海滨土壤粘细菌次级代谢产物的性质及产量调控的研究*

黄海边土壤中筛选到具有广谱抑菌活性白色粘细菌So ce cpu-1,次级代谢物活性组分在210nm紫外吸收值最大。研究了不同培养条件对次级代谢产物的产量影响。结果表明,So ce cpu-1在含10％w／v D312中性吸附树脂的M₇培养基中,通氧量为总体积的70％,添加该粘细菌次级代谢产物的粗提物5μL作为诱导物,30℃,200r／min,培养6d,次级代谢产物产量可达到最大值。     

一株新粘细菌生物学性质的研究

对粘细菌纤维堆囊菌So ce cpu-1生物学特性进行了研究.结果表明,该粘细菌能利用如滤纸或玉米秸杆等纤维素.So ce cpu-1次级代谢产物的抑茵实验表明,该粘细菌具有广谱抗菌活性:对人白血病细胞K562有较好的抑制效果.     

粘细菌So ce cpu-1的鉴定及其抗肿瘤活性研究

目的:从土壤中筛选分离粘细菌并研究其抗肿瘤活性。方法:通过对菌的形态和生理生化特征分析确定其种属。通过MTT法研究粘细菌次级代谢物的抗肿瘤活性。结果:分离得到的粘细菌嗜纤维素属Socecpu-1,次级代谢产物具有很好的抗肿瘤活性。结论:该粘细菌的细胞毒作用呈时间依赖性,是潜在的抗肿瘤药物。     

纤维堆囊菌的代谢产物及其生物学活性分析

纤维堆囊菌不同菌株不但表现细胞和子实体形态的差异 ,而且代谢产物的组成和生物学活性也存在差异。纤维堆囊菌对革兰氏阴性细菌不表现任何抑制活性 ,部分菌株可抑制革兰氏阳性细菌 ;但所有菌株对真菌和肿瘤细胞有广泛和强烈的抑制作用。薄层层析显示 ,纤维堆囊菌的次级代谢产物组分较多 ,且大多数组分具有不同程度的抑制真菌和肿瘤细胞的活性。在筛选中发现四株菌的代谢产物能够促进微管蛋白聚合 ,其中So3 3 1活性组分的薄层层析Rf 值与已知的EpothiloneA相似 ,而So81的则有较大的差异。研究结果表明纤维堆囊菌是很好的筛选抗真核生物活性的天然化合物资源。     

粘细菌基因组学研究进展

粘细菌(Myxobacteria)隶属于δ变形菌纲(Deltaproteobacteria)的粘球菌目(Myxococcales),是一类革兰氏阴性杆状细菌。它是继放线菌和真菌之后又一重要的活性次级代谢产物产生菌,尽管如此,由于分离纯化困难,粘细菌的研究进展一直较为缓慢。随着测序技术的进步和生物信息学的应用,大量粘细菌基因组被完成测序和报道。本文对粘细菌研究意义及该类资源开发价值、分离培养存在的困难进行了阐述,对粘细菌基因组注释及目前已测菌株的全基因组进行了归纳总结,同时介绍了基因组学在粘细菌生态、捕食机制、子实体形成以及次级代谢产物合成方面的研究进展。本文有助于了解基因组学在粘细菌研究中的重要价值,为联合应用多组学技术深入研究粘细菌代谢机制和社会性行为提供了参考,对粘细菌基础研究、资源发掘和开发利用具有重要意义。     

纤维堆囊菌的供谢产物及其生物学活性分析

纤维堆囊菌不同菌株不但表现细胞和子实体形态的差异,而且供谢产物的组成和生物学活性也存在差异。纤维堆囊菌对革兰氏阴性细菌不表现任何抑制活性,部分菌株可抑制革兰氏阳性细菌;但所有菌株对真菌和肿瘤细胞有广泛和强烈的抑制作用。薄层层析显示,纤维堆囊菌的次级代谢产物组分较多,且大多数组分具有不同程度的抑制真菌和肿细胞的活性。在筛选中发现四株菌的代谢产物能够促进微管蛋白聚合,其中So33-1活性组分的薄层层析Rf值与已知的Epothilone A相似,而So81的则有较大的差异。研究结果表明纤维堆囊菌是很好的筛选抗真核生物活性的天然化合物资源。     

粘细菌次生代谢产物中大环类化合物的研究进展

粘细菌可以产生多种次生代谢产物,是继放线菌、芽胞杆菌之后的第3大类次级代谢产物产生菌。本文综述了粘细菌次生代谢产物中大环类化合物的研究进展。首先介绍了粘细菌中分离的主要大环类化合物种类、结构特征及来源菌株;然后分别从抗肿瘤、抗菌、抗病毒等几方面对其生物活性进行概述;最后对粘细菌次生代谢产物中大环类化合物的相关研究工作进行了展望。     

粘细菌:一类重要的微生物资源

粘细菌 (Myxobacteria)是革兰氏阴性单细胞杆状细菌 ,具有有独特的生活史 ,在细胞分化发育和生物进化研究中占有重要地位。尤为重要的是粘细菌可产生丰富的次级代谢产物 ,是一类具有重要经济价值的微生物资源。本文简单地介绍了粘细菌生物学特性、分离纯化、系统分类、活性物质的研究 ,以推动粘细菌资源的全面研究、开发和利用。     

黏细菌:天然的制药厂

黏细菌及其抗性代谢产物的药用开发已经成为近年来科研工作者研究的热点之一。黏细菌是一类重要的天然产物生产者,它产生的次级代谢产物无论是在化学结构还是生物活性上都具有丰富的多样性。代谢产物的多样性及广谱活性,在开发成药物方面具有巨大的潜力。主要综述了黏细菌独特的细胞行为,产生次级代谢产物的杰出能力,并且阐述了黏细菌药物埃博霉素的研发进展,最后对黏细菌次级代谢产物开发应用潜力进行了展望。     

粘细菌生物活性产物及其应用研究进展

粘细菌(myxobacteria)是一类具有多细胞群体行为特征的药源微生物类群。粘细菌能通过次级代谢产生大量结构新颖并具有生物活性的小分子天然产物,还能分泌种类、功能丰富多样的酶类。这些生物活性产物使粘细菌不仅具有重要的研究价值,还有广泛的应用前景。然而,资源挖掘困难、次级代谢产物得率低等制约因素的存在严重阻碍了粘细菌的研究和应用。本文主要对粘细菌的生物学特征、生物活性产物、生物合成调控及在医疗、农业和食品上的应用进行归纳总结,并结合已有成果对粘细菌研究存在的问题提出可能的对策和展望,为今后粘细菌的深入研究和资源开发利用提供参考。     

Characteristics of the membranes of the pellicle of the ciliatePseudomicrothorax dubius

Summary The membranes of the pellicle of the ciliatePseudomicrothorax dubius are investigated using thin section electron microscopy and freeze-fracture replicas. The plasma membrane is covered by a surface coat and is connected to the outer alveolar membrane by short, sometimes branched, bridges. The inner alveolar membrane is coated on both sides. The epiplasm lies in intimate contact with the cytoplasmic surface of this membrane, and there is a corresponding deposit on the other surface. This deposit is regularly striated.The epiplasmic layer and the alveoli are interrupted at sites of cytotic activity,e.g., the attachment sites of trichocysts, the cytoproct, and the parasomal sacs. The striated deposit ends where the epiplasm ends, indicating a direct relationship between these two epimembranous layers.There is a deposit along the sides of the first part of the tip of the trichocysts, and in this region the trichocyst membrane is free of intramembranous particles.The membrane of the parasomal sacs has a coat on both surfaces. That on the extraplasmic surface is similar to the surface coat of the plasma membrane. The origin of the cytoplasmic coat is unknown. The cytotic activity of these sacs is indicated by their highly irregular profiles.     

The early development of the tail and the transformation of the shape of the nucleus of the spermatid of the domestic fowl,Gallus gallus

Summary The differentiation of the spermatid, especially in reference to the formation of the flagellum, and transformation of the shape of the nucleus was investigated in the domestic fowl.In the early stage of the spermatid, a prominent Golgi apparatus appears around the centrioles. The Golgi vesicles then surround the axial-filament complex which develops from the distal centriole. These vesicles fuse to form continuous membrane at the earliest stage of flagellar formation, and in the succeeding stage Golgi lamellae are attached to the plasma membrane of the developing flagellum. From these observations, it is assumed that Golgi apparatus may be a source of the membrane system of the flagellum.The microtubules distributed around the nucleus form the circular manchette. The anterior region of the nucleus with the manchette is cylindrical in shape and the posterior region without it remains irregular in shape. When the circular manchette has been completed, the whole nucleus acquires a slender cylindrical shape. The circular manchette then changes into the longitudinal manchette. The nuclei of spermatids without a longitudinal manchette are abnormal in shape. In view of these observations it is assumed that the nuclear shaping of the spermatid may be accomplished by circular manchette and the maintenance of shape of the elongated nucleus by longitudinal manchette.The authors wish to thank Mr. Takayuki Mori for his helpful suggestions and technical advices     

Characterization of the composition of the aqueous humor and the vitreous body of the eye of the frog Rana temporaria L

This study aimed to analyze the aqueous humor (AH) and the vitreous body (VB) of the eye of the adult frog Rana temporaria L. as a representative species of amphibians, which lead a semi-terrestrial life. The presence of collagen, albumin, uric acid and electron donors was shown in both media; however, there are slight differences in their concentrations. To determine collagen, a spectral-fluorescent probe, cyanine dye, was used. The presence of collagen in AH of the frog was found at the first time. The total content of electron donors (ascorbic and uric acids, tryptophan, and tyrosine) in VB and HA was roughly estimated at ~ 1.5 × 10^− 4 mol/L. Both VB and AH absorb light in similar UV regions. The total protein and albumin contents in AH were found to be somewhat higher than those in VB. The uric acid content was at an equally low level in both intraocular media. It is supposed that the similarity of VB and AH compositions shown in this work is due to some exchange between VB and AH contents in the course of accommodation. The role of intraocular fluids in physiological functions of the eye and in protecting the retina against UV light is discussed.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418