抗生素菌种选育的研究进展

传统的诱变育种仍是目前抗生素菌种选育中最常用的育种技术,根据抗生素生物合成和代谢调控机制设计的育种方法——推理选育,可大大减少随机筛选的盲目性,提高筛选效率。原生质体融合技术和基因工程技术也被用于抗生素的菌种选育,以基因工程技术为主的多元化的育种方式是今后抗生素菌种选育的主导方向。     

辽宁省微生物科学研究院食用菌研究室简介

研究方向1．食用菌优良菌种选育2．食用菌液体菌种深层发酵技术研究3．食用菌病虫害防治技术研究主要研究内容1．杂交育种技术研究：通过食用菌孢子杂交,进行食用菌菌种选育。2．细胞融合技术研究：通过食用菌原生质体的制备融合及再生条件的研究,选育食用菌新品种。3．食用菌液体菌种深层发酵技术研究：进行食用菌液体菌种深层发酵条件及发酵工艺的研究。     

农用抗生素产生菌菌种选育的研究进展

农用抗生素产生菌的原始菌株 ,往往产量很低或质量较差 ,不能满足工业生产的需要 ,必须对它的某些性状进行改良。改良菌种的主要手段是通过育种 ,筛选出高产菌株。传统的诱变育种是最广泛的选育方法 ,以基因工程为核心的现代生物技术也应用于农用抗生素产生菌的菌种选育中 ,并逐渐成为农用抗生素菌种选育的主导技术。     

一种产生纤维素酶菌种的筛选方法——染色滤纸条法

目前选育产纤维素酶菌种,一般初筛用滤纸溃烂法选取生长旺、使滤纸溃烂显著的菌株,作为初筛结果。复筛时制曲、萃酶、过滤、离心及活性测定等步骤,工作量大,效率低,影响菌种选育工作的进展。我们在选育纤维素酶菌种中,对国外新近介绍的染色滤纸条法稍作改进,对数百株真菌作了初筛和初步复筛,证明用染色滤纸条法,可减少工作量,并能以数百株菌同时投入初筛,提高了筛选效率,加速了菌种的选育过程。现将方法介绍如下。     

有关微生物菌种选育技术的探索

所谓微生物菌种选育技术指的是,有机运用以遗传学为代表的相关原理,对目标微生物菌种展开相应筛选及其改造,从而达成所需产物大幅增产的一门技术。鉴于此,本文首先对传统微生物菌种选育技术进行了简要介绍,然后针对基因组改组技术进行了重点讨论和研究,以便同行参考。     

辽宁省微生物科学研究院食用菌研究室简介

研究方向 1．食用菌优良菌种选育 2．食用菌液体菌种深层发酵技术研究 3．食用菌病虫害防治技术研究     

植酸酶的研究与应用进展

综述了植酸酶的生物学特性 ,产植酸酶的菌种来源 ,以及通过诱变和基因工程对菌种的选育 ,并阐述了植酸酶在饲料中的应用     

利用紫外诱变选育辅酶q10菌种的研究

微生物育种指的是运用遗传学、诱变、杂交等原理,对负有特定作用的微生物菌种开展筛选、改造,从而得到符合某种需要的技术。本文对微生物菌种选育技术中的紫外诱变来选育辅酶q10高产菌株进行了一系列的试验和研究。。     

辽宁省微生物菌种保藏中心

简介辽宁省微生物菌种保藏中心是2005年经辽宁省科技厅批准、依托辽宁省微生物科学研究院组建的东北三省唯一的微生物菌种专业保藏管理机构:主要从事微生物菌种资源分离、收集、鉴定、评价,优良菌种选育、保藏、供应及对外交流开展微生物菌种保藏与应用技术研究。     

辽宁省微生物菌种保藏中心

正辽宁省微生物菌种保藏中心是200年经辽宁省科技厅批准、依托辽宁省微生物科学研究院组建的东北三省唯一的微生物菌种专业保藏管理机构,主要从事微生物菌种资源分离、收集、鉴定、评价,优良菌种选育、保藏、供应及对外交流,开展微生物菌种保藏与应用技术研究。     

Biological Control of Thrips on Ornamental Crops: Interactions Between the Predatory Mite Neoseiulus cucumeris (Acari: Phytoseiidae) and Western Flower Thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), on Cyclamen

Difficulties in controlling outbreaks of Western flower thrips, Frankliniella occidentalis, have obstructed the widespread adoption of biological control in many ornamental crops. The efficacy of the predatory mite, Neoseiulus cucumeris, in controlling F. occidentalis on two cultivars of cyclamen was tested in glasshouse experiments. The establishment and development of F. occidentalis populations was compared in three treatment introductions of N. cucumeris (50, 200 and 350 mites m -2 per week) and an untreated control. F. occidentalis were sampled in the flowers over eight weeks and counted into different life stages. No differences were observed between the two cultivars. All treatments with the predator resulted in a decline in numbers of F. occidentalis compared to the untreated control. Although the proportion of first instar F. occidentalis was similar in all treatments, the level of control varied with the number of N. cucumeris introduced. Lower populations of F. occidentalis, combined with a more rapid decline in their numbers, were observed at the 200 and 350 mites m -2 rates. Numbers of F. occidentalis remained low in the 350 N. cucumeris m -2 rate and the proportion of second instar F. occidentalis in the samples was consistently lower than in the other treatments. Trap counts of adult F. occidentalis were strongly correlated with the numbers of both adult and total F. occidentalis in flower samples. High inoculative releases of N. cucumeris early in the flowering cycle followed by frequent low introductions of predators should provide a strong basis for preventative control of F. occidentalis and other thrips species on cyclamen.     

Screening Isolates of Hirsutella Species for Biocontrol of Heterodera glycines

The fungi, Hirsutella rhossiliensis and Hirsutella minnesotensis, are two endoparasites of second-stage juveniles (J2) of the soybean cyst nematode (SCN), Heterodera glycines. The objective of this study was to screen for effective fungal isolates to control the nematode in laboratory and greenhouse assays. A total of 93 isolates of H. rhossiliensis and 25 isolates of H. minnesotensis were evaluated for parasitism of SCN J2 on cornmeal agar. Percentage of SCN J2 parasitized by the fungi varied among the fungal isolates. Most H. rhossiliensis isolates parasitized a high percentage of J2. The isolates of H. rhossiliensis obtained from bacteria-feeding nematodes, however, generally did not parasitize J2 on agar. H. minnesotensis parasitized fewer J2 on agar than did H. rhossiliensis . Forty isolates of H. rhossiliensis and four isolates of H. minnesotensis that parasitized a high percentage of J2 on agar were evaluated for their biocontrol potential in soil treated with microwave heating. Most isolates selected from the agar assay also parasitized a high percentage of J2 in the soil but there was variation among isolates. Pathogenicity of 14 isolates of H. rhossiliensis and four isolates of H. minnesotensis to the SCN was also investigated in the greenhouse using untreated field soil. Most isolates of H. rhossiliensis reduced SCN population density and increased plant growth when compared with 1% corn-grits control (culture media). One isolate (OWVT-1) of H. rhossiliensis reduced the SCN egg density by 95% and J2 density by 98% when compared with the control. Isolates of H. minnesotensis, however, neither reduced SCN density nor increased plant growth in the greenhouse.     

Comparison of in vitro decomposition of bryophytic and tracheophytic plant material

The fossil record of bryophytes is generally poor and infertile plants attributable to liverworts and mosses could also be thalloid vascular plant gametophytes or herbaceous lycophytes respectively. The paucity of the bryophytic record could be the result of relatively rapid degradation of bryophytic material in comparison to that of vascular plants, the absence of lignified cells in bryophytes sustaining this belief. However, certain organs of bryophytes are as robust as those of vascular plants (e.g. spores) and the hydroxybenzofuran polymers produced by some mosses could be of similar preservational resistance to lignins. A simplistic experiment to test the relative resistance to decay of bryophytic material has been undertaken. Its findings suggest that bryophytic plant material has a similar preservational potential to that of a selected vascular plant, particularly in organic rich sediments. This result may be construed to imply that bryophytes were indeed less abundant in the preservational environments of the Coal Measures than might be expected on the basis of current palaeoenvironmental reconstructions.     

Effect of Herbivore Density, Timing of Attack and Plant Community on Performance of Creeping Thistle Cirsium arvense (L.) Scop. (Asteraceae)

Creeping thistle, Cirsium arvense (L.) Scop. (Asteraceae), is one of the most serious weeds in ecological compensation areas (within-field or border refugia) in Europe. Since conventional weed control measures are restricted in compensation areas, augmenting indigenous agents for biological control of the weed may be a feasible alternative. In this paper, we studied the effect of density of the shield beetle, Cassida rubiginosa Muller (Coleoptera, Chrysomelidae), and two vegetation types typical for ecological compensation areas, on the performance of creeping thistle plants in an open field experiment. Early-season larval feeding had no measurable effect on creeping thistle growth, while late-season feeding significantly reduced shoot growth. These findings were attributed to higher feeding rates of the herbivores at higher ambient temperatures late in the season. Defoliation had a strong effect on the above-ground performance of C. arvense plants, but not on the below-ground performance. In contrast, the plant community affected all below-ground performance parameters measured, but only some of the above-ground performance parameters of creeping thistle. A combination of high levels of plant competition and herbivory by C. rubiginosa larvae led to 50% mortality in C. arvense plants during the growing season. We conclude that augmentation of indigenous herbivores of C. arvense in combination with breaking up the root system by tillage and the establishment of a highly competitive plant community of beneficial herbs may be a feasible way to control this problematic weed in ecological compensation areas.     

Explanation and prediction in vegetation science

A definition of vegetation science is given, spanning 6 levels of integration and stressing the interrelations among them. The problems of realism are discussed. The selection of levels is related to the adequate correspondence between conceptualization and research aims. Pattern and process are introduced as the central concepts of vegetation science. The perception of reality is dependent on the spatial and temporal scale chosen. The concept of noise is discussed in relation to stochasticity and randomness of events. Traces of essentialism are found both in classification of communities and habitat ecology. Classification is important, particularly the coexistence of alternative classification approaches. Organicism as a basis of vegetation research is rejected because the organismic view is inadequate on higher integration levels. The concept of function is redefined in a non-teleologic way.Present vegetation ecological research is inductivistic. One possible alternative to inductivism is falsificationism. The major domain of this approach is hypothesis testing, which will become more important. Progress can only be reached by a maximum degree of communication among scientific individuals.Predictive ecology is partly based on historic explanation, partly on complementary approaches. Characters of vegetation worthwhile to be predicted are listed and the necessary requirements for vegetation science to become predictive are discussed. A major requirement is the development of succession and life-history theory. A further elaboration of the individualistic concept will be a main task of vegetation science in the near future.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

Growth stimulation of Treponema denticola by periodontal microorganisms

Previous experiments have indicated that enrichment of subgingival plaque in human serum can lead to the accumulation of Treponema denticola. T. denticola depends on bacterial interactions for its growth in serum. Aim of the present study was to identify specific microorganisms involved in the growth stimulation of T. denticola. To this end, strains isolated from previous plaque enrichment cultures were tested for growth stimulation in co-cultures with T. denticola. In addition, growth of T. denticola was tested in culture filtrates of the same strains, Bacteroides intermedius, Eubacterium nodatum, Veillonella parvula and Fusobacterium nucleatum were found to enhance growth of T. denticola in co-cultures. A continuous co-culture of T. denticola, F. nucleatum and B. intermedius in human serum gave very high levels of T. denticola, up to 3.10(9).ml-1. Mechanisms involved in growth stimulation may include the ability of B. intermedius and E. nodatum to cleave the protein-core of serum (glyco-)proteins, making these molecules accessible for degradation by T. denticola. In addition, E. nodatum was found to produce a low-molecular weight growth-factor for T. denticola, that was heat-stable and acid as well as alkaline resistant. V. parvula may provide peptidase activities complementary to those of T. denticola. The nature of the growth enhancing activity of F. nucleatum is yet unknown. The data support the dependency of T. denticola on other bacterial species for growth in the periodontal pocket.     

Some observations on the swimming and feeding of the nauplius larvae of Lepas pectinata (Girripedia: Crustacea)

Limb movements of restrained stage VI nauplii of Lepas pectinata were studied by cine-photography. Outline drawings were made of successive limb positions in both swimming and grooming activity. The antennae appeared to act as leaky paddles performing both propulsion and food gathering. Free-swimming nauplii averaged 120 limb beats min^-1 and a speed of c. 4 mm s^-1. Grooming occurred every 7–20 beats.
It was concluded that lack of streamlining favours filtration at the expense of propulsion. The grooming sequence differs from that of balanid nauplii and is one method of transferring food to the vicinity of the mouth, where sorting and rejection take place prior to ingestion. Fine- and coarse-mesh filters presumably exploit different plankton types. The overall behaviour pattern is well-designed for exploitation of scarce food in the oligotrophic conditions of the ocean-surface habitat.     

Cytochemical and molecular characteristics of the process of cornification during feather morphogenesis

Feathers are the most complex epidermal derivatives among vertebrates. The present review deals with the origin of feathers from archosaurian reptiles, the cellular and molecular aspects of feather morphogenesis, and focus on the synthesis of keratins and associated proteins. Feathers consist of different proteins among which exists a specialized group of small proteins called beta-keratins. Genes encoding these proteins in the chick genome are distributed in different chromosomes, and most genes encode for feather keratins. The latter are here recognized as proteins associated with the keratins of intermediate filaments, and functionally correspond to keratin-associated proteins of hairs, nails and horns in mammals. These small proteins possess unique properties, including resistance and scarce elasticity, and were inherited and modified in feathers from ancestral proteins present in the scales of archosaurian progenitors of birds. The proteins share a common structural motif, the core box, which was present in the proteins of the reptilian ancestors of birds. The core box allows the formation of filaments with a different molecular mechanism of polymerization from that of alpha-keratins. Feathers evolved after the establishment of a special morphogenetic mechanism gave rise to barb ridges. During development, the epidermal layers of feathers fold to produce barb ridges that produce the ramified structure of feathers. Among barb ridge cells, those of barb and barbules initially accumulate small amounts of alpha-keratins that are rapidly replaced by a small protein indicated as “feather keratin”. This 10 kDa protein becomes the predominant form of corneous material of feathers. The main characteristics of feather keratins, their gene organization and biosynthesis are similar to those of their reptilian ancestors. Feather keratins allow elongation of feather cells among supportive cells that later degenerate and leave the ramified microstructure of barbs. In downfeathers, barbs are initially independent and form plumulaceous feathers that rest inside a follicle. Stem cells remain in the follicle and are responsible for the regeneration of pennaceous feathers. New barb ridges are produced and they merge to produce a rachis and a flat vane. The modulation of the growth pattern of barb ridges and their fusion into a rachis give rise to a broad variety of feather types, including asymmetric feathers for flight. Feather morphogenesis suggests possible stages for feather evolution and diversification from hair-like outgrowths of the skin found in fossils of pro-avian archosaurians.     

Developing Methods for Testing Host Specificity of Phymastichus coffea LaSalle (Hym.: Tetrastichinae), a Potential Biological Control Agent of Hypothenemus hampei (Ferrari) (Col.: Scolytidae) in Colombia

In line with the United Nations Food and Agriculture Organization Code of Conduct for the import and release of biological control agents, and taking into consideration the recommendations in the draft IUCN (International Union for Conservation of Nature and Natural Resources) Guidelines for the Prevention of Biodiversity Loss Due to Biological Invasion, a procedure was developed to assess the host range of Phymastichus coffea , an endoparasitoid of coffee berry borer, Hypothenemus hampei . Host specificity was tested by exposing a Kenyan biotype of P. coffea to a selection of Scolytidae under quarantine conditions. The results demonstrated that P. coffea can be considered as oligophagous, attacking and developing on other species of the genus of the target borer. In no-choice tests, three species, H. obscurus , H. seriatus and Araptus sp. yielded parasitism. The risk of attack to potential alternative hosts if P. coffea were to be released as a potential biological control agent of coffee berry borer in Colombia is discussed. A quarantine procedure was developed for the importation of P. coffea to Colombia to deal with specific problems of hyperparasitoids and fungal contamination.