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Protein is the main component of aquatic feed. Fish meal, as the main protein raw material, has seen a rapid increase in price in recent years. So the development of new protein ingredients has become a hot issue in aquaculture. However, the new protein ingredients contain anti-nutrition factors, which are not conducive to the digestion of aquatic animals. Therefore, it is necessary to degrade anti-nutrition factors, release nutrients, and improve the nutritional value through enzymatic hydrolysis. The paper discusses the status of enzymatic hydrolysis of different protein raw materials and their application as substitutes for fish meal in aquaculture, to provide a reference for the extensive application of enzymatic hydrolysis protein raw materials in aquatic feed. [ABSTRACT FROM AUTHOR]

Aims: Accumulating evidence suggests that Porphyromonas gingivalis is closely associated with the development of various chronic inflammatory diseases, particularly periodontitis. This study investigated the antibacterial activity and action mechanism of a novel antimicrobial peptide (AMP), DP7, against P. gingivalis. Methods and Results: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for DP7 were determined via a broth microdilution method, revealing an MIC of 8 μg ml−1 and MBC of 32 μg ml−1. Growth inhibition and killing assays confirmed the bactericidal effect of DP7, and treatment with DP7 at MBC eliminated P. gingivalis within 8 h. DP7 had a low cytotoxic effect against human cells. Transmission electron microscopy revealed that DP7 destroyed the bacterial membrane, and confocal laser scanning microscopy revealed its inhibitory effect on P. gingivalis biofilms. Quantitative reverse transcription‐polymerase chain reaction revealed DP7‐mediated inhibition of several virulence factor genes, partially explaining its antibacterial mechanism. Conclusions: DP7, a novel AMP with low mammalian cytotoxicity, inhibits both planktonic and biofilm forms of P. gingivalis by destroying the bacterial membrane and reducing virulence factor gene expression. Significance and Impact of the Study: DP7 has potential clinical application in the prevention and treatment of P. gingivalis‐associated diseases. [ABSTRACT FROM AUTHOR]

An ideal bone repair scaffold is expected to possess superior architectural characteristics to facilitate the adhesion, proliferation, and migration of bone‐repair‐related cells, while excluding nonosteogenic cells and fibrous tissues from interfering with normal bone regeneration. Unfortunately, such scaffold material has rarely been reported. Herein, nanocomposite scaffolds with a radially ordered porous structure are presented, manufactured using a modified directional freeze‐casting method, and are promising bone defect repair materials to satisfy this requirement. The prepared nanocomposite scaffolds consist of a natural bio‐macromolecule, chitosan, and bioactive hydroxyapatite nanoparticles derived from porcine cortical bone, demonstrating favorable biocompatibility and biological functions. Both in vitro cell studies and in vivo animal studies reveal the great superiority of the radially oriented porous structure of the scaffolds in guiding bone regeneration, while simultaneously preventing the invasion of surrounding nonosteogenic cells and fibrous tissue, compared to the axially oriented porous structure. This work indicates the distinctive potential of radially oriented porous scaffolds for repairing tabular and lacunar bone defects. [ABSTRACT FROM AUTHOR]

Short-chain chlorinated paraffins are persistent organic pollutants, and chlorinated paraffins were widely used as sizing agent in the paper industry. In order to investigate the levels and risk assessment of short-chain and medium-chain chlorinated paraffins in the paper mill plant, the surface soil and soil of different depths were collected.The concentrations, congener group profiles of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in soil were determined by two-dimensional gas chromatography coupled with electron capture-negative ion mass spectrometry. The SCCPs and MCCPs concentrations were 42-3853 ng·g -1 and 34-2091 ng·g -1 . The chlorine contents were 59.9%-61.9% and 48.7%-52.8%. The concentrations of SCCPs and MCCPs were different in the soil collected in different sampling site. The concentration of SCCPs and MCCPs were relatively higher in soil of sewage treatment area and coating area. The CP levels in soil from the paper mill plant were at a high level compared with those in other regions. C 10 Cl 6-7 and C 14-15 Cl 5 were the main congener groups in most soil samples. The results of principal component analysis showed that the CP52 commercial products may be sources of SCCPs and MCCPs in the soil. The risk quotient (RQ) for SCCPs and MCCPs were assessed in soil of paper mill plant. The results showed that the RQ values for SCCPs in soil ranged from 0.01 to 0.73 which are the medium risk, and the RQ values for MCCPs in soil ranged from 0 to 0.07, which are the low risk. The human exposure values of children and adults are lower than TDI[10 μg·(kg·d) -1 ] in both cases. The health risks caused by non-dietary exposure under paper mill area are low.

Background: Xylanase can replace chemical additives to improve the volume and sensory properties of bread in the baking. Suitable baking xylanase with improved yield will promote the application of xylanase in baking industry. The xylanase XYNZG from the Plectosphaerella cucumerina has been previously characterized by heterologous expression in Pichia pastoris. However, P. pastoris is not a suitable host for xylanase to be used in the baking process since P. pastoris does not have GRAS (Generally Regarded As Safe) status and requires large methanol supplement during the fermentation in most conditions, which is not allowed to be used in the food industry. Kluyveromyces lactis, as another yeast expression host, has a GRAS status, which has been successfully used in food and feed applications. No previous work has been reported concerning the heterologous expression of xylanase gene xynZG in K. lactis with an aim for application in baking., Results: The xylanase gene xynZG from the P. cucumerina was heterologously expressed in K. lactis. The recombinant protein XYNZG in K. lactis presented an approximately 19 kDa band on SDS-PAGE and zymograms analysis. Transformant with the highest halo on the plate containing the RBB-xylan (Remazol Brilliant Blue-xylan) was selected for the flask fermentation in different media. The results indicated that the highest activity of 115 U/ml at 72 h was obtained with the YLPU medium. The mass spectrometry analysis suggested that the hydrolytic products of xylan by XYNZG were mainly xylobiose and xylotriose. The results of baking trials indicated that the addition of XYNZG could reduce the kneading time of dough, increase the volume of bread, improve the texture, and have more positive effects on the sensory properties of bread., Conclusions: Xylanase XYNZG is successfully expressed in K. lactis, which exhibits the highest activity among the published reports of the xylanase expression in K. lactis. The recombinant XYNZG can be used to improve the volume and sensory properties of bread. Therefore, the expression yield of recombinant XYNZG can be further improved through engineered strain containing high copy numbers of the XYNZG, and optimized fermentation condition, making bread-baking application possible.

In this paper, a simple universal high-throughput method of constructing the vectors was developed. It could add proper adapter when the PCR primers were designed, and the purpose fragments were cloned by PCR, and the various complementary sticky ends were created by T4 DNA polymerase's 3' -exodeoxyribonuclease activity. If all these fragments were put together with DNA ligase, they would recombinate in an orientation. If they had been transformated, the tansformants would be identified. Let's take the Oryza sativa single-cross homologous recombination chloroplast expression vector pRSMGA which was constructed with seven fragments as an example, if the vector pRSMGA was constructed in using the method what had mentioned, only twice recombination and transformation would be done. Scores of experiments had proved that it is a simple universal high-throughput novel method to construct the complicated vectors, which has not appeared in the periodical.

According to the published DNA sequence, a serial of elements for constructing the tobacco chloroplast multicistron site integrating expression vectors have been cloned by PCR technique, which include Prrn (a modified plastid ribosomal RNA operon promoter), psbA3' (the 3' region of the plastid psbA gene), aadA gene (encoding aminoglycoside 3'-adenylytransferase), man gene (encoding mannase), gfp gene (encoding green fluorescence protein) and tobacco chloroplast high-frequency homologous recombination ctDNA fragment (psaA/psbC, 3463 bp) (Fig.2). A tobacco chloroplast multicistron expression vector pLM4 (Fig.1) (-psaA-Prrn-SD-man-SD-gfp-SD-aadA-psbA3'- psbC-) was constructed with these elements. Then the tobacco leaves were bombarded 5 times with gold particles coated with the vector pLM4. After growing on the screening medium, the function of aadA gene was identified (Fig.3), and the function of gfp gene was confirmed by laser scanner (Fig.4), the expression of man was identified by Western blot (Fig.5). All these genes man, gfp and aadA being integrated in the tobacco chloroplast genome DNA were confirmed by PCR (Fig.6). And the multicistron expression cassette integrating in tobacco chloroplast genome DNA was confirmed by RFLP (Fig.7). All these showed that the three genes in the tomato vector pLM4 were expressed in tobacco chloroplast genome DNA.

A strain containing alkaline mannanase gene was isolated from soil by functional plates and the genome library was constructed. From it a mannanase gene TM1 was acquired and was sequenced. The BLAST analysis showed a lower-than-60% similarity of the amino acid sequence to those in GenBank and proved TM1 to be a new mannanase gene (GenBank accession number AY623903). The new gene without signal peptide was cloned into the Pichia pastoris expression vector pHBM905C. The recombinant plasmid pHBM1201 was digested by Sal I and transformed into Pichia pastoris KM71, GS115, SMD1168, respectively. All of the recombinant Pichia pastroris strains containing pHBM1201 secreted functional beta-mannanase. Because of its high mass of expression, the recombinant Pichia pastoris SMD1168-3 containing pHBM1201 was induced at shake flasks. The optimal temperature and pH of the beta-mannanase produced by the recombinant strains were 55 degrees C and 7.5, respectively. The enzymatic activity for konjak powder reached 41.8 with a half life of one hour. After keeping at 80 degrees C for 5 min, the enzymatic activity declined from 77% to 11% and the enzymatic activity could recover up to more than 60% when the temperature descended to 55 degrees C.