scholarly journals The pleurogram, an under-investigated functional trait in seeds

2020 ◽  
Author(s):  
Ailton G Rodrigues-Junior ◽  
Carol C Baskin ◽  
Jerry M Baskin ◽  
Orlando C De-Paula
Keyword(s):  
Evolutionary History ◽  
Functional Trait ◽  
Water Entry ◽  
Structure And Function ◽  
Large Structure ◽  
Complete Model ◽  
Physical Dormancy ◽  
History Of ◽  
And Function ◽  
New Hypothesis

Abstract Background A structure called the pleurogram makes up a large part of the seed coat of some species in subfamilies Caesalpinioideae and Mimosoideae of Fabaceae, but little is known about its function. It has been hypothesized that this structure acts as a hygroscopic valve during the maturation drying of seeds. However, a new hypothesis has recently emerged that proposes a distinct function for the pleurogram. Scope Here, we provide an overview of the structure and function of the pleurogram, which is diverse and complex. This large structure can be dislodged, thereby creating a pathway for water entry into water-impermeable seeds. However, the pleurogram is non-functional as a pathway of water into the seed of some species. Thus, the evolutionary history of species with a pleurogram may be related to a loss/gain in its function. A complete model for the function of the pleurogram is proposed. Conclusions The pleurogram may act on several stages of the seed, from maturation to germination. As a hygroscopic valve, it regulates dehydration of the seed during maturation. As a pathway for water entry into the seed, the pleurogram acts as a water gap in seeds with physical dormancy, thereby regulating dormancy break/germination. The occurrence of a pleurogram in several genera of legumes and Cucurbitaceae is confirmed. Single or multiple pleurograms can serve as (the) point(s) of water entry into seeds that do not otherwise have a hilar water gap.

scholarly journals Exploring the evolutionary history of centrosomes

2014 ◽  
Vol 369 (1650) ◽  
pp. 20130453 ◽  
Author(s):  
Juliette Azimzadeh
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Evolutionary History ◽  
Structural Diversity ◽  
Structure And Function ◽  
Different Types ◽  
History Of ◽  
Tight Association ◽  
And Function ◽  
Molecular Components

The centrosome is the main organizer of the microtubule cytoskeleton in animals, higher fungi and several other eukaryotic lineages. Centrosomes are usually located at the centre of cell in tight association with the nuclear envelope and duplicate at each cell cycle. Despite a great structural diversity between the different types of centrosomes, they are functionally equivalent and share at least some of their molecular components. In this paper, we explore the evolutionary origin of the different centrosomes, in an attempt to understand whether they are derived from an ancestral centrosome or evolved independently from the motile apparatus of distinct flagellated ancestors. We then discuss the evolution of centrosome structure and function within the animal lineage.

scholarly journals The plant circadian clock influences rhizosphere community structure and function

2017 ◽  
Author(s):  
Charley J. Hubbard ◽  
Marcus T. Brock ◽  
Linda T.A. van Diepen ◽  
Loïs Maignien ◽  
Brent E. Ewers ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Circadian Clock ◽  
Structure And Function ◽  
Plant Performance ◽  
Wild Type ◽  
Night Time ◽  
History Of ◽  
And Function ◽  
Rhizosphere Community

AbstractPlants alter chemical and physical properties of soil, and thereby influence rhizosphere microbial community structure. The structure of microbial communities may in turn affect plant performance. Yet, outside of simple systems with pairwise interacting partners, the plant genetic pathways that influence microbial community structure remain largely unknown, as are the performance feedbacks of microbial communities selected by the host plant genotype. We investigated the role of the plant circadian clock in shaping rhizosphere community structure and function. We performed 16S rRNA gene sequencing to characterize rhizosphere bacterial communities of Arabidopsis thaliana between day and night time points, and tested for differences in community structure between wild-type (Ws) vs. clock mutant (toc1-21, ztl-30) genotypes. We then characterized microbial community function, by growing wild-type plants in soils with an overstory history of Ws, toc1-21 or ztl-30 and measuring plant performance. We observed that rhizosphere community structure varied between day and night time points, and clock misfunction significantly altered rhizosphere communities. Finally, wild-type plants germinated earlier and were larger when inoculated with soils having an overstory history of wild-type in comparison to clock mutant genotypes. Our findings suggest the circadian clock of the plant host influences rhizosphere community structure and function.

Mass Extinctions and the Structure and Function of Ecosystems

2013 ◽  
Vol 19 ◽  
pp. 115-156 ◽  
Author(s):  
Pincelli M. Hull ◽  
Simon A. F. Darroch
Keyword(s):  
Biodiversity Loss ◽  
Structure And Function ◽  
Ecosystem Change ◽  
Mass Extinctions ◽  
General Introduction ◽  
Biodiversity Crisis ◽  
Ecosystem Effects ◽  
History Of ◽  
Research Questions ◽  
And Function

Mass extinctions shape the history of life and can be used to inform understanding of the current biodiversity crisis. In this paper, a general introduction is provided to the methods used to investigate the ecosystem effects of mass extinctions (Part I) and to explore major patterns and outstanding research questions in the field (Part II). The five largest mass extinctions of the Phanerozoic had profoundly different effects on the structure and function of ecosystems, although the causes of these differences are currently unclear. Outstanding questions and knowledge gaps are identified that need to be addressed if the fossil record is to be used as a means of informing the dynamics of future biodiversity loss and ecosystem change.

scholarly journals The evolutionary history of haptophytes and cryptophytes: phylogenomic evidence for separate origins

2012 ◽  
Vol 279 (1736) ◽  
pp. 2246-2254 ◽  
Author(s):  
Fabien Burki ◽  
Noriko Okamoto ◽  
Jean-François Pombert ◽  
Patrick J. Keeling
Keyword(s):  
Evolutionary History ◽  
Expressed Sequence Tag ◽  
Level Data ◽  
Guillardia Theta ◽  
History Of ◽  
The Common ◽  
Genome Level ◽  
Phylogenomic Analyses ◽  
New Hypothesis ◽  
Expressed Sequence

An important missing piece in the puzzle of how plastids spread across the eukaryotic tree of life is a robust evolutionary framework for the host lineages. Four assemblages are known to harbour plastids derived from red algae and, according to the controversial chromalveolate hypothesis, these all share a common ancestry. Phylogenomic analyses have consistently shown that stramenopiles and alveolates are closely related, but haptophytes and cryptophytes remain contentious; they have been proposed to branch together with several heterotrophic groups in the newly erected Hacrobia. Here, we tested this question by producing a large expressed sequence tag dataset for the katablepharid Roombia truncata , one of the last hacrobian lineages for which genome-level data are unavailable, and combined this dataset with the recently completed genome of the cryptophyte Guillardia theta to build an alignment composed of 258 genes. Our analyses strongly support haptophytes as sister to the SAR group, possibly together with telonemids and centrohelids. We also confirmed the common origin of katablepharids and cryptophytes, but these lineages were not related to other hacrobians; instead, they branch with plants. Our study resolves the evolutionary position of haptophytes, an ecologically critical component of the oceans, and proposes a new hypothesis for the origin of cryptophytes.

Staging and Embodiment of the Tragic in Pina Bausch's Orpheus and Eurydice (1975)

2016 ◽  
Vol 2016 ◽  
pp. 191-197
Author(s):  
Nicole Haitzinger
Keyword(s):  
Twentieth Century ◽  
Structure And Function ◽  
Dance Studies ◽  
Central European ◽  
Orpheus And Eurydice ◽  
Mise En Scene ◽  
History Of ◽  
Longue Duree ◽  
Longue Durée ◽  
And Function

This paper is concerned with resonances of the tragic in twentieth-century central-European dance theatet, to be discussed with particular reference to Pina Bausch's 1975 Orpheus and Eurydice. In my study Resonances of the Tragic: Between Event and Affect (2015), I have argued that in terms of a history of the “longue durée,” the evocation of the tragic occurs in a field of tension between technique, the mise-en-scène, and conceptions, as well as procedures and moments of interruption, of suspension, of disruption and of the indeterminable resulting from ecstatic corporeality. Its structure and function can generate an event in the emphatic sense of the term; consequently, it provides a paradigm for recognizing structures of form and of an aesthetic of reception, structures emerging from individual constellations of the fictional and choric, absence and presence. From the perspective of dance studies, the tragic emanates from the representation of horrendous monstrosity testing the limits of what can be imagined by means of the moved body in all senses of the word; but how exactly does Bausch produce the qualities of the ambivalent, ambiguous, and paradoxical—and, consequently, the tragic?

Commentary on “Reflections on culture, structure and function of an intensive support service centred on positive behavioural support”

2016 ◽  
Vol 21 (4) ◽  
pp. 212-219 ◽  
Author(s):  
Sandy Toogood
Keyword(s):  
Support Service ◽  
Structure And Function ◽  
Content Type ◽  
Behavioural Support ◽  
Wide Range ◽  
Service Models ◽  
History Of ◽  
Positive Behaviour Support ◽  
The Uk ◽  
And Function

Purpose The purpose of this paper is to provide a commentary on Patterson and Berry’s paper “Reflections on culture, structure and function of an intensive support service centred on positive behavioural support”. Design/methodology/approach This paper reviews key ideas presented in Patterson and Berry’s article relative to the recent history of service delivery in the UK and the growing interest being shown in positive behaviour support. Findings Patterson and Berry’s article adds to a modest literature on specialist support services and should stimulate further descriptions of service models and the concepts underpinning them. Originality/value The literature on specialist support service models is limited and this addition should be relevant to a wide range of clinicians, consumers and commissioners.

scholarly journals Soul searching: a brief history of the mind/body debate in the neurosciences

2007 ◽  
Vol 23 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Brian Dolan
Keyword(s):  
Early Modern ◽  
Structure And Function ◽  
The Self ◽  
History Of Neuroscience ◽  
History Of ◽  
And Function ◽  
The Mind ◽  
The Brain ◽  
The Way

✓Anatomical and physiological understandings of the structure and function of the brain have worked to establish it as the “seat of the soul.” As an organ of reflection, meditation, and memory, the brain becomes synonymous with what defines the “self” through the existence of consciousness—of mind. Thus, the brain has been associated with a range of transcendent concepts—the soul, spirit, mind, and consciousness—that all relate in fundamental ways to each other both in terms of their perceived location within the brain and because of the way each works ultimately to define the person to whom the brain belongs. In this article, the author provides a brief exploration of how interrelated these categories have been when seen in the context of ancient, Renaissance, early modern, and modern philosophical and medical concerns; how the brain has variously been perceived as home to these intimate states of being; and how practitioners from the neurosciences have reflected on these questions. The author provides novel insights into the interrelationships of philosophy, theology, and medicine by examining these issues through the lens of the history of neuroscience.

The history of the capillary wall: doctors, discoveries, and debates

2007 ◽  
Vol 293 (5) ◽  
pp. H2667-H2679 ◽  
Author(s):  
Charlotte Hwa ◽  
William C. Aird
Keyword(s):  
Basic Structure ◽  
Structure And Function ◽  
The Body ◽  
Capillary Wall ◽  
Central Importance ◽  
Definitive Evidence ◽  
Arterial Blood ◽  
History Of ◽  
And Function

In 1628, William Harvey provided definitive evidence that blood circulates. The notion that blood travels around the body in a circle raised the important question of how nutrients pass between blood and underlying tissue. Perhaps, Harvey posited, arterial blood pours into the flesh as into a sponge, only then to find its way into the veins. Far from solving this problem, Marcello Malpighi's discovery of the capillaries in 1661 only added to the dilemma: surely, some argued, these entities are little more than channels drilled into tissues around them. As we discuss in this review, it would take over 200 years to arrive at a consensus on the basic structure and function of the capillary wall. A consideration of the history of this period provides interesting insights into not only the central importance of the capillary as a focus of investigation, but also the enormous challenges associated with studying these elusive structures.

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