Relationships between body condition score, body weight and body measurements in alpacas.

Background: The nutritional status in alpacas is often masked by their dense fibre coat. Its assessment is commonly approached by different body condition scores (BCS) that rely on manual palpation of defined anatomical regions. However, BCS is an important diagnostic tool to aid recognition of diseased South American camelids (SACs) and low BCS has been associated with conditions like anaemia and neutrophilia.

Inactivation of Lgt allows systematic characterization of lipoproteins from Listeria monocytogenes.

Lipoprotein anchoring in bacteria is mediated by the prolipoprotein diacylglyceryl transferase (Lgt), which catalyzes the transfer of a diacylglyceryl moiety to the prospective N-terminal cysteine of the mature lipoprotein. Deletion of the lgt gene in the gram-positive pathogen Listeria monocytogenes (i) impairs intracellular growth of the bacterium in different eukaryotic cell lines and (ii) leads to increased release of lipoproteins into the culture supernatant. Comparative extracellular proteome analyses of the EGDe wild-type strain and the Delta lgt mutant provided systematic insight into the relative expression of lipoproteins.

Mutations of arginine residues within the 146-KKRRK-150 motif of the ActA protein of Listeria monocytogenes abolish intracellular motility by interfering with the recruitment of the Arp2/3 complex.

The recruitment of actin to the surface of intracellular Listeria monocytogenes and subsequent tail formation is dependent on the expression of the bacterial surface protein ActA. Of the different functional domains of ActA identified thus far, the N-terminal region is absolutely required for actin filament recruitment and intracellular motility. Mutational analysis of this domain which abolished actin recruitment by intracellular Listeria monocytogenes identified two arginine residues within the 146-KKRRK-150 motif that are essential for its activity.

The role of the bacterial membrane protein ActA in immunity and protection against Listeria monocytogenes.

ActA, an essential virulence factor of Listeria monocytogenes, is an integral membrane protein that is required for intracellular motility, cell-to-cell spread, and rapid dissemination of the bacteria in the infected host. To reveal cytotoxic T cell responses against ActA we introduced a recombinant soluble form of ActA into the MHC class I-processing compartment of APC using a variant of listeriolysin mutated within its immunodominant MHC class I epitope. With this experimental system we demonstrate that T cells are induced against ActA during a sublethal infection with L.

Attenuated Listeria monocytogenes carrier strains can deliver an HIV-1 gp120 T helper epitope to MHC class II-restricted human CD4+ T cells.

Listeria monocytogenes is a facultative intracellular pathogen which, following uptake by macrophages, escapes from the phagosome and replicates in the cytoplasm. This property has been exploited using recombinant L. monocytogenes as a carrier for the intracytoplasmic expression of antigens when MHC class I-restricted cytotoxic T lymphocyte responses are required.

Oral somatic transgene vaccination using attenuated S. typhimurium.

An attenuated strain of S. typhimurium has been used as a vehicle for oral genetic immunization. Eukaryotic expression vectors containing truncated genes of ActA and listeriolysin--two virulence factors of Listeria monocytogenes--have been used to transform S.

Crystal structure of the phosphatidylinositol-specific phospholipase C from the human pathogen Listeria monocytogenes.

The X-ray crystal structure of the phosphatidylinositol-specific phospholipase C (PI-PLC) from the human pathogen Listeria monocytogenes has been determined both in free form at 2.0 A resolution, and in complex with the competitive inhibitor myo-inositol at 2.6 A resolution.

The ActA polypeptides of Listeria ivanovii and Listeria monocytogenes harbor related binding sites for host microfilament proteins.

The surface-bound ActA polypeptide of the intracellular bacterial pathogen Listeria monocytogenes acts as a nucleator protein, generating the actin cytoskeleton around intracellularly motile bacteria. In this work, we examined the functional similarity of ActA from Listeria ivanovii (iActA) ATCC 19119 to its L. monocytogenes counterpart.

A focal adhesion factor directly linking intracellularly motile Listeria monocytogenes and Listeria ivanovii to the actin-based cytoskeleton of mammalian cells.

The surface-bound ActA polypeptide of the intracellular bacterial pathogen Listeria monocytogenes is the sole listerial factor needed for recruitment of host actin filaments by intracellularly motile bacteria. Here we report that following Listeria infection the host vasodilator-stimulated phosphoprotein (VASP), a microfilament- and focal adhesion-associated substrate of both the cAMP- and cGMP-dependent protein kinases, accumulates on the surface of intracytoplasmic bacteria prior to the detection of F-actin 'clouds'. VASP remains associated with the surface of highly motile bacteria, where it is polarly located, juxtaposed between one extremity of the bacterial surface and the front of the actin comet tail.

The effects of 5'-capping, 3'-polyadenylation and leader composition upon the translation and stability of mRNA in a cell-free extract derived from the yeast Saccharomyces cerevisiae.

A new modular expression system was developed to direct the in vitro synthesis of defined transcripts that were used as templates for translation in yeast cell-free extracts. The system was used to examine the influence of 5'-capping, 3'-polyadenylation and leader sequence upon the translation and stability of the synthetic Tn9 cat (chloramphenicol acetyl transferase), yeast PGK (phosphoglycerate kinase) and yeast HSP26 (heat-shock protein 26) mRNAs. The addition of a methylated cap (m7Gppp) or of a poly(A) tail enhanced translation and stabilized the mRNA.

Differential gene expression from the Escherichia coli atp operon mediated by segmental differences in mRNA stability.

The atp operon of Escherichia coli directs synthesis rates of protein subunits that are well matched to the requirements of assembly of the membrane-bound H(+)-ATPase (alpha 3 beta 3 gamma 1 delta 1 epsilon 1a1b2c10-15). Segmental differences in mRNA stability are shown to contribute to the differential control of atp gene expression. The first two genes of the operon, atpl and atpB, are rapidly inactivated at the mRNA level.

Independent and coupled translational initiation of atp genes in Escherichia coli: experiments using chromosomal and plasmid-borne lacZ fusions.

The translational initiation rates directed by the translational initiation regions (TIRs) of the atpB, atpH, atpA and atpG genes of Escherichia coli were investigated using lacZ fusions present on plasmids as well as integrated into the chromosome. This was the first investigation of the translational efficiency of the atpB gene, whose unfused product (subunit a) can be toxic to the cell. The specific mRNA levels, rates of in vivo protein synthesis and beta-galactosidase activities encoded by the atp::lacZ fusions were compared in order to obtain valid estimates of relative translation rates.