Effects of probiotics and antibiotics on biofilms

Experiments were conducted to study the effects of probiotics and antibiotics on 3-months old biofilms formed on three different substrates, namely glass, granite and fiberglass reinforced plastic. The variations in heterotrophic bacterial populations associated with biofilms were monitored for a period of one month after one-time application of the probiotic Biogreen (Gee Key Marine Pvt. Ltd, Chennai) at 0.2 mg lˉ¹ and the antibiotic tetracycline at 1.0 mg lˉ¹. The variations in heterotrophic bacterial populations associated with biofilms were compared with that of control to analyse the effects of probiotics and antibiotics on biofilms. The observations showed that the biofilm formation and succession in aquatic environment is substrate dependent and that the resistance to antibiotics also depends on the substrate. The probiotics did not show significant effect on biofilms.

Studies on the chemical control of psychrophilic bacterial spoilage of fish. 2 - The effect of antibiotics on the growth of psycrophilic bacteria isolated from marine fish

Among the various antibiotics tried, tetracyclines particularly chlorotetracycline (CTC), chloramphenicol and chlorostrep were found to be fairly effective at 8 and 10 p.p.m. levels. The order of sensitivity to CTC among the six genera studied was found to be Achromobacterantibiotics than species belonging to other genera. Among the resistant organisms, Achromobacter superficialis was found to be most resistant and only CTC at 10 p.p.m. level could partially inhibit this culture. The useful combinations of antibiotics for commercial application are discussed.

Use of antibiotics in the preservation of prawn

Effect of incorporating chlorotetracycline (CTC) in ice up to 5 ppm level on the keeping quality of prawns has been studied. A shelf life extension by nearly six days is obtained for the CTC-iced sample over the control. The headless prawns absorbed greater amounts of CTC than whole prawns during storage in CTC-ice. Traces of the antibiotic are found in the muscle of the CTC-iced prawns even after cooking for one hour. The cause of destruction of CTC when used for prawn preservation is discussed.

Behaviour of marine microflora towards antibiotics 1. Sensitivity towards chlortetracycline (CTC)

The sensitivity of 61 cultures of bacteria isolated from fish towards chlortetracycline (CTC) at 5 ppm and 20 ppm levels has been determined on two solid media: sea water agar (SWA) and a distilled water based medium consisting of peptone, beef extract, glucose and NaCI (PBGA). The cultures employed consisted of (i) gram-negative rods of marine origin (Achromobacter, Pseudomonas, Vibrio and Flavobacterium) and (ii) gram positive organisms (Micrococci and Corynebacterium). Depending on the inhibition zone diameter, the order of CTC sensitivity was found to be Pseudomonas

The trouble with antibiotics and pesticides is...

The paper discusses the output of the meeting on the use of chemicals in aquaculture in Asia. The effects of chemical use on cultured stocks in the farm, the immediate environment through discharges and effluents, surrounding areas, farm staff, consumers and drug resistance organisms are also discussed. It also shows how an antibiotic-resistant microorganism develops as the result of indiscriminate use of antibiotics.

Effect of antibiotics on development in vitro of hamster pronucleate ova

Antibiotics are commonly added to embryo culture media, but effects on embryo development have not been examined thoroughly. Hamster ova were used to investigate whether penicillin, streptomycin or gentamicin affect embryo development in vitro. Ova were collected 10 h post activation by spermatozoa in vivo and cultured in five treatments: 1) Control: chemically-defined medium HECM-9 with no antibiotics; 2) HECM-9 with 100 IU/mL, penicillin; 3) HECM-9 with 50 mug/mL streptomycin; 4) HECM-9 with 10 mug/mL,gentamicin and 5) HECM-9 with both 100 IU/mL penicillin and 50 mug/mL streptomycin. Individually, penicillin, streptomycin and gentamicin did not affect embryo development to the 8-cell stage at 58 h post oocyte activation, or morula/blastocyst stages, or blastocysts alone at 82 h post activation. However, when penicillin and streptomycin were both present in the culture medium the percentages of 8-cell embryos at 58 h and blastocysts at 82 h were significantly lower than the control. No antibiotic treatment improved hamster embryo development in vitro. We caution against the use of penicillin and streptomycin together for hamster embryo culture, and show that it is not necessary to include any antibiotics in embryo culture media for up to 72 h if proper sterile technique is used with an oil overlay. (C) 2000 by Elsevier Science Inc.

Isolatin [sic] the bacteria produced biactive [sic] metabolits [sic] cytotoxic compound in order to prduction [sic] anticancer substance in the coral regin [sic] the Persian Gulf (Larak Island)

In the present investigation the marine bacteria isolated from corals, sponges sea water and sediments of coral regions in the larak Island located in the Persian Gulf and were examined for ability to produce cytotoxic metabolits in order to use as an anticancer compounds. Cytotoxic effect were isolated bacteria from different samples and were examined by Artemia Cytotoxic Bioassay test, in which 4.5 percent of sea waters, 12 percent of sediments and 28 percent of marine invertebrat showed cytotoxic activity, using Brine Shrimp Bioassay test. Streptomyces S-2004 isolated from soft coral specified as Sinularia erecta had LC50=0.5mg/m1 in Brine Shrimp Bioaassay test. The streptomyces S-2004 produced cytotoxic metabolits in low nutrient condition and sea water medium after 7 days on 250 rpm shaken in vitro condition. The extract partially were semipurified. Then ethyl acetate extraction from aceton extracted of bacterial plate had cytotoxic effect (LC50=4.19ktg/m1) in Human epidermoid carcinoma of mouth cells (KB) by using neutral red assay. Morphological effects of this extract on KB cells showed turgescence, cellular blebs and apoptosis which was a proof for anticancer compounds of the extract. It is seems that streptomyces S-2004 is a new strain and could be introduced as a talented bacteria, which produced cytotoxic metabolits.

Anticancer Drug-DNA Interactions Measured Using a Photoinduced Electron-Transfer Mechanism Based on Luminescent Quantum Dots

A sensing system based on the photoinduced electron transfer of quantum dots (QDs) was designed to measure the interaction of anticancer drug and DNA, taking mitoxantrone (MTX) as a model drug. MTX adsorbed on the surface of QDs can quench the photoluminescence (PL) of QDs through the photoinduced electron-transfer process; and then the addition of DNA will bring the restoration of QDs PL intensity, as DNA can bind with MTX and remove it from QDs. Sensitive detection of MTX with the detection limit of 10 nmol L-1 and a linear detection range from 10 nmol L-1 to 4.5 mu mol L-1 was achieved. The dependence of PL intensity on DNA amount was successfully utilized to investigate the interactions between MTX and DNA. Both the binding constants and the sizes of binding site of MTX-DNA interactions were calculated based on the equations deduced for the PL recovery process. The binding constant obtained in our experiment was generally consistent with previous reports. The sensitive and speedy detection of MTX as well as the avoidance of modification or immobilization process made this system suitable and promising in the drug-DNA interaction studies.

Spectral and electrochemical detection of protonated triplex formation by a small-molecule anticancer agent

Triplex helical formation has been the focus of considerable interest because of possible applications in developing new molecular biology tools as well as therapeutic agents and the possible relevance of H-DNA structures in biology system. We report here that a small-molecule anticancer agent, coralyne, has binding preference to the less stable protonated triplex d(C+-T)(6):d(A-G)(6).d(C-T)(6) over duplex d(A-G)(6).d(C-T)(6) and shows different spectral and electrochemical characteristics when binding to triplex and duplex DNA, indicating that electrochemical technique can detect the less stable protonated triplex formation.

Physical and spectral characterization of the human cyclin A gene and its interactions with anthracycline anticancer drugs

Over expression of cyclin A in human tumors has been linked to cancer by various experimental lines of evidence. However, physical and spectral characterization of the human cyclin A gene and its interactions with anticancer drugs have not been reported. Our gene sequence analysis, singular value decomposition method and melting studies in the presence of antitumor agents, daunomycin, doxorubicin and Hoechst 33258 showed that cyclin A gene had both AT-rich and GC-rich domains. For a ligand with unknown DNA binding specificity, this gene sequence can be used to differentiate its DNA binding preference.

Daunomycin binding to detergent micelles: A model system for evaluating the hydrophobic contribution to drug-DNA interactions

The interaction of daunomycin with sodium dodecyl sulfate and Triton X-100 micelles was investigated as a model for the hydrophobic contribution to the free energy of DNA intercalation reactions. Measurements of visible absorbance, fluorescence lifetime, steady-state fluorescence emission intensity, and fluorescence anisotropy indicate that the anthraquinone ring partitions into the hydrophobic micelle interior. Fluorescence quenching experiments using both steady-state and lifetime measurements demonstrate reduced accessibility of daunomycin in sodium dodecyl sulfate micelles to the anionic quencher iodide and to the neutral quencher acrylamide. Quenching of daunomycin fluorescence by iodide in Triton X-100 micelles was similar to that seen with free daunomycin. Studies of the energetics of the interaction of daunomycin with micelles by fluorescence and absorbance titration methods and by isothermal titration calorimetry in the presence of excess micelles revealed that association with sodium dodecyl sulfate and Triton X-100 micelles is driven by a large negative enthalpy. Association of the drug with both types of micelles also has a favorable entropic contribution, which is larger in magnitude for Triton X-100 micelles than for sodium dodecyl sulfate micelles.