Synthesis of Novel Pyrazolines, Their Boron-Fluorine Complexes, and Investigation of Antibacterial, Antioxidant, and Enzyme Inhibition Activities.

New 3,5-disubstituted-2-pyrazoline derivatives (4-6), their boron-fluorine complexes (boron (3-(2'-aminophenyl),5-(2'-/3'-/4'-pyridyl)pyrazoline, BOAPPY) (7-9) and boron 1,2'-diazaflavone complex (BODAF) (11) were synthesized starting from azachalcones (1-3) to diazaflavone (10), respectively. Biological evaluation of compounds 4-9 and 11 showed remarkable antioxidant, antibacterial, and acetylcholinesterase and tyrosinase enzyme inhibition activities. All newly synthesized compounds 4-9 and 11 showed respectable antibacterial effect with minimum inhibitory concentrations in the range of 4.7-150 µg/mL.

[Investigation of the frequency and distribution of beta-lactamase genes in the clinical isolates of Acinetobacter baumannii collected from different regions of Turkey: a multicenter study]. / Türkiye'nin farkli bölgelerinden toplanan klinik Acinetobacter baumannii izolatlarinda beta-laktamaz gen sikligi ve dagiliminin arastirilmasi: Çok merkezli bir çalisma.

The diversity and distribution of TEM, SHV and CTX-M type of extended-spectrum beta-lactamases (ESBLs) are important for the treatment and control of infections. Determination of ESBL genes in clinical isolates by polymerase chain reaction (PCR) and DNA sequencing can obtain useful data for their molecular epidemiology and risk. The aim of this study was to investigate the frequency of beta-lactamase genes in Acinetobacter baumannii strains isolated from different regions of Turkey. A total of 519 A.baumannii strains collected from hospitals located at 12 different provinces of Turkey (Bolu (n= 67), Tokat (n= 47), Trabzon (n= 25), Ordu (n= 27), Diyarbakir (n= 47), Nigde (n=31), Kayseri (n= 36), Ankara (n= 41), Kirikkale (n= 26), Kahramanmaras (n= 25), Mersin (n= 40), Istanbul (n= 107)] between 2011-2012 period were included in the study. Identification of the isolates were performed by both conventional methods and automated systems, VITEK2 Compact (BioMerieux, France) and API 32GN (BioMerieux, France). Disc diffusion method was used for the detection of antibiotic susceptibilities of the isolates and the results were evaluated according to CLSI (Clinical and Laboratory Standards Institute) criteria. Tigecycline and colistin sensitivities of the isolates were evaluated according to BSAC (British Society for Antimicrobial Chemotherapy) criteria. The presence of beta-lactamase genes, namely blaoxa-51, blaTEM, blaSHV, blaCTX-M1, blaCTX-M2, blaGES and blaVIM were detected by PCR. In our study, the resistance rates against colistin, tigecycline, ampicillin-sulbactam, amoxicillin-clavulanic acid, cefoperazone/sulbactam, tobramycin, ceftriaxone, piperacillin-tazobactam, gentamicin, ampicillin, tetracycline, cefepime, piperacillin, amikacin, trimethoprim-sulfamethoxazole, meropenem, levofloxacin, ciprofloxacin, imipenem and ceftazidime were detected as; 0.6%, 2.7%, 11.9%, 15.2%, 21%, 22.9%, 23.9%, 48.6%, 59.5%, 61.8%, 66.3%, 67.8%, 69.2%, 71.1%, 77.5%, 78.6%, 81.1%, 82.9%, 87.5% and 89.4%, respectively. All of the isolates (100%) were OXA-51 positive, while 443 (85.4%) out of 519 strains harbored other beta-lactamase genes searched in the study. When the distribution of the genes were evaluated, blaTEM-1 was found as the predominant one with a frequency rate of 55.7% (n=289/519), followed by blaCTX-M2 (63/519, 12.1%), blaCTX-M1 (42/519, 8.1%), blaSHV (40/519, 7.7%), blaGES (8/519, 1.5%) and blaVIM (1/519, 0.2%). Cooccurence of ESBL genes was detected in 16.3% (72/443) of the strains, being mostly TEM+CTX-M2 (20/72, 27.8%), TEM+SHV (11/72, 15.3%) and TEM+CTX-M1 (10/72, 13.9%). In addition, it was noted that the distribution of ESBL genes between isolates showed differences according to the provinces. Accordingly, none of the strains isolated from four provinces (Bolu, Nigde, Mersin, Kahramanmaras) and from three provinces (Bolu, Kahramanmaras, Diyarbakir) harbored blaCTX-M1/M2 and blaSHV genes, respectively. The blaTEM gene was detected in isolates collected from all of the provinces, with a highest frequency in Nigde (28/31, 90.3%) and lowest in Trabzon (1/25, 4%). The presence of GES-11 type ESBLs was found only in the isolates sent from Nigde province (8/31; 25.8%). Screening of metallo-beta-lactamase VIM gene also yielded a single positive result amongst only Nigde isolates (1/31; 3.2%), and this gene was identified as VIM-5 type by DNA sequencing. This study which is the first comprehensive national research to characterize ESBLs in A.baumannii isolates by molecular methods, showed that the most prevalent ESBL type is TEM (289/519, 55.7%) amongst A.baumannii strains isolated from different regions of our country. The data of our study is parallel to the results of previous studies carried out from Turkey.

Distribution of ß-lactamase genes among carbapenem-resistant Klebsiella pneumoniae strains isolated from patients in Turkey.

BACKGROUND: The emergence of carbapenem-resistant Klebsiella pneumoniae poses a serious problem to antibiotic management. We investigated the ß-lactamases in a group of carbapenem-resistant K. pneumoniae clinical isolates from Turkey. METHODS: Thirty-seven strains of K. pneumoniae isolated from various clinical specimens were analyzed by antimicrobial susceptibility testing, PCR for the detection of ß-lactamase genes, DNA sequencing, and repetitive extragenic palindronic (REP)-PCR analysis. RESULTS: All 37 isolates were resistant to ampicillin, ampicillin/sulbactam, piperacillin, piperacillin/tazobactam, ceftazidime, cefoperazone/sulbactam, cefepime, imipenem, and meropenem. The lowest resistance rates were observed for colistin (2.7%), tigecycline (11%), and amikacin (19%). According to PCR and sequencing results, 98% (36/37) of strains carried at least one carbapenemase gene, with 32 (86%) carrying OXA-48 and 7 (19%) carrying NDM-1. No other carbapenemase genes were identified. All strains carried a CTX-M-2-like ß-lactamase, and some carried SHV- (97%), TEM- (9%), and CTX-M-1-like (62%) ß-lactamases. Sequence analysis of bla(TEM) genes identified a bla(TEM-166) with an amino acid change at position 53 (Arg53Gly) from bla(TEM-1b), the first report of a mutation in this region. REP-PCR analysis revealed that there were seven different clonal groups, and temporo-spatial links were identified within these groups. CONCLUSIONS: Combinations of ß-lactamases were found in all strains, with the most common being OXA-48, SHV, TEM, and CTX-M-type (76% of strains). We have reported, for the first time, a high prevalence of the NDM-1 (19%) carbapenemase in carbapenem-resistant K. pneumoniae from Turkey. These enzymes often co-exist with other ß-lactamases, such as TEM, SHV, and CTX-M ß-lactamases.

Synthesis, aggregation and spectroscopic studies of novel water soluble metal free, zinc, copper and magnesium phthalocyanines and investigation of their anti-bacterial properties.

In this study, novel phthalonitrile derivative (3) was synthesized by the reaction between 4-nitrophthalonitrile (2) and a triazole derivative (1) containing pyridine moiety. Crystal structure of compound (3) was characterized by X-ray diffraction. New metal free and metallo-phthalocyanine complexes (Zn, Cu, and Mg) were synthesized using the phthalonitrile derivative (3). Cationic derivatives of these phthalocyanines (5, 7, 9, and 11) were prepared from the non-ionic phthalocyanines (4, 6, 8, and 10). All proposed structures were supported by instrumental methods. The aggregation behaviors of the phthalocyanines (4-11) were investigated in different solvents such as dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), chloroform and water. Water soluble cationic Pcs (5, 7, 9, and 11) aggregated in water and sodium dodecyl sulfate was used to prevent the aggregation. The second derivatives of the UV-Vis spectra of aggregated Pcs were used for analyzing the Q and B bands of aggregated species. Thermal behaviors of the phthalocyanines were also studied. In addition, anti-bacterial properties of the phthalocyanines were investigated. We used four gram negative and two gram positive bacteria to determine antibacterial activity of these compounds. Compound 7 has the best activity against the all bacteria with 125µg/mL of MIC value. Compounds 4, 6, and 10 have the similar effect on the bacteria with 250µg/mL of MIC value.

Synthesis, antibacterial and antioxidant activities of new 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides.

New 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides (3a-k) were synthesized from 1,4'-diazaflavone [2-pyridin-4-ylquinolin-4(1H)-one] and evaluated for antibacterial and antioxidant activities. A rapid one-pot preparation of 1,4'-diazaflavone (2) was done from 2'-amino substituted chalcone (1) by intramolecular Michael addition using solvent-free microwave heating. New N,N'-dialkyl substituted (C5-C15) 1,4'-diazaflavonium bromides were synthesized from compound 2 with corresponding alkyl halides. Compounds 3a-k were active against six bacteria (MIC: 7.8-500.0 µg/mL). They also showed good antioxidant activities in DPPH scavenging (SC50: 45-133 µg/mL) and ferric reducing/antioxidant power (14-141 µM TEAC) tests. The biological activities decreased as alkyl chain length increased. The reason behind the obvious negative effect of alkyl chain elongation is unclear and requires investigations about the intermolecular interactions of these pyridinium salts with bioassay components.

The ATPase activity of the G2alt gene encoding an aluminium tolerance protein from Anoxybacillus gonensis G2.

The G2ALT gene was cloned and sequenced from the thermophilic bacterium Anoxybacillus gonensis G2. The gene is 666 bp long and encodes a protein 221 amino acids in length. The gene was overexpressed in E. coli and purified to homogeneity and biochemically characterized. The enzyme has a molecular mass of 24.5 kDa and it could be classified as a member of the family of bacterial aluminium resistance proteins based on homology searches. When this fragment was expressed in E. coli, it endowed E. coli with Al tolerance to 500 µM. The purified G2ALT protein is active at a broad pH range (pH 4.0-10.0) and temperature range (25°C-80°C) with optima of 6.0 and the apparent optimal temperature of 73°C respectively. Under optimal conditions, G2ALT exhibited a low ATPase activity with K (m) (-) and V (max) (-) values of 10±0.55 µM and 26.81±0.13 mg Pi released/min/mg enzyme, respectively. The ATPase activity of G2ALT requires Mg(2+) and Na(+) ions, while Zn(2+) and Al(3+) stimulate the activity. Cd(2+) and Ag(+) reduced the activity and Li(+), Cu(2+), and Co(2+) inhibited the activity. Known inhibitors of most ATPases, like such as ß-mercaptoethanol and ouabain, also inhibited the activity of the G2ALT. These biochemical characterizations suggested that G2ALT belongs to the PP-loop ATPase superfamily and it can be responsible for aluminium tolerance in A. gonensis G2.