Proteome characterization of cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz) somatic embryos,plantlets and tuberous roots

Background  

Proteomics is increasingly becoming an important tool for the study of many different aspects of plant functions, such as investigating the molecular processes underlying in plant physiology, development, differentiation and their interaction with the environments. To investigate the cassava (Manihot esculenta Crantz) proteome, we extracted proteins from somatic embryos, plantlets and tuberous roots of cultivar SC8 and separated them by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).     

多头绒泡菌核仁及其骨架中原肌球蛋白的免疫细胞化学鉴定

分离多头绒泡菌(physarum polycephalum)细胞的核仁,先用Dnase I消化,去除核仁内的DNA;然后用025mol/L (NH4)2ＳＯ４和2mol/L NaCl相继抽提去掉大部分蛋白质,制备成核仁骨架。SDSPAGE分析结果表明,核仁骨架中含有约20种多肽,其中包括37kD左右与原肌球蛋白分子量相当的多肽。以兔抗原肌球蛋白抗体为一抗,FITC标记的羊抗兔IgG抗体为二抗的间接免疫荧光检测结果表明,核仁和核仁骨架样品都能发出明亮的荧光,而对照样品未见明亮的荧光。间接免疫斑点印迹检测结果进一步证明,在核仁骨架的蛋白质成分中存在原肌球蛋白。胶体金免疫电镜检测结果显示,标记原肌球蛋白抗体的标本上有较多的金颗粒,而对照组标本上只有极少的金颗粒。金颗粒在核仁中主要呈散在分布。     

pH-induced conformational changes in the soluble manganese-stabilizing protein of photosystem II

In this paper, we analyzed the pH-induced changes in the conformational states of the manganese-stabilizing protein (MSP) of photosystem II. Distinct conformational states of MSP were identified using fluorescence spectra, far-UV circular dichroism, and pressure-induced unfolding at varying suspension pH values, and four different conformational states of MSP were clearly distinguished using the center of fluorescence spectra mass when suspension pH was altered from 2 to 12. MSP was completely unfolded at a suspension pH above 11 and partly unfolded below a pH of 3. Analysis of the center of fluorescence spectral mass showed that the MSP structure appears stably folded around pH 6 and 4. The conformational state of MSP at pH 4 seems more stable than that at pH 6. Studies of peak positions of tryptophan fluorescence and MSP-bound 1-anilinonaphthalene-8-sulfonic acid fluorescence spectra supported this observation. A decrease in the suspension pH to 2 resulted in significant alterations in the MSP structure possibly because of protonation of unprotonated residues at lower pH, suggesting the existence of a large number of unprotonated amino acid residues at neutral pH possibly useful for proton transport in oxygen evolution. The acidic pH-induced conformational changes of MSP were reversible upon increase of pH to neutral pH; however, N-bromosuccinimide modification of tryptophan (Trp241) blocks the recovery of pH-induced conformational changes in MSP, implying that Trp241 is a key residue for the unfolded protein to form a functional structure. Thus, pH-induced structural changes of stable MSP (pH 6-4) may be utilized to analyze its functionality as a cofactor for oxygen evolution.     

Assessment of genetic stability of the germplasm lines of medicinal plant <Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi (Huang-qin) in long-term,in vitro maintained cultures

An approach of combining flow cytometry (FCM) analysis with morphological and chemical profiling was used to assess the genetic stability and bioactive compound diversity in a Scutellaria baicalensis Georgi (Huang-qin) germplasm collection that was clonally maintained in in vitro for a period of over 6 years. Based on the FCM analysis of nuclei samples from young shoots, the nuclear DNA content of S. baicalensis was calculated as 0.84 pg/2C. FCM analysis showed no significant variation in the nuclear DNA contents and ploidy levels in the long-term in vitro maintained germplasm lines. Germplasm lines, acclimatized to ex vitro conditions, exhibited distinctive plant growth and bioactive compound production capacities. The high level of genetic stability observed in in vitro maintained S. baicalensis lines opens up a variety of opportunities such as allowing long-term aseptic preservation and easy distribution of well-characterized germplasm lines of this medicinal plant species. This study represents a novel approach for continuous maintenance, monitoring, and production of medicinal plant tissues with specific chemistry.     

Effect of nitrite from nitritation on biological phosphorus removal in a sequencing batch reactor treating domestic wastewater

Although nitrite effect on enhanced biological phosphorus removal (EBPR) has been previously studied, very limited research has been undertaken about the effect of nitrite accumulation caused by nitritation on EBPR. This paper focused on nitrite effect from nitritation on EBPR in a sequencing batch reactor treating domestic wastewater. Results showed that nitrite of below 10 mg/L did not inhibit P-uptake and release; whereas EBPR deterioration was observed when nitrite accumulation reached 20 mg/L. Due to P-uptake prior to nitritation, nitrite of 20 mg/L has no effect on aerobic P-uptake. The main reason leading to EBPR deterioration was the competition of carbon source. Batch tests were conducted to investigate nitrite effect on anaerobic P-release. Under sufficient carbon source, nitrite of 30 mg/L had no impact on poly-β-hydroxyalkanoate (PHA) storage; contrarily, under insufficient carbon source, denitrifiers competing for carbon source with phosphorus accumulating organisms resulted in decrease of PHA synthesis and P-release.     

Combined effect of sodium dodecyl sulfate and enzyme on waste activated sludge hydrolysis and acidification

The combined effect of sodium dodecyl sulfate (SDS) and enzyme system on hydrolysis and acidification of waste activated sludge (WAS) was investigated. The results showed that the combined system was more effective in the promotion of sludge hydrolysis than sole SDS and sole enzyme, and the SDS + mixed-enzymes (ME) system had better hydrolysis performance than SDS + single enzyme system. Compared with SDS + protease and SDS + amylase systems, the soluble protein concentration in SDS + ME system increased respectively by 20.0% and 44.4%, and the soluble carbohydrate concentration increased by 78.3% and 37.0%, respectively. During the WAS acidification stage, the SDS, ME and SDS + ME system could make the maximum short-chain fatty acids (SCFAs) concentration increased by 1.82 (6th day), 2.04 (5th day), 2.32 (7th day) times, respectively. The composition analysis of SCFAs produced in SDS + ME system indicated that acetic acid was the most prevalent product and propionic acid was the second one.     

Proteomic analysis of silk gland programmed cell death during metamorphosis of the silkworm Bombyx mori

The silk gland of the silkworm Bombyx mori undergoes programmed cell death (PCD) during pupal metamorphosis. On the basis of their morphological changes and the occurrence of a DNA ladder, the tissue cells were categorized into three groups: intact, committed, and dying. To identify the proteins involved in this process, we conducted a comparative proteomic analysis. Protein expression changes among the three different cell types were examined by two-dimensional gel electrophoresis. Among approximately 1000 reproducibly detected protein spots on each gel, 43 were down-regulated and 34 were up-regulated in PCD process. Mass spectrometry identified 17 differentially expressed proteins, including some well-studied proteins as well as some novel PCD related proteins, such as caspases, proteasome subunit, elongation factor, heat shock protein, and hypothetical proteins. Our results suggest that these proteins may participate in the silk gland PCD process of B. mori and, thus, provide new insights for this mechanism.     

NF-kappaB in breast cancer cells promotes osteolytic bone metastasis by inducing osteoclastogenesis via GM-CSF

Advanced breast cancers frequently metastasize to bone, resulting in osteolytic lesions, yet the underlying mechanisms are poorly understood. Here we report that nuclear factor-kappaB (NF-kappaB) plays a crucial role in the osteolytic bone metastasis of breast cancer by stimulating osteoclastogenesis. Using an in vivo bone metastasis model, we found that constitutive NF-kappaB activity in breast cancer cells is crucial for the bone resorption characteristic of osteolytic bone metastasis. We identified the gene encoding granulocyte macrophage-colony stimulating factor (GM-CSF) as a key target of NF-kappaB and found that it mediates osteolytic bone metastasis of breast cancer by stimulating osteoclast development. Moreover, we observed that the expression of GM-CSF correlated with NF-kappaB activation in bone-metastatic tumor tissues from individuals with breast cancer. These results uncover a new and specific role of NF-kappaB in osteolytic bone metastasis through GM-CSF induction, suggesting that NF-kappaB is a potential target for the treatment of breast cancer and the prevention of skeletal metastasis.