bluuebunny/crossref_metadata_2025_split huggingface dataset:
Desmids and Dinoflagellates of Ecuador
Authors: Carty S. , Hall J. D. 
Published: March 2003

AbstractThe freshwater flora of Ecuador is poorly known. This report provides preliminary information about the freshwater Pyrrhophyta and two families in the Chlorophyta. There has been some work on diatoms but other groups remain unstudied. In June 2001, samples were collected as whole water or by using a 10‐mm plankton net from 52 locations in the interior (Amazonian) and Andean regions and examined within hours using a Swift field microscope. Nine additional samples from Ecuador have been provided by Dr Miriam Kannan. Amazonian sites consisted of oxbow lakes along the Rio Shiripuno, and small ponds and lakes along the road from the river to Coca. Andean sites were principally in the Cajas National Park near Cuenca. Genera in the Closteriaceae include Closterium, Gonatozygon, Spinoclosterium, and Penium. Desmidiaceae include Arthrodesmus, Bambusina, Cosmarium, Desmidium, Euastrum, Hyalotheca, Micrasterias, Pleurotaenium, Spondylosum, Staurastrum, Staurodesmus, Triploceras, and Xanthidium. Pyrrhophyta include Ceratium, Gymnodinium, Peridinium, Sphaerodinium, and Woloszynskia.
Actin Phylogeny in the Charophyta
Authors: Lewandowski J. D. , Delwiche C. F. 
Published: March 2003

AbstractPhotosynthetic green plants, the Viridiplantae, are composed of two distinct lineages, the Chlorophyta and Charophyta. The Chlorophyta include the Chlorophyceae, Trebouxiophyceae, Ulvophyceae and most prasinophytes. The Charophyta include the Mesostigmatales, the traditional charophycean green algal orders Chlorokybales, Klebsormidiales, Zygnematales, Coleochaetales and Charales, and land plants, referred to here as Embryophyceae. The Embryophyceae are embedded within the paraphyletic charophycean green algae, so land plants are, therefore best considered a specialized group of green algae adapted to terrestrial life. Due to the close evolutionary relationship between green algae and Embryophyceae, characterizing the early evolution and diversification of land plants depends on understanding phylogenetic relationships among the less extensively studied green algal members of the Charophyta. Relationships within the Charophyta have previously been based on morphology and inferred through phylogenetic analyses of molecular data that include ribosomal DNA and several genes from the chloroplast and mitochondrial genomes. To this point, however, few phylogenetic analyses of nuclear, protein‐coding genes have been conducted. We are attempting to isolate and sequence actin‐coding regions from representative members of the Charophyta. Actin is a highly conserved protein that is ubiquitous among eukaryotes; these features make actin an ideal subject for comparative sequence analysis. A major component of the cytoskeleton, actin plays a number of important roles in plant cell processes such as cell division and cytoplasmic streaming. Hence, in addition to being potentially useful for resolving organismal relationships, the evolution of the actin protein itself is intrinsic to the study of morphological evolution and development within green plants.
Phormidium Retzii (Oscillatoriales): Genotypic Variation and Phenotypic Plasticity
Authors: Casamatta D. A. , Vis M. L. , Sheath R. G. 
Published: March 2003

Abstract Phormidium retzii is one of the most commonly encountered lotic taxa in North America and has been recorded from a wide range of habitats worldwide. The genetic variability of this cosmopolitan, freshwater cyanobacterium was assessed using gene sequences and random amplified polymorphic DNA (RAPD) markers. Strains consistent with the morphological species circumscription were utilized from British Columbia, Canada to Rio Claro, Costa Rica, and from Rhode Island to Washington State, USA. In addition, some strains were from geographically close (<25 miles apart) sites. The 16S rRNA gene was sequenced for eight of the 12 strains. Sequence homology ranged from 90.95 to 98.71. The nine RAPD primers utilized yielded a total of 133 distinct bands from the 12 strains. The strains were variously related and showed great variation in pairwise genetic distances (0.23–0.83). Given the lack of sequence similarity, P. retzii as presently circumscribed most likely represents several cryptic species not clearly distinguishable with light microscopy of morphological characters. This conclusion may explain the lack of correlation between geographic proximity and genetic similarity. To assess the level of environmentally induced phenotypic plasticity of this taxon, one strain was subjected to three different current velocity and nutrient regimes (low, medium, and high) employing six stream mesocosms. ANOVAs and Bonferroni multiple comparison tests were performed with cell volumes, ratios of cell length : width and percent cover data. Low nutrient treatments elicited significantly (P < 0.05) greater cell volumes and percent cover than did high treatments. Furthermore, current velocity did not show any significant effect on cell morphology. As such, it appears that a single strain is capable of wide morphological variability in response to some environmental conditions. The results of these two studies have great implications in the utilization of cyanobacterial morphospecies concepts.
Molecular Systematics of the Subaerial Green Algal Family Trentepohliaceae (Chlorophyta; Trentepohliales) Inferred From 18 SSU rDNA Sequences
Authors: Lopez‐Bautista J. M. , Chapman R. L. , Rindi F. , Guiry M. 
Published: March 2003

AbstractRepresentatives of the monophyletic Trentepohliales are widely distributed in the tropics, subtropics, and temperate regions worldwide. They grow in soil, or are epilithic, epiphytic or endophytic. The family comprises approximately 70 species placed in at least four genera (Trentepohlia, Cephaleuros, Phycopeltis and Stomatochroon), with Trentepohlia sensu lato (including Printzina and Physolinum) accounting for half of the species in this family. PCR amplification and sequencing of the 18 SSU rDNA of 18 isolates of the Trentepohliaceae were used to assess the monophyly of the genus Cephaleuros and to determine the phylogenetic relationships among species of Trentepohlia sensu lato. Distance, Parsimony, and Maximum Likelihood analyses indicate that Trentepohlia sensu lato is basal and includes two species recently transferred to Phycopeltis (P. umbrina) and Printzina (P. lagenifera). In contrast, Cephaleuros is a derived monophyletic clade. Analysis of isolates of C. virescens, from the USA, Taiwan, and South Africa indicate that this taxon may consist of different species sharing a convergent morphology. The results of this study have implications for the taxonomy of the genera.
The Effects of Thallus Toughness and Nutritive Quality on Palatability of Antarctic Macroalgae
Authors: Peters K. J. , Amsler C. D. , Amsler M. O. , McClintock J. B. , Iken K. B. , Baker W. J. 
Published: March 2003

AbstractPalatability of macroalgae can be affected by many different factors including thallus toughness, nutritional quality (carbohydrates, lipids, proteins, ash), and the presence of deterrent secondary metabolites. Palatability bioassays were performed using two different antarctic algal grazers (the antarctic rockfish Notothenia coriiceps and the sea star Odontaster validus). These data were then compared to toughness and chemical composition data. Toughness was determined using a penetrometer and a wide range of thallus toughness was observed in individuals of differing species as well as of the same species. Some of the tougher individuals required more than 30 N of force to cut through the thallus while others required less than 1 N to break through. Each algal species is also being tested for percent composition of carbohydrates, lipids, proteins, as well as ash. It is hypothesized that the algal species with greater nutritional quality and/or less thallus toughness are more likely to be acceptable foods to consumers (NSF OPP9814538, OPP9901076).
Effects of Environmental Parameters on the Growth Characteristics of Symbiodinium SPP. Isolated from Corals
Authors: Rogers J. E. , Davis R. H. , Oliver L. M. 
Published: March 2003

Abstract Symbiodinium spp. were isolated from Porites porites (JR02F2 and RD03), Montipora capitata (JR12A7), Madracis mirabolis (RD02), Montastrea faveolata (RD04), Pocillopora damicornis (JR13E1), and an unknown coral (RD01). Growth rates and the distribution between motile gymnodinoid cells and sessile coccoid cells were determined in 200 µL cultures in 96‐well dilution plates. Clones of each isolate were maintained in L1 medium (prepared with 34 ppt sterile Gulf of Mexico water), at 26 °C with illumination provided at 100–150 mE/m2/s PAR (400–700 nm) during a 10 : 14 (light : dark) photoperiod. Under these conditions, generation times of nearly once per 24 h were observed for clones, JR02F2, RD01 and RD02, in log growth. Clone RD04 had a generation time of approximately 5 days. The fastest growing clones produced the highest percentage of motile cells (>90) during the daylight portion of the diurnal cycle. Growth characteristics of selected clones were examined over a range of salinities, temperatures and PAR intensities. Salinities ranging from 25 to 45 ppt had little if any affect on growth rate. At salinities less than 25 ppt significant decreases in growth were generally observed; no growth was common at 5 and 10 ppt. In most cases inhibitory effects of temperature were observed at temperatures greater than 29 °C. For example, generation times for JR02F2 were slightly greater at 29 °C than 24 °C, but maximal growth rates were reduced approximately 50–90% at temperatures of 32 and 34 °C, respectively. The most sensitive clone, RD04, stopped dividing after two divisions at 29 °C. The growth rate of JR02F2 and RD01 reached a maximum at PAR levels greater than 100 mE/m2/s and remained within a range of 0.75–0.85 divisions/day up to 390 mE/m2/s.
Phylogeny of Klebsormidium (Kelbsormidiales; Charophyta) Based on rbcL, atpB, coxIII and nad5 Sequence Data
Authors: Snyder S. W. , Karol K. G. , Delwiche C. F. 
Published: March 2003

AbstractThe charophycean order Klebsormidiales consists of two unbranched filamentous lineages, the fresh water Entransia and the semiterrestrial Klebsormidium. Molecular data have supported the close relationship Klebsormidiales have with land plants. A monograph exists for the European species of Klebsormidium; this monograph provides a cladistic analysis of morphological characteristics for eight Klebsormidium species, but a species level molecular phylogenetic analysis has not yet been performed for the group. We have obtained 50 strains of Klebsormidium, representing 11 morphological species, both from nature and from culture collections. Phylogenetic analyses using rbcL, atpB, coxIII and nad5 gene sequence data from these strains and 40 outgroup sequences suggest that several traditional Klebsormidium species may not be monophyletic.
The Effects of Biogenically Active Compounds on Cyclotella Meneghiniana (Bacillariophyta)
Authors: Tedrow O. , Julius M. L. , Schoenfuss H. L. 
Published: March 2003

AbstractBiogenically active compounds have been discovered in many surface water samples in Europe and North America. Wastewater effluent is identified as a major source of contamination and found to revert much of the metabolic products of these biologically active compounds back to their original form. This presentation explains methodology for determining the effects of these contaminants through a newly developed bioassay, examining the physiological response of a diatom to these compounds. Diatoms represent an important aspect of the primary production community. They are a desirable food source over other members of the primary production community through storage of photosynthetically produced sugars in the form of lipids rather than starch. Therefore, members of higher trophic levels selectively feed on diatoms when present with other members of the primary production community. This study examines the effects of select biogenically active compounds on the gross morphology and physiological development of the diatom species Cyclotella meneghiniana. Clearly, unicellular protists such as diatoms are not susceptible to these contaminants in a manner directly analogous to that expressed in vertebrates. However, many of these compounds are lipophilic making them particularly effective in entering the diatom cell membrane. Comparing cell density, lipid composition, fatty acid concentrations, and the electron microscope ultra‐structure in control and exposed cultures achieve this study's experimental objectives. This diatom was selected because it commonly occurs in most freshwater environments and has been the subject of other toxicological studies. An adequate literature base also exists for evaluating results of this experiment. The species grows rapidly and is easy to maintain in culture. The use of a phytoplankton species as a test organism complements other investigations involving vertebrate models at the apex of the trophic hierarchy by considering effects at the base of the food web.
Systemic Lupus Erythematosus Presenting as Subacute Delirium in an 82‐Year‐Old Woman
Authors: Heckman George A. , Papaioannou Alexandra , Adachi Jonathan D. , Denburg Judah A. 
Published: March 2003

OBJECTIVES: To describe an older patient with delirium attributed to systemic lupus erythematosus (SLE) and to review the literature on neuropsychiatric manifestations of SLE in older people.DESIGN: Case report and literature review. MEDLINE search using terms systemic lupus erythematosus, neurologic, psychiatric, neuropsychiatric, autoantibodies (antinuclear antibody (ANA), antiphospholipid, anticardiolipin, anti‐double stranded deoxyribonucleic acid (anti‐dsDNA), anti‐Smith), and elderly. Additional articles obtained from hand‐searched references and through experts.SETTING: Hospital (case report).PARTICIPANTS: Case report and literature cases.MEASUREMENTS: None.RESULTS: SLE is increasingly diagnosed in older adults. Onset is insidious and diagnosis is delayed because of a different clinical spectrum and immunological profile than in younger adults. Autoantibodies have an important role in the pathogenesis of neuropsychiatric manifestations, while vasculitis is less common. Aggressive immunosuppressive therapy is typically indicated, although recent case reports suggest that lower doses may suffice. The American College of Rheumatology 1982 revised criteria may be inadequate to diagnose neuropsychiatric lupus in older persons.CONCLUSION: Neuropsychiatric symptoms can be prominent in older people, presenting features of SLE. This case illustrates the lowest dose of corticosteroids shown to be effective in an older patient with delirium due to SLE.
Lipoprotein Metabolism in Japanese Centenarians: Effects of Apolipoprotein E Polymorphism and Nutritional Status
Authors: Arai Yasumichi , Hirose Nobuyoshi , Nakazawa Susumu , Yamamura Ken , Shimizu Ken‐ichirou , Takayama Michiyo , Ebihara Yoshinori , Osono Yasunori , Homma Satoki 
Published: March 2003

OBJECTIVES: To assess the complex interaction of apolipoprotein (apo) E polymorphisms and environmental factors on lipoprotein profile in centenarians.DESIGN: Cross‐sectional analysis.SETTING: Tokyo metropolitan area.PARTICIPANTS: Seventy‐five centenarians and 73 healthy older volunteers (mean age 63.1 ± 10.0) living in the Tokyo metropolitan area.MEASUREMENTS: Plasma lipids and lipoproteins, cholesteryl ester transfer protein mass, apo E phenotype, body mass index, nutritional indices (serum albumin, prealbumin, transferrin), dietary intake, inflammation markers (C‐reactive protein (CRP), interleukin‐6 (IL‐6)), activities of daily living, and cognitive function.RESULTS: In comparison with older people, the centenarians had low concentrations of total and low‐density lipoprotein cholesterol (LDL‐C) and a relative predominance of high‐density lipoprotein 2 cholesterol. No environmental factor, except the number of apo E ε2 alleles, was a significant determinant of LDL‐C and apo B, suggesting that the low apo B–containing lipoprotein in centenarians may be attributable to a genetic cause. Centenarians had elevated levels of lipoprotein (a) and decreased high‐density lipoprotein cholesterol (HDL‐C), which seem to be an unfavorable lipoprotein profile. Lower levels of HDL‐C in the centenarians were associated with decreased serum albumin, elevated CRP and IL‐6 levels, and cognitive impairment, suggesting that HDL‐C could be a sensitive marker for frailty and comorbidity in the oldest old.CONCLUSIONS: Low levels of apo B–containing lipoproteins attributable to a genetic cause may be advantageous for longevity. Lipoprotein profiles in centenarians were consistently related to the subjects' nutritional status, inflammation markers, and apo E polymorphisms. The results provide evidence for the importance of maintaining nutritional status in the very old.
Telomeres and Telomerase: Basic Science Implications for Aging
Authors: Ahmed Ali , Tollefsbol Trygve 
Published: March 2003

Life expectancy in the United States and other developed nations has increased remarkably over the past century, and continues to increase. However, lifespan has remained relatively unchanged over this period. As life expectancy approaches maximum human lifespan, further increase in life expectancy would only be possible if lifespan could also be increased. Although little is known about the aging process, increasing lifespan and delaying aging are the research challenges of the new century, and have caused intense debate and research activities among biogerontologists.Many theories have been proposed to explain the aging process. However, damage to deoxyribonucleic acid (DNA) is the centerpiece of most of these. Recently telomere shortening has been described to be associated with DNA damage. Located at the ends of eukaryotic chromosomes and synthesized by telomerase, telomeres maintain the length of chromosomes. The loss of telomeres can lead to DNA damage.The association between cellular senescence and telomere shortening in vitro is well established. In the laboratory, telomerase‐negative differentiated somatic cells maintain a youthful state, instead of aging, when transfected with vectors encoding telomerase. Many human cancer cells demonstrate high telomerase activity. Evidence is also accumulating that telomere shortening is associated with cellular senescence in vivo. What causes changes in expression of telomerase in different cell types and premature aging syndromes? Does the key to “youthfulness” lie in our ability to control the expression of telomerase? We have reviewed the contemporary literature to find answers to these questions and explore the association between aging, telomeres, and telomerase.
Age‐Related Determinants of Outcome After Acute Myocardial Infarction: A Dobutamine‐Atropine Stress Echocardiographic Study
Authors: Smart Steven , Sagar Kiran , Tresch Donald 
Published: March 2003

OBJECTIVES: To investigate the cause of worse survival in older patients after myocardial infarction (MI).DESIGN: Prospective 18‐month and longer follow‐up study of a cohort of 167 patients (mean age ± standard deviation 58 ± 12, including 71 aged ≥65) with acute MI for cardiac events, defined as cardiac death, recurrent MI, or resuscitated ventricular tachycardia or fibrillation (VT/VF).SETTING: Milwaukee County Medical Complex and the Zablocki Veterans Affairs Medical Center, Milwaukee, WI.PARTICIPANTS: One hundred sixty‐seven patients who underwent dobutamine‐atropine stress echocardiography (DASE) in the first week (2–7 days) after acute MI and were medically managed.MEASUREMENTS: Comparison of event rates in older (≥65 years) and younger (<65 years) patients and of clinical, resting echocardiographic, DASE, and angiographic findings in patients with and without events. Coronary angiography was performed in 141.RESULTS: Older and younger patients tolerated DASE well. During follow‐up, there were 29 cardiac events (cardiac death in 17, nonfatal MI in 10, and VT/VF in 2). Events were more common in older patients (26% vs 12%, P < .05), especially death (19% vs 5%, P < .05). Scar size in the infarct zone by DASE was larger (4.0 ± 2.8 vs 3.0 ± 2.7 segments, P < .05) and remote wall motion abnormalities more common (47 vs 29%, P < .05) in older patients. Univariate determinants of outcome (P < .05) in older patients were diabetes mellitus; remote wall motion abnormalities; angiographic multivessel disease; scar size; ejection fraction; and resting, low‐, and peak‐dose wall motion score. Univariate determinants in younger patients were similar, but diabetes mellitus was not. Multivariate analysis revealed that remote wall motion abnormalities and scar size by DASE were independently predictive of outcome in older and younger patients and diabetes mellitus only in older patients. Low‐ and peak‐dose DASE data enhanced (P < .01) the prediction of outcome in all patients with acute MI relative to clinical data and resting echocardiography.CONCLUSION: DASE was more predictive of outcome than clinical data and resting echocardiography in both age groups. Scar size and remote wall motion abnormalities were the primary determinants of outcome irrespective of age. The worse prognosis of older patients correlated with diabetes mellitus, greater scar size, and higher incidence of remote inducible ischemia.
Comparison of Mammography Use by Older Black and White Women
Authors: Han Beth , Wells Barbara L. , Primas Marion 
Published: March 2003

OBJECTIVES: To identify differences in the prevalence of ever having had a mammogram and having had a recent mammogram between older black and white women and to compare factors associated with mammography use in older black and white women.DESIGN: Data analysis and comparative study using nationally representative multistage sampling survey.SETTING: Data were obtained from the 1998 National Health Interview Survey.PARTICIPANTS: Four hundred forty‐nine black and 3,328 white older women were examined.MEASUREMENTS: The outcome variables included never having had a mammogram (yes/no) and not having had a mammogram in the past 3 years (yes/no).RESULTS: The results of chi‐square tests showed that older blacks were less likely to have ever had a mammogram than older whites, but there was no difference in having had a recent mammogram between older blacks and whites. After adjusting for other related factors, race was not related to mammography use in older blacks and whites. Health insurance was related to mammography use in older whites but not in older blacks. Family income was associated with never having had a mammogram in older whites but not in older blacks. Older blacks with less than 12 years of education were less likely to have had a mammogram (recently or ever) than older whites with less than 12 years of education.CONCLUSIONS: Even though race, per se, was not associated with mammography use in older black and white women, many barriers to mammography use between older black and white women were different or did not have similar effects. To promote mammography use in older black and white women, barriers need to be specifically targeted for each group to enhance the effectiveness of breast cancer screening programs.