Data-driven acoustic control of a spherical bubble using a Koopman linear quadratic regulator.

Koopman operator theory has gained interest as a framework for transforming nonlinear dynamics on the state space into linear dynamics on abstract function spaces, which preserves the underlying nonlinear dynamics of the system. These spaces can be approximated through data-driven methodologies, which enables the application of classical linear control strategies to nonlinear systems. Here, a Koopman linear quadratic regulator (KLQR) was used to acoustically control the nonlinear dynamics of a single spherical bubble, as described by the well-known Rayleigh-Plesset equation, with several objectives: (1) simple harmonic oscillation at amplitudes large enough to incite nonlinearities, (2) stabilization of the bubble at a nonequilibrium radius, and (3) periodic and quasiperiodic oscillation with multiple frequency components of arbitrary amplitude. The results demonstrate that the KLQR controller can effectively drive a spherical bubble to radially oscillate according to prescribed trajectories using both broadband and single-frequency acoustic driving. This approach has several advantages over previous efforts to acoustically control bubbles, including the ability to track arbitrary trajectories, robustness, and the use of linear control methods, which do not depend on initial guesses.

[LncRNA SOX2OT enhances 5-fluorouracil resistance of cholangiocarcinoma cells by promoting autophagy via up-regulating SIRT1 expression].

OBJECTIVE: To investigate the role of SIRT1/autophagy pathway in mediating the regulatory effect of lncRNA SOX2OT on 5-fluorouracil (5-FU) resistance in cholangiocarcinoma cells. METHODS: HCCC-9810 cells were used to construct a 5-FU-resistant cell model (HCCC-9810/5-FU cells), and the expression levels of lncRNA SOX2OT and SIRT1 mRNA and the protein expressions of SIRT1, Beclin1, LC3 and P62 were detected with qRT-PCR and Western blotting. The effects of transfection with a SOX2OT mimic on drug resistance and cell migration of HCCC-9810/5-FU cells were detected using CCK-8 assay and wound healing assay, and the changes in expressions of SOX2OT, SIRT1, Beclin1, LC3 and P62 were detected. Rescue experiment was performed by co-transfection of HCCC-9810/5-FU cells with both a SOX2OT-overexpressing plasmid and si-SIRT1 to confirm the role of SIRT1 in SOX2OT-mediated regulation of 5-FU resistance. A RNA pulldown assay was used to verify the targeted binding between SOX2OT and SIRT1. RESULTS: The proliferation of HCCC-9810 cells was significantly inhibited after treatment with different concentrations of 5-FU (P < 0.05). The 5-FU-resistant cells showed significantly increased protein expressions of SIRT1, Beclin1 and p62, an increased LC3 Ⅱ/LC3 Ⅰ ratio, and enhanced expressions of SIRT1 mRNA and SOX2OT (P < 0.05). Transfection of the resistant cells with SOX2OT mimic significantly enhanced cell migration and increased the protein expressions of SIRT1, Beclin1 and p62, the LC3Ⅱ/LC3Ⅰ ratio, and expression levels of SIRT1 mRNA and SOX2OT (P < 0.05), and these changes were obviously attenuated by SIRT1 knockdown, which also resulted in lowered 5-FU resistance of the cells without significantly affecting the expression level of SOX2OT (P > 0.05). RNA pulldown assay suggested that SOX2OT could directly bind to SIRT1. CONCLUSION: LncRNA SOX2OT enhances 5-FU resistance in HCCC-9810 cells by promoting autophagy through up-regulating SIRT1 expression.

[Solid placental transmogrification of the lung: A case report and literature review].

Placental transmogrification of the lung (PTL) is a very rare benign lung lesion. There are only about 40 cases reported in the literature. The imaging and histological features of PTL cases in the publication are various, most of which are cystic and a few of which are solid. Being extremely rare, the solid PTL is unknown to major pathologists and surgeons. We reported a case of solid PTL in the anterior mediastinum. The patient was a 52-year-old male with no history of smoking and without symptoms. During physical examination, chest CT revealed a circular low-density lesion with a maximum diameter of 2.9 cm beside the spine in the posterior basal segment of the left lower lobe of the lung. The wedge resection was performed by video-assisted thoracoscopy. Grossly, a round nodule was located underneath the visceral pleura. It was about 3.0 cm×3.0 cm×1.6 cm and the cut surface was grey-red, soft and spongy. Microscopically, the nodule was constituted of papillare, which resembled placental villi at low magnification. The axis of papillae was edema, in which some mild round cells with clear cytoplasm and CD10 positive staining aggregated and transitioned to immature adipocytes and amorphous pink materials deposited with a few of inflammatory cells infiltration. The surface of papillae was covered with disconti-nuous alveolar epithelium. Combined with the typical morphology and immunohistochemical characteristics of CD10 positive, the diagnosis was PTL. The patient was followed up for 1 year without recurrence and discomfort. So far, the pathogenesis of PTL is unclear. The major hypotheses include hamartoma, variant of emphysema and clonal hyperplasia of stromal cells. Based on the study of our case and publication, we speculate that the hyperplasia of stromal cells located in the alveolar septa might be the first step to form the solid PTL. With the progression of the disease, a typical unilateral cystic nodule develops as a result of secondary cystic degeneration due to the occlusive valve effect. Surgery is the only option for diagnosis and treatment of PTL. The clinician should make an individualized operation plan according to the clinical manifestations, location and scope of the lesion, and preserve the surrounding normal lung tissue as much as possible while completely removing the lesion. There is a favorable prognosis.

[Silencing SIRT1 reduces 5-fluorouracil resistance of cholangiocarcinoma cells by inhibiting the FOXO1/Rab7 autophagy pathway].

OBJECTIVE: To investigate the mechanism by which SIRT1 silencing reduces 5-fluorouracil (5-FU) resistance of cholangiocarcinoma cells and the role of FOXO1/Rab7 autophagy pathway in mediating this effect. METHODS: Human cholangiocarcinoma HCCC-9810 cells were treated with 50, 100, 150, and 200 µg/mL 5-FU to construct a 5-FU-resistant cell model, whose expressions of SIRT1, FOXO1 and Rab7 were detected with immunofluorescence assay, Western blotting and RTqPCR, and the expression levels of autophagy related proteins (Beclin1, LC3, and p62) were detected with Western blotting. The 5-FU resistant cells were transfected with a SIRT1 siRNA, and the changes in 5-Fu resistance and migration ability of the cells were evaluated using CCK-8 assay and wound healing assay; The changes in FOXO1 and Rab7 mRNA levels and protein expressions of SIRT1, FOXO1, Rab7, Beclin1, LC3 and P62 were detected with RT-qPCR and Western blotting. RESULTS: Treatments with 5-FU at 50, 100, 150, and 200 µg/mL all inhibited the proliferation of HCCC-9810 cells. Immunofluorescence assay revealed significantly enhanced SIRT1 expression in 5-FU-resistant HCC-9810 cells, and Western blotting also showed significantly up-regulated protein expressions of SIRT1, Rab7, P62, FOXO1 and Beclin 1 (P < 0.001) and an increased LC3II/LC3I ratio in the cells (P < 0.001). The mRNA levels of SIRT1, Rab7 and FOXO1 were also up-regulated in 5-Fu-resistant cells (P < 0.05). SIRT1 silencing significantly attenuated 5-FU resistance and migration ability of HCCC-9810 cells, and obviously decreased the protein expressions of SIRT1, Rab7, P62, FOXO1 and Beclin1 and the LC3II/LC3I ratio as well (P < 0.001). FOXO1 and Rab7 mRNA levels were significantly decreased in 5-FU-resistant HCC-9810 cells after SIRT1 silencing (P < 0.05). CONCLUSION: Silencing SIRT1 attenuates 5-FU resistance in HCC-9810 cells by inhibiting the activation of the FOXO1/Rab7 autophagy pathway.

[A preliminary study on the efficacy and safety of a new type of trabeculotome tunnelling trabeculoplasty for open-angle glaucoma].

Objective: To compare the efficacy and safety of trabeculotome tunnelling trabeculoplasty and gonioscopy-assisted transluminal trabeculotomy (GATT) in the treatment of open-angle glaucoma. Methods: A prospective randomized controlled study. The patients with open-angle glaucoma diagnosed in the ophthalmology center of Beijing Tongren Hospital affiliated to Capital Medical University from January to July 2022 were collected and divided into GATT group (undergoing GATT) and 3T group (undergoing 3T operation) using a random number table. Intraocular pressure (IOP) was recorded for both groups at 1 day, 1 week, 1 month, and 3 months after the operation, and the types and quantities of anti-glaucoma drugs used, postoperative complications, and surgical success rate were compared. Normal distribution measurement data were analyzed using independent sample t-tests, non-normal distribution measurement data were analyzed using non-parametric tests, and counting data were analyzed using chi-square tests. Results: This study included 35 patients (43 eyes), consisting of 27 males and 8 females, with an average age of (43.0±14.3) years. There were 21 patients (23 eyes) in the GATT group and 19 patients (20 eyes) in the 3T group. The maximum IOP without anti-glaucoma drugs before surgery, the highest IOP with the maximum number of anti-glaucoma drugs, and the IOP at 3 months after surgery in the GATT group were (33.5±9.1), (22.2±6.1), and (16.0±3.1) mmHg (1 mmHg=0.133 kPa), respectively. The corresponding values for the 3T group were (35.2±7.8), (21.5±6.8), and (16.1±2.0) mmHg. After surgery, the IOP in both groups was lower than before surgery, with a statistically significant difference (P<0.05) and no significant difference between the two groups (P>0.05). In the 3 months following surgery, 13 eyes in the GATT group and 11 eyes in the 3T group received more than two types of anti-glaucoma drugs, with no significant difference between the two groups (P>0.05). Three months after surgery, the complete and conditional success rates of the GATT group were 14/18 and 16/18, respectively, and those of the 3T group were 12/15 and 13/15, respectively, with no significant difference between the two groups (P>0.05). The incidence of hyphema, ciliary detachment, and shallow anterior chamber 1 day after surgery was 91%(21/23), 35%(8/23), and 30%(7/23), respectively, in the GATT group and 55%(11/20), 5%(1/20), and 0 in the 3T group, with a statistically significant difference between the two groups (P<0.05). Conclusion: 3T and GATT have similar success rates in the treatment of open-angle glaucoma. However, compared with GATT, 3T has fewer complications and is considered to be safer. (This article was published ahead of print on the Online-First Publishing Platform for Excellent Scientific Researches of Chinese Medical Association Publishing House on February 28, 2023).

Spectral control of nonclassical light pulses using an integrated thin-film lithium niobate modulator.

Manipulating the frequency and bandwidth of nonclassical light is essential for implementing frequency-encoded/multiplexed quantum computation, communication, and networking protocols, and for bridging spectral mismatch among various quantum systems. However, quantum spectral control requires a strong nonlinearity mediated by light, microwave, or acoustics, which is challenging to realize with high efficiency, low noise, and on an integrated chip. Here, we demonstrate both frequency shifting and bandwidth compression of heralded single-photon pulses using an integrated thin-film lithium niobate (TFLN) phase modulator. We achieve record-high electro-optic frequency shearing of telecom single photons over terahertz range (±641 GHz or ±5.2 nm), enabling high visibility quantum interference between frequency-nondegenerate photon pairs. We further operate the modulator as a time lens and demonstrate over eighteen-fold (6.55 nm to 0.35 nm) bandwidth compression of single photons. Our results showcase the viability and promise of on-chip quantum spectral control for scalable photonic quantum information processing.

Effect of Hypoxic-Ischemic Brain Injury in Neonatal Rats on Behavioral Parameters and Expression of CDK8 in the Brain Tissue.

Behavioral changes in newborn 3-day-old rats (n=44) with modeled hypoxic-ischemic brain injury (HIBI) were observed, and the expression of CDK8 in brain tissues was detected to clarify the significance of CDK8. In 30 min, 3 h, and 3 days after HIBI, the left (ischemic) hemisphere was taken for examination. In 3 days after HIBI, the rat pups were examined in the behavioral tests. In rat pups with HIBI, changes of CDK8 expression were detected by Western blotting and real-time PCR and changes in the righting reflex and forelimb grip strength test (p<0.05) were revealed in comparison with sham-operated animals. The expression of CDK8 increased 30 min after HIBI and decreased in 3 h and 3 days. Hypoxia and ischemia of the left brain may affect locomotion, but not sensation. Since CDK8 is involved in the immune response after cerebral hypoxia and ischemia, this kinase can be used as an early diagnostic index.

Spectrally separable photon-pair generation in dispersion engineered thin-film lithium niobate.

Existing nonlinear-optic implementations of pure, unfiltered heralded single-photon sources do not offer the scalability required for densely integrated quantum networks. Additionally, lithium niobate has hitherto been unsuitable for such use due to its material dispersion. We engineer the dispersion and the quasi-phasematching conditions of a waveguide in the rapidly emerging thin-film lithium niobate platform to generate spectrally separable photon pairs in the telecommunications band. Such photon pairs can be used as spectrally pure heralded single-photon sources in quantum networks. We estimate a heralded-state spectral purity of >94% based on joint spectral intensity measurements. Further, a joint spectral phase-sensitive measurement of the unheralded time-integrated second-order correlation function yields a heralded-state purity of (86±5)%.

Supervised dimension reduction for optical vapor sensing.

Detecting and identifying vapors at low concentrations is important for air quality assessment, food quality assurance, and homeland security. Optical vapor sensing using photonic crystals has shown promise for rapid vapor detection and identification. Despite the recent advances of optical sensing using photonic crystals, the data analysis method commonly used in this field has been limited to an unsupervised method called principal component analysis (PCA). In this study, we applied four different supervised dimension reduction methods on differential reflectance spectra data from optical vapor sensing experiments. We found that two of the supervised methods, linear discriminant analysis and least-squares regression PCA, yielded better interclass separation, vapor identification and improved classification accuracy compared to PCA.

MiR-302b Suppresses Tumor Metastasis by Targeting Frizzled 6 in OSCC.

Oral squamous cell carcinoma (OSCC) accounts for approximately 90% of malignant epithelial tumors of the oral and maxillofacial region. OSCC has high rate of metastasis and poor prognosis. Tobacco and/or alcohol consumption and human papillomavirus infection are relatively exact susceptibility factors for OSCC, but the specific process of oral mucosal carcinogenesis and progression is very complicated. microRNA-302b (miR-302b) could regulate various characteristics of many tumor cells, such as proliferation and apoptosis, but its role and mechanism in OSCC have not been reported. This research aims to study the effect of miR-302b on the invasion and migration ability of OSCC and the mechanism by which it functions as well as to identify new prognostic indicators and therapeutic targets for OSCC patients. Functional studies showed that the miR-302b level was negatively correlated with the invasion and migration ability of OSCC. The studies also showed that the overexpression of miR-302b could attenuate the invasion and migration ability of OSCC cells and reduce lymphangiogenesis and the lung metastasis rate of OSCC cells in a mouse model. Mechanistic studies were performed by quantitative polymerase chain reactions, luciferase assays, and RNA pull-down experiments. The results verified that frizzled class receptor 6 (FZD6) is a target gene of miR-302b in OSCC that could promote cell invasion and migration. Clinical studies demonstrate that the protein expression level of FZD6 was higher in OSCC and metastatic lymph nodes than in normal oral mucosa epithelium. Taken together, these data showed that miR-302b could inhibit the invasion and migration ability of OSCC cells by targeting and downregulating FZD6, thereby inhibiting OSCC metastasis. As a new target gene of miR-302b, FZD6 has the potential to become a prognostic and therapeutic target for OSCC patients.

[Predictive factors of pathological complete response after neoadjuvant chemoradiotherapy for middle-low rectal cancer].

Objective: To explore the predictive factors of pathological complete response (pCR) after neoadjuvant chemoradiotherapy for middle-low rectal cancer. Methods: A case-control study was conducted. The inclusion criteria were as follows: (1) colonoscopy, digital examination or magnetic resonance imaging (MRI) showed a distance from the lower edge of the tumor to the dentate line of no more than 10 cm; (2) complete clinicopathological data were available; (3) preoperative biopsy revealed adenocarcinoma; (4) preoperative pelvic MRI or endorectal ultrasonography was performed; (5) no distant metastasis was found. Exclusion criteria: (1) preoperative radiotherapy and chemotherapy were not administrated according to the standard; (2) simultaneous multiple primary cancer and familial adenomatous polyposis were observed. According to the above criteria, clinicopathological data of 245 patients with middle-low rectal cancer undergoing preoperative neoadjuvant chemoradiotherapy in Changhai Hospital of Navy Medical University from January 2012 to December 2019 were retrospectively collected. Univariate analysis and multivariate logistic analysis were used to identify the clinical factors predicting pCR. pCR is defined as complete disappearance of cancer cells under the microscope in cancer specimens (including lymph nodes) after neoadjuvant chemoradiotherapy. Results: A total of 72 patients with pCR were enrolled in this study. Univariate analysis showed that preoperative T stage, tumor circumference, tumor morphology, carbohydrate antigen (CA) 19-9, interval between the end of neoadjuvant therapy and operation were associated with pCR (all P<0.05). The above 5 variables were included in multivariate logistic analysis and the results revealed that the T stage (OR=5.743, 95% CI: 2.416-13.648, P<0.001), tumor circumference (OR=7.754, 95% CI: 3.822-15.733, P<0.001), tumor morphology (OR=0.264, 95% CI: 0.089-0.786, P=0.017) and the interval between the end of neoadjuvant therapy and operation (OR=0.303, 95% CI: 0.147-0.625, P=0.001) were independent predictive factors of pCR, while CA 19-9 level was not an independent factor (OR=1.873, 95% CI:0.372-9.436, P=0.447). Conclusion: By knowing the clinical features of preoperative T stage, tumor circumference, tumor morphology and the interval between neoadjuvant chemoradiotherapy and operation, patients with higher likelyhood of pCR after neoadjuvant chemoradiotherapy may be identified.

LncRNA INHBA-AS1 promotes colorectal cancer cell proliferation by sponging miR-422a to increase AKT1 axis.

OBJECTIVE: In recent years, long non-coding RNAs (lncRNAs) have emerged for regulating the development, as well as progression in colorectal cancer (CRC), which assists in finding new targets for CRC treatment. A previous study indicated that INHBA-AS1 promotes oral squamous cell progression by sponging miR-143-3p. However, the exact function possessed by lncRNA INHBA-AS1 in CRC development remains unclear. PATIENTS AND METHODS: The expression level of INHBA-AS1 in CRC tissues and cell lines was determined by qRT-PCR. The functional role of INHBA-AS1 in CRC was investigated by a series of in vitro assays. RNA immunoprecipitation (RIP), bioinformatics analysis was utilized to explore the potential mechanisms of INHBA-AS1. RESULTS: The present study identified INHBA-AS1 as a kind of lncRNA with high expression in CRC tissues and cells. Functionally, NHBA-AS1 downregulation in CRC cells suppressed CRC cell proliferation as well as colony formability. Mechanistically, INHBA-AS1/miR-422a/AKT1 established the ceRNA network to regulate MMP-2, -7, -9 expressions that participated the modulation of CRC progression. CONCLUSIONS: In summary, LncRNA INHBA-AS1 contributes to CRC progression through AKT1 pathway, and provides a new mechanism to regulate CRC development, as well as a potential target for treating CRC.

LncRNA PWRN2 stimulates the proliferation and migration in papillary thyroid carcinoma through the miR-325/DDX5 axis.

OBJECTIVE: The objective of this study was to illustrate the role of long non-coding RNA (lncRNA) PWRN2 in the development of papillary thyroid carcinoma (PTC) and the potential mechanism. PATIENTS AND METHODS: Expression levels of PWRN2, miR-325 and DDX5 in 32 PTC tissues and paired normal ones were detected. The interaction in the PWRN2/miR-325/DDX5 axis was assessed by Luciferase assay. At last, the roles of the PWRN2/miR-325/DDX5 axis in regulating proliferative and migratory potentials in PTC were examined. RESULTS: It was found that PWRN2 was upregulated and miR-325 was downregulated in PTC tissues and cell lines. MiR-325 level was negatively correlated with PWRN2 level in PTC samples, and the overexpression of PWRN2 stimulated proliferative and migratory potentials in PTC cells, which were partially abolished by overexpression of miR-325. In addition, DDX5 was the target gene binding to miR-325, and its level was negatively regulated by miR-325. Moreover, Luciferase assay and rescue experiments confirmed that the PWRN2/miR-325/DDX5 axis aggravated the development of PTC. CONCLUSIONS: LncRNA PWRN2 stimulates proliferative and migratory potentials in PTC through sponging miR-325 to upregulate DDX5.

Hyperprogressive disease during PD-1/PD-L1 blockade in patients with non-small-cell lung cancer.

BACKGROUND: Immune checkpoint blockade with Programmed cell death 1 (PD-1)/PD-L1 inhibitors has been effective in various malignancies and is considered as a standard treatment modality for patients with non-small-cell lung cancer (NSCLC). However, emerging evidence show that PD-1/PD-L1 blockade can lead to hyperprogressive disease (HPD), a flair-up of tumor growth linked to dismal prognosis. This study aimed to evaluate the incidence of HPD and identify the determinants associated with HPD in patients with NSCLC treated with PD-1/PD-L1 blockade. PATIENTS AND METHODS: We enrolled patients with recurrent and/or metastatic NSCLC treated with PD-1/PD-L1 inhibitors between April 2014 and November 2018. Clinicopathologic variables, dynamics of tumor growth, and treatment outcomes were analyzed in patients with NSCLC who received PD-1/PD-L1 blockade. HPD was defined according to tumor growth kinetics (TGK), tumor growth rate (TGR), and time to treatment failure (TTF). Immunophenotyping of peripheral blood CD8+ T lymphocytes was conducted to explore the potential predictive biomarkers of HPD. RESULTS: A total of 263 patients were analyzed. HPD was observed in 55 (20.9%), 54 (20.5%), and 98 (37.3%) patients according to the TGK, TGR, and TTF. HPD meeting both TGK and TGR criteria was associated with worse progression-free survival [hazard ratio (HR) 4.619; 95% confidence interval (CI) 2.868-7.440] and overall survival (HR, 5.079; 95% CI, 3.136-8.226) than progressive disease without HPD. There were no clinicopathologic variables specific for HPD. In the exploratory biomarker analysis with peripheral blood CD8+ T lymphocytes, a lower frequency of effector/memory subsets (CCR7-CD45RA- T cells among the total CD8+ T cells) and a higher frequency of severely exhausted populations (TIGIT+ T cells among PD-1+CD8+ T cells) were associated with HPD and inferior survival rate. CONCLUSION: HPD is common in NSCLC patients treated with PD-1/PD-L1 inhibitors. Biomarkers derived from rationally designed analysis may successfully predict HPD and worse outcomes, meriting further investigation of HPD.

Polymorphisms in lncRNA PTENP1 and the risk of oral squamous cell carcinoma in a Chinese population.

OBJECTIVE: PTENP1, a long noncoding RNA, has previously been reported to be involved in tumorigenesis and cancer progression. The relationship between PTENP1 and susceptibility tumors is reported, while, an association of PTENP1 with the risk of oral squamous cell carcinoma (OSCC) in Chinese population is lacked. This research is designed to investigate the association of PTENP1 with susceptibility of OSCC. PATIENTS AND METHODS: In this research, TaqMan technology was used to test genotype in 342 OSCC patients and 711 healthy controls, so as to analyze the association between PTENP1 polymorphisms (rs7853346 rs865005 and rs10971638) and susceptibility of oral squamous cell carcinoma. RESULTS: The results of this research showed that rs7853346 [Additive model: Adjusted odds ratio (OR) = 0.81, 95% confidence interval (CI) = 0.66-0.99] was related to the OSCC risk. It was not found that the other two sites were associated with the susceptibility of OSCC. CONCLUSIONS: This research indicated that rs7853346 is statistically correlated with the OSCC risk.

Rapid specific and visible detection of porcine circovirus type 3 using loop-mediated isothermal amplification (LAMP).

In this study, a rapid and specific assay for the detection of porcine circovirus type 3 (PCV3) was established using loop-mediated isothermal amplification (LAMP). Four primers were specifically designed to amplify PCV3. The LAMP assay was effectively optimized to amplify PCV3 by water bath at 60°C for 60 min. The detection limit was approximately 1 × 101 copy in this LAMP assay. Compared to porcine circovirus type 2 (PCV2), both gE and gD genes of pseudorabies virus (PRV) and porcine parvovirus (PPV), the LAMP assay showed a high specific detection of PCV3. A visible detection method was developed using SYBR Green I to recognize the results rapidly. Based on the detection of 20 clinical tissue samples, the LAMP assay was more practical and convenient than classical PCR due to its simplicity, high sensitivity, rapidity, specificity, visibility and cost efficiency.

In Vivo Biochemistry: Single-Cell Dynamics of Cyclic Di-GMP in Escherichia coli in Response to Zinc Overload.

Intracellular signaling enzymes drive critical changes in cellular physiology and gene expression, but their endogenous activities in vivo remain highly challenging to study in real time and for individual cells. Here we show that flow cytometry can be performed in complex media to monitor single-cell population distributions and dynamics of cyclic di-GMP signaling, which controls the bacterial colonization program. These in vivo biochemistry experiments are enabled by our second-generation RNA-based fluorescent (RBF) biosensors, which exhibit high fluorescence turn-on in response to cyclic di-GMP. Specifically, we demonstrate that intracellular levels of cyclic di-GMP in Escherichia coli are repressed with excess zinc, but not with other divalent metals. Furthermore, in both flow cytometry and fluorescence microscopy setups, we monitor the dynamic increase in cellular cyclic di-GMP levels upon zinc depletion and show that this response is due to de-repression of the endogenous diguanylate cyclase DgcZ. In the presence of zinc, cells exhibit enhanced cell motility and increased sensitivity to antibiotics due to inhibited biofilm formation. Taken together, these results showcase the application of RBF biosensors in visualizing single-cell dynamic changes in cyclic di-GMP signaling in direct response to environmental cues such as zinc and highlight our ability to assess whether observed phenotypes are related to specific signaling enzymes and pathways.

Presence of Torque teno sus virus 1 and 2 in porcine circovirus 3-positive pigs.

In this study, the co-infection of Torque teno sus virus (TTSuV) and porcine circovirus type 3 (PCV3) was reported. One hundred and ten of 132 (83.3%) PCV3-positive samples were co-infected with Torque teno sus virus 1 (TTSuV1). Ninety-four of 132 (71.2%) PCV3-positive samples were co-infected with Torque teno sus virus 2 (TTSuV2). Sixty-six of 132 (50.0%) of PCV3-positive samples were co-infected with both TTSuV1 and TTSuV2. There were no clinical signs of infection in pigs that were both PCV3-positive and PCV2-negative, in either multiparous sows or live-born infants. The high co-infection rate provides valuable information for the further study of the pathological correlation between PCV3 and TTSuVs.

Live Flow Cytometry Analysis of c-di-GMP Levels in Single Cell Populations.

Second-generation RNA-based fluorescent biosensors have been developed that enable flow cytometry experiments to monitor the population dynamics of c-di-GMP signaling in live bacteria. These experiments are high-throughput, provide information at the single-cell level, and can be performed on cells grown in complex media and/or under anaerobic conditions. Here, we describe flow cytometry methods for three applications: (1) high-throughput screening for diguanylate cyclase activity, (2) analyzing c-di-GMP levels under anaerobic conditions, and (3) monitoring cell population dynamics of c-di-GMP levels upon environmental changes. These methods showcase RNA-based fluorescent biosensors as versatile tools for studying c-di-GMP signaling in bacteria.

The occurrence of porcine circovirus 3 without clinical infection signs in Shandong Province.

Porcine circovirus type 3 (PCV3) was detected in Shandong, China. One hundred and thirty-two of 222 (59.46%) samples were PCV3 positive, while 52 of 132 (39.39%) samples were co-infected with PCV2. There were no clinical signs of infection in either multiparous sows or live-born infants. Two strains of PCV3 were indentified from natural stillborn foetuses. Phylogenetic analysis showed the two strains of PCV3 are 96% identical to the known PCV3/Pig/USA (KX778720.1, KX966193.1 and KX898030.1) and closely related to Barbel Circovirus. Further studies of the epidemiology of PCV3 and the co-infection with PCV2 are needed.