Histology of the pituitary gland of the grey mullet, Mugil cephalus L.

The present communication deals with a histological study of the pituitary gland of the teleost fish Mugil cephalus , found in the estuarine waters of Cochin area. Six different cell types were identified in the pituitary gland on the basis of their grouping, distribution and staining properties. The prolactin and the TSH cells (thyroid stimulating hormone producing cells or thyrotrops) were identified in the rostral pars distalis and the ACTH cells (adrenocorticotropic hormone producing cells or corticotrops) in the interphase between the neurohypophysis and the rostral pars distalis. The STH cells (somatotropic hormone producing cells or somatotrops) and the gonadotropic cells were distinguished in the proximal pars distalis and the MSH cells (melanin stimulating hormone producing cells or melanotrops) in the pars intermedia.     

Metabolism of Yarrowia lipolytica grown on ethanol under conditions promoting the production of alpha-ketoglutaric and citric acids: a comparative study of the central metabolism enzymes

A comparative study of the enzymes of the tricarboxylic acid (TCA) and glyoxylate cycles in the mutant Yarrowia lipolytica strain N1 capable of producing alpha-ketoglutaric acid (KGA) and citric acid showed that almost all enzymes of the TCA cycle are more active under conditions promoting the production of KGA. The only exception was citrate synthase, whose activity was higher in yeast cells producing citric acid. The production of both acids was accompanied by suppression of the glyoxylate cycle enzymes. The activities of malate dehydrogenase, aconitase, NADP-dependent isocitrate dehydrogenase, and fumarase were higher in cells producing KGA than in cells producing citric acid.     

肌苷和鸟苷生产菌中嘌呤核苷合成途径三段基因序列的分析

为了研究肌苷和鸟苷生产菌中与产苷有关的嘌呤核苷合成途径的遗传背景,选择了pur操纵子的启动子序列、编码SAMP合成酶的purA基因和编码GMP合成酶的guaA基因,设计合适的引物,分别从野生菌、一株肌苷低产菌和肌苷鸟苷高产菌中扩增出相应片段,经克隆和测序后,对它们进行比较和分析。分析结果表明两株生产菌的purA基因发生了1个碱基缺失,导致阅读框发生移码突变;而鸟苷高产菌在pur操纵子的启动子部分和操纵子抑制蛋白结合区域发生了近10％的突变,可能影响整个操纵子的表达调控。     

唇形科香茶菜属二萜类化合物分布规律

香茶菜属（Isodon）由于富含二萜类化合物（Diterpenoids）而具有较高的药用价值,本研究根据其所含二萜的骨架和氧化状态,对该类化合物在香茶菜属植物中的分布规律进行研究。UPGMA聚类分析结果显示：含二环和三环二萜为主的植物种类聚在一支上,含四环二萜为主的植物种类聚在另一支上。进一步将二萜分为二环、三环、四环三大类绘制到分子系统树上结果显示：三环二萜主要分布在较原始的类群中,如：线纹香茶菜（I.lophanthoides）和小花线纹香茶菜（I.lophanthoides var. micranthus）;而四环二萜主要分布在较进化的类群中,如：旱生香茶菜（I.xerophilus）和腺花香茶菜（I.adenanthus）。本研究通过对二萜类化合物与香茶菜属系统发育之间存在的联系进行探讨,有助于对香茶菜属植物中的二萜类化合物活性成分进行筛选与研发。     

Higher Isolation of NDM-1 Producing Acinetobacter baumannii from the Sewage of the Hospitals in Beijing

Multidrug resistant microbes present in the environment are a potential public health risk. In this study, we investigate the presence of New Delhi metallo-β-lactamase 1 (NDM-1) producing bacteria in the 99 water samples in Beijing City, including river water, treated drinking water, raw water samples from the pools and sewage from 4 comprehensive hospitals. For the bla _NDM-1 positive isolate, antimicrobial susceptibility testing was further analyzed, and Pulsed Field Gel Electrophoresis (PFGE) was performed to determine the genetic relationship among the NDM-1 producing isolates from sewage and human, as well as the clinical strains without NDM-1. The results indicate that there was a higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals, while no NDM-1 producing isolates were recovered from samples obtained from the river, drinking, or fishpond water. Surprisingly, these isolates were markedly different from the clinical isolates in drug resistance and pulsed field gel electrophoresis profiles, suggesting different evolutionary relationships. Our results showed that the hospital sewage may be one of the diffusion reservoirs of NDM-1 producing bacteria.     

Characterization of enterocin- and salivaricin-producing lactic acid bacteria from the mammalian gastrointestinal tract

Bacteriocin production may be a factor contributing to bacterial dominance within complex microbial populations and may therefore be a common trait within the gut microbiota. However, of 278 antimicrobial-producing culturable lactic acid bacteria (LAB) isolated from a range of mammalian intestinal sources in this study, characterization revealed just 23 distinct strains producing bacteriocin-like inhibitory substances and one Streptococcus hyointestinalis strain producing a potentially novel protease-insensitive antimicrobial. Three class II bacteriocins previously isolated from intestinal-derived LAB were identified as enterocin A and two salivaricin P-like bacteriocins. Moreover, this is the first report of intestinal-derived Streptococcus salivarius producing variants of the lantibiotic salivaricin A.     

新疆尉犁县黑湖嗜盐嗜碱菌的分离及系统发育学分析

【目的】从新疆尉犁县黑湖中筛选分离获得嗜盐嗜碱微生物,并对筛选获得的微生物进行种属鉴定。【方法】采用传统分离鉴定技术,进行形态和生理生化特性研究和基于16S r RNA基因的序列分析。【结果】从样品中分离获得可培养嗜盐嗜碱菌25株,对其进行鉴定。根据生理生化特征、16S r RNA基因序列测定和系统发育分析表明,25株菌分布在古菌Halorubrum、Haloarcula、Natrialba、Halohasta和Halopiger等5个属。其中优势菌群为Halorubrum,次优势菌群为Natrialba。其中DH-66(KU663028)属于Halopiger属,16S r RNA基因序列同源性与该属的模式菌株Halopiger aswanensis 56T同源性最高,为95.75%,预示为潜在的新种(新种鉴定将另行报道)。25株嗜盐嗜碱菌生长条件实验表明,这些菌适应Na Cl的浓度范围为15%-30%、最适浓度为20%-25%,生长的p H范围为7.0-13.0、最适p H为9.0-10.0。各种水解酶类的分析表明,在分离的25株菌中产淀粉酶的菌有5株占20%、产蛋白酶的菌有4株占16%、产酯酶可水解吐温20的菌有15株占60%、可水解吐温40的有7株占28%、可水解吐温80的有4株占16%、产过氧化氢酶的菌有14株占56%。9株菌同时能产4种酶,2株菌同时能产3种酶。表明了嗜盐嗜碱菌产酶的多样性。19株菌硝酸盐还原为阳性。【结论】揭示了新疆尉犁县黑湖嗜盐嗜碱菌生理生化特性的多样性和系统发育多样性,而且蕴藏着较丰富的新的微生物类群,亟待系统研究和进一步开发利用。     

Cantharidin world on islands: Species diversity of canthariphilous arthropods in the Izu–Ogasawara Arc

Cantharidin is a defense chemical produced by only two beetle families, Meloidae and Oedemeridae. This compound also functions as an attractant for certain groups of arthropods (canthariphilous arthropods). Cantharidin‐producing beetles and canthariphilous arthropods build a cantharidin‐mediated community, called cantharidin world. In this study, to clarify the canthariphilous arthropod community formed on small islands, the arthropods were collected by cantharidin‐baited traps and compared among the mainland, peninsula and 11 small islands of the Izu–Ogasawara Arc, Japan. Control traps without cantharidin were also used to collect non‐canthariphilous arthropods. Cantharidin‐producing beetles were distributed across the study area, but the number of species was reduced on islands. We identified 10 species of five families as canthariphilous arthropods in this study area: two species of Anthicidae and Pyrochroidae (Coleoptera), four species of Ceratopogonidae (Diptera), three species of Formicidae (Hymenoptera) and one species of Podoctidae (Opiliones). The number of canthariphilous species was not correlated with island size (area) but was negatively correlated with the distance of island from the mainland. These tendencies were also seen in non‐canthariphilous fauna. The canthariphilous arthropods increased with the number of cantharidin‐producing beetle species, but the non‐canthariphilous fauna did not. Thus, the cantharidin world on islands seems to be affected not only by the geographic characteristics of islands, particularly the degree of isolation from the mainland, but also by the diversity of cantharidin‐producing members within it.     

Circulating Interferon Production in the Mouse : Origin and nature of cells involved and influence of animal genotype

A radiobiological study of circulating interferon production in the mouse was undertaken in the hope of elucidating the site(s) of circulating interferon production. After total body X-irradiation of the animals, different radiosensitivities of circulating interferon production were observed with different viral inducers. Myxovirus-induced circulating interferon production was especially radiosensitive. Moreover, a study of interferon production in syngeneic and xenogeneic radiochimeras demonstrated that cells producing NDV (Newcastle disease virus)-induced circulating interferon were derived from hematopoietic stem cells. In addition, treatment of mice with antilymphocyte serum significantly reduced NDV- and Sendai virus-induced circulating interferon, as opposed to other inducers. Taken together, these results strongly suggest that the lymphocyte is the major source of myxovirus-induced circulating interferon. A survey of interferon production in 12 inbred mouse strains, using NDV as inducer, revealed the existence of low and high producers. A Mendelian analysis carried out with low producing Balb/c and high producing C57BL indicated that the difference between low and high interferon producers was caused by a single, autosomal, codominant factor.     

乳链菌肽(nisin)抗性机制的研究进展

乳链菌肽(nisin)是某些乳酸乳球菌产生的一种羊毛硫细菌素。其对包括食品腐败菌和致病菌在内的许多革兰氏阳性菌具有强烈的抑制作用,是目前世界上唯一被允许用作食品添加剂的细菌素。nisin的广泛使用虽未引发大范围的抗性,但在自然界或实验室的选择压力下,某些非nisin产生菌也获得了抵御nisin攻击的抗性机制。nisin抗性机制通常涉及两种方式,即非特异性的生理适应机制和特异性蛋白酶介导的主动防御机制。本文综述了近年来nisin抗性机制的研究进展。     

Comparative analysis of the major protective antigens production in Vibrio cholerae recombinant and producer strains of the classical biovar

The comparative study of 4 constructed protective antigen producing strains of the classical biovar and V. cholerae strains 569 B Inaba and M41 Ogawa, used in manufacturing the cholera chemical vaccine "cholerogen-toxoid", was carried out. The study revealed that V. cholerae plasmid strains 2414 Ogawa, 2415 Inaba and nonplasmid strains 2416 Ogawa, 2417 Inaba had a higher level of production of the main protective antrigens in comparison with producer strains. They also synthesized much more (4-5 fold) cholera toxin, toxin co-regulated adhesion pili, contained protein OmpU in their outer membrane, exceeded 2- to 3-fold in the synthesis of pathogenicity enzymes (proteases, phospholipases) and synthesized the same amounts of 01 antigen, serovars Inaba and Ogawa. The use of the newly created protective-antigen producing strains in vaccine manufacturing could facilitate the preparation of a more effective cholera chemical vaccine "cholerogen-toxoid".     

Recycling of cooking oil fume condensate for the production of rhamnolipids by Pseudomonas aeruginosa WB505

Bioprocess and Biosystems Engineering - Rhamnolipids (RLs) are anionic biosurfactants with great application potential. This study explored the possibility of producing RLs from cooking oil fume...     

Isolation of tannase‐producing microbiota from the gastrointestinal tracts of some freshwater fish

Tannins are the most abundant among the plant‐derived antinutrients that bind readily with protein and other macromolecules to form indigestible complexes, thereby reducing the nutritional value of the plant feedstuffs. Presence of tannase‐producing gut microbiota in herbivorous animals has been suggested to overcome the antinutritional effects of tannins. However, this topic has been less investigated in herbivorous/omnivorous fish species. The present study was undertaken to evaluate the presence of tannase‐producing autochthonous microbiota in the gastrointestinal (GI) tracts of some culturable freshwater teleosts and to identify most promising tannase‐producing strains by molecular methods. Isolation and enumeration of tannase‐producing autochthonous microbiota have been carried out in the gut of ten culturable freshwater teleosts, namely catla (Catla catla), silver carp (Hypophthalmichthys molitrix), rohu (Labeo rohita), grass carp (Ctenopharyngodon idella), mrigal (Cirrhinus mrigala), common carp (Cyprinus carpio), bata (Labeo bata), kalbasu (Labeo calbasu), tilapia (Oreochromis mossambicus), and Nile tilapia (Oreochromis niloticus). Culturable heterotrophic and tannase‐producing microbial populations evaluated on tryptone soya agar and selective tannic acid agar media, respectively, revealed the maximum in the hindguts of all fish species studied. Out of 72 tannase‐producing colonies, 18 randomly selected isolates were maintained as pure cultures and evaluated quantitatively for tannase production. Among these, four most promising tannase producers were identified by 16S/26S rDNA sequencing following nucleotide blast and deposited in the National Centre for Biotechnology Information (NCBI) GenBank. The strain LR01 isolated from rohu was a bacterium, Enterobacter asburae (GenBank Accession No. GU939631 ). However, the strains CM02, OM01 and LR03 isolated from mrigal, tilapia and rohu were yeasts and identified as Pichia kudriavzevii (GenBank Accession No. GU939629 ), Candida tropicalis (GenBank Accession No. GU911469 ) and Candida parapsilosis (GenBank Accession No. GU939630 ), respectively. To the authors' knowledge, the present study is the first to report tannase‐producing autochthonous microbiota in the gut of freshwater teleosts. Tannin‐degrading microbiota detected in the present study may endow the fish with some ecological advantages by enabling them to overcome the anti‐nutritional effects of plant tannins.     

紫杉二烯人工酵母的代谢组学分析

为了更深入地从代谢角度研究萜类合成人工酵母的内在差异,以紫杉二烯人工酵母为例,利用代谢组学的方法对其发酵指数中期胞内代谢物的变化进行了测定。结果表明,与对照菌W303-1A相比,紫杉二烯的生产会对胞内糖酵解、三羧酸循环中间物及一些氨基酸的含量产生不同程度的影响,进而对其生长产生一定抑制作用。其中柠檬酸因紫杉二烯功能模块的引入下降明显,降幅达90%以上,因此可以作为后续功能酵母研究的标志性代谢物。紫杉二烯人工酵母细胞代谢组的研究可以为萜类化合物异源合成的优化提供更多的信息和帮助。     

Selection at the ABO locus in the Japanese population

Hiraizumi et al. (1973b) concluded that maternal-fetal ABO incompatibility effect upon the frequency of prenatal deaths was totally absent in two modern Japanese cities, Ohdate and Akita. However, they found a significant heterogeneity in the frequency of prenatal deaths among 16 mating types and suggested that the viability of A-bearing fetuses was higher than that of others, hence the frequency of prenatal deaths decreased with the increasing probability of producing A-bearing fetuses. Further analyses were performed in the present study and the above suggestion was confirmed. Then, the average numbers of prenatal deaths and pregnancies per couple were analyzed separately for their relationships with the probability of producing an A-bearing fetus. The results were found to be consistent with the model that the average numbers of prenatal losses per couple are approximately the same between two groups of matings, one producing and the other not producing A-bearing fetuses, but such losses occur more frequently for the A-bearing fetuses than others at the very early stage of pregnancy such that wives may not recognize such losses. Although the stages of losses are different between A-bearing and other fetuses, the net losses are nearly the same between them, so that such losses will not be reflected in the segregation frequencies among children, as shown by Hiraizumi et al. (1973a).     

Action of antibiotics on the growth and metabolic processes of streptomycetes and Nocardia

New experimental data on the effect of novobiocin, ristomycin and nystatin on growth and metabolism of Streptomycetes and Nocardia are presented. The study of the organisms producing other antibiotics showed that they were tens, hundreds and even thousands times more sensitive to the tested biologically active compounds than the organisms producing these compounds. The protein synthesis and antibiotic biosynthesis proved to be most sensitive out of the processes studied. The findings showed that during their evolution the antibiotic-producing organisms have developed definite protective mechanisms which enable them to resist relatively high concentrations of their own metabolites (antibiotics). This ensures them in their struggle for existence.     

Comparative characteristics of penicillin-binding proteins of representatives of the genus Streptomyces

Penicillin-binding proteins (PBPs) in Strepomyces strains producing clavulanic acid and beta-lactamase and in Streptomyces strains not producing these compounds were studied comparatively. In S. clavuligerus, the organism producing clavulanic acid, there were detected 3 PBPs in the membrane fraction. S. griseus, the organism producing beta-lactamase, contained 6 PBP. In S. cacaoi and S. olivaceus, organisms producing neither beta-lactams nor beta-lactamase, there were detected 5 and 4 PBP, respectively. The set of the PBP in the organism producing clavulanic acid varied during fermentation. In a variant of S. clavuligerus isolated after protoplasting of the mycelial cells and their regeneration the content of the electrophoretically most mobile PBP lowered. The PBP of S. clavuligerus did no show any high affinity to other beta-lactams such as methicillin and ampicillin tested as competing agents of 14C-benzylpenicillin.     

Establishment of a novel method for the production of chimeric mouse embryos using water-in-oil droplets

Production of chimeric animals is often a necessity for the generation of genetically modified animals and has gained popularity in recent years in regenerative medicine for the reconstruction of xenogeneic organs. Aggregation and injection methods are generally used to produce chimeric mice. In the aggregation method, the chimeras are produced by co-culturing embryos and stem cells, and keeping them physically adhered, although it may not be an assured method for producing chimeric embryos. In the injection method, the chimeras are produced by injecting stem cells into the zona pellucida using microcapillaries; however, this technique requires a high degree of skill. This study aimed to establish a novel method for producing chimeric embryos via water-in-oil droplets that differs from conventional methods. In this study, embryonic stem cells and embryos were successfully isolated in the droplets, and the emergence of chimeric embryos was confirmed by co-culture for 6 h. Using this method, the control and operability of stem cell numbers could be regulated, and reproducibility and quantification were improved during the production of chimeric embryos. In addition to the conventional methods for producing chimeric embryos, the novel method described here could be employed for the efficient production of chimeric animals.     

Penetration of β-lactamase inhibitors into the periplasm of Gram-negative bacteria

The effectiveness of a beta-lactamase inhibitor/beta-lactam combination against Gram-negative pathogens depends on many interplaying factors, one of which is the penetration of the inhibitor across the outer membrane. In this work we have measured the relative penetrations of clavulanic acid, sulbactam, tazobactam and BRL 42715 into two strains of Escherichia coli producing TEM-1 beta-lactamase, two strains of Klebsiella pneumoniae producing either TEM-1 or K-1, and two strains of Enterobacter cloacae each producing a Class C beta-lactamase. It was shown that clavulanic acid penetrated the outer membranes of all these strains more readily than the other beta-lactamase inhibitors. For the strains of E. coli and K. pneumoniae clavulanic acid penetrated approximately 6 to 19 times more effectively than tazobactam, 2 to 9 times more effectively than sulbactam and 4 to 25 times more effectively than BRL 42715. The superior penetration of clavulanic acid observed in this study is likely to contribute to the efficacy of clavulanic acid/beta-lactam combinations in combating beta-lactam resistant bacterial pathogens.     

The effect of stress on interferon production in mice

In order to study the effect of stress on the interferon (IFN) production, we determined the IFN-alpha/beta and -gamma producing capacities in restraint-stressed and SART-stressed mice. Restraint-stress caused not only a significant reduction in body weight, but also a reduction in the weight of spleen. The IFN-alpha/beta producing capacity by Newcastle disease virus (NDV) was significantly lower in the stressed mice. The IFN-gamma producing capacity by both Con-A and PHA-P was also depressed by this stress. On the other hand, SART-stress, whose severity was thought to be mild because no loss of body and spleen weights was seen, did not affect IFN-alpha/beta and -gamma producing capacities. These results suggest that the suppression of IFN producing capacity is dependent on the severity of physical stress.