Fumiaki Taguchi

Prevalence Rate and Age of Acquisition of Antibodies against JC Virus and BK Virus in Human Sera

A total of 480 serum samples from donors including 384 children up to 10 years of age were examined by the hemagglutination‐inhibition (HI) test for the rates of prevalence and age of acquisition of HI antibodies against JC virus and BK virus. Among 136 serum samples from various age groups, there were five (4%) with no detectable antibodies against BK or JC virus, 75 (55%) with antibodies against both viruses, 41 (30.1%) with antibodies against only BK virus and 26 (19%) with antibodies against only JC virus. The prevalence of antibodies against JC and BK viruses was 70.5% and 80.8%, respectively, and the mean HI titers (4 × 2n, n≥1) were 4.90 and 4.30. About 50% of the children had acquired antibodies against BK virus by 3 years of age and against JC virus by 6 years of age. These results indicate that dual latent infections with both viruses are common, although independent infections with either virus are predominant in the human population.

Continuous hydrogen production by Clostridium sp. strain no. 2 from cellulose hydrolysate in an aqueous two-phase system☆

Abstract Continuous hydrogen production by fermentation of Avicel hydrolysate in an aqueous two-phase system, using Clostridium sp. strain no. 2, was investigated. Continuous hydrolysis of Avicel with a commercial cellulase preparation was performed in an aqueous two-phase system consisting of 10% polyethylene glycol and 5% dextran. The hydrolysate was continuously pumped at a dilution rate of 0.17 h−1 into a 300-ml hydrogen fermentor. During an 81-h period of stationary culture, strain no. 2 consumed 0.92 mmol·h−1 glucose and produced 4.10 mmol·h−1 hydrogen.

Evolution of Human Polyomavirus JC: Implications for the Population History of Humans

The polyomavirus JC virus (JCV), the etiological agent of progressive multifocal leukoencephalopathy, is ubiquitous in the human population, infecting children asymptomatically, then persisting in the kidney. The main mode of transmission of JCV is from parents to children through long-term cohabitation. Twelve JCV subtypes that occupy unique domains in Europe, Africa, and Asia have been identified. Here, we attempted to elucidate the evolutionary relationships among JCV strains worldwide using the whole-genome approach with which a highly reliable phylogeny of JCV strains can be reconstructed. Sixty-five complete JCV DNA sequences, derived from various geographical regions and belonging to 11 of the 12 known subtypes, were subjected to phylogenetic analysis using three independent methods: the neighbor-joining, maximum parsimony, and maximum likelihood methods. The trees obtained with these methods consistently indicated that ancestral JCVs were divided into three superclusters, designated as Types A, B, and C. A split in Type A generated two subtypes, EU-a and -b, mainly containing European and Mediterranean strains. The first split in Type B generated Af2 (the major African subtype). Subsequent splits in Type B generated B1-c (a minor European subtype) and all seven Asian subtypes (B1-a, -b, -d, B2, MY, CY, and SC). Type C generated a single subtype (Af1), consisting of strains derived from western Africa. While the present findings provided a basis on which to classify JCV into types or subtypes, they have several implications for the divergence and migration of human populations.

Efficient hydrogen production from starch by a bacterium isolated from termites

Abstract Clostridium beijerinckii AM21B strain was isolated from termites. AM21B respectively converted 10 g of glucose or starch to 2,450 ml or 2,255 ml of H 2 , while the maximum evolution rate was 660 ml or 410 ml of H 2 per hour, respectively from 1 l of PY medium containing 10 g of glucose or starch, at pH 6.5. This H 2 production from starch by a non-photosynthetic bacterium appears to be the first report known to the authors.

Geographical distribution of the human polyomavirus JC virus types A and B and isolation of a new type from Ghana

The JC polyomavirus (JCV) is ubiquitous in humans infecting children asymptomatically, then persisting in renal tissue. Since JCV DNA can be readily isolated from urine, it should be a useful tool with which to study the evolution of DNA viruses in humans. We showed that JCV DNA from the urine of Japanese, Taiwanese, Dutch and German patients can be classified into A and B types, based upon restriction fragment length polymorphisms (RFLPs). This work was extended in the present study. We established multiple JCV DNA clones from the UK, Spain, Italy, Sweden, South Korea, Peoples Republic of China, Malaysia, Indonesia, Mongolia, India, Sri Lanka, Saudi Arabia, Ethiopia, Kenya, Zambia, South Africa and Ghana. Using type-specific RFLPs, most clones except the four clones from Ghana were classified as either type A or B. We constructed a molecular phylogenetic tree for the Ghanaian clones and several representative type A and B clones. According to the phylogenetic tree, the Ghanaian clones constituted a major new group, tentatively named type C. From the findings presented here and elsewhere, the following conclusions were drawn: (i) type A is prevalent only in Europe; (ii) type B is found mainly in Asia and Africa; and (iii) type C is localized to part of Africa. Our findings should help to clarify how JCV evolved in humans.

Four geographically distinct genotypes of JC virus are prevalent in China and Mongolia: implications for the racial composition of modern China

JC polyomavirus (JCV) is ubiquitous in humans, persisting in renal tissue and excreting progeny in urine. It has been shown that the genotyping of urinary JCV offers a novel means of tracing human migrations. This approach was used to elucidate the racial composition of modern China. JCV isolates in the Old World were previously classified into nine distinct genotypes. One of them (B1) has a wide domain, encompassing part of Europe and the entirety of Asia. By constructing a neighbour-joining phylogenetic tree, all B1 isolates detected so far were classified into four distinct groups (B1-a to -d), each occupying unique domains in the world. According to this revised classification system of JCV DNAs, four genotypes (CY, SC, B1-a and -b) were found to be prevalent in China and Mongolia (Mongolia was studied instead of Inner Mongolia, which is part of China). There was a remarkable variation in the incidence of genotypes among the sites of sample collection. CY was more frequently detected in Northern China, SC was predominant in Southern China and B1-b was detected only in Mongolia. B1-a was spread throughout China. These data were statistically analysed and the observed regional differences in the incidence of genotypes were found to be significant. It is likely that these differences in JCV distribution in China reflect the intermingling of different population groups that constitute modern China.

Proposal for a procedure for complete inactivation of the Creutzfeldt-Jakob disease agent

We have examined complete inactivation conditions on brain homogenates from mice affected with Creutzfeldt-Jakob disease agent, and recommend for routine use a reliable procedure first treating the affected materials with 1 N NaOH for 60 min and then autoclaving at 121 degrees C for 30 min.

Direct conversion of cellulosic materials to hydrogen by Clostridium sp. strain no. 2

We investigated hydrogen production by fermentation of enzymatic hydrolysates of Avicel and xylan, using Clostridium sp. strain no. 2. At 0.3% concentration in peptone yeast (PY) medium, pure xylose or glucose and crude hydrolysates of Avicel or xylan were converted to hydrogen at yields of 16.1 mmol or 14.6 mmol and 19.6 mmol or 18.6 mmol, per gram of substrate consumed, respectively. Alternatively, a batch culture of strain no. 2 grown in PY medium containing 1% of xylan or xylose with crude xylanase preparation and xylose alone as a reference, gave hydrogen production of 9.5 mmol or 9.6 mmol and 10.3 mmol, per gram of substrate supplemented, respectively.

Occurrence of multiple JC virus variants with distinctive regulatory sequences in the brain of a single patient with progressive multifocal leukoencephalopathy

We established 99 JC virus (JCV) DNA clones directly from the brain of a single patient with progressive multifocal leukoencephalopathy (PML). Based upon restriction patterns, the cloned viral DNAs were classified into two major groups (NY-1A and -1B) containing 53 and 35 clones, respectively, and several minor groups containing one or a few clones. The regulatory sequences of representative clones were compared with the archetypal regulatory sequence, which has been detected in JCV DNAs cloned from the urine of healthy and nonimmunosuppressed individuals. The regulatory sequence of NY-1B had the two structural features common to most PML-type regulatory regions, duplication and deletion of specific segments in the archetypal sequence, while that of NY-1A contained a small deletion and an insertion of a 29-bp sequence originating from the early region of the JCV genome. A regulatory region similar to that of NY-1A has never been detected in JCV isolates obtained thus far.

Simultaneous production of xylanase and hydrogen using xylan in batch culture of Clostridium sp. Strain X53

Abstract Clostridium sp. strain X53, newly isolated from termites, was found to produce xylanase and hydrogen in a batch culture with xylan. The maximal enzyme activity of crude xylanase produced in the culture was obtained at 50°C and pH 5.0. Xylanase activity was detectable in the culture medium (10 g/ l of xylan) after 2 h, and reached a peak (1,252 IU/ml) after 8-h cultivation at 40°C and pH 6.0. The most efficient production of hydrogen from xylan was coincidently achieved under the same conditions as xylanase production, at 40°C and pH 6.0. The maximal hydrogen evolution rate and total hydrogen yield were 240 ml/ l /h after 8-h cultivation and 1,254 ml/ l for 24 h, respectively, although the amount of hydrogen produced from xylan was equivalent to about 73% of that from the 4.7 g of xylose consumed.