scholarly journals 172 Calorimetric Evaluation of Apple Seed Dormancy

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 420A-420
Author(s):  
E. Carvajel-Millan ◽  
A.A. Gardea ◽  
V. Guerrero-P ◽  
F. Goycoolea ◽  
C. Rivera

Apple embryos from moist seeds kept at 4 °C were used for a calorimetric characterization of Red and Golden Delicious apple seed dormancy. Seeds were sampled at 100-h intervals during 1200 h. The metabolic response of such samples was compared to that from chilled Golden Delicious seeds (>1200 h) stored under controlled atmosphere (CA). Isothermal calorimetry at 25 °C, evaluated metabolic activity (q), respiration rate (RCO2), metabolic 65 °C estimated activation energy (Ea) in a 10 to 20 °C range, and respiration coefficients (Q10) from 10 to 50 °C at 10 °C intervals. Data showed a direct relationship between chilling exposure and embryo metabolic responses from both cultivars. Once chilling requirement was satisfied, Red and Golden Delicious seeds presented a significant increase (P ≤ 0.05) in q, 0.94 and 0.98 μW/mg dry weight (dw); RCO2, 9.9 and 7.6 mmol CO2/mg dw; and RSG·ΔHB, 3.6 and 2.5 μW/mg dw, respectively. On the other hand, q/RCO2 did not follow a definite pattern, neither in Red nor Golden Delicious cultivars. Ea decreased 19.2 and 23.4 J/mol per °K per mg dw in Red and Golden Delicious, respectively, as a function of seed chilling. Q10 showed a significant response to temperature, but not to chilling exposure. Golden Delcious seeds from CA showed a significant reduction on q, RCO2, and RSG·ΔHB of 0.28 μW/mg dw, 2.47 mmol CO2/mg dw, and 14 μW/mg dw, respectively. Results show that calorimetry is a sufficiently sensitive, fast, and precise tool to quantify metabolic responses during seed chilling, as evolving energy.

2010 ◽  
Vol 39 (12) ◽  
pp. 2560-2568 ◽  
Author(s):  
Altevir Signor ◽  
Luiz Edivaldo Pezzato ◽  
Pedro de Magalhães Padilha ◽  
Carlos Roberto Padovani ◽  
Margarida Maria Barros

This research evaluated the influence of yeast and zinc on growth performance and metabolic responses of Nile tilapia. Diets were formulated to contain 32.0% digestible protein and 3,240 kcal DE/kg diet and the following autolized yeast (%):zinc (mg/kg)relationships: 0.0:0.0; 0.0:79.5; 2.0:0.0; 0.795:79.5; 2.0:200; 4.0:400; 6.0:600; 12.0:1,200 and 14.0:1,400. It was used 135 fingerlings (7.27 ± 0.19 g), distributed in a complete random design in 27 50-L aquaria and they were fed ad libitum four times a day for 128 days. It was evaluated growth performance and metabolic responses, weight gain, apparent feed conversion; protein efficiency and survival rate; percentage of protein, ether extract, dry weight and ashes in the muscle and in the bones; ammonia concentration and kinetic activity of alkaline phosphatase in the liver; ammonia, kinetic activity of alkaline phosphatase, urea and lipids in the plasma and; minerals in plasma, in the liver and in the bones of the fish. High levels of yeast and zinc in the diet impaired growth performance and metabolic responses of the fish. Autolized yeast at the level of 2.0% determines the best growth performance. Levels higher than 6.0% of autolized yeast and 600 mg zinc in the diets impair growth performance and lipid metabolism in fish and levels higher than 4.0% of autolized yeast and 400 mg zinc/kg in the diet impair mineral metabolism.


2020 ◽  
Author(s):  
Naseh Pahlavani ◽  
Safieh Firouzi ◽  
Reza Rezvani ◽  
Lida Jarahi ◽  
Mahsa Malekahmadi ◽  
...  

BACKGROUND Background: Prior studies have shown that meal composition is capable of effect on metabolic response and arterial stiffness indexes. OBJECTIVE Objective: A three-phase parallel study will design to investigate the effects of meal composition on metabolic parameters and arterial stiffness indexes among lean and obese adult. The planned study protocol is presented METHODS Methods/design: This is a parallel clinical trial targeting adults (aged 18–35 years, free from any diseases) selected by inclusion and exclusion criteria at Mashhad University Medical Sciences. Each subject will complete three interventions with a washout period of one week: high carbohydrate, high protein and high fat meal. The postprandial effect will be assessed during 360 minutes from each meal including energy expenditure component, pulse wave analysis and pulse wave velocity and blood sampling. RESULTS N/A CONCLUSIONS Metabolic Responses, Macronutrients Composition, Arterial Stiffness, Study Protocol: The differences in postprandial response due to different meal composition could affect of metabolic and vascular parameters. This could provide necessary information for the establishment of new strategies in terms of nutritional education and metabolic and vascular improvement. CLINICALTRIAL Trial registration: Iranian Registry of Clinical Trials: IRCT20190818044552N1. Registered on August 26, 2019


Author(s):  
David M Hudson

Abstract Freshwater crustaceans are distributed throughout the montane and lowland areas of Colombia, and are therefore a useful indicator group for how aquatic species will respond to climate change. As such, metabolic determination of physiological performance was evaluated for the Colombian pseudothelphusid crab, Neostrengeria macropa (H. Milne Edwards, 1853), over a temperature range inclusive of current temperatures and those predicted by future scenarios in the plateau around the city of Bogotá, namely from 8 °C to 30 °C. The performance results mostly aligned with previous exploratory behavioral determination of the ideal temperature range in the same species, although the metabolism increased at the highest temperature treatments, a point when exploratory behavior declined. These results indicate that this species of montane crab behaviorally compensates for increased thermal stress by decreasing its physical activity, which could have negative predator-prey consequences with changes to community structure as different species undergo climate-mediated geographic range shifts in the region. As this species is endemic to the plateau surrounding Bogotá, it also experiences a number of other stressors to its survival, including infrastructure development and invasive species.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.


2004 ◽  
Vol 32 ◽  
pp. 1-9
Author(s):  
B Essén–Gustavsson

AbstractMuscle is a tissue with a great plasticity due to the fact that it is composed of fibres having different contractile and metabolic properties. In horses, muscle metabolic responses to exercise are studied by taking biopsies from the gluteus medius muscle. Histochemical stains are used to identify slow contracting type I fibres and fast contracting type IIA and type IIB fibres and to evaluate fibre areas, capillary supply, oxidative capacity, glycogen and lipid content in a muscle. Biochemical analyses of substrates, metabolites and enzyme activities are performed either on a whole piece of muscle, on pools of fibres or on single fibres of identified type.All fibres contain glycogen whereas lipid is mainly found in type I and type IIA fibres that have smaller cross–sectional areas and a higher oxidative capacity than type IIB fibres. Large variations can be seen in metabolic profile between and within fibre types. The most common muscular adaptation to training is an increase in oxidative capacity, capillary density and an increase in the type IIA/IIB ratio. The order of recruitment of fibres during most types of exercise is from type I to type IIA and type IIB.The higher the intensity of exercise, the faster is the breakdown of glycogen. After racing (1640-2640m), and after high intense treadmill exercise, concentrations of lactate and inosine monophosphate (IMP) are increased in the muscle and concentrations of glycogen, adenosine triphosphate (ATP) and creatine phosphate (CP) decreased. Extremely low ATP and high IMP concentrations especially in some type II fibres are observed after racing.After exercise of low intensity and long duration glycogen and triglyceride stores in muscle are utilised, amino acid metabolism is enhanced and protein degradation may occur. After submaximal treadmill exercise to fatigue and after endurance rides glycogen is degraded and depletion occurs mainly in type I and type IIA fibres.Fibre type composition, substrate sources and differences in metabolic properties among fibres and the extent to which fibres are recruited are all factors that influence the metabolic responses of muscle to exercise. Biochemical analyses on whole muscle must be interpreted with caution since large variations in metabolic response to exercise occur among different fibres.


Science ◽  
2018 ◽  
Vol 360 (6392) ◽  
pp. 1014-1017 ◽  
Author(s):  
Min Chen ◽  
Steven Penfield

Plants integrate seasonal signals, including temperature and day length, to optimize the timing of developmental transitions. Seasonal sensing requires the activity of two proteins, FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT), that control certain developmental transitions in plants. During reproductive development, the mother plant uses FLC and FT to modulate progeny seed dormancy in response to temperature. We found that for regulation of seed dormancy, FLC and FT function in opposite configuration to how those same genes control time to flowering. For seed dormancy, FT regulates seed dormancy through FLC gene expression and regulates chromatin state by activating antisense FLC transcription. Thus, in Arabidopsis the same genes controlled in opposite format regulate flowering time and seed dormancy in response to the temperature changes that characterize seasons.


1990 ◽  
Vol 4 (1) ◽  
pp. 41 ◽  
Author(s):  
C. A. Lanciani ◽  
J. T. Giesel ◽  
J. F. Anderson ◽  
S. S. Emerson

2016 ◽  
Vol 115 (3) ◽  
pp. 1157-1169 ◽  
Author(s):  
Sandrine Saillet ◽  
Pascale P. Quilichini ◽  
Antoine Ghestem ◽  
Bernard Giusiano ◽  
Anton I. Ivanov ◽  
...  

Interpretation of hemodynamic responses in epilepsy is hampered by an incomplete understanding of the underlying neurovascular coupling, especially the contributions of excitation and inhibition. We made simultaneous multimodal recordings of local field potentials (LFPs), firing of individual neurons, blood flow, and oxygen level in the somatosensory cortex of anesthetized rats. Epileptiform discharges induced by bicuculline injections were used to trigger large local events. LFP and blood flow were robustly coupled, as were LFP and tissue oxygen. In a parametric linear model, LFP and the baseline activities of cerebral blood flow and tissue partial oxygen tension contributed significantly to blood flow and oxygen responses. In an analysis of recordings from 402 neurons, blood flow/tissue oxygen correlated with the discharge of putative interneurons but not of principal cells. Our results show that interneuron activity is important in the vascular and metabolic responses during epileptiform discharges.


2018 ◽  
Vol 28 (2) ◽  
pp. 112-122 ◽  
Author(s):  
Daniel Chamorro ◽  
Belén Luna ◽  
José M. Moreno

AbstractIn seasonal climates, germination timing is mainly controlled by temperature, especially in species with physiological seed dormancy. The germination response to temperature may, however, vary among populations across the distribution range of species. Understanding how populations along climate gradients vary in their sensitivity to temperature is important for determining their vulnerability to climate variability and change. Here, we investigated the germination response of two Erica species with physiological seed dormancy (E. australis and E. umbellata) to changes in temperature throughout the seasons (simulated autumn through to spring) and to the local climate in six localities across a latitudinal gradient in western Iberia. Effects were studied with and without exposing the seeds to a heat shock. The local climate of seed provenance emerged as a key factor in modifying the germination sensitivity to germination temperature and their variation through the seasons. Although each species showed idiosyncratic germination responses to temperature treatments and across the gradient, germination of both species was sensitive to warmer temperatures and to a heat shock. Both showed similar seasonal germination patterns: as we moved from south to north, populations tended to have a larger germination peak in spring, which was greater at colder temperatures. We conclude that rising temperatures associated with climate change will affect these species, particularly at their northern ranges, where many seeds will remain dormant during warmer winters. Arguably, models aiming at assessing climate change impacts in these species need to include such variability across latitude.


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