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161.
渗透震扰对杜氏盐藻细胞蛋白质磷酸化的影响 总被引:3,自引:0,他引:3
杜氏盐藻(Dunalielasalina(Dunal)Teod.)细胞可溶性蛋白提取液中含有对Ca2+有一定依赖性的蛋白激酶。体内磷酸化实验进一步说明细胞质Ca2+浓度对蛋白磷酸化有影响。加入Ca2+和MoO-4显著促进低渗震扰细胞蛋白质磷酸化,而高渗震扰细胞中蛋白磷酸化程度仍低于对照;在没有Ca2+和MoO-4存在时,观察不到渗透震扰对蛋白磷酸化的刺激作用。低渗震扰信号的传导机制可能不同于高渗震扰信号,它很可能通过蛋白磷酸化进一步将信号放大,24kD蛋白是杜氏盐藻细胞蛋白激酶最有潜力的作用底物。 相似文献
162.
Ayelet Zlotogorski-Hurvitz Dan Dayan Gavriel Chaushu Johanna Korvala Tuula Salo Raija Sormunen Marilena Vered 《The journal of histochemistry and cytochemistry》2015,63(3):181-189
ExoQuick-TCTM (EQ), a chemical-based agent designed to precipitate exosomes, was calibrated for use on saliva collected from healthy individuals. The morphological and molecular features of the precipitations were compared with those obtained using the classical, physical-based method of ultracentrifugation (UC). Electron microscopy and immunoelectron microscopy with anti-CD63 showed vesicular nanoparticles surrounded by bi-layered membrane, compatible with exosomes in EQ, similar to that observed with UC. Atomic force microscopy highlighted larger, irregularly shaped/aggregated EQ nanoparticles that contrasted with the single, round-shaped UC nanoparticles. ELISA (performed on 0.5 ml of saliva) revealed a tendency for a higher expression of the specific exosomal markers (CD63, CD9, CD81) in EQ than in UC (p>0.05). ELISA for epithelial growth factor receptor, a non-exosomal-related marker, showed a significantly higher concentration in EQ than in UC (p=0.04). Western blotting of equal total-protein concentrations revealed bands of CD63, CD9 and CD81 in both types of preparations, although they were less pronounced in EQ compared with UC. This may be related to a higher fraction of non-exosomal proteins in EQ. In conclusion, EQ is suitable and efficient for precipitation of salivary exosomes from small volumes of saliva; however, EQ tends to be associated with considerably more biological impurities (non-exosomal-related proteins/microvesicles) as compared with UC. 相似文献
163.
Myzus persicae (green peach aphid) feeding on Arabidopsis thaliana induces a defence response, quantified as reduced aphid progeny production, in infested leaves but not in other parts of the plant. Similarly, infiltration of aphid saliva into Arabidopsis leaves causes only a local increase in aphid resistance. Further characterization of the defence-eliciting salivary components indicates that Arabidopsis recognizes a proteinaceous elicitor with a size between 3 and 10 kD. Genetic analysis using well-characterized Arabidopsis mutants shows that saliva-induced resistance against M. persicae is independent of the known defence signalling pathways involving salicylic acid, jasmonate and ethylene. Among 78 Arabidopsis genes that were induced by aphid saliva infiltration, 52 had been identified previously as aphid-induced, but few are responsive to the well-known plant defence signalling molecules salicylic acid and jasmonate. Quantitative PCR analyses confirm expression of saliva-induced genes. In particular, expression of a set of O -methyltransferases, which may be involved in the synthesis of aphid-repellent glucosinolates, was significantly up-regulated by both M. persicae feeding and treatment with aphid saliva. However, this did not correlate with increased production of 4-methoxyindol-3-ylmethylglucosinolate, suggesting that aphid salivary components trigger an Arabidopsis defence response that is independent of this aphid-deterrent glucosinolate. 相似文献
164.
Summary We demonstrate that the high affinity bumetanide binding site of the rabbit parotid acinar cell can be extracted from a basolateral membrane fraction using relatively low concentrations (0.07%, wt/vol; 1 mg membrane protein/ml) of the nonionic detergent Triton X-100. This extracted site cannot be sedimented by ultracentrifugation at 100,000 ×g × 1 hr. Bumetanide binding to this site retains the ionic characteristics of bumetanide binding to native membranes but shows a fivefold increase in binding affinity (K
d=0.57±0.15 m
vs.K
d=3.3±0.7 m for native membranes). Inactivation of the extracted bumetanide binding site observed at detergent/protein ratios>1 can be prevented or (partially) reversed by the addition of exogenous lipid (0.2% soybean phosphatidylcholine). When the 0.07% Triton extract is fractionated by sucrose density gradient centrifugation in 0.24% Triton X-100, 0.2% exogenous lipid and 200mm salt, the high affinity bumetanide binding site sediments as a single band withS
20,w
=8.8±0.8 S. This corresponds to a molecular weight 200 kDa for the bumetanide binding protein-detergent-lipid complex and represents a sevenfold purification of this site relative to the starting membrane fraction. In contrast to previous attempts to purify Na/K/Cl cotransport proteins and their associated bumetanide binding sites, the present method avoids harsh detergent treatment as well as direct covalent modification (inactivation) of the transporter itself. As a consequence, one can follow the still active protein through a series of extraction and purification steps by directly monitoring its bumetanide binding properties. 相似文献
165.
Salivary nitrate is reduced to nitric oxide (NO) via nitrite in the human oral cavity. The nitrite and NO formed can be transformed to reactive nitrogen oxide species (RNOS). In this investigation, RNOS formed in mixed whole saliva and its fractions were detected by the oxidation of aminophenyl fluorescein (APF) and the transformation of 3-amino-4-monomethylamino-2',7'-difluorofluorecein (DAF-FM) to its triazol form (DAF-FMT). Nitrite-induced oxidation of APF and formation of DAF-FMT increased as pH was decreased from 7 to 5 and SCN- inhibited the oxidation of APF and the formation of DAF-FMT around neutral pH and enhanced at pH about 5. The SCN--dependent inhibition was due to the suppression of salivary peroxidase and the enhancement was due to the formation of NOSCN from HNO2 and SCN-. It is deduced that the increase in the concentrations of nitrite and H+ in the oral cavity may result in the enhanced formation of RNOS. 相似文献
166.
167.
Tomoko Nashida Sumio Yoshie Hiromi Shimomura 《Archives of biochemistry and biophysics》2009,487(2):131-48
Transferrin is the major iron transporter in blood plasma, and is also found, at lower concentrations, in saliva. We studied the synthesis and secretion of transferrin in rat parotid acinar cells in order to elucidate its secretory pathways. Two sources were identified for transferrin in parotid acinar cells: synthesis by the cells (endogenous), and absorption from blood plasma (exogenous). Transferrin from both sources is secreted from the apical side of parotid acinar cells. Endogenous transferrin is transported to secretory granules. It is secreted from mature secretory granules upon stimulation with a β-adrenergic reagent and from smaller vesicles in the absence of stimulation. Exogenous transferrin is internalized from the basolateral side of parotid acinar cells, transported to the apical side by transcytosis, and secreted from the apical side. Secretory processes for exogenous transferrin include transport systems involving microfilaments and microtubules. 相似文献
168.
Dallas M. Cowan Qiyuan Fan Yan Zou Xiujuan Shi Jian Chen Michael Aschner 《Biomarkers》2013,18(1):3-16
Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population. 相似文献
169.
Timothy Lockwich Lawrence M. Mertz Indu S. Ambudkar 《Molecular and cellular biochemistry》1993,126(2):143-150
Divalent cation permeability of rat parotid gland basolateral plasma membranes was examined in dispersed parotid acini (by Ca2+ or Mn2+ entry) and in isolated basolateral plasma membrane vesicles (BLMV, by45Ca2+ influx). Mn2+ entry (fura2 quenching) was about 1.6 fold higher in internal Ca2+ pool-depleted acini (Ca2+-depl acini) than in unstimulated cells. Mn2+ entry into Ca2+-depl acini was increased at external pH>7.4 and decreased at pH<7.4. Pretreatment of Ca2+-depl acini with the relatively hydrophobic carboxylic group reagent, N,N-dicyclohexylcarbodiimide (DCCD, 50 M for 30 min) resulted in the inhibition of Mn2+ entry into Ca2+-depl acini to unstimulated levels. Another hydrophobic carboxyl group reagent, N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) and the relatively hydrophilic carboxyl group reagents, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide (CMCD) did not affect Mn2+ entry.Similar to the effects in intact acini, Ca2+ influx into BLMV was decreased when the external pH was lowered below 7.4. Also DCCD (5 mM, 30 min), but not EEDQ, decreased (40%) Ca2+ influx in BLMV. However, unlike in acini, the hydrophilic reagents, EDC, EAC, and CMCD decreased Ca2+ permeability in BLMV and the effects were nonadditive with the decrease induced by DCCD. The aggregate effects of carboxyl group reagents on the Ca2+ and Mn2+ permeability in BLMV and intact acini, respectively, suggest that a critical carboxyl group (most likely accessible from the cytoplasmic side of the plasma membrane) is involved in divalent cation flux in rat parotid acinar cells. 相似文献
170.
A calcium dependent apyrase activity (ATP→AMP + 2Pi) has been characterized in the salivary secretion of Rhodnius prolixus. High levels of this activity were found in the crop of all stages of larvae and the adults after a single blood or saline meal. The activity persisted for several days but was totally absent in the crop insects from which the salivary glands had been removed. The use of this activity as a saliva marker shows that the insect salivates during the whole meal and most of the saliva is ingested with the food. The physiological role of this activity is discussed. A simple method for saliva collection and a technique for the surgical ablation of the salivary glands in adult insects are described. 相似文献