Weight loss is not mandatory for exercise-induced effects on health indices in females with metabolic syndrome

The aim of this study was to investigate the impact of moderate aerobic training on functional, anthropometric, biochemical, and health-related quality of life (HRQOL) parameters on women with metabolic syndrome (MS). Fifteen untrained women with MS performed moderate aerobic training for 15 weeks, without modifications of dietary behaviours. Functional, anthropometric, biochemical, control diet record and HRQOL parameters were assessed before and after the training. Despite body weight maintenance, the patients presented decreases in waist circumference (P = 0.001), number of MS components (P = 0.014), total cholesterol (P = 0.049), HDL cholesterol (P = 0.004), LDL cholesterol (P = 0.027), myeloperoxidase activity (P = 0.002) and thiobarbituric acid-reactive substances levels (P = 0.006). There were no differences in total energy, carbohydrate, protein and lipid intake pre- and post-training. Furthermore, improvements in the HRQOL subscales of physical functioning (P = 0.03), role-physical (P = 0.039), bodily pain (P = 0.048), general health (P = 0.046) and social functioning scoring (P = 0.011) were reported. Despite the absence of weight loss, aerobic training induced beneficial effects on functional, anthropometric, biochemical and HRQOL parameters in women with MS.     

Legionella pneumophila requires polyamines for optimal intracellular growth

The Gram-negative intracellular pathogen Legionella pneumophila replicates in a membrane-bound compartment known as the Legionella-containing vacuole (LCV), into which it abundantly releases its chaperonin, HtpB. To determine whether HtpB remains within the LCV or reaches the host cell cytoplasm, we infected U937 human macrophages and CHO cells with L. pneumophila expressing a translocation reporter consisting of the Bordetella pertussisa denylate cyclase fused to HtpB. These infections led to increased cyclic AMP levels, suggesting that HtpB reaches the host cell cytoplasm. To identify potential functions of cytoplasmic HtpB, we expressed it in the yeast Saccharomyces cerevisiae, where HtpB induced pseudohyphal growth. A yeast-two-hybrid screen showed that HtpB interacted with S-adenosylmethionine decarboxylase (SAMDC), an essential yeast enzyme (encoded by SPE2) that is required for polyamine biosynthesis. Increasing the copy number of SPE2 induced pseudohyphal growth in S. cerevisiae; thus, we speculated that (i) HtpB induces pseudohyphal growth by activating polyamine synthesis and (ii) L. pneumophila may require exogenous polyamines for growth. A pharmacological inhibitor of SAMDC significantly reduced L. pneumophila replication in L929 mouse cells and U937 macrophages, whereas exogenously added polyamines moderately favored intracellular growth, confirming that polyamines and host SAMDC activity promote L. pneumophila proliferation. Bioinformatic analysis revealed that most known enzymes required for polyamine biosynthesis in bacteria (including SAMDC) are absent in L. pneumophila, further suggesting a need for exogenous polyamines. We hypothesize that HtpB may function to ensure a supply of polyamines in host cells, which are required for the optimal intracellular growth of L. pneumophila.     

Fellow travellers: a concordance of colonization patterns between mice and men in the North Atlantic region

Background

In the Calvin cycle of eubacteria, the dephosphorylations of both fructose-1, 6-bisphosphate (FBP) and sedoheptulose-1, 7-bisphosphate (SBP) are catalyzed by the same bifunctional enzyme: fructose-1, 6-bisphosphatase/sedoheptulose-1, 7-bisphosphatase (F/SBPase), while in that of eukaryotic chloroplasts by two distinct enzymes: chloroplastic fructose-1, 6-bisphosphatase (FBPase) and sedoheptulose-1, 7-bisphosphatase (SBPase), respectively. It was proposed that these two eukaryotic enzymes arose from the divergence of a common ancestral eubacterial bifunctional F/SBPase of mitochondrial origin. However, no specific affinity between SBPase and eubacterial FBPase or F/SBPase can be observed in the previous phylogenetic analyses, and it is hard to explain why SBPase and/or F/SBPase are/is absent from most extant nonphotosynthetic eukaryotes according to this scenario.

Results

Domain analysis indicated that eubacterial F/SBPase of two different resources contain distinct domains: proteobacterial F/SBPases contain typical FBPase domain, while cyanobacterial F/SBPases possess FBPase_glpX domain. Therefore, like prokaryotic FBPase, eubacterial F/SBPase can also be divided into two evolutionarily distant classes (Class I and II). Phylogenetic analysis based on a much larger taxonomic sampling than previous work revealed that all eukaryotic SBPase cluster together and form a close sister group to the clade of epsilon-proteobacterial Class I FBPase which are gluconeogenesis-specific enzymes, while all eukaryotic chloroplast FBPase group together with eukaryotic cytosolic FBPase and form another distinct clade which then groups with the Class I FBPase of diverse eubacteria. Motif analysis of these enzymes also supports these phylogenetic correlations.

Conclusions

There are two evolutionarily distant classes of eubacterial bifunctional F/SBPase. Eukaryotic FBPase and SBPase do not diverge from either of them but have two independent origins: SBPase share a common ancestor with the gluconeogenesis-specific Class I FBPase of epsilon-proteobacteria (or probably originated from that of the ancestor of epsilon-proteobacteria), while FBPase arise from Class I FBPase of an unknown kind of eubacteria. During the evolution of SBPase from eubacterial Class I FBPase, the SBP-dephosphorylation activity was acquired through the transition ??from specialist to generalist??. The evolutionary substitution of the endosymbiotic-origin cyanobacterial bifunctional F/SBPase by the two light-regulated substrate-specific enzymes made the regulation of the Calvin cycle more delicate, which contributed to the evolution of eukaryotic photosynthesis and even the entire photosynthetic eukaryotes.     

Salivary and serum procalcitonin and C-reactive protein as biomarkers of periodontitis in United States veterans with osteoarthritis or rheumatoid arthritis

Serum procalcitonin (ProCT) is elevated in response to bacterial infections, whereas high sensitivity C-reactive protein (hsCRP) is a nonspecific inflammatory marker that is increased by excess adipose tissue. We examined the efficacy of ProCT and hsCRP as biomarkers of periodontitis in the saliva and serum of patients with arthritis, which is characterized by variable levels of systemic inflammation that potentially can confound the interpretation of inflammatory biomarkers. Blood and unstimulated whole saliva were collected from 33 patients with rheumatoid arthritis (RA) and 50 with osteoarthritis (OA). Periodontal status was assessed by full mouth examination and patients were categorized as having no/mild, moderate or severe periodontitis by standard parameters. Salivary and serum ProCT and hsCRP concentrations were compared. BMI, diabetes, anti-inflammatory medications and smoking status were ascertained from the patient records. Differences between OA and RA in proportionate numbers of patients were compared for race, gender, diabetes, adiposity and smoking status. Serum ProCT was significantly higher in arthritis patients with moderate to severe and severe periodontitis compared with no/mild periodontitis patients. There were no significant differences in salivary ProCT or salivary or serum hsCRP in RA patients related to periodontitis category. Most of the OA and RA patients were middle aged or older, 28.9% were diabetic, 78.3% were overweight or obese, and slightly more than half were either current or past smokers. The OA and RA groups differed by race, but not gender; blacks and males were predominant in both groups. The OA and RA groups did not differ in terms of controlled or uncontrolled diabetes, smoking status or BMI. The RA patients had been prescribed more anti-inflammatory medication than the OA patients. Our results demonstrate that circulating ProCT is a more discriminative biomarker for periodontitis than serum hsCRP in patients with underlying arthritis. Any elevation in salivary and serum hsCRP due to periodontitis apparently was overshadowed by differences among these patients in factors that influence CRP, such as the extent of inflammation between RA and OA, the extent of adipose tissue, the use of anti- inflammatory medications and smoking status. Although our study showed no differences in salivary ProCT related to severity of periodontitis, this biomarker also may be useful with further refinement.     

Expression of Distinct Self-Incompatibility Specificities in Arabidopsis thaliana

The interplay of balancing selection within a species and rapid gene evolution between species can confound our ability to determine the functional equivalence of interspecific and intergeneric pairs of alleles underlying reproduction. In crucifer plants, mating specificity in the barrier to self-fertilization called self-incompatibility (SI) is controlled by allele-specific interactions between two highly polymorphic and co-evolving proteins, the S-locus receptor kinase (SRK) and its S-locus cysteine rich (SCR) ligand. These proteins have diversified both within and between species such that it is often difficult to determine from sequence information alone if they encode the same or different SI specificity. The self-fertile Arabidopsis thaliana was derived from an obligate outbreeding ancestor by loss of self-incompatibility, often in conjunction with inactivation of SRK or SCR. Nevertheless, some accessions of A. thaliana can express self-incompatibility upon transformation with an SRK–SCR gene pair isolated from its self-incompatible close relative A. lyrata. Here we show that several additional and highly diverged SRK/SCR genes from A. lyrata and another crucifer plant, Capsella grandiflora, confer self-incompatibility in A. thaliana, either as intact genes isolated from genomic libraries or after manipulation to generate chimeric fusions. We describe how the use of this newly developed chimeric protein strategy has allowed us to test the functional equivalence of SRK/SCR gene pairs from different taxa and to assay the functionality of endogenous A. thaliana SRK and SCR sequences.MATING reactions in plants, fungi, and animals are strongly influenced by molecular recognition machineries that act as gauges of genetic relatedness (Brown and Casselton 2001; Nasrallah 2005; Yamazaki and Beauchamp 2007). Many plants with hermaphroditic flowers have evolved inbreeding avoidance mechanisms, known as self-incompatibility (SI) systems. These systems are based on the ability of the female reproductive apparatus (the pistil) to discriminate among genetically distinct pollen grains, resulting in the failure of self-pollination despite functional female and male reproductive structures. In the Brassicaceae (crucifers), specific recognition of pollen by the epidermal cells of the stigma (a structure located at the tip of the pistil) is controlled by haplotypes of the S locus, and activation of the SI response leading to inhibition of pollen tube growth occurs if pollen and stigma are derived from plants that express the same S-locus haplotype (S haplotype). Within self-incompatible crucifer species, the number of S haplotypes and corresponding SI specificities is usually high, with >50 reported in some species (Watanabe et al. 2000), and SI dictates that self-incompatible plants are typically heterozygous and carry two S haplotypes. Each S haplotype is composed of two highly polymorphic genes that are the determinants of SI specificity in stigma and pollen (Stein et al. 1991; Schopfer et al. 1999). The S-locus receptor kinase (SRK) gene encodes a single-pass transmembrane serine/threonine kinase localized on the surface of stigma epidermal cells, and the S-locus cysteine-rich protein (SCR) gene encodes a small peptide localized in the pollen coat. SCR is the ligand for SRK and will bind to the extracellular domain of SRK (hereafter eSRK) only if both proteins are encoded by the same S-locus haplotype (Kachroo et al. 2001; Takayama et al. 2001; Chookajorn et al. 2004). The binding of SCR to its cognate eSRK triggers an intracellular phosphorylation cascade that results in pollen rejection by a poorly understood mechanism.A mechanistic understanding of the recognition phase of SI requires detailed structure–function analyses of SRK and SCR aimed at identifying the amino acid residues that determine their allele-specific interaction and explaining the puzzling dominance/recessive interactions exhibited by different SRK alleles in the heterozygous stigmas of self-incompatible plants (Hatakeyama et al. 2001; Mable et al. 2003; Prigoda et al. 2005). Such structure–function studies require an experimental system that allows efficient in vivo functional analysis of large numbers of SRK and SCR sequence variants generated in vitro by site-directed mutagenesis or domain swapping between proteins that determine different SI specificities. The recent transfer of the SI trait into Arabidopsis thaliana has established this species as a model organism for mechanistic and evolutionary studies of mating systems in crucifers (Nasrallah et al. 2002, 2004). However, to date, only one SI specificity, that which is determined by the Sb haplotype of A. lyrata, has been successfully introduced into A. thaliana and shown to alter the plant''s mating reaction from strict autogamy to full SI. To exploit fully the A. thaliana transgenic SI model, additional S haplotypes must be introduced into this species. In addition to facilitating mechanistic studies of the SRK–SCR interaction and dominance relationships, the expression of multiple SI specificities in A. thaliana promises to shed light on processes underlying the diversification of SRK and SCR genes. For example, expression in A. thaliana of SI specificities derived from different crucifer species will allow direct assays of the functional equivalence or nonequivalence of the corresponding S haplotypes, an issue that is difficult to resolve on the basis of sequence information alone.Although conceptually simple, expressing different SI specificities by transformation with different SRK/SCR gene pairs is not a straightforward proposition. Difficulties stem largely from the availability of appropriate cloned SRK/SCR variants for use in transformation experiments. A large number of SRK/SCR gene pairs are available from Brassica species as a result of extensive and long-standing studies of SI. However, attempts to restore SI in transgenic A. thaliana using Brassica S-locus genes had met with failure (Bi et al. 2000; J. B. Nasrallah, unpublished data), possibly because of the inability of Brassica SRKs to interact productively with A. thaliana components of the SI signal transduction pathway. In the past few years, studies of SI were initiated in self-incompatible species more closely related to A. thaliana, such as A. lyrata, A. halleri, and Capsella grandiflora. However, with a few exceptions, these studies produced only partial SRK and SCR sequences amplified from genomic DNA (Schierup et al. 2001; Prigoda et al. 2005; Bechsgaard et al. 2006; Paetsch et al. 2006). The challenging task of cloning the very highly polymorphic SCR sequences and complete SRK and SCR genes, which requires genomic library construction and in many cases chromosome walking, has only been accomplished for two S haplotypes of A. lyrata, Sb (hereafter AlSb, which was used in previous transformation studies (Nasrallah et al. 2002, 2004), and Sa (AlSa; Kusaba et al. 2001), and for the S7 haplotype of C. grandiflora (CgS7; Nasrallah et al. 2007).In this article, we report the isolation of two new SRK/SCR gene pairs from genomic libraries of A. lyrata and expression of the corresponding SI specificities in A. thaliana. We also describe a novel strategy for rapid and efficient transfer of several distinct SI specificities into A. thaliana, which only requires knowledge of the eSRK sequence and SCR second-exon sequences that encode the mature SCR protein.     

Effects of Inhibitors of Protein Serine/Threonine Phosphatases on Pollination in Brassica

We have examined the effect of the protein phosphatase inhibitors okadaic acid and microcystin on pollen-pistil interactions in Brassica. Inhibitor-treated flowers or floral buds were pollinated with untreated pollen and examined for pollen tube growth by fluorescence microscopy. Our results show that type 1 or type 2A serine/threonine phosphatases play a crucial role in the pollination responses of Brassica. We observed two distinct effects of protein phosphatase inhibitors on pollination: (a) the inhibition of pollen tube growth during cross-pollination in flowers, and (b) the break-down of self-incompatibility or promotion of pollen tube growth during self-pollination in flower buds just prior to anthesis. Thus, treatment of flower pistils with protein phosphatase inhibitors resulted in the inhibition of pollen tube growth at the surface of the papillar cells of the stigma in crosses between different self-incompatible Brassica oleracea strains, in an interspecific cross between B. oleracea and Brassica campestris, and in self-pollinations of a self-fertile Brassica napus cultivar. With four different self-incompatibility genotypes, treatment of mature flowers with protein phosphatase inhibitors had no effect on self-pollination response. In contrast, treatment of flower buds just prior to the anthesis stage allowed self-pollen tube invasion of papillar cells. However, the magnitude of this effect was genotype dependent, being most pronounced in the S22 genotype. The data support the conclusion that pollinations in Brassica are controlled in part by the presence of phosphorylated proteins in the papillar cells of the stigma, and that the quantity of these proteins or their levels of phosphorylation changes during stigma development.     

Structure and expression of AtS1, an Arabidopsis thaliana gene homologous to the S-locus related genes of Brassica

Summary Genetic and molecular analysis of the self-incompatibility locus (S-locus) of the crucifer Brassica has led to the characterization of a multigene family involved in pollen-stigma interactions. While the crucifer Arabidopsis thaliana does not have a self-incompatibility system, S-related sequences were detected in this species by cross-hybridization with Brassica DNA probes. In this paper, we show that an A. thaliana S-related sequence, designated AtS1, is expressed specifically in flower buds. Sequence analysis suggests that AtS1 encodes a secreted glycoprotein that is most similar to the Brassica S-locus related protein SLR1. As has been proposed for SLR1, this gene may be involved in determining some fundamental aspect of pollen-stigma interactions during pollination. The molecular and genetic advantages of the Arabidopsis system will provide many avenues for testing this hypothesis.     

Isolation of genes abundantly expressed in rice anthers at the microspore stage

A cDNA library of rice (Oryza sativa L.) has been constructed from anthers at an early stage of pollen development. By differential screening of the library, we have isolated cDNAs of two genes, designated as Osc4 and Osc6, that are abundantly expressed in anthers containing tetrads and uninucleate microspores, but are not expressed in leaves or roots. Expression of Osc4 is absent in mature anthers, while Osc6 is present although the expression decays during pollen maturation. A comparison of the nucleotide and deduced amino acid sequences with those in data banks has not shown significant homology to known molecules.