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41.
Roberto de la Herrán Miguel Hermida Juan Andres Rubiolo Jèssica Gómez-Garrido Fernando Cruz Francisca Robles Rafael Navajas-Pérez Andres Blanco Paula Rodriguez Villamayor Dorinda Torres Pablo Sánchez-Quinteiro Daniel Ramirez Maria Esther Rodríguez Alberto Arias-Pérez Ismael Cross Neil Duncan Teresa Martínez-Peña Ana Riaza Adrian Millán M. Cristina De Rosa Davide Pirolli Marta Gut Carmen Bouza Diego Robledo Laureana Rebordinos Tyler Alioto Carmelo Ruíz-Rejón Paulino Martínez 《Molecular ecology resources》2023,23(4):886-904
Sex determination (SD) shows huge variation among fish and a high evolutionary rate, as illustrated by the Pleuronectiformes (flatfishes). This order is characterized by its adaptation to demersal life, compact genomes and diversity of SD mechanisms. Here, we assembled the Solea senegalensis genome, a flatfish of great commercial value, into 82 contigs (614 Mb) combining long- and short-read sequencing, which were next scaffolded using a highly dense genetic map (28,838 markers, 21 linkage groups), representing 98.9% of the assembly. Further, we established the correspondence between the assembly and the 21 chromosomes by using BAC-FISH. Whole genome resequencing of six males and six females enabled the identification of 41 single nucleotide polymorphism variants in the follicle stimulating hormone receptor (fshr) consistent with an XX/XY SD system. The observed sex association was validated in a broader independent sample, providing a novel molecular sexing tool. The fshr gene displayed differential expression between male and female gonads from 86 days post-fertilization, when the gonad is still an undifferentiated primordium, concomitant with the activation of amh and cyp19a1a, testis and ovary marker genes, respectively, in males and females. The Y-linked fshr allele, which included 24 nonsynonymous variants and showed a highly divergent 3D protein structure, was overexpressed in males compared to the X-linked allele at all stages of gonadal differentiation. We hypothesize a mechanism hampering the action of the follicle stimulating hormone driving the undifferentiated gonad toward testis. 相似文献
42.
Alicia Mathis Kevin L. Murray & Caleb R. Hickman 《Ethology : formerly Zeitschrift fur Tierpsychologie》2003,109(2):159-170
Prey may experience ontogenetic changes in vulnerability to some predators, either because of changes in morphology or experience. If prey match their level of antipredator behavior to the level of predatory threat, prey responses to predators should reflect the appropriate level of threat for their stage of development. For larval salamanders, responses to predators may change with body size because larger larvae are less vulnerable to predation by gape‐limited predators or because fleeing responses by large salamanders may be more effective than for smaller salamanders. In a field experiment, small larval ringed salamanders, Ambystoma annulatum, responded to chemical stimuli (‘kairomones’) from predatory newts, Notophthalmus viridescens, with an antipredator response (decreased activity). Laboratory‐reared larvae decreased their activity following exposure to newt kairomones, indicating that larval ringed salamanders do not require experience with newts to recognize them as predators. In both experiments, larvae distinguished between chemical stimuli from newts and stimuli from tadpoles (non‐predators) and a blank control. In a third experiment, field‐caught (experienced) larvae showed a graded response to newt kairomones based on their body size: small larvae tended to decrease their activity while larger larvae showed no change or an increase in activity. This graded response was not observed for neutral stimuli, indicating that it is predator‐specific. Therefore, ringed salamander larvae exhibit threat‐sensitive ontogenetic changes in their response to chemical stimuli from predatory newts. 相似文献
43.
Changes in maximum oxygen uptake during prolonged training, overtraining, and detraining in horses 总被引:2,自引:0,他引:2
Tyler Catherine M.; Golland Lorraine C.; Evans David L.; Hodgson David R.; Rose Reuben J. 《Journal of applied physiology》1996,81(5):2244-2249
Tyler, Catherine M., Lorraine C. Golland, David L. Evans,David R. Hodgson, and Reuben J. Rose. Changes in maximum oxygenuptake during prolonged training, overtraining, and detraining inhorses. J. Appl. Physiol. 81(5):2244-2249, 1996.Thirteen standardbred horses were trained asfollows: phase 1 (endurance training, 7 wk),phase 2 (high-intensity training, 9 wk),phase 3 (overload training, 18 wk), andphase 4 (detraining, 12 wk). Inphase 3, the horses were divided intotwo groups: overload training (OLT) and control (C). The OLT groupexercised at greater intensities, frequencies, and durations than groupC. Overtraining occurred after 31 wk of training and was defined as asignificant decrease in treadmill run time in response to astandardized exercise test. In the OLT group, there was a significantdecrease in body weight (P < 0.05).From pretraining values of 117 ± 2 (SE)ml · kg1 · min1,maximal O2 uptake(O2 max) increased by15% at the end of phase 1, and when signs of overtraining werefirst seen in the OLT group,O2 max was 29%higher (151 ± 2 ml · kg1 · min1in both C and OLT groups) than pretraining values. There was nosignificant reduction inO2 max until after 6 wk detraining whenO2 max was 137 ± 2 ml · kg1 · min1.By 12 wk detraining, meanO2 max was134 ± 2 ml · kg1 · min1,still 15% above pretraining values. When overtraining developed, O2 max was notdifferent between C and OLT groups, but maximal values forCO2 production (147 vs. 159 ml · kg1 · min1)and respiratory exchange ratio (1.04 vs. 1.11) were lower in the OLTgroup. Overtraining was not associated with a decrease inO2 max and, afterprolonged training, decreases inO2 max occurredslowly during detraining. 相似文献
44.
Bioreactors for surface-immobilized cells 总被引:2,自引:0,他引:2
P. T. Tyler W. G. W. Kurz N. L. Paiva S. Chavadej 《Plant Cell, Tissue and Organ Culture》1995,42(1):81-90
Surface immobilization of plant cells avoids the problem of hydrodynamic or shear stress, which tends to be characteristic of suspended cells cultured in typical, mechanically agitated bioreactor systems. Surface immobilization also promotes the natural tendency for plant cells to aggregate, which may improve the synthesis and accumulation of secondary metabolites. In addition, exchange of medium is made simple in surface-immobilized systems, and extracellular secondary products are easily recovered on a continuous basis. However, problems related to regulation of the thickness of the immobilized cell layer, maintenance of the biomass in a productive condition, and vacuolar retention of secondary products have yet to be resolved satisfactorily. This review focusses on two surface-immobilization technologies, differing primarily in the nature and the configuration of the inert support. Prototypes of these designs have been applied to a variety of plant cell systems at bioreactor volumes up to 20 litres. Results obtained with several alternative technologies are also summarized.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- SIPCB
surface-immobilized plant cell bioreactor
National Research Council of Canada publication no. 38460 相似文献
45.
Observations on temporary waters in northwestern Australia 总被引:3,自引:1,他引:2
46.
Reovirus infection and tissue injury in the mouse central nervous system are associated with apoptosis. 总被引:14,自引:9,他引:5 下载免费PDF全文
Reovirus serotype 3 strains infect neurons within specific regions of the neonatal mouse brain and produce a lethal meningoencephalitis. Viral replication and pathology colocalize and have a predilection for the cortex, hippocampus, and thalamus. We have shown previously that infection of cultured fibroblasts and epithelial cells with reovirus type 3 Dearing (T3D) and other type 3 reovirus strains results in apoptotic cell death, suggesting that apoptosis is a mechanism of cell death in vivo. We now report that T3D induces apoptosis in infected mouse brain tissue. To determine whether reovirus induces apoptosis in neural tissues, newborn mice were inoculated intracerebrally with T3D, and at various times after inoculation, brain tissue was assayed for viral antigen by immunostaining and apoptosis was identified by DNA oligonucleosomal laddering and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Cells were also stained with cresyl violet to detect morphological changes characteristic of apoptosis, including chromatin condensation and cell shrinkage. DNA laddering was detected in T3D- but not in mock-infected brain tissue. Apoptotic cells were restricted to the same regions of the brain in which infected cells and tissue damage were observed. These findings suggest that virus-induced apoptosis is a mechanism of cell death, tissue injury, and mortality in reovirus-infected mice. The correlation between apoptosis and pathogenesis in vivo identifies apoptosis as a potential target for molecular and pharmacological strategies designed to curtail or prevent diseases resulting from induction of this cell death pathway. 相似文献
47.
Reovirus-induced apoptosis of MDCK cells is not linked to viral yield and is blocked by Bcl-2. 总被引:10,自引:10,他引:0 下载免费PDF全文
S E Rodgers E S Barton S M Oberhaus B Pike C A Gibson K L Tyler T S Dermody 《Journal of virology》1997,71(3):2540-2546
In this study, we investigated the relationship between reovirus-induced apoptosis and viral growth. Madin-Darby canine kidney (MDCK) epithelial cells infected with prototype reovirus strains type 1 Lang (T1L) or type 3 Dearing (T3D) were found to undergo apoptosis, and T3D induced apoptosis of MDCK cells to a substantially greater extent than T1L. By using T1L x T3D reassortant viruses, we found that differences in the capacities of these strains to induce apoptosis are determined by the viral S1 and M2 gene segments. These genes encode viral outer-capsid proteins that play important roles in viral entry into cells. T1L grew significantly better in MDCK cells than T3D, and these differences in growth segregated with the viral L1 and M1 gene segments. The L1 and M1 genes encode viral core proteins involved in viral RNA synthesis. Bcl-2 overexpression in MDCK cells inhibited reovirus-induced apoptosis but did not substantially affect reovirus growth. These findings indicate that differences in the capacities of reovirus strains to induce apoptosis and grow in MDCK cells are determined by different viral genes and that premature cell death by apoptosis does not limit reovirus growth in MDCK cells. 相似文献
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