Water stress resilient cereal crops: Lessons from wild relatives

Cereal crops are significant contributors to global diets. As climate change disrupts weather patterns and wreaks havoc on crops, the need for generating stress-resilient, high-yielding varieties is more urgent than ever. One extremely promising avenue in this regard is to exploit the tremendous genetic diversity expressed by the wild ancestors of current day crop species. These crop wild relatives thrive in a range of environments and accordingly often harbor an array of traits that allow them to do so. The identification and introgression of these traits into our staple cereal crops can lessen yield losses in stressful environments. In the last decades, a surge in extreme drought and flooding events have severely impacted cereal crop production. Climate models predict a persistence of this trend, thus reinforcing the need for research on water stress resilience. Here we review: (i) how water stress (drought and flooding) impacts crop performance; and (ii) how identification of tolerance traits and mechanisms from wild relatives of the main cereal crops, that is, rice, maize, wheat, and barley, can lead to improved survival and sustained yields in these crops under water stress conditions.     

The relationship between relative weight and school attendance among elementary schoolchildren

Objective: To determine the relationship between relative weight and school attendance among elementary schoolchildren. Research Methods and Procedures: A total of 1069 fourth to sixth graders from nine elementary schools in the inner city of Philadelphia, PA, were part of an ongoing randomized control trial to assess prevention strategies for obesity. The mean rate of students eligible for free/reduced meals was 82.9 ± 11.5%. Weight was measured in the second semester of the academic year. Absentee data for the entire academic year were recorded by homeroom teachers. Participants were classified into relative weight categories described by the Institute of Medicine: underweight, normal‐weight, overweight, and obese. Results: ANOVA showed that overweight children were absent significantly more than normal‐weight children (12.2 ± 11.7 days vs.10.1 ± 10.5 days) (p < 0.05). Linear regression showed that the obese category remained a significant contributor to the number of days absent even after adjusting for age, race/ethnicity, and gender. Discussion: These data suggest that in addition to the medical and psychosocial consequences of being overweight, heavier children have greater risk for school absenteeism than their normal‐weight peers. As the rate of childhood obesity increases, parallel increases in school absenteeism should be expected.     

4-hydroxynonenal in foodstuffs: heme concentration, fatty acid composition and freeze-drying are determining factors

4-Hydroxynonenal (HNE) is a product of lipid peroxidation. It has been often used as a biomarker of endogenous lipid peroxidation and its concentration is increased in several diseases. But HNE is not only formed during lipid peroxidation occurring in the body. Some authors have shown that it is also present in oxidized oils and in meats. The aim of this study is to compare the effect of food composition (heme iron, fatty acid composition) or freeze-drying on HNE formation in foodstuffs. The methodology is based on extraction/purification procedure followed by HPLC separation with UV detection. As HNE is chemically very reactive and binds easily to proteins, we used radiolabeled HNE to calculate extraction efficiency, so total HNE can be estimated as only free HNE can be measured. The concomitant presence of both heme iron and omega 6 fatty acids, such as linoleic acid, is important for HNE formation in foodstuffs. Freeze-drying increases this formation.     

Yif1B Is Involved in the Anterograde Traffic Pathway and the Golgi Architecture

Yif1B is an intracellular membrane‐bound protein belonging to the Yip family, shown previously to control serotonin 5‐HT_1A receptor targeting to dendrites. Because some Yip proteins are involved in the intracellular traffic between the ER and the Golgi, here we investigated the precise localization of Yif1B in HeLa cells. We found that Yif1B is not resident into the Golgi, but rather belongs to the IC compartment. After analyzing the role of Yif1B in protein transport, we showed that the traffic of the VSVG protein marker was accelerated in Yif1B depleted HeLa cells, as well as in hippocampal neurons from Yif1B KO mice. Conversely, Yif1B depletion in HeLa cells did not change the retrograde traffic of ShTx. Interestingly, in long term depletion of Yif1B as in Yif1B KO mice, we observed a disorganized Golgi architecture in CA1 pyramidal hippocampal neurons, which was confirmed by electron microscopy. However, because short term depletion of Yif1B did not change Golgi structure, it is likely that the implication of Yif1B in anterograde traffic does not rely on its role in structural organization of the Golgi apparatus, but rather on its shuttling between the ER, the IC and the Golgi compartments.      

Dissecting Arabidopsis Gβ signal transduction on the protein surface

The heterotrimeric G-protein complex provides signal amplification and target specificity. The Arabidopsis (Arabidopsis thaliana) Gβ-subunit of this complex (AGB1) interacts with and modulates the activity of target cytoplasmic proteins. This specificity resides in the structure of the interface between AGB1 and its targets. Important surface residues of AGB1, which were deduced from a comparative evolutionary approach, were mutated to dissect AGB1-dependent physiological functions. Analysis of the capacity of these mutants to complement well-established phenotypes of Gβ-null mutants revealed AGB1 residues critical for specific AGB1-mediated biological processes, including growth architecture, pathogen resistance, stomata-mediated leaf-air gas exchange, and possibly photosynthesis. These findings provide promising new avenues to direct the finely tuned engineering of crop yield and traits.     

Separate pathways for O acetylation of polymeric and monomeric sialic acids and identification of sialyl O-acetyl esterase in Escherichia coli K1

O acetylation at carbon positions 7 or 9 of the sialic acid residues in the polysialic acid capsule of Escherichia coli K1 is catalyzed by a phase-variable contingency locus, neuO, carried by the K1-specific prophage, CUS-3. Here we describe a novel method for analyzing polymeric sialic acid O acetylation that involves the release of surface sialic acids by endo-N-acetylneuraminidase digestion, followed by fluorescent labeling and detection of quinoxalinone derivatives by chromatography. The results indicated that NeuO is responsible for the majority of capsule modification that takes place in vivo. However, a minor neuO-independent O acetylation pathway was detected that is dependent on the bifunctional polypeptide encoded by neuD. This pathway involves O acetylation of monomeric sialic acid and is regulated by another bifunctional enzyme, NeuA, which includes N-terminal synthetase and C-terminal sialyl O-esterase domains. A homologue of the NeuA C-terminal domain (Pm1710) in Pasteurella multocida was also shown to be an esterase, suggesting that it functions in the catabolism of acetylated environmental sialic acids. Our combined results indicate a previously unexpected complexity in the synthesis and catabolism of microbial sialic and polysialic acids. These findings are key to understanding the biological functions of modified sialic acids in E. coli K1 and other species and may provide new targets for drug or vaccine development.     

Methods to control ectomycorrhizal colonization: effectiveness of chemical and physical barriers

We conducted greenhouse experiments using Douglas-fir (Pseudotsuga menziesii var. glauca) seedlings where chemical methods (fungicides) were used to prevent ectomycorrhizal colonization of single seedlings or physical methods (mesh barriers) were used to prevent formation of mycorrhizal connections between neighboring seedlings. These methods were chosen for their ease of application in the field. We applied the fungicides, Topas (nonspecific) and Senator (ascomycete specific), separately and in combination at different concentrations and application frequencies to seedlings grown in unsterilized forest soils. Additionally, we assessed the ability of hyphae to penetrate mesh barriers of various pore sizes (0.2, 1, 20, and 500 microm) to form mycorrhizas on roots of neighboring seedlings. Ectomycorrhizal colonization was reduced by approximately 55% with the application of Topas at 0.5 g l(-1). Meshes with pore sizes of 0.2 and 1 microm were effective in preventing the formation of mycorrhizas via hyphal growth across the mesh barriers. Hence, meshes in this range of pore sizes could also be used to prevent the formation of common mycorrhizal networks in the field. Depending on the ecological question of interest, Topas or the employment of mesh with pore sizes <1 microm are suitable for restricting mycorrhization in the field.     

Neurological and physiological disorders in Artemia harboring manipulative cestodes

There are many impressive examples of host manipulation by parasites, but mechanisms underlying these ethological changes, as well as their physiological consequences, are not well characterized. Here, we analyzed part of the cerebral proteome of brine shrimp Artemia infected by manipulative cestodes, using for the first time the ProteinChip Surface-Enhanced Laser Desorption Ionization and Time of Fly Mass Spectrometry (SELDI-TOF MS) system, which has been proposed as an excellent way to analyze the host genome during the host-parasite interaction processes. We found 2 peptides downregulated in individuals infected by the dilepidid, Anomotaenia tringae (4.5 kDa), and by the 2 hymenolepidids, Flamingolepis liguloides and Confluaria podicipina (3.9 kDa), which are potential candidates for involvement with the manipulation process. The identification of 2 head peptides (4.1 and 4.2 kDa) overexpressed in all the categories in brine shrimp living at the surface (both infected individuals and uninfected controls) suggests its association with the different environmental conditions experienced at the water surface. In parallel, brine shrimp infected by C. podicipina showed significant values of triglycerides, potentially augmenting their profitability and attractiveness for the predaceous definitive host (grebes). We discuss our findings in relationship with current ideas on the complexity of parasitically modified organisms.