摘要:

A method to detect the expression of hemoproteins with organic hydroperoxide reducing activity was developed to screen bacterial populations isolated from heavy oils and oil sands. The method is based on the activity of cytochromeP-450 as catalyst in the reduction of cumene hydroperoxide by artificial electron donors. There was no cross-reactivity with true peroxidases involved in the reduction of hydrogen peroxide. Cross-reactivity with catalase could be eliminated with appropriate inhibitors but did not normally interfere with the detection method. A preliminary screen resulted in the isolation ofAcinetobacter calcoaceticusand a range of Gram-positive bacteria with organic peroxidase activity. Carbon monoxide difference spectra of cell-free extracts of the isolates revealed the presence of a hydrocarbon-inducible cytochromeP-450 inAcinetobacter calcoaceticusand in coryneform and actinomycete bacteria. A CO-binding cytochrome of unknown type with a Soret absorption maximum at 424 nm and cumene hydroperoxidase activity was also detected in some strains.

ISSN:0008-4166    

DOI:10.1139/m87-001

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

A numeric method is suggested for the treatment of microcalorimetric curves of bacterial growth to provide a new tool for their automatic identification. In this method the microcalorimetric curves are searched against certain reference profiles (stored in a library) by means of a cross-correlation analysis and a parametric comparison. The matching between the new curve and each reference profile is evaluated by means of a specific identification coefficient which provides an objective criterion for the identification of each species. The reliability of the method is discussed.

ISSN:0008-4166    

DOI:10.1139/m87-002

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Under submerged growth in a defined medium (TKI broth), the entomopathogenic fungus,Beauveria bassiana, produced conidia; it produced only blastospores in complex media. Production of such "submerged" conidia depended on the nature of the carbon source and the presence of nitrate as a nitrogen source. Maximum yield of conidia (5 × 108 mL) was obtained when glucose was the carbon source and when the glucose to nitrate ratio was 5:1. Other carbon sources gave rise to both conidia and blastospores. Reducing the phosphate concentration resulted in the production of conidia which resembled "aerial" conidia in morphology and germination rates. The surfaces of "submerged" conidia were relatively smooth, but had a tendency to acquire the rough, warty, brittle surface characteristics of aerial conidia. Blastospores produced in defined media gave rise to conidia through microcycle conidiation without going through the vegetative phase of growth. In more complex media, blastospores did not undergo microcycle conidiation.

ISSN:0008-4166    

DOI:10.1139/m87-003

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Twenty-two strains ofClostridiumspecies, including 7 each ofClostridium acetobutylicumandC.butylicum, grew well when supplied with common hexose and pentose carbohydrates as sole carbon sources. Glucosamine and galacturonic acid were used by most strains, but glucuronic acid supported the growth of relatively few. Rhamnose was used, to various degrees, by all strains tested, but less acid was produced than observed from other carbohydrates. The major fermentation products from rhamnose included acetic acid, propionic acid, butyric acid, n-propanol, and 1,2-propanediol. Fermentation product concentration in batch culture was enhanced by inclusion of bicarbonate in the medium. With either arabinose or pyruvate as the source of carbohydrate, supplementation of the medium with 1,2-propanediol resulted in its conversion to propionic acid and n-propanol. With glucose as the carbohydrate source the conversion of 1,2-propanediol to propionic acid and propanol was repressed.

ISSN:0008-4166    

DOI:10.1139/m87-004

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Interbacterial adhesion between strains ofPseudomonas aeruginosaand strains of indigenous oral bacteria, both of which were isolated from the oral cavity of cystic fibrosis patients, was investigated by the phenomenon of the coaggregation reaction. A total of 22 strains ofP.aeruginosawere isolated from the oral cavitiy of 17 patients and examined for their abilities to coaggregate with 5 strains each ofStreptococcus sanguis,Streptococcus mitis,Actinomyces viscosus, andActinomyces naeslundii. Coaggregation reactions were common between these oral bacteria and both the mucoid and nonmucoid variants ofP.aeruginosa. All strains ofP.aeruginosawere also able to agglutinate neuraminidase-treated or untreated human erythrocytes of blood types A, B, and O. Positive coaggregation reactions were further characterized by determining the effects of several sugars, and of heat and protease treatments of the bacteria. None of the coaggregation reactions were inhibited by 0.05 Mlactose, galactose, glucose, fucose, or mannose. All coaggregation reactions were dependent upon heat- and protease-sensitive components of thePseudomonas. Thus, the interbacterial adhesions betweenP.aeruginosaand the oral bacteria studied appears to involve adhesins on thePseudomonascell, which bind to complementary receptors, on the cell surfaces of oral bacteria. The apparent prevalence and diversity of interbacterial adhesions betweenP.aeruginosastrains originating from the oral cavity of cystic fibrosis patients and strains of the indigenous oral bacteria suggest that some of these reactions may affect the extent to whichP.aeruginosacolonizes in the oral cavity of cystic fibrosis patients, and thereby, influence susceptibility of the host to infection.

ISSN:0008-4166    

DOI:10.1139/m87-005

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Factors affecting the sensitivity of the passive haemagglutination method for serotyping campylobacters have been studied. The concentration of red blood cells during the haemagglutination stage of the procedure markedly affected the titer obtained. An increase in concentration of red blood cells resulted in a lower titer, with titers being inversely proportional to red blood cell concentration. No differences in titer were observed when erythrocytes were sensitized at a range of pH values between pH 5.0 and pH 8.0. The time required for antigen extraction and for red blood cell sensitization was shown to be 15 min each, thus resulting in a reduction in the time required for serotyping. Furthermore, use of avian erythrocytes enabled the haemagglutination reactions to be read after incubation for only 1 h. Combining these procedures with a rapid slide haemagglutination test enables a single worker to serotype over 100C.jejuniandC.coliisolates within 1 working day.

ISSN:0008-4166    

DOI:10.1139/m87-006

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Characteristics of the plasma membrane ofSporothrix scheckiicells as revealed by freeze-fracture techniques have been classified into eight types (Y1, Y2a, Y2b, Y3a, Y3b, Y4a, Y4b, and Y5) in yeastlike cells grown under the following two conditions: brain heart infusion agar medium at 27 °C, and brain heart infusion agar medium at 37 °C. Type Y1 cells are yeastlike cells having smooth plasma membranes without any invagination. Typical characteristics of the other types are as follows: type Y2a, smooth plasma membranes with few trenchlike invaginations; type Y2b, wavy plasma membranes with few oval or irregularly formed invaginations; type Y3a, plasma membranes with many randomly distributed trenchlike invaginations; type Y3b, plasma membranes with many cocoonlike or irregularly formed invaginations; type Y4a, plasma membranes with longer trenchlike invaginations; type Y4b, plasma membranes with irregularly formed, enlarged invaginations; and type Y5, smooth or wavy plasma membranes with aggregations of intramembranous particles and with many vacuoles between cell walls and plasma membranes or in the cytoplasm in some cells. By counting the proportion of each type of yeastlike cell under the two conditions and with different cultivation periods, it appears that plasma membrane types change as aging progresses in the following order: type Y1, Y2a, Y3a, Y4a, and Y5 in conidia and type Y1, Y2b, Y3b, Y4b, and Y5 in yeastlike vegetative cells. These observations provide us with an important advantage when studying the effects of antifungal agents on the plasma membrane ofSporothrix scheckii, as it is important to know the natural course of changes in membrane structure during aging.

ISSN:0008-4166    

DOI:10.1139/m87-007

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

ArthrobacterP1grew readily with glucose or glycine as sole carbon source, but not withL-serine. However, mutants usingL-serine were readily isolated. These synthesized hydroxypyruvate reductase and serine/α-ketoglutarate transaminase constitutively. We suggest thatArthrobacterP1as originally isolated had the structural genes necessary to form these enzymes, but was not able to produce enyzmes from them.

ISSN:0008-4166    

DOI:10.1139/m87-008

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Four Regional Health Protection Branch laboratories each compared aerobic colony counts obtained after "stomaching" and blending, for a minimum of 10 samples in each of the seven food groups: dry pastas; chocolate and cocoa powders; frozen entrees (macaroni and cheese, chow mein, chop suey, fried rice, seafood casseroles, and Salisbury steak); nonfat dry milk; shrimp and crabmeats; spices; and breakfast sausages. Overall, counts obtained after using the Stomacher were equivalent to or higher than counts obtained after using the blender in 73% of the comparisons (α = 0.05). Where differences existed, counts obtained after using the Stomacher tended to be higher than counts obtained after using the blender from milk powder and lower from sausage. Aerobic colony counts from these foods are not unacceptably biased when obtained by Stomacher.

ISSN:0008-4166    

DOI:10.1139/m87-009

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Escherichia coliinjured by copper in carbonate buffer simulating the drinking water environment showed decreased oxygen utilization. Oxygraph measurements revealed that copper-injured bacteria had a rate of oxygen utilization that was less than 25% of that of control cells. Respirometry experiments measured rates over a longer period of time and showed similar trends. Nuclear magnetic resonanance spectroscopy (13C nmr) and gas chromatography were used to identify differences in metabolism between healthy and injured populations ofE.coli. The rate of glucose utilization by injured cells under anaerobic conditions was 64% of that of healthy cells. The rates of lactate and ethanol accumulation were 88 and 50% of the control, respectively. The13C nmr studies of oxygenated cultures revealed differences in the accumulation of acetate and glutamine. Aerobic utilization of glucose and succinate by injured cells were 87 and 21% of the rate of the controls, respectively. Additional studies revealed injured cells had a decreased ability to reduce 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) with a variety of carbohydrate substrates. Injured cells reduced greater quantities of INT than healthy cells when NADH was used as a substrate. A comparison of metabolic end products suggested that injured cells also had considerable differences in carbon flow compared with healthy cells.

ISSN:0008-4166    

DOI:10.1139/m87-010

出版商:NRC Research Press    

年代:1987

数据来源: NRC