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1.
Levans produced by four Zymomonas mobilis strains showed antitumour activity against sarcoma 180 and Ehrlich carcinoma in Swiss albino mice. Levans from two strains (ZAP and CP4) had the highest effects. NMR analysis showed that the polymers were composed only of fructose units. The results suggested that the antineoplasic effect is associated to the polysaccharide molecular weight and that a particular molecular weight range may be responsible for this effect. 相似文献
2.
Variation in the ribosomal internal transcribed spacers (ITS1 and ITS2) among eight taxa of the Mimulus guttatus species complex 总被引:1,自引:0,他引:1
The internal transcribed spacer region (ITS1 and ITS2) of the 18S-25S
nuclear ribosomal DNA sequence and the intervening 5.8S region were
sequenced from three individuals in each of eight taxa of the Mimulus
guttatus species complex. Three discrete variants, or "types," of ITS
sequences were found, among which 30%-40% of sites differed, compared with
1%-2% within types. Dot plots indicate that these types were not related by
conspicuous rearrangements or inversions. More than one ITS type was often
found in the same taxon, and two of three ITS types span species
boundaries, indicating their presence prior to speciation. These ITS
sequences showed essentially no positional homology with the nearest
sequenced relative, tomato. In contrast, the 5.8S region was relatively
unvaried, with 8 of 162 sites varied in the sample among all eight taxa.
The phylogeny inferred by the most common ITS sequence type, rooted by the
two other ITS types, agreed with isozymes in showing the distinctness of M.
nudatus, M. laciniatus, and M. tilingii from the other five taxa.
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3.
Variation in heat shock proteins within tropical and desert species of poeciliid fishes 总被引:8,自引:0,他引:8
Norris CE; diIorio PJ; Schultz RJ; Hightower LE 《Molecular biology and evolution》1995,12(6):1048-1062
The 70-kilodalton heat shock protein (hsp70) family of molecular
chaperones, which contains both stress-inducible and normally abundant
constitutive members, is highly conserved across distantly related taxa.
Analysis of this protein family in individuals from an outbred population
of tropical topminnows, Poeciliopsis gracilis, showed that while
constitutive hsp70 family members showed no variation in protein isoforms,
inducibly synthesized hsp70 was polymorphic. Several species of
Poeciliopsis adapted to desert environments exhibited lower levels of
inducible hsp70 polymorphism than the tropical species, but constitutive
forms were identical to those in P. gracilis, as they were in the
confamilial species Gambusia affinis. These differences suggest that
inducible and constitutive members of this family are under different
evolutionary constraints and may indicate differences in their function
within the cell. Also, northern desert species of Poeciliopsis synthesize a
subset of the inducible hsp70 isoforms seen in tropical species. This
distribution supports the theory that ancestral tropical fish migrated
northward and colonized desert streams; the subsequent decrease in
variation of inducible hsp70 may have been due to genetic drift or a
consequence of adaptation to the desert environment. Higher levels of
variability were found when the 30- kilodalton heat shock protein (hsp30)
family was analyzed within different strains of two desert species of
Poeciliopsis and also in wild-caught individuals of Gambusia affinis. In
both cases the distribution of hsp30 isoform diversity was similar to that
seen previously with allozyme polymorphisms.
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4.
Antioxidants located in both the hydrophilic and lipophilic compartments of plasma are actively involved as a defense system against reactive oxygen species (ROS), which are continuously generated in the body due to both normal metabolism and disease. However, when the production of ROS is not controlled, it leads to cellular lipid, protein, and DNA damage in biological systems. Several assays to measure 'total' antioxidant capacity of plasma have been developed to study the involvement of oxidative stress in pathological conditions and to evaluate the functional bioavailability of dietary antioxidants. Conventional assays to determine antioxidant capacity primarily measure the antioxidant capacity in the aqueous compartment of plasma. Consequently, water-soluble antioxidants such as ascorbic acid, uric acid and protein thiols mainly influence these assays, whereas fat-soluble antioxidants such as tocopherols and carotenoids play only a minor role. However, there are active interactions among antioxidants located in the hydrophilic and lipophilic compartments of plasma. Therefore, new approaches to define the 'true' total antioxidant capacity of plasma should reflect the antioxidant network between water- and fat-soluble antioxidants in plasma. Revelation of the mechanism of action of antioxidants and their true antioxidant potential will help us to optimize the antioxidant defenses in the body. 相似文献
5.
Youn DY Lee DH Lim MH Yoon JS Lim JH Jung SE Yeum CE Park CW Youn HJ Lee JS Lee SB Ikawa M Okabe M Tsujimoto Y Lee JH 《American journal of physiology. Endocrinology and metabolism》2008,295(6):E1349-E1357
Bcl-2 interacting cell death suppressor (Bis), also known as Bag3 or CAIR-1, is involved in antistress and antiapoptotic pathways. In addition to Bcl-2, Bis binds to several proteins, suggesting it has diverse functions in normal and pathological conditions. To better define the physiological function of Bis in vivo, we developed bis-deficient mice with a cre-loxP system. Targeted disruption of exon 4 of the bis gene was demonstrated by Southern blotting and PCR, and Western blotting showed that no intact or truncated Bis protein was synthesized in bis(-/-) mice. While heterozygotes were fertile and appeared normal, Bis-deficient mice showed growth retardation and died by 3 wk after birth. The relative weight of the thymus and spleen was reduced and the total numbers of white blood cells, splenocytes, and thymocytes were significantly reduced compared with wild-type littermates. Serum profiles indicated significant hypoglycemia as well as decrease in triglyceride and cholesterol levels. Expression profiles of metabolic genes indicated that gluconeogenesis and beta-oxidation are activated in the liver of bis(-/-) mice. This activation, as well as a decrease in peripheral fat and an induction of fatty liver, appears to be an adaptive response to hypoglycemia. Our study reveals that the absence of Bis has considerable influences on postnatal growth and survival, possibly due to a nutritional impairment. 相似文献
6.
Qin J Yeum KJ Johnson EJ Krinsky NI Russell RM Tang G 《The Journal of nutritional biochemistry》2008,19(9):612-618
Concentrations of 9-cis beta-carotene (9-cis betaC) and zeta-carotene (zetaC) in biological samples may provide crucial information on the biological activities of these carotenoids. However, in high-performance liquid chromatography (HPLC) these carotenoids are often co-eluted. Therefore, there is an urgent need to develop a method for 9-cis betaC and zetaC quantitation. Both 9-cis betaC and zetaC have peak absorbance at 400 and 450 nm, respectively, whereas only 9-cis betaC has peak absorbance at 475 nm. We developed a HPLC method to quantitate 9-cis betaC and zetaC by using peak absorbance ratios. The 9-cis betaC/zetaC peak area was monitored at 475, 450 and 400 nm. The 9-cis betaC was quantified by using absorbance value at 475 nm; zetaC was then calculated from the 9-cis betaC/zetaC peak at 400 nm by subtracting 9-cis betaC contribution at 400 nm using the 400-nm/475-nm peak absorbance ratio of 9-cis betaC (0.39). This method was applied to determine 9-cis betaC and zetaC concentrations in serum and breast milk samples (n=12) from American lactating women and serum and breast adipose tissue samples (n=16) from Korean women with either benign or malignant breast tumors. 9-cis betaC concentrations in serum and breast milk of American women, and serum and adipose tissue of Korean women were 7.1+/-0.8 and 1.1+/-0.2 nM, and 15.6+/-1.1 nM and 0.2+/-0.1 nmol/g, respectively. zetaC concentrations in the above samples were 54.2+/-7.2 and 8.3+/-1.8 nM, and 49.0+/-3.9 nM and 0.3+/-0.1 nmol/g, respectively. 相似文献
7.
While long-term fixation and storage of specimens is common and useful for many research projects, it is particularly important for space flight investigations where samples may not be returned to Earth for several months (International Space Station) or years (manned mission to Mars). We examined two critical challenges of space flight experimentation: the effect of long-term fixation on the quality of mouse bone preservation and the preservation of antigens and enzymes for both histochemical and immunohistochemical analyses, and how the animal/sample processing affects the preservation. We show that long-term fixation minimally affects standard histological staining, but that enzyme histochemistry and immunolabeling are greatly compromised. Further, we demonstrate that whole animal preservation is not as suitable as whole leg or stripped leg preservation for long-term fixation and all histological analyses. Overall, we recommend whole leg processing for long-term storage of bone specimens in fixative prior to embedding in plastic for histological examination. 相似文献
8.
Y S Gu I S Kim J H Park S H Lee D C Park D M Yeum C I Ji S H Kim K Wakabayashi S B Kim 《Bioscience, biotechnology, and biochemistry》2001,65(10):2284-2287
Pan-roasted beef showed a lower mutagenicity after various degrees of cooking than charcoaled one. The high mutagenicity of charcoaled beef was due to the formation of more heterocyclic amines, especially AalphaC (2-amino-9H-pyrido- [2,3-b]indole) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) because of rapid and direct heating on the surface of the meat at a high temperature. Seasoning decreased mutagenicity of pan-roasted beef except the very well done sample with unchanged heterocyclic amine contents, but increased mutagenicity of charcoaled beef with decreased levels of AalphaC and PhIP, probably due to the change of heterocyclic amine precursors or alternatively to the occurrence of other mutagens. 相似文献
9.
EO Ogueji CD Nwani SC Iheanacho CE Mbah CO Okeke A Yaji 《African Journal of Aquatic Science》2018,43(3):293-303
Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled. 相似文献
10.