首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Availability of Zn to plant is hampered by its immobile nature and adverse soil conditions. Thus, Zn deficiency is observed even though high amount is available in soil. Root-shoot barrier, a major controller of zinc transport in plant is highly affected by changes in the anatomical structure of conducting tissue and adverse soil conditions like pH, clay content, calcium carbonate content, etc. Zn deficiency results in severe yield losses and in acute cases plant death. Zn deficiency in edible plant parts results in micronutrient malnutrition leading to stunted growth and improper sexual development in humans. To overcome this problem several strategies have been used to enrich Zn availability in edible plant parts, including nutrient management, biotechnological tools, and classical and molecular breeding approaches.  相似文献   

2.
Low micronutrient intake is implicated in a diversity of human health problems, ranging from problems associated with food insufficiency to those associated with food over-consumption. Humans are members of the order primates, suborder anthropoidea, and are most closely related to the great apes. Humans and apes are remarkably similar biologically. In the wild, apes and monkeys consume diets composed largely of plant foods, primarily the fruits and leaves of tropical forest trees and vines. Considerable evidence indicates that the ancestral line giving rise to humans (Homo spp.) was likewise strongly herbivorous (plant-eating). The wild plant parts consumed by apes and monkeys show moderate to high levels of many minerals and vitamins. The estimated daily intake of specific minerals, vitamin C and some other vitamins by wild primates is often quite high in comparison to intake levels of these same micronutrients recommended for humans. Are the high micronutrient intakes of wild primates simply a non-functional, unavoidable by-product of their strongly plant-based diets or might they actually be serving important as yet undetermined immunological or other beneficial functions? A better understanding of the basis for this apparent difference between humans and wild primates could help to clarify the range and proportions of micronutrients best suited for optimal human development, health and longevity.  相似文献   

3.
4.
Lethargy, poor attention, and the high rate and severity of infections in malnourished children affect their educational achievement. We therefore studied the association between visuomotor abilities and intelligence quotient (IQ) and their relationship with iron, zinc, and copper. A cross-sectional study was carried out on a sample of 89 healthy children (age range, 4-10 years). Evaluations of visuomotor ability and IQ were performed with the Developmental Test of Visual Motor Integration (VMI) and the Scale for Measurement of Intelligence for children aged 3-18 years, respectively. Nutritional status was assessed using anthropometry and biochemical assessments, which included serum ferritin, zinc and copper levels, and Hb. The sample was classified as having low or normal VMI scores: 47 children (52.8%, mean age 7 +/- 1.5 years) had low VMI, and 42 (47.2%, mean age 7 +/- 2.06 years) had normal VMI. There were no statistically significant differences in socioeconomic and cultural condition between both groups. We found significantly higher serum copper and ferritin levels in normal as compared to low VMI, but we did not find any differences with zinc. IQ was significantly higher in normal vs low VMI children. The fact that children with abnormal VMI presented low mean serum copper and ferritin concentrations could indicate that copper and iron deficiencies in this sample could be related with visuomotor abilities.  相似文献   

5.

Background

Multiple micronutrient deficiencies are highly prevalent among preschool children and often lead to anemia and growth faltering. Given the limited success of supplementation and health education programs, fortification of foods could be a viable and sustainable option. We report results from a community based double-masked, randomized trial among children 1–4 years evaluating the effects of micronutrients (especially of zinc and iron) delivered through fortified milk on growth, anemia and iron status markers as part of a four group study design, running two studies simultaneously.

Methods and Findings

Enrolled children (n = 633) were randomly allocated to receive either micronutrients fortified milk (MN = 316) or control milk (Co = 317). Intervention of MN milk provided additional 7.8 mg zinc, 9.6 mg iron, 4.2 µg selenium, 0.27 mg copper, 156 µg vitamin A, 40.2 mg vitamin C, and 7.5 mg vitamin E per day (three serves) for one year. Anthropometry was recorded at baseline, mid- and end-study. Hematological parameters were estimated at baseline and end-study. Both groups were comparable at baseline. Compliance was over 85% and did not vary between groups. Compared to children consuming Co milk, children consuming MN milk showed significant improvement in weight gain (difference of mean: 0.21 kg/year; 95% confidence interval [CI] 0.12 to 0.31, p<0.001) and height gain (difference of mean: 0.51 cm/year; 95% CI 0.27 to 0.75, p<0.001). Mean hemoglobin (Hb) (difference of 13.6 g/L; 95% CI 11.1 to 16.0, p<0.001) and serum ferritin levels (difference of 7.9 µg/L; 95% CI 5.4 to 10.5, p<0.001) also improved. Children in MN group had 88% (odds ratio = 0.12, 95% CI 0.08 to 0.20, p<0.001) lower risk of iron deficiency anemia.

Conclusions/Significance

Milk provides an acceptable and effective vehicle for delivery of specific micronutrients, especially zinc and iron. Micronutrient bundle improved growth and iron status and reduced anemia in children 1–4 years old.

Trial Registration

ClinicalTrials.gov NCT00255385  相似文献   

6.
Basal medium constituents and their concentration play an important role in growth and morphogenesis of plant tissues cultured in vitro. In this study effect of different inorganic nutrients (CoCl2, MnSO4, ZnSO4, CuSO4 and AgNO3) on callus induction and plant regeneration in Paspalum scrobiculatum and Eleusine coracana was examined. A 5× and 3× increase in regeneration response at enhanced levels of CuSO4 was noted for kodo and finger millets, respectively. Significant improvement in plant regeneration was also observed with the increase in levels of Co and Mn. Addition of AgNO3 to the basal medium also had a stimulatory effect on callus induction and plant regeneration. Optimization of nutrient level in the basal medium has highly significant role in obtaining maximum regeneration response from explants and callus culture.  相似文献   

7.
A link between biological and human sciences may be established, under the condition that we should admit the existence of reciprocal influences between them. The model for the regulation of agonistic antagonistic couples (MRAAC) is built from the study of biological systems and gives rise to specific types of control. This model can be helpful in decision processes in some human sciences such as management, economical and political strategies. The reason for such an opportunity lies in the fact that MRAAC is a general and phenomenological model able to incorporate the whole of the agonistic antagonistic systems. This type of regulation might be related to the concept of the viability of a system (yet also valid for human science systems) and to a functional and structural pattern which is the basis for agonistic antagonistic networks.  相似文献   

8.
Changes in cytosolic free Ca2+ concentration ([Ca2+]c) play a crucial role in the control of insulin secretion from the electrically excitable pancreatic β-cell. Secretion is controlled by the finely tuned balance between Ca2+ influx (mainly through voltage-dependent Ca2+ channels, but also through voltage-independent Ca2+ channels like store-operated channels) and efflux pathways. Changes in [Ca2+]c directly affect [Ca2+] in various organelles including the endoplasmic reticulum (ER), mitochondria, the Golgi apparatus, secretory granules and lysosomes, as imaged using recombinant targeted probes. Because most of these organelles have specific Ca2+ influx and efflux pathways, they mutually influence free [Ca2+] in the others. In this article, we review the mechanisms of control of [Ca2+] in various compartments and particularly the cytosol, the endoplasmic reticulum ([Ca2+]ER), acidic stores and mitochondrial matrix ([Ca2+]mito), focusing chiefly on the most important physiological stimulus of β-cells, glucose. We also briefly review some alterations of β-cell Ca2+ homeostasis in Type 2 diabetes.  相似文献   

9.
Epidemiologic studies indicate that the incidence of gastric cancer is higher in males than in females. Although the mechanisms mediating this difference are unclear, a role for estrogens has been proposed. We used Western blotting to evaluate the role of estrogen receptor (ER) subtypes ERα and ERβ and proliferating cell nuclear antigen (PCNA) in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis in Wistar rats; ERα and ERβ mRNA levels also were analyzed by quantitative real-time RT-PCR analysis. The incidence of gastric cancer was significantly higher in male than female rats. In both sexes, ERα expression was similar in MNNG-treated cancerous and noncancerous tissues and normal gastric tissue. However, ERβ expression in MNNG-treated cancerous and noncancerous tissues was significantly lower in male rats and higher in female rats than that in normal gastric tissue; MNNG-induced cancerous tissue showed the highest ERβ expression. PCNA expression in MNNG-treated cancerous tissues was higher than that in noncancerous tissues, and was higher in male rats than female rats. Western blotting results were consistent with the mRNA changes determined by quantitative real-time RT-PCR. The present study provides evidence of a sex-associated difference in ERβ and PCNA expression in MNNG-induced gastric cancers in Wistar rats.  相似文献   

10.
11.
Cisplatinum [cis-diamminedichloroplatinum(II)] is one of the most active antitumour agents and its effect is mainly due to the formation of cisplatinum-DNA crosslinks. Formation of cisplatinum-DNA intrastrand crosslinks in nucleated white blood cells of patients was measured, both in (pretreatment) samples exposed in vitro and in cells collected immediately after in vivo exposure to cisplatinum. Large interpatient variations were found. The in vitro results showed a linear correlation with the in vivo data (cc = 0.91). The in vitro measurements of crosslinks may allow prediction of response and avoidance of toxicity in individual patients.  相似文献   

12.
13.
The aim of the study was to investigate theAmbrosia pollen concentrations inselected Polish cities and for Kraków torelate it to some meteorological factors.Sampling was carried out in Kraków in1982–1997 and in Rabka in 1992–1996 with theuse of the gravimetric method. In Zakopane,Kraków, Ostrowiec witokrzyski,Warszawa and Pozna in 1995–1996 both thegravimetric and volumetric methods (Burkardtrap) were employed. In Kraków themonitoring has been performed since 1994 usingthe volumetric method. The results show theragweed pollen presence in August and Septemberwith the tendency to appear more frequently inAugust in some years. In Kraków (1994–1999)Ambrosia pollen was found either in thelast two weeks of August or in the first twoweeks of September which seems to be a regularand repeatable pattern every two years.Seasonal fluctuations of Ambrosia pollenconcentration do not show a clear increasingtendency except at Warszawa and Ostrowiecwitokrzyski in 1996 and at Krakówin 1999. Percentage of Ambrosia pollen inannual sums of total pollen is very low anddoes not exceed 1% except at Ostrowiecwitokrzyski in 1996 (1.2%) and atKraków in 1999 (2%). For Kraków theanalysis of some meteorological factors (Tmax,Tmin, precipitation, wind direction) wasperformed. High temperature and lack of rain orlow precipitation correlate well with ragweedpollen concentrations. During the Ambrosia pollen seasons ESE, E, S, SE, WSW, SWwind directions prevailed which could suggest along-distance transport from Ukraine, the CzechRepublic, Slovakia and also from Hungary, one ofthe most ragweed-polluted countries.  相似文献   

14.
Cisplatinum [cis-diamminedichloroplatinum(II)] is one of the most active antitumour agents and its effect is mainly due to the formation of cisplatinum-DNA crosslinks. Formation of cisplatinum-DNA intrastrand crosslinks in nucleated white blood cells of patients was measured, both in (pretreatment) samples exposed in vitro and in cells collected immediately after in vivo exposure to cisplatinum. Large interpatient variations were found. The in vitro results showed a linear correlation with the in vivo data (cc=0.91). The in vitro measurements of crosslinks may allow prediction of response and avoidance of toxicity in individual patients.  相似文献   

15.
We tested if variations (i.e., breadth) in morphology and habitat use vary predictably among six aquatic gastropod species that were collected across Indiana and Illinois, USA. We predicted that interspecific morphological variation would positively covary with variation in habitat use among species. We used geometric morphometrics (Procrustes technique and relative warp analysis) to quantify morphology and multivariate analyses (PCA) to quantify habitat. Increased morphological breadth did not vary predictably with increased habitat breadth. However, we found that life history traits correspond with patterns in morphological and habitat breadth for these six aquatic gastropods. Pulmonate gastropods (use lungs for respiration) that lack an operculum cover exhibited decreased morphological breadth compared to coenogastropods (use gills for respiration). This pattern may ultimately be a function of behavioral adaptations in freshwater gastropods. Gastropods that are capable of breathing air or using other behavioral modifications such as burrowing to escape predators may not require high morphological breadth. Conversely, selection may favor higher morphological breadth in gastropods with gills that also do not move out of the water column to escape predators.  相似文献   

16.
We have previously shown that 4 wk of exercise training early in life normalizes the otherwise greatly reduced pancreatic β-cell mass in adult male rats born small. The aim of the current study was to determine whether a similar normalization in adulthood of reduced skeletal muscle mitochondrial biogenesis markers and alterations in skeletal muscle lipids of growth-restricted male rats occurs following early exercise training. Bilateral uterine vessel ligation performed on day 18 of gestation resulted in Restricted offspring born small (P < 0.05) compared with both sham-operated Controls and a sham-operated Reduced litter group. Offspring remained sedentary or underwent treadmill running from 5-9 (early exercise) or 20-24 (later exercise) wk of age. At 24 wk of age, Restricted and Reduced litter offspring had lower (P < 0.05) skeletal muscle peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) protein expression compared with Control offspring. Early exercise training had the expected effect of increasing skeletal muscle markers of mitochondrial biogenesis, but, at this early age (9 wk), there was no deficit in Restricted and Reduced litter skeletal muscle mitochondrial biogenesis. Unlike our previous observations in pancreatic β-cell mass, there was no "reprogramming" effect of early exercise on adult skeletal muscle such that PGC-1α was lower in adult Restricted and Reduced litter offspring irrespective of exercise training. Later exercise training increased mitochondrial biogenesis in all groups. In conclusion, although the response to exercise training remains intact, early exercise training in rats born small does not have a reprogramming effect to prevent deficits in skeletal muscle markers of mitochondrial biogenesis in adulthood.  相似文献   

17.
Because previous research has shown a relationship between maximal squat strength and sprint performance, this study aimed to determine if changes in maximal squat strength were reflected in sprint performance. Nineteen professional rugby league players (height = 1.84 ± 0.06 m, body mass [BM] = 96.2 ± 11.11 kg, 1 repetition maximum [1RM] = 170.6 ± 21.4 kg, 1RM/BM = 1.78 ± 0.27) conducted 1RM squat and sprint tests (5, 10, and 20 m) before and immediately after 8 weeks of preseason strength (4-week Mesocycle) and power (4-week Mesocycle) training. Both absolute and relative squat strength values showed significant increases after the training period (pre: 170.6 ± 21.4 kg, post: 200.8 ± 19.0 kg, p < 0.001; 1RM/BM pre: 1.78 ± 0.27 kg·kg(-1), post: 2.05 ± 0.21 kg·kg(-1), p < 0.001; respectively), which was reflected in the significantly faster sprint performances over 5 m (pre: 1.05 ± 0.06 seconds, post: 0.97 ± 0.05 seconds, p < 0.001), 10 m (pre: 1.78 ± 0.07 seconds, post: 1.65 ± 0.08 seconds, p < 0.001), and 20 m (pre: 3.03 ± 0.09 seconds, post: 2.85 ± 0.11 seconds, p < 0.001) posttraining. Whether the improvements in sprint performance came as a direct consequence of increased strength or whether both are a function of the strength and power mesocycles incorporated into the players' preseason training is unclear. It is likely that the increased force production, noted via the increased squat performance, contributed to the improved sprint performances. To increase short sprint performance, athletes should, therefore, consider increasing maximal strength via the back squat.  相似文献   

18.

Background

The value of genotyping to predict variant phenotypes in patients with phenylalanine hydroxylase (Pah) deficiency is a matter of debate. However, there exists no comprehensive population relationship study focused on the Han Chinese.

Methods

We analyzed genotype–phenotype correlation for 186 different genotypes in 338 unrelated Chinese patients harboring 109 different Pah mutations. Two systems were used in this process. The first was a phenotype prediction system based on arbitrary values (AV) attributed to each mutation. The second was a pair-wise correlation analysis. The observed phenotype for AV analysis was the corresponding metabolic phenotype stratified according to the pretreatment phenylalanine (Phe) value.

Results

We found that the observed phenotype matched the predicted phenotype in 54.41% of 272 patients for whom AV information was available; the highest degree of concordance (61.83%) was found in patients with null/null genotypes, whereas the lowest “concordance rate” (32.69%) was observed for patients with expected mild-PKU phenotype. There are repeated inconsistencies for such mutations as R241C, R243Q, R261Q, V388M, V399V, R408Q, A434D and EX6-96A>G which are associated with variable phenotypes in patients with identical genotype. Significant correlations were disclosed between pretreatment Phe values and predicted residual activity (r = − 0.45643, P < 0.0001) or AV sum (r = − 0.59523, P < 0.0001).

Conclusion

Our study supports the notion that the Pah mutation genotype is the main determinant of metabolic phenotype in most patients in a particular population, and provided novel insights into the values that underpin the subsequent treatment and the prognosis of PKU in Chinese.  相似文献   

19.
Four hectares were inventoried for all trees with diameter at breast height (DBH) of 10cm or greater in a terra firme forest 200km Northeast of Manaus, Central Amazonia. The number of species varied from 137 to 168, the number of individuals from 639 to 713, total basal area from 32.8 to 40.2 and total biomass from 405 to 560 tons per hectare. The majority of trees, 90%, had a DBH between 10 and 30 cm. Leguminosae, Lauraceae, Sapotaceae, Chrysobalanaceae and Moraceae were the most rich families (number of species) in all sampled hectares. The most abundant families in all sampled hectares (number of trees) were Leguminosae, Burseraceae, Myristicaceae, Moraceae and Chrysobalanaceae. The most dominant families in all sampled hectares (basal area and biomass) were Leguminosae, Lecythidaceae, Chrysobalanaceae, Bombacaceae and Moraceae. Similarity indexes at family level varied from 67 to 86% between the four hectares sampled. Alexa grandiflora (Leguminosae) was the most abundant species in the hectares one and three, while Scleronema micranthum (Bombacaceae), and Oenocarpus bacaba (Palmae) were the most abundant species in hectares two and four. S. micranthum was the most dominant species (basal area) in hectares one and two, while Bertholletia excelsa (Lecythidaceae) and Goupia glabra (Celastraceae) were the most dominant species in hectares three and four. S. micranthum (Bombacaceae), Buchenavia sp. 2 (Combretaceae), B. excelsa (Lecythidaceae) Couepia obovata (Chrysobalanaceae) were the most dominant species (biomass) in hectares one to four, respectively. Similarity indexes at species level varied from 26 to 44% between the four sampled hectares. This inventory is compared with previous studies and it was found that, in our study area, there was a greater proportion of trees of 60cm diameter or more and consequently a considerably higher total basal area. It is concluded that there are still an inadequate number of inventories of Amazonian terra firme forests to elucidate the major floristic pattern a both regional and local levels. Since the area is a mosaic of distinct floristic communities it is essential to obtain further standardized inventory data in order to set adequate conservation policies for the region.  相似文献   

20.
The hippocampus plays a key role in declarative learning and memory [1]. Hippocampal long-term potentiation (LTP) is a type of synaptic plasticity that has been widely studied as a syn-aptic mechanism underlying learning and memory[27]. It has been reported that in vitro LTP in area CA1 is subjected to b-adrenergic modulation. For example, the theta-pulse stimulation (510 Hz), a neutral frequency not modifying synaptic strength, can elicit a robust LTP in area CA1 in slice when the b-adr…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号