Diversity of dimethylsulfide-degrading methanogens and sulfate-reducing bacteria in anoxic sediments along the Medway Estuary,UK

Methane is a powerful greenhouse gas but the microbial diversity mediating methylotrophic methanogenesis is not well-characterized. One overlooked route to methane is via the degradation of dimethylsulfide (DMS), an abundant organosulfur compound in the environment. Methanogens and sulfate-reducing bacteria (SRB) can degrade DMS in anoxic sediments depending on sulfate availability. However, we know little about the underlying microbial community and how sulfate availability affects DMS degradation in anoxic sediments. We studied DMS-dependent methane production along the salinity gradient of the Medway Estuary (UK) and characterized, for the first time, the DMS-degrading methanogens and SRB using cultivation-independent tools. DMS metabolism resulted in high methane yield (39%–42% of the theoretical methane yield) in anoxic sediments regardless of their sulfate content. Methanomethylovorans, Methanolobus and Methanococcoides were dominant methanogens in freshwater, brackish and marine incubations respectively, suggesting niche-partitioning of the methanogens likely driven by DMS amendment and sulfate concentrations. Adding DMS also led to significant changes in SRB composition and abundance in the sediments. Increases in the abundance of Sulfurimonas and SRB suggest cryptic sulfur cycling coupled to DMS degradation. Our study highlights a potentially important pathway to methane production in sediments with contrasting sulfate content and sheds light on the diversity of DMS degraders.     

Global 5-Hydroxymethylcytosine Levels Are Profoundly Reduced in Multiple Genitourinary Malignancies

Solid tumors are characterized by a plethora of epigenetic changes. In particular, patterns methylation of cytosines at the 5-position (5mC) in the context of CpGs are frequently altered in tumors. Recent evidence suggests that 5mC can get converted to 5-hydroxylmethylcytosine (5hmC) in an enzymatic process involving ten eleven translocation (TET) protein family members, and this process appears to be important in facilitating plasticity of cytosine methylation. Here we evaluated the global levels of 5hmC using a validated immunohistochemical staining method in a large series of clear cell renal cell carcinoma (n = 111), urothelial cell carcinoma (n = 55) and testicular germ cell tumors (n = 84) and matched adjacent benign tissues. Whereas tumor-adjacent benign tissues were mostly characterized by high levels of 5hmC, renal cell carcinoma and urothelial cell carcinoma showed dramatically reduced staining for 5hmC. 5hmC levels were low in both primary tumors and metastases of clear cell renal cell carcinoma and showed no association with disease outcomes. In normal testis, robust 5hmC staining was only observed in stroma and Sertoli cells. Seminoma showed greatly reduced 5hmC immunolabeling, whereas differentiated teratoma, embryonal and yolk sack tumors exhibited high 5hmC levels. The substantial tumor specific loss of 5hmC, particularly in clear cell renal cell carcinoma and urothelial cell carcinoma, suggests that alterations in pathways involved in establishing and maintaining 5hmC levels might be very common in cancer and could potentially be exploited for diagnosis and treatment.     

Depressive and anxiety symptoms in the early puerperium are related to increased degradation of tryptophan into kynurenine,a phenomenon which is related to immune activation

There is now some evidence that i) the availability of plasma tryptophan, the precursor of serotonin, is significantly lower in pregnant women at the end of term and the first few days after delivery than in nonpregnant women; and ii) both pregnancy and the early puerperium are accompanied by activation of the inflammatory response system. The aims of the present study were to examine the effects of pregnancy and delivery on plasma kynurenine, a major tryptophan catabolite synthesized after induction of indoleamine-2, 3 dioxygenase (IDO) by pro-inflammatory cytokines. We measured plasma kynurenine and tryptophan and immune markers, such as serum interleukin-6 (IL-6), IL-8 and the leukemia inhibitory factor-receptor (LIF-R) in healthy, nonpregnant and pregnant women at the end of term and one and three days after delivery. Plasma kynurenine was significantly lower in pregnant women at the end of term than in nonpregnant women, findings which may be attributed to lower plasma tryptophan at the end of term. The kynurenine/tryptophan (K/T) quotient was significantly higher in the pregnant women at the end of term and in the early puerperium than in nonpregnant women. In the early puerperium there was a significant increase in plasma kynurenine and the K/T quotient. The increases in plasma kynurenine and the K/T quotient were significantly more pronounced in women whose anxiety and depression scores significantly increased in the puerperium. The changes from the end of term to the early puerperium in plasma kynurenine and the K/T quotient were significantly related to those in the immune markers. It is concluded that 1) lower plasma kynurenine at the end of term is the consequence of lower plasma tryptophan; 2) the increased K/T quotient at the end of term and in the early puerperium indicates inflammation-induced degradation of tryptophan along the kynurenine pathway; and 3) that depressive and anxiety symptoms in the early puerperium are (causally) related to an increased catabolism of tryptophan into kynurenine, a phenomenon which probably results from immune activation.     

Differential display: Identifying genes involved in cardiomyocyte proliferation

An estimated 15,000 different mRNA species are expressed in a typical mammalian cell. The differential expression of mRNAs in both a temporal and cell-specific manner determines the fate of the cell and creates the organism. Analysis of this differential gene expression has become a central aim of many laboratories attempting to understand the mechanisms underlying various biological processes. Currently, we are using a technique called differential display to analyze the differential expression of genes in cardiomyocytes. Differential display is a rapid and powerful technique that was introduced by Liang and Pardee in 1992. Since that time, it has been successfully applied by several groups, and it is quickly becoming a standard method for studying differential gene expression. Here, we present a detailed article discussing the differential display methodology and how we have utilized it to identify potential genes involved in cardiomyocyte proliferation. Furthermore, we have provided a list of materials and supplied examples of data obtained, in an effort to allow the reader to perform the technique with success in their own laboratory.     

BMI and seatbelt use

Objective: Seatbelt use among obese persons may be reduced because seatbelts are uncomfortable. We investigated the association between obesity and seatbelt use with data from the 2002 Behavioral Risk Factor Surveillance System Survey. Research Methods and Procedures: Multivariable logistic regression was used to calculate odds ratios and 95% confidence intervals (CIs) for seatbelt use among overweight (BMI, 25.0 to 29.9), obese (BMI, 30.0 to 39.9), and extremely obese (BMI ≥ 40.0) persons, relative to a non‐overweight/non‐obese reference group (BMI ≤ 24.9), adjusted for age, race, gender, education, and state seatbelt law. Results: Adjusted odds ratios for seatbelt use were 0.89 (95% CI, 0.85 to 0.93) for overweight, 0.69 (0.66 to 0.73) for obese, and 0.45 (95% CI, 0.40 to 0.50) for extremely obese persons. Interaction effects were evident for all covariates, with stronger associations between increasing BMI and decreasing seatbelt use for women, increasing age, higher education, and residence in states with a secondary seatbelt law. There was a linear decrease in seatbelt use with increasing BMI for all subgroups except persons 18 to 24 years old. Discussion: Lack of seatbelt can be added to the list of risk factors associated with obesity. Effective preventive interventions are needed to promote seatbelt use among overweight and obese persons.     

Modulation of lung inflammation by vessel dilator in a mouse model of allergic asthma

Background

Atrial natriuretic peptide (ANP) and its receptor, NPRA, have been extensively studied in terms of cardiovascular effects. We have found that the ANP-NPRA signaling pathway is also involved in airway allergic inflammation and asthma. ANP, a C-terminal peptide (amino acid 99–126) of pro-atrial natriuretic factor (proANF) and a recombinant peptide, NP73-102 (amino acid 73–102 of proANF) have been reported to induce bronchoprotective effects in a mouse model of allergic asthma. In this report, we evaluated the effects of vessel dilator (VD), another N-terminal natriuretic peptide covering amino acids 31–67 of proANF, on acute lung inflammation in a mouse model of allergic asthma.

Methods

A549 cells were transfected with pVD or the pVAX1 control plasmid and cells were collected 24 hrs after transfection to analyze the effect of VD on inactivation of the extracellular-signal regulated receptor kinase (ERK1/2) through western blot. Luciferase assay, western blot and RT-PCR were also performed to analyze the effect of VD on NPRA expression. For determination of VD''s attenuation of lung inflammation, BALB/c mice were sensitized and challenged with ovalbumin and then treated intranasally with chitosan nanoparticles containing pVD. Parameters of airway inflammation, such as airway hyperreactivity, proinflammatory cytokine levels, eosinophil recruitment and lung histopathology were compared with control mice receiving nanoparticles containing pVAX1 control plasmid.

Results

pVD nanoparticles inactivated ERK1/2 and downregulated NPRA expression in vitro, and intranasal treatment with pVD nanoparticles protected mice from airway inflammation.

Conclusion

VD''s modulation of airway inflammation may result from its inactivation of ERK1/2 and downregulation of NPRA expression. Chitosan nanoparticles containing pVD may be therapeutically effective in preventing allergic airway inflammation.     

Building a better neonatal mouse model to understand infant respiratory syncytial virus disease

Background

Respiratory syncytial virus (RSV) is the number one cause of lower respiratory tract infection in infants; and severe RSV infection in infants is associated with asthma development. Today, there are still no vaccines or specific antiviral therapies against RSV. The mechanisms of RSV pathogenesis in infants remain elusive. This is partly due to the fact that the largely-used mouse model is semi-permissive for RSV. The present study sought to determine if a better neonatal mouse model of RSV infection could be obtained using a chimeric virus in which the F protein of A2 strain was replaced with the F protein from the line 19 clinical isolate (rA2-19F).

Methods

Five-day-old pups were infected with the standard laboratory strain A2 or rA2-19F and various immunological and pathophysiological parameters were measured at different time points post infection, including lung histology, bronchoalveolar lavage fluid (BALF) cellularity and cytokines, pulmonary T cell profile, and lung viral load. A cohort of infected neonates were allowed to mature to adulthood and reinfected. Pulmonary function, BALF cellularity and cytokines, and T cell profiles were measured at 6 days post reinfection.

Results

The rA2-19F strain in neonatal mice caused substantial lung pathology including interstitial inflammation and airway mucus production, while A2 caused minimal inflammation and mucus production. Pulmonary inflammation was characterized by enhanced Th2 and reduced Th1 and effector CD8⁺ T cells compared to A2. As with primary infection, reinfection with rA2-19F induced similar but exaggerated Th2 and reduced Th1 and effector CD8⁺ T cell responses. These immune responses were associated with increased airway hyperreactivity, mucus hyperproduction and eosinophilia that was greater than that observed with A2 reinfection. Pulmonary viral load during primary infection was higher with rA2-19F than A2.

Conclusions

Therefore, rA2-19F caused enhanced lung pathology and Th2 and reduced effector CD8⁺ T cell responses compared to A2 during initial infection in neonatal mice and these responses were exacerbated upon reinfection. The exact mechanism is unknown but appears to be associated with increased pulmonary viral load in rA2-19F vs. A2 infected neonatal lungs. The rA2-19F strain represents a better neonatal mouse model of RSV infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0244-0) contains supplementary material, which is available to authorized users.     

Effect of Stearic Acid on Enalapril Stability and Dissolution from Multiparticulate Solid Dosage Forms

Enalapril maleate (EM) is a widely used anti-hypertensive drug which is unstable when mixed with excipients. Enalaprilate and diketopiperazine (DPK) are the main degradation products of enalapril. The in situ preparation of enalapril sodium salt (NaE) has been used to improve drug stability in dosage forms; however, gas release and product rejection ensue when the chemical reaction for obtaining the sodium salt is not completely finished before packaging. This study evaluated the effect of stearic acid (SA) on enalapril stability in microcrystalline cellulose (MCC) pellets containing EM or NaE. MCC pellets containing SA were prepared by the extrusion–spheronization technique and characterized. Enalapril stability and dissolution were then evaluated. DPK and enalaprilate formation were reduced by the addition of SA in pellets containing EM. The overall enalapril degradation in these formulations was lower when compared with pellets containing EM or even NaE prepared without SA. The immediate-release characteristic was maintained by the addition of 5% crospovidone to all the formulations tested. The incorporation of SA into NaE pellets resulted in unexpected enalapril degradation, caused by the interaction of these compounds, as suggested by a thermal analysis of the SA–NaE binary mixture. The findings presented here showed that formulations containing SA could substitute the formation of NaE, since they provide better enalapril stability in solid dosage forms. In addition, it is suggested that the stabilization effects would be observed for other N-carboxyalkyl dipeptide analogs with angiotensin converting enzyme inhibition activity, since these new entities share the same degradation pathway of enalapril.