In vitro embryo rescue and plant regeneration following self-pollination with irradiated pollen in cassava (Manihot esculenta Crantz)

Cassava is a highly heterozygous species; hence, current methods used in classical cassava breedingcannot match the urgent need to high yielding varieties. Recently, progress was made through androgenesis and gynogenesis as pathways for raising doubled cassava haploid lines to overcome problems associated with cassava’s inherent reproductive biology, but these efforts were limited (nocandidate cassava plantlets were regenerated). For the first time, this study shows that pollen irradiation coupled with self-pollination and embryo rescue regenerated 62 candidate cassava plantlets. Plants of an elite cassava variety, Nase14, served as a mother plant and as the pollen donor for the irradiation. Irradiation dosages of 50 to 250 Gray studied across five pollination events and 300 or 500 Gray in one pollination event caused a reduction in pollen germination up to 67.0%. By 15 days after pollination (DAP) with irradiated pollen, up to 89.7% of the pollinated flowers had aborted. By embryo rescue time (42 DAP), significant differences were observed in number of fruits, seeds and embryos generated, with the non-irradiated pollen treatments having significantly higher numbers. Sixteen (16) heterozygous SSR markers in the parent and ploidy analysis showed that none of the regenerated plants was haploid or homozygous. However, the plantlets resulting from pollination with non-irradiated pollen had 56.2% homozygous loci, while progeny derived from irradiated treatments had frequencies of homozygous loci between 28.1 and 55.0%. This is the first time to use irradiated pollen in cassava as a pathway to generate candidate plantlets as an initial step in double haploid production.Key words: Cassava, doubled haploids, embryo rescue, plant regeneration, pollen germination, pollenirradiation

Serological and molecular investigation for brucellosis in swine in selected districts of Uganda

Brucellosis is a notifiable zoonotic disease affecting livestock, humans and wildlife in Uganda. Human brucellosis cases are frequently reported and the increasing incidence is suggestive of increasing disease in the livestock population. Pigs are among the livestock species that can be infected with human pathogenic Brucella suis biovars 1 and 3 and can be a significant source of brucellosis for humans. Uganda has a rapidly growing pig population and the pork consumption per capita is the highest in East Africa. The objective of this work was to determine the seroprevalence of brucellosis in Ugandan pigs

Norbornene probes for the study of cysteine oxidation

Abstract not availableLisa J. Alcock, Kyle D. Farrell, Mawey T. Akol, Gregory H. Jones, Matthew M. Tierney, Holger B. Kramer, Tara L. Pukala, Gonçalo J.L. Bernardes, Michael V. Perkins, Justin M. Chalke

Studies of pigeonpea insect pests and their management in Kenya, Malawi, Tanzania and Uganda

Systematic surveys were conducted in farmers= fields in Kenya, Malawi, Tanzania, and Uganda to determine the incidence, distribution and damage levels due to insect pests of pigeonpea seeds. Three surveys were conducted in eastern Kenya, one in 1992 and two in 1995. Two surveys, one per country per year - were conducted in Malawi, Tanzania, and Uganda in 1995 and 1996. Key insect pests were pod sucking bugs (dominated by Clavigralla tomentosicollis Stal), pod and seed boring Lepidoptera (Helicoverpa armigera Hübner, Maruca vitrata (= testulalis) Geyer, Etiella zinkenella Treitschke), and pod fly (Melanagromyza chalcosoma Spencer). Seed damage due to insect pests were 22, 15, 14, and 16% in Kenya, Malawi, Tanzania, and Uganda, respectively. Damage levels indicated that pod sucking bugs were more damaging in Malawi (caused 69% of total seed damage) and Kenya (43%), while pod borers caused more damage in Tanzania (50%) and Uganda (54%). Pod fly caused more damage in Kenya than in the other countries. Pod borer damage was high in early maturing crops and pod fly in late maturing crops, while pod sucking bugs damage was high regardless of crop maturity period. Greater variations in seed damage were observed between locations in Kenya, Malawi, and Tanzania than in Uganda. Warm and dry locations had less seed damage than warm and humid, cool and dry, or cool and humid locations in Kenya, Malawi and Tanzania. None of the farmers visited in Malawi, Tanzania, and Uganda used conventional pesticides on pigeonpea in the field. Over 80% of these farmers used traditional methods in storage pest management. In contrast, 35 and 53% of farmers in Kenya had used conventional pesticides on long-duration pigeonpea genotypes in their fields

Norbornene probes for the study of cysteine oxidation

Cysteine residues on proteins can react with cellular oxidants such as hydrogen peroxide. While this process is important for scavenging excess reactive oxygen species, the products of this oxidation may also mediate cell signalling. To understand the role of cysteine oxidation in biology, selective probes are required to detect and quantify its occurence. Cysteine oxidation products such as sulfenic acids are sometimes unstable and therefore short-lived. If such cysteine derivatives are to be analysed, rapid reaction with the probe is required. Here we introduce norbornene derivatives as probes for cysteine oxidation, and demonstrate their ability to trap sulfenic acids. The synthesis of norbornene derivatives containing alkyne or biotin affinity tags are also reported to facilitate the use of these probes in chemical biology and proteomics

Norbornene probes for the study of cysteine oxidation

© 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license http://creativecommons.org/licenses/by/4.0/).Cysteine residues on proteins can react with cellular oxidants such as hydrogen peroxide. While this process is important for scavenging excess reactive oxygen species, the products of this oxidation may also mediate cell signalling. To understand the role of cysteine oxidation in biology, selective probes are required to detect and quantify its occurrence. Cysteine oxidation products such as sulfenic acids are sometimes unstable and therefore short-lived. If such cysteine derivatives are to be analysed, rapid reaction with the probe is required. Here we introduce norbornene derivatives as probes for cysteine oxidation, and demonstrate their ability to trap sulfenic acids. The synthesis of norbornene derivatives containing alkyne or biotin affinity tags are also reported to facilitate the use of these probes in chemical biology and proteomics

The Normative Agency of Regional Organizations and Non‐governmental Organizations in International Peace Mediation

This article analyzes the increasingly prominent role of regional organizations (ROs) and non‐governmental organizations (NGOs) in promoting norms in mediation processes. In particular, we seek to understand the processes by which RO and NGO mediators promote the inclusivity norm to negotiating parties and the outcomes that result. We employ the concepts of local agency and social practices in examining the normative agency of ROs and NGOs in promoting and redefining the inclusivity norm. Through illustrative case studies of peace processes in South Sudan and Myanmar, we argue that ROs’ and NGOs’ mediation practices reflect their claims to alternative resources of power, such as long‐standing expertise and insider status in the context, and build congruence with strong local norms. We provide nuanced theoretical insights on RO and NGO mediators’ claims to agency and provide empirical illustrations on how these claims contribute to constitutive changes to norms