Rise and Fall of Bacterial Populations in Fish Muscle

1943 ◽  
Vol 6b (2) ◽  
pp. 119-128 ◽  
Author(s):  
H. L. A. Tarr
Keyword(s):  
Bacterial Culture ◽  
Bacterial Count ◽  
Fish Muscle ◽  
Growth Phases ◽  
Bacterial Populations ◽  
Count Method ◽  
Pure Bacterial Culture ◽  
Direct Counts

A direct bacterial count method applicable to fish muscle containing over approximately 1 × 105 bacteria per gram, with a modification employing preliminary incubation for muscle containing fewer bacteria, is described. Direct counts generally yielded similar and somewhat higher results than viable counts. Mixed bacterial populations of fish muscle generally exhibited the growth phases characteristic of a pure bacterial culture. There was absolutely no relation between direct (or viable) counts obtained subsequent to such incubation and the initial viable counts of the samples studied. Bacteria increased much more rapidly in excised fish muscle than in whole fish, and somewhat more rapidly in halibut than in salmon flesh.

Seasonal variations in heterotrophic bacterial populations in waters off Sydney

1964 ◽  
Vol 15 (1) ◽  
pp. 73
Author(s):  
AD Brown
Keyword(s):  
Negative Correlation ◽  
Seasonal Variations ◽  
Bacterial Population ◽  
Heterotrophic Bacteria ◽  
Bacterial Count ◽  
Early Summer ◽  
Total Bacterial Count ◽  
Bacterial Populations ◽  
Seawater Samples

Viable counts were made of heterotrophic bacteria in seawater samples taken from 0, 25, 50, 75, and 100 m at one station off Sydney over a period of 2 years. Populations, which fell largely within the range of 10-1000/ml, tended to be higher in spring and early summer than at other times. Some evidence was obtained of a negative correlation between bacterial population and chlorinity. There was no evidence of a correlation between bacterial populations and several other variables which were examined. A (presumed) species of Chromobacterium occurred intermittently at the lower depths with some suggestion of a correlation with season and total bacterial count.

scholarly journals Magnesium Links Starvation-Mediated Antibiotic Persistence to ATP

mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Tao Xu ◽  
Xuyang Wang ◽  
Lu Meng ◽  
Mengqi Zhu ◽  
Jing Wu ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Bacterial Culture ◽  
Marker Genes ◽  
Cell Marker ◽  
Growth Phases ◽  
Content Type ◽  
Underlying Basis ◽  
Over Time ◽  
Stationary Cell

ABSTRACT Bacterial persisters emerge and increase in numbers over time as a bacterial culture grows from log phase to stationary phase. However, the underlying basis of the inevitable tendency is unclear. In this study, we investigated the role of nutrients in starvation-mediated persister formation of Staphylococcus aureus. By screening of nutrient components, we found that starvation-induced persister formation of log-phase cultures could be reversed by addition of magnesium (Mg2+) but not amino acids, nucleotides, or other salts. Further, deprivation of extracellular Mg2+ reduced cytoplasmic ATP, inducing persistence without affecting cytoplasmic Mg2+ or membrane potential. Finally, we showed that Mg2+ reduced expression of stationary cell marker genes, cap5A and arcA. These findings indicate a connection between Mg2+ levels and ATP, which represents metabolic status and mediates antibiotic persistence during growth. IMPORTANCE Various genes have been identified to be involved in bacterial persister formation regardless of the presence or absence of persister genes. Despite recent discoveries of the roles of ATP and membrane potential in persister formation, the key element that triggers change of ATP or membrane potential remains elusive. Our work demonstrates that Mg2+ instead of other ions or nutrient components is the key element for persistence by inducing a decrease of cytoplasmic ATP, which subsequently induces persister formation. In addition, we observed tight regulation of genes for Mg2+ transport in different growth phases in S. aureus. These findings indicate that despite being a key nutrient, Mg2+ also served as a key signal in persister formation during growth.

scholarly journals Biodegradation of Methyl tert-Butyl Ether by a Pure Bacterial Culture

2001 ◽  
Vol 67 (12) ◽  
pp. 5601-5607 ◽  
Author(s):  
Paul B. Hatzinger ◽  
Kevin McClay ◽  
Simon Vainberg ◽  
Marina Tugusheva ◽  
Charles W. Condee ◽  
...  
Keyword(s):  
Bacterial Culture ◽  
Butyl Alcohol ◽  
The Other ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Pure Bacterial Culture ◽  
Degradation Activity ◽  
Type Strains ◽  
Mtbe Degradation ◽  
Allyl Thiourea

ABSTRACT Biodegradation of methyl tert-butyl ether (MTBE) by the hydrogen-oxidizing bacterium Hydrogenophaga flavaENV735 was evaluated. ENV735 grew slowly on MTBE ortert-butyl alcohol (TBA) as sole sources of carbon and energy, but growth on these substrates was greatly enhanced by the addition of a small amount of yeast extract. The addition of H2 did not enhance or diminish MTBE degradation by the strain, and MTBE was only poorly degraded or not degraded by type strains of Hydrogenophaga or hydrogen-oxidizing enrichment cultures, respectively. MTBE degradation activity was constitutively expressed in ENV735 and was not greatly affected by formaldehyde, carbon monoxide, allyl thiourea, or acetylene. MTBE degradation was inhibited by 1-amino benzotriazole and butadiene monoepoxide. TBA degradation was inducible by TBA and was inhibited by formaldehyde at concentrations of >0.24 mM and by acetylene but not by the other inhibitors tested. These results demonstrate that separate, independently regulated genes encode MTBE and TBA metabolism in ENV735.

Anaerobic benzene biodegradation by a pure bacterial culture of Bacillus cereus under nitrate reducing conditions

2010 ◽  
Vol 22 (5) ◽  
pp. 709-715 ◽  
Author(s):  
Junfeng Dou ◽  
Aizhong Ding ◽  
Xiang Liu ◽  
Yongchao Du ◽  
Dong Deng ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Bacterial Culture ◽  
Reducing Conditions ◽  
Pure Bacterial Culture

scholarly journals Milk hygiene in small ruminants: A review

2018 ◽  
Vol 15 (4) ◽  
pp. e05R02 ◽  
Author(s):  
Carlos Gonzalo
Keyword(s):  
Health Management ◽  
Small Ruminants ◽  
Cost Effective ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Screening Methods ◽  
Economic Returns ◽  
Water Addition ◽  
Bacterial Populations ◽  
Bacterial Counts

Somatic cell count (SCC), mammary pathogens prevalence, total and specific bacterial counts, antimicrobial residues, macroscopic sediment, water addition, aflatoxins and other contaminants constitute the basis for milk payment-schemes, monitoring and improvement of flock hygiene and health management, and development of analytical surveillance programs in the dairy small ruminants. The present work reviews factors influencing the variation of these variables, including milk analytical methods, storage and preservation, along with management implications during the last two decades. Following farmer and cooperative educational programs, progressive reductions have been reported for total bacterial count and antimicrobial residue occurrence in bulk tank milk. These results were consistent, however, with high values for SCC and specific bacterial populations. Thus, mastitis control programs should be intensified to increase hygiene in milk and economic returns for producers and processors. In addition, the implementation of programs to reduce specific bacterial counts (i.e., psychrotrophs, coliforms, Clostridium spp. spores) and mammary pathogen prevalence (i.e., Staph. aureus, Mycoplasma spp.), as well as the use of combined screening methods for an increased rate of antimicrobial detection, are currently required strategies which are positively valuated by milk processors, industry and consumers. Other contaminants may also be present, but cost-effective screening and analytical systems have not yet been implemented. This review aims to be helpful for troubleshooting milk quality and safety, developing future premium payment systems and industry quality-standards, optimizing management, on-farm risk traceability systems and consumer acceptance.

Fermentative Biohydrogen Production by Mixed and Pure Bacterial Culture: Designing of Processes and Engineering Control

Solar Energy ◽  
2005 ◽  
Author(s):  
Yong-Feng Li ◽  
Nan-Qi Ren ◽  
Li-Jie Hu ◽  
Guo-Xiang Zheng ◽  
Maryam Zadsar
Keyword(s):  
Hydrogen Production ◽  
Continuous Culture ◽  
Bacterial Culture ◽  
Production Systems ◽  
Production Engineering ◽  
Schematic Processing ◽  
Engineering Control ◽  
Pure Bacterial Culture ◽  
Technical Issues ◽  
Fermentation Parameters

In this paper the research about applied bio-hydrogen production engineering is introduced. The advantages, disadvantages and characteristics of bio-hydrogen production systems and some technical issues on anaerobic fermentative bio-hydrogen producing systems will be discussed and focused on the schematic processing, designing strategies and engineering control of fermentation parameters and also the technical means to increase the evolved hydrogen and hydrogen evolution rate. The technology of bio-hydrogen production based on ethanol-type fermentative theory has been established. The mixed continuous culture and pure batch culture processes were proposed for hydrogen production.

Evaluation of pure bacterial culture from fermented cassava as soy-yoghurt starter: a research note

1996 ◽  
Vol 29 (5-6) ◽  
pp. 549-553 ◽  
Author(s):  
L.M. Nsofor ◽  
O.N. Nsofor ◽  
C. Udegbe ◽  
E.C. Nwoke
Keyword(s):  
Bacterial Culture ◽  
Research Note ◽  
Pure Bacterial Culture
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