Background
Severe Mycoplasma pneumoniae pneumonia (MPP) may develop with long‐term pulmonary outcomes despite treatment with macrolides. Combined treatment with glucocorticoids can improve this ...outcome, though the optimal dosage is unknown. The aim of this study was to investigate the effects of low‐ and high‐dose methylprednisolone in reducing the percentage of long‐term pulmonary outcomes for children with severe MPP.
Methods
A randomized, single‐blind, parallel‐controlled, multicenter clinical trial, methylprednisolone for children with severe M. pneumoniae pneumonia (MCMP), is being conducted in China. Pediatric patients (≤18 years of age, expected number = 402) admitted to the hospital with a clinical diagnosis of severe MPP and fulfilling inclusion and exclusion criteria are randomized (ratio of 1:1) to either a low‐dose (2 mg/kg/d) or high‐dose (10 mg/kg/d) methylprednisolone treatment group for 3 days followed by tapering of methylprednisolone over 12 days and combined with azithromycin. The primary composite outcome will be incidence of atelectasis, bronchiectasis, or bronchiolitis obliterans at 6‐months after treatment. Secondary outcomes include recovery time of patient temperature, proportion of pulmonary lesions absorbed, changes of mucosa identified by bronchoscopy, length of hospital stay, pulmonary function and number of participant(s) needing intensive care. Assessments will be made at baseline, post‐treatment and at 1‐month, 3‐month and 6‐month follow‐ups.
Discussion
This is the first randomized clinical trial designed to evaluate the safety and efficacy of low‐ versus high‐dose methylprednisolone for reducing long‐term pulmonary outcomes in pediatric patients with severe MPP. The results of this study will provide scientific evidence to guide clinical practice for the treatment of severe MPP. Trial registration: This study is registered at ClinicalTrials.gov (NCT02303587).
Biomass-degrading enzymes produced by microorganisms have a great potential in the processing of agricultural wastes. In order to produce suitable biomass-degrading enzymes for releasing sugars and ...aroma compounds from tobacco scraps, the feasibility of directly using the scraps as a carbon source for enzyme production was investigated in this study. By comparative studies of ten fungal strains isolated from tobacco leaves,
Aspergillus brunneoviolaceus
Ab-10 was found to produce an efficient enzyme mixture for the saccharification of tobacco scraps. Proteomic analysis identified a set of plant biomass-degrading enzymes in the enzyme mixture, including amylases, hemicellulases, cellulases and pectinases. At a substrate concentration of 100 g/L and enzyme dosage of 4 mg/g, glucose of 17.6 g/L was produced from tobacco scraps using the crude enzyme produced by
A. brunneoviolaceus
Ab-10. In addition, the contents of 23 volatile molecules, including the aroma compounds 4-ketoisophorone and benzyl alcohol, were significantly increased after the enzymatic treatment. The results provide a strategy for valorization of tobacco waste by integrating the production of biomass-degrading enzymes into the tobacco scrap processing system.
There are abundant crop straws in Chinese rural areas, but they are loose structure, low energy density and scattered distribution. Biomass densification technology is one of the effective ways to ...solve these problems. So the paper proposes a novel distributed heating/centralized monitoring mode of the biomass briquette fuel for rural areas. The mode includes the energy service station, the internet platform and the farmer households. A bidirectional C2S (Customer to Supplier) relationship between the energy service station and the farmer households is formed. The biomass briquette fuels are bartered using the crop straws instead of using money between the farmer households and the energy service station. The optimal service radius is calculated in different climate rons. The results are 4.75 km in extremely cold ron, 1.71 km in cold plain ron, 2.36 km in cold mountain ron. The use-scale of 1000 households is regarded as the standard for the promotion and application of the mode. The sensitivity analysis is that briquetting cost is the peak. At last, some suggestions are proposed, which will promote the future development of the briquette heating in China.
•A mode of distributed heating/centralized monitoring is proposed in China.•A bidirectional C2S (Customer to Supplier) relationship is formed.•The optimal use-scale and optimal radius of the mode are calculated.•The “Internet + biomass energy network” is builds in rural area.•Some policies are suggested for the further development of biomass heating.
Aims
The aim of this article is to study the functional features of Penicillium oxalicum transcriptional activator XlnR.
Methods and Results
The yeast reporter system was used to identify ...transcriptional activation domain of XlnR in P. oxalicum. The expression cassette was introduced into the xlnR locus of P. oxalicum by homologous recombination. In this study, several putative structural domains in P. oxalicum XlnR were predicted by bioinformatics analysis, and the transcriptional activation domain (351–694 region) was identified in XlnR relying on reporter gene system in yeast. In addition, the amino acid at XlnR 871 site (alanine) located in the regulatory region could influence the regulatory activity of XlnR directly. When the alanine at XlnR 871 site was replaced by stronger hydrophobic amino acid (e.g. valine or isoleucine), the regulatory activity will be greatly improved, especially for the regulation of hemicellulase genes expression. When alanine at XlnR 871 site was mutated to a hydrophilic amino acid (e.g. aspartic acid or arginine), the regulatory activity of XlnR will be reduced.
Conclusions
The 351–694 region of P. oxalicum XlnR was identified as transcriptional activation domain, and the regulatory activity of XlnR was greatly influenced by hydrophobicity of amino acid at 871 site of XlnR in P. oxalicum.
Significance and Impact of the Study
The results will provide an effective target site to regulate the activity of XlnR and improve cellulase production of P. oxalicum.
Enzymatic conversion of corn fiber to fermentable sugars is beneficial to improving the economic efficiency of corn processing. In this work, the filamentous fungus Penicillium oxalicum was found to ...secrete enzymes for efficient saccharification of un-pretreated corn fiber. Separate engineering of transcriptional activators ClrB, XlnR, and AraR led to enhanced production of different sets of lignocellulolytic enzymes. Particularly, the enzymes produced by XlnR- and AraR-engineered strains showed a synergistic effect in corn fiber saccharification. Combinatorial engineering of all three activators generated a strain MCAX with 3.1- to 51.0-fold increases in lignocellulolytic enzyme production compared with the parent strain. In addition, the enzymes of strain MCAX released significantly more fermentable sugars from corn fiber than those of the parent strain at the same protein dosage. The results suggest that this strain has potential for on-site production of enzymes for corn fiber saccharification.
Lignocellulolytic enzymes are the main enzymes to saccharify lignocellulose from renewable plant biomass in the bio-based economy. The production of these enzymes is transcriptionally regulated by ...multiple transcription factors. We previously engineered
for improved cellulase production via manipulation of three genes in the cellulase expression regulatory network. However, the potential of combinational engineering of multiple regulators and their targets at protein abundance and activity levels has not been fully explored.
Here, we verified that a point mutation XlnR
in transcription factor XlnR enhanced the expression of lignocellulolytic enzymes, particularly hemicellulases, in
. Then, overexpression of XlnR
with a constitutive
promoter was combined with the overexpression of cellulase transcriptional activator ClrB and deletion of carbon catabolite repressor CreA. The resulted strain RE-7 showed 8.9- and 51.5-fold increased production of cellulase and xylanase relative to the starting strain M12, respectively. Further overexpression of two major cellulase genes
-
and
enabled an additional 13.0% improvement of cellulase production. In addition, XlnR
led to decreased production of β-glucosidase and amylase, which could be attributed to the reduced transcription of corresponding enzyme-encoding genes.
The results illustrated that combinational manipulation of the involved transcription factors and their target genes was a viable strategy for efficient production of lignocellulolytic enzymes in filamentous fungi. The striking negative effect of XlnR
mutation on amylase production was also highlighted.
Display omitted
•Engineered Trichoderma reesei strain produces cellulases and xylanases on glucose.•Boosting of hydrolysis efficiency by expressing heterologous β-glucosidases.•High-level production ...of lignocellulolytic enzymes using lignocellulosic hydrolysate.•On-site enzyme production requires the recycling of 3.1% corn stover hydrolysate.
The cost-effective production of lignocellulose-saccharolytic enzymes is crucial for the bioconversion of plant biomass into fuels and chemicals. The integrated mode for producing these enzymes using lignocellulosic feedstocks as natural inducers has a cost advantage; however, enzyme production level is limited because of the solid-state and complex composition of the raw materials. This study aimed to establish an innovative process for the integrated production of lignocellulolytic enzymes using lignocellulosic hydrolysate as the carbon source. The cellulase-producing workhorse Trichoderma reesei was reprogrammed by combinatorial engineering of transcription factors and the introduction of heterologous β-glucosidases. This enabled inducer-independent production of a complete lignocellulose-saccharolytic enzyme cocktail using lignocellulose-derived monosaccharides as sole carbon source. Via continuous feeding of the enzymatic hydrolysate of pretreated corn stover, crude enzymes with filter paper enzyme activity of 60.4 U/ml and β-glucosidase activity of 503 U/ml were produced. Crude fermentation broth can be used directly to prepare hydrolysates, enabling nex-round enzyme production by recycling 3.1% of the hydrolysate. These results demonstrate a closed-loop strategy for integrated enzyme production using internally produced lignocellulosic sugars from biorefinery plants.
Hyphal morphology is considered to have a close relationship with the production level of secreted proteins by filamentous fungi. In this study, the gul1 gene, which encodes a putative mRNA-binding ...protein, was disrupted in cellulase-producing fungus Trichoderma reesei. The hyphae of Δgul1 strain produced more lateral branches than the parent strain. Under the condition for cellulase production, disruption of gul1 resulted in smaller mycelial clumps and significantly lower viscosity of fermentation broth. In addition, cellulase production was improved by 22% relative to the parent strain. Transcriptome analysis revealed that a set of genes encoding cell wall remodeling enzymes as well as hydrophobins were differentially expressed in the Δgul1 strain. The results suggest that the regulatory role of gul1 in cell morphogenesis is likely conserved in filamentous fungi. To our knowledge, this is the first report on the engineering of gul1 in an industrially important fungus.
In Arabidopsis and rice, the glycosyltransferase (GT) 43 family is involved in xylan synthesis. However, there have been limited reports on the study of the TaGT43 family in wheat. In this study, 28 ...TaGT43 family members were identified in wheat (Triticum aestivum L.) and clustered into three major groups based on the similarity of amino acid sequences. The results of the TaGT43 family's conserved motif and gene structure analyses agree with this result. Collinearity analysis revealed segmental duplications mainly promoted TaGT43 family expansion. cis-Acting element analysis revealed that the TaGT43 genes were involved in the light response, phytohormone response, abiotic/biotic stress response, and growth and development. The TaGT43 family showed a tissue-specific expression pattern, primarily expressed in roots and stems. Besides, the transcriptional and expression levels of multiple TaGT43 genes were upregulated during the infection of F. graminearum. According to metabolomics studies, F. graminearum infection affected the phenylpropanoid biosynthesis pathway in wheat, a critical factor in cell wall construction. Furthermore, GO enrichment analysis indicated that the TaGT43 genes play a significant role in cell wall organization. Based on these results, it may be concluded that the TaGT43 family mediates cell wall organization in response to F. graminearum infection.
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