Improved Protocol for the Synthesis of Flexibly Protected Morpholino Monomers from Unprotected Ribonucleosides

An inexpensive and much improved protocol has been developed for the synthesis of protected morpholino monomers from unprotected ribonucleosides in high overall yield, using oxidative glycol cleavage and reductive amination strategy. Unlike the previous methods, the present strategy allows installing the exocyclic amine protections at a later stage, and thus avoids the use of expensive, or commercially unavailable, exocyclic amine-protected ribonucleosides as starting materials. To demonstrate the flexibility of the present method in choosing protecting groups, the monomers have been protected with several such groups of different deblocking properties at the exocyclic amine position.     

Nicotinamide Adenine Dinucleotide Phosphate Phosphatase Facilitates Dark Reduction of Nitrate: Regulation by Nitrate and Ammonia

Leaves of 15 - 30-d-old plants of sunflower and jute were harvested at 10.00 or 23.00 (local time) and measured immediately, or those harvested at 10.00 were incubated for one hour in sunlight either in water or 5 mM methionine sulfoximine (MSX) solution and then for three hours in dark either in water or 15 mM KNO3 solution. Nitrate feeding during dark incubation, in general, increased nitrate reductase (NR) and nitrite reductase (NiR) activities, and NADH and soluble sugar contents. Increase in tissue nitrate concentration in MSX fed but not in control samples suggested reduction of nitrate in dark. NADPH-dependent NR activity increased considerably upon feeding with nitrate in dark. Concomitantly, NADPH phosphatase activity was also increased in nitrate treated, dark incubated leaves. It is proposed that nitrate regulates dark nitrate reduction by facilitating generation of NADH from NADPH by NADPH phosphatase. High amounts of ammonia accumulated in MSX treated, but not in control leaves, upon dark incubation. Relative activities of NR and NADPH phosphatase, and amounts of soluble sugar and NADH were low in MSX fed samples compared to that of control. So, high amount of ammonia might partially repress NADPH phosphatase and consequently deprive NR of reducing equivalents. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification of antisense nucleic acid hybridization sites in mRNA molecules with self-quenching fluorescent reporter molecules

We describe a physical mRNA mapping strategy employing fluorescent self-quenching reporter molecules (SQRMs) that facilitates the identification of mRNA sequence accessible for hybridization with antisense nucleic acids in vitro and in vivo, real time. SQRMs are 20–30 base oligodeoxynucleotides with 5–6 bp complementary ends to which a 5′ fluorophore and 3′ quenching group are attached. Alone, the SQRM complementary ends form a stem that holds the fluorophore and quencher in contact. When the SQRM forms base pairs with its target, the structure separates the fluorophore from the quencher. This event can be reported by fluorescence emission when the fluorophore is excited. The stem–loop of the SQRM suggests that SQRM be made to target natural stem–loop structures formed during mRNA synthesis. The general utility of this method is demonstrated by SQRM identification of targetable sequence within c-myb and bcl-6 mRNA. Corresponding antisense oligonucleotides reduce these gene products in cells.     

The role of CD95 and CD95 ligand in cancer

CD95 (Fas/APO-1) and its ligand, CD95L, have long been viewed as a death receptor/death ligand system that mediates apoptosis induction to maintain immune homeostasis. In addition, these molecules are important in the immune elimination of virus-infected cells and cancer cells. CD95L was, therefore, considered to be useful for cancer therapy. However, major side effects have precluded its systemic use. During the last 10 years, it has been recognized that CD95 and CD95L have multiple cancer-relevant nonapoptotic and tumor-promoting activities. CD95 and CD95L were discovered to be critical survival factors for cancer cells, and were found to protect and promote cancer stem cells. We now discuss five different ways in which inhibiting or eliminating CD95L, rather than augmenting, may be beneficial for cancer therapy alone or in combination with standard chemotherapy or immune therapy.     

Genetic analysis of panicle and physiological traits in hill rice grown in mid altitudes of northeastern India

This paper aims to discover the genetic parameters underlying the physiological efficiency and panicle characters of hill rice plants. In order to improve these characters, it is crucial to learn the nature and magnitude of gene action involved in inheritance of panicle and physiological traits. With this purpose, we combined a line × tester analysis of crosses involving local cultivars and indigenous and exotic germplasm grown at the northeastern hill region of India. From the study it follows that number of tillers per hill, number of ear bearing tillers per hill, panicle length, panicle weight, number of grains per panicle, number of filled grains per panicle, pollen fertility, spikelet fertility, leaf area index, total chlorophyll content and harvest index were mainly under the control of non-additive gene action, while total dry matter accumulation and grain yield per plant were under the control of additive gene action. The genotypes DR 92, Ngoba, IET 16451 and UPR 1425-1-1-4 were identified as superior parents with high performance and significant general combining ability effects. For heterosis breeding six cross combinations, viz., DR 92/IET 16471, DR 92/UPR 1425-1-1-4, DR 92/IET 15482, Ngoba/IET 16469, Ngoba/H274-27-24, Manipuri/IET 16451, and for recombination breeding two cross combinations, viz., DR 92/IET 16470 and Ngoba/UPR 1425- 1-1-4, were found suitable to ameliorate the panicle and physiological traits of hill rice grown in northeastern India.     

Benefits and costs of improved cookstoves: assessing the implications of variability in health, forest and climate impacts

Current attention to improved cook stoves (ICS) focuses on the "triple benefits" they provide, in improved health and time savings for households, in preservation of forests and associated ecosystem services, and in reducing emissions that contribute to global climate change. Despite the purported economic benefits of such technologies, however, progress in achieving large-scale adoption and use has been remarkably slow. This paper uses Monte Carlo simulation analysis to evaluate the claim that households will always reap positive and large benefits from the use of such technologies. Our analysis allows for better understanding of the variability in economic costs and benefits of ICS use in developing countries, which depend on unknown combinations of numerous uncertain parameters. The model results suggest that the private net benefits of ICS will sometimes be negative, and in many instances highly so. Moreover, carbon financing and social subsidies may help enhance incentives to adopt, but will not always be appropriate. The costs and benefits of these technologies are most affected by their relative fuel costs, time and fuel use efficiencies, the incidence and cost-of-illness of acute respiratory illness, and the cost of household cooking time. Combining these results with the fact that households often find these technologies to be inconvenient or culturally inappropriate leads us to understand why uptake has been disappointing. Given the current attention to the scale up of ICS, this analysis is timely and important for highlighting some of the challenges for global efforts to promote ICS.     

Catalytic function of a novel protein protochlorophyllide oxidoreductase C of Arabidopsis thaliana

In Arabidopsis thaliana Por C has been identified only on sequence homology to that of por A and por B. To demonstrate its catalytic function Arabidopsis thaliana protochlorophyllide oxidoreductase C gene (por c) that codes for the mature part of POR C protein having 335 amino acids was expressed in Escherchia coli cells. The POR C enzyme in the presence of NADPH and protochlorophyllide when incubated in dark formed a ternary complex. When it was excited at 433 nm, it had a fluorescence emission peak at 636 nm. After illumination with actinic cool white fluorescent light, a peak at 673 nm due to chlorophyllide gradually increased with concomitant decrease of 636 nm emission, demonstrating the gradual phototransformation of protochlorophyllide to chlorophyllide. The significance of differential por gene expression in light and dark among different species is discussed.     

Bifunctional Electrocatalytic Activity of Boron‐Doped Graphene Derived from Boron Carbide

A single material that can perform water oxidation and oxygen reduction reactions (ORR), also called bifunctional catalyst, represents a novel concept that emerged from recent materials research and that has led to applications in new‐generation energy‐storage systems, such as regenerative fuel cells. Here, metal/metal‐oxide free, doped graphene derived from rhombohedral boron carbide (B₄C) is demonstrated to be an effective bifunctional catalyst for the first time. B₄C, one of the hardest materials in nature next to diamond and cubic boron nitride, is converted and separated in bulk to form heteroatom (boron, B) doped graphene (BG, yield ≈7% by weight, after the first cycle). This structural conversion of B₄C to graphene is accompanied by in situ boron doping and results in the formation of an electrochemically active material from a non‐electrochemically active material, broadening its potential for application in various energy‐related technologies. The electrocatalytic efficacy of BG is studied using various voltammetric techniques. The results show a four‐electron transfer mechanism as well as a high methanol tolerance and stability towards ORR. The results are comparable to those from commercial 20 wt% Pt/C in terms of performance. Furthermore, the bifunctionality of the BG is also demonstrated by its performance in water oxidation.