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1.
Mang C. Yu Amos G. Gona Ophelia Gona Suad Al-Rabiai Stanley Von Hagen Edwin Cohen 《Bioelectromagnetics》1993,14(5):449-458
This study was undertaken to determine the effects of extremely low frequency (ELF; 60 Hz) electromagnetic (EM) fields on somatic growth and cortical development, as well as biochemical and morphological maturation, of the rat neopallium. On the fifth day of pregnancy, female rats were put in pairs into plastic cages that were housed in a specially constructed apparatus for irradiation under three separate sets of combination and intensity: 1) 1 kV/m and 10 gauss; 2) 100 kV/m and 1 gauss; and 3) 100 kV/m and 10 gauss. The dams were exposed for 23 h daily, from days 5 through 19 postconception after which they were returned to cages outside the exposure apparatus until they littered. The neonates were culled to eight pups per litter. At 0 (birth), 5, 12, and 19 days postnatally, they were killed for biochemical and morphological studies. Another group of pregnant rats was sham-exposed in an identical apparatus, which was not energized, and the pups were used as controls. The irradiated rats exhibited no physical abnormalities, nor did they show brain deformities such as swelling or herniation following exposure to ELF-EM fields. There was no difference in somatic growth between control and exposed rats, but a small reduction in cortical weight was observed in rats exposed at 1 kV/m and 10 gauss, and 100 kV/m and 1 gauss, respectively. Biochemical measurements of DNA. RNA, protein, and cerebroside concentrations indicated that among the three separate exposures, only the neopallium of rats exposed at 1 kV/m and 10 gauss showed a small reduction in DNA level, as well as small reductions in RNA and protein levels. No changes were noticed in cerebroside levels in any exposed animals, and there were no differences in protein/DNA and cerebroside/DNA ratios between control and exposed rats. Morphological observations did not reveal any detectable alterations in the irradiated rats. These results indicate that exposure to ELF-EM fields caused minimal or no changes in somatic growth and cerebral development of the rat. © 1993 Wiley-Liss, Inc. 相似文献
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Ophelia Gona 《The Histochemical journal》1979,11(6):709-718
Synopsis To examine the hypothesis that the histochemical characteristics of teleostean mucus reflect functional characteristics, mucous cells were studied in four related and behaviourally similar species of fish (Family Belontidae). Histochemical characteristics were determined with Alcian Blue at both pH 2.6 and pH 1.0 followed by the periodic acid-Schiff technique. It was found that the four species differed in glycoprotein type as well as in number of mucus-containing cells. The differences are ciscussed in regard to functional characteristics and environmental influence. 相似文献
4.
Paul S Marley Aboubacar Toure Jay Shebayan DA Aba AO Toure AG Diallo 《Archives Of Phytopathology And Plant Protection》2013,46(1):29-34
Fourteen elite sorghum lines were evaluated for their resistance to Striga hermonthica at three locations in Nigeria and Mali. Results showed that many of the lines especially MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64 (Keninkédié) and the check SRN 39 remained resistant to Striga in all locations with low emerged Striga counts, while SAMSORG 14 had the highest Striga infestation in all locations. Considerable variation in reaction to Striga infestation was observed on Séguètana, 97-SB-F5DT-63 (Wasa), 97-SB-F5DT-65, CMDT 38, CMDT 39 and CMDT 45 which were susceptible to Striga at Samaru, Nigeria but were resistant to Striga at both locations in Mali. Based on low Striga resistance and high grain yield, lines MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64, 97-SB-F5DT-65, CMDT 39 and SAMSORT 14 have been nominated for wider evaluation across more West African countries. 相似文献
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Carmen Martínez José A Molina Hortensia Alonso-Navarro Félix J Jiménez-Jiménez José AG Agúndez Elena García-Martín 《BMC neurology》2010,10(1):71
Background
Human serum paraoxonase 1 (PON1) plays a major role in the metabolism of several organophosphorus compounds. The enzyme is encoded by the polymorphic gene PON1, located on chromosome 7q21.3. Aiming to identify genetic variations related to the risk of developing brain tumors, we investigated the putative association between common nonsynonymous PON1 polymorphisms and the risk of developing astrocytoma and meningioma. 相似文献6.
JI Priego AG Lucas-Cuevas I Aparicio JV Giménez JM Cortell-Tormo P Pérez-Soriano 《Biology of sport / Institute of Sport》2015,32(3):219-223
The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) – a 5-min maximal effort run in order to determine the participants’ maximal aerobic speed; and tests 2) and 3) – a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLACEBO stockings at random. Cardiorespiratory parameters (minute ventilation, heart rate, relative oxygen consumption, relative carbon dioxide production, ventilatory equivalents for oxygen and carbon dioxide, and oxygen pulse) were measured. Before each test in the laboratory, the participants trained with the randomly assigned stockings (GCS or PLACEBO) for three weeks. No significant differences between GCS and PLACEBO were found in any of the cardiorespiratory parameters. In conclusion, the present study provides evidence that running with GCS for three weeks does not influence cardiorespiratory parameters in recreational runners. 相似文献
7.
Thomas GH; Newbern EC; Korte CC; Bales MA; Muse SV; Clark AG; Kiehart DP 《Molecular biology and evolution》1997,14(12):1285-1295
Many structural, signaling, and adhesion molecules contain tandemly
repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin
superfamily of F-actin-crosslinking proteins contains an array of triple
alpha-helical motifs (spectrin repeats). We present here the complete
sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H).
The sequence of beta H supports the origin of alpha- and beta-spectrins
from a common ancestor, and we present a novel model for the origin of the
spectrins from a homodimeric actin-crosslinking precursor. The pattern of
similarity between the spectrin repeat units indicates that they have
evolved by a series of nested, nonuniform duplications. Furthermore, the
spectrins and dystrophins clearly have common ancestry, yet the repeat unit
is of a different length in each family. Together, these observations
suggest a dynamic period of increase in repeat number accompanied by
homogenization within each array by concerted evolution. However, today,
there is greater similarity of homologous repeats between species than
there is across repeats within species, suggesting that concerted evolution
ceased some time before the arthropod/vertebrate split. We propose a
two-phase model for the evolution of the spectrin repeat arrays in which an
initial phase of concerted evolution is subsequently retarded as each new
protein becomes constrained to a specific length and the repeats diverge at
the DNA level. This evolutionary model has general applicability to the
origins of the many other proteins that have tandemly repeated motifs.
相似文献
8.
Higher‐order assemblies of oligomeric cargo receptor complexes form the membrane scaffold of the Cvt vesicle
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Arjen J Jakobi Abul K Tarafder Yury S Bykov Andrea Picco Wanda Kukulski Jan Kosinski Wim JH Hagen Arvind C Ravichandran Matthias Wilmanns Marko Kaksonen John AG Briggs Carsten Sachse 《EMBO reports》2016,17(7):1044-1060
Selective autophagy is the mechanism by which large cargos are specifically sequestered for degradation. The structural details of cargo and receptor assembly giving rise to autophagic vesicles remain to be elucidated. We utilize the yeast cytoplasm‐to‐vacuole targeting (Cvt) pathway, a prototype of selective autophagy, together with a multi‐scale analysis approach to study the molecular structure of Cvt vesicles. We report the oligomeric nature of the major Cvt cargo Ape1 with a combined 2.8 Å X‐ray and negative stain EM structure, as well as the secondary cargo Ams1 with a 6.3 Å cryo‐EM structure. We show that the major dodecameric cargo prApe1 exhibits a tendency to form higher‐order chain structures that are broken upon interaction with the receptor Atg19 in vitro. The stoichiometry of these cargo–receptor complexes is key to maintaining the size of the Cvt aggregate in vivo. Using correlative light and electron microscopy, we further visualize key stages of Cvt vesicle biogenesis. Our findings suggest that Atg19 interaction limits Ape1 aggregate size while serving as a vehicle for vacuolar delivery of tetrameric Ams1. 相似文献
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In the course of a freeze-cleave study on intercellular junctions in the regenerating rat liver, we observed an unusual array of intramembranous particles located in regions of contact between endothelial cells lining the hepatic sinusoids. These arrays were characterized by an accumulation of particles which resembled a zonula occludens in their linear deployment but differed in that the contact regions were composed of individual particles which remained separated from each other by regular particle-free intervals. 相似文献
10.
Gona AG 《Tissue & cell》1971,3(4):557-566
Radioautographic studies revealed that prolactin markedly stimulates the incorporation of H(3)-proline into the basement lamella of the tail fin of frog tadpole. Radioactivity in fibroblasts reached a peak at 3 hours. Thereafter, the number of silver grains in fibroblasts was reduced with concomitant increase in the basement lamella. Fibroblasts of the prolactin animals also showed extensively developed rough endoplasmic reticulum and Golgi elements. Epidermis of control animals was labelled as in the prolactin animals, although the basement lamella was sparsely labelled. Fibroblasts, not the epidermis, seem to secrete collagen into the basement lamella. 相似文献