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1.
Magnolol and its isomer honokiol are polyphenols with anti-oxidative and anti-inflammatory activities. We evaluated the effects of magnolol and honokiol supplementation alone or in combination with hen diets during the late laying cycle. A total of 540 Jingfen pink-shell laying hens (50 weeks old) were randomly assigned to six treatments: a control diet and diets supplemented with 300 mg/kg magnolol (M300), honokiol (H300), or 300 mg/kg total phenols with a magnolol/honokiol ratio of 2:1 (M200H100), 1:2 (M100H200), and 1:1 (M150H150). Compared with that of the control, all supplementation groups had higher laying rates and the M300, M100H200, and M150H150 groups showed comparatively lower feed conversion ratios. Magnolol and honokiol supplementation increased the Haugh units of fresh eggs at week 62 and alleviated the decline of the Haugh units of eggs stored for 14 days. Compared with that of the control group, the serum total antioxidant capacity of the M100H200 and M150H150 groups significantly increased, and all supplementation groups had higher total antioxidant capacity and lower malondialdehyde content in the liver. With respect to lipid metabolism, the M200H100 and M150H150 groups had lower total and relative liver weights compared with those of the control and H300 groups. The mRNA expression levels of CCAAT enhancer binding protein alpha, sterol regulatory element binding protein-1, fatty acid synthase and stearyl coenzyme A desaturase 1 involved in lipogenesis; microsomal triglyceride transfer protein and apolipoprotein B involved in fatty acid transport; and the proinflammatory cytokine interleukin-1 beta were lower in all supplementation groups compared with those in the control. With respect to gut health, the heights of the jejunum and ileum villi significantly increased in all supplementation groups compared with those of the control, and the jejunum villus heights of the M300 and M150H150 groups were higher than those of the H300 and M100H200 groups. The H300 and M150H150 groups had higher mRNA expression levels of zonula occludens-1 in the ileum compared with those in the control and M300 groups, whereas all supplementation groups had higher mRNA levels of claudin-1 than that of the control group. In conclusion, magnolol and honokiol improved hen performance and the albumen quality of fresh and stored eggs by improving the antioxidant capacity, liver lipid metabolism, and intestinal health of laying hens. The combination of magnolol and honokiol at a 1:1 ratio may be an optimal choice for hen diet supplementation.  相似文献   

2.
Pyrimido[1,2-a]-purin-10(3H)-one (M1G) is a secondary DNA damage product arising from primary reactive oxygen species (ROS) damage to membrane lipids or deoxyribose. The present study investigated conditions that might lead to artifactual formation or loss of M1G during DNA isolation. The addition of antioxidants, DNA isolation at low temperature or non-phenol extraction methods had no statistically significant effect on the number of M1G adducts measured in either control or positive control tissue samples. The number of M1G adducts in nuclear DNA isolated from brain, liver, kidney, pancreas, lung and heart of control male rats were 0.8, 1.1, 1.1, 1.1, 1.8 and 4.2 M1G/108 nt, respectively. In rat liver tissue, the mitochondrial DNA contained a 2-fold greater number of M1G adducts compared with nuclear DNA. Overall, the results from this study demonstrated that measuring M1G is a reliable way to assess oxidative DNA damage because the number of M1G adducts is significantly affected by the amount of ROS production, but not by DNA isolation procedures. In addition, this study confirmed that the background number of M1G adducts reported in genomic DNA could have been overestimated by one to three orders of magnitude in previous reports.  相似文献   

3.
Defining and quantifying biomass?Cdensity relationships in dense plant stands has been a long-standing issue in both theoretical and empirical studies. Most existing/traditional studies focus on whole plant individuals, without considering different plant components (e.g., stem, branch and leaf). However, the analysis of biomass?Cdensity relationships for different plant parts is linked to those for whole plants, and thus important for understanding plant strategies for utilizing resources and community dynamics. In our study, we investigated standing stem (M S), branch (M B) and leaf (M L) biomass?Cdensity relationships, across a range of forest communities in China. The results showed that there was no constant predicted value (e.g., ?1/2 or ?1/3 for M S; ?1/2, ?1/3 or 0 for M B and M L) that can describe all the relationships, and that the scaling exponents for stem, branch and leaf biomass varied across different forest types. In particular, standing leaf biomass (leaf biomass per unit area) was not constant in these forest communities. Furthermore, stem biomass?Cdensity lines were steeper than corresponding branch and leaf lines across most of these forest communities.  相似文献   

4.
The polysaccharide-chain fragments of rooster-comb dermatan sulfates (RC-20 and RC-30) were obtained by chondroitinase AC-II digestion and by periodate oxidation, followed by alkaline cleavage, and their structures analyzed both quantitatively and qualitatively. RC-20 having a lower d-glucuronic acid content (22.6%) is composed preponderantly of large clusters of N-acetyldermosine sulfate (Mr~17 600–41 000) at the nonreducing terminal, whereas RC-30, having a higher d-glucuronic acid content, (41.4%) is poor in this cluster. Both RC-20 and RC-30 have an N-acetyldermosine sulfate cluster (Mr 6500–7300) within the polysaccharide chains. Most N-acetylchondrosine sulfate units of RC-20 and RC-30 exist as clusters, the large clusters (Mr~17 600) being preponderant in RC-30; both RC-20 and RC-30 contain a large proportion of N-acetylchondrosine sulfate clusters (Mr 3500 and 9000) that corresponds to the uronic acid content. In RC-30, most N-acetyldermosine disulfate units (13.4%) are linked to N-acetylchondrosine sulfate units or clusters.  相似文献   

5.
《Insect Biochemistry》1989,19(4):383-391
Aminopeptidase (soluble form Mr 110,000), carboxypeptidase A (soluble form Mr 47,000), maltase (a dimer composed of two identical Mr 60,000 subunits) and trypsin (two charge isomers with Mr 34,000) are found in major amounts in the crop and midgut tissue, whereas amylase (a trimer of three identical Mr 18,000 subunits) and cellobiase (a trimer of three identical Mr 27,000 subunits) occur mainly in the crop and midgut contents. Subcellular fractions of midgut cells were obtained by conventional homogenization, followed by differential centrifugation or differential calcium precipitation. The results suggest that part of the aminopeptidase and carboxypeptidase A activity is bound to microvilli, that major amounts of trypsin and maltase are trapped in the cell glycocalyx and finally that soluble aminopeptidase, amylase and cellobiase occur in intracellular vesicles. The data support the hypothesis that most protein and carbohydrate digestion takes place in the crop under the action of enzymes passed forward from the midgut, after being secreted by exocytosis. Nevertheless, part of the intermediate and final digestion occurs at the surface of the midgut cells. The peculiar features of the digestion of P. aequinoctialis beetles, including their partly fluid peritrophic membranes, are thought to be derived from putative Coleoptera ancestors.  相似文献   

6.
Two field exercises were carried out to compare chlorophyll a fluorescence measurements taken in the field by field teams working on the same project. In the first exercise (2007, Passo Pura, Ampezzo, Udine, Northern Italy) the operators took measurements on the same leaf areas (maintaining fixed leaf clips); in the second (2009, Monterotondo Marittimo, Grosseto, Central Italy) the teams worked independently, but addressing a common research question. The results of the first exercise showed that: (a) FV/FM was stable and had little variation among teams and instruments; (b) the results from the different teams correlated well; (c) the most suitable parameters of fast kinetics analysis are those measured on the normalized fluorescence transients. In the second exercise, when the teams worked independently, the results were much more variable and the correlations between measurements of different operators were weak. These results suggest that field chlorophyll a fluorescence measurements taken by different teams/operators can be comparable only if particular care is taken to the internal variability of the samples and a standardized sampling strategy is applied. A statistically sound representation of a population can be then reached.  相似文献   

7.
8.
J M Storey  K B Storey 《Cryobiology》1982,19(2):185-194
The kinetic properties of cytoplasmic glycerol-3-P dehydrogenase from the third instar larva of the gall fly, Eurosta solidaginis, were studied with emphasis on temperature effects on the enzyme and the regulation of enzyme activity during the synthesis of the cryoprotectant, glycerol. Isoelectrofocusing revealed one major and two minor forms of the enzyme with no alteration in the pI's or relative activities of the forms in larvae acclimated to 24 versus ?30 °C. Kinetic properties of the enzyme were also the same in larvae acclimated to high and low temperatures. Arrhenius plots were linear over a 30 to 0 °C range with an activation energy of 12,630 ± 185 cal/mol and a Q10 of 2.16. The Km for dihydroxyacetone-P was constant, at 50 μM, between 30 and 10 °C but increased by 75% at 0 °C; this increase may be a factor in the cessation of glycerol synthesis which occurs below 5 °C in this species. The Km(NADH), by contrast, was higher (5–6 μM) at 30 °C but decreased (3 μM) at lower temperatures. In the reverse direction, Km's were 340 μM for glycerol-3-P and 12 μM for NAD+. Effects of most inhibitors (of the forward reaction), glycerol-3-P (Ki = 2.4 mM), NAD+ (Ki = 0.2 mM), ATP, Mg·ATP, and Pi, were unaltered by assay temperature but ADP effects were potentiated by low temperature while citrate inhibition was greatest at high temperatures. Glycerol and sorbitol, which accumulate as cryoprotectants in E. solidaginis, had no significant effects on kinetic constants at any temperature but decreased the Vmax activity of the enzyme. Thermal inactivation studies showed an increased thermal stability of the larval enzyme compared to the homologous enzyme from rabbit muscle while added polyols stabilized enzyme activity, decreasing the rate of enzyme inactivation at 50 °C.  相似文献   

9.
H. van Ormondt  B. Hesper 《Gene》1983,21(3):217-226
The nucleotide sequences of human adenovirus serotypes 12 (Ad 12, oncogenic subgroup A), 7 (Ad7, weakly oncogenic subgroup B) and 5 (Ad5, non-oncogenic subgroup C) DNAs have been compared. The region studied stretches from the termination codon of region Ela (m.p. 4.2) and comprises the entire region of the three viral DNAs. ending at the polyadenylation signal of the gene for viral polypeptide IVa2 (m.p. 11.2). The homology in the sequences encoding the Elb proteins of Mr 20000 and Mr 55000 is 55–60%, when two serotypes are compared, and about 45% in a three-strain comparison. However, a short internal segment encoding the C terminus of the Mr 20000 protein, and at the same time amino acids 23-120 of the Mr 55000 protein show a much higher degree of divergence in the three strains, as do the noncoding areas. The present study does not reveal how the three serotypes are phylogenetically related.  相似文献   

10.
Szilvia Z. Tóth 《BBA》2005,1708(2):275-282
The effects of DCMU (3-(3′,4′-dichlorophenyl)-1,1-dimethylurea) on the fluorescence induction transient (OJIP) in higher plants were re-investigated. We found that the initial (F0) and maximum (FM) fluorescence levels of DCMU-treated leaves do not change relative to controls when the treatment is done in complete darkness and DCMU is allowed to diffuse slowly into the leaves either by submersion or by application via the stem. Simultaneous 820 nm transmission measurements (a measure of electron flow through Photosystem I) showed that in the DCMU-treated samples, the plastoquinone pool remained oxidized during the light pulses whereas in uninhibited leaves, the FM level coincided with a fully reduced electron transport chain. The identical FM values with and without DCMU indicate that in intact leaves, the FM value is independent of the redox state of the plastoquinone pool. We also show that (i) the generally observed F0 increase is probably due to the presence of (even very weak) light during the DCMU treatment, (ii) vacuum infiltration of leaf discs leads to a drastic decrease of the fluorescence yield, and in DCMU-treated samples, the FM decreases to the I-level of their control (leaves vacuum infiltrated with 1% ethanol), (iii) and in thylakoid membranes, the addition of DCMU lowers the FM relative to that of a control sample.  相似文献   

11.
The UL15 gene of herpes simplex virus (HSV) is one of several genes required for the packaging of viral DNA into intranuclear B capsids to produce C capsids that become enveloped at the inner nuclear membrane. A rabbit antiserum directed against UL15-encoded protein recognized three proteins with apparent Mrs of 79,000, 80,000, and 83,000 in highly purified B capsids. The 83,000-Mr protein was detected in type C capsids and comigrated with the product of a UL15 cDNA transcribed and translated in vitro. The 83,000- and 80,000-Mr proteins were readily detected in purified virions. Inasmuch as (i) none of these proteins were detectable in capsids purified from cells infected with HSV-1(ΔUL15), a virus lacking an intact UL15 gene, and (ii) corresponding proteins in capsids purified from cells infected with a recombinant virus [HSV-1(R7244), containing a 20-codon tag at the 3′ end of UL15] were decreased in electrophoretic mobility relative to the wild-type proteins, we conclude that the proteins with apparent Mrs of 83,000, 80,000, and 79,000 are products of UL15 with identical C termini. The 79,000-, 80,000-, and 83,000-Mr proteins remained associated with B capsids in the presence of 0.5 M guanidine HCl and remained detectable in capsids treated with 2.0 M guanidine HCl and lacking proteins associated with the capsid core. These data, therefore, indicate that UL15-encoded proteins are integral components of B capsids. Only the 83,000-Mr protein was detected in B capsids purified from cells infected with viruses lacking the UL6, UL17, or UL28 genes, which are required for DNA cleavage and packaging, suggesting that capsid association of the 80,000- and 79,000-Mr proteins requires intact cleavage and packaging machinery. These data, therefore, indicate that capsid association of the 80,000- and 79,000-Mr UL15-encoded proteins reflects a previously unrecognized step in the DNA cleavage and packaging reaction.  相似文献   

12.
In response to the first Dutch elm disease (DED) pandemic, Siberian elm, Ulmus pumila, was planted to replace the native elm, U. minor, in Italy. The potential for hybridization between these two species is high and repeated hybridization could result in the genetic swamping of the native species and facilitate the evolution of invasiveness in the introduced species. We used genetic markers to examine the extent of hybridization between these two species and to determine the pattern of introgression. We quantified and compared the level of genetic diversity between the hybrids and the two parental species. Hybrids between U. pumila and U. minor were common. The pattern of introgression was not as strongly biased towards U. pumila as was previously observed for hybrids between U. rubra and U. pumila in the United States. The levels of heterozygosity were similar between U. minor and the hybrids and both groups had higher levels of heterozygosity relative to U. pumila. The programs Structure and NewHybrids indicated the presence of first- (F1) and second- generation (F2) hybrids and of backcrosses in the hybrid population. The presence of healthy DED resistant U. minor individuals combined with the self-compatibility of U. minor could help explain the presence of F2 individuals in Italy. The presence of F2 individuals, where most of the variability present in the hybrids will be released, could facilitate rapid evolution and the potential evolution of invasiveness of U. pumila in Italy.  相似文献   

13.
A left mandibular fragment bearing M1–M3 recovered from the mudstones underlying an Upper Siwalik bentonitised tuff exposed 0.375 km NW of Barakhetar village, Jammu district, Jammu and Kashmir (state), India, is described here. The new specimen represents the first mandibular fragment of fossil Golunda with all three molars in situ. Based on crown morphology of the molars, it is tentatively referred to Golunda kelleri Jacobs, 1978, possibly representing a lineage distinct from G. ellioti ancestry.  相似文献   

14.
Parasympathetic activity decreases heart rate (HR) by inhibiting pacemaker cells in the sinoatrial node (SAN). Dysregulation of parasympathetic influence has been linked to sinus node dysfunction and arrhythmia. RGS (regulator of G protein signaling) proteins are negative modulators of the parasympathetic regulation of HR and the prototypical M2 muscarinic receptor (M2R)-dependent signaling pathway in the SAN that involves the muscarinic-gated atrial K+ channel IKACh. Both RGS4 and RGS6-Gβ5 have been implicated in these processes. Here, we used Rgs4−/−, Rgs6−/−, and Rgs4−/−:Rgs6−/− mice to compare the relative influence of RGS4 and RGS6 on parasympathetic regulation of HR and M2R-IKACh-dependent signaling in the SAN. In retrogradely perfused hearts, ablation of RGS6, but not RGS4, correlated with decreased resting HR, increased heart rate variability, and enhanced sensitivity to the negative chronotropic effects of the muscarinic agonist carbachol. Similarly, loss of RGS6, but not RGS4, correlated with enhanced sensitivity of the M2R-IKACh signaling pathway in SAN cells to carbachol and a significant slowing of M2R-IKACh deactivation rate. Surprisingly, concurrent genetic ablation of RGS4 partially rescued some deficits observed in Rgs6−/− mice. These findings, together with those from an acute pharmacologic approach in SAN cells from Rgs6−/− and Gβ5−/− mice, suggest that the partial rescue of phenotypes in Rgs4−/−:Rgs6−/− mice is attributable to another R7 RGS protein whose influence on M2R-IKACh signaling is masked by RGS4. Thus, RGS6-Gβ5, but not RGS4, is the primary RGS modulator of parasympathetic HR regulation and SAN M2R-IKACh signaling in mice.  相似文献   

15.
The youngest fossil Golunda (Rodentia, Muridae) is described from the Late Pleistocene fluvio-lacustrine deposits, exposed at Dulam (Bageshwar), Kumaun Lesser Himalaya, India. The age of fossiliferrous horizon is estimated as 31,000 yr BP. A new species, Golunda dulamensis nov. sp. has highly derived characters, e.g., antero-posteriorly stretched molars, upper molars with more length and less width, stephanodonty, cusps in M3 strongly inclined backward giving the molars a very stretched aspect, and metaconid and entoconid in M3 forming almost straight lingual row of the cusps. Gdulamensis nov. sp. is most similar to present day Gellioti but differs from the later slightly by larger size, a thin connection between t4 and t5 in M1, and comparatively larger entoconid and very weakly developed antero-labial cusp in M3. We suggest that highly specialized molars of Gdulamensis nov. sp. and present day Gellioti are derivable through Gkelleri. We also propose that Golunda migrated from Asia to Africa, not from Africa to Asia as was thought by earlier workers.  相似文献   

16.
Empirical studies of cardiovascular variables suggest that relative heart muscle mass (relative Mh) is a good indicator of the degree of adaptive specialization for prolonged locomotor activities, for both birds and mammals. Reasonable predictions for the maximum oxygen consumption of birds during flight can be obtained by assuming that avian heart muscle has the same maximum physiological and biomechanical performance as that of terrestrial mammals. Thus, data on Mh can be used to provide quantitative estimates for the maximum aerobic power input (aerobic Pi,max) available to animals during intense levels of locomotor activity. The maximum cardiac output of birds and mammals is calculated to scale with respect to Mh (g) as 213 Mh0.88+-0.04 (ml min-1), while aerobic Pi,max is estimated to scale approximately as 11 Mh0.88+-0.09 (W). In general, estimated inter-species aerobic Pi,max, based on Mh for all bird species (excluding hummingbirds), is calculated to scale with respect to body mass (Mb in kg) as 81 Mb0.82+-0.11 (W). Comparison of family means for Mh indicate that there is considerable diversity in aerobic capacity among birds and mammals, for example, among the medium to large species of birds the Tinamidae have the smallest relative Mh (0.25 per cent) while the Otidae have unusually large relative Mh (1.6 per cent). Hummingbirds have extremely large relative Mh (2.28 per cent), but exhibit significant sexual dimorphism in their scaling of Mh and flight muscle mass, so that when considering hummingbird flight performance it may be useful to control for sexual differences in morphology. The estimated scaling of aerobic Pi,max (based on Mh and Mb in g) for male and female hummingbirds is 0.51 Mb0.83 +/-0.07 and 0.44 Mb0.85+- 0.11 (W), respectively. Locomotory muscles are dynamic structures and it might be anticipated that where additional energetic ''costs'' occur seasonally (e.g. due to migratory fattening or the development of large secondary sexual characteristics) then the relevant cardiac and locomotor musculature might also be regulated seasonally. This is an important consideration, both due to the intrinsic interest of studying muscular adaptation to changes in energy demand, but also as a confounding variable in the practical use of heart rate to estimate the energetics of animals. Haemoglobin concentration (or haematocrit) may also be a confounding variable. Thus, it is concluded that data on the cardiovascular and flight muscle morphology of animals provides essential information regarding the behavioural, ecological and physiological significance of the flight performance of animals.  相似文献   

17.
C. Arambourg has described a new genus and a new species of a cercopithecid Anomalopithecus bicuspidatus (1), from the Ain Brimba Villafranchian site (Tunisia). This form is based on heterogeneous material: the species holotype is an upper incisor of Hyaena striata praecursor ARAMBOURG (1), meanwhile the syntypes (M2 and M3) belong to Macaca sylvanus cf. sylvanus.  相似文献   

18.
Two new RNase inhibitors, SaI14 (Mr, ~14,000) and SaI20 (Mr, ~20,000), were isolated and purified from a Streptomyces aureofaciens strain. The gene sai14, coding for SaI14 protein, was cloned and expressed in Escherichia coli. The alignment of the deduced amino acid sequence of SaI14 with that of barstar, the RNase inhibitor from Bacillus amyloliquefaciens, showed significant similarity between them, especially in the region which contains most of the residues involved in barnase-barstar complex formation.  相似文献   

19.
We derive a new continuous free energy formula for protein folding. We obtain the formula first by adding hydrophobic effect to a classical free energy formula for cavities in water. We then obtain the same formula by geometrically pursuing the structure that fits best the well-known global geometric features of native structures of globular proteins: 1. high density; 2. small surface area; 3. hydrophobic core; 4. forming domains for long polypeptide chains. Conformations of a protein are presented as an all atom CPK model where each atom is a ball B(xi,ri). All conformations satisfy generally defined steric conditions. For each conformation P of a globular protein, there is a closed thermodynamic system ΩPP bounded by the molecular surface MP. Both methods derive the same free energy aV(P)+bA(P)+cW(P), where a,b,c>0, V(P), A(P), and W(P) are volume of ΩP, area of MP, and area of the hydrophobic surface WPMP, which quantifies hydrophobic effect.Minimizing W(P) is sufficient to produce statistically significant native like secondary structures and hydrogen bonds in the proteins we simulated.  相似文献   

20.
A new genus, Heppneralis Park, gen. nov., of the subfamily Torodorinae, is described based on the type species, H. decorella sp. nov., and an additional new species, H. dumogaensis sp. nov., from Is. Sulawesi, Indonesia is described. The new genus is distinguished from all known genera of the subfamily by unique wing color markings on both wings, with R5 and M2 absent in the forewing and M2 absent in the hindwing.  相似文献   

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