Using translational research to enhance farmers’ voice: a case study of the potential introduction of GM cassava in Kenya’s coast

Genetically modified (GM) cassava is currently being developed to address problems of diseases that threaten the food security of farmers in developing countries. The technologies are aimed at smallholder farmers, in hopes of reducing the vulnerability of cassava production to these diseases. In this paper we examine barriers to farmers’ voice in the development of GM cassava. We also examine the role of a translational research process to enhance farmers’ voice, to understand the sources of vulnerability farmers in a group in Kenya’s Coast face, and to determine if their concerns are consistent with those of the scientists in agriculture addressing farmers’ needs. A two-way communication participatory process provided insights into the complex vulnerability context of farmers, their primary concerns with processing and markets of cassava in order to improve livelihoods, the lack of networks with two way communication flows, and the lack of information on GM technologies. The translational research engaged farmers and scientists in an iterative process where scientists are learning what farmers need, and farmers are learning about the potential benefits and risks from GM technologies, while at the same time expressing their concerns.     

Stability of RAPD markers for determining cultivar specific DNA profiles in rye (Secale cereale L.)

Summary Cultivar specific DNA profiles in rye were revealed by polymerase chain reaction (PCR) using randomly amplified polymorphic DNA (RAPD) sequences. Ten base primers were used for the amplification of genomic DNA of rye cultivars by PCR. RAPD analysis was found to be reproducible among samples between PCR runs. When amplification profiles of different rye cultivars were compared using various primers, the overall profiles were cultivar specific. However, not all primers revealed polymorphisms. These primers appear to amplify conserved sequences in all rye cultivars. Intracultivar studies were conducted on two of the cultivars. In the cultivar Imperial, no polymorphisms were observed among ten plants analyzed with five primers. In the cultivar Balboa, polymorphisms were observed among fifty plants with four of the ten primers analyzed. Despite the small amount of intracultivar variability, RAPD analysis has the potential to be a rapid and reliable method of cultivar identification in this outcrossing species.     

Aging of whiskey increases the potentiation of GABA(A) receptor response

It is known that the target of most mood-defining compounds such as ethanol is an ionotropic gamma-aminobutyric acid receptor (GABA(A) receptor). The potentiation of the response of these inhibitory neurotransmitter receptors induces anxiolytic, sedative, and anesthetic activities in the human brain. Because both extracts of whiskey by pentane and fragrant components in whiskey potentiate the GABA(A) receptor-mediated response, GABA(A) receptors were expressed in Xenopus oocyte by injecting cRNAs prepared from the cloned cDNA for the alpha(1) and beta(1) subunits of the bovine receptors in order to study the effects of whiskey itself on the GABA(A) receptor-mediated response. Whiskey itself also potentiated the electrical responses of GABA(A) receptors generally more than ethanol at the same concentration as that of the whiskey. The potentiation of the GABA(A) receptor-mediated response increased with the aging period of the whiskey. Inhalation of whiskey to mice increased the sleeping time induced by pentobarbital more than that of the same concentration of ethanol as the whiskey. These results suggest that not only ethanol but also minor components in whiskey play an important role in the potentiation of GABA(A) receptor-mediated response and possibly the sedative effect of whiskey. Although the minor components are present in extremely small quantities compared with ethanol in alcoholic beverages, they may modulate the mood or consciousness of humans through the potentiation of the GABA(A) receptor response after absorption into the brain, because these hydrophobic compounds are easily absorbed into the brain across the blood-brain barrier and are several thousands times as potent as ethanol in the potentiation of the GABA(A) receptor-mediated response.     

Effects of coffee components on the response of GABA(A) receptors expressed in Xenopus oocytes

The effects of both coffee components and coffee extract on the electrical responses of GABA(A) receptors expressed in Xenopus oocytes were studied by injecting cRNAs of the alpha(1) and beta(1) subunits of the bovine receptors. The aqueous extract of coffee dose-dependently inhibited the GABA-elicited responses, whereas the lipophilic extract of coffee by diethyl ether slightly potentiated it at low doses (0.1-0.4 microL/mL) but showed inhibition at high doses (0.5-0.8 microL/mL). Theophylline inhibited the response in a noncompetitive mechanism (K(i) = 0.55 mM), whereas theobromine and trigonelline hydrochloride inhibited it in a competitive manner, K(i) = 3.8 and 13 mM, respectively. Benzothiazole, catechol, 2,4-dimethylstyrene, guaiacol, 1-octen-3-ol, sotolone, and 2,3,5-trimethylphenol potentiated the responses significantly. Potentiation elicited by guaiacol and sotolone was independent of GABA concentrations, whereas that by 1-octen-3-ol was dependent. When 1-octen-3-ol (100 mg/kg) was orally administered to mice prior to intraperitoneal administration of pentobarbital, the sleeping time of mice induced by pentobarbital increased significantly.     

Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates

Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC₉₀ of cinnamaldehyde against different Candida isolates ranged 100–500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H⁺-ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.     

The role of informal contracts in the growth of small cattle herds on the floodplains of the Lower Amazon

In the absence of access to formal credit, informal contracts with independent investors give the small ranchers of the Lower Amazon an acceptable means through which to surmount the high investment hurdle of starting a cattle herd. These contracts – called sociedades – allow small ranchers to raise an outside investor's cattle in return for a portion of the offspring and are commonplace in the cattle production systems of the Amazon. But, notwithstanding a vast literature on cattle production in the Amazon, informal contracts have been largely overlooked. This paper presents the results of a field survey and financial analysis for informal contracts on small ranches in the Lower Amazon. In the results, we suggest that informal contracts are an important means of cattle herd start-up and herd production for small ranchers. Internal rates of returns in cattle production under these contracts are in the range of –7 to –12% for the small rancher and 12% for the investor. The net present value of the contract to the small rancher ranges from –R$1219 to –R$8599 and from R$1681 to R$8845 for the investor, for a 10-year period, depending on herd size. Financial returns contracts are sensitive to the contract design – e.g., to who pays health costs – and to beef prices. The small ranchers have a negative IRR, lose money, and bear all the risk of loss, yet persist in using this form of herd development. We surmise that this is due to the non-financial benefits of cattle ownership and the lack of access to formal credit structures. In conclusion, although outside the formal economy and apparently financially unrewarding, these contracts are an important mechanism by which the small ranchers on the Amazon Floodplains create cattle herds.     

Subcellular compartmentation of sugars in wheat leaves under the influence of salinity and boron toxicity

In this study, long-term effects of salinity and high boron (B) on subcellular distribution of sugars in wheat leaves were investigated. Four treatments with three replications of each; control, high B, sodium chloride (NaCl) and NaCl + high B, respectively were established according to completely randomized design. Plants were grown hydroponically and harvested after 6 weeks onset of experiment. NaCl treatment markedly decreased the shoot fresh and dry weight compared to high B or NaCl + high Boron. It increased the sugar concentrations in subcellular compartments, whereas decreased in NaCl + high B. Contrary, NaCl either alone or in combination with high B decreased the sugar contents in whole leaf compared to control or high B. Overall, higher concentrations of sugars were observed in symplast compared to apoplast indicating the symplast as major compartment for sugar transport. Furthermore, wheat plants accumulate sugars in subcellular compartments to maintain their growth under stress conditions.     

Effect of 3-O-octanoyl-(+)-catechin on the responses of GABA(A) receptors and Na+/glucose cotransporters expressed in xenopus oocytes and on the oocyte membrane potential

Recently, 3-O-octanoyl-(+)-catechin (OC) was synthesized from (+)-catechin (C) by incorporation of an octanoyl chain into C in the light of (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg), which are the major polyphenols found in green tea and have strong physiological activities. OC was found to inhibit the response of ionotropic gamma-aminobutyric acid (GABA) receptors (GABA(A) receptors) and Na+/glucose cotransporters expressed in Xenopus oocytes in a noncompetitive manner more strongly than does C. OC also induced a nonspecific membrane current and decreased the membrane potential of the oocyte, and thus death of the oocyte occurred even at lower concentrations than that induced by C or EGCg. Although EGCg produced H2O2 in aqueous solution, OC did not. This newly synthesized catechin derivative OC possibly binds to the lipid membrane more strongly than does C, Ecg, or EGCg and as a result perturbs the membrane structure.     

Characterization and molecular mapping of EMS-induced brittle culm mutants of diploid wheat (<Emphasis Type="Italic">Triticum monococcum</Emphasis> L.)

Diploid wheat (Triticum monococcum L, A^mA^m) is an ideal material for induced mutations which can be easily characterized and transferred to polyploid wheats. The EMS-induced brittle culm mutants, brc1, brc2, and brc3 used in the present investigation, were isolated from T. monococcum. All the brittle mutants had brittle roots, leaves, leaf sheaths, culms, and spikes, and were also susceptible to lodging. The mutants had 47–57% reduced α-cellulose in the secondary cell walls than that of T. monococcum indicating that all of them had defective synthesis of cellulose. All the mutants were monogenic recessive. Bulk segregation analysis of the mutants, using A^m genome anchored SSR markers in their F ₂ populations with T. boeoticum, located the mutants, brc1, brc2, and brc3 on chromosome 6A, 3A, and 1A of T. monococcum, respectively. Molecular analysis of the putatively linked markers showed that brc1 mapped on chromosome 6AS between Xbarc37 and Xbarc113 markers, brc2 on chromosome 3AL between Xcfd62 and Xcfa2170 markers whereas brc3 mapped on chromosome 1AL between Xgwm135 and Xwmc470 markers. Isolation and mapping of three different brittle culm mutants in wheat for the first time shows that there might be many more genes in wheat which affect synthesis and deposition of cellulose.     

Regeneration in sugarcane via somatic embryogenesis and genomic instability in regenerated plants

In the present study, embryogenic calli of sugarcane variety BL4 were induced using 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin in different concentrations and combinations. In contrast to earlier studies, embryogenic callus sectors were identified and isolated microscopically within 1–2 weeks. Subsequently, 51 media formulations were used for regeneration of proliferated embryogenic callus, using MS medium supplemented with three different cytokinins [kinetin, 6-Benzylamino purine (BAP), and thidiazuron (TDZ)] and auxins (IAA/NAA and IBA) in different combination and concentrations. After acclimatization, the genomic DNA of regenerated plants was studied to explore the insertion polymorphism of transposable elements in order to ascertain the variation among somaclones. Though low concentration of kinetin with 2,4-D was found supportive to embryogenic callus development, the highest number of regenerated plantlets was observed using BAP (1 μM), however the plantlets had very low fresh weight (2.2 g). Conversely, TDZ alone supported a significant increase in the number of plantlets regenerated (38–40) with higher fresh weight. The somaclones generated during this study showed considerable positional polymorphism of activator-like transposable elements possibly due to the stress associated with in vitro culture. This study provides a procedure to produce regenerated sugarcane plants from embryogenic callus in a relatively short time.