bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationships between Solutes, Nutrients, and the Biofilm in Sediments of Floodplain Karstic and Alluvial Springs
Authors: Chafiq Mohamed , Gibert Janine 
Published: February 2007

AbstractTwo pairs of springs were surveyed in the floodplain of the Upper Rhône River. Each pair included a karstic (upstream) and an alluvial (downstream) spring in the same catchment. Various physical, chemical, and biological factors were measured in the water and the sediment. The study showed karstic and alluvial spring typology. In each pair, the karstic springs were characterized by higher alkalinity, whereas alluvial springs were fed both by karstic groundwater and Rhône River water with higher sulphate content.Organic matter dynamics and retention processes were different in each spring. The distribution and abundance of fine sediment played a prominent role in the storage of particulate organic carbon and the development of microbial biomass and activity. The hydrological cycle governed organic and inorganic nutrient fluxes, and was, with temperature, the main factor influencing microbial and macroinvertebrate dynamics. The high amount of organic matter in one alluvial spring was correlated with high microbial biomass and activity.
Substantial Increase of Chironomus Abundance Obtained in Field Experiment
Authors: Kajak Zdzisław , Dusoge Krzysztof 
Published: February 2007

AbstractMud (with or without Chironomus) taken from the bottom of a shallow (6 m) eutrophic reservoir, was maintained (about 3 weeks) in trays supported 30 cm and 70 cm above the bottom. At the end of the experiment it contained 7‐9 times more Chironomus plumosus individuals than did the mud at the bottom. Numbers of young (≤12 mm) larvae were up to 18 times higher, and youngest (≤6 mm) larvae (absent in the bottom at the end of the experiment) were abundant. Such patterns were more evident at the higher (70 cm) than the lower (30 cm) level. Numbers of the oldest (≥18 mm) larvae at the higher level were only 6 times higher (whilst more than 8 times at the lower level) than at the bottom, probably due to quicker development and emergence in higher trays. So the production of the population increased with the increasing distance from the bottom. In the tray at the bottom (which could protrude 1–2 cm above it) numbers were twice those outside it, and the youngest larvae occurred.There was a slight current at the research site. Nevertheless, short time oxygen deficits occurred periodically, and were probably the main cause of considerable reductions in Chironomus numbers at the bottom during the experiment.
Strategies of nitrogen cycling of Phragmites australis at two sites differing in nutrient availability
Authors: Kühl Harald , Woitke Peter , Kohl Johannes‐Günter 
Published: February 2007

AbstractBelow‐ground biomass and nitrogen content were determined at two genetically homogeneous Phragmites stands differing in morphology, in productivity, and in nutrient supply. Comparable ratios between above‐ground standing crop and rhizome biomass were found at both sites, whereas the root biomass/above standing crop ratio was significantly higher at the nutrient poor site. Investigations on the dynamics of nitrogen content revealed distinct differences in nitrogen translocation to the rhizomes between the investigated clones indicating two ecophysiological strategies in storage behaviour. These two strategies could be attached to the “assimilation type” and to the “translocation type”, respectively. A modified definition of both types is presented.
Zooplankton and bacteria contribution to phosphorus and nitrogen internal cycling in a tropical and eutrophic reservoir: Pampulha Lake, Brazil
Authors: Pinto‐Coelho Ricardo Motta , de Moura Raquel Teixera , Moreira Andrea 
Published: February 2007

AbstractNutrient regeneration and respiration rates of natural zooplankton from a tropical reservoir were experimentally measured. Excretion rates of ammonia (Ea), orthophosphate (Ep) and community respiration rates (R) were estimated considering the variations in the concentrations of ammonia, orthophosphate and dissolved oxygen between control and experimental units. The ranges obtained for these rates from the 2 h assays were Ea = 1.95–4.95 μg N‐NH4 · mg · DW−1 · h−1; Ep = 0.12–0.76 μg P‐PO4 mg DW−1 · h−1. Respiratory rates were quite constant (R = 0.01–0.02 mg O2 · mg DW−1 · h−1). The uptake of nutrients due to bacteria can affect the experimental determination of excretion rates of zooplankton. Orthophosphate release increased from 0.28 to 0.82 μg P‐PO4 · mg DW−1 · h−1 when bacterial activity was depleted by antibiotic addition in experimental vessels (Exp IV). This demonstrates that free living bacteria are able to consume promptly most phosphorus excreted by zooplankton. Ammonia excretion rates were lower in experimental units containing antibiotics. Lower excretion rates were also obtained with longer exposure times and higher biomass levels in the experimental units. Finally, this study also showed that zooplankton excretion can affect significantly turn over rates of total phosphorus in Pampulha Reservoir. In some periods, specially during the dry season when zooplankton biomass was very high, phosphorus release by zooplankton, during one single day, can be as high as 40% of the total phosphorus content in lake water (Turn over time = 2.5 days).
Extracellular, low‐affinity β‐N‐acetylglucosaminidases linked to the dynamics of diatoms and crustaceans in freshwater systems of different trophic degree
Authors: Vrba Jaroslav , Kofroňová‐Bobková Jitka , Pernthaler Jakob , Simek Karel , Macek Miroslav , Psenner Roland 
Published: February 2007

AbstractExtracellular hydrolysis of 4‐methylumbelliferyl β‐N‐acetylglucosaminide was measured in the oligomesotrophic Piburger See and the eutrophic Římov reservoir during spring and summer phytoplankton blooms, respectively. Total enzymatic activity (TEA) ranged between 0.2 and 19.1 nmol 1−1 h−1 in the reservoir and between 0.8 and 12.4 nmol 1−1 h−1 in the lake. High‐affinity (Km < 1 μmol 1−1) and lowaffinity (Km > 100 μmol 1−1) enzymes were kinetically identifiable in most samples from both localities. The low‐affinity enzyme activity (LEA) usually accounted for >60% (mean: 80%) of TEA. LEA and diatom biomass significantly correlated over time in the reservoir epilimnion (rs = 0.578) and in the lake metalimnion (rs = 0.862). As diatoms possess chitin and take up its monomer, N‐acetylglucosamine, two explanations of the observed relationships are suggested: extracellular β‐N‐acetylglucosaminidase activity partly originates either from ectoenzymes of chitinolytic bacteria attached to diatom cells or from ectoenzymes of diatoms, enabling them to take up N‐acetylglucosamine from ambient amino sugars instead of synthesizing it de novo. A significant positive correlation of LEA with crustacean abundance was found in the lake epilimnion (rs = 0.850), apparently reflecting the growing spring populations of frequently moulting juvenile crustaceans. A possible contribution of chitinolytic bacteria, accompanying the crustacean populations, to LEA is discussed.
Organic carbon dynamics in shelf edge sediments off the hebrides: A seasonal perspective
Authors: Mitchell Lynda , Harvey S. Martyn , Gage John D. , Fallick Anthony E. 
Published: February 2007

AbstractA benthic transect across the Hebridean Shelf Edge was sampled 9 times during 1995–96. Sediment samples from within the surface mixed layer were analysed for organic and inorganic carbon content, porosity, grain size and stable carbon isotope ratio. The organic carbon content is always <1% dry weight. Inorganic carbon content is 17–65% CaCO3. There is no significant seasonal variation in organic or inorganic carbon contents despite changing productivity in the water column. However, there is an inverse relationship between organic carbon content and median grain size. The isotopic composition shows strong seasonal variation which reflects the increase in phytoplankton detritus at the sediment‐water interface during spring/summer. The results suggest a small but rapid burial flux. However, the study area is not a significant depocentre for organic carbon.
Primary production of phytoplankton in Lake Valencia (Venezuela)
Authors: Infante Aida G. 
Published: February 2007

AbstractLake Valencia is heavily polluted by waste water of domestic, agricultural and industrial origin. The high organic load may have produced important changes in the limnological properties. Cyanobacteria dominated in numbers and biomass (over 90% throughout the year). Chlorophyll‐a content averaged 37.7 + 15 μg · 1−1. Maximum concentrations of 50–80 μg · 1−1 were found near the inflows affected by organically polluted affluents. There has been a 50% reduction in the euphotic zone in only 13 years. The maximum rate of gross photosynthesis per hour at light saturation was determined within the uppermost 1‐meter layer. The highest value was 16,290 mg O2 · m−3 · h−1. Lake Valencia is among the most productive lakes in the world, with areal net photosynthesis averaging 7.5 g C · m−2 · d−1.
Natural aquatic plant colonisation in a newly constructed Irish Canal
Authors: Caffrey Joseph , Monahan Catherine 
Published: February 2007

AbstractIn January 1989 a major breach in a section of the Grand Canal occurred. As a consequence, a 2.5 km long section required reconstruction. The channel was built up using peat material, lined with an impermeable membrane and overlayed with Puddle Clay. The section was rewatered in March 1990. For the next 30 months the course of natural aquatic plant colonisation was monitored. The first coloniser was the charophyte Tolypella glomerata, which appeared in September 1990. This occurred with low abundance until April 1991, when it disappeared. Between September 1991 and April 1992 charophytes, mainly T. glomerata and Chara vulgaris, proliferated. Their abundance diminished significantly during the summer of 1992. It was not until August 1991, 18 months after rewatering, that the first naturally colonising phanerogams were recorded. Principal among these was Myriophyllum verticillatum. In September of that year an aggressive coloniser in Irish canal and river habitats, Potamogeton pectinatus, was first observed. This became a permanent constituent of the flora and ultimately dominated the vegetation at the site. In total, 28 plant species were recorded from the newly constructed section. Nine of these species were either purposely or accidentally introduced during bankside stabilisation operations when live roots and rhizomes were planted along the exposed canal margins. By the end of the study period an abundant and diverse macroinvertebrate community had colonised the vegetation.
Phytoplankton community structure of a deep subalpine Italian Lake (Lake Orta, N. Italy) four years after the recovery from acidification by liming
Authors: Morabito Giuseppe , Curradi Michela 
Published: February 2007

AbstractThe phytoplankton succession in Lake Orta, heavy metals and ammonium polluted for decades and subjected to liming intervention in 1989–90, was studied during 1994. The existence of three main succession stages, with different structures of the community emerged. Chlorophyta are the most important taxonomic group in every season. The spring community was dominated by chlorophytes, Dinobryon sertularia and Kephyrion sp., the summer by Synedra sp. and Westella botryoides, the autumn by Rhizosolenia eriensis and W. botryoides, the winter by Synedra sp., R. eriensis and Synechococcus sp. The abundance of Chlorophyta, less important in other deep subalpine lakes, and the dominance of taxa able to thrive in polluted environments, could be related to the presence of trace metals in the sediments.
Neoperla (Plecoptera, Perlidae) Emerging from a Mountain Stream in Central Africa
Authors: Zwick Peter 
Published: February 2007

AbstractStudy of numerous adults was done for 5 species of Neoperla taken in an emergence trap on the stream Kalengo, Republic of Zaire, over 16 months (table 1). Taxonomic characters are evalutaed considering individual variation and variation between disjunct populations. The assumption by previous authors of only 1 variable species of Neoperla in Africa is refuted. Some bionomic data for the 2 common species in the material are presented. Biomass (dry weight) is 462.4 mg/m2/yr or 12% of total biomass of emerging insects (BÖTTGER 1975). Close agreement with figures reported for European streams (ILLIES 1971) may be accidental as biocoenotic structures are very different.
Abundance and Distribution of the Macrobenthic Infauna of the Gulf of Arauco, Chile
Authors: Carrasco Franklin D. , Gallardo Victor A. 
Published: February 2007

AbstractThe macrobenthic infauna of the Gulf of Arauco (Central Chile), was quantitatively sampled in April 1979. A total of 81 species were identified. The infauna was greatly dominated by polychaetes. The polychaete Paraprionospio pinnata and the amphipod Ampelisca araucana accounted for ca. 45 per cent of the total infauna in terms of numbers. Numerical classification produced four site‐groups and four species‐groups, mostly reflecting differences in character and depth of sediment. Several community characteristics differed for these assemblages. Biomass also was dominated by polychaetes, with Pectinaria chilensis, P. pinnata, Diopatra chiliensis and Glycera americana making up 45 per cent of the total. The high numbers of the fauna (mean = 15,021 ind m−2) and especially the high biomass figures (mean = 21.04 g AFDW m−2) reported are consistent with the high productivity of the area, subject to coastal upwelling processes.
Spatial Dynamics of Mesocyclops edax (S. A. FORBES), Tropocyclops prasinus mexicanus KIEFER, Diaptomus pallidus HERRICK, Ceriodaphnia lacustris (BIRGE), Bosmina longirostris (O. F. MÜLLER), Daphnia parvula (FORDYCE) and Nauplii in a Northeastern Ohio Pond
Authors: Teraguchi Mitsuo , Stucke Dennis E. , Noga Michael M. 
Published: February 2007

AbstractA hypothesis on spatial dynamics of pelagic crustacean plankters was tested with the copepods and cladocerans of Squire Pond, Ohio. There was an agreement between the expected and the observed pattern of overall horizontal distribution in most instances for Mesocyclops edax, Tropocyclops prasinus mexicanus, Ceriodaphnia lacustris, Bosmina longirostris and nauplii, but only in a few instances for Diaptomus pallidus and Daphnia parvula. Windward accumulation was common for the first 4 species and near uniform distribution was frequent for the nauplii. Vertical‐distribution trend along transect for all species rarely corresponded with the expectation. Alternation of modal depth along transect was one of the most frequently observed trends. Ways to test the hypothesis in the future are discussed.
Stabilization of native penicillin G acylase by ionic liquids
Authors: de los Ríos Antonia P. , Hernández‐Fernández Francisco J. , Rubio Manuel , Gómez Demetrio , Víllora Gloria 
Published: January 2007

AbstractFive different ionic liquids, based on dialkylimidazolium cations associated with perfluorinated and bis{(trifluoromethyl)sulfonyl}imide anions, were used to investigate the scope and limitations of these new solvents as media for penicillin G acylase‐catalyzed reactions. Deactivation of the native enzyme in ionic liquids (ILs) and in organic solvents (toluene, dichloromethane and 2‐propanol) at low water content and 40 °C was investigated using the hydrolysis of penicillin G as activity test. Native penicillin G acylase shows greater stability in IL media than in organic solvents. For example, a half‐life time of 23 h was obtained in 1‐ethyl‐3‐methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [emim+][Tf2N−], which was about 2000‐fold higher than that in 2‐propanol. An enhancement of the PGA stability was observed by the presence of substrate in ionic liquids based on tetrafluoroborate and hexafluorophosphate anions, achieving the highest increase of the half‐life time in 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim+][PF6−]), which was about 9‐fold higher than the half‐life time in the absence of substrate. Copyright © 2007 Society of Chemical Industry
Enhancing the potency of HBV DNA vaccines using fusion genes of HBV‐specific antigens and the N‐terminal fragment of gp96
Authors: Yan Jiabin , Liu Xuqing , Wang Yao , Jiang Xiaomo , Liu Huayu , Wang Mingying , Zhu Xiaodong , Wu Min , Tien Po 
Published: January 2007

AbstractBackgroundMany clinical trials show that DNA vaccine potency needs to be greatly enhanced. We have reported that the N‐terminal fragment of glycoprotein 96 (gp96) is able to produce an adjuvant effect for production of cytotoxic T‐lymphocytes (CTLs) with hepatitis B virus (HBV)‐specific peptides. Here, we report a new strategy for HBV DNA vaccine design using a partial gp96 sequence.Materials and methodsWe linked the N‐terminal 1‐355aa (N355) of gp96 to HBV genes encoding for structural proteins, the major S and middle S2S envelope proteins and the truncated core HBcAg (1‐149aa). ELISPOT, tetramer staining and intracellular IFN‐γ assay were performed to analyze the induced cellular immune responses of our DNA constructs in BALB/c mice and HLA‐A2 transgenic mice. The relative humoral immune responses were analyzed in different IgG isotypes.ResultsThe fusion genes induced 2‐ to 6‐fold higher HBV‐specific CD8+ T cells as compared to the antigens alone. There was an approximate 10‐fold decrease in the humoral immune responses with fusion genes based on HBV envelope proteins. Interestingly, the decreased humoral immune responses were not observed when antigens and plasmid encoding N355 were co‐delivered. However, an approximate 20‐fold higher antibody level was induced when linking N355 to a truncated HBcAg. Immunization by intramuscular injection resulted in predominantly IgG2a antibodies, which indicated that these vaccines preferentially prime Th1 responses.ConclusionsWe constructed highly immunogenic fusions by linking the N‐terminal fragment of gp96 to HBV antigens. Our results imply that the N‐terminal fragment of gp96 may be used as a molecular adjuvant to enhance the potency of DNA vaccines. Copyright © 2007 John Wiley & Sons, Ltd.
Development of a second‐generation oncolytic Herpes simplex virus expressing TNFα for cancer therapy
Authors: Han Z. Q. , Assenberg M. , Liu B. L. , Wang Y. B. , Simpson G. , Thomas S. , Coffin R. S. 
Published: January 2007

AbstractBackgroundTumour necrosis factor alpha (TNFα) therapy is a promising anti‐cancer treatment when combined with radiotherapy due to its potent radio sensitising effects, but systemic toxicity has limited its clinical use. Previously, non‐replicative adenovirus vectors have been used to deliver TNFα directly to the tumour, including under the control of a radiation sensitive promoter. Here, we have used an ICP34.5 deleted, oncolytic herpes simplex virus (HSV) for delivery to increase expression levels and spread through the tumour, and the use of the US11 true late HSV promoter to limit expression to where the virus replicates, i.e. selectively in tumour tissue.MethodsTNFα expression under the CMV or US11 promoter was compared on cell lines CT26, BHK and Fadu. To further compare the activities of the promoters, expression of human TNFα was analysed in the presence and absence of acyclovir‐ an inhibitor of viral DNA replication and on HSV/ICP34.5‐ non‐permissive cell line 3T6. The in vivo efficacy and toxicity of TNFα viruses were compared using A20 double flank tumour model in Balb/C mice and Fadu tumour model in nude mice.ResultsThe results demonstrated that the US11 promoter significantly reduced and delayed TNFα expression as compared to use of the CMV promoter, especially in non‐permissive cells or in the presence of acyclovir. Despite the reduced and more selective expression levels, US11 driven TNFα showed improved anti‐tumour effects compared to CMV driven TNFα, and without the toxic side effects.ConclusionsThis approach is therefore beneficial in increasing localised TNFα expression as compared to the use of non‐replicative approaches, and combines the effects of TNFα with oncolytic virus replication which is expected to further enhance the efficacy of radiotherapy in a combined treatment approach. Copyright © 2007 John Wiley & Sons, Ltd.
Morphology, constraints, and scaling of frontal sinuses in the hartebeest, Alcelaphus buselaphus (Mammalia: Artiodactyla, Bovidae)
Authors: Farke Andrew A. 
Published: February 2007

AbstractThe frontal sinuses of bovid mammals display a great deal of diversity, which has been attributed to both phylogenetic and functional influences. In‐depth study of the hartebeest (Alcelaphus buselaphus), a large African antelope, reveals a number of previously undescribed details of frontal sinus morphology. In A. buselaphus, the frontal sinuses conform closely to the shape of the frontal bone, filling nearly the entire element. However, the horncores are never extensively pneumatized, contrasting with the condition seen in many other bovids. This evidence is inconsistent with the hypothesis that sinuses are opportunistic pneumatizing agents, suggesting that phylogenetic factors also play a role in determining sinus size. Both cranial sutures and neurovasculature appear to constrain the growth of sinuses in part. In turn, the sinus also affects the growth of the parietal; apparently this element is not truly pneumatized by the sinus in most cases, but the bone's shape changes under the influence of the sinus. Furthermore, the sinuses present relatively few struts when compared with the sinuses of some other bovids, such as Ovis. By adapting methods previously developed for measuring structural parameters of trabecular bone, it is possible to quantify certain aspects of sinus morphology. These include the number of bony struts within the sinus, the spacing of these struts, and the size of individual cavities within the sinus. Some differences in the number of struts are evident between subspecies. Similarly, significant differences occur in the relative number of struts between male and female A. buselaphus, which may be related to behavior. The volume of the sinus is strongly correlated with the size of the frontal, but less so with overall cranial size. This finding illustrates the importance of choosing variables carefully when comparing sinus sizes and growth between species. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.