五株乳酸菌和三株芽孢杆菌的生物学特性和功能

【背景】乳酸菌和芽孢杆菌是应用于生产最多的益生菌,但不同菌株间的生长特性均不相同,因此了解菌株的生物学特性具有重要意义。【目的】研究菌株的生物学特性,能合理地开发和利用菌株,以保证菌株生产应用的安全性。【方法】活化后鉴定5株乳酸菌和3株芽孢杆菌并对其形态进行观察,探究菌株的生长曲线、产酸能力及最适生长条件,测定菌株的抑菌活性和产酶性能,同时探究菌株的益生性和安全性。【结果】五株乳酸菌分别编号鉴定为干酪乳杆菌R1、副干酪乳杆菌R2、香肠乳杆菌R3、福莱乳杆菌R4和唾液乳杆菌R5;3株芽孢杆菌分别编号命名为贝莱斯芽孢杆菌Y1、枯草芽孢杆菌Y2和地衣芽孢杆菌Y3。八株菌形态结构均不相同但都为杆状,均在2–10 h为对数生长期,18–24 h为稳定期,培养24 h时乳酸菌和芽孢杆菌的活菌数均保持在10⁹和10⁸ CFU/mL,最适生长温度为37.0℃。乳酸菌具有较强的产酸能力和抑菌活性,芽孢杆菌有较强的产酶性,在人工胃液中都有较强的耐受性。八株菌都无溶血活性、无毒力基因、对抗生素都保持中度敏感以上;其中唾液乳杆菌有四环素耐药基因,但对四环素抗性为中度敏感。【结论】八株菌生长繁殖速度快,乳酸菌产酸能力和抑菌活性较强,芽孢杆菌具有较强的产酶性能,在体外具有较好的益生性和安全性,可应用于生产实践。     

乳酸菌阴道胶囊辅助治疗 外阴阴道念珠菌病的中文文献Meta分析

摘要：目的 系统评价乳酸菌阴道胶囊辅助治疗外阴阴道念珠菌病（VVC）的疗效及安全性。方法 计算机联机检索Cochrane图书馆、CNKI、VIP、万方数据库（各数据库检索时间为创建至2014年12月）中关于乳酸菌阴道胶囊辅助治疗VVC的随机对照试验（RCT）,用RevMan 5.3软件对数据进行Meta分析。结果 共纳入18篇RCT,包括2 405例患者。Meta分析结果显示,乳酸菌阴道胶囊辅助治疗VVC效果优于对照组[RR=2.43,95%CI（1.98,2.98）,P<0.00001]。结论 基于现有临床证据,乳酸菌阴道胶囊辅助治疗VVC有效,安全性高。但由于纳入研究数量较少,研究质量不统一,本结论尚需要更多大样本、高质量临床RCT予以证实。     

乳酸菌阴道胶囊辅助治疗外阴阴道念珠菌病的中文文献Meta分析

目的系统评价乳酸菌阴道胶囊辅助治疗外阴阴道念珠菌病(VVC)的疗效及安全性。方法计算机联机检索CNKI、VIP、万方数据库(各数据库检索时间为创建至2014年12月)中关于乳酸菌阴道胶囊辅助治疗VVC的随机对照试验(RCT),用RevMan 5.3软件对数据进行Meta分析。结果共纳入18篇RCT,包括2 405例患者。Meta分析结果显示,乳酸菌阴道胶囊辅助治疗VVC效果优于对照组[OR=2.43,95%CI(1.98,2.98),P0.000 01]。结论基于现有临床证据,乳酸菌阴道胶囊辅助治疗VVC有效,安全性高。但由于纳入研究数量较少,研究质量不统一,本结论尚需要更多大样本、高质量临床RCT予以证实。     

乳酸菌阴道胶囊降低外阴阴道念珠菌病复发的中文文献Meta分析

目的系统评价乳酸菌阴道胶囊降低外阴阴道念珠菌病(VVC)复发的疗效及安全性。方法计算机联机检索Cochrane图书馆、CNKI、VIP、万方数据库(各数据库检索时间为创建至2014年12月)中关于乳酸菌阴道胶囊降低VVC复发的随机对照试验(RCT),用RevMan 5.3软件对数据进行Meta分析。结果共纳入18篇RCT,包括2 450例患者。Meta分析结果显示,乳酸菌阴道胶囊降低VVC复发的效果优于对照组[RR=0.34,95%CI(0.28,0.41),P0.000 01]。结论基于现有临床证据,乳酸菌阴道胶囊降低VVC复发有效,安全性高。但由于纳入研究数量较少,研究质量不统一,本结论尚需要更多大样本、高质量临床RCT予以证实。     

阴道用乳酸菌制剂辅助治疗RVVC的Meta分析

目的系统评价阴道用乳酸菌制剂辅助治疗复发性外阴阴道假丝酵母菌病(RVVC)的疗效及安全性。方法计算机检索CNKI、万方、维普、PubMed及Cochrane等数据库(检索时间为各数据库创建时间至2018年1月),纳入关于阴道用乳酸菌制剂辅助治疗RVVC的临床随机对照试验(RCT),采用RevMan 5.3软件对相关研究进行Meta分析。结果共纳入32篇RCT,包括3 635例患者,结果显示:阴道用乳酸菌制剂辅助治疗RVVC的痊愈率优于单纯抗菌药物[P0.001,OR=2.15,95%CI(1.81,2.54)],总有效率高[P0.001,OR=3.26,95%CI (2.5,4.26)],复发率低[P0.001,OR=0.19,95%CI (0.15,0.25)],不良反应发生率低,Begg′s检验表明纳入的RCT研究无发表偏倚(P=0.1020.05)。结论基于现有临床证据,阴道用乳酸菌制剂辅助治疗RVVC疗效优于单纯抗菌药物,可有效改善临床症状,减少疾病发作次数,安全性高,不良反应发生率低,值得临床推广使用。     

重组人干扰素α2b凝胶联合乳酸菌阴道胶囊对宫颈高危型HPV持续感染的治疗

目的观察重组人干扰素α2b凝胶联合乳酸菌阴道胶囊治疗宫颈高危型人乳头瘤病毒(highrisk human papillomavirus,HPV)持续感染的临床效果。方法将110例宫颈高危型HPV持续感染而液基细胞学检查阴性的患者随机分为两组,其中对照组(58例)予以重组人干扰素α2b凝胶治疗,观察组(52例)予以重组人干扰素α2b凝胶联合乳酸菌阴道胶囊治疗,两组患者均连续治疗3个月经周期。比较两组患者HPV转阴率及阴道微生态改善情况。结果观察组患者治疗总有效率(82.69%)高于对照组(63.79%),差异有统计学意义(χ²=4.937,P=0.026)。治疗后,两组患者阴道微生态失调率均有所下降,且观察组改善情况更为显著(均P<0.05)。治疗后观察组患者阴道菌群密集度及多样性显著低于治疗前,其微生物功能指标优于对照组,乳杆菌定植率高于对照组,病原菌检出率低于对照组(均P<0.05)。结论在重组人干扰素α2b凝胶治疗的基础上联合应用乳酸菌阴道胶囊能明显提高宫颈高危型HPV持续感染的转阴率,其中促进阴道微生态恢复平衡可能是其发挥作用的机制之一。     

Cd2+结合肽的筛选及与重金属离子的亲和作用*

利用噬菌体随机十二肽库和亲和层析技术对重金属Cd进行亲和筛选,共获得两条Cd结合肽序列。将展示有Cd²⁺结合肽的噬菌体单克隆扩增物对不同重金属离子(Cd²⁺、Cr²⁺、Cu²⁺、Co²⁺、Zn²⁺、Ni²⁺)螯合的树脂进行亲和测定,结果表明Cu²⁺、Co²⁺、Zn²⁺、Ni^2+<     

宫颈癌患者阴道微生态变化及其与细胞免疫的相关性探讨

目的探讨宫颈癌患者阴道微生态变化及其与细胞免疫的相关性。方法回顾性分析2018年1月-2020年5月本院收治的且经病理确诊的73例宫颈癌患者(宫颈癌组)和同期65例体检筛查宫颈正常者(正常宫颈组)的临床病例资料。两组均采用直接涂片法、革兰染色法检测阴道分泌物中乳酸杆菌、滴虫、支原体、衣原体、细菌性阴道病、霉菌、淋菌、假丝酵母菌、人乳头瘤病毒(HPV)及阴道唾液酸甘酶活性、白细胞酯酶、过氧化氢等。另采用流式细胞仪检测外周血T淋巴细胞(CD3⁺、CD4⁺、CD8⁺、CD4⁺/CD8⁺)及自然杀伤细胞(CD16⁺CD56⁺)水平。观察各组阴道微生态变化情况及外周血CD3⁺、CD4⁺、CD8⁺、CD4⁺/CD8⁺、CD16⁺CD56⁺水平。另对比宫颈癌组中感染致病微生物者、阴道微生态失调者与未感染致病微生物者、阴道微环境正常者的CD3⁺、CD4⁺、CD8⁺、CD4⁺/CD8⁺、CD16⁺CD56⁺水平,采用Pearson相关性分析法分析宫颈癌组阴道乳酸杆菌定植密度与细胞免疫的相关性。结果宫颈癌组滴虫、支原体、衣原体、霉菌、细菌性阴道病、HPV感染检出率及阴道微生态失调率均高于正常宫颈组,宫颈癌组乳酸杆菌定植密度低于正常宫颈组,差异均有统计学意义(P<0.05),宫颈癌组淋菌、假丝酵母菌感染检出率与正常宫颈组比较差异均无统计学意义(P>0.05)；宫颈癌组CD3⁺、CD4⁺、CD4⁺/CD8⁺、CD16⁺CD56⁺水平均低于正常宫颈组,CD8⁺水平高于正常宫颈组,差异均有统计学意义(P<0.05)；宫颈癌组中滴虫、支原体、衣原体、霉菌、细菌性阴道病、HPV感染者及阴道微生态失调者CD3⁺、CD4⁺、CD4⁺/CD8⁺、CD16⁺CD56⁺均低于未感染者、阴道微环境正常者,CD8⁺高于未感染者、阴道微环境正常者,差异均有统计学意义(P<0.05)；宫颈癌患者乳酸杆菌定植密度与CD3⁺、CD4⁺、CD4⁺/CD8⁺、CD16⁺CD56⁺呈正相关性(P<0.05),与CD8⁺呈负相关性(P<0.05)。结论宫颈癌患者阴道致病微生物感染率较健康人群高,同时细胞免疫功能降低,增加罹患宫颈癌的风险。     

金属离子对黄柄曲霉生长和抗真菌抗生素合成的影响*

不同的金属离子对兼性海洋霉菌黄柄曲霉 1 79的生长有不同的影响。在0.002mol/L的浓度下 ,Hg²⁺、Ag⁺和Cr³⁺能强烈抑制该菌的生长 ,Pb²⁺、Sr²⁺、Co²⁺、Al³⁺对其生长有一定的抑制 ,生长量低于对照 ;Mn²⁺、Ba²⁺、Zn²⁺对其生长没有明显影响 ;Cu相似文献   

苛求芽孢杆菌尿囊酸酰胺水解酶性质的研究

研究了苛求芽孢杆菌尿囊酸酰胺水解酶的基本性质、稳定性及调节。粗酶作用于尿囊酸的Ｋｍ为７．１ｍｍｏｌ／Ｌ,Ｖｍａｘ为５０μｍｏｌ／Ｌ·ｍｉｎ^－１·ｍｇ^－１蛋白质。Ｃｏ^２＋、Ｎｉ^２＋、Ｃｄ^２＋可部分代替Ｍｎ^２＋作为金属辅因子,活力分别为对照的１７％,１４％和１１％。Ｆｅ^２＋、Ｃｕ^２＋、Ｚｎ^２＋分别抑制酶活力（％）：     

The efficiency of adaptive search tactics for different prey distribution patterns: a simulation model based on the behaviour of juvenile plaice

Juvenile plaice Pleuronectes platessa are particularly useful for studying forager search behaviour because their search paths are essentially two dimensional, and punctuated by natural stops. Their prey occur in a range of natural distributions from highly aggregated to over‐dispersed. Juvenile plaice use area‐restricted search near aggregated prey and extensive search, consisting of longer moves and fewer turns, between aggregations and when searching for dispersed prey. They search for less conspicuous prey items mainly in the pauses between movements. This saltatory search behaviour contrasts with the continuous search that is usually assumed in search models. A simulation model of saltatory search behaviour showed that a strategy combining extensive and intensive search allows the efficient exploitation of a range of natural prey distribution patterns, and that it is particularly effective when the search behaviour is controlled by perceived prey density. This allows the predator to respond to the localized aggregations which often occur in nature. The selective use of intensive search was more efficient than the continuous use of extensive search even in prey distribution patterns that were statistically over‐dispersed.     

Mate choice and optimal search behavior: Fitness returns under the fixed sample and sequential search strategies

The behavior of a female in search of a mate determines the likelihood that she encounters a high-quality male in the search process. The fixed sample (best-of-n) search strategy and the sequential search (fixed threshold) strategy are two prominent models of search behavior. The sequential search strategy dominates the former strategy—yields an equal or higher expected net fitness return to searchers—when search costs are nontrivial and the distribution of quality among prospective mates is uniform or truncated normal. In this paper our objective is to determine whether there are any search costs or distributions of male quality for which the sequential search strategy is inferior to the fixed sample search strategy. The two search strategies are derived under general conditions in which females evaluate encountered males by inspection of an indicator character that has some functional relationship to male quality. The solutions are identical to the original models when the inspected male attribute is itself male quality. The sequential search strategy is shown to dominate the fixed sample search strategy for all search costs and distributions of male quality. Low search costs have been implicated to explain empirical observations that are consistent with the use of a fixed sample search strategy, but under conditions in which the original models were derived there is no search cost or distribution of male quality that favors the fixed sample search strategy. Plausible alternative explanations for the apparent use of this search strategy are discussed.     

Simulated Evolutionary Optimization and Local Search: Introduction and Application to Tree Search

Tree search and its more complicated variant, tree search and simultaneous multiple DNA sequence alignment, are difficult NP-complete optimization problems, which require the application of advanced computational techniques, if large data sets are to be solved within reasonable computation times. Traditionally tree search has been attacked with a search strategy that is best described as multistart hill-climbing; local search by branch swapping has been performed on several different starting trees. Recently a different tree search strategy was tested in the Parsigal parsimony program, which used a combination of evolutionary optimization and local search. Evolutionary optimization algorithms use principles adopted from biological evolution to solve technical optimization tasks. Evolutionary optimization is a stochastic global search method, which means that the method is able to escape local optima, and is in principle able to produce any solution in the search space (although this may take a long time). Local search techniques, such as branch swapping, employ a completely different search strategy; they exploit local information maximally in order to achieve quick improvement in the value of the objective function. However, local search algorithms lack the ability to escape from local optima, which is a fundamental requirement for any search algorithm that aims to be able to discover the global optimum of a multimodal optimization problem. Hence it seems that an optimization strategy combining the good properties of both evolutionary algorithms and local search would be ideal. In this study, aspects of global optimization and local search are discussed, and the method of simulated evolutionary optimization is reviewed in detail. The application of simulated evolutionary optimization to tree search in Parsigal is then reviewed briefly.     

Sources of variability in the transition from extensive to intensive search in coccinellid predators (Homoptera: Coccinellidae)

In an environment structured by habitats, prey patches, and prey, predators such as coccinellids have two movement modes. The extensive search and the intensive search which results from prey capture are adopted for patch localization and exploration, respectively. The variability of changes from extensive search to intensive search was studied in larvae of the aphidophagous coccinellidSemiadalia undecimpunctata to find out their possibility of adaptation to a fluctuating environment. The temporal organization of coccinellid movements appears far more complicated than the generally accepted succession of extensive search, feeding, and intensive search. Their paths are characterized by the presence of time intervals devoted to intensive search before feeding, a highly variable path response after prey consumption (larvae may adopt intensive search immediately, later, or never), and the alternation of time periods devoted to either extensive search or intensive search after prey ingestion. This interindividual variability suggests that coccinellids have the ability to adapt to heterogeneity or short-term changes in environmental conditions, particularly in prey distribution. These results are in favor of the use of these predators in biological control programs.     

Guiding conformation space search with an all-atom energy potential

The most significant impediment for protein structure prediction is the inadequacy of conformation space search. Conformation space is too large and the energy landscape too rugged for existing search methods to consistently find near-optimal minima. To alleviate this problem, we present model-based search, a novel conformation space search method. Model-based search uses highly accurate information obtained during search to build an approximate, partial model of the energy landscape. Model-based search aggregates information in the model as it progresses, and in turn uses this information to guide exploration toward regions most likely to contain a near-optimal minimum. We validate our method by predicting the structure of 32 proteins, ranging in length from 49 to 213 amino acids. Our results demonstrate that model-based search is more effective at finding low-energy conformations in high-dimensional conformation spaces than existing search methods. The reduction in energy translates into structure predictions of increased accuracy.     

Missing Links in Middle School: Developing Use of Disciplinary Relatedness in Evaluating Internet Search Results

In the “digital native” generation, internet search engines are a commonly used source of information. However, adolescents may fail to recognize relevant search results when they are related in discipline to the search topic but lack other cues. Middle school students, high school students, and adults rated simulated search results for relevance to the search topic. The search results were designed to contrast deep discipline-based relationships with lexical similarity to the search topic. Results suggest that the ability to recognize disciplinary relatedness without supporting cues may continue to develop into high school. Despite frequent search engine usage, younger adolescents may require additional support to make the most of the information available to them.     

Saltatory search in a lateral line predator

The dwarf scorpionfish Scorpaena papillosa detected the hydrodynamic signals produced by prey with the mechanosensory lateral line. This species displayed a pause and move search pattern that is consistent with a saltatory search. The pause phase of the search cycle was probably used to detect prey because pauses often ended early in order to initiate an approach at prey and prey were detected throughout the search space. The move phase of the search cycle repositioned the fish so that it moved approximately a third of the reactive distance. Move distance was found to be the most important factor in gaining novel search space. Turning was shown to be relatively unimportant in gaining novel search space with a high frequency of low turn angles made by the fish. The dwarf scorpionfish, however, exhibited a spiralling or looping pattern over a search path exhibiting a turn bias towards either the left or right. The dwarf scorpionfish adopted a search behaviour that is consistent with a saltatory search and efficient for lateral line predation.     

Evolutionary search: Gradients and information

To better understand evolution one might view evolution as a search algorithm proceeding through a search space. The search method implemented by reproduction with mutation and selection of the fit does not perform efficiently on many search spaces. Characteristics of the search space are critically important to the effectiveness of the search algorithm. The “gradients” of and the “information” in a search space are used in this paper to study performance of “evolutionary” search algorithms.     

Molecular Characterization of the Calvin Cycle Enzyme Phosphoribulokinase in the Stramenopile Alga Vaucheria litorea and the Plastid Hosting Mollusc Elysia chlorotica

Phosphoribulokinase （PRK）, a nuclear-encoded plastid-localized enzyme unique to the photosynthetic carbon reduction （Calvin） cycle, was cloned and characterized from the stramenopile alga Vaucheria litorea. This alga is the source of plastids for the mollusc （sea slug） Elysia chlorotica which enable the animal to survive for months solely by photoautotrophic CO2 fixation. The 1633-bp V. litorea prk gene was cloned and the coding region, found to be interrupted by four introns, encodes a 405-amino acid protein. This protein contains the typical bipartite target sequence expected of nuclearencoded proteins that are directed to complex （i.e. four membrane-bound） algal plastids. De novo synthesis of PRK and enzyme activity were detected in E. chlorotica in spite of having been starved of V. litorea for several months. Unlike the algal enzyme, PRK in the sea slug did not exhibit redox regulation. Two copies of partial PRK-encoding genes were isolated from both sea slug and aposymbiotic sea slug egg DNA using PCR. Each copy contains the nucleotide region spanning exon 1 and part of exon 2 of V litorea prk, including the bipartite targeting peptide. However, the larger prk fragment also includes intron 1. The exon and intron sequences of prk in E. chlorotica and V/itorea are nearly identical. These data suggest that PRK is differentially regulated in V. litorea and E. chlorotica and at least a portion of the V. litorea nuclear PRK gene is present in sea slugs that have been starved for several months.     

Identification,expression, and characterization of the highly conserved D-xylose isomerase in animals

D-xylose is a necessary sugar for animals. The xylanase from a mollusk, Ampullaria crossean, was previously reported by our laboratory. This xylanase can degrade the xylan into D-xylose. But there is still a gap in our knowledge on its metabolic pathway. The question is how does the xylose enter the pentose pathway？ With the help of genomic databases and bioinformatic tools, we found that some animals, such as bacteria, have a highly conserved D-xylose isomerase （EC 5.3.1.5）. The xyiose isomerase from a sea squirt, Ciona intestinali, was heterogeneously expressed in Escherichia coli and purified to confirm its function. The recombinant enzyme had good thermal stability in the presence of Mg^2＋. At the optimum temperature and optimum pH environment, its specific activity on D-xylose was 0.331 μmol/mg/min. This enzyme exists broadly in many animals, but it disappeared in the genome of Amphibia-like Xenopus laevis. Its sequence was highly conserved. The xylose isomerases from animals are very interesting proteins for the study of evolution.