Plasmid Transduction Using Bacteriophage Φadh for Expression of CC Chemokines by Lactobacillus gasseri ADH

Vaginal mucosal microfloras are typically dominated by Gram-positive Lactobacillus species, and colonization of vaginal mucosa by exogenous microbicide-secreting Lactobacillus strains has been proposed as a means of enhancing this natural mucosal barrier against human immunodeficiency virus (HIV) infection. We asked whether an alternative strategy could be utilized whereby anti-HIV molecules are expressed within the cervicovaginal milieu by endogenous vaginal Lactobacillus populations which have been engineered in situ via transduction. In this study, we therefore investigated the feasibility of utilizing transduction for the expression of two HIV coreceptor antagonists, the CC chemokines CCL5 and CCL3, in a predominant vaginal Lactobacillus species, Lactobacillus gasseri. Modifying a previously established transduction model, which utilizes L. gasseri ADH and its prophage Φadh, we show that mitomycin C induction of L. gasseri ADH transformants containing pGK12-based plasmids with CCL5 and CCL3 expression and secretion cassettes (under the control of promoters P6 and P59, respectively) and a 232-bp Φadh cos site fragment results in the production of transducing particles which contain 8 to 9 copies of concatemeric plasmid DNA. High-frequency transduction for these particles (almost 6 orders of magnitude greater than that for pGK12 alone) was observed, and transductants were found to contain recircularized expression plasmids upon subsequent culture. Importantly, transductants produced CC chemokines at levels comparable to those produced by electroporation-derived transformants. Our findings therefore lend support to the potential use of transduction in vaginal Lactobacillus species as a novel strategy for the prevention of HIV infection across mucosal membranes.In sub-Saharan Africa, HIV infections are acquired predominantly via heterosexual contact and women are at greatest risk of being infected, accounting for 60% of HIV infections (27). Currently, there is no effective vaccine against HIV, and therefore, the development of topical microbicides for the prevention of viral entry at the cervicovaginal and rectal mucosal surfaces could serve as a potentially important alternative means of preventing HIV infection via vaginal and possibly rectal intercourse. To eliminate the requirement for precoital application of microbicides, an alternative live-microbicide strategy whereby nonpathogenic bacteria capable of colonizing the genital or gut mucosa are engineered to secrete HIV inhibitors has been investigated (13, 3, 20). Vaginal mucosal microfloras are typically dominated by Gram-positive Lactobacillus species, usually L. crispatus, L. jensenii, L. gasseri, and L. iners, which serve as an important natural barrier to HIV infection (1, 29, 17, 8). The colonization of the vaginal mucosa by engineered microbicide-secreting Lactobacillus strains would therefore potentially provide an economical and long-lasting method of enhancing this natural mucosal barrier. However, the persistence of such engineered strains within the vaginal mucosal milieu may require that these strains exhibit a selective advantage over endogenous bacterial populations, which could lead to potentially undesirable perturbations of the host''s existing microflora.We asked whether an alternative and potentially less disruptive strategy than the introduction of exogenous strains into the cervicovaginal mucosa could be utilized, whereby anti-HIV molecules are expressed within the cervicovaginal milieu by endogenous vaginal Lactobacillus populations which have been engineered in situ via bacteriophage-mediated transfer of plasmid DNA (transduction). Transduction is a well-established phenomenon for a variety of bacterial species and has been used as a convenient and often more reliable method of DNA transfer than conventional methods (e.g., electroporation) for Gram-positive bacteria such as Staphylococcus species (4). Thus, the introduction of transducing phage particles specific for resident Lactobacillus species into the cervicovaginal milieu, subsequent transduction, and the secretion of antiviral molecules would negate the need for the introduction of exogenous engineered bacteria, which would have to compete with resident microflora.Few studies to date, however, have investigated transduction in Lactobacillus (26, 23, 21), and to our knowledge, there has been no attempt as yet to utilize transduction as a means of transferring expression plasmids into Lactobacillus species for the expression and secretion of anti-HIV molecules. Therefore, in this study, we undertook a proof-of-concept investigation to determine the feasibility of using transduction for this purpose. We show that high-frequency transduction into L. gasseri ADH by transducing particles derived from the Φadh phage can be achieved, where transducing particles contain pGK12-based expression plasmids (in concatemeric form) and transduction results in the production of transformants that express and secrete the CC chemokines and HIV coreceptor antagonists CCL5 (RANTES) and CCL3 (30).     

CC趋化因子偶联受体信号途径

Thechemokinesareafamilyofproinflammatorycytokinesthatactthroughcellsurfacereceptorstoregulatenumerousroutinephysiologicalandpathophysiologicalprocesses,includinghematopoiesis,T cellactivation ,angiogenesis,inflammatorydiseasesaswellasHIV 1infection[1,2 ].Thesesmallpeptidesaretypicallycomposedof 70 - 1 30aminoacidsandarecharacterizedbythepresenceoftwodisulphidebondsformedbetweenfourconservedcysteineresidues.Chemokinesareclassifiedintofoursubfamiliesaccordingtothepatternofconservedcysteinesinth…     

CC趋化因子与心肌梗死的研究进展

CC类趋化因子亚家族是趋化因子家族中成员最多、研究最广泛的一大类细胞因子,其主要功能是参与炎症细胞激活、迁移、黏附等病理生理过程.大量研究表明,CC类趋化因子亚家族成员参与了心肌梗死后病理过程的各个阶段.其中研究最为深入的是单核细胞趋化蛋白1 (monocyte chemoattractant protein-1,MCP-1)及其受体CC趋化因子受体2 (CC chemokine receptor 2,CCR2). MCP-1和CCR2在心肌梗死后炎症期、增殖期及疤痕愈合期都发挥了重要作用从而影响梗死后心室重构.近年来,CC类趋化因子亚家族其他成员亦被逐渐揭示参与了心肌梗死的发展.本文结合以往大量文献,就CC类趋化因子亚家族在心肌梗死各个阶段中的作用,尤其是梗死后各期对于心室重构的影响进行综述,以期为今后的CC趋化因子研究提供方向,为相关疾病的预防和治疗研究提示潜在的药物靶点.     

TIP30/CC3基因研究进展

人的TIP30蛋白是能特异性地提高HIV-1增殖调节蛋白Tat的转录辅助因子,其序列与CC3蛋白是相同的,而CC3蛋白是与肿瘤转移抑制有关的。TIP30/CC3是短链脱氢酶/还原酶(SDR)家族的一个成员,也是一个丝氨酸/苏氨酸激酶。它的抑癌功能不断得到发现和证实,作用机理也被不断深入研究,为肿瘤治疗带来了新的希望。一些新的促凋亡途径的提出,加深了人们对这一方面的了解。但是,依然有许多问题需要解决,需要更深入的研究。本文就TIP30/CC3基因的发现、命名、结构特征、生理功能等方面问题进行了综述,并在文章最后对TIP30/CC3基因的研究进行了展望。     

CC趋化因子配体2与肝疾病

近年来CC趋化因子配体2(chemokine(C-C motif)ligand 2,CCL2)在肝脏疾病发病机制中的作用越来越受到重视.大量研究表明,CCL2在各种肝损伤中表达上调.CCL2是炎症反应的主要调节因子,通过与其受体CCR2相互作用,使血液中的单核细胞穿过血管内皮向炎症部位迁移.白色脂肪组织分泌的CCL2能直接诱导肝细胞的脂肪聚集,与非酒精性肝病的发病机理密切相关.肝实质细胞分泌的CCL2能激活并募集肝星形细胞,参与肝纤维化甚至肝硬化的形成.CCL2能介导肝癌细胞的转移和浸润,刺激肿瘤血管生成,其与肿瘤的关系也成为研究的热点.本文将阐述CCL2与病毒性肝炎、酒精性肝炎、非酒精性脂肪性肝炎、肝纤维化、肝硬化和肝癌的研究进展.     

Human-to-Bovine Jump of Staphylococcus aureus CC8 Is Associated with the Loss of a β-Hemolysin Converting Prophage and the Acquisition of a New Staphylococcal Cassette Chromosome

Staphylococcus aureus can colonize and infect both humans and animals, but isolates from both hosts tend to belong to different lineages. Our recent finding of bovine-adapted S. aureus showing close genetic relationship to the human S. aureus clonal complex 8 (CC8) allowed us to examine the genetic basis of host adaptation in this particular CC. Using total chromosome microarrays, we compared the genetic makeup of 14 CC8 isolates obtained from cows suffering subclinical mastitis, with nine CC8 isolates from colonized or infected human patients, and nine S. aureus isolates belonging to typical bovine CCs. CC8 isolates were found to segregate in a unique group, different from the typical bovine CCs. Within this CC8 group, human and bovine isolates further segregated into three subgroups, among which two contained a mix of human and bovine isolates, and one contained only bovine isolates. This distribution into specific clusters and subclusters reflected major differences in the S. aureus content of mobile genetic elements (MGEs). Indeed, while the mixed human-bovine clusters carried commonly human-associated β-hemolysin converting prophages, the bovine-only isolates were devoid of such prophages but harbored an additional new non-mec staphylococcal cassette chromosome (SCC) unique to bovine CC8 isolates. This composite cassette carried a gene coding for a new LPXTG-surface protein sharing homologies with a protein found in the environmental bacterium Geobacillus thermoglucosidans. Thus, in contrast to human CC8 isolates, the bovine-only CC8 group was associated with the combined loss of β-hemolysin converting prophages and gain of a new SCC probably acquired in the animal environment. Remaining questions are whether the new LPXTG-protein plays a role in bovine colonization or infection, and whether the new SCC could further acquire antibiotic-resistance genes and carry them back to human.     

Rate of activation and deactivation of K∶Cl cotransport by changes in cell volume in hemoglobin SS,CC and AA red cells

Red blood cells (RBC) of subjects homozygous for hemoglobin A (AA), C (CC) and S (SS) exhibit different cell volumes which might be related to differences in cell volume regulation. We have investigated how rapidly K:Cl cotransport is activated and deactivated to regulate the cell volume in these cells. We measured the time course of net K⁺ efflux after step changes in cell volume and determined two delay times: one for activation by cell swelling and a second for deactivation by cell shrinkage. Cell swelling induced by 220 mOsm media activated K⁺ efflux to high values (10–20 mmol/ liter cell x hr) in CC and SS; normal AA had a threefold lower activity. The delay time for activation was very short in blood with a high percentage of reticulocytes (retics): (SS, 10% retics, 1.7±0.3 min delay, n=8; AA, 10% retics, 4±1.5 min, n=3; CC, 11.6% retics, 4±0.3, n=3) and long in cells with a smaller percentage of reticulocytes: (AA, 1.5% retics, 10±1.4 min, n=8; CC whole blood 6% retics, 10±2.0 min, n=10, P<0.02 vs. SS). The delay times for deactivation by cell shrinking were very short in SS (3.6±0.4 min, n=8, P<0.02) and AA cells with high retics (2.7±1 min, n=3) and normal retics (2.8±1 min, n=3), but 8–15-fold longer in CC cells (29±2.8 min, n=9).Density fractionation of CC cells (n=3) resulted in coenrichment of the top fraction in reticulocytes and in swelling-activated cotransport (fourfold) with short delay time for activation (4±0.3 min) and long delay for deactivation (14±4 min). The delay time for activation, but not for deactivation, increased markedly with increasing cell density. These findings indicate that all CC cells do not promptly shut off cotransport with cell shrinkage and high rates of cellular K⁺ loss persist after return to isotonic conditions.In summary, (i) K:Cl cotransport is not only very active in young cells but it is also very rapidly activated and deactivated in young AA and SS cells by changes in cell volume. (ii) Delay times for cotransport activation markedly increased with RBC age and in mature cells with low cotransport rates, long delay times for activation were observed. (iii) The long delay time for deactivation exhibited even by young CC cells induces a persistent loss of K⁺ after cell shrinkage which may contribute in vivo to the uniformly low cell volume, low K⁺ and water content of CC cells.This research was supported by National Institutes of Health grants Shannon Award HL-35664, HL-42120, Sickle Cell Center grant HL-38655, and a Grant-in-Aid of the New York Branch of the American Heart Association. The technical help of Sandra M. Suzuka, M.S. is gratefully acknowledged.     

Analysis of the CC chemokine receptor 5 (CCR5) delta-32 polymorphism in inflammatory bowel disease

The inflammatory bowel diseases (IBD) Crohn's disease (CD) and ulcerative colitis (UC) are complex multifactorial traits involving both environmental and genetic factors. Recent studies have shown the important role of pro-inflammatory cytokines and chemokines, including RANTES, in IBD. RANTES is the natural ligand for the CC-chemokine receptor 5 (CCR5). The chromosomal location of the CCR5 gene on 3p21 coincides with an IBD-susceptibility locus identified by genome-wide scanning. A 32-bp deletion (A32) in the CCR5 gene results in a nonfunctional receptor and is found with high frequency in Caucasians. In this study, we investigated the presence of the CCR5delta32 allele in a large cohort of IBD patients and in a healthy control population. Blood samples were obtained from 538 unselected IBD cases (433 unrelated IBD patients: 289 CD, 142 UC, 2 indeterminate colitis; 105 affected first-degree relatives) and 135 unaffected first-degree family members. Of the IBD patients, 36% had familial IBD with at least two members being affected. There were no significant differences in the CCR5delta32 mutation frequency between IBD patients and healthy controls, nor between CD and UC patients. There was no correlation between the CCR5delta32 genotype and the age at IBD-diagnosis, the frequency of surgical intervention, or disease localization. Only the association between CCR5delta32 homozygosity and the presence of anal lesions in CD patients was statistically significant (P=0.007). Analysis by the transmission/disequilibrium test showed no significant transmission distortion to the probands or their clinically silent siblings. Based on these results, it is unlikely that the CCR5delta32 allele is an important marker for predisposition to IBD.     

CC类趋化因子亚家族与心肌梗死的研究进展

CC类趋化因子亚家族是趋化因子家族中成员最多、研究最广泛的一大类细胞因子,其主要功能参与炎症细胞激活、迁移、粘附等病理生理过程。大量研究表明,CC类趋化因子亚家族成员参与了心肌梗死后病理过程的各个阶段。其中研究最为深入的为单核细胞趋化蛋白-1（monocyte chemoattractant protein-1,MCP-1）及其受体CC趋化因子受体2（CC chemokine receptor 2,CCR2）,在心肌梗死后炎症期、增殖期及疤痕愈合期都发挥了重要作用从而影响梗死后心室重构。近年来,CC类趋化因子亚家族其他成员亦被逐渐揭示参与了心肌梗死的发展。本文结合以往大量文献将对CC类趋化因子亚家族在心肌梗死各个阶段中尤其是梗死后各期对于心室重构的影响进行综述,以期为今后的实验研究提供方向及疾病的预防和治疗提供药物靶点。     

白细胞介素2调节CC亚族趋化因子基因表达

白细胞介素２调节ＣＣ亚族趋化因子基因表达几项研究已表明,ＣＣ亚族趋化因子（ＣＣ－ＣＫ）可吸引Ｔ细胞,其中主要是ＣＤ４５ＲＯ＋、具有记忆表型的Ｔ细胞。为了进一步弄清ＣＣ－ＣＫ的趋化作用及ＣＣ－ＣＫ受体（ＣＣ－ＣＫＲ）的表达调节,Ｌｏｅｔｓｃｈｅｒ等将血...     

IFN-Alpha Receptor-1 Upregulation in PBMC from HCV Na?ve Patients Carrying CC Genotype. Possible Role of IFN-Lambda

Background and Aims

IL-28B gene polymorphisms predict better therapeutic response and spontaneous clearance of HCV. Moreover, higher expression of IFN-lambda has been reported in patients with the rs12979860 CC favourable genotype. The study aim was to establish possible relationships between IL-28B rs12979860 genotypes and expression of IFN-alpha receptor-1 (IFNAR-1) in naïve HCV patients, and to explore the possible role of IFN-lambda.

Methods

IFNAR-1 mRNA levels were measured in PBMC from naïve patients with chronic hepatitis C with different IL-28 genotypes. The ability of IFN-lambda to up-regulate the expression of IFNAR-1 was established in PBMC from healthy donors carrying different IL-28B genotypes.

Results

Lower IFNAR-1 mRNA levels were observed in PBMC from HCV-infected naïve patients as compared to healthy donors. In healthy donors, IFNAR-1 mRNA levels were independent from IL-28B genotype, while in HCV patients, an increasing gradient was observed in TT vs CT vs CC carriers. In the latter group, a direct correlation between IFNAR-1 and endogenous IL-28B expression was observed. Moreover, IFN-lambda up-regulated IFNAR-1 expression in normal PBMC in a time-and dose-dependent manner, with a more effective response in CC vs TT carriers.

Conclusion

Endogenous levels of IFN-lambda may be responsible for partial restoration of IFNAR-1 expression in HCV patients with favourable IL-28 genotype. This, in turn, may confer to CC carriers a response advantage to either endogenous or exogenous IFN-alpha, representing the biological basis for the observed association between CC genotype and favourable outcome of either natural infection (clearance vs chronicization) or IFN therapy.     

HIV共受体—CC类趋化因子受体—5

ＨＩＶ共受体——ＣＣ类趋化因子受体┐５黄仕和秦椿华（卫生部武汉生物制品研究所,武昌４３００６０）（美国得克萨斯Ａ＆Ｍ大学毒理学系）关键词ＨＩＶ共受体ＣＣ类趋化因子受体－５继冯愈等发现融合素是嗜Ｔ细胞ＨＩＶ－１的融合辅助因子后,邓洪魁及其同事发现了初始...     

Somatic cell hybridization of ’oxy’ CMS Brassica juncea (AABB) with B. oleracea (CC) for correction of chlorosis and transfer of novel organelle combinations to allotetraploid brassicas

Alloplasmic lines of cultivated Brassica species with B. oxyrrhina cytoplasm are male-sterile and suffer from severe chlorosis. We developed male-sterile lines corrected for chlorosis by fusing protoplasts of CMS B. juncea (AABB) with ’oxy’ cytoplasm and normal B. oleracea (CC). A large number of male-sterile AABBCC somatic hybrids with desirable organelle combinations, i.e. chloroplasts of B. oleracea and mitochondria with recombinant genomes, were recovered. While no recombination was observed in the chloroplast genome, the mitochondrial genome showed extensive recombination that resulted in the appearance of totally novel banding patterns in some of the hybrids. Hybrids with a parental-type mitochondrial genome as well as recombinant patterns close to either of the parental types were also obtained. Using AABBCC somatic hybrids as bridging material, we transferred the desirable organelle combinations to B. juncea (AABB), B. napus (AACC), and B. carinata (BBCC). Many of these lines are now at advanced stages of backcrossing and show stable inheritance of the CMS character and do not suffer from chlorosis. Received: 9 August 1999 / Accepted: 14 September 1999     

Nitric Oxide Exposure of CC531 Rat Colon Carcinoma Cells Induces γ-glutamyltransferase which May Counteract Glutathione Depletion and Cell Death

&#110 -Glutamyltransferase (GGT) has a central role in glutathione homeostasis by initiating the breakdown of extracellular GSH. We investigated in the present study whether nitric oxide exposure of CC531 rat colon carcinoma cells modulates GGT and how the activity of the enzyme affects the level of intracellular GSH. The data show that GGT activity was induced in a dose-related manner by two NO-donors (spermineNONOate and nitrosoglutathione) and that antioxidants partly inhibited the induction. SpermineNONOate lowered intracellular GSH and induced apoptosis. Cultivating the cells in cystine-depleted medium also resulted in a 50% lowering of GSH, but this was avoided when GSH was added to the medium. This effect was mediated by the activity of GGT and shown after inhibiting GGT activity with acivicin and cyst(e)ine transporters with alanine and homocysteic acid. This shows that the cells benefit from GGT in maintaining the intracellular GSH level. Cells with induced GGT activity obtained after NO incubation showed a higher uptake rate of cysteine (2-fold), measured by incubating the cells with 35 S-radiolabeled GSH. The enzyme was also induced by interferon- &#110 and tumor necrosis factor- &#102, but this induction was not connected to activation of the endogenous nitric oxide synthase, as the addition of aminoguanidine, a NO-synthase inhibitor, did not affect the induction. The present study shows that the activity of GGT is upregulated by NO-donors and that the colon carcinoma cells, when cultivated in cystine-depleted medium, benefit from the enzyme in maintaining the intracellular level of GSH. Thus, the enzyme will add to the protective measures of the tumor cells during nitrosative stress.     

An application of the SCF,MBPT and CC correlated densities: a graphical display along the potential energy surface of CH4 → CH3 + H

The potential energy surface for the dissociation of methane CH₄ → CH₃ + H is investigated by displaying the gradients of the SCF and correlated electron density as colored regions on isodensity surfaces. It is shown that coloring the gradients of the electron density is sensitive enough to show differences among the SCF, MBPT (2), D-MBPT(4) and L-CCD densities.     

东太平洋CC南区有孔虫埋藏群特征及意义

通过对研究区４１个站位的表层沉积物样、１０个自返重力管（短柱）样和３个大型重力活塞样的研究,共鉴定有孔虫４８属８７种,其中浮游类６属１４种,钙质底栖类３２属６３种,胶结壳类９属１０种。表层沉积物中钙质有孔虫的分布表明,本区的ＣＣＤ界线大致为４９００ｍ。从柱状样有孔虫面貌看,其时代主要为早－中中新世,并可分为３个组合。大部分地区缺失中中新统－第四系。