[Effects of Freezing and Thawing Treatments on Beef Protein Secondary Structure Analyzed with ATR-FTIR].

In order to further clarify the influence mechanism of different freezing temperature on meat quality in meat industry. The effects of freezing at -18, -23 and -38 ℃ on the stability of protein secondary structures of beef were studied. The attenuated total reflectance Fourier transfer infrared spectroscopy(ATR-FTIR)technique and automatic deconvolution, curve fitting and other calculation and analysis methods were used to analyze the changes of beef myofibrillar protein infrared spectra and secondary structures during -18, -23 and -38 ℃ freezing-thawing processes. ATR-FTIR results showed that the peak high and peak area of infrared spectra of beef myofibrillar protein in the freezing-thawing processes were changed, and the red shift or blue shift of wavenumbers occurred. The intensities of the absorption peak of 3 500~3 300 cm-1 in the infrared spectra of the frozen-thawed beef were reduced or even disappeared. This indicated that the intramolecular and intermolecular hydrogen bonding interactions, which formed by the bound water O­H group and the amino acid CO group, in thawed beef myofibrillar protein were broken. In other words, freezing can result in the destruction of beef myofibrillar protein secondary structures and protein advanced structures unfolded. Once the beef is thawed, the unfolded protein would reaggregation, and protein renaturation. Freezing could affect the stability of beef myofibrillar protein, the relative content of α-helix, ß-sheet, and ß-turn of beef myofibrillar protein were decreased, and the α-helix and ordered structures changed to the randon coil and disordered structures. After thawing, the increase of ß-sheet relative content of beef myofibrillar protein at -38 ℃ was greater than that of -23 and -18 ℃. The stability of -38 ℃ frozen beef myofibrillar protein was the best, and the protein renaturation was also the best after thawing. That is, the lower the freezing temperature, the lower the measure of freezing denaturation of beef myofibrillar protein, and the better the secondary structures stability of beef myofibrillar protein. The experimental study based on the actual production condition of the meat industry. And the effect of freezing temperatures on beef protein denaturation and the possible mechanism were revealed at the micro-aspect. It can be seen that the ATR-FTIR technology can reflect the changes of protein secondary structures in the process of freezing-thawing of beef, and reveal the regularity of beef protein denaturation, which can be used to identify and evaluate the quality of frozen meat. The experimental results provide a reference for the freezing preservation process and a method for the quality evaluation of meat.

Chemical Synthesis of Proteins Using an o-Nitrobenzyl Group as a Robust Temporary Protective Group for N-Terminal Cysteine Protection.

We report here a robust and practical strategy for chemical protein synthesis using an o-nitrobenzyl group as a temporary protective group for an N-terminal cysteine residue of intermediate hydrazide fragments. By reinvestigating the photoremoval of an o-nitrobenzyl group, we establish a robust and reliable strategy for its quantitative photodeprotection. The o-nitrobenzyl group is completely stable to oxidative NaNO2 treatment and has been applied to the convergent chemical synthesis of programmed death ligand 1 fragment, providing a practical avenue for hydrazide-based native chemical ligation.

Acupuncture on treating asthma: A protocol for systematic review and meta analysis.

BACKGROUND: Asthma is one of the most common chronic diseases in the world, with approximately 300 million asthma patients worldwide. The mortality rate of asthma is 1.6 to 36.7 / 100,000 people, and China has become one of the countries with the highest asthma death rate in the world. Asthma is a chronic allergic airway inflammatory disease. Patients with this disease may have symptoms such as cough, wheezing, and difficulty breathing. For many years, Western medicine has mainly used anti-inflammatory, anti-bronchial spasm, asthma, cough and oxygen to treat this disease, but the effect is not good. Clinical studies in recent years have found that the use of acupuncture in the treatment of bronchial asthma has a good clinical application prospect. This study was conducted to study the effect of using acupuncture to treat asthma. METHODS AND ANALYSIS: We will search for PubMed, Cochrane Library, AMED, EMbase, WorldSciNet; Nature, Science online and China Journal Full-text Database (CNKI), China Biomedical Literature CD-ROM Database (CBM), and related randomized controlled trials included in the China Resources Database. The time is limited from the construction of the library to November 2019. We will use the criteria provided by Cochrane 5.1.0 for quality assessment and risk assessment of the included studies, and use the Revman 5.3 and Stata13.0 software for meta-analysis of the effectiveness, recurrence rate, and symptom scores of asthma. ETHICS AND DISSEMINATION: This systematic review will evaluate the efficacy and safety of acupuncture for asthma. Because all of the data used in this systematic review and meta-analysis has been published, this review does not require ethical approval. Furthermore, all data will be analyzed anonymously during the review process Trial.

Isolation and characterization of LHT-type plant amino acid transporter gene from Panax ginseng Meyer.

A lysine histidine transporter (LHT) cDNA was isolated and characterized from the roots of Panax ginseng, designated PgLHT. The cDNA is 1,865 bp with an open reading frame that codes for a protein with 449 amino acids and a calculated molecular mass of 50.6 kDa with a predicted isoelectric point of 8.87. Hydropathy analysis shows that PgLHT is an integral membrane protein with 9 putative membrane-spanning domains. Multiple sequence alignments show that PgLHT shares a high homology with other plant LHTs. The expression profile of the gene was investigated by real-time quantitative polymerase chain reaction during various chemical treatments. PgLHT was up-regulated in the presence of abscisic acid, salicylic acid, methyl jasmonate, NaCl, and amino acids. To further explore the function of PgLHT gene, full-length cDNA of PgLHT was introduced into P. ginseng by Agrobacterium rhizogenes A4. The overexpression of PgLHT in the hairy roots led to an obviously increase of biomass compared to the controls, and after addition of the amino acids, the overexpressed-PgLHT hairy roots grew more rapidly than untreated controls during early stage of the culture cycle. The results suggested that the PgLHT isolated from ginseng might have role in the environmental stresses and growth response.

Serum, liver, and kidney proteomic analysis for the alloxan-induced type I diabetic mice after insulin gene transfer of naked plasmid through electroporation.

Gene therapy has been reported to be effective in treating diabetes mellitus (DM), while little has been found out about the functional protein changes since. The liver and kidney play important roles in glucose absorption, metabolism, and excretion. Changes in the two organs may reflect pathologic alterations during DM, while the serum has a direct connection with most organs and pathological changes. We used alloxan to induce diabetic mice, electrotranferred the insulin gene into their sural muscles, and discovered that their blood glucose decreased to normal level. Consequently, proteomic approaches were applied to evaluate protein changes in the liver, kidney, and serum of normal, diabetic, and gene transferred mice. Forty-three proteins were found either up-regulated or down-reglulated in the liver, kidney, and serum of the alloxan-induced type I diabetic mice. Only five proteins in the liver, five proteins in the kidney, and seven proteins in the serum of diabetic mice were found to be back-regulated to normal levels after gene transfer. These back-regulated proteins are involved in lipid and glucose metabolism, associated with phosphorylation, signal transduction, oxidation, and immune inflammation. Our findings might promote a better understanding for the mechanism of DM, and provide novel targets for estimating the effects of gene therapy.

A comprehensive study of optimal conditions for naked plasmid DNA transfer into skeletal muscle by electroporation.

Efficient gene transfer is a key factor in gene therapy. Reducing the damage caused by gene transfer to muscle by electroporation is very important for its clinical application. Extensive investigation of optimal conditions for gene transfer by electroporation is required. The parameters used for electroporation, including plasmid concentration; injection volume; the plasmid dose of the injection; the concentration of saline media; the size of plasmid DNA; the age of the mice; the lag time between plasmid injection and electroporation; and the effect of repeated gene transfer by electroporation, were systematically investigated in the present study. The efficiencies of gene transfer by electroporation in normal and rodent models of diabetes were also evaluated. We found that electroporation used for non-viral gene transfer could be repeated in the same place in the muscle, but the expression efficiency was closely related to the muscle damage. Increasing pulse times could enhance the efficiency of gene transfer with a lower strength of electric field. It was better to use a higher plasmid concentration than to use a larger dose of plasmid and repeated injection to achieve a high level of transgene expression. Optimal conditions varied in different animal models, being milder for diabetic mice than for normal mice, and it was also shown that the conditions that worked well on these small rodents were not necessarily suitable for larger animals. Our results provide a comprehensive view of the factors that affect the efficiency of gene transfer into skeletal muscle by electroporation.