Identification and characterization of a novel alkaline α‑amylase Amy703 belonging to a new clade from Bacillus pseudofirmus.

Alkaline α-amylases are of great interest in desizing processes and detergent industries. Here, an alkaline α-amylase gene amy703 from an alkaliphilic Bacillus pseudofirmus strain was cloned and sequenced. Its encoding product, Amy703, might represent a new clade of α-amylase family, because it shared only 35 % highest identity with all amylases characterized up to date and was not clustered into any subfamilies with amylase activity in glycoside hydrolase family 13.

[Recent developments in L-lactate fermentation by genetically modified microorganisms].

Lactic acid is an important platform chemical. Especially with rapid development of poly (lactic acid) industry, the demand for L-lactic acid is continuously increasing. To further reduce the fermentation costs and improve the robustness of strains from industrial point of view, many modern biotechnological approaches have been applied to strain development.

Efficient production of polymer-grade L-lactate by an alkaliphilic Exiguobacterium sp. strain under nonsterile open fermentation conditions.

In this study, a newly isolated alkaliphile Exiguobacterium sp. strain 8-11-1 was used to produce optically pure L-lactate. With an initial glucose concentration of 80 g/L, a high overall L-lactic acid productivity of 8.

Comparison between Doppler echocardiography and hot-film anemometry in measuring the turbulent shear stress downstream of artificial mitral valves: a methodological study.

Background: Turbulent shear stress (TSS) plays an important role in the research of fluid dynamics of heart valves. This study aimed to perform a quantitative study of TSS downstream of porcine artificial mitral valves in order to verify the correlation of hot-film anemometry (HFA) and Doppler echocardiography combined with computer-aided image analysis for the detection of TSS.

Methods: A porcine model of mitral valve replacement was established.

The alkaline pectate lyase PEL168 of Bacillus subtilis heterologously expressed in Pichia pastoris is more stable and efficient for degumming ramie fiber.

Background: The conventional degumming process of ramie with alkaline treatment at high temperature causes severe environmental pollution. Pectate lyases can be used to remove pectin from ramie in a degumming process with reduced environmental pollution and energy consumption. Pectate lyase PEL168 from Bacillus subtilis has been previously characterized and the protein structure was resolved.

Molecular cloning and heterologous expression of an acid stable xylanase gene from Alternaria sp. HB186.

A new xylanase gene, named xyn186, was cloned by the genome-walking PCR method from the Alternaria sp. HB186. The sequence of xyn186 contains a 748 bp open reading frame separated by one intron with the size of 52 bp.

Distribution change of mast cells in human nasal polyps.

Recent studies have shown that mast cells are involved in pathophysiologic processes of chronic inflammation. However, little is known about the distribution of mast cells in nasal polyps, which is a chronic inflammatory disease of the upper airways. Biopsy specimens from patients with nasal polyps (n = 20) and control patients without nasal polyps (n = 8) were included in this study.

Effects of salts on activity of halophilic cellulase with glucomannanase activity isolated from alkaliphilic and halophilic Bacillus sp. BG-CS10.

Alkaliphilic and halophilic Bacillus sp. BG-CS10 was isolated from Zabuye Salt Lake, Tibet. The gene celB, encoding a halophilic cellulase was identified from the genomic library of BG-CS10.

Contribution of the proinflammatory cytokine IL-18 in the formation of human nasal polyps.

Nasal polyposis is a chronic inflammatory disease of the nasal mucosa. The etiology and the mechanisms of formation of nasal polyps are still not clear. Interleukin (IL)-18 is a novel proinflammatory cytokine that plays important roles in regulating immune inflammatory responses.

Characterization of a thermostable xylanase from an alkaliphilic Bacillus sp.

A xylanase gene (xyn10) from alkaliphilic Bacillus sp. N16-5 was cloned and expressed in Pichia pastoris. The deduced amino acid sequence has 85% identity with xylanase xyn10A from B.

Liquid chromatographic determination of endogenous phytohormones in vegetable samples based on chemical derivatization with 6-oxy(acetylpiperazine) fluorescein.

In phytohormone analysis, mass spectrometry (MS)-based methods are primary and powerful tools. However, complex sample preparation and high cost are problems for their application. As a complement for MS-based methods, a new fluorescent labeling reagent for carboxylic acids, 6-oxy(acetylpiperazine) fluorescein (APF), has been used for the determination of endogenous phytohormones, including indolebutyric acid, 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid.

[Molecular cloning and heterologous expression of a new xylanase gene from Verticillium dahliae].

Objective: Fungus Verticillium dahliae caused greensickness of cotton and xylanase is necessary in this pathogenesis. Cloning xylanase gene from V. dahliae and heterologous expression might obtain new xylanase.

Cloning and enzymatic characterization of a xylanase gene from a soil-derived metagenomic library with an efficient approach.

Screening interesting biocatalysts directly from soil samples is a more convenient and applicable approach than conventional cultivation-dependent ones. In our present work, a soil-derived metagenomic library containing 24,000 transformants was constructed with an efficient strategy for cloning xylanase genes. A gene encoding the enzyme (XynH) able to hydrolyze xylan was obtained.

[Construction of a double functional recombinant strain of Pichia pastoris co-expressing phytase and mannanase and the enzymatic analyses].

Co-expression of phytase and mannanase in Pichia pastoris is a useful way to reduce the production cost in feedstuff industry. Based on the published DNA sequences of phytase gene and mannanase gene, primers were designed and genes phyA and man were cloned by PCR from Aspergillus terreus and the plasmid pHBM1201, respectively. Then the two fragments were treated and inserted into the same expression vector pHBM907C, which contains both the methanol-inducible promoter and the transcription terminator of the AOX1 gene, resulting the plasmid pHBM907C-phyA and the plasmid pHBM907C-man.

[Expression of a laccase gene from Pleurotus ostreatus in Pichia pastoris and characterization of the recombinant enzyme].

A Pleuotus ostreatus laccase gene was cloned by RT-PCR and designated as lccPol. Its sequence was submitted to GenBank with the accession number AY450404 obtained. The open reading frame was transformed into three Pichia pastoris strains GS115, KM71 and SMD1168, respectively, under control of the AOX1 promoter by using the vector pHBM906.

[A methodological study of measuring quantitatively turbulent shear stree downstream of mitral stenosis in vivo using Doppler echocardiography].

In order to establish a method for measuring quantitatively turbulent shear stress (TSS) downstream of mitral stenosis in vivo based on Doppler echocardiography and computer-aided image analysis, we used doppler echocardiography to record the spectrum of flow velocity downstream of mitral valve at several locations in normal persons and in patients with mitral stenosis. With the computer-aided analysis of spectrum images, the magnitude of TSS was measured at the locations. The results demonstrate that no matter how severe the mitral stenosis is, the TSS and relative turbulent intensity(Irel) at the central locations of jet are lower than those at the marginal ones.