Twenty-four-hour energy expenditure and basal metabolic rate measured in a whole-body indirect calorimeter in Gambian men.

By use of a respiration chamber, 24-hour energy expenditure (EE), diet-induced thermogenesis (DIT), and basal and sleeping EE were measured in 20 young rural Gambian men during the "hungry" season (weight, 60.8 +/- 1.4 kg) and in a group of 16 European men matched for body composition (weight, 66.9 +/- 1.9 kg). The 24-h EE was lower in Gambian than in European men (2047 +/- 46 vs 2635 +/- 74 kcal/d, p less than 0.001, respectively). Basal EE and sleeping EE were also lower in Gambian than in European men (1.05 +/- 0.02 vs 1.25 +/- 0.02 kcal/min and 1.0 +/- 0.02 vs 1.18 +/- 0.02 kcal/min, p less than 0.01, respectively). DIT was blunted in Gambian compared with European men (6.3 +/- 0.6% vs 12.1 +/- 0.5%, p less than 0.001 respectively). The net efficiency of walking was greater in Gambian than in European men (23.2 +/- 0.3% vs 20.1 +/- 0.4%, p less than 0.001, respectively). A low basal and sleeping EE, a reduced DIT, and a high work efficiency are important energy-sparing mechanisms in Gambian men, which allow them to cope with a marginal level of dietary intake during the hungry season.

Brain tissue properties differentiate between motor and limbic basal ganglia circuits.

Despite advances in understanding basic organizational principles of the human basal ganglia, accurate in vivo assessment of their anatomical properties is essential to improve early diagnosis in disorders with corticosubcortical pathology and optimize target planning in deep brain stimulation. Main goal of this study was the detailed topological characterization of limbic, associative, and motor subdivisions of the subthalamic nucleus (STN) in relation to corresponding corticosubcortical circuits. To this aim, we used magnetic resonance imaging and investigated independently anatomical connectivity via white matter tracts next to brain tissue properties. On the basis of probabilistic diffusion tractography we identified STN subregions with predominantly motor, associative, and limbic connectivity. We then computed for each of the nonoverlapping STN subregions the covariance between local brain tissue properties and the rest of the brain using high-resolution maps of magnetization transfer (MT) saturation and longitudinal (R1) and transverse relaxation rate (R2*). The demonstrated spatial distribution pattern of covariance between brain tissue properties linked to myelin (R1 and MT) and iron (R2*) content clearly segregates between motor and limbic basal ganglia circuits. We interpret the demonstrated covariance pattern as evidence for shared tissue properties within a functional circuit, which is closely linked to its function. Our findings open new possibilities for investigation of changes in the established covariance pattern aiming at accurate diagnosis of basal ganglia disorders and prediction of treatment outcome.

A high-fructose diet impairs basal and stress-mediated lipid metabolism in healthy male subjects

Rapport de synthèse : La consommation de boissons sucrées contenant du fructose a remarquablement augmenté ces dernières décennies et, on pense qu'elle joue un rôle important dans l'épidémie actuelle d'obésité et de troubles métaboliques. Des études faites sur des rats ont montré qu'une alimentation riche en sucre ou fructose induisait une obésité, une résistance à l'insuline, diabète, dyslipidémie et une hypertension artérielle, tandis que chez l'homme, une alimentation riche en fructose conduit, après quelques jours, au développement d'une hypertryglycémie et une résistance hépatique à l'insuline. Nous avons entrepris une étude de 7 jours d'alimentation riche en fructose ou d'une alimentation contrôlée chez six hommes en bonne santé. Les NEFA plasmatiques et la beta-hydroxybutyrate, l'oxydation nette de lipide (calorimétrie indirecte) et l'oxydation exogène de lipide (13 CO2) ont été surveillés dans des conditions basales, et après un chargement en lipide (huile d'olive marqué au 13C-trioléine), puis durant un stress mental standardisé. La clearance de lactate et les effets métaboliques de la perfusion de lactate exogène ont également été évalués. Nos résultats ont montré que l'alimentation riche en fructose diminue la concentration plasmatique de NEFA, de beta-hydroxybutyrate de même que l'oxydation des lipides dans les conditions de bases et après surcharge en lipides. De plus, l'alimentation riche en fructose amortie l'augmentation des NEFA plasmatique et l'oxydation des lipides exogènes durant le stress mental. Elle augmente également la concentration basale de lactate et la production de lactate de respectivement 31.8% et 53.8%, tandis que la clearance du lactate reste inchangée. L'injection de lactate diminue le taux des NEFA lors de l'alimentation de contrôle et l'alimentation de base, et l'oxydation nette de lipide lors de l'alimentation de contrôle et l'alimentation riche en fructose. Ces résultats indiquent que 7 jours d'alimentation riche en fructose inhibent remarquablement la lipolyse et l'oxydation des lipides. L'alimentation riche en fructose augmente aussi la production de lactate, et l'augmentation de l'utilisation de lactate peut contribuer à supprimer l'oxydation des lipides. Abstact : The effects of a 7 d high-fructose diet (HFrD) or control diet on lipid metabolism were studied in a group of six healthy lean males. Plasma NEFA and β-hydroxybutyrate concentrations, net lipid oxidation (indirect calorimetry) and exogenous lipid oxidation (13CO2 production) were monitored in basal conditions, after lipid loading (olive oil labelled with [13C] triolein) and during a standardised mental stress. Lactate clearance and the metabolic effects of an exogenous lactate infusion were also monitored. The HFrD lowered plasma concentrations of NEFA and (β-hydroxybutyrate as well as lipid oxidation in both basal and after lipid-loading conditions. In addition, the HFrD blunted the increase in plasma NEFA and exogenous lipid oxidation during mental stress. The HFrD also increased basal lactate concentrations by 31.8%, and lactate production by 53.8 %, while lactate clearance remained unchanged. Lactate infusion lowered plasma NEFA with the control diet, and net lipid oxidation with both the HFrD and control diet. These results indicate that a 7 d HFrD markedly inhibits lipolysis and lipid oxidation. The HFrD also increases lactate production, and the ensuing increased lactate utilisation may contribute to suppress lipid oxidation.

New data on the distribution and conservation status of some angiosperms of the Cape Verde Islands, W Africa

New data on the distributibn and conservation status of some angiosperms of the Cape Verde Islands, W Africa Intensive field work aud analysis of the state of biodiversity ou all islands during the years iYY.3 lo IYYY Icd lo lhc publication ol’several contributions lo the flora and vegelalion of the archipclago of Cabo Verde (Brochniann & al. 1997, Gornes & Vera-Cruz 1993. Gonles & al. I9YSa-h. 1998, Games 1997. Kilian & Leyens 1994, Leyens 1998. Leyens & Lobin 1995, Lobin & al. 1995) as well as to the compilation of the First Red Data List for the Cape Verde Islnuds (Lcyrus & Lobin 1996). the elaboration of the National Strategy for Biodiversity Conservation (SIPA 19YY) and ! compilation of all areas in urgent need of protection (Leyens unpubl. diplonla thc.\is IYYJ. Gwnes & al. iu prep.). As part UC the activities of the lnstituto National de Invcstig;u$o c Dcscnvolvitucnto Agriirio (INIDA) and the Dcpurtamcnto de GeociSncias do Institute Supcriot de Educ;u$o t ISE) iutcnsive t’icld studies were conducted PI many diffcrctu localilics OII xcvcr;~I islands. resulting in a thesis tGo~nes IY97) and several terminal study papers (Luz IYYY. Cosi;t 1994. Gonsalvez 1999). The results show that the vegetation and flora of the islands arc still IWI fully known and much more field work is needed. hllhot~gh Sanliiqw is one of lhc islands whcrc lhc firs1 holanicill iIlVcxligilliollx wcrr c:crriul WI (Wcbh 1x49. Schruidt 1x52. Chcvalicr IY35) and where uu~ny intensive field studirs wcrc

Downregulation of cannabinoid receptor 1 from neuropeptide Y interneurons in the basal ganglia of patients with Huntington's disease and mouse models.

Cannabinoid receptor 1 (CB(1) receptor) controls several neuronal functions, including neurotransmitter release, synaptic plasticity, gene expression and neuronal viability. Downregulation of CB(1) expression in the basal ganglia of patients with Huntington's disease (HD) and animal models represents one of the earliest molecular events induced by mutant huntingtin (mHtt). This early disruption of neuronal CB(1) signaling is thought to contribute to HD symptoms and neurodegeneration. Here we determined whether CB(1) downregulation measured in patients with HD and mouse models was ubiquitous or restricted to specific striatal neuronal subpopulations. Using unbiased semi-quantitative immunohistochemistry, we confirmed previous studies showing that CB(1) expression is downregulated in medium spiny neurons of the indirect pathway, and found that CB(1) is also downregulated in neuropeptide Y (NPY)/neuronal nitric oxide synthase (nNOS)-expressing interneurons while remaining unchanged in parvalbumin- and calretinin-expressing interneurons. CB(1) downregulation in striatal NPY/nNOS-expressing interneurons occurs in R6/2 mice, Hdh(Q150/Q150) mice and the caudate nucleus of patients with HD. In R6/2 mice, CB(1) downregulation in NPY/nNOS-expressing interneurons correlates with diffuse expression of mHtt in the soma. This downregulation also occludes the ability of cannabinoid agonists to activate the pro-survival signaling molecule cAMP response element-binding protein in NPY/nNOS-expressing interneurons. Loss of CB(1) signaling in NPY/nNOS-expressing interneurons could contribute to the impairment of basal ganglia functions linked to HD.

Abundant Occurrence of Basal Radial Glia in the Subventricular Zone of Embryonic Neocortex of a Lissencephalic Primate, the Common Marmoset Callithrix jacchus.

Subventricular zone (SVZ) progenitors are a hallmark of the developing neocortex. Recent studies described a novel type of SVZ progenitor that retains a basal process at mitosis, sustains expression of radial glial markers, and is capable of self-renewal. These progenitors, referred to here as basal radial glia (bRG), occur at high relative abundance in the SVZ of gyrencephalic primates (human) and nonprimates (ferret) but not lissencephalic rodents (mouse). Here, we analyzed the occurrence of bRG cells in the embryonic neocortex of the common marmoset Callithrix jacchus, a near-lissencephalic primate. bRG cells, expressing Pax6, Sox2 (but not Tbr2), glutamate aspartate transporter, and glial fibrillary acidic protein and retaining a basal process at mitosis, occur at similar relative abundance in the marmoset SVZ as in human and ferret. The proportion of progenitors in M-phase was lower in embryonic marmoset than developing ferret neocortex, raising the possibility of a longer cell cycle. Fitting the gyrification indices of 26 anthropoid species to an evolutionary model suggested that the marmoset evolved from a gyrencephalic ancestor. Our results suggest that a high relative abundance of bRG cells may be necessary, but is not sufficient, for gyrencephaly and that the marmoset's lissencephaly evolved secondarily by changing progenitor parameters other than progenitor type.

FAM161A, associated with retinitis pigmentosa, is a component of the cilia-basal body complex and interacts with proteins involved in ciliopathies.

Retinitis pigmentosa (RP) is a retinal degenerative disease characterized by the progressive loss of photoreceptors. We have previously demonstrated that RP can be caused by recessive mutations in the human FAM161A gene, encoding a protein with unknown function that contains a conserved region shared only with a distant paralog, FAM161B. In this study, we show that FAM161A localizes at the base of the photoreceptor connecting cilium in human, mouse and rat. Furthermore, it is also present at the ciliary basal body in ciliated mammalian cells, both in native conditions and upon the expression of recombinant tagged proteins. Yeast two-hybrid analysis of binary interactions between FAM161A and an array of ciliary and ciliopathy-associated proteins reveals direct interaction with lebercilin, CEP290, OFD1 and SDCCAG8, all involved in hereditary retinal degeneration. These interactions are mediated by the C-terminal moiety of FAM161A, as demonstrated by pull-down experiments in cultured cell lines and in bovine retinal extracts. As other ciliary proteins, FAM161A can also interact with the microtubules and organize itself into microtubule-dependent intracellular networks. Moreover, small interfering RNA-mediated depletion of FAM161A transcripts in cultured cells causes the reduction in assembled primary cilia. Taken together, these data indicate that FAM161A-associated RP can be considered as a novel retinal ciliopathy and that its molecular pathogenesis may be related to other ciliopathies.

Chloroplastic phosphoadenosine phosphosulfate metabolism regulates basal levels of the prohormone jasmonic acid in Arabidopsis leaves.

Levels of the enzymes that produce wound response mediators have to be controlled tightly in unwounded tissues. The Arabidopsis (Arabidopsis thaliana) fatty acid oxygenation up-regulated8 (fou8) mutant catalyzes high rates of alpha -linolenic acid oxygenation and has higher than wild-type levels of the alpha -linolenic acid-derived wound response mediator jasmonic acid (JA) in undamaged leaves. fou8 produces a null allele in the gene SAL1 (also known as FIERY1 or FRY1). Overexpression of the wild-type gene product had the opposite effect of the null allele, suggesting a regulatory role of SAL1 acting in JA synthesis. The biochemical phenotypes in fou8 were complemented when the yeast (Saccharomyces cerevisiae) sulfur metabolism 3'(2'), 5'-bisphosphate nucleotidase MET22 was targeted to chloroplasts in fou8. The data are consistent with a role of SAL1 in the chloroplast-localized dephosphorylation of 3'-phospho-5'-adenosine phosphosulfate to 5'-adenosine phosphosulfate or in a closely related reaction (e.g. 3',5'-bisphosphate dephosphorylation). Furthermore, the fou8 phenotype was genetically suppressed in a triple mutant (fou8 apk1 apk2) affecting chloroplastic 3'-phospho-5'-adenosine phosphosulfate synthesis. These results show that a nucleotide component of the sulfur futile cycle regulates early steps of JA production and basal JA levels.

Role of the GNOM gene in Arabidopsis apical-basal patterning--From mutant phenotype to cellular mechanism of protein action.

How the apical-basal axis of polarity is established in embryogenesis is still a mystery in plant development. This axis appeared specifically compromised by mutations in the Arabidopsis GNOM gene. Surprisingly, GNOM encodes an ARF guanine-nucleotide exchange factor (ARF-GEF) that regulates the formation of vesicles in membrane trafficking. In-depth functional analysis of GNOM and its closest relative, GNOM-LIKE 1 (GNL1), has provided a mechanistic explanation for the development-specific role of a seemingly mundane trafficking regulator. The current model proposes that GNOM is specifically involved in the endosomal recycling of the auxin-efflux carrier PIN1 to the basal plasma membrane in provascular cells, which in turn is required for the accumulation of the plant hormone auxin at the future root pole through polar auxin transport. Thus, the analysis of GNOM highlights the importance of cell-biological processes for a mechanistic understanding of development.

Individual-tree basal area growth models for scots pine, pubescent birch and Norway spruce on drained peatlands in Finland

Summary

Comparing Basal Area Diameter Distributions Estimated by Tree Species and for the Entire Stock in a Mixed Stand

Summary

Seasonal changes in 24-h and basal energy expenditures in rural Gambian men as measured in a respiration chamber.

Adaptation of 24-h energy expenditure (24-h EE) to seasonal variations in food availability was studied, by using a respiration chamber, in 18 rural Gambian men on three occasions: period 1--at the end of the rainy season, which is characterized by low food availability; period 2--during the nutritionally favorable dry season; and period 3--at the onset of the following rainy season. From periods 1 to 2 body weight increased by 2.8 +/- 0.4 kg, and a rise in 24-h EE was observed (from 8556 +/- 212 kJ/d to 9166 +/- 224 kJ/d), which was correlated to weight change (r = 0.73, P less than 0.001). During period 3, 24-h EE averaged 8740 +/- 194 kJ/d. Diet-induced thermogenesis increased significantly from periods 1 to 2 (5.9 +/- 0.5% to 8.2 +/- 0.8%) and subsequently decreased to 3.6 +/- 0.6% during period 3. In rural Gambian men, metabolic adaptations in response to seasonal changes in food availability are reflected by a decrease in body weight, mainly manifested by a loss of fat-free mass accompanied by a decreased 24-h EE and a lowered diet-induced thermogenesis.