壳聚糖酶产生菌Strptomyces clavuligerus sp.P1选育研究

【目的】选育壳聚糖酶高产菌株.【方法】利用段杉建立的筛选模型,对螃蟹养殖地附近土样进行筛选。通过形态学、生理生化及16S rDNA序列测定,对菌株进行分类鉴定。【结果】鉴定该菌株为Streptomyces clavuligerus属的一个种,定名为：Strptomyces clavuligerus sp.P1,最大酶活力0．443U／mL。[结论】该壳聚糖酶产生菌的获得可为开发壳聚糖酶制剂奠定基础。     

枯草芽孢杆菌(Bacillus subtilis)CS27液体发酵条件优化

从提高细胞生物量并降低发酵生产成本的目的出发,本文采用单因素试验和正交试验方法,对已筛选出的枯草芽孢杆菌CS27菌株进行液体发酵培养基和工艺条件优化。得到最佳培养基配方为:1.5%黄豆粉、0.5%糖蜜、0.8%氯化铵、1.0%氯化钠、0.1%柠檬酸钠、0.5%碳酸钙、0.1%七水合硫酸镁;最佳发酵条件为:发酵温度32℃,最佳装液量50 mL/250 mL,最适接种量10%,初始pH7.0。在优化后的培养基发酵条件下细胞生物量可以达到1.75×10~9 cfu/mL,为枯草芽孢杆菌CS27菌株规模化生产及应用提供科学依据。     

解淀粉芽孢杆菌TWC2发酵条件的优化

为了提高解淀粉芽孢杆菌Bacillus amyloliquefaciens TWC2菌株活性代谢物质的产量,以菌体生物量和发酵液拮抗甘蔗赤腐病菌(Colletotrichum falcatum Went.)活性为指标,采用单因素和正交试验的方法对TWC2菌株发酵培养基成分和发酵条件进行优化。结果表明,TWC2菌株最佳发酵培养基组成为:5 g/L麦芽糖,10 g/L果糖,10 g/L蛋白胨,10 g/L酵母浸出粉,1 g/L CaCl_2。最适发酵条件为:培养温度34℃,摇床转速200 r/min,发酵起始pH 6.0~6.5,接种量7%,装液量40 mL/250 mL,发酵时间为48 h。在最佳发酵培养基和培养条件下,发酵液抑制甘蔗赤腐病菌的能力较优化前提高了39.91%。     

真姬菇在藜麦固体培养基上发酵条件的探讨

[目的]探讨真姬菇在藜麦固体培养基上发酵条件.[方法]利用真姬菇菌丝体发酵藜麦,以多糖为目标产物,通过固体发酵单因素试验,对碳源,氮源,碳源、氮源添加量,含水量,时间等条件进行筛选.[结果]最适条件为:糊精作为碳源,酵母粉作为氮源,碳源、氮源添加量为5:1,含水量为80％,发酵时间为20 d.并测定发酵前后生理活性物质...     

米曲霉40214高产中性蛋白酶发酵条件的优化

运用现代生物学技术,对米曲霉40214菌株发酵产中性蛋白酶的培养基组分及培养条件进行优化,旨在提高菌株产中性蛋白酶的产量。通过单因素实验和正交实验确定了发酵培养基的最佳组分,添加葡萄糖8.0%,酵母粉4.0%,Na2HPO40.10%;最适发酵条件为发酵温度28℃,初始pH值6.5,发酵时间96 h,加水量60.0%,经过优化后酶活性提高了1.75倍,达到2 845.68 U/mL,实验为进一步提高米曲霉40214菌株产中性蛋白酶的能力并将其应用到食品发酵中奠定了理论基础。     

CXJZ11-01菌株分泌中性β-甘露聚糖酶的研究

对现有菌种资源进行提纯复壮和筛选,采用透明圈法和发酵液酶活力比较法,获得高产中性β-甘露聚糖酶菌株CXJZ11-01。进而采用单因子和多因子相结合的统计方法以及DNS法,对该菌株β-甘露聚糖酶活力检测体系及其产酶规律进行系统研究。结果表明:该中性β-甘露聚糖酶最适pH值为6.0,最适温度为65℃;菌株CXJZ11-01在适宜条件下培养9小时,发酵液粗酶活力高达3050U/ml。     

CXJZ11-01菌株分泌中性β-甘露聚糖酶的研究

对现有菌种资源进行提纯复壮和筛选，采用透明圈法和发酵液酶活力比较法，获得高产中性β-甘露聚糖酶菌株CXJZ11-01。进而采用单因子和多因子相结合的统计方法以及DNS法，对该菌株β-甘露聚糖酶活力检测体系及其产酶规律进行系统研究。结果表明：该中性β-甘露聚糖酶最适pH值为6．0，最适温度为65℃；菌株CXJZ11-01在适宜条件下培养9小时，发酵液粗酶活力高达3050U／ml。     

地衣芽孢杆菌发酵柞蚕丝胶蛋白生产丝胶肽工艺优化

[目的]柞蚕结茧产生的茧壳中的丝胶利用率不高,利用地衣芽孢杆菌降解丝胶蛋白,为解决丝胶废弃物再利用问题提供有效方法。[方法]以柞蚕茧壳为研究材料,利用地衣芽孢杆菌进行发酵,以辐射梯度、发酵天数、温度、转速等为因素,在单因素试验的基础上,以水解度为指标,通过组合试验设计对发酵条件进行优化,获得最佳发酵条件。[结果]最佳发酵条件为:辐射梯度15 k·gy、发酵天数5 d、摇床转速160 r/min。在该条件下,得到最大水解度为72.284%。[结论]该研究为柞蚕茧壳丝胶再利用提供了有效方法,为柞蚕茧壳生产丝胶肽提供了理论基础。     

人参内生菌B69菌株抑菌活性物质产生条件的优化

目的探索人参内生菌B69菌株对根腐病的抑制作用,优化人参病害拮抗菌株B69的发酵条件,提高发酵液的活菌含量和抗菌活性。方法以B69发酵液对病原菌根腐病的抑制作用为活性指标,采用正交试验和单因素试验方法对菌株的最适发酵培养基成分及发酵条件进行优化。结果在最佳发酵培养基和培养条件下,经检测发酵液的活菌数含量为8.25×108 cfu/m L,较优化前的活菌含量1.82×108cfu/m L增幅达到了显著差异(P0.05),此含量达到了农业部微生物肥料的技术标准(有效活菌数≥2.0亿/m L)。发酵液对人参根腐病的抑菌圈也由优化前的18mm增加到35mm。结论最佳培养基配方为蔗糖2.0%、淀粉1.0%、牛肉浸膏0.5%、酵母粉0.5%、蛋白胨0.2%和Na Cl0.5%;初始p H7.0;最适装液量为100 m L/250 m L;培养条件为35℃、170r/min振荡培养;接种量5%,发酵时间为48h。     

壳寡糖对黄瓜黑星病病菌抑制机理初探

[目的]研究酶降解法制备的壳寡糖对黄瓜黑星病病菌的抑制机理。【方法】测定壳寡糖对黄瓜黑星病菌菌丝发育、孢子萌发的抑制率,观察壳寡糖处理前后病菌菌丝形态及细胞膜透性变化。【结果】当壳寡糖处理浓度为0．2g／mL以上时,可完全抑制病菌菌丝生长;当处理浓度为O．1g／mL以上时,可完全抑制病菌孢子萌发。显微观察,浓度为O．8mg／m1．的壳寡糖处理可诱导菌丝分枝增多、菌体分隔增加,分生孢子形成受到抑制。此外壳寡糖能够引起菌丝细胞膜透性发生变化,造成菌丝体内含物的渗漏。【结论】该研究可为壳聚糖对黄瓜黑星病病菌的抑制提供参考依据。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.