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1.
Amplified fragment length polymorphisms (AFLPs) are a useful molecular tool for studying species with little available genetic
information; however, since universal primers are used contaminant DNA from non-target organisms may also be amplified. Cambium
tissue may contain fewer biotic contaminants or plant defense chemicals, than the more commonly used leaf tissue, and therefore
be more suitable for use as a source of DNA when using universal primers. On the other hand, cambium tissue can be difficult
to identify, yields low DNA and requires the bark of the tree to be damaged, thereby increasing the risk of introducing disease.
We show that within two tropical tree species, there are few differences between AFLP profiles obtained from either cambium
or leaf tissue from the same tree. We studied 50 Brosimum alicastrum individuals at 119 AFLP loci and 40 Swietenia macrophylla individuals at 112 AFLP loci. The matrix of S?rensen similarity indices between individual AFLP profiles for cambium samples
was strongly correlated to the matrix for leaf samples in each species (Mantel test; B. alicastrum r = 0.815, P < 0.001; S. macrophylla r = 0.895, P < 0.001). The phylogenetic relationship between the trees studied did not differ dependent on tissue type used and therefore
shows that both tissues can be used within a single study without introducing substantial error. 相似文献
2.
Ayoub A. Mohamed Abdel Aziem A. Ali Naji I. Ali Elshafaee H. Abusalama Mustafa I. Elbashir Ishag Adam 《Biological trace element research》2011,140(3):284-290
The study was conducted to investigate determinants (clinical, nutritional, and nonnutritional factors) of anemia among pregnant
women in Kassala, eastern Sudan. Sociodemographic characteristics were gathered; serum ferritin, zinc, albumin, and C-reactive
protein were measured using different laboratory methods in a cross-sectional study of 250 pregnant women. Of the 250 women,
58.4% had anemia (hemoglobin (HB) <11 g/dl), 6.8% had severe anemia (HB < 7 g/dl), 19.6% had iron deficiency (S-ferritin <15 μg/l),
14.8% had iron deficiency anemia (<11 g/dl and S-ferritin <15 μg/l), and 38% had zinc deficiency (<80 μg/ml). S-albumin, zinc,
and ferritin were significantly lower in patients with severe anemia. While age, gestational age, ferritin, and C-reactive
protein were not predictors for anemia, primigravidae (OR = 2.7, 95% CI = 1.1–6.7, P = 0.02), low S-albumin (OR = 5.9, 95% CI = 1.4–25.2, P = 0.01), and low S-zinc (OR = 2.6, 95% CI = 1.0–6.6, P = 0.03) were the predictors for anemia. While there was no significant correlation between hemoglobin, S-zinc, and S-ferritin,
there was a significant positive correlation between hemoglobin and S-albumin (r = 0.308, P = 0.001) and significant inverse correlation between hemoglobin and C-reactive protein (r = 0.169, P = 0.007). Thus, the role of chronic inflammation and zinc as possible contributing factors to anemia in pregnancy has important
implications for the clinical evaluation and treatment of these women. 相似文献
3.
Khaled M. Al-Qudah Ahmad A. Gharaibeh Maysa’a M. Al-Shyyab 《Biological trace element research》2010,136(1):40-47
The aim of this study was to determine the levels of trace minerals Zn, Cu, and Se, the effect of dermatophytosis on the level
of thiobarbituric acid reactive substances (TBARS) as an indicator of lipid peroxidation, the status of enzymatic and nonenzymatic
antioxidants, and the relationship between the mentioned trace minerals and antioxidant defense system in calves with dermatophytosis.
A total of 21 Holstein calves with clinically established diagnosis of dermatophytosis and an equal number of healthy ones
were included in this study. Results showed that 81% of mycotic isolates were Trichophyton verrucosum, while 19% were Trichophyton mentagrophytes. The level of Zn, Cu, Se, and glutathione (GSH) and the activity of the antioxidant enzymes, glutathione peroxidase (GSH-Px),
and superoxide dismutase (SOD) were significantly (P ≤ 0.05) lower. The plasma level of TBARS was significantly (P ≤ 0.05) higher in dermatophytic calves compared to healthy controls. SOD activity was fairly correlated with serum Cu and
positively correlated with serum Zn in healthy control (r = 0.68, P ≤ 0.05; r = 0.58, P ≤ 0.05) and in calves affected with dermatophytosis (r = 0.73, P ≤ 0.05; r = 0.55, P ≤ 0.05), respectively. GSH-Px activity was highly correlated with whole blood selenium (r = 0.78, P ≤ 0.05) in healthy control and dermatophytic subjects (r = 0.76, P ≤ 0.05). Our results demonstrated that in dermatophytosis, the alteration in the antioxidant enzyme activities might be secondary
to changes in their cofactor concentrations. 相似文献
4.
Seifi S Tabandeh MR Nazifi S Saeb M Shirian S Sarkoohi P 《Journal of physiology and biochemistry》2012,68(2):193-203
Available experimental data suggest that adiponectin and thyroid hormones have biological interaction in vivo. However, the
effects of thyroid hormones on adipose adiponectin gene expression in thyroid dysfunction are unclear. We induced hyper- (HYPER)
and hypothyroidism (HYPO) by daily administration of a 12 mg/l of levothyroxine and 250 mg/l of methimazole in drinking water
of rats, respectively, for 42 days. The white adipose tissues and serum sample were taken on days 15, 28, 42 and also 2 weeks
after treatment cessation. Analysis of adiponectin gene expression was performed by real-time PCR and 2−ΔΔct method. The levels of adipose tissue adiponectin mRNA in the HYPO rats were decreased during the 6-week treatment when compared
to control rats (<0.05) and were increased significantly 2 weeks after HYPO cessation (P < 0.05). This decline in adiponectin gene expression occurred in parallel with a decrease in T3, T4, fT3 and fT4 concentrations
(P < 0.05). In opposite to HYPO rats, adipose adiponectin gene expression was increased in HYPER rats during the 6-week treatment
in parallel with an increase the thyroid hormones concentrations (P < 0.05), and its expression was decreased 2 weeks after HYPER cessation (P < 0.05). Adiponectin gene expression levels showed significant negative correlations with concentrations of LDL (HYPO; r = −0.806, P = 0.001 and HYPER; r = −0.749, P = 0.002), triglyceride (HYPO; r = −0.825, P = 0.001 and HYPER; r = −0.824, P = 0.001) and significant positive correlations with concentrations of glucose (HYPO; r = 0.674, P = 0.004 and HYPER; r = 0.866, P = 0.001) and HDL (HYPO; r = 0.755, P = 0.001 and HYPER; r = 0.839, P = 0.001). The current study provides evidence that adiponectin gene expression in adipose tissue is regulated by thyroid
hormones at the translation level and that lipid and carbohydrate disturbances in a patient with thyroid dysfunction may be,
in part, due to adiponectin gene expression changes. 相似文献
5.
Mao-feng Yue Ren-chao Zhou Ye-lin Huang Guo-rong Xin Su-hua Shi Li Feng 《Journal of Plant Biology》2010,53(2):165-171
High levels of genetic variation enable species to adapt to changing environments and provide plant breeders with the raw
materials necessary for artificial selection. In the present study, six AFLP primer pairs were used to assess the genetic
diversity of Desmodium triflorum (L.) DC. from 12 populations in South China. A high percentage of polymorphic loci (P = 76.16%) and high total gene diversity (H
T = 0.310) were found, indicating that the genetic diversity of D. triflorum is high at the species level. Genetic diversity was also relatively high at the population level (P = 55.85%, H
e = 0.230). The coefficient of gene differentiation among populations (G
ST) was 0.255, indicating that while most genetic diversity resided within populations, there was also considerable differentiation
among populations. AMOVA also indicated 24.29% of the total variation to be partitioned among populations (ΦST = 0.243). UPGMA clustering analysis based on genetic distances showed that the 12 populations could be separated into three
subgroups: an eastern, a western, and a central-southern subgroup. However, a Mantel test revealed no significant correlation
(r = 0.286, p = 0.983) between the geographical distances and genetic distances separating these populations; mountain barriers to gene
flow and human disturbance may have confounded these correlations. The present study has provided some fundamental genetic
data that will be of use in the exploitation of D. triflorum. 相似文献
6.
Tomasz Kostka Marc Bonnefoy Laurent M. Arsac Sophie E. Berthouze Alain Belli Jean-René Lacour 《European journal of applied physiology and occupational physiology》1997,76(1):81-87
The aim of this study was to investigate the relationship between maximal anaerobic power (P
max) and corresponding optimal velocity (V
opt) and habitual physical activity (PA) on the one hand and with maximal oxygen consumption (V˙O2max) on the other hand, in elderly women. Twenty-nine community dwelling, healthy women aged 66–82 years participated in the
study. PA was evaluated using the Questionnaire d'Activite Physique Saint-Etienne (QAPSE) and expressed using two QAPSE activity
indices: mean habitual daily energy expenditure (MHDEE) and daily energy expenditure corresponding to leisure time sports
activities (sports activity). The subjects' P
max and V
opt were measured while they cycled on a friction-loaded non-isokinetic cycle ergometer. P
max was expressed relative to body mass [P
max/kg(W · kg−1)], and relative to the mass of two quadriceps muscles [P
max
/Quadr(W·kgQuadr
−1)]. A negative relationship between P
max/kg (Spearman's r = −0.56; P < 0.01), P
max/Quadr (r = −0.53; P < 0.01) and V
opt (r = −0.45; P < 0.05) and age was found. P
max/kg was positively associated with MHDEE (r = 0.51; P < 0.01) and sports activity (r = 0.58; P < 0.01), as were P
max/Quadr and V
opt (r = 0.55; P < 0.01 and r = 0.54; P < 0.01, respectively). P
max/kg, P
max/Quadr and V
opt correlated positively with V˙O2max. The positive relationship between ergometer measurements and PA indices was similar to that between V˙O2max and PA. P
max/kg was, moreover, closely related to V
opt (r = 0.77; P < 0.001). When a multiple stepwise regression analysis was used to select the variables influencing ergometer measurements,
MHDEE contributed significantly to P
max/kg variance, whereas sports activity contributed to P
max/Quadr and V
opt variances. In conclusion, the data from this cross-sectional study suggest that in healthy elderly women habitual PA, and
especially leisure time PA, alleviates the decline of the P
max of the quadriceps muscles.
Accepted: 30 January 1997 相似文献
7.
Genetic variation of four populations of Sargassum thunbergii (Mert.) O. Kuntze and one outgroup of S. fusiforme (Harv.) Setchell from Shandong peninsula of China was studied with random amplified polymorphic DNA (RAPD) and inter-simple
sequence repeat (ISSR) markers. A total of 28 RAPD primers and 19 ISSR primers were amplified, showing 174 loci and 125 loci,
respectively. Calculation of genetic diversity with different indicators (P%, percentage of polymorphic loci; H, the expected heterozygosity; I, Shannon’s information index) revealed low or moderate levels of genetic variations within each S. thunbergii population. High genetic differentiations were determined with pairwise Nei’s unbiased genetic distance (D) and fixation index (F
ST
) between the populations. The Mantel test showed that two types of matrices of D and F
ST
were highly correlated, whether from RAPD or ISSR data, r = 0.9310 (P = 0.008) and 0.9313 (P = 0.009) respectively. Analysis of molecular variance (AMOVA) was used to apportion the variations between and within the
S. thunbergii populations. It indicated that the variations among populations were higher than those within populations, being 57.57% versus
42.43% by RAPD and 59.52% versus 40.08% by ISSR, respectively. Furthermore, the Mantel test suggested that the genetic differentiations
between the four populations were related to the geographical distances (r > 0.5), i.e., they conformed to the IBD (isolation by distance) model, as expected from UPGMA (unweighted pair group method
with arithmetic averages) cluster analysis. As a whole, the high genetic structuring between the four S. thunbergii populations along distant locations was clearly indicated in the RAPD and ISSR analyses (r > 0.8) in our study. 相似文献
8.
Shortleaf pine (n = 93) and loblolly pine (n = 112) trees representing 22 seed sources or 16 physiographic populations were sampled from Southwide Southern Pine Seed
Source Study plantings located in Oklahoma, Arkansas, and Mississippi. The sampled trees were grown from shortleaf pine and
loblolly pine seeds formed in 1951 and 1952, prior to the start of intensive forest management across their native ranges.
Amplification fragment length polymorphism (AFLP) markers were developed and used to study genetic diversity and its structure
in these pine species. After screening 48 primer pairs, 17 and 21 pairs were selected that produced 794 and 647 AFLPs in shortleaf
pine and loblolly pine, respectively. High-AFLP-based genetic diversity exists within shortleaf pine and loblolly pine, and
most (84.73% in shortleaf pine; 87.69% in loblolly pine) of this diversity is maintained within physiographic populations.
The high value of unbiased measures of genetic identity and low value of genetic distance for all pairwise comparisons indicates
that the populations have similar genetic structures. For shortleaf pine, there was no significant correlation between geographic
distance and genetic distance (r = 0.28), while for loblolly pine there was a weak but significant correlation (r = 0.51). 相似文献
9.
Polymorphisms of caprine <Emphasis Type="Italic">GDF</Emphasis>9 gene and their association with litter size in Jining Grey goats 总被引:1,自引:0,他引:1
Feng T Geng CX Lang XZ Chu MX Cao GL Di R Fang L Chen HQ Liu XL Li N 《Molecular biology reports》2011,38(8):5189-5197
The exons 1, 2 and flanking region of growth differentiation factor 9 (GDF9) gene in five randomly selected does of Jining Grey, Boer and Liaoning Cashmere goats were amplified and analyzed. Thirteen
nucleotide differences were identified in GDF9 gene between sheep (AF078545) and goats. Four SNPs (G3288A in intron 1, G423A, A959C [Gln320Pro] and G1189A [Val397Ile]
in exon 2) were detected in four goat breeds with different prolificacy, in which G3288A was a new SNP in goats. The results
showed that loci 3288, 423 and 1189 in Boer goats, loci 3288 and 423 in Guizhou White goats, loci 423 and 1189 in Liaoning
Cashmere goats were all in complete linkage disequilibrium (D′ = 1, r
2 = 1), respectively. In moderate (Boer goat) and low prolificacy (Liaoning Cashmere goat) breeds, linkage analysis indicated
that there were more fervent linkage disequilibrium among loci 3288, 423 and 1189 than high prolificacy (Jining Grey and Guizhou
White goats) breeds. For the 959 locus, the genotype distribution showed obvious difference between high prolificacy breeds
and moderate or low prolificacy breeds (P < 0.05 or P < 0.01). The Jining Grey goat does with genotype CC or AC had 0.81 (P < 0.01) or 0.63 (P < 0.01) kids more than those with genotype AA, respectively. The present study preliminarily showed an association between
allele C at 959 locus of GDF9 gene and high litter size in Jining Grey goats. These results provide further evidence that the GDF9 gene may be significantly correlated with high prolificacy in goats. 相似文献
10.
Some key aspects of the reproductive strategy of the brown trout (Salmo trutta fario L.) in the Yadong River, Tibet, including spawning season, age at sexual maturity, fecundity and egg size, have been studied.
The majority of the samples were less than 215 mm and age ranged from 1 to 4 in both sexes, indicating that the majority of
the fish were younger and the pressure by overfishing was high. The spawning periodicity was determined to be between the
end of October and January, mainly in November and December. The ratio of male to female brown trout population (1.29:1 with
P > 0.05) suggested no sex significant differences, although males were significantly more abundant than females in October
(P < 0.0001) on monthly basis. Age and size of males and females at maturity was different and males matured earlier than females.
Fecundity was markedly correlated with their body weight (P < 0.001, r = 0.9255), standard length (P < 0.01, r = 0.8879), and gonad weight (P < 0.001, r = 0.9366). The mean size of mature eggs in the spawning season was: 4.0 ± 0.45 mm and tended to increase along with the female
spawners size (P < 0.001, r = 0.9641). Further researches about the brown trout population in the Yadong River should be conducted on issues such as
artificial reproduction, culture, conservation, management, and restocking. 相似文献
11.
Andrzej Bunio Renata Szygula Slawomir Tubek Grzegorz Krasowski 《Biological trace element research》2010,136(2):149-156
Environmental factors significantly influence the incidence and course of metabolic syndrome diseases such as diabetes and
obesity. The content of elements in rainwater is an indirect indicator of their presence in dust suspended in the air. In
this paper we present the relationships between the content of selected elements in rainwater and hospitalization frequencies
due to diabetes (E10–E13) and obesity (E66). It was assumed that the hospitalization frequency could be taken as a measure
of deterioration of the metabolic process in the course of diabetes and its complications. The observations concerned the
population of Opole Voivodeship, Poland (one million inhabitants), distributed in small communities of 44,000 to 151,000 inhabitants
during the years 2000–2002. In cases of diabetes E10–E13 for all subjects relevant correlation indicators were found for chromium
(r = 0.71), cadmium (r = 0.65), and lead (r = 0.66). Borderline relevance was seen for copper (r = 0.57) and zinc (r = 056). For diabetic men the statistically relevant correlations were chromium (r = 0.79), lead (r = 0.77), cadmium (r = 0.74), copper (r = 0.70), chloride (r = 0.69), zinc (r = 0.68), and iron (r = 0.64). For women the only relevant correlations were chromium (r = 0.62) and cadmium (r = 0.55). No significant correlations were found in obese individuals of both sexes. 相似文献
12.
The aim of the study was to determine the relationship of fluoride in drinking water to liver function in individuals living
in normal and seven endemic fluorosis areas of Punjab, India. The concentration of fluoride in drinking water of different
areas varied from 5.9 to 24.5 mg/L. Study group consisted of 705 patients in the age group between 20 and 60 years (mean age
of 39.35 ± 11.27) affected with osteodental fluorosis were compared with 300 age- and sex-matched controls (with mean age
of 35.28 ± 8.25 years). Biochemical data was analyzed by one-way analysis of variance (ANOVA) with post hoc Tukey–Kramer and
Bonferroni multiple comparison tests. The relationship between hepatic enzymes was calculated by Pearson’s correlation and
linear regression. The results revealed significantly (P < 0.001) higher concentration of serum fluoride in patients when compared to control. The mean activities of cyclic adenosine
monophosphate (AMP), alkaline phosphatase (ALKP), acid phosphatase (ACP), aspartate aminotransaminase (AST), and alanine aminotransaminase
(ALT) were significantly (P < 0.05–0.001) elevated in patients from all fluoride areas. ANOVA with post hoc Turkey–Kramer and Bonferroni multiple comparison
test demonstrated a significant (P < 0.0001) variance in the activities of cAMP, ALKP, ACP, AST, and ALT in fluorotic patients, with elevation in water fluoride
levels. Maximum elevation of 196.14% (ACP), 99.31% (cyclic adenosine monophosphate; cAMP), 72.08% (ALT), 60.14% (AST), and
least 21.35% (ALKP) was recorded in patients exposed to 24.5 mg/L fluoride in drinking water. There was positive correlation
between water fluoride, serum fluoride and AST (r = 0.77, 0.91), ALT (r = 0.82, 0.90), ALKP (r = 0.88, 0.97), and ACP (r = 0.74, 0.85). Pearson’s correlation demonstrated highly significant (P < 0.05) positive relationship between water fluoride and cAMP (regression equation: Y = 0.9807 ×+ 22.081 Y = 0.9807 \times + 22.081 , = 0.84; r = 0.92, P < 0.05). The increased levels of transaminases in fluorotic patients suggest alteration in liver functions. The level of
alkaline and acid phosphatase was increased during fluoride intoxication which is also an early marker of hepatic cell damage
because of its specificity and catalytic activity. The elevated levels of enzymes are reflective of bone disorders, which
are characterized by increased osteoblastic activity. There levels increased several times if cellular damage occurs in the
liver. The results suggest that fluoride exposure intensifies the activities of hepatic function enzymes in osteofluorosis. 相似文献
13.
David Blackburn Matthew Hamilton Chris Harwood Trevor Innes Brad Potts Dean Williams 《Tree Genetics & Genomes》2010,6(5):757-765
A trial was undertaken to assess the extent to which variation in sawn-board quality traits of plantation-grown Eucalyptus nitens is under genetic control and amenable to genetic improvement. Five hundred and sixty trees from 129 families and three central
Victorian races were sampled from an open-pollinated progeny trial in Tasmania, Australia. Acoustic wave velocity (AWV) was
assessed on standing trees and sawlogs. Wedges from disks extracted from sawlogs were assessed for basic density and checking.
Processed boards from 496 of the trees were assessed for board stiffness (static modulus of elasticity, MOE), and internal
and surface checking. Genetic differences among races were significant for AWV and MOE traits. The Southern race had the highest
mean values for these traits. Significant additive genetic variation within races was observed in all traits, demonstrating
that the quality of plantation-grown E. nitens boards could be improved through breeding. Estimated narrow-sense heritabilities were 0.85 for standing-tree AWV, 0.71 for
log AWV, 0.37 for board MOE, and ranged from 0.20 to 0.52 for checking traits. A strongly positive genetic correlation (r
g = 1.05) was observed between standing-tree AWV and board MOE, indicating that AWV could be used as a selection trait to improve
E. nitens board stiffness. The genetic correlation between basic density and board MOE was also positive (r
g = 0.62). However, a significant and adverse genetic correlation (r
g = 0.61) was identified between basic density and surface check length. Wood stiffness and checking traits were more-or-less
genetically independent, and genetic correlations between surface and internal checking were positive but only moderate (r
g = 0.48–0.52). 相似文献
14.
15.
S. Bermon M.-N. Magnié C. Dolisi J. Wolkiewiez M. Gastaud 《European journal of applied physiology and occupational physiology》1997,76(2):170-173
Non-smoking, male, professional firemen divers (n = 15) underwent two pulmonary function tests (PFT) separated by 6 years. Measured data were compared to European Coal Steel
Community recommended reference values to permit cross-sectional and then longitudinal study. Higher vital capacity (VC; P < 0.01) and forced expiratory volume in 1 s (FEV1; P < 0.05), and lower maximal mid-expiratory flow (MMEF) coefficient with VC (MMEF/VC; P < 0.05) were observed in both PFT. Diver's pulmonary diffusing capacity (DLCO) and the coefficient with alveolar volume (DLCO/V
A) showed significantly (P < 0.001) different evolution profiles than those expected from predicted values. In divers, DLCO and DLCO/V
A decreased from 104.0% to 91.4% and from 106.4% to 91.5% of predicted values respectively. Changes in DLCO and DLCO/V
A correlated positively with the initial measurement of DLCO (r = 0.67, P < 0.01) and DLCO/V
A (r = 0.74, P < 0.01) respectively, whereas no correlation between changes in pulmonary gas transfer function and age or diving history
parameters was found. Thus, it is suggested from our observations that hyperbaric atmosphere exposure increases the effects
of aging on pulmonary diffusing capacity and that pulmonary gas transfer function should be regularly tested in professional
and recreational divers.
Accepted: 22 February 1997 相似文献
16.
Stem respiration of ponderosa pines grown in contrasting climates: implications for global climate change 总被引:7,自引:0,他引:7
We examined the effects of climate and allocation patterns on stem respiration in ponderosa pine (Pinus ponderosa) growing on identical substrate in the cool, moist Sierra Nevada mountains and the warm, dry, Great Basin Desert. These environments
are representative of current climatic conditions and those predicted to accompany a doubling of atmospheric CO2, respectively, throughout the range of many western north American conifers. A previous study found that trees growing in
the desert allocate proportionally more biomass to sapwood and less to leaf area than montane trees. We tested the hypothesis
that respiration rates of sapwood are lower in desert trees than in montane trees due to reduced stem maintenance respiration
(physiological acclimation) or reduced construction cost of stem tissue (structural acclimation). Maintenance respiration
per unit sapwood volume at 15°C did not differ between populations (desert: 6.39 ± 1.14 SE μmol m−3 s−1, montane: 6.54 ± 1.13 SE μmol m−3 s−1, P = 0.71) and declined with increasing stem diameter (P = 0.001). The temperature coefficient of respiration (Q
10) varied seasonally within both environments (P = 0.05). Construction cost of stem sapwood was the same in both environments (desert: 1.46 ± 0.009 SE g glucose g−1 sapwood, montane: 1.48 ± 0.009 SE glucose g−1 sapwood, P = 0.14). Annual construction respiration calculated from construction cost, percent carbon and relative growth rate was greater
in montane populations due to higher growth rates. These data provide no evidence of respiratory acclimation by desert trees.
Estimated yearly stem maintenance respiration was greater in large desert trees than in large montane trees because of higher
temperatures in the desert and because of increased allocation of biomass to sapwood. By analogy, these data suggest that
under predicted increases in temperature and aridity, potential increases in aboveground carbon gain due to enhanced photosynthetic
rates may be partially offset by increases in maintenance respiration in large trees growing in CO2-enriched atmospheres.
Received: 4 November 1996 / Accepted: 23 January 1997 相似文献
17.
We assessed genetic variation in a total of 22 populations of the tree species Cordia africana Lam. in Ethiopia and analyzed the country-wide impact of population history, forest disturbance and alteration of land use
on extant intraspecific diversity. Amplified Fragment Length Polymorphisms (AFLPs) and chloroplast microsatellite markers
were investigated. The analyses of the AFLP data revealed high diversity in all investigated populations: the percentage of
polymorphic loci (PPL) ranged from 62.2% to 92.2% and Nei's gene diversity from 0.220 to 0.320 within the populations. The
mean PPL and the mean diversity within populations were 85.7% and 0.287, respectively. The analysis of molecular variance
revealed a moderate level of differentiation (ΦST = 0.07, p < 0.001) among the populations. The Mantel test proved a significant but low correlation (r = 0.31, p < 0.001) between the geographic distance and the genetic differentiation matrices. Only three different cpDNA haplotypes
were observed; no more than two haplotypes were found in any population. The dominant haplotype with an overall frequency
of 81% was observed in all populations. The level of differentiation among the populations was comparatively low at chloroplast
DNA (G
ST = 0.18, R
ST, N
ST = 0.22). The observed patterns and levels of genetic variation within and among the populations indicate that efficient gene
flow via pollen and seed is likely to be the main factor contributing to the maintenance of genetic diversity in natural and
disturbed conditions. 相似文献
18.
The objective was to determine the prevalence of iodine deficiency among hypothyroid patients and the effect of dietary goitrogens
on indices of iodine and thyroid status. This is a case-control study of 106 subjects who were recruited from King Abdulaziz
University Hospital, Jeddah. Blood and urine were collected for serum thyroid hormones, thyroid autoantibodies, thyroglobulin
(Tg) and urinary iodine concentration (UIC). Dietary iodine and goitrogenic food intake were assessed by questionnaire. Using
World Health Organization (WHO) cutoff values for UIC, both controls and cases were iodine deficient (85% and 83%, respectively).
Furthermore, dietary iodine was deficient in 23% of controls and 36% of cases. In cases, there was a positive association
between UIC levels and serum thyroid stimulating hormone (r = 0.405, p < 0.01) and a negative association with serum fT4 (r = −0.358, p < 0.01). Serum Tg antibody titers were also positively associated with dietary iodine (r = 0.328, p < 0.05). Patients with elevated serum autoantibodies had lower UIC and dietary iodine than those with normal serum autoantibodies.
UIC was associated with dietary goitrogens including turnip (r = 0.280, p < 0.05) and pine (r = 0.289, p < 0.05) among cases. Iodine deficiency is common and the consumption of dietary goitrogens is high among euthyroid and hypothyroid
subjects living in Jeddah. 相似文献
19.
Rosane G. Collevatti Raquel Estolano Silmara F. Garcia John D. Hay 《Tree Genetics & Genomes》2009,6(4):555-564
We investigated pollen dispersal and breeding structure in the tropical tree species Caryocar brasiliense Camb. (Caryocaraceae), using genetic data from ten microsatellite loci. All adult trees (101) within a patch of 8.3 ha were
sampled, and from these adults 18 open-pollinated maternal progeny arrays were analyzed (280 seeds from 265 fruits). Most
fruits presented only one seed (median equal to 1.000) and mean number of ripened seeds per fruit was 1.053 (SD = 0.828).
Our results showed that C. brasiliense presents a mixed-mating system, with 11.4% of self-pollination, multilocus outcrossing rate of t
m = 0.891 ± 0.025, and high probability of full-sibship within progeny arrays (r
p = 0.135 ± 0.032). Outcrossing rate and self-pollination varied significantly among mother trees. We could detect a maximum
pollen dispersal distance of ∼500 m and a mean pollen dispersal distance of ∼132 m. However, most pollination events (80%)
occurred at distances less than 200 m. Our results also indicated that pollen dispersal is restricted to a neighborhood of
5.4 ha with rare events of immigration (∼1% N
e
m = 0.35). C. brasiliense also presents a significant but weak spatial genetic structure (Sp = 0.0116), and extension of pollen dispersal distance was greater than seed dispersal (N
b = 86.20 m). These results are most likely due to the foraging behavior of pollinators that may have limited flight range.
The highly within-population synchronous flowering, high population density, and clumped distribution reinforce pollinator
behavior and affect residence time leading to a short-distance pollen dispersal. 相似文献
20.
Ole Rintek Madsen Ulrik Birk Lauridsen Andreas Hartkopp Ole Helmer S?rensen 《European journal of applied physiology and occupational physiology》1997,75(3):239-245
Dual energy x-ray absorptiometry (DEXA) offers the possibility of assessing regional soft tissue composition, i.e. lean mass (LM) and fat
mass : LM may be considered a measure of muscle mass. We examined age-related differences in LM, percentage fat (%fat) and
muscle strength in 100 healthy non-athletic women aged 18–87 years. Relationships between muscle strength and leg LM in 20
elite female weight lifters and in 18 inactive women with previous hip fractures were also studied. The LM and %fat of the
whole body, trunk, arms and legs were derived from a whole body DEXA scan. Isokinetic knee extensor strength (KES) and flexor
strength (KFS) at 30° · s–1 were assessed using an isokinetic dynamometer. The women aged 71–87 years had 35% lower KES and KFS than the women aged 18–40
years (P < 0.0001). Differences in LM were less pronounced. The LM of the legs, for instance, was 15% lower in the old than in the
young women (P < 0.0001). In a multiple regression analysis with age, body mass, height and leg LM or KES as independent variables and KES
or leg LM as the dependent variable, age was the most important predictor of KES (r
partial = −0.74, P < 0.0001). The same applied to KFS. Body mass, not age, was the most important predictor of leg LM (r
partial = 0.65, P < 0.0001) and of LM at all other measurement sites. The LM measured at different regions decreased equally with increasing
age. The KES:leg LM ratio was negatively correlated with age (r = −0.70, P < 0.0001). The weight lifters had significantly higher KES:leg LM ratios than age-matched controls (+12%, P < 0.0001) and vice versa for the women with previous hip fractures (–36%, P < 0.0001). In conclusion, from our study it would seem that in healthy nonathletic women, age is a more important determinant
of muscle strength than is LM as measured by DEXA. Muscle strengthening exercises and inactivity seem to have a considerably
stronger influence on muscle strength than on LM.
Accepted: 27 August 1996 相似文献