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C Daly

Publications and source records attributed to C Daly.

At least 73 records · Page 4Linked to original sources
PubMed1995

Characterization of plasmid-encoded citrate permease (citP) genes from Leuconostoc species reveals high sequence conservation with the Lactococcus lactis citP gene.

The citrate permease determinant (citP) in several Leuconostoc strains was demonstrated to be plasmid encoded by curing experiments and hybridization studies with a DNA fragment containing the citP gene from Lactococcus lactis subsp. lactis biovar diacetylactis NCDO176. Cloning and nucleotide sequence analysis of Leuconostoc lactis NZ6070 citP revealed almost complete identity to lactococcal citP.

Amino Acid Sequence↗
PubMed1994

The impact of biotechnology on the dairy industry.

The review focusses on the use of genetic techniques to manipulate bacteria that are important to the dairy industry. Both classical and molecular approaches have been used to improve strains involved in yoghurt and cheese production. Examples are provided of methods for; increasing efficiency of substrate conversion, regulating the production of flavour enhancing metabolites, and developing starter cultures resistant to bacteriophage and bacteriocin attack. The possible applications of these systems are discussed.

Journal Article↗
PubMed1994

Antiglomerular basement membrane disease: the long-term pulmonary outcome.

We have evaluated long-term pulmonary function in 14 patients who were treated for anti-glomerular basement membrane disease at our institution during the last 17 years. Eight of these patients had evidence of pulmonary involvement, as manifested by hemoptysis, pulmonary infiltrates on chest x-ray film, or anemia. These patients were compared with a control group of 15 patients who had renal disease and who were matched for degree and duration of renal disease, age, smoking history, and method of renal replacement. The following variables were measured in each patient: forced vital capacity, forced expiratory volume in 1 minute, vital capacity, total lung capacity, residual volume, functional residual capacity, single-breath carbon monoxide transfer factor, and single-breath carbon monoxide transfer factor corrected for alveolar volume (KCO). These patients also participated in a graded exercise test and measurements of oxygen uptake, carbon dioxide production, minute ventilation, and oxygen saturation were taken. Patients with anti-glomerular basement membrane disease and a prior history of pulmonary hemorrhage had a significantly reduced KCO (46% +/- 10% v 68.7% +/- 14.7%) compared with the control group. There was no difference in any of the other measured parameters.

Adult↗
PubMed1994

Nucleotide sequence and structural organization of the small, broad-host-range plasmid pCI411 from Leuconostoc lactis 533.

The nucleotide sequence of the Leuconostoc lactis 533 cryptic plasmid pCI411 (2926 bp) was determined. Analysis revealed the presence of three open reading frames (ORFs). ORF 1 was capable of encoding a 24.9 kDa peptide which shared homology with the replication initiation protein (RepB) from a number of Gram-positive rolling circle plasmids. ORF 2 could encode a peptide of 6.6 kDa which was homologous to the RepC protein of the lactococcal plasmid pWV01. A function could not be assigned to ORF 3, which was capable of encoding a 12.1 kDa peptide. Transcription-translation analysis indicated the presence of three peptides of the predicted molecular masses. A putative double strand origin of replication (DSO) was identified which showed strong similarity with the DSO of a number of Gram-positive plasmids including pE194 from Staphylococcus. Structural analysis identified a number of direct and indirect repeats in addition to putative recombination-specific sites (RSA and RSB) in the non-coding region of pCI411. The observed characteristics suggest that this plasmid replicates using the rolling circle mechanism. pCI411, which could be introduced into Leuconostoc, Lactococcus, Streptococcus, Lactobacillus and Bacillus is the first plasmid from the genus Leuconostoc to be characterized in such detail.

Amino Acid Sequence↗
PubMed1994

Isolation from food sources, of lactic acid bacteria that produced antimicrobials.

The potential of lactic acid bacteria, isolated from a variety of foods, to inhibit indicators representative of spoilage and pathogenic bacteria associated with food products was examined. Fruit and vegetables were a poor source of lactic acid bacteria but large numbers were readily isolated on MRS agar from cheese, milk and meat samples. Approximately 1000 isolates from each of the food samples were examined by the deferred antagonism procedure to determine their ability to inhibit Staphylococcus aureus, Listeria innocua and Pseudomonas fragi. Listeria innocua was the bacterium predominantly inhibited by isolates from the cheese, milk and meats, but antagonism was also observed to a lesser extent against the other indicators. The only inhibition observed for isolates from vegetable material was directed against Staph. aureus. The majority of inhibitor producers were effective against only one of the indicators but a small number were isolated which inhibited two or three.

Animals↗
PubMed1994

A study of the microbiological status of Irish farmhouse cheeses with emphasis on selected pathogenic and spoilage micro-organisms.

Ninety-six 25 g samples from 25 Irish farmhouse cheeses, two Irish non-farmhouse cheeses and four foreign cheeses were evaluated for the presence of a variety of micro-organisms, namely, coliforms, faecal streptococci, Staphylococcus aureus, yeasts, moulds, salmonellas and shigellas. Seventeen cheeses, i.e. the soft and semi-soft types, were examined for Listeria monocytogenes. Most of the farmhouse cheeses are currently manufactured from raw milk, but some producers now use heat-treated milk. The incidence of coliforms and faecal coliforms was higher in soft, semi-soft and semi-hard cheeses than in hard types. High levels of contamination by faecal streptococci and non-pathogenic (coagulase-negative) Staph. aureus prevailed in a high proportion of the cheeses. Pathogenic (coagulase-positive) staphylococci, however, were also isolated from 50% of the cheeses, some of which were manufactured from pasteurized milk. Yeasts were found mainly in unpasteurized varieties, especially in the category of soft cheeses. Moulds were isolated from five non-mould-ripened cheeses, as well as from mould-ripened varieties. Salmonellas, shigellas and Listeria monocytogenes were not detected after direct enrichment.

Cheese↗
PubMed1994

Effect of genetically modifying the lactococcal proteolytic system on ripening and flavor development in cheddar cheese.

THREE BATCHES OF SIX CHEDDAR CHEESES WERE MANUFACTURED BY USING THE FOLLOWING LACTOCOCCAL STRAINS: (i) UC317 as a control; (ii) JL3601, a proteinase-negative derivative of UC317 transformed with high-copy-number plasmid pCI3601 containing the cloned proteinase gene complex from UC317; (iii) AM312, a proteinase-negative derivative of UC317 transformed with plasmid pMG36enpr containing the neutral proteinase gene from Bacillus subtilis; (iv) AC322, JL3601 transformed with pMG36enpr; (v) AC311, UC317 transformed with plasmid pNZ1120, which contains the aminopeptidase N (pepN) gene from Lactococcus lactis subsp. lactis MG1363; and (vi) AC321, JL3601 transformed with pNZ1120. Organoleptic and chemical analyses indicated that (i) the control cheeses, which were made with UC317, were of the highest quality; (ii) cheeses made with strains harboring pCI3601 in addition to either pMG36enpr (AC322) or pNZ1120 (AC321) did not ripen in a significantly different manner than cheeses made with AM312 (containing only pMG36enpr) or AC311 (containing only pNZ1120), respectively; (iii) cheeses made with strains that overproduce pepN did not have improved body, texture, and flavor characteristics; and (iv) cheeses made with strains harboring the neutral proteinase from B. subtilis (AM312 and AC322) underwent greatly accelerated proteolysis.

Journal Article↗
PubMed1994

Molecular characterization of lactococcal bacteriophage Tuc2009 and identification and analysis of genes encoding lysin, a putative holin, and two structural proteins.

Bacteriophage Tuc2009 is a temperate bacteriophage with a small isometric head and is isolated from Lactococcus lactis subsp. cremoris UC509. The phage genome is packaged by a headful mechanism, giving rise to circularly permuted molecules with terminal redundancy. The unit genome size is approximately 39 kb. A map of the phage genome on which several determinants could be localized was constructed: pac, the site of initiation of DNA packaging; lys (1,287 bp), specifying the phage lysin; S (267 bp), specifying a putative holin; and mp1 (522 bp) and mp2 (498 bp), each specifying one of the phage's structural proteins. lys, S, mp1, and mp2 were further characterized. lys and S are partially overlapping and appear to be part of one operon. The lysin shows homology to the lysins of the Streptococcus pneumoniae phages Cp-9, Cp-1, and Cp-7. The putative holin, which is thought to be involved in the release of lysin from the cytoplasm, contains two strongly hydrophobic presumptive transmembrane domains and a highly charged C-terminal domain.

Amino Acid Sequence↗
PubMed1994

Identification of int and attP on the genome of lactococcal bacteriophage Tuc2009 and their use for site-specific plasmid integration in the chromosome of Tuc2009-resistant Lactococcus lactis MG1363.

The DNA sequence of the int-attP region of the small-isometric-headed lactococcal bacteriophage Tuc2009 is presented. In this region, an open reading frame, int, which potentially encodes a protein of 374 amino acids, representing the Tuc2009 integrase, was identified. The nucleotide sequence of the bacteriophage attachment site, attP, and the sequences of attB, attL, and attR in the lysogenic host Lactococcus lactis subsp. cremoris UC509 were determined. A sequence almost identical to the UC509 attB sequence was found to be present in the plasmid-free Tuc2009-resistant L. lactis subsp. cremoris MG1363. This site could be used for the site-specific integration of a plasmid carrying the Tuc2009 int-attP region in the chromosome of MG1363, thereby demonstrating that the application of chromosomal insertion vectors based on bacteriophage integration functions is not limited to the prophage-cured original host strain of the phage.

Amino Acid Sequence↗
PubMed1993

Identification and sequence analysis of the replication region of the phage resistance plasmid pCI528 from Lactococcus lactis subsp. cremoris UC503.

The replication region of the phage resistance plasmid pCI528 from Lactococcus lactis subsp. cremoris UC503 was localised to within a 10-kb HindIII restriction fragment. A 6.3-kb BglII-HindIII subclone of this fragment, cloned into a replication probe vector, allowed replication in Lactococcus but not in Bacillus or Lactobacillus. Sequence analysis revealed an ORF of 1152 bp preceded by a putative ori region containing a 22-bp sequence tandemly repeated three and three-quarter times, a second smaller direct repeat and two inverted repeats. Extensive homology was observed with the well characterised replication region of the small cryptic plasmid pCI305 (Hayes, F., Vos, P., Fitzgerald, G.F., deVos, W. and Daly, C. Plasmid 25, 16-26).

Amino Acid Sequence↗
PubMed1993

The use of reverse transcriptase-polymerase chain reaction (RT-PCR) to investigate specific gene expression in multidrug-resistant cells.

Expression of specific genes at the level of mRNA can be studied using techniques such as Northern blot, slot/dot blot, RNase protection assay, in situ hybridisation and RT-PCR. In this article these methods of analysis are compared; RT-PCR offers higher levels of specificity and sensitivity than traditional methods of RNA analysis and as such has become the method of choice for the study of gene expression. The RT-PCR technique is described in detail with sections dealing with RNA extraction, choice of primers (including the use of cDNA sequence data bases), PCR and RT-PCR protocols in addition to the limitations of the method. The study of one particular mRNA transcript (MDR1) using RT-PCR is discussed in detail. Recently described methods for quantitation of PCR products are discussed. Quantitative PCR would appear to offer a method of studying gene expression in a more extensive way than has been possible to date.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

ScrFI restriction-modification system of Lactococcus lactis subsp. cremoris UC503: cloning and characterization of two ScrFI methylase genes.

Two genes from the total genomic DNA of dairy starter culture Lactococcus lactis subsp. cremoris UC503, encoding ScrFI modification enzymes, have been cloned and expressed in Escherichia coli. No homology between the two methylase genes was detected, and inverse polymerase chain reaction of flanking chromosomal DNA indicated that both were linked on the Lactococcus genome. Neither clone encoded the cognate endonuclease. The DNA sequence of one of the methylase genes (encoded by pCI931M) was determined and consisted of an open reading frame 1,170 bp long, which could encode a protein of 389 amino acids (M(r), 44.5). The amino acid sequence contained the highly characteristic motifs of an m5C methylase. Extensive regions of homology were observed with the methylases of NlaX, EcoRII, and Dcm.

Amino Acid Sequence↗
PubMed1993

Analysis of a region from the bacteriophage resistance plasmid pCI528 involved in its conjugative mobilization between Lactococcus strains.

A 10-kb HindIII fragment of pCI528 cloned into the nonconjugative shuttle vector pCI3340 could be transferred by conjugative mobilization from Lactococcus lactis subsp. lactis MG1363, whereas other HindIII fragments of pCI528 or the vector alone were nonmobilizable. Subcloning of this 10-kb region identified a 4.4-kb BglII-EcoRI fragment which contained all the DNA essential for transfer. Sequence analysis of a 2-kb region within this 4.4 kb-segment revealed a region rich in inverted repeats and two potential overlapping open reading frames, one of which demonstrated homology to mobilization proteins of two nonconjugative staphylococcal plasmids.

Amino Acid Sequence↗
PubMed1993

Double-stranded RNA activates novel factors that bind to the interferon-stimulated response element.

Infection of cells with adenovirus or transfection of cells with double-stranded RNA (dsRNA) activates transcription of the alpha/beta interferon-stimulated genes (ISGs). Induction of ISG expression by adenovirus appears to be mediated through the same DNA target that is responsive to alpha/beta interferons, the interferon-stimulated response element (ISRE). Transcriptional induction by alpha/beta interferons has been shown previously to be mediated by the activation of a latent cytoplasmic transcription factor, ISGF3, that translocates to the nucleus and binds to the ISRE. However, ISG expression induced by adenovirus or dsRNA appears to be mediated by unique dsRNA-activated factors (DRAFs) that bind to the ISRE. The activation of these preexisting factors by dsRNA does not require new protein synthesis. Two DRAFs, DRAF1 and DRAF2, have been identified in our studies as ISRE-binding complexes in gel mobility shift assays. The ISRE-binding specificity of DRAF1 is similar to that of ISGF3; however, the ISRE-binding specificity of DRAF2 is distinct. Activation of DRAF1 and DRAF2 is independent of interferon action since it occurs in cells that are nonresponsive to interferon and in cells that lack the alpha/beta interferon locus. The activation pathway of DRAF1 and DRAF2 is blocked by the protein kinase inhibitors staurosporine and genistein. This is analogous to the interferon signal transduction pathway and suggests that phosphorylation, possibly tyrosine phosphorylation, is involved in activation of these factors.

Actins↗
PubMed1993

The contribution of lactococcal starter proteinases to proteolysis in cheddar cheese.

The contribution of the lactococcal proteinase to proteolysis and flavor development in Cheddar cheese was investigated using the starter strains Lactococcus lactis ssp. lactis UC317, its proteinase-negative derivative FH041, and variants of UC317 modified in proteinase production, location, and specificity. Lactococcus lactis ssp. lactis FH041 was transformed by electroporation with plasmids pCI3601, pCI3602, or pNZ521. Plasmids pCI3601 and pCI3602 harbor the cloned proteinase genes of L. lactis ssp. lactis UC317 on a high copy number vector and, as such, encode an increased concentration of cell wall-associated and secreted enzymes, respectively. Plasmid pNZ521 contains the cloned proteinase genes from Lactococcus lactis ssp. cremoris SK11. Assessment of proteolysis and flavor development in Cheddar cheese made with these strains revealed that starter proteinases are required for the accumulation of small peptides and free amino acids in Cheddar cheese. Proteolysis was not enhanced by an approximately threefold increase in concentration of the lactococcal proteinase. The strain in which the proteinase remained attached to the cell wall appeared to contribute more to proteolysis than the strain that secreted the enzyme. Water-soluble peptides unique to Lactococcus lactis ssp. cremoris SK11 and L. lactis ssp. lactis UC317 were detected by PAGE and HPLC, respectively. Sensory evaluation showed that the flavors of all cheeses made with proteinase-positive starters were similar, but cheeses made with proteinase-negative starters lacked flavor.

Amino Acids↗
PubMed1992

Tyrosine phosphorylation is required for activation of an alpha interferon-stimulated transcription factor.

The signal transduction pathway of alpha interferon utilizes tyrosine phosphorylation to transmit a signal generated at the cell surface to the transcriptional machinery in the nucleus. Activation of the interferon pathway initiates with the binding of alpha interferon to its cell surface receptor. The ligand-receptor complex signals the activation of a latent cytoplasmic transcription factor. The active form of the interferon-stimulated gene factor (ISGF3) is phosphorylated on tyrosine residues. ISGF3 subsequently translocates to the nucleus and binds to a DNA sequence, the interferon-stimulated response element, found within the promoter of inducible genes. ISGF3 is a multicomponent factor consisting of four proteins of 113 kDa, 91 kDa, 84 kDa, and 48 kDa. Three proteins consistent with sizes of 113 kDa, 91 kDa, and 84 kDa copurify with ISGF3 and are phosphorylated on tyrosine residues after stimulation by alpha interferon. Tyrosine phosphorylation is essential for activation of ISGF3. Genistein, a tyrosine kinase inhibitor, blocks the appearance of ISGF3 and blocks the transcriptional stimulation of interferon-induced genes. This study shows that tyrosine phosphorylation provides a link between the interferon-receptor complex at the plasma membrane and specific activation of gene expression in the nucleus.

Base Sequence↗