bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in forest fragment sizes and primate population trends along the River Tana floodplain, Kenya
Authors: Wahungu G. M. , Muoria P. K. , Moinde N. N. , Oguge N. O. , Kirathe J. N. 
Published: May 2005

AbstractThe Tana River forest patches significantly decreased in total area by 1875 ha (34.5%), from 5439 to 3564 ha between 1979 and 2000. The area covered by forests outside the Tana River Primate National Reserve declined by 1246 ha (38%) from 3283 to 2037 ha. This loss was higher than that inside the reserve, where total forest area reduced by 629 ha (29%) from 2156 to 1527 ha. The numbers of Tana River red colobus (Procolobus rufomitratus) and Tana crested mangabey (Cercocebus galeritus galeritus) groups were significantly correlated with forest sizes suggesting that both red colobus and crested mangabeys are likely to be affected by forest loss and fragmentation. However, comparison of the 1974/75 and 2001 census data did not reveal any significant change in the number of groups of either the red colobus or crested mangabey. The two endangered primates may have developed strategies to cope with a shrinking habitat.
Vigilance and group size in impala (Aepyceros melampus Lichtenstein): a study in Nairobi National Park, Kenya
Authors: Shorrocks Bryan , Cokayne Aimee 
Published: May 2005

AbstractOne of the advantages of living in groups is that individuals may need to be less vigilant, allowing them more time for other important activities, such as foraging. This relationship between group size and per cent time spent being vigilant was investigated by observing impala in Nairobi National Park, Kenya. Three types of individual were observed: females, territorial males and bachelor males. Only females showed the predicted negative relationship between per cent vigilance and herd size. Both types of male showed no significant change of vigilance with increasing group size. There was no difference in levels of vigilance in open or closed habitats and no difference in vigilance between herds ‘alone’ and herds with other species that might have provided ‘extra eyes’.
Abundance and dispersion of some chimpanzee‐dispersed fruiting plants at Mahale, Tanzania
Authors: Wakibara James V. 
Published: May 2005

AbstractAbundance and dispersion of five fruiting plant species the seeds of which are commonly dispersed by chimpanzees were investigated at Mahale Mountains National Park, Tanzania from August 2000 to February 2001. All plant individuals encountered within twenty‐three 50 × 50 m plots were counted and allocated to demographic stages. Plots were allocated proportionally to the main vegetation types in the chimpanzee range. Density and the demographic stages of individuals within 50 m radii of 10 adult conspecifics for four of the five sample species were also investigated. Overall, densities of individuals varied greatly by species and growth stages within the chimpanzee ranging space. Dispersion of the five plant species tested, irrespective of growth stages, showed a clumped pattern. However, Saba comorensis was the most evenly dispersed, irrespective of growth stage. Densities of juveniles and adults generally declined away from adult conspecifics, except for Syzygium guineense. These results are discussed in view of chimpanzees as potential seed dispersers. The hyper‐dispersion of S. comorensis appears to mirror the profound intensive and extensive dispersal of its seeds by chimpanzees, which are the main eaters of this fruit in the study area.
Seed weight patterns of Acacia tortilis from seven seed provenances across Botswana
Authors: Moleele N. M. , Reed M. S. , Motoma L. , Seabe O. 
Published: May 2005

AbstractLaboratory‐based seed storage systems have been developed as an alternative to in situ conservation for indigenous woody plant species. However, interactions between seed quality and environmental variables must be known for each species prior to seed collection, storage and sowing to ensure effective conservation. This study investigated Acacia tortilis seed weight/quality patterns across seven Botswana seed provenances in relation to: soil nutrient status, altitude; latitude; slope angle; % grass cover; height and density of other woody plants nearby. The higher rainfall and relatively eutrophic seed provenances of north‐western Botswana (Chobe, Okavango and Makgadikgadi) were associated with large A. tortilis species and seeds, as well as higher densities of woody plants. Spatial variation in seed weights of A. tortilis was principally a function of rainfall and soil organic carbon. Although more work is required to establish the relationship between seed weight and germination rates for A. tortilis, this research suggests that seed collection should focus on sites with high levels of rainfall and soil organic carbon.
Direct examination of soil for sporangia of Synchytrium endobioticum using chloroform, calcium chloride and zinc sulphate as extraction reagents
Authors: Van Leeuwen G. C. M. , Wander J. G. N. , Lamers J. , Meffert J. P. , Van Den Boogert P. H. J. F. , Baayen R. P. 
Published: May 2005

Fields infested with Synchytrium endobioticum can be descheduled when the soil is found free from sporangia of S. endobioticum. For direct examination, EPPO Standard PM 3/59 describes a soil extraction technique based on the use of a sieve shaker with six sieves. We compared recovery of sporangia between this (modified) method and an extraction method employed by the Dutch Plant Protection Service (PPS method). Recovery was determined using an inoculum dilution series: 125, 25, 5, 1, 0.2 or 0.04 sporangia per g soil. Extraction reagents used were chloroform and calcium chloride in the method described by EPPO, calcium chloride and zinc sulphate in the PPS method. At 125 sporangia per g soil, the mean density determined for the modified EPPO method was 228 sporangia per g soil when chloroform was used. Using calcium chloride, recovery percentage was higher for the modified EPPO method than for the PPS method (286, 136%, n.s. P < 0.05). The advantage of the modified EPPO method was the larger soil volume to be processed; its disadvantages were use of complex equipment and noxious reagents (chloroform). Both extraction methods showed high variation in recovery between samples, making accurate estimation of sporangial densities in soil awkward.
Production of a polyclonal antiserum against the coat protein of Cucurbit yellow stunting disorder crinivirus expressed in Escherichia coli
Authors: Cotillon A. C. , Desbiez C. , Bouyer S. , Wipf‐Scheibel C. , Gros C. , Delécolle B. , Lecoq H. 
Published: May 2005

Cucurbit yellow stunting disorder crinivirus infects cucurbit crops in the Middle East and the Mediterranean area (Egypt, Morocco, Spain, Portugal, South of France since 2001). Transmitted by Bemisia tabaci in a semipersistent manner, this virus provokes interveinal yellowing on older leaves of cucurbits, and is reported to cause significant economic losses in cucumber crops in Lebanon. Since it is very difficult to purify CYSDV, the main technique used for detection is RT‐PCR, which is not appropriate for routine tests. Therefore, the coat protein gene of a French isolate of CYSDV was amplified by RT‐PCR, cloned into bacterial expression vector pET16b allowing fusion of the protein with a N‐terminal 10xHis‐tag for easier purification, and transformed into Escherichia coli, strain BL21(DE3). The recombinant coat protein was produced at a high level, purified from cell lysates on a Ni‐NTA resin column, and used as an antigen to immunize a rabbit (three intradermal then six subcutaneous injections every 3 or 4 weeks). The resulting antiserum can be successfully used in DAS‐ELISA tests.
North American Brant: effects of changes in habitat and climate on population dynamics
Authors: Ward David H. , Reed Austin , Sedinger James S. , Black Jeffery M. , Derksen Dirk V. , Castelli Paul M. 
Published: May 2005

AbstractWe describe the importance of key habitats used by four nesting populations of nearctic brant (Branta bernicla) and discuss the potential relationship between changes in these habitats and population dynamics of brant. Nearctic brant, in contrast to most geese, rely on marine habitats and native intertidal plants during the non‐breeding season, particularly the seagrass, Zostera, and the macroalgae, Ulva. Atlantic and Eastern High Arctic brant have experienced the greatest degradation of their winter habitats (northeastern United States and Ireland, respectively) and have also shown the most plasticity in feeding behavior. Black and Western High Arctic brant of the Pacific Flyway are the most dependent on Zostera, and are undergoing a shift in winter distribution that is likely related to climate change and its associated effects on Zostera dynamics. Variation in breeding propensity of Black Brant associated with winter location and climate strongly suggests that food abundance on the wintering grounds directly affects reproductive performance in these geese. In summer, salt marshes, especially those containing Carex and Puccinellia, are key habitats for raising young, while lake shorelines with fine freshwater grasses and sedges are important for molting birds. Availability and abundance of salt marshes has a direct effect on growth and recruitment of goslings and ultimately, plays an important role in regulating size of local brant populations.
Patterns of rhizosphere carbon flux in sugar maple (Acer saccharum) and yellow birch (Betula allegheniensis) saplings
Authors: Phillips Richard P. , Fahey Timothy J. 
Published: May 2005

AbstractDespite its importance in the terrestrial C cycle rhizosphere carbon flux (RCF) has rarely been measured for intact root–soil systems. We measured RCF for 8‐year‐old saplings of sugar maple (Acer saccharum) and yellow birch (Betula allegheniensis) collected from the Hubbard Brook Experimental Forest (HBEF), NH and transplanted into pots with native soil horizons intact. Five saplings of each species were pulse labeled with 13CO2 at ambient CO2 concentrations for 4–6 h, and the 13C label was chased through rhizosphere and bulk soil pools in organic and mineral horizons for 7 days. We hypothesized yellow birch roots would supply more labile C to the rhizosphere than sugar maple roots based on the presumed greater C requirements of ectomycorrhizal roots. We observed appearance of the label in rhizosphere soil of both species within the first 24 h, and a striking difference between species in the timing of 13C release to soil. In sugar maple, peak concentration of the label appeared 1 day after labeling and declined over time whereas in birch the label increased in concentration over the 7‐day chase period. The sum of root and rhizomicrobial respiration in the pots was 19% and 26% of total soil respiration in sugar maple and yellow birch, respectively. Our estimate of the total amount of RCF released by roots was 6.9–7.1% of assimilated C in sugar maple and 11.2–13.0% of assimilated C in yellow birch. These fluxes extrapolate to 55–57 and 90–104 g C m−2 yr−1 from sugar maple and yellow birch roots, respectively. These results suggest RCF from both arbuscular mycorrhizal and ectomycorrhizal roots represents a substantial flux of C to soil in northern hardwood forests with important implications for soil microbial activity, nutrient availability and C storage.
Temporal pattern of plasma membrane calcium ATPase 2 expression in the spinal cord correlates with the course of clinical symptoms in two rodent models of autoimmune encephalomyelitis
Authors: Nicot Arnaud , Kurnellas Michael , Elkabes Stella 
Published: May 2005

AbstractAxonal/neuronal pathology is an important and early feature of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). However, the underlying molecular mechanisms remain elusive. We have previously reported that the levels of an important neuronal calcium pump, plasma membrane calcium ATPase 2 and synaptic proteins, synapsin IIa and syntaxin 1B are decreased in the rat spinal cord at onset of acute EAE. Whether the expression of these genes is restored during neurological recovery and affected in other EAE models is currently unknown. The present study was undertaken to address these issues by use of validated multiplex quantitative real‐time RT‐PCR with fluoro‐primers, western blot and immunocytochemistry. We report that plasma membrane calcium ATPase 2 (PMCA2) transcript and protein levels return to control values during recovery from acute disease in the Lewis rat, whereas they are reduced throughout the course of chronic, non‐remitting EAE in the C57Bl/6 mouse. These results indicate a close correlation between PMCA2 levels and disease course as defined by clinical scores reflecting motor deficits. Decrease in synapsin IIa expression also correlated with the onset and progression of neurological symptoms, whereas the pattern of syntaxin 1B mRNA and protein expression suggested post‐transcriptional regulation. The decrease in PMCA2 transcript and protein levels and the correlation between expression and disease course in two different EAE models further highlight the importance of this calcium pump in neuronal dysfunction during inflammation.
Role of the glycine site of the N‐methyl‐d‐aspartate receptor in synaptic plasticity induced by pairing
Authors: Krasteniakov N. V. , Martina M. , Bergeron R. 
Published: May 2005

AbstractIn the hippocampal CA1 region of the rat, activity‐dependent plasticity requires substantial postsynaptic depolarization and activation of the N‐methyl‐d‐aspartate glutamate receptor subtype (NMDAR). Exogenous and endogenous compounds selectively modulate NMDAR function by acting at the glycine coagonist site. Here we investigate the modulatory role of the glycine site in the induction of bidirectional synaptic plasticity. Plasticity was induced by pairing low‐frequency afferent pulses with different levels of postsynaptic depolarization in the absence and presence of glycine site compounds. We found strong dependence of glycine site agonist modulation on membrane voltage during induction. Thus, d‐serine and glycine were more effective in enhancing long‐term potentiation (LTP) during pairing of small depolarization (−60 or −50 mV) with subthreshold EPSCs than during pairing of stronger depolarization (−40 mV) with suprathreshold synaptic responses. The glycine site role in bidirectional synaptic plasticity was studied with the selective antagonist 7‐chlorokynurenic acid. Blockade of the glycine site during the pairing reversed the direction of plasticity from LTP towards long‐term depression. The magnitude of depression was dependent on antagonist concentration and the level of depolarization during the pairing. Thus, these experiments demonstrate the role of the glycine site in the induction of bidirectional synaptic plasticity.
Persistent alterations in neuropeptide Y release in the paraventricular nucleus of rats subjected to dietary manipulation during early life
Authors: Kozak R. , Richy S. , Beck B. 
Published: May 2005

AbstractThe aim of the present experiment was to determine the influence of nutritional manipulations during early life on feeding regulatory mechanisms. For this purpose, neuropeptide Y (NPY) release in the hypothalamic paraventricular nucleus was measured in male offspring born to dams fed either on a control (C) diet, on a high‐carbohydrate (HC) diet or on a high‐fat (HF) diet during gestation and lactation periods. In addition, we examined the development of dietary preferences in these rats. NPY release was measured in vivo through the push–pull technique after a stimulation with 2‐deoxy‐glucose (2DG), a blocker of carbohydrate metabolism. NPY release was significantly enhanced in the HC rats after 2DG (+89% vs. control and +54% vs. HF rats; P < 0.01). In a two‐bottle choice test, a clear preference for carbohydrate (62% vs. 38%; P < 0.01) was present as early as 30 days of age in control rats. The establishment of this preference in HC and HF rats was delayed by 2 and 3 months, respectively. Therefore, each type of dietary manipulation during early life has left a specific imprint in the offspring. The change in reactivity of the NPY system to glucopenia persisted in adulthood. When combined with the early changes in the dietary preferences, this can lead to adverse effects on body weight when abundant and palatable food is offered. These data support the hypothesis of an intrauterine and perinatal programming of the central regulatory mechanisms and reinforce the necessity of a preventive approach for the treatment of obesity and related metabolic disorders.
Forebrain patterns of c‐Fos and FosB induction during cancer‐associated anorexia–cachexia in rat
Authors: Konsman Jan Pieter , Blomqvist Anders 
Published: May 2005

AbstractForebrain structures are necessary for the initiation of food intake and its coupling to energy expenditure. The cancer‐related anorexia–cachexia syndrome is typified by a prolonged increase in metabolic rate resulting in body weight loss which, paradoxically, is accompanied by reduced food intake. The aim of the present work was to study the forebrain expression of Fos proteins as activation markers and thus to identify potential neurobiological mechanisms favouring catabolic processes or modulating food intake in rats suffering from cancer‐related anorexia–cachexia. Neurons in forebrain structures showing most pronounced induction of Fos proteins were further identified neurochemically. To provoke anorexia–cachexia, cultured Morris hepatoma 7777 cells were injected subcutaneously in Buffalo rats. This resulted in a slowly growing tumour inducing ≈ 7% body weight loss and a 20% reduction in food intake when the tumour represented 1–2% of body mass. Anorexia‐cachexia in these animals was found to be accompanied by Fos induction in several hypothalamic nuclei including the paraventricular and ventromedial hypothalamus, in the parastrial nucleus, the amygdala, the bed nucleus of the stria terminalis, ventral striatal structures and the piriform and somatosensory cortices. Neurochemical identification revealed that the vast majority of FosB‐positive neurons in the nucleus accumbens, ventral caudate–putamen and other ventral striatal structures contained prodynorphin or proenkephalin mRNA. These findings indicate that forebrain structures that are part of neuronal networks modulating catabolic pathways and food ingestion are activated during tumour‐associated anorexia–cachexia and may contribute to the lack of compensatory eating in response to weight loss characterizing this syndrome.
Intercollicular commissural projections modulate neuronal responses in the inferior colliculus
Authors: Malmierca Manuel S. , Hernández Olga , Rees Adrian 
Published: May 2005

AbstractThe right and left inferior colliculi (ICs) in the auditory midbrain are connected to one another by a bundle of fibres, the commissure of the IC. Previous studies show that this commissural projection connects corresponding frequency regions in the two sides and originates mainly from excitatory neurons, although some studies suggest a smaller number of GABAergic inhibitory neurons may also project via the commissure. Although the commissure of the IC is a major pathway connecting the most important nuclei of the auditory tectum, little is known about its functional significance. To investigate its role in auditory processing in the rat, we recorded sound‐evoked responses of single neurons in one IC while injecting kynurenic acid into a corresponding region of the opposite IC. This procedure enabled us to block reversibly excitation of commissural projections to the recorded IC. The changes in the neural responses when input from the opposite IC was blocked are consistent with the commissural projection exerting both an excitatory and an inhibitory influence. The inhibition could be accounted for by monosynaptic or disynaptic connections. The responses to both monaural and binaural stimulation were affected, and the effects were proportionately greater at near‐threshold sound levels. The results suggest that one function of the commissure of the IC may be to modulate the response gain of IC neurons to acoustic stimulation.
Orexin and MCH neurons express c‐Fos differently after sleep deprivation vs. recovery and bear different adrenergic receptors
Authors: Modirrousta Mandana , Mainville Lynda , Jones Barbara E. 
Published: May 2005

AbstractThough overlapping in distribution within the posterior hypothalamus, neurons containing orexin (Orx) and melanin concentrating hormone (MCH) may play different roles in the regulation of behavioural state. In the present study in rats, we tested whether they express c‐Fos differently after total sleep deprivation (SD) vs. sleep recovery (SR). Whereas c‐Fos expression was increased in Orx neurons after SD, it was increased in MCH neurons after SR. We reasoned that Orx and MCH neurons could be differently modulated by noradrenaline (NA) and accordingly bear different adrenergic receptors (ARs). Of all Orx neurons (estimated at ≈6700), substantial numbers were immunostained for the α1A‐AR, including cells expressing c‐Fos after SD. Yet, substantial numbers were also immunostained for the α2A‐AR, also including cells expressing c‐Fos after SD. Of all MCH neurons (estimated at ≈12 300), rare neurons were immunostained for the α1A‐AR, whereas significant numbers were immunostained for the α2A‐AR, including cells expressing c‐Fos after SR. We conclude that Orx neurons may act to sustain waking during sleep deprivation, whereas MCH neurons may act to promote sleep following sustained waking. Some Orx neurons would participate in the maintenance of waking during deprivation when excited by NA through α1‐ARs, whereas MCH neurons would participate in sleep recovery after deprivation when released from inhibition by NA through α2‐ARs. On the other hand, under certain conditions, Orx neurons may also be submitted to an inhibitory influence by NA through α2‐ARs.
Specificity of regions processing biological motion
Authors: Peuskens H. , Vanrie J. , Verfaillie K. , Orban G. A. 
Published: May 2005

AbstractUsing functional magnetic resonance imaging and point light displays portraying six different human actions, we were able to show that several visual cortical regions, including human MT/V5 complex, posterior inferior temporal gyrus and superior temporal sulcus, are differentially active in the subtraction comparing biological motion to scrambled motion. Comparison of biological motion to three‐dimensional rotation (of a human figure), articulated motion and translation suggests that human superior temporal sulcus activity reflects the action portrayed in the biological motion stimuli, whereas posterior inferior temporal gyrus responds to the figure and hMT/V5+ to the complex motion pattern present in biological motion stimuli. These results were confirmed with implied action stimuli.