Multifunctional grains for the future: genetic engineering for enhanced and novel cereal quality

Cereals provide more than half the world population’s calorific intake, and have a variety of other important uses as food and beverage ingredients, livestock feeds, and as sources of renewable energy and industrial components. The technology to genetically modify many important cereals is now well-established, thereby presenting new opportunities to produce cereals with enhanced quality and novel properties. In 2007, GM (genetically modified) maize with insect and herbicide resistance was grown on over 30 million hectares worldwide, yet to date, there are no GM cereals with enhanced or novel grain (end-use) qualities being grown in commercial farmers’ fields. This review will discuss some of the latest GM technology developments reported to enhance the quality of cereals for food and other uses. Developments and opportunities involving gene manipulation for starch and protein quality, as well as non-starch polysaccharides, phenolic compounds and micronutrients will also be discussed. The current paucity of GM cereals with enhanced grain quality is not related to the absence of technological progress, rather it is the regulatory and consumer acceptance issues that have slowed the release of these crops.     

Amino acid contacts in proteins adapted to different temperatures: hydrophobic interactions and surface charges play a key role

Thermophiles, mesophiles, and psychrophiles have different amino acid frequencies in their proteins, probably because of the way the species adapt to very different temperatures in their environment. In this paper, we analyse how contacts between sidechains vary between homologous proteins from species that are adapted to different temperatures, but displaying relatively high sequence similarity. We investigate whether specific contacts between amino acids sidechains is a key factor in thermostabilisation in proteins. The dataset was divided into two subsets with optimal growth temperatures from 0–40 and 35–102°C. Comparison of homologues was made between low-temperature species and high-temperature species within each subset. We found that unspecific interactions like hydrophobic interactions in the core and solvent interactions and entropic effects at the surface, appear to be more important factors than specific contact types like salt bridges and aromatic clusters. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Consequence of omitting or adding a meal in man on body composition, food intake, and metabolism

Objective: To investigate in man the consequence on body composition and related biological and metabolic parameters of omitting or adding a meal. Research Methods and Procedures: Twenty‐four young normal‐weight male subjects were recruited, 12 usual four‐meal and 12 usual three‐meal eaters, differing only in the consumption of an afternoon meal. They omitted or added a fourth meal during a 28‐day habituation period and were asked to report their intake on three 3‐day occasions. Before and after this habituation period, subjects participated in a session with a time‐blinded procedure, and blood was collected continuously from lunch to the spontaneously requested dinner. Body composition, respiratory quotient, and biochemical parameters were measured in the late evening preceding each session. Results: Omitting a meal was followed by increases in fat mass (360 ± 115 grams, p < 0.05), late evening leptin concentration (20.7 ± 11.0%, p < 0.05), and respiratory quotient (3.7 ± 1.4%, p < 0.05). Increase in the percentage of dietary fat during the habituation period (+4.1 ± 2.0%, p < 0.05) was correlated with fat mass (r = 0.66, p < 0.05). Adding a meal had no effect, but, in both groups, the change in energy content at this fourth eating occasion was correlated with the change in adiposity. Discussion: Our results suggest that adiposity may increase when young lean male subjects switch from a four‐ to a three‐meal pattern by removing their usual afternoon meal. This effect could be partly mediated by a change in the macronutrient composition of the diet.     

k-长DNA子序列频数分布研究

在详细阐述了生成DNA序列分形图像的Hao方法后,提出一种能够直观显示k-长DNA子序列频数分布差异性的三维频数分布图生成方法。把3D频数分布图转化为1D对数频谱图,突出显示了频数分布的局部特征,提出k-长DNA子序列频数区划分准则,并详细研究了甚高频数区的n阶零间隔现象,指出n阶零间隔分布就是基因组进化过程所留痕迹的假设,并给出对数频谱图特征的生物学解释。实验发现许多DNA序列频数概率分布近似服从非中心F分布,对于分布呈多峰现象的基因组序列,可采用多个非中心F分布的叠加来拟合。在比较非中心F分布与Gamma分布后,提出一种结合二者在拟合方面具有互补优势的新分布,实验证明这种新分布能够更好地吻合实际DNA序列的频数分布。最后研究了两种特异出现频数(最高出现频数与出现频数为1的k-长子序列个数)与k值的关系,发现不同物种的这两种关系具有良好的一致性。     

Extremely low frequency electromagnetic field exposure affects fertilization outcome in swine animal model

Modern society continuously exposes the population to electromagnetic radiation, the effects of which on human health, in particular reproduction, are still unknown. The aim of this research was to assess the effect of acute (1 h) exposure of boar spermatozoa to a 50 Hz extremely low frequency electromagnetic field (ELF-EMF) on early fertility outcome. The effect of intensities ranging from 0 to 2 mT on morpho-functional integrity of capacitated spermatozoa was examined in vitro. The oviducts containing or without spermatozoa were then exposed to the minimum in vivo, TD_50, and maximum intensities determined in vitro, 4 h before ovulation. The effects of ELF-EMF on spermatozoa in terms of early embryo development were evaluated after 12 h and 6 days. It was found that in vitro ELF-EMF >0.5 mT induced a progressive acrosome damage, thus compromising the ability of spermatozoa to undergo acrosomal reaction after zona pellucida stimulation and reducing the in vitro fertilization outcome. These effects became evident at 0.75 mT and reached the plateau at 1 mT. Under in vivo conditions, the ELF-EMF intensity of 1 mT was able to compromise sperm function, significantly reducing the fertilization rate. In addition, the exposure of oviducts to fields ≥ 0.75 mT in the absence of spermatozoa was able to negatively affect early embryo development. In fact, it was found to cause a slowdown in the embryo cleavage. In conclusion, it was demonstrated how and at which intensities ELF-EMF negatively affect early fertility outcome in a highly predictive animal model.     

大叶铁线莲访花昆虫调查及盗蜜昆虫行为研究

大叶铁线莲Clematis heracleifolia DC. 的花朵大多下垂,需要传粉昆虫为其传粉,目前尚无关于其访花昆虫研究的报道。 通过2年的野外观察研究,共观察到27种昆虫访问大叶铁线莲。 发现有盗蜜行为的昆虫7种, 其中1种同时具有初级盗蜜和次级盗蜜行为,2种具有初级盗蜜行为,4种具有次级盗蜜行为;黄胸木蜂Xylocopa appendiculata Smith是主要的盗蜜昆虫,其盗蜜行为影响了其它昆虫的访花行为,对大叶铁线莲的传粉造成一定的影响。 在其余20种访花昆虫中,双带弄蝶Lobocla bifasciata (Bremer et Grey)、贡尺蛾Gonodontis aurata Prout、熊蜂Bombus sp.和姬蜂虻Systropus sp.是优势种; 而小青花金龟Oxycetonia jucunda Faldermann和日本条螽Ducetia japonica (Thunberg)访花频率最低,且访花目的只是取食花朵。 通过对大叶铁线莲访花昆虫的调查和盗蜜昆虫行为的研究,为大叶铁线莲的传粉生物学和保护提供参考依据。     

NEGATIVE FREQUENCY‐DEPENDENT SELECTION IN FEMALE COLOR POLYMORPHISM OF A DAMSELFLY

Negative frequency‐dependent selection (NFDS) is one of the most powerful selective forces maintaining genetic polymorphisms in nature. Recently many prospective cases of polymorphisms by NFDS have been reported. Some of them are very complicated, although strongly supportive of the NFDS. Here we investigate NFDS in wild populations of the dimorphic damselfly Ischnura senegalensis, in which females occur as andromorphs and gynomorphs. Specifically, we (1) test fitness responses to morph frequencies, (2) built a simple population genetic model, and (3) compare the observed and predicted morph‐frequency dynamics. Fitnesses of the two morphs are an inverse function of its own frequency in a population, and are about equal when their frequencies are similar. Thus the conditions necessary for NFDS are satisfied. The long‐term field surveys show that the morph frequencies oscillate with a period of two generations. Morph frequencies in a small population undergo large oscillations whereas those in a large population do small oscillations. The demographic properties of the observed dynamics agree well with those of our model. This example is one of the simplest confirmed cases of NFDS maintaining genetic polymorphisms in nature.     

A high-accuracy protein structural class prediction algorithm using predicted secondary structural information

One major problem with the existing algorithm for the prediction of protein structural classes is low accuracies for proteins from α/β and α+β classes. In this study, three novel features were rationally designed to model the differences between proteins from these two classes. In combination with other rational designed features, an 11-dimensional vector prediction method was proposed. By means of this method, the overall prediction accuracy based on 25PDB dataset was 1.5% higher than the previous best-performing method, MODAS. Furthermore, the prediction accuracy for proteins from α+β class based on 25PDB dataset was 5% higher than the previous best-performing method, SCPRED. The prediction accuracies obtained with the D675 and FC699 datasets were also improved.     

Selection for individual recognition and the evolution of polymorphic identity signals in Polistes paper wasps

Individual recognition (IR) requires individuals to uniquely identify their social partners based on phenotypic variation. Because IR is so specific, distinctive phenotypes that stand out from the crowd facilitate efficient recognition. Over time, the benefits of unique appearances are predicted to produce a correlation between IR and phenotypic variation. Here, we test whether there is an association between elevated phenotypic polymorphism and IR in paper wasps. Previous work has shown that Polistes fuscatus use variable colour patterns for IR. We test whether two less variable wasp species, Polistes dominulus and Polistes metricus, are capable of IR. As predicted, neither species is capable of IR, suggesting that highly variable colour patterns are confined to Polistes species with IR. This association suggests that elevated phenotypic variation in taxa with IR may be the result of selection for identity signals rather than neutral processes. Given that IR is widespread among social taxa, selection for identity signalling may be an underappreciated mechanism for the origin and maintenance of polymorphism.     

Pollinator shifts and the loss of style polymorphism in Narcissus papyraceus (Amaryllidaceae)

Darwin proposed that the driving force for the evolution of style polymorphisms is the promotion of cross‐pollination between style morphs, through accurate placement of pollen on the pollinator’s body. This hypothesis has received much attention, but the effect of different pollinators in the fitness of morphs remains poorly understood. Narcissus papyraceus is a style dimorphic species (long ‐L‐ and short ‐S‐ styled) with isoplethic (1 : 1) and L‐monomorphic populations, mainly visited by long‐tongued (LT) nocturnal and short‐tongued (ST) diurnal pollinators, respectively. We studied natural female fertility of morphs, and assessed the role of diurnal and nocturnal pollinators. We also quantified female fertility of the morphs in experimental populations with different morph ratio, exposed to predominately long‐ or short‐tongued pollinators. We found that with LT pollinators, both morphs were successfully pollinated in all morph ratio conditions, suggesting that these insects could be involved in maintenance of the polymorphism, although other factors may also play a role. However, with ST pollinators, S‐plants displayed less fertility than L‐plants, and mating among L‐plants was favoured, implying that the polymorphism is lost. These results underscore the role of pollinators on variations in style polymorphism.