Biodegradation of two organic UV-Filters by single bacteria strains

Organic UV-filters, including 4-hydroxybenzophenone (4-HBP) and 2,4-dihydroxybenzophenone (BP-1), are persistent emerging contaminants whose presence in the environment poses a threat to aquatic organisms due to their endocrine disruptor’s properties. For this reason, finding suitable technological processes for their safety and efficient removal from the environment represent a priority for the scientific community. To the author’s knowledge, until now, there are no studies reporting the biodegradation of 4-HBP and BP-1 by a single bacteria strain. In this paper, there were tested the 4-HBP and BP-1 biodegradation potential of two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative (Salmonella typhimurium and Serratia rubidae). The 4-HPB biodegradation process was observed only in the presence of Gram-negative bacterial strains. Thus, the biodegradation rates of 4-HBP reached up to 12.7% after 24h of incubation in presence of Salmonella thyphimurium and up to 24.0% after 24h of incubation with Serratia rubidae. Staphylococcus aureus was able to biodegrade 26.7% of BP-1, while Salmonella thiphymurium was able to biodegrade 14.7% of BP-1 after 24h of incubation. Their biodegradation products generated during the 4-HBP biodegradation process by Serratia rubidae were analyzed through LC-MS/MS analysis. The (bio)degradation products were benzophenone and a multi-hydroxylated derivative of 4-HBP and the degradation pathways were proposed. The data obtained in this study gave important information regarding the 4-HBP and BP-1 potential biodegradation by single bacterial strains.

Discovery of Substituted (2-Aminooxazol-4-yl)Isoxazole-3-carboxylic Acids as Inhibitors of Bacterial Serine Acetyltransferase in the Quest for Novel Potential Antibacterial Adjuvants

Many bacteria and actinomycetales use L-cysteine biosynthesis to increase their tolerance to antibacterial treatment and establish a long-lasting infection. In turn, this might lead to the onset of antimicrobial resistance that currently represents one of the most menacing threats to public health worldwide. The biosynthetic machinery required to synthesise L-cysteine is absent in mammals; therefore, its exploitation as a drug target is particularly promising. In this article, we report a series of inhibitors of Salmonella thyphimurium serine acetyltransferase (SAT), the enzyme that catalyzes the rate-limiting step of L-cysteine biosynthesis. The development of such inhibitors started with the virtual screening of an in-house library of compounds that led to the selection of seven structurally unrelated hit derivatives. A set of molecules structurally related to hit compound 5, coming either from the original library or from medicinal chemistry efforts, were tested to determine a preliminary structure–activity relationship and, especially, to improve the inhibitory potency of the derivatives, that was indeed ameliorated by several folds compared to hit compound 5 Despite these progresses, at this stage, the most promising compound failed to interfere with bacterial growth when tested on a Gram-negative model organism, anticipating the need for further research efforts.

Thymus vulgaris L. Essential Oil Solid Formulation: Chemical Profile and Spasmolytic and Antimicrobial Effects

A new Thymus vulgaris L. solid essential oil (SEO) formulation composed of liquid EO linked to solid excipients has been chemically analysed and evaluated for its intestinal spasmolytic and antispastic effects in ex vivo ileum and colon of guinea pig and compared with liquid EO and excipients. Liquid EO and solid linked EO were analysed by original capillary electrochromatography coupled to diode array detection (CEC-DAD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodologies. The main bioactive constituents are thymol and carvacrol, with minor constituents for a total of 12 selected analysed compounds. Liquid EO was the most effective in decreasing basal contractility in ileum and colon; excipients addiction permitted normal contractility pattern in solid linked EO SEO. In ileum and colon, the Thymus vulgaris L. solid formulation exerted the relaxant activity on K+-depolarized intestinal smooth muscle as well as liquid EO. The solid essential oil exhibits antimicrobial activity against different strains (Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli, Salmonella Thyphimurium, Candida albicans) similarly to liquid oil, with activity against pathogen, but not commensal strains (Bifidobacterium Breve, Lactobacillus Fermentum) in intestinal homeostasis. Therefore, Thymus vulgaris L. solid essential oil formulation can be proposed as a possible spasmolytic and antispastic tool in medicine.

PERFIL FITOQUÍMICO, SUSCEPTIBILIDADE ANTIBACTERIANA E CAPACIDADE ANTIOXIDANTE DAS FOLHAS DE Croton urucurana Baillon (Euphorbiaceae)

Croton urucurana Baillon, espécie conhecida popularmente como “sangria d’água”, pertence à família Euphorbiaceae, possui grande importância na medicina popular, a qual lhe atribui propriedades antibacterianas, anti-inflamatórias, antissépticas, antivirais, antidiarreicas, antissecretória intestinal e cicatrizante. Os objetivos deste estudo foram verificar a presença, nos extratos aquoso, etanólico e hidroalcoólico, de metabolitos secundários (alcaloides, antraquinonas, esteroides/triterpenoides, flavonoides, glicosídeos, saponinas e taninos), analisar a inibição do crescimento das bactérias Staphylococcus aureus ATCC 25923 e Salmonella thyphimurium ATCC 14028, e verificar a atividade antioxidante através do método DPPH. Para o perfil fitoquímico o melhor extrato foi o aquoso, quanto à susceptibilidade bacteriana, houve inibição com o extrato etanólico e o extrato com a maior atividade antioxidante foi o hidroalcóolico, apresentando IC50 1,3 μg/mL. Considerando os resultados obtidos no estudo, foi possível concluir que os extratos da Croton urucurana Baillon apresentam resultados interessantes e que mais investigações devem ser realizadas para a elucidação aprimorada dos seus benefícios.

Investigation of Mutagenic Effects of Synthetic Acidic Textile Dyes by Umu-Test (Salmonella thyphimurium TA1535/pSK1002)-a Short Term Bacterial Assay

<p class="1Body">In this study, genotoxic properties of some synthetic acidic dyes were researched by <em>umu</em>-test (<em>Salmonella thyphimurium </em>TA1535/pSK1002) which is a short term bacterial test. The study analyzed genetoxic activity of Acid Blue 127, Acid Orange 51, Acid Black 63, Acid Yellow 17 and Acid Blue 113 synthetic acidic dyes in presence and absence of S9 fraction used in Textile industry. Solutions of dyes at concentrations of 400 µg/ml, 120 µg/ml, 40 µg/ml and 4 µg/ml were prepared; and biotransformation effects of dyes that undergo chemical modifications on organisms were examined by measuring betagalactosidase activity in presence of liver enzymes by using rat S9 fraction. At the mentioned concentrations the absorbance values of betagalactosidase activity were measured for 5 synthetic acidic dyes and none of them showed mutagenic effect either in presence or absence of S9 fraction. In addition, these results mean that these synthetic acidic dyes are not metabolized with liver enzymes.</p>

Study on sanitary microbiological properties and genotoxic properties of Darhan City soil

The world population rising very fast and it has resulted in increasing the area of polluted soil, water and air. In order to cater to the demands of the people, the rapid expansion of industries, vehicles, etc. is necessary. But all of these developments make our world, especially urban area, heavily polluted. And many kind of contaminant substances showing bad effects to human health. Our research work aimed to evaluate Darhan city soil contamination using genetoxicological studies. Genotoxicological effect of soil contaminant substances or ability to cause a mutation to living organisms was determined by Eims test and DNA damaging experiment on test strain Salmonella thyphimurium TA-100 (his G46, rfa B, bio pKm 101) and Escherichia coli (wp, uvr, pol). The result revealed that Darhan city soil samples have inhibition effect to test strain growth rate. DOI: http://dx.doi.org/10.5564/mjas.v11i2.221 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.73-76

Influence of Glassy or Rubbery State on the Antimicrobial Activity of Chitosan-gelatin Films

The aim was to study if the antimicrobial activity of chitosan incorporated into edible films based on gelatin could be affected by the molecular mobility (glassy or rubbery state) of the matrix. Films were obtained from film-forming suspensions (FFS) of bovine and salmon gelatins (7% w/w) and chitosan (0; 0.25; 0.5; 1% w/w) equilibrated at 33% y 85% of relative humidities. Antimicrobial properties against <em>Escherichia coli, Listeria monocytogenes </em>and <em>Salmonella thyphimurium </em>were determined. The results showed that both FFS and films had antimicrobial effects related to chitosan concentration. This besides depended on their glass and rubber film state, being in the initially glassy state for salmon 66% higher than bovine in comparison to the rubbery state (8%). This was mainly due to the highest moisture uptake (1.82±0.02% water absorbed/min) for glassy state. Therefore, the molecular mobility of the matrix film affected the antimicrobial activity of chitosan in chitosan-gelatin films.<br /><p><strong> </strong></p>