AIM:To compare the effects of four Bifidobacteria strains(Bifidobacteria L66-5,L75-4,M13-4 and FS31-12,originated from normal human intestines) on weight gain,lipid metabolism,glucose metabolism in an obese murine mod...AIM:To compare the effects of four Bifidobacteria strains(Bifidobacteria L66-5,L75-4,M13-4 and FS31-12,originated from normal human intestines) on weight gain,lipid metabolism,glucose metabolism in an obese murine model induced by high-fat diet.METHODS:Forty-eight Sprague-Dawley rats were randomly divided into six groups.Control group received standard chow,model group received high-fat diet,and intervention groups received high-fat diet added with different Bifidobacteria strains isolated from healthy volunteers' fresh feces.All rats were executed at the 6th weekend.Body weight(BW),obese indexes,oral glucose tolerance test,serum and liver lipid and serum insulin(INS) were tested.Liver lipid deposition was classif ied pathologically.RESULTS:Compared with the model group,B.M13-4 improved BW gains(264.27 ± 26.91 vs 212.55 ± 18.54,P = 0.001) while B.L66-5 induced a decrease in BW(188.47 ± 11.96 vs 212.55 ± 18.54,P = 0.043).The rest two strains had no significant change in BW.All the four strains can reduce serum and liver triglyceride and significantly alleviate the lipid deposition in liver.All strains showed a trend of lowing serum and liver total cholesterol while B.L66-5 and B.FS31-12 did so more significantly.In addition,all the four strains showed no significant differences in serum INS and glucose level.CONCLUSION:The response of energy metabolism to administration of Bifidobacteria is strain dependent.Different strains of Bifidobacteria might drive different directions of fat distribution.展开更多
The results of silicon isotope analyses of Precambrian BIF are reported for the first time. The δ^(30)Si values of magnetite-quartzite in the Gongchangling ore deposit are between —0.9 and —2.2‰, which are obvious...The results of silicon isotope analyses of Precambrian BIF are reported for the first time. The δ^(30)Si values of magnetite-quartzite in the Gongchangling ore deposit are between —0.9 and —2.2‰, which are obviously different from those in host rocks (0.2——0.6‰). It is suggested that the BIF may be a product of chemical precipitation in Archean submarine hydrothermal environment. There is a possibility of using silicon isotopes to distinguish the protolith of metamorphic rocks and trace the origin of silicon of altered minerals.展开更多
The Archean atmospheric oxygen concentration and sulfur cycle was long debated. The banded iron formation (BIF) is a special type of the sedimentary formation, which has truly recorded the atmospheric and oceanic cond...The Archean atmospheric oxygen concentration and sulfur cycle was long debated. The banded iron formation (BIF) is a special type of the sedimentary formation, which has truly recorded the atmospheric and oceanic conditions at that time. In this study, the composition of multiple sulfur isotope (δ 34S/δ 33S/δ 32S) for sulfides bedded in the Archean (~2.7 Ga) BIFs, in Anshan-Benxi area of Liaoning Province has been measured. The value of △33S varies from -0.89‰ to +1.21‰, which shows very obvious mass-independent fractionation (MIF) signatures. These non-zero △33S values indicate that the Archean sulfur cycles are different from what it is today, which have been deeply influenced by gas phase photochemical reactions. Algoma-type BIFs which are closely related to the volcanic activity have negative △33S value, however, Superior-type BIFs which are far away from the volcanic center have positive △33S value. The δ 34S varies in a large range from -22.0‰ to +11.8‰, which indicates that the bacteria reduction activity has already existed at that time, and that the oceanic sulfate concentration has at least reached 1 mmol/L in local areas. Combined with the contemporaneous existence of the hematite, magnetite and the occurrence and preservation of the sulfur MIF, it can be inferred that the Archean atmospheric oxygen level must be at 10-2―10-3 of the present atmospheric level (PAL).展开更多
The REE signature of banded iron formations (BIF) and martite-goethite mineralization of the Njweng ridge (South Cameroon) are used here to decipher the nature of the ocean during the period of BIF precipitation. The ...The REE signature of banded iron formations (BIF) and martite-goethite mineralization of the Njweng ridge (South Cameroon) are used here to decipher the nature of the ocean during the period of BIF precipitation. The textures of typical BIF categories are also presented as the only sedimentary feature. Two types of BIF facies are present at Njweng: the oxide and silicate facies. These facies show two stages of phase transformations. The first is the transformation of the original magnetite mineral into martite by oxidation resulting in trellis texture;the second is a simultaneous transformation by hydration into goethite and dehydration into martite. The samples typically show LREE depleted patterns relative to HREE, a characteristic similar to that of modern seawater. Also the strong positive Eu anomalies from the samples indicate the involvement of hydrothermal plumes of volcanic origin such as at mid ocean ridges (MOR). Yttrium (Y) has a strong positive anomaly pointing to the transportation of REEs as aqueous complexes within these ancient seas. The BIF samples have no positive Ce anomalies, suggesting that the oceans at that time were more reducing with no Ce fractionation than in present day oceans. The martite-goethite mineralization rather shows a positive Ce anomaly that derived from the enrichment in REE during the weathering of REE-bearing minerals. These results are integrated into existing literature on REE in BIFs worldwide and provide new insights into these heretofore unstudied BIFs of the northern edge of the Congo Craton.展开更多
文摘AIM:To compare the effects of four Bifidobacteria strains(Bifidobacteria L66-5,L75-4,M13-4 and FS31-12,originated from normal human intestines) on weight gain,lipid metabolism,glucose metabolism in an obese murine model induced by high-fat diet.METHODS:Forty-eight Sprague-Dawley rats were randomly divided into six groups.Control group received standard chow,model group received high-fat diet,and intervention groups received high-fat diet added with different Bifidobacteria strains isolated from healthy volunteers' fresh feces.All rats were executed at the 6th weekend.Body weight(BW),obese indexes,oral glucose tolerance test,serum and liver lipid and serum insulin(INS) were tested.Liver lipid deposition was classif ied pathologically.RESULTS:Compared with the model group,B.M13-4 improved BW gains(264.27 ± 26.91 vs 212.55 ± 18.54,P = 0.001) while B.L66-5 induced a decrease in BW(188.47 ± 11.96 vs 212.55 ± 18.54,P = 0.043).The rest two strains had no significant change in BW.All the four strains can reduce serum and liver triglyceride and significantly alleviate the lipid deposition in liver.All strains showed a trend of lowing serum and liver total cholesterol while B.L66-5 and B.FS31-12 did so more significantly.In addition,all the four strains showed no significant differences in serum INS and glucose level.CONCLUSION:The response of energy metabolism to administration of Bifidobacteria is strain dependent.Different strains of Bifidobacteria might drive different directions of fat distribution.
文摘The results of silicon isotope analyses of Precambrian BIF are reported for the first time. The δ^(30)Si values of magnetite-quartzite in the Gongchangling ore deposit are between —0.9 and —2.2‰, which are obviously different from those in host rocks (0.2——0.6‰). It is suggested that the BIF may be a product of chemical precipitation in Archean submarine hydrothermal environment. There is a possibility of using silicon isotopes to distinguish the protolith of metamorphic rocks and trace the origin of silicon of altered minerals.
基金National Natural Science Foundation of China (Grant No. 40273008)
文摘The Archean atmospheric oxygen concentration and sulfur cycle was long debated. The banded iron formation (BIF) is a special type of the sedimentary formation, which has truly recorded the atmospheric and oceanic conditions at that time. In this study, the composition of multiple sulfur isotope (δ 34S/δ 33S/δ 32S) for sulfides bedded in the Archean (~2.7 Ga) BIFs, in Anshan-Benxi area of Liaoning Province has been measured. The value of △33S varies from -0.89‰ to +1.21‰, which shows very obvious mass-independent fractionation (MIF) signatures. These non-zero △33S values indicate that the Archean sulfur cycles are different from what it is today, which have been deeply influenced by gas phase photochemical reactions. Algoma-type BIFs which are closely related to the volcanic activity have negative △33S value, however, Superior-type BIFs which are far away from the volcanic center have positive △33S value. The δ 34S varies in a large range from -22.0‰ to +11.8‰, which indicates that the bacteria reduction activity has already existed at that time, and that the oceanic sulfate concentration has at least reached 1 mmol/L in local areas. Combined with the contemporaneous existence of the hematite, magnetite and the occurrence and preservation of the sulfur MIF, it can be inferred that the Archean atmospheric oxygen level must be at 10-2―10-3 of the present atmospheric level (PAL).
文摘The REE signature of banded iron formations (BIF) and martite-goethite mineralization of the Njweng ridge (South Cameroon) are used here to decipher the nature of the ocean during the period of BIF precipitation. The textures of typical BIF categories are also presented as the only sedimentary feature. Two types of BIF facies are present at Njweng: the oxide and silicate facies. These facies show two stages of phase transformations. The first is the transformation of the original magnetite mineral into martite by oxidation resulting in trellis texture;the second is a simultaneous transformation by hydration into goethite and dehydration into martite. The samples typically show LREE depleted patterns relative to HREE, a characteristic similar to that of modern seawater. Also the strong positive Eu anomalies from the samples indicate the involvement of hydrothermal plumes of volcanic origin such as at mid ocean ridges (MOR). Yttrium (Y) has a strong positive anomaly pointing to the transportation of REEs as aqueous complexes within these ancient seas. The BIF samples have no positive Ce anomalies, suggesting that the oceans at that time were more reducing with no Ce fractionation than in present day oceans. The martite-goethite mineralization rather shows a positive Ce anomaly that derived from the enrichment in REE during the weathering of REE-bearing minerals. These results are integrated into existing literature on REE in BIFs worldwide and provide new insights into these heretofore unstudied BIFs of the northern edge of the Congo Craton.
