Current Progress, Challenges and Prospects in the Development of COVID-19 Vaccines

The COVID-19 pandemic has resulted in over 772 million confirmed cases, including nearly 7 million deaths, according to the World Health Organization (WHO). Leveraging rapid development, accelerated vaccine approval processes, and large-scale production of various COVID-19 vaccines using different technical platforms, the WHO declared an end to the global health emergency of COVID-19 on May 5, 2023. Current COVID-19 vaccines encompass inactivated, live attenuated, viral vector, protein subunit, nucleic acid (DNA and RNA), and virus-like particle (VLP) vaccines. However, the efficacy of these vaccines is diminishing due to the constant mutation of SARS-CoV-2 and the heightened immune evasion abilities of emerging variants. This review examines the impact of the COVID-19 pandemic, the biological characteristics of the virus, and its diverse variants. Moreover, the review underscores the effectiveness, advantages, and disadvantages of authorized COVID-19 vaccines. Additionally, it analyzes the challenges, strategies, and future prospects of developing a safe, broad-spectrum vaccine that confers sufficient and sustainable immune protection against new variants of SARS-CoV-2. These discussions not only offer insight for the development of next-generation COVID-19 vaccines but also summarize experiences for combating future emerging viruses.

Phosphoproteomic analysis reveals changes in A-Raf-related protein phosphorylation in response to Toxoplasma gondii infection in porcine macrophages

BACKGROUND

Toxoplasma gondii is an obligate intracellular protozoan parasite that causes severe threats to humans and livestock. Macrophages are the cell type preferentially infected by T. gondii in vivo. Protein phosphorylation is an important posttranslational modification involved in diverse cellular functions. A rapidly accelerated fibrosarcoma kinase (A-Raf) is a member of the Raf family of serine/threonine protein kinases that is necessary for MAPK activation. Our previous research found that knockout of A-Raf could reduce T. gondii-induced apoptosis in porcine alveolar macrophages (3D4/21 cells). However, limited information is available on protein phosphorylation variations and the role of A-Raf in macrophages infected with T. gondii.

METHODS

We used immobilized metal affinity chromatography (IMAC) in combination with liquid chromatography tandem mass spectrometry (LC-MS/MS) to profile changes in phosphorylation in T. gondii-infected 3D4/21 and 3D4/21-ΔAraf cells.

RESULTS

A total of 1647 differentially expressed phosphorylated proteins (DEPPs) with 3876 differentially phosphorylated sites (DPSs) were identified in T. gondii-infected 3D4/21 cells (p3T group) when compared with uninfected 3D4/21 cells (pho3 group), and 959 DEPPs with 1540 DPSs were identified in the p3T group compared with infected 3D4/21-ΔAraf cells (p3KT group). Venn analysis revealed 552 DPSs corresponding to 406 DEPPs with the same phosphorylated sites when comparing p3T/pho3 versus p3T/p3KT, which were identified as DPSs and DEPPs that were directly or indirectly related to A-Raf.

CONCLUSIONS

Our results revealed distinct responses of macrophages to T. gondii infection and the potential roles of A-Raf in fighting infection via phosphorylation of crucial proteins.

Efficacy of Nimotuzumab plus Concurrent Chemo-Radiotherapy for Unresectable Esophageal Cancer: A Real-World Study

PURPOSE/OBJECTIVE(S)

The esophageal cancer ranked 7th in the morbidity of malignant cancer and the 6th contributed to carcinoma deaths. Most patients are diagnosed of advanced stage at first visiting. The 5-year survival rate of unresectable esophageal cancer is about 20% after the standard treatment of concurrent chemo-radiotherapy. Nimotuzumab, a humanized anti-EGFR antibody, has shown good efficacy and low toxicity in epithelial tumors. This two-center, real-world study evaluated the efficacy and safety of nimotuzumab combined with concurrent chemoradiotherapy in unresectable esophageal squamous cell carcinoma (ESCC).

MATERIALS/METHODS

Totally 503 eligible unresectable ESCC patients from Jan 2014 to Dec 2020 were included. 1:2 nearest neighbor propensity score matching (PSM) was performed to match the Nimo group (nimotuzumab plus concurrent chemo-radiotherapy) and CRT group (concurrent chemo-radiotherapy), and the covariates included age, gender, tumor location, lesion length, TNM stage, clinical stage, and radiotherapy dose. The primary endpoint was overall survival (OS). The secondary endpoints were progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR).

RESULTS

A total of 61 patients were in Nimo group which received nimotuzumab (200 mg/w, 4-6 weeks) combined with concurrent chemo-radiotherapy (chemotherapy: S-1/FP/TP/DP for 2-4 cycles; radiotherapy: 2DRT,3D-CRT or IMRT, 50-70 Gy in 25-35 fractions) and 107 patients in CRT group only received concurrent chemo-radiotherapy. The baseline characteristics were well balanced between the two groups. The efficacy of Nimo group was better than that of CRT group. The ORR was 85.2% vs. 71.0%, (P=0.037), the DCR was 98.4% vs. 91.6%, (P>0.05). The median PFS was 28.07 months vs. 19.54 months, and the 1-, 3- and 5-year PFS rates were 78.2% vs. 72.9%, 37.5% vs. 28.3%, and 29.1% vs. 21.3%, respectively (HR: 0.6860, 95% CI: 0.4902-0.9600, P=0.034). The median OS was 34.93 months vs. 24.30 months and the 1-, 3- and 5-year OS rates were 88.5% vs. 81.3%, 46.8% vs. 35.2% and 37.4% vs. 28.0%, respectively (HR: 0.6701, 95% CI: 0.4792-0.9372, P=0.024). The adverse events including radiation esophagitis, radiation pneumonitis, bone marrow suppression, nausea, vomiting, and rash were no significantly different between the two groups (P>0.05).

CONCLUSION

Nimotuzumab combined with concurrent chemo-radiotherapy improved the ORR, and prolonged PFS and OS in unresectable ESCC patients with a good tolerance.

Different serotypes of Escherichia coli flagellin exert identical adjuvant effects

Bacterial flagellin is a potent powerful adjuvant, which exerts its adjuvant activity by activating the Toll-like receptor 5 (TLR5) signaling pathway to induce host pro-inflammatory responses. Flagellin of Salmonella typhimurium (S. typhimurium) has shown strong adjuvant effects for a variety of vaccine candidates, however, the adjuvanticity of different serotypes of Escherichia coli (E. coli) flagellin (FliC) is unclear. To explore the adjuvant activity of different serotypes of E. coli flagellin, FliCH1, FliCH7, and FliCH19 recombinant flagellins were prokaryotically-expressed and purified. The adjuvanticity of three recombinant flagellins was evaluated by analyzing their abilities to induce the IL-8 production in human colorectal adenocarcinoma (Caco-2) cells and the immune responses to co-administrated FaeG antigen in mice. Sequence analysis showed that the N-and C-terminal regions are highly conserved, whereas the central region is hypervariable. The TLR5 recognized site is identical among these three serotypes of flagellins. Coomassie blue staining SDS-PAGE showed the molecular mass of FliCH1, FliCH7, and FliCH19 recombinant flagellin are 66 kDa, 64 kDa, and 68 kDa, which can be recognized by anti-FliCH1, FliCH7, and FliCH19 serum, respectively. Moreover, the flagellin serotypes induced similar levels of IL-8 and TNF-α production in Caco-2 cells, anti-FaeG specific IgG antibodies in mice, and IL-4 production in mice spleen cells. Our results indicated that E. coli flagellins can be an adjuvant for vaccine candidates and that different serotypes of E. coli flagellins possess identical adjuvant effects.

Sef fimbria operon construction, expression, and function for direct rapid detection of Salmonella Enteritidis

Salmonella Enteritidis (SE) causes both horizontal and vertical transmission of diseases in poultry industry and is also one of the main causes of human food poisoning. Sequence analysis of the sef operon of poultry-derived Salmonella serotypes showed the presence of an entire sef operon in SE, whereas only sef pseudogenes were found in Salmonella Gallinarum and Salmonella Pullorum. Subsequently, the sef operon of SE was cloned into the pBR322 plasmid and expressed in a modified Escherichia coli strain SE5000. sef operon expression was demonstrated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, western blot, agglutination assay, and transmission electron microscopy. The results showed that SE5000+Sef, but not SE5000+pBR322, could specifically react with SE-positive chicken serum in an agglutination assay, which could be clearly visualized by the naked eye within less than 2 min. In contrast, SE5000+Sef could not be recognized in Salmonella Gallinarum- and Salmonella Pullorum-positive chicken sera. Next, taking advantage of the exclusive presence of an entire sef operon in SE, we set up an agglutination-based detection system to monitor the dynamics of Sef-targeted antibody from SE-infected chicks for 47 days. Using the proposed detection method, SE was readily detectable starting from 2 weeks post-infection. Finally, we compared the proposed SE5000+Sef-based detection system with commercially available agglutination antigen using the classical bacterial isolation and identification procedure as reference. The results showed that the SE5000+Sef system was more consistent with the results of bacterial isolation and identification with almost 100% accuracy. We established a simple, sensitive, and cheap agglutination method for rapid and specific detection of SE-infected chickens, which can facilitate epidemiological investigation and eradication of SE infections. KEY POINTS: • Only the Salmonella Enteritidis serotype expressed Sef fimbriae in chicken infected with SE. • A rapid, large-scale method of detection by the naked eye of detection of SE-infected chicken is presented.

Vaccines against gastroenteritis, current progress and challenges

Enteric viral and bacterial infections continue to be a leading cause of mortality and morbidity in young children in low-income and middle-income countries, the elderly, and immunocompromised individuals. Vaccines are considered an effective and practical preventive approach against the predominantly fecal-to-oral transmitted gastroenteritis particularly in the resource-limited countries or regions where implementation of sanitation systems and supply of safe drinking water are not quickly achievable. While vaccines are available for a few enteric pathogens including rotavirus and cholera, there are no vaccines licensed for many other enteric viral and bacterial pathogens. Challenges in enteric vaccine development include immunological heterogeneity among pathogen strains or isolates, a lack of animal challenge models to evaluate vaccine candidacy, undefined host immune correlates to protection, and a low protective efficacy among young children in endemic regions. In this article, we briefly updated the progress and challenges in vaccines and vaccine development for the leading enteric viral and bacterial pathogens including rotavirus, human calicivirus, Shigella, enterotoxigenic Escherichia coli (ETEC), cholera, nontyphoidal Salmonella, and Campylobacter, and introduced a novel epitope- and structure-based vaccinology platform known as MEFA (multiepitope fusion antigen) and the application of MEFA for developing broadly protective multivalent vaccines against heterogenous pathogens.

Use of Fimbrial Rod for F18ab Fimbriae+ STEC Colonization to Host Cells

Type 1 fimbriae are important virulence determinants of some Gram-negative pathogens, which promote bacterial colonization. The fimbrial rod is primarily composed of multiple copies of the major fimbrial subunit FimA. FimH adhesin, however, is present as a fibrillar tip structure that drive bacteria binding to host cellular mannose containing receptor. Here, we provide protocols to evaluate and compare the function of type 1 fimbrial subunits in F18ab fimbriae⁺ Shiga toxin-producing Escherichia coli (STEC). We found that both FimA and FimH are required for bacterial adhesion, invasion, and biofilm formation. Deleting fimA gene showed much more reduction in bacterial adhesion and invasion to porcine intestinal columnar epithelial cells IPEC-J2, than that of fimH mutant. Biofilm formation was significantly reduced in both mutants with an equal level. In addition, qPCR demonstrated that either fimA or fimH deletion down-regulated the bacterial flagella and F18 fimbriae genes expression, while up-regulated adhesin was involved in diffuse adherence-I (AIDA-I) gene expression, suggesting the co-regulation of cell surface-localized adhesins in F18ab fimbriae⁺ STEC.

A multivalent vaccine candidate targeting enterotoxigenic Escherichia coli fimbriae for broadly protecting against porcine post-weaning diarrhea

Fimbriae-mediated initial adherence is the initial and critical step required for enterotoxigenic Escherichia coli (ETEC) infection. Therefore, vaccine candidates have been developed that target these fimbriae and induce specific anti-fimbriae antibodies to block initial ETEC attachment. While this vaccine effectively protects against ETEC-associated post-weaning diarrhea (PWD), developing a broadly effective vaccine against initial ETEC attachment remains a challenging problem, owing to the immunological heterogeneity among these antigens. Here, we applied multi-epitope fusion antigen (MEFA) technology to construct a FaeG-FedF-FanC-FasA-Fim41a MEFA using the adhesive subunits of predominant fimbriae K88 and F18 as the backbone, which also integrated epitopes from adhesive subunits of the rare fimbriae K99, 987P, and F41; we then generated a MEFA computational model and tested the immunogenicity of this MEFA protein in immunized mice. We next evaluated the potential of the fimbriae-targeted MEFA as a vaccine candidate to effectively prevent PWD using in vitro assessment of its anti-fimbriae, antibody-directed inhibition of bacterial adherence. Computational modeling showed that all relevant epitopes were exposed on the MEFA surface and mice subcutaneously immunized with the MEFA protein developed IgG antibodies to all five fimbriae. Moreover, anti-fimbriae antibodies induced by the MEFA protein significantly inhibited the adhesion of K88+, F18+, K99+, 987P+, and F41+ ETEC strains to piglet small intestinal IPEC-1 and IPEC-J2 cell lines. Taken together, these results indicate that FaeG-FedF-FanC-FasA-Fim41a MEFA protein induced specific anti-fimbriae neutralizing antibodies against the five targeted fimbriae. Critically, these results show the potential of fimbriae-targeted MEFA and indicate their promise as a broad, effective vaccine against PWD.

Immunogenicity characterization of genetically fused or chemically conjugated heat-stable toxin toxoids of enterotoxigenic Escherichia coli in mice and pigs

Enterotoxigenic Escherichia coli (ETEC) producing type Ib heat-stable toxin (STa) are a main cause of children's diarrhea and travelers' diarrhea, thus STa needs to be targeted in ETEC vaccine development. However, because this 19-amino acid STa is poorly immunogenic, attempts to genetically fuse or chemically couple it to carrier proteins have been made to enhance STa immunogenicity. In this study, we selected one genetic fusion and one chemical conjugate to comparatively evaluate STa immunogenicity. The genetic fusion is 3xSTaN12S-mnLTR192G/L211A carrying three toxoid (STaN12S) genetically fused to a double mutant LT monomer (mnLTR192G/L211A); the chemical conjugate is BSA-STaA14T, which has toxoid STaA14T chemically coupled to bovine serum albumin (BSA). We immunized mice with the STa toxoid fusion and chemical conjugates, and examined antibody responses. Furthermore, we immunized pigs and evaluated derived antibodies for efficacy to passively provide protection against ETEC diarrhea using a piglet model. Data showed that mice subcutaneously immunized with BSA-STaA14T or 3xSTaN12S-mnLTR192G/L211A developed a strong anti-STa antibody, and the induced antibodies exhibited equivalent toxin-neutralizing activities. Pigs immunized with 3xSTaN12S-mnLTR192G/L211A or BSA-STaA14T developed similar levels of anti-STa antibodies; piglets with passively acquired antibodies induced by the genetic fusion appeared better protected against STa + ETEC. Results from the current study indicate that the fusion and conjugate approaches are viable options for facilitating STa immunogenicity and developing ETEC vaccines.

Review of Newly Identified Functions Associated With the Heat-Labile Toxin of Enterotoxigenic Escherichia coli

Heat-labile toxin (LT) is a well-characterized powerful enterotoxin produced by enterotoxigenic Escherichia coli (ETEC). This toxin is known to contribute to diarrhea in young children in developing countries, international travelers, as well as many different species of young animals. Interestingly, it has also been revealed that LT is involved in other activities in addition to its role in enterotoxicity. Recent studies have indicated that LT toxin enhances enteric pathogen adherence and subsequent intestinal colonization. LT has also been shown to act as a powerful adjuvant capable of upregulating vaccine antigenicity; it also serves as a protein or antigenic peptide display platform for new vaccine development, and can be used as a naturally derived cell targeting and protein delivery tool. This review summarizes the epidemiology, secretion, delivery, and mechanisms of action of LT, while also highlighting new functions revealed by recent studies.

[Comparison of gemstone spectral curve and CT value of gastric cancer with different pathological types and differentiation degrees]

Objective: To investigate the differences of gemstone spectral curve and CT value of gastric cancer with different pathological types and differentiation degrees. Methods: 91 cases of preoperative gemstone CT images with gastric cancer were collected, including 24 cases of mucinous carcinoma, 67 cases of non-mucinous carcinoma, 16 cases of signet ring cell carcinoma, 8 cases of mucinous adenocarcinoma, 32 cases of moderately differentiated adenocarcinoma and 35 cases of poorly differentiated adenocarcinoma. Gemstone CT spectral imaging was performed preoperatively, and the spectral curve of the lesion in venous phase was obtained by using GSI Viewer software, the slope of the curve was calculated, and 11 monoenergetic CT values of 40~140 keV (10 keV interval) were measured. The gemstone spectral curves and CT values of gastric cancer with different pathological types and differentiation degrees are compared. Results: The curve slopes of non-mucinous carcinoma, signet ring cell carcinoma and poorly differentiated adenocarcinoma were -1.92±0.53, -1.73±0.37 and -2.14±0.54, respectively. The absolute values were higher than those of mucinous carcinoma (-1.45±0.54), mucinous adenocarcinoma (-0.90±0.34) and moderately differentiated adenocarcinoma (-1.67±0.41), and the differences were all statistically significant (P<0.05). There were significant differences in monoenergetic CT values between mucinous and non-mucinous carcinomas at 40-140 keV (all P<0.05). The former was lower than the latter in different degrees, and the lower the energy, the greater the difference was. There were significant differences in monoenergetic CT values between signet ring cell carcinoma and mucinous adenocarcinoma at 40-100 keV (all P<0.05); monoenergetic CT values between poorly differentiated adenocarcinoma and moderately differentiated adenocarcinoma at 40-90 keV showed statistically significant differences (P<0.05). Conclusions: Gastric cancer with different pathological types and differentiation degrees have their characteristic spectral curves in venous phase, and the monoenergetic CT values are significantly different at low energy. The spectral curve of gemstone CT may be helpful to evaluate the pathological type and differentiation degree of gastric cancer before operation.

Antibodies induced by enterotoxigenic Escherichia coli (ETEC) adhesin major structural subunit and minor tip adhesin subunit equivalently inhibit bacteria adherence in vitro

Antibodies that block the adherence of enterotoxigenic Escherichia coli (ETEC) to host intestinal epithelial cells are protective. Multiepitope-fusion-antigens (MEFAs) carrying epitopes of ETEC adhesin major subunits or tip minor subunits induced antibodies against ETEC adherence. Adherence inhibition effectiveness of antibodies induced by major subunit epitopes versus minor tip subunit epitopes, however, has not been comparatively characterized. In this study, we immunized mice with a major subunit MEFA or a tip MEFA, evaluated MEFA anti-adhesin immunogenicity, and examined induced-antibodies against bacteria in vitro adherence or in vivo colonization in mice. Mice subcutaneously immunized with major subunit MEFA CFA/I/II/IV or tip MEFA showed no adverse effects and developed strong antigen-specific antibody responses. Data showed that antibodies derived from two MEFAs were equally effective against adherence of the bacteria expressing CS1, CS2, CS3, CS4/CS6, CS5/CS6, or CS6 adhesin in vitro. Subsequently, we immunized mice with CFA/I fimbriae, major subunit CfaB, or minor tip adhesin subunit CfaE. We found that antibodies induced by CFA/I, CfaB and CfaE equally inhibited in vitro adherence of ETEC strain H10407. Furthermore, we immunized mice with CFA/I fimbriae, CfaB, or CfaE, and then challenged the mice with H10407. Data showed that although not significantly, fewer H10407 bacteria colonized the immunized mice. These results suggest that ETEC adhesin major subunit and minor tip subunit should be equally effective in inducing neutralizing anti-adhesin antibodies, and that major subunit CFA/I/II/IV MEFA or tip MEFA, perhaps combined with toxoid fusion 3xSTaN12S-mnLTR192G/L211A, can be used for development of broadly protective vaccines against ETEC diarrhea.

LncRNA MALAT1 facilities high glucose induced endothelial to mesenchymal transition and fibrosis via targeting miR-145/ZEB2 axis

OBJECTIVE

Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus (DM), but the pathophysiology of DN is complex and not fully understood. Renal tubal epithelial-mesenchymal transition (EMT) has been shown to be the critical mechanism of glomerulosclerosis and tubulointerstitial fibrosis. However, the precise mechanisms underlying EMT are not clear. MALAT1 was found induced by hyperglycemia in kidney but whether MALAT1 is involved in renal tubal EMT remains unknown. The objective of our study is to explore the role of MALAT1 in hyperglycemia-induced EMT and fibrosis.

PATIENTS AND METHODS

We used db/db mouse and high glucose (HG)-stimulated HK-2 cells as in vivo and in vitro model of DN, respectively. qRT-PCR was used to measure levels of MALAT1 and miR-145. In addition, we validated interactions of MALAT1-miR-145 and miR-145-ZEB2 by dual luciferase reporter assays. Western blot was used to examine expressions of proteins involved in EMT and fibrosis.

RESULTS

MALAT1 was upregulated while miR-145 was downregulated in renal tissues of db/db mice. Consistently, hyperglycemia significantly increased the level of MALAT1 but decreased miR-145 expression in a time-dependent manner in HK-2 cells. Furthermore, miR-145 binds to both MALAT1 and ZEB2. Knockdown MALAT1 or ZEB2 inhibited HG-induced EMT and fibrosis, similar to miR-145 overexpression.

CONCLUSIONS

Our study is the first to show that MALAT1 and miR-145 regulate HG-induced EMT and fibrosis. Mechanistically, MALAT1 functions as a sponge RNA for miR-145 to derepress the expression of target gene ZEB2, thereby inducing EMT and fibrosis. These results provide a novel potential target for DN therapy in the future.

Targeting ideal oral vaccine vectors based on probiotics: a systematical view

Probiotics have great potential to be engineered into oral vaccine delivery systems, which can facilitate elicitation of mucosal immunity without latent risks of pathogenicity. Combined with the progressive understanding of probiotics and the mucosal immune system as well as the advanced biotechniques of genetic engineering, the development of promising oral vaccine vectors based on probiotics is available while complicated and demanding. Therefore, a systematical view on the design of practical probiotic vectors is necessary, which will help to logically analyze and resolve the problems that might be neglected during our exploration. Here, we attempt to systematically summarize several fundamental issues vital to the effectiveness of the vector of probiotics, including the stability of the engineered vectors, the optimization of antigen expression, the improvement of colonization, and the enhancement of immunoreactivity. We also compared the existent strategies and some developing ones, attempting to figure out an optimal strategy that might deserve to be referred in the future development of oral vaccine vectors based on probiotics.

[Related factors on secondary drug resistance in HIV infected persons receiving antiretroviral therapy in Shandong province: a case-control study]

Objective: To explore the causes of secondary drug resistance among HIV infected persons who were receiving antiretroviral therapy in Shandong province, and provide evidence for the improvement of antiretroviral therapy strategy. Methods: A case-control study was designed with 1∶2 matching on case and control groups. Household and face-to-face interview were conducted in October, 2015. All the study subjects were screened from both the drug resistant database of antiretroviral therapy of Shandong provincial laboratory and national comprehensive HIV/AIDS database in Shandong. The sample size was estimated as 330 cases including 110 drug resistant and 220 non-drug resistant cases. Subjects were people living with HIV/AIDS (PLWHA) aged 15 or older and received antiretroviral therapy for more than 6 months with records of virus load (VL). Subjects who presented VL above 1 000 copies/ml would receive drug resistance testing. Subjects who were confirmed resistant to with secondary drug, were selected as case group, the rest subjects with non-secondary drug resistance would form the control group. EpiData 3.1 software and SPSS 22.0 software were used to establish a database. Related influencing factors were analyzed with non- conditional stepwise logistic regression model. Results: A total of 288 cases were enrolled, including 103 in the case and 185 cases in the control groups, with average age as (37.62±1.06) years and (37.90±0.74) years old, respectively. Most of them were male, married/cohabitant, with education level of junior/senior high school or below and under Han nationality. Results from the multivariate logistic regression model showed that ORs (95%CI) of receiving antiretroviral therapy for 1-3 years, or more than 3 years were equal to 8.80 (3.69-21.00), 3.00 (1.20-7.53), compared with receiving antiretroviral therapy less than one year, respectively. OR (95%CI) of Among the PLWHA that with missing rate above 25.0% on medication, the OR appeared as 15.41(4.59-51.71), compared with not missing medication. OR (95%CI) among those who took the medicine themselves was 0.22 (0.07-0.74). Conclusions: Factors as duration of treatment, missing rate on medication and taking medicine by oneself were of influence on secondary drug resistance. Other factors as duration on antiretroviral therapy longer than 1 year, missing rate above 25.0% on medication, were related to the risk on secondary drug resistance. However, if the medicine was taken by oneself, it served as a protective factor for secondary drug resistance. It is necessary to strengthen the intervention and health education programs related to antiretroviral therapy.

Significance of Enterotoxigenic Escherichia coli (ETEC) Heat-Labile Toxin (LT) Enzymatic Subunit Epitopes in LT Enterotoxicity and Immunogenicity

Enterotoxigenic Escherichia coli (ETEC) strains producing heat-labile toxin (LT) and/or heat-stable toxin (STa) are a top cause of children's diarrhea and travelers' diarrhea. Holotoxin-structured GM1-binding LT is a strong immunogen and an effective adjuvant, and can serve a carrier or a platform for multivalent vaccine development. However, the significance of peptide domains or epitopes of LT particularly enzymatic LTA subunit in association with LT enterotoxicity and immunogenicity has not been characterized. In this study, we identified B-cell epitopes in silico from LTA subunit and examined epitopes for immunogenicity and association with LT enterotoxicity. Epitopes identified from LTA subunit were individually fused to a modified chicken ovalbumin carrier protein, and each epitope-ovalbumin fusion was used to immunize mice. Data showed all 11 LTA epitopes were immunogenic; epitope 7 (105SPHPYEQEVSA115) induced greater titers of anti-LT antibodies which neutralized LT enterotoxicity more effectively. To examine these epitopes for the significance in LT enterotoxicity, we constructed LT mutants by substituting each of 10 epitopes at the toxic A1 domain of LTA subunit with a foreign epitope and examined LT mutants for enterotoxicity and GM1-binding activity. Data showed that LT mutants exhibited no enterotoxicity but retained GM1-binding activity. The results from this study indicated that while not all immunodominant LTA epitopes were neutralizing, LT mutants with an individual epitope substituted lost enterotoxicity but retained GM1-binding activity. These results provided additional information to understand LT immunogenicity and enterotoxicity and suggested the potential application of LT platform for multivalent vaccines against ETEC diarrhea and other diseases.IMPORTANCE No vaccine is licensed for enterotoxigenic Escherichia coli (ETEC) strains, which remain a leading cause of diarrhea in children from developing countries and international travelers. GM1-binding heat-labile toxin (LT) which is a key virulence factor of ETEC diarrhea is a strong vaccine antigen and a self-adjuvant. LT can also serve a backbone or platform for MEFA (multiepitope fusion antigen), a newly developed structural vaccinology technology, to present heterogeneous epitopes (by replacing LT epitopes) and to mimic epitope antigenicity for development of broadly protective vaccines. Data from this study identified neutralizing LT epitopes and demonstrated that substitution of LT epitopes eliminated LT enterotoxicity without altering GM1-binding activity, suggesting LT is potentially a versatile MEFA platform to present heterogeneous epitopes for multivalent vaccines against ETEC and other pathogens.

Co-administered Tag-Less Toxoid Fusion 3xSTaN12S-mnLTR192G/L211A and CFA/I/II/IV MEFA (Multiepitope Fusion Antigen) Induce Neutralizing Antibodies to 7 Adhesins (CFA/I, CS1-CS6) and Both Enterotoxins (LT, STa) of Enterotoxigenic Escherichia coli (ETEC)

Enterotoxigenic Escherichia coli (ETEC) bacteria remain a leading cause of children's diarrhea and travelers' diarrhea. Vaccines that induce antibodies to block ETEC bacterial adherence and to neutralize toxin enterotoxicity can be effective against ETEC-associated diarrhea. Recent studies showed that 6xHis-tagged CFA/I/II/IV multiepitope fusion antigen (MEFA) induced broad-spectrum antibodies to inhibit adherence of the seven most important ETEC adhesins (CFA/I, CS1 to CS6) (Ruan et al., 2014a) and 6xHis-tagged toxoid fusion antigen 3xSTaN12S-mnLTR192G/L211A (previously named as 3xSTaN12S-dmLT) elicited antibodies to neutralize both heat-labile toxin (LT) and heat-stable toxin (STa) produced by ETEC strains (Ruan et al., 2014b). In this study, we constructed two new genes to express tag-less toxoid fusion 3xSTaN12S-mnLTR192G/L211A and tag-less CFA/I/II/IV MEFA and then examined immunogenicity of each tag-less protein in mouse immunization. We further combined two tag-less proteins and investigated antigen co-administration in mice. Data showed that mice immunized with tag-less 3xSTaN12S-mnLTR192G/L211A or tag-less CFA/I/II/IV MEFA developed antigen-specific IgG antibody responses, and mice co-administered with two tag-less proteins induced neutralizing antibodies against seven adhesins and both toxins. These results indicated tag-less toxoid fusion 3xSTaN12S-mnLTR192G/L211A and tag-less CFA/I/II/IV MEFA administered individually or combined induced neutralizing antitoxin and/or anti-adhesin antibodies, and suggested the potential application of two tag-less proteins for ETEC vaccine development.

Comparative Analysis of Diffusional Kurtosis Imaging, Diffusion Tensor Imaging, and Diffusion-Weighted Imaging in Grading and Assessing Cellular Proliferation of Meningiomas

BACKGROUND AND PURPOSE

An accurate evaluation of the World Health Organization grade and cellular proliferation is particularly important in meningiomas. Our aim was to prospectively evaluate and compare diffusional kurtosis imaging, DTI, and DWI metrics in determining the grade and cellular proliferation of meningiomas.

MATERIALS AND METHODS

Ninety-six consecutive patients with histopathologically confirmed meningiomas were included in this study. Mean kurtosis, radial kurtosis, axial kurtosis, fractional anisotropy, mean diffusivity, and ADC were semiautomatically obtained in the solid components of tumors. Each normalized diffusion value was compared between high-grade meningiomas and low-grade meningiomas using the Mann-Whitney U test. Receiver operating characteristic, multiple logistic regression, and Pearson correlation analysis were used for statistical evaluations.

RESULTS

Diffusional kurtosis imaging metrics (mean kurtosis, radial kurtosis, and axial kurtosis) were significantly higher in high-grade meningiomas than in low-grade meningiomas (P ≤ .001). Mean diffusivity and ADC were significantly lower in high-grade meningiomas than in low-grade meningiomas (P = .003 and .002). Mean kurtosis had significantly greater area the under curve values than mean diffusivity and fractional anisotropy in differentiating high-grade meningiomas from low-grade meningiomas (P = .038 and .002). Mean kurtosis was the only variable that could be used to independently differentiate high-grade meningiomas and low-grade meningiomas (P < .001). Significant correlations were found between the Ki-67 labeling index and kurtosis metrics (P < .001), as well as for mean diffusivity and ADC (P = .004, and .007).

CONCLUSIONS

Compared with other diffusion metrics, mean kurtosis may serve as an optimal parameter for evaluating and predicting the meningioma grade. Moreover, diffusion metrics may potentially reflect cellular proliferation.

[Herpes simplex virus-2 infection and related factors among female drug abusers in the women's compulsory drug rehabilitation center of Shandong province]

Objective: This study aimed to understand the herpes simplex virus-2 (HSV-2) infection and related factors among female drug abusers in the women's compulsory drug rehabilitation center of Shandong province and to provide reference for the prevention and control of HSV-2 in these settings. Methods: We screened all of 451 female drug abusers in the women's compulsory drug rehabilitation centers in of Shandong province and conducted a study using both questionnaire investigation and serological tests for HSV-2, HIV and syphilis. We also used EpiData 3.1 software to establish a database and SPSS 20.0 software to conduct the χ(2) test and multivariate logistic regression analysis. Results: A total of 451 female drug abusers were under study. We noticed that the rates for HSV-2 infection, HIV infection and syphilis infection appeared as 72.1% (325/451), 2.2% (10/451) and 33.5% (151/451) respectively. Results from univariate analysis showed that factors as: awareness on AIDS, having temporary sex partner after using the drug, having multiple sex partners after using the drug, providing commercial services or having temporary sex practice before being detained, with syphilis infection etc., were associated with HSV-2 infection. Data from the multivariate analysis showed that the OR (95%CI) value of HSV-2 infection was 2.90 (1.19-7.06) for those who providing commercial service, when comparing to those who did not. Compared to those who did not suffer from syphilis infection, the OR (95%CI) value of HSV-2 infection for those with syphilis infection was 2.75 (1.63-4.63). Conclusions: The rate of HSV-2 infection was high in the women's compulsory drug rehabilitation center of Shandong province. We should enhance measures and promote condom use to prevent from HSV-2 and other sexually transmitted diseases among them.

A new locus regulating MICALL2 expression was identified for association with executive inhibition in children with attention deficit hyperactivity disorder

Impaired executive inhibition is a core deficit of attention deficit hyperactivity disorder (ADHD), which is a common childhood-onset psychiatric disorder with high heritability. In this study, we performed a two-stage genome-wide association study of executive inhibition in ADHD in Han Chinese. We used the Stroop color-word interference test to evaluate executive inhibition. After quality control, 780 samples with phenotype and covariate data were included in the discovery stage, whereas 922 samples were included in the replication stage. We identified one new significant locus at 7p22.3 for the Stroop word interference time (rs11514810, P=3.42E-09 for discovery, P=0.01176 for replication and combined P=5.249E-09). Regulatory feature analysis and expression quantitative trait loci (eQTL) data showed that this locus contributes to MICALL2 expression in the human brain. Most genes in the network interacting with MICALL2 were associated with psychiatric disorders. Furthermore, hyperactive-impulsive-like behavior was induced by reducing the expression of the zebrafish gene that is homologous to MICALL2, which could be rescued by tomoxetine (atomoxetine), a clinical medication for ADHD. Our results suggested that MICALL2 is a new susceptibility gene for executive inhibition deficiency related to hyperactive-impulsive behavior in ADHD, further emphasizing the possible role of neurodevelopmental genes in the pathogenic mechanism of ADHD.

Pharmacogenomics study of thiazide diuretics and QT interval in multi-ethnic populations: the cohorts for heart and aging research in genomic epidemiology

Thiazide diuretics, commonly used antihypertensives, may cause QT interval (QT) prolongation, a risk factor for highly fatal and difficult to predict ventricular arrhythmias. We examined whether common single-nucleotide polymorphisms (SNPs) modified the association between thiazide use and QT or its component parts (QRS interval, JT interval) by performing ancestry-specific, trans-ethnic and cross-phenotype genome-wide analyses of European (66%), African American (15%) and Hispanic (19%) populations (N=78 199), leveraging longitudinal data, incorporating corrected standard errors to account for underestimation of interaction estimate variances and evaluating evidence for pathway enrichment. Although no loci achieved genome-wide significance (P<5 × 10-8), we found suggestive evidence (P<5 × 10-6) for SNPs modifying the thiazide-QT association at 22 loci, including ion transport loci (for example, NELL1, KCNQ3). The biologic plausibility of our suggestive results and simulations demonstrating modest power to detect interaction effects at genome-wide significant levels indicate that larger studies and innovative statistical methods are warranted in future efforts evaluating thiazide-SNP interactions.

Association between water fluoride and the level of children's intelligence: a dose-response meta-analysis

OBJECTIVES

Higher fluoride concentrations in water have inconsistently been associated with the levels of intelligence in children. The following study summarizes the available evidence regarding the strength of association between fluoridated water and children's intelligence.

STUDY DESIGN

Meta-analysis.

METHODS

PubMed, Embase, and Cochrane Library databases were systematically analyzed from November 2016. Observational studies that have reported on intelligence levels in relation to high and low water fluoride contents, with 95% confidence intervals (CIs) were included. Further, the results were pooled using inverse variance methods. The correlation between water fluoride concentration and intelligence level was assessed by a dose-response meta-analysis.

RESULTS

Twenty-six studies reporting data on 7258 children were included. The summary results indicated that high water fluoride exposure was associated with lower intelligence levels (standardized mean difference : -0.52; 95% CI: -0.62 to -0.42; P < 0.001). The findings from subgroup analyses were consistent with those from overall analysis. The dose-response meta-analysis suggested a significant association between water fluoride dosage and intelligence (P < 0.001), while increased water fluoride exposure was associated with reduced intelligence levels.

CONCLUSIONS

Greater exposure to high levels of fluoride in water was significantly associated with reduced levels of intelligence in children. Therefore, water quality and exposure to fluoride in water should be controlled in areas with high fluoride levels in water.

Genetic fusion protein 3×STa-ovalbumin is an effective coating antigen in ELISA to titrate anti-STa antibodies

Heat-stable toxin type I (STa)-ovalbumin chemical conjugates are currently used as the only coating antigen in ELISA to titrate anti-STa antibodies for ETEC vaccine candidates. STa-ovalbumin chemical conjugation requires STa toxin purification, a process that can be carried out by only a couple of laboratories and often with a low yield. Alternative ELISA coating antigens are needed for anti-STa antibody titration for ETEC vaccine development. In the present study, we genetically fused STa toxin gene (three copies) to a modified chicken ovalbumin gene for genetic fusion 3×STa-ovalbumin, and examined application of this fusion protein as an alternative coating antigen of anti-STa antibody titration ELISA. Data showed fusion protein 3×STa-ovalbumin was effectively expressed and extracted, and anti-STa antibody titration ELISA using this recombinant protein (25 ng per well) or STa-ovalbumin chemical conjugates (10 ng/well) showed the same levels of sensitivity and specificity. Furthermore, mice immunized with this fusion protein developed anti-STa antibodies; induced antibodies showed in vitro neutralization activity against STa toxin. These results indicate that recombinant fusion protein 3×STa-ovalbumin is an effective ELISA coating antigen for anti-STa antibody titration, enabling a reliable reagent supply to make standardization of STa antibody titration assay feasible and to accelerate ETEC vaccine development.

MEFA (multiepitope fusion antigen)-Novel Technology for Structural Vaccinology, Proof from Computational and Empirical Immunogenicity Characterization of an Enterotoxigenic Escherichia coli (ETEC) Adhesin MEFA

Vaccine development often encounters the challenge of virulence heterogeneity. Enterotoxigenic Escherichia coli (ETEC) bacteria producing immunologically heterogeneous virulence factors are a leading cause of children's diarrhea and travelers' diarrhea. Currently, we do not have licensed vaccines against ETEC bacteria. While conventional methods continue to make progress but encounter challenge, new computational and structure-based approaches are explored to accelerate ETEC vaccine development. In this study, we applied a structural vaccinology concept to construct a structure-based multiepitope fusion antigen (MEFA) to carry representing epitopes of the seven most important ETEC adhesins [CFA/I, CFA/II (CS1-CS3), CFA/IV (CS4-CS6)], simulated antigenic structure of the CFA/I/II/IV MEFA with computational atomistic modeling and simulation, characterized immunogenicity in mouse immunization, and examined the potential of structure-informed vaccine design for ETEC vaccine development. A tag-less recombinant MEFA protein (CFA/I/II/IV MEFA) was effectively expressed and extracted. Molecular dynamics simulations indicated that this MEFA immunogen maintained a stable secondary structure and presented epitopes on the protein surface. Empirical data showed that mice immunized with the tagless CFA/I/II/IV MEFA developed strong antigen-specific antibody responses, and mouse serum antibodies significantly inhibited in vitro adherence of bacteria expressing these seven adhesins. These results revealed congruence of antigen immunogenicity between computational simulation and empirical mouse immunization and indicated this tag-less CFA/I/II/IV MEFA potentially an antigen for a broadly protective ETEC vaccine, suggesting a potential application of MEFA-based structural vaccinology for vaccine design against ETEC and likely other pathogens.

Comparative efficacy and toxicity of induction chemotherapy with concurrent stereotactic body radiotherapy and stereotactic body radiotherapy with subsequent chemotherapy in patients with clinical stage T1-3N0M0 non-small cell lung carcinoma

PURPOSE

We compared the clinical efficacy and toxicity of stereotactic body radiotherapy with induction chemotherapy and concurrent radiochemotherapy vs stereotactic body radiotherapy with subsequent chemotherapy in patients with clinical stage T1-3N0M0 non-small cell lung carcinoma.

METHODS

We retrospectively analyzed 38 patients with c-stage T1-3N0M0 non-small cell lung carcinoma who received stereotactic body radiotherapy. All patients received six cycles of chemotherapy. Fifteen of the patients were treated with three cycles of induction chemotherapy, one cycle of concurrent radiochemotherapy, and then two cycles of consolidation chemotherapy, while 23 patients received Sequential Radiotherapy/Chemotherapy.

RESULTS

Patients in the induction chemotherapy group experienced a longer duration of esophagitis (median 2 vs 0, range 0-6 vs 0-3.6 weeks, p = 0.04). We divided the patients into two groups based on their median pre-treatment tumor volume (cm³): >32.11 and ≤32.11. The tumor response rate in patients with larger tumor volume was substantially higher in the induction chemotherapy group than in the Sequential Radiotherapy/Chemotherapy group (66.67 vs 40%). Among patients with pre-treatment tumor volume (cm³) >32.11, the median local progression-free survival (LPFS) in the induction chemotherapy group and Sequential Radiotherapy/Chemotherapy group was 18 months (range 7-72 months) and 11 months (range 6-53 months), respectively. There was a statistically significant difference between the two groups (p = 0.006).

CONCLUSIONS

Simultaneous SBRT and chemotherapy can result in a longer duration of esophagitis. However, for patients with large tumor volume, ICT combined with concurrent radiochemotherapy may result in better local tumor response as well as longer LPFS and progression-free survival. To better elucidate the best treatment, further clinical trials are needed.

Passive antibodies derived from intramuscularly immunized toxoid fusion 3xSTaN12S-dmLT protect against STa+ enterotoxigenic Escherichia coli (ETEC) diarrhea in a pig model

Enterotoxigenic Escherichia coli (ETEC) strains are among the most common causes of children's diarrhea and travelers' diarrhea. Developing effective vaccines against ETEC associated diarrhea becomes a top priority. ETEC heat-labile toxin (LT) and heat-stable toxin (STa) toxoid fusion 3xSTa_N12S-dmLT was demonstrated recently to induce neutralizing antitoxin antibodies in intraperitoneally or subcutaneously immunized mice. However, whether antibodies derived from this toxoid fusion are protective against ETEC diarrhea has not been examined. In this study, we intramuscularly immunized pregnant gilts with toxoid fusion 3xSTa_N12S-dmLT, challenged suckling piglets with a STa-positive ETEC strain, and assessed protective efficacy of passive acquire antitoxin antibodies against ETEC diarrhea. Data showed all three immunized gilts developed anti-STa IgG and IgA antibodies, and piglets born to the immunized dams acquired anti-STa and anti-LT antibodies. When challenged with a STa+ ETEC strain, none of the piglets born to the immunized dams developed watery diarrhea, with 20 piglets remained normal and the other 8 piglets developed mild diarrhea indicated with stained butt. In contrast, the control dams and born piglets had no anti-STa or anti-LT antibodies detected, and 26 out 32 piglets developed watery diarrhea after challenge of the STa+ ETEC strain. These results indicated that passive acquired anti-STa antibodies are protective against ETEC diarrhea, and suggested potential application of toxoid fusion 3xSTa_N12S-dmLT in ETEC vaccine development.

Enterotoxigenic Escherichia coli heat-stable toxin and heat-labile toxin toxoid fusion 3xSTaN12S-dmLT induces neutralizing anti-STa antibodies in subcutaneously immunized mice

Enterotoxigenic Escherichia coli (ETEC) bacteria producing heat-stable toxin (STa) and/or heat-labile toxin (LT) are among top causes of children's diarrhea and travelers' diarrhea. Currently no vaccines are available for ETEC associated diarrhea. A major challenge in developing ETEC vaccines is the inability to stimulate protective antibodies against the key STa toxin that is potently toxic and also poorly immunogenic. A recent study suggested toxoid fusion 3xSTaN12S-dmLT, which consists of a monomer LT toxoid (LTR192G/L211A) and three copies of STa toxoid STaN12S, may represent an optimal immunogen inducing neutralizing antibodies against STa toxin [IAI 2014, 82(5):1823-32]. In this study, we immunized mice with this fusion protein following a different parenteral route and using different adjuvants to further characterize immunogenicity of this toxoid fusion. Data from this study showed that 3xSTaN12S-dmLT toxoid fusion induced neutralizing anti-STa antibodies in the mice following subcutaneous immunization, as effectively as in the mice under intraperitoneal route. Data also indicated that double mutant LT (dmLT) can be an effective adjuvant for this toxoid fusion in mice subcutaneous immunization. Results from this study affirmed that toxoid fusion 3xSTaN12S-dmLT induces neutralizing antibodies against STa toxin, suggesting this toxoid fusion is potentially a promising immunogen for ETEC vaccine development.

Antibodies derived from an enterotoxigenic Escherichia coli (ETEC) adhesin tip MEFA (multiepitope fusion antigen) against adherence of nine ETEC adhesins: CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS21 and EtpA

Diarrhea continues to be a leading cause of death in children younger than 5 years in developing countries. Enterotoxigenic Escherichia coli (ETEC) is a leading bacterial cause of children's diarrhea and travelers' diarrhea. ETEC bacteria initiate diarrheal disease by attaching to host receptors at epithelial cells and colonizing in small intestine. Therefore, preventing ETEC attachment has been considered the first line of defense against ETEC diarrhea. However, developing vaccines effectively against ETEC bacterial attachment encounters challenge because ETEC strains produce over 23 immunologically heterogeneous adhesins. In this study, we applied MEFA (multiepitope fusion antigen) approach to integrate epitopes from adhesin tips or adhesive subunits of CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS21 and EtpA adhesins and to construct an adhesin tip MEFA peptide. We then examined immunogenicity of this tip MEFA in mouse immunization, and assessed potential application of this tip MEFA for ETEC vaccine development. Data showed that mice intraperitoneally immunized with this adhesin tip MEFA developed IgG antibody responses to all nine ETEC adhesins. Moreover, ETEC and E. coli bacteria expressing these nine adhesins, after incubation with serum of the immunized mice, exhibited significant reduction in attachment to Caco-2 cells. These results indicated that anti-adhesin antibodies induced by this adhesin tip MEFA blocked adherence of the most important ETEC adhesins, suggesting this multivalent tip MEFA may be useful for developing a broadly protective anti-adhesin vaccine against ETEC diarrhea.

RNA-Seq analysis for the potential targets and molecular mechanisms of 17 β-estradiol in squamous cell lung carcinoma

The efficacy of 17 β-estradiol (E2) was valid in some cancers, while its effects on squamous cell lung carcinoma (SCLC) were still unclear. The aim of our study was to investigate the potential targets and molecular mechanisms of E2 in SCLC cells.Two RNA libraries from human lung carcinoma cells (SK-MES-1) with and without E2 treatment were constructed and sequenced. The differentially expressed genes (DEGs) between cells with or without E2 treatment were identified by cuffdiff software. Hierarchical Clustering Analysis (HCA) was performed for displaying gene expression changes and classification. Furthermore, enrichment analyses of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology Biological Process (GO BP) terms were performed through DAVID. The protein-protein interaction (PPI) network was constructed through STRING. Additionally, differentially expressed lncRNAs were also selected by cuffdiff software.Total 129 DEGs including 58 up- and 71 down- regulated genes were obtained. Cancer-related pathways including small cell lung cancer, hypertrophic cardiomyopathy (HCM) and pathways in cancer and biological processes including regulation of phosphorus metabolic process, protein localization and nucleus organization were enriched. The PPI network with 113 nodes and 312 edges was constructed. CASP3, ITGA2, COL4A6, PML and CDC25B were identified as hub nodes which had more interactions with others in the PPI network. Furthermore, eight up-regulated and ten down-regulated lncRNAs were selected.CASP3, ITGA2 and Lnc-DLK1-4:31 (one of down-regulated lncRNAs) might play pivotal roles in E2 treated SCNC cells by influencing cell apoptosis, angiogenesis and cell invasion respectively.

Genetic parameters and genetic correlations among triacylglycerol and phospholipid fractions in Angus cattle

The objective of this study was to estimate genetic parameters for intramuscular fatty acids from triacylglycerol (TAG) and phospholipid (PL) fractions in beef LM tissue. Longissimus muscle samples were obtained from 1,833 Angus cattle to determine the intramuscular fatty acid composition for 31 lipids and lipid classes from TAG and PL fractions and were classified by structure into saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA), omega-3 (n-3), and omega-6 (n-6) fatty acids. An atherogenic index (AI) was also determined as a measure of the unsaturated fatty acid to SFA ratio. Restricted maximum likelihood methods combined with pedigree data were used to estimate variance components with the WOMBAT software package. Heritability estimates ranged from 0.00 to 0.63 for the major classes of fatty acids. Heritability estimates differed between the TAG and PL fractions, with higher estimates for TAG up to 0.64 and lower estimates for PL that ranged from 0.00 to 0.14. Phenotypic and genetic correlations among individual fatty acids were determined for the TAG fraction as well as among carcass traits, including rib eye area, numerical marbling score, yield grade, ether fat, and Warner-Bratzler shear force value. Strong negative or positive genetic correlations were observed among individual fatty acids in the TAG fraction, which ranged from -0.99 to 0.97 ( < 0.05). Moderate correlations between carcass traits and fatty acids from the TAG fraction ranged from -0.43 to 0.32 ( < 0.05). These results indicate that fatty acids prominent in beef tissues show significant genetic variation as well as genetic relationships with carcass traits.

Antibodies derived from a toxoid MEFA (multiepitope fusion antigen) show neutralizing activities against heat-labile toxin (LT), heat-stable toxins (STa, STb), and Shiga toxin 2e (Stx2e) of porcine enterotoxigenic Escherichia coli (ETEC)

Enterotoxigenic Escherichia coli (ETEC) strains are the main cause of diarrhea in pigs. Pig diarrhea especially post-weaning diarrhea remains one of the most important swine diseases. ETEC bacterial fimbriae including K88, F18, 987P, K99 and F41 promote bacterial attachment to intestinal epithelial cells and facilitate ETEC colonization in pig small intestine. ETEC enterotoxins including heat-labile toxin (LT) and heat-stable toxins type Ia (porcine-type STa) and type II (STb) stimulate fluid hyper-secretion, leading to watery diarrhea. Blocking bacteria colonization and/or neutralizing enterotoxicity of ETEC toxins are considered effective prevention against ETEC diarrhea. In this study, we applied the MEFA (multiepitope fusion antigen) strategy to create toxoid MEFAs that carried antigenic elements of ETEC toxins, and examined for broad antitoxin immunogenicity in a murine model. By embedding STa toxoid STa_P12F (NTFYCCELCCNFACAGCY), a STb epitope (KKDLCEHY), and an epitope of Stx2e A subunit (QSYVSSLN) into the A1 peptide of a monomeric LT toxoid (LT_R192G), two toxoid MEFAs, 'LT_R192G-STb-Stx2e-STa_P12F' and 'LT_R192G-STb-Stx2e-3xSTa_P12F' which carried three copies of STa_P12F, were constructed. Mice intraperitoneally immunized with each toxoid MEFA developed IgG antibodies to all four toxins. Induced antibodies showed in vitro neutralizing activities against LT, STa, STb and Stx2e toxins. Moreover, suckling piglets born by a gilt immunized with 'LT_R192G-STb-Stx2e-3xSTa_P12F' were protected when challenged with ETEC strains, whereas piglets born by a control gilt developed diarrhea. Results from this study showed that the toxoid MEFA induced broadly antitoxin antibodies, and suggested potential application of the toxoid MEFA for developing a broad-spectrum vaccine against ETEC diarrhea in pigs.

Membrane cholesterol plays an important role in enteropathogen adhesion and the activation of innate immunity via flagellin-TLR5 signaling

Lipid rafts are cholesterol- and sphingolipid-rich ordered microdomains distributed in the plasma membrane that participates in mammalian signal transduction pathways. To determine the role of lipid rafts in mediating interactions between enteropathogens and intestinal epithelial cells, membrane cholesterol was depleted from Caco-2 and IPEC-J2 cells using methyl-β-cyclodextrin. Cholesterol depletion significantly reduced Escherichia coli and Salmonella enteritidis adhesion and invasion into intestinal epithelial cells. Complementation with exogenous cholesterol restored bacterial adhesion to basal levels. We also evaluated the role of lipid rafts in the activation of Toll-like receptor 5 signaling by bacterial flagellin. Depleting membrane cholesterol reduced the ability of purified recombinant E. coli flagellin to activate TLR5 signaling in intestinal cells. These data suggest that both membrane cholesterol and lipid rafts play important roles in enteropathogen adhesion and contribute to the activation of innate immunity via flagellin-TLR5 signaling.

Sire breed effect on beef longissimus mineral concentrations and their relationships with carcass and palatability traits

The objective of this study was to evaluate sire breed effect on mineral concentration in beef longissimus thoracis (LT) and investigate the correlations between beef mineral concentrations and carcass and palatability traits. Steer progeny (N=246) from the Germplasm Evaluation project-Cycle VIII were used in this study. In addition to carcass traits, LT was evaluated for mineral concentrations, Warner-Bratzler shear force, and palatability traits. A mixed linear model estimated breed effects on mineral concentrations. No significant sire breed (P≥0.43) or dam breed (P≥0.20) effects were identified for mineral concentrations. Pearson correlation coefficients were calculated among mineral concentrations, carcass, and sensory traits. Zinc concentration was positively correlated (P≤0.05) with total iron (r=0.14), heme iron (r=0.13), and magnesium (r=0.19). Significant (P<0.05) correlations were identified between non-heme or heme iron and most traits in this study. Magnesium concentration was correlated with all carcass and palatability traits.

Analysis of genetic relationships and identification of lily cultivars based on inter-simple sequence repeat markers

Inter-simple sequence repeat (ISSR) markers were used to discriminate 62 lily cultivars of 5 hybrid series. Eight ISSR primers generated 104 bands in total, which all showed 100% polymorphism, and an average of 13 bands were amplified by each primer. Two software packages, POPGENE 1.32 and NTSYSpc 2.1, were used to analyze the data matrix. Our results showed that the observed number of alleles (NA), effective number of alleles (NE), Nei's genetic diversity (H), and Shannon's information index (I) were 1.9630, 1.4179, 0.2606, and 0.4080, respectively. The highest genetic similarity (0.9601) was observed between the Oriental x Trumpet and Oriental lilies, which indicated that the two hybrids had a close genetic relationship. An unweighted pair-group method with arithmetic means dendrogram showed that the 62 lily cultivars clustered into two discrete groups. The first group included the Oriental and OT cultivars, while the Asiatic, LA, and Longiflorum lilies were placed in the second cluster. The distribution of individuals in the principal component analysis was consistent with the clustering of the dendrogram. Fingerprints of all lily cultivars built from 8 primers could be separated completely. This study confirmed the effect and efficiency of ISSR identification in lily cultivars.

Escherichia coli type III secretion system 2: a new kind of T3SS?

Type III secretion systems (T3SSs) are employed by Gram-negative bacteria to deliver effector proteins into the cytoplasm of infected host cells. Enteropathogenic Escherichia coli use a T3SS to deliver effector proteins that result in the creation of the attaching and effacing lesions. The genome sequence of the Escherichia coli pathotype O157:H7 revealed the existence of a gene cluster encoding components of a second type III secretion system, the E. coli type III secretion system 2 (ETT2). Researchers have revealed that, although ETT2 may not be a functional secretion system in most (or all) strains, it still plays an important role in bacterial virulence. This article summarizes current knowledge regarding the E. coli ETT2, including its genetic characteristics, prevalence, function, association with virulence, and prospects for future work.

[Advance on the pathogenicity and immunological application of bacterial flagella--a review]

Being a surface structure of bacteria, flagella have been thought to simply act as the locomotive organelles for a long time. In recent years, as increasing information gathered from studies on the pathogenicity of flagella, we found flagella could contribute to invasion and adhesion to the host cells, playing an important role in the biofilm formation and being correlated with bacterial virulence secretion system. Binding of flagellin and toll-like receptor 5 may stimulate signaling pathway, resulting in the pro-inflammatory response. Meanwhile, flagella act as a new immune adjuvant as well, because of their good immunity character. This article summarizes the current knowledge of bacterial flagella, including their structure, contribution to the pathogenicity of the bacteria, and their potential application in immunity.

Polymorphisms in calpastatin and mu-calpain genes are associated with beef iron content

The objective of this study was to assess the association of markers in the calpastatin and mu-calpain loci with iron in beef cattle muscle. The population consisted of 259 cross-bred steers from Beefmaster, Brangus, Bonsmara, Romosinuano, Hereford and Angus sires. Total iron and heme iron concentrations were measured. Markers in the calpastatin (referred to as CAST) and mu-calpain (referred to as CAPN4751) genes were used to assess their association with iron levels. The mean and standard error for iron and heme iron content in the population was 35.6 ± 1.3 μg and 27.1 ± 1.4 μg respectively. Significant associations (P < 0.01) of markers were observed for both iron and heme iron content. For CAST, animals with the CC genotype had higher levels of iron and heme iron in longissimus dorsi muscle. For CAPN4751, individuals with the TT genotype had higher concentrations of iron and heme iron than did animals with the CC and CT genotypes. Genotypes known to be associated with tougher meat were associated with higher levels of iron concentration.

Flagellin and F4 fimbriae have opposite effects on biofilm formation and quorum sensing in F4ac+ enterotoxigenic Escherichia coli

Bacteria that form biofilms are often highly resistant to antibiotics and are capable of evading the host immune system. To evaluate the role of flagellin and F4 fimbriae on biofilm formation by enterotoxigenic Escherichia coli (ETEC), we deleted the fliC (encoding the major flagellin protein) and/or the faeG (encoding the major subunit of F4 fimbriae) genes from ETEC C83902. Biofilm formation was reduced in the fliC mutant but increased in the faeG mutant, as compared with the wild-type strain. The expression of AI-2 quorum sensing associated genes was regulated in the fliC and faeG mutants, consistent with the biofilm formation of these strains. But, deleting fliC and/or faeG also inhibited AI-2 quorum sensing activity.