Carbon isotopic composition, gas exchange, and growth of three populations of ponderosa pine differing in drought tolerance

Effects of water supply on gas exchange, carbon isotopic composition, and relative growth rate were compared among seedlings from three populations of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) grown in a controlled environment chamber. The three populations were chosen to represent high, moderate and low drought tolerance. There was no indication that drought tolerance was related to high water-use efficiency. Populations differed (P < 0.05) in relative growth rate (RGR), but did not differ (P > 0.10) in gas exchange variables or carbon isotope ratio (delta(13)C). Well-watered seedlings had significantly higher RGR, xylem pressure potential (Psi(xpp)), net photosynthesis (A), stomatal conductance to water vapor (g), and lower delta(13)C and instantaneous water-use efficiency than water-stressed seedlings. With decreasing Psi(xpp), A decreased linearly, whereas g decreased exponentially. Seedlings of the highly drought-tolerant population were more sensitive to water availability than seedlings from the other populations; they used water quickly when water was available, but closed their stomata in response to water stress. We conclude that, in ponderosa pine, the drought avoidance mechanism is more important for survival and growth in arid and semiarid environments than the efficient use of water.     

Phylogeny of Fusarium oxysporum f. sp. lactucae Inferred from Mitochondrial Small Subunit, Elongation Factor 1-alpha, and Nuclear Ribosomal Intergenic Spacer Sequence Data

ABSTRACT Fusarium oxysporum f. sp. lactucae, causal agent of Fusarium wilt of lettuce, is a serious pathogen recently reported in Arizona. Sequence analysis of the mitochondrial small subunit (mtSSU), translation elongation factor 1-alpha (EF-1alpha) gene, and the nuclear ribosomal DNA intergenic spacer (IGS) region was conducted to resolve relationships among f. sp. lactucae isolates, F. oxysporum isolates from other hosts, and local non-pathogenic isolates. Analysis of mtSSU sequences provided limited phylogenetic resolution and did not differentiate the lactucae isolates from 13 other F. oxysporum isolates. Analysis of EF-1alpha sequences resulted in moderate resolution, grouping seven formae speciales with the lactucae isolates. Analysis of the IGS region revealed numerous sequence polymorphisms among F. oxysporum formae speciales consisting of insertions, deletions, and single nucleotide transitions and substitutions. Repeat sequence analysis revealed several duplicated subrepeat units that were distributed across much of the region. Based on analysis of the IGS sequence data, lactucae race 1 isolates resolved as a monophyletic group with three other formae speciales of F. oxysporum. In all analyses, lactucae race 2 isolates composed a separate lineage that was phylo-genetically distinct and distantly related to the lactucae race 1 isolates.     

玉米大斑病防治研究与探讨

<正>1、试验目的1.1通过田间试验,掌握玉米大小斑病、顶腐病发生时期、发生规律。筛选出防治玉米大斑病、的高效优质药剂。2、试验2.1试验药剂70%恶霉灵可湿粉京博农化科技股份有限公司生产50%多菌灵威海韩孚生化药业有限公司生产70%甲基硫菌灵威海韩孚生化药业有限公司生产75%百菌清威海韩孚生化药业有限公司生产3、试验地点及品种试验地点、农业中心试验地,品种银河126。4、试验设计4.1玉米大斑病防治     

Comparison of immune responses in parenteral FaeG DNA primed pigs boosted orally with F4 protein or reimmunized with the DNA vaccine

We previously showed that an intradermal (i.d.) FaeG DNA prime (2x)-oral F4 protein boost immunization induces a systemic response and weakly primes a mucosal IgG response in pigs, especially when plasmid vectors encoding the A and B subunit of the E. coli thermo-labile enterotoxin (LT) are added to the DNA vaccine. In the present study, we evaluated whether addition of 1alpha,25-dihydroxyvitamin D(3) (vitD(3)) to the DNA vaccine could further enhance this mucosal priming and/or modulate the antibody response towards IgA. To further clarify priming of systemic and mucosal responses by the i.d. DNA vaccination, we firstly compared the localization of the F4-specific antibody response in pigs that were orally boosted with F4 to that in pigs that received a third i.d. DNA immunization and secondly evaluated cytokine mRNA expression profiles after i.d. DNA vaccination. The i.d. DNA prime (2x)-oral F4 boost immunization as well as the 3 i.d. DNA vaccinations induced mainly a systemic response, with a higher response observed following the heterologous protocol. Co-administration of vitD(3), and especially of the LT vectors, enhanced this response. Furthermore, only the heterologous immunization resulted in a weak mucosal priming, which appeared to require the presence of the LT vectors or vitD(3) as adjuvants. In addition, the LT vectors strongly enhanced the FaeG-specific lymphocyte proliferation and this was accompanied by the absence of a clear IL-10 response. However, despite two DNA immunizations in the presence of these adjuvants and an oral F4 boost, we failed to demonstrate the secretory IgA response needed to be protective against enterotoxigenic E. coli.     

Diterpenes from Salvia broussonetii transformed roots and their insecticidal activity

The new diterpenes brussonol (1) and iguestol (6alpha,11-dihydroxy-12-methoxy-abieta-8,11,13-triene) (2) with an icetexane and a dehydroabietane skeleton, respectively, have been isolated from hairy root cultures of Salvia broussonetii. Other previously known diterpenes, 7-oxodehydroabietane, 11-hydroxy-12-methoxyabietatriene, taxodione, inuroyleanol, ferruginol, deoxocarnosol 12-methyl ether, cryptojaponol, pisiferal, sugiol, isomanool, 14-deoxycoleon U, 6alpha-hydroxydemethylcryptojaponol, demethylsalvicanol, and demethylcryptojaponol, were also obtained from these roots. The insect antifeedant and toxic effects of several of these compounds were investigated against the insect pests Spodoptera littoralis and Leptinotarsa decemlineata. Additionally, their comparative cytotoxic effects were tested on insect Sf9 and mammalian CHO cells. Demethylsalvicanol (4) was a moderate antifeedant to L. decemlineata, whereas brussonol (1) was inactive. 14-Deoxycoleon U (15) was the strongest antifeedant, whereas demethylcryptojaponol (11) was toxic to this insect. None of these compounds had antifeedant or negative effects on S. littoralis ingestion or weight gains after oral administration. Demethylcryptojaponol (11) was cytotoxic to mammalian CHO and insect Sf9 cell lines, followed by the icetexane derivative brussonol (1), with moderate cytotoxicity in both cases. The remainder of the test compounds showed a strong selective cytotoxicty to insect Sf9 cells, with demethylsalvicanol (4) being the most active.     

Tyrosine cross-links: molecular basis of gluten structure and function

The formation of the large protein structure known as "gluten" during dough-mixing and bread-making processes is extremely complex. It has been established that a specific subset of the proteins comprising gluten, the glutenin subunits, directly affects dough formation and breadmaking quality. Glutenin subunits have no definitive structural differences that can be directly correlated to their ability to form gluten and affect dough formation or breadmaking quality. Many protein structural studies, as well as mixing and baking studies, have postulated that disulfide bonds are present in the gluten structure and contribute to the process of dough formation through the process of disulfide-sulfhydryl exchange. Evidence presented here indicates that tyrosine bonds form in wheat doughs during the processes of mixing and baking, contributing to the structure of the gluten network. The relative contributions of tyrosine bonds and disulfide--sulfhydryl interchange are discussed.     

Free amino acid composition of quince (Cydonia oblonga Miller) fruit (pulp and peel) and jam

Twenty-one free amino acids present in several samples of quince fruit (pulp and peel) and quince jam (homemade and industrially manufactured) were analyzed by GC/FID. The analyses showed some differences between quince pulps and peels. Generally, the highest content in total free amino acids and in glycine was found in peels. As a general rule, the three major free amino acids detected in pulps were aspartic acid, asparagine, and hydroxyproline. For quince peels, usually, the three most abundant amino acids were glycine, aspartic acid, and asparagine. Similarly, for quince jams the most important free amino acids were aspartic acid, asparagine, and glycine or hydroxyproline. This study suggests that the free amino acid analysis can be useful for the evaluation of quince jam authenticity. It seems that glycine percentage can be used for the detection of quince peel addition while high alanine content can be related to pear addition.     

The nutritional status of asymptomatic HIV-infected Africans: directions for dietary intervention?

OBJECTIVE: To compare the relationships between food (nutrient) intakes and biochemical markers of nutritional status of asymptomatic HIV-infected with HIV-uninfected subjects, to gain more information on the appropriate diet for HIV-infected persons at an early stage of infection. DESIGN: Cross-sectional population-based survey. SETTING: North West Province, South Africa. SUBJECTS: Two hundred and sixteen asymptomatic HIV-infected and 1550 HIV-uninfected men and women volunteers aged 15 years and older, recruited as 'apparently healthy' subjects from 37 randomly selected sites. OUTCOME MEASURES: Food and nutrient intakes, measured with a validated food-frequency questionnaire, and nutritional status indicated by anthropometric and biochemical variables, measured by a standardised methodology. RESULTS: The prevalence of HIV infection in the study population was 11.9%. The anthropometric indices and nutrient intakes of HIV-infected and uninfected subjects did not differ significantly, indicating that these 216 HIV-infected subjects were at an early stage of infection. Of the biochemical nutritional status variables, high-density lipoprotein cholesterol and total cholesterol, haemoglobin, albumin and triglycerides were significantly lower in infected subjects. They also had higher globulin and liver enzyme levels than uninfected subjects. In infected subjects, serum albumin correlated significantly with serum lipids, serum vitamin A, serum vitamin E, serum iron, total iron-binding capacity and haemoglobin. The significant positive correlations of the liver enzymes with serum lipids, albumin, vitamin A and iron, observed in HIV-uninfected subjects, disappeared in the infected subjects. Polyunsaturated fat intake showed significant positive correlations with the increased liver enzymes in infected subjects. A principal components analysis indicated that, in infected subjects, increased liver enzymes correlated with higher consumption of maize meal and lower consumption of meat and vegetables. CONCLUSIONS AND RECOMMENDATIONS: This survey indicated that asymptomatic HIV-infected subjects who followed a diet rich in animal foods had smaller decreases in serum albumin, haemoglobin and lipid variables, and smaller increases in liver enzymes, than those who consumed a diet based on staple foods. This suggests that animal foods are associated with improved nutritional status in HIV-infected persons. These results should be confirmed with intervention studies before dietary recommendations for asymptomatic HIV-infected individuals can be made.