Showing papers in "Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology in 1985"
TL;DR: Isolated cells of Saccharomyces cerevisiae were mated by micromanipulation and the reproductive capacity of the resulting zygotes was determined: the mating frequency was dependent on the age of the parents: conjugations between young cells and cells which had completed more than two thirds of their life-span were very rare events.
Abstract: Isolated cells of Saccharomyces cerevisiae were mated by micromanipulation and the reproductive capacity of the resulting zygotes was determined. The mating frequency was dependent on the age of the parents: conjugations between young cells and cells which had completed more than two thirds of their life-span were very rare events. The life-span of a zygote was very similar to the life-span of its shorter-lived parent. If one of the parent cells had budded several times prior to fusion, the life-span of the zygote was reduced correspondingly, i.e. there was no 'rescue by hybridization.' In four crosses the distribution of buds on both of the parent cells was recorded. In three of these four crosses the buds were evenly distributed, and in one the alpha-parent had three times as many buds as the a-parent.
66 citations
65 citations
TL;DR: A detailed analysis was made of the capture and subsequent penetration of nematodes by the nematophagous fungus Arthrobotrys oligospora using different electron-microscopical techniques.
Abstract: A detailed analysis was made of the capture and subsequent penetration of nematodes by the nematophagous fungus Arthrobotrys oligospora using different electron-microscopical techniques. Capture of nematodes by this fungus occurred on complex hyphal structures (traps) and was effectuated by an adhesive coating, present on these trap cells. The adhesive layer was largely fibrillar in nature and was absent on cells of normal hyphae. Following capture, penetration hyphae were formed at those sites where the trap cell wall was anchored to the nematode cuticle by the adhesive. New walls of these hyphae were formed underneath the original trap cell walls, which were partly hydrolysed to allow growth and development of the penetration tubes through the adhesive coating towards the cuticle. Our observations indicated that the cuticle of the nematode was subsequently penetrated by the penetration tubes by mechanical means. After penetration a large infection bulb was formed from which trophic hyphae arose. Cytochemical experiments indicated that the sites of penetration of the cuticle were intensely stained for acid phosphatase activity. At later stages of infection activity of this enzyme was present throughout the nematode contents; the enzyme was most probably secreted by complex membranous structures associated with the cytoplasmic membrane of the infection bulb and the trophic hyphae.
62 citations
TL;DR: Cryptococcus albidus var.albidus produced an extracellular endo- Poly (1,4-α-d-galacturonide) glycanohydrolase EC 3.2.1 when grown in a synthetic medium containing one of a variety of pectic substances or galacturonic acid.
Abstract: Cryptococcus albidus var.albidus produced an extracellular endo-polygalacturonase (poly (1,4-α-d-galacturonide) glycanohydrolase EC 3.2.1.15) when grown in a synthetic medium containing one of a variety of pectic substances or galacturonic acid. The highest level of enzyme activity (15.5 VU-ml−1) was obtained after 72 h of growth on 1.0% low-methoxyl pectin. The enzyme, purified by gel filtration (Sephadex G-100) after repeated ammonium sulphate precipitation and dialysis, showed only one band by polyacrylamide gel electrophoresis and had the following properties: mol wt (MWr) 41000 dal; isoelectric point (pl) = 8.10 ± 0.10; optimum temperature and pH for activity around 37°C and pH 3.75, respectively; pH stability in the pH range 4.0 to 8.0; complete heat inactivation after 10 min at 55°C; Km and Vmax values 5.7· 10−1 mg·ml−1 and 5.1 · 10−1 mmoles·min−1, respectively.
58 citations
TL;DR: In mixed cultures initially inoculated with non-pasteurized activated sludge, a regular interruption of feed supply for 1 h per day resulted in selection of non-sporulatiog anaerobes, and the fermentation pattern changed to a production of propionate and acetate, with a concomitant reduction of gas production.
Abstract: A mineral salts medium containing 1% (w/v) glucose providing carbon-limited growth conditions was subjected to anaerobic acidogenesis by mixed populations of bacteria in chemostat cultures. The formation of butyrate was shown to be dependent on the presence of saccharolytic anaerobic sporeformers in the acid-forming population. By the use of pasteurized activated sludge as an inoculum a culture was obtained consisting solely of anaerobic sporeformers that gave rise to the formation of butyrate, acetate, hydrogen and carbon dioxide as the main fermentation products. No formation of propionate could be detected. In this culture, the role of sporulation was investigated by applying periods of starvation and a single-step lowering of dilution rate (shift-down). In an experiment using a mineral salts medium supplemented with 1% (w/v) glucose and 0.5% (w/v) casein hydrolysate formation of refractile forespores as well as cell lysis could be demonstrated after 6 h starvation. In mixed cultures, initially inoculated with non-pasteurized activated sludge, a regular interruption of feed supply for 1 h per day resulted in selection of non-sporulating anaerobes. The fermentation pattern changed to a production of propionate and acetate, with a concomitant reduction of gas production. Similar results were obtained with shift-down in dilution rate. A relative increase of propionate-forming bacteria was accomplished in a continuous culture experiment with regular two times 2-h periods of starvation per day. The propionate-forming microbial population consisted predominantly of curved rods, tentatively identified as Selenomonas sp.
49 citations
TL;DR: The results of a large number of studies on microorganisms subjected to various degrees of substrate limitation have led to the idea that many species are particularly well adapted to growth at a very low rate at extremely low nutrient concentrations.
Abstract: The results of a large number of studies on microorganisms subjected to various degrees of substrate limitation have led to the idea that many species are particularly well adapted to growth at a very low rate at extremely low nutrient concentrations. The possible similarity between this type of bacteria and oligotrophic species is discussed. Some attention is paid to the problem of predicting the competitiveness of microbial species. To this end the apparent specific affinity of an organism for a given substrate is discussed in some detail. It is attempted to bring terminology used in describing this parameter in line with that commonly used in microbial physiology and ecology. Using one particular field study as an example the possible usefulness and limitations of this concept in field studies are discussed.
44 citations
TL;DR: Assimilation of putrescine as sole source of carbon and energy may be a valuable diagnostic criterion in yeast taxonomy.
Abstract: Yeast strains utilizing uric acid, adenine, monoamines or diamines as sole source of carbon and energy were isolated from several soil samples by the enrichment culture method. The most common species wasTrichosporon cutaneum. Strains ofCandida catenulata, C. famata, C. parapsilosis, C. rugosa, Cryptococcus laurentii, Stephanoascus ciferrii andTr. adeninovorans were also isolated. All strains utilizing uric acid as sole carbon source utilized some primaryn-alkyl-l-amines hydroxyamines or diamines as well. The ascomycetous yeast strains showing these characteristics all belonged to species known to assimilate hydrocarbons. Type strains of hydrocarbon-positive yeast species which were not found in the enrichment cultures generally assimilated putrescine, some type strains also butylamine or pentylamine, but none assimilated uric acid. Methanol-positive species were not isolated. Type strains of methanol-positive and of hydrocarbon-negative species did not assimilate uric acid, butylamine or putrescine. Assimilation of putrescine as sole source of carbon and energy may be a valuable diagnostic criterion in yeast taxonomy.
40 citations
TL;DR: Strains ofYarrowia lipolytica forming exclusively spherical ascospores were developed through inbreeding and are more suitable for micromanipulation than other inbred strains forming helm-shaped ascospore.
Abstract: Strains ofYarrowia lipolytica forming exclusively spherical ascospores were developed through inbreeding. These strains are more suitable for micromanipulation than other inbred strains forming helm-shaped ascospores. External factors affecting sporulation frequency and tetrad formation in this yeast were investigated. Optimal formation of complete tetrads occurred at a narrow range of pH values around 6.0. Citrate was found to stimulate sporulation strongly. A synthetic medium containing citrate was developed to obtain standard conditions for maximum sporulation.
34 citations
TL;DR: The development of electron-dense microbodies in cells of capture organs of the nematophagous fungus Arthrobotrys oligospora was studied with different ultrastructural techniques and suggested that their presence must be explained by dilution of organelles in newly formed cells.
Abstract: The development of electron-dense microbodies in cells of capture organs of the nematophagous fungus Arthrobotrys oligospora was studied with different ultrastructural techniques. Kinetic experiments revealed that the synthesis of these microbodies started in a very early stage of trap formation; the organelles originated from special regions of endoplasmic reticulum by budding. Mature organelles were surrounded by a single membrane of approximately 9 nm (KMnO4-fixation) and lacked crystalline inclusions. The presence of the electron-dense microbodies was independent of the conditions during which the traps had developed. The organelles remained intact during aging of the trap cells. They were also observed in the trophic hyphae after capture and penetration of nematodes. However, the distribution patterns of these organelles in the trophic hyphae, which were identical to those observed after germination of isolated traps on different cultivation media, suggested that their presence must be explained by dilution of organelles in newly formed cells.
32 citations
TL;DR: Septa of species of Sporothrix exhibited three types of pores: (a) micropores which were central if single, or scattered; (b) central simple pores with Woronin bodies; (c) dolopores, which confirm the heterogeneity of the genus Sporothsrix.
Abstract: Transmission electron micrographs of septa in Blastobotrys species invariably showed central micropores. Septa of species of Sporothrix, however, exhibited three types of pores: (a) micropores which were central if single, or scattered; (b) central simple pores with Woronin bodies; (c) dolopores. The results confirm the heterogeneity of the genus Sporothrix.
32 citations
TL;DR: Limited attempts at enzyme purification and limitations in the formerly available analytical techniques for polysaccharide breakdown products have no doubt influenced the results obtained and thus the conclusions drawn.
Abstract: In a study on the possible use of plant inulin as an alternative source of fructose we have screened a large number of bacterial and yeast species for their ability to produce inulinase. Since inulinand levan-degrading capacities were often found to be present together in one species, this screening prompted a general survey of fructan-degrading abilities among bacteria and yeasts. As shortly after the oral presentation of our paper a review on microbial inulinases was published (Vandamme and Derycke, 1983), which especially dealt with enzymes of fungal and yeast origin, the emphasis in this report will be placed on bacterial fructanases; yeasts fructanases will be covered only briefly. Both inulin and levan are polyfruetosides, which however differ in some respects. Inulins are mainly of plant origin, though fungal (Aspergillus sydowi) and bacterial (Streptococcus mutans) inulin-type frnctans are known (Loewenberg and Reese, 1957; Baird et al., 1973). Plant inulins are usually linear !3-(2--, 1)-linked polyfructosides with a terminal glucose unit and a degree of polymerization of up to 35 40, and thus a tool wt of about 6000 dal. Fungal and bacterial inulins, on the other hand, are high-molecular weight (up to 2.107 dal; Kawai et al., 1973; Rosell and Birkhed, 1974) fructose polymers, with varying degrees of branching at C6. Levans are produced by numerous bacterial species (Fuchs, 1959) and, like bacterial inulins, consist of branched molecules (Marshall and Weigel, 1980b) of high tool wt (up to 108 dal) with predominantly 13-(2~ 6)-linkages, and branched at C1. Since, like inulins, levans are usually formed from sucrose, they resemble inulins by possessing a 13-(2~ 1)-linked terminal glucose moiety. Structurally related to inulins and levans are a great diversity of oligofructans which are of ubiquitous occurrence in various plant families (Fuchs, 1958). The literature on inulinases and levanases is rather confusing. Limited attempts at enzyme purification and limitations in the formerly available analytical techniques for polysaccharide breakdown products have no doubt influenced the results obtained and thus the conclusions drawn. However, on the basis of our present knowledge an enzyme classification as outlined in Table 1 can be made. From this Table it is evident that there are two types of enzymes involved in fructan degradation: hydrolases and transferases. Further, within the hydrolases there is a gradual 'transition' from exoand endofructanases, with high specificity for (poly)fructans, to 'invertase', with mostly only (very)
TL;DR: Aerobic denitrification would be of survival value in an environment where the ability to grow rapidly while denitrifying is important, but where limiting amounts of oxygen may be available.
Abstract: Thiosphaerapantotropha (Robertson and Kuenen, 1983), a new species isolated from a denitrifying, sulphide-oxidizing wastewater treatment plant, is capable of active denitrification in the presence of substantial amounts of oxygen. This is contrary to eurreaat belief. During studies on its denitrification system, Thiosphaera pantotropha was found to be capable of immediate denitrification after aerobic growth (Robertson and Kuenen, 1983). This suggested that the organism might have constitutive nitrate-reducing enzymes. Subsequent experiments using Kluyver flasks to ensure thorough aeration, and incorporating an oxygen electrode, showed that with the dissolved oxygen at at least 80~ of air saturation the cultures receiving nitrate grew faster than those without. They also gave a protein yield intermediate between those obtained with aerobic cultures lacking nitrate and anaerobic cultures provided with nitrate. A similar effect was observed when nitrite was used. Both the dissimilatory nitrate and nitrite reductases were present in cells grown on nitrate, but only nitrite reduetase levels were significant in cells grown on nitrite or without a nitrogen oxide. Sufficient nitrate had disappeared from the culture to account for half of the acetate oxidized to CO2. The remainder of the acetate must have been oxidized via oxygen. During these experiments, nitrite was found in the acetate cultures not supplied with nitrate or nitrite. Even in cultures supplied with 5 mM nitrite, the nitrite level rose, reaching a peak just before the end of the logarithmic phase. After this, the nitrite concentration rapidly fell. This phenomenon, known as heterotrophic nitrification, may account for the nitrite reductase found in cells grown without a nitrogen oxide. Its physiological significance remains to be studied. Aerobic denitrification would be of survival value in an environment where the ability to grow rapidly while denitrifying is important, but where limiting amounts of oxygen may be available.
TL;DR: A taxonomic description of Embellisia annulata sp.
Abstract: A taxonomic description of Embellisia annulata sp. nov. is provided and the relation of the fungus to superficially similar, annellidic genera of dematiaceous Hyphomycetes is discussed. Some physiological properties of E. annulata are mentioned.
TL;DR: The morphological and physiological characters of the species of Blastobotrys, and of a number of similar species of Sporothrix, Trichosporiella and Candida were studied.
Abstract: The morphological and physiological characters of the species of Blastobotrys, and of a number of similar species of Sporothrix, Trichosporiella and Candida were studied. Blastobotrys is defined as having mother cells (primary conidia) which form distinct, secondary conidia. Sporothix has non-catenulate conidia, or the conidia are catenulate without marked differentiation of conidia of first and second order. Trichosporiella is delimited from Candida by a stronger coherence between hyphal cells, arthroconidia being absent. Four new Blastobotrys species are described, and two unnamed species; two new combinations are proposed in Trichosporiella. Related species in other genera are briefly discussed. A new Stephanoascus teleomorph is described in two strains originally identified as Sp. fungorum. Two diagnostic keys to the described taxa, using either morphological or physiological characters, are given.
TL;DR: An oil-degrading bacterium identified as Acinetobacter lwoffi was isolated by elective culture on North Sea Forties crude oil from an activated sludge sample andence is presented for a relationship between aromatic amino acid catabolism and 1-phenyldodecane degradation in this organism.
Abstract: An oil-degrading bacterium identified as Acinetobacter lwoffi was isolated by elective culture on North Sea Forties crude oil from an activated sludge sample. It grew on a wide range of n-alkanes (C12−C28) and 1-phenylalkanes, including 1-phenyldodecane, 1-phenyltridecane and 1-phenyltetradecane. The organism degraded 1-phenyldodecane to phenylacetic acid which was further metabolized via homogentisic acid, whilst 1-phenyltridecane was transformed to trans-cinnamic and 3-phenylpropionic acid which were not further metabolized. Evidence dence is presented for a relationship between aromatic amino acid catabolism and 1-phenyldodecane degradation in this organism.
TL;DR: Within the hyphomycete genus Sporothrix Hektoen & Perkins three distinct groups are recognized on the basis of carbohydrate patterns, and in Blastobotrys Klopotek, mannose is predominant while xylose and rhamnose are absent; this suggests a relationship with the Ascoideaceae.
Abstract: Within the hyphomycete genus Sporothrix Hektoen & Perkins three distinct groups are recognized on the basis of carbohydrate patterns. In the first group, and in Blastobotrys Klopotek, mannose is predominant while xylose and rhamnose are absent; this suggests a relationship with the Ascoideaceae. A second group, comprising anamorphs of Ophiostomataceae, is characterized by the presence of rhamnose. A third group is characterized by the presence of xylose, indicating a basidiomycete affinity. Three sections are erected to accommodate these groups.
TL;DR: The results obtained with artificially contaminated, sterile food samples were similar to those obtained with B HI broth, but the degree of decrease in TNase activity in food was much lower than that in BHI broth.
Abstract: was not inhibited after 48 h incubation at 20 ~ in the presence of B. subtilis and S. faecalis var. liquefaciens but significant inactivation could be demonstrated at 25 ~ to 37 ~ The results obtained with artificially contaminated, sterile food samples were similar to those obtained with BHI broth, but the degree of decrease in TNase activity in food was much lower than that in BHI broth (Daoud and Debevere, 1984). Abundant growth ofB. subtilis or S.faecalis var. liquefaciens caused purified staphylococcal enterotoxin A levels to decrease during a 2-day incubation in BHI broth and supernatant fluid by 89 and 67~, respectively. Both staphylococcal TNase activity and staphylococcal enterotoxin A (SEA) production decreased in the presence of the test strains. Staphylococcal TNase activity decreased by 75 and 78% in the presence of B. subtilis and S. faecalis var. liquefaciens, respectively, while SEA production decreased by 95 and 65%, respectively, in the presence of these test strains. The results obtained with artificially contaminated sterile chicken or beef samples were similar to those obtained with BHI broth. Staph. aureus grew very well in heated vegetables. TNase was undetectable, although SEA could be detected. In the presence of B. subtilis or S. faecalis var. liquefaciens SEA production was reduced to a non-detectable level.
TL;DR: The starch-degrading yeastCandida tsukubaensis CBS 6389 secreted amylase at high activity when grown in a medium containing soluble starch, and the enzyme proved to be a glycoprotein with a molecular weight of 56000.
Abstract: The starch-degrading yeastCandida tsukubaensis CBS 6389 secreted amylase at high activity when grown in a medium containing soluble starch. The extracellular α-amylase activity was very low. The major amylase component was purified by DEAE-Sephadex A-50 chromatography and Ultrogel AcA 44 gel filtration and characterized as a glucoamylase. The enzyme proved to be a glycoprotein with a molecular weight of 56000. The glucoamylase had a temperature optimum at 55°C and displayed highest activity in a pH range of 2.4–4.8. Acarbose strongly inhibited the purified glucoamylase. Debranching activity was present as demonstrated by the release of glucose from pullulan.
TL;DR: Transfer of cells, precultured on glucose or glycerol, into uric acid-containing media indicated that these microbodies originated from the organelles, originally present in the inoculum cells, by growth and division.
Abstract: Growth of Candida famata and Trichosporon cutaneum on uric acid as the sole source of carbon and nitrogen was associated with the development of a number of microbodies in the cells. Cytochemical staining experiments showed that the organelles contained urate oxidase, a key enzyme of uric acid metabolism, and catalase. Transfer of cells, precultured on glucose or glycerol, into uric acid-containing media indicated that these microbodies originated from the organelles, originally present in the inoculum cells, by growth and division. In urate-grown C. famata the microbodies were frequently observed in large clusters; in both organisms they existed in close association with mitochondria and strands of ER. The organelles lacked crystalline inclusions. In freeze-fractured cells their surrounding membranes showed smooth fracture faces. Exposure of urate-grown cells to glucose-excess conditions led to a rapid inactivation of urate oxidase activity but catalase was only slightly inactivated. Glucose-induced enzyme inactivation was not associated with the degradation of the microbodies present in the cells. Similarly, repression of urate oxidase synthesis by ammonium ions also did not lead to the degradation of peroxisomes.
Journal Article•
TL;DR: In this paper, the growth kinetics of Streptomyces coelicolor A3(2), the wild-type strain, and 5802, a mutant incapable of utilizing agar as the sole carbon and energy source, have been studied on solid medium.
Abstract: Colony growth kinetics of Streptomyces coelicolor A3(2), the wild-type strain, and 5802, a mutant incapable of utilizing agar as the sole carbon and energy source, have been studied on solid medium. General features comparable to colony growth of filamentous fungi were observed in both streptomycete strains. Hyphal frequency at the margins of colonies was assessed as the number of hyphae crossing an arc of defined length and increased in an exponential manner with distance from the margin, reaching a maximum at approximately 200 pm. Aerial hyphal initials were formed approximately 350 pm from the margin. Colony radial extension was linear, but in the wild-type strain grown at low medium depths, growth was sometimes multiphasic, with successive phases of linear growth each exhibiting a slower radial growth rate than that of the preceding phase. Hyphal frequency at the colony margin decreased as colony diameter increased, indicating significant changes in environmental conditions in the peripheral growth zone during colony growth. In the primary phase of linear growth, the colony radial growth rate of both strains was independent of medium depth and in the absence of a cellophane membrane was independent of glucose concentration. Colony radial growth rate of strain 5802 growing on a cellophane underlay increased with glucose concentration. Hyphal frequency of strain A3(2) increased gradually with medium depth but was independent of glucose concentration. In strain 5802, hyphal frequency exhibited a strong dependence on both medium depth and glucose concentration. A threshold glucose concentration for growth was not found and inhibition of strain A3(2) occurred above 1 g 1-l. The results agree with many aspects of accepted theories for colony growth of both unicells and filamentous fungi, but suggest production of staling products and/or secondary metabolites to be of equal significance to nutrient limitation in controlling colony development.
TL;DR: The data suggest that both protein and lipoteichoic acid may be involved in cell surface hydrophobicity of B. bifidum subsp.pennsylvanicum, which was shown to possess a strongly hydrophobic cell surface.
Abstract: The possible role of lipoteichoic acid with respect to cell surface properties ofBifidobacterium bifidum subsp.pennsylvanicum was studied. Standard suspensions of bacteria were mixed with octane or xylene.B. bifidum subsp.pennsylvanicum was shown to possess a strongly hydrophobic cell surface. Hydrophobicity of the bacteria could be reduced by treatment with trypsin, pepsin (at pH 4.5), HCl and penicillin. The latter treatment resulted in an increased excretion of lipoteichoic acid. Albumin was capable of inhibiting the adherence to octane when it was present in the assay buffer. The data suggest that both protein and lipoteichoic acid may be involved in cell surface hydrophobicity. A great divergence in cell surface properties was observed within the genusBifidobacterium.
TL;DR: Despite inconsistencies in results between different assay methods for the conventional Entner-Doudoroff (ED) enzymes, the data indicated the route was enzymatically possible and a scheme for the inter-relationships of routes of gluconate metabolism is discussed.
Abstract: In addition to the ability of Penicillium notatum to grow on sucrose, glucose, fructose and gluconate, substantial growth occurred on 2-ketogluconate and 5-ketogluconate thereby indicating a diverse sugar metabolism. Cell-free extracts contained all the enzymes of the Embden-Meyerhof-Parnas pathway and for both oxidative and non-oxidative pentose phosphate metabolism. Despite inconsistencies in results between different assay methods for the conventional Entner-Doudoroff (ED) enzymes, the data indicated the route was enzymatically possible. Demonstrations of the activities of the enzymes of the non-phosphorylative equivalent of the ED pathway were achieved. No evidence was found of a phosphorylative linking enzyme between the two pathways. Both 2- and 5-ketogluconate reductases were detected along with gluconate dehydrogenase which suggested interconvertibility between the ketogluconates and gluconate. However, ketogluconokinase, responsible for the conversion of ketogluconate to 2-keto-6-phosphogluconate, was not detected. A scheme for the interrelationships of routes of gluconate metabolism is discussed.
TL;DR: An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of total anti-Campylobacter immunoglobulins in human sera and a high association was demonstrated between the severity of Campylobacteria-related symptoms and antibody titre values.
Abstract: An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of total anti-Campylobacter immunoglobulins in human sera. In this assay disintegratedCampylobacter bacteria were used as the antigen. Absorption tests including other possibly enteropathogenic bacterial species showed that the ELISA system displayed a high immunological specificity forCampylobacter. Using this ELISA it was found that in about 80% ofCampylobacter patients theseCampylobacter antibodies are produced to almost maximal levels within 8 days after onset of disease, and that they may persist for at least 4 months. Indeed,Campylobacter antibodies were demonstrated at low levels in a large number of control sera. However, accepting an antibody titre of 1: 640 as indicative ofCampylobacter infection, the statistical sensitivity of the ELISA system was 77% and the specificity 95%. In an epidemiological survey a high association was demonstrated between the severity ofCampylobacter-related symptoms and antibody titre values. Assessment ofCampylobacter antibody titres by means of this ELISA and by a complement fixation test in 92 sera from index patients and contacts with and without symptoms showed a high association of results.
TL;DR: Enterobacter cloacae H478 and Klebsiella edwardsii S15 were shown to harbour a relatively large conjugative plasmid that coded for cloacin DF13-susceptibility and the production and uptake of a hydroxamate iron chelator, most probably aerobactin.
Abstract: BothEnterobacter cloacae H478 andKlebsiella edwardsii S15 were shown to harbour a relatively large conjugative plasmid that coded for cloacin DF13-susceptibility and the production and uptake of a hydroxamate iron chelator, most probably aerobactin. Protein-blotting experiments with antiserum raised against the purified cloacin DF13/aerobactin receptor protein fromEscherichia coli (Co1V-K30) revealed that the corresponding outer membrane receptor proteins ofEnt. cloacae H478 andK. edwardsii S15 had apparent mol wts of 85 000 and 76000, respectively.E. coli transconjugants harbouring either the plasmid fromEnt. cloacae H478 orK. edwardsii S15 expressed a cloacin DF13/aerobactin outer membrane receptor protein with a mol wt of 74000. The receptor protein encoded by theEnt. cloacae andK. edwardsii plasmids were immunologically more related to each other than to the pCo1V-K30-encoded receptor protein.
TL;DR: Research was carried out in thirteen food industries and three non-food industries to answer the question whether pathogenic bacteria may be found on the hands of workers, and how contamination has taken place (by contact with raw materials or dirty surfaces or by bad toilet-hygiene).
Abstract: In recent years, we have investigated the influence of handling on the microbiological quality of foods, and the importance of hand hygiene (De Wit and Kampelmacher, 1981, 1982). Research has been carried out in thirteen food industries and three non-food industries, to answer the question whether pathogenic bacteria may be found on the hands of workers, and how contamination has taken place (by contact with raw materials or dirty surfaces or by bad toilet-hygiene). The results may be important in the discussion about the possibility that Salmonella-carriers contaminate foods by their hands. For sampling the hands a rinsing method was used as described by De Wit and Kampelmacher (1981).
TL;DR: Changes in enzyme activities, pyruvate accumulation and its subsequent metabolism were related to growth rate and the developmental cycle, and are discussed in conjunction with the regulatory role of calcium.
Abstract: Experiments examined the metabolic basis of Ca2+-induced conidiation during the 12-h period following the addition of Ca2+ to 40-h vegetative cultures ofPenicillium notatum. Vegetative mycelium had enzymic capacity for three routes of glucose catabolism viz. the Embden-Meyerhof-Parnas (EMP), pentose phosphate (PP) and the Entner-Doudoroff (ED) sequences. Inhibitors of EMP enzymes restricted vegetative growth more than that associated with conidiation whilst arsenate augmented the limited capacity of lower levels of Ca2+ to promote conidiation. Arsenite (5.6 mmol · 1−1) partially blocked the metabolism of pyruvate and caused its accumulation, which was also promoted by Ca2+ alone. Arsenite did not induce conidiation in vegetative cultures but when combined with Ca2+ it enhanced conidiation. Radiorespirometry and the analysis of accumulated pyruvate, promoted by arsenite, indicated that approximately 54% of carbon was catabolized via combined EMP/ED routes and 46% by the PP pathway and subsequently via a weakly functional TCA cycle. Calcium-induced cultures swung to a primarily ED (25%) and PP (75%) based catabolism with low substrate level phosphorylation, including a facility for a non-phosphorylative ED route, and further diminished oxidative TCA capacity. Pyruvate accumulation in Ca2+-induced cultures coincided with the decline in activity of pyruvate dehydrogenase and a reduced capacity for gluconeogenesis, with other enzymes of pyruvate metabolism showing altered activities. These changes in enzyme activities, pyruvate accumulation and its subsequent metabolism were related to growth rate and the developmental cycle, and are discussed in conjunction with the regulatory role of calcium.
TL;DR: Serotyping and hippurate hydrolysis data confirm the conclusions from epidemiological investigations, according to which poultry is a major source of human campylobacteriosis, while pigs are rarely so.
Abstract: Three hundred strains of Campylobacter jejuni, isolated from human patients, poultry and pigs were serotyped according to the Penner-Lauwers system and furthermore tested for hippurate hydrolysis. Serotyping showed a close relationship between human and chicken strains, whereas there was little relationship between human and pig strains. A similar conclusion was drawn from the results of the hippurate hydrolysis test: 86% of human and 94% of poultry strains were positive, whereas 91% of pig strains were negative. These data confirm the conclusions from epidemiological investigations, according to which poultry is a major source of human campylobacteriosis, while pigs are rarely so.
TL;DR: Evidence is presented for the mitochondrial localization of the antimycin A (AA) + salicylhydroxamate (SHAM)-insensitive respiration of the yeasts Kluyveromyces lactis, Endomycopsis capsularis and Hansenula saturnus.
Abstract: In this paper evidence is presented for the mitochondrial localization of the antimycin A (AA) + salicylhydroxamate (SHAM)-insensitive respiration of the yeasts Kluyveromyces lactis, Endomycopsis capsularis and Hansenula saturnus Such a respiration, which can be sustained by NADH and NADPH but not by succinate, is inhibited by high concentrations of azide AA + SHAM-insensitive respiration is not phosphorylating and its postulated physiological role is to oxidize NADH
TL;DR: Based on data, strain NZ-2 could be characterized as the least and B. flavothermus as the most versatile of the three organisms.
Abstract: The lipid content and fatty acid composition of a strain ofBacillus caldolyticus and of two facultative thermophiles (B. flavothermus and strain NZ-2) were analysed after growth at different temperatures. In all three strains the amount of membrane, as a fraction of total cellular dry mass, was found to increase with temperature, however, in varying degrees. Changes of lipid content and protein/lipid ratio inB. caldolyticus between 60°C and 100°C and in strain NZ-2 between 45°C and 70°C were minor; inB. f avothermus the alterations in the 50°C–70°C range were more pronounced. The same was found for changes observed in the phospholipid/total lipid and phospholipid/membrane ratios, and also in the amounts of individual phospholipids. The alterations of the fatty acid composition were most significant inB. caldolyticus, especially between 80°C and 95°C. In contrast, the main changes inB. flavothermus and NZ-2 were found to occur between 30°C and 50°C, and between 45°C and 60°C, respectively. Based on these data, strain NZ-2 could be characterized as the least andB. flavothermus as the most versatile of the three organisms.
TL;DR: Prevalence of serum precipitins againstMicropolyspora faeni, Thermoactinomyces vulgaris andAspergillus fumigatus, employing the counterimmunoelectrophoresis and Ouchterlony's double diffusion techniques, is reported in 162 of the equines stationed at two military installations in northwestern India.
Abstract: Prevalence of serum precipitins againstMicropolyspora faeni, Thermoactinomyces vulgaris andAspergillus fumigatus, employing the counterimmunoelectrophoresis (COTE) and Ouchterlony's double diffusion (DD) techniques, is reported in 162 of the equines stationed at two military installations in northwestern India.M. faeni specific precipitins were demonstrable in 58 of 112 mules from site I in the mountainous region whereas the results were negative for all of the 50 horses examined from site IT located in the plains. Of the 58M. faeni positive mules, 45 (78%) had signs and symptoms suggestive of chronic obstructive pulmonary disease (COPD) while the remaining 13 (22%) were apparently free from any respiratory disorder. The more frequent occurrence ofM. faeni precipitins in the symptomatic than in the asymptomatic group of mules was found to be statistically significant (P < 0.01). Precipitins againstA. fumigatus were concomitantly demonstrated in 5 of the mules afflicted with COPD and found to be positive forM. faeni.