<Emphasis Type="Italic">Xerophyta viscosa</Emphasis> Aldose Reductase,XvAld1, Enhances Drought Tolerance in Transgenic Sweetpotato

Sweetpotato is a significant crop which is widely cultivated particularly in the developing countries with high and stable yield. However, drought stress is a major limiting factor that antagonistically influences the crop’s productivity. Dehydration stress caused by drought causes aggregation of reactive oxygen species (ROS) in plants, and aldose reductases are first-line safeguards against ROS caused by oxidative stress. In the present study, we generated transgenic sweetpotato plants expressing aldose reductase, XvAld1 isolated from Xerophyta viscosa under the control of a stress-inducible promoter via Agrobacterium-mediated transformation. Our results demonstrated that the transgenic sweetpotato lines displayed significant enhanced tolerance to simulated drought stress and enhanced recuperation after rehydration contrasted with wild-type plants. In addition, the transgenic plants exhibited improved photosynthetic efficiency, higher water content and more proline accumulation under dehydration stress conditions compared with wild-type plants. These results demonstrate that exploiting the XvAld1 gene is not only a compelling and attainable way to improve sweetpotato tolerance to drought stresses without causing any phenotypic imperfections but also a promising gene candidate for more extensive crop improvement.     

The perceptual and chemical bases of egg discrimination in communally nesting greater anis Crotophaga major

The eggshells of communally breeding greater anis Crotophaga major consist of a blue‐green pigmented calcite matrix overlaid by a chalky white layer of vaterite, both of which are polymorphs of calcium carbonate. The white vaterite layer is intact in freshly laid eggs and may function in protecting the eggs from mechanical damage, but it also abrades during incubation to reveal the blue calcite shell underneath. Previous research has shown that this color change serves a visual signaling function: nesting greater anis can discriminate between eggs that are freshly laid and those that have already been incubated, which allows them to reject asynchronous eggs laid by extra‐group parasites. Here we use avian visual modeling and pigment extraction to assess the perceptual and chemical bases of such egg recognition. We found that there was no overlap between the avian perceptual space occupied by ani eggshells with and without vaterite, and that vaterite lacked both of the pigments found in the eggshell's calcite matrix, bililverdin and protoporphyrin. The visual contrast between the unpigmented vaterite and the blue‐pigmented calcite appears to pre‐date the evolution of the signaling function, since the related guira cuckoo Guira guira, also a communal breeder, lays similarly structured and pigmented eggs but does not use the visual contrast as a signal to detect parasitism.     

SALIVARY ANDROGEN-BINDING PROTEIN (ABP) MEDIATES SEXUAL ISOLATION IN MUS MUSCULUS

We wanted to determine whether the microevolution of the mouse salivary androgen-binding protein (ABP) Alpha subunit gene (Abpa) could mediate sexual selection and thereby have a potential role in maintaining gene pool integrity where radiating mouse subspecies make secondary contact. This hypothesis is based upon previous work in this laboratory, which has shown that each subspecies apparently has its own allele and that these alleles have a 25-fold excess of nonsynonymous/synonymous base substitutions compared to an average protein under purifying selection. We provide direct evidence for ABP-assortative mate selection in a laboratory setting: Mus musculus domesticus and M. m. musculus female mice recognize and discriminate between the territories of male mice that essentially differ solely in their Abpa genotype and, when the males are present, the female prefers to mate with the one of her own ABP type. The observation that females could differentiate between the territories of the two males when those mice were absent suggests that the males marked their territories with ABP. In this study, we also detected ABP on the pelts of male mice and in their environment. It is likely that the animals apply the protein to their pelts by licking and that it is then deposited in their surroundings. We suggest that females of the two subspecies are able to discriminate between males of those subspecies on the basis of this protein molecule. Mouse salivary ABP might present a worthwhile system with which to study a prezygotic isolation mechanism in a mammal.     

Sub-Cellular Element Analysis of a Cyanobacterium (Nostoc sp.) in Symbiosis with Gunnera manicata by ESI and EELS

Element analysis using electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS) was performed in a symbiotic Nostoc sp. strain found in the upper stem tissue of Gunnera manicata, and in Nostoc PCC 9229, a free-living heterocyst-forming cyanobacterium able to enter into symbiosis with the angiosperm Gunnera in reconstitution experiments. ESI and EELS unequivocally identified the four elements nitrogen (N), sulphur (S), phosphorus (P) and oxygen (O) in different inclusion bodies of these biological specimens. High amounts of nitrogen were solely detected in huge cyanophycin granules in vegetative cells of the symbiotic Nostoc strain, whereas large polyphosphate bodies, containing high amounts of phosphorus, sulphur and oxygen, could be seen in the free-living Nostoc PCC 9229. The latter were usually not present or, when found, very small in vegetative cells of the cyanobiont.     

Produce Isolates of the Escherichia coli Ont:H52 Serotype That Carry both Shiga Toxin 1 and Stable Toxin Genes

Produce isolates of the Escherichia coli Ont:H52 serotype carried Shiga toxin 1 and stable toxin genes but only expressed Stx1. These strains had pulsed-field gel electrophoresis profiles that were 90% homologous to clinical Ont:H52 strains that had identical phenotypes and genotypes. All Ont:H52 strains had identical single nucleotide polymorphism profiles that are suggestive of a unique clonal group.