Quantification of Viable Cells of Pseudomonas syringae pv. tomato in Tomato Seed Using Propidium Monoazide and a Real-Time PCR Assay.

Pseudomonas syringae pv. tomato is a seedborne pathogen that causes bacterial speck disease in tomato. P. syringae pv. tomato is typically detected in tomato seed using quantitative real-time PCR (qPCR) but the inability of qPCR to distinguish between viable and nonviable cells might lead to an overestimation of viable P. syringae pv. tomato cells. In the present study, a strategy involving a propidium monoazide (PMA) pretreatment followed by a qPCR (PMA-qPCR) assay was developed for quantifying viable P. syringae pv. tomato cells in contaminated tomato seed. PMA could selectively bind to the chromosomal DNA of dead bacterial cells and, therefore, block DNA amplification of qPCR. The primer pair Pst3F/Pst3R was designed based on gene hrpZ to specifically amplify and quantify P. syringae pv. tomato by qPCR. The PMA pretreatment protocol was optimized for selectively detecting viable P. syringae pv. tomato cells, and the optimal PMA concentration and light exposure time were 10 µmol liter-1 and 10 min, respectively. In the sensitivity test, the detection limit of PMA-qPCR for detecting viable cells in bacterial suspension and artificially contaminated tomato seed was 102 CFU ml-1 and 11.86 CFU g-1, respectively. For naturally contaminated tomato seed, viable P. syringae pv. tomato cells were quantified in 6 of the 19 samples, with infestation levels of approximately 102 to 104 CFU g-1. The results indicated that the PMA-qPCR assay is a suitable tool for quantifying viable P. syringae pv. tomato cells in tomato seed, which could be useful for avoiding the potential risks of primary inoculum sources from contaminated seed.

Schwannomatosis patient who was followed up for fifteen years: A case report.

BACKGROUND: Schwannomatosis is a rare disease characterized by multiple schwannomas of the whole body. Although benign, schwannomatosis that occurs in important areas of the body, such as the brain and spinal canal, can cause considerable disability and mortality. The disease is rare, frequent and relapsing, and this poses a diagnostic and therapeutic challenge. CASE SUMMARY: A 40-year-old male had multiple masses all over his body, starting at the age of 19. Four years prior, he started to experience a progressive decrease in muscle strength in both lower limbs and developed urinary and defecation dysfunctions, and gradual paralysis. One month prior, the patient developed pain and numbness in his left forearm. The patient had undergone five surgical procedures for this disease in our department. Based on the family history, imaging examinations, pathological biopsy and molecular biological examinations, the diagnosis of schwannomatosis was confirmed. This time, the patient was admitted to our hospital again for a 6th operation because of the pain and numbness in his left forearm. After the operation, the patient's symptoms improved significantly; the patient recovered and was discharged from the hospital. At the last telephone follow-up, the patient reported a poor general condition but was alive. CONCLUSION: Here, we report a rare case of schwannomatosis. We conducted 15 years of patient follow-up and treatment, and analyzed the timing of surgery and patient psychology. This case will further extend our overall understanding of the diagnosis and treatment of this rare tumor.

[A citation analysis of Chinese Journal of Ophthalmology from 2005 to 2009].

OBJECTIVE: To evaluate the academic level and the quality of Chinese Journal of Ophthalmology (CJO) by analyzing its citation status. METHODS: Bibliometrics was used to analyze and evaluate the distribution of original papers in CJO in 2005-2009 based on the data of Chinese Medical Citation Index (CMCI). RESULTS: A total of 1358 papers were published in CJO between 2005 and 2009. Among them, 695 were cited for 2333 times, with an average of 3.36 times per cited paper. The papers were cited by authors from 26 provinces or municipalities or autonomous regions, Hongkong and Macao, China, as well as 2 from United States. The regions from where the papers had the highest citation were Beijing (202 times), Shanghai (93), Guangdong (82) and Shandong (69). The institutions with the highest citation rates were Zhongshan Ophthalmic Center of Sun Yat-Sen University (349 times) and Beijing Tongren Eye Center (265). CJO had been cited by more than 300 other journals in the past 5 years, such as International Ophthalmology, Ophthalmology and Chinese Journal of Practical Ophthalmology. CONCLUSIONS: CJO, which is the journal with the high quality and citation rate, is one of the resources with important information in ophthalmology. It is one of the prestigious medical journals in China.

Electrophysiological study on differentiation of rat bone marrow stromal stem cells into neuron-like cells in vitro by edaravone.

OBJECTIVE: To explore the electrophysiological properties of differentiation of rat bone marrow-derived stromal stem cells (rBMSCs) to neuron-like cells in vitro by edaravone, a new type of free radical scavenger. METHODS: Stromal stem cells were separated from rat bone marrow with Ficoll-Paque reagent and expanded in different culture medium in vitro. rBMSCs were induced by edaravone containing serum-free L-DMEM. Morphologic observation and Western blot analysis including the expression of Nav1.6, Kv1.2, Kv1.3, Cav1.2 were performed, and whole patch-clamp technique was used. RESULTS: Cyton contraction and long processes were shown in differentiated stromal stem cells. Nav1.6, Kv1.2, Kv1.3 and Cav1.2 were expressed in both differentiated and undifferentiated cells. However, the expression of channel proteins in differentiated cells was up-regulated. Consistently, their resting potential and outward currents were also enhanced in the differentiated cells, which was especially significant in the outward rectifier potassium current. CONCLUSION: In vitro, neuron-like cells derived from rBMSCs, induced by edaravone, possess electrophysiological properties of neurons.

Differentiation of human bone marrow mesenchymal stem cells into neuron-like cells in vitro.

STUDY DESIGN: Responses of human mesenchymal stem cells from bone marrow (hBMSCs) were analyzed under chemical conditions, and then characterization of ion channels was evaluated by whole-cell patch clamp. OBJECTIVE: To explore the possibility of differentiation of human bone marrow-derived mesenchymal stem cells into neuron-like cells in vitro under different conditions. SUMMARY OF BACKGROUND DATA: The generation of mesenchymal stem cells into neuron-like cells has been studied. However, few of these studies characterized functional properties of the differentiated hBMSCs. METHODS: hBMSCs (Passage 2) were expanded and cultured in vitro. After Passage 5 was subcultured, the cells were induced by cytokines and antioxidants. Morphologic observation, immunocytochemistry, Western blot analysis, and patch-clamp techniques were performed to evaluate properties of treated and control groups. RESULTS: The differentiated neuronal cells from hBMSCs not only expressed neuron phenotype and membrane channel protein including Nav1.6, Kv1.2, Kv1.3, and Cav1.2 but also exhibited functional ion currents. Both hBMSCs and differentiated cells expressed Nav1.6, Kv1.2, Kv1.3, and Cav1.2 and voltage-activated potassium currents, including delayed rectifier, noise-like and transient outward currents. However, expression of channel proteins, such as sodium channel Nav1.6 and potassium channels Kv1.2 and Kv1.3, were upregulated. Consistently, their potassium currents were also enhanced in the differentiated cells. CONCLUSION: hBMSCs possess of great potential to differentiate into functional neurons, indicating that hBMSCs may be an ideal cell source in managing a variety of clinical diseases such as spinal cord injury.