bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understorey plant community structure in lower montane and subalpine forests, Grand Canyon National Park, USA
Authors: Laughlin Daniel C. , Bakker Jonathan D. , Fulé Peter Z. 
Published: October 2005

AbstractAim Our objectives were to compare understorey plant community structure among forest types, and to test hypotheses relating understorey community structure within lower montane and subalpine forests to fire history, forest structure, fuel loads and topography.Location Forests on the North Rim of Grand Canyon National Park, Arizona, USA.Methods We measured understorey (< 1.4 m) plant community structure in 0.1‐ha plots. We examined differences in univariate response variables among forest types, used permutationalmanovato assess compositional differences between forest types, and used indicator species analysis to identify species driving the differences between forest types. We then compiled sets of proposed models for predicting plant community structure, and used Akaike's information criterion (AICC) to determine the support for each model. Model averaging was used to make multi‐model inferences if no single model was supported.Results Within the lower montane zone, pine–oak forests had greater understorey plant cover, richness and diversity than pure stands of ponderosa pine (Pinus ponderosaP. & C. Lawson var.scopulorumEngelm.). Plant cover was negatively related to time since fire and to ponderosa pine basal area, and was highest on northern slopes and where Gambel oak (Quercus gambeliiNutt.) was present. Species richness was negatively related to time since fire and to ponderosa pine basal area, and was highest on southern slopes and where Gambel oak was present. Annual forb species richness was negatively related to time since fire. Community composition was related to time since fire, pine and oak basal area, and topography. Within subalpine forests, plant cover was negatively related to subalpine fir basal area and amounts of coarse woody debris (CWD), and positively related to Engelmann spruce basal area. Species richness was negatively related to subalpine fir basal area and amounts of CWD, was positively related to Engelmann spruce basal area, and was highest on southern slopes. Community composition was related to spruce, fir and aspen basal areas, amounts of CWD, and topography.Main conclusions In montane forests, low‐intensity surface fire is an important ecological process that maintains understorey communities within the range of natural variability and appears to promote landscape heterogeneity. The presence of Gambel oak was positively associated with high floristic diversity. Therefore management that encourages lightning‐initiated wildfires and Gambel oak production may promote floristic diversity. In subalpine forests, warm southern slopes and areas with low amounts of subalpine fir and CWD were positively associated with high floristic diversity. Therefore the reduction of CWD and forest densities through managed wildfire may promote floristic diversity, although fire use in subalpine forests is inherently more difficult due to intense fire behaviour in dense spruce–fir forests.
Deriving ecological relationships from geographical correlations between host and parasitic species: an example with orchid bees
Authors: Nemésio André , Silveira Fernando A. 
Published: October 2005

AbstractAim  To investigate biogeographical patterns of cleptoparasitic Exaerete bee species and their orchid bee hosts.Location  Neotropical region, from Central America to southern Brazil.Methods  Correlations between relative frequencies of cleptoparasitic Exaerete species and their host Eulaema species were employed to investigate the geographical association between such species pairs.Results  Our data support the current proposition that the Eulaema meriana/Eulaema flavescens complex is the main host for Exaerete frontalis. Contrary to current belief, however, Eulaema nigrita apparently is not the only and, in some regions, not the most important host for Exaerete smaragdina.Main conclusions  Current knowledge on cleptoparasite host associations among orchid bees is based on fortuitous observations, and in some instances generalizations from such observations are not corroborated by the frequencies and distributions of the bees involved. Our data suggest that cleptoparasitic pressure, rather than other features of the forest environment, may be responsible for the low abundance of E. nigrita in the Amazonian forests.
Endemic and Indo‐Pacific plankton in the Mediterranean Sea: a study based on dinoflagellate records
Authors: Gómez Fernando 
Published: October 2005

AbstractAim  To investigate biogeographical patterns based on published dinoflagellate records from the Mediterranean and Black Seas, and to provide a tentative list of endemic and Indo‐Pacific dinoflagellates in the Mediterranean Sea.Location  Mediterranean Sea, Black Sea.Methods  Checklists of dinoflagellates of the Mediterranean and Black Seas were compared with worldwide literature records. Only species reported in the Indo‐Pacific Ocean or exclusively known in the Mediterranean Sea were selected for biogeographical analysis.Results  Dinoflagellates in the Mediterranean Sea comprised c. 43% of the world marine species and c. 88% of the dinoflagellate genera. Species richness among the Mediterranean sub‐basins showed marked differences due to the less reliable records of unarmoured (athecate) and rare dinoflagellates. These differences disappeared when only the more easily identifiable taxa were considered. Of the 673 dinoflagellates cited in the Mediterranean, 87% were also reported in the Atlantic Ocean. Only 40 taxa (6% of the total) were considered to be potential Indo‐Pacific species. Most were reported from the Ligurian Sea (21), and only two species from the Levantine basin. The other 48 taxa (7% of total) were known exclusively from the Mediterranean Sea, mainly from the Ligurian Sea. Half of these taxa were reported by a single author.Main conclusions  Substantial dinoflagellates species richness can be attributed, in part, to the historical tradition of taxonomic studies in the Mediterranean Sea. The list of species of both Indo‐Pacific and exclusively Mediterranean species included taxa of dubious taxonomic validity or that were insufficiently known. The exclusion of these questionable taxa revealed the near absence of endemic dinoflagellates in the Mediterranean Sea compared with macroscopic organisms. This could be related to: (1) continuous replenishment of the plankton populations by the inflow of Atlantic water through the Strait of Gibraltar, (2) the possibility that species introduced during the Pliocenic flooding after the Messinian salinity crisis have not had enough time to diverge from their Atlantic ancestors, and/or (3) the reliance on traditional taxonomy based on morphological characters, which precludes the detection of cryptic speciation.
Deciphering patterns of transoceanic dispersal: the evolutionary origin and biogeography of coastal lizards (Cryptoblepharus) in the Western Indian Ocean region
Authors: Rocha Sara , Carretero Miguel A. , Vences Miguel , Glaw Frank , James Harris D. 
Published: October 2005

AbstractAim  Cryptoblepharus is a genus of small arboreal or rock‐dwelling scincid lizards, widespread through the Indo‐Pacific and Australian regions, with a disjunct outlier in the Malagasy region. The taxonomy within this genus is controversial, with different authors ranking the different forms (now some 36) at various levels, from different species to subspecies of a single species, Cryptoblepharus boutonii. We investigated the biogeography and genetic differentiation of the Cryptoblepharus from the Western Indian Ocean region, in order to understand their origin and history.Location  Western Indian Ocean region.Methods  We analysed sequences of mitochondrial DNA (partial 12s and 16s rRNA genes, 766 bp) from 48 specimens collected in Madagascar, Mauritius, the four Comoros islands and East Africa, and also in New Caledonia, representing the Australo‐Pacific unit of the distribution.Results  Pairwise sequence divergences of c. 3.1% were found between the New Caledonian forms and the ones from the Western Indian Ocean. Two clades were identified in Madagascar, probably corresponding to the recognized forms cognatus and voeltzkowi, and two clades were identified in the Comoro islands, where each island population formed a distinct haplotype clade. The East African samples form a monophyletic unit, with some variation existing between Pemba, Zanzibar and continental Tanzania populations. Individuals from Mauritius form a divergent group, more related to populations from Moheli and Grand Comore (Comoros islands) than to the others.Main conclusions  The level of divergence between the populations from the Western Indian Ocean and Australian regions and the geographic coherence of the variation within the Western Indian Ocean group are concordant with the hypothesis of a colonization of this region by a natural transoceanic dispersal (from Australia or Indonesia). The group then may have diversified in Madagascar, from where it separately colonized the East African coast, the Comoros islands (twice), and Mauritius. The genetic divergence found is congruent with the known morphological variation, but its degree is much lower than typically seen between distinct species of reptiles.
Vulnerability of Mediterranean Basin ecosystems to climate change and invasion by exotic plant species
Authors: Gritti E. S. , Smith B. , Sykes M. T. 
Published: October 2005

AbstractAim To assess at a broad scale the vulnerability of Mediterranean vegetation to alien plant invasion under different climatic and disturbance scenarios.Location We simulated the vegetation biogeography and dynamics on five of the main islands of the Mediterranean Basin: Mallorca, Corsica, Sardinia, Crete and Lesvos.Methods We used LPJ‐GUESS, a generalized ecosystem model based on dynamic processes describing establishment, competition, mortality and ecosystem biogeochemistry. We simulated the vegetation distribution and dynamics using a set of plant functional types (PFTs) based on bioclimatic and physiological parameters, which included tree and shrub PFTs defined especially for the Mediterranean. Additionally, two invasive PFTs, an invasive tree type and an invasive herb type, were defined and used to estimate the vulnerability to invasion of a range of different ecosystems. The model was used to simulate climate changes and associated changes in atmospheric [CO2] to 2050 according to twoSpecialReport on Emissions Scenariosclimate scenarios (A1Fi and B1) combined with mean disturbance intervals of 3 and 40 years.Results The simulations and scenarios showed that the effect of climate change alone is likely to be negligible in many of the simulated ecosystems, although not all. The simulated progression of an invasion was highly dependent on the initial ecosystem composition and local environmental conditions, with a particular contrast between drier and wetter parts of the Mediterranean, and between mountain and coastal areas. The rate of ecosystem disturbance was the main factor controlling susceptibility to invasion, strongly influencing vegetation development on the shorter time scale.Main conclusions Further invasion into Mediterranean island ecosystems is likely to be an increasing problem: our simulations predict that, in the longer term, almost all the ecosystems will be dominated by exotic plants irrespective of disturbance rates.
Apoptosis: a basic biological phenomenon with wide‐ranging implications in human disease
Authors: FADEEL B. , ORRENIUS S. 
Published: October 2005

Abstract.Apoptosis is a highly regulated process of cell deletion and plays a fundamental role in the maintenance of tissue homeostasis in the adult organism. Numerous studies in recent years have revealed that apoptosis is a constitutive suicide programme expressed in most, if not all cells, and can be triggered by a variety of extrinsic and intrinsic signals. Many human diseases can be attributed directly or indirectly to a derangement of apoptosis, resulting in either cell accumulation, in which cell eradication or cell turnover is impaired, or cell loss, in which the apoptotic programme is inadvertently triggered. In addition, defective macrophage engulfment and degradation of cell corpses may also contribute to a dysregulation of tissue homeostasis. An increased understanding of the signalling pathways that govern the execution of apoptosis and the subsequent clearance of dying cells may thus yield novel targets for therapeutic intervention in a wide range of human maladies.
Nonatopic allergen‐independent mast cell activation in parasitized eosinophilic athymic rats
Authors: STOTEN A. , HUNTLEY J. , MISTRY H. , HARPER S. , BUNDICK R. , BROWN A. , PRITCHARD D. I. 
Published: October 2005

SUMMARY It is possible to induce eosinophilia in congenitally athymic rats by infection with the parasite Ascaris suum. Athymic bronchial eosinophilia is associated with increased expression of IL‐5 and eotaxin mRNA, and with the presence of residual T cells and mast cells. Anamnestic mastocytosis is particularly pronounced and in this study we examine the relationship between mast cell degranulation and IgE production in athymic rats following infection. Incubation of peritoneal mast cells from athymic rats with anti‐IgE induced dose‐dependent degranulation, as measured by histamine release. However, the failure of mast cells from infected athymic rats to degranulate following incubation with all but one of the parasite antigens selected confirms the absence of a specific IgE response. In contrast, all agonists induced degranulation in euthymic rats. The only parasite‐derived factor to induce histamine release in all mast cells was Ascaris body fluid, which contains an element capable of inducing IgE‐independent degranulation. Furthermore, increased levels of rat mast cell protease II in athymic bronchoalveolar lavage fluid suggest degranulation of mast cells by IgE and allergen independent means in vivo. We believe that the development of eosinophilic lung inflammation in the absence of specific IgE makes this a prototype for investigating the immunological mechanisms underlying nonatopic asthma.
Modulation of murine cellular immune response and cytokine production by salivary gland lysate of three sand fly species
Authors: ROHOUŠOVÁ I. , VOLF P. , LIPOLDOVÁ M. 
Published: October 2005

SUMMARY Saliva of sand flies (
Diptera: Phlebotominae
) plays an important role in transmission of Leishmania parasites by modulating host immune response. However, because of the different protein compositions of saliva, the immunomodulatory effects may vary among sand fly species. We have therefore analysed and compared the immunomodulation effects of salivary gland lysate (SGL) of three different sand flies. Spleen cells from BALB/c mice were incubated with SGL of Phlebotomus papatasi, P. sergenti or Lutzomyia longipalpis. Concanavalin A‐stimulated lymphocyte proliferation was significantly suppressed with SGLs of all three sand fly species and all SGL doses tested. This result indicates that saliva from different sand fly species is able to suppress host proliferative response even to the potent mitogen. In parallel experiments, we analysed the effect of SGL on IFN‐γ, IL‐2, and IL‐4 production; in mitogen‐stimulated cells SGLs markedly inhibited IFN‐γ production in all intervals tested (reduced up to 31%) and to a lesser degree impaired production of the other two cytokines as well. Despite some species‐specific differences in the intensity of immunomodulatory effects, saliva of all sand fly species modulated cell proliferation as well as cytokine production in a similar way.
Potential for recombinant Babesia bovis antigens to protect against a highly virulent isolate
Authors: HOPE M. , RIDING G. , MENZIES M. , COLDITZ I. , REVERTER A. , WILLADSEN P. 
Published: October 2005

SUMMARY Two antigens from Babesia bovis,12D3 and 11C5, were expressed and purified as recombinant proteins in Escherichia coli and used to vaccinate groups of six Babesia‐susceptible cattle. These were subsequently challenged with a highly virulent strain of B. bovis. All cattle showed symptoms of disease and most required treatment. Cattle vaccination groups receiving either 12D3 or 11C5 or a combination of both, reduced parasitaemia by approximately fourfold and a number of individual animals appeared to control the parasite infection. Control of parasites correlated with high monocyte numbers late in infection. The results thus confirm the potential usefulness of both antigens but also demonstrate the limitations of current formulations.
Ribavirin up‐regulates IL‐12 p40 gene expression and restores IL‐12 levels in Leishmania‐treated PBMCs
Authors: CONTE E. , MODICA A. , CACOPARDO B. , MESSINA L. , NIGRO L. , MESSINA A. 
Published: October 2005

SUMMARY Ribavirin, a nucleoside analogue that interferes with viral mRNA synthesis and inhibits the replication of RNA and DNA viruses, has been recently proposed as an effective immune response modulator. In the present report, we studied the effect of ribavirin on IL‐12 p40 gene expression in peripheral blood mononuclear cells (PBMCs) of healthy subjects. We also studied ribavirin effects on PBMCs activated with lipopolysaccharide (LPS) and phytohaemagglutinin (PHA) and treated with Leishmania donovani antigens. We provide evidence that ribavirin was able to up‐regulate IL‐12 p40 gene expression and to restore levels of IL‐12 p40 gene expression and IL‐12 secretion in fully activated PBMCs that were strongly inhibited by L. donovani antigens. Because effective management of leishmanial disease is usually associated with a prevalent T‐helper 1 immune response with elevated production of IL‐12,our preliminary results may be of particular interest, provided that they will be confirmed by further in vitro and in vivo studies, when considering a possible use of ribavirin as adjuvant in severe leishmanial disease.
Kinetics of immunoglobulin G, M, A and IgG subclass responses in experimental intravaginal trichomoniasis: prominence of IgG1 response
Authors: YADAV M. , GUPTA I. , MALLA N. 
Published: October 2005

SUMMARY Trichomoniasis, the most common nonviral sexually transmitted disease, is caused by infection with the protist Trichomonas vaginalis. The clinical spectrum varies from an asymptomatic state to mild, moderate or severe symptoms. However, the exact factors leading to varied symptomatology have not been well elucidated. The mouse is a useful experimental model for intravaginal trichomoniasis, for understanding the role of local immune responses in the pathogenesis and varied symptomatology of this disease. The present study reports anti‐Trichomonas IgG, IgM, IgA and IgG subclass antibody responses on different post‐infection days (3rd, 7th, 14th, 21st and 28th) in serum and vaginal washes of mice infected intravaginally with T. vaginalis isolates from 15 symptomatic and 15 asymptomatic women. Successful intravaginal infection was established by inoculating T. vaginalis in BALB/c mice pre‐inoculated with Lactobacillus acidophilus and pretreated with oestradiol. A significant increase in parasite load was observed on the 14th post‐infection day (p.i.d.) in mice inoculated with T. vaginalis isolates from symptomatic women as compared to asymptomatic women (P < 0·001), followed by reduction until the 28th p.i.d. (P < 0·05). A significant increase in specific IgG (P < 0·001) and in particular IgG1 (P < 0·001) and IgM (P < 0·01) responses was observed on the 14th p.i.d. in serum and vaginal washes of mice infected with T. vaginalis isolates from symptomatic women as compared to asymptomatic women. Significant increases in specific IgG, IgM and IgG1 responses was observed on the 14th p.i.d. in serum samples as compared with vaginal washes of mice infected with T. vaginalis isolates from symptomatic and asymptomatic women (P < 0·01), whereas no significant difference was observed in IgA, IgG2a, IgG2b and IgG3 antibody responses. The study indicates that specific IgG, particularly IgG1 and IgM, may be playing a role in establishing symptomatic infection.
Introduction of the carrot HSP17.7 into potato (Solanum tuberosum L.) enhances cellular membrane stability and tuberization in vitro
Authors: AHN YEH‐JIN , ZIMMERMAN J. LYNN 
Published: October 2005

ABSTRACTWe have examined the ability of a carrot (Daucus carota L.) heat shock protein gene encoding HSP17.7 (DcHSP17.7) to confer enhanced heat tolerance to potato (Solanum tuberosum L.), a cool‐season crop. The DcHSP17.7 gene was fused to a 6XHistidine (His) tag to distinguish the engineered protein from endogenous potato proteins and was introduced into the potato cultivar ‘Désirée’ under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Western analysis showed that engineered DcHSP17.7 was constitutively, but not abundantly, expressed in transgenic potato lines before heat stress. Leaves from multiple regenerated potato lines that contain the transgene exhibited significantly improved cellular membrane stability at high temperatures, compared with wild‐type and vector control plants. Transgenic potato lines also exhibited enhanced tuberization in vitro: under a condition of constant heat stress, at 29 °C, nodal sections of the transgenic lines produced larger and heavier microtubers at higher rates, compared to the wild type and vector controls. The dry weight and percentages of microtubers that were longer than 5 mm were up to three times higher in the transgenic lines. Our results suggest that constitutive expression of carrot HSP17.7 can enhance thermotolerance in transgenic potato plants. To our knowledge, this is the first study that shows that the thermotolerance of potato can be enhanced through gene transfer.
Sanguinarine reductase, a key enzyme of benzophenanthridine detoxification
Authors: WEISS DAGMAR , BAUMERT ALFRED , VOGEL MATTHIAS , ROOS WERNER 
Published: October 2005

ABSTRACTCultured cells of Eschscholzia californica respond to a yeast glycoprotein elicitor by producing benzophenanthridine alkaloids, which are excreted into the cell wall and the outer medium. These compounds, preferentially sanguinarine, are efficient phytoalexins because of their ability to intercalate double‐stranded DNA (dsDNA), penetrate membranes and inhibit various enzymes containing SH‐groups. Externally added sanguinarine is rapidly taken up by intact cells and converted to dihydrosanguinarine, which is substituted intracellularly according to the biosynthetic route. A 29.5 kDa soluble enzyme that catalyses the reduction of sanguinarine and chelerythrine by either NADPH or NADH has been isolated and purified to homogeneity. Benzophenanthridines that accumulate in the outer medium, mainly 10‐OH‐chelerythrine, chelirubine and macarpine, are converted by the isolated enzyme and by intact cells at much slower rates than sanguinarine. The cellular capacity of uptake and conversion of sanguinarine largely surpasses the rate of alkaloid production. We conclude that the sanguinarine produced by intact cells, after excretion and binding to cell wall elements, is rapidly reabsorbed and reduced to the less toxic dihydrosanguinarine, which then undergoes further biosynthetic reactions. This recycling process would allow the presence of the toxic phytoalexin at the cellular surface without taking the risk of injuring the producing cell.