Biodegradation of polyethylene terephthalate by Tenebrio molitor: Insights for polymer chain size, gut metabolome and host genes.

Polyethylene terephthalate (PET or polyester) is a commonly used plastic and also contributes to the majority of plastic wastes. Mealworms (Tenebrio molitor larvae) are capable of biodegrading major plastic polymers but their degrading ability for PET has not been characterized based on polymer chain size molecular size, gut microbiome, metabolome and transcriptome. We verified biodegradation of commercial PET by T. molitor larvae in a previous report. Here, we reported that biodegradation of commercial PET (Mw 29.43 kDa) was further confirmed by using the δ13C signature as an indication of bioreaction, which was increased from - 27.50‰ to - 26.05‰. Under antibiotic suppression of gut microbes, the PET was still depolymerized, indicating that the host digestive enzymes could degrade PET independently. Biodegradation of high purity PET with low, medium, and high molecular weights (MW), i.e., Mw values of 1.10, 27.10, and 63.50 kDa with crystallinity 53.66%, 33.43%, and 4.25%, respectively, showed a mass reduction of > 95%, 86%, and 74% via broad depolymerization. Microbiome analyses indicated that PET diets shifted gut microbiota to three distinct structures, depending on the low, medium, and high MW. Metagenome sequencing, transcriptomic, and metabolic analyses indicated symbiotic biodegradation of PET by the host and gut microbiota. After PET was fed, the host's genes encoding degradation enzymes were upregulated, including genes encoding oxidizing, hydrolyzing, and non-specific CYP450 enzymes. Gut bacterial genes for biodegrading intermediates and nitrogen fixation also upregulated. The multiple-functional metabolic pathways for PET biodegradation ensured rapid biodegradation resulting in a half-life of PET less than 4 h with less negative impact by PET MW and crystallinity.

Unveiling Fragmentation of Plastic Particles during Biodegradation of Polystyrene and Polyethylene Foams in Mealworms: Highly Sensitive Detection and Digestive Modeling Prediction.

It remains unknown whether plastic-biodegrading macroinvertebrates generate microplastics (MPs) and nanoplastics (NPs) during the biodegradation of plastics. In this study, we utilized highly sensitive particle analyzers and pyrolyzer-gas chromatography mass spectrometry (Py-GCMS) to investigate the possibility of generating MPs and NPs in frass during the biodegradation of polystyrene (PS) and low-density polyethylene (LDPE) foams by mealworms (Tenebrio molitor larvae). We also developed a digestive biofragmentation model to predict and unveil the fragmentation process of ingested plastics. The mealworms removed 77.3% of ingested PS and 71.1% of ingested PE over a 6-week test period. Biodegradation of both polymers was verified by the increase in the δ13C signature of residual plastics, changes in molecular weights, and the formation of new oxidative functional groups. MPs accumulated in the frass due to biofragmentation, with residual PS and PE exhibiting the maximum percentage by number at 2.75 and 7.27 µm, respectively. Nevertheless, NPs were not detected using a laser light scattering sizer with a detection limit of 10 nm and Py-GCMS analysis. The digestive biofragmentation model predicted that the ingested PS and PE were progressively size-reduced and rapidly biodegraded, indicating the shorter half-life the smaller plastic particles have. This study allayed concerns regarding the accumulation of NPs by plastic-degrading mealworms and provided critical insights into the factors controlling MP and NP generation during macroinvertebrate-mediated plastic biodegradation.

Biodegradation of polyvinyl chloride, polystyrene, and polylactic acid microplastics in Tenebrio molitor larvae: Physiological responses.

It is widely understood that microplastics (MPs) can induce various biological stresses in macroinvertebrates that are incapable of biodegrading plastics. However, the biodegradation and physiological responses of plastic-degrading macroinvertebrates toward MPs of different degradability levels remain unexplored. In this study, Tenebrio molitor larvae (mealworms) were selected as a model of plastics-degrading macroinvertebrate, and were tested against three common plastics of different degradability rankings: polyvinyl chloride (PVC), polystyrene (PS), and polylactic acid (PLA) MPs (size <300 µm). These three MPs were biodegraded with the rate sequence of PLA > PS > PVC, resulting in a reversed order of negative physiological responses (body weight loss, decreased survival, and biomass depletion) of mealworms. Simultaneously, the levels of reactive oxygen species (ROS), antioxidant enzyme activities, and lipid peroxidation were uniformly increased as polymer degradability decreased and intermediate toxicity increased. PVC MPs exhibited higher toxicity than the other two polymers. The oxidative stresses were effectively alleviated by supplementing co-diet bran. The T. molitor larvae fed with PLA plus bran showed sustainable growth without an increase in oxidative stress. The results provide new insights into the biotoxicity of MPs on macroinvertebrates and offer comprehensive information on the physiological stress responses of plastic-degrading macroinvertebrates during the biodegradation of plastics with different degradability levels.

Unveiling the residual plastics and produced toxicity during biodegradation of polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC) microplastics by mealworms (Larvae of Tenebrio molitor).

Evidence for plastic degradation by mealworms has been reported. However, little is known about the residual plastics derived from incomplete digestion during mealworm-mediated plastic biodegradation. We herein reveal the residual plastic particles and toxicity produced during mealworm-mediated biodegradation of the three most common microplastics, i.e., polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC). All three microplastics are effectively depolymerized and biodegraded. We discover that the PVC-fed mealworms exhibit the lowest survival rate (81.3 ± 1.5%) and the highest body weight reduction (15.1 ± 1.1%) among the experimental groups by the end of the 24-day experiment. We also demonstrate that the residual PVC microplastic particles are more difficult to depurate and excrete for the mealworms compared to the residual PE and PS particles by using laser direct infrared spectrometry. The levels of oxidative stress responses, including reactive oxygen species, antioxidant enzyme activities, and lipid peroxidation, are also highest in the PVC-fed mealworms. Sub-micron microplastics and small microplastics are found in the frass of mealworms fed with PE, PS, and PVC, with the smallest particles detected at diameters of 5.0, 4.0, and 5.9 µm, respectively. Our findings provide insights into the residual microplastics and microplastic-induced stress responses in macroinvertebrates under micro(nano)plastics exposure.

Adsorption and desorption mechanisms of oxytetracycline on poly(butylene adipate-co-terephthalate) microplastics after degradation: The effects of biofilms, Cu(II), water pH, and dissolved organic matter.

As the application of biodegradable polymers has grown, so has the interest in exploring the environmental behaviors of biodegradable microplastics (MPs). In this study, we investigated the interaction of oxytetracycline (OTC) with poly(butylene adipate-co-terephthalate) (PBAT) MPs after biodegradation, and explored the effect of the coexisting Cu(II) on OTC adsorption and desorption processes. The maximum adsorption amounts of virgin PBAT, biofilm PBAT, and degraded PBAT reached 692.05 µg·g-1, 1396.21 µg·g-1, and 1869.93 µg·g-1, respectively, and the presence of Cu(II) increased the OTC adsorption capacities by 431.16 %, 165.99 %, and 132.94 %, respectively. The enhanced adsorption capacities were attributed to the formation of PBAT-Cu-OTC complexes. The remarkable desorption hysteresis of OTC was observed on the degraded PBAT but not on the biofilm PBAT when Cu(II) was present, due to the complexation between Cu(II) and biofilms. The effect of Cu(II) varied depending on the MP physiochemical properties (e.g., surface areas, zeta potentials, and functional groups) and the environmental factors (e.g., the solution pH and coexisting dissolved organic matter). Fourier transform infrared spectroscopy (FTIR) coupled with X-ray photoelectron spectroscopy (XPS) identified the Cu(II) bridging effect, and various interaction forces between PBAT and OTC, including hydrogen-bonding, π-π, cation-π, and electrostatic interactions.

Microalgal wastewater recycling: Suitability of harvesting methods and influence on growth mechanisms.

Wastewater recycling helps address the challenge of microalgae biomass commercialization by allowing for efficient resource recovery. In this study, three conventional harvesting methods, including centrifugation, microfiltration, and flocculation sedimentation, were investigated to explore the effects of harvesting methods on the characteristics of recycled wastewater and the growth of microalgae to select a suitable harvesting method for the microalgal wastewater recycling system. During the wastewater recycling process, the least amount of accumulated substances was exhibited in the wastewater recycled by microfiltration, followed by centrifugation, and the most by flocculation sedimentation. After 4 batches of cultivation, microalgal biomass harvested from centrifugation wastewater and microfiltration wastewater was 21.26 % and 13.54 % higher than that from flocculation wastewater, respectively. Lipids, carbohydrates and pigments were all increased by varying degrees. Additionally, flocculation sedimentation was not suitable for the microalgal wastewater recycling process since the low residual nutrients, high salinity, and excessive algal organic matter severely inhibited the growth of microalgae. Under the regulation of phytohormones, microalgae increased their energy reserves, enhanced photosynthesis, and improved their defense capability to resist the increasing abiotic stress. This study provides scientific support for the selection of suitable harvesting technology during the microalgal wastewater recycling process.

Influence of Polymer Size on Polystyrene Biodegradation in Mealworms (Tenebrio molitor): Responses of Depolymerization Pattern, Gut Microbiome, and Metabolome to Polymers with Low to Ultrahigh Molecular Weight.

Biodegradation of polystyrene (PS) in mealworms (Tenebrio molitor lavae) has been identified with commercial PS foams. However, there is currently limited understanding of the influence of molecular weight (MW) on insect-mediated plastic biodegradation and the corresponding responses of mealworms. In this study, we provided the results of PS biodegradation, gut microbiome, and metabolome by feeding mealworms with high-purity PS microplastics with a wide variety of MW. Over 24 days, mealworms (50 individuals) fed with 0.20 g of PS showed decreasing removal of 74.1 ± 1.7, 64.1 ± 1.6, 64.4 ± 4.0, 73.5 ± 0.9, 60.6 ± 2.6, and 39.7 ± 4.3% for PS polymers with respective weight-average molecular weights (Mw) of 6.70, 29.17, 88.63, 192.9, 612.2, and 1346 kDa. The mealworms degraded most PS polymers via broad depolymerization but ultrahigh-MW PS via limited-extent depolymerization. The gut microbiome was strongly associated with biodegradation, but that with low- and medium-MW PS was significantly distinct from that with ultrahigh-MW PS. Metabolomic analysis indicated that PS biodegradation reprogrammed the metabolome and caused intestinal dysbiosis depending on MW. Our findings demonstrate that mealworms alter their gut microbiome and intestinal metabolic pathways in response to in vivo biodegradation of PS polymers of various MWs.

Biodegradation of polylactic acid by yellow mealworms (larvae of Tenebrio molitor) via resource recovery: A sustainable approach for waste management.

Polylactic acid (PLA) is biodegraded rapidly under composting or thermophilic temperature but slowly under natural conditions with substantial microplastics generated. In this study, we examined the feasibility of PLA biodegradation and developed a novel approach for PLA waste management using yellow mealworms (Tenebrio molitor larvae) to achieve biodegradation and resource recovery simultaneously. Results confirmed PLA biodegradation in mealworms as sole PLA and PLA-bran mixtures (10%, 20%, 30% and 50% PLA, wt/wt). Feeding PLA-bran mixtures supported the larval development with higher survival rates and lower cannibal rates than feeding PLA only at ambient temperature. The PLA conversion efficiency was 90.9% with 100% PLA diet and was around 81.5-86.9% with PLA-bran mixtures. A peak insect biomass yield was achieved at a PLA ratio of 20%. PLA biodegradation was verified via detection of chemical and thermal modifications. Gut microbial community analysis indicated that intestinal communities shifted with PLA biodegradation, resulting in clusters with OTUs unique to the PLA diet. Based on these findings, we propose a circular approach for PLA waste management via resource recovery of used PLA as the feedstock for insect biomass production, management of mealworm excrement waste as fertilizer, and utilization of agricultural products for PLA production.

Biodegradation of Polyvinyl Chloride (PVC) in Tenebrio molitor (Coleoptera: Tenebrionidae) larvae.

Tenebrio molitor larvae (Coleoptera: Tenebrionidae) are capable of depolymerizing and biodegrading polystyrene and polyethylene. We tested for biodegradation of Polyvinyl Chloride (PVC) in T. molitor larvae using rigid PVC microplastic powders (MPs) (70-150 µm) with weight-, number-, and size-average molecular weights (Mw, Mn and Mz) of 143,800, 82,200 and 244,900 Da, respectively, as sole diet at 25 °C. The ingestion rate was 36.62 ± 6.79 mg MPs 100 larvae-1 d-1 during a 16-day period. The egested frass contained about 34.6% of residual PVC polymer, and chlorinated organic carbons. Gel permeation chromatography (GPC) analysis indicated a decrease in the Mw, Mn and Mz by 33.4%, 32.8%, and 36.4%, respectively, demonstrating broad depolymerization. Biodegradation and oxidation of the PVC MPs was supported by the formation of OC and OC functional groups using frontier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR), and by significant changes in the thermal characteristics using thermo-gravimetric analysis (TGA). Chloride released was counted as about 2.9% of the PVC ingested, indicating limited mineralization of the PVC MPs. T. molitor larvae survived with PVC as sole diet at up to 80% over 5 weeks but did not complete their life cycle with a low survival rate of 39% in three months. With PVC plus co-diet wheat bran (1:5, w/w), they completed growth and pupation as same as bran only in 91 days. Suppression of gut microbes with the antibiotic gentamicin severely inhibited PVC depolymerization, indicating that the PVC depolymerization/biodegradation was gut microbe-dependent. Significant population shifts and clustering in the gut microbiome and unique OTUs were observed after PVC MPs consumption. The results indicated that T. molitor larvae are capable of performing broad depolymerization/biodegradation but limited mineralization of PVC MPs.

Biodegradation of low-density polyethylene and polystyrene in superworms, larvae of Zophobas atratus (Coleoptera: Tenebrionidae): Broad and limited extent depolymerization.

Larvae of Zophobas atratus (synonym as Z. morio, or Z. rugipes Kirsch, Coleoptera: Tenebrionidae) are capable of eating foams of expanded polystyrene (EPS) and low-density polyethylene (LDPE), similar to larvae of Tenebrio molitor. We evaluated biodegradation of EPS and LDPE in the larvae from Guangzhou, China (strain G) and Marion, Illinois, U.S. (strain M) at 25 °C. Within 33 days, strain G larvae ingested respective LDPE and PS foams as their sole diet with respective consumption rates of 58.7 ± 1.8 mg and 61.5 ± 1.6 mg 100 larvae-1d-1. Meanwhile, strain M required co-diet (bran or cabbage) with respective consumption rates of 57.1 ± 2.5 mg and 30.3 ± 7.7 mg 100 larvae-1 d-1. Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and thermal gravimetric analyses indicated oxidation and biodegradation of LDPE and EPS in the two strains. Gel permeation chromatography analysis revealed that strain G performed broad depolymerization of EPS, i.e., both weight-average molecular weight (Mw) and number-average molecular weight (Mn) of residual polymers decreased, while strain M performed limited extent depolymerization, i.e., Mw and Mn increased. However, both strains performed limited extent depolymerization of LDPE. After feeding antibiotic gentamicin, gut microbes were suppressed, and Mw and Mn of residual LDPE and EPS in frass were basically unchanged, implying a dependence on gut microbes for depolymerization/biodegradation. Our discoveries indicate that gut microbe-dependent LDPE and EPS biodegradation is present within Z. atratus in Tenebrionidae, but that the limited extent depolymerization pattern resulted in undigested polymers with high molecular weights in egested frass.

Reaction Route Selection for Cellulose Hydrogenolysis into C2/C3 Glycols by ZnO-Modified Ni-W/ß-zeolite Catalysts.

A ß-zeolite-supported nickel and tungsten catalyst (Ni-W/ß) was employed to generate C2/C3 glycols (ethylene and propylene glycols) in a satisfactory yield from cellulose. After optimizing the acidity of the support, the Ni-W synergy and the co-catalyst, the yield of C2/C3 glycols reached 70.1% (C %), with propylene glycol accounting for 51.1% of the product. This performance was attributed to the effective control of the major reaction steps, namely, hydrolysis, isomerization, retro-aldol condensation and hydrogenation, by the tailored Ni-W-ZnO/ß catalyst. The characterization and reaction results indicated that the cellulose hydrolysis step was promoted by the appropriate acidic sites of the ß-zeolite, and the reaction routes to C2/C3 glycols were influenced by the mass loading of Ni-W through the synergy of nickel and tungsten oxide, in which Ni is effective in the hydrogenation while W facilitates bond cleavage via a retro-aldol condensation (C6 to C2/C3). Moreover, with the leaching of metal during four cycles of reuse, the catalytic performance was also influenced by the synergy of Ni and W. In addition, the isomerization of glucose to fructose was promoted by ZnO and afforded a high yield of propylene glycol.

Biodegradation of Polystyrene by Dark ( Tenebrio obscurus) and Yellow ( Tenebrio molitor) Mealworms (Coleoptera: Tenebrionidae).

Yellow mealworms (larvae of Tenebrio molitor, Coleoptera: Tenebrionidae) have been proven to be capable of biodegrading polystyrene (PS) products. Using four geographic sources, we found that dark mealworms (larvae of Tenebrio obscurus) ate PS as well. We subsequently tested T. obscurus from Shandong, China for PS degradation capability. Our results demonstrated the ability for PS degradation within the gut of T. obscurus at greater rates than T. molitor. With expanded PS foam as the sole diet, the specific PS consumption rates for T. obscurus and T. molitor at similar sizes (2.0 cm, 62-64 mg per larva) were 32.44 ± 0.51 and 24.30 ± 1.34 mg 100 larvae-1 d-1, respectively. After 31 days, the molecular weight ( Mn) of residual PS in frass (excrement) of T. obscurus decreased by 26.03%, remarkably higher than that of T. molitor (11.67%). Fourier transform infrared spectroscopy (FTIR) indicated formation of functional groups of intermediates and chemical modification. Thermo gravimetric analysis (TGA) suggested that T. obscurus larvae degraded PS effectively based on the proportion of PS residue. Co-fed corn flour to T. obscurus and wheat bran to T. molitor increased total PS consumption by 11.6% and 15.2%, respectively. Antibiotic gentamicin almost completely inhibited PS depolymerization. High-throughput sequencing revealed significant shifts in the gut microbial community in both Tenebrio species that were associated with the PS diet and PS biodegradation, with changes in three predominant families (Enterobacteriaceae, Spiroplasmataceae, and Enterococcaceae). The results indicate that PS biodegradability may be ubiquitous within the Tenebrio genus which could provide a bioresource for plastic waste biodegradation.

Ubiquity of polystyrene digestion and biodegradation within yellow mealworms, larvae of Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae).

Academics researchers and "citizen scientists" from 22 countries confirmed that yellow mealworms, the larvae of Tenebrio molitor Linnaeus, can survive by eating polystyrene (PS) foam. More detailed assessments of this capability for mealworms were carried out by12 sources: five from the USA, six from China, and one from Northern Ireland. All of these mealworms digested PS foam. PS mass decreased and depolymerization was observed, with appearance of lower molecular weight residuals and functional groups indicative of oxidative transformations in extracts from the frass (insect excrement). An addition of gentamycin (30 mg g-1), a bactericidal antibiotic, inhibited depolymerization, implicating the gut microbiome in the biodegradation process. Microbial community analyses demonstrated significant taxonomic shifts for mealworms fed diets of PS plus bran and PS alone. The results indicate that mealworms from diverse locations eat and metabolize PS and support the hypothesis that this capacity is independent of the geographic origin of the mealworms, and is likely ubiquitous to members of this species.

Evolution of influenza A(H3N2) virus hemagglutinin (HA1) gene in Shangluo, China, 2014-2015 / 中国人兽共患病学报

Comparative analysis of the variations in HA 1 gene of the influenza A (H3N2) virus and the vaccine recommended were conducted in Shangluo city of China,during the surveillance year of 2014-2015.In this study,we collected the samples of H3N2 subtype strain from the Shanglou City of China during the surveillance period of 2014-2015.The strain was cultured in MDCK cells,HA gene fragment was amplified by RT-PCR and the nucleotide sequence was determined.Sequence alignment was performed using the clustax2.1 software.The phylogenetic tree was constructed by Mega6.0 software and was analyzed by Neighboring-joining method.Results showed that the homology of isolated strain during 2014-2015 was 97.2 ％-99.9％ and homology with the recommended vaccine strain A/Texas/50/2012 was 97.3％-98.5％.The amino acid sequence of the HA 1 gene of the isolated strain was compared with that of the vaccine strain.The major antigenic determinants of the isolates in 2014,having mutations were section B,Y159F,S198P,while the major antigenic determinants of isolates in 2015,having amino acid mutations were A zone G142R,B region S159F,S198P.These results indicated that the key antigenic determinant of influenza H3N2 subtype strain in Shangluo City has changed in 2014-2015 and A/Texas/50/2012 vaccine component is no more effective.Hence,there is an urgent need to update the influenza H3N2 subtype vaccine components and in future we should be deeply concerned about the evolution ofinfluenza H3N2 gene trends.

Analysis the viral etiology of fever and respiratory tract infection syndrome in Shaanxi province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>Analysis the viral pathogenic spectrum for patients with fever and respiratory tract infection syndrome in Shaanxi province during 2010 and investigate the molecular epidemiology characteristics of respiratory syncytial virus.</p><p><b>METHODS</b>A total of 208 patients' pharyngeal swabs were collected based on surveillance definition from January 2010 to January 2011 and screened for sixteen human respiratory virus types/subtypes by Qiaxcel-based multiplex reverse transcription-PCR assay, including HRV,HCoV, Flu, HPIV, ADV, HRSV, HMPV and HBoV and investigate molecular epidemiology of HRSV by sequencing and phylogenetic analysis of the C-terminal second hypervariable region of the G gene.</p><p><b>RESULTS</b>109 out of 208 specimens (53%) were positive for one or more viruses. HRSV(42. 2%) was the dominant pathogen detected, followed by Flu(24. 5%), PIV(20%), HRV(13.6%) and ADV( 10.9%),there were also 8 strains of HCoV, 5 strains of HMPV and 3 strains of HBoV detected. The results showed that 22 specimens were positive for two or more viruses, PIV (14/22) was the most frequently detected viral agent among co-infection specimens, and the highest incidence of mixed infection is aged 15-39 years group (P < 0.05). The overall viral detection rate was no related to age. In addition to Flu, HMPV and PIV, other viruses (HRV, HBoV, HCoV, ADV, RSV) mainly infected 0 to 4 years old children. Among 46 HRSV positive specimens, 42 HRSV-A strains clustered into NA1 genotype and two HRSV-B strains clustered into two genotypes, BA9 and GB2.</p><p><b>CONCLUSION</b>HRSV is the dominate pathogen collected from patients with fever and respiratory tract infection syndrome in Shaanxi and HRSV A is the predominant subtype. For most viruses, infection was most prevalent among children aged <4 years. PIV was the most common pathogen in co-infection.</p>

Genetic characterization of human parainfluenza virus 3 circulating in Gansu and Shaanxi Provinces from 2009 to 2011 / 病毒学报

To investigate the genetic characterization of Human parainfluenza virus-3 (HPIV-3) circulating in Gansu and Shaanxi Provinces of China, 719 throat swabs were collected from pediatric patients with acute respiratory infections from 2009-2011. Multiplex RT-PCR was used to screen common respiratory viral pathogens. For HPIV-3-positive specimens, nested RT-PCR was used to amplify the HN gene of HPIV-3. The nucleotides of Hemagglutinin-neuraminidase(HN)gene of 13 HPIV-3 positive strains identified in Gansu and Shaanxi Provinces were successfully sequenced and compared with those downloaded from GenBank. The phylogenetic analysis based on the nucleotides sequence of HN gene showed that 13 HPIV-3 strains belonged to sub-cluster C3 with little sequence variation (overall nucleotide divergence of 0.2%-2.3% and amino acid divergence at 0-1.1%). Compared with the complete gene of HPIV-3 strains from U.S.A., Canada, and Australia, the biggest divergence of the nucleotide and amino acid lovels was 6.0% and 3.4%, respectively. The nucleotide divergence between shaanxi09-2 and shaanxi10-H0091 was 0.9%, while the nucleotide divergence between shaanxi10-H005 and gansull-62110372 was 0.5%, between shaanxi09-2 and BJ/291/09 was 0.6%. However, there was no amino acid divergence among them. It is likely that HPIV-3 virus had been transmitting in Gansu and Shaanxi Provinces for several years. Human parainfluenza virus-3 (HPIV-3) circulated in Gansu and Shaanxi Provinces from 2009 to 2011 belonged to sub-cluster C3.

Comparison of direct immune-fluorescent assay and real-time quantitative PCR in detecting the Hantavirus / 中华预防医学杂志

<p><b>OBJECTIVE</b>To compare the differences between the direct immuno-fluorescent assay (DFA) and real-time quantitative PCR in detecting the Hantavirus (HV) in rat lungs.</p><p><b>METHODS</b>From April to October in 2012, a total of 479 rats were caught by mouse-trap in residential or wild areas in Huxian, Jingyang, and Meixian of Shaanxi province, where haemorrhagic fever with renal syndrome (HFRS) was highly prevalent. The rats were dissected to take the two lungs, one was frozen and applied immuno-fluorescent assay to detect HV antigen while the other one was extracted its RNA and detected HV nucleic acid by real-time quantitative PCR. Then we compared the positive rate of the two methods.</p><p><b>RESULTS</b>Out of the 479 rats, 105 were caught from residential areas and the other 374 were caught from wild areas. Among the 105 rats caught from residential areas, no HV were detected out neither by DFA nor by real-time quantitative PCR. Among the 374 wild rats, 13.1% (49/374) were detected HV positive by DFA and 14.7% (55/374) were detected HV positive by real-time quantitative PCR. The difference showed no statistical significance (χ(2) = 0.402, P = 0.526). When detecting each lung sample, the HV positive rate was 10.2% (49/479) under the detection by DFA while the HV positive rate was 11.5% (55/479) under the detection by real-time quantitative PCR. The difference had no statistical significance (χ(2) = 1.286, P = 0.257) and the consistency coefficient was 68.2% under the paired chi-square test analysis, which showed high consistency (u = 11.759, P < 0.05). The sensitivity of real-time quantitative PCR to detect HV was 77.6% (38/49) comparing with DFA as standard, and the specificity was 96.1% (413/430). Out of the 9 suspected HV positive sample detected by DFA, 6 were confirmed positive by real-time quantitative PCR and 3 were denied.</p><p><b>CONCLUSION</b>Compared with the DFA, real-time quantitative PCR could also be used to detect the infection of HV in rats, and the result might be more stable.</p>

Long term epidemiological effects of vaccination on hemorrhagical fever with renal syndrome (HFRS) in Shaanxi provincial HFRS epidemic areas / 中华流行病学杂志

Objective To evaluate the protective rate and the variation of HFRS-IgG on hemorrhagical fever with renal syndrome (HFRS) vaccine.Methods Cluster,random sampling and cross-sectional study were used to assess the protective rate of HFRS vaccination.Level of HFRS-IgG was detected with ELISA in epidemic and non-epidemic areas of HFRS.Results Curve equation was obtained as Yprocective rate=(0.863+0.283/Xvaccination term) × 100％ by protective rate with vaccination term.Protective rates showed a reducing trend,90％ after 7-8 years of vaccination,88％ after 10 years,and 94％ on average.Absorbance (A) value of HFRS-IgG was 4 times higher in persons with vaccination than those without,in the epidemic area.Higher antibody level could be obtained after primary vaccination,but the level of antibody had a 50％ reduction after 5-10 years of vaccination,and a 60％ reduction after 10 years of vaccination.Conclusion HFRS antibody had a 50％ reduction after 5-10 years of vaccination.The protective rate of HFRS vaccination had a 90％ loss,after 7-8 years of vaccination.Booster dose was necessary after 7 years of vaccination.

Prokaryotic expression, purification and activity assay of recombinant vascular endothelial growth factor / 南方医科大学学报

<p><b>OBJECTIVE</b>To express human vascular endothelial growth factor (hVEGF(165)) in E. coli JM109 in the form of fusion protein by genetic engineering and test the biological activity and immunological competence of the expressed protein.</p><p><b>METHODS</b>hVEGF(165) gene was subcloned by PCR and inserted into pQE30 plasmid. hVEGF(165) fusion protein was expressed in E. coli JM109 and purified by Ni(2+)-NTA. The immunological competence of the expressed protein was tested by means of Western blotting and enzyme-linked immunosorbent assay (ELISA), and its biological activity was assayed by chicken chorioallantoic membrane (CAM) and Matrigel angiogenesis assay.</p><p><b>RESULTS</b>The recombinant hVEGF(165) fusion protein was successfully expressed in E. coli JM109 and its expression accounted for 30% of the total cellular protein. The purified protein presented a single band of 23 kD in SDS-PAGE. Western blotting, ELISA, CAM and matrigel angiogenesis assay showed excellent immunologic competence and biological activity of the recombinant protein.</p><p><b>CONCLUSION</b>Recombinant hVEGF(165) protein with excellent biological activity has been successfully expressed in E.coli JM109, which may facilitate future study in construction of prefabricated tissue-engineered bone graft.</p>