The binding of pefloxacin mesylate (PFLX) to bovine lactoferrin (BLf) and human serum albumin (HSA) in dilute aqueous solution was studied using fluorescence spectra and absorbance spectra. The binding constant ...The binding of pefloxacin mesylate (PFLX) to bovine lactoferrin (BLf) and human serum albumin (HSA) in dilute aqueous solution was studied using fluorescence spectra and absorbance spectra. The binding constant K and the binding sites n were obtained by fluorescence quenching method. The binding distance r and energy-transfer efficiency E between pefloxacin mesylate and bovine lactoferrin as well as human serum albumin were also obtained according to the mechanism of Forster-type dipole-dipole nonradiative energy-transfer. The effects of pefloxacin mesylate on the conformations of bovine lactoferrin and human serum albumin were also analyzed using synchronous fluorescence spectroscopy.展开更多
The dromedary camel (Camelus dromedarius) is a significant socioeconomic importance in several arid and semi-arid regions of North Africa and Middle East, and its milk constitutes an important component of human die...The dromedary camel (Camelus dromedarius) is a significant socioeconomic importance in several arid and semi-arid regions of North Africa and Middle East, and its milk constitutes an important component of human diets in these regions. The camel milk plays a vital role in the food of the Algerian nomads in the Sahara. During February and September, 20 samples of the raw camel's milk were taken starting from different livestock of camels from three different Sahariennes regions (Bechar, EI-Bayadh and Naama). These 20 collected samples were analyzed by physico-chemical and microbiological methods. The results of physicochemical analyze obtained from two hot and cold seasons are respectively the following: T ~C (35.83 and 33.95), pH (6.36 and 6.49), density (1.031 and 1.032), dornic acidity (18.6 and 18.3 ~D), dry matter (93.4 and 144.8 g/L), fat contents (30 and 52.1 g/L), total protein (26.3 and 33.1 g/L) and ashes (7.46 and 8.66 g/L). The protein profile obtained by electrophoretic analysis (SDS-PAGE) showed that camel milk contains several types of proteins and some have a molecular weight identical to major proteins of the cow's milk. The final results showed that camel milk has generally a comparable composition to that of bovine milk. The microbiological analysis, of these samples, detected a significant number of the total microflora, Staphylococcus aureus and total coliforms. The absence of Clostridium and fecal coliforms was observed. Several species of lactic acid bacteria were detected such as Lactococcus lactis subsp, lactis, Lactococcus lactis subsp, lactis biovar, diacetylactis, Weissella cibaria and Enteroccocusfeacalis.展开更多
Lactic acid bacteria (LAB) is widely used as culture starters in dairy fermentation. The aim of this study was to investigate the quality of fermented goat milk and cow milk, as well as the viability of LAB in the s...Lactic acid bacteria (LAB) is widely used as culture starters in dairy fermentation. The aim of this study was to investigate the quality of fermented goat milk and cow milk, as well as the viability of LAB in the same products. Fermentations were performed with pasteurized goat milk or cow milk added with skim milk (18% of solids) using three separately different starters; yoghurt starter (a combination of Streptococcus thermophilus FNCC-0040 and Lactobacillus bulgaricus FNCC-0041), single starter of Lactobacillus acidophilus FNCC-0029 and Lactobacillus casei FNCC-0051. The parameters observed were pH, acidity, nutritional quality including protein, fat and lactose content and product's viscosity. Acidity, pH and viability of LAB were also monitored during storage at refrigerated temperature (4 ℃) for 28 days. Results show that the different LAB starters did not affect the pH, acidity, lactose and protein content. Differences on LAB starters affected fat content and viscosity. The highest score of viscosity (30.00 Pa.s ± 7.02 Pa.s) was observed on products fermented by yoghurt starters, followed by products obtained using starter of L. acidophilus (17.7 ±11.4) and L. casei (8.62 ±0.35). Protein content, acidity, pH and viscosity were not significantly different between products obtained from goat milk and cow milk. Fat content in fermented goat milk was higher (5.03% ±0.62%) than in fermented cow milk (3.52% ±0.37%), however, lactose content was higher in fermented cow milk (5.16% ±0.40%) than in fermented goat milk (4.53% ±0.35%). Total LAB concentration in fermented cow milk during storage was 8.03± 0.52 logt0 cfu/mL, while in fermented goat milk was 7.81 loglo cfu/mL ± 0.67 loglo cfu/mL. There was a 10.83% decrease in LAB viability in fermented cow milk and 11.40% in fermented goat milk after 28 days of storage. In conclusion, quality of fermented milk is affected by the starters applied, raw milk source and storage period.展开更多
The aim of this study is to investigate the effects of leucine(Leu) and histidine(His) on the expression of both the mammalian target of rapamycin(mTOR) signaling pathway-related proteins and caseins in immortal...The aim of this study is to investigate the effects of leucine(Leu) and histidine(His) on the expression of both the mammalian target of rapamycin(mTOR) signaling pathway-related proteins and caseins in immortalized bovine mammary epithelial cells(CMEC-H), using a single supplement through Western blotting. The Earle's balanced salt solution(EBSS) was set as the control group and other treatment groups, based on the EBSS, were added with different concentrations of Leu or His, respectively. The results showed that, compared with the control group, the expression of caseins and the phosphorylation of mTOR(Ser^2481), Raptor(Ser^792), e IF4E(Ser^209), and e EF2(Thr^56) increased with the Leu concentrations ranging from 0.45 to 10.80 mmol/L(P〈0.01). The P-4EBP1(Thr^37) at 10.80 mmol/L Leu, and P-RPS6(Ser^235/236) at 5.40 to 10.80 mmol/L Leu all decreased. Similarly, the His supplementation from 0.15 to 9.60 mmol/L increased the expression of αs2-casein, β-casein, κ-casein, P-mTOR(Ser^2481), P-Raptor(Ser^792), P-S6K1(Thr^389), P-4EBP1(Thr^37), P-e IF4E(Ser^209), and P-e EF2(Thr^56)(P〈0.01) in CMEC-H, whereas the αs1-casein expression was only reduced at 9.60 mmol/L His, G protein β subunit-like protein(GβL) at 0.15 and 9.60 mmol/L His, and P-RPS6 at 4.80 to 9.60 mmol/L His. Our linear regression model assay suggested that the αs1-casein expression was positively correlated with P-mTOR(P〈0.01), P-S6K1(P〈0.01), and P-e EF2(P〈0.01) for the addition of Leu, while the expressions of β-casein(P〈0.01) and κ-casein(P〈0.01) were positively correlated with P-e EF2 for the addition of His. In conclusion, the milk protein synthesis was up-regulated through activation of the mTOR pathway with the addition of Leu and His in CMEC-H.展开更多
基金Project (No. 20173050) supported by the National Natural ScienceFoundation of China
文摘The binding of pefloxacin mesylate (PFLX) to bovine lactoferrin (BLf) and human serum albumin (HSA) in dilute aqueous solution was studied using fluorescence spectra and absorbance spectra. The binding constant K and the binding sites n were obtained by fluorescence quenching method. The binding distance r and energy-transfer efficiency E between pefloxacin mesylate and bovine lactoferrin as well as human serum albumin were also obtained according to the mechanism of Forster-type dipole-dipole nonradiative energy-transfer. The effects of pefloxacin mesylate on the conformations of bovine lactoferrin and human serum albumin were also analyzed using synchronous fluorescence spectroscopy.
文摘The dromedary camel (Camelus dromedarius) is a significant socioeconomic importance in several arid and semi-arid regions of North Africa and Middle East, and its milk constitutes an important component of human diets in these regions. The camel milk plays a vital role in the food of the Algerian nomads in the Sahara. During February and September, 20 samples of the raw camel's milk were taken starting from different livestock of camels from three different Sahariennes regions (Bechar, EI-Bayadh and Naama). These 20 collected samples were analyzed by physico-chemical and microbiological methods. The results of physicochemical analyze obtained from two hot and cold seasons are respectively the following: T ~C (35.83 and 33.95), pH (6.36 and 6.49), density (1.031 and 1.032), dornic acidity (18.6 and 18.3 ~D), dry matter (93.4 and 144.8 g/L), fat contents (30 and 52.1 g/L), total protein (26.3 and 33.1 g/L) and ashes (7.46 and 8.66 g/L). The protein profile obtained by electrophoretic analysis (SDS-PAGE) showed that camel milk contains several types of proteins and some have a molecular weight identical to major proteins of the cow's milk. The final results showed that camel milk has generally a comparable composition to that of bovine milk. The microbiological analysis, of these samples, detected a significant number of the total microflora, Staphylococcus aureus and total coliforms. The absence of Clostridium and fecal coliforms was observed. Several species of lactic acid bacteria were detected such as Lactococcus lactis subsp, lactis, Lactococcus lactis subsp, lactis biovar, diacetylactis, Weissella cibaria and Enteroccocusfeacalis.
文摘Lactic acid bacteria (LAB) is widely used as culture starters in dairy fermentation. The aim of this study was to investigate the quality of fermented goat milk and cow milk, as well as the viability of LAB in the same products. Fermentations were performed with pasteurized goat milk or cow milk added with skim milk (18% of solids) using three separately different starters; yoghurt starter (a combination of Streptococcus thermophilus FNCC-0040 and Lactobacillus bulgaricus FNCC-0041), single starter of Lactobacillus acidophilus FNCC-0029 and Lactobacillus casei FNCC-0051. The parameters observed were pH, acidity, nutritional quality including protein, fat and lactose content and product's viscosity. Acidity, pH and viability of LAB were also monitored during storage at refrigerated temperature (4 ℃) for 28 days. Results show that the different LAB starters did not affect the pH, acidity, lactose and protein content. Differences on LAB starters affected fat content and viscosity. The highest score of viscosity (30.00 Pa.s ± 7.02 Pa.s) was observed on products fermented by yoghurt starters, followed by products obtained using starter of L. acidophilus (17.7 ±11.4) and L. casei (8.62 ±0.35). Protein content, acidity, pH and viscosity were not significantly different between products obtained from goat milk and cow milk. Fat content in fermented goat milk was higher (5.03% ±0.62%) than in fermented cow milk (3.52% ±0.37%), however, lactose content was higher in fermented cow milk (5.16% ±0.40%) than in fermented goat milk (4.53% ±0.35%). Total LAB concentration in fermented cow milk during storage was 8.03± 0.52 logt0 cfu/mL, while in fermented goat milk was 7.81 loglo cfu/mL ± 0.67 loglo cfu/mL. There was a 10.83% decrease in LAB viability in fermented cow milk and 11.40% in fermented goat milk after 28 days of storage. In conclusion, quality of fermented milk is affected by the starters applied, raw milk source and storage period.
基金Project supported by the National Basic Research Program(973)of China(No.2011CB100805)the Modern Agro-Industry Technology Research System of China(No.nycytx-04-01)the Agricultural Science and Technology Innovation Program(No.ASTIP-IAS12),China
文摘The aim of this study is to investigate the effects of leucine(Leu) and histidine(His) on the expression of both the mammalian target of rapamycin(mTOR) signaling pathway-related proteins and caseins in immortalized bovine mammary epithelial cells(CMEC-H), using a single supplement through Western blotting. The Earle's balanced salt solution(EBSS) was set as the control group and other treatment groups, based on the EBSS, were added with different concentrations of Leu or His, respectively. The results showed that, compared with the control group, the expression of caseins and the phosphorylation of mTOR(Ser^2481), Raptor(Ser^792), e IF4E(Ser^209), and e EF2(Thr^56) increased with the Leu concentrations ranging from 0.45 to 10.80 mmol/L(P〈0.01). The P-4EBP1(Thr^37) at 10.80 mmol/L Leu, and P-RPS6(Ser^235/236) at 5.40 to 10.80 mmol/L Leu all decreased. Similarly, the His supplementation from 0.15 to 9.60 mmol/L increased the expression of αs2-casein, β-casein, κ-casein, P-mTOR(Ser^2481), P-Raptor(Ser^792), P-S6K1(Thr^389), P-4EBP1(Thr^37), P-e IF4E(Ser^209), and P-e EF2(Thr^56)(P〈0.01) in CMEC-H, whereas the αs1-casein expression was only reduced at 9.60 mmol/L His, G protein β subunit-like protein(GβL) at 0.15 and 9.60 mmol/L His, and P-RPS6 at 4.80 to 9.60 mmol/L His. Our linear regression model assay suggested that the αs1-casein expression was positively correlated with P-mTOR(P〈0.01), P-S6K1(P〈0.01), and P-e EF2(P〈0.01) for the addition of Leu, while the expressions of β-casein(P〈0.01) and κ-casein(P〈0.01) were positively correlated with P-e EF2 for the addition of His. In conclusion, the milk protein synthesis was up-regulated through activation of the mTOR pathway with the addition of Leu and His in CMEC-H.