scholarly journals Visualizing Biological Membrane Organization and Dynamics

2019 ◽  
Author(s):  
Marc Baaden
Keyword(s):  
Nervous System ◽  
Natural Selection ◽  
Biological Membrane ◽  
Membrane Organization ◽  
Modern Biology ◽  
Biological Objects ◽  
First Time ◽  
Insect Eye ◽  
Camillo Golgi ◽  
Dioptric Apparatus

Biological membranes are fascinating. Santiago Ramón y Cajal, who received the Nobel prize in 1906 together with Camillo Golgi for their work on the nervous system, wrote “[..]in the study of this membrane[..] I felt more profoundly than in any other subject of study the shuddering sensation of the unfathomable mystery of life”[1]. The visualization and conceptualization of these biological objects have profoundly shaped many aspects of modern biology, drawing inspiration from experiments, computer simulations, as well as from the imagination of scientists and artists. The aim of this review is to provide a fresh look on current ideas of biological membrane organization and dynamics by discussing selected examples across fields [1] The full quotation is “I must not conceal the fact that in the study of this membrane I for the first time felt my faith in Darwinism (hypothesis of natural selection) weakened, being amazed and confounded by the supreme constructive ingenuity revealed not only in the retina and in the dioptric apparatus of the vertebrates but even in the meanest insect eye. There, in fine, I felt more profoundly than in any other subject of study the shuddering sensation of the unfathomable mystery of life.” from the autobiography Recollections of My Life.

scholarly journals Drosophila Stathmin: A Microtubule-destabilizing Factor Involved in Nervous System Formation

2002 ◽  
Vol 13 (2) ◽  
pp. 698-710 ◽  
Author(s):  
Sylvie Ozon ◽  
Antoine Guichet ◽  
Olivier Gavet ◽  
Siegfried Roth ◽  
André Sobel
Keyword(s):  
Nervous System ◽  
System Development ◽  
Nervous System Development ◽  
Microtubule Assembly ◽  
Nervous Systems ◽  
Germ Cell Migration ◽  
Numerous Cell ◽  
First Time

Stathmin is a ubiquitous regulatory phosphoprotein, the generic element of a family of neural phosphoproteins in vertebrates that possess the capacity to bind tubulin and interfere with microtubule dynamics. Although stathmin and the other proteins of the family have been associated with numerous cell regulations, their biological roles remain elusive, as in particular inactivation of the stathmin gene in the mouse resulted in no clear deleterious phenotype. We identified stathmin phosphoproteins inDrosophila, encoded by a unique gene sharing the intron/exon structure of the vertebrate stathmin andstathmin family genes. They interfere with microtubule assembly in vitro, and in vivo when expressed in HeLa cells. Drosophila stathmin expression is regulated during embryogenesis: it is high in the migrating germ cells and in the central and peripheral nervous systems, a pattern resembling that of mammalian stathmin. Furthermore, RNA interference inactivation ofDrosophila stathmin expression resulted in germ cell migration arrest at stage 14. It also induced important anomalies in nervous system development, such as loss of commissures and longitudinal connectives in the ventral cord, or abnormal chordotonal neuron organization. In conclusion, a single Drosophilagene encodes phosphoproteins homologous to the entire vertebrate stathmin family. We demonstrate for the first time their direct involvement in major biological processes such as development of the reproductive and nervous systems.

NO nerves in a tapeworm. NADPH-diaphorase histochemistry in adult Hymenolepis diminuta

Parasitology ◽  
1996 ◽  
Vol 113 (6) ◽  
pp. 559-565 ◽  
Author(s):  
M. K. S. Gustafsson ◽  
A. M. Lindholm ◽  
N. B. Terenina ◽  
M. Reuter
Keyword(s):  
Nitric Oxide ◽  
Nervous System ◽  
Nadph Diaphorase ◽  
Hymenolepis Diminuta ◽  
Staining Reaction ◽  
Internal Seminal Vesicle ◽  
Oxide Synthase ◽  
First Time ◽  
The Brain ◽  
Nerve Cords

SUMMARYThe free radical nitric oxide (NO), which is synthesized by nitric oxide synthase (NOS), has recently been discovered to function as a neuronal messenger. The presence of NOS was detected in the nervous system of adult Hymenolepis diminuta with NADPH-diaphorase (NADPH-d) histochemistry. The NADPH-d histochemical reaction is regarded as a selective marker for NOS in neuronal tissue. NADPH-d staining was observed in nerve fibres in the main and minor nerve cords and the transverse ring commissures, and in cell bodies in the brain commissure, along the main nerve cords, in the suckers and the rostellar sac. NADPH-d staining was also observed in the wall of the internal seminal vesicle and the genital atrium. The pattern of NADPH-d staining was compared with that of the 5-HT immunoreactive nervous elements. The NADPH-d staining reaction and the 5-HT immunoreactivity occur in separate sets of neurons. This is the first time the NADPH-d reaction has been demonstrated in the nervous system of a flatworm, indicating that NOS is present and that NO can be produced at this level of evolution.

What is the Evolutionary Advantage of Migraine?

Cephalalgia ◽  
2002 ◽  
Vol 22 (8) ◽  
pp. 624-632 ◽  
Author(s):  
E Loder
Keyword(s):  
Nervous System ◽  
Natural Selection ◽  
Environmental Factors ◽  
Genetic Factors ◽  
Evolutionary Perspective ◽  
Defence Mechanism ◽  
Design Constraint ◽  
Trade Off ◽  
Evolutionary Advantage ◽  
Evolutionary Explanations

Susceptibility to migraine is determined by genetic factors and is therefore subject to the forces of natural selection. Migraine is a common and ancient disorder whose prevalence may be increasing, suggesting that a migraine-prone nervous system may be associated with reproductive or survival advantages. Five evolutionary explanations are reviewed that might account for the persistence of migraine: (i) migraine as a defence mechanism; (ii) migraine as a result of conflict with other organisms; (iii) migraine as result of novel environmental factors; (iv) migraine as a trade-off between genetic harms and benefits; and (v) migraine as a design constraint. An evolutionary perspective on migraine allows the generation of important hypotheses about the disorder and suggests rewarding possibilities for further research.

scholarly journals Statistical assessment of ecological invariants of plant cover and the possibility of estimating invariants in the taxonomy of plants

2021 ◽  
Vol 20 (1) ◽  
pp. 401-403
Author(s):  
B. I. Semkin ◽  
L. I. Varchenko
Keyword(s):  
Statistical Methods ◽  
Plant Cover ◽  
Leningrad Region ◽  
Statistical Assessment ◽  
Biological Objects ◽  
First Time

In this work, for the first time, ecological invariants for the dry polydominant cereal-forb meadow of theKarelian Isthmus of the Leningrad region and taxonomic invariants of three species of Heracleum L. are determined. It isproposed to use the developed statistical methods for evaluating invariants to differentiate biological objects at all levels ofbiota: molecular, subcellular, cellular, organismic, population, coenotic and ecological.

scholarly journals Humoral regulation of neuromuscular transmission and neurotrophic control of skeletal muscle fiber

2001 ◽  
Vol 82 (5) ◽  
pp. 321-325
Author(s):  
G. I. Poletaev
Keyword(s):  
Skeletal Muscle ◽  
Nervous System ◽  
Muscle Fiber ◽  
Neuromuscular Transmission ◽  
Chemical Nature ◽  
Focus Of Attention ◽  
Skeletal Muscle Fiber ◽  
Neurotrophic Control ◽  
First Time ◽  
Humoral Regulation

The mechanism of nerve-to-muscle transmission, as well as the trophic influence of the nervous system on effector organs, have always been in the focus of attention of scientists of the Kazan physiological school. Suffice it to recall the famous physiologist A.F. Samoilov, who in 1924 for the first time established the chemical nature of neuromuscular transmission.

scholarly journals Marcello Malpighi: the nervous system under a microscope

2021 ◽  
Vol 79 (4) ◽  
pp. 346-349
Author(s):  
Eliasz ENGELHARDT
Keyword(s):  
Nervous System ◽  
Gross Anatomy ◽  
Considerable Improvement ◽  
Microscopic Anatomy ◽  
New Era ◽  
Microscopic Studies ◽  
Staining Techniques ◽  
Histological Processing ◽  
The 19Th Century ◽  
First Time

ABSTRACT The longstanding study of gross anatomy experienced a considerable improvement with the advent of the microscope in the early 17th century. The representative personality of this new era certainly was Marcello Malpighi, seen as “founder of microscopic anatomy”. He studied, with a rudimentary compound microscope, numerous tissues and organs of several classes of animals, as well as plants. He described, for the first time, the microscopic structure of the nervous system, identifying in the gray matter of its various levels minute elements he took as “glands”. It should be reminded that the concept of “cell” (and “nerve cell”) was unknown at his time. Many researchers followed, performing microscopic studies, but without better results, and Malpighi’s view was maintained until the beginning of the 19th century, when new histological processing and staining techniques appeared, as well as improved microscopes.

Limbic System-Frontal Lobes' Role in Subtypes of “Atypical Rape”

1988 ◽  
Vol 63 (3) ◽  
pp. 879-888 ◽  
Author(s):  
Anneliese A. Pontius
Keyword(s):  
Nervous System ◽  
Temporal Lobe ◽  
Brain Electrical Activity ◽  
Age Group ◽  
Specific Stimulus ◽  
Brain Electrical Activity Mapping ◽  
Trigger Stimulus ◽  
Extreme Change ◽  
Alteration Of Consciousness ◽  
First Time

Two possible subtypes of fronto-limbic dysfunctioning are implicated in certain cases of rape involving extreme change in the perpetrator's sexual preference regarding the victim's gender, age group or kind of sexual act: (1) temporal lobe epilepsy, supported by electroencephalogram and brain electrical activity mapping (BEAM), both showing bilateral temporal lobe dysfunction, left more than right, and (2) a newly proposed Limbic Psychotic Trigger Reaction which is reminiscent of “kindling”: a moderate, though frequently repeated experience is suddenly revived by a specific stimulus, unwittingly provided by a stranger, the victim-to-be. The trigger stimulus evokes a sudden (20 min. long) seizure-like episode, typically with first-time hallucinations and autonomic nervous system symptoms, and there is no (significant) alteration of consciousness with full recall of the sexual and/or homicidal attack.

Dephrin, a transmembrane ephrin with a unique structure, prevents interneuronal axons from exiting the Drosophila embryonic CNS

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4205-4218 ◽  
Author(s):  
Torsten Bossing ◽  
Andrea H. Brand
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Ectopic Expression ◽  
Axonal Pathfinding ◽  
N Terminus ◽  
Outer Border ◽  
Embryonic Cns ◽  
First Time ◽  
Neuronal Compartments

Ephrin/Eph signalling is crucial for axonal pathfinding in vertebrates and invertebrates. We identified the Drosophila ephrin orthologue, Dephrin, and describe for the first time the role of ephrin/Eph signalling in the embryonic central nervous system (CNS). Dephrin is a transmembrane ephrin with a unique N terminus and an ephrinB-like cytoplasmic tail. Dephrin binds and interacts with DEph, the Drosophila Eph-like receptor, and Dephrin and DEph are confined to different neuronal compartments. Loss of Dephrin or DEph causes the abberant exit of interneuronal axons from the CNS, whereas ectopic expression of Dephrin halts axonal growth. We propose that the longitudinal tracts in the Drosophila CNS are moulded by a repulsive outer border of Dephrin expression.

2. Evolution and natural selection

2019 ◽  
pp. 9-26
Author(s):  
Samir Okasha
Keyword(s):  
Natural Selection ◽  
Charles Darwin ◽  
Natural World ◽  
Early 20Th Century ◽  
Philosophical Argument ◽  
Modern Biology ◽  
Theory Of Evolution ◽  
Philosophical Significance ◽  
Argument From Design ◽  
Evolution By Natural Selection

In 1859 Charles Darwin published On the Origin of Species, in which he set out his theory of evolution. The book marked a turning point in our understanding of the natural world and revolutionized biology. ‘Evolution and natural selection’ outlines the theory of evolution by natural selection, explaining its unique status in biology and its philosophical significance. It considers how Darwin’s theory undermined the ‘argument from design’, a traditional philosophical argument for the existence of God; how the integration of Darwin’s theory with genetics, in the early 20th century, gave rise to neo-Darwinism; and why, despite evolutionary theory being a mainstay of modern biology, in society at large there is a marked reluctance to believe in evolution.

Natural selection and adaptation

2018 ◽  
Author(s):  
Tim Lewens
Keyword(s):  
Natural Selection ◽  
Functional Traits ◽  
Evolutionary Biology ◽  
Skin Pigmentation ◽  
Essential Element ◽  
Natural World ◽  
Modern Biology ◽  
Biology Textbook ◽  
Selection For ◽  
The Relationship

Students of the natural world have long remarked on the fact that animals and plants are well suited to the demands of their environments. ‘Adaptation’, as it is used in modern biology, can name both the process by which organisms acquire this functional match, and the products of that process. Eyes, wings, beaks, camouflaging skin pigmentation and so forth, are all ‘adaptations’ in this second sense. Modern biological orthodoxy follows Darwin in giving a central role to natural selection in explaining the production of adaptations such as these. This much is uncontroversial. But a number of more contentious conceptual questions are raised when we look in more detail at the relationship between natural selection and adaptation. One of these questions concerns how we should define adaptation. It is tempting to characterize adaptations as functional traits – eyes are for seeing, large beaks are for cracking tough seed-casings. This in turn has led many commentators in biology and philosophy to define adaptations as those traits which have been shaped by natural selection for their respective tasks. Others – especially biologists – have complained that such a definition trivializes Darwin’s claim that natural selection explains adaptation. This claim was meant to be an important discovery, not a definitional consequence of the meaning of ‘adaptation’. These worries naturally lead on to the issues of how natural selection itself is to be understood, how it is meant to explain adaptation, and how it should be distinguished from other important evolutionary processes. These topics have a historical dimension: is Darwin’s understanding of natural selection, and its relationship to adaptation, the same as that of today’s evolutionary biology? Textbook presentations often say yes, and this is surely legitimate if we make the comparison in broad terms. But differences emerge when we look in more detail. Darwin, for example, seems to make the ‘struggle for existence’ an essential element of natural selection. It is not clear whether this is the case in modern presentations. And Darwin’s presentation is largely neutral on the inheritance mechanism that accounts for parent/offspring resemblance, while modern presentations sometimes insist that natural selection always implies a genetic underpinning to inheritance.

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