Geographical and ethnic variation of the 677C>T allele of 5,10 methylenetetrahydrofolate reductase (MTHFR): findings from over 7000 newborns from 16 areas world wide.
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Alleles↗
Biomedical subjects
Z Li
Publications and source records attributed to Z Li.
The sugary-type isoamylase gene from rice and Aegilops tauschii: characterization and comparison with maize and arabidopsis.
Genes for an isoamylase-like debranching enzyme have been isolated from rice and Aegilops tauschii, the donor of the D genome to wheat. The structures of the genes are very similar to each other and to the maize SU1 isoamylase gene and consist of 18 exons spread over approximately 7.5 kb. Southern analysis and fluorescent in situ hybridization showed the Ae. tauschii gene to be located in the proximal region of the short arm of chromosome 7D, thus showing synteny with the localization of the rice isoamylase gene on rice chromosome 8. Analysis of the expression pattern of wheat sugary isoamylase genes indicates that they are strongly expressed in the developing endosperm 6 days after flowering. Three distinct Sugary-type cDNA sequences were isolated from the wheat endosperm that are likely to correspond to the products of the three genomes. The deduced amino acid sequence of rice and wheat Sugary-type isoamylase is compared with other sequences available in the database and the results demonstrate that there are three types of isoamylase sequences in plants: those containing 18 exons (the Sugary-type isoamylase gene), those containing 21 exons, and those containing only 1 exon. It is possible that different combinations of isoamylase genes are expressed in different tissues.
Amino Acid Sequence↗
Segmental allotetraploidy and allelic interactions in buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.) as revealed by genome mapping.
Linkage analyses increasingly complement cytological and traditional plant breeding techniques by providing valuable information regarding genome organization and transmission genetics of complex polyploid species. This study reports a genome map of buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.). Maternal and paternal maps were constructed with restriction fragment length polymorphisms (RFLPs) segregating in 87 F1 progeny from an intraspecific cross between two heterozygous genotypes. A survey of 862 heterologous cDNAs and gDNAs from across the Poaceae, as well as 443 buffelgrass cDNAs, yielded 100 and 360 polymorphic probes, respectively. The maternal map included 322 RFLPs, 47 linkage groups, and 3464 cM, whereas the paternal map contained 245 RFLPs, 42 linkage groups, and 2757 cM. Approximately 70 to 80% of the buffelgrass genome was covered, and the average marker spacing was 10.8 and 11.3 cM on the respective maps. Preferential pairing was indicated between many linkage groups, which supports cytological reports that buffelgrass is a segmental allotetraploid. More preferential pairing (disomy) was found in the maternal than paternal parent across linkage groups (55 vs. 38%) and loci (48 vs. 15%). Comparison of interval lengths in 15 allelic bridges indicated significantly less meiotic recombination in paternal gametes. Allelic interactions were detected in four regions of the maternal map and were absent in the paternal map.
Alleles↗
The noradrenergic system of aged GDNF heterozygous mice.
Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor for noradrenergic (NE) neurons of the pontine nucleus locus coeruleus (LC). Decreased function of the LC-NE neurons has been found during normal aging and in neurodegenerative disorders. We have previously shown that GDNF participates in the differentiation of LC-NE neurons during development. However, the continued role of GDNF for LC-NE neurons during maturation and aging has not been addressed. We examined alterations in aged mice that were heterozygous for the GDNF gene (Gdnf+/-). Wild-type (Gdnf+/+) and Gdnf+/- mice (18 months old) were tested for locomotor activity and brain tissues were collected for measuring norepinephrine levels and uptake, as well as for morphological analysis. Spontaneous locomotion was reduced in Gdnf+/- mice in comparison with Gdnf+/+ mice. The reduced locomotor activity of Gdnf+/- mice was accompanied by reductions in NE transporter activity in the cerebellum and brain stem as well as decreased norepinephrine tissue levels in the LC. Tyrosine hydroxylase (TH) immunostaining demonstrated morphological alterations of LC-NE cell bodies and abnormal TH-positive fibers in the hippocampus, cerebellum, and frontal cortex of Gdnf+/- mice. These findings suggest that the LC-NE system of Gdnf+/- mice is impaired and suggest that GDNF plays an important role in continued maintenance of this neuronal system throughout life.
Aging↗
Investigation of the effectiveness of source control sanitation concepts including pre-treatment with Rottebehaelter.
High levels of nutrients recovery can be achieved with source control sanitation--technologies are already available. Separation toilets for example separate urine that can be used in agriculture with some crop restrictions as a fertiliser after about 6 months of storage. The grey water has very low loads of nitrogen and can be treated in different combinations of biological and physical treatment and reused. Faecal matter with flush water from the separation toilet can be discharged into Rottebehaelter (an underground pre-composting tank) that retains solid material and drains liquid to a certain extent. Investigation of Rottebehaelter in the different sites and laboratory experiments showed that retained faecal material still contained a high percentage of water. However, odour was not noticed in those Rottebehaelters that have been examined. One of the major advantages of this system over other forms of pre-treatment as the septic tanks is that it does not deprive agriculture of the valuable nutrients and soil conditioner from human excreta. It has to be stated that maintenance is a crucial factor. As an intermediate result of the intensive research of Rottebehaelter it seems that these systems are rather a way of solids retaining, de-watering and long-term storage before the contents are further treated.
Agriculture↗
Greywater treatment by constructed wetlands in combination with TiO2-based photocatalytic oxidation for suburban and rural areas without sewer system.
In this study greywater treatment through constructed wetlands and subsequently through TiO2-based photocatalytic oxidation was investigated. Through constructed wetlands treatment the organic substances have been reduced greatly. For further removal of organic substances and pathogens, a TiO2-based photocatalytic oxidation process was used subsequently. The results showed that the treated greywater through constructed wetlands and subsequent through TiO2-based photocatalytic oxidation with short irradiation time (3 hours irradiation time) met the requirements of European bathing water quality easily. Therefore, the greywater treated with the processes combination can directly be reused for non-potable purposes. Moreover, since residual organic substances through TiO2-based photocatalytic oxidation with long irradiation time can be eliminated almost totally, it is also possible that treated greywater is used for groundwater recharge as a drinking water resource.
Biodegradation, Environmental↗
Pre-treatment of domestic wastewater with pre-composting tanks: evaluation of existing systems.
A relatively new technology called pre-composting tank or Rottebehaelter, retaining solid material and draining water to a certain extent, has been found to be an interesting component of decentralised systems to replace the usual septic tank. Results of the investigation revealed that solid material which has been retained in the pre-composting tanks still contained a high percentage of water. However, there was no odour problem at and near the tanks. The pre-composted materials have to be further composted together with household and garden wastes for a year prior to their use as soil conditioner. The filtrate is further treated in a constructed wetland. One of the major advantages of this system compared to other systems, such as septic tanks, is that it does not deprive agriculture of the valuable nutrients and soil conditioner from human excreta and does not require an expensive tanker truck. It can be the most appropriate system for application in regions where there is a demand for local reuse of the end product. It has to be stated that maintenance is a crucial factor.
Agriculture↗
Assessment of sustainable water management for rapidly developing urban regions in Guangzhou City, China.
The Shawan River will be the focal point in the development of the Panyu District, the southern-most district of Guangzhou City in the Guangdong Province of South China. In this research, through the use of two scenarios, the future water quality of the Shawan River was predicted with relation to changes in the water quantity utilized to fuel industrial and domestic development. The worst-case scenario used, simulated the situation if no wastewater treatment was employed, and the best-case scenario simulated the situation if 90% of the pollution load was removed. The period of simulation was for the years 2020 and 2050. Three flowrates were used in the evaluation, those of: the 90% probability of the month of lowest flow (37.2 m3/s); and the range of flowrates within the low flow period, that is, the dry season from November to February (307 and 432 m3/s). Subsequently, two countermeasures (industrial and domestic water savings)--sustainable initiatives--were nested within the two scenarios to ascertain improvements in water quality as a direct result of reduction in water quantity used. The industrial water saving countermeasure showed the greatest improvement in water quality. For the 90% probability of lowest flow for the worst-case scenario, this countermeasure equated to a 63% decrease in BOD. For the low flow period flowrates the background concentration of pollutants was more influential than improvements imparted by the countermeasures to the future predicted water quality. It was recommended that industrial countermeasures be used that take into account water saving, water recycling, the use of brackish water for cooling, and the implementation of economic pricing initiatives. Also that inter-district governmental policy initiatives be introduced to prevent upstream pollution from influencing downstream proposals, further enhancing sustainable water management of the Shawan River.
China↗
A potential role for gap junctions in breast cancer metastasis to bone.
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Journal Article↗
The efficacy and tolerability of risedronate once a week for the treatment of postmenopausal osteoporosis.
This study evaluated the efficacy and tolerability of risedronate once a week (35 mg and 50 mg) compared with risedronate 5 mg once daily in women with osteoporosis. We conducted a randomized, double-blind, active-controlled, 2-year study; the primary efficacy assessment was performed after 1 year. Subjects were women aged 50 years or older who had been postmenopausal for at least 5 years, with either a bone mineral density (BMD) T-score of -2.5 or lower (lumbar spine or proximal femur) or a T-score lower than -2 and at least one prevalent vertebral fracture. Subjects received risedronate 5 mg once daily, 35 mg once a week or 50 mg once a week. All subjects also received 1 g daily of elemental calcium supplementation and supplemental vitamin D if the baseline serum levels were low. The primary efficacy measure was percent change in lumbar spine BMD at 12 months. A total of 1,456 women were randomized and received medication; 1,209 (83%) women completed 12 months. The mean percent change (SE) in lumbar spine BMD after 12 months was 4.0% (0.2%) in the 5 mg daily group, 3.9% (0.2%) in the 35 mg group, and 4.2% (0.2%) in the 50 mg group; each once-a-week treatment was determined to be as effective as the daily treatment. Outcomes of the secondary efficacy measurements and safety assessments were also similar in all 3 groups after 12 months. Risedronate 35 mg and 50 mg once a week provide the same efficacy and safety as the daily 5 mg regimen; therefore, the lower dose, 35 mg once a week, is considered optimal for women with postmenopausal osteoporosis who desire a once-a-week regimen.
Administration, Oral↗
Passive stiffness changes in soleus muscles from desmin knockout mice are not due to titin modifications.
Passive stiffness was found to be increased in mouse soleus muscles lacking desmin. Because titin is considered to be the major source of muscle elasticity, the stiffening might be explainable by titin adaptation. To test this, passive mechanical properties of single skinned fibres of soleus muscles from desmin knockout and control mice were analysed by using various extension tests. Titin expression was studied by SDS-gel electrophoresis. Absence of desmin did not modify either electrophoretic mobility of the titin band (3700 kDa) or optical density-unit ratios between bands for titin and nebulin (congruent with 0.3) and bands for titin and myosin heavy chain (congruent with 0.08). Elastic properties of fibres were not altered in the absence of desmin since passive tensions were similar under quasi-static (56-66 kN m(-2)) and dynamic (100-118 kN m(-2)) conditions whatever the kind of fibre. Thus, titin is unlikely to be responsible for the large increase in passive stiffness observed in whole soleus muscles when desmin is lacking.
Animals↗
Direct patterning of modified oligonucleotides on metals and insulators by dip-pen nanolithography.
The use of direct-write dip-pen nanolithography (DPN) to generate covalently anchored, nanoscale patterns of oligonucleotides on both metallic and insulating substrates is described. Modification of DNA with hexanethiol groups allowed patterning on gold, and oligonucleotides bearing 5'-terminal acrylamide groups could be patterned on derivatized silica. Feature sizes ranging from many micrometers to less than 100 nanometers were achieved, and the resulting patterns exhibited the sequence-specific binding properties of the DNA from which they were composed. The patterns can be used to direct the assembly of individual oligonucleotide-modified particles on a surface, and the deposition of multiple DNA sequences in a single array is demonstrated.
Adsorption↗
Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor.
A change in 'symmetry' is often observed when matter undergoes a phase transition-the symmetry is said to be spontaneously broken. The transition made by underdoped high-transition-temperature (high-Tc) superconductors is unusual, in that it is not a mean-field transition as seen in other superconductors. Rather, there is a region in the phase diagram above the superconducting transition temperature Tc (where phase coherence and superconductivity begin) but below a characteristic temperature T* where a 'pseudogap' appears in the spectrum of electronic excitations. It is therefore important to establish if T* is just a cross-over temperature arising from fluctuations in the order parameter that will establish superconductivity at Tc (refs 3, 4), or if it marks a phase transition where symmetry is spontaneously broken. Here we report that, for a material in the pseudogap state, left-circularly polarized photons give a different photocurrent from right-circularly polarized photons. This shows that time-reversal symmetry is spontaneously broken below T*, which therefore corresponds to a phase transition.
Journal Article↗
Absence of a loss of in-plane infrared spectral weight in the pseudogap regime of Bi(2)Sr(2)CaCu(2)O(8+delta).
The ab-plane reflectance of Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi-2212) thin films was measured in the 30-25 000 cm(-1) range for one underdoped ( T(c) = 70 K), and one overdoped sample ( T(c) = 63 K) down to 10 K. We find similar behaviors in the temperature dependence of the normal-state infrared response of both samples. Above T(c), the effective spectral weight, obtained from the integrated conductivity, does not decrease when T decreases, so that no opening of an optical pseudogap is seen. We suggest that these are consequences of the pseudogap opening in the k = (0,pi) direction and of the in-plane infrared conductivity being mostly sensitive to the k = (pi,pi) direction.
Journal Article↗
Hearts from mice lacking desmin have a myopathy with impaired active force generation and unaltered wall compliance.
OBJECTIVE: Desmin intermediate filaments are key structures in the cytoskeleton of cardiac muscle. Since they are associated with Z-discs and intercalated discs, they may have a role in sarcomere alignment or force transmission. We have explored the mechanical function of the desmin filaments in the cardiac wall by comparing desmin-deficient (Des-/-) and wild-type (Des+/+) mice. METHODS: The Langendorff technique was used to examine the contractility of the whole heart. Rate of force generation, Ca(2+)-sensitivity and force per cross-sectional area were measured in skinned ventricle muscle preparations. RESULTS: Des-/- mice have a cardiomyopathy with increased heart weight. Diastolic pressure was increased at all filling volumes in the Des-/- group. Since passive wall stress (i.e. force per area) was unchanged, the alteration in diastolic pressure is a consequence of the thicker ventricle wall. Developed pressure, rate of pressure increase and developed wall stress were significantly reduced, suggesting that active force generation of the contractile apparatus is reduced in Des-/-. Concentrations of actin and myosin in the ventricle were unaltered. Measurements in skinned muscle preparations showed a lower active force development with unaltered Ca(2+)-sensitivity and rate of tension development. CONCLUSION: It is suggested that the intermediate filaments have a role in active force generation of cardiac muscle, possibly by supporting sarcomere alignment or force transmission. The desmin filaments do not contribute the passive elasticity of the ventricle wall. Des-/- mice provide a model for genetic cardiomyopathy where the main factor contributing to altered cardiac performance is a decrease in active force generation, possibly in combination with a loss of functional contractile units.
Actins↗
Force and deformation on branching rudiments: cleaving between hypotheses.
A mathematical model of the forces and deformations of the tissues involved in branching morphogenesis is developed and solved. The epithelium and mesenchyme are modeled as Stokes fluids separated by an interface. Each fluid is assumed to have constant viscosity. An initially 3-lobed rudiment is deformed by three inwardly directed point forces. Relationships between the physical parameters of the model (tissue viscosity, clefting force, surface tension) and the time course and morphology are explored. We find that the surface tension, clefting force, and viscosity ratio of the two tissues have significant effects on the branching. We conclude that epithelial branching in soft gels is fundamentally different from epithelial branching in mesenchyme, because of the different mechanics. We propose that a complete understanding of branching morphogenesis requires measurements of the mechanical aspects.
Animals↗
Models of skeletal muscle to explain the increase in passive stiffness in desmin knockout muscle.
Absence of desmin in skeletal muscle was found to induce an increase in passive stiffness. The present study aimed at developing rheological models of passive muscle to explain this stiffening. Models were elaborated by using experimental data depicting muscle viscoelastic behaviour. The experimental protocol included stepwise extension tests applied on control and desmin knockout soleus muscles from mice. Linear and non-linear models were composed of elastic and viscous elements. They were constructed with the aim at taking the presence or absence of desmin into account by simulating desmin as an elastic element. Furthermore, associated adaptation of connective tissues in absence of desmin was modelled as an additional elastic element. Differences in passive behaviour induced by absence of desmin were predicted by using a linear model and a non-linear one. The non-linear model was selected because: (1) it is able to predict experimental viscoelastic kinetics accounting for the increase in passive stiffness in muscles lacking desmin, (2) its design is consistent with morphological data, and (3) stiffness characteristics of its elements are in accordance with the literature. Finally, this modelling approach demonstrates that both absence of desmin and adaptation of connective tissue are required to explain the increase in passive stiffness in desmin knockout muscles.
Animals↗
Local immunosuppression with kidney-targeting prednisolone prodrug prolong rat renal allograft survival.
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Animals↗