In Vitro Cellular & Developmental Biology - Plant - Plants that produce bioactive chemicals provide a viable in vitro method for producing key nutraceutical substances, especially in the... 相似文献
The entire absorbance vs. time curve of a sample of germinating bacterial spores can be accurately described by a model which considers that the spores rate of entry into the phase initiation of germination is determined by transitions between three spore states. The first of these transitions is easily identified with the triggering event, while the existence of the intermediate state, and its identification with the triggered spore, can be established from theoretical as well as experimental considerations. The observed sample lag time is seen to arise from the position of the measured event in the single spore in the sequence of indices of germination. Consideration that the single spore may effect the measured change in a complex way over a finite interval of time leads to a mathematical formulation of our model which can describe the germination process whatever the endpoint chosen for its observation. 相似文献
Spring-born female lambs require a decrease in day length for the normal timing of puberty the following autumn. If this decrease occurs early in postnatal life (i.e. 0-10 weeks), puberty is delayed. This study tested the hypothesis that failure of the neonatal lamb to respond to the critical long-day to short-day signal is due to inadequate nocturnal melatonin secretion. The approach was to artificially increase, to adult levels, the low nighttime rises of melatonin during the early postnatal period. Eight female lambs served as controls; they were raised on short days until 17 wk of age, and then exposed to 5 wk of long days, after which they were returned to short days. This alternating sequence of photoperiods during mid-development would be expected to induce normal puberty. Sixteen experimental females were exposed to the critical block of long days much earlier; they were placed in long days between 2 and 7 wk of age and in short days thereafter. Half (n = 8) received no further treatment. The other half (n = 8) were infused nightly with melatonin during the 8-h dark phase of the 5-wk, long-day photoperiod. This increased the amplitude of the natural nighttime melatonin rises 3- to 4-fold, well into the adult range.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
The musculoskeletal structures of the thoracic wall and the neck are a relatively common source of chest pain. Pain arising from these structures is often mistaken for angina pectoris, pleurisy or other serious disorders. In this article the clinical features, pathogenesis and management of the various musculoskeletal chest wall disorders are discussed. The more common causes are costochondritis, traumatic muscle pain, trauma to the chest wall, “fibrositis” syndrome, referred pain, psychogenic regional pain syndrome, and arthritis involving articulations of the sternum, ribs and thoracic spine. Careful analysis of the history, physical findings and results of investigation is essential for precise diagnosis and effective treatment. 相似文献
The presence of fluoride in drinking water can be either beneficial or harmful for human health, depending on its concentration. Most adverse effects of fluoride are observed at high concentrations (above 1.5 mg/L). This study was aimed to evaluate the effect of fluoride concentrations in drinking water on spontaneous abortion in two regions: one with low fluoride concentration and another with high fluoride concentration. The results showed that there is a relationship between the concentration of fluoride in drinking water and abortion, so that the risk of abortion increased at high concentrations of fluoride. However, further studies are needed to clarify this relationship due to the small area and population in this study. 相似文献
Summary The Upper Cretaceous exposures in east central Sinai are represented by carbonate-dominated successions interbedding few sandstone,
chert, shale and marl horizons. The recognised rock units are correlated with their counterparts commonly used in the Gulf
of Suez region and central Sinai including from base to top: the Raha Formation, Abu Qada Formation, Wata Formation, Matulla
Formation and the Sudr Chalk.
Twelve limestone microfacies are encountered and are categorised as mudstones (pelmicrite and ostracod micrite), wackestones
(pelagic biomicrite and foraminiferal biomicrite), grainstones (foraminiferal biopelsparite and oosparite), boundstones (bindstone
and framestone), floatstones (coated-grained biomicrudite, rudist biomicrudite and shelly biomicrudite) and rudstones (shelly
biosparudite). The dolostone microfacies include fine-medium crystalline ostracod dolostones and shelly dolostones. These
microfacies have been compared with the Standard Microfacies Types and their depositional environments are discussed.
The encountered litho- and biofacies suggest that the Cenomanian shallow transgressive sea had covered east central Sinai
as far south as the Dahab region. By the advent of the Turonian, open marine subtidal conditions prevailed. This was followed
by transitional conditions with shoals and tidal bars in the Late Turonian pointing to a regressive phase more pronounced
at the southern localities. The rocks of the Matulla Formation were deposited in an oscillating environment of shallow subtidal
to intertidal conditions during Coniacian-Santonian. In the Late Santonian and during most of the Campanian-Maastrichtian,
sedimentation was influenced by open marine conditions with low sedimentation rates; local shallow subtidal regressive events
occurred. 相似文献
Background and objective: The aim of the present study was to develop and examine a new non-invasive injectable graft for the repair of alveolar bone clefts using recombinant human bone morphogenetic protein-2 (rhBMP-2) encapsulated within injectable liposomal in situ gel (LIG).
Method: Different liposomal formulations loaded with rhBMP-2 were prepared, and the effects of the preparation methods and lipid content on the efficiency of rhBMP-2 encapsulation within the liposomes were studied. For the preparation of in situ gel, deacetylated gellan gum (DGG) was used, and the in vitro gelation characteristics of the gel were evaluated. In vivo pharmacokinetics and histology were also assessed. Critical size alveolar defects were surgically created in the maxillae of 30 New Zealand rabbits and treated with different injectable formulae, including rhBMP-2 liposomes and in situ gel (rhBMP-2-LIG).
Results: The results indicated that the prepared rhBMP-2-LIG prolonged the release and residence time of BMP-2 within rabbits for more than 7 days. Histomorphometric assessment showed 67% trabecular bone filling of the defects treated using this novel formula.
Conclusion: BMP-2-LIG is a promising delivery device for the repair of alveolar bone defects associated with cleft deformities. 相似文献
Currently, alternate plasticizers are used to replace phthalate plasticizers in children’s toys, medical equipments and food packaging, due to the adverse effects of phthalate compounds on human health and laws prohibiting their use. Current information regarding the safety and potential adverse effects of alternate plasticizers is limited and recent studies have found alternate plasticizers to display similar characteristics to those observed in phthalate plasticizers. This study was undertaken to evaluate and predict the potential endocrine disrupting activity of the three most commonly used alternate plasticizers: di(2-ethylhexyl)terephthalate (DEHT), tris(2-ethylhexyl)trimellitate (TOTM), and diisononyl hexahydrophthalate (DINCH) against human sex hormone-binding globulin (SHBG) using in silico approaches.
Materials and methods
The crystal structure of human SHBG (Id: 1D2S) was retrieved from Protein Data Bank. PubChem database was searched for the structures of alternate plasticizers, DEHT, TOTM, and DINCH. Docking was performed using Glide (Schrodinger) Induced Fit Docking module.
Results
Induced Fit Docking of three alternate plasticizer compounds indicated that each of the three compounds fitted well into the steroid binding pocket of SHBG. Docking displays showed interactions of alternate plasticizers with 25–30 amino-acid residues of SHBG; 18–20 amino residues overlapped between the natural ligand, DHT, and the three compounds (commonality of 82–91 %). The hydrogen-bonding interaction of the amino-acid residue, Asn-82, of SHBG was also present in displays of DHT and all the three alternate phthalates. The binding affinity of all the three alternate phthalates was higher than DHT; maximum in DINCH followed by TOTM and DEHT.
Conclusion
Our results suggested that the three alternate plasticizers have potential to engage the important interacting residues of SHBG and thus interfere in its steroid homeostatic function.
Drought imposes a major constraint over the productivity of wheat, particularly in arid and semi-arid production zones. Here, the genetic basis of spectral reflectance indices was investigated in drought-stressed wheat by comparing, under two contrasting moisture regimes, the performance of an F6 recombinant inbred line (RIL) population bred from a cross between the drought tolerant cultivar Pavon76 and the sensitive cultivar Yecora Rojo. The parents and RILs were genotyped with respect to both a set of microsatellite (SSR) loci and a number of known drought-responsive genes. In all, 28 quantitative trait loci (QTL) controlling dry weight per plant, water content of the above-ground biomass, leaf water potential, canopy temperature, and spectral reflectance indices traits were identified. The loci were distributed over 11 chromosomes, belonging to each of the three wheat sub-genomes. There were important location-flanking markers Barc109 and Barac4 on chromosome 5B relating to dry weight per plant accumulation under the limited irrigation regime. The same region-harbored QTL associated with leaf water potential, canopy temperature, and ratio index under the limited irrigation regime. Linkage between the known drought-responsive genes and aspects of the drought response was established. Some of QTL were of substantial enough effect for their linked markers to be likely usable for the marker-assisted breeding of drought tolerance in wheat. 相似文献