In this paper, 2-hydroxyethyl methacrylate (HEMA) was graft copolymerized onto chitosan (CHI) at different ratios using a radical initiator. The grafted hydrogel composites were then characterized by attenuated total reflection Fourier transform ınfrared spectroscopy (ATR-FTIR) and thermo-gravimetric analysis (TGA). Swelling behavior of the hydrogels was investigated at different pH and different times. The antimicrobial activity of the chitosan-graft-HEMA (CHI-HEMA) against gram-negative bacteria and gram-positive bacteria was studied by the standard agar well diffusion assay method. The CHI-HEMA 1:1 and CHI-HEMA 1:2 showed an obvious antimicrobial effect against six test strains. The CHI-HEMA 1:1 and CHI-HEMA 1:2 exhibited a highly significant increase (p < 0.01) in diameter of the inhibition zones compared with the standard antibiotics. Furthermore, CHI-HEMA 1:1 presented the highest antimicrobial activity against all test strains with a significant difference (p < 0.01) compared with CHI-HEMA 1:2. Meanwhile, the decreasing order of the average sensitivity to CHI-HEMA 1:1 and CHI-HEMA 1:2 was observed to be S. marcescens > E. coli > S. aureus subsp. aureus > S. enteritidis > E. faecalis > E. aerogenes. These results indicate potential application of CHI-HEMA 1:1 and CHI-HEMA 1:2 graft hydrogels as a novel and efficient antimicrobial agent in biomedical fields.

Extracellular and cell-associated enzyme preparations were obtained from ruminal anaerobic fungi Orpinomyces sp. GMLF5 grown in culture containing microcrystalline cellulose (avicel) as sole energy source and degradation capacities of the preparations towards several polysaccharides and glycosides were studied. Fungus showed substantial increases in xylanase, carboxymethyl cellulase (CMCase), lichenase, amylase, beta-xylosidase, beta-glucosidase and alpha-L-arabinofuranosidase activities between 72 and 168 hours. High amounts of cell associated beta-xylosidase were noted in 4 and 5 days old cultures. Optimum temperature and pH of the polysaccharidases were found at 50 degrees C and 6.0-6.5, respectively. Xylanase was found to be virtually stable at 50 degrees C, CMCase and lichenase were stable at 40 degrees C for 200 min, however amylase was found more sensitive to heat treatment. The fibrolytic enzymes of the isolate GMLF5 were observed to be capable of hydrolyze the avicel.

Bu çalışmada kitosan (KT) ve polivinil alkol (PA) karışımına %0, %0.5, %1 ve %2 oranlarında 3-(aminopropil) trimetoksi silan (3-APTMS) ilave edilerek dökme metoduyla filmler hazırlanmıştır. Hazırlanan filmlerin FTIR, SEM, su buharı geçirgenliği, çözünürlük, opaklık ve renk özellikleri incelenmiştir. KT/PA, KT/PA-0.5, KT/PA-1 ve KT/PA-2 filmlerinin su buharı geçirgenliği sırasıyla 3.82×10-6 g m-1 s-1 Pa-1, 3.14×10-6 g m-1 s-1 Pa-1, 2.08×10-6 g m-1 s-1 Pa-1 ve 1.59×10-6 g m-1 s-1 Pa-1 olarak gerçekleşti. Filmleri su içinde çözünürlüğü azaldı. Artan 3-APTMS içeriği ile filmler daha opak oldu ve UV ışık bariyer özellik gösterdi. Renk özellikleri ise a* değeri artarken b* değeri ise azalarak filmler sarımsı-yeşil oldu. Ayrıca filmlerin Gram negatif (E. coli ) ve gram pozitif (S. aureus subsp. aureus) bakterilere karşı antimikrobiyal aktiviteleri değerlendirildi. Elde edilen KT/PA tek başına S. aureus subsp. aureus (ATCC 25923) ve E. coli (ATCC 25922) ye karşı herhangi bir antimikrobiyal aktiviteyi göstermedi. Dikkat çeken nokta KT/PA'ya eklenen %2 3-APTMS antibakteriyel aktivitenin standart olarak kullanılan ampisilin ile aynı olmasıdır.

No abstract

Lactic acid bacteria (LAB) are group of commercially important organisms that play an important role in the fermentation process of hexose sugars into lactic acid and they are videly used in dairy industrial applications since they were designated as "generally recognised as safe" organisms. In order to isolate laktic acid bacteria (LAB), forty fermented food samples were collected and 160 bacterial strains were purified and identified from those samples. According to morphological characteristics, 62 isolates (38.75%) were classified as cocci and all these cocci were found to be as catalase negative and grown well on MRS agar plates. Coccobacilli and bacilli forms were observed in 66 (41.25%) and 19 (11.875%) isolates respectively. Total of 13 isolates (8.125%) were classified as "others" (according to morphological characteristics) and excluded from rest of experimental process. For molecular identification of Leuconostoc sp. and Pediococcus sp., 16S and 23S rDNAs (respectively) were amplified with the aid of PCR and 34 of them were classified as Pediococcus whilst 4 of them were designated as Leuconostoc. These newly isolated strains were tested for their antimicrobial activity and more than one strains exhibited antimicrobial activity against to S. paratyphi and E. faecali. All tested strains showed relatively lower (≤ 10mm in diameter) antimicrobial effect against P. mirabilis, E. coli and C. jejuni while P. aeruginosa showed resistancy against all bacteriocins produced tested isolates. Result of this study revealed that majority of the tested (n=20) isolates were resistant to erythromycin, chloramphenicol and rifampin. All isolates were investigated for the presence of plasmid vectors and 10 of them found having at least 1 plasmid vector.

In this present study, composites of chitosan‐graft‐poly(N‐tertiary butylacrylamide) (CH‐graft‐poly(N‑tert‑BAAm)) copolymer, with Neodymium (Nd), an important rare earth element, were prepared by precipitation technique. Nd was successfully incorporated into the polymer of different weight percentages (0.5%, 1%, and 2%) without any degradation. The effect of neodymium additives on the structural, morphological, and antibacterial activities against gram‐positive bacteria and gram‐negative bacteria of the polymer was analyzed using various instrument techniques. X‐ray diffraction (XRD) results together with Fourier Transform Infrared (FT‐IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) studies confirmed the morphology of Nd‐doped CH‐graft‐poly(N‑tert‑BAAm) composites without any other impurities. The antibacterial effect of Nd was studied by adding it to the copolymer in a weight ratio of 0.5%–2%. The antibacterial effect of neodymium concentration on four different strains of bacteria was investigated: Escherichia coli (ATCC 25922) (E. coli), Pseudomonas aeruginosa (DSM 50071) (P. aeruginosa), Bacillus subtilis (DSM 1971) (B. subtilis), and Staphylococcus aureus subsp. aureus (ATCC 25923) (S. aureus). The antibacterial activities of the obtained composites were determined using the Agar Well Diffusion Assay Method. Experimental results show that Nd binds well to CH‐graft‐poly(N‑tert‑BAAm). Activity against E. coli, P. aeruginosa, B. subtilis, and S. aureus subsp. aureus creates a potential for pharmaceutical and biomedical applications.

Today, essential oils are considered safe substances and can be used as antibacterial additives. Pimpinella anisum L. (Aniseed) and Foeniculum vulgare Mill. var. dulce (fennel) species are of great economic importance. It is among the medicinal and aromatic plants cultivated in wide areas in our country. In this study, it was aimed to determine the antimicrobial properties of essential oils obtained from Foeniculum vulgare Mill. and Pimpinella anisum L plants. The essential oils of the species were obtained by using the distillation method. The antimicrobial activities of essential oils by hand were studied using the hollow agar method. Known to be medically important in food, cosmetics and pharmaceutical products Enterobacter aerogenes (ATCC 13048), Enterococcus faecalis (ATCC 29212), Salmonella enteritidis (ATCC 13075), Staphylococcus aureus subsp. aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Serratia marcescens (ATCC 13880) evaluated against pathogen and microbial contaminants. While Foeniculum vulgare showed results parallel to the antibiotic used as standard, no antibacterial activity was observed in Pimpinella anisum L.

ÖzetNeocallimastix sp. ve polisentrik Orpinomyces sp. 12 ticari karbon kaynağı ve 11 bitkisel karbon kaynağı üzerinde geliştirilerek β-1,4-endoglukanaz, β-1,4-endoksilanaz, β-glukosidaz, β-ksilosidaz üretimleri belirlenmiştir. Enzimler üçüncü günden itibaren besi ortamında toplanmış, en yüksek selülaz aktivite değerleri Neocallimastix sp. ve Orpinomyces sp. 'de sırasıyla karboksimetil selüloz ve tekstil atığından elde edilmiştir. Kolay fermente edilebilen şekerler selüloz üretimini 0.5 U/ml altında kalmasına neden olmuştur. Ksilanaz en yüksek Neocallimastix sp. 'nin karboksimetil selüloz kültüründe, Orpinomyces sp. 'nin fruktoz, maltoz, sükroz, laktoz ve avisel kültürlerinde tespit edilmiş, ayrıca yonca her iki fungus içinde ksilanaz aktivitesini en üst düzeye çıkarmıştır. Neocallimastix sp. 'de b-glikosidaz ve b-ksilosidaz üretimi Orpinomyces sp. 'ye göre daha fazla olmuştur. İnulin her iki fungus tarafından fermente edilse de fungal gelişimleri dolayısıyla da enzim üretimlerini olumsuz etkileyen tek substrat olmuştur. Ksilanazın sürekli salgılanma doğası anaerobik fungusların konak hayvanın hemiselülozdan faydalanmasında önemli rol oynadığını göstermektedir.Anahtar sözcükler : Neocallimastix, Orpinomyces, Selülaz, Ksilanaz, β-glukosidaz, β-ksilosidaz Effects of Carbon Sources on Enzyme Production ofNeocallimastix sp. ve Orpinomyces sp. SummaryNeocallimastix sp. and Orpinomyces sp. was grown by using 12 commercial carbon sources and 11 plant carbon sources. β-1,4-endoglucanase, β-1,4-endoxylanase, β-glucosidase, β-xylosidase synthesis by these fungi were determined. Enzymes accumulated on culture medium after three days. The maximum cellulase activities of Neocallimastix sp. and Orpinomyces sp. was observed in the cultures of carboxymethyl cellulose and textile waste, respectively. In the cultures of readily fermentable sugars, cellulase activity was under 0.5 U/ml. Xylanase activity was found to be maximum in carboxymethyl cellulose culture of Neocallimastix sp. However maximum xylanase activities of Orpinomyces sp. was found in fructose, maltose, sucrose, lactose and avicel cultures. Xylanase production of both fungi was also induced by alfalfa hay. Neocallimastix sp. produced more β-glicosidase and β-xylosidase than Orpinomyces sp. Inulin was fermented by both fungi, however inulin was the only substrate that caused poor growth and enzyme production. The continuous secretion of xylanase reflected the role of anaerobic fungi in hemicellulose degradation in host animal. Keywords