Genetics of nodulation in Chickpea (Cicer arietinum L.)

Combining ability, components of genetic variance and graphic analysis revealed that nodulation in the cultivars of Chickpea (Cicer arietinum L.) under study, was predominantly under the control of non-additive gene action although substantial additive effect was also present. The crosses giving high specific combining ability effects also manifested highly significant positive heterosis. The parents F-61, Giza and Annegiri possessed mostly dominant alleles while Phule G-5, NEC-249 and N-31 possessed mostly recessive alleles having positive effect on nodule weight.     

Physiology engages with functional genomics - at last

A report on the XXXV International Congress of Physiological Sciences, held together with Experimental Biology 2005, San Diego, USA, 31 March - 6 April 2005.     

Recent excitements in protein NMR: Large proteins and biologically relevant dynamics

The advent of Transverse Relaxation Optimized SpectroscopY (TROSY) and perdeuteration allowed biomolecular NMR spectroscopists to overcome the size limitation barrier (~20 kDa) in de novo structure determination of proteins. The utility of these techniques was immediately demonstrated on large proteins and protein complexes (e.g. GroEL-GroES, ClpP protease, Hsp90-p53, 20S proteasome, etc.). Further, recent methodological developments such as Residual Dipolar Couplings and Paramagnetic Relaxation Enhancement allowed accurate measurement of long-range structural restraints. Additionally, Carr-Purcell-Meiboom-Gill (CPMG), rotating frame relaxation experiments (R₁ρ) and saturation transfer experiments (CEST and DEST) created never-before accessibility to the μs–ms timescale dynamic parameters that led to the deeper understanding of biological processes. Meanwhile, the excitement in the field continued with a series of developments in the fast data acquisition methods allowing rapid structural studies on less stable proteins. This review aims to discuss important developments in the field of biomolecular NMR spectroscopy in the recent past, i.e., in the post TROSY era. These developments not only gave access to the structural studies of large protein assemblies, but also revolutionized tools in the arsenal of today’s biomolecular NMR and point to a bright future of biomolecular NMR spectroscopy.     

Essential postmitochondrial function of p53 uncovered in DNA damage-induced apoptosis in neurons

In postmitotic sympathetic neurons, unlike most mitotic cells, death by apoptosis requires not only the release of cytochrome c from the mitochondria, but also an additional step to relieve X-linked inhibitor of apoptosis protein (XIAP)'s inhibition of caspases. Here, we examined the mechanism by which XIAP is inactivated following DNA damage and found that it is achieved by a mechanism completely different from that following apoptosis by nerve growth factor (NGF) deprivation. NGF deprivation relieves XIAP by selectively degrading it, whereas DNA damage overcomes XIAP via a p53-mediated induction of Apaf-1. Unlike wild-type neurons, p53-deficient neurons fail to overcome XIAP and remain resistant to cytochrome c after DNA damage. Restoring Apaf-1 induction in p53-deficient neurons is sufficient to overcome XIAP and sensitize cells to cytochrome c. Although a role for p53 in apoptosis upstream of cytochrome c release has been well established, this study uncovers an additional, essential role for p53 in regulating caspase activation downstream of mitochondria following DNA damage in neurons.     

Endoplasmic reticulum stress-induced apoptosis requires bax for commitment and Apaf-1 for execution in primary neurons

Apoptosis triggered by endoplasmic reticulum (ER) stress is associated with various pathophysiological conditions including neurodegenerative diseases and ischemia. However, the mechanism by which ER stress induces neuronal apoptosis remains controversial. Here we identify the pathway of apoptosis carried out in sympathetic neurons triggered to die by ER stress-inducing agent tunicamycin. We find that ER stress induces a neuronal apoptotic pathway which upregulates BH3-only genes DP5 and Puma. Importantly, we show that ER stress commits neurons to die before cytochrome c release and this commitment requires Bax activation and c-jun N-terminal kinase signaling. Furthermore, ER stress engages the mitochondrial pathway of death as neurons release cytochrome c and Apaf-1 deficiency is sufficient to block apoptosis. Our findings identify a critical function of Bax in committing neurons to ER stress-induced apoptosis and clarify the importance of the apoptosome as the non-redundant caspase activation pathway to execute neuronal apoptosis in response to ER stress.     

NMR structural characterization of the penta-peptide calpain inhibitor

Calpains are ubiquitous intracellular calcium- and thiol-dependent proteases. Their over activation, resulting in the degradation of various substrates, has been implicated in a number of cardiovascular and neurological disorders. Here, we present the first structural characterization of LSEAL penta-peptide, a potent calpain inhibitor, bound to the calmodulin-like domain of calpain. Our in vitro binding data supports the idea that domains other than calpain’s active site may be suitable targets for future development of therapeutic agents to be used to treat heart attack, traumatic brain injuries or a variety of neurodegenerative conditions, such as ischemic stroke.     

Targeting dsRNA-specific single-chain Fv antibody fragments to different cellular locations in Nicotiana tabacum L

Expression of antibodies or antibody fragments in plants is a useful tool for producing active antibody derivatives for diagnostic or pharmaceutical purposes as well as for immunomodulation. We investigated the effect of cellular expression site on the stability and yield of double-stranded RNA (dsRNA)-specific single-chain Fv-fragments (scFv) in transgenic tobacco. Two antibodies (J2 and P6) belonging to the V23(J558) heavy chain variable gene family but differing in the light chain variable domain were used. scFvs were targeted to the cytoplasm - with or without anchoring them in the plasma membrane -, into the endoplasmic reticulum (ER) and to the apoplast. Although high mRNA concentrations were detected in all cases, scFv proteins accumulated only when scFvs were made ER-resident by appropriate signal sequences. When the ER retention signal was removed to allow scFv-secretion to the apoplast, no scFv-proteins were detected. Despite the strong homology of the VH-sequences of J2 and P6 antibodies, only P6 provided a stable scFv scaffold for intracytoplasmic expression. J2-scFv could not be stabilised either by adding a C-terminal stabilisation signal or by anchoring the protein on the cytoplasmic side of the plasma membrane (PM). It was found that dsRNA-specific J2-scFvs are active in vivo and enhance Potato Virus Y induced symptoms in infected tobacco. This is the first report describing the expression and biological effect of RNA-specific antibodies in plants.     

Anticancer activity of sclerotiorin, isolated from an endophytic fungus Cephalotheca faveolata Yaguchi, Nishim. & Udagawa

Biodiversity provides critical support for drug discovery. A significant proportion of drugs are derived, directly or indirectly, from biological sources. Through high throughput screening (HTS) and bioassay-guided isolation, bioactive compound sclerotiorin has been isolated from an endophytic fungus Cephalotheca faveolata. Sclerotiorin was found to be potent anti-proliferative against different cancer cells. In this study sclerotiorin has been found to induce apoptosis in colon cancer (HCT-116) cells through the activation of BAX, and down-regulation of BCL-2, those further activated cleaved caspase-3 causing apoptosis of cancer cells.     

Caspases in ischaemic brain injury and neurodegenerative disease

The importance of caspases in developmental neuronal death is well-established. Recent data provide compelling evidence of caspase activation after ischaemic brain injury. Caspase inhibitors reduce cell death in several models of ischaemic injury. This review summarizes our current understanding of caspase function in ischaemic brain injury and examines the accumulating evidence of caspase participation in several neurodegenerative diseases. The therapeutic consequences of caspase inhibitor treatment in reducing cell death after such injury are also discussed.