Gram-negative quorum sensing signalling enhances biofilm formation and virulence traits in gram-positive pathogen Enterococcus faecalis

Acyl-homoserine lactones (AHLs) are typical quorum-sensing molecules of gram-negative bacteria. Recent evidence suggests that AHLs may also affect gram-positives, although knowledge of these interactions remains scarce. Here, we assessed the effect of AHLs on biofilm formation and transcriptional regulations in the gram-positive Enterococcus faecalis. Five E. faecalis strains were investigated herein. Crystal violet was employed to quantify the biomass formed, and confocal microscopy in combination with SYTO9/PI allowed the visualisation of biofilms' structure. The differential expression of 10 genes involved in quorum-sensing, biofilm formation and stress responses was evaluated using reverse-transcription-qPCR. The AHL exposure significantly increased biofilm production in strain ATCC 29212 and two isolates from infected dental roots, UmID4 and UmID5. In strains ATCC 29212 and UmID7, AHLs up-regulated the quorum-sensing genes (fsrC, cylA), the adhesins ace, efaA and asa1, together with the glycosyltransferase epaQ. In strain UmID7, AHL exposure additionally up-regulated two membrane-stress response genes (σ^V, groEL) associated with increased stress-tolerance and virulence. Altogether, our results demonstrate that AHLs promote biofilm formation and up-regulate a transcriptional network involved in virulence and stress tolerance in several E. faecalis strains. These data provide yet-unreported insights into E. faecalis biofilm responses to AHLs, a family of molecules long-considered the monopole of gram-negative signalling.

Protein overexpression of toll-like receptor 4 and myeloid differentiation factor 88 in oral squamous cell carcinoma and clinical significance

Oral squamous cell carcinoma (OSCC) is the most common type of malignancy of the head and neck. In the present study, the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) was evaluated in 55 OSCC tissues and their corresponding adjacent tissues using immunohistochemistry and reverse-transcription quantitative PCR. The results indicated that TLR4 and MyD88 were overexpressed in OSCC. Furthermore, high expression of MyD88 was negatively associated with a poor degree of differentiation, recurrence and metastasis of the tumor and was positively associated with underlying disease, including hypertension, heart disease and diabetes mellitus. Furthermore, high expression of TLR4 was positively associated with a long growth time of the tumor. In conclusion, the present study evaluated the expression levels of TLR4 and MyD88 in OSCC, as well as the association between them and clinicopathological factors, to provide markers for the prognosis and treatment of OSCC. These two genes may serve as biomarkers to optimize OSCC treatment, setting a new direction for stratifying patients and developing precise and personalized treatment regimens; the TLR4/MyD88 pathway may serve as a potential therapeutic target in the future.

Highly Selective Multiplex Quantitative Polymerase Chain Reaction with a Nanomaterial Composite Hydrogel for Precise Diagnosis of Viral Infection

As viruses have been threatening global public health, fast diagnosis has been critical to effective disease management and control. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) is now widely used as the gold standard for detecting viruses. Although a multiplex assay is essential for identifying virus types and subtypes, the poor multiplicity of RT-qPCR makes it laborious and time-consuming. In this paper, we describe the development of a multiplex RT-qPCR platform with hydrogel microparticles acting as independent reactors in a single reaction. To build target-specific particles, target-specific primers and probes are integrated into the particles in the form of noncovalent composites with boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs). The thermal release characteristics of DNA, primer, and probe from the composites of primer-BNNT and probe-CNT allow primer and probe to be stored in particles during particle production and to be delivered into the reaction. In addition, BNNT did not absorb but preserved the fluorescent signal, while CNT protected the fluorophore of the probe from the free radicals present during particle production. Bicompartmental primer-incorporated network (bcPIN) particles were designed to harness the distinctive properties of two nanomaterials. The bcPIN particles showed a high RT-qPCR efficiency of over 90% and effective suppression of non-specific reactions. 16-plex RT-qPCR has been achieved simply by recruiting differently coded bcPIN particles for each target. As a proof of concept, multiplex one-step RT-qPCR was successfully demonstrated with a simple reaction protocol.

Low expression of KIF7 indicates poor prognosis in epithelial ovarian cancer

The aim of the present study was to investigate kinesin family member 7 (KIF7) expression in epithelial ovarian cancer tissues (paraffin-embedded tissues and fresh) and to explore its expression, association with clinicopathological parameters and prognostic value in patients with epithelial ovarian cancer. A total of 113 paraffin-embedded tumor tissues of epithelial ovarian cancer patients diagnosed and operated at the memorial hospital of Sun Yat-sen University Between December 2009 and March 2017 and 41 paratumor tissues were collected for the present study and were assessed for KIF7 expression using immunohistochemistry. Furthermore, 22 fresh epithelial ovarian cancer tissues and their matched paratumor tissues were collected from the Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, between August 2013 and March 2019 and subjected to reverse-transcription quantitative PCR analysis to detect the mRNA expression of KIF7. The expression of KIF7 was lower in cancer tissues than in paratumor tissues, and KIF7 expression was associated with recurrence-free survival and overall survival in epithelial ovarian cancer patients. Furthermore, multivariate logistic regression analysis indicated that low KIF7 expression was an independent predictor of poor survival in patients with epithelial ovarian cancer. In conclusion, KIF7 has a tumor suppressor role in epithelial ovarian cancer and is a useful independent prognostic predictor. It may hold important value for the clinical diagnosis and treatment of epithelial ovarian cancer.

Identification of stable genes in the corpus luteum of lactating Holstein cows in pregnancy and luteolysis: Implications for selection of reverse-transcription quantitative PCR reference genes

In lactating dairy cattle, the corpus luteum (CL) is a dynamic endocrine tissue vital for pregnancy maintenance, fertility, and cyclicity. Understanding processes underlying luteal physiology is therefore necessary to increase reproductive efficiency in cattle. A common technique for investigating luteal physiology is reverse-transcription quantitative PCR (RT-qPCR), a valuable tool for quantifying gene expression. However, reference-gene-based RT-qPCR quantification methods require utilization of stably expressed genes to accurately assess mRNA expression. Historically, selection of reference genes in cattle has relied on subjective selection of a small pool of reference genes, many of which may have significant expression variation among different tissues or physiologic states. This is particularly concerning in dynamic tissues such as the CL, with its capacity for rapid physiologic changes during luteolysis, and likely in the less characterized period of CL maintenance during pregnancy. Thus, there is a clear need to identify reference genes well suited for the bovine CL over a wide range of physiological states. Whole-transcriptome RNA sequencing stands as an effective method to identify new reference genes by enabling the assessment of the expression profile of the entire pool of mRNA transcripts. We report the identification of 13 novel putative reference genes using RNA sequencing in the bovine CL throughout early pregnancy and luteolysis: RPL4, UQCRFS1, COX4I1, RPS4X, SSR3, CST3, ZNF266, CDC42, CD63, HIF1A, YWHAE, EIF3E, and PPIB. Independent RT-qPCR analyses were conducted confirming expression stability in another set of CL tissues from pregnancy and regression, with analyses performed for 3 groups of samples: (1) all samples, (2) samples from pregnancy alone, and (3) samples throughout the process of CL regression. Seven genes were found to be more stable in all states than 2 traditional reference genes (ACTB and GAPDH): RPS4X, COX4I1, PPIB, SSR3, RPL4, YWHAE, and CDC42. When CL tissues from pregnant animals alone were analyzed, CST3, HIF1A, and CD63 were also identified as more stable than ACTB and GAPDH. Identification of these new reference genes will aid in accurate normalization of RT-qPCR results, contributing to proper interpretation of gene expression relevant to luteal physiology. Furthermore, our analysis sheds light on the effects of luteolysis and pregnancy on the stability of gene expression in the bovine CL.

Development of a reverse transcription quantitative real-time PCR-based system for rapid detection and quantitation of hepatitis delta virus in the western Amazon region of Brazil

The hepatitis delta virus (HDV) is a pathogen that causes a severe and rapidly progressive disease of hepatocytes. The measurement of viral load in the peripheral blood of patients with HDV infections is important for diagnosis, treatment monitoring, and support for follow-up studies of viral replication during the course of the disease. This study reports the development of an assay capable of detecting and quantifying the abundance of HDV particles in serum samples, based on reverse-transcription quantitative PCR (RT-qPCR). Two standards for calibration were produced for determining the viral load of HDV: a cDNA cloned into a linear plasmid and a transcribed RNA. For validating this assay, 140 clinical samples of sera were used, comprising 100 samples from patients who tested positive for anti-HDV and hepatitis B virus surface antigen (HBsAg) by ELISA; 30 samples from blood donors; 5 samples monoinfected with hepatitis B virus (HBV); and 5 samples monoinfected with hepatitis C virus (HCV). The HDV RT-qPCR assay performed better when calibrated using the standard based on HDV cDNA cloned into a linear plasmid, yielding an efficiency of 99.8% and a specificity of 100% in the in vitro assays. This study represents the first HDV RT-qPCR assay developed with clinical samples from Brazil and offers great potential for new clinical efficacy studies of antiviral therapeutics for use in patients with hepatitis delta in the western Amazon region.