纳米细菌及其诱发肾结石形成的研究进展

纳米细菌是近年来新发现的一种直径为纳米级且具有矿化能力的细菌。在肾结石形成过程中,纳米细菌可以作为结晶的活性中心,黏附、侵入并破坏肾集合管的上皮细胞和肾乳头细胞,形成磷灰石晶核,从而诱发肾结石形成。综述了肾结石中的纳米细菌及其诱发肾结石形成的体外模拟和动物学模型,讨论了纳米细菌与肾结石形成的关系。     

对德氏乳杆菌DM8909菌株的发酵工艺研究

德氏乳杆菌 DM890 9菌株是大连医科大学微生态学研究所分离驯化的一株兼性厌氧菌 ,主要用于防治非特异性阴道炎等妇科疾病。本实验通过对德氏乳杆菌 DM890 9菌株进行摇瓶、小型全自动发酵罐和 5 0 0 L发酵罐发酵工艺学研究 ,考察其发酵工艺中试条件。现将研究结果报告如下 :1　材料与方法1.1　菌种　本研究所使用的菌种德氏乳杆菌 DM890 9(L actobacillus debrueckii subsp.lactis)由大连医科大学微生态学研究所提供。1.2　培养基　摇瓶种子培养基、小罐发酵培养基及大罐发酵培养基均采用 L BS培养基。1.3　培养方法1.3.1　摇瓶培养　…     

对乳杆菌DM8909菌株质粒的检测

德氏乳杆菌乳酸变种（ＬａｃｔｏｂａｃｉｌｕｓｄｅｂｒｕｅｃｋｉＳｕｐｓｐ．ｌａｃｔｉｓ）是阴道正常菌群成员之一,探讨该菌株是否存在质粒对于研究乳杆菌耐药性具有一定意义。现将ＤＭ８９０９质粒检测情况报告如下。１材料与方法１１菌株与培养基菌株德氏乳杆...     

乳酸菌DM9054、DM9057的安全性评价

目的实验评价的2株乳酸菌DM9054和DM9057均分离于泡菜,分别具有降胆固醇和降血压功能,由于其功能性强,性状优良,故本实验对其安全性进行评价,为应用于食品药品生产提供参考依据。方法通过急性毒性试验、耐药性、机体指标、有害代谢产物的评价试验以及其他安全性评价试验检测两实验菌株的安全性。结果在一次性分别使用DM9054和DM9057大剂量灌胃后,动物体征指标无异常;两菌株对部分抗生素具有抗性,但不携带可转移的耐药质粒;使用实验菌株后,机体指标MDA、GSH和SAA的变化基本正常;菌株代谢不产生胆盐羟化酶、硝基还原酶和氨基脱羧酶,但产生乳酸;无溶血作用,长期使用,不发生易位现象。结论乳酸菌DM9054和DM9057总体上是安全的。     

纳米细菌及其诱发肾结石形成的研究进展*

纳米细菌是近年来新发现的一种直径为纳米级且具有矿化能力的细菌。在肾结石形成过程中,纳米细菌可以作为结晶的活性中心,黏附、侵入并破坏肾集合管的上皮细胞和肾乳头细胞,形成磷灰石晶核,从而诱发肾结石形成。综述了肾结石中的纳米细菌及其诱发肾结石形成的体外模拟和动物学模型,讨论了纳米细菌与肾结石形成的关系。     

原生质体融合技术选育分解草酸乳酸菌菌株的研究

将具有草酸分解能力的乳双歧杆菌和具有耐氧特性的嗜酸乳杆菌进行原生质体融合,其最佳条件为:50%的PEG6000,融合温度30℃,融合时间为7 min,CaCl2浓度为0.02 mol/L,MgCl2浓度为0.5 mol/L,在此条件下融合率可达7.6%。从中筛选出同时具有耐氧特性和草酸分解能力的融合子,草酸分解率为13.4%。     

产广谱乳酸菌素菌株的选育、鉴定及其发酵特性研究

在传统发酵食品中分离得到产酸茵株50株,从中筛选出一株产广谱乳酸菌素菌株,经鉴定是植物乳杆菌。实验对该菌株产乳酸菌素发酵培养基的优化结果为:牛肉膏2%,酵母粉0.75%,蔗糖2.5%,柠檬酸三铵0.2%,乙酸钠0.5%,K_2HPO_40.4%,MgSO_4·7H_2O 0.058%,MnSO_4·4H_2O 0.025%;最佳发酵条件为:35℃,初始pH值6.0,添加2%的吐温80。在此条件下,菌株的抑菌圈直径可达3.15 cm。     

对德氏乳杆菌DM8909菌株的微生物学研究

通过对阴道正常菌群定性、定量研究表明 ,乳杆菌在阴道正常菌群中的检出率和数量都占有绝对优势 ,并对致病菌有拮抗作用。乳杆菌对维持阴道微环境 ,保持其健康状态具有重要意义 ,乳杆菌作为阴道病防治的微生态调节剂应用具有广泛的应用前景。本文就阴道乳杆菌的分离、生化反应特征、代谢产物分析及菌种鉴定等微生物学研究工作报道如下。1　材料与方法1 .1　菌种的分离方法　根据文献及本课题的阴道菌群与微生态疗法的研究结果 [1] ,确定乳杆菌为选种对象。用阴道拭子取阴道分泌物 ,接种于 Lbs培养基上 ,37℃培养 72 h。根据乳杆菌的特征筛…     

对德氏乳杆菌DM8909菌株的药理学研究

由大连医科大学微生态学研究所从阴道中分离的德氏乳杆菌 DM890 9菌株经实验证明 ,其具有产乳酸和 H2 O2 的能力。为研究本菌株是否具有继续开发的前景 ,我们对其毒性及一般药理学进行了研究 ,现报告如下 :1　材料与方法1 .1　菌种及菌粉来源　实验采用的菌种是德氏乳杆菌 DM890 9菌株 ,其实验用菌粉系采用 DM890 9菌株经小罐发酵、离心分离、冷冻干燥、乳糖稀释制成 ,均由大连医科大学微生态学研究所提供。1 .2　急性毒性试验1 .2 .1　实验动物　昆明种小鼠 ,体重 ( 2 0± 2 ) g,雌雄兼用 ,共 5 0只 ,随机分成 5个剂量组 ,每组 1 0只。…     

鼠李糖乳杆菌LV108及其发酵乳免疫调节作用的比较

目的 探讨鼠李糖乳杆菌LV108及其发酵乳对免疫抑制小鼠免疫功能的调节作用。 方法 将BALB/c小鼠随机分为5组,每组10只,即空白组(正常小鼠)、模型组(免疫抑制小鼠)、药物组(免疫抑制小鼠食物中添加左旋咪唑)、LV108菌悬液组(免疫抑制小鼠食物中添加LV108菌悬液)和LV108发酵乳组(免疫抑制小鼠食物中添加LV108发酵乳),除空白组外其余组构建免疫抑制小鼠模型。干预4周后,分别测定各组小鼠体质量和脏器指数,血清中白细胞介素2(IL2)、肿瘤坏死因子α(TNFα)和免疫球蛋白G(IgG)含量,血清溶血素含量、耳肿胀度和肝、脾巨噬细胞吞噬能力。 结果 相比模型组,LV108菌悬液组和LV108发酵乳组小鼠体质量增长速度、脏器指数、血清IL2与IgG水平、血清溶血值、耳肿胀度和巨噬细胞吞噬能力显著升高(均P结论 LV108菌体及发酵乳对免疫抑制小鼠具备较全面的免疫调节作用,均可提高小鼠的自身免疫力;LV108发酵乳对小鼠的免疫调节作用强于LV108菌体。     

乳杆菌在发酵乳饮料中的应用

为了制备更优质的乳酸菌饮料,本论文主要以鼠李糖乳杆菌、瑞士乳杆菌、副干酪乳杆菌、嗜酸乳杆菌四种典型的乳酸杆菌为研究菌种,详细分析它们在乳品发酵过程中pH、酸度变化,货架期内的活菌数变化以及代谢产生的有机酸种类和耐胃酸的能力,以确定乳杆菌在乳饮料中应用的最优条件,分析其应用于乳饮料中的可行性。本文为乳杆菌在乳饮料中的应用提供了参考依据。     

Ceftriaxone crystallization and its potential role in kidney stone formation

Drug-induced nephrolithiasis contributes to 1–2% of the incidence of renal calculi. We examined whether ceftriaxone at therapeutic doses could be crystallized in the urine and also explored its role in kidney stone formation. Crystallization was induced by mixing ceftriaxone sodium at therapeutic urinary excretion levels (0.5–4.0 mg/ml) to calcium chloride at physiologic urinary concentration (5 mM) in deionized (dI) water or artificial urine (AU). The results showed that ceftriaxone was crystallized with free calcium in dose- and time-dependent manner. These ceftriaxone/calcium crystals showed birefringence property under polarized microscope. Individual crystals had needle-shape (5–100 μm in length), whereas the aggregated form had star-burst and irregular-plate shape (40–200 μm in diameter) (note that the crystal sizes were much larger than renal tubular lumens). Calcium-depletion assay revealed that crystallization required free calcium as a substrate. In AU, crystallization remained although it was partially inhibited when compared to that in dI water. Finally, these crystals could tightly adhere onto renal tubular cell surface. Our data demonstrated that ceftriaxone at therapeutic levels could be crystallized with free calcium in the urine under physiologic condition. We hypothesize that tubular occlusion and crystal–cell adhesion may play important role in pathogenic mechanisms of ceftriaxone-induced nephrolithiasis.     

Effects of Lactobacillus helveticus fermented milk on bone cells in vitro

Milk fermented with Lactobacillus helveticus (L. helveticus) contains small peptides such as isoleucyl-prolyl-proline (IPP) and valyl-prolyl-proline (VPP), which inhibit the angiotensin converting enzyme (ACE). We investigated the effects of L. helveticus fermented milk whey (Lh-whey) and its components, sour milk whey, calcium and IPP and VPP peptides, on bone cells in vitro. An osteoblast assay was performed by determining the amount of deposited calcium as an index of bone formation in cultures of mouse osteoblasts formed from bone marrow-derived osteoblast precursor cells. An osteoclast assay was performed by determining the activity of tartrate-resistant acid phosphatase released into the culture medium in cultures of mouse osteoclasts formed from bone marrow-derived osteoclast precursor cells. The Lh-whey increased bone formation 1.3-1.4 times with the 1 × 10⁻⁵, 1 × 10⁻⁴ and 1 × 10⁻³ solutions. The IPP and VPP peptides also demonstrated a significant 5-fold activation of bone formation in in vitro osteoblast cultures, whereas the sour milk whey and calcium had no effect. No significant effects were observed on osteoclasts in vitro with any of the study products. L. helveticus fermented milk whey contains bioactive components that increase osteoblastic bone formation in vitro. The effect may be due to the ACE-inhibitory IPP and VPP peptides, which showed a similar effect to that of the L. helveticus fermented milk whey.     

Selective enumeration of Lactobacillus casei from yogurts and fermented milk drinks

A selective medium (LC agar) was developed for enumeration of Lactobacillus casei populations from commercial yogurts and fermented milk drinks that may contain strains of yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus), probiotic bacteria (Lactobacillus acidophilus and bifidobacteria) and L. casei. Appropriate dilutions were pour-plated in specially formulated LC agar acidified to pH 5.1 and the plates incubated at 27°C for 72 to 96 h under anaerobic conditions. Growth of S. thermophilus was prevented by adjusting pH to 5.1. L. delbrueckii ssp. bulgaricus did not ferment ribose as the carbon source, as a result the organisms did not form colonies. L. acidophilus formed colonies on MRS-ribose agar; however, this organism did not grow in the specially formulated LC agar containing ribose. Similarly, Bifidobacterium spp. did not form colonies in LC agar. L. casei formed colonies on LC agar. © Rapid Science Ltd. 1998     

降血压乳酸菌发酵乳对原发性高血压大鼠的降压效果

目的对具有血管紧张素转化酶(ACE)抑制活性的乳酸菌DM9057发酵乳的抗胃肠道酶解能力及原发性高血压大鼠(SHR)体内降压效果进行研究。方法以10 ml/kg和2.5 ml/kg发酵乳一次性和连续灌胃原发性高血压大鼠。结果 DM9057发酵乳具有较好的抗胃肠道酶能力,并且2个剂量均具有较好的降血压效果,其中以10 ml/kg剂量效果最为显著,一次性和连续灌胃后,最大降压值为(17.97±3.82)、(25.46±5.06)mmHg。结论乳酸菌DM9057发酵乳具有较强的抗胃肠道能力,同时在原发性高血压大鼠体内能够发挥一定的降血压作用。     

Survival of Lactobacillus casei in the human digestive tract after consumption of fermented milk

A human trial was carried out to assess the ileal and fecal survival of Lactobacillus casei DN-114 001 ingested in fermented milk. Survival rates were up to 51.2% in the ileum and 28.4% in the feces. The probiotic bacterium has the capacity to survive during its transit through the human gut.     

Identification and differentiation of Lactobacillus, Streptococcus and Bifidobacterium species in fermented milk products with bifidobacteria

The aim of this study was to identify and discriminate bacteria contained in commercial fermented milks with bifidobacteria by the use of amplified ribosomal DNA restriction analysis (ARDRA) and randomly amplified polymorphic DNA (RAPD) techniques. ARDRA of the 16S rDNA gene and RAPD were performed on 13 Lactobacillus strains, 13 Streptococcus and 13 Bifidobacterium strains isolated from commercial fermented milk. Lactobacillus delbrueckii, Streptococcus thermophilus and Bifidobacterium animalis isolates were identified by genus- and species-PCR and also, they were differentiated at genus and species level by ARDRA using MwoI restriction enzyme. The ARDRA technique allowed for the discrimination among these three related genus with the use of only one restriction enzyme, since distinctive profiles were obtained for each genus. Therefore it can be a simple, rapid and useful method for routine identification. Also, RAPD technique allowed the discrimination of all bacteria contained in dairy products, at genus- and strain-level by the performance of one PCR reaction.