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PubMed1996

Identification of an essential core element and stimulatory sequences in a Kluyveromyces lactis ARS element, KARS101.

A Kluyveromyces lactis chromosomal sequence of 913 bp is sufficient for replication in Saccharomyces cerevisiae and K. lactis. This fragment contains a 12 bp sequence 5'-ATTTATTGTTTT-3' that is related to the S. cerevisiae ACS (ARS consensus sequence). This dodecamer was removed by site-directed mutagenesis and the effect on K. lactis and S. cerevisiae ARS (autonomous replicating sequence) activity was determined. The dodecamer is essential for S. cerevisiae ARS function but only contributes to K. lactis ARS activity; therefore, its role in K. lactis is unlikely to be the same as that of the essential S. cerevisiae ACS. A 103 bp subclone was found to retain ARS activity in both yeasts, but the plasmid was very unstable in S. cerevisiae. Deletion and linker substitution mutagenesis of this fragment was undertaken to define the DNA sequence required for K. lactis ARS function and to test whether the sequence required for ARS activity in K. lactis and S. cerevisiae coincide. We found a 39 bp core region essential for K. lactis ARS function flanked by sequences that contribute to ARS efficiency. The instability of the plasmid in S. cerevisiae made a fine-structure analysis of the S. cerevisiae ARS element impossible. However, the sequences that promote high-frequency transformation in S. cerevisiae overlap the essential core of the K. lactis ARS element but have different end-points.

Base Sequence↗

PubMed1999

A novel 14-base-pair regulatory element is essential for in vivo expression of murine beta4-galactosyltransferase-I in late pachytene spermatocytes and round spermatids.

During murine spermatogenesis, beginning in late pachytene spermatocytes, the beta4-galactosyltransferase-I (beta4GalT-I) gene is transcribed from a male germ cell-specific start site. We had shown previously that a 796-bp genomic fragment that flanks the germ cell start site and contains two putative CRE (cyclic AMP-responsive element)-like motifs directs correct male germ cell expression of the beta-galactosidase reporter gene in late pachytene spermatocytes and round spermatids of transgenic mice (N. L. Shaper, A. Harduin-Lepers, and J. H. Shaper, J. Biol. Chem. 269:25165-25171, 1994). We now report that in vivo expression of beta4GalT-I in developing male germ cells requires an essential and previously undescribed 14-bp regulatory element (5'-GCCGGTTTCCTAGA-3') that is distinct from the two CRE-like sequences. This cis element is located 16 bp upstream of the germ cell-specific start site and binds a male germ cell protein that we have termed TASS-1 (transcriptional activator in late pachytene spermatocytes and round spermatids 1). The presence of the Ets signature binding motif 5'-GGAA-3' on the bottom strand of the TASS-1 sequence (underlined sequence) suggests that TASS-1 is a novel member of the Ets family of transcription factors. Additional transgenic analyses established that an 87-bp genomic fragment containing the TASS-1 regulatory element was sufficient for correct germ cell-specific expression of the beta-galactosidase reporter gene. Furthermore, when the TASS-1 motif was mutated by transversion, within the context of the original 796-bp fragment, transgene expression was reduced 12- to 35-fold in vivo.

Animals↗

PubMed2001

Transcription of the Schizosaccharomyces pombe U2 gene in vivo and in vitro is directed by two essential promoter elements.

As compared to the metazoan small nuclear RNAs (snRNAs), relatively little is known about snRNA synthesis in unicellular organisms. We have analyzed the transcription of the Schizosaccharomyces pombe U2 snRNA gene in vivo and in the homologous in vitro system. Deletion and linker-scanning analyses show that the S.pombe U2 promoter contains at least two elements: the spUSE centered at -55, which functions as an activator, and a TATA box at -26, which is essential for basal transcription. These data point to a similar architecture among S.pombe, plant and invertebrate snRNA promoters. Factors recognizing the spUSE can be detected in whole cell extracts by DNase I footprinting and competition studies show that the binding of these factors correlates with transcriptional activity. Electrophoretic mobility shift assays and gel-filtration chromatography revealed a native molecular mass of approximately 200 kDa for the spUSE binding activity. Two polypeptides of molecular masses 25 and 65 kDa were purified by virtue of their ability to specifically bind the spUSE.

Binding, Competitive↗

PubMed1984

Brain trace element concentrations in aging.

Trace element concentrations were determined in various human brain regions over the complete life span using instrumental neutron activation analysis. Several different patterns of trace element alteration were observed with age. Brain Al, Cl and Na concentrations increase with advancing age, while K, P and Rb decline. Ag, Co, Fe, Sb and Sc concentrations increase up to the 40 to 79 age range then decline. Br, Se and Zn remain relatively constant throughout adult life. Hg, Mn and Cs show no consistent trend with age. In infant brains Br and Cl increase and Al, Cr, Cs, Fe, Mn, P, Rb, Sc, Se and Zn decrease compared to adults. The essential elements that remain within narrow concentration limits throughout adult life suggest the presence of an efficient homeostatic mechanism for their regulation in the brain, while those that are altered with age suggest modifications in control mechanisms or altered relationships with other elements. Increased concentrations of non-essential elements may reflect accumulation from our environment, impaired removal or altered balance with other elements.

Adult↗

PubMed1999

Effects of weight loss and exercise on the distribution of lead and essential trace elements in rats with prior lead exposure.

We studied the effects of weight loss and non-weight-bearing exercise (swimming) on blood and organ lead and essential metal concentrations in rats with prior lead exposure. Nine-week-old female Sprague-Dawley rats (n = 37) received lead acetate in their drinking water for 2 weeks, followed by a 4-day latency period without lead exposure. Rats were then randomly assigned to one of six treatment groups: weight maintenance with ad libitum feeding, moderate weight loss with 20% food restriction, and substantial weight loss with 40% food restriction, either with or without swimming. Blood lead concentrations were measured weekly. The rats were euthanized after a 4-week period of food restriction, and the brain, liver, kidneys, quadriceps muscle, lumbar spinal column bones, and femur were harvested for analysis for lead, calcium, copper, iron, magnesium, and zinc using atomic absorption spectrophotometry. Both swimming and nonswimming rats fed restricted diets had consistently higher blood lead concentrations than the ad libitum controls. Rats in the substantial weight loss group had higher organ lead concentrations than rats in the weight maintenance group. Rats in the moderate weight loss group had intermediate values. There were no significant differences in blood and organ lead concentrations between the swimming and nonswimming groups. Organ iron concentrations increased with weight loss, but those of the other metals studied did not. Weight loss also increased hematocrits and decreased bone density of the nonswimming rats. The response of lead stores to weight loss was similar to that of iron stores because both were conserved during food restriction in contrast to decreased stores of the other metals studied. It is possible that weight loss, especially rapid weight loss, could result in lead toxicity in people with a history of prior excessive lead exposure.

Animals↗

PubMedDate not supplied

Importance of international cooperation in food safety.

All countries need to ensure that national food supplies are safe, of good quality and available in adequate amounts at affordable prices to ensure good nutrition and health for all population groups. The enforcement of food standards by efficient national food control authorities in domestic markets and at the points of import and export has been increasingly recognized as a means of raising the value of exported goods by reducing the number of rejected or reconditioned consignments, and of ensuring the safety of the food and its acceptability by the final consumer. However, those national efforts have sometimes induced some non-tariff barriers to food trade and distribution. In addition, new developments in the technologies of food production, processing and marketing pose a new challenge to ensure safety of food. The strengthening of national food control infrastructures in particular in developing countries including the strengthening of staff capabilities, the need for harmonization of food at international levels, the need for collection and exchange of data on food control and food contamination issues are essential elements to ensure food safety in the world. International cooperation has an important role to play in achieving these essential elements.

Food Additives↗

PubMed1996

Developmental patterns of aluminum and five essential mineral elements in the central nervous system of the fetal and infant guinea pig.

Al is found in the developing conceptus, but little information is available concerning its tissue distribution and its changes in concentration with age. Because Al has affinity for many of the same biological ligands as the essential mineral cations Ca, Mg, Zn, Fe, and Mn, we hypothesized that Al might show a pattern of developmental concentrations that was similar to one or more of these elements in the brain, a major target of Al toxicity. Concentrations of Al, Ca, Mg, Zn, Fe, and Mn were measured in spinal cord, brainstem, cerebellum, and forebrain of guinea pig fetuses on gestation day (GD) 30 and 45, at birth, and on postnatal day (PND) 3, 6, and 12. Dams were fed commercial guinea pig chow, which contained 47 micrograms Al/g. Tissue Al and Mn were measured with electrothermal atomic absorption spectrophotometry (ETAAS), and the other elements with inductively coupled axial plasma spectroscopy (ICAP-AES). Al concentrations in the brain regions were highest in spinal cord, brainstem, and cerebellum, and decreased during late gestation and lactation. Al did not show marked increases in regional brain concentrations during the final third of gestation as did Fe, Mg, and Zn. In contrast to Fe and Ca, Al did not accumulate in placenta. Al was the only element to show higher concentrations in spinal cord than in any other tissue at birth. In summary, the tissue distribution of Al did not follow that of essential cations as examined in this study.

Aluminum↗

PubMed2001

The hairpin loop but not the bulged C of the iron responsive element is essential for high affinity binding to iron regulatory protein-1.

Vertebrates control intracellular iron concentration principally through the interaction of iron regulatory proteins with mRNAs that contain an iron responsive element, a small hairpin with a bulged C. The hairpin loop and bulged C have previously been assumed to be critical for binding and have been proposed to make direct contact with the iron regulatory proteins. However, we show here that a U or G can be substituted for the bulged C provided that specific nucleotides are also present within internal loops. The K(d), IC(50) and chemical modifications of the iron responsive element variants are similar to the wild-type. Results are more consistent with a role in which the C-bulge functions to orient the hairpin for optimal protein binding rather than to directly contact the protein. Characterization of these novel iron responsive element variants may facilitate the identification of additional mRNAs whose expression is controlled by iron regulatory proteins, as well as provide insight into the nature of a critical RNA-protein interaction.

Base Sequence↗

PubMed1997

Trace elements in pleural effusions.

When the secretion of pleural fluids exceeds their resorption, liquid (pleural effusion ) will accumulate between the visceral and parietal pleura. Pleural effusions derived from the liquid components of blood are expected to contain trace elements and may, as a sink for trace elements, deprive the body of needed essential elements upon their removal by medical intervention. Consequently, patients may be at risk of drifting into trace-element deficiencies. Because the literature is almost devoid of data about trace elements in effusions, the concentrations of 14 trace elements (Ba, Ca, Cd, Co, Cs, Cu, Mg, Mn, Mo, Pb, Rb, Sn, Sr, Zn) were determined simultaneously by inductively-coupled argon-plasma mass spectrometry (ICP-MS) in effusions from 17 patients. The median values for the concentrations of Rb (209 microgram/kg, range 104-334 microgram/kg) and Cs (1.5 micrograms/kg, range 0.8-2.4 microgram/kg) in the effusions were almost the same as in the sera. The concentrations of Mg (range 15-22 mg/kg), Ca range 52-91 mg/kg), Sr (range 12-37 micrograms/kg), and Ba (range 1.4-18.2 micrograms/kg) were consistently lower in the effusions than in the sera by 18% for Mg, 26% Ca 14% for Sr, and 88% for Ba (percentages based on median in serum as 100%). The concentrations of the essential trace elements Co (range 0.16-0.5 microgram/kg), Cu (130-902 micrograms/kg), Mn (0.2-2.2 micrograms/kg), Mo (0.4-1.5 micrograms/kg), Sn (0.4-1.2 micrograms/kg), and Zn (27-1931 micrograms/kg) in the effusions are generally lower (25-55% based on median) than in the corresponding sera, although a few effusions have higher concentrations of Co, Mn Mo, or Zn than in the sera. The concentrations of Cd (range 0.2-0.5 microgram/kg) in the effusions were approximately the same as in the sera for three patients, considerably lower than in the sera for four patients, and considerably higher for three patients. The concentrations for lead (range 0.6-45 micrograms/kg) in the effusions were generally much higher than in the sera. The effusions were not significantly contaminated with lead-rich erythrocytes. The concentrations of Ca, Cu, and Zn in the effusions correlated positively with the protein concentrations in the effusions. One kilogram of the effusions contain from 10-30% of the trace elements present in the entire volume of serum in circulation.

Adult↗

PubMed1992

Three essential promoter elements mediate tumour necrosis factor and interleukin-1 activation of the granulocyte-colony stimulating factor gene.

Granulocyte-colony stimulating factor (G-CSF) is a haemopoietic growth factor produced by mesenchymal cells but not T lymphocytes after stimulation with specific cytokines or mitogens. A 330 bp promoter fragment of the human G-CSF gene induced reporter gene expression in human embryonic lung fibroblasts in response to tumor necrosis factor-alpha (TNF-alpha) or interleukin-1 beta (IL-1 beta). The same promoter fragment was not active in Jurkat T cells nor did it respond to phorbol ester in either cell type. At least three distinct elements, the CK-1 sequence, a decanucleotide present in haemopoietic growth factor genes, an NF-IL-6 consensus sequence and a consensus octamer sequence, were essential in the G-CSF promoter for TNF-alpha and IL-1 beta response. Mutation of any of these sequences abolished promoter function. In contrast, mutation of two other consensus protein binding sequences, i.e. a Pu-1 site and a CK-2-like sequence, did not eliminate promoter function. Both the CK-1 and octamer sequences acted independently as TNF-alpha and IL-1 beta responsive elements upstream of a heterologous promoter. The response of the octamer sequence and the 330 bp promoter but not the CK-1 sequence was greater with IL-1 beta than TNF-alpha reflecting a similar response of the endogenous gene.

Base Sequence↗

PubMed2002

Analysis of sequence upstream of the endogenous H19 gene reveals elements both essential and dispensable for imprinting.

Imprinting of the linked and oppositely expressed mouse H19 and Igf2 genes requires a 2-kb differentially methylated domain (DMD) that is located 2 kb upstream of H19. This element is postulated to function as a methylation-sensitive insulator. Here we test whether an additional sequence 5' of H19 is required for H19 and Igf2 imprinting. Because repetitive elements have been suggested to be important for genomic imprinting, the requirement of a G-rich repetitive element that is located immediately 3' to the DMD was first tested in two targeted deletions: a 2.9-kb deletion (Delta D MD Delta G) that removes the DMD and G-rich repeat and a 1.3-kb deletion (Delta G) removing only the latter. There are also four 21-bp GC-rich repetitive elements within the DMD that bind the insulator-associated CTCF (CCCTC-binding factor) protein and are implicated in mediating methylation-sensitive insulator activity. As three of the four repeats of the 2-kb DMD were deleted in the initial 1.6-kb Delta DMD allele, we analyzed a 3.8-kb targeted allele (Delta 3.8kb-5'H19), which deletes the entire DMD, to test the function of the fourth repeat. Comparative analysis of the 5' deletion alleles reveals that (i) the G-rich repeat element is dispensable for imprinting, (ii) the Delta DMD and Delta DMD Delta G alleles exhibit slightly more methylation upon paternal transmission, (iii) removal of the 5' CTCF site does not further perturb H19 and Igf2 imprinting, suggesting that one CTCF-binding site is insufficient to generate insulator activity in vivo, (iv) the DMD sequence is required for full activation of H19 and Igf2, and (v) deletion of the DMD disrupts H19 and Igf2 expression in a tissue-specific manner.

Alleles↗

PubMed1989

[Changes in trace-element concentrations after intravenous injection of an essential trace-element preparation for parenteral use in rats].

This experiment was carried out to investigate the effects of intravenous injection of an essential trace-element preparation (TE-5) on iron, zinc, copper and manganese concentrations, and blood biochemical and hematological parameters in rats. The rats were treated by intravenous injection of TE-5 for 7 days and the following results were obtained: 1) Neither a 0.04 nor a 0.4 ml/kg/day injection of TE-5 affected the iron, zinc, copper and manganese concentrations in tissues. 2) At a higher dose (1.2 ml/kg/day), iron concentrations in liver and spleen, zinc concentrations in liver, kidney, tibia and plasma, copper concentrations in heart, kidney and whole blood, and manganese concentrations in brain, heart, spleen, kidney, femoral muscle, tibia and whole blood increased. 3) At the highest does (4 ml/kg/day), all rats died and iron, zinc, copper and manganese concentrations in tissues increased remarkably. 4) With injections of TE-5 (0.04-1.2 ml/kg/day), hemoglobin, hematocrit, alkaline phosphatase activity and blood urea nitrogen decreased slightly. These results suggest that iron, zinc, copper and manganese concentrations, and blood biochemical and hematological parameters are maintained at doses up to 0.4 ml/kg/day of TE-5, but that doses higher than that destroy homeostasis.

Animals↗

PubMed1998

Aspects of the bioinorganic chemistry of silicon in conjunction with the biometals calcium, iron and aluminium.

Silicon, in its various forms (silicic acid (Si(OH)4) through to hydrated amorphous silica (SiOn(OH)4-2n, n = 2-4) is important in geological and biological processes. Silicon is considered to be an 'essential' element for some plants and higher animals and when present as silica imparts structural, defensive and photosynthetic advantages to many plants. For the majority of essential elements specific molecular binding sites have been identified, but this is not the case for silicon. This has lead to the proposal that silicon may not act directly on biological systems but may exert its influence via interactions with biometals. Metals for which this may be a viable option include aluminium, iron and calcium, all of which can be found co-located with silicon in both minerals and living organisms. This article briefly reviews the pertinent solution and solid state chemistry of silicon in relation to aluminium, iron and calcium. Examples where silicon and an additional metal are found in solid state phases are described. The biological systems where these deposits are found are extremely complex and preliminary results from a model system designed to study silicon-biometal interactions are described.

Aluminum↗

PubMed2002

Amelioration of mercurial toxicity by manganese. I. A case study in mung bean seedling.

Mercury, a non essential element renders inhibitory effect on many physiological activities of plants even at a low concentration. Plants absorb "Hg" from soil through root system. Manganese, an essential element has been found to counter the inhibitory effect of mercury mostly by preventing it's uptake from soil. Mung bean (Vigna radiata L. Wilczek) cv. Pusa Baisakhi grown in individual (1, 10, 100 and 1000 ppm) solution of Hg and Mn showed varied uptake of these heavy metals. However, in combined solutions (1 : 1, 10 : 1 and 1 : 10 ppm Hg : Mn), mercury uptake was mostly prevented in presence of 10 ppm Mn, indicating it's ameliorating effect.

Drug Interactions↗

PubMed1992

A conserved 11 nucleotide sequence contains an essential promoter element of the maize mitochondrial atp1 gene.

To determine the structure of a functional plant mitochondrial promoter, we have partially purified an RNA polymerase activity that correctly initiates transcription at the maize mitochondrial atp1 promoter in vitro. Using a series of 5' deletion constructs, we found that essential sequences are located within--19 nucleotides (nt) of the transcription initiation site. The region surrounding the initiation site includes conserved sequence motifs previously proposed to be maize mitochondrial promoter elements. Deletion of a conserved 11 nt sequence showed that it is critical for promoter function, but deletion or alteration of conserved upstream G(A/T)3-4 repeats had no effect. When the atp1 11 nt sequence was inserted into different plasmids lacking mitochondrial promoter activity, transcription was only observed for one of these constructs. We infer from these data that the functional promoter extends beyond this motif, most likely in the 5' direction. The maize mitochondrial cox3 and atp6 promoters also direct transcription initiation in this in vitro system, suggesting that it may be widely applicable for studies of mitochondrial transcription in this species.

Base Sequence↗

PubMed1993

Computerized management of respiratory care.

Respiratory care as an organized discipline is only about 45 years old, and the management of this dynamic allied health profession has usually been characterized by a demand-for-service mentality. As pressure continues to control costs, those departments that maximize quality patient care cost-effectively with thoroughly documented outcomes are in a better position to compete for future resources. The practice of respiratory care is changing as is the practice of medical care in general. Accountability for resource consumption and the quality of the product delivered are essential elements in the delivery of respiratory modalities. We have developed and implemented a comprehensive patient-data-based approach to the management of respiratory care. The essential elements of this approach are (1) relative-value-unit procedure base; (2) individual, shift, and department productivity that is attached to the annual performance review process; (3) management reporting on a 24-hour basis, with biweekly review at the management level; (4) development and implementation of a comprehensive patient-data-documentation system that permits automatic patient billing and 100% data review for quality-assurance documentation; (5) the development of a medical alerting system that alerts the Medical Director and Respiratory Care staff to potentially harmful events that, if untreated, may result in increased morbidity or mortality; and (6) the development of concurrent and retrospective tools for patient-outcomes research. These functions are supported by an active Medical Informatics Department that is nationally recognized in medical computing and logic application.

Cost-Benefit Analysis↗

PubMed1998

Influencing physicians: the three critical elements of a successful strategy.

UNLABELLED: This activity is designed for leaders and managers of healthcare organizations, particularly those involved in the development of physician incentive and physician management programs. GOAL: To describe the challenges inherent in influencing physicians and review the essential elements of any successful strategy for achieving physician support and participation. OBJECTIVES: 1. Describe the reasons why healthcare organizations and medical groups need to influence physicians to be successful. 2. Cite the reasons why it is difficult to influence physicians. 3. Review the current strategies healthcare organizations and medical groups use to influence physicians. 4. Outline the three essential elements of any program designed to influence physicians.

Behavior↗

PubMed1999

Molecular interactions between single-stranded DNA-binding proteins associated with an essential MCAT element in the mouse smooth muscle alpha-actin promoter.

Transcriptional activity of the mouse vascular smooth muscle alpha-actin gene in fibroblasts is regulated, in part, by a 30-base pair asymmetric polypurine-polypyrimidine tract containing an essential MCAT enhancer motif. The double-stranded form of this sequence serves as a binding site for a transcription enhancer factor 1-related protein while the separated single strands interact with two distinct DNA binding activities termed VACssBF1 and 2 (Cogan, J. G., Sun, S., Stoflet, E. S., Schmidt, L. J., Getz, M. J., and Strauch, A. R. (1995) J. Biol. Chem. 270, 11310-11321; Sun, S., Stoflet, E. S., Cogan, J. G., Strauch, A. R., and Getz, M. J. (1995) Mol. Cell. Biol. 15, 2429-2936). VACssBF2 has been recently cloned and shown to consist of two closely related proteins, Puralpha and Purbeta (Kelm, R. J., Elder, P. K., Strauch, A. R., and Getz, M. J. (1997) J. Biol. Chem. 272, 26727-26733). In this study, we demonstrate that Puralpha and Purbeta interact with each other via highly specific protein-protein interactions and bind to the purine-rich strand of the MCAT enhancer in the form of both homo- and heteromeric complexes. Moreover, both Pur proteins interact with MSY1, a VACssBF1-like protein cloned by virtue of its affinity for the pyrimidine-rich strand of the enhancer. Interactions between Puralpha, Purbeta, and MSY1 do not require the participation of DNA. Combinatorial interactions between these three single-stranded DNA-binding proteins may be important in regulating activity of the smooth muscle alpha-actin MCAT enhancer in fibroblasts.

Actins↗