Elemental composition of seston and nutrient dynamics in the Sea of Marmara

The Sea of Marmara, an intercontinental basin with shallow and narrowstraits, connects the Black and Mediterranean Seas. Data obtained during1991–1996 have permitted the determination of the elementalcomposition of seston in the euphotic zone and the N:P ratio of thesubhalocline waters of the Marmara Sea. Since primary production is alwayslimited to the less saline upper layer (15–20 m), of the Marmara Sea,the subhalocline waters of Mediteranean origin are always rich in nutrients(NO₃ + NO₂ = 8–10 μm, PO₄ = 0.8–1.2 μm) but depleted in dissolvedoxygen (30–50 μm) throughout the basin, yielding an -O_{_2} : N : P ratio of 178 : 9 : 1. Pollution of the surfacewaters since the 60s has modified the subhalocline nutrient chemistryslightly. In the euphotic zone, the N : P ratio of the seston changes from5.9 to 9.5 between the less and more productive periods. Though the biologyof the Marmara has changed significantly during the previous two decades,the close relationship observed between the elemental composition of thesurface seston and the NO₃ : PO₄ ratio of thesubhalocline waters strongly suggests that during the whole year primaryproduction throughout the basin and POM export to the lower layer remainnitrogen-limited. This suggestion needs to be confirmed by bio-assays,biological studies and sediment trap data from the upper subhaloclinedepths. Nonetheless, the counterflows in the Marmara basin possessrelatively low N : P ratios in both dissolved and particulate nutrients andextend as far as the adjacent seas. This revised version was published online in July 2006 with corrections to the Cover Date.     

Circadian variation in the structure of mast cells

Circadian variation in the structure of mast cells has been demonstrated histologically. At 11.00 h the number of mast cells was increased and at 03.00 h it was significantly decreased (p less than 0.01). Morphological analysis has also supported this phenomenon.     

Induction of defense-related enzymes in soybean leaves by class IId bacteriocins (thuricin 17 and bacthuricin F4) purified from Bacillus strains

We have recently discovered a new class of bacteriocin (class IId) which stimulates plant growth in a way similar to Nod factors. Nod factors have been shown to provoke aspects of plant disease resistance. We investigated the effects of bacteriocins [thuricin 17 (T17) and bacthuricin F4 (BF4)] on the activities of phenylalanine ammonia lyase (PAL), guaiacol peroxidase (POD), ascorbate peroxidase (APX), superoxide dismutase (SOD), and polyphenol oxidase (PPO). Bacteriocin solutions were fed into the cut stems of soybean (Glycine max L. Merr. cv. OAC Bayfield) seedlings at the first trifoliate stage. PAL activity in T17 treated leaves was the highest at 72 h after treatment and was 75.5% greater than the control at that time. At 72 h after treatment POD activities in T17 and BF4 treated leaves increased by 72.7 and 91.3%, respectively, as compared with the control treatment. APX activity was 52.3 and 49.6% respectively, greater than the control in T17 and BF4 treated leaves at 72 h after treatment. SOD activity in T17 treated leaves was the highest at 72 h after treatment and was 26.0% greater than the control at that time. SOD activity was 70.5 and 60.2% greater, respectively, than the control in T17 and BF4 treated leaves, at 72 h. Using PAGE we found that one APX isozyme (28 kDa isoform) showed the strongest induction in all bacteriocin treated leaves at 72 h. Activity of the seven SOD isozymes was increased by both bacteriocins, relative to the control treatment. The 33 kDa PPO isozyme was induced strongly by both bacteriocins, relative to the control treatment. These results indicate that class IId bacteriocins can act as an inducer of plant disease defense-related enzymes and may be acting through mechanisms similar to Nod factors.     

Suitability indices and habitat suitability index model of Caspian kutum (Rutilus frisii kutum) in the southern Caspian Sea

The relationship between species and habitat is important in ecosystem-based fisheries management. Habitat suitability index (HSI) modeling is a valuable tool in ecology and can be used to describe the relationship between fish abundance and ecological variables in order to estimate the suitability of specific habitats. In the present study, an HSI model was applied to determine suitable habitats for the Caspian kutum (Rutilus frisii kutum), an important commercial species in the southern Caspian Sea. An arithmetic mean model (AMM) was found to be the most appropriate model for describing the relationship between two of the environmental variables investigated (depth and benthos biomass). However, a geometric mean model explained the evident relationship when all four environmental variables were used (depth, benthos biomass, photosynthetically active radiation and sea surface temperature). The areas with an HSI > 0.5 had over 85 % of the total catch indicating the reliability of the prediction of the Caspian kutum habitat using the AMM. The present study showed that depth and substrate structure are the most important environmental variables for the Caspian kutum to select its habitats, and between remotely sensed data, chlorophyll a, photosynthetically active radiation and sea surface temperature are the most critical parameters for near real-time prediction of the Caspian kutum habitat.     

Synthesis and inhibitory properties of some carbamates on carbonic anhydrase and acetylcholine esterase

A series of carbamate derivatives were synthesized and their carbonic anhydrase I and II isoenzymes and acetylcholinesterase enzyme (AChE) inhibitory effects were investigated. All carbamates were synthesized from the corresponding carboxylic acids via the Curtius reactions of the acids with diphenyl phosphoryl azide followed by addition of benzyl alcohol. The carbamates were determined to be very good inhibitors against for AChE and hCA I, and II isoenzymes. AChE inhibition was determined in the range 0.209–0.291?nM. On the other hand, tacrine, which is used in the treatment of Alzheimer’s disease possessed lower inhibition effect (K_i: 0.398?nM). Also, hCA I and II isoenzymes were effectively inhibited by the carbamates, with inhibition constants (K_i) in the range of 4.49–5.61?nM for hCA I, and 4.94–7.66?nM for hCA II, respectively. Acetazolamide, which was clinically used carbonic anhydrase (CA) inhibitor demonstrated K_i values of 281.33?nM for hCA I and 9.07?nM for hCA II. The results clearly showed that AChE and both CA isoenzymes were effectively inhibited by carbamates at the low nanomolar levels.     

Wound healing effects of methanol extract of Laurocerasus officinalis roem

Laurocerasus officinalis Roem. (syn: Prunus laurocerasus L.) is a member of Rosaceae family. We investigated the antimicrobial and antioxidant activity of L. officinalis Roem in wound healing both in vivo and in vitro using an excisional wound model model in mice. We used four groups of eight mice as follows: untreated (control), empty gel, extract + gel (L. officinalis + gel), and Madecassol® groups. All treatments were applied topically once daily. The scar area, percentage wound closure and epithelization time were measured. L. officinalis promoted wound healing and increased granulation tissue, epidermal regeneration and angiogenesis. L. officinalis extract, which is known for its antioxidant and antimicrobial activities, may be useful for promoting wound healing.     

8-Br-cADPR, a TRPM2 ion channel antagonist,inhibits renal ischemia–reperfusion injury

The transient receptor potential melastatin-2 (TRPM2) channel belongs to the transient receptor potential channel superfamily and is a cation channel permeable to Na⁺ and Ca ²⁺. The TRPM2 ion channel is expressed in the kidney and can be activated by various molecules such as hydrogen peroxide, calcium, and cyclic adenosine diphosphate (ADP)-ribose (cADPR) that are produced during acute kidney injury. In this study, we investigated the role of 8-bromo-cyclic ADP-ribose (8-Br-cADPR; a cADPR antagonist) in renal ischemia–reperfusion injury using biochemical and histopathological parameters. CD38, cADPR, tumor necrosis factor-α, interleukin-1β, and myeloperoxidase (inflammatory markers), urea and creatinine, hydrogen peroxide (oxidant), and catalase (antioxidant enzyme) levels that increase with ischemia–reperfusion injury decreased in the groups treated with 8-Br-cADPR. In addition, renin levels were elevated in the groups treated with 8-Br-cADPR. Histopathological examination revealed that 8-Br-cADPR reduced renal damage and the expression of caspase-3 and TRPM2. Our results suggest that the inhibition of TRPM2 ion channel may be a new treatment modality for ischemic acute kidney injury.     

Determination of serum retinol by reversed-phase high-performance liquid chromatography

A rapid, sensitive and specific high-performance liquid chromatographic method was developed for the determination of serum levels of retinol in humans. A direct serum injection technique after deproteinisation was used to avoid lengthy pretreatment steps which can result in degradation of retinol during analysis. The column used was CLC-ODS, the mobile phase was acetonitrile-water and detection wavelength was 328 nm. Deterioration in column performance was not observed even after injection of 300 samples. The lower detection limit was 10 μg/l. On analyzing a serum pool six times, a C.V of 0.7% was obtained. The method is quantitative, reproducible, rapid and highly accurate for routine analysis.     

Extraction of the essential oil from endemic Origanum bilgeri P.H.Davis with two different methods: comparison of the oil composition and antibacterial activity

The antibacterial activity and chemical composition of the essential oils (EOs) isolated from Origanum bilgeri P.H.Davis by two different extraction methods, i.e., hydrodistillation (HD) and solvent-free microwave extraction (SFME), were examined. This endemic Origanum species had shown very good antibacterial activity. The composition of the O. bilgeri EOs obtained by SFME and HD was investigated by GC/MS analysis. The main components of the oils obtained by both methods were carvacrol (90.20-84.30%), p-cymene (3.40-5.85%), γ-terpinene (0.47-1.20%), and thymol (0.69-1.08%). The EO isolation by SFME offered many important advantages, including a higher extraction yield, a shorter extraction time, and a higher content of the active component carvacrol. The carvacrol-rich oils obtained by both HD and SFME showed a good antibacterial activity. The largest inhibition zones were observed for the O. bilgeri EO obtained by SFME. Our study suggests that O. bilgeri EO has the potential to be used as preventative against bacterial contamination in many foods, instead of the common synthetic antimicrobial products.