bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Flowering in the Long-Day Grass Lolium temulentum by Gibberellins and the FLOWERING LOCUS T Gene
Authors: King Rod W. , Moritz Thomas , Evans Lloyd T. , Martin Jerome , Andersen Claus H. , Blundell Cheryl , Kardailsky Igor , Chandler Peter M. 
Published: April 2006

Abstract
Seasonal control of flowering often involves leaf sensing of daylength coupled to time measurement and generation and transport of florigenic signals to the shoot apex. We show that transmitted signals in the grass Lolium temulentum may include gibberellins (GAs) and the FLOWERING LOCUS T (FT) gene. Within 2 h of starting a florally inductive long day (LD), expression of a 20-oxidase GA biosynthetic gene increases in the leaf; its product, GA20, then increases 5.7-fold versus short day; its substrate, GA19, decreases equivalently; and a bioactive product, GA5, increases 4-fold. A link between flowering, LD, GAs, and GA biosynthesis is shown in three ways: (1) applied GA19 became florigenic on exposure to LD; (2) expression of LtGA20ox1, an important GA biosynthetic gene, increased in a florally effective LD involving incandescent lamps, but not with noninductive fluorescent lamps; and (3) paclobutrazol, an inhibitor of an early step of GA biosynthesis, blocked flowering, but only if applied before the LD. Expression studies of a 2-oxidase catabolic gene showed no changes favoring a GA increase. Thus, the early LD increase in leaf GA5 biosynthesis, coupled with subsequent doubling in GA5 content at the shoot apex, provides a substantial trail of evidence for GA5 as a LD florigen. LD signaling may also involve transport of FT mRNA or protein because expression of LtFT and LtCONSTANS increased rapidly, substantially (&gt;80-fold for FT), and independently of GA. However, because a LD from fluorescent lamps induced LtFT expression but not flowering, the nature of the light response of FT requires clarification.
Functional Characterization of Ice Plant SKD1, an AAA-Type ATPase Associated with the Endoplasmic Reticulum-Golgi Network, and Its Role in Adaptation to Salt Stress
Authors: Jou Yingtzy , Chiang Chih-Pin , Jauh Guang-Yuh , Yen Hungchen Emilie 
Published: April 2006

Abstract
A salt-induced gene mcSKD1 (suppressor of K+ transport growth defect) able to facilitate K+ uptake has previously been identified from the halophyte ice plant (Mesembryanthemum crystallinum). The sequence of mcSKD1 is homologous to vacuolar protein sorting 4, an ATPase associated with a variety of cellular activities-type ATPase that participates in the sorting of vacuolar proteins into multivesicular bodies in yeast (Saccharomyces cerevisiae). Recombinant mcSKD1 exhibited ATP hydrolytic activities in vitro with a half-maximal rate at an ATP concentration of 1.25 mm. Point mutations on active site residues abolished its ATPase activity. ADP is both a product and a strong inhibitor of the reaction. ADP-binding form of mcSDK1 greatly reduced its catalytic activity. The mcSKD1 protein accumulated ubiquitously in both vegetative and reproductive parts of plants. Highest accumulation was observed in cells actively engaging in the secretory processes, such as bladder cells of leaf epidermis. Membrane fractionation and double-labeling immunofluorescence showed the predominant localization of mcSKD1 in the endoplasmic reticulum-Golgi network. Immunoelectron microscopy identified the formation of mcSKD1 proteins into small aggregates in the cytosol and associated with membrane continuum within the endomembrane compartments. These results indicated that this ATPase participates in the endoplasmic reticulum-Golgi mediated protein sorting machinery for both housekeeping function and compartmentalization of excess Na+ under high salinity.
Existence of a no effect level for MeIQx hepatocarcinogenicity on a background of thioacetamide‐induced liver damage in rats
Authors: Kang Jin Seok , Wanibuchi Hideki , Morimura Keiichirou , Totsuka Yukari , Yoshimura Isao , Fukushima Shoji 
Published: March 2006

As exposure to heterocyclic amines might increase the risk of liver cancer, we investigated the carcinogenic potential of MeIQx under conditions of liver damage caused by TAA. Male, 6‐week‐old F344 rats (n = 280) were divided into 14 groups; groups 1–7 received TAA (0.03% in drinking water) and groups 8–14 received water for the first 12 weeks. Thereafter, the animals received MeIQx at doses from 0, 0.001, 0.01, 0.1, 1, 10 to 100 p.p.m. (groups 1–7 and 8–14, respectively) in pellet basal diet for 16 weeks. All survivors were killed at week 28 for assessment of numbers and areas of GST‐P positive foci, considered to be pre‐neoplastic lesions of the liver. Values were increased significantly in all the groups receiving TAA→MeIQx compared to MeIQx alone (P < 0.01). Numbers of GST‐P positive foci were significantly increased in groups 7 and 14 (treated with 100 p.p.m. MeIQx) as compared to 0 p.p.m.‐MeIQx (groups 1 and 8) (P < 0.01), along with areas in group 14 compared to group 8 (P < 0.01). However, with the maximum likelihood method, the data for numbers of GST‐P positive foci (groups 1–7 and groups 8–14) fitted the hockey stick regression model, representing no differences from groups 1–5 and from groups 8–13, despite a linear dose‐dependent increase of MeIQx‐DNA adducts from 0.1 to 100 p.p.m. We conclude that there is a no effect level for MeIQx hepatocarcinogenicity, even on a background of TAA‐induced liver damage. (Cancer Sci 2006; 97)
Plant harvest impacts and sustainability in Bwindi Impenetrable National Park, S.W. Uganda
Authors: Bitariho Robert , McNeilage Alastair , Babaasa Dennis , Barigyira Robert 
Published: March 2006

AbstractSustainable utilization of forest resources has been widely adopted as a conservation strategy, but that sustainability has rarely been empirically tested. Plant resource extraction from Bwindi Impenetrable National Park (BINP) by local communities has been legalized and controlled in areas called multiple use zones (MUZs). Through a series of systematic transects and plots, we determined harvest impacts of two mostly harvested medicinal plants of Rytigynia kigeziensis VERDC.l and Ocotea usambarensis Engl in BINP. The plots were placed in MUZs and non‐MUZs. Data on biomass production and population dynamics were collected from the plots. We also analysed forest society records for the past 3 years to determine annual plant resource offtakes from BINP. Bark production of the two plants in MUZs and non‐MUZs are not significantly different, suggesting an insignificant change in bark production because of bark harvest. Annual bark harvests of the two plants are between 0.26–1.64% of available bark stock. These are too low to cause any noticeable negative impacts and are sustainable. Annual bark harvest of R. kigeziensis and O. usambarensis should be increased from the original 1% to about 3% of available bark stock to allow more involvement of the marginalized poor people like Batwa in BINP.
Diversity of vascular plants on Ssese islands in Lake Victoria, central Uganda
Authors: Ssegawa Paul , Nkuutu David N. 
Published: March 2006

AbstractDiversity and distribution of trees [≥5 cm diameter at breast height (dbh)], shrubs and herbs was assessed in thirty 0.05‐ha (10 × 50 m) plots of a tropical high forest in the Ssese islands of Lake Victoria, central Uganda. The aim was to determine the floristic richness and composition of the forests. We recorded 179 species belonging to 70 families and 146 genera. Of these, nine families had five species or more. Rubiaceae was the richest with fourteen species followed by Euphorbiaceae (thirteen), Apocynaceae (ten) and Moraceae (nine). The majority of the families (35) were represented by one species each. Fifty‐eight herbaceous species, 39 lianas, ten shrubs and 72 species of trees were recorded. The commonest species recorded in the forest included: Uapaca guineensis Mull. Arg., Tabernaemontana pachysiphon Stapf., and Aframomum luteoalbum (K Schum.) K. Schum. Among the rare species encountered were Ficus densistipulata De Willd., Englerophytum oblanceolatum (S. Moore) Pennington, and Afromomum zambeziacum (Bak.) K. Schum. The present study has shown that the Ssese islands are floristically rich in species and compare well with other mainland forests. Species richness, rarity and uniqueness of habitats can be considered as approaches in the prioritization of conservation sites within the fragmented forests of Ssese islands.
Forb diversity and community similarity of kopjes in the Serengeti National Park, Tanzania
Authors: Poelchau Monica Frances , Mistry Shahroukh 
Published: March 2006

AbstractThe forb communities of kopjes (rock outcrops) in the Simba, Maasai and Loliondo areas of the Serengeti National Park were examined to determine differences in species composition from surrounding grassland communities, and among sites within kopje and grassland communities. Species diversity measures and multivariate ordination techniques were used to examine the community similarity and species turnover between sites. All measures of forb species diversity were higher on the kopje sites with the exception of one grassland site, and the community composition significantly differed between these two habitat types, with more species and families exclusive to the kopje habitat. Species turnover was very high in grassland habitats, with two of the three areas (Simba and Loliondo) exhibiting a complete change in species composition. Kopjes, on the other hand, had remarkably similar forb communities, suggesting that the populations of the species present on these rock outcrops form patch structures. The distinct flora and higher diversity of kopje forbs raise interesting questions regarding distribution, dispersal and patch dynamics.
Elevational variation in diversity and composition of land‐snail faunas in a Tanzanian forest
Authors: Tattersfield Peter , Seddon Mary B. , Ngereza Christine , Rowson Ben 
Published: March 2006

AbstractWe sampled terrestrial molluscs at fifteen elevations between 400 and 2000 m in Mwanihana Forest Reserve, Tanzania and recorded 84 taxa. Four diversity measures – species density (DP), species richness (D20) and observed (SO) and interpolated (SI) alpha diversity – were measured; beta diversity and abundance were also investigated. Mean elevational range was 470 m. DP, D20, alpha diversity and mollusc abundance increased with elevation, but alpha diversity peaked at 1695 m (SO) or 1500 m (SI) and declined at higher elevations. Maximum beta diversity was at 1000 m. Soil pH was negatively correlated with elevation and DP. Cluster analysis divided the sites into lowland (400–900 m) and highland (>1000 m) groups. Axis 1 of a canonical correspondence analysis was associated with altitude and suggested a faunal discontinuity at 1000 m. Variation within the highland (>1000 m) and lowland faunal sets was related to elevation and forest structure respectively. The findings indicate that mollusc diversity peaks at intermediate elevations. This may be related to the combined effects of low rainfall conditions at low elevations and increasing effects of soil leaching at high elevations, both of which may limit mollusc diversity and abundance. Diversity at intermediate altitudes may be further elevated because of faunal mixing of lowland and highland groups.
The role of salinity and sodicity in the dieback of Acacia xanthophloea in Ngorongoro Caldera, Tanzania
Authors: Mills A. J. 
Published: March 2006

AbstractDieback of Acacia xanthophloea (Benth.) has opened up the once densely forested Lerai area in Ngorongoro Caldera, Tanzania. Soil samples were taken from profiles in the Ngorongoro Conservation Area and Lake Manyara National Park at sites of dieback and at sites with healthy A. xanthophloea trees. Dieback sites had significantly greater electrical conductivity (EC), water‐soluble Na+, K+, Cl−, SO and sodium adsorption ratios (SAR) than healthy sites. The following mean values were recorded: EC (179 versus 70 mS m−1; P < 0.001, Student's t‐test, n = 8 and 10, respectively; 40–60 cm); Na+ (99 versus 30 mmolc kg−1, P < 0.001, n = 7 and 8 respectively); K+ (11 versus 3 mmolc kg−1, P < 0.05); Cl− (36 versus 7 mmolc kg−1, P < 0.01); SO (31 versus 5 mmolc kg−1, P < 0.01); and SAR (28 versus 8 mmol l−1/2, P < 0.01). Water‐soluble Na+, Cl− and SO concentrations in the Lerai profiles have probably resulted in toxicity and osmotic stress which contributed to dieback. Accumulation of salts may have occurred because of reduced flow of freshwater through Lerai and/or flow of water from Lake Magadi into Lerai. Forest recovery may be possible if salinity is reduced. Management strategies for reducing salinity have been implemented and included re‐establishing streams that flow through Lerai. Exclusion of elephants (Loxodonta africana) from Lerai is another management strategy presently under consideration.
Spatial and temporal patterns in Arvicanthis niloticus (Desmarest, 1822) as revealed by radio‐tracking
Authors: Hoffmann Anke , Eckhoff Katja , Klingel Hans 
Published: March 2006

AbstractArvicanthis niloticus was radio‐tracked in the grasslands of the Queen Elizabeth National Park in Uganda. Home range sizes calculated by Ranges V® using the Minimum Convex Polygon Method (at 95%) were on average 5.5 times larger in the bushland–grassland mosaic than those in the Abutilon guineense–Ocimum suave bushland. An inverse relation between home range size and population density was found. In both habitats the species was highly active during daylight hours but differed in activity patterns.
Will tree euphorbias (Euphorbia tetragona and Euphorbia triangularis) survive under the impact of black rhinoceros (Bicornis diceros minor) browsing in the Great Fish River Reserve, South Africa?
Authors: Heilmann Linda C. , de Jong Karen , Lent Peter C. , de Boer Willem F. 
Published: March 2006

AbstractThe impact of black rhinoceros (Bicornis diceros minor) on the tree euphorbias Euphorbia tetragona and Euphorbia triangularis was studied in the Great Fish River Reserve, South Africa. Black rhinoceros pushed over about 5–7% of the trees in a 2‐month period. There was a preference of rhinos for smaller trees, however this preference did not guarantee euphorbia survival in the larger size classes. This means that tree euphorbias could very well disappear from all areas accessible to rhinos. Rhino feeding choices were correlated with higher plant moisture content, higher nitrogen content, and a higher digestibility.
A policy tool for establishing a balance between wildlife habitat preservation and the use of natural resources by rural people in South Africa
Authors: Bouare Oumar 
Published: March 2006

AbstractIn this paper, a model is set up to determine the size of the wildlife population compatible with the extraction of the maximum output by rural people from natural resources. It is found that when the size of human population increases, to obtain the maximum output of food, the size of wildlife population decreases if the human population is growing faster than or at the same rate as that of the wildlife population; whereas the size of the wildlife population increases if the human population is growing slower than that of the wildlife. Furthermore, in the event that the increase in the size of the wildlife population is unable to reach the level compatible with the extraction of the maximum output of food, the improvement of the wildlife habitat and supplementing rural people's income with the proceeds of tourism are proposed as policies to maintain a balance between the preservation of the wildlife habitat and the use of natural resources by rural people.
C‐terminal nucleophosmin mutations are uncommon in chronic myeloid disorders
Authors: Caudill Jonathan S. C. , Sternberg Alexander J. , Li Chin‐Yang , Tefferi Ayalew , Lasho Terra L. , Steensma David P. 
Published: March 2006

SummaryC‐terminal somatic mutations in nucleophosmin (NPM), a nucleolar shuttling protein that binds p53 and p19Arf, were recently described in karyotypically normal acute myeloid leukaemia (AML). We analysed primary marrow samples from 150 patients with various chronic myeloid disorders for mutations in the NPM1 gene encoding NPM. NPM1 mutations (tetranucleotide duplication) were detected in three patients, all of whom had chronic myelomonocytic leukaemia (CMML) and a short (<1 year) survival, with rapid progression to overt AML. All other patients were NPM1‐wild type in the region analysed. In conclusion, C‐terminal NPM mutations are uncommon in chronic myeloid neoplasia, but if present may represent an evolving leukaemic clone.
Polyunsaturated fatty acids in zooplankton: variation due to taxonomy and trophic position
Authors: PERSSON JONAS , VREDE TOBIAS 
Published: March 2006

Summary1. Food quality has major effects on the transfer of energy and matter in food webs, and essential long‐chained polyunsaturated fatty acids (PUFAs) can affect the quality of phytoplankton as food. In a study of oligotrophic lakes in north‐western Sweden, we investigated the fatty acid composition of four planktonic cladocerans and two calanoid copepods, representing herbivorous and carnivorous species. We also collected seston samples.2. The proportions of long‐chain PUFAs in the organisms increased with their increasing trophic position. Thus, both their quality as food for other organisms, as well as their requirement for fatty acids (FAs), differed among taxa and depended on their trophic position.3. We found taxon‐specific differences in the FA composition of zooplankton that were not related to sestonic FA composition. This implies that the variation in zooplankton FA composition is constrained by phylogenetic origin, life history characteristics, or both.4. The cladoceran taxa contained 12–23% eicosapentaenoic acid (EPA) but only 0.9–2.1% docosahexaenoic acid (DHA) of the total FA content. In contrast, the calanoid copepods contained 7–11% EPA and 14–21% DHA. Thus, our results show that differences in the PUFA content among zooplankton species could have repercussions for both food web structure and function.
Prey switching inRhyacophila dorsalis(Trichoptera) alters with larval instar
Authors: ELLIOTT J.M. 
Published: March 2006

Summary1. Ontogenetic shifts in predator behaviour can affect the assessment of food‐web structure and the development of predator–prey models. Previous studies have shown that the diel activity pattern and functional response differed between larval instars of the carnivorous caddis,Rhyacophila dorsalis. The present study examines switching by larvae ofR. dorsalispresented with different proportions of two prey types; either small (length 2–4 mm) and large (5–8 mm)Chironomuslarvae for second, third, fourth and fifth instars ofR. dorsalis; orBaetis rhodani(9–12 mm) and largeChironomuslarvae for fourth and fifth instars. Experiments were performed in stream tanks with oneRhyacophilalarva per tank and 200 prey arranged in nine different combinations of the two prey types (20 : 180, 40 : 160, 60 : 140, 80 : 120, 100 : 100, 120 : 80, 140 : 60, 160 : 40 and 180 : 20). Prey were replaced as they were eaten. A model predicted the functional response in the absence of switching and provided a null hypothesis against which any tendency to switch could be tested.2. There was no prey switching in the second and third instars, with both instars always showing a preference for small over largeChironomuslarvae. Prey switching occurred in the fourth and fifth instars. As the relative abundance of one prey type increased in relation to the alternative, the proportion eaten of the former prey changed from less to more than expected from its availability, the relationship being described by an S‐shaped curve. In the experiments with small and largeChironomus, the two instars switched to large larvae when their percentage of the total available prey exceeded 29% and 37% for fourth and fifth instars, respectively. In the experiments withBaetisand largeChironomus, both instars switched toBaetislarvae when their percentage of the total available prey exceeded 36%.3. Non‐switching in second and third instars was related to their feeding strategies, both instars preferring smaller prey items. When the fourth and fifth instars foraged actively at night, they preferred larger over smallChironomuslarvae, but when they behaved as ambush predators at dusk, they captured the more activeBaetislarvae in preference to the more sedentary largeChironomuslarvae and only switched to the latter when they were >64% of the available prey.
Annual cycle and inter‐annual variability of gross primary production and ecosystem respiration in a floodprone river during a 15‐year period
Authors: UEHLINGER URS 
Published: March 2006

Summary1. Temporal variation in ecosystem metabolism over a 15‐year period (1986–2000) was evaluated in a seventh order channelised gravel bed river (mean annual discharge 48.7 m3 s−1) of the Swiss Plateau. The river is subject to frequent disturbance by bed‐moving spates. Daily integrals of gross primary production (GPP) and ecosystem respiration (ER) were calculated based on single‐station diel oxygen curves.2. Seasonal decomposition of the time series of monthly metabolism rates showed that approximately 50% of the variation of GPP and ER can be attributed to season. Annual GPP averaged 5.0 ± 0.6 g O2 m−2 day−1 and showed no long‐term trend.3. Ecosystem respiration, averaging 6.2 ± 1.4 g O2 m−2 day−1, declined from 8.8 to 4.1 g O2 m−2 day−1 during the 15‐year period. This significant trend paralleled a decline in nitrate and soluble reactive phosphorus concentrations, and the biochemical oxygen demand discharged by sewage treatment facilities upstream of the study reach. The ratio of GPP to ER (P/R) increased from 0.53 to about 1 as consequence of ER reduction.4. Bed moving spates reduced GPP by 49% and ER by 19%. Postspate recovery of GPP was rapid between spring and autumn and slow during winter. Recovery of ER lacked any seasonal pattern. Annual patterns of daily GPP and to a minor extent of daily ER can be described as a sequence of recovery periods frequently truncated by spates.5. The study showed that disturbance by frequent bed‐moving spates resulted in major stochastic variation in GPP and ER but annual patterns were still characterised by a distinct seasonal cycle. It also became evident that stream metabolism is a suitable method to assess effects of gradual changes in water quality.
High efficiency site‐specific genetic engineering of the mosquito genome
Authors: Nimmo D. D. , Alphey L. , Meredith J. M. , Eggleston P. 
Published: March 2006

AbstractCurrent techniques for the genetic engineering of insect genomes utilize transposable genetic elements, which are inefficient, have limited carrying capacity and give rise to position effects and insertional mutagenesis. As an alternative, we investigated two site‐specific integration mechanisms in the yellow fever mosquito, Aedes aegypti. One was a modified CRE/lox system from phage P1 and the other a viral integrase system from Streptomyces phage phi C31. The modified CRE/lox system consistently failed to produce stable germline transformants but the phi C31 system was highly successful, increasing integration efficiency by up to 7.9‐fold. The ability to efficiently target transgenes to specific chromosomal locations and the potential to integrate very large transgenes has broad applicability to research on many medically and economically important species.