In vitro organogenesis and plant regeneration from leaves of Solanum candidum Lindl,S. quitoense Lam. (naranjilla) and S. sessiliflorum Dunal

Adventitious shoots and roots were regenerated from leaf segments of 3 Solanum species: S. candidum Lindl., S. quitoense Lam. and S. sessiliflorum Dunal. Leaf explants differentiated shoots on modified MS medium supplemented with 23–163 M kinetin and 0–5.7 µM indoleacetic acid (IAA). Excised shoots were induced to form roots by transfer to media with benzyladenine (BA) and naphthaleneacetic acid (NAA) at 0.09 and 0.11 µM respectively for S. quitoense and 0.01 µM NAA for S. candidum and S. sessiliflorum. Adventitious roots were produced directly from leaf explants with 0–140 µM kinetin and 0–5.7 µM IAA in combination. Rooted plants were successfully established in the greenhouse.     

Trimethyloxonium modification of single batrachotoxin-activated sodium channels in planar bilayers. Changes in unit conductance and in block by saxitoxin and calcium

Single batrachotoxin-activated sodium channels from rat brain were modified by trimethyloxonium (TMO) after incorporation in planar lipid bilayers. TMO modification eliminated saxitoxin (STX) sensitivity, reduced the single channel conductance by 37%, and reduced calcium block of inward sodium currents. These effects always occurred concomitantly, in an all-or-none fashion. Calcium and STX protected sodium channels from TMO modification with potencies similar to their affinities for block. Calcium inhibited STX binding to rat brain membrane vesicles and relieved toxin block of channels in bilayers, apparently by competing with STX for the toxin binding site. These results suggest that toxins, permeant cations, and blocking cations can interact with a common site on the sodium channel near the extracellular surface. It is likely that permeant cations transiently bind to this superficial site, as the first of several steps in passing inward through the channel.     

Inflorescences: concepts,function, development and evolution

Background

Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant''s reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits. At fruit maturity they support the fruits prior to dispersal, and facilitate effective fruit and seed dispersal. From a structural point of view, inflorescences have played important roles in systematic and phylogenetic studies. As functional units they facilitate reproduction, and are largely shaped by natural selection.

Scope

The papers in this Special Issue bridge the gap between structural and functional approaches to inflorescence evolution. They include a literature review of inflorescence function, an experimental study of inflorescences as essential contributors to the display of flowers, and two papers that present new methods and concepts for understanding inflorescence diversity and for dealing with terminological problems. The transient model of inflorescence development is evaluated in an ontogenetic study, and partially supported. Four papers present morphological and ontogenetic studies of inflorescence development in monophyletic groups, and two of these evaluate the usefulness of Hofmeister''s Rule and inhibitory fields to predict inflorescence structure. In the final two papers, Bayesian and Monte-Carlo methods are used to elucidate inflorescence evolution in the Panicoid grasses, and a candidate gene approach is used in an attempt to understand the evolutionary genetics of inflorescence evolution in the genus Cornus (Cornaceae). Taken as a whole, the papers in this issue provide a glimpse of contemporary approaches to the study of the structure, development, and evolution of inflorescences, and suggest fruitful new directions for research.     

Bacteria in cancer therapy: a novel experimental strategy

Resistance to conventional anticancer therapies in patients with advanced solid tumors has prompted the need of alternative cancer therapies. Moreover, the success of novel cancer therapies depends on their selectivity for cancer cells with limited toxicity to normal tissues. Several decades after Coley's work a variety of natural and genetically modified non-pathogenic bacterial species are being explored as potential antitumor agents, either to provide direct tumoricidal effects or to deliver tumoricidal molecules. Live, attenuated or genetically modified non-pathogenic bacterial species are capable of multiplying selectively in tumors and inhibiting their growth. Due to their selectivity for tumor tissues, these bacteria and their spores also serve as ideal vectors for delivering therapeutic proteins to tumors. Bacterial toxins too have emerged as promising cancer treatment strategy. The most potential and promising strategy is bacteria based gene-directed enzyme prodrug therapy. Although it has shown successful results in vivo yet further investigation about the targeting mechanisms of the bacteria are required to make it a complete therapeutic approach in cancer treatment.     

A Highlights from MBoC Selection: Peptide TFP5/TP5 derived from Cdk5 activator P35 provides neuroprotection in the MPTP model of Parkinson’s disease

Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by the loss of dopamine neurons in the substantia nigra, decreased striatal dopamine levels, and consequent extrapyramidal motor dysfunction. Recent evidence indicates that cyclin-dependent kinase 5 (Cdk5) is inappropriately activated in several neurodegenerative conditions, including PD. To date, strategies to specifically inhibit Cdk5 hyperactivity have not been successful without affecting normal Cdk5 activity. Previously we reported that TFP5 peptide has neuroprotective effects in animal models of Alzheimer’s disease. Here we show that TFP5/TP5 selective inhibition of Cdk5/p25 hyperactivation in vivo and in vitro rescues nigrostriatal dopaminergic neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP/MPP+) in a mouse model of PD. TP5 peptide treatment also blocked dopamine depletion in the striatum and improved gait dysfunction after MPTP administration. The neuroprotective effect of TFP5/TP5 peptide is also associated with marked reduction in neuroinflammation and apoptosis. Here we show selective inhibition of Cdk5/p25 ­hyperactivation by TFP5/TP5 peptide, which identifies the kinase as a potential therapeutic target to reduce neurodegeneration in Parkinson’s disease.     

Balanced complex chromosomal rearrangements (BCCR) with at least three chromosomes and three or more breakpoints: report of three new cases

Balanced complex chromosomal rearrangements (BCCR) encompass a heterogeneous group of rare chromosomal aberrations. In this paper, we report three cases of BCCRs. In two the probands were referred for either genetic counseling or prenatal management. One case was ascertained after chromosome analysis performed because of psychiatric manifestations; this was an isolated finding. We also outline the molecular cytogenetic techniques, which were essential in confirming and precisely delineating the BCCRs identified in these patients. In addition the various aspects of genetic counseling for this type of chromosomal rearrangement, highlighting the details particular to each individual case are discussed. We discuss the classification for this type of chromosomal mutation.     

Analysis of factors that influence energy expenditure in honeyeaters (Meliphagidae)

The energy expenditure of the tūī (Prosthemadera novaeseelandiae), a meliphagid endemic to New Zealand, was measured and compared with 20 species of honeyeaters (family Meliphagidae) to determine whether its expenditure is influenced either by life in a moist, temperate climate or an island residence. Body mass in the honeyeaters accounted for 91.5% of the variation in basal rate. The combination of body mass, climate and the maximal limit to an altitudinal distribution explained 98.6% of the variation in basal rate with tropical, low-altitude species having the highest mass-independent rate. The basal rates of meliphagids in tropical highlands are similar to those in temperate lowlands, which may reflect similar food supplies. The tūī mass-independent expenditure appears to reflect an active lifestyle in a temperate climate with no evidence that an island residence influenced its rate, whereas sedentary birds on New Zealand have responded to island life with a depressed basal rate. An effective analysis of the variation in energy expenditure requires the inclusion of the ecological and behavioural characteristics that distinguish species.     

Acceleration Workspace of Cooperating Multi-Finger Robot Systems

We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperating multi-finger robots is derived considering the force and acceleration relationships between the fingers and the object to be handled. From the dynamic equation, maximum translational and rotational acceleration bounds of an object are calculated under given constraints of contact conditions, configurations of fingers, and bounds on the torques of joint actuators for each finger. Here, the rotational acceleration bounds can be applied as an important manipulability index when the multi-finger robot grasps an object. To verify the proposed method, we used a set of case studies with a simple multi-finger mechanism system. The achievable acceleration boundary in task space can be obtained successfully with the proposed method and the acceleration boundary depends on the configurations of fingers.