bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of the malaria parasite on reproductive indices of male mice
Authors: RAJI YINUSA , AKINSOMISOYE OLUMIDE S. , AZEEZ MISTURA O. 
Published: August 2006

Aim:  To investigate the impact and possible mechanism of action of the rodent malarial parasite on reproduction.Methods:  Male albino mice were infected with 15, 30 and 45%Plasmodium berghei berghei through inoculation with 107 parasitized red blood cells. Each experiment had its own control that was not infected with P. berghei berghei. Mice infected with 15%P. berghei berghei were killed on days 0, 5, 10 and 15; those infected with 30%P. berghei berghei were killed on days 0, 3, 6 and 10; and those infected with 45%P. berghei berghei were killed on days 1–7 after infection. Caudal epididymal sperm motility, counts and morphology, body and wet organ weights and hematological indices were determined.Results:  The results showed a progressive duration dependent decrease in sperm motility, sperm count and viability (P < 0.01) in parasitized mice. There were significant decreases in serum testosterone and increases in cortisol levels (P < 0.05) in the infected mice compared with the controls. There was also a progressive decrease (P < 0.05) in red blood cell count and packed cell volume. However, there was a progressive increase (P < 0.01) in white blood cell count and weight of the spleen and liver. There was no significant change in weight of the testis and epididymides.Conclusion:  The results suggest that the malaria parasite could depress male fertility indices. (Reprod Med Biol 2006; 5: 201–209)
Effect of relaxin on motility, acrosome reaction and viability of cryopreserved boar spermatozoa
Authors: MIAH ABDUL GAFFAR , HOSSAIN MD SHAROARE , TAREQ KMA , SALMA UMMAY , HAMMANO KO‐ICHI , KOHSAKA TETSUYA , TSUJII HIROTADA 
Published: August 2006

Background and Aims:   Relaxin has an important role in stimulating motility and the acrosome reaction (AR) of fresh boar spermatozoa. The objective of the present study was to determine whether relaxin can improve the motility, AR and viability of cryopreserved boar spermatozoa.Methods:   Cryopreserved boar spermatozoa were thawed, washed and incubated at 37°C for 4 h in modified Beltsville thawing solution supplemented with 0, 20 or 40 ng/mL relaxin. Sperm motility, AR, viability, and incorporation and oxidation of 14C‐glucose were evaluated during 0–4 h of incubation.Results:  The results show that the supplementation of relaxin (especially at 20 ng/mL) in the thawing solution improved sperm motility significantly (P < 0.05) at 1–3 h of incubation. The percentage of acrosome reacted live spermatozoa was improved significantly (P < 0.05) when the spermatozoa were treated with 20 ng/mL relaxin. Viability was not significantly (P > 0.05) improved by supplementation with relaxin. The rates of incorporation and oxidation of 14C‐glucose were increased in correlation with AR up to 4 h of incubation.Conclusion:  We conclude that relaxin can improve the sperm motility and AR, and enhance the glucose metabolism of cryopreserved boar spermatozoa. (Reprod Med Biol 2006; 5: 215–220)
Globalization and sustainable consumption of shrimp: consumers and governance in the global space of flows
Authors: Oosterveer Peter 
Published: August 2006

AbstractThe ongoing process of globalization in food provision is transforming the relationships between producers and consumers as well as the conventional role of governments in regulating the environment. Consumers are increasingly concerned about the environmental and social impacts of food production in developing countries and many are willing to take action. Conceptualizing globalization as the coming about of the network society offers an adequate basis for analysing transitions in food governance including new ways of consumer involvement. The case of shrimp produced through aquaculture in Thailand and consumed worldwide shows how innovative food governance arrangements appear in the context of global modernity. Authority and power in such arrangements are shifting away from national governments and towards producers, processors, traders and consumers along the supply chain.
Understanding postorganic fresh fruit and vegetable consumers at participatory farmers’ markets in Ireland: reflexivity, trust and social movements
Authors: Moore Oliver 
Published: August 2006

AbstractThis paper examines how trusting relations between consumers and vendors of organic fresh fruits and vegetables (FFVs) in a particular type of farmers’ market (FM) in Ireland are established and maintained, and what the implications of this are. First, the food system is outlined, and then its attendant problems. These problems have led to various solutions, two of which are organic food and FMs. Then, the growth in these two areas is outlined, as is the accompanying growth in the academic literature on these two areas, some of which overlaps. Various pressures, including in particular the increasing distance food travels and disconnected stallholders and products at the FM, are suggested. In light of this, a need to apply an understanding of the reflexive consumer, trust and social movements is suggested. It is found that the consumers interviewed act reflexively by choosing to go to these FMs. They prioritize the trusting relationships built up through repeated personal contact at these FMs over and above organic certification. Along with and as part of this, they prioritize local, fresh, seasonal ‘chemical‐free’ FFVs over and above imported certified organic produce. Various aspects of collective identity formation, including modes of behaviour, objects and stories, and language, are involved in this process. These elements, to some extent, act as a buffer against the pressures of distance and disconnection. Along with this, the essential meaning of the word organic is, in this particular context, reconstructed to include various socio‐environmental values missing from some certified organic produce. The word postorganic is suggested. The main methodologies used are semistructured in‐depth interviews and participant observation.
Political consumerism between individual choice and collective action: social movements, role mobilization and signalling
Authors: Holzer Boris 
Published: August 2006

AbstractThe notion of political consumerism has two implications. First, consumers wield some kind of power that they can use to effect social change through the marketplace. Second, political consumerism refers to and somehow combines the rationalities of two subsystems, politics and the economy. Yet regarding their everyday, individualized shopping decisions, consumers do not appear to command a great deal of power. What kind of influence, then, can individual economic decisions have on producers? Is that influence robust enough to attribute power to consumers? And if consumers do indeed have power, how can we conceive the implied translation of political concerns into the monetary logic of the economy? An answer to those questions needs to take into account the societal context of political consumerism. This paper analyses how political consumerism relates to the functional differentiation of modern society and how social movements are fundamental to understanding it. Through what I shall call role mobilization, social movements turn the role sets of their supporters into transmission belts for political objectives, and by authoritatively communicating those objectives, they provide signals to producers, who otherwise would not know a great deal about their consumers’ preferences.
CHROMATIC REGULATION OF QUANTUM YIELDS FOR PHOTOSYSTEM II CHARGE SEPARATION, OXYGEN EVOLUTION, AND CARBON FIXATION IN HETEROCAPSA PYGMAEA (PYRROPHYTA)1
Authors: Kroon Bernd , Prézelin Barbara B. , Schofield Oscar 
Published: August 2006

ABSTRACTOperational and maximum quantum yields for system (PSII) charge separation, oxygen evolution, and carbon fixation were quantified and compared for Heterocapsa pygmaea Loeblich, Schmidt et Sherley populations chromatically adapted to white, green, blue, and red light. Significant variability in quantum yields was induced by chromatic adaptation alone or when chromatically adapted cells were suddenly exposed to biased light fields (i.e. white light). Results indicated a close coupling between the variability in quantum yields for PSII charge separation and oxygen evolution, but not between quantum yields for oxygen evolution and carbon fixation. But not between quantum yields for oxygen evolution and carbon fixation. The ability to regrlate and optimize light energy distribution between PSII and photosystem I (PSI) appears to be the mechanism underlying chromatic adaptation for PSII charge separation and oxygen evolution. Conceptually, the resulting impacts on PSI cyclic electron transport rates could account for observed variability in quantum yields for oxygen evolution and some variability in quantum yields for carbon fixation. Similarly, enzymatic processes associated with organic carbon synthesis appeared to be variably dependent on spectral growth irradiances and contributing to the observed variability in quantum yields for carbon fixation. The relevance of these findings to the in situ primary production is discussed.
THE RPS12 GENE IN SPROGYRA MAXIMA (CHLOROPHYTA) AND ITS EVOLUTIONARY SINGNIFICANCE1
Authors: Lew Kathey A. , Manhart James R. 
Published: August 2006

ABSTRACTThe str operon consists fo four genes in eubacteria. Portions of his operon are conserved in the chloroplast genomes of green algae and land plants. In land plant chloroplasts, the str operon comprises only two genes, rps12 and rps7, and is arranged in a trans‐spliced state. Since no other previously studied chloroplast genome contains this arrangement, and because the charophyte lineage is the sister group of land plants, we chose to look for this arrangement in the Charophyceae. The two str genes, rps12 and rps7, present in the chloroplasts of Spirogyra maxima Hanssall, were identified by hybridization of a Southern blot and requenced. The results indicate that Spirogyra contains a str operon almost identical to that of land plant chloroplasts. Based upon the structure of the operon in other chloroplasts and eubacterial genomes, the trans‐spliced state most likely evolved early within the charophyte lineage.
MOLECULAR ANALYSIS REVEALS CRYPTIC DIVERSITY IN PORPHYRA (RHODOPHYTA)1
Authors: Stiller John W. , Waaland J. Robert 
Published: August 2006

ABSTRACTThe small subunit ribosomal RNA (SSU rRNA) gene was amplified from 15 species of the red alga Porphyra and digested with restriction enzymes to generate data for species identification. The subset of species selected for phylogenetic analysis was P. cuneiforms (Setchell et Hus) Krishnamurthy, P. nereocystis anderson, P. schizophylla Hollenberg et Abbott, P. thuretii Setchell et Dawson and Porphyra 1674. Bangia sp. was used as an out‐group. Restriction sites were mapped and used as characters in parsimony and maximum likelihood analysis. The phylogenetic hypotheses generated were compared statistically to possible alternative phylogenies based on traditional morphological taxonomic characters. The results indicate that the current subgenera in Porphyra do not represent monophyletic groups and that traditional morphological and ecological taxonomic characters alone may not be adequate for definitive species identification and cannot be relied on as an indication of Porphyra have large insertions in the SSU gene that are apparently splicesd from the final SSU rRNA molecule. The possible character, distribution and potential significance of these putative introns are discussed.
PREDICTING DESICCATION STRESS IN MICROSCOPIC ORGANISMS THE USE OF AGAROSE BEADS TO DETERMINE EVAPORATION WITHIN AND BETWEEN INTERTIDAL MICROHABITATS1
Authors: Brawley Susan H. , Johnson Ladd E. 
Published: August 2006

ABSTRACTWe describe an easy and inexpensive way to determine whether intertidal microhabitats remain wet during tidal emersion. This new technique uses agarose beads (120 üm diameter when fully hydrated) that shrink in a graded fashion as they dry. The agarose beads allow variability in surface wetness to be gauged over distances of less than 1 mm. Describe this parameter of microclimate is important in order to predict the likelihood and spatial pattern of survival of settled larvae, reproductive propagules, and other microscopic stages in the life histories of organisms growing in intertidal and other water‐stressed environments. For the brown seaweed Pelvetia fastigiata (J. Ag.) DeToni (Fucales, Phaeophyta), the use of agarose beads demonstrated that survival of zygotes during tidal emersion was highes at those sites that remain damp. Temperature alone was found to be an unreliable measure of wetness within a single microhabitat (e.g. red algal turf).
RELATIONSHIP BETWEEN NUCLEOSIDE DIPHOSPHATE KINASE ACTIVITY AND LIGHT‐LIMITED GROWTH RATE IN THE MARINE DIATOM THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE)1
Authors: Berges John A. , Harrison Paul J. 
Published: August 2006

ABSTRACTLight‐limited cultures of the marine diatom Thalassiosira pseudonana (Hustedt) Hasle and Heimdal (3H clone) were grown over a range of growth rates between 0.06 and 1.64 d−1. Variations in cell volume, cell quotas of carbon, nitrogen, and protein, and maximal activity of the enzyme nucleoside diphosphate kinase (NDPK) were measured and examined as a function of growth rate. NDPK from T. pseudonana showed Km values of 0.24 and 0.68 mM for thymidine 5′‐diphosphate and adenosine 5′‐triphosphate (ATP), respectively, which are similar to those found for NDPK from a variety of organisms, from bacteria to mammals. An apparent activation enthalpy of 3.52 kCal·mol−1 was determined from Arrhenius plots. No thermodynamic transition points were noted over a temperature range from 10° to 25°C. NDPK activity was significantly correlated with growth rate but not with cell volume, carbon, nitrogen, or protein; for interspecific comparisons, normalization of enzyme activity to cell number may be most meaningful. NDPK activity per cell versus growth rate followed a U‐shaped relationship, being relatively constant between 0.5 and 1.0 d−1 and rising at higher and lower growth rates. Over this range, enzyme activity may be regulated by substrate concentration (ATP or other nucleoside triphosphates) or by adenylate energy charge. At higher growth rates where energy charge and substrate concentrations are probably high, changes in enzyme concentration appear to be required. The reasons for a rise in enzyme activity at low growth rate is unclear. Simultaneous measurement of nucleoside di‐ and triphosphate levels alongside NDPK measurements may help clarify the relationship, but these preliminary experiments indicate that NDPK is of limited usefulness as an index of in situ growth rate.
INTRACELLULAR LOCALIZATION OF THE TASTE/ODOR METABOLITE 2‐METHYLISOBORNEOL IN OSCILLATORIA LIMOSA (CYANOPHYTA)1
Authors: Bafford Richard A. , Seagull Robert W. , Chung Si‐Yin , Millie David F. 
Published: August 2006

ABSTRACTThe monoterpene derivative, 2‐methylisoborneol (MIB), is produced by many blue‐green algae and often is responsible for the “musty” taste/odor in aquaculturally raised finfish and potable water supplies. Although previous researchers have suggested that taste/odor metabolites are partitioned among cell constituents and that coregulation with pigment biosynthesis occurs, no structural evidence for these hypotheses exists. MIB was localized in cells of Oscillatoria limosa (Roth) Agardh at the ultrastructural level using standard gold‐labeled antibody techniques. There was no apparent relationship between age of the cells and MIB synthesis; cells that were and were not undergoing active division had similar amounts of MIB label. There was no consistent partitioning of MIB label within cells. However, occasionally, specific label was observed along photosynthetic lamellae, suggesting a potential linkage of MIB synthesis and/or binding to the pigment systems.
FLAVODOXIN EXPRESSION AS AN INDICATOR OF IRON LIMITATION IN MARINE DIATOMS1
Authors: Roche Julie La , Murray Helen , Orellana Mónica , Newton Jan 
Published: August 2006

ABSTRACT We have prevously shown that a marine chlorophyte expressed flavodoxin under iron limitation but not under other nutrient stress conditions. Here we use polyclonal antiserum raised against the diatom Phaeodactylum tricornutum Bohlin to show that a similar response is observed in this species. Using our antibody, western blotting techniques, and standard colorimetric detection (4‐chloro‐1‐naphthol), we can detect at least a 25–50‐fold increase in flavodoxin in iron‐depleted compared to iron‐replete cells. In iron‐limited batch cultures of P. tricornulum, flavodoxin accumulation was inversely proportional to growth rate and was not detectable in cultures containing initially more than 750 nm of iron. We demonstrated that the accumulation of flavodoxin under iron stress is widespread among marine diatoms and that it may be possible to use the presence or absence of flavodoxin in natural marine diatom assemblages to detect iron limitation. However, our polyclonal antisera appears to be specific for diatoms and did not cross‐react with Synechococcus sp., Micromonas pusilla (Butcher) Manton et Parke, Dunaliella tertiolecta Butcher, Chlorella sp., Emiliania huxleii (Lohm.) Hay et Parke, or Isochrysis galbana Parke. A reverse bioassay experiment was conducted with natural phytoplankton assemblages containing mainly diatoms from Long Island Sound and in shelf waters near Cape Hatteras, two areas not suspected to be iron‐limited. Although flavodoxin was not detected in situ in these areas, natural populations of diatoms driven into iron limitation expres.sed flavodoxin. Flavodoxin was detected in mats of the diatom Rhizosolenia castracanei Cleve collected from the Equatorial Pacific during a JGOFS cruise in 1992, consistent with the hypothesis that iron may be limiting in this high‐nutrient, low‐chlorophyll region.
ACCLIMATION OF THE PHOTOSYNTHETIC APPARATUS OF PALMARIA PALMATA (RHODOPHYTA) TO LIGHT QUALITIES THAT PREFERENTIALLY EXCITE PHOTOSYSTEM I OR PHOTOSYSTEM II1
Authors: Sagert Sigrid , Schubert Hendrik 
Published: August 2006

ABSTRACT Acclimation of the photosynthetic apparatus to light absorbed primarily by phycobilisomes (which transfer energy predominantly to photosystem II) or absorbed by chlorophyll a (mainly present in the antenna of photosystem I) was studied in the macroalga Palmaria palmata L. In addition, the influence of blue and yellow light, exciting chlorophyll a and phycobilisomes, respectively, ivas investigated. All results were compared to a white light control. Complementary chromatic adaptation in terms of an enhanced ratio of phycoerythrin to phycocyanin under green light conditions was observed. Red light (mainly absorbed by chlorophyll a) and green light (mainly absorbed by phycobilisomes) caused an increase of the antenna system, which was not preferentially excited. Yellow and blue light led to intermediate states comparable to each other and white light. Growth was reduced under all light qualities in comparison to white light, especially under conditions preferably exciting phycobilisomes (green light‐adapted algae had a 58% lower growth rate compared to white light‐adapted algae). Red and blue light‐adapted algae showed maximal photosynthetic capacity with white light excitation and significantly lower values with green light excitation. In contrast, green and yellow light‐adapted algae exhibited comparable photosynthetic capacities at all excitation wavelengths. Low‐temperature fluorescence emission analysis showed an increase of photosystem II emission in red light‐adapted algae and a decrease in green light‐adapted algae. A small increase of photosystem I emission teas also found in green light‐adapted algae, but this was much less than the photosystem II emission increase observed in red light‐adapted algae (both compared to phycobilisome emission). Efficiency of energy transfer from phycobilisomes to photosystem II was higher in red than in green light‐adapted algae. The opposite was found for the energy transfer efficiency from phycobilisomes to photosystem I. Zeaxanthin content increased in green and blue light‐adapted algae compared to red, white, and yellow light‐adapted algae. Results are discussed in comparison to published data on unicellular red algae and cyanobacteria.
THE FLAGELLAR DEVELOPMENT CYCLE OF THE UNIFLAGELLATE PELAGOMONAS CALCEOLATA (PELAGOPHYCEAE)1
Authors: Heimann Kirsten , Andersen Robert A. , Wetherbee Richard 
Published: August 2006

ABSTRACT Vegetative cells of Pelagomonas calceolata Andersen & Saunders were confirmed to possess a reduced flagellar apparatus, consisting of a single basal body/flagellum that is not accompanied by either flagellar roots or a barren basal body. Just prior to division, the parental flagellum retracts (or is abscised) as two new basal bodies/flagella arise de novo. During cytokinesis the parental basal body segregates with a new basal body/flagellum, briefly producing a progeny cell typical of other known uniflagellates (i.e. containing a basal body/flagellum and accompanying barren basal body). The parental basal body then disintegrates or “transforms” out of existence, leaving both progeny cells with a single basal body/flagellum (i.e. neither progeny cell possesses any vestige of a mature flagellum/basal body). Pelagomonas calceolata belongs to a lineage of chromophyte algae characterized by having a reduced flagellar apparatus, but it is the only known species, not only in this lineage but among all eukaryotes, to have undergone the complete elimination of the mature flagellum /basal body.
THE FUCUS (PHAEOPHYCEAE) SPERM RECEPTOR FOR EGGS. II. ISOLATION OF A BINDING PROTEIN WHICH PARTIALLY ACTIVATES EGGS1
Authors: Wright Philip J. , Callow James A. , Green Jonathan R. 
Published: August 2006

ABSTRACT An in vitro binding assay involving egg plasma membrane vesicles (PMVs) of Fucus serratus L. and proteins contained in a KCl extract of sperm has been used to identify a sperm protein involved in egg binding. High‐performance gel filtration (HPGF) separated the sperm KCl extract into several major fractions, and a protein (apparent M, 60 kDa) was identified as being involved in binding to the egg PMVs. This protein ran on denaturing sodium dodecyl sulfate (SDS)gels with an apparent molecular weight of 27 kDa. This suggests that either the native form of the protein is a dimer or the molecular weight on HPGF is an artifact caused by high ionic strength buffer promoting hydrophobic interactions. When KCl‐sol‐uble proteins were separated by SDS‐polyacrylamide gel electrophoresis (PAGE), blotted onto nitrocellulose, and incubated with biotinylated egg PMVs, these bound to a band at 27 kDa, confirming the role of this protein. Addition of the Fucus sperm extract or HPGF fractions containing the binding protein to eggs in the absence of sperm induced the release of polysaccharides onto the egg cell surface. This labeling was patchy, in contrast to the uniform release of polysaccharides observed when sperm were added to eggs. The monoclonal antibody (MAb) FS17 was raised against the 27‐kDa sperm protein. It labeled the sperm body and both flagella by immunofluorescence, though the sperm had to he permeabilized to observe labeling, suggesting that the epitope recognized is not exposed at the cell surface. Addition of FS17 to the KCl extract in the binding assay reduced subsequent binding of egg PMVs. Removal of the 27‐kDa protein recognized by FS17 from the sperm extract prevented the binding of egg PMVs in the binding assay and the triggering of the patchy release of polysaccharides when added to eggs. Overall the results suggest that the 27‐kDa sperm protein is involved in binding to the egg plasma membrane and can trigger partial activation of the egg.