Trichinella spiralis infection decreases the diversity of the intestinal flora in the infected mouse

BackgroundTrichinella spiralis is a kind of intestinal nematode that can strongly modulate the host immune system. However, the effects of T. spiralis infection on the intestinal flora are poorly understood. This study aimed to explore the effect of T. spiralis infection on the intestinal flora.MethodsThe intestinal contents of T. spiralis infected mice were examined through high-throughput sequencing (Illumina) of the V3–V4 hypervariable region in bacterial 16S rRNA gene. The sequences were analyzed using the QIIME software package and other bioinformatics methods.ResultsAltogether 2,899,062 sequences were generated from the samples collected from different intestinal regions at various infection time points; the 44,843 Operational Taxonomic Unit (OTUs) analysis showed that T. spiralis infection would decrease the diversity of intestinal flora in the infected mice relative to that in the uninfected ones, especially in the large intestine and feces. Further analysis indicated that, the genera Oscillospira from the phylum Firmicutes showed a higher abundance in the helminth-infected small and larger intestines; the genera Bacteroides from the phyla Bacteroides, the genera Lactobacillus from the phyla Firmicutes, the genera Escherichia from the phyla Proteobacteria, and the genera Akkermansia from the phyla Verrucomicrobia displayed increased abundances in the T. spiralis positive fecal samples compared with those in the negative samples.ConclusionsT. spiralis infection decreases the diversity of the intestinal flora in the infected mouse. However, it remains unclear about the association between the changes in intestinal flora caused by T. spiralis infection and the parasite pathogenesis, which should be further examined.     

An evaluation of the pharmacologic inhibition of the immediate and late cutaneous reaction to allergen

The effects of an H₁ antagonist (chlorpheniramine) and an H₂ antagonist (cimetidine) alone or in combination, and of ASA on the ICR and the LCR to timothy or ragweed were evaluated. HCRs were also applied at each testing. The H₁ blocker alone significantly inhibited the HCR and the ICR, but not the LCR. The H₂ blocker by itself had no effect on HCR, ICR, or LCR. The addition of the H₂ to the H₁ blocker markedly increased the H₁ blocker's inhibition of the HCR and ICR and completely obliterated the LCR in most subjects. These findings, which could not be explained by simple additive effects, suggest a synergistic activity of the H₁ and the H₂ blocker combination. ASA had no effect on HCR, ICR, or LCR, casting doubt on the possible role of prostaglandins in the LCR.     

Comparative investigation of the role of the YadA, InvA, and PsaA genes in the pathogenicity of Yersinia pseudotuberculosis

The role of yadA, invA, and psaA genes in virulence was studied using a Yersinia pseudotuberculosis strain isolated from a patient with Far-East scarlatinoid fever as a model. Isogenic single, double, and multiple mutants of the studied genes were constructed, in which wild-type alleles were inactivated by the insertion of various antibiotic-resistance genes. LD₅₀ and body weight dynamics of infected laboratory animals were used as virulence indicators. It has been established that the yadA gene is the primary determinant of bacterial virulence. This gene also causes the loss of body weight in laboratory animals infected by sublethal doses of Y. pseudotuberculosis. The invA gene, rather than yadA or psaA, plays a major role in the penetration of pathogenic microorganisms into eukaryotic cells. The effects of the yadA and invA genes on bacterial virulence and invasion, respectively, do not depend on the expression of other studied genes.     

Molecular identification of the parasites causing cutaneous leishmaniasis on the Caribbean coast of Colombia

All clinical manifestations of leishmaniasis exist in Colombia, the cutaneous form being the most frequent in the department of Sucre, where the Leishmania species associated with cutaneous leishmaniasis (CL) is unknown. This study was carried out to determine which Leishmania species was responsible for CL in Sucre, based on amplification and sequencing of the Cyt b gene. Isolates of Leishmania were obtained after CL diagnosis of eight patients who received attention in several health care centers of the study area. The nucleotide sequences obtained from patients were compared to Leishmania reference strains and six of the isolates identified as Leishmania (Viannia) braziliensis, the remaining two being identified as Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis. This represents the first report of the presence of L. (V.) guyanensis on the Caribbean coast of Colombia.     

Polymorphisms of the lamina maturation pathway and their association with the metabolic syndrome: the DESIR prospective study

Laminopathies are rare monogenic diseases, some of them exhibiting features of the metabolic syndrome. These diseases are mainly due to mutations in LMNA, encoding A-type lamins. One LMNA polymorphism, rs4641, has been associated with the metabolic syndrome, but results have been controversial. We therefore investigated the effect of single nucleotide polymorphisms (SNPs) in the LMNA gene in combination with four other genes encoding enzymes influencing lamin post-translational maturation on risk of metabolic syndrome (MS). Twenty-three tagging SNPs characterising the haplotypic variability of five genes (LMNA, ICMT, ZMPSTE24, FNTA and FNTB) were genotyped in 3,916 French men and women who took part in the prospective DESIR study. Single locus and haplotype analyses were performed but did not detect any significant association with the risk of MS. No robust interaction between SNPs located in different genes on the risk of MS was identified. In conclusion, we did not observe any convincing evidence that common polymorphisms of the lamina pathway could modulate the risk of MS.     

Gold nanoprobe assay for the identification of mycobacteria of the Mycobacterium tuberculosis complex

Members of the Mycobacterium tuberculosis complex (MTC) are causative agents of human and animal tuberculosis. This complex encompasses several phylogenetically related species, including M. tuberculosis, the main aetiological agent of human tuberculosis, and Mycobacterium bovis, the causative agent of bovine tuberculosis, a relevant worldwide zoonosis. Clear epidemiological evaluation of appropriate and effective treatment requires unambiguous differentiation between MTC members. Routine diagnosis has been increasingly relying on the molecular identification of MTC members. In the present study, we report the use of a gold nanoparticle-based approach for the sensitive, specific and fast identification of MTC and for the differentiation of M. bovis and M. tuberculosis using the gyrB locus as target. This gold nanoprobe strategy relies on the colorimetric differentiation of specific DNA sequences based on differential aggregation profiles in the presence or absence of specific target hybridization. Three nanoprobes were designed and successfully used for the specific identification of members of MTC, M. bovis and M. tuberculosis.     

Protein binding sites involved in the assembly of the KplE1 prophage intasome

The organization of the recombination regions of the KplE1 prophage in Escherichia coli K12 differs from that observed in the λ prophage. Indeed, the binding sites characterized for the IntS integrase, the TorI recombination directionality factor (RDF) and the integration host factor (IHF) vary in number, spacing and orientation on the attL and attR regions. In this paper, we performed site-directed mutagenesis of the recombination sites to decipher if all sites are essential for the site-specific recombination reaction and how the KplE1 intasome is assembled. We also show that TorI and IntS form oligomers that are stabilized in the presence of their target DNA. Moreover, we found that IHF is the only nucleoid associated protein (NAP) involved in KplE1 recombination, although it is dispensable. This is consistent with the presence of only one functional IHF site on attR and none on attL.     

Establishment of the bacterial fecal community during the first month of life in Brazilian newborns

OBJECTIVE:

The establishment of the intestinal microbiota in newborns is a critical period with possible long-term consequences for human health. In this research, the development of the fecal microbiota of a group of exclusively breastfed neonates living in low socio-economic conditions in the city of São Paulo, Brazil, during the first month of life, was studied.

METHODS:

Fecal samples were collected from ten neonates on the second, seventh, and 30^th days after birth. One of the neonates underwent antibiotic therapy. Molecular techniques were used for analysis; DNA was extracted from the samples, and 16S rRNA libraries were sequenced and phylogenetically analyzed after construction. A real-time polymerase chain reaction (PCR) was performed on the samples taken from the 30^th day to amplify DNA from Bifidobacterium sp.

RESULTS:

The primary phylogenetic groups identified in the samples were Escherichia and Clostridium. Staphylococcus was identified at a low rate. Bifidobacterium sp. was detected in all of the samples collected on the 30^th day. In the child who received antibiotics, a reduction in anaerobes and Escherichia, which was associated with an overgrowth of Klebsiella, was observed throughout the experimental period.

CONCLUSION:

The observed pattern of Escherichia predominance and reduced Staphylococcus colonization is in contrast with the patterns observed in neonates living in developed countries.     

Identification of Streptococci to Species Level by Sequencing the Gene Encoding the Manganese-Dependent Superoxide Dismutase

We have used a PCR assay based on the use of degenerate primers in order to characterize an internal fragment (sodA_int) representing approximately 85% of the genes encoding the manganese-dependent superoxide dismutase in various streptococcal type strains (S. acidominimus, S. agalactiae, S. alactolyticus, S. anginosus, S. bovis, S. constellatus, S. canis, S. cricetus, S. downei, S. dysgalactiae, S. equi subsp. equi, S. equi subsp. zooepidemicus, S. equinus, S. gordonii, S. iniae, S. intermedius, S. mitis, S. mutans, S. oralis, S. parasanguis, S. pneumoniae, S. porcinus, S. pyogenes, S. salivarius, S. sanguis, S. sobrinus, S. suis, S. thermophilus, and S. vestibularis). Phylogenetic analysis of these sodA_int fragments yields an evolutionary tree having a topology similar to that of the tree constructed with the 16S rRNA sequences. We have shown that clinical isolates could be identified by determining the positions of their sodA_int fragments on the phylogenetic tree of the sodA_int fragments of the type species. We propose this method for the characterization of strains that cannot be assigned to a species on the basis of their conventional phenotypic reactions.     

Imd pathway is involved in the interaction of Drosophila melanogaster with the entomopathogenic bacteria,Xenorhabdus nematophila and Photorhabdus luminescens

Xenorhabdus nematophila/Steinernema carpocapsae and Photorhabdus luminescens/Heterorhabditis bacteriophora are nemato-bacterial complexes highly pathogenic for insects. Using a syringe as artificial vector, we have analyzed the effects of the two bacteria, X. nematophila and P. luminescens on the genetic tool insect, Drosophila melanogaster. Both bacteria were found to kill adult flies in a dose dependent manner with X. nematophila being the fastest. On the other hand, when an injection of non-pathogenic bacteria, Escherichia coli, is performed 1 day before challenge with the entomopathogenic bacteria, then the survival of Drosophila flies was prolonged by at least 20 h. After injection of entomopathogenic bacteria, Drosophila mutant Dif¹, affected on the Toll pathway, showed a similar phenotype than wild-type flies whereas Drosophila mutant Dredd^D55, affected on the imd pathway, was not protected by a prior injection of E. coli. This suggested that members of the imd pathway might be targets of these entomopathogenic bacteria albeit synthesis of antimicrobial peptides through this signaling pathway was induced by X. nematophila as well as P. luminescens. Finally, P. luminescens phoP mutant, an avirulent mutant in the Lepidopteran insect, Spodoptera littoralis, was found poorly virulent for D. melanogaster. phoP mutant partially protected D. melanogaster flies if injected 1 day before the injection of P. luminescens wild-type TT01 to the same extent than the E. coli-induced protection. However, phoP recovered a level of pathogenicity comparable to P. luminescens wild-type TT01 when injected to Drosophila flies affected on the imd pathway.     

Agrobacterium fabrum gene atu1420 regulates the pathogenicity by affecting the degradation of growth- and virulence-associated phenols

Agrobacterium fabrum is a phytopathogen that causes the crown gall disease. Some plant-derived molecules, e.g. phenols, directly affect A. fabrum-plant interactions. Here, we characterize a phenolic catabolism-related gene, atu1420, that affects the pathogenicity of A. fabrum. Atu1420 is predicted to be an O-demethylase with high structural homology to Sphingomonas paucimobilis LigM. The HPLC-UV analysis showed that atu1420 affected the degradation of acetosyringone (AS). The deletion of atu1420 gene significantly enhanced the AS-induced virulence (vir) gene expression. atu1420 was shown to relieve the inhibitory effect of vanillic acid on the AS-induced vir gene expression and the growth of A. fabrum. The expression of atu1420 and the degradation of AS in A. fabrum C58 was up-regulated by the addition of indole acetic acid (IAA). The inhibitory effect of IAA on the AS-induced vir gene expression was partially relieved by the deletion of atu1420 gene, indicating that accelerating the degradation of AS is one of the ways that IAA inhibits vir genes induction. Furthermore, atu1420 mutant produced more pronounced tumors on kalanchoe leaves than the wild-type strain. These findings reveal the role of atu1420 in A. fabrum-host interactions and will broaden our understanding of the regulatory network of the interactions.     

Immunity to bacterial infection in the chicken

Bacterial infections remain important to the poultry industry both in terms of animal and public health, the latter due to the importance of poultry as a source of foodborne bacterial zoonoses such as Salmonella and Campylobacter. As such, much focus of research to the immune response to bacterial infection has been to Salmonella. In this review we will focus on how research on avian salmonellosis has developed our understanding of immunity to bacteria in the chicken from understanding the role of TLRs in recognition of bacterial pathogens, through the role of heterophils, macrophages and γδ lymphocytes in innate immunity and activation of adaptive responses to the role of cellular and humoral immunity in immune clearance and protection. What is known of the immune response to other bacterial infections and in particular infections that have emerged recently as major problems in poultry production including Campylobacter jejuni, Avian Pathogenic Escherichia coli, Ornithobacterium rhinotracheale and Clostridium perfringens are discussed.     

Exploring the dynamics of P300 amplitude in patients with schizophrenia

This study investigated the time-frequency dynamics of P300 generation in patients with first-onset schizophrenia.A group of 40 patients with first-onset schizophrenia and 40 controls performed an auditory oddball task. Wavelet analysis of the single-trial data was used to compute the Event-Related Spectral Perturbation (ERSP) and the Inter-Trial Phase Coherence (ITC) for the delta, theta, alpha, beta and gamma bands on the 50 ms window around peak P300 amplitude. The contribution of power and synchrony for P300 amplitudes was studied through correlation and regression analysis. Further, two sub-samples in which patients had lower or higher P300 amplitudes than their control match were contrasted.P300 amplitude did not differ between patients and controls. The frequency domain analysis revealed that controls display larger reductions on gamma power than patients. However, this gamma activity might be the result of micro-saccadic muscular artifacts.Regression analysis shows that P300 amplitude is highly dependent on delta power and synchronization. The analysis of the subsamples confirmed that while gamma power differences are dependent on the diagnosis, delta and theta synchronization are related to P300 amplitude, irrespective of diagnosis.     

Contribution of the twin arginine translocation system to the virulence of enterohemorrhagic Escherichia coli O157:H7

Shiga toxin-producing Escherichia coli O157:H7 is a major food-borne infectious pathogen. In order to analyze the contribution of the twin arginine translocation (TAT) system to the virulence of E. coli O157:H7, we deleted the tatABC genes of the O157:H7 EDL933 reference strain. The mutant displayed attenuated toxicity on Vero cells and completely lost motility on soft agar plates. Further analyses revealed that the ΔtatABC mutation impaired the secretion of the Shiga toxin 1 (Stx1) and abolished the synthesis of H7 flagellin, which are two major known virulence factors of enterohemorrhagic E. coli O157:H7. Expression of the EDL933 stxAB₁ genes in E. coli K-12 conferred verotoxicity on this nonpathogenic strain. Remarkably, cytotoxicity assay and immunoblot analysis showed, for the first time, an accumulation of the holotoxin complex in the periplasm of the wild-type strain and that a much smaller amount of StxA₁ and reduced verotoxicity were detected in the ΔtatC mutant cells. Together, these results establish that the TAT system of E. coli O157:H7 is an important virulence determinant of this enterohemorrhagic pathogen.     

Effects of Anguillicola novaezelandiae on the levels of cortisol and hsp70 in the European eel

The nematodes Anguillicola novaezelandiae and Anguillicola crassus are both alien parasites of the European eel with severe adverse effects on their new host. Both species differ in terms of their invasiveness and their severity of harmful effects on the European eel. The purpose of this study was to determine under laboratory conditions whether stages of A. novaezelandiae induce stress in European eels (Anguilla anguilla) and if these levels differ from stress levels induced by A. crassus. We analysed levels of plasma cortisol and hepatic hsp70 of eels experimentally infected with A. novaezelandiae and compared them to uninfected eels as well as to eels experimentally infected with A. crassus. Larval stages of A. novaezelandiae induced higher levels of plasma cortisol compared to uninfected controls, while adult parasites increased the levels of hepatic hsp70 above those of uninfected controls. The eels’ cortisol response is induced by larval stages of A. novaezelandiae, while adult stages elevate levels of hepatic hsp70. Levels of stress induced by A. novaezelandiae are comparable to those induced by A. crassus.