scholarly journals The Oxygen Uptake of Suspensions and Cultures of a Free-living Bacterium

1937 ◽  
Vol 14 (2) ◽  
pp. 158-170
Author(s):  
JANE MEIKLEJOHN
Keyword(s):  
Oxygen Uptake ◽  
Stationary Phase ◽  
Bacterial Species ◽  
Maintenance Respiration ◽  
Free Living ◽  
Active Growth ◽  
Successive Sampling ◽  
Pure Cultures ◽  
Growth Respiration ◽  
Temperature Liquid

1. The oxygen uptake of pure cultures and suspensions of a free-living bacterial species has been measured at 26° C. 2. At this temperature, liquid cultures reach the maximum stationary phase of growth about 96 hours after inoculation. 3. The greatest total oxygen uptake was observed in samples taken from cultures 72 hours after inoculation, and the greatest uptake per cell at 48 hours after inoculation. The oxygen uptake in cultures which have reached the stationary state falls off rapidly, at each successive sampling, to a very low value. 4. In suspensions deprived of nitrogen, and showing no growth, and in cultures in the stationary phase, oxygen uptake proceeds at a constant rate. 5. In both suspensions and cultures, where active growth is taking place, the rate of oxygen uptake rises continuously; after a preliminary period of adjustment this rise is logarithmic. 6. The rise in oxygen uptake in a growing suspension is proportionately greater than the rise in bacterial numbers. 7. It is suggested that the oxygen uptake of a growing culture can be divided into two parts; "maintenance" respiration and "growth" respiration, and a technique is outlined for estimating the amount of oxygen uptake due to each factor.

scholarly journals Ice nucleation activity identified in some phytopathogenic Fusarium species

2005 ◽  
Vol 77 (2) ◽  
pp. 83-92 ◽  
Author(s):  
C. Richard ◽  
J.-G. Martin ◽  
S. Pouleur
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Species ◽  
Freezing Temperature ◽  
Ice Nucleation ◽  
Free Living ◽  
Factors Affecting ◽  
Pure Cultures ◽  
Nucleation Activity ◽  
Ice Nucleation Activity ◽  
Positive Controls

In order to know which species of Fusarium are ice nucleating and to determine the factors affecting their pathogenicity, ice nucleation activity (INA) was examined in Fusarium oxysporum, F. sporotrichioides, and F. tricinctum. Positive controls (lna+) used were F. acuminatum and F. avenaceum. The test for fungal INA was done with a simple and rapid tube nucleation assay. Twelve out of the 42 F. oxysporum isolates, and 8 out of 14 F. tricinctum isolates were lna+. No INA was detected in F sporotrichioides. In this test the threshold freezing temperature tended to increase with culture age, reaching a peak of -1°C in a few samples, which is as high as the warmest INA reported for bacteria, and higher than the INA detected in pure cultures of free-living fungi, lichen fungi, lichen algae and cyanobacteria. This is the first report of INA for F oxysporum.

scholarly journals Acanthamoeba-Campylobacter Coculture as a Novel Method for Enrichment of Campylobacter Species

2007 ◽  
Vol 73 (21) ◽  
pp. 6864-6869 ◽  
Author(s):  
Diana Axelsson-Olsson ◽  
Patrik Ellstr�m ◽  
Jonas Waldenstr�m ◽  
Paul D. Haemig ◽  
Lars Brudin ◽  
...  
Keyword(s):  
Culture Medium ◽  
Bacterial Species ◽  
Oxygen Quenching ◽  
Free Living ◽  
Promising Tool ◽  
Low Concentrations ◽  
Novel Method ◽  
Selective Antibiotics ◽  
Different Sources ◽  
Bacterial Concentrations

ABSTRACT In this study, we present a novel method to isolate and enrich low concentrations of Campylobacter pathogens. This method, Acanthamoeba-Campylobacter coculture (ACC), is based on the intracellular survival and multiplication of Campylobacter species in the free-living protozoan Acanthamoeba polyphaga. Four of the Campylobacter species relevant to humans and livestock, Campylobacter jejuni, C. coli, C. lari, and C. hyointestinalis, were effectively enriched by the coculture method, with growth rates comparable to those observed in other Campylobacter enrichment media. Studying six strains of C. jejuni isolated from different sources, we found that all of the strains could be enriched from an inoculum of fewer than 10 bacteria. The sensitivity of the ACC method was not negatively affected by the use of Campylobacter-selective antibiotics in the culture medium, but these were effective in suppressing the growth of seven different bacterial species added at a concentration of 104 CFU/ml of each species as deliberate contamination. The ACC method has advantages over other enrichment methods as it is not dependent on a microaerobic milieu and does not require the use of blood or other oxygen-quenching agents. Our study found the ACC method to be a promising tool for the enrichment of Campylobacter species, particularly from water samples with low bacterial concentrations.

scholarly journals Individual Mycobacterium tuberculosis Resuscitation-Promoting Factor Homologues Are Dispensable for Growth In Vitro and In Vivo

2004 ◽  
Vol 72 (1) ◽  
pp. 515-526 ◽  
Author(s):  
JoAnn M. Tufariello ◽  
William R. Jacobs, ◽  
John Chan
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Stationary Phase ◽  
Essential Gene ◽  
Micrococcus Luteus ◽  
Expression Patterns ◽  
Active Growth ◽  
Prolonged Incubation ◽  
Aerosol Infection

ABSTRACT Mycobacterium tuberculosis possesses five genes with significant homology to the resuscitation-promoting factor (Rpf) of Micrococcus luteus. The M. luteus Rpf is a secreted ∼16-kDa protein which restores active growth to cultures of M. luteus rendered dormant by prolonged incubation in stationary phase. More recently, the Rpf-like proteins of M. tuberculosis have been shown to stimulate the growth of extended-stationary-phase cultures of Mycobacterium bovis BCG. These data suggest that the Rpf proteins can influence the growth of mycobacteria; however, the studies do not demonstrate specific functions for the various members of this protein family, nor do they assess the function of M. tuberculosis Rpf homologues in vivo. To address these questions, we have disrupted each of the five rpf-like genes in M. tuberculosis Erdman, and analyzed the mutants for their growth in vitro and in vivo. In contrast to M. luteus, for which rpf is an essential gene, we find that all of the M. tuberculosis rpf deletion mutant strains are viable; in addition, all show growth kinetics similar to Erdman wild type both in vitro and in mouse organs following aerosol infection. Analysis of rpf expression in M. tuberculosis cultures from early log phase through late stationary phase indicates that expression of the rpf-like genes is growth phase-dependent, and that the expression patterns of the five M. tuberculosis rpf genes, while overlapping to various degrees, are not uniform. We also provide evidence that mycobacterial rpf genes are expressed in vivo in the lungs of mice acutely infected with virulent M. tuberculosis.

scholarly journals Production characteristics of the diatom Cylindrotheca closterium (Ehrenb.) Reimann et Lewin grown in an intensive culture at various nitrogen sources in the medium

2019 ◽  
Vol 4 (1) ◽  
pp. 33-44 ◽  
Author(s):  
S. N. Zheleznova
Keyword(s):  
Stationary Phase ◽  
Nitrogen Source ◽  
Nutrient Medium ◽  
Maximum Yield ◽  
Nitrogen Sources ◽  
Dry Weight ◽  
Sole Source ◽  
Active Growth ◽  
Cylindrotheca Closterium ◽  
Production Characteristics

The diatom Cylindrotheca closterium (Ehrenberg) Reimann et Levin is characterized by high productivity (up to 1.5 g·l-1·day-1) and the ability to accumulate a valuable carotenoid fucoxanthin (up to 2 % of dry weight). In the development of biotechnology based on microalgae, the key issue is the creation of concentrated nutrient medium. Nitrogen is one of the most important components in the nutrient medium that significantly affects the production characteristics of all microalgae. The aim of this study is to compare the production characteristics of C. closterium in an intensive storage culture using different forms of nitrogen in the medium. In the first experiment, nitrate and sodium nitrite, urea, and nitrogen in the form of ammonium were used as a source of nitrogen. The amount of nitrates, nitrites, ammonium, and urea in the medium was calculated from the nitrogen content of the RS nutrient medium, with a nitrogen to phosphorus ratio of 15 : 1. In the second experiment, amino acids were used as a nitrogen source – arginine, asparagine, cysteine. The possibility of using the microalgae C. closterium for the growth of various organic sources of nitrogen (urea, cysteine, asparagine) was shown. Productive characteristics in the intensive storage culture of C. closterium using urea, cysteine, and asparagine as the sole source of nitrogen in the RS nutrient medium were determined. It is shown that when urea was used, the productivity reached its maximum values and amounted to 1.5 g·l-1·day-1. Thus, the expediency of using urea in the medium for obtaining the maximum yield of biomass was shown. The use of cysteine in the stationary phase of growth to achieve a long stationary phase with minimal concentrations of the nitrogen source in the nutrient medium is also advisable. It was found that C. closterium was able to grow and vegetate at sufficiently high concentrations of nitrite, and the addition of nitrogen in ammonium form to the nutrient medium during the active growth of C. closterium led to inhibition of all metabolic processes and to the death of the culture.

Symbiotic bacteria of helminths: what role may they play in ecosystems under anthropogenic stress?

2016 ◽  
Vol 90 (6) ◽  
pp. 647-657 ◽  
Author(s):  
N.J. Morley
Keyword(s):  
Climate Change ◽  
Environmental Stress ◽  
Bacterial Communities ◽  
Bacterial Species ◽  
Symbiotic Bacteria ◽  
Anthropogenic Pressure ◽  
Anthropogenic Stress ◽  
Similar Function ◽  
Free Living ◽  
Terrestrial Habitats

AbstractSymbiotic bacteria are a common feature of many animals, particularly invertebrates, from both aquatic and terrestrial habitats. These bacteria have increasingly been recognized as performing an important role in maintaining invertebrate health. Both ecto- and endoparasitic helminths have also been found to harbour a range of bacterial species which provide a similar function. The part symbiotic bacteria play in sustaining homeostasis of free-living invertebrates exposed to anthropogenic pressure (climate change, pollution), and the consequences to invertebrate populations when their symbionts succumb to poor environmental conditions, are increasingly important areas of research. Helminths are also susceptible to environmental stress and their symbiotic bacteria may be a key aspect of their responses to deteriorating conditions. This article summarizes the ecophysiological relationship helminths have with symbiotic bacteria and the role they play in maintaining a healthy parasite and the relevance of specific changes that occur in free-living invertebrate–bacteria interactions under anthropogenic pressure to helminths and their bacterial communities. It also discusses the importance of understanding the mechanistic sensitivity of helminth–bacteria relationships to environmental stress for comprehending the responses of parasites to challenging conditions.

Interactions between Treponema bryantii and cellulolytic bacteria in the in vitro degradation of straw cellulose

1987 ◽  
Vol 33 (3) ◽  
pp. 244-248 ◽  
Author(s):  
H. Kudo ◽  
K.-J. Cheng ◽  
J. W. Costerton
Keyword(s):  
Plant Cell Wall ◽  
Bacterial Species ◽  
Barley Straw ◽  
Cellulolytic Bacteria ◽  
Morphological Examination ◽  
Cellulose Digestion ◽  
Acid Generation ◽  
Pure Cultures ◽  
Treponema Bryantii

To assess the contribution of individual bacterial species to the overall process of cellulose digestion in the rumen, cellulolytic bacteria (Bacteroides succinogenes and Ruminococcus albus) were tested as pure cultures and as cocultures with noncellulolytic Treponema bryantii. In studies of in vitro barley straw digestion, Treponema cocultures surpassed pure cultures of the cellulolytic organisms in dry matter disappearance, volatile fatty acid generation, and in the production of succinic acid, lactic acid, and ethanol. Morphological examination, by electron microscopy, showed that cells of T. bryantii associate with the plant cell wall materials in straw, but that cellulose digestion occurs only when these organisms are present with cellulolytic species such as B. succinogenes. These results show that cellulolytic bacteria interact with noncellulolytic Treponema to promote the digestion of cellulosic materials.

scholarly journals Diversity of Aerobic Bacteria Isolated from Oral and Cloacal Cavities from Free-Living Snakes Species in Costa Rica Rainforest

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Allan Artavia-León ◽  
Ariel Romero-Guerrero ◽  
Carolina Sancho-Blanco ◽  
Norman Rojas ◽  
Rodolfo Umaña-Castro
Keyword(s):  
Costa Rica ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Ribosomal Database Project ◽  
Opportunistic Pathogens ◽  
Bacterial Taxonomy ◽  
Free Living ◽  
16S Rdna Pcr ◽  
Animal Bites ◽  
Species Specific

Costa Rica has a significant number of snakebites per year and bacterial infections are often complications in these animal bites. Hereby, this study aims to identify, characterize, and report the diversity of the bacterial community in the oral and cloacal cavities of venomous and nonvenomous snakes found in wildlife in Costa Rica. The snakes where captured by casual encounter search between August and November of 2014 in the Quebrada González sector, in Braulio Carrillo National Park. A total of 120 swabs, oral and cloacal, were taken from 16 individuals of the Viperidae and Colubridae families. Samples were cultured on four different media at room temperature. Once isolated in pure culture, colonies were identified with the VITEK® 2C platform (bioMérieux). In order to test the identification provided on environmental isolates, molecular analyses were conducted on 27 isolates of different bacterial species. Specific 16S rDNA PCR-mediated amplification for bacterial taxonomy was performed, then sequenced, and compared with sequences of Ribosomal Database Project (RDP). From 90 bacterial isolates, 40 different bacterial species were identified from both oral and cloacal swabs. These results indicate the diversity of opportunistic pathogens present and their potential to generate infections and zoonosis in humans.

scholarly journals Molecular Basis of a Bacterial Consortium: Interspecies Catabolism of Atrazine

1998 ◽  
Vol 64 (1) ◽  
pp. 178-184 ◽  
Author(s):  
Mervyn L. de Souza ◽  
David Newcombe ◽  
Sam Alvey ◽  
David E. Crowley ◽  
Anthony Hay ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Southern Hybridization ◽  
Cyanuric Acid ◽  
Bacterial Species ◽  
Bacterial Consortium ◽  
Triazine Ring ◽  
Carbon And Nitrogen ◽  
Consortium Member ◽  
Ring Compounds ◽  
Pure Cultures

ABSTRACT Pseudomonas sp. strain ADP contains the genes,atzA, -B, and -C, that encode three enzymes which metabolize atrazine to cyanuric acid. Atrazine-catabolizing pure cultures isolated from around the world contain genes homologous to atzA, -B, and -C. The present study was conducted to determine whether the same genes are present in an atrazine-catabolizing bacterial consortium and how the genes and metabolism are subdivided among member species. The consortium contained four or more bacterial species, but two members, Clavibacter michiganese ATZ1 andPseudomonas sp. strain CN1, collectively mineralized atrazine. C. michiganese ATZ1 released chloride from atrazine, produced hydroxyatrazine, and contained a homolog to theatzA gene that encoded atrazine chlorohydrolase. C. michiganese ATZ1 stoichiometrically metabolized hydroxyatrazine to N-ethylammelide and contained genes homologous toatzB and atzC, suggesting that either a functional AtzB or -C catalyzed N-isopropylamine release from hydroxyatrazine. C. michiganese ATZ1 grew on isopropylamine as its sole carbon and nitrogen source, explaining the ability of the consortium to use atrazine as the sole carbon and nitrogen source. A second consortium member, Pseudomonassp. strain CN1, metabolized the N-ethylammelide produced byC. michiganese ATZ1 to transiently form cyanuric acid, a reaction catalyzed by AtzC. A gene homologous to the atzCgene of Pseudomonas sp. strain ADP was present, as demonstrated by Southern hybridization and PCR. Pseudomonassp. strain CN1, but not C. michiganese, metabolized cyanuric acid. The consortium metabolized atrazine faster than didC. michiganese individually. Additionally, the consortium metabolized a much broader set of triazine ring compounds than did previously described pure cultures in which the atzABCgenes had been identified. These data begin to elucidate the genetic and metabolic bases of catabolism by multimember consortia.

Latitudinal trends in the responses of growth respiration and maintenance respiration to temperature in the beach pea, Lathyrus japonicus

1980 ◽  
Vol 58 (14) ◽  
pp. 1521-1524 ◽  
Author(s):  
M. J. Lechowicz ◽  
L. E. Hellens ◽  
J.-P. Simon
Keyword(s):  
Respiratory Activity ◽  
Dark Respiration ◽  
Adaptive Significance ◽  
Carbon Loss ◽  
Maintenance Respiration ◽  
Growth Respiration ◽  
Beach Pea ◽  
Respiratory Responses

The response of dark respiration to temperature was measured for populations of Lathyrus japonicus collected from 39–56° N latitude. Carbon loss in dark respiration increases with latitude at all temperatures. This increased respiratory activity is attributable to concomitant increases in both the growth and maintenance components of total dark respiration. The possible adaptive significance of these respiratory responses is discussed.

scholarly journals Recent advances in the characterization of Crl, the unconventional activator of the stress sigma factor σS/RpoS

2016 ◽  
Vol 7 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Paola Cavaliere ◽  
Françoise Norel
Keyword(s):  
Transcription Initiation ◽  
Current Knowledge ◽  
Bacterial Species ◽  
Adaptive Responses ◽  
Active Growth ◽  
Recent Advances ◽  
Serovar Typhimurium ◽  
Σ Factor ◽  
And Function

AbstractThe bacterial RNA polymerase (RNAP) holoenzyme is a multisubunit core enzyme associated with a σ factor that is required for promoter-specific transcription initiation. Besides a primary σ responsible for most of the gene expression during active growth, bacteria contain alternative σ factors that control adaptive responses. A recurring strategy in the control of σ factor activity is their sequestration by anti-sigma factors that occlude the RNAP binding determinants, reducing their activity. In contrast, the unconventional transcription factor Crl binds specifically to the alternative σ factor σS/RpoS, and favors its association with the core RNAP, thereby increasing its activity. σS is the master regulator of the general stress response that protects many Gram-negative bacteria from several harmful environmental conditions. It is also required for biofilm formation and virulence of Salmonella enterica serovar Typhimurium. In this report, we discuss current knowledge on the regulation and function of Crl in Salmonella and Escherichia coli, two bacterial species in which Crl has been studied. We review recent advances in the structural characterization of the Crl-σS interaction that have led to a better understanding of this unusual mechanism of σ regulation.

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