一株卡他布朗汉姆菌的重新鉴定

目的对中国医学细菌保藏管理中心库藏的一株卡他布朗汉姆菌CMCC(B)29103株进行重新鉴定。方法用营养琼脂培养基培养CMCC(B)29103株,对其进行形态观察、生理生化特性、脂肪酸组分、分子生物学等多相鉴定,同时与模式株DSM25388T相对照;分析CMCC(B)29103株的特征属性、进化位置以及与Acinetobacter indicus模式株DSM25388T的同源性。结果形态学特性、生理生化以及脂肪酸组分构成均与DSM25388T株十分相似,仅存在个别差异;16 S rRNA基因序列比对显示,CMCC(B)29103株与Acinetobacter(不动杆菌属)相近,与模式株DSM25388T相似性最高,为99.85%。基于Acinetobacter属所有成员的16 S rRNA和rpo B基因的系统进化分析均显示CMCC(B)29103与DSM25388T稳定聚类成一个独立分支,且二者的DNA-DNA同源性为78.3%。结论CMCC(B)29103株属于Acinetobacter indicus种,与模式株DSM25388T为不同的菌株,可将其更名为Acinetobacter i ndicus。     

Catabolite regulation in a diauxic strain and a nondiauxic strain of Streptococcus bovis

Streptococcus bovis JB1 utilized glucose preferentially to lactose and grew diauxically, but S. bovis 581AXY2 grew nondiauxically and used glucose preferentially only when the glucose concentration was very high (greater than 5 mM). As little as 0.1 mM glucose completely inhibited the lactose transport of JB1. The lactose transport system of 581AXY2 was at least tenfold less sensitive to glucose, and 1 mM glucose caused only a 50% inhibition of lactose transport. Both strains had phosphotransferase systems (PTSs) for glucose and lactose. The glucose PTSs were constitutive, but little lactose PTS activity was detected unless lactose was the energy source for growth. JB1 had approximately threefold more glucose PTS activity than 581AXY2 (1600 versus 600 nmol glucose (mg protein)⁻¹(min)⁻¹. The glucose PTS of JB1 showed normal Michaelis Menten kinetics, and the affinity constant (K _s ) was 0.12 mM. The glucose PTS of 581AXY2 was atypical, and the plot of velocity versus velocity/substrate was biphasic. The low capacity system had a K_s of 0.20 mM, but the K_s of the high capacity system was greater than 6 mM. On the basis of these results, diauxic growth is dependent on the affinity of glucose enzyme II and the velocity of glucose transport. Received: 22 January 1996 / Accepted: 18 March 1996     

Gender-specific differences in cannibalism between a laboratory strain and a field strain of a predatory mite

Many phytoseiid species, including Phytoseiulus persimilis, are known to engage in cannibalism when food is scarce and when there is no possibility to disperse. In nature adult females of P. persimilis are known to disperse when prey is locally depleted. Males, in contrast, are expected to stay and wait for potential mates to mature. During this phase, males can obtain food by cannibalizing. Therefore, we hypothesize that male P. persimilis exhibit a higher tendency to cannibalize than females. Because rearing conditions in the laboratory usually prevent dispersal, prolonged culturing may also affect cannibalistic behavior. We hypothesize that this should especially affect cannibalism by females, because they consume far more food. We tested these hypotheses by comparing males and females from two strains, one of which had been in culture for over 20 years, whereas the other was recently collected from the field. It is known that this predator can discriminate between kin and non-kin and prefers cannibalizing the latter, hence to construct lines with high relatedness we created isofemale lines of these two original strains. We subsequently tested to what extent the adult females and males of the original strains and the isofemale lines cannibalized conspecific larvae from the same strain/line in a closed system. Relatedness with the victims did not affect cannibalistic behavior, but males engaged more often in cannibalism than females, and females of the laboratory strain engaged more in cannibalism than those of the field strain, both in agreement with our ideas. We hypothesize that the difference in cannibalism between the two genders will increase when they have the alternative to disperse.     

Variations in erythropoiesis throughout a lifetime. Studies in a high-leukaemic mouse strain, the AKR/O strain, and a non-leukaemic strain, the WLO strain

We have studied the development of some haematological variables: erythropoiesis stimulating factor(s) (ESF), investigated with an in vitro cell culture assay; and the content of bone marrow and spleen erythroid colony forming unit(s) (CFU-E) and erythroid burst forming unit(s) (BFU-E) throughout the lifetime of 2 different mouse strains: the high-leukaemic, retrovirus infected AKR/O strain, and the non-leukaemic WLO strain. During the recovery phase of the postnatal anaemia, a peak in plasma ESF occurs in both strains. In young adult mice of both strains another peak in plasma ESF occurs at 70-110 days of age, associated with an increased number of bone marrow CFU-E, in a period when packed cell volume (PCV) remains stable. As the animals grow older PCV decreases, whereas plasma ESF and bone marrow CFU-E concentration increase. These results, together with in vitro dose-response studies, suggest reduced sensitivity to erythropoietin (Epo) of the ageing erythron. Throughout, the AKR/O strain has higher levels of plasma ESF and bone marrow CFU-E concentrations than the WLO strain, indicating both a reduced Epo responsiveness and some degree of ineffective erythropoiesis in the AKR/O strain. At all ages the AKR/O strain has a high concentration of Epo independent bone marrow CFU-E, possibly caused by the virus infection of precursor cells.     

尿道致病性大肠杆菌HEC4株和禽源致病性大肠杆菌E058株毒力相关特性的比较

对人尿道致病性大肠杆菌(uropathogenic Escherichia coli,UPEC)HEC4株和禽致病性大肠杆菌(avian pathogen-ic Escherichia coli,APEC)E058株进行毒力基因和其他相关特性的比较,结果显示,它们具有一些共同的毒力基因,包括一些存在于APEC中一个大的可传递质粒上的基因;同时,它们也具有一些相似的生化特性。对SPF鸡的致病性试验显示,这两株分离株具有相似的致病力。因此,对于APEC和UPEC的相关性,以及APEC是否有可能导致人尿道感染或者成为UPEC的毒力基因贮主,有待进一步研究。     

Global comparison of the membrane subproteomes between a multidrug-resistant Acinetobacter baumannii strain and a reference strain

Acinetobacter baumannii causes severe infections in compromised patients. We combined SDS-PAGE, two-dimensional gel electrophoresis and mass spectrometry (LC-MS/MS and MALDI-TOF) to separate and characterize the proteins of the cell envelope of this bacterium. In total, 135 proteins (inner and outer membrane proteins) were identified. In this analysis, we described the expression by this bacterium of RND-type efflux systems and some potential virulence factors. We then compared the membrane subproteome of a clinical multidrug-resistant (MDR) isolate with that of a reference strain. We found that the MDR strain expressed lower levels of the penicillin-binding-protein 1b, produced a CarO protein having different primary and quaternary structures to that of the reference strain, and expressed OmpW isoforms. We also showed that the clinical strain has a high ability to form biofilms consistent with the accumulation of some outer membrane proteins (OMPs) such as NlpE or CsuD that have already been described as involved in bacterial adhesion. These features may partly explain the MDR emergence of the clinical isolate.     

一株降解煤油菌株的筛选与鉴定

本文通过从污水处理厂活性污泥中分离得到一株高效降解轻油(煤油)细菌5092-2,通过形态学、16S rRNA鉴定该菌为Mangroveibacter sp.。进一步对其生长条件进行了研究,发现该菌在23℃到38℃、pH为5.0到9.0范围内生长无明显差异。在温度为35℃,pH 7.2~7.4,160 r/min培养7 d,菌株降解煤油的能力达到52.3%,具有进一步研究的价值。     

一株柴油脱硫菌的分离与鉴定

由最终产物为邻苯基苯酚（2-HBP）的二苯并噻吩（DBT）的4-S代谢途径出发,从被高硫原油污染的土样中分离,纯化得到一株能高效降解DBT的菌株,通过形态学,生理生化试验及16SrDNA基因测序,归类为Mycobacteriumsp．对细菌的培养条件进行研究,初步确定较为适宜的培养条件：温度为40℃,pH值为7．0,转速为200r／min．在此培养条件下,利用该菌株处理含有5mmol／LDBT的正十二烷模拟相,24h以后,DBT减少到3．36mmol／L,平均比脱硫率为8．34mmol DBTh^-1kg^-1 DCW（干细胞重）。     

产壳聚糖酶菌株的分离筛选及其诱变育种

利用以壳聚糖为唯一碳源的选择性培养基,从自然界中筛选得到一株壳聚糖酶活较高的菌株 ,其壳聚糖酶活为0.59U/mL.经初步鉴定,该菌株为芽孢杆菌属,以A表示.以该芽孢杆菌为出发菌株,经硫酸二乙酯(DES)诱变处理50 min后,筛选得到壳聚糖酶活明显提高的突变株DES-4,其壳聚糖酶活为1.60U/mL,是出发菌株的2.7倍.该突变株经连续传代5次后仍稳定产酶.研究表明,突变株DES-4的壳聚糖酶产生与芽孢形成之间关系密切,当芽孢充分形成后发酵液的壳聚糖酶活力不再增大.     

Degradation of o-methoxybenzoate by a two-member consortium made up of a gram-positive Arthrobacter strain and a gram-negative Pantotea strain

Aromatic carboxylic acids substituted with methoxylated groupsare among the most abundant products in alpechin, the wastes resulting from pressing olives to obtain olive oil. Degradation of o-methoxybenzoate by an stable consortium made of a grampositive bacterium, Arthrobacter oxydans, and gram negative one,Pantotea agglomerans, was shown to mineralize this compound efficiently. he concerted action of both microorganisms was needed for the two first steps n the process, namely, the conversion of o-methoxybenzoate into salycilate,and the hydroxylation of the latter to gentisate. Gentisate was further degraded by the Arthrobacter strain.     

草菇耐低温突变菌株Vtlt-1和原始菌株V23转录组差异的研究

为了培育草菇耐低温菌株与解析其耐低温的分子机制,采用紫外诱变的方法,选育出耐低温草菇菌株Vtlt-1,并利用表达谱芯片技术,比较突变菌株Vtlt-1与原始菌株V23的表达差异基因,筛选差异显著基因后利用GO（gene ontology）功能注释和KEGG（kyoto encyclopedia of genes and genomes）通路富集等方法分析,结果发现与V23相比Vtlt-1表达显著差异基因共有1 600个,其中704个基因上调表达,896个基因下调表达。针对差异基因的GO功能分类结果发现：生物学过程方面,差异基因主要分布在金属离子结合、氧化还原过程、碳水化合物的代谢与核酸的结合。细胞组分方面主要与细胞核相关;分子功能中,氧化还原活性以及解旋酶活性,依赖于ATP 的解旋酶活性、DNA指导的RNA聚合酶活性。KEGG注释结果发现差异表达基因主要富集在氨基酸与氮类物质的代谢、脂肪酸与生物碱的合成这两方面,此外还富集到核糖体的生物合成、细胞色素P450、RNA聚合酶、硫和氨基酸的代谢、核酸的修复等通路。这些结果为解析草菇耐低温机制提供分子依据和理论基础。     

Laccase production by a monokaryotic strain of Pycnoporus cinnabarinus derived from a dikaryotic strain

Monokaryotic Pycnoporus cinnabarinus strains were obtained from the dikaryotic strain I-938. One of these, designated MK18, consistently produced high laccase activity. In cultures of MK18 and I-938 where ferulic acid was added as laccase inducer, laccase activity was enhanced about 2.5-fold reaching 3400 U/l for the MK18 strain. Laccase was purified to homogeneity and under the selected growth conditions, only one isoform of the enzyme was produced. The N-terminal sequence was similar to the amino terminal sequence of laccase II from Trametes versicolor. The enzyme was stable at 60 C for more than 1 h.     

一株携带质粒的人两歧双歧杆菌的分离与鉴定

目的:分离携带天然质粒的人双歧杆菌.方法:用自制的改良型Blb双歧杆菌选择培养基,从人新鲜粪便分离双歧杆菌,对初步质粒检测阳性的单菌落通过糖发酵试验、(G C)mol%测定和16S rDNA序列分析,进行菌株鉴定.结果:筛选到一株携带天然质粒的人双歧杆菌,编号B200304,在1.0%琼脂糖凝胶上,测得质粒的相对分子质量约为22 kb.通过对该菌株的形态学观察和糖发酵试验等生理生化特征研究,证明该菌株为两歧双歧杆菌(Bifidobacterium bifidum);HPLC法测得其(G C)mol%为55.6,16SrDNA序列分析进一步证实该菌株为两歧双歧杆菌.结论:分离得到一株携带天然质粒的人两歧双歧杆菌新菌株.     

MRI-based strain and strain rate analysis of left ventricle: a modified hierarchical transformation model

Background

Different from other indicators of cardiac function, such as ejection fraction and transmitral early diastolic velocity, myocardial strain is promising to capture subtle alterations that result from early diseases of the myocardium. In order to extract the left ventricle (LV) myocardial strain and strain rate from cardiac cine-MRI, a modified hierarchical transformation model was proposed.

Methods

A hierarchical transformation model including the global and local LV deformations was employed to analyze the strain and strain rate of the left ventricle by cine-MRI image registration. The endocardial and epicardial contour information was introduced to enhance the registration accuracy by combining the original hierarchical algorithm with an Iterative Closest Points using Invariant Features algorithm. The hierarchical model was validated by a normal volunteer first and then applied to two clinical cases (i.e., the normal volunteer and a diabetic patient) to evaluate their respective function.

Results

Based on the two clinical cases, by comparing the displacement fields of two selected landmarks in the normal volunteer, the proposed method showed a better performance than the original or unmodified model. Meanwhile, the comparison of the radial strain between the volunteer and patient demonstrated their apparent functional difference.

Conclusions

The present method could be used to estimate the LV myocardial strain and strain rate during a cardiac cycle and thus to quantify the analysis of the LV motion function.

     

一株高效广谱染料降解细菌的分离鉴定及其脱色特性初探

从土壤样品中分离到一株高效染料脱色菌株N-4,根据形态学特征及16S rDNA基因序列分析,该菌株初步鉴定为Leucobacter sp.。利用表面响应法(RSM)对菌株N-4脱色活性深蓝K-R的主要因素进行优化,实验结果表明,菌株N-4脱色K-R的最优条件为:湿菌量10 g/L,染料浓度222 mg/L,硫酸铵1.5 g/L,果糖3.5 g/L,最佳脱色率为100%。此外,实验证明其对多种染料均具有较高的脱色效率。同时,考察了金属离子对染料脱色效率的影响,其中K+、Ca2+、Mg2+、Ba2+、Mn2+等对脱色具有促进作用,而Ni2+、Cu2+、Hg2+对脱色具有明显的抑制作用。     

Selection and adaptation of a phenol-degrading strain ofPseudomonas

Summary Phenol-degrading strain QT 31 ofPseudomonas sp. was selected among other phenol-resistant bacteria from activated sludges of wastewater treatment plant of an oil refinery. Its capacity of degradation was studied at different periods of adaptation, reaching a phenol biodegradation rate of 28 mg/l phenol per hour, from minimal, medium with 1000 mg/l phenol, after adaptation for 20 days.