[Results analysis of mNGS applied to infectious diseases]

The application of metagenomic second-generation sequencing (mNGS) is shifting from research to clinical laboratories due to rapid technological advances and significant cost reductions. Although many studies and case reports have confirmed that the success of mNGS in improving the prevention, diagnosis, treatment and tracking of infectious diseases, there are still some obstacles that must be overcome. The results of mNGS show all the possible pathogens in the sample, however, in the face of thousands of microbes that can infect humans, it remains challenging to accurately identify the key pathogens. So far, there is no unified interpretation standard for mNGS in clinical practice. This article reviews the interpretation of mNGS results for pathogen infection in different systems, the clinical interpretation and application regulations of mNGS results, and the challenges of mNGS interpretation in pathogen diagnosis.

[Comparison and application of postprandial and fasting blood lipid levels in 839 physical examinees in Beijing]

Objective: To investigate the feasibility of application of non-fasting dyslipidemia cutoff values in community population. Methods: Self-control study was used. 839 physical examinees (292 males and 547 females) were recruited in clinical laboratory of Guang'an men Hospital from January to October 2018. The median (interquartile range) of age was 60 (54, 66) years. Blood samples were collected before and at 4 h after a standard breakfast. Comparison of fasting and postprandial lipoprotein levels was performed using Paired-Samples T Test or Two-Related-Samples Wilcoxon. The changes of 4-hour postprandial blood lipid levels and the percentages of postprandial dyslipidemia according to different stratification of fasting dyslipidemia were performed using one-way ANOVA and χ² test, respectively. Results: Compared with fasting, 4-hour postprandial total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), non-high density lipoprotein cholesterol (non-HDL-C), apolipoprotein A1 (ApoA1) and apolipoprotein B (ApoB) decreased slightly, postprandial triglyceride (TG) increased by 0.72 mmol/L, and postprandial remnant-like lipoprotein cholesterol (RLP-C) increased by 0.27 mmol/L (t or Z values = 10.26,22.94,24.22,4.71,16.61,26.92,-23.58,-19.35, P<0.05, respectively). According to the non-fasting dyslipidemia cut-off values recommended by the European consensus, there were 10%, 16.6%, 10.1%, 12.3%, 30% and 34.9% of the population in the appropriate levels of fasting TC, LDL-C, HDL-C, non-HDL-C, TG and RLP-C distributed in elevated levels of postprandial, respectively. The changes of 4-hour postprandial TC, LDL-C, non-HDL-C and HDL-C increased with the elevation of fasting level (F=9.50,6.18,8.07,3.86,P<0.01), and the maximum changes of TC≤3.5%, LDL-C≤6.8%, non-HDL-C≤2.9%, HDL-C≤6.3%; the change of 4-hour postprandial TG increased slightly first and then decreased significantly (51.3% vs. 57.9% vs. 39.2%, F=19.05, P<0.01); the change of 4-hour postprandial RLP-C decreased (50.8% vs. 33.2%, F=10.40, P<0.01). The cut-off values of 4-hour postprandial dyslipidemia were TC ≥5.1 mmol/L, LDL-C ≥3.2 mmol/L, HDL-C ≤0.9 mmol/L, non-HDL-C ≥4.0 mmol/L and RLP-C ≥1.0 mmol/L. The cut-off values of borderline elevated and elevated TG levels were ≥2.2 mmol/L and ≥3.4 mmol/L, respectively. Conclusions: The cut-off values of postprandial dyslipidemia including TC, LDL-C, HDL-C, non-HDL-C and RLP-C were preliminarily established in community population, which could be applied to the routine lipid profile evaluation in the physical examination population. And it might be needed that postprandial TG was managed hierarchically according to different cut-off values.

[Inhibitory effect of DAPT on Notch signaling pathway in curcumin mediated photodynamic therapy for cervical cancer xenografts in nude mice]

Objective: Curcumin was used as photosensitizers in photodynamic therapy on cervical cancer xenografts in nude mice.Analysis the expression changes of Notch and downstream gene as NF-κB and VEGF before and after DAPT inhibition of Notch signaling pathway in vivo experiments.Our aim was to investigate the possible mechanism of Notch signaling pathway in the treatment of cervical cancer with PDT. Methods: A cervical cancer model of nude mice was established by subcutaneous inoculation of human cervical cancer Me180 cells 200 μl.After the success of the model, the experimental animals were divided into 4 groups (model group, curcumin PDT group, simple DAPT group, curcumin-PDT+ DAPT group), each group was 12.Tumor volume changes were analyzed and HE staining was observed in each group.MRNA and protein expression of Notch1 and its downstream NF-κB, VEGF were detected by RT-PCR, immunohistochemistry and Western blot before and after inhibition of Notch signaling pathway by DAPT. Results: Except the control group, the tumor volume of the other three groups remained unchanged or slightly reduced after 1-7 days of treatment.The difference was significant (P<0.05). HE staining showed the most obvious necrosis of curcumin-PDT group with DAPT.Both DAPT and curcumin-PDT could reduce the expression level of Notch1 in mRNA.The inhibition rates were 42.17% and 40.54%, respectively.And the inhibitory effect of curcumin-PDT with DAPT on Notch-1 was the strongest (79.22%) (P<0.01), and two of them had synergistic effect after combination with curcumin-PDT.But the expression of Notch-2 has no obvious inhibitory effect (P>0.05). Both DAPT and curcumin-PDT can inhibit the protein expression of Notch1, NF-κB and VEGF, and two of them have synergistic effect after combined use. Conclusions: DAPT can effectively block the Notch signaling pathway and inhibit the proliferation of cervical cancer cell line Me180.The application of DAPT to inhibit Notch signaling pathway after photodynamic therapy can achieve synergistic effect, which is mainly related to the down-regulation of the expression of Notch1 and NF-κB.Notch signaling pathway may be one of the targets of curcumin-PDT photodynamic therapy.

Isolation and characterization of Streptomyces spp. strains F-6 and F-7 capable of decomposing alkali lignin

Biodegradation and bioconversion of lignin are the result of the combined action of fungi, bacteria and actinomycetes. Through screening from forest soil, two novel isolated actinomycete strains were identified as Streptomyces spp. strains F-6 and F-7 by their morphology, cultural characteristics and high homology to the 16S rRNA gene. Both strains possessed laccase and manganese peroxidase activities. Laccase activity produced by strain F-6 was up to 935.4 U g(-1) dry cell weight. More than 50% of alkali lignin was removed by strains F-6 and F-7 in 12 days of incubation. GC-MS analysis of the biodegraded products showed strain F-6 converted lignin into phenol and broken phenol compounds. The two strains could co-culture with white-rot fungus, and the combined actinonycete-fungus system decomposed alkali lignin effectively.

A comparison of slaughter performance and meat quality of pigs immunised with a gonadotrophin-releasing factor vaccine against boar taint with physically castrated pigs

The objective of this study was to evaluate the effect of vaccination against gonadotropin-releasing factor (GnRF) on carcass characteristics and meat quality and back fat quality. In total, 400 healthy male pigs were randomly assigned into two treatment groups: physically castrated males (CM) and vaccinated males (IM). CM pigs were physically castrated within 3 days of age. IM pigs received the GnRF vaccine twice, at 14 and 21 weeks of age. At the end of the experiment, 20 pigs of each treatment were weighed individually and slaughtered at 25 weeks of age. The longissimus muscle was collected to evaluate the meat quality including pH, drip loss, shear force, cooking loss, intramuscular fat, fatty acid composition and inosine monophosphate. Subcutaneous fat was sampled to evaluate fatty acid composition. IM pigs had a lower dressing percentage and were leaner (P < 0.01). The inosine monophosphate content was higher in pork from IM pigs than from CM pigs (P < 0.05). IM pigs had a higher content of polyunsaturated fatty acids in longissimus muscles than CM pigs (P < 0.01), mostly because of the higher linoleic acid content (P < 0.01). IM pigs had higher levels of unsaturated fatty acids in subcutaneous fat than CM pigs (P < 0.01), mostly because of the higher linoleic acid and linolenic acid (P < 0.01) and the lower myristic acid content (P < 0.01). There were no adverse effects of the GnRF vaccine on slaughter performance and meat quality of pigs. These results suggest that GnRF vaccine administered to pigs increases the inosine monophosphate content in longissimus muscles and the content of polyunsaturated fatty acids in longissimus muscles and back fat. Consequently, vaccination with Improvac for boar taint control will provide a good alternative to physical castration of male pigs.

Grafting sulfobetaine monomer onto the segmented poly(ether-urethane) surface to improve hemocompatibility

Polyurethanes are widely used as blood-contacting biomaterials, due to their good biocompatibility and mechanical properties. Nevertheless, their blood compatibility is still not adequate for more demanding applications. Surface modification is an effective way to improve the hemocompatibility for biomaterials. The purpose of the present study was to synthesize a novel nonthrombogenic biomaterial by modifying the surface of polyurethane. Ozonization was used to introduce active peroxide groups onto the segmented poly(ether-urethane) (SPEU) film surface and graft polymerization of N,N'-dimethyl (methacryloyloxyethyl) ammonium propanesulfonate (DMAPS), a sulfobetaine structure, onto the ozone-activated SPEU surface was conducted. The SPEU-g-PDMAPS film was characterized by ATR-FTIR, XPS, and contact angle measurements. ATR-FTIR and XPS confirmed the graft polymerization. The grafted film possessed a relatively hydrophilic surface, as revealed by contact angle measurement. The blood compatibility of the grafted films was evaluated by a platelet-rich plasma (PRP) adhesion study and scanning electron microscopy, using SPEU film as the reference. No platelet adhesion was observed for the grafted films incubated with PRP at 37 degrees C for 60 and 180 min. This new sulfobetaine structure grafted biomaterial might have potential for biomedical applications.

Platelet adhesion onto segmented polyurethane surfaces modified by carboxybetaine

Polyurethanes are widely used as blood-contacting biomaterials due to their good biocompatibility and mechanical properties. Nevertheless, their blood compatibility is still not adequate for more demanding applications. Surface modification is an effective way to improve the hemocompatibility for biomaterials. The purpose of present study was to synthesize a novel nonthrombogenic biomaterial by modifying the surface of polyurethane with Zwitterions of carboxybetaine monomer. The films of polyurethane were grafted with two kinds of carboxybetaine by a three-step procedure. In the first step, the film surfaces were treated with hexamethylene diisocyanate (HDI) in toluene at 50 degrees C in the presence of di-n-butyl tin dilaurate (DBTDL) as a catalyst. The extent of the reaction was measured by ATR-FT-IR spectra: a maximum number of free NCO group was obtained after a reaction time of 90 min. In the second step, the hydroxyl group of N,N-dimethylethylethanolamine (DMEA) or 4-dimethylamino-1-butanol (DMBA) was allowed to react in toluene with isocyanate groups bound on surface. In the third step, carboxybetaines were formed in the surface through the ring-opening reaction between tertiary amine of DMEA or DMBA and beta-propiolactone (PL). It was characterized by ATR-FT-IR and XPS that the grafted surfaces were composed of carboxybetaine. The results of the contact angle measurements showed that they were strongly hydrophilic. Platelet adhesion tests showed that films grafted carboxybetaine have good blood compatibility, as featured by the low platelet adhesion.

[Molecular tagging and mapping of QTLs for super quality fiber properties in upland cotton]

A G. anomalum introgression line, 7235, characterized as super quality fiber properties, was used to identify molecular markers linked to fiber property QTLs. By use of (7235 x TM-1)F2 in Nanjing and College Station, USA, and (7235 x TM-1)F3 in Nanjing and Hainan. Bulked segregation analysis was employed to produce 3 pairs of mixed DNA pools for fiber strength, micronaire and fiber length according to individual value of (7235 x TM-1)F2 and F2:3. A total of 221 pairs of SSR primers, 1,840 arbitrary 10-mer oligonucleotide primers and 77 ISSR primers were used to screen polymorphism between two parents, and 3 pairs of bulked DNA pools. Fifteen markers amplified by thirteen primers were identified to be linked with fiber quality QTLs through DNA polymorphism surveying between the parents, and then paired bulked DNAs, and screening the individual plant of (7235 x TM1)F2. Linkage test indicated 15 markers could be mapped to three linkage groups. In the first linkage group, eight markers (two SSR and six RAPD markers) associated with fiber strength were tightly linked with 2.2 cM interval genetic distance on average, and located on chromosome 10 in cotton. Two major QTLs for fiber quality characters were identified. One for fiber strength could explain 35% of the phenotypic variation in F2, and 53.8% in F2:3 at Hainan, which has the greatest single QTL effect of fiber strength and could be identified in all four environments, and tightly linked to 6 RAPD markers and 2 SSR markers with genetic distance no more than 16 cM in chromosome 10, in which FSRl933 is the nearest with the distance no more than 0.6 cM. One QTL linked to FMR1(603) for Micronaire could explain 7.8% of the phenotypic variation in F2, and 25.4% in F2:3 at Hainan, and expressed in all four environments. One QTL linked to FLR1(1550) for fiber length could explain 9.5% of the phenotypic variation in F2:3 at Hainan, very little in other environments. So they can be used in marker-assisted selection in increasing fiber quality of commercial cultivars.

Studies of the inheritance of seed qualities and the exploitation of F2 heterosis in low gossypol strains in upland cotton

Twenty cross combinations were made with 4 recessive glandless lines (gl2gl2 gl3gl3) used as females and 5 dominant glandless lines (Gl2eGl2e Gl3Gl3) used as male parents to estimate the genetic variance components of kernel oil and protein content of seeds, oil and protein index, and kernel index using a genetic model for parents, F2 and F3. The results showed that all the analyzed traits were mainly controlled by additive effects. Oil content was controlled mainly by maternal additive effect, and other traits by direct additive effect. The average heterosis of F2 over mid-parent based on population mean was -1.99% to 1.11% for all these traits. It suggests that little inbreeding depression exists for F2 and F3 seeds. There were 75% and 60% of the F2 and the F3 combinations in which open-pollinated seeds contained gossypol levels lower than 0.4 gkg-1. This result indicated that it is possible to screen and select high yielding F2 hybrids with a gossypol content lower than the regulated criterion and without lowering seed quality.

Plk is an M-phase-specific protein kinase and interacts with a kinesin-like protein, CHO1/MKLP-1

PLK (STPK13) encodes a murine protein kinase closely related to those encoded by the Drosophila melanogaster polo gene and the Saccharomyces cerevisiae CDC5 gene, which are required for normal mitotic and meiotic divisions. Affinity-purified antibody generated against the C-terminal 13 amino acids of Plk specifically recognizes a single polypeptide of 66 kDa in MELC, NIH 3T3, and HeLa cellular extracts. The expression levels of both poly(A)+ PLK mRNA and its encoded protein are most abundant about 17 h after serum stimulation of NIH 3T3 cells. Plk protein begins to accumulate at the S/G2 boundary and reaches the maximum level at the G2/M boundary in continuously cycling cells. Concurrent with cyclin B-associated cdc2 kinase activity, Plk kinase activity sharply peaks at the onset of mitosis. Plk enzymatic activity gradually decreases as M phase proceeds but persists longer than cyclin B-associated cdc2 kinase activity. Plk is localized to the area surrounding the chromosomes in prometaphase, appears condensed as several discrete bands along the spindle axis at the interzone in anaphase, and finally concentrates at the midbody during telophase and cytokinesis. Plk and CHO1/mitotic kinesin-like protein 1 (MKLP-1), which induces microtubule bundling and antiparallel movement in vitro, are colocalized during late M phase. In addition, CHO1/MKLP-1 appears to interact with Plk in vivo and to be phosphorylated by Plk-associated kinase activity in vitro.

[Follow-up result of 14 cases of the first metatarsophalangeal joint arthroplasty with titanium total joint prostheses]

An 8-year follow-up study of 14 cases (22 feet) of titanium total 1st metatarsophalangeal joint arthroplasty with two designs (type I and type II) is reported. The follow-up period average was 5 years with a range of 3 to 8 years. The rate of subjective satisfaction was 72.7% (16/22), the incidence of complications 31.8% (7/22), and the rate of revision 27.3% (6/22). The results implicate that titanium total hallux MTP joint arthroplasty is a suitable procedure for osteoarthritis, rheumatoid arthritis and hallux rigidus of the 1st MTP joint, and that type II prosthesis seems better than type I prosthesis. In addition, prosthetic designing, surgical technique and postoperative complications are also discussed in detail.

Properties of the DNA-binding domain of the Saccharomyces cerevisiae STE12 protein

The STE12 protein of the yeast Saccharomyces cerevisiae binds to the pheromone response element (PRE) present in the upstream region of genes whose transcription is induced by pheromone. Using DNase I footprinting assays with bacterially made STE12 fragments, we localized the DNA-binding domain to 164 amino acids near the amino terminus. Footprinting of oligonucleotide-derived sequences containing one PRE, or two PREs in head-to-tail or tail-to-tail orientation, showed that the N-terminal 215 amino acids of STE12 has similar binding affinity to either of the dimer sites and a binding affinity 5- to 10-fold lower for the monomer site. This binding cooperativity was also evident on a fragment from the MFA2 gene, which encodes the a-factor pheromone. On this fragment, the 215-amino-acid STE12 fragment protected both a consensus PRE as well as a degenerate PRE containing an additional residue. Mutation of the degenerate site led to a 5- to 10-fold decrease in binding; mutation of the consensus site led to a 25-fold decrease in binding. The ability of PREs to function as pheromone-inducible upstream activation sequences in yeast correlated with their ability to bind the STE12 domain in vitro. The sequence of the STE12 DNA-binding domain contains similarities to the homeodomain, although it is highly diverged from other known examples of this motif. Moreover, the alignment between STE12 and the homeodomain postulates loops after both the putative helix 1 and helix 2 of the STE12 sequence.

Pheromone-dependent phosphorylation of the yeast STE12 protein correlates with transcriptional activation

Haploid a and alpha cells of yeast respond to the pheromones alpha- and a-factor, respectively, by increasing the transcription of many genes whose products are essential for mating. The STE12 protein acts in this process by binding to the DNA sequence that mediates the increased transcription of pheromone-responsive genes. We show here that a hybrid protein containing STE12 fused to the DNA-binding domain of GAL4 can activate transcription of a reporter gene containing GAL4-binding sites but only after treatment of cells with pheromone. Thus, STE12 alone, when bound to DNA, is sufficient to mediate pheromone-induced transcription. By constructing hybrids of different STE12 regions with the GAL4 domain, we map the domain of STE12 necessary for this activation to the central third of the protein. Upon alpha-factor treatment, the hybrid of GAL4 with the complete STE12 sequence is rapidly phosphorylated, with kinetics consistent with the observed transcriptional induction of pheromone-responsive genes. The domain of STE12 necessary for this phosphorylation correlates with that involved in transcriptional activation. We propose that induction of pheromone-responsive genes is mediated by phosphorylation of STE12 to alter its activation function but not its DNA-binding ability.