Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 54
Filter
1.
Commun Biol ; 6(1): 1203, 2023 11 25.
Article in English | MEDLINE | ID: mdl-38007534

ABSTRACT

There are nearly 65 million people with chronic heart failure (CHF) globally, with no treatment directed at the pathologic cause of the disease, the loss of functioning cardiomyocytes. We have an allogeneic cardiac patch comprised of cardiomyocytes and human fibroblasts on a bioresorbable matrix. This patch increases blood flow to the damaged heart and improves left ventricular (LV) function in an immune competent rat model of ischemic CHF. After 6 months of treatment in an immune competent Yucatan mini swine ischemic CHF model, this patch restores LV contractility without constrictive physiology, partially reversing maladaptive LV and right ventricular remodeling, increases exercise tolerance, without inducing any cardiac arrhythmias or a change in myocardial oxygen consumption. Digital spatial profiling in mice with patch placement 3 weeks after a myocardial infarction shows that the patch induces a CD45pos immune cell response that results in an infiltration of dendritic cells and macrophages with high expression of macrophages polarization to the anti-inflammatory reparative M2 phenotype. Leveraging the host native immune system allows for the potential use of immunomodulatory therapies for treatment of chronic inflammatory diseases not limited to ischemic CHF.


Subject(s)
Heart Failure , Myocardial Infarction , Rats , Mice , Humans , Animals , Swine , Myocardial Infarction/pathology , Myocardial Infarction/therapy , Heart Failure/metabolism , Myocytes, Cardiac/metabolism , Ventricular Function, Left , Macrophages/metabolism
2.
Sci Rep ; 12(1): 13006, 2022 07 29.
Article in English | MEDLINE | ID: mdl-35906268

ABSTRACT

We report K-Pg-age deposits in Baja California, Mexico, consisting of terrestrial and shallow-marine materials re-sedimented onto the continental slope, including corals, gastropods, bivalves, shocked quartz grains, an andesitic tuff with a SHRIMP U-Pb age (66.12 ± 0.65 Ma) indistinguishable from that of the K-Pg boundary, and charred tree trunks. The overlying mudstones show an iridium anomaly and fungal and fern spores spikes. We interpret these heterogeneous deposits as a direct result of the Chicxulub impact and a mega-tsunami in response to seismically-induced landsliding. The tsunami backwash carried the megaflora offshore in high-density flows, remobilizing shallow-marine fauna and sediment en route. Charring of the trees at temperatures up to > 1000 °C took place in the interval between impact and arrival of the tsunami, which on the basis of seismic velocities and historic analogues amounted to only tens of minutes at most. This constrains the timing and causes of fires and the minimum distance from the impact site over which fires may be ignited.


Subject(s)
Fires , Landslides , Wildfires , Ecosystem , Mexico , Trees
3.
Radiography (Lond) ; 26 Suppl 2: S3-S7, 2020 10.
Article in English | MEDLINE | ID: mdl-32713823

ABSTRACT

Medical imaging is an ever changing field with significant advancements in techniques and technologies over the years. Despite being constantly challenged by change, it can be difficult to introduce changes into healthcare settings. In this article we introduce the principles of change management to achieve an evidence-based practice in radiography.


Subject(s)
Diagnostic Imaging , Evidence-Based Practice , Leadership , Humans , Radiography
4.
Radiography (Lond) ; 26 Suppl 2: S8-S13, 2020 10.
Article in English | MEDLINE | ID: mdl-32620353

ABSTRACT

Evidence-based healthcare is an approach to practice whereby decision making and service delivery considers the best available evidence, patient choice, local resources and clinical expertise. Although sound in theory, compliance with evidence-based practice is often far from optimal. To address this, related fields such as knowledge translation and implementation science have emerged, which largely focus on methods and techniques to facilitate the transfer of evidence into practice. This introductory article explains the key concepts of evidence-based healthcare by using the JBI Model as a framework to highlight the lifecycle of evidence-based information. Throughout the article we refer to exemplars from medical radiation to highlight these concepts.


Subject(s)
Evidence-Based Practice , Implementation Science , Translational Research, Biomedical , Humans , Radiography
5.
Am J Med Genet A ; 164A(5): 1085-91, 2014 May.
Article in English | MEDLINE | ID: mdl-24648351

ABSTRACT

The association between encephalocele and radial defects is considered uncommon. These features have been occasionally described separately in certain recurrent conditions such as VACTERL association, oculo-auriculo-vertebral spectrum and Edwards syndrome (trisomy 18). DK-phocomelia is a rare syndrome characterized by both findings. However, Froster-Iskenius and Meinecke [1992, Clin Dysmorphol 1: 37-41] and Kunze et al. [1992, Eur J Pediatr 151: 467-468] reported patients presenting similar malformations. We proposed, through the description of an additional case, that these last patients present the same condition and thus represent a new syndrome. The fetus presented a cranial vault deformity associated with an exuberant herniation of brain content, compatible with occipital encephalocele. Other uncommon features were also identified: microtia of the left ear with atresia of the external auditory canal; radial defect with aplasia of left radius and thumb; findings suggestive of a congenital heart defect and esophageal atresia; hypoplastic lungs and adrenals; thoracolumbar scoliosis; atrophic right kidney; and single umbilical artery. Thus, based on our review, we believe that these patients represent a new condition characterized by encephalocele and radial defects associated with multiple malformations. We propose, that the name "Encephalocele-radial, cardiac, gastrointestinal, anal/renal anomalies," as suggested by the London Medical Database, or even the name, "Froster-Iskenius and Meinecke syndrome" should be used to indicate these cases. © 2014 Wiley Periodicals, Inc.


Subject(s)
Abnormalities, Multiple/diagnosis , Phenotype , Adult , Anal Canal/abnormalities , Diagnosis, Differential , Esophagus/abnormalities , Female , Heart Defects, Congenital/diagnosis , Humans , Infant, Newborn , Kidney/abnormalities , Limb Deformities, Congenital/diagnosis , Pregnancy , Spine/abnormalities , Stillbirth , Syndrome , Trachea/abnormalities , Ultrasonography, Prenatal
6.
Int J Cardiol ; 167(1): 180-4, 2013 Jul 15.
Article in English | MEDLINE | ID: mdl-22240765

ABSTRACT

INTRODUCTION: There is conflicting evidence about the impact of gender on outcomes after coronary artery bypass grafting (CABG). METHODS: We performed a multivariate logistic regression and propensity score matched analyses in 13,115 patients (75% men) who underwent CABG between January 1, 1995 and December 31, 2009. The primary outcome was in-hospital mortality. Secondary outcomes included post-operative respiratory failure, stroke, myocardial infarction, sternal and leg wound infections, atrial fibrillation (AF), renal failure, need for postoperative intra-aortic balloon pump (IABP) support, and length of hospital stay. RESULTS: A higher proportion of women (184; 5.6%) suffered in-hospital death compared to men (264; 2.7%), p<0.0001. After propensity score matching (n=3600 total, 1800 in each group), female gender was an independent predictor of mortality after isolated CABG (odds ratio [OR]=1.84; 95% confidence interval [CI] 1.22-2.78). Women also experienced a higher incidence of postoperative complications including stroke (3.8% vs. 2.3%, OR 1.37; 95% CI 1.08-1.73) and leg wound infection (3.4% vs. 1.7%, OR 1.75; 95% CI 1.36-2.54) on multivariate regression analyses. However, these differences were not significant after propensity score matching. We also observed a lower risk of post-operative AF (21.2% vs. 22.1%, OR 0.78; 95% CI 0.70-0.86) in women that remained significant after propensity matching (O.R. 0.76; 95% C.I. 0.65-0.90). Length of hospital stay was longer in women compared with men (11.9 ± 9.0 vs. 10.4 ± 9.2 days, p<0.0001). CONCLUSIONS: Female gender is an independent predictor of increased mortality and a lower incidence of post-operative AF after isolated CABG.


Subject(s)
Coronary Artery Bypass/mortality , Hospital Mortality/trends , Postoperative Complications/mortality , Propensity Score , Sex Characteristics , Aged , Coronary Artery Bypass/trends , Female , Humans , Male , Middle Aged , Morbidity , Postoperative Complications/diagnosis , Retrospective Studies , Risk Factors
7.
Circ J ; 75(6): 1378-85, 2011.
Article in English | MEDLINE | ID: mdl-21498907

ABSTRACT

BACKGROUND: There is conflicting data regarding the impact of obesity on morbidity and mortality in patients undergoing isolated coronary artery bypass grafting (CABG). METHODS AND RESULTS: Retrospective cohort analysis of patients who underwent CABG from January 1, 1995, through July 31, 2010 was performed. Patients were classified as obese or non-obese (body mass index ≥ 30.0 kg/m(2) and <30.0 kg/m(2), respectively). The primary outcome was in-hospital mortality. Secondary outcomes included postoperative respiratory failure, postoperative stroke, postoperative myocardial infarction, sternal and leg wound infections, postoperative atrial fibrillation, postoperative ventricular tachycardia, postoperative renal failure and length of hospital stay. Propensity-matched stepwise multivariable logistic regression was performed. Of 13,115 patients, 4,619 (35.2%) were obese. In the propensity-matched logistic regression models (n = 8,442), obesity was not associated with postoperative mortality (odds ratio = 1.13, 95% confidence interval 0.86-1.48). However, obesity was associated with postoperative respiratory failure, postoperative renal insufficiency, sternal wound infection, and leg wound infection. Obesity was also associated with a decreased risk of postoperative bleeding and re-operation from bleeding. CONCLUSIONS: Obesity was associated with an increased risk of postoperative respiratory failure, postoperative renal failure, and surgical site infections. However, obesity was not associated with in-hospital mortality in patients undergoing CABG.


Subject(s)
Coronary Artery Bypass , Coronary Artery Disease/surgery , Obesity/complications , Aged , Coronary Artery Bypass/adverse effects , Coronary Artery Bypass/mortality , Coronary Artery Disease/complications , Coronary Artery Disease/mortality , Female , Hospital Mortality , Humans , Logistic Models , Male , Middle Aged , Obesity/mortality , Odds Ratio , Postoperative Hemorrhage/etiology , Propensity Score , Renal Insufficiency/etiology , Respiratory Insufficiency/etiology , Retrospective Studies , Risk Assessment , Risk Factors , Surgical Wound Infection/etiology , Texas , Time Factors , Treatment Outcome
8.
Mol Biochem Parasitol ; 175(2): 169-80, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21075147

ABSTRACT

Proteolytic activity is important in the lifecycles of parasites and their interactions with hosts. Cysteine proteases have been best studied in Giardia, but other protease classes have been implicated in growth and/or differentiation. In this study, we employed bioinformatics to reveal the complete set of putative proteases in the Giardia genome. We identified 73 peptidase homologs distributed over 5 catalytic classes in the genome. Serial analysis of gene expression of the G. lamblia lifecycle found thirteen protease genes with significant transcriptional variation over the lifecycle, with only one serine protease transcript upregulated late in encystation. The translated gene sequence of this encystation-specific transcript was most similar to eukaryotic subtilisin-like proprotein convertases (SPC), although the typical catalytic triad was not identified. Epitope-tagged gSPC protein expressed in Giardia under its own promoter was upregulated during encystation with highest expression in cysts and it localized to encystation-specific secretory vesicles (ESV). Total gSPC from encysting cells produced proteolysis in gelatin gels that co-migrated with the epitope-tagged protease in immunoblots. Immuno-purified gSPC also had gelatinase activity. To test whether endogenous gSPC activity is involved in differentiation, trophozoites and cysts were exposed to the specific serine proteinase inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride (AEBSF). After 21 h encystation, a significant decrease in ESV was observed with 1mM AEBSF and by 42 h the number of cysts was significantly reduced, but trophozoite growth was not inhibited. Concurrently, levels of cyst wall proteins 1 and 2, and AU1-tagged gSPC protein itself were decreased. Excystation of G. muris cysts was also significantly reduced in the presence of AEBSF. These results support the idea that serine protease activity is essential for Giardia encystation and excystation.


Subject(s)
Giardia lamblia/enzymology , Giardia lamblia/growth & development , Proprotein Convertases/genetics , Proprotein Convertases/metabolism , Amino Acid Sequence , Computational Biology/methods , Electrophoresis , Gelatin/metabolism , Gene Expression Profiling , Giardia lamblia/genetics , Immunoblotting , Microscopy, Confocal , Microscopy, Fluorescence , Molecular Sequence Data , Protein Structure, Tertiary , Secretory Vesicles/chemistry
9.
Parasitology ; 136(5): 469-85, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19265565

ABSTRACT

SUMMARY: Infection of the snail, Biomphalaria glabrata, by the free-swimming miracidial stage of the human blood fluke, Schistosoma mansoni, and its subsequent development to the parasitic sporocyst stage is critical to establishment of viable infections and continued human transmission. We performed a genome-wide expression analysis of the S. mansoni miracidia and developing sporocyst using Long Serial Analysis of Gene Expression (LongSAGE). Five cDNA libraries were constructed from miracidia and in vitro cultured 6- and 20-day-old sporocysts maintained in sporocyst medium (SM) or in SM conditioned by previous cultivation with cells of the B. glabrata embryonic (Bge) cell line. We generated 21 440 SAGE tags and mapped 13 381 to the S. mansoni gene predictions (v4.0e) either by estimating theoretical 3' UTR lengths or using existing 3' EST sequence data. Overall, 432 transcripts were found to be differentially expressed amongst all 5 libraries. In total, 172 tags were differentially expressed between miracidia and 6-day conditioned sporocysts and 152 were differentially expressed between miracidia and 6-day unconditioned sporocysts. In addition, 53 and 45 tags, respectively, were differentially expressed in 6-day and 20-day cultured sporocysts, due to the effects of exposure to Bge cell-conditioned medium.


Subject(s)
Gene Expression Profiling , Gene Expression Regulation, Developmental , Helminth Proteins/metabolism , Schistosoma mansoni/growth & development , Animals , Base Sequence , Biomphalaria/parasitology , DNA, Helminth/analysis , Gene Library , Helminth Proteins/genetics , Host-Parasite Interactions , Larva/genetics , Larva/growth & development , Larva/metabolism , Molecular Sequence Data , Oocysts/growth & development , Oocysts/metabolism , Schistosoma mansoni/genetics , Schistosoma mansoni/metabolism , Sequence Analysis, DNA
10.
Rural Remote Health ; 7(2): 630, 2007.
Article in English | MEDLINE | ID: mdl-17508838

ABSTRACT

INTRODUCTION: As part of its health system reconstruction following decades of civil war, Cambodia undertook a program of health sector reform in 1996 to expand coverage of essential health services to the population of 14 million, 80% of whom are resident in over 13 000 rural villages. During this reform period, one of the major national health programs, the National Immunization Program (NIP), adapted its planning system to accommodate changes in social and health sector structure. AIMS: The aims of this article are to review changes made in the approach to national immunization planning and to illustrate how these adaptations can help identify future challenges and opportunities for further improving immunization coverage in Cambodia. Sources of information for the study include immunization plans and data from international and national sources, as well as data from the national health information system. Findings of review: Management and service delivery reforms undertaken by the NIP include (1) strengthening links between immunization, health sector and international health planning; (2) development of immunization program multiyear and financial sustainability plans; (3) strengthening of national program decision making structures and processes; (4) widening of decentralized stakeholder participation in health planning; and (5) implementation of service level micro-planning. OUTCOMES: These management reforms have been associated with significant improvement in public health program performance and outcomes during this period (2003-2006). There has been an increase in vaccination coverage for children under the age of one year, over a five-year period (increase of 29% for fully immunized child at one year of age), with no significant differences in vaccination rates between urban and rural areas, and a sharp decrease in the incidence of vaccine preventable diseases. CONCLUSION: The NIP is now well positioned to take on additional challenges in coming years associated with expanding international partnerships, the continued development of civil society, further health system decentralization, and the requirement to further improve coverage in support of global and regional disease elimination goals. However, as costs continue to rise, planners in the future will need to emphasize the economic and public health benefits of immunization programs in order to sustain increasing levels of national and international investment.


Subject(s)
Health Planning/methods , Immunization Programs/organization & administration , National Health Programs/organization & administration , Organizational Culture , Cambodia , Decision Making , Financing, Government , Health Care Reform/methods , Humans , Infant
11.
Int J Antimicrob Agents ; 23(5): 506-9, 2004 May.
Article in English | MEDLINE | ID: mdl-15120732

ABSTRACT

Management of urinary tract infections (UTI) in Central America and especially Nicaragua, is complicated by the lack of knowledge about the antibiotic resistance of uropathogens. We conducted a prevalence study to gain more insight into the aetiology, bacterial resistance and risk factors for symptomatic UTI in the region of León, Nicaragua. In 2002, all consecutive patients with UTI symptoms and pyuria >/=10 WBC/hpf were admitted to the study. Positive cultures from midstream urine specimens were defined as >/=10(5) cfu/ml of a single uropathogen. Susceptibility tests were performed with disc diffusion tests using the Kirby-Bauer method and broth microdilution using National Committee for Clinical Laboratory Standards criteria both in León and a reference laboratory in Utrecht. A positive culture was present in 62 of 208 study subjects (30%). Escherichia coli (56%), Klebsiella spp. (18%) and Enterobacter spp. (11%) were the most frequent pathogens isolated. Presence of cystocele, incontinence and increasing age were risk factors for bacterial UTI. E. coli was least resistant to ceftriaxone, amikacin and nitrofurantoin (>90% susceptible). We observed high resistance rates in E. coli to amoxicillin (82%, MIC(90) 128 mg/l), trimethoprim-sulphamethoxazole (TMP-SMX) (64%, MIC(90) 32 mg/l), cephalothin (58%, MIC(90), 32 mg/l), ciprofloxacin (30%; MIC(90), 32 mg/l), amoxicillin/clavulanate (21%, MIC(90) 8 mg/l) and gentamicin (12%, MIC(90) 2 mg/l). Our results suggests that community acquired uropathogens in Nicaragua are highly resistant to many antimicrobial agents. The use of amoxicillin, trimethoprim-sulphamethoxazole and cephalothin against uropathogens needs to be reconsidered. High quinolone resistance rates among E. coli in Nicaragua gives cause for great concern.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Bacteria/isolation & purification , Urinary Tract Infections/microbiology , Adult , Amoxicillin/pharmacology , Amoxicillin/therapeutic use , Cephalothin/pharmacology , Cephalothin/therapeutic use , Drug Combinations , Drug Resistance, Bacterial , Enterobacter/drug effects , Enterobacter/isolation & purification , Escherichia coli/drug effects , Escherichia coli/isolation & purification , Female , Humans , Klebsiella/drug effects , Klebsiella/isolation & purification , Male , Microbial Sensitivity Tests , Nicaragua , Pyuria/microbiology , Quinolones/pharmacology , Quinolones/therapeutic use , Risk Factors , Sulfamethizole/pharmacology , Sulfamethizole/therapeutic use , Trimethoprim/pharmacology , Trimethoprim/therapeutic use , Urinary Bladder Diseases , Urinary Incontinence , Urinary Tract Infections/drug therapy , Urinary Tract Infections/epidemiology , Urine/microbiology
12.
Arch Biochem Biophys ; 410(2): 238-45, 2003 Feb 15.
Article in English | MEDLINE | ID: mdl-12573283

ABSTRACT

We have characterized a cold-induced, boiling stable antifreeze protein. This highly active ice recrystallization inhibition protein shows a much lower thermal hysteresis effect and displays binding behavior that is uncharacteristic of any AFP from fish or insects. Ice-binding studies show it binds to the (1 0 1 0) plane of ice and FTIR studies reveal that it has an unusual type of highly beta-sheeted secondary structure. Ice-binding studies of both glycosylated and nonglycosylated expressed forms indicate that it adsorbs to ice through the protein backbone. These results are discussed in light of the currently proposed mechanisms of AFP action.


Subject(s)
Antifreeze Proteins/chemistry , Lolium/metabolism , Peptides/chemistry , Animals , Antifreeze Proteins/metabolism , Binding Sites , Electrophoresis, Polyacrylamide Gel , Escherichia coli/metabolism , Fishes , Hot Temperature , Ice , Protein Structure, Secondary , Protein Structure, Tertiary , Spectroscopy, Fourier Transform Infrared , Temperature
13.
Mol Biol Evol ; 18(8): 1455-63, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11470836

ABSTRACT

A phylogenetic analysis of protein disulfide isomerase (PDI) domain evolution was performed with the inclusion of recently reported PDIs from the amitochondriate protist Giardia lamblia, yeast PDIs that contain a single thioredoxin-like domain, and PDIs from a diverse selection of protists. We additionally report and include two new giardial PDIs, each with a single thioredoxin-like domain. Inclusion of protist PDIs in our analyses revealed that the evolutionary history of the endoplasmic reticulum may not be simple. Phylogenetic analyses support common ancestry of all eukaryotic PDIs from a thioredoxin ancestor and independent duplications of thioredoxin-like domains within PDIs throughout eukaryote evolution. This was particularly evident for Acanthamoeba PDI, Dictyostelium PDI, and mammalian erp5 domains. In contrast, gene duplication, instead of domain duplication, produces PDI diversity in G. lamblia. Based on our results and the known diversity of PDIs, we present a new hypothesis that the five single-domain PDIs of G. lamblia may reflect an ancestral mechanism of protein folding in the eukaryotic endoplasmic reticulum. The PDI complement of G. lamblia and yeast suggests that a combination of PDIs may be used as a redox chain analogous to that known for bacterial Dsb proteins.


Subject(s)
Evolution, Molecular , Giardia lamblia/genetics , Protein Disulfide-Isomerases/genetics , Amino Acid Sequence , Animals , Binding Sites/genetics , DNA, Protozoan/chemistry , DNA, Protozoan/genetics , Molecular Sequence Data , Phylogeny , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid
14.
Article in English | MEDLINE | ID: mdl-11174594

ABSTRACT

BACKGROUND: The protein c-erb B-2, also known as Her2/neu, is a prognostic breast cancer marker assayed in tissue biopsy specimens from women diagnosed with malignant tumors. Current studies suggest that soluble fragments of the c-erb B-2 oncogene may be released from the cell surface and become detectable in patients with a carcinoma of the breast. Consequently, the purpose of this study is to assay soluble c-erb B-2 protein in the saliva of healthy men and women to determine the reliability of the assay. METHODS: To determine the diagnostic utility of this oncogene, we assayed the soluble form of the c-erb B-2 protein in the saliva with an enzyme-linked immunosorbent assay. The study population consisted of 10 healthy women and 9 healthy men who were serially sampled for saliva 3 times a day for a 5-day period. Saliva was collected from each subject at 9 AM, 4 PM, and 9 PM during the 5-day period. RESULTS: We found the presence of c-erb B-2 protein in the saliva of both groups of subjects. The salivary levels of c-erb B-2 were not significantly different when compared for gender differences. Likewise, the results suggest that sampling during various times of the day for salivary c-erb B-2 levels has no effect on marker concentration. Reliability analyses showed that supervised salivary collections were more reliable than unsupervised collections. CONCLUSIONS: The results of this pilot study suggest that the assay for salivary c-erb B-2 protein is reliable and might have potential use in the initial detection and follow-up screening for the recurrence of breast cancer in both men and women.


Subject(s)
Receptor, ErbB-2/analysis , Saliva/chemistry , Salivary Proteins and Peptides/analysis , Adult , Biomarkers, Tumor/analysis , Circadian Rhythm , Confidence Intervals , Enzyme-Linked Immunosorbent Assay , Female , Humans , Linear Models , Male , Pilot Projects , Reproducibility of Results , Sex Factors , Specimen Handling
15.
J Mol Evol ; 51(3): 278-85, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11029072

ABSTRACT

Molecular and morphological evidence points to the ancyromonad Ancyromonas as a plausible candidate for the closest relative to the common ancestor of metazoans, fungi, and choanoflagellates (the Opisthokonta). Using 18S rDNA sequences from most of the major eukaryotic lineages, maximum-likelihood, minimum-evolution, and maximum-parsimony analyses yielded congruent phylogenies supporting this hypothesis. Combined with ultrastructural similarities between Ancyromonas and opisthokonts, the evidence presented here suggests that Ancyromonas may form an independent lineage, the Ancyromonadida Cavalier-Smith 1997, closer in its relationship to the opisthokonts than is its nearest protist relatives, the Apusomonadida. However, the very low bootstrap support for deep nodes and hypothesis testing indicate that the resolving power of 18S rDNA sequences is limited for examining this aspect of eukaryotic phylogeny. Alternate branching positions for the Ancyromonas lineage cannot be robustly rejected, revealing the importance of ultrastructure when examining the origins of multicellularity. The future use of a multigene approach may additionally be needed to resolve this aspect of eukaryotic phylogeny.


Subject(s)
Eukaryota/classification , Eukaryota/genetics , Phylogeny , Animals , Base Sequence , DNA Primers/genetics , DNA, Fungal/genetics , DNA, Protozoan/genetics , DNA, Ribosomal/genetics , Eukaryota/ultrastructure , Evolution, Molecular , Fungi/classification , Fungi/genetics , Likelihood Functions , Microscopy, Electron, Scanning , Models, Genetic
16.
FEMS Microbiol Lett ; 189(2): 271-3, 2000 Aug 15.
Article in English | MEDLINE | ID: mdl-10930750

ABSTRACT

The Giardia genome project database provides an online resource for Giardia lamblia (WB strain, clone C6) genome sequence information. The database includes edited single-pass reads, the results of BLASTX searches, and details of progress towards sequencing the entire 12 million-bp Giardia genome. Pre-sorted BLASTX results can be retrieved based on keyword searches and BLAST searches of the high throughput Giardia data can be initiated from the web site or through NCBI. Descriptions of the genomic DNA libraries, project protocols and summary statistics are also available. Although the Giardia genome project is ongoing, new sequences are made available on a bi-monthly basis to ensure that researchers have access to information that may assist them in the search for genes and their biological function. The current URL of the Giardia genome project database is www.mbl.edu/Giardia.


Subject(s)
Databases, Factual , Genome, Protozoan , Giardia/genetics , Animals
18.
Mol Biol Evol ; 17(8): 1156-63, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10908635

ABSTRACT

Genes coding for the core histones H2a, H2b, H3, and H4 of Giardia lamblia were sequenced. A conserved organism- and gene-specific element, GRGCGCAGATTTVGG, was found upstream of the coding region in all core histone genes. The derived amino acid sequences of all four histones were similar to their homologs in other eukaryotes, although they were among the most divergent members of this protein family. Comparative protein structure modeling combined with energy evaluation of the resulting models indicated that the G. lamblia core histones individually and together can assume the same three-dimensional structures that were established by X-ray crystallography for Xenopus laevis histones and the nucleosome core particle. Since G. lamblia represents one of the earliest-diverging eukaryotes in many different molecular trees, the structure of its histones is potentially of relevance to understanding histone evolution. The G. lamblia proteins do not represent an intermediate stage between archaeal and eukaryotic histones.


Subject(s)
Giardia/genetics , Histones/genetics , Amino Acid Motifs , Amino Acid Sequence , Animals , Base Sequence , Conserved Sequence , DNA, Protozoan/chemistry , DNA, Protozoan/genetics , Histones/chemistry , Models, Molecular , Molecular Sequence Data , Molecular Structure , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid
19.
J Neurosci ; 20(14): 5496-502, 2000 Jul 15.
Article in English | MEDLINE | ID: mdl-10884333

ABSTRACT

The main mammalian circadian pacemaker is located in the suprachiasmatic nuclei (SCN) of the hypothalamus. Gastrin-releasing peptide (GRP) and its receptor (BB(2)) are synthesized by rodent SCN neurons, but the role of GRP in circadian rhythm processes is unknown. In this study, we examined the phase-resetting actions of GRP on the electrical activity rhythms of hamster and rat SCN neurons in vitro. In both rat and hamster SCN slices, GRP treatment during the day did not alter the time of peak SCN firing. In contrast, GRP application early in the subjective night phase-delayed, whereas similar treatment later in the subjective night phase-advanced the firing rate rhythm in rat and hamster SCN slices. These phase shifts were completely blocked by the selective BB(2) receptor antagonist, [d-Phe(6), Des-Met(14)]-bombesin 6-14 ethylamide. We also investigated the temporal changes in the expression of genes for the BB(1) and BB(2) receptors in the rat SCN using a quantitative competitive RT-PCR protocol. The expression of the genes for both receptors was easily detected, but their expression did not vary over the diurnal cycle. These data show that GRP phase-dependently phase resets the rodent SCN circadian pacemaker in vitro apparently via the BB(2) receptor. Because this pattern of phase shifting resembles that of light on rodent behavioral rhythms, these results support the contention that GRP participates in the photic entrainment of the rodent SCN circadian pacemaker.


Subject(s)
Bombesin/analogs & derivatives , Circadian Rhythm/physiology , Gastrin-Releasing Peptide/metabolism , Neurons/metabolism , Suprachiasmatic Nucleus/metabolism , Analysis of Variance , Animals , Biological Clocks/drug effects , Bombesin/pharmacology , Circadian Rhythm/drug effects , Cricetinae , Darkness , Dose-Response Relationship, Drug , Drug Administration Schedule , Gastrin-Releasing Peptide/administration & dosage , In Vitro Techniques , Male , Mesocricetus , Neurons/cytology , Neurons/drug effects , Peptide Fragments/pharmacology , Photoperiod , RNA, Messenger/analysis , Rats , Rats, Wistar , Receptors, Bombesin/antagonists & inhibitors , Receptors, Bombesin/biosynthesis , Receptors, Bombesin/genetics , Reverse Transcriptase Polymerase Chain Reaction , Suprachiasmatic Nucleus/cytology , Suprachiasmatic Nucleus/drug effects
20.
Mol Phylogenet Evol ; 13(2): 255-74, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10603255

ABSTRACT

A molecular phylogenetic investigation of the hypothesized antiquity of the hydrothermal vent endemic Neomphalina (Mollusca; Gastropoda) is reported. Sequences of two domains of the gene encoding for 28S ribosomal RNA were acquired for 3 outgroup and 32 gastropod genera. Use of the likelihood ratio test indicated complex substitution patterns for these domains and taxa, corresponding to a general time-reversible model with among-site rate variation. Phylogenetic analyses were performed using this model under maximum likelihood criteria. The data lacked resolution of gastropod radiations of the Paleozoic and all three of the outgroup sequences were randomized relative to the ingroup. Acceleration of evolutionary rates had additionally randomized the sequences of the Patellogastropoda relative to the other Gastropoda. The data resolved radiations of the Mesozoic and supported monophyly of the sampled Neritopsina, Vetigastropoda, Neomphalina, Caenogastropoda (including Campanile and the Architaenioglossa), and Heterobranchia (Valvata + Euthyneura), although several results were not significantly different from nonmonophyletic alternatives. Mesozoic origins of the hydrothermal vent endemic Neomphalina are preliminarily supported and implications for the hydrothermal vent refugia hypothesis discussed. Issues related to phylogenetic resolution of the Gastropoda are additionally discussed.


Subject(s)
Mollusca/genetics , Phylogeny , RNA, Ribosomal, 28S/genetics , Animals , Base Sequence , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Evolution, Molecular , Molecular Sequence Data , Mollusca/classification , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid
SELECTION OF CITATIONS
SEARCH DETAIL
...