Functional and structural profiles of GST gene family from three Populus species reveal the sequence-function decoupling of orthologous genes

A common assumption in comparative genomics is that orthologous genes are functionally more similar than paralogous genes. However, the validity of this assumption needs to be assessed using robust experimental data. We conducted tissue-specific gene expression and protein function analyses of orthologous groups within the glutathione S-transferase (GST) gene family in three closely related Populus species: Populus trichocarpa, Populus euphratica and Populus yatungensis. This study identified 21 GST orthologous groups in the three Populus species. Although the sequences of the GST orthologous groups were highly conserved, the divergence in enzymatic functions was prevalent. Through site-directed mutagenesis of orthologous proteins, this study revealed that nonsynonymous substitutions at key amino acid sites played an important role in the divergence of enzymatic functions. In particular, a single amino acid mutation (Arg39→Trp39) contributed to P. euphratica PeGSTU30 possessing high enzymatic activity via increasing the hydrophobicity of the active cavity. This study provided experimental evidence showing that orthologues belonging to the gene family have functional divergences. The nonsynonymous substitutions at a few amino acid sites resulted in functional divergence of the orthologous genes. Our findings provide new insights into the evolution of orthologous genes in closely related species.

Influence of Aspergillus fumigatus conidia viability on murine pulmonary microRNA and mRNA expression following subchronic inhalation exposure

BACKGROUND

Personal exposure to fungal bioaerosols derived from contaminated building materials or agricultural commodities may induce or exacerbate a variety of adverse health effects. The genomic mechanisms that underlie pulmonary immune responses to fungal bioaerosols have remained unclear.

OBJECTIVE

The impact of fungal viability on the pulmonary microRNA and messenger RNA profiles that regulate murine immune responses was evaluated following subchronic inhalation exposure to Aspergillus fumigatus conidia.

METHODS

Three groups of naïve B6C3F1/N mice were exposed via nose-only inhalation to A. fumigatus viable conidia, heat-inactivated conidia (HIC), or HEPA-filtered air twice a week for 13 weeks. Total RNA was isolated from whole lung 24 and 48 h postfinal exposure and was further processed for gene expression and microRNA array analysis. The molecular network pathways between viable and HIC groups were evaluated.

RESULTS

Comparison of data sets revealed increased Il4, Il13 and Il33 expression in mice exposed to viable vs. HIC. Of 415 microRNAs detected, approximately 50% were altered in mice exposed to viable vs. HIC 48 h postexposure. Significantly down-regulated (P ≤ 0.05) miR-29a-3p was predicted to regulate TGF-β3 and Clec7a, genes involved in innate responses to viable A. fumigatus. Also significantly down-regulated (P ≤ 0.05), miR-23b-3p regulates genes involved in pulmonary IL-13 and IL-33 responses and SMAD2, downstream of TGF-β signalling. Using Ingenuity Pathway Analysis, a novel interaction was identified between viable conidia and SMAD2/3.

CONCLUSIONS AND CLINICAL RELEVANCE

Examination of the pulmonary genetic profiles revealed differentially expressed genes and microRNAs following subchronic inhalation exposure to A. fumigatus. MicroRNAs regulating genes involved in the pulmonary immune responses were those with the greatest fold change. Specifically, germinating A. fumigatus conidia were associated with Clec7a and were predicted to interact with Il13 and Il33. Furthermore, altered microRNAs may serve as potential biomarkers to evaluate fungal exposure.

Isolation and determination of bile acids

In this article, the methods of isolation and determination of bile acids are reviewed. Methods for separation of bile acids from cattle and pig bile are given in detail. Isolation of a mixture of cholic acid and deoxycholic acids from cattle bile and their subsequent purification are described. The isolation and purification of hyodeoxycholic acid and other components of pig bile are also included. Methods for the determination of bile acids in various biological samples are reviewed, including enzyme assays, radioimmunoassay, enzyme immunoassay and chromatographic methods. Among chromatographic methods, separation and determination of bile acids by thin-layer chromatography, gas chromatography and high performance liquid chromatography are reviewed. Particular attention is given to the use of high performance liquid chromatography since this has recently been the most commonly applied method for the separation and determination of bile acids.

[Study on major metabolites of 3H-1,2-dihydro-2-(4-methylphenylamino)-methyl-1-pyrrolizinone in rabbits]

The metabolites of a 750 mg oral dose of Z-47 [3H-1, 2-dihydro-2-(4-methylphenylamino) methyl-1-pyrrolizinone], a new anti-inflammatory and analgesic agent, in rabbit urine were separated and detected with high performance liquid chromatographic method. On basis of the chromatographic behavior of Z-47 metabolites and biotransformation pathways of drugs with partial structure of Z-47, the carboxylic derivative of Z-47 [4-(3H-1, 2-dihydro-1-pyrrolizinone-2-methylamino) benzoic acid] was proposed as a potential metabolite so that the compound was synthesized. The authentic substance was then compared with one of the metabolites by the chromatographic retention time and the ratio of their UV-absorbances at two wavelengths. The enzyme-hydrolyzed product of another metabolite was also analysed. It was consequently confirmed that the carboxylic derivative of Z-47 and its acyl beta-D-glucuronide are major metabolits of Z-47 in rabbits.

Anti-arrhythmic effects of captopril on coronary occlusion and reperfusion periods in pigs

Anti-arrhythmic effects of captopril (Cap) were studied in the anesthetized pigs using a reversible balloon catheter. Results showed that Cap did not exert any influence on the weight percentage of ischemic area to the whole left ventricle, on the levels of serum creatine kinase (CK) and creatine kinase isozyme (CK-MB), nor on the incidence and duration of transient and persistent tachycardia, but reduced the incidence of ventricular fibrillation (2/12, 1/12 in high-dose group pigs treated with Cap 6 mg.kg-1 in the first 10 min, 25 micrograms.kg-1.min-1 in the later 90 min and 12/21, 11/21 in control group treated with normal saline through the occlusion and reperfusion periods, respectively, P < 0.05). It was suggested that Cap did not exhibit direct (or non-specific, if any) effects on anti-arrhythmias.

[The adverse effect of catheter ablation on the AV junction in experimental dogs]

The purpose of this study was to assess the adverse effects of catheter electrical ablation. Eighteen anesthetized mongrel dogs received 10-400 J of DC countershocks one to five times in each of them near the region of AVJ. Complete AV block was established, no pacemaker was implanted. Electrical unstability was seen nearly in all. Among the date of observation (1-547 days), 16 dogs died spontaneously and the other two were killed. Gross and microscopic examination revealed that cardiac damage produced by DC shock was diffusely spread over the endocardium/valve, myocardium and epicardial layers. The prominent lesions of the acute stage were myocytolysis and/or necrosis of myocardium/endocardium. In chronic stage, diffuse fibrosis and other types of tissue degeneration were revealed, some dogs had both acute and chronic lesions at the same time. Two dogs with perforated aortic valve revealed an elevation of PAEDP, one of them developed marked right heart failure and ascites. We proposed that the acute submicroscopic injury induced by DC shock may progress to a diffuse and irreversible pathologic changes. Therefore, the chronic adverse effects of catheter ablation should be evaluated carefully.