B-Type and C-Type Natriuretic Peptides Modify Norepinephrine Uptake in Discrete Encephalic Nuclei of the Rat

SUMMARY 1. We previously demonstrated that atrial natriuretic factor and B- and C-type natriuretic peptides (ANF, BNP, and CNP, respectively) modified catecholamine metabolism by increasing the neuronal uptake and decreasing the neuronal release of norepinephrine in the rat hypothalamus. The aim of the present work was to study the effects of natriuretic peptides BNP and CNP on norepinephrine uptake as an index of the amine metabolism in discrete areas and nuclei of the central nervous system (CNS) of the rat.2. Experiments were carried out in vitro using the punchout technique in diverse areas and nuclei of rat CNS. Results showed that 100 nM BNP and 1 nM CNP increased norepinephrine (NE) uptake in all brain areas and nuclei studied.3. Present results permit us to conclude that BNP and CNP regulate NE metabolism independently of the encephalic area or nucleus involved. In fact, NE uptake increased in nuclei related to the regullation of cardivascular activity as well as nuclei associated with endocrine metabolism and hydrosaline homeostasis. These observations suggest that BNP and CNP may be involved in the regulation of these physiological processes in an indirect manner through modifications of noradrenergic neurotransmission. Present findings provide futher support to the hypothesis that CNP would be the main natriuretic peptide in brain. Furthermore, previous as well as present results support the role of the natriureic peptides as neuromodulators of noradrenergic transmission at the presynaptic level.     

Visuomotor transformations: early cortical mechanisms of reaching

Recent studies of visually guided reaching in monkeys support the hypothesis that the visuomotor transformations underlying arm movements to spatial targets involve a parallel mechanism that simultaneously engages functionally related frontal and parietal areas linked by reciprocal cortico-cortical connections. The neurons in these areas possess similar combinations of response properties. The multimodal combinatorial properties of these neurons and the gradient architecture of the parieto-frontal network emerge as a potential substrate to link the different sensory and motor signals that arise during reaching behavior into common hybrid reference frames. This convergent combinatorial process is evident at early stages of visual information processing in the occipito-parietal cortex, suggesting the existence of re-entrant motor influences on cortical areas once believed to have only visual functions.     

The use of forest inventory data for a National Protected Area Strategy in Guyana

Forest inventories are largely neglected in the debate of national parks selection in Guyana (and probably elsewhere). Because taxonomic data are often scant and biased towards are as of high collecting effort, large scale forest inventory data can be a useful tool adding to a knowledge database for forests. In this paper the use of forest inventories to select national parks in Guyana is assessed. With the data of a large scale inventory five forest regions could be distinguished and two were added on the base of existing other information. Forest composition in Guyana is largely determined by geology at a national level and soil type at regional level. Species diversity is higher in the south of Guyana, possibly due to higher disturbance and is also higher on the better soils. It is concluded that a selection of national parks in Guyana should include a sample of all seven regions, including as much soil variation as possible. Because of land use conflicts in central Guyana, this area is in need of quick attention of Guyana's policy makers.     

Distinct and overlapping binding sites for IKP104 and vinblastine on tubulin

IKP104 is one of a group of tubulin-binding drugs whose interaction with tubulin suggests that it may bind to the protein at or close to the region where vinblastine binds. By itself IKP104 is a potent enhancer of tubulin decay as evidenced by the fact that it induces the exposure of the sulfhydryl groups and hydrophobic areas on tubulin. In this respect, IKP104 differs from vinblastine and other drugs such as phomopsin A, dolastatin 10, rhizoxin, and maytansine which are competitive or noncompetitive inhibitors of vinblastine binding. In contrast, however, in the presence of colchicine, IKP104 behaves differently and strongly stabilizes tubulin, to an extent much greater than does colchicine alone. IKP104 appears to have two classes of binding site on tubulin, differing in affinity; the acceleration of decay appears to be mediated by the low-affinity site (Chaudhuriet al., 1998,J. Protein Chem., in press). We investigated the relationship of the binding of IKP104 and vinblastine. We found that the high-affinity site or sites of IKP104 overlap with or interact with the vinblastine-binding sites, but that the low-affinity site is distinctly different.     

广西姑婆山及邻近地区大型真菌物种多样性

姑婆山紧邻南岭生物多样性保护优先区，孕育了丰富的生物资源。为了解该区域大型真菌物种多样性，该文采用随机踏查法对广西姑婆山自治区级自然保护区(以下简称姑婆山)及邻近地区大型真菌资源进行调查采集，并结合形态学和分子生物学方法进行物种鉴定。结果表明：(1)共发现348种大型真菌，隶属于2门6纲17目69科175属，其中包含食用菌40种、药用菌42种、毒菌7种。(2)对该区的物种组成分析表明，优势科为蘑菇科(Agaricaceae)、牛肝菌科(Boletaceae)、粉褶蕈科(Entolomataceae)和锈革菌科(Hymenochaetaceae)等9科；优势属为鹅膏属(Amanita)、靴耳属(Crepidotus)、毛皮伞属(Crinipellis)和粉褶蕈属(Entoloma)等11属。(3)共发现2个中国特有属，即脆孔菌属(Fragiliporia)和臧氏牛肝菌属(Zangia);11个中国特有种，即厚集毛菌(Coltricia crassa)、魏氏集毛菌(C.weii)、丛生粉褶蕈(Entoloma caespitosum)、极细粉褶蕈(E.praegracile)、近薄囊粉褶蕈...     

Priority areas of intraspecific diversity: Larzac, a global hotspot for facultative paedomorphosis in amphibians

Although the designation of biodiversity hotspots is a valuable tool to improve conservation efforts, this is a concept primarily based on species diversity. In consequence, another component of biodiversity, adaptive variation, is often ignored in conservation and to my knowledge no attempt has been made to identify hotspots of remarkable intraspecific patterns. My aim was to focus on the process of facultative paedomorphosis (i.e. the retention of larval traits such as gills in adult variants), a rare developmental pathway. One hundred and seventy-four ponds were inventoried in Larzac (France) to determine the distribution and abundance of paedomorphic palmate newts Triturus helveticus (Amphibia, Caudata) and to compare these results with the current distribution of paedomorphs in this and other species. During this study, paedomorphic newts were found in 46 ponds, 32 of which were described here for the first time. Seventy-nine per cent of known paedomorphic populations of this species were found there, whereas this area covers only 0.5% of the distribution area of the species. This represents the highest known density of facultatively paedomorphic populations, all species being considered. Because these populations face a high threat of disappearance, Larzac should be designated as an intraspecific biodiversity hotspot in order to protect adaptive intraspecific variation. Future conservation-oriented work should focus not only on species distributions but also on phenotypically diverse but spatially localized variation.     

Different flowering phenology of alien invasive species in Spain: evidence for the use of an empty temporal niche?

Flowering phenology is an important and poorly understood plant trait that may possibly be related to the invasiveness potential of alien species. The present work evaluates whether flowering time of invasive alien species is a key trait to overcome the climatic filters operating in continental Mediterranean ecosystems of Spain (characterised by summer drought and low temperatures in winter). We conducted comparisons between the flowering phenology of the invasive species in their native range and in Spain, and between flowering phenology of 91 coexisting invasive–native species pairs. For the alien species, geographical change from the native to the invaded region did not result in shifts in the start and the length of the flowering period. Overall, climatic conditions in the native range of species selected for a flowering pattern is maintained after translocation of the species to another region. Flowering of tropical and temperate invasive alien species peaked in summer, which contrasts with the spring flowering of native and invasive alien species of Mediterranean climate origin. By exploiting this new temporal niche, these invasive alien species native to tropical and temperate regions benefit from reduced competition with natives for abiotic and biotic resources. We suggest that human-mediated actions have reduced the strength of the summer drought filter in particular microhabitats, permitting the invasion of many summer-flowering aliens.     

A preliminary account of patterns of endemism in Namibia's Sperrgebiet – the succulent karoo

Aim This study investigated spatial patterns of endemism in the flora of Namibia's succulent karoo in order to generate information for conservation planning. Location The study area, the Sperrgebiet, comprises the majority of Namibia's portion of the succulent karoo biome which is the south‐west corner of the country. This is an arid area that has been off limits to public access, farming and tourism for nearly a century due to restrictions imposed by the diamond industry. Methods Based on existing distribution records, areas of high concentrations of endemic plants were identified using numbers of endemics and weighted endemics according to area of occupancy. The resolution of the available data was quarter degree squares (15‐min intervals of latitude and longitude grids). Results At the scale of this study straight numbers of endemics generated similar results to the endemics weighted according to area of occupancy, which gives sparsely distributed species a higher weighting. Based on the current distribution records, 17.7% (184 species) of the Sperrgebiet's spermatophyte flora is endemic. The ‘hotspots of endemism’ comprised from north to south: Lüderitz‐Kowisberge, Klinghardt Mountains, Aurusberge‐Heioab, Witpütz, Skorpion and Obib‐Schakalsberge. Taking also areas into account that stand out because of their high proportion of local endemics, this adds Grillental and the central coastal area from Pomona to Baker's Bay to the areas of importance for plant endemism. Main conclusions The Sperrgebiet's endemic flora is special in taxonomic composition in that it does not present a subset of the total flora of this area, but shows a remarkably high representation of the families Mesembryanthemaceae and Liliaceae (sensu lato). Compared with other arid areas, the level of endemism in the Sperrgebiet is high, but not compared with the succulent karoo in general or other hotspots in the succulent karoo biome, such as the Richtersveld. The proportion of local endemics (13.5%) is high compared with some endemism hotspots in southern Africa. Hotspots of plant endemism provide an important tool to contribute to conservation planning studies. This study also highlighted the importance of centralized data bases without which these analyses would not have been possible. Further plant collecting is required to fill presently data‐deficient areas and studies at a finer spatial resolution taking habitat requirements into account are needed to elucidate some of the factors contributing to plant endemism in this area.     

Grazing with Galloway cattle for floodplain restoration in the Syr Valley, Luxembourg

Three years after a river restoration scheme in the Syr Valley (Luxembourg) we investigated habitat development and habitat use of Galloway cattle deployed in a low-intensity grazing system on a permanent floodplain pasture. Habitats were delimited with a mobile GPS/GIS mapping system and their spatial development was assessed over three consecutive years. During these three years, the patches of the six habitats decreased to 40% of mean initial size, and a rapid net area expansion of wetland habitats (large sedge swamps: +100%, marsh and tall forb grasslands: +43%) was observed. The behavioural patterns and grazing preferences of the cattle were observed directly during the vegetation period in June, August and November. These observations were complemented by a transect analysis of cattle impact indicators in June and November. The cattle grazed the different habitats very selectively, as they preferred the mesophilic, and ruderal grasslands 1.6, and 5.6 times more than expected respectively. During the growing season, the grazing niche breadth declined (3.92 in June to 2.68 in November), and less preferred forage habitats like large sedge swamps were grazed primarily in the autumn. We used bite and step rates to investigate grazing intensity by habitat type. During summer, grazing intensity correlated with forage quality in the different habitat patches, whereas in autumn it was obviously influenced by the effort required to access the desired forage plants in a given habitat. The impact indicators revealed a matter transfer from riparian areas to the valley edge. Here, we give a first insight into habitat development and habitat use of Galloway cattle in a recently restored floodplain area and derive recommendations for the adaptive management of future projects.     

Survival of Colonizing Wolves in the Northern Rocky Mountains of the United States, 1982–2004

Abstract: After roughly a 60-year absence, wolves (Canis lupus) immigrated (1979) and were reintroduced (1995-1996) into the northern Rocky Mountains (NRM), USA, where wolves are protected under the Endangered Species Act. The wolf recovery goal is to restore an equitably distributed metapopulation of ≥30 breeding pairs and 300 wolves in Montana, Idaho, and Wyoming, while minimizing damage to livestock; ultimately, the objective is to establish state-managed conservation programs for wolf populations in NRM. Previously, wolves were eradicated from the NRM because of excessive human killing. We used Andersen–Gill hazard models to assess biological, habitat, and anthropogenic factors contributing to current wolf mortality risk and whether federal protection was adequate to provide acceptably low hazards. We radiocollared 711 wolves in Idaho, Montana, and Wyoming (e.g., NRM region of the United States) from 1982 to 2004 and recorded 363 mortalities. Overall, annual survival rate of wolves in the recovery areas was 0.750 (95% CI = 0.728-0.772), which is generally considered adequate for wolf population sustainability and thereby allowed the NRM wolf population to increase. Contrary to our prediction, wolf mortality risk was higher in the northwest Montana (NWMT) recovery area, likely due to less abundant public land being secure wolf habitat compared to other recovery areas. In contrast, lower hazards in the Greater Yellowstone Area (GYA) and central Idaho (CID) likely were due to larger core areas that offered stronger wolf protection. We also found that wolves collared for damage management purposes (targeted sample) had substantially lower survival than those collared for monitoring purposes (representative sample) because most mortality was due to human factors (e.g., illegal take, control). This difference in survival underscores the importance of human-caused mortality in this recovering NRM population. Other factors contributing to increased mortality risk were pup and yearling age class, or dispersing status, which was related to younger age cohorts. When we included habitat variables in our analysis, we found that wolves having abundant agricultural and private land as well as livestock in their territory had higher mortality risk. Wolf survival was higher in areas with increased wolf density, implying that secure core habitat, particularly in GYA and CID, is important for wolf protection. We failed to detect changes in wolf hazards according to either gender or season. Maintaining wolves in NWMT will require greater attention to human harvest, conflict resolution, and illegal mortality than in either CID or GYA; however, if human access increases in the future in either of the latter 2 areas hazards to wolves also may increase. Indeed, because overall suitable habitat is more fragmented and the NRM has higher human access than many places where wolves roam freely and are subject to harvest (e.g., Canada and AK), monitoring of wolf vital rates, along with concomitant conservation and management strategies directed at wolves, their habitat, and humans, will be important for ensuring long-term viability of wolves in the region.