Utilization of -xylose as carbon source for production of bacterial cellulose

Utilization of -xylose as carbon source for production of bacterial cellulose was studied. Seventeen strains of acetic acid bacteria were screened for their cellulose productivity in -glucose, -xylose, and -xylose/ -xylulose mixed media, respectively. -Xylose was not well metabolized by any bacterial strains that exhibited high cellulose production in -glucose medium. Consequently, bacterial cellulose production in -xylose medium was unsuccessful. -Xylose, however, became utilizable substrate for bacterial strains if xylose-isomerase was added to the medium. Acetobacter xylinus IFO 15606 was the best cellulose producer in -xylose/ -xylulose mixed medium, so cultural conditions were studied for enhanced cellulose production. With pH controlled, the strain could produce cellulose at a yield exceeding 0.3 g per 100 ml of -xylose/ -xylulose mixed medium, which was comparable to the yields in -glucose medium by excellent producers in the literature.     

Rapid seasonal adaptation of an alien bruchid after introduction: geographic variation in life cycle synchronization and critical photoperiod for diapause induction

Whether alien insects that are introduced into temperate regions adapt to seasonally changing environmental conditions is an important question in evolutionary biology. If rapid evolution has occurred in a non‐native environment, a latitudinal cline in critical photoperiod for diapause induction (i.e., the photoperiod at which half of the individuals enter diapause) and in life cycle synchronization with host plant phenology should be evident among locations. The alien bruchid Acanthoscelides pallidipennis (Motschulsky) (Coleoptera: Bruchidae) is native to North America and introduced into Japan with the host plant Amorpha fruticosa L. (Fabaceae) in the late 1940s. To examine whether seasonal adaptation has occurred in A. pallidipennis, we conducted a laboratory experiment and phenological observations using three latitudinally different populations. We bred F1 eggs at 22 °C and five photoperiodic regimens – L:D = 10:14, 13:11, 14:10, 15:9, or 16:8 hours – and examined whether diapause was induced. The estimated critical photoperiod for diapause induction was longest in the most northern population and shortest in the most southern population. Life cycle was found to be synchronized with host phenology in each location. Also voltinism varied geographically, from univoltine in the northern population to bivoltine in the southern populations. These results showed that A. pallidipennis rapidly adapted to seasonal environmental conditions in Japan after its introduction.     

Coordination of motilin and ghrelin regulates the migrating motor complex of gastrointestinal motility in Suncus murinus

Motilin and ghrelin are the gastrointestinal (GI) hormones released in a fasting state to stimulate the GI motility of the migrating motor complex (MMC). We focused on coordination of the ghrelin/motilin family in gastric contraction in vivo and in vitro using the house musk shrew (Suncus murinus), a ghrelin- and motilin-producing mammal. To measure the contractile activity of the stomach in vivo, we recorded GI contractions either in the free-moving conscious or anesthetized S. murinus and examined the effects of administration of motilin and/or ghrelin on spontaneous MMC in the fasting state. In the in vitro study, we also studied the coordinative effect of these hormones on the isolated stomach using an organ bath. In the fasting state, phase I, II, and III contractions were clearly recorded in the gastric body (as observed in humans and dogs). Intravenous infusion of ghrelin stimulated gastric contraction in the latter half of phase I and in the phase II in a dose-dependent manner. Continuous intravenous infusion of ghrelin antagonist (d-Lys3-GHRP6) significantly suppressed spontaneous phase II contractions and prolonged the time of occurrence of the peak of phase III contractions. However, intravenous infusion of motilin antagonist (MA-2029) did not inhibit phase II contractions but delayed the occurrence of phase III contractions of the MMC. In the in vitro study, even though a high dose of ghrelin did not stimulate contraction of stomach preparations, ghrelin administration (10(-10)-10(-7) M) with pretreatment of a low dose of motilin (10(-10) M) induced gastric contraction in a dose-dependent manner. Pretreatment with 10(-8) M ghrelin enhanced motilin-stimulated gastric contractions by 10 times. The interrelation of these peptides was also demonstrated in the anesthetized S. murinus. The results suggest that ghrelin is important for the phase II contraction and that coordination of motilin and ghrelin are necessary to initiate phase III contraction of the MMC.     

Crystal structure of a GH1 β‐glucosidase from Hamamotoa singularis

A GH1 β‐glucosidase from the fungus Hamamotoa singularis (HsBglA) has high transgalactosylation activity and efficiently converts lactose to galactooligosaccharides. Consequently, HsBglA is among the most widely used enzymes for industrial galactooligosaccharide production. Here, we present the first crystal structures of HsBglA with and without 4′‐galactosyllactose, a tri‐galactooligosaccharide, at 3.0 and 2.1 Å resolutions, respectively. These structures reveal details of the structural elements that define the catalytic activity and substrate binding of HsBglA, and provide a possible interpretation for its high catalytic potency for transgalactosylation reaction.     

Molecular identification of intestinal microflora in Takifugu niphobles

We investigated the intestinal microflora of coastal fish including Takifugu niphobles using both culture techniques and library cloning. As a result, the numbers of bacteria appeared on agar media were 1.0 × 10⁴ to 1.4 × 10⁹ CFU/g (colony forming units/gram), whereas those of total bacteria stained with 4′,6-diamidino-2-phenylindole were 4.7 × 10¹⁰ to 1.9 × 10¹¹ cells/gram, irrespective of different fish species. In addition, the culture technique showed that the intestinal microflora in all specimens was mainly composed of the genus Vibrio. In contrast, the direct count method showed that spirochaetes with length of 2.5-4.5 μm were present in the intestinal contents of T. niphobles at high densities, whereas such bacteria could not be detected in those of other fish species. Library cloning yielded the sequences of 16S rRNA genes that were divided into seven taxonomic categories of bacteria including Actinobacteria, Bacilli, Clostridia, Gammaproteobacteria, Mollicutes, Spirochaetes and an unclassified bacterial group. These results demonstrate that the molecular diversity of the intestinal bacteria in T. niphobles based on the clone library method reflects the direct observation by fluorescence microscopy to some extent.     

Partenskyella glossopodia (Chlorarachniophyceae) possesses a nucleomorph genome of approximately 1 Mbp

The nucleomorph genome size of the recently described chlorarachniophyte Partenskyella glossopodia, which forms an independent lineage in the phylogeny of chlorarachniophytes, was analyzed by pulse‐field gel electrophoresis and Southern hybridization. These analyses showed that the nucleomorph genome of P. glossopodia is composed of three linear chromosomes that are about 445 kbp, 313 kbp, and 275 kbp in size. Thus, the total genome size is approximately 1033 kbp, which is significantly larger than the known size of chlorarachniophyte nucleomorph genomes, i.e. 330–610 kbp. This is the first study to report a nucleomorph genome that reaches approximately 1 Mbp in size.     

Comparison between integrated backscatter intravascular ultrasound and 64-slice multi-detector row computed tomography for tissue characterization and volumetric assessment of coronary plaques

ABSTRACT: BACKGROUND: The purpose of this study was to determine the cut-off values of Hounsfield units (HU) for the discrimination of plaque components and to evaluate the feasibility of measurement of the volume of plaque components using multi-detector row computed tomography (MDCT). Methods: Coronary lesions (125 lesions in 125 patients) were visualized by both integrated backscatter intravascular ultrasound (IB-IVUS) and 64-slice MDCT at the same site. The IB values were used as a gold standard to determine the cut off values of HU for the discrimination of plaque components. Results: Plaques were classified as lipid pool (n =50), fibrosis (n =65) or calcification (n =35) by IB-IVUS. The HU of lipid pool, fibrosis and calcification were 18 +/- 18 HU (-19 to 58 HU), 95 +/- 24 HU (46 to 154 HU) and 378 +/- 99 HU (188 to 605 HU), respectively. Using receiver operating characteristic curve analysis, a threshold of 50 HU was the optimal cutoff values to discriminate lipid pool from fibrosis. Lipid volume measured by MDCT was correlated with that measured by IB-IVUS (r =0.66, p <0.001), whereas fibrous volume was not (r =0.21, p =0.059). Conclusion: Lipid volume measured by MDCT was moderately correlated with that measured by IB-IVUS. MDCT may be useful for volumetric assessment of the lipid volume of coronary plaques, whereas the assessment of fibrosis volume was unstable.     

Shared and separate functions of the RAMP-based adrenomedullin receptors

Adrenomedullin (AM) is a novel hypotensive peptide that exerts a variety of strongly protective effects against multiorgan damage. AM-specific receptors were first identified as heterodimers composed of calcitonin-receptor-like receptor (CLR), a G protein coupled receptor, and one of two receptor activity-modifying proteins (RAMP2 or RAMP3), which are accessory proteins containing a single transmembrane domain. RAMPs are required for the surface delivery of CLR and the determination of its phenotype. CLR/RAMP2 (AM₁ receptor) is more highly AM-specific than CLR/RAMP3 (AM₂ receptor). Although there have been no reports showing differences in intracellular signaling via the two AM receptors, in vitro studies have shed light on their distinct trafficking and functionality. In addition, the tissue distributions of RAMP2 and RAMP3 differ, and their gene expression is differentially altered under pathophysiological conditions, which is suggestive of the separate roles played byAM₁ and AM₂ receptors in vivo. Both AM and the AM₁ receptor, but not the AM₂ receptor, are crucial for the development of the fetal cardiovascular system and are able to effectively protect against various vascular diseases. However, AM₂ receptors reportedly play an important role in maintaining a normal body weight in old age and may be involved in immune function. In this review article, we focus on the shared and separate functions of the AM receptor subtypes and also discuss the potential for related drug discovery. In addition, we mention their possible function as receptors for AM2 (or intermedin), an AM-related peptide whose biological functions are similar to those of AM.     

Variation of the number of proximal caudal vertebrae with tail reduction in Old World monkeys

Tail length in primates can vary greatly between species or even between local conspecific populations, and the tail is markedly reduced in several lineages. In Old World monkeys, tail length is considered as an important feature reflecting their phylogeny and adaptations. The number of caudal vertebrae is one of the important factors which determine tail length, and it is known that this number varies with tail length. Caudal vertebrae can be divided into two types (proximal and distal), and tail mobility and function are considered to be different in these two regions. Though the number of vertebrae in each region is important for understanding tail length evolution in Old World monkeys, there have been few attempts to investigate this matter. This study focused only on the proximal caudal vertebrae, which are more easily preserved than the distal ones, and tested if there is variation in their number with tail length or phylogenic differences. As a result, two important findings were obtained: (1) the variation of the number of proximal caudal vertebrae was different among the phylogenic groups, and (2) especially in Papionini, there was a great variation in the number of proximal caudal vertebrae, and it correlated strongly with relative tail length [RTL = (tail length/head and body length (sitting height)) × 100 %]. I speculate that these variations in the number of proximal caudal vertebrae were possibly caused by a change of the embryonic developmental mechanism of tail morphogenesis, a common mechanism of morphological evolution. To clarify the mechanisms and evolutionary trends of the variation in the proximal caudal vertebrae, not only morphological approaches but also developmental biological approaches will be necessary in the future.