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1.
Int Nurs Rev ; 59(3): 394-401, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22897192

ABSTRACT

AIM: This study aimed to develop a ward-based writing coach programme to improve the quality of patient information in nursing documentation. BACKGROUND: Omissions in the patient information make nursing notes an unreliable source for care planning. Strategies to improve the quality of nursing documentation have been unsuccessful. An education programme, with one-to-one coaching in the clinical environment, was tested. METHOD: A concurrent mixed methods approach including a pre-post test intervention and control design for the quantitative component combined with a qualitative approach using a focus group (eight nurses) was used. Healthcare records for 87 patients (intervention) (46 pre and 41 post) and 88 patients (control) (51 pre and 37 post) were reviewed using the Nursing and Midwifery Content Audit Tool for quality nursing documentation. Sixteen nurses from two intervention wards participated in an introductory workshop with 2 weeks of coaching. No intervention was given to the control ward. RESULTS: No significant differences were found between the wards across the 14 criteria representing quality documentation; most criteria were present in 75% or more of the records. Improvements were demonstrated in both the intervention and comparison units. Themes identified from the focus groups included the impact these changes had on nurses and patients, perceived difficulties with nursing documentation, medicolegal aspects and the attributes of an effective writing coach. CONCLUSION: Writing coaching is a supportive approach to improving nursing documentation. Also, regular auditing prompts nurses to improve nursing documentation. Further research using larger sample sizes can further confirm or refute these findings.


Subject(s)
Inservice Training , Intensive Care Units , Nursing Records/standards , Humans
2.
Br J Dermatol ; 157(3): 580-2, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17573874

ABSTRACT

BACKGROUND: Isoeugenol is an important fragrance allergen. The cosmetic industry was recommended voluntarily to reduce concentrations of isoeugenol in finished cosmetic products from 0.2% to 0.02% in 1998. It was suspected that this would reduce the incidence of patch test positivity in individuals undergoing routine patch testing after approximately 2-3 years (the Dillarstone effect). OBJECTIVES: To review our patch test data since the change in practice by industry, to see if there has been an observable decrease in isoeugenol contact sensitivity. METHODS: We retrospectively analysed all subjects patch tested to isoeugenol 1% pet. in the St John's Department of Cutaneous Allergy over a period of 5 years, commencing 3 years after the changes. RESULTS: We identified 3636 subjects, 97 of whom were positive for isoeugenol. Year-on-year incidence shows an increasing trend, with an overall incidence of 2.67%. Using the exact Cochran-Armitage test, this ascending trend is statistically significant (P = 0.0182). Seventy-two of 97 isoeugenol-positive subjects were also positive to fragrance mix I. Other fragrances positive in these 97 patients included Myroxylon pereirae (30%), Evernia prunastri (22%) and eugenol (15%). CONCLUSIONS: We suspect that the increasing trend may be due to allergen substitution with compounds chemically related to isoeugenol, or which hydrolyse to isoeugenol itself.


Subject(s)
Allergens/adverse effects , Dermatitis, Allergic Contact/etiology , Eugenol/adverse effects , Perfume/adverse effects , Solvents/adverse effects , Adult , Female , Humans , Male , Middle Aged , Patch Tests , Perfume/chemistry
3.
Food Addit Contam ; 22(8): 716-25, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16147427

ABSTRACT

Bleaching earth (dried, powdered, bentonite-montmorillonite clay) is commonly used as a processing aid in edible oil refinement. Used bleaching earth may be incorporated into animal feed indirectly, for example because it is included into seed meal, or directly (e.g., as a binding agent). Control must be demonstrated to ensure that the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in feed ingredients do not infringe European Community regulations. The low legislative action level assigned is analytically challenging and may be at or below the limits of quantification achievable by many laboratories. A statistical comparison (following the IUPAC/ISO/AOAC protocol) was made of analyses of PCDDs and PCDFs in selected bleaching earth samples by laboratories from Europe and the USA to assess the comparability of data. Of 19 sets of results submitted by laboratories for replicate samples, 11 demonstrated acceptable agreement.


Subject(s)
Aluminum Silicates/chemistry , Animal Feed , Bentonite/chemistry , Benzofurans/analysis , Dietary Fats, Unsaturated , Polychlorinated Dibenzodioxins/analogs & derivatives , Animals , Clay , Europe , Polychlorinated Dibenzodioxins/analysis , Reproducibility of Results , Soil Pollutants/analysis , United States
4.
Br J Dermatol ; 153(2): 364-7, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16086750

ABSTRACT

BACKGROUND: Despite having a positive patch test reaction to para-phenylenediamine (PPD), some patients continue to dye their hair, while others are forced to give up or abandon this practice. This difference in patient behaviour could be due to the degree of sensitization. OBJECTIVES: To establish whether the ability to continue dyeing hair in PPD allergic patients is related to the strength of patch test reaction. To note differences in other clinical features in relation to the strength of patch test reaction. METHODS: We analysed retrospectively the patch test records of 400 sequential PPD-positive patients for the strength of patch test reaction (+, ++, +++) and different clinical features. Data were analysed using Cochran-Mantel-Haenszel chi2 tests. RESULTS: There was a strong linear relationship between the strength of patch test reaction and continuation with hair dyeing. Patients were more likely to report a history of hair dye reaction with increasing strength of patch test reaction. There was no difference in strength of patch test reaction in relation to age, site of rash, occupation (hairdressing) or history of atopic eczema. Overall concomitant reactivity with related aromatic amine allergens (benzocaine, N-isopropyl-N-phenyl-para-phenylenediamine, para-aminobenzoic acid) was infrequent. CONCLUSIONS: Patients with stronger patch test reactions (++, +++) are more likely to have a clear history of reacting to hair dye and are less likely to still be dyeing their hair.


Subject(s)
Drug Hypersensitivity/immunology , Hair Dyes/adverse effects , Phenylenediamines/immunology , Skin Tests , Adolescent , Adult , Aged , Aged, 80 and over , Allergens/immunology , Child , Cross Reactions , Dermatitis, Atopic/immunology , Female , Hair , Humans , Male , Middle Aged , Phenylenediamines/adverse effects , Retrospective Studies , Severity of Illness Index
5.
Avian Pathol ; 32(1): 69-80, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12745383

ABSTRACT

Tibial dyschondroplasia (TD) is a form of aberrant endochondral ossification in chickens, in that a plug of avascular cartilage (TD lesion) is formed within the growth plate. Histologically, the lesion is filled with apparently transitional chondrocytes that have been unable to differentiate to hypertrophic chondrocytes. We have examined the spatial expression of mRNAs for type X collagen, Indian hedgehog (Ihh) and Parathyroid Hormone-related protein (PTHrP) in the TD growth plate by in situ hybridization in order to ascertain at which stage chondrocyte differentiation is arrested in TD. In the normal growth plate, type X collagen mRNA was expressed by both prehypertrophic and hypertrophic chondrocytes. Indian Hedgehog mRNA was detected in a band of prehypertrophic chondrocytes and PTHrP expression was localized to a narrow band of prehypertrophic chondrocytes and in osteoblasts within the diaphysis. In TD sections, collagen X expression was seen within differentiating cells, within a small number of lesion cells, and within hypertrophic chondrocytes on the diaphyseal side of the lesion. Ihh expression was also seen within the differentiating cells and throughout the lesion. These data indicate that chondrocyte differentiation is arrested at the transitional stage just prior to hypertrophy. Contrary to the previously reported PTHrP expression patterns in TD chicks by immunohistochemistry, PTHrP mRNA was not detected in the TD lesion. This observation probably reflects the cessation of PTHrP gene expression by chondrocytes in the more severe TD lesions. The results from the present study also imply that the arrest of cell differentiation in TD is independent of PTHrP and that endochondral ossification in the post-hatch avian growth plate may involve additional regulatory pathways.


Subject(s)
Bone Diseases, Developmental/genetics , Bone Diseases, Developmental/veterinary , Collagen Type X/genetics , Growth Plate/metabolism , Peptide Hormones/genetics , Tibia/pathology , Trans-Activators/genetics , Animals , Chickens/genetics , Chickens/growth & development , Gene Expression Regulation, Developmental , Growth Plate/pathology , Hedgehog Proteins , In Situ Hybridization , Parathyroid Hormone-Related Protein , Poultry Diseases/genetics , Poultry Diseases/pathology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Tibia/metabolism
7.
Endocrinology ; 142(9): 4131-40, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11517192

ABSTRACT

Chondrocyte differentiation during embryonic bone growth is controlled by interactions between PTHrP and Indian hedgehog. We have now determined that the major components of this signaling pathway are present in the postembryonic growth plate. PTHrP was immunolocalized throughout the growth plate, and semiquantitative RT-PCR analysis of maturationally distinct chondrocyte fractions indicated that PTHrP, Indian hedgehog, and the PTH/PTHrP receptor were expressed at similar levels throughout the growth plate. However, patched, the hedgehog receptor, was more highly expressed in proliferating chondrocytes. Although all fractionated cells responded to PTHrP in culture by increasing thymidine incorporation and cAMP production and decreasing alkaline phosphatase activity, the magnitude of response was greatest in the proliferative chondrocytes. Bone morphogenetic proteins are considered likely intermediates in PTHrP signaling. Expression of bone morphogenetic protein-2 and 4--7 was detected within the growth plate, and PTHrP inhibited the expression of bone morphogenetic protein-4 and 6. Although organ culture studies indicated a possible paracrine role for epiphyseal chondrocyte-derived PTHrP in regulating growth plate chondrocyte differentiation, the presence within the postembryonic growth plate of functional components of the PTHrP-Indian hedgehog pathway suggests that local mechanisms intrinsic to the growth plate exist to control the rate of endochondral ossification.


Subject(s)
Animals, Newborn/physiology , Chondrocytes/cytology , Growth Plate/cytology , Proteins/physiology , Trans-Activators/physiology , Animals , Cell Differentiation/physiology , Chickens , Chondrocytes/drug effects , Culture Techniques , Gene Expression/drug effects , Gene Expression/physiology , Growth Plate/drug effects , Growth Plate/physiology , Hedgehog Proteins , Immunohistochemistry , Male , Parathyroid Hormone-Related Protein , Proteins/pharmacology
8.
Avian Pathol ; 30(4): 327-35, 2001 Aug.
Article in English | MEDLINE | ID: mdl-19184918

ABSTRACT

Parathyroid hormone-related peptide (PTHrP) has a key role in the growth of long bones, as it is a negative regulator of growth plate chondrocyte terminal differentiation. We have examined the distribution and gene expression levels of PTHrP in the growth plates of broiler chickens with tibial dyschondroplasia (TD) in order to determine whether increased expression of PTHrP is responsible for the delayed chondrocyte differentiation that is characteristic of this skeletal disorder. PTHrP protein distribution and gene expression levels were assessed by immunocytochemistry and reverse transcriptase-polymerase chain reaction, respectively. In growth plates of normal birds, PTHrP was found to be distributed throughout all maturational zones of the growth plate. In cartilage proximal to the TD lesion, PTHrP immunostaining and the level of PTHrP gene expression were similar to that observed in normal birds. In contrast, many chondrocytes within the centre of the TD lesion stained poorly for PTHrP and this was reflected in the lower levels of PTHrP mRNA detected in lesion cells. These results suggest that alterations in PTHrP distribution and gene expression are not primarily responsible for the delayed chondrocyte differentiation and hypertrophy noted in dyschondroplasia, but are a result of secondary changes due to the pathology of the condition.

9.
Poult Sci ; 79(7): 994-1004, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10901201

ABSTRACT

Growth plate cartilage is central to the process of bone elongation. Chondrocytes originating within the resting zone of the growth plate proceed through a series of intermediate phenotypes: proliferating, prehypertrophic and hypertrophic, before reaching a terminally differentiated state. Disruption of this chondrocyte maturational sequence causes many skeletal abnormalities in poultry such as tibial dyschondroplasia (TD), which is a common cause of deformity and lameness in the broiler chicken. Cell and matrix components of the growth plate have been studied in order to determine the cause(s) of the premature arrest of chondrocyte differentiation and retention of prehypertrophic chondrocytes observed in TD. Chondrocyte proliferation proceeds normally in TD, but markers of the differentiated phenotype, local growth factors, and the vitamin D receptor are abnormally expressed within the prehypertrophic chondrocytes above, and within, the lesion. Tibial dyschondroplasia is also associated with a reduced incidence of apoptosis, suggesting that the lesion contains an accumulation of immature cells that have outlived their normal life span. Immunolocalization studies of matrix components suggest an abnormal distribution within the TD growth plate that is consistent with a failure of the chondrocytes to fully hypertrophy. In addition, the collagen matrix of the TD lesion is highly crosslinked, which may make the formed lesion more impervious to vascular invasion and osteoclastic resorption. Recent studies have applied the techniques of differential display and semiquantitative reverse transcriptase-polymerase chain reaction to RNA obtained from discrete populations of growth plate chondrocytes of different maturational phenotypes. This strategy has allowed us to compare phenotypically identical cell fractions from normal and TD growth plates in an attempt to identify possible candidate genes for TD.


Subject(s)
Bone Development , Chondrocytes/physiology , Osteochondrodysplasias/veterinary , Poultry Diseases/physiopathology , Tibia , Animals , Apoptosis , Cell Differentiation , Collagen/chemistry , Collagen/physiology , Growth Plate/chemistry , Growth Plate/physiology , Osteochondrodysplasias/genetics , Osteochondrodysplasias/physiopathology
10.
Biochim Biophys Acta ; 1501(2-3): 180-8, 2000 Jun 15.
Article in English | MEDLINE | ID: mdl-10838191

ABSTRACT

Tibial dyschondroplasia (TD) appears to involve a failure of the growth plate chondrocytes within growing long bones to differentiate fully to the hypertrophic stage, resulting in a mass of prehypertrophic chondrocytes which form the avascular TD lesion. Many biochemical and molecular markers of chondrocyte hypertrophy are absent from the lesion, or show reduced expression, but the cause of the disorder remains to be identified. As differentiation to the hypertrophic state is impaired in TD, we hypothesised that chondrocyte genes that are differentially expressed in the growth plate should show altered expression in TD. Using differential display, four genes, B-cadherin, EF2, HT7 and Ex-FABP were cloned from chondrocytes stimulated to differentiate to the hypertrophic stage in vitro, and their differential expression confirmed in vivo. Using semi-quantitative RT-PCR, the expression patterns of these genes were compared in chondrocytes from normal and TD growth plates. Surprisingly, none of these genes showed the pattern of expression that might be expected in TD lesion chondrocytes, and two of them, B-cadherin and Ex-FABP, were upregulated in the lesion. This indicates that the TD phenotype does not merely reflect the absence of hypertrophic marker genes, but may be influenced by more complex developmental mechanisms/defects than previously thought.


Subject(s)
Antigens, CD , Antigens, Neoplasm , Antigens, Surface , Avian Proteins , Blood Proteins , Chondrocytes/metabolism , Gene Expression Regulation, Developmental/genetics , Osteochondrodysplasias/genetics , Tibia/metabolism , Animals , Basigin , Cadherins/genetics , Carrier Proteins/genetics , Cells, Cultured , Chickens , Cloning, Molecular , DNA-Binding Proteins/genetics , Fatty Acid-Binding Proteins , Growth Plate/growth & development , Growth Plate/metabolism , HMGB Proteins , Lipocalins , Membrane Glycoproteins/genetics , Nuclear Proteins/genetics , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , SOXB1 Transcription Factors , Tibia/growth & development , Transcription Factors
11.
Bone ; 25(4): 405-12, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10511106

ABSTRACT

Terminal differentiation of growth-plate chondrocytes is accompanied by the acquisition of a spherical morphology and a large increase in cell volume. These changes are likely to be associated with rearrangement of the cytoskeleton, but little information on this aspect of chondrocyte hypertrophy is available. We report a role for microtubules in the control of chondrocyte maturation and hypertrophy. Chick growth-plate chondrocytes were fractionated into five maturationally distinct populations by Percoll density gradient centrifugation, and agarose gel differential display analysis was performed. We identified a 1200 bp cDNA fragment derived from a transcript that was most highly expressed in the hypertrophic chondrocytes. After cloning and sequencing, FASTA and BLAST analysis revealed 100% identity to chick beta7-tubulin. Differential expression was confirmed in a reverse transcription-polymerase chain reaction (RT-PCR) assay using specific primers for a 343 bp fragment from the 3' untranslated region of beta7-tubulin. Beta7-tubulin was upregulated three-fold in fully hypertrophic chondrocytes compared with the other four fractions, which all had similar levels of expression. Immunocytochemical localization of beta-tubulin in chick growth-plate sections demonstrated little staining in the chondrocytes of the proliferating zone, but intense cytoplasmic staining was present in the large hypertrophic chondrocytes. In cell culture studies, the addition of colchicine (10(-6) mol/L) resulted in a higher rate of [3H]-thymidine uptake (36.0%; p < 0.001), but lower amounts of alkaline phosphatase activity (69.1%; p < 0.001), collagen (49.1%; p < 0.01), and glycosaminoglycan (43.3%; p < 0.01) accumulation within the cell-matrix layer. Further evidence for the involvement of microtubules in chondrocyte differentiation and hypertrophy was obtained by morphological assessment of colchicine-treated growth-plate explant cultures. A partial failure of chondrocyte hypertrophy was observed, although collagen type X immunoreactivity was noted within the interstitial matrix. Further studies are required to identify the exact role of microtubules in chondrocyte hypertrophy, but the results presented here suggest that upregulation of beta-tubulin may be required for increased microtubule synthesis during changes in cell size during the hypertrophic process. In addition, as cell-matrix interactions are required for chondrocyte maturation, microtubules may promote the differentiated phenotype as a result of their role in Golgi-mediated secretion of matrix proteins.


Subject(s)
Chondrocytes/cytology , Growth Plate/cytology , Microtubules/physiology , Tubulin/physiology , Animals , Cell Differentiation/physiology , Cell Size/physiology , Cells, Cultured , Chickens , Chondrocytes/physiology
12.
Anim Genet ; 30(4): 300-3, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10467705

ABSTRACT

The growth plate is a specialised region of cartilage located at the growing ends of long bones in higher vertebrates. It is responsible for longitudinal bone growth and is under the control of many local and systemic factors. The growth plate consists of an orderly arrangement of small proliferative and larger mature hypertrophic chondrocytes. This paper describes the isolation by differential display of a 988-bp cDNA fragment derived from a transcript that is more highly expressed in proliferating rather than hypertrophic chondrocytes of the chick growth plate. Using 3' RACE, a further 939 bp of cDNA sequence was obtained. The 1.9 kb sequence contains a 924-bp open reading frame encoding an unknown 308 amino acid protein. This protein has a putative transmembrane domain near its N-terminus and three dileucine motifs at its carboxy tail. This gene was expressed in all other tissues examined. A polymorphism was identified by SSCP analysis and the gene was mapped to the centromeric region of the short arm of chicken chromosome 1, close to the locus for autosomal dwarfism.


Subject(s)
Chickens/genetics , Growth Plate/metabolism , Membrane Proteins/genetics , 5' Untranslated Regions , Animals , Base Sequence , Bone Development/genetics , Chickens/metabolism , Chondrocytes/metabolism , Chromosome Mapping , DNA Primers/genetics , Female , Gene Expression , Growth Plate/cytology , Male , Membrane Proteins/metabolism , Pedigree , Polymorphism, Single-Stranded Conformational
13.
Biochim Biophys Acta ; 1448(3): 500-6, 1999 Jan 11.
Article in English | MEDLINE | ID: mdl-9990301

ABSTRACT

Growth plate chondrocytes progress through a proliferative phase before acquiring a terminally-differentiated phenotype. In this study we used Percoll density gradients to separate chick growth plate chondrocytes into populations of different maturational phenotype. By applying agarose gel differential display to these populations we cloned a cDNA encoding a novel 268 amino acid protein (3X11A). 3X11A contains two peptide motifs that are conserved in a recently identified superfamily of phosphotransferases. It is likely that 3X11A is a phosphatase, but its substrate specificity remains uncertain. 3X11A expression is upregulated 5-fold during chondrocyte terminal differentiation and its expression is approximately 100-fold higher in hypertrophic chondrocytes than in non-chondrogenic tissues. This suggests that 3X11A participates in a biochemical pathway that is particularly active in differentiating chondrocytes.


Subject(s)
Chondrocytes/enzymology , Phosphoric Monoester Hydrolases/genetics , Phosphoric Monoester Hydrolases/metabolism , Amino Acid Sequence , Animals , Base Sequence , Cell Differentiation , Chickens , Chondrocytes/cytology , Cloning, Molecular , Conserved Sequence , DNA Primers/genetics , DNA, Complementary/genetics , Gene Expression Regulation, Developmental , Gene Expression Regulation, Enzymologic , Growth Plate/cytology , Growth Plate/enzymology , Growth Plate/growth & development , Humans , Molecular Sequence Data , Phosphoric Monoester Hydrolases/chemistry , Sequence Homology, Amino Acid
15.
Biochim Biophys Acta ; 1396(3): 237-41, 1998 Mar 13.
Article in English | MEDLINE | ID: mdl-9545570

ABSTRACT

The technique of RNA differential display has been used extensively to clone differentially expressed genes from a wide variety of cells and tissues. Recently, a simplified method of cloning differential display products, separated on agarose gels, was described. Here we report an adaption of this method, using total RNA, to clone differentially expressed genes. The approach is simple and rapid, and requires only small quantities of total RNA. Utilising this approach, we have cloned three differentially regulated genes from chondrocytes stimulated to hypertrophy in vitro, and confirmed their pattern of expression by Northern blotting. These gene fragments were sequenced and found to correspond to known genes, although only one has previously been isolated from chondrocytes.


Subject(s)
Avian Proteins , Chondrocytes/chemistry , Chondrocytes/metabolism , Cloning, Molecular/methods , Electrophoresis, Agar Gel/methods , Gene Expression Regulation , Animals , Blotting, Northern , Carrier Proteins/genetics , Cells, Cultured , Chickens , DNA Primers , Fatty Acid-Binding Proteins , Keratins/genetics , Lipocalins , Peptide Elongation Factor 2 , Peptide Elongation Factors/genetics , Polymerase Chain Reaction/methods
17.
Parasitol Today ; 14(5): 202-6, 1998 May.
Article in English | MEDLINE | ID: mdl-17040752

ABSTRACT

Phage display involves the production and screening of large numbers of random peptide sequences of a specific length expressed on the surface of phage particles. This approach provides a powerful tool to probe the molecular basis of many biological processes, including host-parasite interactions. Phage display libraries have been used to study the binding specificity of numerous peptides and protein domains. Practical applications include the identification of peptide sequences that bind with high affinity to antibodies, enzymes or receptors, and that may serve as diagnostics and vaccine or drug candidates. Here, David Jefferies outlines the concept of phage display and summarizes recent developments in the field, with emphasis on those that may be of interest to parasitologists.

18.
Avian Pathol ; 26(1): 97-104, 1997.
Article in English | MEDLINE | ID: mdl-18483893

ABSTRACT

The efficacy of Lixiscope examination in detecting tibial dyschondroplasia (TD) is assessed utilising a thorough post-mortem examination with good histological backup. Forty-seven per cent more broilers had TD at post-mortem examination than when examined solely by Lixiscope. TD lesions detected by Lixiscope examination had a mean score greater than 3. The additional lesions detected at post-mortem examination usually had a score of 1. This indicates that the Lixiscope examination failed to detect small lesions. The prevalence of dyschondroplastic lesions in the proximal tarsometatarsi indicates that this site may be of value to score in addition to the proximal tibiotarsus and use in selection. Disruption of the proliferative zone within some dyschondroplastic growth plates indicated that in a proportion of broilers there is a link between TD and rickets. The Lixiscope is an effective tool for detecting large TD lesions, but fails to detect smaller lesions. To minimize the susceptibility of genetic lines of broilers to TD it may be necessary to use progeny testing.

19.
Nucleic Acids Res ; 24(2): 272-81, 1996 Jan 15.
Article in English | MEDLINE | ID: mdl-8628650

ABSTRACT

The major surface antigen of procyclic and epimastigote forms of Trypanosoma congolense in the tsetse fly is GARP (glutamic acid/alanine-rich protein), which is thought to be the analogue of procyclin/PARP in Trypanosoma brucei. We have studied two T.congolense GARP loci (the 4.3 and 4.4 loci) whose transcription is alpha-amanitin sensitive. Whilst a transcriptional gap 5' of the first GARP gene in the cloned region of the 4.4 locus could not be detected, such a gap was present in the 5' flank of the first GARP gene in the 4.3 locus. We have located a GARP transcription start site and, using reporter gene constructs containing a putative GARP promoter region in transient transfection studies, we have demonstrated promoter activity for the test region in T.congolense. There are species-specific differences in sequences regulating expression of the two major surface antigens, GARP and procyclin/PARP: the GARP promoter is inactive in T.brucei while the procyclin/PARP promoter is inactive in T.congolense. We have defined the splice acceptor site for the 4.3 GARP gene by sequencing and by 5' RT-PCR and demonstrated microheterogeneity in GARP polyadenylation by 3' RT-PCR. It appears that some GARP and procyclin/PARP RNA processing signals, although similar, are also species-specific.


Subject(s)
Amanitins/pharmacology , Membrane Glycoproteins/genetics , Promoter Regions, Genetic/genetics , Protozoan Proteins/genetics , Transcription, Genetic/drug effects , Trypanosoma congolense/genetics , Animals , Antigens, Protozoan/genetics , Base Sequence , Gene Expression Regulation , Genes, Protozoan/genetics , Molecular Sequence Data , RNA Processing, Post-Transcriptional/genetics , RNA Splicing/genetics , RNA, Messenger/analysis , RNA, Messenger/metabolism , RNA, Protozoan/analysis , RNA, Protozoan/metabolism , Species Specificity , Trypanosoma brucei brucei/genetics , Trypanosoma congolense/immunology
20.
EMBO J ; 14(12): 2925-34, 1995 Jun 15.
Article in English | MEDLINE | ID: mdl-7796818

ABSTRACT

The variant surface glycoprotein (VSG) and procyclin are the respective major surface antigens of the bloodstream and the procyclic forms of Trypanosoma brucei. These proteins and their mRNAs are both the most abundant and absolutely characteristic of their respective life cycle stages. We show that the 3'-terminal region of these mRNAs regulates expression of a reporter gene in an inverse manner, depending on the developmental form of the parasite. In the case of VSG mRNA, the 97 nt sequence upstream from the polyadenylation site is responsible for these effects. The regulation occurs through a variation of mRNA abundance which is not due to a change in primary transcription. In the bloodstream form this effect is manifested by an increase in RNA stability, whereas in the procyclic form it seems to be related to a reduction in the efficiency of mRNA maturation. The 3'-end of VSG mRNA can obviate the 5- to 10-fold stimulation of transcription driven by the procyclin promoter during differentiation from the bloodstream to the procyclic form. The predominance of posttranscriptional over transcriptional controls is probably linked to the organization of the trypanosome genome in polycistronic transcription units.


Subject(s)
Gene Expression Regulation, Developmental/genetics , Membrane Glycoproteins/genetics , Protozoan Proteins , RNA, Messenger/genetics , Trypanosoma brucei brucei/genetics , Variant Surface Glycoproteins, Trypanosoma/genetics , Animals , Base Sequence , Genes, Reporter/genetics , Molecular Sequence Data , Promoter Regions, Genetic/genetics , RNA, Messenger/metabolism , RNA, Protozoan/genetics , RNA, Protozoan/metabolism , Regulatory Sequences, Nucleic Acid/genetics , Transcription, Genetic , Trypanosoma brucei brucei/growth & development
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