Ethical,legal and social aspects of the approach in Sudan

The global malaria situation, especially in Africa, and the problems frequently encountered in chemical control of vectors such as insecticide resistance, emphasize the urgency of research, development and implementation of new vector control technologies that are applicable at regional and local levels. The successful application of the sterile insect technique (SIT) for the control of the New World screwworm Cochliomyia hominivorax and several species of fruit flies has given impetus to the use of this method for suppression or elimination of malaria vectors in some areas of Africa including Northern State of Sudan. The research and development phase of the Northern State feasibility study has been started. Sudanese stakeholders are working side-by-side with the International Atomic Energy Agency in the activities of this important phase. Several ethical, legal and social issues associated with this approach arose during this phase of the project. They need to be seriously considered and handled with care. In this paper, these issues are described, and the current and proposed activities to overcome potential hurdles to ensure success of the project are listed.     

Activation propetties of the inward-recifying potassium channel on mammalian heart cells

Summary The early phase of activation of the inward-rectifying potassium channel is studied on single cells from guinea-pig heart. The current is quasi-instantaneous when it is outward, but activates with time when it is inward. This relaxation is exponential and its time-constant decreases with hyperpolarization. TheI/V curve reflects a strong inward rectification and has a negative slope conductance on depolarization. Similar results were recorded in the absence of sodium, calcium, chloride ions and in isotonic potassium. Cesium slows down the phase of activation, and eventually appears to block the channels by suppression of the activation. Barium, conversely, does not affect the activation, but promotes an inactivation of this current, which blocks it. These results are independent on the cells' dissociation method. They suggest that this current is the inward rectifier, calledI _K1 on heart. Its activation curve suggests that the inward and outward currents are flowing through the same channels. The inward rectifier is time-and voltage-dependent on heart as on other tissues. The effects of cesium and barium are also similar. The importance of its negative slope conductance is discussed.     

Preparation and characterization of activated carbon from sunflower seed oil residue via microwave assisted K2CO3 activation

Sunflower seed oil residue, a by-product of sunflower seed oil refining, was utilized as a feedstock for preparation of activated carbon (SSHAC) via microwave induced K(2)CO(3) chemical activation. SSHAC was characterized by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption and elemental analysis. Surface acidity/basicity was examined with acid-base titration, while the adsorptive properties of SSHAC were quantified using methylene blue (MB) and acid blue 15 (AB). The monolayer adsorption capacities of MB and AB were 473.44 and 430.37 mg/g, while the Brunauer-Emmett-Teller surface area, Langmuir surface area and total pore volume were 1411.55 m(2)/g, 2137.72 m(2)/g and 0.836 cm(3)/g, respectively. The findings revealed the potential to prepare high surface area activated carbon from sunflower seed oil residue by microwave irradiation.     

Experimental transmission and tissue tropism of Macrobrachium rosenbergii nodavirus (MrNV) and its associated extra small virus (XSV)

White tail disease (WTD) was found to be a serious problem in hatcheries and nursery ponds of Macrobrachium rosenbergii in India. The causative organisms have been identified as M. rosenbergii nodavirus (MrNV) and its associated extra small virus (XSV). Experimentally transmitted to healthy animals, they caused 100% mortality in post-larvae but failed to cause mortality in adult prawns. The RT-PCR assay revealed the presence of both viruses in moribund post-larvae and in gill tissue, head muscle, stomach, intestine, heart, hemolymph, pleopods, ovaries and tail muscle, but not in eyestalks or the hepatopancreas of experimentally infected adult prawns. The presence of these viruses in ovarian tissue indicates the possibility of vertical transmission. Pleopods have been found to be a suitable organ for detecting these viruses in brooders using the RT-PCR technique.     

Salt tolerance of a cash crop halophyte Suaeda fruticosa: biochemical responses to salt and exogenous chemical treatments

Suaeda fruticosa Forssk is a leaf succulent obligate halophyte that produces numerous seeds under saline conditions. Seeds are a good source of high quality edible oil and leaves are capable of removing substantial amount of salt from the saline soil besides many other economic usages. Little is known about the biochemical basis of salt tolerance in this species. We studied some biochemical responses of S. fruticosa to different exogenous treatments under non-saline (0 mM), moderate (300 mM) or high (600 mM) NaCl levels. Eight-week-old seedlings were sprayed twice a week with distilled water, hydrogen peroxide (H₂O₂, 100 μM), glycine betaine (GB, 10 mM), or ascorbic acid (AsA, 20 mM) for 30 days. At moderate (300 mM) NaCl, leaf Na⁺, Ca²⁺ and osmolality increased, along with unchanged ROS and antioxidant enzyme activities, possibly causing a better plant growth. Plants grew slowly at 600 mM NaCl to avoid leaf Na⁺ buildup relative to those at 300 mM NaCl. Exogenous application of distilled water and H₂O₂ improved ROS scavenging mechanisms, although growth was unaffected. ASA and GB alleviated salt-induced growth inhibition at 600 mM NaCl through enhancing the antioxidant defense system and osmotic and ion homeostasis, respectively.     

CNIH4 Interacts with Newly Synthesized GPCR and Controls Their Export from the Endoplasmic Reticulum

The molecular mechanisms regulating G protein‐coupled receptors (GPCRs) trafficking from their site of synthesis in the endoplasmic reticulum (ER) to their site of function (the cell surface) remain poorly characterized. Using a bioluminescence resonance energy transfer‐based proteomic screen, we identified a novel GPCR‐interacting protein; the human cornichon homologue 4 (CNIH4). This previously uncharacterized protein is localized in the early secretory pathway where it interacts with members of the 3 family of GPCRs. Both overexpression and knockdown expression of CNIH4 caused the intracellular retention of GPCRs, indicating that this ER‐resident protein plays an important role in GPCR export. Overexpression of CNIH4 at low levels rescued the maturation and cell surface expression of an intracellularly retained mutant form of the β2‐adrenergic receptor, further demonstrating a positive role of CNIH4 in GPCR trafficking. Taken with the co‐immunoprecipitation of CNIH4 with Sec23 and Sec24, components of the COPII coat complex responsible for ER export, these data suggest that CNIH4 acts as a cargo‐sorting receptor, recruiting GPCRs into COPII vesicles .      

A Ca(v)3.2/syntaxin-1A signaling complex controls T-type channel activity and low-threshold exocytosis

T-type calcium channels represent a key pathway for Ca(2+) entry near the resting membrane potential. Increasing evidence supports a unique role of these channels in fast and low-threshold exocytosis in an action potential-independent manner, but the underlying molecular mechanisms have remained unknown. Here, we report the existence of a syntaxin-1A/Ca(v)3.2 T-type calcium channel signaling complex that relies on molecular determinants that are distinct from the synaptic protein interaction site (synprint) found in synaptic high voltage-activated calcium channels. This interaction potently modulated Ca(v)3.2 channel activity, by reducing channel availability. Other members of the T-type calcium channel family were also regulated by syntaxin-1A, but to a smaller extent. Overexpression of Ca(v)3.2 channels in MPC 9/3L-AH chromaffin cells induced low-threshold secretion that could be prevented by uncoupling the channels from syntaxin-1A. Altogether, our findings provide compelling evidence for the existence of a syntaxin-1A/T-type Ca(2+) channel signaling complex and provide new insights into the molecular mechanism by which these channels control low-threshold exocytosis.     

Computational studies of gramicidin permeation: An entryway sulfonate enhances cation occupancy at entry sites

The impact on the cation-transport free-energy profile of replacing the C-terminal ethanolamine in the gramicidin A channel with a taurine residue is studied using molecular dynamics simulations of gramicidin A (1JNO) embedded in a lipid bilayer (DMPC) with 1 mol/kg NaCl saline solution. The potential of mean force for ion transport is obtained by umbrella sampling. The presence of a negatively charged sulfonate group at the entrance of the gramicidin channel affects the depth and the location of the binding sites, producing a strong attraction for the cations in the bulk. The potential of mean force by the sulfonate acting directly through electrostatics and van der Waals interactions on the test ion is highly modulated by indirect effects (i.e., sulfonate effects on other components of the system that, in turn, affect the ion free-energy profile in the channel). Because the “entry” sites are located symmetrically at both entry and exit of the channel, the deeper free-energy wells should inhibit exit. Given that the channel has increased conductance experimentally, the simulation results suggest that the channel conductance is normally entry limited.     

Antioxidant defense responses: physiological plasticity in higher plants under abiotic constraints

Environmental stresses (salinity, drought, heat/cold, light and other hostile conditions) may trigger in plants oxidative stress, generating the formation of reactive oxygen species (ROS). These species are partially reduced or activated derivatives of oxygen, comprising both free radical and non-radical (H₂O₂) forms, leading to cellular damage, metabolic disorders and senescence processes. In order to overcome oxidative stress, plants have developed two main antioxidants defense mechanisms that can be classified as non-enzymatic and enzymatic systems. The first class (non-enzymatic) consists of small molecules such as vitamin (A, C and E), glutathione, carotenoids and phenolics that can react directly with the ROS by scavenging them. Second class is represented by enzymes among them superoxide dismutase, peroxidase and catalase which have the capacity to eliminate superoxide and hydrogen peroxide. In this review, we have tried to explore the related works, which have revealed the changes in the basic antioxidant metabolism of plants under various abiotic constraints.