scholarly journals Cone-like rhodopsin expressed in the all-cone retina of the colubrid pine snake as a potential adaptation to diurnality

2017 ◽  
Vol 220 (13) ◽  
pp. 2418-2425 ◽  
Author(s):  
Nihar Bhattacharyya ◽  
Benedict Darren ◽  
Ryan K. Schott ◽  
Vincent Tropepe ◽  
Belinda S. W. Chang
Keyword(s):  
Potential Adaptation ◽  
Pine Snake

scholarly journals Cone-like rhodopsin expressed in the all cone retina of the colubrid pine snake as a potential adaptation to diurnality

2017 ◽  
Author(s):  
Nihar Bhattacharyya ◽  
Benedict Darren ◽  
Ryan K. Schott ◽  
Vincent Tropepe ◽  
Belinda S.W. Chang
Keyword(s):  
Cell Types ◽  
Rhodopsin Gene ◽  
Cone Opsin ◽  
Retinal Photoreceptor ◽  
Pituophis Melanoleucus ◽  
Summary Statement ◽  
Potential Adaptation ◽  
Pine Snake ◽  
Cone Opsins

AbstractColubridae is the largest and most diverse family of snakes, with visual systems that reflect this diversity, encompassing a variety of retinal photoreceptor organizations. The transmutation theory proposed by Walls postulates that photoreceptors could evolutionarily transition between cell types in squamates, but few studies have tested this theory. Recently, evidence for transmutation and rod-like machinery in an all cone retina has been identified in a diurnal garter snake (Thamnophis), and it appears that the rhodopsin gene at least may be widespread among colubrid snakes. However, functional evidence supporting transmutation beyond the existence of the rhodopsin gene remains rare. We examined the all cone retina of another diurnal colubrid,Pituophis melanoleucus, distantly related toThamnophis. We found thatP. melanoleucusexpresses two cone opsins (SWS1, LWS) and rhodopsin (RH1) within the eye. Immunohistochemistry localized rhodopsin to the outer segment of photoreceptors in the all-cone retina of the snake and all opsin genes produced functional visual pigments when expressedin vitro. Consistent with other studies, we found thatP. melanoleucusrhodopsin is extremely blue-shifted. Surprisingly,P. melanoleucusrhodopsin reacted with hydroxylamine, a typical cone opsin characteristic. These results support the idea that the rhodopsin-containing photoreceptors ofP. melanoleucusare the products of evolutionary transmutation from rod ancestors, and suggests that this phenomenon may be widespread in colubrid snakes. We hypothesize that transmutation may be an adaptation for diurnal, brighter-light vision, which could result in increased spectral sensitivity and chromatic discrimination with the potential for colour vision.Summary StatementThe all cone retina of the colubrid snake,Pituophis melanoleucuscontains a blue-shifted rhodopsin with cone opsin-like properties, which may have been adaptive in diurnal snakes.

scholarly journals Basket of options: Unpacking the concept

2021 ◽  
pp. 003072702110194
Author(s):  
E Ronner ◽  
J Sumberg ◽  
D Glover ◽  
KKE Descheemaeker ◽  
CJM Almekinders ◽  
...  
Keyword(s):  
Technological Change ◽  
Rural Areas ◽  
Farm Households ◽  
Agricultural Technologies ◽  
Trade Off ◽  
Individual User ◽  
Opportunities For Learning ◽  
Critical Attention ◽  
The Face ◽  
Potential Adaptation

How to stimulate technological change to enhance agricultural productivity and reduce poverty remains an area of vigorous debate. In the face of heterogeneity among farm households and rural areas, one proposition is to offer potential users a ‘basket of options’ – a range of agricultural technologies from which potential users may select the ones that are best suited to their specific circumstances. While the idea of a basket of options is now generally accepted, it has attracted little critical attention. In this paper, we reflect on outstanding questions: the appropriate dimensions of a basket, its contents and how they are identified, and how a basket might be presented. We conceive a basket of options in terms of its depth (number of options related to a problem or opportunity) and breadth (the number of different problems or opportunities addressed). The dimensions of a basket should reflect the framing of the problem or opportunity at hand and the objective in offering the basket. We recognise that increasing the number of options leads to a trade-off by decreasing the fraction of those options that are relevant to an individual user. Farmers might try out, adapt or use one or more of the options in a basket, possibly leading to a process of technological change. We emphasise that the selection (or not) of specific options from the basket, and potential adaptation of the options, provide important opportunities for learning. Baskets of options can therefore be understood as important boundary concepts that invite critical engagement, comparison and discussion. Significant knowledge gaps remain, however, about the best ways to present the basket and to guide potential users to select the options that are most relevant to them.

Detection of genetic diversity in rough fescue (Festuca campestris Rydb) populations of southern Alberta and British Columbia, Canada, using RAPD markers

2008 ◽  
Vol 88 (2) ◽  
pp. 307-312
Author(s):  
Zhao Mengli ◽  
Han Bing ◽  
Walter D Willms
Keyword(s):  
Genetic Diversity ◽  
British Columbia ◽  
Genetic Distance ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Distance ◽  
Genetic Distances ◽  
Gene Frequencies ◽  
Southern Alberta ◽  
Potential Adaptation ◽  
Rough Fescue

Mountain rough fescue (Festuca campestris Rydb.) is a tufted native grass in southern Alberta and British Columbia, Canada, and has attracted interest for use in reclamation. However, its seed is often available from only a few localized sources and may not be adapted for areas removed from the collection site. We conducted a study to determine the genetic variability among rough fescue populations to assess its potential adaptation. Thirty plants were collected from each of six populations and analyzed using Random Amplified Polymorphic DNA (RAPD). One population (Kamloops, BC) was separated by several mountain ranges from the five easterly Alberta populations.The Kamloops population was also separated from the Alberta populations by genetic distance in two clusters. Of the total genetic variation present in the data, 21% was found among populations while the remaining (79%) was found within populations. Nei’s genetic distances among populations were related to their geographical distances. Genetic differences among populations appeared to be caused primarily by differences in gene frequencies rather than rare genes. Also, genetic diversity appeared to increase from west to east suggesting that the more easterly populations had greater adaptation potential. We speculate that the more easterly populations are less likely to share genes since the prevailing winds are from the west. Germplasm from the more easterly populations may be used with suitable precautions within Alberta and possibly around Kamloops. Key words: Genetic distance, geographic distance, reclamation, potential adaptation

Potential adaptation strategies for rainfed soybean production in the south-eastern USA under climate change based on the CSM-CROPGRO-Soybean model

2015 ◽  
Vol 153 (5) ◽  
pp. 798-824 ◽  
Author(s):  
Y. BAO ◽  
G. HOOGENBOOM ◽  
R. W. McCLENDON ◽  
J. O. PAZ
Keyword(s):  
Climate Change ◽  
Adaptation Strategies ◽  
Climate Scenarios ◽  
The South ◽  
Soybean Production ◽  
Impact Of Climate Change ◽  
South Eastern ◽  
Eastern Usa ◽  
Potential Impact ◽  
Potential Adaptation

SUMMARYDue to the potential impact of climate change and climate variability on rainfed production systems, both farmers and policy makers will have to rely more on short- and long-term yield projections. The goal of this study was to develop a procedure for calibrating the Cropping System Model (CSM)-CROPGRO-Soybean model for six cultivars, to determine the potential impact of climate change on rainfed soybean for five locations in Georgia, USA, and to provide recommendations for potential adaptation strategies for soybean production in Georgia and other south-eastern states. The Genotype Coefficient Calculator (GENCALC) software package was applied for calibration of the soybean cultivar coefficients using variety trial data. The root mean square error (RMSE) between observed and simulated grain yield ranged from 201 to 413 kg/ha for the six cultivars. Generally, the future climate scenarios showed an increase in temperature which caused a decrease in the number of days to maturity for all varieties and for all locations. This will benefit late-planted soybean production slightly, while the increase in precipitation and carbon dioxide (CO2) concentration will result in a yield increase. This was the highest for Calhoun and Williamson and ranged from 31 to 49% for the climate change projections for 2050. However, a large reduction in precipitation caused a decrease in yield for Midville, especially based on the climate scenarios of the Global Climate Models (GCMs) Commonwealth Scientific and Industrial Research Organisation's model CSIRO-Mk3.0 and Geophysical Fluid Dynamics Laboratory's model GFDL-CM2.1. Overall, Calhoun, Williamson, Plains and Tifton will probably be more suitable for rainfed soybean production over the next 40 years than Midville. Farmers might shift to a later planting date, around 5 June, for the locations that were evaluated in the present study to avoid potential heat and drought stress during the summer months. The cultivars AG6702, AGS758RR and S80-P2 could be selected for rainfed soybean production since they had the highest rainfed yields among the six cultivars. In general, the present study showed that there are crop management options for soybean production in Georgia and the south-eastern USA that are adapted for the potential projected climate change conditions.

Demosthenes’ strategic maneuvering in the First Olynthiac

2021 ◽  
Vol 10 (3) ◽  
pp. 315-348
Author(s):  
Iva Svačinová
Keyword(s):  
Reference Point ◽  
Strategic Maneuvering ◽  
The People ◽  
Potential Adaptation

Abstract The article focuses on the analysis of Demosthenes’ strategic maneuvering in the First Olynthiac delivered in the Athenian Assembly of the People in 349 BC. It is a case study of the famous § 24 in which Demosthenes calls for the attack on Philip of Macedonia, based on a hypothetical reciprocal scenario: Philip would attack Athens in a similar situation. The first part of the paper offers an argumentative characterisation of the Assembly of the People. Subsequently, the historical and situational circumstances of the speech are described, and an argumentative reconstruction of Demosthenes’ speech is presented. The evaluation of the speech’s context serves as a reference point for the analysis of strategic maneuvering by putting forward the argument in § 24. The argument is analysed in terms of three strategic maneuvering aspects: choice of topical potential, adaptation to audience demands, and presentational devices.

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