摘要:

Resin acids, a group of diterpenoid carboxylic acids present mainly in softwood species, are present in many pulp mill effluents and toxic to fish in recipient waters. They are considered to be readily biodegradable. However, their removal across biological treatment systems has been shown to vary. Recent studies indicate that natural resin acids and transformation products may accumulate in sediments and pose acute and chronic toxicity to fish. Several resin acid biotransformation compounds have also been shown to bioaccumulate and to be more resistant to biodegradation than the original material. Until recently, the microbiology of resin-acid degradation has received only scant attention. Although wood-inhabiting fungi have been shown to decrease the level of resin present in wood, there is no conclusive evidence that fungi can completely degrade these compounds. In contrast, a number of bacterial isolates have recently been described which are able to utilize dehydroabietic or isopimaric acids as their sole carbon source. There appears to be an unusually high degree of substrate specificity with respect to the utilization of abietane congeners and the presence of substituents. Pimaranes do not appear to be attacked to the same extent as the abietanes. This paper reviews the occurrence, chemistry, toxicity, and biodegradation of resin acids in relation to the biological treatment of pulp and paper mill effluents.Key words: resin acids, biodegradation, pulp mill effluents.

ISSN:0008-4166    

DOI:10.1139/m97-086

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Nucleotide sequencing of a 3779-bp fragment of theStaphylococcus aureusbacteriophage 80α revealed two open reading frames: ORF1, designated aslytA, which encodes a polypeptide of 481 amino acids with an apparentMrof 53.81 kDa; and ORF2, designated as holin, which encodes for a hydrophobic polypeptide of 145 amino acids with an apparentMrof 15.58 kDa and exhibits two putative transmembrane helices. Both genes showed 100% sequence homology to that of the peptidoglycan hydrolase and holin genes of theS.aureusphagereported earlier. In addition, the downstream sequences of thelytAgene were homologous to the phage attachment site (attP) of the phage. Based on our data we propose that the lytic system of the phage 80α evolved from that of phage.Key words: attachment site, bacteriophage 80α, holin, peptidoglycan hydrolase,Staphylococcus aureus.

ISSN:0008-4166    

DOI:10.1139/m97-087

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

We report some characteristics of a ruminai bacterium (strain NPOH1) that metabolizes 3-nitropropanol, the toxic principle of various milk vetchs that are distributed worldwide. The gram-positive bacterium was nonmotile and did not produce spores. Growth of strain NPOH1 occurred under anaerobic conditions and was supported by the electron acceptors 3-nitropropanol, 3-nitropropionate, nitrate, 2-nitropropanol, nitroethane, nitroethanol, or 3-nitro-1-propyl-β-D-glucopyranoside (miserotoxin). Other potential electron acceptors, namely sulfate, sulfite, azide, chlorate, perchlorate, nitrite, fumarate, 2-nitrobutane, or nitrobenzene, did not support growth. Formate, lactate, and H2stimulated growth of strain NPOH1 in the presence of the appropriate nitrocompound, whereas a variety of other potential H2donors did not. When grown in medium containing both nitrate and either 3-nitropropanol or 3-nitropropionate, nitrate was the preferred acceptor. Strain NPOH1 reduced nitrate to nitrite and, when grown with excess reductant, nitrite was further reduced to ammonia. The products formed during the metabolism of 3-nitropropanol and 3-nitropropionate by mixed ruminal populations, 3-aminopropanol and β-alanine, were not found in culture fluids of strain NPOH1. Analysis of total cellular fatty acid profiles and of the mole percent guanine plus cytosine suggests that strain NPOH1 is a novel bacterium. The capacity of strain NPOH1 to metabolize 3-nitropropanol suggests that this organism may play an important role in detoxification of 3-nitropropanol in the rumen.Key words: nitropropanol, nitropropionate, anaerobic, rumen, detoxification.

ISSN:0008-4166    

DOI:10.1139/m97-088

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Immunofluorescence microscopy was used to detect in the mycoparasitePiptocephalis virginianathe presence of a complementary glycoprotein that binds specifically to the host cell surface glycoproteinsbandc, reported earlier from our laboratory. Germinated spores ofP.virginianatreated with cell wall extract of the hostMortierella pusilla, primary antibody prepared against cell wall glycoproteinsbandc, and fluorescein isothiocyanate (FITC) – goat anti-rabbit IgG conjugate showed fluorescence. Immunobinding analysis identified from the mycoparasite a protein of 100 kDa that binds with the host glycoproteinsbandc, separately as well as collectively. Its purification was achieved by (i) 60% ammonium sulfate precipitation, (ii) heat treatment, (iii) Sephadex G-100 gel filtration, and (iv) preparative polyacrylamide gel electrophoresis (PAGE). The purity was ascertained by sodium dodecyl sulphate (SDS) – PAGE and Western blot analysis. Positive reaction to periodic acid – Schiff s reagent revealed its glycoprotein nature, and mannose was identified as a major sugar component. The specificity of the polyclonal antibody raised against electrophoretically purified complementary protein in rabbit was confirmed by dot immunobinding and Western blot analyses. Immunofluorescence microscopy revealed surface localization of the protein on the germ tubes ofP.virginiana. Fluorescence was also observed at the surface of the germinated spores and hyphae of the hostM.pusilla, after treatment with complementary protein fromP.virginiana, primary antibody prepared against the complementary protein, and FITC – goat anti-rabbit IgG conjugate.Key words: biotrophic mycoparasite, cell surface agglutinin, glycoprotein immunobinding, immunofluorescence, mucoraceous host.

ISSN:0008-4166    

DOI:10.1139/m97-089

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

In a survey of plasmids in a variety of β-lactam antibiotic producingStreptomycesspp., two small linear plasmids (pSJL1 and pSJL2) of approximately 12 and 17.5 kb were detected withinStreptomyces jumonjinensisNRRL 5741, in addition to the previously reported giant linear plasmids pSJL3 and pSJL4. Characterization of these plasmids by Southern hybridization indicated that no significant homology exists between theS.jumonjinensisplasmids and plasmids detected in other β-lactam antibiotic producingStreptomycesspp. Single and double restriction endonuclease digestions were performed to generate maps of the two plasmids. The plasmids pSJL1 and pSJL2 have copy numbers of 21–27 and 15–20, respectively.Key words:Streptomyces, linear plasmid, DNA hybridization, DNA homology.

ISSN:0008-4166    

DOI:10.1139/m97-090

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

The mushroom soft rot bacteriumPseudomonas gladiolipv.agaricicolawas observed to cause pitting when inoculated onto tissues of several commercially important Japanese cultivated mushrooms. Scanning electron microscope studies demonstrated the sequential removal of hyphal wall layers, thereby exposing the chitin skeletal matrix, which in turn was degraded. A second type of damage typified by collapsed, shriveled, and in some cases lysed hyphal cells was also observed. Culture plate assays revealed thatPseudomonas gladiolipv.agaricicolaproduces chitinase and this, coupled with earlier evidence of a β-glucanase enzyme, accounted for the degradative ability of the pathogen. The gelatinous coating on thePholiota namekosporocarp appeared to confer resistance toPseudomonas gladiolipv.agaricicolaattack. Petri dish coincubations with several cultivated mushroom species indicated the ability ofPseudomonas gladiolipv.agaricicolato inhibit mycelial growth over a large distance and suggested the presence of a toxin or toxins. Owing to its wide host range,Pseudomonas gladiolipv.agaricicolais considered as a potential threat, not only to the mushroom industry in Japan but also to the mushroom industry in other tropical/subtropical countries.Key words: chitinase, disease,Pseudomonas gladiolipv.agaricicola, soft rot, toxin.

ISSN:0008-4166    

DOI:10.1139/m97-091

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

The interaction betweenAspergillus fumigatusconidia and murine macrophages of various origins was investigated. Cocultures were carried out betweenA.fumigatusstrains and freshly isolated murine pulmonary alveolar macrophages or two murine macrophage cell-lines: murine alveolar cell-line MALU and murine astrocytoma cell-line J774. By measuring the variation of elastolytic activity in the coculture supernatants with two elastin substrates, we demonstrated that either viable or fixedA.fumigatusorC.albicansyeasts or nonspecific particles induced significant macrophage elastolytic activity. The effect ofA.fumigatussupernatant or the purifiedA.fumigatusgalactomannan suggested also the possible involvement of this polysaccharide in macrophage-protease gene expression, release, and activity in invasive aspergillosis. The effect of inhibitory compounds demonstrated the potential implication of a macrophagic metalloprotease and a macrophagic cysteine protease. RNA analysis allowed us to demonstrate the induction of expression of two macrophagic protease genes in stimulated macrophages. Two distinctive mechanisms appeared to be implicated in macrophage protease induction: nonspecific phagocytosis in the earliest times of the coculture and (or) specific galactomannan recognition after its gradual release by the mycelium.Key words:Aspergillus fumigatus, macrophages, proteases, invasive aspergillosis, galactomannan.

ISSN:0008-4166    

DOI:10.1139/m97-092

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

There is an urgent need to develop rapid methods to determine the viability ofCryptosporidiumoocysts andGiardiacysts in environmental samples, especially water. The inclusion of the vital dye propidium iodide (PI) by oocysts and cysts has been previously shown to correlate well with nonviability. The ability of nonviable oocysts and cysts to include PI has been employed to develop a rapid viability determination method that could be used in conjunction with the current indirect fluorescent antibody (IFA) method for detecting oocysts and cysts. The efficacy of this PI–IFA method to detect and determine the viability status of oocysts/cysts has been tested using oocyst samples inactivated by three different approaches. The ability to incorporate PI staining with IFA detection provides the advantage of both detection and viability determination at the same time, using the same sample.Key words: propidium iodide, viability, oocysts, cysts, detection.

ISSN:0008-4166    

DOI:10.1139/m97-093

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Brownish-black spots and flecks several millimetres wide were frequently recognized on the surface and within nonpreservative-treated hardwood (Alstonia scholaris(R.Br.)) and softwood (Pinus sylvestrisL.) test stakes placed in an acid forest soil. Energy-dispersive X-ray microanalysis in conjunction with transmission electron microscopy (TEM) and gross chemical analysis of wood using inductively coupled plasma spectrometry showed the flecks to be composed primarily of Mn, which was selectively removed from the surrounding soil. A similar uptake of Mn into wood stakes placed in presterilized acid soil was not noted, indicating the process resulted from biotic activity. Detailed TEM observations showed intrusion of Mn into the wood cell lumina and into areas of erosion, cavity formation, and decayed middle lamella inAlstoniaand pine wood cells attacked by an unknown white rot decay fungus. Distinct zones of apparent delignification were also noted progressing across secondary cell walls and middle lamella regions of attacked cells, although it was unclear if the effect was caused by nonenzymatic attack by Mn, enzymatic attack by the fungus, or a combination of both. Mn is thought to play a major regulating role in both lignin depolymerization and mineralization in the presence of organic acids during white rot decay. Present observations also suggest that uptake of Mn into wood stakes during microbial degradation results from biotic activity and soil type and pH are of major significance.Key words: Mn, test stakes, electron microscopy, white rot decay, inductively coupled plasma spectrometry.

ISSN:0008-4166    

DOI:10.1139/m97-094

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Methylomicrobium albumBG8 uses methane as its sole source of carbon and energy. The oxidation of methane to methanol is catalyzed by the enzyme methane monooxygenase. Methane monooxygenase activity, intracytoplasmic membrane abundance, and cell mass increased with increasing copper concentration in the medium. When copper was added to copper-deficient cultures, cell mass and intracytoplasmic membrane structure increased. These findings are consistent with the presence of copper in the particulate methane monooxygenase. Methane monooxygenase activity and intracytoplasmic membrane abundance were correlated, suggesting that the methane monooxygenase may be involved in intracytoplasmic membrane proliferation.Key words:Methylomicrobium albumBG8, copper, intracytoplasmic membrane, methane monooxygenase.

ISSN:0008-4166    

DOI:10.1139/m97-095

出版商:NRC Research Press    

年代:1997

数据来源: NRC