Biochemical composition of Mnemiopsis leidyi in the southern Caspian Sea

The biochemical composition of the invasive ctenophore, Mnemiopsis leidyi from the southern Caspian Sea was analysed in terms of total fractions of protein, lipid, ninhydrin-positive substances (NPS), polysaccharides (PS) and low molecular- weight carbohydrates (LMC). The sum of organic substances per gram dry weight was 84.2 mg g⁻¹. Protein was the major organic fraction followed by lipid and NPS. The NPS/ protein and LNC/PS ratio were 0.45 and 0.50 respectively. Starvation of M. leidyi for a 5-day period resulted in a 32.7% reduction of total organic content. These data will be important in evaluating the feeding condition of M. leidyi specimens from the field. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physiological effects of psyllid (Paratrioza cockerelli) on potato

Feeding by psyllid nymphs causes “Psyllid yellows,” a characteristic yellowing of shoots which results in a dramatic loss of tuber yield. If psyllid infestation is not controlled, the onset of shoot yellowing and growth reductions can occur within two weeks. When insecticides are applied after yellowing, recovery of plants often is not complete. In this study comparisons were made of the physiology and growth of tops and tubers of recovered and permanently injured potatoes of the cultivars ‘Denali,’ ‘Kennebec,’ and ‘Norgold Russet.’ Permanently injured plants senesced rapidly, developed less shoot growth, aerial tubers and shortened and thickened internodes. They had lower tuber yields than plants that recovered. Permanently injured ‘Denali’ developed shoots on old flowering stems. In permanently injured plants of all cultivars, the tubers were small and badly misshapen but numbers increased. In recovered ‘Kennebec’ plants tubers were also misshapen, but were of average size. Tubers of recovered ‘Denali’ and ‘Norgold Russet’ were of acceptable shape. In samplings made during tuber growth, dry weight percentages of total soluble sugars, sucrose and glucose of tubers from permanently injured plants were found to be the same as those of recovered plants. In all cultivars, starch percentages of tubers from permanently injured plants were higher than that of the recovered, but the pattern of carbohydrate content changes was similar for permanently injured and recovered cultivars.     

Replacement of fishmeal with rice protein concentrate in practical diets for European sea bass Dicentrarchus labrax reared at winter temperatures

As no information is available regarding the efficacy of using rice protein concentrate (RPC) to replace fishmeal (FM) in diets for European sea bass (Dicentrarchus labrax), a trial was conducted to determine the optimum inclusion for European sea bass juveniles. Diets were formulated to replace 25%, 50% and 75% of fishmeal with RPC. Additional high level inclusion diets (50% and 75%) were supplemented with lysine and methionine to determine if these were limiting factors. Fish (18.0 ± 0.06 g) were fed the experimental diets for 12 weeks. The final mean weight and specific growth rate (SGR) were significantly higher in fish fed the control diet (diet FM) and low level RPC (diet RPC25) than in fish fed the other diets. The supplementation of the amino acids had a positive effect on growth, elevating the final weight of the high level RPC (RPC75 + AA) group above that of the non‐supplemented group (RPC75). However, this was still not comparable to fish fed FM and RPC25 diets. No significant differences in body composition were observed. A digestibility study demonstrated an inverse relationship between elevating inclusion levels of RPC and apparent digestibility coefficients (ADCs) for dry matter and lipid, with significantly lower values than the control being observed with RPC inclusions above 25%. The mesenteric fat index followed this trend. Circulating leucocyte levels, leucocyte ratios and serum lysozyme activity remained unaffected by dietary treatment. However, compared with the control group, fish fed RPC75, RPC50 + AA RPC75 + AA displayed significantly lower haematocrit values. The present study demonstrates that the inclusion of RPC at 140 g kg^?1 (effectively replacing 25% of FM content) does not compromise European sea bass growth performance, body quality or basic haematological parameters. It is suggested that future studies including higher levels test the efficacy of additional amino acid supplementation (e.g. tryptophan).     

Mapping forest fires by nonparametric clustering analysis

Fires have a noteworthy role to play with regards to ecological and environmental losses in Mediterranean forests. In addition to ecological impacts, fire may create economic, social as well as cultural changes. The detection of fire-scars has critical importance to help decrease losses. In the present study, forest fires recorded in Antalya, one of the most important ecological and tourist regions within the Western Mediterranean, were clustered and mapped. Since the dominant factors and devastation records derived from the cases had nominal-scaled properties, a categorical data-based nonparametric clustering algorithm was performed in this evaluation. The proposed tool, k-modes algorithm, uses modes instead of means for clustering. The algorithm may be implemented quickly and does not make distributional assumptions concerning the available data. It uses a frequency-based method to update the modes of the fires. The derived modes from the maps may be useful information for local authorities to manage. In conclusion, the proposed nonparametric clustering procedure may be employed to build a decision-support system to monitor and identify fire activities and to enhance fire management efficiency.     

Diversity of five glutenin loci within durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husn.) germplasm grown in Algeria

The HMW and B‐LMW glutenin subunits composition of 120 durum wheat germplasm grown in Algeria was examined using SDS‐PAGE. All together, 39 glutenin patterns were detected, including eight for HMW and 21 for B‐LMW glutenin subunits. Twenty‐six different alleles were identified for the five glutenin loci studied, that is, Glu‐A1 (3), Glu‐B1 (7), Glu‐A3 (5), Glu‐B3 (9) and Glu‐B2 (2). Two new alleles were found at Glu‐B3 locus: Glu‐B3new₁ encodes for five subunits (7 + 8 + 14 + 16 + 18) and Glu‐B3new₂ codes for five subunits (4 + 6* + 12 + 15 + 15*), of which subunit 15* with mobility between bands 15–16 was not described previously. At the Glu‐1 loci, the Glu‐A1c/Glu‐B1e allelic composition was predominant. For the B‐LMW glutenins, the most common allelic composition was Glu‐A3a/Glu‐B3a/Glu‐B2a. The collection analysed shows glutenin alleles and allele combinations related to high gluten strength. This information could be useful to select varieties with improved quality and also as a source of genes to develop new lines when breeding for quality.     

Bioaccumulation, Detection and Analyses of Heavy Metal Pollution in Sultan Marsh and Its Environment

Sultan Marsh is one of the largest and most important wetlands in Turkey, Middle East and Europe, embodying saline and fresh water ecosystems, which provide a shelter for 426 bird species. The area has begun to contribute much to the tourism of Kayseri state and its environs. However, the sites in the vicinity of the sewerage – sludge and fertilizer plants are highly damaged due to pollution. As such, studies on the heavy metal status of water, sediment and plants were investigated. Phragmites australis, Ranunculus sphaerosphermus plants and samples of sediments were taken from 13 different stations of this Marsh. All sampling sites in the study area basin were generally more or less polluted when compared with the control sites. Cr concentrations in the roots of the plants were higher than in the sediment. The tissues of Phragmites australis accumulated heavy metals more than those of Ranunculus sphaerosphermus. The heavy metal accumulation in different parts of plants followed the sequence: root > stem > leaf. Both plants can be used as biological indicators while determining environmental pressures; however, Phragmites australis proved more appropriate for such studies.     

Degradation of certain aromatic compounds by rhizobia

The ability of 22 strains of Rhizobium to degrade catechol, protocatechuic acid, p-hydroxybenzoic acid and salicylic acid all at 1 mm concentration was examined. In the presence of 4.8 mm Na-glutamate, all rhizobia tested degraded catechol (99–100%), p-hvdroxybenzoic acid (79–99%), protocatechuic acid (81 97%) and salicylic acid (20–83%).The concentration of Na glutamate in the medium affected the degradation of the phenolic compounds at 1 mm concentration. Increased glutamate favoured degradation of p-hydroxybenzoic and salicylic acids but had little effect on catechol. Degradation of protocatechuic acid was inhibited by increased glutamate concentration.Rhizobium phaseoli 405 grown with 8.0 mM Na-glutamate, directly cleaved catechol and protocatechuic acid. p-Hydroxybenzoic acid was converted to protocatechuic acid before ring cleavage. Salicylic acid was converted to gentisic acid before further oxidation. O₂ uptake experiments showed that R. phaseoli 405 grown with p-hydroxybenzoic acid was adapted to this compound and protocatechuic acid. A lag of 30 min was required for catechol and salicylic acid.     

Consistency of polyphenol oxidase (PPO) thermostability in ripening apricots (Prunus armeniaca L.): evidence for the presence of thermostable PPO forming and destabilizing mechanisms in apricots

Destabilization of thermostable polyphenol oxidase (TS-PPO) during the ripening of peaches has been previously shown (Yemenicio?lu, A.; Cemero?lu, B. Tr. J. Agric. For. 1998, 22, 261-265). This work studied the effect of ripening on thermal stability of apricot PPO for three different cultivars. Kabaa?i cultivar contained thermolabile PPO, whereas TS-PPO appeared in Hacihalilo?lu and Catalo?lu cultivars. The TS-PPO showed biphasic inactivation curves, and its D and z values between 60 and 90 degrees C varied in the ranges of 357-1.12 min and 11.9-12.7 degrees C, respectively. In Hacihalilo?lu cultivar the TS-PPO was very consistent and existed at all stages of ripening, whereas in Catalo?lu cultivar it appeared only at the half-ripe stage. The loss of consistent TS-PPO in Hacihalilo?lu apricots after partial purification by acetone precipitation and DEAE-cellulose chromatography suggested the non-covalent nature of its stabilization. The main purified fractions (F1 and F2) showed monophasic inactivation curves with similar thermal inactivation parameters (z(F1) = 10.4 degrees C, z(F2) = 10.1 degrees C). However, their kinetic properties against catechol (K(mF1) = 61 mM, K(mF2) = 122.7 mM) and substrate specificities were considerably different. The results of this study showed the presence of TS-PPO forming and destabilizing mechanisms in apricots. Further studies are needed for the solution of these mechanisms and to develop some new strategies that may be utilized by molecular techniques for a planned production of apricot cultivars provided with heat labile but normal PPO activity.     

Antimicrobial activity of some mosses from Turkey

The antimicrobial activity of the methanol extracts of eight mosses species were evaluated at 30 mg/ml concentration against the tested microorganisms.