scholarly journals Bacterial Colonization of Particles: Growth and Interactions

2003 ◽  
Vol 69 (6) ◽  
pp. 3500-3509 ◽  
Author(s):  
Hans-Peter Grossart ◽  
Thomas Ki�rboe ◽  
Kam Tang ◽  
Helle Ploug
Keyword(s):  
Population Density ◽  
Antibiotic Production ◽  
Interspecific Interactions ◽  
Bacterial Colonization ◽  
Hydrolytic Activity ◽  
Inhibitory Effect ◽  
Colonization Rate ◽  
Small Scale ◽  
Bacterial Strains ◽  
Marine Particles

ABSTRACT Marine particles in the ocean are exposed to diverse bacterial communities, and colonization and growth of attached bacteria are important processes in the degradation and transformation of the particles. In an earlier study, we showed that the initial colonization of model particles by individual bacterial strains isolated from marine aggregates was a function of attachment and detachment. In the present study, we have investigated how this colonization process was further affected by growth and interspecific interactions among the bacteria. Long-term incubation experiments showed that growth dominated over attachment and detachment after a few hours in controlling the bacterial population density on agar particles. In the absence of grazing mortality, this growth led to an equilibrium population density consistent with the theoretical limit due to oxygen diffusion. Interspecific interaction experiments showed that the presence of some bacterial strains (“residents”) on the agar particles either increased or decreased the colonization rate of other strains (“newcomers”). Comparison between an antibiotic-producing strain and its antibiotic-free mutant showed no inhibitory effect on the newcomers due to antibiotic production. On the contrary, hydrolytic activity of the antibiotic-producing strain appeared to benefit the newcomers and enhance their colonization rate. These results show that growth- and species-specific interactions have to be taken into account to adequately describe bacterial colonization of marine particles. Changes in colonization pattern due to such small-scale processes may have profound effects on the transformation and fluxes of particulate matter in the ocean.

Preliminary in Vitro Investigations on The Inhibitory Activity of The Original Dietary Supplement Oxidal® on Pathogenic Bacterial Strains

2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov
Keyword(s):  
Dietary Supplement ◽  
Broad Spectrum ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Clinical Effectiveness ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Microbial Strains

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.

scholarly journals Synthesis and Evaluation of Biological Activity of New Arylphosphoramidates

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Amal Thebti ◽  
M. A. K. Sanhoury ◽  
H-I. Ouzari ◽  
T. Barhoumi-slimi
Keyword(s):  
Biological Activity ◽  
Ir Spectroscopy ◽  
Acetylcholinesterase Activity ◽  
Inhibitory Effect ◽  
Bacterial Strains ◽  
Significant Inhibitory Effect ◽  
Subsequent Addition

The synthesis of new substituted arylphosphoramidates is performed in two steps through phosphorylation of the corresponding alcohols followed by aminolysis. The formation of the desired phosphoramidates depends on the subsequent addition of the two alcohols with the amine being added at the last step. The products were obtained in 58–95% yields. They were characterized mainly by multinuclear (1H, 13C, 31P, and 19F) NMR and IR spectroscopy. In addition, the antimicrobial and antiacetylcholinesterase activities were evaluated. The results showed acetylcholinesterase activity by some compounds, whilst no significant inhibitory effect against the tested bacterial strains has been recorded.

scholarly journals Antibacterial activity of plant extracts against Listeria monocytogenes isolated from ready-to-eat salads

2020 ◽  
Vol 13 (1) ◽  
pp. 131-143
Author(s):  
É. György ◽  
É. Laslo ◽  
E. Csató
Keyword(s):  
Listeria Monocytogenes ◽  
Essential Oils ◽  
Antibacterial Effect ◽  
Storage Conditions ◽  
Inhibitory Effect ◽  
Listeria Innocua ◽  
Foodborne Diseases ◽  
Bacterial Strains ◽  
Antibacterial Effects ◽  
Growth Environment

Abstract Ready-to-eat salads are becoming more and more popular. However, due to their ingredients, they represent a suitable growth environment for different microbes. In the prevention of foodborne diseases, hygienic food preparation and appropriate storage conditions are very important. During this study, ten different ready-to-eat salads were analysed for the presence of Listeria monocytogenes. Five different selective agar mediums were used for the enumeration and isolation of Listeria monocytogenes. The isolated bacterial strains were subjected to morphological and biochemical confirmation tests. The antibacterial effects of five different freshly squeezed vegetable juices (carrots, celery, beets, horseradish, and onions) and of five essential oils (dill, thyme, oregano, lemongrass, and sage) were determined against Listeria monocytogenes, Listeria innocua, and L. monocytogenes strains isolated from ready-to-eat salads. Based on the results obtained from fresh vegetable juices, carrot juice exerted the highest antibacterial effect, while the others showed no or slight inhibitory effect (horseradish, beets, onions) against Listeria species. Among the essential oils, thyme, lemongrass, and oregano showed the strongest antibacterial effect against the studied Listeria species.

scholarly journals Searching for Antagonistic Activity of Bacterial Isolates Derived from Food Processing Environments on Some Food-Borne Pathogenic Bacteria

2020 ◽  
Vol 49 (4) ◽  
pp. 415-423
Author(s):  
B. Baráti-Deák ◽  
Cs. Mohácsi-Farkas ◽  
Á. Belák
Keyword(s):  
Escherichia Coli ◽  
Food Processing ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Antagonistic Activity ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Food Borne ◽  
Time Period ◽  
Growth Decline

Bacterial strains with inhibitory effect on Salmonella Hartford, Listeria monocytogenes, Yersinia enterocolitica, and Escherichia coli, respectively, were isolated. Out of the 64 bacteria originated from food processing environments, 20 could inhibit at least one of the tested pathogens, and it was proved that growth decline of the pathogenic bacteria was more remarkable by co-culturing than by using cell-free supernatants of the isolates. Seven different genera (Pseudomonas, Bacillus, Paenibacillus, Macrococcus, Staphylococcus, Serratia, and Rothia) reduced the pathogens’ growth during the time period of analysis, and the strongest inhibitory effect was observed after 24 h between 15 and 30 °C. Sensitivity of the tested human pathogenic bacteria against the inhibitory strains was distinct, as Y. enterocolitica could be inhibited by numerous isolates, while S. Hartford proved to be the most resistant. Our results reveal that the isolated bacteria or their excreted metabolites could hinder pathogen growth when used in sufficient quantities.

scholarly journals Effect of Disturbance Regimes on Spatial Patterns of Tree Species in Three Sites in a Tropical Evergreen Forest in Vietnam

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Do Thi Ngoc Le ◽  
Nguyen Van Thinh ◽  
Nguyen The Dung ◽  
Ralph Mitlöhner
Keyword(s):  
Spatial Patterns ◽  
Tree Species ◽  
Interspecific Interactions ◽  
Abundant Species ◽  
Evergreen Forest ◽  
Small Scale ◽  
Forest Types ◽  
Disturbance Regimes ◽  
Tropical Evergreen Forest ◽  
Disturbed Forest

The effects of disturbance regimes on the spatial patterns of the five most abundant species were investigated in three sites in a tropical forest at Xuan Nha Nature Reserve, Vietnam. Three permanent one-ha plots were established in undisturbed forest (UDF), lightly disturbed forest (LDF), and highly disturbed forest (HDF). All trees ≥5 cm DBH were measured in twenty-five 20 m × 20 m subplots. A total of 57 tree species belonging to 26 families were identified in the three forest types. The UDF had the highest basal area (30 m2 ha−1), followed by the LDF (17 m2 ha−1) and the HDF (13.0 m2 ha−1). The UDF also had the highest tree density (751 individuals ha−1) while the HDF held the lowest (478 individuals ha−1). Across all species, there were 417 “juveniles,” 267 “subadults,” and 67 “adults” in the UDF, while 274 “juveniles,” 230 “subadults,” and 36 “adults” were recorded in the LDF. 238 “juveniles,” 227 “subadults,” and 13 “adults” were obtained in the HDF. The univariate and bivariate data with pair- and mark-correlation functions of intra- and interspecific interactions of the five most abundant species changed in the three forest types. Most species indicated clumping or regular distributions at small scale, but a high ratio of negative interspecific small-scale associations was recorded in both the LDF and HDF sites. These were, however, rare in the UDF.

Autoinducer-2–like Activity in Lactic Acid Bacteria Isolated from Minced Beef Packaged under Modified Atmospheres

2011 ◽  
Vol 74 (4) ◽  
pp. 631-635 ◽  
Author(s):  
VASILIKI A. BLANA ◽  
AGAPI I. DOULGERAKI ◽  
GEORGE-JOHN E. NYCHAS
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Storage Temperature ◽  
Inhibitory Effect ◽  
Bacterial Strains ◽  
Modified Atmospheres ◽  
Autoinducer 2 ◽  
Meat Spoilage ◽  
Minced Beef ◽  
Biosensor Strain

Fifteen fingerprints (assigned to Leuconostoc spp., Leuconostoc mesenteroides, Weissella viridescens, Leuconostoc citreum, and Lactobacillus sakei) of 89 lactic acid bacteria (LAB) isolated from minced beef stored under modified atmospheres at various temperatures were screened for their ability to exhibit autoinducer-2 (AI-2)–like activity under certain growth conditions. Cell-free meat extracts (CFME) were collected at the same time as the LAB isolates and tested for the presence of AI-2–like molecules. All bioassays were conducted using the Vibrio harveyi BAA-1117 (sensor 1−, sensor 2+) biosensor strain. The possible inhibitory effect of meat extracts on the activity of the biosensor strain was also evaluated. AI-2–like activity was observed for Leuconostoc spp. isolates, but none of the L. sakei strains produced detectable AI-2–like activity. The AI-2–like activity was evident mainly associated with the Leuconostoc sp. B 233 strain, which was the dominant isolate recovered from storage at 10 and 15°C and at the initial and middle stages of storage at chill temperatures (0 and 5°C). The tested CFME samples displayed low AI-2–like activity and inhibited AI-2 activity regardless of the indigenous bacterial populations. The LAB isolated during meat spoilage exhibited AI-2–like activity, whereas the LAB strains retrieved depended on storage time and temperature. The production of AI-2–like molecules may affect the dominance of different bacterial strains during storage. The results provide a basis for further research concerning the effect of storage temperature on the expression of genes encoding AI-2 activity and on the diversity of the ephemeral bacterial population.

Antimicrobial effects of the phenolic compounds of Mentha piperita L on Streptococcus thermophilus and Lactobacillus bulgaricus and impacts on the quality of an alicament steamed yoghurt

2022 ◽  
Vol 11 (6) ◽  
pp. 646-666
Author(s):  
Ouiza Ait Chabane ◽  
Djamal Ait Saada ◽  
Sara Bensoula ◽  
Mouna Moulay ◽  
Ismahene Ghomri ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Streptococcus Thermophilus ◽  
Fermented Milk ◽  
Inhibitory Effect ◽  
Lactobacillus Bulgaricus ◽  
Mentha Piperita ◽  
Total Phenolic ◽  
Bacterial Strains ◽  
Hydroethanolic Extract

This study contributes to the evaluation of the antibacterial effect of hy-droethanolic extract of peppermint (Mentha piperita L.) rich in phenolic compounds on the growth of reference bacterial strains Streptococcus ther-mophilus (ATCC19258) and Lactobacillus bulgaricus (ATCC11842) as well as the consequences of its addition at a dose of 6% on the quality of a steamed yoghurt. The phenolic compounds of peppermint collected in Algeria were extracted from the ground leaves of the plant in a hydroethanolic solution. The antimicrobial activity of peppermint extract and the quality of yoghurt were assessed by the following measures: bacterial growth test, disc diffu-sion test, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), pH, acidity, viscosity and the organoleptic tests (taste, odor, color and freshness). The results revealed that hydroethanolic extract of M. piperita L. had 25 mg GAE/ml of extract of total phenolic compound and a content of 8.28 mg QE/ml of extract of flavonoids. This extract had a bactericidal against S. thermophilus and a bacteriostatic inhibitory effect against L. bulgaricus. The addition of phenolic compounds of M. piperita L. at 154.02 mg GAE/100ml significantly reduced (p<0.05) acidity, viscosity, and the germ increase of S. thermophilus and L. bulgaricus in steamed yogurt prepared with 6% of hydroethanolic extract of the studied plant compared to the control. However, the fermented milk treated with the 6% of pepper-mint extract was very well appreciated by the tasting jury, just like the yo-ghurt control.

Inhibitory Effect of Caffeine on Growth of Various Bacterial Strains

2008 ◽  
Vol 3 (6) ◽  
pp. 457-465 ◽  
Author(s):  
Sathyanarayana N. Gummadi ◽  
Swati Sucharita Dash
Keyword(s):  
Inhibitory Effect ◽  
Bacterial Strains

scholarly journals In Vitro Evaluation of Gentamicin or Vancomycin Containing Bone Graft Substitute in the Prevention of Orthopedic Implant-Related Infections

2020 ◽  
Vol 21 (23) ◽  
pp. 9250
Author(s):  
Alessandro Bidossi ◽  
Marta Bottagisio ◽  
Nicola Logoluso ◽  
Elena De Vecchi
Keyword(s):  
Antibiotic Resistance ◽  
Bone Graft ◽  
Calcium Sulfate ◽  
Prolonged Exposure ◽  
Bacterial Colonization ◽  
Bone Graft Substitute ◽  
Bacterial Strains ◽  
Bone Graft Substitutes ◽  
Biofilm Development

Antibiotic-loaded bone graft substitutes are attractive clinical options and have been used for years either for prophylaxis or therapy for periprosthetic and fracture-related infections. Calcium sulfate and hydroxyapatite can be combined in an injectable and moldable bone graft substitute that provides dead space management with local release of high concentrations of antibiotics in a one-stage approach. With the aim to test preventive strategies against bone infections, a commercial hydroxyapatite/calcium sulfate bone graft substitute containing either gentamicin or vancomycin was tested against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, harboring different resistance determinants. The prevention of bacterial colonization and biofilm development by selected microorganisms was investigated along with the capability of the eluted antibiotics to select for antibiotic resistance. The addition of antibiotics drastically affected the ability of the selected strains to adhere to the tested compound. Furthermore, both the antibiotics eluted by the bone graft substitutes were able to negatively impair the biofilm maturation of all the staphylococcal strains. As expected, P. aeruginosa was significantly affected only by the gentamicin containing bone graft substitutes. Finally, the prolonged exposure to antibiotic-containing sulfate/hydroxyapatite discs did not lead to any stable or transient adaptations in either of the tested bacterial strains. No signs of the development of antibiotic resistance were found, which confirms the safety of this strategy for the prevention of infection in orthopedic surgery.

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