bluuebunny/crossref_metadata_2025_split huggingface dataset:
PHOSPHORUS LIMITATION AND CARBON METABOLISM IN A UNICELLULAR ALGA: INTERACTION BETWEEN GROWTH RATE AND THE MEASUREMENT OF NET AND GROSS PHOTOSYNTHESIS1
Authors: Harris Graham P. , Piccinin B. Beryl 
Published: November 2004

ABSTRACT Chlamydomonas reinhardii Dangeard was grown in continuous culture under P limitation at a range of dilution rates. Carbon uptake measurements were performed using double isotope (12C/14C) techniques and the fluxes of carbon in the light and dark were analysed over the range of growth rates. 14C uptake was shown to be equal to gross photosynthesis only at maximum relative growth rates; at low relative growth rates 14C uptake approximated net photosynthesis. The altered pattern of C uptake was found to be due to the suppression of dark respiration in the light and the release of 14C02 from respiratory pathways at low relative growth rates. Metabolic channelling of 14C from photosynthetic pathways to respiratory pathways occurred at low growth rates as the specific activity of the respired CO2 reached 45% of the input gas mixture. These data are discussed in the light of the controversy concerning the measurement of gross and net photosynthesis in natural populations and in the light of models of 14C uptake in single celled algae. Existing models are shown to be adequate for high relative growth rates but not for low relative growth rates under P limitation.
GROWTH, YIELD AND MORPHOLOGY OF ASCOPHYLLUM NODOSUM (PHAEOPHYTA) UNDER CONTINUOUS AND INTERMITTENT SEAWATER SPRAY CULTURE REGIMENS1
Authors: Rheault Robert B. , Ryther John H. 
Published: November 2004

ABSTRACTGrowth and yield of the brown alga Ascophyllum nodosum (Le Jolis) were measured under various regimens of seawater spray culture. One‐hour periods of desiccation throughout the day and night and cessation of spray throughout the night did not affect growth relative to that in continuous spray. Desiccation for four hours during the day resulted in death. Changes in morphology from the normal intertidal growth form to that resulting from spray culture are described.
A SUSPECTED CASE OF MYCOPHYCOBIOSIS BETWEEN MYCOSPHAERELLA APOPHLAEAE (ASCOMYCETES) AND APOPHLAEA SPP. (RHODOPHYTA)1
Authors: Kohlmeyer Jan , Hawkes Michael W. 
Published: November 2004

ABSTRACT Apophlaea lyallii Hooker f. et Harvey and A. sinclairii Harvey in Hooker et Harvey, endemic Rhodophyta from New Zealand, were found to harbor a systemic fungus, Mycosphaerella apophlaeae Kohlmeyer. The algae occur on rocks in the upper intertidal zone and are resistant to desiccation and insolation. These suspected symbiotic associations which are similar to, but different from, lichens, are considered mycophycobioses. This is the first report of a supposed mycophycobiosis in members of the Rhodophyta.
THE LIPID COMPOSITION OF THORACOSPHAERA HEIMII: EVIDENCE FOR INCLUSION IN THE DINOPHYCEAE1
Authors: Jones Gary J. , Nichols Peter D. , Johns R. B. 
Published: November 2004

ABSTRACTThe fatty acid, sterol and chlorophyll composition of the calcified, unicellular alga Thoracosphaera heimii (Lohmann) Kamptner are reported. The presence of 4,23,24‐termethyl‐5α‐cholest‐22E‐en‐3β‐ol (dinosterol), 4,23,24‐trimethyl‐5α‐cholest‐22E‐en‐3‐one (dinosterone) and the predominance of C18, C20 and C22 unsaturated fatty acids, including the acid 18:5ω3, indicates that T. heimii is a dinoflagellate. The fatty acid: sterol ratio (1.3), is typical of dinoflagellates. The geochemical significance of dinosterone, the high relative concentration of 4‐desmethyl‐5α‐stanols and the role of 23‐methyl‐5α‐cholest‐22E‐en‐3β‐ol in the biosynthesis of dinosterol in T. heimii are also discussed.
PHOTOSYNTHETIC QUANTUM EFFICIENCIES OF PHYTOPLANKTON FROM PERENNIALLY ICE COVERED ANTARCTIC LAKES1
Authors: Seaburg Kenneth G. , Kaspar Mark , Parker Bruce C. 
Published: November 2004

ABSTRACTA recently introduced approach far estimating the photosynthetic quantum efficiency (φ) of a freshwater or marine phytoplankton community has been applied for the first time to high latitude polar ecosystems, namely four lakes of southern Victoria Land, Antarctica. Values for φ at various depths ranged from 0.0022–0.1560 when calculated using a recommended mean extinction coefficient for phytoplankton (i.e. &#x006b;̄c= 0.016). By contrast, φ ranged from 0.0037–0.0760 when calculated using an empirically estimated value for &#x006b;̄c of 0.0328. If the recommended &#x006b;̄c= 0.016 more closely approaches an accurate estimate, then the φ valves indicate that the phytoplankton convert light to organic carbon more efficiently than elsewhere. However, if the empirically derived &#x006b;̄c= 0.0328 more closely approaches an accurate estimate, then the φ values indicate the phytoplankton trap light more efficiently than elsewhere. Although we have not resolved whether light conversion (φ) or light trapping are more efficient, the results show that the phytoplankton of these Antarctic lakes are well adapted to performing photosynthesis under extremely low light conditions.
REGULATION OF A GLUCOSE TRANSPORT SYSTEM INSTICHOCOCCUS BACILLARIS1
Authors: Carthew Richard W. , Hellebust Johan A. 
Published: November 2004

ABSTRACTGlucose and related non‐metabolizable analogs were transported into cells ofStichococcus bacillarisNaeg. By a specific and active transport system. Glucose transport capacity was stimulated eight‐fold by incubation in medium of low osmotic potential (0.09 osM). Stimulation occurred over 24 h in the dark and over 72 h in low osmotic medium. Inhibition of protein synthesis prevented any transport, stimulation from occurring. Kinetic studies revealed that the stimulation caused an increase in Ike maximal velocity of transport and did not affect the half‐saturation constant for transport. It was concluded that incubation of cells in the dark or in low osmolar medium induces a synthesis of the transport system. The glucose analog 2‐deoxy‐D‐glucose was only phosphorylated to a limited extent upon entry into the cells, and the free sugar accumulated linearly in dark pre‐incubated tells for a period of at least six minutes to reach an intracellular/extracellular concentration ratio of almost 300. Glucose, in contrast, was rapid h converted to sucrose and other cell constituents. Cells incubated 24 h with, glucose or 6‐deoxy‐D‐glucose did not exhibit any altered transport system activity. Cells incubated 24 h with 7 mM dibutyryl cAMP exhibited a 2.5‐fold stimulation of transport activity. No stimulation was observed in cells treated only 30 min with dibutyryl cAMP.
EFFECTS OF PHOTOCYCLES AND PERIODIC AMMONIUM SUPPLY ON THREE MARINE PHYTOPLANKTON SPECIES. I. CELL DIVISION PATTERNS1
Authors: OlsonM Robert J. , Chisholm Sallie W. 
Published: November 2004

ABSTRACTCell division patterns in Thalassiosira weissflogii (Grun.), Hymenomonas carterae (Braarud and Fagerl), and Amphidinium carteri (Hulburl) grown in cyclostat culture were analyzed as functions of the periodic supply of light and the limiting nutrient (ammonium) and of combinations of these two factors. In all three species, division patterns were phased by light/dark cycles in N–limited as well as N–replte conditions, and also to ammonium pulses in N–limited growth in continuous light. Both the degree and timing of the cell cycle phasing varied among species. When both stimuli were present, the influence of the photocycle overrode the N–pulse stimulus in H. carterae and A. carteri. while in T. weissflogii, division was always phased by the timing of the N–pulse regardless of the phase angle between the photocycle and the pulse.
EFFECTS OF PHOTOCYCLES AND PERIODIC AMMONIUM SUPPLY ON THREE MARINE PHYTOPLANKTON SPECIES. II. AMMONIUM UPTAKE AND ASSIMILATION1
Authors: Wheeler Patricia A. , Olson Robert J. , Chisholm Sallie W. 
Published: November 2004

ABSTRACTThe relative influence of the photoperiod and of periodic ammonium pulses in entraining the cell division cycle in nitrogen‐limited cyclostat cultures differs dramatically in Hymenomonas carterae Braarud and Fagerl, Amphidinium carteri Hulburt and Thalassiosira weissflogii Grun. We examined how each species processes an NH4+ pulse at various times during the cell cycle and the L/D cycle. Rates of NH4+ uptake and changes in cellular concentrations of NH4+, free amino acids, and protein were examined after the addition of an NH4+ pulse. Depletion of NH4+ from the medium occurred earlier when the pulse was given at the beginning of the light period than at the beginning of the dark period in H. carterae and A. carteri. Depletion took longer in the T. weissflogii cultures and the kinetics were similar during both stages of the photocycle in this species. Similarly, the temporal phasing and maximum pool sizes varied with timing of the NH4+ pulse in H. carterae and A. carteri but complete assimilation was relatively rapid. More persistent pools of NH4+ and free amino acids accumulated in T. weissflogii, and the patterns of assimilation varied little as a function of the timing of the pulse with respect to the photocycle. Although nitrogen metabolism occurred rapidly in nitrogen‐limited H. carterae and A. carteri, the entrainment of the cell division cycle by the photoperiod resulted in a large degree of uncoupling between completion of nitrogen assimilation and cell division. It is hypothesized that the strong entrainment of the cell division cycle of T. weissflogii by NH4+ pulses results from a relatively slow rate of nitrogen metabolism.
The role of tumour necrosis factor‐α in renal dysfunction following mild haemorrhage in rats
Authors: Sato Hiroaki , Tanaka Toshiko , Kita Toshiro , Yamaguchi Hiroki , Tanaka Noriyuki 
Published: November 2004

SummaryMild haemorrhage occasionally causes delayed death following failure of kidney or multiple organs, but the precise mechanisms have not yet been identified. We investigated the role of tumour necrosis factor‐α (TNF‐α), known as a major pro‐inflammatory cytokine that leads to multiple organ failure, on the renal damage induced by mild haemorrhage. A mild haemorrhagic state was induced in male anaesthetized rats by bleeding via a common carotid catheter for 20 min at 16.7% of total body blood, 1.09 ml/100 g body weight, without fluid resuscitation. Mean arterial pressure and heart rate decreased soon after haemorrhaging but returned to baseline level up to 5 h after bleeding. TNF‐α mRNA expression in the kidney and serum TNF‐α levels were highest at 1 h after bleeding. Intraperitoneal pretreatment with FR167653, an inhibitory compound of TNF‐α production, as well as of interleukin (IL)‐1β, significantly inhibited the increase in TNF‐α. The inflammatory cell infiltration and tubular cell injury induced by haemorrhage were suppressed, and the renal dysfunction was dramatically improved by the FR167653 treatment. The morphological changes were also less in the treated group than in those that had not been treated. TNF‐α has been reported to have striking effects on IL‐1β release and activation of neutrophils, and to play a pivotal role in the expression of the other pro‐inflammatory cytokines. Our data show that endogenously‐derived TNF‐α does play a key role in the renal dysfunction during mild haemorrhage. These results should be useful to forensic pathologists to explain the pathogenesis of renal dysfunction induced by a mild haemorrhage and to identify the cause of death where there are no significant morphological changes after mild haemorrhage.
Vascular endothelial growth factor reduces mural cell coverage of endothelial cells and induces sprouting rather than luminal division in an HT1080 tumour angiogenesis model
Authors: Fujimoto Akihisa , Onodera Hisashi , Mori Akira , Isobe Naoki , Yasuda Seiichi , Oe Hideaki , Yonenaga Yoshikuni , Tachibana Tsuyoshi , Imamura Masayuki 
Published: November 2004

SummaryVascular endothelial growth factor (VEGF) plays a central role in tumour angiogenesis. In a mouse intramuscular tumour model using VEGF‐transfected HT1080 human fibrosarcoma, we investigated the morphological features and patterns of remodelling in size‐matched tumours. Compared with the control tumours (C group), the VEGF‐transfected tumours (V group) showed vigorous neovascularization with larger vessels. Fenestrations and disruptions of endothelia were specific to the V group. Three types of vascular remodelling, i.e. sprouting, luminal division and intussusceptive microvascular growth, were present in both groups. Morphometric analyses revealed that mural cell coverage of the endothelial cells was significantly smaller in the V group compared with that in the C group (V group, 28.2 ± 18.6%; C group, 41.6 ± 21.1%; P < 0.0001). To determine the prevalence of remodelling patterns, the occurrences of abluminal and luminal processes on endothelial cell surfaces were quantified. Abluminal processes are defined as cytoplasmic protrusions of the abluminal membrane of endothelial cells, which can vary from tiny spurs to solid sprouts of the cell. On the other hand, luminal processes are defined as intraluminal protrusions of the endothelial cell membrane, including various membranous changes from filiform processes to rather thick cytoplasmic bulges. An abluminal process is thought to represent an initial morphological change in sprouting type angiogenesis, and a luminal process to be a sign of implementation of luminal division. The frequency of abluminal processes was significantly higher in the V group than in the C group (V group, 0.243 ± 0.138/µm; C group, 0.114 ± 0.101/µm; P < 0.0001). In contrast, the number of luminal processes on the endothelial cells per micrometre was statistically comparable between the groups (V group, 0.285 ± 0.252/µm; C group, 0.309 ± 0.236/µm, P = 0.381). These results indicate that sprouting is the main mode of VEGF‐induced tumour angiogenesis.
A simple method for measuring tiller volume of grasses
Authors: Sbrissia A. F. , Da Silva S. C. , Molan L. K. , Sarmento D. O. L. , Andrade F. M. E. , Lupinacci A. V. , Gonçalves A. C. 
Published: November 2004

AbstractA simple method for measuring tiller volume of grasses is described. The equipment, based on the communicant pipe principle, was built using a PVC pipe linked to a laboratory volumetric pipette. The results showed a high degree of consistency and were similar to empirical results published in the literature, indicating that tiller volume of grasses can be easily measured with this technique.
Changes during growth in the nutritive value of components of berseem clover (Trifolium alexandrinum L.) under different cutting treatments in a Mediterranean region
Authors: De Santis G. , Iannucci A. , Dantone D. , Chiaravalle E. 
Published: November 2004

AbstractThe nutritive value of berseem clover (Trifolium alexandrinum L.) may be influenced by changes in the nutrient concentrations of morphological fractions as a consequence of cutting treatment. The aim of this study was to evaluate the effects of different cutting treatments on the nutritive value of herbage and leaf and stem components in two Mediterranean berseem genotypes during growth in order to develop management approaches for harvesting forage with a high nutritive value. Spring growth of genotypes of Egyptian (cv. Giza 10) and Italian (cv. Sacromonte) origins was harvested in each of 2 years beginning 196 days after sowing and thereafter every 6 days (twelve harvests in total) to measure dry matter (DM) yield and nutritive value. Cutting treatments were initiated at sixth internode elongation (A) and early flowering (B) and there was an uncut control treatment (C). In vitro digestibility of organic matter (IVOMD) and crude protein (CP) concentration were determined for leaf, stem and total forage of each cultivar at each harvest. For both cultivars, in the uncut treatment (C), DM yield increased linearly to a maximum of 14 800 kg ha−1, on average, by 250 days after planting, the same time at which stem DM accumulation peaked, whereas the nutritive value, in terms of IVOMD and CP concentration, declined with age, coinciding with a reduction in leaf:stem ratio (LSR) from 1·00 to 0·30. Plant parts differed (P < 0·01) in nutritive value with stems being of lower nutritive value than leaves, in the two cutting treatments. There were strong positive correlations between LSR and herbage IVOMD and CP concentration, in both cutting treatments, indicating that, during growth, part of the changes in IVOMD and CP concentration of berseem clover plants was due primarily to the changes in the LSR. Defoliation induced a considerable reduction in DM yield, but an increase in the LSR and a small increase in nutritive value. Plants cut at the sixth internode elongation (A) showed a small proportional decrease (0·19) in total DM yield, but higher LSR values and similar or higher IVOMD and CP concentration than initiating cutting at early flower (B). Delaying defoliation to the early flowering stage (B) increased the proportion of stems and, therefore, decreased nutritive value. Therefore, harvest management in which cuts are applied at the stage of sixth internode elongation appears to be the most favourable for obtaining relatively high yields of forage with high nutritive value in berseem clover grown in Mediterranean regions.
Genetic diversity of Indian native cattle breeds as analysed with 20 microsatellite loci
Authors: Mukesh M. , Sodhi M. , Bhatia S. , Mishra B. P. 
Published: November 2004

SummaryThe aim of the present study was to assess the genetic variation and establish the relationship amongst the three Indian zebu cattle breeds using 20 bovine‐specific microsatellite markers. A total of 136 unrelated DNA samples from Sahiwal (SC), Hariana (HC) and Deoni (DC) breeds of cattle were genotyped to estimate within and between breed genetic diversity indices. The estimated mean allelic diversity was 5.2, 6.5 and 5.9 in SC, HC and DC, respectively, with a total of 167 alleles. The average observed and expected heterozygosity for the population varied from 0.42 (SC) to 0.59 (DC), and from 0.61 (SC) to 0.70 (DC), respectively. Low values of genetic variability estimates were observed in SC when compared with DC and HC, indicating some loss of variability because of its relatively small population size. From global F‐statistics a significant deficit of heterozygotes of 24.2% (p < 0.05) was observed for each one of the analysed breeds whereas the total population had a 32.8% (p < 0.05) deficit of heterozygotes. The FST estimates demonstrated that approximately 88.7% of the total genetic variation was because of the genetic differentiation within each breed. Pair‐wise breed differentiation, Nei's standard and DA genetic distance estimates revealed relatively close genetic similarity between HC and DC in comparison with SC. In the UPGMA‐based phylogenetic tree constructed from the genetic distances, HC and DC were grouped together in one cluster and SC in the other. The estimated time of divergence suggested a separation time of approximately 776 years between DC and HC, and a comparatively longer period (1296 years) between DC and SC.
Intravenous drug abuse and Type 1 diabetes: financial and healthcare implications
Authors: Saunders S. A. , Democratis J. , Martin J. , Macfarlane I. A. 
Published: November 2004

AbstractAims  To determine the morbidity, mortality and healthcare costs of intravenous drug‐abusing patients with Type 1 diabetes (IVDA‐DM), who are admitted to hospital.Methods  Retrospective case note analysis of admissions, complications and cost estimation over a 6‐year period. Each drug‐abusing patient (IVDA‐DM) (n = 9) was compared with two controls (n = 18) with Type 1 diabetes but without a history of intravenous drug abuse (DM‐controls). Admissions were also analysed for patients with intravenous drug abuse, but without Type 1 diabetes (IVDA‐controls) (n = 198). Admissions were at a University teaching hospital in Liverpool, UK. DM‐controls were drawn from a population attending diabetes outpatient clinics between 1997 and 2002 at the same hospital. The main outcome measures were: the duration and healthcare costs of hospital admissions per year, outpatient attendances per year, glycated haemoglobin (HbA1c), weight, micro‐ and macrovascular complications and mortality.Results  Multiple admissions, mainly related to ketoacidosis, led to marked differences in mean (95% CI) inpatient days per year per patient [IVDA‐DM 28.1 (13.6–42.7) vs. DM‐control 1.1 (0.2–1.9); P < 0.0001], mean inpatient days per year per patient in critical care bed (IVDA‐DM 1.7 (−0.7–4.2) vs. DM‐control 0; P < 0.02) and mean costs of admission, per patient per year (£7320 vs. £230). The IVDA‐DM group frequently omitted insulin, were underweight, failed to attend as outpatients and five had died by the end of 2002. The IVDA‐controls spent considerably less time in hospital [3.4 (2.8–3.9) days per patient per year].Conclusion  IVDA‐DM patients have higher rates of diabetes complications, are admitted more frequently and have a high mortality compared with DM and IVDA‐controls. The cost of inpatient care of this small group of patients was considerable.
Changing aspirin use in patients with Type 2 diabetes in the UKPDS
Authors: Cull C. A. , Neil H. A. W. , Holman R. R. 
Published: November 2004

AbstractAims  To examine the proportion of UK Prospective Diabetes Study (UKPDS) patients with Type 2 diabetes taking aspirin regularly for the primary and secondary prevention of cardiovascular disease (CVD) before and after publication of the 1997 American Diabetes Association (ADA) Clinical Practice Recommendations and the 1998 Joint British Recommendations on the Prevention of Coronary Disease in Clinical Practice.Methods  UKPDS annual review data from 1996/7 (n = 3190) and 2000/1 (n = 2467) were used to determine the prevalence of patients taking aspirin regularly in relation to known CVD risk factors and pre‐existing CVD.Results  Patients taking aspirin regularly were more often male than female (24 vs. 20%, P = 0.0033), older (66 ± 8 vs. 62 ± 9 years, P < 0.0001) and less often Afro‐Caribbean than White Caucasian or Indian Asian (11 vs. 23 vs. 22%, respectively, P < 0.0001). Between 1996/7 and 2000/1 aspirin use in patients without pre‐existing CVD increased from 17 to 31% (P < 0.0001) and for those with pre‐existing CVD from 76 to 82% (P = 0.032).Conclusion  The majority of patients with pre‐existing CVD were taking aspirin regularly. Although aspirin use in those without pre‐existing CVD approximately doubled after publication of the ADA and Joint British Recommendations, less than two‐thirds of these high‐risk patients were being treated according to guidelines. This may relate to a lack of convincing evidence for primary CVD prevention or failure to adhere to guidelines. It may be that more trial data is needed to convince clinicians of the value of aspirin therapy in Type 2 diabetes.