scholarly journals The Role of Chloroplast Membrane Lipid Metabolism in Plant Environmental Responses

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 706
Author(s):  
Ron Cook ◽  
Josselin Lupette ◽  
Christoph Benning
Keyword(s):  
Environmental Conditions ◽  
Environmental Changes ◽  
Photosynthetic Apparatus ◽  
Life Forms ◽  
Membrane Lipid ◽  
Chloroplast Membrane ◽  
Class Composition ◽  
Environmental Responses

Plants are nonmotile life forms that are constantly exposed to changing environmental conditions during the course of their life cycle. Fluctuations in environmental conditions can be drastic during both day–night and seasonal cycles, as well as in the long term as the climate changes. Plants are naturally adapted to face these environmental challenges, and it has become increasingly apparent that membranes and their lipid composition are an important component of this adaptive response. Plants can remodel their membranes to change the abundance of different lipid classes, and they can release fatty acids that give rise to signaling compounds in response to environmental cues. Chloroplasts harbor the photosynthetic apparatus of plants embedded into one of the most extensive membrane systems found in nature. In part one of this review, we focus on changes in chloroplast membrane lipid class composition in response to environmental changes, and in part two, we will detail chloroplast lipid-derived signals.

scholarly journals The crucial role of genome-wide genetic variation in conservation

2021 ◽  
Vol 118 (48) ◽  
pp. e2104642118
Author(s):  
Marty Kardos ◽  
Ellie E. Armstrong ◽  
Sarah W. Fitzpatrick ◽  
Samantha Hauser ◽  
Philip W. Hedrick ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Environmental Changes ◽  
Population Viability ◽  
Adaptive Potential ◽  
Biodiversity Crisis ◽  
Genome Wide ◽  
Simulation Based ◽  
Functional Genetic Variation

The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation biology has placed too much focus on conserving genome-wide genetic variation, and that the field should instead focus on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations toward extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide genetic variation on long-term population viability will only worsen the biodiversity crisis.

An On-Going Monitoring Project of a New Timber Structure

2013 ◽  
Vol 778 ◽  
pp. 757-764 ◽  
Author(s):  
Francesca Lanata
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Construction Material ◽  
Structural Response ◽  
Timber Structures ◽  
The Real ◽  
Structural Health

Structural design, regardless of construction material, is based mainly on deterministic codes that partially take into account the real structural response under service and environmental conditions. This approach can lead to overdesigned (and expensive) structures. The differences between the designed and the real behaviors are usually due to service loads not taken into account during the design or simply to the natural degradation of materials properties with time. This is particularly true for wood, which is strongly influenced by service and environmental conditions. Structural Health Monitoring can improve the knowledge of timber structures under service conditions, provide information on material aging and follow the degradation of the overall building performance with time.A long-term monitoring control has been planned on a three-floor structure composed by wooden trusses and composite concrete-wood slabs. The structure is located in Nantes, France, and it is the new extension to the Wood Science and Technology Academy (ESB). The main purpose of the monitoring is to follow the long-term structural response from a mechanical and energetic point of view, particularly during the first few service years. Both static and dynamic behavior is being followed through strain gages and accelerometers. The measurements will be further put into relation with the environmental changes, temperature and humidity in particular, and with the operational charges with the aim to improve the comprehension of long-term performances of wooden structures under service. The goal is to propose new improved and optimized methods to make timber constructions more efficient compared to other construction materials (masonry, concrete, steel).The paper will mainly focus on the criteria used to design the architecture of the monitoring system, the parameters to measure and the sensors to install. The first analyses of the measurements will be presented at the conference to have a feedback on the performance of the installed sensors and to start to define a general protocol for the Structural Health Monitoring of such type of timber structures.

scholarly journals Genome-wide fitness assessment during diurnal growth reveals an expanded role of the cyanobacterial circadian clock protein KaiA

2018 ◽  
Vol 115 (30) ◽  
pp. E7174-E7183 ◽  
Author(s):  
David G. Welkie ◽  
Benjamin E. Rubin ◽  
Yong-Gang Chang ◽  
Spencer Diamond ◽  
Scott A. Rifkin ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Continuous Light ◽  
Axial Rotation ◽  
Time Of Day ◽  
Negative Regulator ◽  
Photosynthetic Organisms ◽  
Environmental Responsiveness ◽  
Environmental Responses ◽  
Clock Protein

The recurrent pattern of light and darkness generated by Earth’s axial rotation has profoundly influenced the evolution of organisms, selecting for both biological mechanisms that respond acutely to environmental changes and circadian clocks that program physiology in anticipation of daily variations. The necessity to integrate environmental responsiveness and circadian programming is exemplified in photosynthetic organisms such as cyanobacteria, which depend on light-driven photochemical processes. The cyanobacterium Synechococcus elongatus PCC 7942 is an excellent model system for dissecting these entwined mechanisms. Its core circadian oscillator, consisting of three proteins, KaiA, KaiB, and KaiC, transmits time-of-day signals to clock-output proteins, which reciprocally regulate global transcription. Research performed under constant light facilitates analysis of intrinsic cycles separately from direct environmental responses but does not provide insight into how these regulatory systems are integrated during light–dark cycles. Thus, we sought to identify genes that are specifically necessary in a day–night environment. We screened a dense bar-coded transposon library in both continuous light and daily cycling conditions and compared the fitness consequences of loss of each nonessential gene in the genome. Although the clock itself is not essential for viability in light–dark cycles, the most detrimental mutations revealed by the screen were those that disrupt KaiA. The screen broadened our understanding of light–dark survival in photosynthetic organisms, identified unforeseen clock–protein interaction dynamics, and reinforced the role of the clock as a negative regulator of a nighttime metabolic program that is essential for S. elongatus to survive in the dark.

scholarly journals Pleistocene Branchiopods (Cladocera, Anostraca) from Transbaikalian Siberia Demonstrate Morphological and Ecological Stasis

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3063
Author(s):  
Anton A. Zharov ◽  
Anna N. Neretina ◽  
D. Christopher Rogers ◽  
Svetlana A. Reshetova ◽  
Sofia M. Sinitsa ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Seasonal Variations ◽  
Environmental Changes ◽  
Daphnia Pulex ◽  
Steppe Zone ◽  
Water Bodies ◽  
Large Branchiopods ◽  
Community Types ◽  
High Diversity

Pleistocene water bodies have been studied using the paleolimnological approach, which traces environmental changes using particular subfossils as ecological proxies, rather than analysis of the paleocommunities themselves. Within a given taphocoenosis, the presence and quantity of animals are related to environmental conditions rather than to community types where relationships between taxa are stabilized during their long-term co-occurrence and are (at least partially) more important than the particular environmental conditions at the time of deposition, which may have experienced significant seasonal and inter-seasonal variations. Here, we analyze Branchiopoda (Crustacea) of two paleolocalities in the Transbaikalian Region of Russia: Urtuy (MIS3) and Nozhiy (older than 1.5 million years). Cladocerans Daphnia (Ctenodaphnia) magna, D. (C.) similis, D. (Daphnia) pulex, Ceriodaphnia pulchella-reticulata, C. laticaudata, Simocephalus sp., Moina cf. brachiata, M. macropopa clade, Chydorus cf. sphaericus, Capmtocercus sp. and anostracans Branchinecta cf. paludosa, and Streptocephalus (Streptocephalus) sp. are found in two localities. With the exception of the last taxon, which now occurs in the southern Holarctic, all other taxa inhabit the Transbaikalian Region. Within Eurasia, the steppe zone has the greatest diversity of large branchiopods and a high diversity of some cladocerans, such as subgenus Daphnia (Ctenodaphnia) and Moina sp. Here we demonstrated that the branchiopod community in shallow steppe water bodies has been unchanged since at least the Pleistocene, demonstrating long-term morphological and ecological stasis.

AN EXPLORATORY STUDY OF STRATEGIC PLANNING BEHAVIOUR IN SMEs IN SINGAPORE/MALAYSIA CONTEXT

1993 ◽  
Vol 01 (02) ◽  
pp. 255-278 ◽  
Author(s):  
B C GHOSH ◽  
AIK-MENG LOW ◽  
TECK-MENG TAN ◽  
CHEE-ONN CHAN
Keyword(s):  
Strategic Planning ◽  
Risk Taking ◽  
Exploratory Study ◽  
Environmental Changes ◽  
Information Gathering ◽  
Extensive Literature ◽  
Chief Executives ◽  
Spouse Support

Strategic planning literature is extensive but how small and medium sized firms (SMEs) behave in response to environmental changes and how they incorporate such changes in their medium to long term plan has been insufficiently studied, in the writers’ view, especially in Singapore/Malaysia context. This research is dedicated towards finding a framework for such analysis and testing such framework in 15 local/regional companies. After an extensive literature review from sources which are both international and local, a fairly lengthy questionnaire was developed. As stated, 15 companies’ chief executives (or in their absence, someone equivalent) were interviewed and at the end of each interview a set of structured questions were asked to be filled in. The whole interview process itself took more than a month. The results have been analysed and highlighted. One main finding is that SMEs continue to be family-centred in a local/regional context especially. Among other findings were the process of information gathering which was chiefly informal, the dominance of CEO-centred management, opportunity-seeking and risk-taking in identifying strategies and finally, the role of the spouse-support. This research is multi-faced and deserves to be further explored. Herein lies its limitation as well as its promise. A research of this nature cannot claim to be fully conclusive and hence its natural incompleteness indicates further research continuation.

Soil organisms and sustainable productivity

Soil Research ◽  
1992 ◽  
Vol 30 (6) ◽  
pp. 855 ◽  
Author(s):  
KE Lee ◽  
CE Pankhurst
Keyword(s):  
Nutrient Cycling ◽  
Life Forms ◽  
Soil Microflora ◽  
Soil Biota ◽  
Soil Organisms ◽  
Soil Organism ◽  
The Impact ◽  
Sustainable Productivity

The soil is a habitat for a vast, complex and interactive community of soil organisms whose activities largely determine the chemical and physical properties of the soil. In a fertile soil the soil biota may have a biomass exceeding 20 t ha-1, with life forms ranging from microscopic bacteria to the largest of earthworms which may be 1 m in length. Only a small fraction, probably <20%, of the soil microflora and microfauna (including bacteria, fungi, algae, protozoa, nematodes, collembola, acari) have been described. The role of soil organisms in the development and maintenance of soil structure, in nutrient cycling and in their various interactions (including associative, harmful and beneficial) with plant roots is described. Trophic interactions between soil organism groups in developed agroecosystems are considered in relation to nutrient cycling and the impact such interactions have on populations of saprophytic, parasitic and symbiotic microorganisms. Prospects for the management of the soil biota to promote sustainable productivity are illustrated by describing the effects of tillage on the composition of soil organism communities. Management technologies that conserve the biodiversity of communities may provide the greatest benefits for the long term sustainability of the soil resource.

scholarly journals DNA from lake sediments reveals the long-term dynamics and diversity of <i>Synechococcus</i> assemblages

2013 ◽  
Vol 10 (6) ◽  
pp. 3817-3838 ◽  
Author(s):  
I. Domaizon ◽  
O. Savichtcheva ◽  
D. Debroas ◽  
F. Arnaud ◽  
C. Villar ◽  
...  
Keyword(s):  
16S Rrna ◽  
Environmental Conditions ◽  
Trophic Status ◽  
Community Dynamics ◽  
Environmental Changes ◽  
Quantitative Polymerase Chain Reaction ◽  
Additive Models ◽  
Phosphorus Concentration ◽  
Rrna Gene

Abstract. While picocyanobacteria (PC) are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes). In particular, we investigated the long-term (100 yr) diversity and dynamics of Synechococcus,, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided the ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR; quantitative Polymerase Chain Reaction) results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus, (fraction of Synechococcus, in total cyanobacteria). The diversity of Synechococcus, in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and the following internally transcribed spacer (ITS). Up to 23 different OTUs (based on 16S rRNA), which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, the study of ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (in temperature and phosphorus concentration) affected Synechococcus, community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus, clusters. Providing such novel insights into the long-term history of an important group of primary producers, this study illustrates the promising approach that consists in coupling molecular tools and paleolimnology to reconstruct a lake's biodiversity history.

scholarly journals Memory, not just perception, plays an important role in terrestrial mammalian migration

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170449 ◽  
Author(s):  
Chloe Bracis ◽  
Thomas Mueller
Keyword(s):  
Simulation Model ◽  
Environmental Conditions ◽  
Migration Routes ◽  
Clear Signal ◽  
Individual Based Simulation ◽  
Underlying Mechanisms ◽  
With Memory ◽  
Key Questions

One of the key questions regarding the underlying mechanisms of mammalian land migrations is how animals select where to go. Most studies assume perception of resources as the navigational mechanism. The possible role of memory that would allow forecasting conditions at distant locations and times based on information about environmental conditions from previous years has been little studied. We study migrating zebra in Botswana using an individual-based simulation model, where perceptually guided individuals use currently sensed resources at different perceptual ranges, while memory-guided individuals use long-term averages of past resources to forecast future conditions. We compare simulated individuals guided by perception or memory on resource landscapes of remotely sensed vegetation data to trajectories of GPS-tagged zebras. Our results show that memory provides a clear signal that best directs migrants to their destination compared to perception at even the largest perceptual ranges. Zebras modelled with memory arrived two to four times, or up to 100 km, closer to the migration destination than those using perception. We suggest that memory in addition to perception is important for directing ungulate migration. Furthermore, our findings are important for the conservation of migratory mammals, as memory informing direction suggests migration routes could be relatively inflexible.

scholarly journals The crucial role of genome-wide genetic variation in conservation

2021 ◽  
Author(s):  
Martin Kardos ◽  
Ellie Armstrong ◽  
Sarah W Fitzpatrick ◽  
Samantha Hauser ◽  
Philip Hedrick ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Environmental Changes ◽  
Population Viability ◽  
Adaptive Potential ◽  
Biodiversity Crisis ◽  
Genome Wide ◽  
Simulation Based ◽  
Functional Genetic Variation

The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation biology has placed too much focus on the conservation of genome-wide genetic variation, and that this approach should be replaced with another that focuses instead on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that the conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations towards extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide variation on long-term population viability will only worsen the biodiversity crisis.

The resistance of viable permafrost algae to simulated environmental stresses: implications for astrobiology

2003 ◽  
Vol 2 (3) ◽  
pp. 171-177 ◽  
Author(s):  
T.A. Vishnivetskaya ◽  
E.V. Spirina ◽  
A.V. Shatilovich ◽  
L.G. Erokhina ◽  
E.A. Vorobyova ◽  
...  
Keyword(s):  
Green Algae ◽  
Algal Species ◽  
Photosynthetic Apparatus ◽  
Morphological Characteristics ◽  
Life Forms ◽  
Bacterial Cells ◽  
Short Term ◽  
Ecological Importance ◽  
Siberian Permafrost

54 strains of viable green algae and 26 strains of viable cyanobacteria were recovered from 128 and 56 samples collected from Siberian and Antarctic permafrost, respectively, with ages from modern to a few million years old. Although species of unicellular green algae belonged to Chlorococcales were subdominant inside permafrost, green algae Pedinomonas sp. were observed in Antarctic permafrost. Filamentous cyanobacteria of Oscillatoriales, Nostocales were just found in Siberian permafrost. Algal biomass in the permanently frozen sediments, expressed as concentration of chlorophyll a, was 0.06–0.46 μg g−1. The number of viable algal cells varied between <102 and 9×103 cfu g−1, but the number of viable bacterial cells was usually higher from 102 to 9.2×105 cfu g−1. Frozen but viable permafrost algae have preserved their morphological characteristics and photosynthetic apparatus in the dark permafrost. In the laboratory, they restored their photosynthetic activity, growth and development in favourable conditions at positive temperatures and with the availability of water and light. The discovery of ancient viable algae within permafrost reflects their ability to tolerate long-term freezing. In this study, the tolerance of algae and cyanobacteria to freezing, thawing and freezing–drying stresses was evaluated by short-term (days to months) low-temperature experiments. Results indicate that viable permafrost microorganisms demonstrate resistance to such stresses. Apart from their ecological importance, the bacterial and algal species found in permafrost have become the focus for novel biotechnology, as well as being considered proxies for possible life forms on cryogenic extraterrestrial bodies.

Sign in / Sign up

Export Citation Format

Share Document