Dressed to impress: breeding plumage as a reliable signal of innate immunity

Animal signals involved in sexual selection are often indicators of individual quality. The assumption that sexual characters such as breeding plumage may indicate immune state has rarely been tested in free‐living migratory birds, particularly in relation to innate immunity. If sexual characters indeed reflect immune condition, then these could be used to evaluate individual quality. Melanin is a common pigment used in animal communication that mitigates the effects of oxidative stress and has positive effects on energy homeostasis, important functions during the strenuous activity of long‐distance flights. However, melanin is also immunosuppressive, and the melanised patches of breeding plumage may to some extent compromise immune responsiveness. We studied melanin‐based secondary sexual characters (SSC) in a long‐distance migratory wader, the black‐tailed godwit Limosa limosa, and found that breeding plumage features of male and female godwits are linked to components of innate immunity. Males with a larger colour extension had higher circulating levels of haptoglobin and hemolysis activity, while they also presented a lower body condition; whereas females presented a negative trend between colour and bar extension and hemolysis activity, and a positive trend for natural antibodies. The association between signal, immune state and physical condition in males suggests a cost for signal production and immune condition during prenuptial migration. Sex differences in how signals relate with immune capacity are a likely consequence of sex‐specific signalling roles and energy demands. Our results indicate that male godwit breeding plumage reflects innate immunity state, and is therefore a likely signal for females to use during mate choice as an honest indicator of male's capacity to allocate energy/resources to both expensive traits during periods of energetic constraint.     

Salinity imposed stress on principal cereal crops and employing seed priming as a sustainable management approach

Cereal crops specifically maize, wheat, and rice have a prominent role in feeding the world's population. In the context of a growing population and a potential increase in food demand in coming years, yield output of cereals is certainly necessary. Concurrently, the production of these crops is challenged with several abiotic and biotic stresses. Salinity, a leading abiotic stress in global agriculture, significantly reduce growth, yield and overall production of cereals and if not managed through successive efforts, global food security will be uncertain in the future. Thus, employment of sustainable approaches in achieving the targets of food demands of increasing population needs focused attention. Integration of agronomic and biotechnological methods can manage salinity induced drastic effects on crops which would lead to increased crop productivity. In this review, we focus on employing seed priming techniques as possible salt stress management approaches in three major cereal crops (maize, rice, and wheat).     

Dressed for sex: red as a female sexual signal in humans

Background

In many non-human primate species, a display of red by a female serves as a sexual signal to attract male conspecifics. Red is associated with sex and romance in humans, and women convey their sexual interest to men through a variety of verbal, postural, and behavioral means. In the present research, we investigate whether female red ornamentation in non-human primates has a human analog, whereby women use a behavioral display of red to signal their sexual interest to men.

Methodology/Principal Findings

Three studies tested the hypothesis that women use red clothing to communicate sexual interest to men in profile pictures on dating websites. In Study 1, women who imagined being interested in casual sex were more likely to display red (but not other colors) on their anticipated web profile picture. In Study 2, women who indicated interest in casual sex were more likely to prominently display red (but not other colors) on their actual web profile picture. In Study 3, women on a website dedicated to facilitating casual sexual relationships were more likely to prominently exhibit red (but not other colors) than women on a website dedicated to facilitating marital relationships.

Conclusions/Significance

These results establish a provocative parallel between women and non-human female primates in red signal coloration in the mating game. This research shows, for the first time, a functional use of color in women''s sexual self-presentation, and highlights the need to extend research on color beyond physics, physiology, and preference to psychological functioning.     

Rice as a model for cereal genomics.

Over the past two years, selected regions of the rice genome have been sequenced and shown to be colinear at the sequence level with limited regions of other cereal genomes. A large number of expressed gene sequences and molecular markers have accumulated in the public databases. Large insert clone libraries of the rice genome have been constructed, and rice has become an increasingly attractive candidate for whole genome sequencing.     

Unusual features of cereal seed protein structure and evolution

The alcohol-soluble (prolamin) storage proteins of barley, wheat and rye vary in their structures, but all have two features in common: the presence of distinct structural domains differing in amino acid compositions, and of repeats within one of these domains. Detailed comparisons of amino acid sequences show that all appear to have evolved from a single ancestral gene consisting of three short related regions (called A, B and C). Regions related to A, B and C are also present in the minor prolamins of maize and in three other groups of seed proteins: inhibitors of alpha-amylase and/or trypsin from cereals. 25 storage globulins from several dicotyledonous species and a 2S albumin from sunflower. It is suggested that these proteins together constitute a protein superfamily with limited sequence homology.     

The ecology and economics of damage to Brassicae by wood-pigeons Columba palumbus

Damage caused by wood-pigeons, Columba palumbus, to spring cabbage and Brussels sprouts was measured during three winters in two areas in the Vale of Evesham, Worcestershire. In one area (experimental) special attempts were made to reduce pigeon damage in addition to the normal efforts of the growers. In the other (control) area no such additional measures were taken. There was slightly more damage in 1969-70, but low market prices made it less important than in 1968-9 or 1970-1. There was no significant difference in any season between the damage in the control and experimental areas. No damage was caused to Brussels-sprout buttons as the birds ate only the tops of the plants; they preferred Brussels sprouts to cabbages and it is likely that the presence of the former helped to reduce the amount of damage to nearby cabbage fields. The amount of damage was not correlated with the amount spent on crop protection; actual damage was not correlated with the grower's estimates in the control area. In the second season a very intensive shooting campaign in the experimental area did not result in less damage, but the movements of local inhabitants and farm workers near a village did afford protection. The significance of the damage in the Vale and elsewhere is assessed in relation to the economics of crop production, the cropping pattern for cabbages and the behaviour and ecology of the wood-pigeon.     

Chemical treatment of cereal seed in relation to plant vigour and control of soil fungi

Treating oat seeds not contaminated with any known pathogen of this crop with an organo-mercury preparation (Ceresan) increased seedling vigour only when they were grown in natural or simulated winter conditions with periods of frost. This beneficial effect on vigour was largely confined to seedlings and young plants. The fungicide protected the mesocotyls from contamination or invasion by certain soil-borne fungi normally regarded as saprophytes. Cylindrocarpon radicicola and Fusarium sambucinum were closely associated with discoloured mesocotyls bearing lesions and reduced vigour of untreated plants. Protection from such fungi enabled mesocotyls to grow thicker, and, when seedlings were grown in unsterilised soil and exposed to frost, reduced the number with lesions or discolouration. Thus the ability of the saprophytic soil-borne fungi to cause damage seems to be influenced by environmental conditions.     

A conformational study of a glutamine- and proline-rich cereal seed protein, C hordein.

A combination of c.d. spectroscopy and computer prediction is used to show that C hordein has an unusual secondary structure with an absence of alpha-helix and beta-sheet, but the presence of regularly repeated beta-turns. This is associated with a repetitive primary structure based mainly on blocks of eight residues. Similar spectral changes occurred when the protein was heated from 6 to 86 degrees C in aq. 70% (v/v) ethanol or dissolved in increasing concentrations (50-100%, v/v) of trifluoroethanol in water. The studies indicated that the conformation is stabilized by strong hydrophobic interactions and by extensive hydrogen-bonding.     

重要谷类种子贮藏蛋白的特性及改良研究

在成熟谷类种子中,总蛋白约为种子干重的7％～16％,其中大部分为贮藏蛋白。这些贮藏蛋白对于人类和牲畜所需要的营养质量以及在食品加工中都有重要的影响。本文对一些重要谷类种子贮藏蛋白的组成特性以及利用基因工程技术提高谷类种子蛋白质含量和质量进行了全面综述。此外,还简要介绍了在利用基因工程改良谷物种子品质中可能产生的食品安全性问题、如何增加外源基因的表达量和全面提高谷类种子蛋白质含量以及解决的办法。     

The effect of sodium fluoride on cereal seed germination and seedling growth

Abstract. Fluoride has been shown to inhibit germination and seedling establishment in barley cv. Natasha, wheat cv. Axona and rice cv. Ishikari. The concentrations of fluoride were selected so as to give a satisfactory dose-response relationship and also to relate to levels of fluoride present under natural conditions. Concentrations used were zero, 0.5, 1.0, 10 and 40 mol m⁻³ sodium fluoride. In germination studies, barley was found to be least tolerant and rice most tolerant of fluoride. The inhibition was found to be a response to fluoride itself and the observed effects were not due to pH, sodium or an unspecific effect of halide ion. Phosphate, applied at two concentration levels, was unable to overcome the inhibition. Fluoride was also shown to inhibit seedling growth. The inhibitory effects of fluoride may be accounted for by a wide range of metabolic effects including inhibition of gibberellic acid–triggered alpha amylase activity during germination, and later on to inhibition of chlorophyll synthesis in the developing leaves.     

Tetrazolium salt as a seed germination indicator

A preliminary assessment of 2:3:5-triphenyl tetrazolium chloride as a seed germination indicator has been made by testing wheat, barley, oats, peas and vetches. Results as reliable as actual germination tests have been obtained, and the optimum conditions for testing have been determined. The application of this technique to other seeds is also discussed.     

Parasites from feral pigeons as a health hazard for humans

Feral pigeons live in almost every large city in the world. The feeding of pigeons by humans, deliberately or accidentally, allows the build‐up of large populations that can cause a variety of problems, primarily the fouling of buildings and monuments by their droppings. Excreta of wild birds are a well‐known source of pathogenic microorganisms that can cause infection in man. The most important ectoparasites of feral pigeons are the red blood mite, Dermanyssus gallinae, and the pigeon tick, Argas reflexus, both of which can migrate into human living space when they lose their natural hosts. The bites of the red blood mite are irritating but harmless, whereas the pigeon tick can cause severe health problems to predisposed persons. After repeated bites from A. reflexus, people can develop IgE‐mediated (type I) allergy, which in extreme situations may lead to life‐threatening symptoms of anaphylactic shock. So far, one fatality due to A. reflexus deriving from feral pigeons has been reported. In the case of parasitic infestations of humans, the source must be removed by excluding pigeons from further breeding and by disinfection of the environment of pigeon‐breeding sites.     

Differences between cereal crop cultivars in root-associated nitrogen fixation,possible causes of variable yield response to seed inoculation

Large differences in N₂-ase activity with fractions of active plants from 3–67% and maximal activities from 3–35 nmol C₂H₄.h^-1 were found between sterile, Azospirillum-inoculated seedlings of 14 German cereal cultivars. Examples of similar cultivar differences in gnotobiotic or unsterile cereals in response to Azospirillum inoculation, in root exudation and the specificity of bacteria-root interactions are reviewed. As possible causes of yield responses to bacterial seed inoculation N₂-fixation, plant growth regulating metabolites and bacterial interaction with root pathogens are discussed. The need for suitable screening methods to select and breed cultivars with desirable responses to beneficial rhizosphere bacteria is pointed out.     

A cereal haemoglobin gene is expressed in seed and root tissues under anaerobic conditions

Legumes, and a very few non-legume plant species, are known to possess functioning haemoglobin genes. We describe here the characterization of a haemoglobin cDNA isolated from barley. The deduced amino acid sequence shows 71% amino acid identity with a non-legume haemoglobin gene, a further 16% of the residues being conservative replacements. The barley cDNA also hybridizes to genomic sequences in rye, maize and wheat. The demonstration of a gene from a monocotyledon with close sequence homology to the known non-legume plant haemoglobins fills a major gap in the known distribution of haemoglobin genes in the plant kingdom. The expression of the gene is induced in isolated barley aleurone layers exposed to anaerobic conditions, and the roots of flooding-stressed barley plants. The expression of the RNA under anoxic conditions is similar to that of a known anaerobic response gene, alcohol dehydrogenase. Our results suggest that the increased expression of haemoglobin RNA is an integral part of the normal anaerobic response in barley. The findings are discussed in the light of current theories of haemoglobin function and evolution.