排序方式: 共有74条查询结果,搜索用时 15 毫秒
51.
Tammy Smith Maria Escalona Terri Ryan Gordon K. Livingston Jacob T. Sanders Adayabalam S. Balajee 《Journal of cellular biochemistry》2019,120(5):8619-8629
Dicentric chromosome assay (DCA) is routinely used for estimating the absorbed radiation dose in exposed humans. Optimal lymphocyte viability is crucial for reliable dose estimation and most cytogenetic laboratories prefer the receipt of blood samples within 24 to 36 hours after collection. Delays in the shipment/receipt of samples can occur sometimes under certain unforeseen circumstances: (1) Adverse weather conditions, (2) distant location of blood collection sites, and (3) shipping and handling of a large number of samples after radiological/nuclear mass casualty incident(s). To circumvent some of these limitations, we evaluated the suitability of ex vivo irradiated blood samples stored in the presence of phytohemagglutinin (PHA) for 7 days at ambient temperature (22-24°C) for radiation biodosimetry. Blood samples stored in the presence of PHA for up to 7 days showed a higher mitotic index than blood samples stored without PHA. To verify the use of stored blood samples for DCA, frequencies of X-rays induced dicentric chromosomes were analyzed in the blood samples that were cultured either 24 hours after exposure or 7 days later after storage. Our results indicate that storage of ex vivo irradiated blood samples in the presence of PHA at ambient temperature was found optimal for DCA and that the radiation doses estimated by dicentric chromosome frequencies were grossly similar between the fresh and stored blood samples. Our study suggests that reliable and accurate biodosimetry results can be obtained for triage using blood samples stored for up to a week at ambient temperature in the presence of PHA. 相似文献
52.
N. R. Ehemann X. A. Pérez‐Palafox K. Pabón‐Aldana P. A. Mejía‐Falla A. F. Navia V. H. Cruz‐Escalona 《Journal of fish biology》2017,91(4):1228-1235
This study found that the reef stingray Urobatis concentricus presents a matrotrophic aplacental viviparous reproduction with yolk sac and trophonemata formation. Growth of ovarian follicles occurs asynchronously and continuously with fecundity of three embryos per female. A maximum size of 58·4 cm total length and 37·6 cm disc width was recorded, corresponding to a mature female of 3 or 4 years of age. 相似文献
53.
Karel Vives Iván Andújar José Carlos Lorenzo Oscar Concepción Martha Hernández Maritza Escalona 《Plant Cell, Tissue and Organ Culture》2017,131(1):195-199
Stevia rebaudiana is beneficial to treat diabetes because of its low-calorie glucoside sweeteners. Natural and vegetative propagation are inefficient. In vitro techniques are an attractive alternative but low propagation and reproducibility rates have been reported. Therefore, different ways to increase natural sweetener production in vitro, such as BIT®, are required. We compared semisolid medium, liquid medium and BIT® in terms of Stevia biomass and steviol glycosides production. At 21 days of culture, morphological quality of BIT®-derived shoots was best and coupled with shoot fresh and dry weight that were more than seven times higher in BIT® compared with micropropagation in liquid or semisolid media. In turn, the total content of steviol glycosides produced was also higher in bioreactors. The usefulness of BIT® to produce plant metabolites in vitro is again demonstrated, even if additional experiments are required to increase the economic efficiency of the process. 相似文献
54.
Ninety ejaculates from a total of 76 AI boars were extended in Beltsville Thawing Solution (BTS). Boar identity, breed, weight
of the ejaculate and sperm concentration were registered. Motility and acrosome integrity were assessed after storage at 16–18°C
for 6, 30, 54, 78, and 102 h. Storage time had a significant influence on both motility (p < 0.01) and acrosome integrity
(p < 0.001). The Least Square Means for percentage of motility showed a small decline from 79.8% after 6 h of storage to 78.4%
at 102 h. Motility at 78 and 102 h was significantly different from motility at 6 h (p < 0.05). The percentage of sperm cells
with normal acrosomes declined throughout the experiment. The Least Square Means for 6, 30, 54, 78, and 102 h of storage were
93.9%, 90.6%, 88.0%, 84.8%, and 78.2%, respectively. The decrease in acrosome integrity from one storage time to the next
was highly significant throughout the trial (p < 0.001). There was a significant influence of boar (p < 0.001) and sperm concentration
(p < 0.01) on motility, while acrosome integrity was affected only by boar (p < 0.001). Breed of the boars and weight of the
ejaculate did not influence the dependent variables. 相似文献
55.
Raul Araya-Secchi Tomas Perez-Acle Seung-gu Kang Tien Huynh Alejandro Bernardin Yerko Escalona Jose-Antonio Garate Agustin D. Martínez Isaac E. García Juan C. Sáez Ruhong Zhou 《Biophysical journal》2014
Connexins (Cxs) are a family of vertebrate proteins constituents of gap junction channels (GJCs) that connect the cytoplasm of adjacent cells by the end-to-end docking of two Cx hemichannels. The intercellular transfer through GJCs occurs by passive diffusion allowing the exchange of water, ions, and small molecules. Despite the broad interest to understand, at the molecular level, the functional state of Cx-based channels, there are still many unanswered questions regarding structure-function relationships, perm-selectivity, and gating mechanisms. In particular, the ordering, structure, and dynamics of water inside Cx GJCs and hemichannels remains largely unexplored. In this work, we describe the identification and characterization of a believed novel water pocket—termed the IC pocket—located in-between the four transmembrane helices of each human Cx26 (hCx26) monomer at the intracellular (IC) side. Using molecular dynamics (MD) simulations to characterize hCx26 internal water structure and dynamics, six IC pockets were identified per hemichannel. A detailed characterization of the dynamics and ordering of water including conformational variability of residues forming the IC pockets, together with multiple sequence alignments, allowed us to propose a functional role for this cavity. An in vitro assessment of tracer uptake suggests that the IC pocket residue Arg-143 plays an essential role on the modulation of the hCx26 hemichannel permeability. 相似文献
56.
57.
Carlos Eduardo Aragón Maritza Escalona Roberto Rodriguez Maria Jesús Cañal Iris Capote Danilo Pina Justo González-Olmedo 《In vitro cellular & developmental biology. Plant》2010,46(1):89-94
In vitro physiology and carbon metabolism can be affected by the sink–source relationship. The effect of different sucrose concentrations
(10, 30, and 50 g L−1), light intensities (80 and 150 μmol m−2 s−1), and CO2 levels (375 and 1,200 μmol mol−1) were tested during plantain micropropagation in temporary immersion bioreactors. Activities of pyruvate kinase, phosphoenol
pyruvate carboxylase, and the photosynthesis rate were recorded. From the morphological and practical point of view, the best
results were obtained when plants were cultured with 30 g L−1 sucrose, 80 μmol m−2 s−1 light intensity, and 1,200 μmol mol−1 CO2 concentration. This treatment improved leaf and root development, reduced respiration during in vitro culture, and increased starch level at the end of the hardening phase. In addition to that, the number of competent plants
was increased from 80.0% to 91.0% at the end of the in vitro phase and the survival percentage from 95.71% to 99.80% during ex vitro hardening. 相似文献
58.
S. Roels C. Noceda M. Escalona J. Sandoval M.J. Canal R. Rodriguez P. Debergh 《Plant Cell, Tissue and Organ Culture》2006,84(2):100138-100146
The positive effect of ventilation of the culture container on in vitro shoot proliferation and quality was already proven for different species. Hereafter we report on the evolution of the headspace
during in vitro culture of plantain in a Temporary Immersion Bioreactor (TIB) on the one hand, and culture on semi-solid medium on the other
hand. The CO2 and C2H4 concentration reached a maximum of 12% and 0.45 μl l−1, respectively in the control treatment on semi-solid medium, compared to 5.7% CO2 and 0.06 μl l−1 C2H4 in TIB. The minimal O2-concentration on semi-solid medium was 15.1%, compared to 19.3% in TIB. The multiplication rate was best in TIB, 6.4 compared
to 4.3 in semi-solid conditions, and this was also the case for shoot height (4.3 cm compared to 3.3 cm), and leaf number
(2.6 compared to 1.6). Moreover shoots produced on semi-solid medium showed distorted leaves. A typical day-night pattern
in CO2 and O2 concentration was observed in TIB, as well as on semi-solid medium; this is illustrative for the photosynthetic capacity
of the plant material produced in both systems. 相似文献
59.
de los Blanco María A. Nieves Nadina Sánchez Margelys Borroto Carlos G. Castillo Ramiro González Justo L. Escalona Maritza Báez Evelio Hernández Zulema 《Plant Cell, Tissue and Organ Culture》1997,51(3):153-158
Plant regeneration from cultured immature inflorescence segments (3–5 mm) of sugarcane (Saccharum sp) var. CP 5243 was obtained
via somatic embryogenesis. Embryogenic callus culture was initiated on MS medium supplemented with 2,4-D (13.5 μM) over 30
days. The callus was subcultured every 15–20 days on MS medium supplemented with 2,4-D (4.5 μM), arginine (50 mg l-1) and proline (500 mg l-1). The callus was subjected to five treatments: 2,4-D (4.5 μM), Picloram (8.2 μM) and Dicamba (22.6 μM). SPC was determined
at the beginning, after 20 days in culture, and every 24 hours thereafter up to 72 hours. SDS-PAGE electrophoresis was performed
based on soluble protein content. Some differences were found between SPC and bands (intensity and number) for all treatments
associated with shoot formation. The results point out the association of soluble protein content and callus regenerative
ability of sugarcane cv. CP5243 and suggest the presence of a marker protein (between 55–70 kDa) for embryogenic callus regeneration
ability in this cultivar.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
60.
Lorenzo José Carlos González Boris Luis Escalona Maritza Teisson Claude Borroto Carlos 《Plant Cell, Tissue and Organ Culture》1998,54(3):197-200
A new protocol was established for sugarcane cv. C-1051-73 shoot formation in a temporary immersion system. The two-step protocol
involves shoot formation in 50 ml of culture medium per explant and 1.0 mg l-1 paclobutrazol for 30 days followed by shoot
elongation by exposure to 1.0 mg l-1 gibberellic acid for 15 days. The multiplication rate was doubled in comparison with
the conventional micropropagation protocol (Jiménez et al., 1995) and the cost has been reduced by 46%. Three additional sugarcane
varieties have been micropropagated according to this new protocol and results are comparable. Temporary immersion-derived
plants have also been compared with conventionally propagated plants in sugarcane fields for more than 9 months and their
agricultural indicators of performance are similar.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献