Effects of climatic warming on cold hardiness of some northern woody plants assessed from simulation experiments

Effects of climatic warming on cold hardiness were investigated for some northern woody plants. In the first experiment, seedlings of Norway spruce ( Picea abies [L.] Karst.), Scots pine ( Pinus sylvestris L.) and lodgepole pine ( Pinus contorta Dougl. var. latifolia Engelm.) were exposed to naturally fluctuating temperatures averaging −6°C (ambient) and 0°C (elevated) for 16 weeks in midwinter before they were thawed and re-saturated with water. In lodgepole pine, needle sugar concentrations had decreased by 15%, and the temperature needed to induce 10% injury to needles in terms of electrolyte leakage had increased by 6°C following treatment to elevated as compared with control temperatures. In contrast, Norway spruce and Scots pine showed no effects. The lack of an effect for Scots pine was ascribed to seedlings containing unusually large energy reserves that buffered respiratory expenditure of sugars. A strong, linear relationship between levels of cold hardiness, assessed by the electrolyte leakage method, and sugars was found when combining data from this and previous, similar experiments. In the second experiment, the evergreen dwarf shrub Empetrum hermaphroditum Hagerup was analysed for leaf cold hardiness, using the electrolyte leakage method, and sugar concentrations in late spring and late autumn during the third year of a warming experiment in a subarctic dwarf shrub community. The objective was to test the hypothesis that warming in the growing season alters hardening/dehardening cycles by increasing soil nitrogen mineralization and plant growth. Data found, however, suggested that cold hardening/dehardening cycles were unaffected by warming.     

Effects of 24-epibrassinolide on seed germination, seedling growth, lipid peroxidation, proline content and antioxidative system of rice (Oryza sativa L.) under salinity stress

The effects of 24-epibrassinolide (24-epiBL) on seedling growth, antioxidative system, lipid peroxidation, proline and soluble protein content were investigated in seedlings of the salt-sensitive rice cultivar IR-28. Seedling growth of rice plants was improved by 24-epiBL treatment under salt stress conditions. When seedlings treated with 24-epiBL were subjected to 120 mM NaCl stress, the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) and glutathione reductase (EC 1.6.4.2) did not show significant difference, whereas the activity of ascorbate peroxidase (EC 1.11.1.11) significantly increased. Increased activity of peroxidase (EC 1.11.1.7) under NaCl stress showed remarkable decrease in the 24-epiBL+NaCl-applied group. Lipid peroxidation level significantly increased under salt stress but decreased with 24-epiBL application revealing that less oxidative damage occurred in this group (24-epiBL+NaCl). In addition, increased proline content in the NaCl-applied group was decreased by 24-epiBL application in the 24-epiBL+NaCl-applied group. Soluble protein content was increased by 24-epiBL application even under NaCl stress, being also higher than control conditions (no 24-epiBL or NaCl treatment). 24-epiBL treatment considerably alleviated oxidative damage that occurred under NaCl-stressed conditions and improved seedling growth in part under salt stress in sensitive IR-28 seedlings.     

Purification and Characterization of Glucose-6-Phosphate Dehydrogenase from Rat Small Intestine

Glucose-6-phosphate dehydrogenase (G6PD) was purified from rat small intestine with 19.2% yield and had a specific activity of 53.8 units per miligram protein. The pH optimum was determined to be 8.1. The purified rat small intestinal G6PD gave one activity, one protein band on native PAGE. The observation of one band on SDS/PAGE with an Mr of 48 kDa and a specific activity lower than expected may suggest the proteolytically affected enzyme or different form of G6PD in the rat small intestine. The activation energy, activation enthalpy, Q10, and optimum temperature from Arrhenius plot for the rat small intestinal G6PD were found to be 8.52 kcal/mol, 7.90 kcal/mol, 1.59, and 38 degrees C, respectively. The Km values for G6P and NADP+ were 70.1 +/- 20.8 and 23.2 +/- 7.6 microM, respectively. Double-reciprocal plots of 1/Vm versus 1/G6P (at constant [NADP+]) and of 1/Vm versus 1/NADP+ at constant [G6P]) intersected at the same point on the 1/Vm axis to give Vm = 53.8 U/mg protein.     

Industrial microbiology of solar salt production

Solar salterns can be modeled as giant outdoor chemostats, much like a series of dams on a slow-moving river. Microorganisms and their products play an essential, but sometimes uncharacterized, role in salt production in these ponds, from seawater salinity up through NaCl saturation. They may physically affect the evaporation process and their by-products may chemically modify or bind with dissolved ions. Many solar salt facilities engage microbiologists to establish monitoring programs for analyses of nutrients, standing crop and associated biological variables in the ponds. Other solar salt companies engage microbiologists only when there are “crises” in the ponds that interfere with salt production. Journal of Industrial Microbiology & Biotechnology (2002) 28, 42–47 DOI: 10.1038/sj/jim/7000173 Received 20 May 2001/ Accepted in revised form 13 June 2001     

Effects of milking frequency on lying down and getting up behaviour in dairy cows

The objective of this study was to investigate if cows milked twice per day have more difficulty lying down and getting up and spend less time lying than cows milked three times per day. Seventeen cows of the Swedish Red and White Cattle Breed were studied, seven of which were milked twice daily (2M) and ten were milked three times (3M) daily. They were kept in individual cubicles, that were closed in the rear end with a rope. They had free access to a mixture of silage, hay and concentrate. The individual cows were video-recorded for 24h every fourth week, starting four weeks after calving for four times. The 2M cows stood significantly longer, 128.11min, than the 3M cows, 64.88min, (P<0.01) during the 4h before morning milking. The 2M cows also had a tendency for longer duration of standing rumination (P=0.059) as well as significantly more bouts of standing rumination (P<0.01) during these hours than the 3M cows. The cows in the 3M group spent less time on the getting up movement (P<0.05) during the 4h before morning milking. The distribution of the lying bouts during these 4h differed significantly between the groups, where the 3M cows had fewer lying bouts shorter than 15min and more lying bouts longer than 90min. The results indicate that milking three times a day contributes to increased comfort in high-producing dairy cows.     

Molecular analysis of 16 Turkish families with DHPR deficiency using denaturing gradient gel electrophoresis (DGGE)

Dihydropteridine reductase (DHPR) catalyses the conversion of quinonoid dihydrobiopterin (qBH2) to tetrahydrobiopterin (BH4), which serves as the obligatory cofactor for the aromatic amino acid hydroxylases. DHPR deficiency, caused by mutations in the QDPR gene, results in hyperphenylalaninemia and deficiency of various neurotransmitters in the central nervous system, with severe neurological symptoms as a consequence. We have studied, at the clinical and molecular levels, 17 patients belonging to 16 Turkish families with DHPR deficiency. The patients were detected at neonatal screening for hyperphenylalaninemia or upon the development of neurological symptoms. To identify the disease causing molecular defects, we developed a sensitive screening method that rapidly scans the entire open reading frame and all splice sites of the QDPR gene. This method combines PCR amplification and "GC-clamping" of each of the seven exonic regions of QDPR, resolution of mutations by denaturing gradient gel electrophoresis (DGGE), and identification of mutations by direct sequence analysis. A total of ten different mutations were identified, of which three are known (G23D, Y150C, R221X) and the remaining are novel (G17R, G18D, W35fs, Q66R, W90X, S97fs and G149R). Six of these mutations are missense variants, two are nonsense mutations, and two are frameshift mutations. All patients had homoallelic genotypes, which allowed the establishment of genotype-phenotype associations. Our findings suggest that DGGE is a fast and efficient method for detection of mutations in the QDPR gene, which may be useful for confirmatory DNA-based diagnosis, genetic counselling and prenatal diagnosis in DHPR deficiency.     

Modulation of motor behaviour by NMDA- and cholecystokinin-antagonism

Summary Motor behaviour relies on complex neurochemical interactions in the basal ganglia, in particular the striatum. Antagonistic influences in this region are exerted by afferent projections from, on the one hand, the ventral mesencephalon, utilizing dopamine as a transmitter, and, on the other hand, from the cerebral cortex, signalling by the excitatory amino acid glutamate. The activity in both these neuronal populations appears to be regulated by the neuropeptide cholecystokinin. This article concentrates on interactions between cholecystokinin and glutamate, summarizing some recent morphological, biochemical and behavioural findings. It is suggested that cholecystokinin, acting via the cholecystokininB receptor, potentiates the glutamatergic excitatory input to the striatum.     

Effects of subsidized spiders on coastal food webs in the Baltic Sea area

The aim of this study was to examine top-down effects of cursorial spiders in subsidized coastal food webs. Top-down effects were examined by selectively removing cursorial spiders, mainly wolf spiders, from small islands (26–1834 m²) during 2004–2007. The removal success varied among islands and years, and spider densities were reduced by 30–65%. To examine treatment effects, arthropods were sampled using a vacuum sampling device at three occasions each summer. The densities of other arthropod predators, especially web spiders and carabids, were higher on islands where cursorial spiders had been removed compared to control islands. This treatment effect probably occurred through a combination of competitive release and reduced intraguild predation from cursorial spiders. No treatment effects were found on herbivore or detritivore densities and plant biomass. This lack of effect may either be because spiders indeed have fairly weak effects on herbivore and detritivore densities on Baltic shorelines or that the removal success of spiders was insufficient for observing such effects. Treatment effects may also be weak because negative effects exerted by spiders on herbivore and detritivore populations were balanced by increased predation by insect predators.     

Erdosteine modulates radiocontrast‐induced hepatotoxicity in rat

It has been suggested that reactive oxygen species (ROS) plays an important role in radio contrast media (RCM)‐induced ischemia reperfusion tissue injury although antioxidants may have protective effects on the injury. We investigated the effects of erdosteine as an antioxidant agent on RCM‐induced liver toxicity in rats by evaluation of lipid peroxidation (as TBARS), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GSH‐Px) values and histological evaluation. Twenty‐one rats were equally divided into three groups as follows: control, RCM, and RCM plus erdosteine. RCM was intraperitoneally administered for 1 day. Erdosteine was administered orally for 2 days after RCM administration. Liver samples were taken from the rats and they homogenized in a motor‐driven tissue homogenizer. TBARS levels were significantly (p < 0.005) higher in RCM group than in control although SOD activities significantly (p < 0.05) decreased in RCM group. TBARS levels were lower in RCM plus erdosteine group than in control although SOD activity and GSH level increased (p < 0.05) in liver as compared to RCM alone. Erdosteine showed also histopathological protection (p < 0.0001) against RCM induced hepatotoxicity. GSH‐Px and CAT activities were not statistically changed by the erdosteine. According to our results, it can be concluded that radiocontrast media can induce oxidative stress in liver as suggested by previous studies. Erdosteine seems to be protective agent on the radiocontrast media‐induced liver toxicity by inhibiting the production of ROS via the enzymatic antioxidant system. Copyright © 2009 John Wiley & Sons, Ltd.     

2D and Trap‐Assisted 2D Langevin Recombination in Polymer:Fullerene Blends

The impact of trapping on the recombination dynamics in polymer:fullerene blends is clarified using the highly ordered bulk heterojunction (BHJ) blend poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] (PBTTT) and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) at different weight ratios as a model system. The recombination dynamics are determined using both transient charge extraction and steady‐state techniques. The results show that both the decay of photogenerated charge and the light ideality factor at a polymer:fullerene weight ratio of 1:4 are fully consistent with 2D Langevin recombination; in the 1:1 case the recombination is seen to be affected by electron trapping. The theory of 2D Langevin recombination is extended to the case with high trap density in agreement with the observations in the 1:1 case. The recombination capture coefficients are derived both for trap‐assisted and band‐to‐band recombination and it can be seen that anisotropic charge transport reduces the capture coefficients in both cases resulting in a reduced overall recombination.