亚麻枯萎病菌生长和产毒最适培养条件初探

由尖孢镰刀菌亚麻专化型[Fusarium oxysporum Schl.f.sp.lini(Bolley)]引起的亚麻枯萎病是我国亚麻主产区重要的真菌病害之一。本文对尖孢镰刀菌亚麻专化性病菌的生长和产毒条件进行研究,结果表明:病菌在6种不同培养液中均能生长和产毒,其中MS无机盐+蔗糖培养液最利于菌丝生长,Armstrong镰刀菌培养液最利于孢子生长,Richard培养液最适合产毒。病菌最适生长培养条件为25℃、24小时连续黑暗、PH值为7、25~30天;病菌产毒最适培养条件为30℃、24小时连续光照、PH值为7、培养30天。     

培养基营养成分对香蕉枯萎病尖孢镰刀菌生长的影响

通过对香蕉枯萎病发病株病组织的分离、纯化,得到香蕉枯萎病病原菌--尖镰孢菌古巴专化型[Fusarium oxysporum f.sp.cubense(E.F.Smith)Snyder et Hansen].该病原菌在不同pH值培养基上培养4 d后,发现尖孢镰刀菌菌落在pH值4.0～9.0范围内均可生长,pH值为6.0～7.0时最适,菌落直径平均在3.7～3.9 cm之间.尖孢镰刀菌在不例营养成分的培养基上培养,结果表明,N源对尖孢镰刀菌菌丝的生长影响大于C源.生长到第6天时,全糖型培养基产孢量最大,且小型分生孢子的产孢量也最大,可使香蕉苗发病率达到100%.而大型分生孢子的产生最佳培养基为低氮型培养基.     

向日葵枯萎病菌的分离鉴定及其生物学特性

为明确向日葵枯萎病的病原菌种类,调查来自不同地区2014-2015年田间向日葵枯萎病株(50份),经过柯赫氏法则鉴定,将分离获得的31株分离物鉴定为镰刀属下的7个不同的种,即尖孢镰刀菌(F.oxysporum)、轮枝镰刀菌(F.verticilloides)、砖红镰刀菌(F.lateritium)、锐顶镰刀菌(F.acuminatum)、芬芳镰刀菌(F.redolens)、木贼镰刀菌(F.equiseti)和层出镰刀菌(F.proliferum)。以每个种随机选取的菌株为研究对象,对其生物学特性进行了比较研究。结果表明:轮枝镰刀菌BC012的生长速度最快,而砖红镰刀菌BC03生长速度最慢;产孢量以轮枝镰刀菌BC012最多,而木贼镰刀菌NMG1的产孢量最少。在不同的培养温度下,除锐顶镰刀菌TBB212可在5℃低温下生长外,其余菌株的最适生长温度均为25℃~30℃。所有供试的菌株在p H 4~11的培养条件下均可生长。不同种的镰刀菌株产毒能力的比较结果表明,尖孢镰刀菌BC102的产毒能力最强,粗毒素含量为0.651 mg/m L;砖红镰刀菌BC03的产毒能力最弱,粗毒素含量仅为0.075 6mg/m L。不同种的镰刀菌的致病力测定结果表明,接种21d后,轮枝镰刀BC012、芬芳镰刀菌WLJ1和锐顶镰刀菌TBB212的病情指数分别为65.0、55.0、55.0,症状表现为侵染快、发病早、病叶边缘变黄变褐且叶面上出现斑驳状病斑;木贼镰刀菌NMG1、层出镰刀菌T5、尖孢镰刀菌BC102和砖红镰刀菌BC03病情指数在30.0至40.0;症状表现为发病较晚,病叶少且症状轻。而对照菌株向日葵黄萎病菌株大丽轮枝菌的病情指数仅为25.0。     

火龙果镰刀菌果腐病病原菌鉴定及生物学特性研究

采用形态学特征观察、rDNA-ITS序列、EF-1α序列比对和系统发育树分析的方法对引起火龙果镰刀菌果腐病病原菌进行鉴定,并初步研究其生物学特性。结果表明:引起火龙果镰刀菌果腐病是单隔镰刀菌(Fusarium dimerum Penzig in Saccardo),这是该菌引起火龙果果腐病在国内的首次报道。该菌菌丝生长的适宜温度25~35℃,最适温度30℃,适宜产孢温度25~35℃,最适产孢温度30~35℃,致死温度75℃(10 min);适宜pH5~9,最适pH7,最适产孢pH4;连续光照、D-果糖为碳源、牛肉膏和蛋白胨为氮源时最有利于该菌菌丝生长;完全黑暗、D-半乳糖为碳源、尿素为氮源时最有利于该菌产孢。综合分析认为,该菌耐高温,光照充足、弱酸和富含有机营养的环境有利于该菌的生长和繁殖。     

辽宁省玉米穗腐病致病层出镰孢菌生物学特性、致病力与产伏马毒素B1比较

层出镰孢菌Fusarium proliferatum是辽宁省玉米穗腐病致病镰孢菌之一。比较4株层出镰孢菌的生物学特性、致病力、伏马毒素生物合成基因的表达量和产伏马毒素能力。结果表明,供试层出镰孢菌适宜生长温度为25℃～30℃,Fp-2、Fp-3、Fp-6最适温度为25℃,Fp-7最适温度为28℃。适宜pH值为5～8,Fp-2、Fp-7的最适pH值为7;Fp-3耐碱性,最适pH值为8;Fp-6耐酸性,最适pH值为5。12 h光暗交替有利于菌丝生长,适宜生长培养基为PSA、PDA。不同菌株对碳氮源的利用存在差异,适宜碳源为可溶性淀粉和蔗糖,适宜氮源为亚硝酸钠、天冬氨酸和脯氨酸。4株层出镰孢菌均能产生毒素,菌株间产毒能力差异显著,菌株Fp-7产伏马毒素B1能力最强,为77.65 mg/kg。菌株间产毒基因的相对表达量也存在差异,致病力无明显差异。     

尖孢镰刀菌西瓜专化型菌株的生物学特性

通过对尖孢镰刀菌西瓜专化型菌株[Fusariumoxysporumf.sp.niveum(E.F.Smith)SnyderetHansen.]在不同培养基、不同温度、不同光照及不同的pH梯度条件下的生长速度、产孢情况等的对比,以及菌落、孢子形态特征观察,筛选出PDA、26℃、全日光照和pH7￣11为镰刀菌菌株生长和产孢最佳的培养基、温度和光照条件。并通过该菌株对几种杀菌剂的敏感性测验,发现丙环唑、烯唑醇、百菌清、代森锌4种生产常用杀菌剂对菌株的毒力具有显著差异,其中烯唑醇对该菌株的毒力最强。     

野茼蒿链格孢YTH-21菌株的生物学特性及致病性研究

对野茼蒿(Alternaria sp.)YTH-21菌株的生物学特性及致病性进行研究,结果表明:该菌的菌丝体生长速度快,致病性强;菌丝体生长最适温度为25℃,产孢及孢子萌发最适宜温度均为30℃,致死温度为50℃、10min;菌丝体生长和产孢适宜pH值范围为5.0～8.0,最适宜于孢子萌发的pH值为7.0;对菌丝体生长及产孢最好的碳源为葡萄糖,但不利于孢子萌发;供试氮源以氯化铵对菌丝体生长及产孢表现出明显的抑制作用.     

玉米黄斑病菌产毒条件及毒素稳定性研究

玉米黄斑菌(Curvularia lunata)是一具有产毒作用的半知菌。通过试验表明,不同的培养条件菌丝体的产毒量不同,产毒以15～20 d达到高峰,产毒的适宜pH值为6,适宜温度15～20℃,并且黑暗和静止条件相对于光照和振荡条件产生毒素量较多;玉米黄斑菌毒素对热稳定,在黑暗条件下利于毒素保存。     

玉米穗腐病样本中温和镰孢菌的鉴定及其生物学特性

为明确引起玉米穗腐病的一种不常见镰孢菌病原菌及其生物学特性,对采集的镰孢菌穗腐病样本进行病原菌分离和纯化,并通过柯赫氏法则（Koch''s Rule）、形态学特征和分子生物学技术对菌株进行鉴定。结果表明,分离到的菌株ZBSF002为温和镰孢菌（Fusarium temperatum）,是玉米穗腐病的致病菌。对其生物学特性研究表明,温和镰孢菌的最适碳源是可溶性淀粉,最适氮源是酵母浸粉,生长温度范围为10℃~35℃,最适温度为30℃。在pH值为4~11的培养基上均能生长和产孢,在pH值7~10培养基上菌丝生长较快且产孢量较大。光照对菌丝生长和产孢量影响不显著,菌株在光照、黑暗、交替光照3种培养条件下均能生长和产孢,连续光照条件下菌丝生长较快,且产孢量较大。病原菌菌丝和分生孢子致死温度为65℃、10 min。     

油菜黑胫病菌（Leptosphaeria biglobosa）生物学特性研究

为了解我国油菜黑胫病病原菌（Leptosphaeria biglobosa）的生物学特性,在实验室里研究了温度、pH值、光照、碳源及氮源等条件对该病菌营养生长及分生孢子产生的影响。结果表明：病原菌在5℃～35℃均可进行营养生长并产孢,最适生长和产孢温度为25℃;在pH4～10的范围内该菌均能生长并产孢,在pH7的条件下生长最快,产孢最多。光暗交替有利于菌丝生长和产孢,而持续光照不利于菌丝生长,尤其不利于产孢。最适的碳源、氮源分别是可溶性淀粉、牛肉膏。分生孢子的致死温度为52℃。     

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.     

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.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).