LEVERAGING FROM GENOTYPE BY ENVIRONMENT INTERACTION FOR BREAD WHEAT PRODUCTION in EASTERN AFRICA

Developing high yielding and stable genotypes for wide and specific adaptation is important in wheat ( Triticum aestivum L.) production. The objective of this study was to exploit the gains from genotype by environment interaction for increased bread wheat production in eastern Africa. Thirty-three advanced bread wheat lines, along with two check varieties (Danda\u2019a and Hidasse) were evaluated at ten locations in Ethiopia and Kenya. The experiment was laid out in alpha lattice design in three replications. The analysis of variance for AMMI model of grain yield showed that environment, genotypes and genotype by environment interaction (GEI) effects were highly significant (P<0.01), and accounted for 62.4, 4.8 and 15.8% of the total sum of squares variations, respectively. High environmental and significant GEI indicated that the environment had major influence for inconsistent performance. Grain yield of the genotypes ranged from 1.58 t ha-1 (G30) to 9.05 t ha-1 (G31). Genotypes G31, G18 and G35 were the best performing lines across environments. The AMMI biplot, using the first two principal components, showed that testing sites Njoro and Arsi-Robe highly discriminated the tested genotypes. Njoro was negatively interacting with high yielding genotypes, and was a different environment from any of the testing locations of Ethiopia for these sets of genotypes. It may be difficult to develop high yielding and stable varieties for the two countries, but one should look for specific adaptation. Genotypes G31 and G18 produced high grain yield, with low stability across locations which were favouring high yielding environments. However, G21 and G8 had above mean grain yield and good stability across locations. Therefore, wheat breeding for specific adaptability is very important to exploit the genetic advantage of specific genotypic performances across the region. However, extensive testing considering many locations across East African countries is vital for delineating and exploiting wheat environments for marked developments.Le d\ue9veloppement de vari\ue9t\ue9s stables et a rendements \ue9lev\ue9s dans le but d\u2019adoption a grande \ue9chelle, est important dans la production du bl\ue9 tendre ( Triticum aestivum L.). L\u2019objectif de cette \ue9tude est d\u2019exploiter l\u2019effet de l\u2019interaction entre g\ue9notypes et environnements (IGE) pour accroitre la production du bl\ue9 tendre en Afrique de l\u2019Est. Trente-trois lign\ue9es avanc\ue9es de bl\ue9 tendre ensemble avec deux vari\ue9t\ue9s de r\ue9f\ue9rence (Danda\u2019a and Hidasse) ont \ue9t\ue9 \ue9valu\ue9es dans dix locations. Le plan exp\ue9rimental \ue9tait en treillis alpha avec trois r\ue9p\ue9titions. La m\ue9thode de l\u2019interaction des effets additifs and multiplicative (AMMI) avait \ue9t\ue9 utilis\ue9e pour le rendement en grain. L\u2019analyse des variances selon ce mod\ue8le a montr\ue9 que l\u2019environnement, le g\ue9notype et l\u2019interaction des deux ont des effets significatifs sur le rendement en grains (P<0,01), et contribuent respectivement, 62,4\ua0; 4,8 et 15,8% \ue0 la variation totale. Un effet important de l\u2019environnement et une interaction significative indiquent que l\u2019environnement a un r\uf4le majeur dans les diff\ue9rences de rendements. Les rendements en grains des g\ue9notypes testes varient de 1.58 t ha-1 (G30) a 9.05 t ha-1 (G31). Les g\ue9notypes G31, G18 et G35 \ue9taient de fa\ue7on g\ue9n\ue9rale, les plus performants. Le biplot g\ue9n\ue8re par AMMI a montr\ue9 que les sites Njoro and Arsi-Robe discriminent nettement les g\ue9notypes test\ue9s. Njoro \ue9tait n\ue9gativement corr\ue9l\ue9 avec les g\ue9notypes a rendement \ue9lev\ue9 et constituait un environnement diff\ue9rent de toutes les autres locations de l\u2019Ethiopie ou ces g\ue9notypes ont \ue9t\ue9 testes. Il peut s\u2019av\ue9rer difficile de d\ue9velopper des vari\ue9t\ue9s \ue0 haut rendement et stable dans les deux pays, mais l\u2019on doit rechercher des vari\ue9t\ue9s adapt\ue9es \ue0 chaque milieu. Les g\ue9notypes G31 et G18 ont eu des rendements \ue9lev\ue9s mais n\u2019ont pas \ue9t\ue9 stables dans les milieux qui se sont av\ue9r\ue9s \ue0 haut rendement. N\ue9anmoins, G21 et G8 ont eu des rendements plus \ue9lev\ue9s que la moyenne et se sont montres stables d\u2019un milieu \ue0 un autre. Il s\u2019ensuit donc que le d\ue9veloppement de vari\ue9t\ue9 de bl\ue9 tendre adapt\ue9 \ue0 chaque milieu serait une bonne approche pour une exploitation efficiente des avantages g\ue9n\ue9tiques des g\ue9notypes \ue0 haute performance. N\ue9anmoins, il est important de faire des essais extensifs prenant en compte plusieurs localit\ue9s des pays de l\u2019Afrique de l\u2019Est afin d\u2019explorer et identifier les milieux propices au bl\ue9 tendre

DEVELOPMENT OF WHEAT GERMPLASM FOR STEM RUST RESISTANCE IN EASTERN AFRICA

Wheat ( Triticum aestivum ) rust outbreak is the primary production constraint in Eastern Africa. Ethiopia, Kenya and Uganda are hot spots for the epidemic of rusts, due to higher rates of evolution of new pathogen races, especially of the virulent stem rust (Puccinia graminis) race, Ug99. The objective of this study was to identify sources of resistance to the major pathotypes of stem rust prevalent in some countries of Eastern Africa. Three hundred and six elite breeding lines, selected and advanced at the Wheat Regional Centre of Excellence (WRCoE) in Ethiopia, were planted in stem rust hot spot areas of the country (Arsi-Robe) and Kenya (Njoro) under natural infections. Stem rust scores of 18, 25.8 and 56.2% of lines at Arsi-Robe; and 35, 49 and 16.7% of lines at Njoro were resistant to moderately resistant, intermediate and moderately susceptible to susceptible category, respectively. Overall coefficient of infection (ACI) at Arsi-Robe (24) was greater than that of Njoro (13), indicating higher disease pressure in Ethiopia than Kenya. Among the lines, 67% at Njoro and 49% at Arsi Robe showed good levels of resistance, with a severity less than 20%. However, only 32% of the lines showed a good level of resistance (<20% severity) in both locations. These lines could have combined resistance to the multiple stem rust races prevailing at both locations. Generally, most of the lines, which showed better resistance at Njoro were susceptible at Arsi-Robe.La rouille de la tige chez le bl\ue9 ( Triticum aestivum ) est l\u2019un des plus importants probl\ue8mes rencontres dans la production du bl\ue9 en Afrique de l\u2019Est. L\u2019Ethiopie, le Kenya et l\u2019Ouganda sont des pays \ue0 fort taux d\u2019\ue9pid\ue9mie de rouille de la tige. Ceci \ue0 cause du taux \ue9lev\ue9 de d\u2019agents pathog\ue8nes, ainsi que l\u2019apparition de nouveaux pathog\ue8nes, dont le plus redoutable (Puccinia graminis) race Ug99. L\u2019objectif de cette \ue9tude \ue9tait d\u2019identifier des sources de r\ue9sistance aux pathotypes majeurs de la rouille de tige qui sevit dans certains pays de l\u2019Afrique de l\u2019Est. Trois cent six lign\ue9es \ue9lites, s\ue9lectionn\ue9es au centre r\ue9gionale d\u2019excellence du bl\ue9 (WRCoE) en Ethiopie, ont \ue9t\ue9 plant\ue9es dans des zones a fort taux de pr\ue9valence de la rouille de tige en Ethiopie (Arsi-Robe) au Kenya (Njoro). Respectivement, 18, 25.8 et 56.2% des lign\ue9es a Arsi-Robe; et 35, 49 et 16.7% des lign\ue9es a Njoro se sont r\ue9v\ue9l\ue9es r\ue9sistantes ou mod\ue9r\ue9ment r\ue9sistantes, interm\ue9diaires, mod\ue9r\ue9ment susceptibles a susceptibles. En somme, le coefficient d\u2019infection (ACI) \ue0 Arsi-Robe (24) \ue9tait plus \ue9lev\ue9 qu\u2019\ue0 Njoro (13), ceci indique que la pression de la rouille de tige est plus \ue9lev\ue9e en Ethiopie qu\u2019au Kenya. Parmi les lign\ue9es \ue9valu\ue9es, 67% \ue0 Njoro et 49% a Arsi Robe sont exhibe des bons niveaux de r\ue9sistance, avec 20% de s\ue9v\ue9rit\ue9. N\ue9anmoins, seul 32% des lign\ue9es ont exhibe une bonne r\ue9sistance (<20% s\ue9v\ue9rit\ue9) dans les deux localit\ue9s. Ces lign\ue9es porteraient surement des g\ue8nes de r\ue9sistance multiple contre les diff\ue9rentes races de champignon pr\ue9sents dans les deux localit\ue9s. G\ue9n\ue9ralement, la plupart des lign\ue9es ayant exhibe une bonne r\ue9sistance a Njoro \ue9taient susceptible a Arsi-Robe

Improved catalytic activity of ruthenium–arene complexes in the reduction of NAD+

A series of neutral Ru-II half-sandwich complexes of the type [(eta(6)-arene)Ru(N,N')Cl] where the arene is para-cymene (p-cym), hexamethylbenzene (hmb), biphenyl (bip), or benzene (bn) and N,N' is N-(2-aminoethyl) -4-(trifluoromethyl)benzenesulfonamide (TfEn), N-(2-aminoethyl)-4-toluenesulfonamide (TsEn), or N-(2-aminoethyl)-methylenesulfonamide (MsEn) were synthesized and characterized. X-ray crystal structures of [(p-cym)Ru(MsEn)Cl] (1), [(hmb)Ru(TsEn)Cl] (5), [(hmb)Ru(TfEn)Cl] (6), [(bip)Ru(MsEn)Cl] (7), and [(bip)Ru(TsEn)Cl] (8) have been determined. The complexes can regioselectively catalyze the transfer hydrogenation of NAD(+) to give 1,4-NADH in the presence of formate. The turnover frequencies (TOF) when the arene is varied decrease in the order bn > bip > p-cym > hmb for complexes with the same N,N' chelating ligand. The TOF decreased with variation in the N,N' chelating ligand in the order TfEn > TsEn > MsEn for a given arene. [(bn)Ru(TfEn)Cl] (12) was the most active, with a TOP of 10.4 h(-1). The effects of NAD(+) and formate concentration on the reaction rates were determined for [(p-cym)Ru(TsEn)Cl] (2). Isotope studies implicated the formation of [(arene)Ru(N,N')(H)] as the rate-limiting step. The coordination of formate and subsequent CO2 elimination to generate the hydride were modeled computationally by density functional theory (DFT). CO2 elimination occurs via a two-step process with the coordinated formate first twisting to present its hydrogen toward the metal center. The computed barriers for CO2 release for arene = benzene follow the order MsEn > TsEn > TfEn, and for the Ms En system the barrier followed bn < hmb, both consistent with the observed rates. The effect of methanol on transfer hydrogenation rates in aqueous solution was investigated. A study of pH dependence of the reaction in D2O gave the optimum pH* as 7.2 with a TOF of 1.58 h(-1) for 2. The series of compounds reported here show an improvement in the catalytic activity by an order of magnitude compared to the ethylenediamine analogues

Protein tyrosine phosphatase 1B inhibitors isolated from Artemisia roxburghiana

Artemisia roxburghiana is used in traditional medicine for treating various diseases including diabetes. The present study was designed to evaluate the antidiabetic potential of active constituents by using protein tyrosine phosphatase 1B (PTP1B) as a validated target for management of diabetes. Various compounds were isolated as active principles from the crude methanolic extract of aerial parts of A. roxburghiana. All compounds were screened for PTP1B inhibitory activity. Molecular docking simulations were performed to investigate the mechanism behind PTP1B inhibition of the isolated compound and positive control, ursolic acid. Betulinic acid, betulin and taraxeryl acetate were the active PTP1B principles with IC50 values 3.49 ± 0.02, 4.17 ± 0.03 and 87.52 ± 0.03 µM, respectively. Molecular docking studies showed significant molecular interactions of the triterpene inhibitors with Gly220, Cys215, Gly218 and Asp48 inside the active site of PTP1B. The antidiabetic activity of A. roxburghiana could be attributed due to PTP1B inhibition by its triterpene constituents, betulin, betulinic acid and taraxeryl acetate. Computational insights of this study revealed that the C-3 and C-17 positions of the compounds needs extensive optimization for the development of new lead compounds

Contrasting anticancer activity of half-sandwich iridium(III) complexes bearing functionally diverse 2-phenylpyridine ligands

We report the synthesis, characterization, and antiproliferative activity of 15 iridium(III) half-sandwich complexes of the type [(η5-Cp*)Ir(2-(R′-phenyl)-R-pyridine)Cl] bearing either an electron-donating (−OH, −CH2OH, −CH3) or electron-withdrawing (−F, −CHO, −NO2) group at various positions on the 2-phenylpyridine (2-PhPy) chelating ligand giving rise to six sets of structural isomers. The X-ray crystal structures of [(η5-Cp*)Ir(2-(2′-fluorophenyl)pyridine)Cl] (1) and [(η5-Cp*)Ir(2-(4′-fluorophenyl)pyridine)Cl] (2) exhibit the expected “piano-stool” configuration. DFT calculations showed that substituents caused only localized effects on the electrostatic potential surface of the chelating 2-PhPy ligand of the complexes. Hydrolysis of all complexes is rapid, but readily reversed by addition of NaCl. The complexes show preferential binding to 9-ethylguanine over 9-methyladenine and are active catalysts for the oxidation of NADH to NAD+. Antiproliferative activity experiments in A2780 ovarian, MCF-7 breast, A549 lung, and HCT116 colon cancer cell lines showed IC50 values ranging from 1 to 89 μM, with the most potent complex, [(η5-Cp*)Ir(2-(2′-methylphenyl)pyridine)Cl] (13) (A2780 IC50 = 1.18 μM), being 10× more active than the parent, [(η5-Cp*)Ir(2-phenylpyridine)Cl], and 2× more active than [(η5-CpxPh)Ir(2-phenylpyridine)Cl]. Intriguingly, contrasting biological activities are observed between structural isomers despite exhibiting similar chemical reactivity. For pairs of structural isomers both the nature and position of the functional group can affect the hydrophobicity of the complex. An increase in hydrophobicity resulted in enhanced cellular-iridium accumulation in A2780 ovarian cells, which generally gave rise to an increase in potency. The structural isomers [(η5-Cp*)Ir(2-(4′-fluorophenyl)pyridine)Cl] (2) and [(η5-Cp*)Ir(2-phenyl-5-fluoropyridine)Cl] (4) preferentially localized in the cytosol > membrane and particulate > nucleus > cytoskeleton. This work highlights the strong dependence of biological behavior on the nature and position of the substituent on the chelating ligand and shows how this class of organometallic anticancer complexes can be fine-tuned to increase their potency without using extended cyclopentadienyl systems

Hypoxia Sensitive Metal β-Ketoiminate Complexes Showing Induced Single Strand DNA Breaks and Cancer Cell Death by Apoptosis

A series of ruthenium and iridium complexes have been synthesised and characterised with 20 novel crystal structures discussed. The library of β-ketoiminate complexes has been shown to be active against MCF-7 (human breast carcino-ma), HT-29 (human colon carcinoma), A2780 (human ovarian carcinoma) and A2780cis (cisplatin resistant human ovarian carcinoma) cell lines, with selected complexes being more than three times as active as cisplatin against the A2780cis cell line. Complexes have also been shown to be highly active under hypoxic conditions, with the activities of some complexes increasing with a decrease in O2 concentration. The enzyme thioredoxin reductase is over-expressed in cancer cells and complexes reported herein have the advantage of inhibiting this enzyme, with IC50 values measured in the nanomolar range. The anti-cancer activity of these complexes was further investigated to determine whether activity is due to effects on cellular growth or cell survival. The complexes were found to induce significant cancer cell death by apoptosis with levels induced correlating closely with activity in chemosensitivity studies. As a possible cause of cell death, the ability of the complexes to induce damage to cellular DNA was also assessed. The complexes failed to induce double strand DNA break or DNA crosslinking but induced significant levels of single DNA strand breaks indi-cating a different mechanism of action to cisplatin

Withanolides and related steroids

Since the isolation of the first withanolides in the mid-1960s, over 600 new members of this group of compounds have been described, with most from genera of the plant family Solanaceae. The basic structure of withaferin A, a C28 ergostane with a modified side chain forming a δ-lactone between carbons 22 and 26, was considered for many years the basic template for the withanolides. Nowadays, a considerable number of related structures are also considered part of the withanolide class; among them are those containing γ-lactones in the side chain that have come to be at least as common as the δ-lactones. The reduced versions (γ and δ-lactols) are also known. Further structural variations include modified skeletons (including C27 compounds), aromatic rings and additional rings, which may coexist in a single plant species. Seasonal and geographical variations have also been described in the concentration levels and types of withanolides that may occur, especially in the Jaborosa and Salpichroa genera, and biogenetic relationships among those withanolides may be inferred from the structural variations detected. Withania is the parent genus of the withanolides and a special section is devoted to the new structures isolated from species in this genus. Following this, all other new structures are grouped by structural types. Many withanolides have shown a variety of interesting biological activities ranging from antitumor, cytotoxic and potential cancer chemopreventive effects, to feeding deterrence for several insects as well as selective phytotoxicity towards monocotyledoneous and dicotyledoneous species. Trypanocidal, leishmanicidal, antibacterial, and antifungal activities have also been reported. A comprehensive description of the different activities and their significance has been included in this chapter. The final section is devoted to chemotaxonomic implications of withanolide distribution within the Solanaceae. Overall, this chapter covers the advances in the chemistry and biology of withanolides over the last 16 years.Fil: Misico, Rosana Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (i); ArgentinaFil: Nicotra, V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; ArgentinaFil: Oberti, Juan Carlos María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; ArgentinaFil: Barboza, Gloria Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacia; ArgentinaFil: Gil, Roberto Ricardo. University Of Carnegie Mellon; Estados UnidosFil: Burton, Gerardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (i); Argentin