μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postm...μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postmortem aging were studied. The results showed that delay chilling significantly improved μ-calpain activities (P<0.05) and enhanced the tenderness of bovine M. longissimus during earlier aging periods compared with conventional chilling. But in later aging periods,delay chilling weakened the effect on the tenderness of beef because of premature consumption of μ-calpain. The experiment results confirmed that delay chilling improved the rate of postmortem aging of beef and remarkably enhanced the tenderness of beef through the effect of delay chilling on μ-calpain activities.展开更多
The objectives of the study were: a) to determine the optimal concentration of the extract that should be incorporated in meat products to maintain the lipid oxidative stability, and b) to verify if the extract exe...The objectives of the study were: a) to determine the optimal concentration of the extract that should be incorporated in meat products to maintain the lipid oxidative stability, and b) to verify if the extract exerted antioxidant activity even when these products were enriched with soybean oil (with fatty acids omega 3). To carry out these aims, in the first instance the additive was incorporated into meat patties (elaborated with 80% beef and 20% fat plus 2% salt over total mass) at 0, 0.5, 1, 5 and 10 g/kg, respectively. The lipid oxidation was evaluated by measurement of peroxide value during 15 days at 8 ℃ and the results were expressed as reduction percentage of peroxidation (RP). RP obtained were 55, 49, 73 and 59 respectively. As 5 g/kg was the optimum concentration of antioxidant, this was chosen to add to meat products enriched with soybean oil. In this case the RP obtained was 78%, indicating that the extract decreased lipid oxidation effectively.展开更多
Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were (i) to analyze a...Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were (i) to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and (ii) to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients (nitrate,ammonium,phosphorus,potassium,calcium and magnesium),total nitrogen,organic carbon and pH were measured. Plant chemical contents (protein,lignin and others) were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers. Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrient concentration into the centre of the camping area reduced floral composition again. To ensure positive effects of camping areas on plant diversity,and to manage more effectively the nutrients returned to the soil,a reduction in the stocking rate should be pursued.展开更多
In acid precipitation area of Chongqing suburb the average of Hg in soil rose from 0.158 mg/kg in 1984to 0.20 mg/kg in 1989, and Hg content of crops grown on these soils increased too. Both soil and vegetableHg came m...In acid precipitation area of Chongqing suburb the average of Hg in soil rose from 0.158 mg/kg in 1984to 0.20 mg/kg in 1989, and Hg content of crops grown on these soils increased too. Both soil and vegetableHg came mainly from power plant emission, which caused Hg and acid precipitation pollution in environmentand the Hg pollution of water, crops and milk in the area.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
This study was concerned on the influence of cooking liquor parameters i.e. active alkali (AA) and sulfidity, on the properties of pulp produced from Thai bamboo by means of multivariate analysis. The investigated p...This study was concerned on the influence of cooking liquor parameters i.e. active alkali (AA) and sulfidity, on the properties of pulp produced from Thai bamboo by means of multivariate analysis. The investigated pulp properties were cooking yield and viscosity. The experiments were performed according to a face centered cube experimental design. Then, multiple linear regression (MLR) of independent and dependent variables were conducted with SPSS software using least square method. In order to optimize process, Pareto-Optimality method was employed. The obtained regression models were characterized by both descriptive and predictive ability (R^2 ≥ 95% and Rcv^2 ≥ 93%) and allowed the kraft pulping process with an acceptable viscosity ( 1110- 1 190 ml/g) and a total yield about 50% at a sulfidity level of 20-30% with 18% AA. Results indicated that high sulfidity at a lower AA could get high viscosity and relatively low kappa number for pulps. Also oxygen delignification was studied in this research.展开更多
The present study was conducted in four districts of Telangana State of India with 120 respondents in which 60 were members and other 60 were non-members of DCSs (Dairy Co-operative Societies)/MPIs (Milk Producer I...The present study was conducted in four districts of Telangana State of India with 120 respondents in which 60 were members and other 60 were non-members of DCSs (Dairy Co-operative Societies)/MPIs (Milk Producer Institutions). Constraints perceived in dairy farming and suggestions elicited by members and non-members were noted, tabulated and analyzed. The major constraints perceived by half or more than half of members were scarcity of water (91.67%), lack of green fodder (88.33%), preferring NS (natural service) than AI (Artificial Insemination) (83.33%), negligence in feeding pregnant and dry animals (81.37%), insufficient loan amount (78.33%), tendency to feed only grass and brans (71.67%), lack of availability of sufficient labour (70.00%), lack of remunerative price for milk (66.67%), high cost of feed (61.67%), lack of fodder conservation (55.00%) and high cost of animals (50.00%). Whereas major constraints perceived by non-members were scarcity of water (96.67%), lack of green fodder (93.33%), preferring NS than AI (88.33%), lack of availability of sufficient labour (85.00%), negligence in feeding pregnant and dry animals (83.33%), tendency to feed only grass and brans (78.33%), high cost of animals (75.00%), complex procedure for obtaining loans (71.67%) and high cost of feed (66.67%). Suggestions elicited by members majorly were providing subsidy for purchase of animals/providing loans on par with the cost of animal (81.67%), enhancing the procurement price (70.00%), providing more incentives (60.00%), encouraging calf rearing (58.33%) and conducting frequent animal health camps (50.00%). In case of non-members major suggestions elicited were conducting frequent animal health camps (68.33%) and providing subsidy on purchase of animals/providing loans on par with the cost of animal (58.33%). Considering the above constraints perceived and suggestions elicited by dairy farmers a proper linkage strategy should be developed among private and public sectors in providing need based services to the dairy farmers.展开更多
On the Kpinnou ranch in Benin, it was observed that the Girolando dairy cattle which graze Panieum maximum var. CI are more susceptible to infestation of ticks. The purpose of this study was to highlight the interacti...On the Kpinnou ranch in Benin, it was observed that the Girolando dairy cattle which graze Panieum maximum var. CI are more susceptible to infestation of ticks. The purpose of this study was to highlight the interactions between ticks and their bovine hosts and two types of artificial grazing pastures. Nineteen young Girolando dairy cattle were used during the big rainy season (March-June) 2009. All present ticks on the animals have been counted according to the body region. The bovine have been divided into two relatively homogeneous groups often and nine animals. The group I of 10 animals had been grazed on Panicum maximum whereas the group 2 of 9 animals had been grazed on Panicum maximum var. C 1. During the two months of grazing, a weekly monitoring of the evolution of the load in ticks has been achieved. Four genera of ticks were identified on the bovine Girolandos (Amblyomma, Hyalomma, Rhipicephalus and Boophilus). The Boophilus genus is the most abundant (P 〈 0.05). The animals having grazed Panicum maximum var. C I are more infested than those that have been grazed Panicum maximum. A variation of the rate of infestation of the animals has been observed in relation to the different body areas. The colour of the coat also has an effect on the load in tick of the bovine. The bovine of dark coat are in general more infested (P 〈 0.05) than those of clear colour.展开更多
Economic impact of climate extremes on beef operation is expected to be significant due to its direct impact on feed production. Impact of such events on farm management and longer term farm financial situation is rel...Economic impact of climate extremes on beef operation is expected to be significant due to its direct impact on feed production. Impact of such events on farm management and longer term farm financial situation is relatively unstudied in the Canadian Prairie. This study compared three alternative beef herd management strategies in dealing with climate extreme events under reference climate scenario of 1971-2000 and the future scenario of 2041-2070. The study used farm simulation model that integrated the model of cattle herd simulation, pasture model, crop simulation model combined with models of economic decisions. Purchasing feed and maintaining herd size is preferred option in dealing with drought Changes in management such as early weaning combined with limit feeding strategies reduce the feed demand and also reduce the financial burden during the years of extreme event, but it has severe negative consequences on amount of slaughter cattle sold. Cull herd strategy not only reduces feed demand but also increases income from sell of herd during the year/s of extreme event, but it severely impacts the farm's long term output supply potential. However, expansion of existing agriculture risk management policy to cover climate risk in beef production is necessary to support farmers in the year/s to extreme events.展开更多
A thorough understanding of how proteins induce nanoparticle (NP) aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developi...A thorough understanding of how proteins induce nanoparticle (NP) aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developing nano-applications and formulation for drug delivery systems. In this study, we found that extraction of immunoglobulin G (IgG) from cow serum results in lower polystyrene NPs aggregation. Moreover, addition of isolated IgG or fibrinogen to fetal cow serum enhanced this aggregation, thus demonstrating that these factors are major drivers of NP aggregation in serum. Counter-intuitively, NP aggregation was inversely dependent on protein concentration; i.e., low protein concentrations induced large aggregates, whereas high protein concentrations induced small aggregates. Protein-induced NP aggregation and aggregate size were monitored by absorbance at 400 nm and dynamic light scattering, respectively. Here, we propose a mechanism behind the protein concentration dependent aggregation; this mechanism involves the effects of multiple protein interactions on the NP surface, surface area limitations, aggregation kinetics, and the influence of other serum proteins.展开更多
Baicalein, baicalin, scutellarin and Chrysin-7-O-β-D-glucuronide are the major flavonoids of the Shuang-huang-lian powder injection. These flavonoids are thought to be haptens that can induce allergic reactions. The ...Baicalein, baicalin, scutellarin and Chrysin-7-O-β-D-glucuronide are the major flavonoids of the Shuang-huang-lian powder injection. These flavonoids are thought to be haptens that can induce allergic reactions. The interaction mechanism of these haptens with bovine serum albumin (BSA) was investigated by surface plasmon resonance (SPR) and molecular modeling method. The SPR study indicated that these compounds could specifically bind to the BSA with one binding site and equilibrium dissociation constant (KD) values were determined. Molecular modeling explored the mechanism of interaction under simulated physiological condition. The result of molecular modeling indicated that flavonoids could bind with BSA in the hydrophobic pocket of sub-domain II with hydrogen bonding as the main acting force.展开更多
The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were hi...The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable.The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ.The quenching was static quenching,epicatechin had a weak interaction with BSA and the binding site was one.The total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions,avoiding complicated pretreatment and simplify experimental procedure.展开更多
The interaction between 3-thiol-4-(2,4-dichlorobenzylideneamino)-5-methyl-4H-1,2,4-triazole (CBTZ) and bovine serum albumin (BSA) under physiological conditions was investigated by fluorescence,UV-vis absorption and c...The interaction between 3-thiol-4-(2,4-dichlorobenzylideneamino)-5-methyl-4H-1,2,4-triazole (CBTZ) and bovine serum albumin (BSA) under physiological conditions was investigated by fluorescence,UV-vis absorption and circular dichroism (CD) spectroscopy as well as molecular modeling methods. The result of fluorescence experiment indicates the static quenching as a result of the formation of the CBTZ-BSA complex. The binding constants (Ka) at different temperatures were calculated according to the modified Stern-Volmer equation. The enthalpy change (-H) and entropy change (-S) were determined based on the van′t Hoff equation. Both negative-H and-S indicated that van der Waals and hydrogen-bonding forces were the dominant intermolecular forces to stabilize the CBTZ-BSA complex. Site marker competitive replacement experiments demonstrated that binding of CBTZ to BSA primarily took place in sub-domain IIA (Sudlow's site I). The binding distance (r = 7.2 nm) between CBTZ and the tryptophan residue of BSA was estimated according to the theory of fluorescence resonance energy transfer (FRET). The conformational studies by circular dichroism (CD) and three-dimensional fluorescence spectroscopy showed that the presence of CBTZ induced minor changes of the secondary structure of BSA. Molecular modeling study further confirmed the binding mode obtained experimentally.展开更多
基金Supported by the National High Technology Research and Development Program of China(2006BAD05A03)~~
文摘μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postmortem aging were studied. The results showed that delay chilling significantly improved μ-calpain activities (P<0.05) and enhanced the tenderness of bovine M. longissimus during earlier aging periods compared with conventional chilling. But in later aging periods,delay chilling weakened the effect on the tenderness of beef because of premature consumption of μ-calpain. The experiment results confirmed that delay chilling improved the rate of postmortem aging of beef and remarkably enhanced the tenderness of beef through the effect of delay chilling on μ-calpain activities.
文摘The objectives of the study were: a) to determine the optimal concentration of the extract that should be incorporated in meat products to maintain the lipid oxidative stability, and b) to verify if the extract exerted antioxidant activity even when these products were enriched with soybean oil (with fatty acids omega 3). To carry out these aims, in the first instance the additive was incorporated into meat patties (elaborated with 80% beef and 20% fat plus 2% salt over total mass) at 0, 0.5, 1, 5 and 10 g/kg, respectively. The lipid oxidation was evaluated by measurement of peroxide value during 15 days at 8 ℃ and the results were expressed as reduction percentage of peroxidation (RP). RP obtained were 55, 49, 73 and 59 respectively. As 5 g/kg was the optimum concentration of antioxidant, this was chosen to add to meat products enriched with soybean oil. In this case the RP obtained was 78%, indicating that the extract decreased lipid oxidation effectively.
文摘Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were (i) to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and (ii) to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients (nitrate,ammonium,phosphorus,potassium,calcium and magnesium),total nitrogen,organic carbon and pH were measured. Plant chemical contents (protein,lignin and others) were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers. Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrient concentration into the centre of the camping area reduced floral composition again. To ensure positive effects of camping areas on plant diversity,and to manage more effectively the nutrients returned to the soil,a reduction in the stocking rate should be pursued.
文摘In acid precipitation area of Chongqing suburb the average of Hg in soil rose from 0.158 mg/kg in 1984to 0.20 mg/kg in 1989, and Hg content of crops grown on these soils increased too. Both soil and vegetableHg came mainly from power plant emission, which caused Hg and acid precipitation pollution in environmentand the Hg pollution of water, crops and milk in the area.
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.
文摘This study was concerned on the influence of cooking liquor parameters i.e. active alkali (AA) and sulfidity, on the properties of pulp produced from Thai bamboo by means of multivariate analysis. The investigated pulp properties were cooking yield and viscosity. The experiments were performed according to a face centered cube experimental design. Then, multiple linear regression (MLR) of independent and dependent variables were conducted with SPSS software using least square method. In order to optimize process, Pareto-Optimality method was employed. The obtained regression models were characterized by both descriptive and predictive ability (R^2 ≥ 95% and Rcv^2 ≥ 93%) and allowed the kraft pulping process with an acceptable viscosity ( 1110- 1 190 ml/g) and a total yield about 50% at a sulfidity level of 20-30% with 18% AA. Results indicated that high sulfidity at a lower AA could get high viscosity and relatively low kappa number for pulps. Also oxygen delignification was studied in this research.
文摘The present study was conducted in four districts of Telangana State of India with 120 respondents in which 60 were members and other 60 were non-members of DCSs (Dairy Co-operative Societies)/MPIs (Milk Producer Institutions). Constraints perceived in dairy farming and suggestions elicited by members and non-members were noted, tabulated and analyzed. The major constraints perceived by half or more than half of members were scarcity of water (91.67%), lack of green fodder (88.33%), preferring NS (natural service) than AI (Artificial Insemination) (83.33%), negligence in feeding pregnant and dry animals (81.37%), insufficient loan amount (78.33%), tendency to feed only grass and brans (71.67%), lack of availability of sufficient labour (70.00%), lack of remunerative price for milk (66.67%), high cost of feed (61.67%), lack of fodder conservation (55.00%) and high cost of animals (50.00%). Whereas major constraints perceived by non-members were scarcity of water (96.67%), lack of green fodder (93.33%), preferring NS than AI (88.33%), lack of availability of sufficient labour (85.00%), negligence in feeding pregnant and dry animals (83.33%), tendency to feed only grass and brans (78.33%), high cost of animals (75.00%), complex procedure for obtaining loans (71.67%) and high cost of feed (66.67%). Suggestions elicited by members majorly were providing subsidy for purchase of animals/providing loans on par with the cost of animal (81.67%), enhancing the procurement price (70.00%), providing more incentives (60.00%), encouraging calf rearing (58.33%) and conducting frequent animal health camps (50.00%). In case of non-members major suggestions elicited were conducting frequent animal health camps (68.33%) and providing subsidy on purchase of animals/providing loans on par with the cost of animal (58.33%). Considering the above constraints perceived and suggestions elicited by dairy farmers a proper linkage strategy should be developed among private and public sectors in providing need based services to the dairy farmers.
文摘On the Kpinnou ranch in Benin, it was observed that the Girolando dairy cattle which graze Panieum maximum var. CI are more susceptible to infestation of ticks. The purpose of this study was to highlight the interactions between ticks and their bovine hosts and two types of artificial grazing pastures. Nineteen young Girolando dairy cattle were used during the big rainy season (March-June) 2009. All present ticks on the animals have been counted according to the body region. The bovine have been divided into two relatively homogeneous groups often and nine animals. The group I of 10 animals had been grazed on Panicum maximum whereas the group 2 of 9 animals had been grazed on Panicum maximum var. C 1. During the two months of grazing, a weekly monitoring of the evolution of the load in ticks has been achieved. Four genera of ticks were identified on the bovine Girolandos (Amblyomma, Hyalomma, Rhipicephalus and Boophilus). The Boophilus genus is the most abundant (P 〈 0.05). The animals having grazed Panicum maximum var. C I are more infested than those that have been grazed Panicum maximum. A variation of the rate of infestation of the animals has been observed in relation to the different body areas. The colour of the coat also has an effect on the load in tick of the bovine. The bovine of dark coat are in general more infested (P 〈 0.05) than those of clear colour.
文摘Economic impact of climate extremes on beef operation is expected to be significant due to its direct impact on feed production. Impact of such events on farm management and longer term farm financial situation is relatively unstudied in the Canadian Prairie. This study compared three alternative beef herd management strategies in dealing with climate extreme events under reference climate scenario of 1971-2000 and the future scenario of 2041-2070. The study used farm simulation model that integrated the model of cattle herd simulation, pasture model, crop simulation model combined with models of economic decisions. Purchasing feed and maintaining herd size is preferred option in dealing with drought Changes in management such as early weaning combined with limit feeding strategies reduce the feed demand and also reduce the financial burden during the years of extreme event, but it has severe negative consequences on amount of slaughter cattle sold. Cull herd strategy not only reduces feed demand but also increases income from sell of herd during the year/s of extreme event, but it severely impacts the farm's long term output supply potential. However, expansion of existing agriculture risk management policy to cover climate risk in beef production is necessary to support farmers in the year/s to extreme events.
文摘A thorough understanding of how proteins induce nanoparticle (NP) aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developing nano-applications and formulation for drug delivery systems. In this study, we found that extraction of immunoglobulin G (IgG) from cow serum results in lower polystyrene NPs aggregation. Moreover, addition of isolated IgG or fibrinogen to fetal cow serum enhanced this aggregation, thus demonstrating that these factors are major drivers of NP aggregation in serum. Counter-intuitively, NP aggregation was inversely dependent on protein concentration; i.e., low protein concentrations induced large aggregates, whereas high protein concentrations induced small aggregates. Protein-induced NP aggregation and aggregate size were monitored by absorbance at 400 nm and dynamic light scattering, respectively. Here, we propose a mechanism behind the protein concentration dependent aggregation; this mechanism involves the effects of multiple protein interactions on the NP surface, surface area limitations, aggregation kinetics, and the influence of other serum proteins.
基金Nature Science Foundation of Beijing,China(Grant No.7142088)
文摘Baicalein, baicalin, scutellarin and Chrysin-7-O-β-D-glucuronide are the major flavonoids of the Shuang-huang-lian powder injection. These flavonoids are thought to be haptens that can induce allergic reactions. The interaction mechanism of these haptens with bovine serum albumin (BSA) was investigated by surface plasmon resonance (SPR) and molecular modeling method. The SPR study indicated that these compounds could specifically bind to the BSA with one binding site and equilibrium dissociation constant (KD) values were determined. Molecular modeling explored the mechanism of interaction under simulated physiological condition. The result of molecular modeling indicated that flavonoids could bind with BSA in the hydrophobic pocket of sub-domain II with hydrogen bonding as the main acting force.
基金financially supported by the National Natural Science Foundation of China(21175041)the National Basic Research Program of China(2012CB910602)
文摘The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable.The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ.The quenching was static quenching,epicatechin had a weak interaction with BSA and the binding site was one.The total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions,avoiding complicated pretreatment and simplify experimental procedure.
基金supported by the National Natural Science Foundation of China (20873096, 20921062 and 20621502)Fundamental Research Funds for Central Universities (1101007)
文摘The interaction between 3-thiol-4-(2,4-dichlorobenzylideneamino)-5-methyl-4H-1,2,4-triazole (CBTZ) and bovine serum albumin (BSA) under physiological conditions was investigated by fluorescence,UV-vis absorption and circular dichroism (CD) spectroscopy as well as molecular modeling methods. The result of fluorescence experiment indicates the static quenching as a result of the formation of the CBTZ-BSA complex. The binding constants (Ka) at different temperatures were calculated according to the modified Stern-Volmer equation. The enthalpy change (-H) and entropy change (-S) were determined based on the van′t Hoff equation. Both negative-H and-S indicated that van der Waals and hydrogen-bonding forces were the dominant intermolecular forces to stabilize the CBTZ-BSA complex. Site marker competitive replacement experiments demonstrated that binding of CBTZ to BSA primarily took place in sub-domain IIA (Sudlow's site I). The binding distance (r = 7.2 nm) between CBTZ and the tryptophan residue of BSA was estimated according to the theory of fluorescence resonance energy transfer (FRET). The conformational studies by circular dichroism (CD) and three-dimensional fluorescence spectroscopy showed that the presence of CBTZ induced minor changes of the secondary structure of BSA. Molecular modeling study further confirmed the binding mode obtained experimentally.