Role of H+-ATPase and Alternative Oxidase in Regulation of Intracellular pH at Different Stages of Development of the Tobacco Male Gametophyte

In order to determine the role of the plasma membrane H⁺-ATPase and alternative oxidase (alternative pathway of respiration) in the regulation of intracellular pH during development of the tobacco male gametophyte, we studied the changes in pH due to the inhibition of these enzymes by orthovadanate and benzhydroxamic acid, respectively. The inhibition of these enzymes decreased the intracellular pH at all three studied stages of the male gametophyte development: middle and late binuclear pollen grains and activated mature pollen grain. The data obtained suggest that H⁺-ATPase and alternative oxidase are involved in the regulation of intracellular pH of the pollen grain during its differentiation and activation that precede germination. At the same time, during the recovery of intracellular pH after its acidification by propionic acid, it was found that other mechanisms, not related to the above mentioned, greatly contribute to the regulation of pH.     

小麦开花后旗叶中蔗糖合成与籽粒中蔗糖降解

在小麦开花后,旗叶中蔗糖磷酸合成酶（SPS）活性在开花后14d内一直维持较高水平,蔗糖合成酶（SS）的活性在开花后14-28d较高,蔗糖的含量与SPS活性呈显著正相关,籽粒中蔗糖合成酶（SS）在开花后28d内一直维持较高的活性;与此相对应,籽粒蔗糖的含量在开花后28d内呈明显的下降趋势。而旗叶和籽粒中SS活性均与籽粒淀粉的积累速率呈极显著正相关。     

来自山羊草的杀配子染色体(Aegilops cylindryca 2C)对小黑麦减数分裂及花粉粒有丝分裂过程的影响

用来自柱穗山羊草的杀配子染色体2C,诱导六倍体、八倍体小黑麦染色体的断裂,观察杂种F1的减数分裂行为,在PMCI及PMCII后期观察到了大量的落后染色体、染色体断片、环状染色体及桥,在二分了解子及四分孢子中有为数甚多的、大小不一的微核,有的还形成多分孢子。在对F1花粉粒的有丝分裂观察中,未见分裂异常。由此推断杀配子染以体诱导染色体断裂可能不发生在配子形成的有丝分裂过程。这与巳有的报道不同。     

Characterization of sunlight-grown transgenic rice plants expressing Arabidopsis phytochrome A

Transgenic rice (Oryza sativa) overexpressing Arabidopsis phytochrome A (phyA) was cultivated up to the T₃ generation in paddy to elucidate the role of phyA in determining the plant architecture and the productivity of sunlight-grown rice plants. PhyA is light-labile and controls plant growth in response to the far-red light-dependent high-irradiance response as well as the very low fluence response. The Arabidopsis phyA gene linked to the rice rbcS promoter was transformed into embryogenic rice calli, and the calli were regenerated to whole plants. Compared to wild-type seedlings, the rbcS::PHYA transgenic seedlings contained more phyA when grown in the dark, and at least 10-fold more phyA when exposed to white light. When grown in paddy, the phyA transgenic plants in general exhibited reduced plant height (dwarfing), larger grain size, higher chlorophyll content, smaller tiller number, and low grain fertility compared to wild-type plants. The heading stage was not significantly changed. However, it is likely that a certain level of phyA is a prerequisite for induction of such changes. It is suggested that phyA overproduction in rice could be a useful tool to improve rice grain productivity by the larger grain size that increases grain yield and the dwarfing that tolerates lodging-associated damage.     

Interaction between organophosphate insecticides and the parasitic mite Acarophenax lacunatus (Prostigmata: Acarophenacidae) on Rhyzopertha dominica (Coleoptera: Bostrichidae)

The interaction between the organophosphate insecticides fenitrothion and pirimiphos-methyl with Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae), an egg parasite of the stored grain pest Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), was assessed in a range of doses for each compound. The number of physogastric females of A. lacunatus and egg parasitism (%) decreased with increasing insecticide doses and mite density for both organophosphates. Lower insecticide doses for fenitrothion and pirimiphos-methyl and lower mite densities led to higher instantaneous rates of increase of the mite population. Overall lower instantaneous rates of increase of A. lacunatus were obtained with the insecticide pirimiphos-methyl. The sustained presence of the mite species in all insecticide doses suggest that this biological control agent may be used together with insecticide applications for controlling R. dominica, but high insecticide doses, mainly of pirimiphos-methyl, compromise mite population growth. The high rates of egg parasitism obtained with the biological control agent may aid the insecticide effect on the adult pest population preventing its outbreaks in wheat grains, constituting a potential tactic for pest management of stored wheat.     

Detecting and quantifying meat meal or meat and bone meal contamination in fishmeal by visible and near infrared reflectance spectra

The use of animal protein feeds such as meat meal or meat and bone meal (MMBM) play an important role in the feed manufacturing industry, but their safe and healthy use in animal feeds is of public concern in order to prevent the spread of bovine spongiform encephalopathy (BSE). The objective of the present work was to develop a technique using near infrared reflectance spectroscopy (NIRS) that would be suitable for detecting and quantifying contaminating levels of MMBM in fishmeal. To this end, a partial least squares (PLS) discriminant analysis and a modified partial least squares (MPLS) quantitative analysis, using visible and NIRS, were developed using a calibration set of 186 samples including 90 samples of pure fishmeal and 96 samples adulterated with MMBM at levels ranging from 10 to 320 g/kg. An external validation set, comprised of 39 pure samples and 54 adulterated samples, was used to validate the calibration model. A PLS discriminant analysis model developed with mathematic pretreatment 1,4,4,1, successfully detected fishmeal adulterated with MMBM. External validation indicated that all samples were discriminated correctly. A MPLS quantitative model, developed with mathematic pretreatment 1,4,4,1, also successfully predicted the MMBM in fishmeal with standard error of cross-validation (SECV) of 27.89 g/kg and ratio of the standard deviation of the validation set to the standard error of prediction (RPD) of 3.37. The calibration and validation results confirm that NIRS could provide the feed industry and inspection bodies with a rapid, non-destructive and non-invasive technique for the detection and quantification of MMBM in fishmeal.     

Effects of whole wheat feeding on the development of the digestive tract of broiler chickens

The objective of the current study was to investigate the impact of including whole wheat in broiler diets on the development of the digestive tract. Chickens were fed a standard feed containing 400 g ground wheat/kg or the same diet with a part of the wheat given separately as whole grains that increased progressively from 200 g/kg at 8 d to 400 g/kg at 22 d. Every week, from 16 to 44 d, growth performance, modifications of the size of the digestive tract organs and intestinal enzyme activities were investigated. Morphology of villi and crypts in the small intestinal segments (duodenum, jejunum, ileum) were analyzed at 23 and 44 d. Microbacterial counts were performed in jejunal, ileal and caecal contents weekly from 16 to 44 d.During the adaptation period from 8 to 15 d, the birds fed the whole wheat diet had lower feed intake and lower weight gain. Thereafter, they showed improved growth performance so that by the end of the experiment, they had higher body weight compared to the standard-fed birds, 2430 ± 29 versus 2331 ± 36 g.Higher relative weights of gizzard (+26%) and pancreas (+12%) were observed from 16 to 44 d for whole wheat-fed birds compared to standard-fed birds. No differences in relative size of the different intestinal segments were observed, except that the jejunum was shorter. Increased villus to crypt length and surface ratios were observed at 23 d in the duodenum of whole wheat-fed birds, with no differences in morphometry between groups thereafter. Alkaline phosphatase activity was higher from 16 to 44 d in the duodenum and jejunum of whole wheat-fed birds. However, the activities of the digestive enzymes, leucine aminopeptidase and maltase, were similar between the two diets in the measured intestinal segments.A lower number of facultative anaerobic bacteria was found in the ileum of the whole wheat-fed birds, with no differences between treatments for Escherichia coli and for Lactobacillus counts. In the jejunum and the caeca, no differences in microflora counts were observed.The present results showed that feeding whole grains to broilers led mainly to modifications in the upper part of the digestive tract (gizzard, pancreas) and had little influence on the small and large intestine.     

Effects of CO2 enrichment on soluble amino acids and organic acids in barley primary leaves as a function of age, photoperiod and chlorosis

Responses of soluble amino acids and organic acids to either ambient (36 Pa) or elevated (100 Pa) CO₂ treatments were determined using barley primary leaves (Hordeum vulgare L. cv. Brant). Total soluble amino acids were increased 33% by CO₂ enrichment 9 days after sowing (DAS), but a decrease relative to the ambient CO₂ treatment was observed with increasing leaf age. Marked declines of glutamine and asparagine were observed under CO₂ enrichment, both diurnally and with advancing leaf age. Consequently, total soluble amino acids were 59% lower in the elevated compared to the ambient CO₂ treatment 17 DAS. It was likely that chlorosis in response to CO₂ enrichment negatively impacted soluble amino acid levels in older barley primary leaves. In contrast to the ambient CO₂ treatment, glutamine and most other soluble amino acids decreased as much as 60% during the latter half of a 12 h photoperiod in primary leaves of 13-day-old seedlings grown under enhanced CO₂. Malate was decreased about 9 percent by CO₂ enrichment and citrate and succinate were increased by similar amounts when measured 9 and 13 DAS. Malate accumulation was also decreased about 20% by CO₂ enrichment on a diurnal basis. The onset of CO₂-dependent leaf yellowing had much less of an effect on organic acids than on soluble amino acids. This above results emphasized the sensitivity of N metabolism to CO₂ enrichment in barley. Increased levels of citrate and succinate in response to CO₂ enrichment suggested that the tricarboxylic acid cycle was upregulated in barley by CO₂ enrichment. In summary, organic and amino acid levels in barley primary leaves were dynamic and were altered by age, diurnally and in response to CO₂ enrichment.     

Effect of storage xyloglucans on peritoneal macrophages

Xyloglucans from seeds of Copaifera langsdorffii (XGC), Hymenaea courbaril (XGJ) and Mucuna sloanei (XGM) were obtained from milled and defatted cotyledons by aqueous extraction at 25 degrees C. The resulting fractions contained Glc, Xyl and Gal in molar ratios of 2.5: 1.5: 1.0 (XGC), 3.8: 2.6: 1.0 (XGJ) and 2.5: 1.6: 1.0 (XGM). HPSEC-MALLS/RI analysis showed that each polysaccharide fraction was homogeneous; M(w) values were 1.6 x 10(5), 2.0 x 10(5) and 1.5 x 10(5)g/mol, respectively. The effect of the xyloglucans on the production of O(2)*(-) and NO* and on the recruitment of macrophages to the mouse peritoneum was evaluated. All polysaccharides promoted an increase in the number of peritoneal macrophages in a dose-dependent manner. The largest increase, of 576% in comparison to the control group, was elicited by XGJ at 200 mg/kg. The effect of XGC, XGJ and XGM on O(2)*(-) production, in the presence or absence of phorbol 12-myristate 13-acetate (PMA), was not statistically significant. For NO(.) production, the lowest concentration of XGC (10 microg/ml) gave rise to an increase of 262% when compared to the control group; the effect was dose-dependent, reaching 307% at 50 microg/ml. On the other hand, XGJ at a concentration of 50 microg/ml enhanced NO* production by 92%. XGM did not affect NO* production significantly. The results indicate that xyloglucans from C. langsdorffii, H. courbaril and M. sloanei have immunomodulatory activity.     

Leaf area estimation by simple measurements and evaluation of leaf area prediction models in Cabernet-Sauvignon grapevine leaves

For two growing seasons (2005 and 2006), leaves of grapevine cv. Cabernet-Sauvignon were collected at three growth stages (bunch closure, veraison, and ripeness) from 10-year-old vines grafted on 1103 Paulsen and SO4 rootstocks and subjected to three watering regimes in a commercial vineyard in central Greece. Leaf shape parameters (leaf area-LA, perimeter-Per, maximum midvein length-L, maximum width-W, and average radial-AR) were determined using an image analysis system. Leaf morphology was affected by sampling time but not by year, rootstock, or irrigation treatment. The rootstock×irrigation×sampling time interaction was significant for all the leaf shape parameters (LA, Per, L, W, and AR) and the means of the interaction were used to establish relationships between them. A highly significant linear function between L and LA could be used as a non-destructive LA prediction model for Cabernet-Sauvignon. Eleven models proposed for the non-destructive LA estimation in various grapevine cultivars were evaluated for their accuracy in predicting LA in this cultivar. For all the models, highly significant linear functions were found between calculated and measured LA. Based on r ² and the mean square deviation (MSD), the model proposed for LA estimation in cv. Cencibel [LA = 0.587(L×W)] was the most appropriate.