益生菌辅助治疗牙周病的研究进展

牙周病是累及牙周支持组织的慢性感染性疾病。牙菌斑生物膜中的微生物及其代谢产物是其必不可少的始动因素,可导致口腔微生态失衡和宿主免疫反应,最终引起牙周病的发生发展。目前,牙周病的基础治疗主要是机械清除牙菌斑生物膜和牙石,但治疗效果具有局限性。益生菌通过产生抑菌物质、刺激局部免疫反应、与致病菌争夺黏膜受体和营养物质,从而改善口腔微生态平衡,促进牙周病的治疗。本文就近年来益生菌在牙周病治疗上的实验和临床研究、作用机制、安全性等进行综述,为将来益生菌辅助治疗牙周病的应用提供参考。     

牙菌斑链球菌与牙龈卟啉单胞菌相互作用的研究

牙菌斑生物膜是牙周病最主要的致病因素。早期定植菌链球菌与晚期定植菌牙龈卟啉单胞菌(P.gingivalis)的相互作用复杂多样,而牙龈卟啉单胞菌是重要的牙周致病菌,本文就链球菌与牙龈卟啉单胞菌的相互作用作一综述。     

血链球菌与口腔微生态的关系

血链球菌与口腔微生态的关系大连医科大学微生态学研究所大连１１６０２７宋晓波口腔中的许多微生定居物与宿主之间保持着一种和谐共生关系——即临床健康状态。由于这些微生定居物以充足的数量占据着口腔各个生态位,它们对潜在的致病菌起着有效的防御功能〔１〕。血链球...     

变形链球菌对不同牙科充填材料的粘附及早期生物膜的形成

目的探讨变形链球菌对不同牙科充填材料的粘附和早期生物膜的形成.方法比较经放射性同位素3H-TDR(3H-胸腺嘧啶核苷)标记的变形链球菌对3种唾液包被的充填材料的粘附.采用蛋白质测量试剂盒定量分析其对唾液蛋白的吸附量;采用凝胶电泳和图像分析系统定量分析其对唾液白蛋白和α-淀粉酶的吸收率.结果各种材料对变形链球菌的粘附能力,对唾液蛋白的吸附能力均随着材料的不同而不同.Fuji IX对细菌的粘附量很高,但是对蛋白的吸附量却很低;而F2000对细菌的粘附量很低,对蛋白的吸附量却很高.结论在不同充填材料表面形成的生物膜是不同的,提示早期生物膜的形成具有一定的特异性.这种生物膜的差异对口腔微生态环境及龋病和/或牙周病的发展具有重要意义.     

PCR直接检测龈下菌斑主要可疑牙周致病菌

目的：应用PCR方法直接检测龈下菌斑主要可疑牙周致病菌与牙周病活动部位的关系,探讨其方法的可行性并探讨其主要可疑牙周致病菌的分布规律。方法：应用聚合酶链反应(polymerase chain reaction,PCR)直接检测龈下菌斑主要可疑致病菌16s RNA保守区域片段。40名受试者包括牙周病患者20人,每人同口取一个牙周病活动部位,一个相对健康或牙周病静止对照部位;成人健康者20人,每人各取一个标本。结果：龈下菌斑5种可疑牙周致病菌在牙周病活动部位的检出率牙龈卟啉菌为86％,福赛类杆菌为95％,螺旋体为86％,中间普氏菌和黑色普氏菌分别为95％和33％,均显著高于同口部位对照组和健康对照组。结论：PCR直接检测菌斑牙龈卟啉单胞菌、中间普氏菌、福赛类杆菌、齿密螺旋体及黑色普氏菌匀与牙周炎活动部位相关。     

牙周致病菌与阿尔茨海默病相关性研究进展

阿尔茨海默病(Alzheimer′s disease, AD)是一种进行性神经退行性疾病,其主要致病机制目前尚不清楚,临床上也缺乏有效的药物缓解病程的发生和发展。牙周病(periodontal disease, PD)是口腔常见病和多发病,牙周致病菌是其主要始动因子,越来越多的研究表明牙周致病菌与AD密切相关。本文主要围绕牙周致病菌与AD的相关性机制进行归纳总结,建议AD患者应重视口腔健康,PD的防治选择对AD具有重要作用,也为找寻AD治疗新靶点提供理论帮助。     

辽代契丹族女尸的口腔情况

本文描述一具契丹族女尸的口腔情况,着重介绍了该尸的龋齿、牙周病和牙齿磨耗。对其偏侧咀嚼所引起的下颌骨不对称等问题,进行了探讨。     

伴放线聚集菌与血链球菌、变异链球菌生态关系研究进展

人类口腔中定植的细菌有700余种,它们之间的相互关系与口腔疾病的发生、发展存在着密切的生态学联系。牙周病和龋病是人类常见的由口腔常驻细菌引起的细菌感染性疾病。牙周病是宿主的龈下正常微生物动态平衡被破坏,导致牙周袋的发生和牙槽骨的破坏等。     

星座链球菌引发脑脓肿1例

本文报道1例星座链球菌感染引发脑脓肿的病例。患者,男,54岁,视物成双19天,根据磁共振成像检查结果,不排除结核感染形成的结核球,予以抗结核治疗。同时对脑脊液进行宏基因组测序,结果提示直肠弯曲菌、福赛斯坦纳菌为主要致病菌。追问病史,患者有牙周病,近期左侧上颌疼痛明显。查阅文献有直肠弯曲菌引起颅内脓肿的报道,遂停用抗结核治疗,改用莫西沙星抗菌治疗。患者头痛不适加重,再次复查磁共振成像,提示病灶逐步扩大,病情变化较快,急诊行小脑占位性病变清除术,术中明确为脑脓肿;脑脓肿组织培养提示为星座链球菌。根据药敏给予利奈唑胺抗感染治疗,经综合治疗,患者病情平稳出院。本病例提示,星座链球菌作为一种口腔颌面部的常见感染菌,有可能引发脑脓肿,应引起临床工作者的注意。     

中草药治疗牙周病

牙周病是严重危害口腔健康的常见病。临床上多是以机械洁治后辅以抗菌药治疗。当前辅助的治疗药物多以抗生素类药物为主,但此类药物不仅破坏菌群平衡,还会使致病菌产生耐药性。中草药生物活性广泛、安全性高,利用其抑菌、抗炎、增加免疫、促进组织修复等功能治疗牙周病日益引起人们关注。本文对中草药治疗牙周病展开综述,为中草药的合理用药提供理论基础。     

Chimaereicella alkaliphila gen. nov., sp. nov., a Gram-negative alkaliphilic bacterium isolated from a nonsaline alkaline groundwater

A Gram-negative bacterium designated AC-74(T) was isolated from a highly alkaline groundwater environment (pH 11.4). This organism formed rod-shaped cells, is strictly aerobic, catalase and oxidase positive, tolerates up to 3.0% NaCl, has an optimum growth temperature of 30 degrees C, but no growth occurs at 10 or 40 degrees C, and an optimum pH value of 8.0, but no growth occurs at pH 7.0 or 11.3. The predominant fatty acids are iso-15:0, iso-17:1 omega9c and 16:1 omega7c and or iso-15:2OH. The G+C content of DNA was 43.5mol%. The phylogenetic analyses of the sequences of the 16s RNA genes indicated that strain AC-74(T) belongs to the family "Flexibacteriaceae" and is phylogenetically equidistant ( approximately 94.5%) from the majority of the species of the genus Algoriphagus and from the genus Hongiella. Based on the phylogenetic analyses and distinct phenotypic characteristics, we are of the opinion that strain AC-74(T), represents a new species of the novel genus for which we propose the name Chimaereicella alkaliphila gen. nov., sp. nov.     

Methanosarcina lacustris sp. nov., a new psychrotolerant methanogenic archaeon from anoxic lake sediments

A new psychrotolerant methanogenic archaeon strain ZS was isolated from anoxic lake sediments (Switzerland). The cells of the organism were non-motile cocci, 1.5-3.5 microm in diameter. The cells aggregated and formed pseudoparenchyma. The cell wall was Gram-positive. The organism utilized methanol, mono-, di-, trimethylamine and H2/CO2 with methane production. The temperature range for growth was 1-35 degrees C with an optimum at 25 degrees C. The DNA G+C content of the organism was 43.4. mol%. Analysis of the 16S rRNA gene sequence showed that strain ZS was phylogenetically closely related to members of the genus Methanosarcina, but clearly differed from all described species of this genus (95.6-97.6% of sequence similarity). The level of DNA-DNA hybridization of strain ZS with Methanosarcina barkeri and Methanosarcina mazei was 15 and 31%, respectively. Based on the results of physiological and phylogenetic studies strain ZS can be assigned to a new species of the genus Methanasarcina. The name Methanosarcina lacustris sp. nov. is proposed. The type strain is ZS (= DSM 13486T, VKM B-2268).     

Methanol utilization by a novel thermophilic homoacetogenic bacterium,Moorella mulderi sp. nov., isolated from a bioreactor

A thermophilic, anaerobic, spore-forming bacterium (strain TMS) was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as the energy source. Cells were gram-positive straight rods, 0.4-0.6 microm x 2-8 microm, growing as single cells or in pairs. The temperature range for growth was 40-70 degrees C with an optimum at 65 degrees C. Growth was observed from pH 5.5 to 8.5, and the optimum pH was around 7. The salinity range for growth was 0-45 g NaCl l(-1 )with an optimum at 10 g l(-1). The isolate was able to grow on methanol, H(2)-CO(2 )(80/20%, v/v), formate, lactate, pyruvate, glucose, fructose, cellobiose and pectin. The bacterium reduced thiosulfate to sulfide. The G+C content of the DNA was 53 mol%. Comparison of 16S rRNA genes revealed that strain TMS is related to Moorella glycerini (96%, sequence similarity), Moorella thermoacetica (92%) and Moorella thermoautotrophica (92%). On the basis of physiological and phylogenetic differences, strain TMS is proposed as a new species within the genus Moorella, Moorella mulderi sp. nov. (=DSM 14980, =ATCC BAA-608).     

Desulfobacter psychrotolerans sp. nov., a new psychrotolerant sulfate-reducing bacterium and descriptions of its physiological response to temperature changes

A psychrotrolerant acetate-oxidizing sulfate-reducing bacterium (strain akvb(T)) was isolated from sediment from the northern part of The North Sea with annual temperature fluctuations between 8 and 14 degrees C. Of the various substrates tested, strain akvb(T) grew exclusively by the oxidation of acetate coupled to the reduction of sulfate. The cells were motile, thick rods with round ends and grew in dense aggregates. Strain akvb(T) grew at temperatures ranging from -3.6 to 26.3 degrees C. Optimal growth was observed at 20 degrees C. The highest cell specific sulfate reduction rate of 6.2 fmol cell(-1) d(-1) determined by the (35)SO(2-)(40) method was measured at 26 degrees C. The temperature range of short-term sulfate reduction rates exceeded the temperature range of growth by 5 degrees C. The Arrhenius relationship for the temperature dependence of growth and sulfate reduction was linear, with two distinct slopes below the optimum temperatures of both processes. The critical temperature was 6.4 degrees C. The highest growth yield (4.3-4.5 g dry weight mol(-1) acetate) was determined at temperatures between 5 and 15 degrees C. The cellular fatty acid composition was determined with cultures grown at 4 and 20 degrees C, respectively. The relative proportion of cellular unsaturated fatty acids (e.g. 16:1omega7c) was higher in cells grown at 4 degrees C than in cells grown at 20 degrees C. The physiological responses to temperature changes showed that strain akvb(T) was well adapted to the temperature regime of the environment from which it was isolated. Phylogenetic analysis showed that strain akvb(T) is closest related to Desulfobacter hydrogenophilus, with a 16S rRNA gene sequence similarity of 98.6%. DNA-DNA-hybridization showed a similarity of 32% between D. hydrogenophilus and strain akvb(T). Based on phenotypic and DNA-based characteristics we propose that strain akvb(T) is a member of a new species, Desulfobacter psychrotolerans sp. nov.     

Isolation of a methanogen from deep marine sediments that contain methane hydrates,and description of Methanoculleus submarinus sp. nov

We isolated a methanogen from deep in the sediments of the Nankai Trough off the eastern coast of Japan. At the sampling site, the water was 950 m deep and the sediment core was collected at 247 m below the sediment surface. The isolated methanogen was named Nankai-1. Cells of Nankai-1 were nonmotile and highly irregular coccoids (average diameter, 0.8 to 2 micro m) and grew with hydrogen or formate as a catabolic substrate. Cells required acetate as a carbon source. Yeast extract and peptones were not required but increased the growth rate. The cells were mesophilic, growing most rapidly at 45 degrees C (no growth at /=55 degrees C). Cells grew with a maximum specific growth rate of 2.43 day(-1) at 45 degrees C. Cells grew at pH values between 5.0 and 8.7 but did not grow at pH 4.7 or 9.0. Strain Nankai-1 grew in a wide range of salinities, from 0.1 to 1.5 M Na(+). The described phenotypic characteristics of this novel isolate were consistent with the in situ environment of the Nankai Trough. This is the first report of a methanogenic isolate from methane hydrate-bearing sediments. Phylogenetic analysis of its 16S rRNA gene sequence indicated that it is most closely related to Methanoculleus marisnigri (99.1% sequence similarity), but DNA hybridization experiments indicated a DNA sequence similarity of only 49%. Strain Nankai-1 was also found to be phenotypically similar to M. marisnigri, but two major phenotypic differences were found: strain Nankai-1 does not require peptones, and it grows fastest at a much higher temperature. We propose a new species, Methanoculleus submarinus, with strain Nankai-1 as the type strain.     

Acetobacterium tundrae sp. nov., a new psychrophilic acetogenic bacterium from tundra soil

A new psychrophilic, anaerobic, acetogenic bacterium from the tundra wetland soil of Polar Ural is described. The organism fermented H2/CO2, formate, methanol, and several sugars to acetate as the sole end-product. The temperature range for growth was 1-30 degrees C with an optimum at 20 degrees C. The bacterium showed no growth at 32 degrees C. Cells were gram-positive, oval-shaped, flagellated rods 0.7-1.l x 1.1-4.0 microm in size when grown at 1-20 degrees C. At 25-30 degrees C, the cell size increased up to 2-3 x 10-15 microm due to a defect in cell division. The DNA G+C content of the organism was 39.2 mol%. Based upon 16S rDNA analysis and DNA-DNA reassociation studies, the organism was classified in the genus Acetobacterium as a new species, for which the name Acetobacterium tundrae sp. nov. is proposed. The type strain is Z-4493 (=DSM 9173T).     

Isolation and characterization of a new type of aerobic,oxalic acid utilizing bacteria,and proposal of Oxalicibacterium flavum gen. nov., sp. nov

A mesophilic, aerobic oxalic acid utilizing yellow-pigmented bacterium has been isolated from litter of oxalate producing plants in the region of Izmir (Turkey). It is motile by means of 1-3 polar flagella. Optimal growth occurred between 25-30 degrees C at pH 6.9. The G+C content of DNA is 62-64 mol % (Tm). Based on its morphological and biochemical features the organism belongs to the genus Pseudomonas, but differs from all the previously described species. The taxonomic relationships among strains described as or previously tentatively assigned to the genus Pseudomonas were investigated using numerical classification, DNA base composition and DNA-DNA hybridization. 16S rDNA sequences were determined for the strain TA17. On the basis of 16S rDNA sequence comparisons, physiological and biochemical characteristics, it is proposed to classify TA17T in a new genus and species for which the name Oxalicibacterium flavum gen. nov., sp. nov. is proposed. The type strain is TA17T (= NEU98T, = LMG 21571T).     

Desulfobulbus mediterraneus sp. nov., a sulfate-reducing bacterium growing on mono- and disaccharides

A new sulfate-reducing bacterium, strain 86FS1, was isolated from a deep-sea sediment in the western Mediterranean Sea with sodium lactate as electron and carbon source. Cells were ovoid, gram-negative and motile. Strain 86FS1 contained b- and c-type cytochromes. The organism was able to utilize propionate, pyruvate, lactate, succinate, fumarate, malate, alanine, primary alcohols (C(2)-C(5)), and mono- and disaccharides (glucose, fructose, galactose, ribose, sucrose, cellobiose, lactose) as electron donors for the reduction of sulfate, sulfite or thiosulfate. The major products of carbon metabolism were acetate and CO(2), with exception of n-butanol and n-pentanol, which were oxidized only to the corresponding fatty acids. The growth yield with sulfate and glucose or lactate was 8.3 and 15 g dry mass, respectively, per mol sulfate. The temperature limits for growth were 10 degrees C and 30 degrees C with an optimum at 25 degrees C. Growth was observed at salinities ranging from 10 to 70 g NaCl l(-1). Sulfide concentrations above 4 mmol l(-1) inhibited growth. The fatty acid pattern of strain 86FS1 resembled that of Desulfobulbus propionicus with n-14:0, n-16:1omega7, n-16:1 omega5, n-17:1 omega6 and n-18:1 omega7 as dominant fatty acids. On the basis of its phylogenetic position and its phenotypic properties, strain 86FS1 affiliates with the genus Desulfobulbus and is described as a new species, Desulfobulbus mediterraneus sp. nov.     

Expression of a temperature-sensitive esterase in a novel chaperone-based Escherichia coli strain

A new principle for expression of heat-sensitive recombinant proteins in Escherichia coli at temperatures close to 4 degrees C was experimentally evaluated. This principle was based on simultaneous expression of the target protein with chaperones (Cpn60 and Cpn10) from a psychrophilic bacterium, Oleispira antarctica RB8(T), that allow E. coli to grow at high rates at 4 degrees C (maximum growth rate, 0.28 h(-1)). The expression of a temperature-sensitive esterase in this host at 4 to 10 degrees C yielded enzyme specific activity that was 180-fold higher than the activity purified from the non-chaperonin-producing E. coli strain grown at 37 degrees C (32,380 versus 190 micromol min(-1) g(-1)). We present evidence that the increased specific activity was not due to the low growth temperature per se but was due to the fact that low temperature was beneficial to folding, with or without chaperones. This is the first report of successful use of a chaperone-based E. coli strain to express heat-labile recombinant proteins at temperatures below the theoretical minimum growth temperature of a common E. coli strain (7.5 degrees C).     

Balneomonas flocculans gen. nov., sp. nov., a new cellulose-producing member of the alpha-2 subclass of Proteobacteria

A new bacterial strain capable of producing cellulose was isolated from a hot spring. The isolate was Gram-negative, aerobic, and rod-shaped. The optimum temperature for growth was 40-45 degrees C. Methanol, glucose and other common carbohydrates were not utilized as sole growth substrates. Thiosulfate was not oxidized. The G+C content of the DNA was determined to be 64.0 mol%. Comparative 16S rDNA analysis indicated that Bosea thiooxidans and some strains of the genus Methylobacterium were the nearest relatives. The isolate can be distinguished from these relatives by its defectiveness in methanol utilization and thiosulfate oxidation. On the basis of its phenotypic properties and phylogeny, it is proposed that the isolate be designated Balneomonas flocculans gen. nov., sp. nov. The type strain is TFBT (= JCM 11936T, = KCTC 12101T, = IAM 15034T, = ATCC BAA-817T).