Should I stay or should I go? Modelling dispersal strategies in saproxylic insects based on pheromone capture and radio telemetry: a case study on the threatened hermit beetle <Emphasis Type="Italic">Osmoderma eremita</Emphasis>

To predict how organisms cope with habitat fragmentation we must understand their dispersal biology, which can be notoriously difficult. We used a novel, multi-pronged approach to study dispersal strategies in the endangered saproxylic hermit beetle Osmoderma eremita, exploiting its pheromone system to intercept high numbers of dispersing individuals, which is not possible with other methods. Mark-release-recapture, using unbaited pitfall traps inside oak hollows and pheromone-baited funnel traps suspended from tree branches, was combined with radio telemetry (in females only) to record displacements. Dispersal, modelled as a probability distribution of net displacement, did not differ significantly between sexes (males versus females recaptured), observation methods (females recaptured versus radio-tracked), or sites of first capture (pitfall trap in tree versus pheromone trap – distance from original dispersal point unknown). A model including all observed individuals yielded a mean displacement of 82 m with 1% dispersing > 1 km. Differences in body length were small between individuals captured in pitfall versus pheromone traps, indicating that dispersal is rarely a condition-dependent response in O. eremita. Individuals captured in pheromone traps were consistently lighter, indicating that most dispersal events occur relatively late in life, which agrees with trap catch data. In addition, most (79%) females captured in pheromone traps were mated, showing that females typically mate before leaving their natal tree. Our data show that integrating odour attractants into insect conservation biology provides a means to target dispersing individuals and could greatly improve our knowledge of dispersal biology in threatened species.     

Flavonoids as tyrosinase inhibitors in in silico and in vitro models: basic framework of SAR using a statistical modelling approach

Flavonoids are widely distributed in plants and constitute the most common polyphenolic phytoconstituents in the human diet. In this study, the in vitro inhibitory activity of 44 different flavonoids (1–44) against mushroom tyrosinase was studied, and an in silico study and type of inhibition for the most active compounds were evaluated too. Tyrosinase inhibitors block melanogenesis and take part in melanin production or distribution leading to pigmentation diseases. The in vitro study showed that quercetin was a competitive inhibitor (IC₅₀=44.38 ± 0.13 µM) and achieved higher antityrosinase activity than the control inhibitor kojic acid. The in silico results highlight the importance of the flavonoid core with a hydroxyl at C7 as a strong contributor of interference with tyrosinase activity. According to the developed statistical model, the activity of molecules depends on hydroxylation at C3 and methylation at C8, C7, and C3 in the benzo-γ-pyrane ring of the flavonoids.     

Evaluation of chalcones as inhibitors of glutathione S‐transferase

Glutathione S‐transferases (GSTs) are the superfamily of multifunctional detoxification isoenzymes and play an important role in cellular signaling. In the present study, potential inhibition effects of chalcones were tested against human GST. For this purpose, GST was purified from human erythrocytes with 5.381 EU?mg^?1 specific activity and 51.95% yield using a GSH–agarose affinity chromatographic method. The effects of chalcones on in vitro GST activity were tested at various concentrations. K_i constants of chalcones were found in the range of 7.76–41.93 μM. According to the results, 4‐fluorochalcone showed a better inhibitory effect compared with the other compounds. The inhibition mechanisms of 2'‐hydroxy‐4‐methoxychalcone and 4‐methoxychalcone were noncompetitive, whereas the inhibition mechanisms of 4'‐ hydroxychalcone, 4‐ fluorochalcone, and 4,4'‐ diflurochalcone were competitive.     

Candida albicans and Saccharomyces cerevisiae cell wall mannans produce fever in rats: role of nitric oxide and cytokines

Mannan components of C. albicans (5 mg/kg, i.p.) and S. cerevisiae (2.5 mg/kg, i.p.) cell walls produced pyrogenic responses which were completely inhibited by indomethacin (5 mg/kg, s.c.) pretreatment in rats. A non-selective NOS inhibitor, L-NAME (10 mg/kg, s.c.), also inhibited the pyrogenic effectiveness of C. albicans mannan, whereas it was ineffective on the fever induced by S. cerevisiae mannan. A selective elevation in the serum TNF-alpha levels was observed at the initial phase of the fever due to S. cerevisiae mannan, whereas there was no significant change on the serum levels of TNF-alpha, IL-1beta and IFN-gamma during the latent period or at the initial phase of the fever induced by C. albicans mannan. Injections of N-linked and/or O-linked oligomannosides of the either mannan did not cause any significant change in the body temperature and serum cytokine levels. These data suggest that the mannan components of C. albicans and S. cerevisiae cell walls produce a prostaglandin-dependent fever in rats. The initial signal for fever seems to be different for each mannan. Data also indicate that integrity of the mannans is necessary for the pyrogenic response.     

Reversible immobilization of uricase on conductive polyaniline brushes grafted on polyacrylonitrile film

Polyacrylonitrile film (PAN) surfaces were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The conductive films were used for immobilization of uricase. The surface resistance of the conductive film in this work was found to be 0.97 kΩ/cm. The maximum amount of immobilized enzyme on conductive film containing 2.4% PANI was about 216 μg/cm². The optimum pH for free and immobilized enzymes was observed at 7.0 and 7.5, respectively. The K _m values for free and immobilized uricase were found to be 94 and 138 μM, respectively. V _max values were calculated as 1.87 and 1.63 U/mg protein for the free and immobilized enzymes, respectively. Immobilized uricase exhibited ~68% of its original activity even after 2 months of storage at 4 °C while the free enzyme lost its initial activity within 4 weeks.     

Is local distribution of the epiphytic lichen <Emphasis Type="Italic">Lobaria pulmonaria</Emphasis> limited by dispersal capacity or habitat quality?

By surveying and re-surveying 12 forest sites in southern Sweden for the epiphytic lichen Lobaria pulmonaria with a 9-year interval, and measuring tree-related habitat quality variables, we have investigated whether the local distribution of the lichen is limited by poor dispersal capacity or by habitat quality. Dispersal distances were measured indirectly as the distances between colonised trees and the nearest trees occupied by L. pulmonaria in both 1992 and 2001. To compare habitat quality between trees occupied by L. pulmonaria and neighbouring control trees, we recorded tree species and measured age and growth rate of trees, light conditions, bark structure and bryophyte cover. The estimated mean dispersal distance was 35 m, with a recorded maximum of 75 m. Occupied trees were larger and had a larger cover of bryophytes than unoccupied trees of similar size. The results indicate that dispersal capacity probably is the most important factor in limiting the local distribution of L. pulmonaria, but habitat-quality factors may be important on a smaller spatial scale.     

Kinetic and docking studies of phenol-based inhibitors of carbonic anhydrase isoforms I, II, IX and XII evidence a new binding mode within the enzyme active site

Carbonic anhydrases (CAs, EC 4.2.1.1) are inhibited by sulfonamides, inorganic anions, phenols, coumarins (acting as prodrugs) and polyamines. A novel class of CA inhibitors (CAIs), interacting with the CA isozymes I, II (cytosolic) and IX, XII (transmembrane, tumor-associated) in a different manner, is reported here. Kinetic measurements allowed us to identify hydroxy-/methoxy-substituted benzoic acids as well as di-/tri-methoxy benzenes as submicromolar-low micromolar inhibitors of the four CA isozymes. Molecular docking studies of a set of such inhibitors within CA I and II allowed us to understand the inhibition mechanism. This new class of inhibitors binds differently compared to all other classes of inhibitors known to date: they were found between the phenol-binding site and the coumarin-binding site, filling thus the middle of the enzyme cavity. They exploit different interactions with amino acid residues and water molecules from the CA active site compared to other classes of inhibitors, offering the possibility to design CAIs with an interesting inhibition profile compared to the clinically used sulfonamides/sulfamates.     

Ki-67 immunostaining and stereologic estimation of nuclear volume in melanocytic skin tumors

OBJECTIVE: To investigate the proliferative activity and mean nuclear volume (MNV) of melanocytic skin tumors. STUDY DESIGN: Proliferative activity, assessed by immunostaining for the Ki-67 monoclonal antibody (reactive with all actively cycling cells), and MNV, estimated by means of a stereologic method, were determined in 60 cutaneous melanocytic tumors, including 28 primary malignant melanomas (PMM), 13 compound nevi (CN), 11 dysplastic nevi and 8 metastatic malignant melanomas. RESULTS: Both MNV and Ki-67 expression differed significantly between CN and other melanocytic tumors and showed a good correlation with Clark's level (a well-established prognostic parameter in PMM). CONCLUSION: The association of proliferative activity and quantitative nuclear features may be helpful in the interpretation of the degree of malignancy in melanocytic skin tumors.     

Effects of bovine milk lactoperoxidase system on some bacteria

Bovine lactoperoxidase (LPO) was purified from skimmed milk using amberlite CG-50-H⁺ resin, CM sephadex C-50 ion-exchange chromatography, and sephadex G-100 gel filtration chromatography. Lactoperoxidase was purified 20.45-fold with a yield of 28.8%. Purity of enzyme checked by sodium dodecyl sulphate-polyacrylamide gel electrophoresis method and a single band was observed. K _m was 0.25 mM at 20°C, V _max value was 7.95 μmol/ml min at 20°C (pH 6.0). Antibacterial study was done by disk diffusion method of Kirby-Bauer using Mueller-Hinton agar medium with slight modification. Bovine LPO showed high antibacterial activity in 100 mM thiocyanate-100 mM H₂O₂ medium for some bacteria (Brevibacillus centrosaurus, B. choshinensis, B. lyticum, Cedecea davisae, Chryseobacterium indoltheticum, Clavibacter michiganense pv. insidiosum, Kocuria erythromyxa, K. kristinae, K. rosea, K. varians, Paenibacillus validus, Pseudomonas syringae pv. populans, Ralstonia pickettii, Rhodococcus wratislaviensis, Serratia fonticola, Streptomyces violaceusniger, Vibrio cholerae-nonO1) respectively, and compared with well known antibacterial substances (levofloxacin, netilmicin). LPO system has inhibition effects on all type bacteria and concentration is really important such as LPO-100 mM thiocyanate-100 mM H₂O₂ system was proposed as an effective agent against many factors causing several diseases.