单增李斯特菌胎盘感染的体内外模型研究进展

单核细胞增生李斯特氏菌（Listeria monocytogenes）是重要的食源性致病菌,能引发人类的李斯特菌病,是全球公共卫生问题之一。该菌易感染孕妇,引起胎儿和新生儿的侵袭性李斯特菌病,严重威胁母婴健康。因此,建立有效的单增李斯特菌感染胎盘体内外模型,解析和探究单增李斯特菌经胎盘感染机制,是预防和控制单增李斯特菌感染母婴的关键所在。本文综述了可用于研究单增李斯特菌母婴感染的体内外胎盘模型,总结和讨论了各类模型的优势和局限性;并着重分析了体外三维胎盘屏障模型在单增李斯特菌感染方面的研究进展和未来研究方向。以期为深入解析该菌经胎盘感染的途径、发病机制提供支持,并为预防和控制母婴李斯特菌病提供科学参考。     

睡菜离体快繁技术的研究

以睡菜的幼嫩茎段为外植体,接种到附加不同浓度激素配比(6-BA/NAA)的MS培养基,诱导睡菜愈伤组织、芽及根的生长。研究发现,外植体在1.0mg/L 6-BA+0.1mg/L NAA+MS的培养基上培养10d,可观察到浅绿色的愈伤组织。愈伤组织转接到4.0mg/L 6-BA+0.3mg/L NAA+MS培养基上2周左右可生成芽。对带芽的愈伤组织再进行诱导生根进而形成完整再生植株,最适根诱导培养基为0.3mg/L 6-BA+1.0mg/L NAA+MS培养基。该实验采用植物离体快繁技术成功建立了睡菜再生体系,为睡菜种苗规模化奠定了技术基础。     

狭叶薰衣草的离体培养及挥发性成分的分析

为建立新疆狭叶薰衣草(Lavandula angustifolia)的快速繁殖体系,以种子、茎、叶为外植体,对种子萌发、愈伤组织诱导、丛芽分化和生根的最适培养条件进行了研究;用水蒸气蒸馏法提取狭叶薰衣草挥发油,采用气相色谱-质谱法测定挥发油成分。结果表明,种子浸泡的适宜时间为6 h,切开种皮培养,出芽时间最少为6 d;诱导种子出芽的适宜培养基为MS+6-BA2 mg/L;以茎为外植体诱导愈伤组织效果较好,适宜培养基为MS+6-BA 2 mg/L+2,4-D 1 mg/L;诱导分化丛芽的适宜培养基为MS+6-BA 1 mg/L+NAA 0.5 mg/L;生根的适宜培养基为1/2MS+NAA 1 mg/L+6-BA 0.5 mg/L;盆栽薰衣草和无菌苗薰衣草的挥发油主要成分相差较大,离体培养的薰衣草的主要挥发性成分有叶绿醇、丁香油烃、氧化石竹烯等。     

Kavalactones fail to inhibit alcohol dehydrogenase in vitro

In recent years, Kava kava (Piper methysticum, Forst. f., Piperaceae), a folkloric beverage and popular herbal remedy, has been implicated in a number of liver failure cases. Many hypotheses as to the mechanism of its hepatotoxicity, for example interactions with other co-ingested medication, have been postulated. This present study investigated whether pharmacokinetic interactions between kava constituents and alcohol via alcohol dehydrogenase (ADH) inhibition by individual kavalactones might explain its claimed hepatotoxic effects. Four kavalactones, (+/-)-kavain, methysticin, yangonin and desmethoxyyangonin, fail to inhibit ADH in vitro at 1, 10 or 100 microM concentrations.     

酸枣果提取物在体内外对抗生素的增效作用及机制研究

作者研究团队先前从酸枣果的氯仿提取物中精制得到其低极性范围的活性组合物Fr.2a,发现Fr.2a与多种抗生素联用显示出广泛的协同抗菌作用。该研究在Fr.2a的基础上利用硅胶柱层析对酸枣果氯仿提取物中其他极性范围内的活性成分进行了分离纯化,得到精制物Fr.B,并对精制物Fr.B进行GC MS、核磁共振氢谱、红外光谱分析,以确定Fr.B的组成成分;通过抗菌谱分析和细胞通透性分析,以明确Fr.B的抗菌增效谱和抗菌增效机制;采用熔和法将精制物Fr.B制备成软膏,通过小鼠伤口感染模型评价该软膏对抗生素的增效效果。结果表明：(1)由酸枣果氯仿提取物进一步精制得到的Fr.B组分,主要包含反油酸、油酸、顺 10 十六碳烯醇、棕榈酸等脂肪酸类化合物。(2)Fr.B分别与庆大霉素、妥布霉素、氨苄青霉素、氯霉素、红霉素、夫西地酸、制霉菌素、酮康唑和两性霉素B等多种抗生素联用时显示出广泛的协同抗菌作用。(3)Fr.B可破坏细胞膜和细胞壁的完整性而增强细菌细胞的通透性。(4)在体内和体外Fr.B均能显著增强红霉素对耐甲氧西林金黄色葡萄球菌(MRSA)的杀菌作用,从而提高红霉素对MRSA菌株引起的伤口感染的治疗效果。研究表明,本研究所得到的Fr.B具有广谱的抗菌增效活性,能够增强红霉素对伤口耐药菌感染的治疗效果。该研究结果为克服微生物对抗生素的耐药性提供了新的思路和解决方案。     

Schistosoma mansoni: Schistosomicidal effect of mefloquine and primaquine in vitro

We investigated the effects of the anti-malarials mefloquine and primaquine against the juvenile and adult life stages of Schistosoma mansoniin vitro. Cercariae were incubated with 0.5 μg/ml, 1 μg/ml and 2 μg/ml mefloquine or primaquine and with 1 μg/ml praziquantel for 12 h. Schistosomula, pre-adults and adults were incubated with 0.5 μg/ml, 1 μg/ml and 2 μg/ml mefloquine or primaquine and with 1 μg/ml praziquantel for 7 days. The viability status was classified as viable, damaged or dead and was checked every 3 h for cercariae and every 12 h for schistosomula, pre-adults and adults. Both, mefloquine and primaquine show time and dose-dependent schistosomicidal effects on the four life stages of S. mansoni. The promising in vitro effects on all stages of the blood fluke S. mansoni warrants further evaluation of both anti-malarials and their derivatives for their prophylactic and therapeutic values in early and late schistosomiasis in field trials.     

黄芩苷对嗜水气单胞菌生物膜形成的影响及体内外的抑菌作用

[目的]探讨中药单体黄芩苷对嗜水气单胞菌在体内外生长及生物膜形成的影响.[方法]体外实验中,利用牛津杯法检测抑菌圈直径,结晶紫法检测生物膜的形成,通过泳动实验检测黄芩苷对嗜水气单胞菌运动性的影响,紫外吸收法检测细胞膜完整性,用透射电镜技术观察黄芩苷对细菌形态的影响.体内实验利用草鱼为对象检测黄芩苷对嗜水气单胞菌增殖的影...     

广西五种绞股蓝属植物离体快繁与种质保存研究

以绞股蓝属植物的带芽茎段为材料,研究不同6-BA浓度与NAA 0.02mg·L-1组合对其诱导、分化和增殖的影响,并建立离体快繁体系。结果表明:MS+6-BA 2.0mg·L-1+NAA 0.02mg·L-1最适宜初代诱导,MS+6-BA 2.0mg·L-1+NAA 0.02mg·L-1最适合扁果绞股蓝的增殖培养,而MS+6-BA 1.5mg·L-1+NAA0.02mg·L-1是其它四种植物增殖的最佳培养基,在1/2MS+NAA 1.0mg·L-1上的生根率均达100%。1/2MS与蔗糖40g·L-1对五种植物的保存效果均最好;添加生长抑制剂能有效减缓生长速度,最佳生长抑制剂为ABA和CCC,浓度均为1.0mg·L-1,其中CCC能适合多个物种,连续保存360d的存活率均在94.5%以上;PP333不适合五种植物的保存。活力检测表明,各种质经保存后增殖、生根能力均未下降。     

多糖类益生元的筛选及凝结芽孢杆菌体外发酵特性北大核心

【目的】探究9种多糖对凝结芽孢杆菌(Bacillus coagulans)的增殖、产酶特性的影响。【方法】将凝结芽孢杆菌分别添加至菊粉多糖(inulin polysaccharide)、刺五加多糖(Eleutherococcus senticosus polysaccharide)、壳寡糖(chitosan oligosaccharide)、防风多糖(Saposhnikovia divaricata polysaccharide)、低聚木糖(xylo-oligosaccharide)、黄芪多糖(Astragalus polysaccharide)、甘露糖(D-mannose)、白术多糖(Atractylodes macrocephala Koidz polysaccharide)和玉屏风多糖(Yu Ping Feng polysaccharide)为唯一碳源的培养基中,通过菌株生长、酶活性及其体外厌氧发酵等作为指标,筛选出最优益生元。【结果】凝结芽孢杆菌能很好地利用防风多糖、黄芪多糖、白术多糖和玉屏风多糖;添加量为4%的防风多糖和白术多糖,pH差值差异最大,蛋白酶活性差异显著(P<0.05)。体外发酵乳酸活性和总蛋白酶活性均提高,4%白术多糖的乳酸和总蛋白酶活性差异显著(P<0.05);肠道内容物发酵液16S rRNA基因高通量测序结果表明,与对照组比较,添加黄芪多糖、防风多糖、甘露糖3种益生元发酵凝结芽孢杆菌显著降低了气单胞菌(Aeromonas)、α-变形菌(α-Proteobacteria)、链球菌(Streptococcus)、志贺氏杆菌属(Shigella)等致病菌的相对丰度,提高了乳杆菌(Lactobacillus)、厚壁菌门(Firmicutes)、乳酸乳球菌(Lactococcus lactis)、产酸杆菌(Acidobacteria)的相对丰度。【结论】凝结芽孢杆菌发酵4%白术多糖具有较好的产酶性能与益生特性,二者协同发酵添加至饲料中具有较好的发展潜力。     

无距虾脊兰花粉离体萌发及储藏条件的研究

以天目山野生无距虾脊兰的花粉为材料,采用离体萌发法研究了花粉的储藏性以及不同的培养基组分和培养条件对花粉萌发和花粉管生长的影响,并采用联苯胺-过氧化氢法测定了其柱头的可授性,以筛选无距虾脊兰花粉的培养方法以及储藏条件,为其种质资源保存等研究奠定基础。结果表明:(1)无距虾脊兰最适花粉液体培养基为200g·L-1蔗糖+50mg·L-1 H3BO3+40mg·L-1 Ca(NO3)2·4H2O,并且在pH 5.5~6.0、温度25℃恒温下培养48h,无距虾脊兰花粉萌发率(81.71%)和花粉管生长(247.42μm)最佳。(2)无距虾脊兰花粉在-80℃中低温干燥储藏360d后仍具有48.58%的萌发率。(3)无距虾脊兰的柱头在开花前5d内均具有可授性,花粉块在整个花期内均保持了28.96%~81.71%的生活力,但柱头可授性和花粉活力均随开花后时间的延长显著降低。     

Keratan sulfate and related murine glycosylation can suppress murine cartilage damage in vitro and in vivo

Keratan sulfate (KS) proteoglycan side chains are abundant in the human cartilage matrix, but these chains have been said to be absent in murine skeletal tissues. We previously showed that KS suppresses cartilage damage and ameliorates inflammation in mice arthritis model. Because mice deficient of N-acetylglucosamine 6-O-sulfotransferase-1 (GlcNAc6ST-1) (KS biosynthesis enzyme) are now available, we decided to do further examinations.We examined, in culture, the difference between GlcNAc6ST-1^−/− and wild-type (WT) mice for interleukin (IL)-1α-induced glycosaminoglycan (GAG) release from the articular cartilage. Arthritis was induced by intravenous administration of an anti-type II collagen antibody cocktail and subsequent intraperitoneal injection of lipopolysaccharide. We examined the differences in arthritis severities in the two genotypes. After intraperitoneal KS administration in phosphate-buffered saline (PBS) or PBS alone, we evaluated the potential of KS in ameliorating arthritis and protecting against cartilage damage in deficient mice.GAG release induced by IL-1α in the explants, and severity of arthritis were greater in GlcNAc6ST-1^−/− mice than their WT littermates. Intraperitoneal KS administration effectively suppressed arthritis induction in GlcNAc6ST-1^−/− mice. Thus, GlcNAc6ST-1^−/− mice cartilage is more fragile than WT mice cartilage, and exogenous KS can suppress arthritis induction in GlcNAc6ST-1^−/− mice. Vestigial KS chain or altered glycosylation in articular cartilage in GlcNAc6ST-1^−/− mice may be protective against arthritis and associated cartilage damage as well as cartilage damage in culture. KS may offer therapeutic opportunities for chondroprotection and suppression of joint damage in inflammatory arthritis and may become a therapeutic agent for treating rheumatoid arthritis.     

CaXMT和TCS1突变体基因串联共表达及体外酶活检测分析

咖啡碱和可可碱是茶叶生物碱的主要组分,且咖啡碱是茶叶重要的滋味物质,随着咖啡碱在食品和药物领域的应用愈发广泛,咖啡碱的生物合成成为新的研究热点.目前市场上的咖啡碱主要靠化学合成,为了探索其生物合成途径,该研究将咖啡黄嘌呤核苷甲基转移酶(coffee xanthosine methyltransferase,CaXMT)基因和茶树咖啡碱合成酶(tea caffeine synthase,TCS1)基因的4个突变体分别串联至同一大肠杆菌表达载体pMAL-c5X,诱导融合蛋白共表达,并进行SDS-PAGE凝胶电泳分析.结果表明:目的蛋白成功表达后,应用超声破碎法制备含有目的蛋白的粗酶液,添加底物黄嘌呤核苷(xanthosine,XR)和甲基供体S-腺苷甲硫氨酸(S-adenosyl-L-methionine,SAM)进行体外酶促反应,将反应产物进行高效液相色谱检测.检测结果显示,pMAL-CaXMT-TM2/3/4的体外酶促反应产物仅有可可碱生成,均未见咖啡碱生成.该研究结果为构建生物合成咖啡碱和可可碱的串联共表达载体奠定了基础,也为进一步研究生物合成咖啡碱和可可碱提供了新思路.     

Antiproliferative activity and induction of apoptosis in human colon cancer cells treated in vitro with constituents of a product derived from Pistacia lentiscus L. var. chia

In this report, we demonstrate that a 50% ethanol extract of the plant-derived product, Chios mastic gum (CMG), contains compounds which inhibit proliferation and induce death of HCT116 human colon cancer cells in vitro. CMG-treatment induces cell arrest at G(1), detachment of the cells from the substrate, activation of pro-caspases-8, -9 and -3, and causes several morphological changes typical of apoptosis in cell organelles. These events, furthermore, are time- and dose-dependent, but p53- and p21-independent. Apoptosis induction by CMG is not inhibited in HCT116 cell clones expressing high levels of the anti-apoptotic protein, Bcl-2, or dominant-negative FADD, thereby indicating that CMG induces cell death via a yet-to-be identified pathway, unrelated to the death receptor- and mitochondrion-dependent pathways. The findings presented here suggest that CMG (a) induces an anoikis form of cell death in HCT116 colon cancer cells that includes events associated with caspase-dependent pathways; and (b) might be developed into a chemotherapeutic agent for the treatment of human colon and other cancers.     

常规培养与缺氧条件下BCG菌体内外sRNA的表达检测

近期发现细菌的sRNA在菌体内和菌体外均具有一定的生物学功能.为研究结核分枝杆菌菌体内外sRNA的表达情况,通过分析卡介苗(Bacillus Calmette-Guerin Vaccine,BCG)菌体和外泌体RNA测序结果,采用RT-qPCR法检测常规培养与缺氧条件下BCG菌体内外sRNA相对表达量,分析菌体内外sR...     

Plant stress uncoupling protein CSP 310 caused thermogenesis in winter wheat mitochondria in vitro

The addition of plant stress uncoupling protein CSP 310 has been found to increase thermogenesis in isolated winter wheat mitochondriain vitro during cold stress. On the other hand, the addition of anti-CSP 310 antiserum has been found to decrease thermogenesis in isolated winter wheat mitochondria. This result corresponds well to data about the influence of mitochondria incubation with CSP 310 and anti-CSP 310 antiserum on their energetic activity. It is supposed that CSP 310 uncouples the oxidative phosphorylation in mitochondria that causes thermogenesis during cold stress.     

二化螟APN1的原核表达及其与Cry2Aa蛋白的结合特性研究

【目的】Bt杀虫蛋白发挥杀虫活性的重要前提是Cry蛋白能够与昆虫中肠上皮细胞刷状缘膜囊(BBMVs)上的受体蛋白结合。在前期获得二化螟氨肽酶N1(Aminopeptidase N,APN1)基因全长序列的基础上,明确二化螟APN1多肽片段与Cry2Aa的结合能力。【方法】将二化螟APN1序列片段在大肠杆菌BL21(DE3)中表达,利用蛋白质单向电泳和ligand blotting技术分析二化螟APN1多肽片段与Cry2Aa的结合能力。【结果】重组载体可在表达菌株BL21(DE3)中表达一个约70 ku的蛋白,纯化后的多肽条带单一,纯度较好。Ligand blot分析结果显示,表达的二化螟APN1多肽片段可以与活化的Cry2Aa杀虫蛋白结合,且结合条带随着重组蛋白上样量的降低而减弱。【结论】APN1多肽片段可以与Cry2Aa结合,为阐明APN1基因的功能奠定基础,也为其他Bt蛋白的受体蛋白相关研究提供新的借鉴。     

Schistosoma mansoni: Antischistosomal activity of the four optical isomers and the two racemates of mefloquine on schistosomula and adult worms in vitro and in vivo

Recent studies have shown that mefloquine (MQ) reveals interesting antischistosomal properties. We examined the antischistosomal activities of the erythro and threo isomers and racemates of MQ on newly transformed schistosomula (NTS) and adult Schistosoma mansoni in vitro and in mice harbouring adult S. mansoni. The in vitro effects in the presence and absence of haemin were monitored by means of microcalorimetry, scanning electron microscopy and phenotypic evaluation. Incubation of NTS with the erythro derivatives at concentrations of 3 μg/ml and above resulted in convulsions, granularity, decrease in heat flow, and death while NTS incubated with the threo derivatives were only affected at high concentrations (100 μg/ml). Extensive tegumental alterations, decrease in metabolic activity, viability, and death were observed when adult schistosomes had been exposed to 10 μg/ml of the erythro compounds. Moderate tegumental and viability changes but reduced heat production rates were observed with the threo derivatives at 10 μg/ml. In the presence of haemin, all MQ derivatives showed pronounced antischistosomal properties against adult S. mansoni in vitro. In vivo, MQ derivatives achieved statistically significant total and female worm burden reductions ranging between 65.4% and 100%. The highest total worm burden reductions of 93.4% and 90.2% were observed following treatment with the erythro and threo racemates, respectively. In conclusion, the optical isomers and racemates of MQ show only moderate stereoselectivity, in particular in vivo. Our results may enhance our understanding of the mechanism of action and therapeutic profile of MQ derivates on schistosomes.     

Characterization and biological activity of the main flavonoids from Swiss Chard (Beta vulgaris subspecies cycla)

The molecular components of a phenolic fraction (P2), obtained from liquid chromatography of a Swiss Chard (Beta vulgaris subsp. cycla) extract, were identified using HPLC-ESI-MS/MS. The primary P2 components were: vitexin-2'O-rhamnoside, its demethylated form 2'-xylosylvitexin, isorhamnetin 3-gentiobioside, and rutin. P2 "in toto" and the single components were characterized for antioxidant capacity, antimitotic activity on MCF-7 human breast cancer cells and for toxicity to human lymphocytes and macrophages. P2 inhibited MCF-7 cell proliferation (IC(50) value = 9 microg/ml) without inducing apoptosis, showed no toxicity to human lymphocytes and slight toxicity to macrophages. Vitexin-2'O-rhamnoside strongly inhibited DNA synthesis in MCF-7 cells, whereas 2'-xylosylvitexin and isorhamnetin 3-gentiobioside were activators; combinations of activators and inhibitors maintained the over-all inhibitory effect.     

蒲公英糖蛋白体内外抗氧化作用研究

为了探讨蒲公英糖蛋白(TMGP)体内外抗氧化活性,采用H2O2、Fe2+、DPPH.和总抗氧化能力反应体系,检测蒲公英糖蛋白体外抗氧化活性,并与VC进行比较;同时建立D-半乳糖所致衰老小鼠模型,测定并比较TMGP组与模型组的血清、肝脏和脑内MDA含量和SOD、CAT、GSH-Px活性。结果显示:(1)随着TMGP浓度增加,其Fe2+、H2O2和DPPH.清除率均有所增加,当TMGP浓度为1.72mg/mL时,对H2O2、Fe2+清除率分别达到76.8%和55%,接近VC水平;当TMGP浓度为1.5mg/mL时,对DPPH.的清除率达到77%,也与VC水平相当,说明TMGP具有一定的体外总体抗氧化能力。(2)将TMGP按低、中、高剂量分别给小白鼠灌胃,可显著增强小鼠体内血清、肝脏、脑组织中SOD、CAT、GSH-Px活性,降低MDA含量,从而提高衰老小白鼠体内的抗氧化能力。研究表明,TMGP具有明显的体内外抗氧化作用。