Antigenic structure of saprophytic leptospirae and their classification]

The authors present the results of study of the serological properties of 46 strains of saprophytic leptospirae of different origin. On the basis of the affinity of the antigenic structure detected in the cross microagglutination reaction (MAR) 38 strains under study were united into 8 serological groups; the rest 8 strains were serologically independent in this reaction. The fact that 9 strains of water leptospirae isolated in the Armenian SSR belonged to one serological group was proved in the cross MAR and the test of aglutinin adsorption. This serological group was new and was named L. armenica. Five individual serological types of saprophytic leptospirae were differentiated in its composition. Comparative study of the serological interrelations between the group of strains isolated in Armenia and the strains of some serological groups and serological types the closest serological connections were noted in the K-1030 (serological group Armenica) and Bovedo (serological group Andamana) strains. It is believed that the existing division of the saprophytic leptospirae into two serological groups (Semaranga and Andamana) required widening and supplement by new serological groups and serological types.     

Staphylococci in Competition: II. Effect of Total Numbers and Proportion of Staphylococci in Mixed Cultures on Growth in Artificial Culture Medium

In studies carried on in bacteriological media with selected cultures, definite repressive effects were noted on the growth of the Staphylococcus population by a mixture of saprophytic, psychrophilic bacterial species. This repressive effect became more pronounced as the relative proportion of the bacterial population which was staphylococcal became smaller. A varied saprophytic bacterial flora of some numbers apparently would offer definite protection to foods through repression of staphylococcal growth and by rendering the food inedible before the rise of appreciable numbers of staphylococci. It would appear that at the optimal temperature for staphylococcal growth, staphylococci could multiply rapidly in the mixed population due to the comparative shortness of the generation time of this species and because of the lengthened lag phase of the saprophytic bacterial species at this elevated temperature, especially when only cultures having psychrophilic characteristics were present. This temperature is substantially above that encountered in practical experience. With the passage of time, the staphylococcal population was completely overgrown by the saprohytes present. This effect might be eliminated in the presence of psychrophilic and mesophilic, saprophytic species. The repressive effect of competition by saprophytic, psychrophilic organisms is extremely effective up to room temperature on the staphylococcal population. Even when significant staphylococcal populations were achieved in the artificial media, such tremendous numbers of saprophytes were obtained either earlier or at the same time so that a frozen food containing this population would be organoleptically unacceptable due to the degradative action of enzymes from the saprophytic psychrophile population.     

A COMPARATIVE STUDY OF OPHIOBOLUS GRAMINIS AND FUSARIUM CULMORUM IN SAPROPHYTIC COLONIZATION OF WHEAT STRAW

The competitive saprophytic ability of Ophiobolus graminis has been compared with that of Fusarium cultnorum. Test pieces of wheat straw were buried in maize-meal-sand inoculum mixed in various proportions with unsterilized soil, according to the technique already described by Butler (1953). Some possible sources of variation in the results obtained by this technique have been investigated. Saprophytic colonization of the straw tissues by Ophiobolus graminis appeared to decline as invasion progressed from the outer to the inner tissues, presumably owing to continued competition with other saprophytes. An experiment using as inoculum the stubble of plants naturally infected by O. graminis suggests that saprophytic colonization of wheat straw by the take-all fungus can occur only to a negligible extent in the field.     

Fitness of three Fusarium pathogens of wheat

Crown rot and head blight of wheat are caused by the same Fusarium species. To better understand their biology, this study has compared 30 isolates of the three dominant species using 13 pathogenic and saprophytic fitness measures including aggressiveness for the two diseases, saprophytic growth and fecundity and deoxynivalenol (DON) production from saprophytic colonization of grain and straw. Pathogenic fitness was generally linked to DON production in infected tissue. The superior crown rot fitness of Fusarium pseudograminearum was linked to high DON production in the stem base tissue, while Fusarium culmorum and Fusarium graminearum had superior head blight fitness with high DON production in grains. Within each species, some isolates had similar aggressiveness for both diseases but differed in DON production in infected tissue to indicate that more than one mechanism controlled aggressiveness. All three species produced more DON when infecting living host tissue compared with saprophytic colonization of grain or straw, but there were significant links between these saprophytic fitness components and aggressiveness. As necrotrophic pathogens spend a part of their life cycle on dead organic matter, saprophytic fitness is an important component of their overall fitness. Any management strategy must target weaknesses in both pathogenic fitness and saprophytic fitness.     

The ultrastructure of spores ofClaviceps purpurea (Fr.) Tul.

The ultrastructure of saprophytic and parasitic spores of the AscomyceteClaviceps purpurea (Fr.) Tul. was studied. Considerable differences were found to exist between the saprophytic and parasitic spores as to morphology and fine structure. The reason for the different ultrastructural morphology is probably connected with the intensity of cell metabolism. Whereas the parasitic spores obtained from the honeydew possess the character of a resting cell with a thick electron-dense cytoplasm, abundant lipid bodies, few mitochondria, an underdeveloped and hence little active endoplasmic reticulum and with a homogenous thick cell wall, the saprophytic spores appear as cells with higher metabolic rate, containing more numerous mitochondria, a thinner cytoplasm, a highly developed endoplasmic reticulum, fewer lipid bodies and abundant large vacuoles as well as frequently a new wall layer.     

Differentiation of Pathogenic and Saprophytic Leptospires I. Growth at Low Temperatures

The minimal growth temperature of the pathogenic leptospires is between 13 and 15 C. The saprophytic leptospires have a minimal growth temperature between 5 and 10 C, or approximately 5 C below that of the pathogens. The capability of the saprophytic leptospires to grow at temperatures below those which allow the growth of the pathogenic leptospires provides a simple method of discrimination. With an inoculum yielding approximately 8 x 10(7) cells per ml in the test medium and an incubation temperature of 13 C, the saprophytic leptospires were easily differentiated from the pathogenic leptospires. All 13 saprophytic leptospires tested grew in the 10% rabbit serum medium at 13 C, whereas none of the 20 pathogens grew during the 30-day incubation period.     

Toxigenic saprophytic fungi in marine shellfish farming areas

Toxigenic saprophytic fungi were isolated from samples of shellfish, sediment and seawater obtained from marine shellfish farming areas. The 456 strains identified included 12 different genera, with a clear predominance (68%) of Penicillium, Aspergillus, Trichoderma and Cladosporium. To assess the risk of poisoning due to the presence of these fungi in shellfish farming areas, the strains were cultured in liquid medium, filtered, and tested on larvae of Artemia salina, a small crustacean highly sensitive to mycotoxins. Thirty-five point five percent of the strains proved active with this test. This study confirms the existence of fungi in shellfish farming areas, as suggested by our earlier work showing that filter-feeding shellfish accumulate toxic metabolites of fungal origin. The presence of fungi in the marine environment represents a real risk of poisoning through the consumption of contaminated shellfish.This revised version was published online in October 2005 with corrections to the Cover Date.     

Origin, distribution and 3D-modeling of Gr-EXPB1, an expansin from the potato cyst nematode Globodera rostochiensis

Southern analysis showed that Gr-EXPB1, a functional expansin from the potato cyst nematode Globodera rostochiensis, is member of a multigene family, and EST data suggest expansins to be present in other plant parasitic nematodes as well. Homology modeling predicted that Gr-EXPB1 domain 1 (D1) has a flat beta-barrel structure with surface-exposed aromatic rings, whereas the 3D structure of Gr-EXPB1-D2 was remarkably similar to plant expansins. Gr-EXPB1 shows highest sequence similarity to two extracellular proteins from saprophytic soil-inhabiting Actinobacteria, and includes a bacterial type II carbohydrate-binding module. These results support the hypothesis that a number of pathogenicity factors of cyst nematodes is of procaryotic origin and were acquired by horizontal gene transfer.     

长白山森林生态系统腐木生苔藓植物生态分布的DCA排序研究

应用除趋势对应分析（ＤＣＡ）对长白山不同森林类型腐木生苔藓植物分布研究表明,长白山红松阔叶混交林、暗针叶林以及两者之间的过渡林林下腐木生苔藓植物组成明显不同．红松阔叶混交林以尖叶匍灯藓、毛尖羽藓、细枝青藓等为主;过渡林以尖叶匍灯藓、鞭枝疣灯藓、羽藓、腐木藓、塔藓等为主;暗针叶林的以塔藓、钩枝镰刀藓、拟垂枝藓、曲背藓、毛梳藓等为主．暗针叶林林下腐木生苔藓植物发生量最大,物种的多样性也最高．海拔高度和林冠郁闭度是影响长白山森林林下腐木生苔藓植物生态分布的主要因素．     

Interactions between Glomus mosseae and arbuscular mycorrhizal sporocarp-associated saprophytic fungi

The saprophytic fungi Wardomyces inflatus (Marchal) Hennebert, Paecilomyces farinosus (Holm & Gray) A. H. S. Brown & G. Sm., Gliocladium roseum Bain., sterile dark mycelium (SDM-54), Trichoderma pseudokoningii Rifai and Trichoderma harzianum Rifai were isolated from sporocarps of Glomus mosseae. The effect of saprophytic fungi on G. mosseae spore germination was tested on water agar. Wardomyces inflatus decreased the percent germination of G. mosseae spores; G. roseum, T. pseudokoningii and T. harzianum had no effect on germination; and P. farinosus and SDM-54 increased the percentage of spore germination of G. mosseae after 4 d. Wardomyces inflatus significantly decreased hyphal length of spores which germinated, but no other saprophytic fungi affected hyphal growth. Trichoderma pseudokoningii, T. harzianum, P. farinosus and SDM-54 increased the number of auxiliary cells formed by G. mosseae. The effect of saprophytic fungi on arbuscular mycorrhizal colonization of soybean was studied in a greenhouse trial. The percentage of soybean root length colonized was decreased by W. inflatus, unaffected by SDM-54 and T. harzianum, and increased by P. farinosus. Gliocladium roseum decreased root length colonized when plants were 12 wk old, and T. pseudokoningii increased colonization of roots when plants were 4 wk old. Antagonistic, synergistic and neutral actions of G. mosseae upon the saprophytic fungi were observed. The population of T. harzianum decreased and the populations of T. pseudokoningii and SDM-54 increased in the presence of G. mosseae. Our results indicate a complex interaction between G. mosseae and associated saprophytic fungi.     

山东半岛腐生小球腔菌属中国新记录种(英文)

在山东半岛腐生真菌调研过程中,鉴定出生于枯木上的4个小球腔菌属中国新记录种:光洁小球腔菌Leptosphaeriaagnita,灌丛小球腔菌L.dumetorum,嘴状小球腔菌L.eustomoides和茄小球腔菌L.solani。对各菌的形态学特征进行了描述、图解及讨论,并编制了中国小球腔菌属腐生种的检索表。研究标本保存在青岛农业大学菌物学实验室。     

Naphthylamidase Activity of Leptospira

Extracts of 18 serotypes of the genus Leptospira were found to possess naphthylamidase activity, and differences in the pathogenic and saprophytic strains were noted. The former exhibited a preference for the leucyl naphthylamide substrate, whereas the latter demonstrated greater hydrolysis of alanyl naphthylamide. With the leucyl naphthylamide as substrate, pathogenic strains showed 10 to 20 times higher naphthylamidase activity than saprophytic strains. Optimal temperature and pH for enzymatic hydrolysis also differed between pathogenic and saprophytic strains. Maximal enzymatic activities for pathogenic and saprophytic naphthylamidases were 41 and 37 C, respectively, at pH 8.0 to 8.5. The pH and temperature optima suggested that the leptospiral enzyme activity was not leucine aminopeptidase.     

Effects of inoculum density and substrate type on saprophytic survival of Phytophthora drechsleri, the causal agent of gummosis (crown and root rot) on pistachio in Rafsanjan, Iran

In this study, sampling was carrid out on soils around pistachio trees in various regions of Rafsanjan, Iran. Following isolation and identification of Phytophthora isolates, the predominant species was found to be P. drechsleri and used for further investigation. For studying saprophytic survival of the fungus, soils collected from different areas were combined and autoclaved. Sterile soil was divided into 10 parts and mixed with fungal inoculum at various concentrations of 0-9% (w/w) separately. Each soil part (100g) was placed in 15cm diameter plastic pot. Some soils in pots were supplemented with sterile wheat straw whereas others were mixed with pistachio leaves surface sterilized with 5% (v/v) sodium hypochlorite. After 3, 6 and 9 weeks of incubation, five leaves or straws samples were taken from each replicate and cultured on CMA-PARPH medium and the fungal colony formation was monitored. The experiment was performed using completely randomized design with factorial experiments including three factors (substrate type, inoculum density and time), 10 treatments (0-9 g inoculum levels) and nine replicates. The results showed that the type of substrate (wheat straw and pistachio leaf) was very important for the fungal saprophytic survival in that this was significantly greater for the pistachio leaves. Time was also considered another critical factor for the fungal survival. With passing incubation time, saprophytic survival of the fungus declined. Further, it was demonstrated that increasing inoculum density would result in longer survivability of P. drechsleri and maximum fungal survival on substrate was obtained when inoculum density was at 9% (w/w).     

Saprotrophic capabilities as functional traits to study functional diversity and resilience of ectomycorrhizal community

In an accompanying editorial Dr Petr Baldrian made a case casting doubt on our recent work addressing the saprophytic potential of ectomycorrhizal (EM) fungi. Dr Baldrian’s statements illustrate a very valid truth: the book is still very much open on this subject. The point he raised that the only logical reason for these fungi to be responding to high carbon demand or decreased host photosynthetic capacity by up-regulating enzymes is for the purpose of carbon acquisition is valid as well. Despite this, he makes the case that there is no compelling evidence that EM fungi exhibit saprophytic activity. The concept central to Dr Baldrian’s conclusion is that even though some EM fungi possess the genes necessary for saprophytic behaviour and may even express these genes, EM fungi do not inhabit a position in the soil column that provides access to usable substrate. In this paper we present both previously published and newly obtained data that demonstrate that this assumption is erroneous, and we present arguments that place the saprophytic potential of EM fungi within a broad ecological context.     

乌鲁木齐南部山区朽木生地衣群落特征的初步研究

应用聚类分析方法对分布在乌鲁木齐南部山区森林生态系统中朽木生地衣群落进行了数量分类并对群落结构、物种多样性、相似性和均匀度等群落参数进行了比较系统的研究。结果表明,乌鲁木齐南部山区的朽木生地衣共计40种,隶属于6目12科和20属,朽木生地衣形成4种群落：（1）枪石蕊＋喇叭石蕊群落;（2）亚花松萝＋茸刺褐梅＋优果小网衣群落;（3）犬地卷＋分指地卷＋裂芽地卷群落;（4）柳茶渍＋土星猫耳衣＋粉石蕊群落。群落3和群落4的相似性比较高为0.768,次为群落2和群落3的相似性为0.647;群落2的多样性最大为1.957,群落4的多样性最小为1.365。同时发现在乌鲁木齐南部山区森林生态系统中朽木生地衣群落的分布与海拔高度和朽木的种类有密切的关系,不同海拔的不同类型的森林生态系统中分布着不同种类的朽木生地衣植物。     

腐生型兰科植物研究进展

腐生型兰科植物又称完全菌根异养型兰(Fully Mycoheterotrophic Orchids),无绿叶,不含叶绿素,不能进行光合作用制造有机物,完全依靠与其共生的真菌提供营养。近年来,腐生兰独特的生活方式引起了生物学家对其生理生态及进化问题的广泛关注,但目前仍缺乏系统深入的研究。为此,作者通过整理《中国植物志》和近年来报道的相关文献,发现分布在中国的腐生型兰科植物约有23属81种,主要集中在天麻属(Gastrodia)(24种)、鸟巢兰属(Neottia)(8种)、无叶兰属(Aphyllorchis)(6种)、山珊瑚属(Galeola)(5种)等。由于腐生兰特殊的营养需求,相比于其他营养类型的兰科植物,其菌根真菌有较大区别。腐生兰的菌根真菌主要有两大类,即外生菌根真菌(Ectomycorrhizal fungi,ECM)和非丝核菌类的腐生菌(Non-rhizoctonia SAP fungi)。该文还综述了腐生兰与其菌根真菌的专一性、营养来源以及系统进化等问题,提出了目前研究存在的问题,并对今后的研究工作进行了展望,以期为腐生兰的资源保护及再生研究提供参考。     

汕头地区甲真菌病病原菌流行病学研究

目的了解近年来汕头地区甲真菌病病原菌的种类和构成情况,掌握流行病学资料。方法对2005年12月～2008年12月间来我院皮肤科就诊的214例甲真菌病患者进行病甲标本真菌学检查和分析。结果214例患者分离出163株致病菌。酵母菌居首位,占53．99％,其中自念珠菌占22．09％,近平滑念珠菌占17．18％,热带念珠菌占6．75％,其他酵母菌占7．97％;皮肤癣菌居第2位,占37．42％,其中红色毛癣菌占23．93％,须癣毛癣菌占12．27％,断发毛癣菌占1．23％;霉菌居第3位,占8．59％,以曲霉和青霉为主,分别占3．07％和2．45％。结论汕头地区近年来甲真菌病病原菌为酵母菌、皮肤癣菌和霉菌,其中以红色毛癣菌、白念珠菌、近平滑念珠菌和须癣毛癣菌最常见。     

Contribution of hydrolytic enzymes produced by saprophytic fungi to the decrease in plant toxicity caused by water-soluble substances in olive mill dry residue

We studied the influence of saprophytic fungi on the toxic effect that the water-soluble substances in dry residues from olive (ADOR) have on the growth of plants. All saprophytic fungi were able to decrease the phytotoxicity of ADOR, although the toxicity of this residue did not decrease in the same way. Penicillium chrysogenum was able to reduce the toxicity of ADOR when this residue was applied at the highest dose of 15%. Fusarium lateritum, F. graminearum and Mucor racemosus were able to reduce the toxicity of ADOR when this residue was applied at the intermediate doses. However, F. oxysporum decreased the phytotoxicity of ADOR only when the residue was applied at the lowest dose of 2.5%. All saprophytic fungi tested produce endoglucanase, endopolymetylgalacturonase and endoxiloglucanase when grown in the presence of ADOR. A close relationship was found between the decrease in the phytotoxicity of ADOR and the amount of hydrolytic enzymes produced by the saprophytic fungi. These results shows that hydrolytic enzymes can be important in the degradation of phytotoxic substances present in olive mill dry residue.     

Oligonucleotides specific for pathogenic and saprophytic leptospira occurring in water

Sets of primers specific for both pathogenic (SPL) and saprophytic (SSL) Leptospira were designed from ribosomal 16S genes (rrs) available in databases. They were used as two sets of primer pairs for the PCR amplification of known pathogenic and saprophytic strains. It was possible to identify pathogenic strains by the use of SPL primers and saprophytic ones by SSL primers. Serovars from L. meyeri, of controversial pathogenicity status, confirmed the heterogeneity of the species representatives in this respect. Serovars ranarum, sofia and perameles were amplified by SPL and not SSL. Conversely, serovar semaranga was amplified by SSL and not SPL. In order to use SPL primers for the detection of pathogenic leptospires from a natural water environment, we set up an additional semi-nested PCR by employing a second internal primer which succeeded in detecting as few as 5 pathogenic leptospires per ml of water.     

Towards a two‐dimensional proteomic reference map of Bradyrhizobium japonicum CPAC 15: Spotlighting “hypothetical proteins”

The economic and ecological importance of the symbiosis of soybean with Bradyrhizobium japonicum strains is significant in several countries, particularly Brazil; however, up to now, only one complete and a draft genome for this species are available. In this study, we have obtained a proteomic reference map of B. japonicum strain CPAC 15 (=SEMIA 5079) – used in commercial inoculants for application to soybean crops in Brazil – grown under in vitro conditions. CPAC 15 belongs to the same serogroup as strain USDA 123, and both are known as the soybean bradyrhizobial strains with highest competitive and saprophytic known so far. To increase the precision of the proteomic map, we compared whole‐cell 2‐D protein gel‐electrophoresis profiles of CPAC 15 and of two related strains. One‐hundred and seventy representative spots, selected from the three profiles, were analyzed by MS. In total, 148 spots were successfully identified as cytoplasmic and periplasmic proteins belonging to diverse metabolic pathways, several of them related to the saprophytic and competitive abilities of CPAC 15. We attributed probable functions to 26 hypothetical proteins, including those involved in polyhydroxybutyrate metabolism, β‐lactamase, stress responses and aromatic compound degradation, all with high probability of being related to the saprophytic ability of CPAC 15. In addition, by providing valuable information about expressed proteins in B. japonicum in vitro, our results emphasize the importance of accurate functional annotation of uncharacterized expressed proteins, improving considerably our understanding of the legume–rhizobia symbiosis.