Antagonistic potential against pathogenic microorganisms and hydrogen peroxide production of indigenous lactobacilli isolated from vagina of Chinese pregnant women.

OBJECTIVE: To investigate the indigenous lactobacilli from the vagina of pregnant women and to screen the isolates with antagonistic potential against pathogenic microorganisms. METHODS: The strains were isolated from pregnant women's vagina and identified using the API50CH system. The ability of the isolates to produce hydrogen peroxide was analyzed semi-quantitatively using the TMB-HRP-MRS agar. The antagonistic effects of the isolates on pathogenic microorganisms were determined with a double layer agar plate. RESULTS: One hundred and three lactobacilli strains were isolated from 60 samples of vaginal secretion from healthy pregnant women. Among them, 78 strains could produce hydrogen peroxide, in which 68%, 80%, 80%, and 88% had antagonistic effects against Candida albicans CMCC98001, Staphylococcus aureus CMCC26003, Escherichia coli CMCC44113, and Pseudomonas aeruginosa CMCC10110, respectively. CONCLUSION: The recovery of hydrogen peroxide-producing lactobacilli decreases with the increasing pregnant age and time. The most commonly isolated species from vagina of Chinese pregnant women are Lactobacillus acidophilus and Lactobacillus crispatus. Most of L. acidophilus and L. crispatus produce a high H2O2 level.

[Improvement of two-dimensional gel electrophoresis of total proteins from rice anthers].

This paper reported an improvement in 2-D gel electrophoresis of the proteome in Honglian cytoplasmic male sterile rice. An IPGphor unit with immobile pH gradient strips was used as the first dimension and SDS-PAGE as the second. The total anther proteins were extracted using TCA/acetone and then were washed 5-6 times with acetone till the proteins were white and clean, and then tributylphosphine and DTT were added into the rehydration buffer to improve the solubility of the proteins. The 2-D gel was stained by both methods of coomassie blue G-250 and silver. Extraction of proteins, pH of the strips and rehydration of the strips were optimized and compared. Higher repeatability and better separating protein pattern could be gained by this technique.

[Preliminary proteomics analysis of the total proteins of HL Type cytoplasmic male sterility rice anther].

The proteins of HL type cytoplasmic male sterility rice anther of YTA (CMS) and YTB (maintenance line) were separated by two-dimensional electrophoresis with immobilized ph (3-10 non-linear) gradients as the first dimension and SDS-PAGE as the second. The silver-stained proteins spots were analyzed using Image Master 2D software, there were about 1800 detectable spots on each 2D-gel, and about 85 spots were differential expressed. With direct MALDI-TOF mass spectrometry analysis and protein database searching, 9 protein spots out of 16 were identified. Among those proteins, there were Putative nucleic acid binding protein, glucose-1-phosphate adenylyltransferase (ADP-glucose pyrophosphorylase, AGPase) (EC: 2.7.7.27) large chain, UDP-glucuronic acid decarboxylase, putative calcium-binding protein annexin, putative acetyl-CoA synthetase and putative lipoamide dehydrogenase etc. They were closely associated with metabolism, protein biosynthesis, transcription, signal transduction and so on, all of which are cell activities that are essential to pollen development. Some of the identified proteins, i.e. AGPase, putative lipoamide dehydrogenase and putative acetyl-CoA synthetase were deeply discussed on the relationship to CMS. AGPase catalyzes a very important step in the biosynthesis of alpha 1,4-glucans (glycogen or starch) in bacteria and plants: synthesis of the activated glucosyl donor, ADP-glucose, from glucose-1-phosphate and ATP. The lack of the AGPase in male sterile line might directly result in the reduction of starch, and the synthesis of starch was the most important processes during the development of pollen. In present research, the descent or reduction of putative lipoamide dehydrogenase and putative acetyl-CoA synthetase seemed involved in pollen sterility in rice. The degeneration and formation of various tissues during pollen development may impose high demands for energy and key biosynthetic intermediates. Under such conditions, the TCA cycle needs to operate fully, because the TCA cycle is an important source for many intermediates required for biosynthetic pathways, in addition to performing an oxidative, energy-producing role. Thus, it seemed reasonable to infer that the decrease of putative lipoamide dehydrogenase and putative acetyl-CoA synthetase in anther might prevent the conversion of pyruvate into acetyl-CoA, and as a result, the TCA cycle could no longer operate at a sufficient rate to meet all requirements in anther cells, leading to pollen sterility. This study gave new insights into the mechanism of CMS in rice and demonstrated the power of the proteomic approach in plant biology studies.

[Study on the editing sites of the coxII gene transcripts of rice mitochondria].

The term RNA editing is generally used to describe those molecular processes in which the information content is altered in an RNA molecule. This process is not limited to mRNA since alterations of non-informational RNA have also been found. RNA editing exists extensively in the higher plant mitochondria, and is the necessary step for forming functional proteins. In this paper, the research materials are the gametopthyte male sterility line (A), maintainer line (B) and F1 hybrid (F1) of HL-type CMS. 15 editing sites are found in the transcripts of coxII by comparing cDNAs and DNAs sequences. A,B and F1 have same Editing sites. When editing occurs at the first or second position of codons, the encoded amino acid is likely to be altered. As a result, the conservation of the predicted protein is improved as compared with other organisms.

[A RAPD method acceptable for the analysis of mitochondrial gene expression].

Several techniques are available in detecting variations in gene expression between different samples, such as SSH, RACE, etc. However, they can not be applied to analyze mitochondrial gene expression due to the specific characteristics of mitochondrial RNA. So some modifications were made to the conventional techniques. Here we reported a demonstration of this modified technique, taking rice mitochondria as materials. In this technique, using random hexamers to prime the RT, the resultant cDNA likely included coding regions because it was not locked to the poly(A) tail of the messenger RNA.