Analysis of Staphyloxanthin Biosynthesis Using Single Cell Raman Spectroscopy / 分析化学

Laser tweezers Raman spectroscopy ( LTRS ) was used to study the inhibitory effect of indol on staphyloxanthin biosynthesis in Staphylococcus aureus cells and the dynamic changes of this pigment content inside bacterial cells during batch cultivation. The Raman spectra of Staphylococcus aureus cells cultivated for different time and exposed to various doses of indol were acquired. The intensity of 1523 cm-1 band was used for the quantification of staphyloxanthin, in the meantime, the pigment was measured by UV spectrometry. The experimental result showed that an excellent linear relationship existed between the intensities of Raman peak at 1523 cm-1 of bacterial cells and the pigment contents estimated by UV spectrometry, with a correlation coefficient of 0 . 9772 . The spectral data at population level as well as single cell level revealed that indol could inhibit the production of pigment in dose-dependent manner, and the pigment content in bacterial cells incubated with indol decreased by 70%. Under the batch growth condition, the pigment amount in Staphylococcus aureus cells reached the maximum value during the middle exponential growth phase ( 12 h ) and the heterogeneity of pigment content in bacterial cells within certain populations at various time points was relatively small, with RSDs of 39. 2% to 61. 1%. This investigation indicates that LTRS can be served as a reliable method for the analysis of staphyloxanthin content at single cell level.

The Correlation of mild cognitive impairment with mild cognitive impairment / 中国医师进修杂志

Objective To investigate the correlation between cerebral artery stenosis (MCAS) and mild cognitive impairment (MCI).Methods Continuous selected 636 cases of 50-80 years old inpatients or outpatients who examined by transcranial color Doppler ultrasound (TCD) in April 2012 to April 2013 in our hospital.Keep the mini-mental state examination (MMSE) and clinical dementia rating (CDR) as the evaluation of cognitive function.Results Detected 124 cases of MCAS patients (MCAS group) and 512 cases of non-MCAS patients (non-MCAS group).Forty-four cases MCI were detected in MCAS group with the prevalence rate was 35.5％(44/124),and 114 cases of patients with MCI were detected in non-MCAS group with the prevalence rate was 22.3％ (114/512),the difference was statistically significant (P ＜ 0.05).Single factor analysis showed that there were no significant difference between two groups in waist circumference,hypertension,coronary heart disease,hyperlipidemia,smoking,diastolic blood pressure and total cholesterol,uric acid,fasting glucose,C-reactive protein (P ＞ 0.05); There were significantly different between two groups in age,gender,education level,MCAS,history of diabetes,systolic blood pressure and triglyceride,low density lipoprotein-cholesterol,high-density lipoprotein-cholesterol(P ＜ 0.05).Multiple factors analysis showed that the MCAS (OR =1.899,95％ CI 1.224-2.946),history of diabetes (OR =1.764,95％ CI 1.191-2.612),systolic blood pressure(OR =1.012,95％ CI 1.003-1.022),gender (OR =0.558,95％ CI 0.380-0.821),and age (OR =1.029,95％ CI 1.010-1.049) was the independent risk factor for MCI.Conclusion The MCAS related with MCI occurrence and development.

Raman Spectral Profiles of Promoting Effects of Organic Nitrogen Sources on Ethanol Fermentation Using Saccharomyces cerevisiae / 分析化学

Nitrogen is an essential nutrient for yeast cells on ethanol fermentation. In order to reveal the promoting mechanisms of organic nitrogen sources on the ethanol fermentation by yeast, Saccharomyces cerevisiae, laser tweezers Raman spectroscopy and single-cell analysis techniques were used to monitored the kinetic of intracellular bio-macromolecules of individual cells during fermentation with urea, yeast extract, ammonium nitrate or ammonium sulfate as the sole nitrogen source. Major results from this work were as follows. (1) Organic nitrogen sources had a promoting effect on the ethanol fermentation, the fermentation with urea and yeast extract reached the maximum concentration of ethanol in 14-18 h. ( 2 ) There were no apparent lag phases for the RNA synthesis of yeast cells cultured with urea and yeast extract. The averaged Raman intensity of yeast cells at peak of 782 cm-1 in the early stage of fermentation was stronger than that of cultured with ammonium nitrate and ammonium sulfate. The maximum was about 1. 9-2. 1 times of the initial intensity for urea or yeast extract, but 1. 2-1. 4 times for ammonium nitrate and ammonium sulfate. (3) The secondary structure of proteins of partial cells cultured with yeast extract was dominated byβ-sheet, while cells cultured with other nitrogen sources were dominated by α-helix absolutely. These results bring us the conclusion that the improving effect of organic nitrogen sources such as urea and yeast extract on ethanol fermentation by Saccharomyces cerevisiae may be due to that the organic nitrogen sources can shorten the lag phase of yeast cells, promote the RNA synthesis, and promote the transcription and expression of related genes.

The correlation of mild cognitive impairment and middle cerebral artery stenosis and effect of statins on mild cognitive dysfunction / 实用医学杂志

Objective To investigate the correlation of the middle cerebral artery stenosis (MCAS) and the mild cognitive function impairment (MCI),and the clinical efficacy of statins in patients with MCI. Methods Six hundred and thirty-six patientse,who received transcranial color doppler ultrasound (TCD)assay, were enrolled in our hospital hospitalization or outpatients. The simple mental state examination (MMSE) and clinical dementia rating scale (CDR) were used as cognitive function assessment indexes. Forty-four cases of MCI with MCAS and 58 cases of MCI with NMCAS were used as the treatment group , who received the atorvastatin 20 mg every day , 56 cases of MCI with NMCAS were used as the control group , who only received the routine and basic diseases treatment. One yearlater,we determined the changes of MMSE and CDRagain. Results We detected 124 patients with MCAS, 512 patients with NMCAS, and 44 cases of MCAS patients with MCI, the prevalence was 35.5%,114 cases of NMCAS in patients with MCI, with the prevalence of 22.3%, the prevalence between the two groups was statistically different. One year later, the patients in the treatment group, MMSE score was improved, the score of MCI of the MCAS group improved more significantly. Conclusion The middle cerebral artery stenosis correlated with the occurrence of MCI. Atorvastatin could improve cognitive function in patients with MCI, especially for MCI which was caused by middle cerebral artery stenosis.