Estrogen receptor-alpha mediates estrogen protection from angiotensin II-induced hypertension in conscious female mice

It has been shown that the female sex hormones have a protective role in the development of angiotensin II (ANG II)-induced hypertension. The present study tested the hypotheses that 1) the estrogen receptor-alpha (ERalpha) is involved in the protective effects of estrogen against ANG II-induced hypertension and 2) central ERs are involved. Blood pressure (BP) was measured in female mice with the use of telemetry implants. ANG II (800 ng.kg(-1).min(-1)) was administered subcutaneously via an osmotic pump. Baseline BP in the intact, ovariectomized (OVX) wild-type (WT) and ERalpha knockout (ERalphaKO) mice was similar; however, the increase in BP induced by ANG II was greater in OVX WT (23.0 +/- 1.0 mmHg) and ERalphaKO mice (23.8 +/- 2.5 mmHg) than in intact WT mice (10.1 +/- 4.5 mmHg). In OVX WT mice, central infusion of 17beta-estradiol (E(2); 30 microg.kg(-1).day(-1)) attenuated the pressor effect of ANG II (7.0 +/- 0.4 mmHg), and this protective effect of E(2) was prevented by coadministration of ICI-182,780 (ICI; 1.5 microg.kg(-1).day(-1), 18.8 +/- 1.5 mmHg), a nonselective ER antagonist. Furthermore, central, but not peripheral, infusions of ICI augmented the pressor effects of ANG II in intact WT mice (17.8 +/- 4.2 mmHg). In contrast, the pressor effect of ANG II was unchanged in either central E(2)-treated OVX ERalphaKO mice (19.0 +/- 1.1 mmHg) or central ICI-treated intact ERalphaKO mice (19.6 +/- 1.6 mmHg). Lastly, ganglionic blockade on day 7 after ANG II infusions resulted in a greater reduction in BP in OVX WT, central ER antagonist-treated intact WT, central E(2) + ICI-treated OVX WT, ERalphaKO, and central E(2)- or ICI-treated ERalphaKO mice compared with that in intact WT mice given just ANG II. Together, these data indicate that ERalpha, especially central expression of the ER, mediates the protective effects of estrogen against ANG II-induced hypertension.     

Lethal recessive myelin toxicity of prion protein lacking its central domain

PrP(C)-deficient mice expressing prion protein variants with large amino-proximal deletions (termed PrP(DeltaF)) suffer from neurodegeneration, which is rescued by full-length PrP(C). We now report that expression of PrP(DeltaCD), a PrP variant lacking 40 central residues (94-134), induces a rapidly progressive, lethal phenotype with extensive central and peripheral myelin degeneration. This phenotype was rescued dose-dependently by coexpression of full-length PrP(C) or PrP(C) lacking all octarepeats. Expression of a PrP(C) variant lacking eight residues (114-121) was innocuous in the presence or absence of full-length PrP(C), yet enhanced the toxicity of PrP(DeltaCD) and diminished that of PrP(DeltaF). Therefore, deletion of the entire central domain generates a strong recessive-negative mutant of PrP(C), whereas removal of residues 114-121 creates a partial agonist with context-dependent action. These findings suggest that myelin integrity is maintained by a constitutively active neurotrophic protein complex involving PrP(C), whose effector domain encompasses residues 94-134.     

Enzyme Distribution Between the Cortex and the Infected Region of Soybean Nodules

Analysis of the distribution of enzymes of carbohydrate, carboxylicacid and nitrogen metabolism in nodule tissues prepared by protoplastisolation techniques has led to some confusion about their whereabouts.In this study nodule cortical and central (infected) tissuewas separated manually using a scalpel blade. Protein contents of whole nodules, central region and cortexwere found to be 19, 25 and 5-0 mg g^–1 fresh weight, respectively.Specific activities of glutamine synthetase (GS), phosphoenolpyruvatecarboxylase (PEPC), invertase (INV) and sucrose synthase (SS)were higher in the central region than in the cortex. The reversewas true for UDP glucose pyrophosphorylase (UDPGPP), phosphoglucomutase(PGM) and phosphoglucose isomerase (PGI). The central (infected) region represented a minimum of 65% ofthe nodule fresh weight. Calculations based on this estimateand on the activities per gram fresh weight indicate that thebulk of the potential enzyme activity is located in the centralregion. This was particularly so for SS, INV and GS where greaterthan 96% of the relevant activity was located in the centralregion. Even the enzymes which had greater specific activitiesin the cortex (UDPGPP, PGM and PGI) were, in fact, predominantlyfound in the central region (86, 81, and 85%, respectively).The conclusion from this data must be that most metabolism inthe nodule is likely to occur in the central region, althoughthis does not negate the importance of the cortex in carbonand nitrogen flux. Key words: Glycine max, soybean, nodules, cortex, infected region, enzymes     

Age trends in adiposity and central body fat distribution among adult white men resident in Peterborough,East Anglia,England

The pattern of fat distribution is related to a large number of variables of clinical importance. Many anthropometric indices have been derived which are surrogate measures of central fat distribution. However, systematic information on age variations in regional adiposity and central fat distribution is incomplete. The present study investigates the age variations in regional adiposity and five indices of central fat distribution among 262 adult White men resident in Peterborough, East Anglia, England. The five indices were studied: subscapular/triceps (STSR), abdomen/triceps (ATSR) and centripetal fat (CPFR) skinfold ratios, waist/hip ratio (WHR) and conicity index (CI). In general, the age patterns show progressive trend towards increasing central body fat distribution. The associations of age with all five central fat distribution indices were significant. These significant associations remained even after controlling for the body mass index (BMI). Therefore, this study provided evidence that there is a significant positive trend of increased central adiposity and fat distribution with increasing age in native English men. This trend is independent of BMI, which is a measure of overall adiposity. Such trends of enhanced fat accumulation in the central region of the body with age could have serious health implications especially with regard to chronic diseases like coronary heart disease (CHD), hypertension (HT) and non-insulin dependent diabetes mellitus (NIDDM). Future studies should also investigate whether the same phenomenon exists in other ethnic groups resident in Britain like South Asians who have very high prevalence of CHD and NIDDM.     

Central G-alpha subunit protein-mediated control of cardiovascular function, urine output, and vasopressin secretion in conscious Sprague-Dawley rats

The role(s) of central Galpha-proteins in the regulation of cardiovascular and renal function is unknown. We examined how inhibition/downregulation of central Galphai/Galphao, Galphaz or Galphaq proteins altered the characteristic cardiovascular (depressor), renal excretory (diuretic), and plasma AVP (inhibitory) responses to intracerebroventricular injection of nociceptin/orphanin FQ (N/OFQ) in rats. Before investigation, rats were pretreated intracerebroventricularly with saline vehicle (5 microl, 48 h, n=6), pertussis toxin (PTX; 48-h, 1 microg, n=6), or Galphaz, Galphaq, or scrambled oligodeoxynucleotide (ODN) (25 microg, 24 h, n=6 per group). On the study day, intracerebroventricular N/OFQ (5.5 nmol) or vehicle (5 microl) was injected into pretreated conscious rats. Mean arterial pressure (MAP) and heart rate (HR) were recorded, and urine was collected for 90 min. In vehicle or scrambled ODN groups, intracerebroventricular N/OFQ decreased MAP and HR and produced water diuresis (sensitive to UFP-101, N/OFQ receptor antagonist). The hypotension and bradycardia, but not diuresis, to N/OFQ were abolished in PTX-pretreated rats. In contrast, intracerebroventricular ODN pretreatment markedly blunted (Galphaz) or augmented (Galphaq) the diuresis to intracerebroventricular N/OFQ. In separate studies, the action of central N/OFQ to decrease plasma AVP levels in na?ve water-restricted rats was differentially altered by intracerebroventricular Galphaz ODN (blunted) and Galphaq ODN (augmented) pretreatment. These studies demonstrate central Galphai/Galphao activity mediates intracerebroventricular N/OFQ's cardiovascular depressor function. Alternatively, central Galphaz (inhibitory) and Galphaq (stimulatory) activity differentially modulates AVP release to control the pattern of diuresis to intracerebroventricular N/OFQ. These findings highlight the novel selective central Galpha-subunit protein-mediated control of cardiovascular vs. renal excretory function.     

Retinoids run rampant: multiple roles during spinal cord and motor neuron development

Learning how the incredible diversity of neurons in the vertebrate central nervous system (CNS) is generated is a central focus of developmental neuroscience. Three studies in the September 25, 2003, issue of Neuron bring us closer to this goal by revealing how the interplay between Fibroblast Growth Factor (FGF), retinoic acid (RA), and Sonic hedgehog (Shh) signaling regulate progression of spinal cord progenitor cells through various phases of development and specify particular types of spinal motor neurons (MNs).     

Examination of the structure, stability, and catalytic potential in the engineered phosphoryl carrier domain of pyruvate phosphate dikinase

Pyruvate phosphate dikinase (PPDK) is a multidomain protein that catalyzes the interconversion of ATP, pyruvate, and phosphate with AMP, phosphoenolpyruvate (PEP), and pyrophosphate using its central domain to transport phosphoryl groups between two distant active sites. In this study, the mechanism by which the central domain moves between the two catalytic sites located on the N-terminal and C-terminal domains was probed by expressing this domain as an independent protein and measuring its structure, stability, and ability to catalyze the ATP/phosphate partial reaction in conjunction with the engineered N-terminal domain protein (residues 1-340 of the native PPDK). The encoding gene was engineered to express the central domain as residues 381-512 of the native PPDK. The central domain was purified and shown to be soluble, monomeric (13,438 Da), and stable (deltaG = 4.3 kcal/mol for unfolding in buffer at pH 7.0, 25 degrees C) and to possess native structure, as determined by multidimensional heteronuclear NMR analysis. The main chain structure of the central domain in solution aligns closely with that of the X-ray structure of native PPDK (the root-mean-square deviation is 2.2 A). Single turnover reactions of [14C]ATP and phosphate, carried out in the presence of equal concentrations of central domain and the N-terminal domain protein, did not produce the expected products, in contrast to efficient product formation observed for the N-terminal central domain construct (residues 1-553 of the native PPDK). These results are interpreted as evidence that the central domain, although solvent-compatible, must be tethered by the flexible linkers to the N-terminal domain for the productive domain-domain docking required for efficient catalysis.     

Effects of central and systemic administration of leptin on neurotransmitter concentrations in specific areas of the hypothalamus

Leptin, a hormone produced by adipocytes, has been shown to affect a number of central functions, such as regulation of the hypothalamo-pituitary-adrenal axis, feeding, and body weight regulation. Because hypothalamic monoamines are intricately involved in the regulation of these functions, we hypothesized that leptin may produce its effects by altering the activity of these neurotransmitters. To test this hypothesis, male rats received peripheral (0, 100, or 500 microg ip), or central (0 or 5 microg icv) injections of leptin. The animals were killed 5 h later, and their brains were removed, frozen, and sectioned. Serum was collected to measure leptin and corticosterone by RIA. The paraventricular nucleus (PVN), arcuate nucleus (AN), ventromedial hypothalamus (VMH), dorsomedial dorsal nucleus (DMD), median eminence (ME), and medial preoptic area (MPA) were obtained using Palkovits' microdissection technique, and monoamine concentrations in these areas were determined using HPLC-EC. Intraperitoneal administration of leptin increased serum leptin concentrations in a dose-dependent manner (P < 0.05). Both intraperitoneal and intracerebroventricular administration of leptin decreased serum corticosterone significantly (P < 0.05). Norepinephrine (NE) concentration decreased significantly in the PVN, AN, and VMH after both intraperitoneal and intracerebroventricular administration of leptin (P < 0.05). NE concentrations decreased significantly in the DMN after intracerebroventricular administration of leptin (P < 0.05). Leptin treatment (both ip and icv) decreased dopamine concentrations significantly in the PVN. Serotonin (5-HT) concentration decreased significantly in the PVN after both intraperitoneal and intracerebroventricular injections of leptin and decreased in the VMH only with intracerebroventricular treatment of leptin. Leptin did not affect any of the monoamines in the ME and MPA. These results indicate that both central and systemic administration of leptin can affect hypothalamic monoamines in a region-specific manner, which, in turn, could mediate many of leptin's central and neuroendocrine effects.     

Section of tropical taxonomy: Seven new species and one new record of Polygala (Polygalaceae) from Somalia

The following new species are described: Polygala gypsophila (northern, central and southern Somalia, on gypsum), P. bariensis (northern Somalia, on limestone), P. hamarensis (coastal dunes near Mogadishu), P. argentea (central Somalia, on limestone near coast), P. gawenensis (central Somalia, on limestone), P. effusa (central Somalia and eastern Ethiopia, on sand), P. citrina (southern Somalia, on granitic outcrops). P. meonantha is reported for the first time from Somalia.     

Differential role of the paraventricular nucleus of the hypothalamus in modulating the sympathoexcitatory component of peripheral and central chemoreflexes

In the present study we investigated the involvement of the hypothalamic paraventricular nucleus (PVN) in the modulation of sympathoexcitatory reflex activated by peripheral and central chemoreceptors. We measured mean arterial blood pressure (MAP), heart rate (HR), renal sympathetic nerve activity (RSNA), and phrenic nerve activity (PNA) before and after blocking neurotransmission within the PVN by bilateral microinjection of 2% lidocaine (100 nl) during specific stimulation of peripheral chemoreceptors by potassium cyanide (KCN, 75 microg/kg iv, bolus dose) or stimulation of central chemoreceptors with hypercapnia (10% CO(2)). Typically stimulation of peripheral chemoreceptors evoked a reflex response characterized by an increase in MAP, RSNA, and PNA and a decrease in HR. Bilateral microinjection of 2% lidocaine into the PVN had no effect on basal sympathetic and cardiorespiratory variables; however, the RSNA and PNA responses evoked by peripheral chemoreceptor stimulation were attenuated (P < 0.05). Bilateral microinjection of bicuculline (50 pmol/50 nl, n = 5) into the PVN augmented the RSNA and PNA response to peripheral chemoreceptor stimulation (P < 0.05). Conversely, the GABA agonist muscimol (0.2 nmol/50 nl, n = 5) injected into the PVN attenuated these reflex responses (P < 0.05). Blocking neurotransmission within the PVN had no effect on the hypercapnia-induced central chemoreflex responses in carotid body denervated animals. These results suggest a selective role of the PVN in processing the sympathoexcitatory and ventilatory component of the peripheral, but not central, chemoreflex.     

Glutamate and GABA in the medial amygdala induce selective central sympathetic/parasympathetic cardiovascular responses

Glutamate and γ-aminobutyric acid (GABA) participate in central cardiovascular control, and are found in the rat posterodorsal medial amygdala (MePD), an area of the forebrain that modulates emotional/social behaviors. Here we tested whether these neurotransmitters in the MePD could change the basal activity, chemoreflex, and baroreflex cardiovascular responses in awake rats. Power spectral analysis and symbolic analysis were used to evaluate these responses. Microinjections of saline, glutamate (2 μg), or GABA (61 ng or 100 μg; n = 5-7 rats per group) did not affect basal parameters or chemoreflex responses. However, baroreflex responses showed marked changes. Glutamate increased power spectral and symbolic sympathetic indexes related to both cardiac and vascular modulations (P < 0.05). In turn, the displacement of the baroreflex half-maximal heart rate (HR) response was associated with a GABA (61 ng) mediated decrease in the upper plateau (P < 0.05). Administration of GABA (61 ng, but not 100 μg) also increased HR variability (P < 0.05), in association with parasympathetic activation. These data add novel evidence that the MePD can promote selective responses in the central regulation of the cardiovascular system, i.e., glutamate in the MePD evoked activation of a central sympathetic reflex adjustment, whereas GABA activated a central parasympathetic one.     

Mixed Connective Tissue Disease

A study was done that involved 46 patients with high-titer serum antibody to ribonucleoprotein (RNP). Common cutaneous manifestations included swollen hands or sclerodactyly (50 percent), cutaneous lupus erythematosus (48 percent), periungual telangiectasia (46 percent), alopecia (46 percent), dyspigmentation (28 percent), photosensitivity (28 percent) and vasculitis (22 percent). Frequent systemic characteristics included Raynaud phenomenon (93 percent), arthritis or arthralgia (91 percent), adenopathy (43 percent), vascular headaches (35 percent), serositis (35 percent), hoarseness (28 percent), myositis (26 percent), sicca syndrome (24 percent), renal disease (17 percent) and central nervous system disease (9 percent). Associated laboratory findings included antinuclear antibodies (100 percent), epidermal nuclear lgG deposition (91 percent), hypergammaglobulinemia (78 percent), esophageal dysmotility (61 percent), abnormal pulmonary function (59 percent), rheumatoid factor (57 percent), lupus erythematosus cells (37 percent), positive lupus band test (34 percent), hypocomplementemia (28 percent) and elevated anti-nDNA (21 percent).It appears that patients with high-titer anti-RNP (without appreciable amounts of “anti-Sm”) have a high prevalence of Raynaud phenomenon and a low prevalence of progressive renal insufficiency and severe central nervous system disease.     

The role of the cholinergic system in the central control of thermoregulation in rats

Systemic and central administration of methacholine (a synthetic choline derivative) both produced dose-dependent decreases in rectal temperature in rats at all the ambient temperatures studied. Both at room temperature (22 degrees C) and in the cold (8 degrees C), the hypothermia in response to methacholine application was brought about by both a decrease in metabolic heat production and an increase in cutaneous circulation. In the heat (29 degrees C), the hypothermia was due solely to an increase in respiratory evaporative heat loss. Furthermore, the methacholine-induced hypothermia was antagonized by central pretreatment of atropine (a selective blocker of cholinergic receptors), but not by the central administration of either 6-hydroxydopamine (a relative depletor of catecholaminergic nerve fibers) or 5,6-dihydroxytryptamine (predominately a serotonin depletor). The data indicate that activation of the cholinergic receptors within brain with methacholine decreases heat production and (or) increases heat loss which leads to hypothermia in rats.     

Neophobia and cortical and subcortical binding of the dopamine D2 receptor antagonist [3H]-raclopride

The potential role of dopamine system in response to novelty was analysed using the selective dopamine D2 receptor antagonist, raclopride, in behavioral and biochemical assays, in rats (the open field test, and specific binding of [3H]-raclopride, within different brain structures measured with autoradiography). It was found that raclopride at a low dose (50 microg/kg, IP) caused anxiolytic-like effect (increased the anti-thigmotactic index), whereas at a higher dose (500 microg/kg, IP) produced general inhibitory influence, and decreased the anti-thigmotactic index. Analysis of the behavioral and biochemical results of the experiment revealed a significant negative correlation between the ligand binding in the substantia nigra pars reticulata (SNR), and the number of entries into the central sector of the open field (r=-0.48, p<0.05), as well as the positive correlation between time spent in the central sector of the open field and [3H]-raclopride binding within nucleus accumbens septi (r=0.57, p<0.05). Factor analysis revealed a Factor 1 (eigenvalue=3.361) grouping parameters of central entries into the open field and [3H]-raclopride binding in the SNR (factor loadings are 0.814 and 0.703 respectively), indicating that both phenomena are under control of a similar central process. The above data are discussed in relation to the structure dependent dopamine D2 receptor mechanisms in a rat response to novelty.     

Ascorbic acid does not affect large elastic artery compliance or central blood pressure in young and older men

Large elastic artery compliance is reduced and arterial blood pressure (BP) is increased in the central (cardiothoracic) circulation with aging. Reactive oxygen species may tonically modulate central arterial compliance and BP in humans, and oxidative stress may contribute to adverse changes with aging. If so, antioxidant administration may have beneficial effects. Young (Y; 26 +/- 1 yr, mean +/- SE) and older (O; 63 +/- 2 yr, mean +/- SE) healthy men were studied at baseline and during acute (intravenous infusion; Y: n = 13, O: n = 12) and chronic (500 mg/day for 30 days; Y: n = 10, O: n = 10) administration of ascorbic acid (vitamin C). At baseline, peripheral (brachial artery) BP did not differ in the two groups, but carotid artery compliance was 43% lower (1.2 +/- 0.1 vs. 2.1 +/- 0.1 mm(2)/mmHg x 10(-1), P < 0.01) and central (carotid) BP (systolic: 116 +/- 5 vs. 101 +/- 3 mmHg, P < 0.05, and pulse pressure: 43 +/- 4 vs. 36 +/- 3 mmHg, P = 0.16), carotid augmentation index (AIx; 27.8 +/- 7.8 vs. -20.0 +/- 6.6%, P < 0.001), and aortic pulse wave velocity (PWV; 950 +/- 88 vs. 640 +/- 38 cm/s, P < 0.01) were higher in the older men. Plasma ascorbic acid concentrations did not differ at baseline (Y: 71 +/- 5 vs. O: 61 +/- 7 micromol/l, P = 0.23), increased (P < 0.001) to supraphysiological levels during infusion (Y: 1240 +/- 57 and O: 1,056 +/- 83 micromol/l), and were slightly elevated (P < 0.001 vs. baseline) with supplementation (Y: 96 +/- 5 micromol/l vs. O: 85 +/- 6). Neither ascorbic acid infusion nor supplementation affected peripheral BP, heart rate, carotid artery compliance, central BP, carotid AIx, or aortic PWV (all P > 0.26). These results indicate that the adverse changes in large elastic artery compliance and central BP with aging in healthy men are not 1). mediated by ascorbic acid-sensitive oxidative stress (infusion experiments) and 2). affected by short-term, moderate daily ascorbic acid (vitamin C) supplementation.     

A direct comparison of local-global integration in autism and other developmental disorders: implications for the central coherence hypothesis

The weak central coherence hypothesis represents one of the current explanatory models in Autism Spectrum Disorders (ASD). Several experimental paradigms based on hierarchical figures have been used to test this controversial account. We addressed this hypothesis by testing central coherence in ASD (n = 19 with intellectual disability and n = 20 without intellectual disability), Williams syndrome (WS, n = 18), matched controls with intellectual disability (n = 20) and chronological age-matched controls (n = 20). We predicted that central coherence should be most impaired in ASD for the weak central coherence account to hold true. An alternative account includes dorsal stream dysfunction which dominates in WS. Central coherence was first measured by requiring subjects to perform local/global preference judgments using hierarchical figures under 6 different experimental settings (memory and perception tasks with 3 distinct geometries with and without local/global manipulations). We replicated these experiments under 4 additional conditions (memory/perception*local/global) in which subjects reported the correct local or global configurations. Finally, we used a visuoconstructive task to measure local/global perceptual interference. WS participants were the most impaired in central coherence whereas ASD participants showed a pattern of coherence loss found in other studies only in four task conditions favoring local analysis but it tended to disappear when matching for intellectual disability. We conclude that abnormal central coherence does not provide a comprehensive explanation of ASD deficits and is more prominent in populations, namely WS, characterized by strongly impaired dorsal stream functioning and other phenotypic traits that contrast with the autistic phenotype. Taken together these findings suggest that other mechanisms such as dorsal stream deficits (largest in WS) may underlie impaired central coherence.     

Eight new species and a new record of Indigofera and Microcharis (Leguminosae-Indigofereae) from Somalia

The following new species are described: Indigofera bayensis (south-west Somalia, on sand or gravel in Acacia-Commiphora bushland), I. gypsacea (central and south-west Somalia, on gypsum), I. karkarensis (north-east Somalia, on limestone), I. lamellata (south-west Somalia, on and around granitic outcrops), I. lughensis (south-west Somalia, on gypsum), I. phymatodea (south-west Somalia, on granitic outcrops), I. scopiformis (central Somalia, on sand in Acacia-Commiphora bushland), and Microcharis nematophylla (central Somalia, on sand in Acacia-Commiphora bushland). Indigofera pseudointricata , previously known only from Socotra, is reported also from Somalia.     

Intracerebroventricular administration of urotensin II regulates food intake and sympathetic nerve activity in brown adipose tissue

To clarify the functional roles of urotensin II in regulating energy balance, we investigated the effects of a central infusion of urotensin II on food intake, uncoupling protein (UCP) 1 mRNA expression, temperature, and sympathetic nervous system activity in brown adipose tissue (BAT), a site that regulates energy expenditure in rodents. A bolus central infusion of urotensin II at a dose of 1 nmol/rat into the third cerebral ventricle decreased food intake (p<0.05). Additionally, urotensin II induced c-Fos-like-immunoreactivity (c-FLI) in the paraventricular nucleus (PVN) as compared with that in the control (phosphate buffered saline [PBS]-treated) group. Furthermore, urotensin II increased BAT UCP 1 mRNA expression (p<0.05). Finally, central infusion of urotensin II significantly increased BAT sympathetic nerve activity, which was accompanied by a significant elevation in BAT temperature (p<0.05) in rats. Taken together, central infusion of urotensin II regulates food intake and BAT sympathetic nerve activity in rats.     

The effect of biogeographic and phylogeographic barriers on gene flow in the brown smoothhound shark,Mustelus henlei,in the northeastern Pacific

We assessed the effects of the prominent biogeographic (Point Conception and the Peninsula of Baja California) and phylogeographic barriers (Los Angeles Region) of the northeastern Pacific on the population connectivity of the brown smoothhound shark, Mustelus henlei (Triakidae). Data from the mitochondrial control region and six nuclear microsatellite loci revealed significant population structure among three populations: northern (San Francisco), central (Santa Barbara, Santa Catalina, Punta Lobos, and San Felipe), and southern (Costa Rica). Patterns of long‐term and contemporary migration were incongruent, with long‐term migration being asymmetric and occurring in a north to south direction and a lack of significant contemporary migration observed between localities with the exception of Punta Lobos that contributed migrants to all localities within the central population. Our findings indicate that Point Conception may be restricting gene flow between the northern and central populations whereas barriers to gene flow within the central population would seem to be ineffective; additionally, a contemporary expansion of tropical M. henlei into subtropical and temperate waters may have been observed.     

Specific epithets of the flowering plants of central French Guiana

The epithets of the flowering plants of central French Guiana are classified into derivation categories. Specific epithets of the flowering plants of central French Guiana refer mostly to shapes (274 species), persons (252), places (212), appearance (146), and size (140). These categories account for 55% of names given to the plants of this flora. The most prolific publishers of names for the flora of central French Guiana are Aublet and Linnaeus, who were respectively the authors of 177 and 110 of the names of species (15% of the total) found in the flora of central French Guiana. Although many of the species names, such as those relating to place and person, are easy to categorize, many others are open to different interpretations. Specific epithets with different orthographies derived from Guiana or Guyana are discussed. In addition, problems in the use of diacritical marks and inconsistencies with spacing between the abbreviations of given names and surnames of authors of plant names are noted.