Heterologous Expression and Characterization of L-Amino Acid Deaminase from Proteus mirabilis in Escherichia coli

We expressed an L-amino acid deaminase (Pma) from Proteus mirabilis (P. mirabilis) in Escherichia coli and characterized the kinetics of phenylpyruvic acid production. P. mirabilis Pma was well expressed in E. coli in an active state and was found to be associated with membranes. The association of Pma with cellular membranes is likely to be necessary for its enzymatic activity.     

Effect of the proteolytic enzymes of Bacillus licheniformis and the lysoamidase of Lysobacter sp. XL1 on Proteus vulgaris and Proteus mirabilis

Preparations of culture liquid of three Bacullus licheniformis strains (S, 103, and 60.4) and the enzymatic preparation lysoamidase from culture liquid of Lysobacter sp. strain XL1 actively lysed preliminarily autoclaved cells of gram-negative bacteria Proteus vulgaris and P. mirabilis. Living Proteus cells treated with these enzymatic preparations were lysed during their subsequent autoclaving. Inoculation of enzyme-treated Proteus cells, taken either separately or in combination with one another and polymyxin B, into a rich medium led to cell repair and restoration of viability of culture.     

Settlement inhibition of fouling invertebrate larvae by metabolites of the marine bacterium halomonas marina within a polyurethane coating

The marine bacterium, Halomonas marina (ATCC 27129), was shown to inhibit settlement and development of the sessile invertebrates Balanus amphitrite and Bugula neritina. Different bacterial treatments were employed to investigate this interaction. Filmed bacteria and liquid suspensions of whole cells, lysed cells and culture filtrate all reduced settlement of B. amphitrite. Polyurethane coatings containing whole cells were partially inhibitory while lysed cells caused complete inhibition of B. amphitrite larval settlement. In contrast, culture filtrate in a polyurethane matrix stimulated settlement of B. amphitrite larvae. Whole cells, culture filtrate, and lysed cells embedded in a polyurethane coating also controlled B. neritina settlement and maturation.     

The structure of the carbohydrate backbone of the core–lipid A region of the lipopolysaccharide from Proteus penneri strain 40: new Proteus strains containing open-chain acetal-linked N-acetylgalactosamine in the core part of the LPS

Analysis of the core part of the LPS from several strains of Proteus revealed that P. penneri strains 2, 11, 19, 107, and P. vulgaris serotypes O4 and O8 have the same structure with a new type of linkage between monosaccharides–an open-chain acetal — that was previously determined for P. vulgaris OX2 and P. penneri 17. The LPS from P. penneri strain 40 contains the same structure substituted with one additional monosaccharide:

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where (1S)-GalaNAc¹ is a residue of N-acetyl- -galactosamine in the open-chain form. It is connected as a cyclic acetal to positions 4 and 6 of the galactosamine residue having a free amino group. All other sugars are in the pyranose form.     

Lytic Enzyme toward Aniline-assimilating Rhodococcus erythropolis AN-13: Screening and Production

A bacterial strain, SH-548, that produces a lytic enzyme toward intact cells of aniline-assimilating Rhodococcus erythropolis AN-13, was isolated from soil. The isolated bacterium was identified as a Flavobacterium species. The growth conditions for the enzyme production by Flavobacterium sp. SH-548 were examined; organic nitrogen compounds, such as meat extract and Polypepton, were effective for its production. The lytic enzyme of this strain lysed intact cells of Rhodococcus, Bacillus, Nocardia, Corynebacterium, Brevibacterium, Streptococcus, Micrococcus, Cellulomonas and DAB (diaminobutyric acid)-type coryneform bacterial strains. However, it did not act on those of Staphylococcus aureus or gram-negative bacteria, Enterobacter, Escherichia, Klebsiella, Proteus or Pseudomonas strains. Bacterial strains having cell walls of the glycolyl type were readily lysed by this enzyme.     

Interspecies recA protein substitution in Escherichia coli and Proteus mirabilis

Summary With the help of recombinant plasmids carrying the recA gene of Escherichia coli or of Proteus mirabilis the ability of the recA gene products to substitute functionally for each other was studied. The recA protein of each can function in recombination, repair, induction of mutations and prophages and in regulation of its own synthesis within the foreign host nearly equally well as in the natural host. It is, therefore, suggested that recA-dependent processes act similarly in E. coli and P. mirabilis.     

奇异变形杆菌毒力因子的研究进展

奇异变形杆菌是革兰阴性细菌,在自然界中广泛存在,具有特殊的群集运动能力,与临床关系密切,可在膀胱和肾脏中形成结石,在尿道留置管外表面、内腔中形成结晶生物膜,是引起复杂尿路感染的主要病原体,主要的毒力因子包括菌毛、黏附素、尿素酶、溶血素、金属摄取和免疫逃避等。综述了近年来有关奇异变形杆菌毒力因子的研究,为相关研究提供参考。     

Functional substitution of the recE gene of Bacillus subtilis by the recA gene of Proteus mirabilis

Summary Rec mutants of Bacillus subtilis have been tested for complementation by the recA gene of Proteus mirabilis (recApm) which was introduced into B. subtilis via the plasmid pHP334. In the recE4 mutant of B. subtilis the plasmid pHP334 restored significantly the defects in RecE functions tested: UV-sensitivity, homologous recombination (transduction and transformation) and prophage induction.Although serological methods to detect the presence of RecApm protein in B. subtilis have been unsuccessful, our results strongly indicate that the recE function of B. subtilis is analogous to the recA function of P. mirabilis.Abbreviations Cm^r resistance to chloramphenicol - Em^r resistance to erythromycin - Tc^r resistance to tetracycline - SDS sodium dodecyl sulfate - UV ultraviolet - AS ammonium sulfate     

Marine Fungi Aspergillus sydowii and Trichoderma sp. Catalyze the Hydrolysis of Benzyl Glycidyl Ether

Whole cells of the marine fungi Aspergillus sydowii Gc12, Penicillium raistrickii Ce16, P. miczynskii Gc5, and Trichoderma sp. Gc1, isolated from marine sponges of the South Atlantic Ocean (Brazil), have been screened for the enzymatic resolution of (±)-2-(benzyloxymethyl)oxirane (benzyl glycidyl ether; 1). Whole cells of A. sydowii Gc12 catalyzed the enzymatic hydrolysis of (R,S)-1 to yield (R)-1 with an enantiomeric excess (ee) of 24–46% and 3-(benzyloxy)propane-1,2-diol (2) with ee values <10%. In contrast, whole cells of Trichoderma sp. Gc1 afforded (S)-1 with ee values up to 60% and yields up to 39%, together with (R)-2 in 25% yield and an ee of 32%. This is the first published example of the hydrolysis of 1 by whole cells of marine fungi isolated from the South Atlantic Ocean. The hydrolases from the two studied fungi exhibited complementary regioselectivity in opening the epoxide ring of racemic 1, with those of A. sydowii Gc12 showing an (S) preference and those of Trichoderma sp. Gc1 presenting an (R) preference for the substrate.     

Partial purification and characterization of an initiation protein for germination from Clostridium perfringens spores

An initiation protein which promoted genermination of dithiothreitol-sodium dodcyl suflate-trated spores of clostridium perfringens was purified from 7-h culture supernatant fluid of cell of Cl. perfringenes. A 3100-fold purification was obtained after cellulose-phosphate and Sephadex G-100 chromatography. The isolated product had an apparent molecular weight of 100 000, an isoelectric point of 7.9, was reversibly inhibited by HgCl₂ and lysed isolated cortical fragments from Cl. perfringens spores.     

Antibacterial activity of cyclodextrins against <Emphasis Type="Italic">Bacillus</Emphasis> strains

Growth of alkaliphilic Bacillus halodurans C-125 both on agar plates and in liquid culture was inhibited by methyl-β-cyclodextrin (CD). Furthermore, resting cells of the strain were lysed by contact with methyl-β-CD higher than 10 mM. α-CD also showed lysis activity against Bacillus and related strains. The activity was not observed with Gram-negative and Gram-positive bacteria except for Bacillus strains. Fluorescence staining and scanning electron microscopy of cells revealed that methyl-β-CD disrupted cell membranes, and consequently, the cells were lysed. This is a novel physiological property of CDs.     

Isolation and characterization of a novel chytrid species (phylum Blastocladiomycota), parasitic on the green alga Haematococcus

A parasite was found in cultures of the green microalga Haematococcus pluvialis that grew epibiotically on algal cells and caused epidemics resulting in damage to the host cultures. The parasite was isolated into axenic culture on solid and liquid media. It was demonstrated to be the sole causative agent of the epidemics. According to its life cycle and phylogenetic analysis based on 18S ribosomal DNA sequences, the pathogen appears to represent a novel chytrid fungus closely related to the vascular plant pathogen Physoderma (Blastocladiomycota), although it differs from all other known chytrids by its infective stage, a wall-less propagule endowed with amoeboid motion and lacking the group's typical flagellum.     

Somatic embryogenesis in the Panax ginseng cell culture induced by the rolC oncogene is associated with increased expression of WUS and SERK genes

The embryogenic cell culture 2c3 was previously obtained by the transfer of the rolC gene from Agrobacterium rhizogenes into ginseng callus cells. It was found by us that the expression of SERK and WUS genes in the embryogenic culture 2c3 is increased. These genes are known to be responsible for the initial stimulus to the development of embryogenesis in plants. Taking into consideration earlier data, we suppose that the development of somatic embryos in the ginseng cell culture 2c3 is associated with changes in the work of the calcium signaling system and with the activation of expression of SERK and WUS genes. Original Russian Text ? K.V. Kiselev, G.K. Tchernoded, 2009, published in Genetika, 2009, Vol. 45, No. 4, pp. 511–518.     

长春地区鸡源奇异变形杆菌的分离鉴定及毒力分析

【背景】奇异变形杆菌(Proteus mirabilis)是一种机会致病菌,广泛存在于周围环境中,常导致动物和人类感染。【目的】探究吉林省长春地区某养鸡场病鸡死亡原因,为疾病防控提供参考。【方法】从病死青年鸡脏器分离到病原菌TSA-1,通过革兰氏染色、生化试验和16S rRNA基因序列鉴定,并进行药敏试验、毒力基因检测、细胞毒性和黏附性试验、大蜡螟攻毒试验研究。【结果】分离株TSA-1在镜下呈短杆状、球状的革兰氏阴性菌,生化特性与奇异变形杆菌相一致,16S rRNA基因序列比对显示与奇异变形杆菌相似度为100%;药敏试验结果显示分离株TSA-1对氨苄西林、四环素、卡那霉素、头孢唑林等14种药物耐药,对环丙沙星、恩诺沙星等7种药物敏感;分离株还具有较强的生物被膜形成能力,携带ireA、ucaA、pmfA、atfA、ptA、zapA、hpmA和flhC这8种毒力基因,并对巨噬细胞RAW264.7表现出细胞毒性,而且对Caco-2细胞具有很强的黏附作用;同时对大蜡螟幼虫表现出比禽致病性大肠杆菌(avian pathogenic Escherichia coliO78,APEC-O78)更强的致死作用。【结论】从病死鸡脏器分离得到的奇异变形杆菌TSA-1具有多重耐药性,并携带多种毒力基因,对细胞和大蜡螟幼虫表现出强毒性作用,说明该菌是引起病鸡死亡的主要致病菌之一,应引起重视。     

The activation and inactivation of the Dunaliella salina chloroplast coupling factor 1 (CF1) in vivo and in situ

Preillumination of intact cells of the eukaryotic, halotolerant, cell-wall-less green alga Dunaliella salina induces a dark ATPase activity the magnitude of which is about 3–5-fold higher than the ATPase activity observed in dark-adapted cells. The light-induced activity arises from the activation and stabilization in vivo of chloroplast coupling factor 1 (CF₁). This activity, 150–300 μmol ATP hydrolyzed/mg Chl per h, rapidly decays (with a half-time of about 6 min at room temperature) in intact cells but only slowly decays (with a half-time of about 45 min at room temperature) if the cells are lysed by osmotic shock immediately after illumination. The activated form of the ATPase in lysed cells is inhibited if the membranes are treated with ferri- but not ferrocyanide, suggesting that the stabilization of the activated form of CF₁ is due to the reduction of the enzyme in vivo in the light.     

Repair and plasmid R46 mediated mutation requires inducible functions in Proteus mirabilis

Summary In Proteus mirabilis nalidixic acid or a predose of UV induce Rec protein formation, a portion of post-UV replication repair and post-UV replication enhancement. These inducible functions are not significantly affected by the plasmid R46, which renders P. mirabilis efficiently UV-mutable. The R46-mediated UV induction of rif ^r mutations requires additional inducible functions, as existing after malidixic acid treatment in rec ⁺ strains. After a nalidixic acid pretreatment UV efficient induction of rif ^r mutations occurs without an otherwise obligatory period of post-UV incubation prior to plating on rifampicin agar. The inducible character of this qualification of plasmid R46-mediated UV mutagenesis in P. mirabilis is evident from the inhibitory effects of chloramphenicol and starvation. Constitutive high-level synthesis of Rec protein in cells harboring the recombinant (multi-copy) rec ⁺ plasmid pPM1 reduced plasmid R46-mediated UV mutagenesis, probably by preventing (inducible?) functions required by the plasmid R46 repair-mutator.     

Recruitment of Type I Collagen Producing Cells from the Microvasculaturein Vitro

We have previously suggested that microvascular pericytes can differentiate into fibroblast-like, type I collagen-producing cells during excessive dermal scarringin vivo(Sundberg, C., Ivarsson, M., Gerdin, B., and Rubin, K.,Lab. Invest.74, 454–468, 1996). Here we have investigated to what extent pericytes derived from microvessels of full-term human placenta exhibited this capacityin vitro.Vascular fragments of human term placenta were isolated by enzymatic digestion and separation in Percoll. Their microvascular origin was ascertained by confocal microscopy using antibodies specific for endothelial cells (PAL-E) and pericytes (high-molecular-weight–melanoma-associated antigen). When vascular fragments were culturedin vitro,large cells with irregular edges migrated out from the fragments. After 4–6 days in culture, these cells started to proliferate and reached near confluence after approximately 8 days. The cultures were not overgrown by clones of cells with a high proliferative capacity, as demonstrated by cell membrane fluorescence staining and Ki67 expression. Expression of PAL-E, high-molecular-weight–melanoma-associated antigen, smooth muscle α-actin, desmin, and collagen synthesis (prolyl-4-hydroxylase and type I procollagen, as well as collagen pro-α1(I) mRNA) were followed during a culture period of 8 days. The cells were PAL-E negative but expressed high-molecular-weight–melanoma-associated antigen, smooth muscle α-actin, and desmin. Based on morphology and expression of the various markers, the outgrowing cells were identified as pericytes. With time in culture the cells decreased their expression of all these markers and increased their expression of prolyl-4-hydroxylase, type I procollagen, and collagen pro-α1(I) mRNA. Metabolic labeling and SDS–PAGE analysis of labeled proteins revealed that type I collagen was the major collagen species synthesized in the cultures. Our results support the hypotheses that pericytes can leave the vasculature and differentiate into collagen-producing cells and that cultured “fibroblasts” are derived from pericytes.     

Artificial shiro formation of Tricholoma matsutake

One type of soil collected from Maoer-shan in Heilongjiang Province, China was selected to induce hyphal growth of Tricholoma matsutake by a soil screening experiment. It was confirmed that hyphal growth of all the tested T. matsutake isolates was significantly stimulated in soil by supplemented with 0.5%∼2.0% olive oil. The aggregation of hyphae and soil resembled natural Shiro. The biomass of hyphae in the soil increases with increasing olive oil concentrations. Moreover, seedlings of Pinus densiflora grew well in the soil containing 0.5%∼1.0% olive oil and were also successfully infected by T. matsutake isolate A in the soil containing 1.0% olive oil. This study established a culture system of artificial Shiro formation and also provided a premise for formulation of culture substratum for fruit body formation of T. matsutake. __________ Translated from Mycosystema 2005, 24(2): 267–276 [译自: 菌物学报, 2005, 24(2): 267–276]     

Swarming Characteristics of Proteus mirabilis Under Anaerobic and Aerobic Conditions

Nutrients have a pronounced effect on the growth and swarming behaviour of Proteus mirabilis 7002. Iron, zinc, amino acids, and dioxygen are important for rapid growth and normal swarming. Anaerobically grown cultures of P. mirabilis 7002 were unable to swarm on anaerobically maintained rich nutrient agar. Upon exposure to aerobic conditions, P. mirabilis 7002 resumed swarming behaviour. Scanning electron microscopy was used to demonstrate the presence of community organization and mature rafts during normal swarming. These results support the importance of dioxygen and redox status in cell differentiation.