Sensitive Bacteria Research Articles

Development of new active packaging film made from a soluble soybean polysaccharide incorporated Zataria multiflora Boiss and Mentha pulegium essential oils

An active edible film from soluble soybean polysaccharide (SSPS) incorporated with different concentrations of Zataria multiflora Boiss (ZEO) and Mentha pulegium (MEO) essential oils was developed, and the film’s optical, wettability, thermal, total phenol and antioxidant characteristics were investigated, along with their antimicrobial effectiveness against Staphylococcus aureus, Bacillus cereus, Escherichia coli O157:H7, Pseudomonas aeruginosa and Salmonella typhimurium. The film’s colour became darker and more yellowish and had a lower gloss as the levels of ZEO or MEO were increased. Antioxidant activity of the films was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power assays. DPPH was reduced in the range of 19.84–74.12% depending on the essential oil type and concentration. Film incorporated with 3% (v/v) ZEO showed the highest DPPH radical scavenging activity and ferric reducing antioxidant power (IC50=4188.60±21.73mg/l and EC50=8.86±0.09mg/ml, respectively), compared with the control and MEO added film. Films containing ZEO were more effective against the tested bacteria than those containing MEO. S. aureus was found to be the most sensitive bacterium to both ZEO or MEO, followed by B. cereus and E. coli. A highest inhibition zone of 387.05mm2 was observed for S. aureus around the films incorporated with 3% (v/v) ZEO. The total inhibitory zone of 3% (v/v) MEO formulated films was 21.98 for S. typhimurium and 10.15mm2 for P. aeruginosa. Differential scanning calorimetry (DSC) analysis revealed a single glass transition temperature (Tg) between 16 and 31°C. The contact angle increased up to 175% and 38% as 3% (v/v) of ZEO or MEO used: it clearly shows that films with ZEO were more hydrophobic than those with MEO. The results showed that these two essential oils could be incorporated into SSPS films for food packaging.

Epidemiological control of drug resistance and compensatory mutation under resistance testing and second-line therapy

The fitness cost of antibiotic resistance in the absence of treatment raises the possibility that prudent use of drugs may slow or reverse the rise of resistance. Unfortunately, compensatory mutations that lower this cost may lead to entrenched resistance. Here, we develop a mathematical model of resistance evolution and compensatory mutation to determine whether reversion to sensitivity can occur, and how disease control might be facilitated by a second-line therapy. When only a single antibiotic is available, sensitive bacteria reach fixation only under treatment rates so low that hardly any cases are treated. We model a scenario in which drug sensitivity can be accurately tested so that a second-line therapy is administered to resistant cases. Before the rise of resistance to the second drug, disease eradication is possible if resistance testing and second-line treatment are conducted at a high enough rate. However, if double drug resistance arises, the possibility of disease eradication is greatly reduced and compensated resistance prevails in most of the parameter space. The boundary separating eradication from fixation of compensated resistance is strongly influenced by the underlying basic reproductive number of the pathogen and drug efficacy in sensitive cases, but depends less on the resistance cost and compensation. When double resistance is possible, the boundary is affected by the relative strengths of resistance against the two drugs in the double-resistant-compensated strain.

Glycopeptide antibiotic analogs efficient against vancomycin-resistant bacteria: a patent evaluation (WO2013022763)

The patent claims the preparation of vancomycin analogs equally active against bacterial strains that are primarily sensitive or resistant to this antibiotic. The pseudopeptide core of new compounds carries the amidine group that replaces the carboxamide linking group in the D ring-bearing amino acid residue of the glycopeptide. An elegant method of synthesis of amidine containing glycopeptides via thioamides was developed. The key glycopeptide thioamide analogs were prepared by total multistep synthesis. These analogs can be readily converted to the antibiotic's amidine as well as to alkylamidines, amidrazones, hydroxyamidines and similar analogs. The new analogs are capable of circumventing bacterial resistance derived from the D-Ala-D-Ala to D-Ala-D-Lac alteration – the mechanism operational in the resistant strains VanA and VanB. The interaction of the carboxamide, thioamide and amidine fragments of vancomycin analogs with the targets in resistant and sensitive bacteria was investigated. The novel compounds demonstrated potent activity against VanA-resistant bacteria Enterococcus faecalis (minimal inhibitory concentration = 0.3 − 0.6 μg/ml). However data on susceptible strains and resistant clinical isolates are lacking to further document the interest of the compounds. The results provide evidence for structural modifications that can improve the therapeutic efficacy of vancomycin, in particular, for treatment of vancomycin-resistant infections.

On the interactions of sensitive and resistant Mycobacterium tuberculosis to antibiotics

In this work we propose a system of non linear ordinary differential equations for the dynamics of Mycobacterium tuberculosis (Mtb) within the host, in order to study the role of macrophages, T cells and antibiotics in the control of sensitive and resistant Mtb. Conditions for the persistence of sensitive and resistant bacteria are given in terms of the secondary infections produced by bacteria and macrophages, the immune response, and the antibiotic treatment. Model analysis predicts backward bifurcations for certain values of the parameters. In this case, the dynamics is characterized by the coexistence of two infection states with low and high bacteria load, respectively.

Assessment of phytochemicals, antimicrobial and cytotoxic activities of extract and fractions from Fagonia olivieri (Zygophyllaceae).

BackgroundIn Pakistan Fagonia olivieri (Zygophyllaceae) is commonly used in the indigenous system of medicine for treatment of conditions like diabetes, cancer, fever, asthma, toothache, stomach troubles and kidney disorders. This study evaluated the crude methanol extract of F. olivieri (FOM) and its derived fractions for their antimicrobial and cytotoxic activities as well as the classes of phytochemical.MethodsDried powder of whole plant of F. olivieri was extracted with methanol (FOM) and the resultant was fractionated to give n-hexane fraction (FOH), chloroform fraction (FOC), ethyl acetate fraction (FOE), n-butanol fraction (FOB) and residual aqueous fraction (FOA). Methanol extract and its derived fractions were subjected to phytochemical screening using standard procedures. Also the extract and fractions were assayed for antibacterial, antifungal and cytotoxic activities using agar well diffusion technique, agar tube dilution method and brine shrimps lethality test, respectively.ResultsThe results obtained for phytochemical analysis indicate the presence of saponins and alkaloids in all the tested extract and fractions while anthraquinones were not detected. The results showed that all the bacterial strains tested in this study were susceptible to at least one of the fractions tested. However, FOE and FOB were the best antibacterial fractions and showed antibacterial activity against maximum number of bacterial strains. The results showed that Escherichia coli was the most sensitive bacterium while Bordetella bronchiseptica and Enterobacter aerogenes were less susceptible against various fractions. Maximum percent inhibition for growth was recorded for the fungus Aspergillus flavus with FOE whereas growth of Aspergillus fumigatus and Fusarium solani was inhibited by FOM and its all derived fractions. Minimum LC50 (24.07 mg/L) for brine shrimp assay was recorded for FOE followed by LC50 of FOC (26.1 mg/L) and FOB (30.05 mg/L) whereas maximum LC50 was exhibited by FOH (1533 mg/L).ConclusionThese results indicated the use of F. olivieri to treat infections with emphasis to isolate and characterize the active principle responsible for antibacterial, antifungal and cytotoxic activities and its exploitation as therapeutic agent.

Antioxidative enzyme profiling and biosorption ability of Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 under cadmium stress

Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 were used as cadmium (Cd)-resistant and -sensitive bacteria, respectively, to study their biosorption ability and their antioxidative enzymes. The minimal inhibitory concentration of C. metallidurans CH34 for Cd was found to be 30 mM, and for P. putida mt2 it was 1.25 mM. The tube dilution method revealed the heavy-metal resistance pattern of C. metallidurans CH34 as Ni(2+) (10 mM)>Zn(2+) (4 mM)>Cu(2+) (2 mM)>Hg(2+) (1 mM)>Cr(2+) (1 mM)>Pb(2+) (0 mM), whereas P. putida mt2 was only resistant to Zn(2+) (1 mM). Under Cd stress, the induction of GSH was higher in C. metallidurans CH34 (0.359 ± 0.010 mM g(-1) FW) than in P. putida mt2 (0.286 ± 0.005 mM g(-1) FW). Glutathione reductase was more highly expressed in the mt2 strain, in contrast to non-protein thiols and peroxidase. Unlike dead bacterial cells, live cells of both bacteria showed significant Cd biosorption, i.e. more than 80% at 48 h. C. metallidurans CH34 used only catalase, whereas P. putida mt2 used superoxide dismutase and ascorbate peroxidase to combat Cd stress. This study investigated the Cd biosorption ability and enzymes involved in the Cd detoxification mechanisms of C. metallidurans CH34 and P. putida mt2.

Experimental studies on synergism between meropenem and sulbactam

Meropenem had been successfully used independently against various types of infections when it was first discovered, while sulbactum sodium being much less potent had been given to humans more frequently in combination with ampicillin. Meropenem is now less frequently applied alone in infections caused by virulent multidrug resistant Gram negative organisms. Further, potentiation of action of meropenem is possible by synergism between meropenem and sulbactum. In a study of 30 different Gram positive and Gram negative bacteria, the Minimum Inhibitory Concentration (MIC) of meropenum was found to be varying from 1 to 5 µg/ml with respect to 22 organisms as determined by agar dilution technique; however, the MIC of this antibiotic was 25 µg/ml against Klebsiella pneumoniaeand Pseudomonas aeruginosa. The MIC of sulbactum against meropenem sensitive bacteria was 25 µg/ml and was between 50 and 200 µg/ml against the organisms which had higher MIC values in respect of meropenem. A highly significant synergism could be observed between these two antibiotics by following Student’s ‘t’ test (p<0.001). The fractional inhibitory concentration (FIC) index value of this combination with the help of checkerboard assessment procedure was found to be 0.375, confirming synergism. Key words: Meropenem, sulbactam, Gram positive and Gram negative bacteria,Klebsiella pneumoniae, Pseudomonas aeruginosa.

Essential Oil of Satureja calamintha subsp. nepeta (L.) Briq. from Algeria: Analysis, Antimicrobial and Antioxidant Activities

The essential oil of Algerian Satureja calamintha subsp. nepeta (L.) Briq. obtained by hydrodistillation, was investigated using both capillary GC and GC-MS techniques and assayed for its antimicrobial and antioxidant activities. Twenty six components representing 98.2 % of the oil were characterized. Oxygenated monoterpenes (97.4 %) was the predominant class with pulegone (39.5 %), neo-menthol (33 %) and isomenthone (19.6 %) as major constituents. The antimicrobial activity of the oil was assessed by the disc diffusion method against six bacteria and two fungi. Minimal inhibitory concentrations (MIC) were determined by using the agar dilution against the sensitive microbial species, the results of the antimicrobial assays showed that Staphylococcus aureus was the most sensitive bacteria to this oil (MIC=0.25 %). The antioxidant activities of the essential oils were evaluated by DPPH free radical-scavenging and reducing power. For both tests, S. calamintha oil showed a low activity, which was less efficient than those of BHT and BHA.

Chemical Communication of Antibiotic Resistance by a Highly Resistant Subpopulation of Bacterial Cells

The overall antibiotic resistance of a bacterial population results from the combination of a wide range of susceptibilities displayed by subsets of bacterial cells. Bacterial heteroresistance to antibiotics has been documented for several opportunistic Gram-negative bacteria, but the mechanism of heteroresistance is unclear. We use Burkholderia cenocepacia as a model opportunistic bacterium to investigate the implications of heterogeneity in the response to the antimicrobial peptide polymyxin B (PmB) and also other bactericidal antibiotics. Here, we report that B. cenocepacia is heteroresistant to PmB. Population analysis profiling also identified B. cenocepacia subpopulations arising from a seemingly homogenous culture that are resistant to higher levels of polymyxin B than the rest of the cells in the culture, and can protect the more sensitive cells from killing, as well as sensitive bacteria from other species, such as Pseudomonas aeruginosa and Escherichia coli. Communication of resistance depended on upregulation of putrescine synthesis and YceI, a widely conserved low-molecular weight secreted protein. Deletion of genes for the synthesis of putrescine and YceI abrogate protection, while pharmacologic inhibition of putrescine synthesis reduced resistance to polymyxin B. Polyamines and YceI were also required for heteroresistance of B. cenocepacia to various bactericidal antibiotics. We propose that putrescine and YceI resemble "danger" infochemicals whose increased production by a bacterial subpopulation, becoming more resistant to bactericidal antibiotics, communicates higher level of resistance to more sensitive members of the population of the same or different species.

Determination of the mode of action of enterolysin A, produced by Enterococcus faecalis B9510

The current study aimed to visualize the damage caused by enterolysin A to the cells of sensitive strains and to find out cleavage site within the peptidoglycan moiety of bacterial cell walls. Enterolysin A produced by a local isolate, Enterococcus faecalis B9510 was found to rapidly kill cells of the sensitive strain Lactococcus lactis ssp. cremoris 2144 during 120 min of treatment as compared to the untreated control where no such effect was observed. Transmission electron microscopy of the enterolysin A-treated cells revealed leaking of the cytoplasmic contents ultimately resulting in complete lysis of cell walls. To find the cleavage site, purified cell walls of L. lactis ssp. cremoris 2144, Pediococcus pentosaceus 43201 and Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 were treated with enterolysin A, and liberated amino acids were derivatized for N and C terminals and analysed using thin layer chromatography on silica gel with isopropanol as solvent. The results showed that enterolysin A cleaves the peptide bonds at two locations within peptidoglycan subunits. The first location is between L-alanine and D-glutamic acid of the stem peptide and the other location is between L-lysine of the stem peptide and D-aspartic acid of the interpeptide bridge. Enterolysin A cleaves the peptide bonds within the stem peptide as well as in the interpeptide bridge of Gram-positive bacterial cell walls. This gives a possible reason for the broad spectrum of enterolysin A activity. This is the first report identifying the cleavage site of enterolysin A within the cell walls of sensitive bacteria. This will help in identifying potential applications for enterolysin A.

Probing the Role of the Vancomycin E-Ring Aryl Chloride: Selective Divergent Synthesis and Evaluation of Alternatively Substituted E-Ring Analogues

The selective functionalization of vancomycin aglycon derivatives through conversion of the E-ring aryl chloride to a reactive boronic acid and its use in the synthesis of a systematic series of vancomycin E-ring analogues are described. The series was used to examine the E-ring chloride impact in binding d-Ala-d-Ala and on antimicrobial activity. In contrast to the reduced activity of the unsubstituted E-ring derivatives, hydrophobic and relatively nonpolar substituents approach or match the chloro-substituted vancomycin and were insensitive to the electronic character of the substituent (e.g., Cl vs CN/OMe), whereas highly polar substituents fail to provide the enhancements. Moreover, the active permethylated vancomycin aglycon derivatives exhibit VanB VRE antimicrobial activity at levels that approach (typically within 2-fold) their activity against sensitive bacteria. The robust borylation reaction also enabled the functionalization of a minimally protected vancomycin aglycon (N-Boc-vancomycin aglycon) and provides a direct method for the preparation of previously inaccessible analogues.

Synthesis of novel dopamine derived multidirectional ligands from cyanuric chloride: structural and antimicrobial studies.

Two monopodal (2,4-dichloro-6-(3-hydroxytyramine)-1,3,5-triazine) and tripodal (2,4,6-(3-hydroxytyramine)-1,3,5-triazine) s-triazine derivatives were prepared through the reaction of cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) and 3-hydroxytyramine hydrochloride (dopamine hydrochloride). The structures of the compounds were identified by FT-IR, 1H NMR, 13C NMR, thermal analysis and elemental analysis. Their antimicrobial activities were carried out using the broth microdilution method in dimethyl sulfoxide (DMSO): Phosphate Buffered Saline (PBS) against eight bacteria and one yeast. The results of the test were compared with ampicillin. It was determined that CCDOP1, CCDOP3 and DOP have significant antibacterial and antifungal activity. These three chemicals revealed strong antibacterial activity against the E. coli and S. aureus strains used in the study. S. aureus was the most sensitive strain against dopamine hydrochloride and E. coli was the most sensitive bacteria against CCDOP1.

Characterization and identification of a chlorine-resistant bacterium, Sphingomonas TS001, from a model drinking water distribution system

This study describes the identification and characterization of a new chlorine resistant bacterium, Sphingomonas TS001, isolated from a model drinking water distribution system. The isolate was identified by 16s rRNA gene analysis and morphological and physiological characteristics. Phylogenetic analysis indicates that TS001 belongs to the genus Sphingomonas. The model distribution system HPC results showed that, when the chlorine residual was greater than 0.7mgL−1, 100% of detected heterotrophic bacteria (HPC) was TS001. The bench-scale inactivation efficiency testing showed that this strain was very resistant to chlorine, and 4mgL−1 of chlorine with 240min retention time provided only approximately 5% viability reduction of TS001. In contrast, a 3-log inactivation (99.9%) was obtained for UV fluencies of 40mJcm−2. A high chlorine-resistant and UV sensitive bacterium, Sphingomonas TS001, was documented for the first time.

Essential oil composition and antibacterial activity of Achillea millefolium L. from different regions in North east of Iran

Achillea millefolium L. belongs to Asteraceae family and widely distributed in Mountainous and Steppe regions of Golestan province. The aerial parts of plant were collected from two different regions (700 to 2300 m) and the essential oils were obtained by hydro distillation. Essential oil compositions were analyzed by Gas chromatography-mass spectrometry (GC-MS). Different compounds were identified and their yield was 99.43 and 99.70%, respectively in Maraveh Tapeh and Charbagh regions. 1,8-cineole (18.6%), camphor (13.9%), borneol (9.4%), terpinolene (8.6%), γ-terpinene (6.8%) and thujone (4.3%) were the major components oil in 2300 m, whereas terpinolene (81%) followed by borneol (4.2%), β-pinene (3.5%) and chamazulene (2.9%) were identified in the flower oil in 700 m. The antibacterial activities were studied in vitro against 9 Gram positive and negative bacteria. The bacterial strains tested were found to be more sensitive to essential oil in which obtained in 2300 m and showed a very effective bactericidal activity with minimum inhibitory concentrations (MIC) ranging from 12.6 to 112 μg/ml. S. epidermicis, S. aureus, B.cereus, E. faecalis and E. coli were the most sensitive bacteria from oil of 2300 m, whereasS. aureus was the most sensitive bacteria, B. cereus, E. coli and S. typhimorium have moderate sensitivity and other bacteria were resistant to the oil of 700 m. E. coli and E.faecalis with 16.5 and 14.2 mm inhibition zone were sensitive Gram negative bacteria with MIC 22.8 and 63.8 μg/ml, respectively. Results demonstrate that the oil of A. millefolium L. can become potentials for controlling certain important Gram positive and negative bacteria which produces many infectious diseases, but their effective is varied in different region. Key words: Achillea millefolium L., essential oil, 1,8-cineole, terpinolene, Bacillus cereus,Staphylococcus aureus, Escherichia coli.

Physicochemical surface properties of Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 under cadmium stress

Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 were used as cadmium (Cd) resistant and sensitive bacteria, respectively to study the effect of Cd on physicochemical surface properties which include the study of surface charge and hydrophobicity which are subjected to vary under stress conditions. In this research work, effective concentration 50 (EC50 ) was calculated to exclude the doubt that dead cells were also responding and used as reference point to study the changes in cell surface properties in the presence of Cd. EC50 of C. metallidurans CH34 was found to be 2.5 and 0.25 mM for P. putida mt2. The zeta potential analysis showed that CH34 cells were slightly less unstable than mt2 cells as CH34 cells exhibited -8.5 mV more negative potential than mt2 cells in the presence of Cd in growth medium. Cd made P. putida mt2 surface to behave as intermediate hydrophilic (θw = 25.32°) while C. metallidurans CH34 as hydrophobic (θw = 57.26°) at their respective EC50 . Although belonging to the same gram-negative group, both bacteria behaved differently in terms of changes in membrane fluidity. Expression of trans fatty acids was observed in mt2 strain (0.45%) but not in CH34 strain (0%). Similarly, cyclopropane fatty acids were observed more in mt2 strain (0.06-0.14%) but less in CH34 strain (0.01-0.02%). Degree of saturation of fatty acids decreased in P. putida mt2 (36.8-33.75%) while increased in C. metallidurans CH34 (35.6-39.3%). Homeoviscous adaptation is a survival strategy in harsh environments which includes expression of trans fatty acids and cyclo fatty acids in addition to altered degree of saturation. Different bacteria show different approaches to homeoviscous adaptation.

Chemical composition and antimicrobial activity of berry essential oil of Juniperus oxycedrus L. (Cupressaceae) grown wild in Republic of Macedonia

Chemical composition and antimicrobial activity of essential oil isolated from berries from 2 different samples of Juniperus oxycedrus L. (Cupressaceae), growing wild in Republic of Macedonia was investigated. Performing GC/FID/MS analysis, one hundred components were identified, representing 96.0-98.95% of the oil. The major components were α-pinene (22.54- 27.12%), myrcene (11.26- 15.13%) and limonene (2.78-18.06%). Antimicrobial screening of the J. oxycedrus essential oils was made by disc diffusion and broth dilution method against 16 bacterial isolates of Gram positive and Gram negative bacteria and one strain of Candida albicans. The most sensitive bacteria was Haemophilus influenzae (MIC = 125 ml/ml). The essential oils showed moderate antimicrobial activity against Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyogenes, Corynebacterium spp., Escherichia coli and Campilobacter jejuni (MIC &gt; 500 ml/ml) and no activity against Candida albicans, Staphylococcus epidermidis, Acinetobacter spp., Salmonella enteritidis, Shigella flexnery, Klebsiella pneumonia, Pseudomonas aeruginosa, Enterococcus and Proteus mirabilis.

The Population and Evolutionary Dynamics of Phage and Bacteria with CRISPR–Mediated Immunity

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), together with associated genes (cas), form the CRISPR–cas adaptive immune system, which can provide resistance to viruses and plasmids in bacteria and archaea. Here, we use mathematical models, population dynamic experiments, and DNA sequence analyses to investigate the host–phage interactions in a model CRISPR–cas system, Streptococcus thermophilus DGCC7710 and its virulent phage 2972. At the molecular level, the bacteriophage-immune mutant bacteria (BIMs) and CRISPR–escape mutant phage (CEMs) obtained in this study are consistent with those anticipated from an iterative model of this adaptive immune system: resistance by the addition of novel spacers and phage evasion of resistance by mutation in matching sequences or flanking motifs. While CRISPR BIMs were readily isolated and CEMs generated at high rates (frequencies in excess of 10−6), our population studies indicate that there is more to the dynamics of phage–host interactions and the establishment of a BIM–CEM arms race than predicted from existing assumptions about phage infection and CRISPR–cas immunity. Among the unanticipated observations are: (i) the invasion of phage into populations of BIMs resistant by the acquisition of one (but not two) spacers, (ii) the survival of sensitive bacteria despite the presence of high densities of phage, and (iii) the maintenance of phage-limited communities due to the failure of even two-spacer BIMs to become established in populations with wild-type bacteria and phage. We attribute (i) to incomplete resistance of single-spacer BIMs. Based on the results of additional modeling and experiments, we postulate that (ii) and (iii) can be attributed to the phage infection-associated production of enzymes or other compounds that induce phenotypic phage resistance in sensitive bacteria and kill resistant BIMs. We present evidence in support of these hypotheses and discuss the implications of these results for the ecology and (co)evolution of bacteria and phage.

The Investigation of Antibacterial Activities of Ethanol and Methanol Extracts of Flavoparmelia caperata (L.) Hale (Parmeliaceae) and Roccella phycopsis Ach. (Roccellaceae) Lichens Collected from Eastern Blacksea Region, Turkey

This study evaluates antibacterial activities of extracts of Flavoparmelia caperata and Roccella phycopsis by disc-diffusion and broth dilution methods against seven gram positive and nine gram negative bacteria. The solvents used as extractants in this study were ethanol and methanol. The antibacterial activities of lichen extracts were comparable with penicillin, tetracycline and gentamicin, commonly used antibiotics for the treatment of infections. Antibacterial activities of lichen extracts ranged from 14-26 mm. It was observed from the studies that the most resistant bacteria was Bacillus megaterium and the most sensitive bacteria was Proteus vulgaris. Studied lichen extracts have antibacterial activity on both gram negative and gram positive bacteria. The minimum inhibitory concentration values of the lichen extracts were ranged from 58-7500 µg/mL. Our studies suggest that methanol and ethanol extracts of Flavoparmelia caperata and Roccella phycopsis could be an alternative of the antibiotic to cure the diseases.

Total Phenolic, Total Flavonoids, Antioxidant and Antimicrobial Activities of Scrophularia Striata Boiss Extracts

Scrophularia striata (Scrophulariaceae family) is an herbaceous plant that is traditionally used for treatment of microbial infections. Antimicrobial and antioxidant activity of different extracts (methanolic, ethanolic, aqueous and ethyl acetate) from S. striata aerial parts was evaluated. The antimicrobial activity of different extracts from S. striata was evaluated against a large number of bacteria and fungi by micro broth dilution. Total phenolic and flavonoid contents were measured and their antioxidant activities evaluated by DPPH assay and beta carotene linoleic acid test. Antimicrobial screening exhibited the positive relation between the total phenolic content and its antimicrobial activity but their antioxidant activity had a negative relation. Further studies are recommended against clinical isolate of sensitive bacteria and deep investigation on flavonoid and phenolic compounds of S. striata and detecting the antioxidant portion in aqueous extract.

&lt;b&gt;Anammox Bakterilerinin Zenginleştirilmesinde Farklı Dolgu Malzemelerinin Etkisi&lt;/b&gt; / The Effect of Different Filling Materials in Anammox Bacteria Enrichment

Anaerobik amonyum oksidasyonu (Anammox) anoksik ortamda amonyumun elektron verici nitritin elektron alıcı olarak azot gazına oksitlendiği proses olarak bilinmektedir. Konvansiyonel nitrifikasyon-denitrifikasyon prosesleriyle karşılaştırıldığında Anammox prosesinde daha az oksijen kullanılmakta ve hiçbir organik madde (metanol, glikoz) içeriğine gerek duyulmamaktadır. Ancak sayılan avantajlarının yanı sıra Anammox bakterilerinin yavaş büyüme oranı (11-30 gün) dezavantajını oluşturmaktadır. Dolayısıyla bu bakterilerin zenginleştirilme safhasında özellikle kesikli reaktörler ile çalışmalar yapılmaktadır. Bu çalışmada sürekli olarak işletilen yukarı akışlı reaktörde (UASB-Upflow anaerobic sludge blanket), farklı dolgu malzemeleri kullanılarak hassas ve yavaş büyüyen Anammox bakterilerinin sistemden dışarıya atılmasının engellenmesi amaçlanmaktadır. Sistem yukarı akışlı kolon reaktörde 2 gün hidrolik bekleme süresinde (HRT-Hydraulic retention time) işletilmiştir. Çalışmada seramik taşlar ve Linpor dolgu malzemesi kullanılmıştır. Her iki dolgu malzemesi ile 45 gün işletilen reaktörlerden seramik taşların kullanıldığı reaktörde amonyum azotunun giderimin hızlı bir şekilde %90’lara ulaştığı gözlenmiştir. Linpor dolgu maddelerinin kullanıldığı reaktörde ise amonyum azotunun giderimi daha yavaş olmuştur. Nitrit azotu ise her iki reaktörde de %90’lara varan giderime ulaşmıştır. Stokiyometrik denkleme göre kıyaslandığında Linporlarda çok fazla miktarda nitrat azotunun oluştuğu görülmüştür. 25 gün sonunda Linporlu reaktörde elde edilen sonuçlarla seramik taş dolgulu reaktördeki sonuçlarla benzerlik göstermiştir. The Effect of Different Filling Materials in Anammox Bacteria Enrichment Anaerobic ammonium oxidation (Anammox) is a process that ammonium as electron donor is oxidized to nitrogen gas using nitrite as electron acceptor. Compared to conventional nitrification-denitrification processes, this process is used less oxygen and no organic material (methanol, glucose). However, the slow growth rate of Anammox bacteria (11-30 days) is disadvantages. Therefore, batch reactors have been carried out in these bacteria enrichment. In this study continuously operated upflow anaerobic sludge reactor (UASB) using different filling materials disposing of sensitive and slow-growing Anammox bacteria out of the system is purposed. System is operated up-flow column reactor at 2 days hydraulic retention time (HRT). In this study, ceramic stones and Linpor filling material are used. Both filling material reactors are operated in 45 days. Ceramic stones filling reactor is observed quickly reaches 90% were used reactor ammonium removal. The ammonium nitrogen removal was slower in Linpor filling materials reactor. Nitrite removal is reached up to 90% in both the reactor. When compared to the stoichiometric equation in Linpor was composed of large amounts of nitrate. At the end of 25 days the results were similar to ceramic stone filling reactor with Linpor filling material reactors.