Genetic diversity in traditional Ethiopian highland maize accessions assessed by AFLP markers and morphological traits

In the highland regions of Ethiopia the heterogeneity of the land, the climate, and soil favors the presence of a large number of landraces. We analyzed a representative sample of 62 traditional Ethiopian highland maize accessions, using amplified fragment length polymorphism (AFLP^®) markers and morphological traits with the aim to group the accessions based on the their genetic profiles and morphological traits, to study agroecological variation and to assess the level of correlation between phenotypic and genetic distances. Eight EcoRI/MseI primer combinations and 15 morphological traits were used. The accessions varied significantly for all of the measured morphological traits. Of a total of 650 AFLP markers that were scored, 89.5% were polymorphic. Pair-wise genetic distance estimates based on AFLP data revealed dissimilarity coefficients ranging from 0.32 to 0.69 (mean of 0.57). Cluster analysis of the AFLP data grouped most accessions collected from the Northern highlands into one major cluster. It, however, failed to separate the Western and Southern accessions into different clusters. Regardless of the large variation in environmental conditions between agroecologies, only 9% of the total genetic variation was found between agroecologies, whereas 91% was found within agroecologies in Ethiopia. This finding may be explained by long distance seed exchange, continuous seed introduction and gene flow between agroecologies. The relationship between morphological and AFLP-based distances was significant and positive. Based on this study, three groups of highland accessions, with distinctive genetic profiles and morphological traits were identified. This information will be useful for further collections and conservation of the unique diversity included in the highland maize landraces of Ethiopia.     

Newly discovered orally active pure antiestrogens

In order to develop orally active pure antiestrogens, we incorporated the carboxy-containing side chains into the 7alpha-position of the steroid scaffold and found that 17-keto derivative CH4893237 (12b) functioned as a pure antiestrogen with its oral activity much superior to clinically used pure antiestrogen, ICI182,780. Results from the pharmacokinetic evaluation indicated that the potent antiestrogen activity at oral dosing in mice attributed to both improved absorption from the intestinal wall and metabolic stability in liver.     

E3 ubiquitin ligase synoviolin is involved in liver fibrogenesis

Background and Aim

Chronic hepatic damage leads to liver fibrosis, which is characterized by the accumulation of collagen-rich extracellular matrix. However, the mechanism by which E3 ubiquitin ligase is involved in collagen synthesis in liver fibrosis is incompletely understood. This study aimed to explore the involvement of the E3 ubiquitin ligase synoviolin (Syno) in liver fibrosis.

Methods

The expression and localization of synoviolin in the liver were analyzed in CCl₄-induced hepatic injury models and human cirrhosis tissues. The degree of liver fibrosis and the number of activated hepatic stellate cells (HSCs) was compared between wild type (wt) and Syno^+/− mice in the chronic hepatic injury model. We compared the ratio of apoptosis in activated HSCs between wt and Syno^+/− mice. We also analyzed the effect of synoviolin on collagen synthesis in the cell line from HSCs (LX-2) using siRNA-synoviolin and a mutant synoviolin in which E3 ligase activity was abolished. Furthermore, we compared collagen synthesis between wt and Syno^−/− mice embryonic fibroblasts (MEF) using quantitative RT-PCR, western blotting, and collagen assay; then, we immunohistochemically analyzed the localization of collagen in Syno^−/− MEF cells.

Results

In the hepatic injury model as well as in cirrhosis, synoviolin was upregulated in the activated HSCs, while Syno^+/− mice developed significantly less liver fibrosis than in wt mice. The number of activated HSCs was decreased in Syno^+/− mice, and some of these cells showed apoptosis. Furthermore, collagen expression in LX-2 cells was upregulated by synoviolin overexpression, while synoviolin knockdown led to reduced collagen expression. Moreover, in Syno^−/− MEF cells, the amounts of intracellular and secreted mature collagen were significantly decreased, and procollagen was abnormally accumulated in the endoplasmic reticulum.

Conclusion

Our findings demonstrate the importance of the E3 ubiquitin ligase synoviolin in liver fibrosis.     

Avian Cone Photoreceptors Tile the Retina as Five Independent,Self-Organizing Mosaics

The avian retina possesses one of the most sophisticated cone photoreceptor systems among vertebrates. Birds have five types of cones including four single cones, which support tetrachromatic color vision and a double cone, which is thought to mediate achromatic motion perception. Despite this richness, very little is known about the spatial organization of avian cones and its adaptive significance. Here we show that the five cone types of the chicken independently tile the retina as highly ordered mosaics with a characteristic spacing between cones of the same type. Measures of topological order indicate that double cones are more highly ordered than single cones, possibly reflecting their posited role in motion detection. Although cones show spacing interactions that are cell type-specific, all cone types use the same density-dependent yardstick to measure intercone distance. We propose a simple developmental model that can account for these observations. We also show that a single parameter, the global regularity index, defines the regularity of all five cone mosaics. Lastly, we demonstrate similar cone distributions in three additional avian species, suggesting that these patterning principles are universal among birds. Since regular photoreceptor spacing is critical for uniform sampling of visual space, the cone mosaics of the avian retina represent an elegant example of the emergence of adaptive global patterning secondary to simple local interactions between individual photoreceptors. Our results indicate that the evolutionary pressures that gave rise to the avian retina''s various adaptations for enhanced color discrimination also acted to fine-tune its spatial sampling of color and luminance.     

Genetic reduction of mTOR extends lifespan in a mouse model of Hutchinson‐Gilford Progeria syndrome

Hutchinson‐Gilford progeria syndrome (HGPS) is a rare accelerated aging disorder most notably characterized by cardiovascular disease and premature death from myocardial infarction or stroke. The majority of cases are caused by a de novo single nucleotide mutation in the LMNA gene that activates a cryptic splice donor site, resulting in production of a toxic form of lamin A with a 50 amino acid internal deletion, termed progerin. We previously reported the generation of a transgenic murine model of progeria carrying a human BAC harboring the common mutation, G608G, which in the single‐copy state develops features of HGPS that are limited to the vascular system. Here, we report the phenotype of mice bred to carry two copies of the BAC, which more completely recapitulate the phenotypic features of HGPS in skin, adipose, skeletal, and vascular tissues. We further show that genetic reduction of the mechanistic target of rapamycin (mTOR) significantly extends lifespan in these mice, providing a rationale for pharmacologic inhibition of the mTOR pathway in the treatment of HGPS.     

Manipulation of light and CO2 environments of the primary leaves of bean (Phaseolus vulgaris L.) affects photosynthesis in both the primary and the first trifoliate leaves: involvement of systemic regulation.

Possible involvement of systemic regulation of the photosynthetic properties of young leaves by the local environments and/or photosynthate production of the mature leaves were examined using Phaseolus vulgaris plants. When primary leaves (PLs) were treated with air containing 150 microL CO2 L(-1) with the other plant parts in ambient air at a photosynthetic photon flux density (PPFD) of 300 micromol photon m(-2) s(-1), decreases in the photosynthetic rate measured at 360 microL CO2 L(-1) and a PPFD of 300 micromol photon m(-2) s(-1) (A360) were markedly retarded in both PLs and the first trifoliate leaves (TLs) as compared to plants treated with 400 microL CO2 L(-1). Conversely, when PLs were treated with 1000 microL CO2 L(-1), decreases in A360 were accelerated in both PLs and TLs. Shading of PLs accelerated the decrease in PL A360, and delayed the decrease in TLs. In the CO2 treatments, changes in A360 in TLs were mainly attributed to the changes in ribulose bisphosphate (RuBP) carboxylation rate, while the shading of PLs caused increases in both the RuBP carboxylation and regeneration rates in TLs. The ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) activity on chlorophyll basis, an indicator of sun/shade acclimation, differed both among PLs and among TLs in accordance with the redox state of photosystem II (PSII) in PLs. Although carbohydrate contents of TLs were not affected by any manipulation of PLs, changes in the photosynthetic capacities of TLs acted to compensate for changes in PL photosynthesis. These results clearly indicate that the CO2 and shade treatments of PLs not only affect photosynthetic properties of the PLs themselves, but also systemically affected the photosynthetic properties of TLs. Possible roles of the redox state and photosynthate concentration in PLs in regulation of photosynthesis in PLs and TLs are discussed.     

Direct protein sequencing of wheat mitochondrial ATP synthase subunit 9 confirms RNA editing in plants

RNA editing, a process that results in the production of RNA molecules having a nucleotide sequence different from that of the initial DNA template, has been demonstrated in several organisms using different biochemical pathways. Very recently RNA editing was described in plant mitochondria following the discovery that the sequence of certain wheat and Oenothera cDNAs is different from the nucleotide sequence of the corresponding genes. The main conversion observed was C to U, leading to amino acid changes in the deduced protein sequence when these modifications occurred in an open reading frame. In this communication we show the first attempt to isolate and sequence a protein encoded by a plant mitochondrial gene. Subunit 9 of the wheat mitochondrial ATP synthase complex was purified to apparent homogeneity and the sequence of the first 32 amino acid residues was determined. We have observed that at position 7 leucine was obtained by protein sequencing, instead of the serine predicted from the previously determined genomic sequence. Also we found phenylalanine at position 28 instead of a leucine residue. Both amino acid conversions, UCA (serine) to UUA (leucine) and CUC (leucine) to UUC (phenylalanine), imply a C to U change. Thus our results seem to confirm, at the protein level, the RNA editing process in plant mitochondria.     

Colonization ability as an indicator of enhanced biocontrol capacity—An example using two Bacillus amyloliquefaciens strains and Botrytis cinerea infection of tomatoes

An understanding of biocontrol activities is important when developing microorganism‐based alternatives to conventional fungicides. From our bacterial collection, we selected two strains (BBC023 and BBC047) for their outstanding antagonistic capacity against fungal phytopathogens and growth‐promoting abilities towards Arabidopsis thaliana. According to physiological and molecular characterizations, both strains were classified as Bacillus amyloliquefaciens and were tested against Botrytis cinerea in vitro and in a tomato. Both strains secrete lipopeptide‐like compounds that contribute to their in vitro antagonism. SEM‐images showed altered B. cinerea mycelial structures that were consistent with previous reports of the direct action of lipopeptides against fungal hyphae. The strains were applied to the roots (R), leaves (foliar ‐ F) or root/leaves (R/F) on tomato plants. All treatments significantly reduced the severity of B. cinerea infection (measured as a control index). However, only root applications (R and R/F) led to growth promotion in the tomato plants. We detected the production of indole acetic acid (IAA) and 2,3‐butanediol as growth promotion traits in the two strains. For both strains, the R/F treatment showed the highest control index, suggesting a synergic effect of direct antagonism against B. cinerea and resistance induction in the plant. In addition, in vitro antagonism of BBC023 and BBC047 against B. cinerea was similar; whereas in the F application, strain BBC047 significantly improved plant resistance and maintained a higher population density over time on tomato leaves, compared to BBC023. BBC047 was also able to produce a complex and robust biofilm in Msgg medium compared with that of BBC023. We linked the reduced biocontrol of BBC023 on leaves with its limited ability to generate robust biofilms and colonize the phylloplane. At last, we highlight the potential of the native Bacillus strains as promising alternatives for the development of bioproducts for sustainable agriculture.     

Immobilization of Saccharomyces cerevisiae for Ethanol Fermentation on γ-Alumina Particles using a Spray-Dryer

Saccharomyces cerevisiae was immobilized on γ-alumina particles with binder polymer by a spray-drying process. Batch fermentations of sucrose to ethanol were performed using the immobilized cells. The optimum pH was 4, and this helped to minimize microbial contamination and facilitate electrostatic attraction between the γ-alumina particles and the yeast cells. Addition of yeast extract resulted in high ethanol conversion. The reasons for differences between cellulose acetate phthalate (CAP) and styrene-maleic acid co-polymer (SMC) as binders on ethanol conversion were not apparent. The release of binder with the SMC from the γ-alumina was less than that from the CAP. Presoaking of γ-alumina particles in resin for binder solution before the immobilization using a spray-dryer was effective in achieving high ethanol conversion.