Cognitive and affective functions in Alzheimer's disease patients with metabolic syndrome

BACKGROUND AND PURPOSE

The influence of metabolic syndrome (MetS) on cognitive and affective functions in patients with Alzheimer's disease (AD) was examined.

METHODS

A total of 570 AD patients were divided into two subgroups depending on waist circumference (WC) (normal versus achieving Japanese diagnostic criteria of MetS). Afterwards, the AD control subgroup was defined as those normal WC patients with no vascular risk factors (VRFs). The AD with MetS (AD-MetS) subgroup was defined as the MetS WC group who had two or more VRFs to qualify as having MetS. Cognitive and affective functions, insulin resistance, vascular endothelial function and white matter changes between AD-MetS and AD controls were compared.

RESULTS

Scores on the Mini-Mental State Examination, Hasegawa Dementia Score-Revised, Frontal Assessment Battery and Montreal Cognitive Assessment were worse in the AD-MetS group than in AD controls, but the difference was not significant. Some analyses were conducted twice, once including all patients and once including only late-elderly patients. Scores on the Geriatric Depression Scale were found to be significantly higher for AD-MetS than for AD controls (all ages, late-elderly), as were those for apathy (late-elderly). Furthermore, both the homeostasis model assessment of insulin resistance and reactive hyperemia index scores were significantly worse in AD-MetS than in AD controls, whilst white matter changes showed a tendency to be worse.

CONCLUSIONS

Greater cognitive and affective decline occurs in patients with AD-MetS than in those without. Further, insulin resistance and vascular endothelial dysfunction are strongly correlated with AD-MetS before pathological white matter changes can be observed.

Involvement of flocculin in negative potential-applied ITO electrode adhesion of yeast cells

The purpose of this study was to develop novel methods for attachment and cultivation of specifically positioned single yeast cells on a microelectrode surface with the application of a weak electrical potential. Saccharomyces cerevisiae diploid strains attached to an indium tin oxide/glass (ITO) electrode to which a negative potential between −0.2 and −0.4 V vs. Ag/AgCl was applied, while they did not adhere to a gallium-doped zinc oxide/glass electrode surface. The yeast cells attached to the negative potential-applied ITO electrodes showed normal cell proliferation. We found that the flocculin FLO10 gene-disrupted diploid BY4743 mutant strain (flo10Δ /flo10Δ) almost completely lost the ability to adhere to the negative potential-applied ITO electrode. Our results indicate that the mechanisms of diploid BY4743 S. cerevisiae adhesion involve interaction between the negative potential-applied ITO electrode and the Flo10 protein on the cell wall surface. A combination of micropatterning techniques of living single yeast cell on the ITO electrode and omics technologies holds potential of novel, highly parallelized, microchip-based single-cell analysis that will contribute to new screening concepts and applications.

Yeast Saccharomyces cerevisiae were selectively attached on the negative potential-applied indium tin oxide/glass electrode. Mechanisms of the yeast cell attachment involve Flocculin Flo10 proteins.

Lichen Planus Annularis: An Immunohistochemical Study

Lichen planus annularis is a relatively rare skin manifestation of lichen planus. The mechanisms in the formation of annular lesions are not fully understood. We reported here a 57-year-old female with this disease. The eruption initially occurred as lichen-papules, then enlarged (bean-sized, umbilicated small plaques), and finally developed annular manifestations. We performed immunohistochemical examinations of specimens taken from different types of eruptions. In all specimens, HLA-DR was expressed in the focal keratinocytes adjacent to the dermal HLA-DR positive cell infiltration. Both in the initial papule and in the final annular lesion, expression of ICAM-1 was present only in the keratinocytes above the dermal cell infiltration, similar to HLA-DR. It is of interest that, in the umbilicated small plaques, the peripheral epidermis other than the central site extensively reacted to ICAM-1. LFA-1 expression was most prominent in the mononuclear cells impinging on the dermo-epidermal junction in all specimens. In addition, in the periphery of the umbilicated small plaques, which showed no bandlike dense cell infiltration nor degeneration of basement membrane, TNF-alpha, but not LFA-1, was positive in the infiltrated cells of the upper dermis. These results suggest that expressions of ICAM-1 and TNF-alpha in the peripheral keratinocytes and dermal infiltrated cells are important molecular events in the mechanisms of formation of the annular lesions.

Crystal structure of the catalytic domain of a GH16 β-agarase from a deep-sea bacterium, Microbulbifer thermotolerans JAMB-A94

A deep-sea bacterium, Microbulbifer thermotolerans JAMB-A94, has a β-agarase (MtAgaA) belonging to the glycoside hydrolase family (GH) 16. The optimal temperature of this bacterium for growth is 43–49 °C, and MtAgaA is stable at 60 °C, which is one of the most thermostable enzymes among GH16 β-agarases. Here, we determined the catalytic domain structure of MtAgaA. MtAgaA consists of a β-jelly roll fold, as observed in other GH16 enzymes. The structure of MtAgaA was most similar to two β-agarases from Zobellia galactanivorans, ZgAgaA, and ZgAgaB. Although the catalytic cleft structure of MtAgaA was similar to ZgAgaA and ZgAgaB, residues at subsite −4 of MtAgaA were not conserved between them. Also, an α-helix, designated as α4′, was uniquely located near the catalytic cleft of MtAgaA. A comparison of the structures of the three enzymes suggested that multiple factors, including increased numbers of arginine and proline residues, could contribute to the thermostability of MtAgaA.

Characterization of primary structure and tissue expression profile of the chicken apical sodium-dependent bile acid transporter mRNA

The ileal apical sodium-dependent bile acid cotransporter (ASBT) plays an essential role in the absorption of bile acids from intestinal lumina. ASBT cDNA has been cloned from mammalian and fish species, and the primary structure of the protein and expression properties of the mRNA have been characterized. In this study, we identified chicken ASBT mRNA by cDNA cloning. Chicken ASBT cDNA consisted of 91 bp of the 5'-untranslated region, 1,083 bp of the coding region, and 1,896 bp of the 3'-untranslated region. The cDNA encoded a protein of 360 amino acids showing significant sequence identity with mammalian and fish ASBT. The amino acid residues known to participate in the functions of mammalian ASBT were conserved in chicken ASBT. Real-time polymerase chain reaction analysis revealed that chicken ASBT mRNA was expressed at markedly higher levels in the ileum and proximal colon/rectum, relatively lower levels in the kidney, and very low levels in the jejunum and cecum. Expression levels in the ileum markedly increased after hatching, reached the highest levels on day 7 posthatching, and then decreased to adult levels. A similar expression pattern was observed in the proximal colon/rectum except for the significant decrease from day 7 posthatching to day 21 posthatching. These results suggest that chicken ASBT functions as a bile acid transporter in the ileum and proximal colon/rectum, particularly during the early posthatching period.

Continuous Chitosan Hydrolyzate Production by Immobilized Chitosanolytic Enzyme fromEnterobactersp. G-1

Chitosanolytic enzymes from Enterobacter sp. G-1 were immobilized on various carriers to continuously hydrolyze chitosan. Four different carriers were tested: FE-3901 (strong basic anion exchange resin, ionic binding), glutaraldehyde-treated FE-4612 (weak basic anion exchange resin, cross-linking), Chitopearl (chitosan beads), and alginate calcium. Glutaraldehyde-treated FE-4612 and Chitopearl immobilized more protein than the others. The enzyme immobilized on FE-3901 had the greatest activity. The activity of enzyme immobilized on FE-3901 decreased rapidly when exposed to a continuous flow of 1% chitosan. The enzyme immobilized with Chitopearl retained more than 50% of its original activity after 17 days, and the activity was fully restored by re-immobilization.

Enzymatic Properties and Nucleotide and Amino Acid Sequences of a Thermostable β-Agarase from the Novel Marine Isolate, JAMB-A94

A gene, agaA, for a novel beta-agarase from the marine bacterium JAMB-A94 was cloned and sequenced. The 16S rDNA of the isolate had the closest match, of only 94.8% homology, with that from Microbulbifer salipaludis JCM11542(T). The agaA gene encoded a protein with a calculated molecular mass of 48,203 Da. The deduced amino acid sequence showed 37-66% identity to those of known agarases in glycoside hydrolase family 16. A carbohydrate-binding module-like amino acid sequence was found in the C-terminal region. The recombinant enzyme was hyper-produced extracellularly when Bacillus subtilis was used as a host. The purified enzyme was an endo-type beta-agarase, yielding neoagarotetraose as the main final product. It was very thermostable up to 60 degrees C. The optimal pH and temperature for activity were around 7.0 and 55 degrees C respectively. The activity was not inhibited by EDTA (up to 100 mM) and sodium dodecyl sulfate (up to 30 mM).

Order, criticality, and excitations in the extended Falicov-Kimball model

Using exact numerical techniques, we investigate the nature of excitonic (electron-hole) bound states and the development of exciton coherence in the one-dimensional half-filled extended Falicov-Kimball model. The ground-state phase diagram of the model exhibits, besides band-insulator and staggered orbital ordered phases, an excitonic insulator (EI) with power-law correlations. The criticality of the EI state shows up in the von Neumann entropy. The anomalous spectral function and condensation amplitude provide the binding energy and coherence length of the electron-hole pairs which, on their part, point towards a Coulomb interaction driven crossover from BCS-like electron-hole pairing fluctuations to tightly bound excitons. We show that while a mass imbalance between electrons and holes does not affect the location of the BCS-BEC crossover regime, it favors staggered orbital ordering to the disadvantage of the EI. Within the Bose-Einstein condensation (BEC) regime, the quasiparticle dispersion develops a flat valence-band top, in accord with the experimental finding for Ta2NiSe5.

Thalassospira alkalitolerans sp. nov. and Thalassospira mesophila sp. nov., isolated from a decaying bamboo sunken in the marine environment, and emended description of the genus Thalassospira

Two marine bacteria, designated strains MBE#61T and MBE#74T, were isolated from a piece of sunken bamboo in the marine environment in Japan. Both of these strains were Gram-stain-negative, but had different cell shapes: MBE#61T was spiral, whereas MBE#74T was rod-shaped. The temperature, pH and salt concentration ranges for growth of strain MBE#61T were 4–38 °C (optimal at 32 °C), pH 4.5–11.0 (optimal at pH 7.0–8.0) and 1–11 % (optimal at 2 %) NaCl, whereas those of strain MBE#74T were 4–36 °C (optimal at 30 °C), pH 4.0–10.5 (optimal at pH 7.0–8.0) and 1–12 % (optimal at 4 %) NaCl. Phylogenetic analysis based on partial 16S rRNA gene sequences revealed that both strains belong to the genus Thalassospira within the class Alphaproteobacteria . Similarity between the 16S rRNA gene sequence of strain MBE#61T and those of the type strains of species of the genus Thalassospira was 97.5–99.0 %, and that of strain MBE#74T was 96.9–98.6 %; these two isolates were most closely related to Thalassospira lucentensis QMT2T. However, the DNA–DNA hybridization values between T. lucentensis QMT2T and strain MBE#61T or MBE#74T were only 16.0 % and 7.1 %, respectively. The DNA G+C content of strain MBE#61T was 54.4 mol%, and that of strain MBE#74T was 55.9 mol%. The predominant isoprenoid quinone of the two strains was Q-10 (MBE#61T, 97.3 %; MBE#74T, 93.5 %). The major cellular fatty acids of strain MBE#61T were C18 : 1ω7c (31.1 %), summed feature 3 comprising C16 : 0ω7c/iso-C15 : 0 2-OH (26.1 %) and C16 : 0 (20.9 %); those of strain MBE#74T were C16 : 0 (26.2 %), C17 : 0 cyclo (19.9 %) and C18 : 1ω7c (12.1 %). On the basis of these results, strain MBE#61T and strain MBE#74T are considered to represent novel species of the genus Thalassospira , for which names Thalassospira alkalitolerans sp. nov. and Thalassospira mesophila sp. nov. are proposed. The type strains are MBE#61T ( = JCM 18968T = CECT 8273T) and MBE#74T ( = JCM 18969T = CECT 8274T), respectively. An emended description of the genus Thalassospira is also proposed.

Draft Genome Sequence of Sphingobium sp. Strain KK22, a High-Molecular-Weight Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Isolated from Cattle Pasture Soil

Sphingobium sp. strain KK22 was isolated from a bacterial consortium that originated from cattle pasture soil from Texas. Strain KK22 grows on phenanthrene and has been shown to biotransform the high-molecular-weight (HMW) polycyclic aromatic hydrocarbon (PAH) benz[a]anthracene. The genome of strain KK22 was sequenced to investigate the genes involved in aromatic pollutant biotransformation.

Impact of antihypertensive medication adherence on blood pressure control in hypertension: the COMFORT study

BACKGROUND

It has not been fully elucidated whether antihypertensive medication adherence affects blood pressure (BP) control in hypertension cases.

AIM

To investigate the association of adherence to antihypertensive drug regimens and BP control using data from the Combination Pill of Losartan Potassium and Hydrochlorothiazide for Improvement of Medication Compliance Trial (COMFORT) study.

DESIGN

An observational analysis from a randomized controlled trial.

METHODS

A total of 203 hypertensive subjects were randomly assigned to a daily regimen of a combination pill (losartan 50 mg/hydrochlorothiazide 12.5 mg) or two pills, an angiotensin II receptor blocker and a thiazide diuretic. Medication adherence calculated based on pill counts and BPs was evaluated at 1, 3 and 6 months after randomization.

RESULTS

The subjects were divided into three groups according to their adherence, i.e. relatively low-adherence (<90%; n = 19), moderate-adherence (90-99%; n = 71) and high-adherence (100%; n = 113) groups. Clinical characteristics of the subjects including BP, sex, randomized treatments and past medical history did not differ significantly among the three groups. Achieved follow-up BPs over the 6-month treatment period, which were adjusted for age, sex, baseline BP and randomized treatment, were significantly higher in the low-adherence group (135/78 mmHg) compared with the high-adherence (130/74 mmHg; P = 0.02/0.02) and the moderate-adherence (128/74 mmHg; P = 0.003/0.02) groups.

CONCLUSION

Low adherence to an antihypertensive-drug regimen was associated with poor BP control.

Thermophilic and halophilic β-agarase from a halophilic archaeon Halococcus sp. 197A

An agar-degrading archaeon Halococcus sp. 197A was isolated from a solar salt sample. The agarase was purified by hydrophobic column chromatography using a column of TOYOPEARL Phenyl-650 M. The molecular mass of the purified enzyme, designated as Aga-HC, was ~55 kDa on both SDS-PAGE and gel-filtration chromatography. Aga-HC released degradation products in the order of neoagarohexose, neoagarotetraose and small quantity of neoagarobiose, indicating that Aga-HC was a β-type agarase. Aga-HC showed a salt requirement for both stability and activity, being active from 0.3 M NaCl, with maximal activity at 3.5 M NaCl. KCl supported similar activities as NaCl up to 3.5 M, and LiCl up to 2.5 M. These monovalent salts could not be substituted by 3.5 M divalent cations, CaCl2 or MgCl2. The optimal pH was 6.0. Aga-HC was thermophilic, with optimum temperature of 70 °C. Aga-HC retained approximately 90 % of the initial activity after incubation for 1 hour at 65-80 °C, and retained 50 % activity after 1 hour at 95 °C. In the presence of additional 10 mM CaCl2, approximately 17 % remaining activity was detected after 30 min at 100 °C. This is the first report on agarase purified from Archaea.

Microbacterium saccharophilum sp. nov., isolated from a sucrose-refining factory

A Gram-stain-positive, non-motile, non-spore-forming, rod-shaped bacterium, designated strain K-1T, was isolated from soil at a sucrose refinery in Japan. The strain grew at 9–37 °C (optimum, 30 °C) and at pH 6–11 (optimum, pH 7.0). Phylogenetic analysis based on the full-length 16S rRNA gene sequence of strain K-1T revealed that it was a member of the genus Microbacterium . High 16S rRNA gene sequence similarities were found between strains K-1T and both Microbacterium pumilum NBRC 101279T (99.7 %) and Microbacterium deminutum NRRL B-24453T (99.5 %). However, the DNA–DNA hybridization values between strain K-1T and M. pumilum NBRC 101279T and M. deminutum NRRL B-24453T were only 12 % and 10 %, respectively. The DNA G+C content of strain K-1T was 73 mol%. The major fatty acids of strain K-1T were anteiso-C15 : 0 and anteiso-C17 : 0, and the major menaquinones were MK-12 and MK-13. The diamino acid in the cell-wall peptidoglycan was lysine. On the basis of these results, strain K-1T is considered to represent a novel species of the genus Microbacterium , for which the name Microbacterium saccharophilum sp. nov. is proposed. The type strain is K-1T ( = NBRC 108778T = NCIMB 14782T).

Attachment and detachment of living microorganisms using a potential-controlled electrode

We developed an electrical modulation method for attachment and detachment of microorganisms. Living microorganisms suspended in non-nutritive media such as PBS⁻ and artificial seawater were attracted by and selectively attached to indium tin oxide (ITO)/glass electrode regions to which a negative potential was applied. The microorganisms suspended in LB medium and glucose solution were not attracted to the ITO electrode. Dead microorganisms were not attracted to the ITO electrode. The living microorganisms were retrieved after detachment from the ITO electrode by application of a high-frequency triangular wave potential. When we applied this method to separate microorganisms from deep-sea sediment, bacteria belonging to 19 phyla and 23 classes were collected without undesirable high molecular weight contaminants such as humic acids. At the phylum and class level, respectively, 95 and 87 % of the phylotypes among electrically retrieved bacteria were common to the gene clones from the direct sediment DNA extraction. This technique is a novel useful method to prepare bacterial cells in a single population or a community for metagenomic analyses.

A Fundamental Experimental Study of the Mechanisms of Warpage and Shrinkage of Polyethylene in Rotational Molding

An off-line experimental simulation of cooling and warpage of rotationally molded parts is described. Slabs of polyethylene rotationally molded parts containing thermocouples and monitored by displacement transducers are placed on a metal surface representing a mold wall. This is cooled by varying methods such as simulated water showers, fan blown air, and natural convection cooling. Temperature profiles in the mold wall and through the polymer are determined as a function of time. The position of crystallization and the development of warpage are observed. Warpage is attributed to thermal quench stresses and release of the polymer from the mold surface.

Experimental Investigation of Rotational Molding and the Characterization of Rotationally Molded Polyethylene-Parts

An experimental study of the rotational molding of polyethylene parts is presented. Specific attention is given to heating and cooling of the molding cycle and to the micro structuring and bulk characteristics. Experimental measurements of the heatup of the oven at the startup of the process is presented. The heatup of different molds in the oven is then measured and interpreted in terms of heat conduction theory and the Fourier number αt/L2. In the experiments, thick aluminium molds heated up more slowly than thinner steel molds. The cooling characteristics of mold subject to different quenching conditions were compared with water showers inducing the most rapid cooling followed by fan blowing and the slowest being in quiescent air. The order of cooling of the different molds studied followed the same order as their rates of heating as would be expected from the theory of heat conduction. Polyethylene parts formed in the molds were found to be crystalline, without orientation and to possess large spherulites. The size of the spherulites and the level of the crystallinity was highest where the cooling rate was the lowest. Uniformity of part thickness and warpage were measured. Warp age correlated with rapidity of cooling rate. This suggested a mechanism of thermal quench stresses.

Effect of bezafibrate on office, home and ambulatory blood pressure in hypertensive patients with dyslipidemia

It has been suggested that fibrates, lipid-lowering agents with a peroxisome proliferator-activated receptor-α agonistic property, lower blood pressure (BP) in some experimental models of hypertension. However, the effect of fibrates on BP in humans has been inconsistent, and there are few studies using home or ambulatory BP monitoring. We investigated the effects of bezafibrate on office, home and ambulatory BP in hypertensive patients with dyslipidemia. Thirty-two essential hypertensive patients with dyslipidemia (6 men and 26 women, mean age 65±8 years old) were assigned to a control period and a bezafibrate period (200 mg twice daily) for 8 weeks each in a randomized crossover manner. Bezafibrate significantly reduced serum triglyceride, total and low-density lipoprotein-cholesterol, blood glucose, plasma insulin, the homeostasis model assessment ratio and increased high-density lipoprotein-cholesterol. Compared with the control period, changes in office, home and 24-h BP with bezafibrate were -0.7±2.1/-1.6±1.2 mm Hg, +0.9±1.0/-0.5±0.6 and +0.8±1.4/-0.6±0.9 mm Hg, respectively. None of these differences in BP was significant. In conclusion, bezafibrate improved lipid metabolism and insulin sensitivity but did not affect office, home or ambulatory BP in hypertensive patients with dyslipidemia. Fibrates do not appear to lower BP in patients with essential hypertension.

Salinisphaera japonica sp. nov., a moderately halophilic bacterium isolated from the surface of a deep-sea fish, Malacocottus gibber, and emended description of the genus Salinisphaera

A moderately halophilic, slightly acidophilic, aerobic bacterium, designated strain YTM-1(T), was isolated from the body surface of Malacocottus gibber. Cells were Gram-stain-negative, short rods or cocci, approximately 0.9-1.1 µm long and 1.0-1.8 µm wide. Strain YTM-1(T) was able to grow with 1-30% NaCl (optimum, 7.5-10%, w/v), at 4-30 °C (optimum, 20-25 °C) and at pH 3.8-9.5 (optimum, pH 5.0-5.5). Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain YTM-1(T) belonged to the genus Salinisphaera with low similarity values to the type strains of recognized species of this genus (<94.8-94.4%). The polar lipids of strain YTM-1(T) consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, three unknown phospholipids and one unknown lipid. The predominant isoprenoid quinone was Q-8. The major fatty acids were C19:0ω8c cyclo, C18:1ω7c, C16:1ω5c and C16:0. The DNA G+C content of strain YTM-1(T) was 67.3 mol%. These phylogenetic, physiological and chemotaxonomic data indicated that strain YTM-1(T) represents a novel species of the genus Salinisphaera, for which the name Salinisphaera japonica sp. nov. is proposed. The type strain is YTM-1(T) (=JCM 18087(T)=CECT 8012(T)). An emended description of the genus Salinisphaera is also proposed.

Double exchange ferromagnetism in the Peierls insulator state

We study the effects of opening the band gap on the double exchange ferromagnetism. Applying the density-matrix renormalization group method and an analytical expansion from the dimer limit to the one-dimensional double exchange model, we demonstrate for a relevant region of the exchange coupling that, in the weak dimerization regime, the Peierls gap opens in the fully spin-polarized conduction band without affecting its ferromagnetism, whereas in the strong dimerization regime, the ferromagnetism is destroyed, and the Mott gap opens instead, leading the system to the antiferromagnetic quasi-long-range order. An insulator version of double exchange ferromagnetism is thus established.

Unique substrate specificity of a thermostable glycosyl hydrolase from an uncultured Anaerolinea, derived from bacterial mat on a subsurface geothermal water stream

To investigate novel extremozymes encoded by sequenced metagenes from a microbial community in an extreme environment, we have characterized a recombinant glycosyl hydrolase (rGH) from an uncultured bacterium within the order Chloroflexi. rGH formed insoluble bodies in an Escherichia coli protein expression system. The protein was partially dissolved by a surfactant and was enzymatically characterized. The MW of the monomeric peptide was ~62 kDa, and it formed a homodimers in buffer. It was optimally active at 65 °C and from pH 4 to 8. rGH showed hydrolytic activity for α-1,1, α-1,2 and α-1,6 linkages, including isomaltose, but not α-1,4 and β-linkages.

Peierls mechanism of the metal-insulator transition in ferromagnetic hollandite K2Cr8O16

Synchrotron x-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K(2)Cr(8)O(16) is accompanied by a structural distortion from the tetragonal I4/m to monoclinic P112(1)/a phase with a √2×√2×1 supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems.

Hyper-production and characterization of the ι-carrageenase useful for ι-carrageenan oligosaccharide production from a deep-sea bacterium, Microbulbifer thermotolerans JAMB-A94T, and insight into the unusual catalytic mechanism

A gene of unknown function from the genome of the agar-degrading deep-sea bacterium Microbulbifer thermotolerans JAMB-A94(T) was functionally identified as a ι-carrageenase gene. This gene, designated as cgiA, is located together with two β-agarase genes, agaA and agaO in a cluster. The cgiA gene product is 569 amino acids and shares 29% identity over 185 amino acids with the ι-carrageenase from Zobellia galactanivorans Dsij DSM 12802. Recombinant, cgiA-encoded ι-carrageenase (55 kDa) was hyper-produced in Bacillus subtilis. The recombinant enzyme shows maximal activity at 50°C, the highest reported optimal temperature for a carrageenase. It cleaved β-1,4 linkages in ι-carrageenan to produce a high ratio of ι-carrageenan tetramer, more than 75% of the total product, and did not cleave the β-1,4 linkages in κ- or λ-carrageenan. Therefore, this enzyme may be useful for industrial production of ι-carrageenan oligosaccharides, which have demonstrated antiviral potential against diverse viruses. Furthermore, we performed site-directed mutagenesis on the gene to identify the catalytic amino acid residues. We demonstrated that a conserved Glu351 was essential for catalysis; however, this enzyme lacked a catalytic Asp residue, which is generally critical for the catalytic activity of most glycoside hydrolases.

Visible Electroluminescence from Pn Junction Type μc-Sic/ Porous Si / c-Si Structures

We have fabricated two kinds of n-type microcrystalline silicon carbon (μc-SiC) / porous silicon (PS) / p-type crystalline silicon (c-Si) pn junctions and demonstrated a visible light emission from them. We have observed three types of visible light emission; an uniform red light emission at a forward current above 12mA/cm2 for the pn junction using a 0.2–0.4 Qcm c-Si substrate, and a very weak white light emission at a forward current of about 90 mA/mm2 and a strong orange-red light emission at a forward current from 200 to 619 mA/mm2for the pn junction using a 3.5–4.5 Ωcm c-Si substrate.

Natronoarchaeum mannanilyticum gen. nov., sp. nov., an aerobic, extremely halophilic archaeon isolated from commercial salt

Strain YSM-123T was isolated from commercial salt made from Japanese seawater in Niigata prefecture. Optimal NaCl and Mg2+ concentrations for growth were 4.0–4.5 M and 5 mM, respectively. The isolate was a mesophilic and slightly alkaliphilic haloarchaeon, whose optimal growth temperature and pH were 37 °C and pH 8.0–9.0. Phylogenetic analysis based on 16S rRNA gene sequence analysis suggested that strain YSM-123T is a member of the phylogenetic group defined by the family Halobacteriaceae, but there were low similarities to type strains of other genera of this family (≤90 %); for example, Halococcus (similarity <89 %), Halostagnicola (<89 %), Natronolimnobius (<89 %), Halobiforma (<90 %), Haloterrigena (<90 %), Halovivax (<90 %), Natrialba (<90 %), Natronobacterium (<90 %) and Natronococcus (<90 %). The G+C content of the DNA was 63 mol%. Polar lipid analysis revealed the presence of phosphatidylglycerol, phosphatidylglycerophosphate methyl ester, disulfated diglycosyl diether and an unknown glycolipid. On the basis of the data presented, we propose that strain YSM-123T should be placed in a new genus and species, Natronoarchaeum mannanilyticum gen. nov., sp. nov. The type strain of Natronoarchaeum mannanilyticum is strain YSM-123T (=JCM 16328T =CECT 7565T).

Salarchaeum japonicum gen. nov., sp. nov., an aerobic, extremely halophilic member of the Archaea isolated from commercial salt

Strain YSM-79(T) was isolated from commercial salt made from seawater in Yonaguni island, Okinawa, Japan. The strain is an aerobic, Gram-negative, chemo-organotrophic and extremely halophilic archaeon. Cells are short rods that lyse in distilled water. Growth occurs at 1.5-5.3 M NaCl (optimum 2.5-3.0 M), pH 5.0-8.8 (optimum pH 5.2-6.3) and 20-55 °C (optimum 40 °C). Mg²⁺ is required for growth, with maximum growth at 200-300 mM Mg²⁺. Polar lipid analysis revealed the presence of phosphatidylglycerol, phosphatidylglycerophosphate methyl ester, sulfated diglycosyl diether-1 and five unidentified glycolipids. The G+C content of the DNA was 64 mol%. On the basis of 16S rRNA gene sequence analysis, strain YSM-79(T) was determined to be a member of the family Halobacteriaceae, with the closest related genus being Halobacterium (94 % sequence identity). In addition, the rpoB' gene sequence of strain YSM-79(T) had <88 % sequence similarity to those of other members of the family Halobacteriaceae. The results of phenotypic, chemotaxonomic and phylogenetic analysis suggested that strain YSM-79(T) should be placed in a new genus, Salarchaeum gen. nov., as a representative of Salarchaeum japonicum sp. nov. The type strain is YSM-79(T) ( = JCM 16327(T)  = CECT 7563(T)).