Salivary Alpha-Amylase Activity and Mild Cognitive Impairment among Japanese Older Adults: The Toon Health Study

BACKGROUND

There is growing interest in examining objective markers for early identification and behavioral intervention to prevent dementia and mild cognitive impairment in clinical and community settings.

OBJECTIVE

To investigate the association between salivary alpha-amylase as an objective measure of psychological stress response and mild cognitive impairment for the implication of psychological stress in the development of mild cognitive impairment.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study involved 865 participants aged ≥ 65 years. A saliva sample was collected in the morning, and the levels of salivary alpha-amylase were assayed. Mild cognitive impairment was evaluated using the Japanese version of the Montreal Cognitive Assessment; a score < 26 was indicative of mild cognitive impairment. A multivariable logistic regression model was used to examine the association of salivary alpha-amylase and mild cognitive impairment after adjusting for age, sex, current drinking status, current smoking status, body mass index, hypertension, diabetes mellitus, physical activity, education, social support, social network, and heart rate variability.

RESULTS

Salivary alpha-amylase was associated with mild cognitive impairment (the multivariable-adjusted odds ratio [95% confidence interval] for the 1-standard deviation increment of log-transformed salivary alpha-amylase was 1.24 [1.07-1.44]). This significant association persisted after adjusting for various confounding factors.

CONCLUSION

Elevation of salivary alpha-amylase was associated with mild cognitive impairment among Japanese community-dwelling older adults. This suggests that salivary alpha-amylase is a useful objective marker of psychological stress responses associated with mild cognitive impairment.

Large Impact of the Decay of Niobium Isomers on the Reactor ν[over ¯]_{e} Summation Calculations

Even mass neutron-rich niobium isotopes are among the principal contributors to the reactor antineutrino energy spectrum. They are also among the most challenging to measure due to the refractory nature of niobium, and because they exhibit isomeric states lying very close in energy. The β-intensity distributions of ^{100gs,100m}Nb and ^{102gs,102m}Nb β decays have been determined using the total absorption γ-ray spectroscopy technique. The measurements were performed at the upgraded Ion Guide Isotope Separator On-Line facility at the University of Jyväskylä. Here, the double Penning trap system JYFLTRAP was employed to disentangle the β decay of the isomeric states. The new data obtained in this challenging measurement have a large impact in antineutrino summation calculations. For the first time the discrepancy between the summation model and the reactor antineutrino measurements in the region of the shape distortion has been reduced.

Summation Calculations for Reactor Antineutrino Spectra, Decay Heat and Delayed Neutron Fractions Involving New TAGS Data and Evaluated Databases

Three observables of interest for present and future reactors depend on the β decay properties of the fission products: antineutrinos from reactors, the reactor decay heat and delayed neutron emission. In these proceedings, we present new results from summation calculations of the first two quantities quoted above, performed with evolved independent yields coupled with fission product decay data, from various nuclear data bases or models. New TAGS results from the latest experiment of the TAGS collaboration at the JYFL facility of Jyväskylä will be displayed as well as their impact on the antineutrino spectra and the decay heat associated to fission pulses of the main actinides.

In Vitro Analysis of AcrySof Intraocular Lens Glistening

PURPOSE

The authors studied the effects of changes in packaging solution temperature on the development of glistening in acrylic intraocular lenses (AcrySof, Alcon).

METHODS

Glistening was examined by slit lamp at each condition. In Experiment 1, AcrySof lenses were soaked in physiologic saline adjusted to 15 degrees C and 37 degrees C in an incubator. In Experiment 2, AcrySof lenses were soaked in physiologic saline adjusted to 37 degrees C and 60 degrees C for 5 min, then stored in physiologic saline adjusted to 15 degrees C. In Experiment 3, glistening formation was induced in AcrySof lenses by soaking them in warm water (37 degrees C). The lenses were allowed to dry at 15 degrees C and then soaked in physiologic saline adjusted to 15 degrees C. After storage of dry AcrySof lenses at 37 degrees C in an incubator for 10 months followed by soaking in physiologic saline adjusted to 15 degrees C, glistening formation was evaluated in Experiment 4.

RESULTS

Glistening became observable after 1 month, despite the temperature having been lowered to 15 degrees C. No glistening was observed in the lenses soaked in physiologic saline adjusted to 37 degrees C after 5 min, but glistening was observed 1 month after soaking. When allowed to dry at 15 degrees C, the glistening decreased. After 1 month of soaking at 15 degrees C, glistening was again observable.

CONCLUSIONS

AcrySof lenses soaked in warm water for a short time may change characteristics, and therefore, close monitoring of the temperature and time of soaking is necessary to prevent glistening formation.

Induction of Calcification in MC3T3-E1 Cells by Inorganic Polyphosphate

Relatively large amounts of inorganic polyphosphate [poly(P)] (400 μM) have been found in normal osteoblasts. The effect of poly(P) with an average chain length of 65 phosphate residues on cell calcification was therefore investigated with the use of MC3T3-E1 cells. Expression of both osteopontin and osteocalcin was induced by poly(P) (0.1 ~ 1 mM), and cells treated with poly(P) were strongly stained by alizarin red. In addition, the level of alkaline phosphatase activity induced in poly(P)-treated cells was two-fold higher than that in either orthophosphate-treated or control cells but not higher than that in cells treated with β-glycerophosphate and ascorbic acid. In contrast, however, polyphosphatase activities were activated by poly(P) treatment to levels up to six-fold greater than that in controls. MC3T3-E1 cells may utilize poly(P) as a phosphate source for calcification rather than phosphate sources that are mainly produced by ALPase. Poly(P)-dependent induction of polyphosphatase activities may therefore promote calcification in MC3T3-E1 cells.

Total Absorption Spectroscopy Study of (92)Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. (92)Rb makes the dominant contribution to the reactor antineutrino spectrum in the 5-8 MeV range but its decay properties are in question. We have studied (92)Rb decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed.

Anemia amelioration by lactose infusion during trypanosomosis could be associated with erythrocytes membrane de-galactosylation

African trypanosomosis is a potentially fatal disease that is caused by extracellular parasitic protists known as African trypanosomes. These parasites inhabit the blood stream of their mammalian hosts and produce a number of pathological features, amongst which is anemia. Etiology of the anemia has been partly attributed to an autoimmunity-like mediated erythrophagocytosis of de-sialylated red blood cells (dsRBCs) by macrophages. Lactose infusion to infected animals has proven effective at delaying progression of the anemia. However, the mechanism of this anemia prevention is yet to be well characterized. Here, the hypothesis of a likely induced further modification of the dsRBCs was investigated. RBC membrane galactose (RBC m-GAL) and packed cell volume (PCV) were measured during the course of experimental trypanosomosis in mice infected with Trypanosoma congolense (stb 212). Intriguingly, while the membrane galactose on the RBCs of infected and lactose-treated mice (group D) decreased as a function of parasitemia, that of the lactose-untreated infected group (group C) remained relatively constant, as was recorded for the uninfected lactose-treated control (group B) animals. At the peak of infection, the respective cumulative percent decrease in PCV and membrane galactose were 30 and 185 for group D, and 84 and 13 for group C. From this observed inverse relationship between RBCs membrane galactose and PCV, it is logical to rationalize that the delay of anemia progression during trypanosomosis produced by lactose might have resulted from an induction of galactose depletion from dsRBCs, thereby preventing their recognition by the macrophages.

Histochemical characteristics of calcium binding S100 proteins and bone morphogenetic proteins in chondro-osseous tumors

Immunohistochemical distribution of the Ca2+ binding proteins S100A1, S100A2, S100A4, S100A6, S100B, and bone morphogenetic protein (BMP) in chondro-osseous tumors and lesions, both benign and malignant, was investigated using specific anti S100 protein and BMP antibodies. Chondrogenic tumor cells of chondro-osseous lesions were characterized by the presence of marked staining for S100B and BMP, while they were only faintly reactive for S100A1, S100A2, S100A4 and S100A6. Dense fibrous connective tissue in osseous tumor and ossifying fibroma showed moderate immunoreactivity for S100A1, S100A4 and BMP. Immunoreactivity of S100A2, prominent in epidermal basal cells and associated or homologous cells of epidermal tumors or skin appendages tumors, was not found in cartilage and bone forming cells. Biological roles of S100B in chondroid cells may involve Ca2+-signaling in precalcified tissue, cytoskeletal protein organization and matrix formation since glycosaminoglycan synthesis is mediated by calcium ions. S100B positive cells in chondro-osseous structures also strongly expressed BMP. The present study allowed us to conclude that among the S100 proteins, the S100B in particular and S100A1, S100A4 and S100A6 but not S100A2 may be involved in the process of tumorigenesis of chondro-osseous tumors and BMP may have an important role in the chondroid and osseous differentiation. The detailed biological role of S100 proteins in chondro-osseous tumors is under investigation.

Enhanced initial bone regeneration with inorganic polyphosphate-adsorbed hydroxyapatite

Inorganic polyphosphate (poly(P)) can promote binding between fibroblast growth factors and their receptors and enhance osteoblastic cell differentiation and calcification. This study evaluated the possibilities for poly(P) adsorbed onto interconnected porous calcium hydroxyapatite (IP-CHA) as a new bone regeneration material. Prepared 1%, 5%, 25% and 50% poly(P)/IP-CHA composites showed the elution peak of poly(P) between 15 and 20 min, respectively, with the highest value from 50% poly(P)/IP-CHA in vitro. Histologically, at 1 week of placement into the femur of rabbits, granulation tissue had penetrated into the pores in all composites and IP-CHA as a control. In contrast, at 2 weeks of placement, newly formed lamellar bone was found in all groups, although a higher amount of bone regeneration was obviously formed in the 25% and 50% poly(P)/IP-CHA with a significantly higher value of bone regeneration ratio of 50% poly(P)/IP-CHA. These results indicate that 25% and 50% poly(P)/IP-CHA composites may enhance initial bone regeneration.

Distribution of aerobic bacteria which contain bacteriochlorophyll a

Sixteen strains of aerobic bacteria which contain bacteriochlorophyll a were isolated from the samples collected in aerobic marine environments: thalli of Enteromorpha linza, Porphyra sp., Sargussum horneri; beach sand; and the surface seawater from Aburatsubo Inlet. When they occurred, their proportions among the aerobic heterotrophic populations ranged from 0.9 to 1.1% in the seaweed samples and from 1.2 to 6.3% in the beach sand samples and were 0.9% in the seawater sample. The results suggested that the aerobic photopigmented bacteria widely inhabit aerobic marine environments.

Effect of combined application of bFGF and inorganic polyphosphate on bioactivities of osteoblasts and initial bone regeneration

Basic fibroblast growth factor (bFGF) and inorganic polyphosphate (poly(P)) have been recognized as therapeutic agents that enhance bone regeneration. It has also been shown that poly(P) may enhance the mitogenic activity of bFGF. The purpose of this study is to evaluate the combined effect of bFGF and poly(P) on bioactivities of osteoblasts and initial bone regeneration in vitro and in vivo. MC3T3-E1 cells were treated with bFGF, poly(P) or bFGF+poly(P), then subjected to cell proliferation assay, alkaline phosphatase (ALP) activity measurement, quantitative real-time reverse transcription-polymerase chain reaction and Alizarin S Red staining. In an in vivo study, bFGF-, poly(P)- and bFGF+poly(P)-modified interconnected porous hydroxyapatite (IPHA) complexes were fabricated, and placed into the femurs of rabbits to evaluate new bone formation histologically and histomorphometrically. The highest enhancement of cell proliferation were observed in those treated with bFGF+poly(P) on days 5 and 7. Cells treated with bFGF+poly(P) also exhibited increased ALP activity on days 5 and 10, up-regulated mRNA levels of osteocalcin and osteopontin, and enhanced calcification when compared to the non-treated cells. In vivo, the highest bone formation ratio was observed in bFGF+poly(P)-modified IPHA complexes. This study indicated that co-application of bFGF and poly(P) may provide enhanced bone formation by modulating cell proliferation and the mineralization process. It is anticipated that a combined application of bFGF and poly(P) can provide a novel method for bone regeneration in clinical use.

Xenopus W-linked DM-W induces Foxl2 and Cyp19 expression during ovary formation

The molecular mechanisms of vertebrate ZZ/ZW-type sex-determining systems remain unclear. We recently indicated that a W-linked gene, DM-W is a likely ovary-determining gene in Xenopus laevis. We first examined whether Cyp19 for estrogen-synthesizing enzyme P450 aromatase and Foxl2 showed female-specific expression in developing gonads. Both genes showed much higher expression in ZW than in ZZ gonads during and after sex determination. Importantly, transgenic ZZ gonads expressing exogenous DM-W at the sex-determining stage showed a ZW-type pattern of Cyp19 and Foxl2 expression. These results suggest that DM-W up-regulates Cyp19 and Foxl2 expression to guide primary ovary development in X. laevis.

Inorganic polyphosphate: a possible stimulant of bone formation

Inorganic polyphosphates [Poly(P)] are often distributed in osteoblasts. We undertook the present study to verify the hypothesis that Poly(P) stimulates osteoblasts and facilitates bone formation. The osteoblast-like cell line MC 3T3-E1 was cultured with Poly(P), and gene expression and potential mineralization were evaluated by reverse-transcription polymerase chain-reaction. Alkaline phosphatase activity, von Kossa staining, and resorption pit formation analyses were also determined. The potential role of Poly(P) in bone formation was assessed in a rat alveolar bone regeneration model. Poly(P) induced osteopontin, osteocalcin, collagen 1alpha, and osteoprotegerin expression and increased alkaline phosphatase activity in MC 3T3-E1 cells. Dentin slice pit formation decreased with mouse osteoblast and bone marrow macrophage co-cultivation in the presence of Poly(P). Promotion of alveolar bone regeneration was observed locally in Poly(P)-treated rats. These findings suggest that Poly(P) plays a role in osteoblastic differentiation, activation, and bone mineralization. Thus, local poly(P) delivery may have a therapeutic benefit in periodontal disease.

Genome size, karyotype, meiosis and a novel extra chromosome in Torenia fournieri, T. baillonii and their hybrid

Torenia is a suitable model plant to study plant fertilization because of its protruding embryo sac. However, information on the genomes and chromosomes of this species is limited. We determined the genome sizes of T. fournieri Linden and T. baillonii Godefr as 1.71 pg x 10(8) bp and 1.67 x 10(8) bp, respectively. The small genome size of these species suggests their superiority as the targets for molecular cloning studies. Furthermore, karyotypes of T. fournieri and T. baillonii were determined using FISH probed with 5S rDNA, 45S rDNA and species-specific centromere repetitive sequences. Although the two species have similar genome size, number of chromosomes, centromere repeats and 5S rDNA loci were varied. Observation of meiosis in the F(1) hybrid revealed that all chromosomes except one of T. fournieri paired well with the chromosomes of T. baillonii throughout the entire length of the chromosomes including species-specific centromeric regions. One exceptional chromosome of T. fournieri behaved as a univalent and was not always required for gametogenesis. The present results provide the basis for the molecular genetics in Torenia.

A novel ATP regeneration system using polyphosphate-AMP phosphotransferase and polyphosphate kinase

Polyphosphate-AMP phosphotransferase (PAP) and polyphosphate kinase (PPK) were used for designing a novel ATP regeneration system, named the PAP-PPK ATP regeneration system. PAP is an enzyme that catalyzes the phospho-conversion of AMP to ADP, and PPK catalyzes ATP formation from ADP. Both enzymes use inorganic polyphosphate [poly(P)] as a phosphate donor. In the PAP-PPK ATP regeneration system, ATP was continuously synthesized from AMP by the coupling reaction of PAP and PPK using poly(P). Poly(P) is a cheap material compared to acetyl phosphate, phosphoenol pyruvate and creatine phosphate, which are phosphate donors used for conventional ATP regeneration systems. To achieve efficient synthesis of ATP from AMP, an excessive amount of poly(P) should be added to the reaction solution because both PAP and PPK consume poly(P) as a phosphate donor. Using this ATP generation reaction, we constructed the PAP-PPK ATP regeneration system with acetyl-CoA synthase and succeeded in synthesizing acetyl-CoA from CoA, acetate and AMP. Since too much poly(P) may chelate MG2+ and inhibit enzyme activity, the Mg2+ concentration was optimized to 24 mM in the presence of 30 mM poly(P) in the reaction. In this reaction, ATP was regenerated 39.8 times from AMP, and 99.5% of CoA was converted to acetyl-CoA. In addition, since the PAP-PPK ATP regeneration system can regenerate GTP from GMP, it could also be used as a GTP regeneration system.

Overeruption without root exposure of third molars and periodontal health in the mandible

Bone formation is seen around the third molar even when the tooth is exposed to the oral environment due to overeruption. To determine if overeruption of the third molar with or without root exposure is related to the status of the exposure of other teeth in the mandible, using orthopantomographs, 424 third molars were studied in 371 patients who were over 41 years of age. The rate of overeruption and root exposure in third molars was measured, and its relationship to the number of teeth lost and the rate of root exposure in other teeth in the mandible was analyzed. Tooth loss in the group of third molars with overeruption without root exposure was greater than in that without overeruption or root exposure in men, whereas the relationship was not seen in women. We found that root exposures of other teeth in the group of third molars with overeruption without root exposure were significantly smaller than in those with root exposure in both genders. Third molars with overeruption without root exposure, in which bone formation was easy to observe for radiographic diagnosis, were correlated with periodontal health in the mandible, suggesting a component of precision determination for predicting resistance to periodontitis.

Generalized synchronization of chaos in He-Ne lasers

We experimentally demonstrate synchronization of chaos in one-way coupled He-Ne lasers with optical feedback. We observe different types of synchronization such as identical synchronization, inverse synchronization, and random amplification. These dynamics are maintained only for a short duration of several hundred milliseconds. We also observe generalized synchronization of chaos by using one master and two slave lasers. The generalized synchronization is achieved for a long duration of tens of seconds under injection locking. The generalized synchronization is always maintained while the injection locking is achieved.

Measurement of hypocretin/orexin content in the mouse brain using an enzyme immunoassay: the effect of circadian time, age and genetic background

The hypocretins (1 and 2) have emerged as key regulators of sleep and wakefulness. We developed a high-throughput enzyme immunoassay (EIA) to measure total brain hypocretin levels from large numbers of mice. Hypocretin levels were not altered by circadian time or age. However, significant differences in one or both hypocretin peptides were observed between different mouse strains. We studied hypocretin levels in knockout and transgenic mouse models with obesity, circadian gene mutations or monoaminergic defects. Compared to controls, only histamine receptor knockouts had lower hypocretin levels. This was most pronounced in H1 receptor knockouts suggesting the existence of a positive feedback loop between hypocretin and histaminergic neurons.

Laparoscopic hepatectomy for extrahepatic growing tumor. Surgical strategy based on extrahepatic growing index

BACKGROUND

This article describes the operative procedures, varying difficulties, and required instrumentation for performing laparoscopic hepatectomy (LH) on the basis of a lesion's extrahepatic growing (EG) index, as calculated by computed tomography (CT).

METHODS

Laparoscopic partial hepatectomy cases were divided into the following two groups: an EG tumor group (n = 11) and an intrahepatic tumor group (n = 8). The surgical procedures, operative results, and laparoscopic instrumentation for these two groups were compared based on the EG index (/cm2; maximum diameter of tumor pedicle/maximum vertical diameter of tumor/area of the tumor).

RESULTS

The mean operative time was significantly shorter and the mean blood loss was significantly less in the EG tumor group than in the intrahepatic tumor group. In addition, in the EG tumor group, there were significant differences in mean operative time and mean blood loss related to the values associated with the EG index (p <0.05, P <0.01). The selection of laparoscopic instruments was based on the EG index, as follows: (a) lesions with an EG index >5/cm2 underwent resection in combination with a microwave tissue coagulator and an ultrasonic surgical aspirator (13 cases, including intrahepatic tumor cases); (b) lesions with an EG index of 5-15/cm2 underwent resection in combination with a microwave tissue coagulator and laparosonic coagulating shears (four cases); (c) lesions with an EG index <%15/cm2 underwent resection with a laparoscopic linear stapler (two cases).

CONCLUSION

Our preliminary experience leads us to believe that it is useful to calculate the EG index by CT scan before formulating the technical strategy for a subsequent LH procedure.

Three TNFalpha single nucleotide polymorphisms in the Japanese population

BACKGROUND

Tumour necrosis factor-alpha (TNFalpha) is an essential regulator of immune responses and is implicated to relate to several types of disease susceptibilities. Population information on polymorphisms is essential for the study of genetic diseases.

AIM

To obtain accurate information about single nucleotide polymorphisms (SNPs) in the TNFalpha gene in the Japanese population.

SUBJECTS AND METHODS

The entire TNFalpha gene was screened for SNPs by directly sequencing 48 chromosomes derived from 24 unrelated Japanese individuals. Allele frequencies of each polymorphism were determined and compared with those previously reported in other populations.

RESULTS

Three SNPs, -308G/A at nt -308, IVS1 + 125G/A at nt 492 and IVS3 + 104G/A at nt 1359 were observed, of which one (IVS3 + 104G/A at nt 1359) was novel. In addition, allele frequencies of -308G/A were remarkably different from those presented in the NCBI dbSNP, indicating a significant ethnic difference.

CONCLUSIONS

The polymorphisms and allele frequencies obtained in this study will be useful for genetic studies of common diseases such as osteoporosis and rheumatoid arthritis in the Japanese population.

Hypocretin stimulates [(35)S]GTP gamma S binding in Hcrtr 2-transfected cell lines and in brain homogenate

In vitro functional analyses of hypocretin/orexin receptor systems were performed using [(125)I]hypocretin radioreceptor and hypocretin-stimulated [(35)S]GTP gamma S binding assay in cell lines expressing human or canine (wild-type and narcoleptic-mutation) hypocretin receptor 2 (Hcrtr 2). Hypocretin-2 stimulated [(35)S]GTP gamma S binding in human and canine Hcrtr 2 expressing cell lines, while cell lines expressing the mutated canine Hcrtr 2 did not exhibit specific binding for [(125)I]hypocretin or hypocretin-stimulated [(35)S]GTP gamma S. In rat brain homogenates, regional specific hypocretin-stimulated [(35)S]GTP gamma S binding was also observed. Hypocretin-stimulated [(35)S]GTP gamma S binding, may thus be a useful functional assay for hypocretin receptors in both cell lines and brain tissue homogenates.

Thirteen single-nucleotide polymorphisms in the human osteopontin gene identified by sequencing of the entire gene in Japanese individuals

Osteopontin (OPN) is one of the major noncollagenous bone matrix proteins produced by osteoblasts and osteoclasts. We systematically surveyed the entire structure of the OPN gene for single-nucleotide polymorphisms (SNPs) by directly sequencing 48 alleles derived from 24 unrelated Japanese individuals. We identified 13 SNPs in the OPN gene. Ten polymorphisms were identified in introns 1, 3, and 5; 2 in the coding region of exons 6 and 7; and 1 in the 3' untranslated region of exon 7. Allele frequencies for some of the polymorphisms were significantly different from those reported in the United States National Center for Biotechnology Information (NCBI) dbSNP database. These polymorphisms will be useful in genetic studies to evaluate the role of OPN proteins in bone metabolism.

Linkage disequilibrium and haplotype analysis among ten single-nucleotide polymorphisms of interleukin 11 identified by sequencing of the gene

Interleukin (IL11) is a member of the interleukin 6 (IL6)-related cytokine subfamily, which stimulates T cell-dependent development of immunoglobulin-producing B cells. IL11 is also an important paracrine regulator of bone metabolism that induces formation of osteoclasts. In the work reported here, we sequenced the entire IL11 structural gene of 48 alleles in a Japanese test population. These experiments identified ten single-nucleotide polymorphisms (SNPs) and determined their allelic frequencies. One polymorphism was identified upstream of exon 1, one in exon 3, four in intron 4 and four in the 3' untranslated region (3'UTR) of exon 5. Based on the genotype data, we constructed six haplotypes in the tested population. Two-way comparisons of SNPs revealed two combinations in complete linkage disequilibrium, one with SNPs at nucleotide positions 2753, 3644, 5154, and 5568, and another with SNPs at positions 3686, 5141, and 5734. These results will be useful in disease-association studies where a contribution of the human IL11 gene has been suspected, especially in disorders affecting immune response and bone metabolism.

Cloning and sequencing of the beta-glucosidase gene from Acetobacter xylinum ATCC 23769

The beta-glucosidase gene (bglxA) was cloned from the genomic DNA of Acetobacter xylinum ATCC 23769 and its nucleotide sequence (2200 bp) was determined. This bglxA gene was present downstream of the cellulose synthase operon and coded for a polypeptide of molecular mass 79 kDa. The overexpression of the beta-glucosidase in A. xylinum caused a tenfold increase in activity compared to the wild-type strain. In addition, the action pattern of the enzyme was identified as G3ase activity. The deduced amino acid sequence of the bglxA gene showed 72.3%, 49.6%, and 45.1% identity with the beta-glucosidases from A. xylinum subsp. sucrofermentans, Cellvibrio gilvus, and Mycobacterium tuberculosis, respectively. Based on amino acid sequence similarities, the beta-glucosidase (BglxA) was assigned to family 3 of the glycosyl hydrolases.