Über die Einwirkung heterotropher Mikroorganismen auf die Zersetzung silikatischer Minerale     

Friedrich E. W. Eckhardt 《植物养料与土壤学杂志》1979,142(3):434-445

The effect of heterotrophic microorganisms upon the degradation of silicate minerals The purpose of the present work was to study the weathering activity of yeasts and filamentous fungi on various silicate minerals. Culture experiments were carried out on samples of amphibolite, biotite, and orthoclase. Finely ground powder was incubated with pure cultures of 5 yeast strains and 11 filamentous fungi in a glucose-mineral salts-solution at room temperature over a period of 12 weeks. Changes in pH as well as in concentrations of K, Ca, Mg, Fe, Al, and Si in the culture solutions were determined at various intervals.-All fungal strains tested lowered the pH of the culture liquid with or without minerals added from 5.7 to values as low as 1.6. This acidification was brought about by the microbial production of organic acids, especially of gluconic acid. The lowest pH values were found in flasks containing biotite. Acidification in flasks with orthoclase was less pronounced. The pH values found in flasks containing amphibolite were similar to those produced in cultures without mineral powder. From biotite, up to 62% K, 33% Mg, 29% Fe, 59% Al, and 6% Si were released. The solubilizing activity on orthoclase was less effective, and least that on amphibolite.-The importance of acidity and the chelating capacity of the microbially produced organic acids as well as the chemical and structural properties of the mineral with respect to weathering are discussed. The results show that heterotrophic microorganisms like yeasts and filamentous fungi may effectively attack silicate minerals and rocks.  相似文献   

Glomalin-related soil protein contains non-mycorrhizal-related heat-stable proteins, lipids and humic materials     

Adam W. Gillespie  Fran L. Walley  Andrew R.S. Ross  Kai-Uwe Eckhardt  Robert I.R. Blyth 《Soil biology & biochemistry》2011,43(4):766-777

Glomalin is reportedly a stable and persistent protein produced in copious quantities by mycorrhizal fungi and may be an important pool of organic N in soil. Glomalin-related soil protein (GRSP), however, is only operationally defined by its extraction method, and has been only poorly characterized at best. The goal of this study was to characterize the molecular structures within GRSP. Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy and pyrolysis field-ionization mass spectrometry (Py-FIMS) revealed that GRSP contains a consortium of proteins along with many impurities. Employing proteomic techniques, we found that glomalin itself may be a thioredoxin-containing chaperone; however, no homologies with proteins or DNA of mycorrhizal origin were detected. Proteomics techniques further revealed that this fraction contains large amounts of soil-related heat-stable proteins and proteins of non-mycorrhizal origin. Results of this research show that the current extraction procedure that defines GRSP yields a mixture of compounds and thereby overestimates glomalin stocks when quantified using the Bradford assay. The chemical nature of glomalin has yet to be conclusively determined; it is unlikely that the chemical structure of glomalin can be elucidated from the mixture extracted as GRSP. Instead, an investigation into the specific biochemistry of immunoreactive assays currently used to define GRSP, followed by proteomic characterization of monoxenic mycorrhizal cultures may be required to advance our understanding of the chemical nature and agronomic significance of GRSP in soils.  相似文献   

Multinucleate erythrocytes in a brown kiwi (Apteryx mantelli)     

EKP Jillings  BD Gartrell  KJ Morgan  DH Hopcroft 《New Zealand veterinary journal》2013,61(2)

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Different Culture Media Requirements of IVF and Nuclear Transfer Bovine Embryos   总被引：3，自引：0，他引：3  

GF Mastromonaco  E Semple  C Robert  GJ Rho  DH Betts  WA King 《Reproduction in domestic animals》2004,39(6):462-467

Important differences exist between in vitro fertilized (IVF) and nuclear transfer (NT) bovine embryos. Studies have shown that although in vitro development is comparable, post-implantation survival is greatly reduced in NT embryos. In this study, we compare serum and bovine serum albumin (BSA) supplementation during oocyte maturation and embryo culture of IVF and NT embryos. In experiment 1, oocytes and embryos were randomly distributed into different treatment groups consisting of synthetic oviductal fluid (SOF) medium supplemented with either serum, fatty acid-free BSA (FAF) or fraction V BSA during maturation and/or culture to assess IVF embryo development. In experiment 2, oocytes were matured in SOF + serum or SOF + FAF and reconstructed embryos were cultured in SOF + FAF to assess NT embryo development. Among the IVF treatment groups, a greater number of blastocysts were observed in the steer serum (SER) group (IVM and IVC in SOF + serum) on day 6; however, no significant differences were seen in blastocyst development from day 8 onwards. Hatching frequencies on days 8 and 9 were significantly greater in groups with serum, with the exception of FAF (IVM and IVC in SOF + FAF) on day 9. For the NT treatment groups, the presence of serum during IVM resulted in a higher proportion of MII oocytes and increased blastocyst development and hatching rates were compared with supplementation of FAF. These results indicate that both serum and FAF provide comparable embryo development for IVF but not for NT bovine embryos.  相似文献   

Subcutaneous granuloma caused by Mycobacterium avium complex infection in a cat     

R. MALIK  L. GABOR  P. MARTIN  DH MITCHELL  DJ DAWSON 《Australian veterinary journal》1998,76(9):604-607

A localised subcutaneous swelling developed on the nasal bridge of a cat receiving chemotherapy for alimentary tract lymphosarcoma. Cytological and histological examination of representative samples of the lesion demonstrated pyogranulomatous inflammation and abundant acid-fast bacilli. A Mycobacterium sp was cultured from tissue excised from the lesion. Extensive testing at three reference laboratories indicated the strain was a member of the Mycobacterium avium complex. The infection was treated successfully by cytoreductive surgery and a 6 weeks course of orally administered clofazimine.  相似文献   

Microsatellite and mating type markers reveal unexpected patterns of genetic diversity in the pine root‐infecting fungus Grosmannia alacris          下载免费PDF全文

T. A. Duong  Z. W. de Beer  B. D. Wingfield  L. G. Eckhardt  M. J. Wingfield 《Plant pathology》2015,64(1):235-242

Grosmannia alacris is a fungus commonly associated with root‐infesting bark beetles occurring on Pinus spp. The fungus has been recorded in South Africa, the USA, France, Portugal and Spain and importantly, has been associated with pine root diseases in South Africa and the USA. Nothing is known regarding the population genetics or origin of G. alacris, although its association with root‐infesting beetles native to Europe suggests that it is an invasive alien in South Africa. In this study, microsatellite markers together with newly developed mating type markers were used to characterize a total of 170 isolates of G. alacris from South Africa and the USA. The results showed that the genotypic diversity of the South African population of G. alacris was very high when compared to the USA populations. Two mating types were also present in South African isolates and the MAT1‐1/MAT1‐2 ratio did not differ from 1:1 (χ² = 1·39, P = 0·24). This suggests that sexual reproduction most probably occurs in the fungus in South Africa, although a sexual state has never been seen in nature. In contrast, the large collection of USA isolates harboured only a single mating type. The results suggest that multiple introductions, followed by random mating, have influenced the population structure in South Africa. In contrast, limited introductions of probably a single mating type (MAT1‐2) may best explain the clonality of USA populations.  相似文献   

The effect of thinning and clear‐cut on changes in the relative abundance of root‐feeding beetle (Coleoptera: Curculionidae) in Pinus taeda plantations in central Alabama and Georgia     

Yuan Zeng  Kathryn R Kidd  Lori G Eckhardt 《Pest management science》2014,70(6):915-921

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Pinus taeda L. response to differential inoculum density of Leptographium terebrantis colonized toothpicks     

Pratima Devkota  John K. Mensah  Ryan L. Nadel  George Matusick  Lori G. Eckhardt 《Forest Pathology》2019,49(1)

Bark beetle‐vectored ophiostomatoid fungi, Leptographium terebrantis, is inoculated on the roots and lower stems of stressed Pinus species during the feeding activity of bark beetle. To determine the exact host response following inoculation, it is critical to challenge the host with a realistic amount of fungal inoculum. Thus, we designed a series of stepwise experiments using L. terebrantis colonized toothpicks which focused on the inoculum transfer from the toothpicks to excised Pinus taeda stem segments and living saplings, respectively, at different inoculum densities. The toothpicks served as a substrate for fungal growth and sporulation and the inoculation showed their utility in eliciting host's response to the pathogen. The inoculated fungus caused blue‐stain and sapwood occlusions in P. taeda stems and saplings, respectively. The volume of occluded, visually damaged sapwood increased by 1.96 cm³ per radial inoculation point on average. Fungal colonized toothpicks can be used as a suitable alternative to agar discs for studying bark beetles vectored fungi and their host interactions.  相似文献   

Multivariate modeling of acoustomechanical response of 14-year-old suppressed loblolly pine (<Emphasis Type="Italic">Pinus taeda</Emphasis>) to variation in wood chemistry,microfibril angle and density     

Charles?Essien  Brian?K.?ViaEmail author  Qingzheng?Cheng  Thomas?Gallagher  Timothy?McDonald  Xiping?Wang  Lori?G.?Eckhardt 《Wood Science and Technology》2017,51(3):475-492

The polymeric angle and concentration within the S₂ layer of the softwood fiber cell wall are very critical for molecular and microscopic properties that influence strength, stiffness and acoustic velocity of wood at the macroscopic level. The main objective of this study was to elucidate the effect of cellulose, hemicellulose, lignin, microfibril angle and density on acoustic velocity and material mechanical properties of 14-year-old suppressed loblolly pine. Cellulose, hemicellulose and density are consistently the most important drivers of strength, stiffness and velocity. Cellulose and lignin are the highest and lowest contributor to velocity, respectively, with lignin acting as a sound wave dispersant, while cellulose is the most important conductor of sound wave at the molecular level, while hemicellulose acts as a special coupling agent between these components. The polymeric constituents are thus important drivers of sound wave propagation at the molecular level, while density played a subsequent role at the macroscale.  相似文献   

The Effect of Prostaglandin E₂ on the Cervices of Dioestrous and Prepartum Mares     

DH Volkmann  HJ Bertschinger  ML Schulman 《Reproduction in domestic animals》1995,30(4):240-244

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