Circulating levels of miR-150 are associated with poorer outcomes of A/H1N1 infection.

BACKGROUND: Overproduction of pro-inflammatory cytokines and chemokines is frequently associated with severe clinical manifestations in patients infected with influenza A/H1N1 virus. Micro-RNAs (miRNAs) are highly conserved small non-coding RNA molecules that post-transcriptionally regulate gene expression and are potential biomarkers and therapeutic targets in different inflammatory conditions. METHODS: We studied the circulating and miRNA profiles in critically ill A/H1N1 patients, A/H1N1 patients with milder disease, asymptomatic housemates and healthy controls. Cytokine, chemokine and growth factors that were potential targets of differentially expressed miRNAs were assessed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and interactome analysis of these miRNAs were also performed. RESULTS: Critically ill patients exhibited a significant over-expression of circulating miR-150 (p<0.005) when compared to patients with milder disease. miR-29c, miR-145 and miR-22 were differentially expressed in patients with severe A/H1N1 disease whereas miR-210, miR-126 and miR-222 were downregulated in individuals exposed to the A/H1N1 virus. Significant correlations (p<0.05) between circulating levels of miR-150 with IL-1ra, IL-2, IL-6, CXCL8, IFN-γ, CXCL10 and G-CSF were detected, particularly in critically ill patients. CONCLUSION: The up-regulation of miR-150 is associated with poorer outcomes of A/H1N1 infection. The differential expression of miRNAs related with immune processes in severe A/H1N1 disease supports the potential role of these miRNAs as biomarkers of disease progression.

[Respiratory infections and bacteremia caused by Neisseria meningitidis serogroup W]. / Infecciones respiratorias bacteriémicas por Neisseria meningitidis serogrupo W.

N. meningitidis serogroup W has recently been introduced into Chile. This serogroup has been associated with hypervirulent strains capable of causing outbreaks. Furthermore, there is data suggesting that the spectrum of clinical manifestations varies among different serogroups. Here we describe three cases of community acquired respiratory infections caused by N. meningitidis W, which were diagnosed by blood culture during 2013 in our hospital.

The shift from low to high non-structural protein 1 expression in rotavirus-infected MA-104 cells.

A hallmark of group/species A rotavirus (RVA) replication in MA-104 cells is the logarithmic increase in viral mRNAs that occurs four-12 h post-infection. Viral protein synthesis typically lags closely behind mRNA synthesis but continues after mRNA levels plateau. However, RVA non-structural protein 1 (NSP1) is present at very low levels throughout viral replication despite showing robust protein synthesis. NSP1 has the contrasting properties of being susceptible to proteasomal degradation, but being stabilised against proteasomal degradation by viral proteins and/or viral mRNAs. We aimed to determine the kinetics of the accumulation and intracellular distribution of NSP1 in MA-104 cells infected with rhesus rotavirus (RRV). NSP1 preferentially localises to the perinuclear region of the cytoplasm of infected cells, forming abundant granules that are heterogeneous in size. Late in infection, large NSP1 granules predominate, coincident with a shift from low to high NSP1 expression levels. Our results indicate that rotavirus NSP1 is a late viral protein in MA-104 cells infected with RRV, presumably as a result of altered protein turnover.

Extended culture up to the blastocyst stage: a strategy to avoid multiple pregnancies in assisted reproductive technologies.

The aim of this study was to review the experience and outcomes of assisted reproduction cycles with embryos grown up to day 5 of development, comparing different parameters according to the ages of the patients. We retrospectively studied 1,874 assisted reproduction cycles where embryo culture was extended up to the fifth or sixth day of development. All IVF and ICSI cycles were included, comparing, according to patient age, the following rates: blastocyst formation, pregnancy, implantation and abortion. As control, we analyzed cycles with donated oocytes from young donors (OD). The number of embryos reaching the blastocyst stage is similar in all groups of patients. Only the OD group was different in terms of blastocyst formation, pregnancy and implantation rates. Patients over 39 years of age had an abortion rate of 59.1 %, which is significantly higher than the other groups. Extended embryo culture up to the blastocyst stage can be implemented in programs of assisted reproduction in order to increase the pregnancy rate. The potential of blastocyst implantation is high, allowing us to transfer fewer embryos and reduce the probability of multiple pregnancies.

Mutations in the VP2 gene of rotavirus associated with benzimidazole sensitivity.

Rotavirus species A (RVA) is the etiological agent of acute gastroenteritis in young individuals of various animal species, including humans. Vaccination has helped to reduce the impact of these viruses on humans and some species of domestic mammals, but they do not confer complete immunity, so antirotavirus agents are another important control option. In this study, millimolar concentrations of benzimidazole inhibited the replication of the Rhesus rotavirus (RRV) strain of RVA. Two mutants partially resistant to the inhibitory effect of benzimidazole were independently selected, and their genomes and those of their parental strains were fully sequenced. Most (7/11) mutations occurred in the gene that encodes the VP2 protein, and similarly most of the missense mutations (5/9), including the only one shared by the two mutants (G2,414 → R[G/A], D800 N), occurred in the VP2 gene. Our results identify the VP2 gene as the primary target affected by benzimidazole.

Hepatitis B and C virus infection among HIV patients within the public and private healthcare systems in Chile: A cross-sectional serosurvey.

BACKGROUND: Coinfections of HIV patients with hepatitis B virus (HBV) and hepatitis C virus (HCV) are mayor public health problems, contributing to the emerging burden of HIV-associated hepatic mortality. Coinfection rates vary geographically, depending on various factors such as predominant transmission modes, HBV vaccination rates, and prevalence of HBV and HCV in the general population. In South America, the epidemiology of coinfections is uncertain, since systematic studies are scarce. Our study aimed to analyze rates of HBV and HCV infection in people living with HIV attending centers of the public and private health system in Chile. METHODS: We performed a cross-sectional study including a public university hospital and a private health center in Santiago, Metropolitan Region in Chile. Serum samples were used to determine serological markers of hepatitis B (HBsAg, anti-HBs, anti-HBc total, HBeAg, anti-HBe) and anti-HCV. Demographic, clinical and laboratory data were obtained from medical records. RESULTS: 399 patients were included (353 from public, 46 from private health center). Most (92.8%) were male, with a median age of 38.3 years; 99.4% acquired HIV through sexual contact (75.0% MSM); 25.7% had AIDS and 90.4% were on ART. In 78.9%, viral loads were <40 cps/mL; the median CD4 cell count was 468 cells/mm3. According to their serological status, 37.6% of patients were HBV naïve (susceptible), 6.5% were vaccinated, 43.6% had resolved HBV infection, and 5.8% were chronically infected. The rate of vaccination was 4.5% in the public and 21.7% in the private system. HCV coinfection was found in 1.0% of all patients. CONCLUSION: HBV coinfection rate was within the range of other South American countries, but lower than in non-industrialized regions in Asia and Africa. A low percentage of patients were HBV vaccinated, especially within the public system. HCV coinfection rate was very low, most probably due to the rareness of injecting drug use.

Periodontal condition is associated with adverse perinatal outcomes and premature rupture of membranes in low-income pregnant women in Bogota, Colombia: a case-control study.

Objectives: To assess the periodontal condition as a factor associated with adverse perinatal outcomes, premature rupture of membranes (PRM), and preeclampsia in low-income pregnant women treated at public hospitals in Bogotá, Colombia.Methods: Pregnant women with preterm birth (PTB) and low birth weight (LBW) or both conditions (n = 107/428), or only PTB (n = 73/292) or LBW (n = 74/296) or with PRM (n = 98/392) or preeclampsia (n = 76/304) in a ratio of four controls for each case, coming from three hospitals of the public Northern Network of Bogotá, Colombia were studied. Sociodemographic, perinatal adverse outcome history, antenatal care, chronic infections, periodontal condition, threatened abortion, bleeding in the second half of pregnancy, oligohydramnios, diabetes, gestational diabetes, alcohol consumption, hypertension, smoking, alcohol during pregnancy were determined. Logistic regression was conducted to establish factors associated to perinatal adverse outcomes. Multiple correspondence analysis was conducted as secondary analysis.Results: Threatened abortion, absence of antenatal care, hypertension, chronic infections, and periodontal condition were the most important factors associated with perinatal adverse outcomes. The presence of periodontal pockets was associated with LBW OR 2.52 (IC95% 1.36-4.70), PTB OR 2.04 (IC95% 1.10-3.64), PTB-LBW or both OR 2.08 (IC95% 1.18-3.31), PRM OR 2.04 (IC95% 1.17-3.56). Periodontal pockets presence was not associated with preeclampsia. Multiple correspondence analyses showed high correlation between PRM with chronic infection and presence of periodontal pockets.Conclusions: Periodontal condition is a factor independent of other important risk factors for a perinatal adverse outcome and PRM. Prevention of periodontal disease should be included in preconception and prenatal care programs.

Identification of amino acid variants in the hepatitis C virus non-structural protein 4A.

Chronic infections by hepatitis C virus (HCV) are a major cause of cirrhosis and hepatic cancer. The replication of HCV involves translation and proteolytic processing of polyproteins. The HCV single-stranded RNA encodes a single polyprotein of C/E1/E2/p7/NS2/NS3/NS4A/NS4B/NS5A/NS5B. The structural proteins, C, E1, E2, and p7, arise from the viral polyprotein by host proteases. Cleavage at the non-structural NS2/NS3 junction is performed by the NS2 protease. NS3 forms a complex with NS4A to cleave the rest of the viral polyprotein. The central 12-amino-acid sequence of NS4A, 21-GSVVIVGRIILS-32 (NS4Awt) is a determinant to enhance the NS3 protease activity at the NS5A/5B junction. We found that, from 13 blood donors infected with HCV, one sample showed five amino acid changes in the NS4A central region at V23I, I25C, I30S, L31T, and S32L, and another sample showed three changes at V23I, I25C, and I30V in this region. The other 11 samples showed the NS4Awt sequence. The effect of such amino acid variations on the NS3 proteolytic activity was evaluated in vitro using the central 12-amino-acid NS4Awt sequence with specific changes joined to NS3, and NS5A/5B as a substrate. Our results indicate that the amino acid changes of NS4A at V23I and I25C do not enhance the protease activity of NS3, whereas the amino acid changes at I30S, L31T, and S32L, as well as the NS4Awt sequence, enhance NS3 activity. Our results confirm that protease cofactor, encoded in NS4A, is of major regulatory relevance for the replication cycles of HCV.

Rotavirus infections in Galapagos sea lions.

Group A rotaviruses infect and cause diarrhea in the young of a broad range of terrestrial mammals, but it is unknown, to our knowledge, whether they infect marine mammals. During February and March of 2002 and 2003, we collected 125 serum samples and 18 rectal swab samples from Galapagos sea lion pups (GSL, Zalophus wollebaeki), and 22 serum samples from Galapagos fur seal pups (GFS, Arctocephalus galapagoensis) from nine islands of the Galapagos archipelago, Ecuador. Sera were tested for antibodies (immunoglobulin G [IgG]) to rotavirus by an enzyme immunoassay using rhesus rotavirus as the capture antigen. In addition, rectal swabs were analyzed for the presence of rotavirus genomic double-stranded RNA by silver-stained polyacrylamide gel electrophoresis. Antibodies to rotavirus were detected in 27 GSL pups (22%) and five GFS pups (23%), and rotavirus RNA was detected in the fecal sample from one GSL pup (6%). These results provide the first evidence that rotavirus infections are prevalent at an early age in Galapagos sea lions and Galapagos fur seals.

Impact of antibiotic prophylaxis on the incidence, nature, magnitude, and duration of bacteremia associated with dental procedures: A systematic review.

BACKGROUND: Antibiotic prophylaxis (AP) is used routinely in high-risk groups of patients to reduce bacteremia and the risk of developing infective endocarditis (IE). In this systematic review, the authors evaluated the efficacy of AP on the incidence, nature, magnitude, and duration of post-dental procedure bacteremia. METHODS: The authors conducted a systematic search of the literature using MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials up to and including May 2019. They included randomized clinical trials in which researchers compared antibiotics with a placebo or no treatment (as the control). They undertook random-effects meta-analyses to evaluate the incidence of bacteremia after dental procedures. RESULTS: The authors included 12 studies in the review. The studies evaluated the incidence of bacteremia after AP with American Heart Association (AHA) protocol antibiotics (amoxicillin, clindamycin, cephalosporin, and azithromycin) or non-AHA protocol antibiotics (moxifloxacin and intravenous [IV] amoxicillin-clavulanic acid). The pooled analysis revealed that antibiotics significantly reduced the bacteremia incidence, but their effectiveness was moderate (risk ratio, 0.50; 95% confidence interval, 0.38 to 0.67). IV amoxicillin-clavulanic acid promoted a considerable reduction in bacteremia. However, in patients with penicillin allergies, antibiotics (that is, clindamycin and cephalosporin) had lower efficacy. PRACTICAL IMPLICATIONS: Oral amoxicillin is still the antibiotic of choice to reduce bacteremia. IV amoxicillin-clavulanic acid could be used for patients at high risk of developing IE who require invasive dental procedures, have high levels of dental infection, and are to be treated under general anesthesia. In patients with penicillin allergies, oral azithromycin showed a higher efficacy for the reduction of bacteremia and the use of clindamycin should be reviewed. Antibiotic premedication should be limited to patients at high risk of developing IE, according to the indications of the AHA guide.

[Evaluation of the characteristics of aortic dissection by computed angio-tomography in the Mexican population]. / Evaluación de las características de la disección aórtica en la población mexicana mediante angiotomografía computarizada.

OBJECTIVE: To review aortic dissection (AD) in the Mexican population. METHOD: A retrospective study was conducted using 434 medical records of patients with aortic angio-tomography between November 2014 and October 2015. A sample was obtained of 32 patients with a first time diagnosis of AD. An analysis was performed of the dissections according to gender, age group, Stanford/De Bakey classification, and mortality rate 6 months after diagnosis. Statistical analysis was performed by obtaining the Chi squared index for the independent variables of gender, Marfan syndrome, systemic arterial hypertension, as well as calcified atheromatous disease in association with dissection subtypes, re-entry sites, and hypo-perfusion signs. RESULTS: The patients included 65.6% males with a mean age of 54.5 years, and 34.4% females with mean age of 42.5 years. The most common dissection subtype was B/3. Mortality rate at 6 months was 18.7%. There was a significant association, with a marginal P in patients with Marfan syndrome and Stanford subtypes of AD (P=.0506). There was a significant association in patients with abdominal aortic aneurysm, when compared with Stanford subtypes of AD (P=.047104). CONCLUSIONS: AD is an emergency in which diagnosis and timely management are essential to improve prognosis. In the sample presented here, a significant association was found in patients with a history of Marfan syndrome and abdominal aneurysms with dissections according to the Stanford classification. The rest of the independent variables did not show any significant association, probably related to the size of the sample.

Species A rotavirus NSP3 acquires its translation inhibitory function prior to stable dimer formation.

Species A rotavirus non-structural protein 3 (NSP3) is a translational regulator that inhibits or, under some conditions, enhances host cell translation. NSP3 binds to the translation initiation factor eIF4G1 and evicts poly-(A) binding protein (PABP) from eIF4G1, thus inhibiting translation of polyadenylated mRNAs, presumably by disrupting the effect of PABP bound to their 3'-ends. NSP3 has a long coiled-coil region involved in dimerization that includes a chaperone Hsp90-binding domain (HS90BD). We aimed to study the role in NSP3 dimerization of a segment of the coiled-coil region adjoining the HS90BD. We used a vaccinia virus system to express NSP3 with point mutations in conserved amino acids in the coiled-coil region and determined the effects of these mutations on translation by metabolic labeling of proteins as well as on accumulation of stable NSP3 dimers by non-dissociating Western blot, a method that separates stable NSP3 dimers from the monomer/dimerization intermediate forms of the protein. Four of five mutations reduced the total yield of NSP3 and the formation of stable dimers (W170A, K171E, R173E and R187E:K191E), whereas one mutation had the opposite effects (Y192A). Treatment with the proteasome inhibitor MG132 revealed that stable NSP3 dimers and monomers/dimerization intermediates are susceptible to proteasome degradation. Surprisingly, mutants severely impaired in the formation of stable dimers were still able to inhibit host cell translation, suggesting that NSP3 dimerization intermediates are functional. Our results demonstrate that rotavirus NSP3 acquires its function prior to stable dimer formation and remain as a proteasome target throughout dimerization.

Enveloped and non-enveloped viral-like particles in Trypanosoma cruzi epimastigotes.

Electron microscopy is routinely used to identify viral infections in protozoan parasites. These viruses have been described as non-enveloped and icosahedral structures with a diameter of 30-60 nm. Most of them are classified within the non-segmented dsRNA Totiviridae family. We observed virus-like particles (VLPs) through transmission electron microscopy in the cytoplasm of Trypanosoma cruzi epimastigotes grown in cultures. Clusters of electrodense enveloped VLPs having a diameter of 48 nm were also observed. These clusters appear to have been released from distended Golgi cisternae. Furthermore, a paracrystalline array of electrodense, non-enveloped VLPs (with a diameter of 32 nm) were found in distended Golgi cisternae or as smaller clusters at a distance from the RE or Golgi. We cannot rule out that the 48 nm enveloped VLPs belong to the ssRNA Flaviviridae family because they are within its size range. The localization of enveloped VLPs is consistent with the replication strategy of these viruses that transit through the Golgi to be released at the cell surface. Due to the size and shape of the 32 nm non-enveloped VLPs, we propose that they belong to the dsRNA Totiviridae family. This is the first description of cytoplasmic enveloped and non-enveloped VLPs in T. cruzi epimastigotes.

Analysis of human rotavirus G1P[8] strains by RFLP reveals higher genetic drift in the VP7 than the VP4 gene during a 4-year period in Mexico.

Several studies have demonstrated that rotaviruses of the G1P[8] genotype are among the most important worldwide. Sequence analysis of G1P[8] strains has revealed high genetic variability of VP4 and VP7 genes. The aim of this study was to investigate by restriction fragment length polymorphism (RFLP) analysis the genetic variability of the VP7 and VP4 genes within rotaviruses of the G1P[8] genotype. A total of 60 rotavirus-positive fecal samples genotyped as G1P[8], were collected from children with acute diarrhea under 5 years of age, between October 1995 and October 1998. The VP7 and VP4 genes were amplified by RT/PCR, using the Beg9/End9 primer pair and the Con3 and Con2 primers, respectively. VP7 amplicons were digested with three restriction enzymes Hae III, Taq I and Rsa I in separate reactions and VP4 amplicons were digested similarly with endonucleases Hinf I, Sau96 I and Rsa I. Analysis of the digested VP7 and VP4 amplicons showed a higher genetic drift for the VP7 gene (18 RFLPs) compared to the VP4 gene (9 RFLPs). The combination of profiles for both VP7 and VP4 amplicons, showed 27 different patterns, none of them similar to the Wa-1 strain. Furthermore, RFLP analysis of these G1P[8] strains, clearly differentiated the viruses into two main clusters, both of them sharing the same restriction pattern for the VP4 gene, and a different one for the VP7 gene.

Amazon River dissolved load: temporal dynamics and annual budget from the Andes to the ocean.

The aim of the present study is to estimate the export fluxes of major dissolved species at the scale of the Amazon basin, to identify the main parameters controlling their spatial distribution and to identify the role of discharge variability in the variability of the total dissolved solid (TDS) flux through the hydrological cycle. Data are compiled from the monthly hydrochemistry and daily discharge database of the "Programa Climatologico y Hidrologico de la Cuenca Amazonica de Bolivia" (PHICAB) and the HYBAM observatories from 34 stations distributed over the Amazon basin (for the 1983-1992 and 2000-2012 periods, respectively). This paper consists of a first global observation of the fluxes and temporal dynamics of each geomorphological domain of the Amazon basin. Based on mean interannual monthly flux calculations, we estimated that the Amazon basin delivered approximately 272 × 10(6) t year(-1) (263-278) of TDS during the 2003-2012 period, which represents approximately 7 % of the continental inputs to the oceans. This flux is mainly made up by HCO3, Ca and SiO2, reflecting the preferential contributions of carbonate and silicate chemical weathering to the Amazon River Basin. The main tributaries contributing to the TDS flux are the Marañon and Ucayali Rivers (approximately 50 % of the TDS production over 14 % of the Amazon basin area) due to the weathering of carbonates and evaporites drained by their Andean tributaries. An Andes-sedimentary area-shield TDS flux (and specific flux) gradient is observed throughout the basin and is first explained by the TDS concentration contrast between these domains, rather than variability in runoff. This observation highlights that, under tropical context, the weathering flux repartition is primarily controlled by the geomorphological/geological setting and confirms that sedimentary areas are currently active in terms of the production of dissolved load. The log relationships of concentration vs discharge have been characterized over all the studied stations and for all elements. The analysis of the slope of the relationship within the selected contexts reveals that the variability in TDS flux is mainly controlled by the discharge variability throughout the hydrological year. At the outlet of the basin, a clockwise hysteresis is observed for TDS concentration and is mainly controlled by Ca and HCO3 hysteresis, highlighting the need for a sampling strategy with a monthly frequency to accurately determine the TDS fluxes of the basin. The evaporite dissolution flux tends to be constant, whereas dissolved load fluxes released from other sources (silicate weathering, carbonate weathering, biological and/or atmospheric inputs) are mainly driven by variability in discharge. These results suggest that past and further climate variability had or will have a direct impact on the variability of dissolved fluxes in the Amazon. Further studies need to be performed to better understand the processes controlling the dynamics of weathering fluxes and their applicability to present-day concentration-discharge relationships at longer timescales.

Ability of Bifidobacterium strains with acquired resistance to bile to adhere to human intestinal mucus.

The hydrophobicity and capacity to adhere to human intestinal mucus of Bifidobacterium strains with acquired resistance to bile were assessed and compared with those of their more sensitive original strains. The resistant variants used were previously obtained [Int. J. Food Microbiol. 82 (2003) 191; Int. J. Food Microbiol. 94 (2004) 79] by progressive adaptation of originally more sensitive strains to gradually increasing concentrations of bile. In five out of the seven groups of original and bile-resistant variants tested the resistant strains showed higher adhesion levels to human mucus (range between 1.4- and 4-fold) than their corresponding original strains. However, in the presence of physiologic concentrations of bile (0.3%, w/v) the adhesion level of all Bifidobacterium strains dropped between 7% and 74%, depending on the strain. In spite of this, the adhesion capability of three bile-resistant variants remained higher than that of their originals. Hydrophobicity evidenced considerable variability; in four out of the seven bile-resistant strains it was higher than in the original strains, although no direct correlation between adhesion and hydrophobicity could be established. It was concluded that the acquisition of bile resistance by our Bifidobacterium strains promoted changes in hydrophobicity and in the adhesion of these microorganisms to human intestinal mucus.

Acquisition of bile salt resistance promotes antibiotic susceptibility changes in bifidobacterium.

The effect of acquired resistance to bile on the antimicrobial sensitivity of two Bifidobacterium strains (Bifidobacterium animalis IPLA4549 and Bifidobacterium longum NIZO B667) was studied. The MICs of 23 different antibiotics belonging to the most clinically important groups were determined by using the Etest method, which comprises nonporous plastic strips calibrated with a predefined gradient of antibiotic concentrations covering 15 twofold dilutions. The strains were sensitive to most antibiotics assayed, although they tolerated relatively high concentrations of gentamicin, kanamycin, streptomycin, polymyxin B, and ciprofloxacin (from 32 to more than 1,024 microg/ml). One of the bile-adapted strains was more strongly resistant to ceftazidime than was its parent bile-sensitive strain, and the other bile-adapted strain had increased resistance to tetracyclines. Therefore, to test the possibility that the acquisition of stable resistance to bile could be associated with a general increase in resistance to some antibiotics, we analyzed the sensitivities of four additional pairs of parent strains and their bile-adapted derivatives to ceftazidime and three tetracyclines (doxycycline, minocycline, and tetracycline). Three of the bile-resistant derivatives had increased resistance to ceftazidime (more than 256-fold) compared with their parents, and two had enhanced resistance to tetracyclines (at least 12-fold). Thus, the acquisition of bile salts resistance in Bifidobacterium induced modifications of the antibiotic resistance patterns. These results suggest that adaptation of probiotics to bile could also change their potential impact on intestinal microbiota, and this possibility deserves further attention.

High-Throughput Profiling of Caenorhabditis elegans Starvation-Responsive microRNAs.

MicroRNAs (miRNAs) are non-coding RNAs of ~22 nucleotides in length that regulate gene expression by interfering with the stability and translation of mRNAs. Their expression is regulated during development, under a wide variety of stress conditions and in several pathological processes. In nature, animals often face feast or famine conditions. We observed that subjecting early L4 larvae from Caenorhabditis elegans to a 12-hr starvation period produced worms that are thinner and shorter than well-fed animals, with a decreased lipid accumulation, diminished progeny, reduced gonad size, and an increased lifespan. Our objective was to identify which of the 302 known miRNAs of C. elegans changed their expression under starvation conditions as compared to well-fed worms by means of deep sequencing in early L4 larvae. Our results indicate that 13 miRNAs (miR-34-3p, the family of miR-35-3p to miR-41-3p, miR-39-5p, miR-41-5p, miR-240-5p, miR-246-3p and miR-4813-5p) were upregulated, while 2 miRNAs (let-7-3p and miR-85-5p) were downregulated in 12-hr starved vs. well-fed early L4 larvae. Some of the predicted targets of the miRNAs that changed their expression in starvation conditions are involved in metabolic or developmental process. In particular, miRNAs of the miR-35 family were upregulated 6-20 fold upon starvation. Additionally, we showed that the expression of gld-1, important in oogenesis, a validated target of miR-35-3p, was downregulated when the expression of miR-35-3p was upregulated. The expression of another reported target, the cell cycle regulator lin-23, was unchanged during starvation. This study represents a starting point for a more comprehensive understanding of the role of miRNAs during starvation in C. elegans.

Acquired resistance to bile increases fructose-6-phosphate phosphoketolase activity in Bifidobacterium.

Two Bifidobacterium strains with acquired resistance to bile were used in this study. Significant differences on membrane-associated protein profiles were found between the bile resistant derivatives and their corresponding original strains. One of the major species detected in one of the resistant derivatives had an apparent denatured molecular mass of approximately 90 kDa, and was identified as xylulose-5-phosphate/fructose-6-phosphate phosphoketolase, the key enzyme of Bifidobacterium carbohydrate catabolism. Phosphoketolase activity was considerably higher in membrane preparations and cell-free extracts of the two bile resistant derivatives. This correlated to a greater consumption rate of glucose in resistant strains. Fructose-6-phosphate phosphoketolase activity in the strain Bifidobacterium bifidum CECT4549 and its resistant derivative was found to be partially associated with the cytoplasmic membrane through weak interactions.

Effect of the adaptation to high bile salts concentrations on glycosidic activity, survival at low PH and cross-resistance to bile salts in Bifidobacterium.

Six derivatives with increased resistance to ox gall (MIC: > or = 1% w/v) and one derivative resistant to sodium cholate (MIC: 0.8% w/v) were obtained from more sensitive original Bifidobacterium strains. These microorganisms, and two additional cholate resistant derivatives obtained in a previous study (Int. J. Food Microbiol. 82 (2003) 191), were partially characterised in this study. Acquisition of resistance against a given bile salt, also conferred cross-resistance to other bile salts, and promoted an increase in the survival of these microorganisms at low pH. Bile resistance levels of derivatives were dependent on the external pH so that the resistance was lower at neutral pH values than in acidic environments. In addition, the acquisition of bile resistance induced changes on glycoside-hydrolysing activities of derivatives obtained from five out of eight original strains, with certain activities such as beta-glucosidase showing more than tenfold increases in some of these microorganisms. These data suggest that the exposure to high bile salts concentrations may have induced a synergic response on Bifidobacterium for the adaptation to the conditions of the gastrointestinal tract. This could have improved the survival at low pH in these microorganisms, the resistance to high bile salts concentrations, and the assimilation of non-digestible carbohydrates by the enhancement of some glycoside-hydrolysing activities.