Trans fatty acids and dieting.
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Coronary Disease↗
Biomedical subjects
D Jones
Publications and source records attributed to D Jones.
Utilization of transferrin-bound iron by Listeria monocytogenes.
It has been demonstrated that under iron-restricted conditions, Listeria monocytogenes can utilize iron-loaded transferrin (Tf) from a range of species as its sole source of iron for growth. Human transferrin conjugated to horseradish-peroxidase (HRP-Tf) bound directly to whole cells of L. monocytogenes. This binding was blocked by apotransferrin indicating that the receptor can bind transferrin in either the iron-bound or iron-free form. Transferrin-binding was not host specific because both bovine and equine transferrin inhibited the binding of HRP-conjugated human transferrin. SDS-PAGE and Western blotting of bacterial surface extracts revealed the presence of a transferrin-binding protein of approximately 126 kDa.
Animals↗
More protein talk.
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Amino Acid Sequence↗
Predicted values for peak flow rates.
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Adult↗
Specification of variability in positioning.
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Humans↗
Expression of a parasitism-specific protein in lepidopteran hosts of Chelonus sp.
The hemolymph of each noctuid species successfully parasitized by Chelonus near curvimaculatus possessed a parasitism-specific protein (PSP) previously identified in host T. ni (Insect Biochem. 19:445;21:845). Expression of PSP occurred in a stage-specific manner in the stadium during which the host undergoes precocious metamorphosis. The appearance of the protein was not due to nutritional stress associated with parasitism of hosts, since starved nonparasitized larvae did not produce the protein, or to low juvenile hormone titers occurring in precociously metamorphosing hosts, but rather was dependent on the presence of the endoparasite larva. Results of an in vivo incorporation experiments with [35S]-methionine showed that synthesis and subsequent appearance of the protein in the hemolymph of parasitized hosts was abrogated by prior surgical removal of endoparasite. Immunoprecipitation analysis of proteins from C. near curvimaculatus larvae cultured in vitro using antibodies specific to PSP indicated that the source of the protein was the endoparasite. Synthesis of PSP by the endoparasitic larvae with its subsequent secretion into the hemocoel of hosts was specific to the advanced stages of parasite development prior to its regression from the host.
Animals↗
Liver resection with normothermic ischaemia exceeding 1 h.
A retrospective study was made of 34 patients who underwent major liver resection with a single period of vascular occlusion exceeding 60 min. The liver remnant was normal in all cases. Vascular occlusion was achieved by continuous portal triad clamping (15 patients), hepatic vascular exclusion (15) or a sequential combination of both procedures (four). Liver cooling was not used. The mean (s.e.m.) duration of continuous normothermic liver ischaemia was 73.6 (2.5) (range 60-127) min. The mean (s.e.m.) amount of blood transfused during operation was 5.3(0.8) units packed red cells. There were no deaths after surgery and the postoperative course was uneventful, or limited to asymptomatic pleural effusion, in 18 patients. Three patients suffered postoperative bleeding necessitating further surgery and one of these required reintervention for a prolonged bile leak. Four patients had transient liver failure that resolved spontaneously within 15 days. There was a 13-fold increase in serum transaminase activities and the proaccelerin level was 45 per cent that of normal on day 1 after operation. These changes were returning to normal levels within 15 days. Continuous vascular occlusion during major liver resection is a useful manoeuvre that may be performed safely on normal hepatic parenchyma for up to 90 min.
Adult↗
Antitermination of amidase expression in Pseudomonas aeruginosa is controlled by a novel cytoplasmic amide-binding protein.
Amide-inducible expression of the aliphatic amidase system of Pseudomonas aeruginosa can be reconstituted in Escherichia coli with only the amidase structural gene amiE, the negative regulator amiC and the positive regulator amiR, a transcription antitermination factor. Complementation experiments in E. coli suggest that negative control of amidase expression by AmiC is mediated by a protein-protein interaction with AmiR. Purified AmiC binds acetamide with a KD of 3.7 microM in equilibrium dialysis studies, and therefore AmiC appears to be the sensory partner of the AmiC/AmiR pair of regulatory proteins, responding to the presence of amides. Sequence analysis techniques suggest that AmiC is a member of the structural family of periplasmic binding proteins, but has a distinct and novel cytoplasmic role.
Amidohydrolases↗
Recombinant human erythropoietin (rHuEPO) for treatment of myelodysplastic syndrome.
Sixteen patients (ages 53 to 85) with myelodysplastic syndrome (MDS) were treated with recombinant human erythropoietin (rHuEPO) to observe its effects on hematopoiesis. All were transfusion dependent and had Hb levels less than 9.0 g/dl and less than 10% marrow blasts. Eight patients had refractory anemia (RA), one had refractory anemia with excess blasts (RAEB), and seven had refractory anemia with ringed sideroblasts (RARS). A response was defined as an increase in Hb by greater than 2 g/dl and/or a decrease in transfusion requirement by greater than 50%. Patients were considered to be evaluable if on study greater than two months. Three of thirteen evaluable patients had a response. One patient with RA had a sustained trilineage hematologic response with no evidence of disease progression. None of the patients had trouble with hypertension or with thrombotic events. This suggests than an occasional patient with MDS will respond to rHuEPO. In some patients, this may be beneficial clinically.
Aged↗
Isolation and sequencing of deer and sheep insulin-like growth factors-I and -II.
We have developed a simple method for the isolation of highly purified cervine (c) and ovine (o) insulin-like growth factors-I (IGF-I) and -II. The IGFs were isolated from acidified serum by cation exchange chromatography and then purified by gel filtration, chromatofocusing, and reverse-phase chromatography. The IGF preparations are > 95% pure. The cIGF-I preparation contains < 0.056% cIGF-II and the oIGF-I preparation contains < 0.01% oIGF-II. Both the IGF-II preparations contain < 0.01% IGF-I. The amino acid sequence of cIGF-I has two differences when compared with human (h) IGF-I. The cIGF-II sequence, which is identical to bovine IGF-II, has three differences when compared with hIGF-II.
Amino Acid Sequence↗
Retrovirus insertion into herpesvirus: characterization of a Marek's disease virus harboring a solo LTR.
We recently reported the phenomenon of retroviral insertion into a herpesvirus (Isfort et al., (1992) Proc. Natl. Acad. Sci. USA 89, 991-995). We have now isolated Marek's disease virus (MDV) clones that carry retroviral inserts. Retroviral LTR insertion has the potential to activate or inactivate herpesvirus genes leading to alterations of the biological properties of the herpesviruses. The structure and the expression pattern of a virus clone carrying a solitary LTR insertion was characterized in detail. The LTR insertion is accompanied by deletions in the herpesvirus genome at each of the junctions of the short unique region (US) and its inverted repeats (RS). This results in a significantly truncated RS region. Despite these structural rearrangements, the virus is replication-competent and demonstrates an enhanced growth rate in vitro. While the MDV homologs of herpes simplex US genes are retained in this virus, at least two open reading frames are deleted and one transcript observed in wild-type virus is disrupted. In addition to defining several regions of MDV that are nonessential for in vitro growth, this clone illustrates one way in which retroviral information can be stably transmitted by a herpesvirus.
Animals↗
Renal amino acid transport: cellular and molecular events from clearance studies to frog eggs.
This article reviews recent advances in the mechanisms of renal amino acid transport. Renal amino acid transport is necessary to efficiently reclaim approximately 450 mmol amino acids from the glomerular ultrafiltrate each day in man. In general, individual amino acids are transported across the epithelial membrane of the proximal tubule by a sodium (Na+) dependent mechanism. This cotransport process utilizes the energy of the Na+ gradient to enter the cell. The amino acid then exits the basolateral surface and Na+ is pumped out by the Na(+)-K(+)-ATPase located in the basolateral membrane. In addition to the cellular accumulation of amino acids across the luminal membrane, these compounds may be taken up by the cell from the basolateral surface. Most amino acids are transported both individually and in a series of seven group specific processes. Human disorders of amino acid transport have been described for six of the seven transport systems. The process of ontogeny of amino acid accumulation by the proximal tubule is a complex one and will be further discussed in this review. A number of factors including pH, ion dependency, electrogenicity of transport process, as well as a variety of hormonal factors, may contribute to the regulation of amino acid transport. Gene expression of several amino acid transporters has been successfully performed using the oocyte of the frog Xenopus laevis. Using this system, a number of transporters have been cloned. Such a strategy will permit the cloning of virtually all transporter molecules, and thus we can anticipate the elucidation of the structure of the transporters. However, for a comprehensive understanding of cytoskeletal interactions protein phosphorylation and phospholipid domains and their linkage to the primary structure of the transporter need to be studied. The future for research in this area is indeed a bright one.
Amino Acid Metabolism, Inborn Errors↗
Protein fold recognition.
An important, yet seemingly unattainable, goal in structural molecular biology is to be able to predict the native three-dimensional structure of a protein entirely from its amino acid sequence. Prediction methods based on rigorous energy calculations have not yet been successful, and best results have been obtained from homology modelling and statistical secondary structure prediction. Homology modelling is limited to cases where significant sequence similarity is shared between a protein of known structure and the unknown. Secondary structure prediction methods are not only unreliable, but also do not offer any obvious route to the full tertiary structure. Recently, methods have been developed whereby entire protein folds are recognized from sequence, even where little or no sequence similarity is shared between the proteins under consideration. In this paper we review the current methods, including our own, and in particular offer a historical background to their development. In addition, we also discuss the future of these methods and outline the developments under investigation in our laboratory.
Amino Acid Sequence↗
Depressed affect, hopelessness, and the risk of ischemic heart disease in a cohort of U.S. adults.
Major depression has been associated with mortality from ischemic heart disease (IHD). In addition, a symptom of depression--hopelessness--has been suggested as a determinant of health status. We studied the relation of both depressed affect and hopelessness to IHD incidence using data from a cohort of 2,832 U.S. adults age 45-77 years who participated in the National Health Examination Follow-up Study (mean follow-up = 12.4 years) and had no history of IHD or serious illness at baseline. We used the depression subscale of the General Well-Being Schedule to define depressed affect and a single item from the scale to define hopelessness. At baseline, 11.1% of the cohort had depressed affect; 10.8% reported moderate hopelessness, and 2.9% reported severe hopelessness. Depressed affect and hopelessness were more common among women, blacks, and persons who were less educated, unmarried, smokers, or physically inactive. There were 189 cases of fatal IHD during the follow-up period. After we adjusted for demographic and risk factors, depressed affect was related to fatal IHD [relative risk = 1.5; 95% confidence interval (CI) = 1.0-2.3]; the relative risks of fatal IHD for moderate and severe levels of hopelessness were 1.6 (95% CI = 1.0-2.5) and 2.1 (95% CI = 1.1-3.9), respectively. Depressed affect and hopelessness were also associated with an increased risk of nonfatal IHD. These data indicate that depressed affect and hopelessness may play a causal role in the occurrence of both fatal and nonfatal IHD.
Aged↗
The use of resonant frequency measurements for the noninvasive assessment of mechanical stiffness of the healing tibia.
A study was performed to assess the usefulness of measuring the resonant frequency of vibration of the tibia as a determinant of its flexural rigidity in fracture healing. The measurement system consisted of an electronic tapper that struck the anteromedial distal surface of the tibia and an accelerometer, held against the proximal surface, that received the response. Custom software displayed the frequency spectrum from which the first mode bending frequency of the tibia could be pinpointed. We have found that resonant frequency was highly correlated to the log of tibial flexural rigidity, with an exponent of 0.582 (r2 = 0.815). In human volunteers, a series of four tests at monthly intervals showed a reproducibility of approximately 3% (95% confidence interval) with no significant variability between right and left legs. In 14 patients with healing tibial fractures, resonant frequency ratio (healing/injured leg) was correlated to time ratio (time of test/time healed) by a second-order polynomial fit (r2 = 0.58).
Adolescent↗
Characterization of an aromatic amino acid-dependent Listeria monocytogenes mutant: attenuation, persistence, and ability to induce protective immunity in mice.
A transposon insertion mutant of Listeria monocytogenes was shown to be deficient in prephenate dehydratase, an enzyme acting late in the pathway for biosynthesis of phenylalanine. This mutant had reduced virulence in mice. The mutant and parent strains persisted to the same extent in the tissues of infected mice and elicited similar degrees of splenomegaly. Mice vaccinated with the mutant were protected significantly from subsequent challenge with virulent L. monocytogenes.
Animals↗
Enzyme-linked immunosorbent assay for detection of human immunoglobulin G to lipopolysaccharide of spotted fever group rickettsiae.
An enzyme-linked immunosorbent assay for detecting human immunoglobulin G to spotted fever group rickettsiae was developed and tested. The assay uses proteinase K-resistant material, characteristic of the rickettsial lipopolysaccharides shown to be group specific by immunoblots, as the antigen. The results indicate that the assay provides a sensitive, yet specific, alternative method for diagnosing rickettsial diseases.
Endopeptidase K↗
The ubc-2 gene of Caenorhabditis elegans encodes a ubiquitin-conjugating enzyme involved in selective protein degradation.
The ubiquitin-protein conjugation system is involved in a variety of eukaryotic cell functions, including the degradation of abnormal and short-lived proteins, chromatin structure, cell cycle progression, and DNA repair. The ubiquitination of target proteins is catalyzed by a ubiquitin-activating enzyme (E1) and ubiquitin-conjugating enzymes (E2s) and in some cases also requires auxiliary substrate recognition proteins (E3s). Multiple E2s have been found, and these likely possess specificity for different classes of target proteins. Here we report the cloning and characterization of a gene (ubc-2) encoding a ubiquitin-conjugating enzyme which is involved in the selective degradation of abnormal and short-lived proteins in the nematode Caenorhabditis elegans. The nematode ubc-2 gene encodes a 16.7-kDa protein with striking amino acid sequence similarity to Saccharomyces cerevisiae UBC4 and UBC5 and Drosophila UbcD1. When driven by the UBC4 promoter, ubc-2 can functionally substitute for UBC4 in yeast cells; it rescues the slow-growth phenotype of ubc4 ubc5 mutants at normal temperature and restores their ability to grow at elevated temperatures. Western blots (immunoblots) of ubc4 ubc5 yeast cells transformed with ubc-2 reveal a protein of the expected size, which cross-reacts with anti-Drosophila UbcD1 antibody. C. elegans ubc-2 is constitutively expressed at all life cycle stages and, unlike yeast UBC4 and UBC5, is not induced by heat shock. Both trans and cis splicing are involved in the maturation of the ubc-2 transcript. These data suggest that yeast UBC4 and UBC5, Drosophila UbcD1, and C. elegans ubc-2 define a highly conserved gene family which plays fundamental roles in all eukaryotic cells.
Amino Acid Sequence↗