Wildlife utilization: use it or lose it — a Kenyan perspective

The history, present status, plans for the future and constraints of consumptive utilization of wildlife in Kenya are discussed. Such utilization is considered to be a viable development option and has positive aspects for conservation of the environment and animals. It is proposed that illegal consumptive utilization is at such a level in the country that if it is not brought under control the wildlife population will decline catastrophically. There are numerous constraints of a legal and infrastructural nature which will reduce the potential of wildlife utilization, especially in the short term. Community knowledge of sustainable utilization methods is lacking as is, to a large extent, governmental and non-governmental support for such activities. The Kenya Wildlife Service is the body empowered to act in this area and it is funded to carry a community programme forward but implementation will require a massive locally-driven initiative without bureaucratic interference. Game ranching and farming are developing but involve only a small sector of the community and at a relatively low level compared with Southern Africa. Some practical and veterinary aspects are briefly discussed.     

Implications of exercise training in mtDNA defects--use it or lose it?

Whether regular exercise is beneficial or should be avoided is a question currently unsettled in patients with heteroplasmic mitochondrial DNA (mtDNA) disorders of skeletal muscle. Deleterious effects of habitual physical inactivity superimposed upon impaired mitochondrial oxidative phosphorylation may contribute to varying degrees of exercise intolerance in these patients. Endurance exercise training is widely known to improve exercise capacity in healthy subjects and various chronic-disease patient populations. Although we have shown that beneficial physiological and biochemical responses to training increase exercise tolerance in patients with mtDNA defects, knowledge of the muscle adaptive response to endurance training within the setting of mitochondrial heteroplasmy remains limited. In order to determine advisability of endurance training as therapy, it remains to be established whether potential endurance training-induced increases in mutant mtDNA levels may be offset by increases in absolute wild-type mtDNA levels, and whether chronic inactivity leads to a selective down-regulation of wild-type mtDNA. Resistance training utilizes a different adaptive exercise approach to induce the transfer of normal mitochondrial templates from satellite cells to mature muscle fibers of patients with sporadic mtDNA disorders. The efficacy and safety of this approach needs to be further established. Our current inability to clearly advise patients to "use it or lose it" underscores the immediate urgency of studying the effects of exercise on skeletal muscle of patients with heteroplasmic mtDNA defects.     

The plastid in Apicomplexa: what use is it?

An extrachromosomal genome of between 27 and 35 kb has been described in several apicomplexan parasites including Plasmodium falciparum and Toxoplasma gondii. Examination of sequence data proved the genomes to be a remnant plastid genome, from which all genes encoding photosynthetic functions had been lost. Localisation studies had shown that the genome was located within a multi-walled organelle, anterior to the nucleus. This organelle had been previously described in ultrastructural studies of several genera of apicomplexa, but no function had been attributed to it. This invited review describes the evolution of knowledge on the apicomplexan plastid, then discusses current research findings on the likely role of the plastid in the Apicomplexa. How the plastid may be used to effect better drug treatments for apicomplexan diseases, and its potential as a marker for investigating phylogenetic relationships among the Apicomplexa, are discussed.     

Regulated exocytosis in chromaffin cells and cytotoxic T lymphocytes: How similar are they?

Chromaffin cells from the adrenal medulla secrete catecholamines into the blood stream as part of the fight-or-flight response. Cytotoxic T lymphocytes from the immune system release cytotoxic substances to kill antigen-presenting cells. While at first glance these two cell types do not seem to have much in common, evidence from human diseases indicates that the molecular mechanisms of exocytosis of the respective granules share many similar features. In this review we highlight the similarities and differences of individual aspects of granule maturation and release in both cell types. In addition, we discuss established and putative molecules involved in distinct steps and suggest technical approaches which might facilitate future studies in chromaffin cells and cytotoxic T lymphocytes.     

Tension in fibrils suppresses their enzymatic degradation – A molecular mechanism for ‘use it or lose it’

Tissue homeostasis depends on a balance of synthesis and degradation of constituent proteins, with turnover of a given protein potentially regulated by its use. Extracellular matrix (ECM) is predominantly composed of fibrillar collagens that exhibit tension-sensitive degradation, which we review here at different levels of hierarchy. Past experiments and recent proteomics measurements together suggest that mechanical strain stabilizes collagen against enzymatic degradation at the scale of tissues and fibrils whereas isolated collagen molecules exhibit a biphasic behavior that depends on load magnitude. Within a Michaelis-Menten framework, collagenases at constant concentration effectively exhibit a low activity on substrate fibrils when the fibrils are strained by tension. Mechanisms of such mechanosensitive regulation are surveyed together with relevant interactions of collagen fibrils with cells.     

β-Glucuronidase activity in human T and B lymphocytes and the Tμ and Tγ subpopulations

Summary The -glucuronidase staining characteristics of isolated T cell populations and the T and T enriched fractions derived of them were studied. T lymphocytes were obtained from purified T lymphocytes by ox-IgG rosette sedimentation. The rosette-forming cells in the pellet were referred to as T lymphocytes, whereas the lymphocytes in the interface were referred to as T depleted or T lymphocytes. B cells were studied on rosetted mononuclear cells with either mouse erythrocytes or with Staphylococcus Aureus (Cowan I) bacteria, after a preceeding polyvalent anti-human Ig treatment of the cells. While B cells showed mostly no reactivity, T and T cells were respectively characterised by a dot-like and granular pattern of reactivity. These findings are in agreement with those observed by others after -naphthyl-acetate esterase or acid phosphatase staining. Within the T lymphocyte fraction, the T non-, non lymphocytes seemed to have a granular pattern of reactivity. The same staining pattern was found in non-B, non-T lymphocytes.     

Healthy Aging: Antioxidants,Uncouplers and/or Telomerase?

Molecular Biology - The free radical theory of aging was proposed in 1956. Although it does not fully describe the mechanisms of aging, it is generally accepted that reactive oxygen species (ROS)...     

Telomerase regulation in hematological cancers: A matter of stemness?

Human telomerase is a nuclear ribonucleoprotein enzyme complex that catalyzes the synthesis and extension of telomeric DNA. This enzyme is highly expressed and active in most malignant tumors while it is usually not or transiently detectable in normal somatic cells, suggesting that it plays an important role in cellular immortalization and tumorigenesis. As most leukemic cells are generally telomerase-positive and have often shortened telomeres, our understanding of how telomerase is deregulated in these diseases could help to define novel therapies targeting the telomere/telomerase complex. Nonetheless, considering that normal hematopoietic stem cells and some of their progeny do express a functional telomerase, it is tempting to consider such an activity in leukemias as a sustained stemness feature and important to understand how telomere length and telomerase activity are regulated in the various forms of leukemias.     

CD3γ-independent pathways in TCR-mediated signaling in mature T and iNKT lymphocytes

Antigen recognition by T-lymphocytes through the T-cell antigen receptor, TCR–CD3, is a central event in the initiation of an immune response. CD3 proteins may have redundant as well as specific contributions to the intracellular propagation of TCR-mediated signals. However, to date, the relative role that each CD3 chain plays in signaling is controversial. In order to examine the roles of CD3γ chain in TCR signaling, we analyzed proximal and distal signaling events in human CD3γ^−/− primary and Herpesvirus saimiri (HVS)-transformed T cells. Following TCR–CD3 engagement, certain early TCR signaling pathways (ZAP-70, ERK, p38 and mTORC2 phosphorylation, and actin polymerization) were comparable with control HVS-transformed T cells. However, other signaling pathways were affected, such TCRζ phosphorylation, indicating that the CD3γ chain contributes to improve TCR signaling efficiency and survival. On the other hand, CD3γ^−/− primary invariant NKT cells (iNKT cells) showed a normal expansion in response to alpha-galactosylceramide (α-GalCer) and TCRVβ11^bright iNKT cells were preferentially selected in this in vitro culture system, perhaps as a consequence of selective events in the thymus. Our results collectively indicate that a TCR lacking CD3γ can propagate a number of signals through the remaining invariant chains, likely the homologous CD3δ chain, which replaces it at the mutant TCR.     

The molecular biology of recombination in Mycobacteria: what do we know and how can we use it?

Recombination is a ubiquitous genetic process which results in the exchange of DNA between two substrates. Homologous recombination occurs between DNA species with identical sequence whereas illegitimate recombination can occur between DNA with very little or no homology. Site-specific recombination is often used by temperate phages to stably integrate into bacterial chromosomes. Characterisation of the mechanisms of recombination in mycobacteria has mainly focussed on RecA-dependent homologous recombination and phage-directed site-specific recombination. In contrast the high frequency of illegitimate recombination in slow-growing mycobacteria has not been explained. The role of DNA repair in dormancy and infection have not yet been fully established, but early work suggests that RecA-mediated pathways are not required for virulence. All three recombination mechanisms have been utilised in developing genetic techniques for the analysis of the biology and pathogenesis of mycobacteria. A recently developed method for studying essential genes will generate further insights into the biology of these important organisms.     

Apoptosis: why and how does it occur in biology?

The literature on apoptosis has grown tremendously in recent years, and the mechanisms that are involved in this programmed cell death pathway have been enlightened. It is now known that apoptosis takes place starting from early development to adult stage for the homeostasis of multicellular organisms, during disease development and in response to different stimuli in many different systems. In this review, we attempted to summarize the current knowledge on the circumstances and the mechanisms that lead to induction of apoptosis, while going over the molecular details of the modulator and mediators of apoptosis as well as drawing the lines between programmed and non-programmed cell death pathways. The review will particularly focus on Bcl-2 family proteins, the role of different caspases in the process of apoptosis, and their inhibitors as well as the importance of apoptosis during different disease states. Understanding the molecular mechanisms involved in apoptosis better will make a big impact on human diseases, particularly cancer, and its management in the clinics.     

Estrogens and obesity: is it all in our heads?

Estrogens have preventative effects on weight gain and associated comorbidities, but the tissue-specific targets remain unknown. Here, Xu et al. (2011) demonstrate that ablation of estrogen signaling in two populations of hypothalamic neurons leads to weight gain and subsequent metabolic dysregulation and could be important target sites of estrogen actions.     

Acoustic and magnetic communication in plants: Is it possible?

Over the last two decades, important insights into our understanding of plant ecology and the communicative nature of plants have not only confirmed the existence of a wide range of communication means used by plants, but most excitingly have indicated that more modalities remain to be discovered. In fact, we have recently found that seeds and seedlings of the chili plant, Capsicum annuum, are able to sense neighbors and identify relatives using alternative mechanisms beyond previously studied channels of plant communication. In this addendum, we offer a hypothetical mechanistic explanation as to how plants may do this by quantum-assisted magnetic and/or acoustic sensing and signaling. If proven correct, this hypothesis prompts for a re-interpretation of our current understanding of plasticity in germination and growth of plants and more generally, calls for developing a new perspective of these biological phenomena.     

What is geometric information and how do animals use it?

Unlike investigations of animals’ use of spatial cues such as landmarks, studies of sensitivity to the geometry of surfaces in an enclosure have proceeded mostly as an attempt to explain a laboratory finding with few direct tests of how animals use such a cue in nature. In this brief review, I discuss the current debate over whether global or local information from the enclosure drives the typical rotational error pattern in such studies. A consideration of the form and function of geometric cues in natural settings suggests that the natural boundaries for which arena walls are considered analogous might better be thought as landmarks. With a clearer picture of what geometric information is and how it might be used in nature, the generality of findings from laboratory studies of geometry enclosure can be better assessed.     

Remission in psoriatic arthritis: is it possible and how can it be predicted?

Introduction

Since remission is now possible in psoriatic arthritis (PsA) we wished to examine remission rates in PsA patients following anti tumour necrosis factor alpha (TNFα) therapy and to examine possible predictors of response.

Methods

Analysis of a prospective patient cohort attending a biologic clinic, between November 2004 and March 2008, was performed prior to commencing therapy and at regular intervals. Baseline clinical characteristics including demographics, previous disease-modifying antirheumatic drug (DMARD) response, tender and swollen joint counts, early morning stiffness, pain visual analogue score, patient global assessment, C reactive protein (CRP) and health assessment questionnaire (HAQ) were collected.

Results

A total of 473 patients (152 PsA; 321 rheumatoid arthritis (RA)) were analyzed. At 12 months remission, defined according to the disease activity score using 28 joint count and CRP (DAS28-CRP), was achieved in 58% of PsA patients compared to 44% of RA patients, significant improvement in outcome measures were noted in both groups (P < 0.05). Analysis of a subgroup of PsA and RA patients matched for DAS28-CRP at baseline also showed higher numbers of PsA patients achieving remission. Linear regression analysis identified the HAQ at baseline as the best predictor of remission in PsA patients (P < 0.001).

Conclusions

DAS28 remission is possible in PsA patients at one year following anti-TNF therapy, at higher rates than in RA patients and is predicted by baseline HAQ.