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R Wall

Publications and source records attributed to R Wall.

At least 109 records · Page 6Linked to original sources
PubMed1994

Lamb tail docking: a controlled field study of the effects of tail amputation on health and productivity.

A detailed study of the effects of tail docking on lamb health and productivity was prompted by current concern about the welfare aspects of lamb tail amputation. Using a controlled field trial, comparing over 3000 docked and undocked lambs on seven farms, the effects of tail docking on mortality, blowfly strike and production variables were examined. The incidence of blowfly strike was strongly and consistently higher in undocked than docked lambs (rate ratio 6.03, 95 per cent confidence interval (CI) 2.99 to 12.19 for male lambs and 4.25, 95 per cent CI 2.25 to 8.01 for female lambs). The incidence of faecal soiling of the breech was slightly higher in undocked lambs and was identified as an important independent risk factor for blowfly strike. Both the mortality and production parameters were similar for docked and undocked lambs. It was concluded that tail docking protected against blowfly strike, with little evidence of any detrimental effect on lamb mortality and production.

Amputation, Surgical↗
PubMed1994

Responses of the sheep blowflies Lucilia sericata and L. cuprina to odour and the development of semiochemical baits.

The literature relating to the attraction of the sheep blowflies Lucilia sericata and Lucilia cuprina to their ovine hosts is reviewed. The responses of the two species are similar and different components of the behaviour leading to host location and oviposition appear to involve at least two distinct sets of semiochemical cues. Activation, upwind orientation and landing appear to occur in response to putrefactive sulphur-rich volatiles, originating from bacterial decomposition products. Oviposition is elicited primarily by the presence of decomposition products. Oviposition is elicited primarily by the presence of ammonia-rich compounds; moisture, pheromones and tactile stimuli may also act as oviposition stimuli. There is a pronounced sex difference in the response of Lucilia to semiochemicals with a higher proportion of females attracted than males and a higher proportion of gravid than non-gravid females. While the mechanisms of host location by Lucilia are of intrinsic interest, understanding the responses to semiochemicals is important in the attempt to develop powerful synthetic baits for deployment with the traps or targets used for population sampling or suppression. The literature is discussed with respect to the development of synthetic semiochemical baits.

Animals↗
PubMed1994

Blowfly strike in England and Wales: the relationship between prevalence and farm and management factors.

In order to develop and evaluate control strategies for blowfly strike, a greater understanding of the epidemiology is essential. A postal survey of sheep farmers yielded information about ten farm and management factors and their relationship to blowfly strike prevalence. The risk of a farm reporting at least one case of blowfly strike increased as flock size and stocking density increased (adjusted odds ratio of 1.13 for an increase in flock size of 100 sheep and 1.38 for an increase in stocking density of ten sheep per hectare). As farm altitude increased, the risk of blowfly strike decreased (adjusted odds ratio 0.67 for an increase in farm altitude of 100 m). The risk of high strike prevalence (more than 2% of sheep struck) decreased as both farm altitude and flock size increased. High strike prevalence was also associated with on-farm sheep carcase disposal (odds ratio 1.35). Farmers in the south-west of England were more likely to report at least one case of blowfly strike and high strike prevalence compared to all other regions.

Agriculture↗
PubMed1993

Multiple motifs regulate the B-cell-specific promoter of the B29 gene.

The B-cell-specific B29 and mb1 genes code for covalently linked proteins (B29 or Ig beta and mb1 or Ig alpha, respectively) associated with membrane immunoglobulins in the antigen receptor complex on B cells. We have functionally analyzed the upstream region of the B29 gene and have identified a 164-bp region which comprises the minimal promoter responsible for B-cell-specific transcription. Linker scanning mutagenesis of this minimal promoter has established that both the previously identified octamer motif and a DNA motif that binds an unknown protein factor are critical for B29 gene expression in a pre-B-cell and B-cell line. Further mutations showed that binding motifs for Ets, microB/LyF1, and Sp1 also significantly contributed to the overall activity of the minimal B29 promoter. However, the relative contribution of certain motifs to promoter activity was different in a pre-B versus a B-cell line. The microB/LyF1 motif was necessary for full promoter activity in the pre-B cells but was not required in the B cells.

Animals↗
PubMed1993

Multiple B29 containing complexes on murine B lymphocytes. Common and stage-restricted Ig-associated polypeptide chains.

The B29 gene is specifically expressed in all cells of the B lymphocyte lineage, and the B29 protein is disulfide-linked to the protein product of at least one other gene, known as mb-1. The noncovalent association of these heterodimers with Ig H chains is thought to be required for surface expression and signal transmission by B cell Ag receptors. We now demonstrate by two-color immunofluorescence a direct correlation between B29 density and surface Ig expression on normal spleen and bone marrow cells. The proportion of B29 in Ag receptor complexes appears to be relatively constant across major B lymphocyte subpopulations. Multiple B29-containing heterodimers were resolved on normal spleen cells by surface labeling, immunoprecipitation, two-dimensional gel analysis, and immunoblotting. As with lymphoma cells in our earlier study, the conditions of detergent extraction were critical to detection of certain species. Many laboratories have observed a family of 69- to 85-kDa heterodimers that are extracted with digitonin. These species are clearly Ig-associated, and are coprecipitated with anti-Ig antibodies. We found that extraction with Triton X-100 revealed an additional pair of 52- to 58-kDa heterodimers, where B29 was disulfide-bonded to a protein of approximately 23 kDa. The latter was detectable by immunoblotting with antibodies to extracellular, but not cytoplasmic, portions of mb-1. We found that, with mature cells, both conventional and low molecular mass heterodimers were solubilized with digitonin, but only detectable if Triton was present during immunoprecipitation. Thus, a protein having partial serologic identity with mb-1 forms heterodimers that are cryptic on splenic B cells, and possibly not directly associated with surface Ig molecules. In contrast, both types of heterodimers were readily detectable on late stage pre-B cells, regardless of detergent used for extraction or antibody used for immunoprecipitation. In that situation, both low- and high molecular mass heterodimers were associated with surface Ig. These findings increase our understanding of the B lymphocyte Ag receptor complex and indicate that its components may change as a function of differentiation.

Animals↗
PubMed1993

Alternatively spliced pp52 mRNA in nonlymphoid stromal cells.

The 52-kDa phosphoprotein, also reported as lymphocyte-specific gene 1 and WP34, is transcribed as a 1.6-kb mRNA in B lymphocytes, B cell lines, and untransformed T cells. This gene encodes a cytoplasmic and plasma membrane-associated protein that is phosphorylated at a casein kinase II site and reportedly binds calcium. Based on these properties, it has been hypothesized that lymphoid form of the 52-kDa phosphoprotein protein may play a role in lymphocyte signal transduction. We show that alternatively spliced mRNA are expressed from this gene in nonlymphoid cell lines (myocytes, stromal cells, fibroblasts). These cell lines do not express the 1.6-kb lymphoid cell-specific transcript. Instead, mRNA of 2.0 and 2.8 kb are detected in varying abundance. A full-length 2.0-kb cDNA has been cloned and sequenced from the BMS2 stromal cell line by conventional screening and polymerase chain reaction-based methods. This cDNA clone, designated S37, has a single open reading frame encoding a 328 amino acid peptide. The nucleotide sequence of the S37 stromal cell cDNA is identical to that of the lymphocyte derived pp52 cDNA from the 3' poly(A) tail to the codon encoding the amino acid at residue 24. This region of the S37 cDNA clone encodes a protein that is identical to that encoded by the lymphoid pp52 cDNA and includes a casein kinase II phosphorylation site. However, the two clones differ in their 5' nucleotide sequence and their NH3 terminal amino acid sequence. This organization is consistent with alternative exon utilization. These results suggest that tissue-specific control mechanisms are used to generate different forms of lymphoid form of the 52-kDa phosphoprotein mRNA in lymphoid cells versus mesoderm-derived, nonlymphoid cell lineages.

Alternative Splicing↗
PubMed1993

Human lymphocyte-specific pp52 gene is a member of a highly conserved dispersed family.

For a better understanding of genes that potentially function in B lymphocyte cell signaling, we isolated the human genomic counterpart of the murine pp52 or LSP1 gene. We unexpectedly found that the human pp52 gene is one of four closely related loci. Representative cosmids from each of the four family members were isolated and chromosomally localized by fluorescence in situ hybridization. Nucleotide sequence was obtained from an exon common to each locus and demonstrated very close similarity among all four loci. Two of the four loci harbored dysfunctional frameshift mutations or premature translation stop sites. The exon of one locus was flanked by an 80-bp perfect inverted repeat, suggesting that it may have originated through a looped intermediate DNA structure. Through a series of cDNA hybridization studies and nucleotide sequence analyses we were able to unambiguously link the lymphocyte-expressed gene to the locus mapped to chromosome 11p15.5. This same chromosomal band has been involved in tumor-related chromosomal translocations found in chronic lymphocytic leukemia.

Animals↗
PubMed1993

Isolation and chromosomal mapping of the human immunoglobulin-associated B29 gene (IGB).

The B29 gene encodes a B-cell-specific membrane protein in the immunoglobulin antigen receptor complex. B29 is a crucial member of this receptor complex and is believed to function as an effector of signal transduction in a manner analogous to that of the CD3 components of the T cell antigen receptor. We have isolated a full-length human B29 cDNA clone by using a murine B29 cDNA probe. We show that there is an extremely high degree of evolutionary conservation between the human and mouse proteins, particularly in the transmembrane and intracytoplasmic regions, where the identity is 96%. In addition, the intracytoplasmic region in both proteins contains an identical peptide motif that is present in a number of molecules involved in lymphocyte activation. Genomic Southern blot analysis of human cell lines hybridized with both murine and human B29 cDNAs gives patterns consistent with a single-copy gene occupying a small region of the genomic sequence. Using human B29 cosmid DNA, we have localized the B29 gene to human chromosome 17q23 via fluorescence in situ hybridization. B29 is the first gene localized to this area of the genome. Interestingly, a subset of human B cell chronic lymphocytic leukemias (CLL) has translocations in this locus on chromosome 17.

Amino Acid Sequence↗
PubMed1993

Interleukin-5 (IL-5) and IL-6 define two molecularly distinct pathways of B-cell differentiation.

Interleukin-5 (IL-5) and IL-6 have both been reported to act as B-cell differentiation factors by stimulating activated B cells to secrete antibody. However, it has not been possible to directly compare the effects of these two lymphokines because of the lack of a suitable B-cell line capable of responding to both. We have identified a clonal, inducible B-cell lymphoma, CH12, that has this property. Both IL-5 and IL-6 can independently stimulate increases in steady-state levels of immunoglobulin and J-chain mRNA and proteins, and they both induce the differentiation of CH12 into high-rate antibody-secreting cells. Nevertheless, there are significant differences in the activities of these two lymphokines. First, while IL-6 acts only as a differentiation factor, IL-5 also augments the proliferation of CH12 cells. Second, the differentiation stimulated by IL-5 but not by IL-6 is partially inhibited by IL-4. Inhibition of IL-5-induced differentiation was not at the level of IL-5 receptor expression, since IL-4 did not inhibit IL-5-induced proliferation. Third, IL-5 but not IL-6 stimulated increased mouse mammary tumor proviral gene expression in CH12 cells. These results demonstrate that while both IL-5 and IL-6 may act as differentiation factors for B cells, they induce differentiation by using at least partially distinct molecular pathways. Our results also establish that B cells characteristic of a single stage of development can independently respond to IL-4, IL-5, and IL-6.

Animals↗
PubMed1992

Membrane mu poly(A) signal and 3' flanking sequences function as a transcription terminator for immunoglobulin-encoding genes.

Developmentally regulated mechanisms involving alternative RNA splicing and/or polyadenylation, as well as transcription termination, are implicated in controlling the levels of secreted mu (mu s), membrane mu (mu m) and delta immunoglobulin (Ig) heavy chain mRNAs during B cell differentiation (mu gene encodes the mu heavy chain). Using expression vectors constructed with genomic DNA segments composed of the mu m polyadenylation signal region, we analyzed poly(A) site utilization and termination of transcription in stably transfected myeloma cells and in murine fibroblast L cells. We found that the gene segment containing the mu m poly(A) signals, along with 536 bp of downstream flanking sequence, acted as a transcription terminator in both myeloma cells and L cell fibroblasts. Neither a 141-bp DNA fragment (which directed efficient polyadenylation at the mu m site), nor the 536-bp flanking nucleotide sequence alone, were sufficient to obtain a similar regulation. This shows that the mu m poly(A) region plays a central role in controlling developmentally regulated transcription termination by blocking downstream delta gene expression. Because this gene segment exhibited the same RNA processing and termination activities in fibroblasts, it appears that these processes are not tissue-specific.

Alternative Splicing↗
PubMed1992

Prevalence, regional distribution and control of blowfly strike in England and Wales.

The prevalence and control of blowfly strike in England and Wales was investigated by a postal survey of 2451 sheep farmers, divided into five regions, who were asked about the blowfly seasons of 1988 and 1989. These were important years for the control of blowfly strike because the number of compulsory dips for the control of sheep scab was reduced from two to one in 1989. The response rate was 74.2 per cent. A larger proportion of farmers in the south west and south east reported strike (90 per cent), than in the north of England (60 per cent). The proportion of sheep with strike showed a similar regional variation (0.7 per cent in the north of England to 2.8 per cent in the south west). Dipping was the most common method of blowfly control, followed by tail amputation, dagging, spraying and cyromazine. Twenty per cent of farmers reported reducing the frequency of dipping in 1989, and of those 20 per cent increased the frequency of spraying and 20 per cent used cyromazine.

Administration, Topical↗
PubMed1992

The IRG-47 gene is IFN-gamma induced in B cells and encodes a protein with GTP-binding motifs.

The murine pre-B cell line 70Z/3 has been studied extensively as a model system for B cell differentiation induced by cytokines and mitogens. IFN-gamma treatment of 70Z/3 pre-B cells activates Ig kappa L chain gene expression, resulting in the appearance of surface IgM characteristic of B cells. We have isolated and characterized a new cDNA clone, called IRG-47, whose mRNA is transiently elevated up to 30-fold at 4 to 6 h after IFN-gamma induction of 70Z/3 pre-B cells. The IFN-gamma induction of IRG-47 mRNA occurs in all pre-B and in most B lineage cell lines examined but is only induced in three cell lines tested from other lineages. Activation of IRG-47 gene transcription appears to account for the rapid increase in IRG-47 mRNA after induction. Transcription of the IRG-47 gene is down-regulated 10 h postinduction at a time when the level of IRG-47 mRNA is also declining. The complete sequence of the IRG-47 cDNA clone is predicted to encode a 47-KDa protein which, although unique in its sequence, bears resemblance to a number of nucleotide-binding proteins. The IRG-47 coding sequence contains all three highly conserved peptide motifs in the appropriate spacing characteristic of guanine nucleotide-binding proteins.

Amino Acid Sequence↗
PubMed1992

B29 gene products complex with immunoglobulins on B lymphocytes.

B29 is a B-lineage-specific gene predicted from sequence information to be a transmembrane member of the immunoglobulin (Ig) superfamily, with a single extracellular Ig-like domain. Its presumptive cytoplasmic region contains a peptide motif present in CD3 and other molecules involved in lymphocyte activation. Affinity-purified goat antibodies were prepared to a TrpE fusion protein of B29 and used to study B29 expression on lymphoid cells. The antiserum precipitated surface-labeled heterodimers from B lymphoma cells. One was 65-88 kDa (unreduced) or 36-47 plus 32-34 kDa (reduced) by SDS/PAGE analysis, regardless of detergent. A smaller heterodimer was detected only with Triton detergent extraction. IgM molecules were coprecipitated by the B29 antiserum when the weak detergent digitonin was used. In addition, cocapping experiments revealed that most B29 molecules codistribute with Ig on the cell surface. Although early B-lineage cells and plasma cells contain B29 mRNA, surface expression was detectable only on B cells that had significant amounts of surface Ig. The surface expression was B-lineage-specific and included cells from mutant xid mice and B-cell lines representing mu, delta, gamma, and alpha heavy-chain isotypes and both kappa and lambda light-chain types. The density of surface B29 protein correlated directly with surface mu heavy-chain density on subclones of a B-cell lymphoma and lipopolysaccharide-stimulated pre-B cells. These findings show that B29 is covalently linked in a heterodimer and are consistent with a recently proposed model of surface Ig complexes.

Animals↗
PubMed1992

Pulsatile activation of the hypothalamic-pituitary-adrenal axis during major surgery.

To examine the response of the hypothalamic-pituitary-adrenal (HPA) axis to severe surgical stress, we measured the immunoreactive plasma levels of corticotropin-releasing hormone (CRH), corticotropin, cortisol, arginine-vasopressin (AVP), atrial natriuretic factor (ANF), neuropeptide Y (NPY), interleukin-1 (IL-1), IL-6, interferon gamma (INF), and tumor necrosis factor-alpha (TNF-alpha) in eight patients with Zollinger-Ellison syndrome (ZES) or mediastinal parathyroid carcinoma, all undergoing major surgery with a standardized anesthetic technique. Blood samples were drawn the morning before surgery, every 10 to 30 minutes throughout surgery (average, 308.7 +/- 15 minutes), and every morning for the next 4 postoperative days (POD). During surgery, plasma CRH concentrations were slightly but not significantly elevated compared with those before surgery and with those of the next 4 POD. However, the values were within the normal range (less than 2.2 pmol/L) and showed 8.9 +/- 0.6 pulses (one pulse every 34.7 +/- 1.6 minutes). Plasma corticotropin, on the other hand, was quite elevated, but was also released in a pulsatile fashion during the surgical procedure (one pulse every 36.7 +/- 1.6 minutes). Most of these secretory episodes of corticotropin were temporally related to those of CRH. Corticotropin returned to basal levels on the first POD and remained so for all 4 POD. Plasma cortisol concentrations increased steadily during surgery and remained elevated the first POD. Cortisol showed 6.2 +/- 1.1 pulses during the operative sampling period (one pulse every 71.8 +/- 13 minutes). Plasma AVP concentrations were also markedly elevated during surgery, but individual secretory pulses were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines↗
PubMed1992

Development of an attractive target for the sheep blowfly Lucilia sericata.

Coloured, odour-baited, sticky targets, designed to catch the sheep blowfly Lucilia sericata Meigen are described and the results of field trials are presented. The number of L. sericata caught by the targets was positively related to target surface area and was dependent on target colour. The performance of the coloured targets is described by a model in which catch is related negatively to reflectivity in the 300-450 nm (ultra-violet/blue) band of the spectrum and positively to the reflectivity in the 450-580 nm (blue-green-yellow) band. Of the Lucilia blowflies caught by the targets, 13-16% were L.sericata and 72-75% of the L.sericata were female. The number of L.sericata caught appeared to be positively related to the availability of sheep over a relatively localized area and showed a marked decline following insecticidal dipping of sheep. The further development of targets and the implications of the results for L.sericata control are discussed.

Animals↗
PubMed1992

Lipopolysaccharide-induced NF-kappa B activation in mouse 70Z/3 pre-B lymphocytes is inhibited by mevinolin and 5'-methylthioadenosine: roles of protein isoprenylation and carboxyl methylation reactions.

We show that both the lipopolysaccharide (LPS)-induced activation of NF-kappa DNA binding and kappa gene expression are blocked by treating murine pre-B lymphocyte 70Z/3 cells with 5'-methylthioadenosine (MTA), an inhibitor of several S-adenosylmethionine-dependent methylation reactions. We further show that the LPS-induced incorporation of radioactivity from [methyl-3H]methionine into methyl ester-like linkages on a group of membrane polypeptides is also inhibited by MTA treatment, suggesting the involvement of protein methylation reactions in the LPS signal transduction pathway. We also find that NF-kappa B and kappa gene activation in LPS-treated 70Z/3 cells is blocked by mevinolin, an inhibitor that prevents protein isoprenylation. Interestingly, mevinolin-treated cells also exhibited a marked reduction in the methylation of membrane proteins. Neither MTA nor mevinolin significantly inhibited NF-kappa B activation by phorbol myristate acetate, suggesting that these agents act early in signal transduction. These results provide the first evidence that carboxyl methylated and/or isoprenylated proteins play an essential role in the LPS-signaling pathway.

Adenosine↗