Variation in sugar levels and invertase activity in mature fruit representing a broad spectrum of Cucumis melo genotypes

Sugar accumulation is a very important physiological process that determines dessert-melon fruit quality. Considerable variation in the sugar content and composition in the mature flesh of Cucumis melo L. fruits was observed among 56 genotypes which represent the wide range of morphological and horticultural types found in this species. Sucrose accumulation was observed not only among 'dessert melons' of the inodorus and cantalupensis types, but also in representatives of other subgroups of C. melo, including some of the accessions from agrestis and conomon groups. Among the genotypes that accumulate sucrose, the levels of this sugar, and not of the hexoses, were correlated with the total sugar concentration. Hexose levels were correlated with total sugar levels only among low-sugar genotypes that did not accumulate sucrose. Activities of the sucrose hydrolyzing enzymes acid invertase (EC 3.2.1.26) and alkaline invertase (EC 3.2.1.27) were measured in the mature fruit flesh and the results of this survey support the hypothesis that low acid invertase activity is a prerequisite for sucrose accumulation. The sucrose accumulating, high sugar genotypes had less-acidic flesh pH values (pH> 6) than the low-sugar genotypes. The latter were characterized by a broader range of pH values, including acidic (pH< 5.5) fruit flesh.     

Ovicidal and larvicidal effectiveness of insecticides applied by dipping apples on the small fruit tortrix Grapholita lobarzewskii

The larvicidal and ovicidal effectiveness of twelve insecticides on Grapholita lobarzewskii Nowicki was tested by dipping apples in different concentrations of the insecticides. Emamectin was the most effective larvicidal product, with an LC(50) of 0.01 mg kg(-1), closely followed by spinosad, methoxyfenozide and chlorpyrifos-methyl, with LC(50) values between 0.2 and 0.7 mg kg(-1). Products like imidacloprid, indoxacarb, phosmet and thiacloprid gave LC(50) values between 1 and 2 mg kg(-1). Lastly, chlorpyrifos-ethyl and phosalone had LC(50) values of around 4 mg kg(-1), whereas tebufenozide and diflubenzuron had almost no larvicidal effect. Most of the products tested had low ovicidal effectiveness, and only fenoxycarb and emamectin gave LC(50) values worthy of note, close to 2 mg kg(-1).     

Comment on "Phonemic diversity supports a serial founder effect model of language expansion from Africa"

We show that Atkinson's (Reports, 15 April 2011, p. 346) intriguing proposal--that global linguistic diversity supports a single language origin in Africa--is an artifact of using suboptimal data, biased methodology, and unjustified assumptions. We criticize his approach using more suitable data, and we additionally provide new results suggesting a more complex scenario for the emergence of global linguistic diversity.     

Can denaturing gradient gel electrophoresis (DGGE) analysis of amplified 16s rDNA of soil bacterial populations be used in forensic investigations?

In criminal investigations, information on the origin of soils may be crucial for solving cases. The biological complexity of soil may potentially be used for sorting and differentiating between soil samples. Nucleic-acid based analyses of soil microbial populations are powerful tools, routinely used in studies of this habitat. Application of such approaches in forensics implies that a standardized DNA extraction method has to be applied to all samples. In this study, several DNA extraction protocols were compared. An improvement on the method proposed by Tsai and Olson (1991) was found to be most suited to extract DNA from various soil types, including from small samples. A blind test on soils from a crime, an alibi scene and unrelated locations was conducted to evaluate the potential of environmental PCR and denaturating gradient gel electrophoresis for use in forensic science. In most cases, soil patterns clustered according to soil type and location.     

Intermittent warming of peaches reduces chilling injury by enhancing ethylene production and enzymes mediated by ethylene

SUMMARY

Peaches (Prunus persica ‘Hermoza’) were ripened at 208>C after harvest and either stored at 08C for four weeks (control) to induce chilling injury or given intermittent warming (IW) on the twelfth day of storage (28C for 24.h) to alleviate chilling injury (CI). Continuously stored fruit from control developed wo olliness, a CI disorder, during ripening at 208C after cold storage while only a small percentage of IW fruit developed woolliness. CI fruit produced less ethylene during ripening after storage, and this inhibited ethylene production was closely tied with woolliness development. The IW treatment caused enhanced ethylene production in the fruit when returned to 08C and the ethylene remained higher than control fruit until the end of the storage period. IW also induced the messages for 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) and 1-aminocyclopropane-1-carboxylic acid synthase (ACS) in the ethylene synthesis pathway. IW also elevated the mRNA of the cell wall degrading enzymes polygalacturonase (PG) and endo-1,4-gluconase (EGase). The mRNAs of the cell wall enzymes and the enzymes in the ethylene synthesis pathway remained higher even after 5.d at 08 C following the IW treatment. It is suggested that IW maintained the fruit tissue capacity to ripen normally by preventing inhibition of the ethylene synthesis pathway which occurred in the control fruit after extended storage.     

转变经营方式优化资源利用推动草地畜牧业改革和发展

草地畜牧业发展不能以草地退化为代价,以草定畜、依法治草势在必行.改革经营方.式发展草地农业,优化资源利用,是推动草地畜牧业改革和发展的有效途径.