Identification and characterization of a novel (−)-vibo-quercitol 1-dehydrogenase from Burkholderia terrae suitable for production of (−)-vibo-quercitol from 2-deoxy-scyllo-inosose

Applied Microbiology and Biotechnology - (−)-vibo-Quercitol is a deoxyinositol (1l-1,2,4/3,5-cyclohexanepentol) that naturally occurs in oak species, honeydew honey, wines aged in oak...     

The evolutionary history and taxonomic reevaluation of the Japanese coral snake,Sinomicrurus japonicus (Serpentes,Elapidae), endemic to the Ryukyu Archipelago,Japan, by use of molecular and morphological analyses

Sinomicrurus japonicus has a conspicuous colour pattern of longitudinal black stripes and transverse sets of black and white bands with an orange‐reddish background colour. The pattern varies markedly among island populations, and thus, three subspecies have been recognized. We conducted molecular phylogenetic analyses on the island populations to clarify the evolutionary trajectory of such colour patterns and reevaluate the current classification accordingly. The results indicated relatively deep allopatric divergences within S. j. boettgeri, paraphyly of S. j. boettgeri against other two subspecies, and two independent derivations of S. j. takarai from boettgeri‐like ancestors. Detailed morphological analyses revealed that variations in the boettgeri and takarai forms were more or less continuous and that differences between the two takarai populations were very small. From these results, we propose synonymizing S. j. takarai with S. j. boettgeri. Morphological differences between the genetically most distant populations of S. j. boettgeri were also small, whereas the japonicus form was distinct from the remainder. Considering the possible evolution of S. j. japonicus through peripheral isolation, we propose retention of these two subspecies. This study provides a basis for future work on the adaptive significance of geographic variation in the colour pattern of S. japonicus.     

Identification of Arsenobetaine,a Water Soluble Organo-arsenic Compound in Muscle and Liver of a Shark,Prionace glaucus

After male rats of the Sprague Dawley strain, 5 weeks old, were fed a 20% casein diet for 12 days, 70 mg of streptozotocin/kg body weight (STZ group) or 70 mg of streptozotocin and 500 mg of nicotinamide/kg body weight (STZ-Nam group) was injected intraperitoneally into the rats. The rats were kept for 21 more days on the 20% casein diet and killed by decapitation. Urine was collected for the last 2 days. The level of blood glucose was 2-fold higher in the STZ group than in the STZ-Nam group. Urinary excretion of large amounts of glucose was observed only in the STZ group. Extremely reduction of urinary excretion of nicotinamide was observed in the STZ group, but, urinary excretion of N¹-methylnicotinamide (MNA) and N-¹-methyl-2-pyridone-5-carboxamide (2-py) was about the same in the two groups and that of N¹-methyl-4-pyridone-3-carboxamide (4-py) was higher in the STZ group than in the STZ-Nam group. The sum of urinary excretion of nicotinamide, MNA, 2-py, and 4-py was higher in the STZ group than in the STZ-Nam group. The levels of NAD in liver, pancreas, and blood in the STZ group tended to be higher, or rather not to decrease compared to the STZ-Nam group. For enzyme activities concerned with the tryptophan-NAD metabolism, a marked increase was observed in the activities of aminocarboxymuconate-semialdehyde decarboxylase, 3-hydroxyanthranilic acid oxygenase, and nicotinamide methyltransferase, on the other hand, the activity of NAD⁺ synthetase decreased in the STZ group compared to the STZ-Nam group. The activities of tryptophan oxygenase, kynureninase, NMN adenylyltransferase, and MNA oxidase were about the same in the two groups. These changes in the above enzyme activities mean that the conversion ratio from tryptophan to NAD is lower in the streptozotocin diabetic rats than normal rats, but the tryptophan metabolites such as NAD and 4-py were higher in the STZ group than in the STZ-Nam group. This might be due to the higher food intake and the lower body weight gain in the STZ group than in the STZ-Nam group. Similar phenomena have reported in alloxan diabetic rats.     

贵州省喀斯特地区原始林水化学特征

降水是森林生态系统的一个主要的养分输入源,观测并分析降水化学对于准确地估算森林生态系统养分循环的养分元素浓度与量显得极为重要。对贵州省茂兰国家自然保护区原始林森林群落2007年9月-2008年8月的降水进行定位观测与分析。结果表明:(1)在林外雨、林内雨、树干流和溪流水中,除了Na+之外,pH值与大部分的养分元素的浓度表现出明显的季节变化,冬季与早春浓度较高,夏季浓度较低。这与各季节的降雨量不同而导致浓度稀释或者浓缩有关。(2)大气降雨通过林冠的过程中,养分元素的浓度出现了较大的变化,林内雨与树干流中的浓度基本高于大气降雨;养分元素变化中,浓度差异较大的元素是K+、Mg2+和Ca2+,K+在林内雨和树干流的浓度分别是大气降雨的14倍和21倍;Mg2+浓度分别为大气降雨的12倍和9倍;Ca2+浓度分别为大气降雨的4倍和3倍,这与大气降雨通过林冠,与树体的养分交换以及树体养分的溶脱有关。(3)通过林内雨,树干流输入样地较多的养分元素是K+和Ca2+,分别是35.8kg.hm-.2a-1和31.5kg.hm-.2a-1;通过溪流水输出的元素中,较多的是Ca2+和Mg2+,分别是-547.4kg.hm-.2a-1和-144.5kg.hm-.2a-1;其次是SO24-,而Na++K++NH4+-N总量不足阳离子总量的1%,Cl-+NO3-总量不足阴离子总量的1%。这可能与母岩风化是碳酸岩类岩石风化有关。(4)年养分的垂直移动量特征显示,土壤0cm到土壤5cm的养分元素量变化较明显,无机态N量的变化可能跟微生物的氮固定、无机化或者植被的吸收有关。(5)研究地的年间养分元素量收支分别为N2.9kg.hm-.2a-1;K25.2kg.hm-.2a-1;Ca-547.4kg.hm-.2a-1;Mg-144.5kg.hm-.2a-1;Na-4.0kg.hm-.2a-1;Cl2.5kg.hm-.2a-1和SO24-S-5.9kg.hm-2.a-1。在年间养分的输入与输出中,无机态N跟K+显示正收支,Ca2+、Mg2+为负收支,而Na+、Cl-相对较稳定。     

Water-soluble chlorophyll protein of Brassica oleracea var. Botrys (cauliflower)

A water-soluble chlorophyll protein was prepared from Brassica oleracea var. Botrys (cauliflower) and purified by (NH₄)₂SO₄ fractionation and by chromatography on a DEAE-cellulose column. The chlorophyll protein contained chlorophylls a and b in the ratio 6:1, and no carotenoids. The molecular weight, determined by means of gel filtration on Sephadex G-100, was 78000. The chlorophyll protein showed absorption peaks at 273, 340, 384, 420, 438, 465, 628, 674 and 700 nm. Since the three bands at 384, 420 and 438 nm all have approximately the same height, the spectrum is different from that of chlorophyll a in organic solvents. The fluorescence of the chlorophyll protein showed a peak at 683 nm, with shoulders at 706 and 745 nm at room temperature, and peaks at 685, 706 and 744 nm at the temperature of liquid N₂. An apo-protein was prepared by removing the chlorophylls with 2-butanone and purified by precipitation with (NH₄)₂SO₄. The apo-protein thus prepared had an absorption band at 273 nm but none at longer wavelengths. The apo-protein could be combined with chlorophylls, forming a chlorophyll protein which had spectral characteristics similar to those of the original.     

Development of polyspermic zygote and possible contribution of polyspermy to polyploid formation in angiosperms

Fertilization is a general feature of eukaryotic uni- and multicellular organisms to restore a diploid genome from female and male gamete haploid genomes. In angiosperms, polyploidization is a common phenomenon, and polyploidy would have played a major role in the long-term diversification and evolutionary success of plants. As for the mechanism of formation of autotetraploid plants, the triploid-bridge pathway, crossing between triploid and diploid plants, is considered as a major pathway. For the emergence of triploid plants, fusion of an unreduced gamete with a reduced gamete is generally accepted. In addition, the possibility of polyspermy has been proposed for maize, wheat and some orchids, although it has been regarded as an uncommon mechanism of triploid formation. One of the reasons why polyspermy is regarded as uncommon is because it is difficult to reproduce the polyspermy situation in zygotes and to analyze the developmental profiles of polyspermic triploid zygotes. Recently, polyspermic rice zygotes were successfully produced by electric fusion of an egg cell with two sperm cells, and their developmental profiles were monitored. Two sperm nuclei and an egg nucleus fused into a zygotic nucleus in the polyspermic zygote, and the triploid zygote divided into a two-celled embryo via mitotic division with a typical bipolar microtubule spindle. The two-celled proembryos further developed and regenerated into triploid plants. These suggest that polyspermic plant zygotes have the potential to form triploid embryos, and that polyspermy in angiosperms might be a pathway for the formation of triploid plants.     

Reactivity in human cerebral artery: species variation

It is becoming obvious that the reactivity of vascular smooth muscle to vasoactive agents is not homogeneous in different arteries (cerebral vs. other arteries) from the same animal species or in cerebral arteries from different species. In this communication, the reactivity of human cerebral arteries to norepinephrine (NE), dopamine (DA), small amounts of K+ and ouabain and their mechanisms of action are compared with those in monkey and dog cerebral arteries. NE produces moderate contractions in the primate arteries, mediated by alpha 1 adrenoceptors, and slight contractions in the dog arteries, possibly mediated by alpha 2 receptors. DA relaxes human and monkey cerebral arteries but contracts the dog arteries. The primate artery relaxation mediated by dopaminergic receptors is large enough to predominate over the alpha 1 receptor-mediated contraction. Minute amounts of K+ preferentially relax cerebral arteries from humans, monkeys, and dogs, possibly activating the electrogenic Na+ pump. Ouabain, a Na+ pump inhibitor, contracts these cerebral arteries with low concentrations. Human and monkey cerebral arteries respond similarly to vasoactive agents presented so far, and appear to share the same mechanisms of action; however, the responsiveness of dog cerebral arteries differs.     

Improved technique for the gut fluorescence method in a feeding study of small zooplankton

An Increase in the sensitivity of chlorophyll pigment analysiswas provided by small-volume quartz cuvettes with a specialholder for the determination of gut chlorophyll pigment in anindividual small zooplankton.