIONS: The presence of anti-spike protein levels ≥ 313 U/mL at 30 days after the second vaccine dose might be a factor in maintaining enough antibody titers at 90 days after. Whether an additional vaccine dose is needed should be determined based on indicators serving as factors in maintaining antibody titers as well as the status of the spread of infection.

Distribution of transglutaminase family members in mouse whole body sections.

Transglutaminases (TGs) comprise a protein family in which the members catalyze the formation of isopeptide bonds between glutamine and lysine residues in various proteins. Eight enzymes have been identified and designated as factor XIII (FXIII) and TG1-7. Expression studies of four major members, i.e., FXIII, TG1, TG2, and TG3, have been performed in a relatively large number of mammalian tissues in comparison with those on the other isozymes. The structural and biochemical characteristics of these individual isozymes and expression analyses of TG family in some tissue extracts have been reported, but there have been no simultaneous comparative analyses of both their mRNA and protein expression patterns in tissues distributions. Thus, we developed novel experimental systems for in situ hybridization using cryofilm attached to whole body sections of neonatal mice, thereby obtaining data regarding the tissue distributions of the major TG isozymes. In this study, we performed the first detailed comparative analysis of the mRNA and protein distribution studies of TG family members in a wide range of mouse tissues. These data will be helpful for elucidating the unknown physiological and pathological functions of TGs.

Roles of GIG1 and UVI4 in genome duplication in Arabidopsis thaliana.

Endomitosis and endoreplication are atypical modes of cell cycle that results in genome duplication in single nucleus. Because the cell size of given cell type is generally proportional to the nuclear DNA content, endoreplication and endomitosis are effective strategy of cell growth, which are widespread in multicellular organisms, especially those in plant kingdom. We found that these processes might be differently regulated by GIGAS CELL1 (GIG1) and its paralog UV-INSENSITIVE4 (UVI4) in Arabidopsis thaliana. GIG1 and UVI4 may negatively regulate activities of anaphase-promoting complex or cyclosome (APC/C) ubiquitin ligase that acts as an important mitotic regulator. The gig1 mutation induced ectopic occurrence of endomitosis during somatic cell division, while it has been reported that uvi4 mutation resulted in premature occurrence of endoreplication during organ development. Overexpression of GIG1 and UVI4 dramatically increased the amount of mitotic cyclin, CYCB1;1, a well-known substrate of APC/C. Ectopic endomitosis in gig1 was enhanced by mutation in CYCB2;2 and suppressed by downregulation of APC10 encoding a core subunit of APC/C. Overexpression of CDC20.1, an activator protein of APC/C, further promoted the ectopic endomitosis in gig1. These findings suggest that endomitosis and endoreplication are regulated by similar molecular mechanisms, in which two related proteins, GIG1 and UVI4, may inhibit APC/C in different ways.

Three cases of acute or fulminant hepatitis E caused by ingestion of pork meat and entrails in Hokkaido, Japan: Zoonotic food-borne transmission of hepatitis E virus and public health concerns.

AIM: In developed countries including Japan, the transmission route of indigenous hepatitis E virus (HEV) infection is obscure. Accordingly, public health implications of indigenous HEV infection have not been well addressed. The aim of this study was to clarify the route of transmission of a small outbreak of acute hepatitis E and assess the public health implications of indigenous zoonotic HEV transmission. METHODS: Three patients with non-A, B and C acute hepatitis, two of whom presented in a critical condition, were assessed for HEV infection using polymerase chain reaction and their route of infection; the genome sequences of the infecting HEV were also analyzed. A phylogenetic tree based on the full, or near full, HEV RNA sequences were constructed by neighbor-joining method. RESULTS: All three patients ingested grilled pork meat and entrails at the same barbecue restaurant in Abashiri, Hokkaido, Japan. When comparing partial to entire, or nearly entire, nucleotide sequences of HEV detected in these patients, they were 99.9-100% identical to each other. These genotype 4 isolates had great resemblance to the genome sequences of the isolates from the mini-outbreak in 2004 in Kitami, a city adjacent to Abashiri. These Kitami/Abashiri strains were segregated into a single cluster on the phylogenetic tree of HEV genotype 4 indigenous to Japan. CONCLUSION: Indigenous HEV transmission via a zoonotic food-borne route has been demonstrated in Kitami and Abashiri via pork meat and entrails contaminated with virulent HEV strains. Because a similar outbreak can recur in the future, infection sources and distribution routes should be clarified rapidly for public health.

Notch ligands transduce different magnitudes of signaling critical for determination of T-cell fate.

Notch signaling mediated by Delta-like (Dll) 4 is essential and sufficient for T-cell development in vivo. Stromal cells expressing Dll4 or Dll1, but not Jagged1, support T lymphopoiesis in vitro, but the molecular basis of this functional divergence among Notch ligands remains to be clarified. To examine this, we constructed chimeric variants composed of Dll4 and Jagged1. The intracellular regions were necessary, but interchangeable, for signal induction, and the extracellular regions determined the unique characteristics of the ligands. While Jagged1 induced minimal Notch signaling, Jagged2 elicited substantial levels of Hes1 transcripts and promoted T lymphopoiesis in vitro. Dll4 and Jagged2 showed a quantitative advantage when bound to fringe-modified Notch; this was not due to the Delta-Serrate-Lag2 domain, an extracellular region essential for interaction with Notch. These results suggest that different Notch ligands possess distinct potentials for the induction of Notch signaling through unique interactions of their extracellular regions with fringe-modified Notch. Furthermore, the magnitude of Notch signaling induced is critical for the determination of T-cell fate.

Virulent strain of hepatitis E virus genotype 3, Japan.

Hepatitis E virus (HEV) genotype 3, which usually causes asymptomatic infection in Japan, induced severe hepatitis in 8 patients. To better understand genetic features of HEV associated with increased virulence, we determined the complete or near-complete nucleotide sequences of HEV from these 8 patients and from 5 swine infected with genotype 3 strain swJ19. Phylogenetic analysis showed that the isolates from the 8 patients and the 5 swine grouped separately from the other genotype 3 isolates to create a unique cluster, designated JIO. The human JIO-related viruses encoded 18 amino acids different from those of the other HEV genotype 3 strains. One substitution common to almost all human HEV strains in the JIO cluster was located in the helicase domain (V239A) and may be associated with increased virulence. A zoonotic origin of JIO-related viruses is suspected because the isolates from the 5 swine also possessed the signature V239A substitution in helicase.

Notch signaling is necessary for GATA3 function in the initiation of T cell development.

GATA3 and Notch1 are essential for T cell development at the earliest stage, but their mutual roles in this process remain to be clarified. In this study, we demonstrated that impairment of T lymphopoiesis in hematopoietic progenitor cells (HPC) of GATA3-deficient fetal liver (FL) on day 11.5 of gestation (E11.5) was rescued only by introduction of both GATA3 and the intracellular region of Notch1 but not by either alone. However, the introduction of GATA3 only was sufficient for T cell induction in GATA3-deficient FL cells at the advanced stage, where Notch signaling is well detectable. This indicates that Notch signaling is necessary for GATA3 to function for T cell fate specification but is not sufficient without GATA3. On the other hand, Notch signaling is sufficient for blockage of B cell development without GATA3, suggesting that T cell fate specification at the branching point does not result simply from the developmental arrest of B cell lineage by Notch signaling.

Prevalence of hepatitis E virus IgG antibody in Japanese patients with hemophilia.

OBJECTIVE: We investigated the prevalence of antibody against hepatitis E virus (HEV) in Japanese patients with hemophilia. METHODS: IgG antibody against HEV was measured in serum of 80 Japanese patients with hemophilia by enzyme-linked immunosorbent assay. The prevalence of HEV antibody was compared with the reported prevalence of HEV antibody in Japanese patients undergoing hemodialysis and in Japanese healthy blood donors. Characteristics of patients and coinfection with other transfusion-transmissible viruses were compared in patients with and without HEV antibody. RESULTS: Anti-HEV IgG antibody was detected in 13 of 80 patients (16.3%). The prevalence was far higher than that reported in Japanese blood donors (3.7%) and was higher than that in Japanese patients undergoing hemodialysis (9.4%). The patients with HEV antibody were significantly older than those without. HEV antibody was not detected in patients <20 years of age and in patients who had received only virus-inactivated coagulation factors. No association was observed between positivity for anti-HEV antibody and severity of hemophilia or coinfection with other parenterally transmissible viruses. CONCLUSION: Our results suggest that the parenteral transmission of HEV may have occurred in Japanese patients with hemophilia via non-virus-inactivated coagulation factors.

Prevalence of hepatitis E virus among wild boar in the Ehime area of western Japan.

AIMS: Transmission of hepatitis E virus (HEV) from wild boar to humans has been reported, particularly from Japan. We attempted to clarify this issue. METHODS: We assessed the IgG class antibodies against HEV (anti-HEV) in serum samples taken from 406 boar living in the Ehime area of western Japan from 2001 to 2004, of which 392 were captured in the wild (wild-caught boar) and 14 had been kept in a breeding farm (bred boar). RESULTS: Anti-HEV positive rate in the bred boar (10/14, 71.4%) was significantly higher than in the wild-caught boar (100/392, 25.5%) (P < 0.001). Of the 392 wild-caught boar, 12 (3.1%) were positive for HEV-RNA, 10 of which were then subjected to phylogenetic analyses by sequencing an 821-nt fragment within ORF1. All the 10 isolates segregated to genotype 3, and eight of them were mutually related to form a cluster. All the eight HEV isolates in this cluster were from the wild-caught boar living in one and the same habitat within the studied area, while the other two independent isolates were from different regions. CONCLUSION: HEV infection is endemic in wild boar in the Ehime area, and we should regard the wild boar as an important reservoir of HEV.

Epidemiology of hepatitis B, C, and E viruses and human immunodeficiency virus infections in Tahuna, Sangihe-Talaud Archipelago, Indonesia.

BACKGROUND/AIMS: The epidemiology of hepatitis B, C,E viruses (HBV, HCV, HEV) and human immunodeficiency virus(HIV) has been obscure in Indonesia, particularly remote areas. METHODS: We undertook serological surveys for HBV/HCV/HEV/HIV infections in the general population of Tahuna, the capital city of Sangihe-Talaud Archipelago,outlier in the northeastern part of Indonesia. RESULTS: Of 581 sera collected in April 2005, 1.4% was reactive for HBsAg,0.2% for anti-HCV, and 5.9% for anti-HEV, but none for HIV. All the HBsAg-positive sera were also positive for DNA, the nucleotide sequence of which is segregated within subgenotype C5. Most of the preschool children were positive for anti-HBs as a result of an HB immunization initiated in 1997. The titer of anti-HCV in the only individual detected was very low, with a negative result of HCV RNA detection,suggesting a nonspecific reaction. Anti-HEV was significantly more frequent in those over 30 years of age than in the younger age group (24 vs. 1.9%, p ! 0.0001). CONCLUSION: Thus, it seems that HCV and HIV have fortunately not made it as far as the Sangihe-Talaud Archipelago. Although HBV infection remains a major problem in adults (with the HBsAg-positive rate at 4.9%), HB immunization has begun to protect the younger generation.

Reduction of Runx1 transcription factor activity up-regulates Fas and Bim expression and enhances the apoptotic sensitivity of double positive thymocytes.

The death or survival of double positive (DP) thymocytes is determined by the strength of their TCR signaling. Of the three Runx family proteins, the DP cells only express the Runx1 transcription factor. We introduced and expressed in murine thymocytes the Runt domain of Runx1, which antagonizes the activity of endogenous Runx1. The Runt transgenic DP thymocytes expressed higher levels of the proapoptotic molecules Fas and Bim compared with the wild-type cells. Furthermore, the Runt transgenic cells were more susceptible to apoptosis induced by the artificial cross-linking of the TCR by the anti-CD3 Ab. This susceptibility was partially abrogated by the lpr/lpr background. In addition, Runx1:HY-TCR-double transgenic DP thymocytes were resistant to the apoptosis induced by the endogenously presented HY Ag. We propose that Runx1 functions to suppress the apoptotic sensitivity of DP thymocytes in the context of TCR signaling.

Overexpression of the Runx3 transcription factor increases the proportion of mature thymocytes of the CD8 single-positive lineage.

The Runx family of transcription factors is thought to regulate the differentiation of thymocytes. Runx3 protein is detected mainly in the CD4(-)8(+) subset of T lymphocytes. In the thymus of Runx3-deficient mice, CD4 expression is de-repressed and CD4(-)8(+) thymocytes do not develop. This clearly implicates Runx3 in CD4 silencing, but does not necessarily prove its role in the differentiation of CD4(-)8(+) thymocytes per se. In the present study, we created transgenic mice that overexpress Runx3 and analyzed the development of thymocytes in these animals. In the Runx3-transgenic thymus, the number of CD4(-)8(+) cells was greatly increased, whereas the numbers of CD4(+)8(+) and CD4(+)8(-) cells were reduced. The CD4(-)8(+) transgenic thymocytes contained mature cells with a TCR(high)HSA(low) phenotype. These cells were released from the thymus and contributed to the elevated level of CD4(-)8(+) cells relative to CD4(+)8(-) cells in the spleen. Runx3 overexpression also increased the number of mature CD4(-)8(+) thymocytes in mice with class II-restricted, transgenic TCR and in mice with a class I-deficient background, both of which are favorable for CD4(+)8(-) lineage selection. Thus, Runx3 can drive thymocytes to select the CD4(-)8(+) lineage. This activity is likely to be due to more than a simple silencing of CD4 gene expression.

Complete or near-complete nucleotide sequences of hepatitis E virus genome recovered from a wild boar, a deer, and four patients who ate the deer.

Zoonosis has been implicated in hepatitis E virus (HEV) transmission. We examined wild boar living in a forest of Hyogo prefecture, Japan, and found HEV RNA in three of seven boars. A full-genome HEV isolate from one of them was revealed to be 99.7% identical to a previous isolate from a wild deer hunted in the same forest and to those from four patients who contracted hepatitis E after eating raw meat of the deer. These findings suggest an interspecies HEV transmission between boar and deer in their wild life, and that both animals might serve as an infection source for human beings as suggested previously.

Estimation of the mutation rate of hepatitis E virus based on a set of closely related 7.5-year-apart isolates from Sapporo, Japan.

Since hepatitis E virus (HEV) does not persist in infected hosts or in cultured cell lines, it has been difficult to know its spontaneous mutation rate. Recently, we identified an HEV isolate in stored serum from a patient having developed hepatitis E in 1995 (JSM-Sap95), nucleotide sequence of which showed a strong resemblance to those obtained from three patients who contracted hepatitis E in 2000 and 2002 (JKK-Sap00, JYW-Sap02, and JTS-Sap02). The remarkable nucleotide similarity together with the fact that all these patients were residents of the same city, Sapporo, prompted us to hypothesize that JKK-Sap00, JYW-Sap02 and JTS-Sap02 are descendants of JSM-Sap95. Then, the mutation rate of HEV was calculated to be 1.72, 1.41, or [Formula: see text] base substitutions per site per year, from JSM-Sap95 to JKK-Sap00, JYW-Sap02 or JTS-Sap02, respectively. Interestingly, these values were very similar to those ( [Formula: see text] to [Formula: see text] ) reported for hepatitis C virus. Because it remains possible that JSM-Sap95 is not the direct ancestor of the other three isolates but was merely a relative of the true ancestor, HEV mutation rate may be a little lower than [Formula: see text] base substitutions per site per year.

Delta-like 1 is necessary for the generation of marginal zone B cells but not T cells in vivo.

Notch receptors and their ligands contribute to many developmental systems, but it is not apparent how they function after birth, as their null mutants develop severe defects during embryogenesis. Here we used the Cre-loxP system to delete the Delta-like 1 gene (Dll1) after birth and demonstrated the complete disappearance of splenic marginal zone B cells in Dll1-null mice. In contrast, T cell development was unaffected. These results demonstrated that Dll1 was dispensable as a ligand for Notch1 at the branch point of T cell-B cell development but was essential for the generation of marginal zone B cells. Thus, Notch signaling is essential for lymphocyte development in vivo, but there is a redundancy of Notch-Notch ligand signaling that can drive T cell development within the thymus.

Active form of Notch members can enforce T lymphopoiesis on lymphoid progenitors in the monolayer culture specific for B cell development.

The in vitro induction of T lymphopoiesis needs the precise stereoscopic structure of thymus tissues as seen in fetal thymus organ culture. In this study, we demonstrated for the first time that the introduction of the intracellular region of Notch1 can induce T cells expressing TCR without any thymic environment. In the coculture on the monolayer of OP-9, which was originally known to support B cell specific development, hemopoietic progenitors developed into Thy-1(+)CD25(+) T lineage cells if the progenitor cells were infected with the retrovirus containing Notch1 intracellular domains. The Thy-1(+) cells progressed to a further developmental stage, CD4 and CD8 double-positive cells expressing TCR on the cell surface, if they were further cultured on OP-9 or in the thymus. However, T cell induction by intracellular Notch1 failed unless both OP-9 and IL-7 were present. It is notable that Notch2 and Notch3 showed an effect on T lymphopoiesis similar to that of Notch1. These results indicate that in vitro T lymphopoiesis is inducible by signaling via Notch family members in a lineage-specific manner but shares other stroma-derived factors including IL-7 with B lymphopoiesis.