RESPONSES OF SOME ENZYMES AND KEY GROWTH PARAMETERS OF SALT-STRESSED MAIZE PLANTS TO FOLIAR AND SEED APPLICATIONS OF KINETIN AND INDOLE ACETIC ACID

The study examined the effects of kinetin (KIN) and indoleacetic acid (IAA) applied as seed treatment or sprayed on leaves of salinity stressed plants. Five -week old maize (Zea mays L. cv. ‘DK 647 F1’) plants were grown in pots containing peat and perlite in 1:1 (v/v) mixture. Different treatments used were: 1) control (nutrient solution alone), 2) salt stress [100 mM sodium chloride (NaCl)], 3) 100 mM NaCl and 1 mM kinetin (KIN), 4) 100 mM NaCl and 2 mM KIN, 5) 100 mM NaCl and 1 mM indole acetic acid (IAA), 6) 100 mM NaCl and 2 mM IAA, 7) 100 mM NaCl and 25 mg L^?1 KIN and 8) 100 mM NaCl and 25 mg L^?1 IAA. In treatments 7 and 8 application was to the seeds, for treatments 3-6 it was applied to foliage. The seeds were soaked in KIN or IAA solution for 12 h. Salt stress reduced the total dry matter, chlorophyll content, and relative water content (RWC), but increased proline accumulation, activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC. 1.11.1.7), catalase (CAT; EC. 1.11.1.6) and polyphenol oxidase (PPO; 1.10.3.1) and electrolyte leakage. Both foliar applications of KIN and IAA treatments overcame to variable extents the adverse effects of NaCl stress on the above mentioned physiological parameters. However, seed treatments with KIN or IAA did not improve salinity tolerance in maize plants. Furthermore, foliar application or seed treatments with KIN and IAA reduced the activities of antioxidant enzymes in the salt stressed-plants. Salt stress lowered some macronutrient concentrations [calcium (Ca) and potassium (K) in leaves and roots, phosphorus (P) in roots] but foliar application of both KIN and IAA increased Ca in both leaves and roots and P in leaves. Foliar application of IAA increased K concentrations in leaves of the salt-stressed plants. Foliar application of KIN and IAA, especially at 2 mM concentration, counteracted some of the adverse effects of NaCl salinity by causing the accumulation of proline and essential inorganic nutrients as well as by maintaining membrane permeability.     

Molecular characterisation of quinolone resistance in Escherichia coli from animals in Turkey

The aim of this study were to detect the gyrA, parC and marR mutations and qnr genes (qnrA, qnrB and qnrS) in 120 strains of Escherichia coli isolated from animals. European Committee on Antimicrobial Susceptibility Testing and Clinical Laboratory Standards Institute disc diffusion and minimum inhibitory concentration (MIC) tests, respectively, were used to determine fluoroquinolone (FQ) resistance, and molecular methods were used to detect the mutations and the genes. E coli isolates with an MIC of ≥8 mg/l had mutation at Ser-80 in parC in addition to mutations at Ser-83, Asp-87 or both in gyrA. The nucleotide change was detected in marR (Ser-3?→?Asn, Ala-53?→?Glu, Gly-103?→?Ser, Tyr-137?→?His). Only four E coli isolates (3.3 per cent) contained qnrA and qnrS, and qnrB was not detected. Two E coli isolates from healthy calves also contained qnrA and qnrS. The MICs of enrofloxacin and danofloxacin for qnr-containing E coli isolates ranged from 32 mg/l to 256 mg/l. The results of this study indicated that the FQ-resistant E coli isolates presented an alteration in gyrA (Ser-83?→?Leu, Asp-87?→?Asn) and parC (Ser-80?→?Ile) with high MICs (8-256 mg/l), and there was a low prevalence of qnr genes among E coli isolated from animals.     

A note on the evolution of kabuli chickpeas as shown by induced mutations in <Emphasis Type="Italic">Cicer reticulatum</Emphasis> Ladizinsky

Two distinct chickpeas of the domestic chickpea, C. arietinum L., exist and are referred to as ‘desi’ or microsperma and ‘kabuli’ or macrosperma. Cicer reticulatum Ladiz. is considered to be the wild progenitor of the domestic chickpea. However, the morphological variation in 18 original accessions of C. reticulatum is narrower than those of the domestic chickpeas. The aim of the study is to increase the variability in C. reticulatum. In M₂ generation, a mutant with white flower color was isolated despite of the fact that the parent has the pink flower. Although seed coat color of the parent was dark brown, the mutant was cream like ‘kabuli’ chickpea. It is commonly accepted that the large seeded domestic ‘kabuli’ chickpeas originated from the small seeded ‘desi’ chickpeas, but the induced mutants (white flower and cream seed coat color) of C. reticulatum may suggest an additional path for the evolution of ‘kabuli’ chickpea. ‘Kabuli’ chickpeas could have originated from spontaneous mutants of C. reticulatum. In M₃ generation, multipinnate leaf, erect growth habit, green seed and double-podded chickpeas were isolated. Among these progenies, morphologic variability increased and approached domesticated chickpea. Based on historical records and the induced mutants obtained from this study, the domestic ‘kabuli’ chickpea could have directly emerged from C. reticulatum in ancient Eastern Turkey.     

Evaluation of dietary protein and lipid requirements of two-banded seabream (Diplodus vulgaris) cultured in a recirculating aquaculture system

The objective of this study is to investigate the effects of dietary protein and lipid levels on the growth performance and bioeconomic benefits of two-banded seabream (Diplodus vulgaris) juveniles, a candidate species for aquaculture sector. Eight experimental diets were formulated with four protein (50, 45, 40 and 35 %) levels for each of the two lipid levels (15 and 10 %). Triplicate groups of juvenile fish with an average initial body weight of ~3.64 g were reared in a recirculating aquaculture system and hand fed twice a day until satiation for a period of 60 days. In the experiment, no difference in survival rate was found between the different groups. Relative growth rate (RGR), specific growth rate (SGR), feed conversion ratio (FCR) and daily feed intake were not significantly affected by increasing protein and/or lipid treatments in this present study. However, the RGR, SGR and FCR values showed slightly better efficiency in the experimental group (35/15) fed with lower protein content (35 %) and higher lipid level (15 %) compared with those fed other diets. According to bioeconomic analyses results, the diet with the 35 % protein and 15 % lipid generated the best profit. The results suggest that two-banded seabream can be accepted as a promising alternative species for the aquaculture industry and optimum growth of two-banded seabream fingerlings can be obtained when they are fed a diet containing 35 % crude protein and 15 % crude lipid.     

A general mechanism for network-dosage compensation in gene circuits

Coping with variations in network dosage is crucial for maintaining optimal function in gene networks. We explored how network structure facilitates network-level dosage compensation. By using the yeast galactose network as a model, we combinatorially deleted one of the two copies of its four regulatory genes and found that network activity was robust to the change in network dosage. A mathematical analysis revealed that a two-component genetic circuit with elements of opposite regulatory activity (activator and inhibitor) constitutes a minimal requirement for network-dosage invariance. Specific interaction topologies and a one-to-one interaction stoichiometry between the activating and inhibiting agents were additional essential elements facilitating dosage invariance. This mechanism of network-dosage invariance could represent a general design for gene network structure in cells.     

The occurrence of deep pectoral myopathy in broilers and associated changes in breast meat quality

1. Two experiments were conducted to determine the effect of slaughter weight on the incidence and intensity of deep pectoral myopathy (DPM) of M. pectoralis minor (p. minor muscle) in commercial conditions in Turkey and to evaluate the impact of DPM on meat quality traits of pectoralis major (p. major) muscle in broilers.

2. In Experiment 1, a total of 116 250 carcasses from 59 Ross-308 broiler flocks, classified according to slaughter weight as 2.0–2.2, 2.2–2.4, 2.4–2.6 and >2.6 kg, were evaluated for occurrence of DPM. In Experiment 2, p. major samples from unaffected broilers and each DPM stage were evaluated for meat quality, oxidant and antioxidant properties, nutritional value and fatty acid profile. DPM was characterised as 1: muscles with coagulative necrosis, 2: muscles with fibrous tissue texture and pink to plumb and 3: muscles with green necrotic area.

3. The average incidence of DPM was found to be 0.73% in Experiment 1 and independent of slaughter weight.

4. In Experiment 2, p. major muscle of broilers with DPM 1 and 2 had higher pH values with higher redness and drip loss. All DPM stages resulted in an increase in lipid content and malondialdehyde activity and lowered ash content of p. major muscle compared with unaffected birds. DPM 2 increased superoxide dismutase and glutathione peroxidase activities in M. p. major. The p. major of broilers with DPM had lower content of C18:2 conjugated linoleic and C20:3n-6 fatty acids than those of unaffected broilers. Lower Δ6 desaturase and thiosterase activities and 18:2n-6 to 18:3n-3 ratio were observed for all DPM stages compared to unaffected.

5. It was concluded that these changes obtained in p. major muscle of broilers with DPM might indicate biochemical characteristics of muscle degenerations.     

Nitric oxide improves high zinc tolerance in maize plants

A short-term experiment was carried out to study the effects of exogenous nitric oxide (NO) on some growth parameters and mineral nutrients of maize grown at high zinc (Zn). Maize seedlings were planted in pots containing perlite and subjected to 0.05 or 0.5 mM Zn in nutrient solution. Nitric oxide (0.1 mM) was sprayed to the leaves of maize seedlings. High Zn reduced total dry matter, chlorophyll (Chl.) content and leaf relative water content (RWC), but increased proline content and membrane permeability. Foliar application of NO significantly increased chlorophyll content, RWC and growth of plants treated with high Zn, and significantly reduced their membrane permeability and proline contents. High Zn resulted in increased leaf and root Zn, but lower concentrations of leaf phosphorus (P), and iron (Fe). Foliar application of NO lowered leaf and root Zn and increased leaf and root nitrogen (N) and leaf Fe in the high Zn plants. These results clearly demonstrated that externally-applied NO induced growth improvement in maize plants was found to be associated with reduced membrane permeability under high zinc. Results can be concluded that NO may be involved in nutritional and physiological changes in plants subjected to high Zn.     

Photo-Degradation of Some Dyes using Ag-Loaded Titaniumdioxide

The photocatalytic degradation of organic dyes using TiO₂ andsilver-loaded TiO₂ has beenstudied. The dyes which were chosen (methyl violet, a cationicdye; Cibacron Blue FMR, areactive dye; and Maxilon Red GRL, a mono azo basic dye)represent the major structuralfamilies of organic dyes. Ag-loading dramatically reduceddegradation time. While theundoped TiO₂ degraded about 63% of the total amount ofmethyl violet within 4 min,degradation rose to 95% with Ag-loaded TiO₂ within the sametime period. The photo-decomposition of dyes was monitored as a function of pH anddissolved organic and inorganic matters.