scholarly journals Odour character differences for enantiomers correlate with molecular flexibility

2008 ◽  
Vol 6 (30) ◽  
pp. 75-86 ◽  
Author(s):  
Jennifer C Brookes ◽  
A.P Horsfield ◽  
A.M Stoneham
Keyword(s):  
Small Molecules ◽  
Olfactory System ◽  
Membered Ring ◽  
Structural Flexibility ◽  
Important Class ◽  
Separate Factor ◽  
Extensive Class ◽  
Left And Right ◽  
The Brain ◽  
Card Model

The olfactory system sensitively discerns scents from many small molecules as the brain analyses signals from nasal receptors. These receptors are selective to some degree, though the mechanism for selectivity is still controversial. Enantiomers, chiral pairs of left- and right-handed structures, are an important class of molecules in assessing proposed mechanisms. We show that there is a correlation between molecular (structural) flexibility and whether or not the left- and right-handed enantiomers smell the same. In particular, for the fairly extensive class of enantiomers with six-membered ring flexibility, enantiomers do not smell the same. There are, of course, significant experimental uncertainties, which we discuss here. We discuss models of receptor selectivity, both those based on shape and those where discrimination is based on other factors, such as electron affinity, proton affinity or vibration frequencies. The differences in scent of these enantiomers appear to be consistent with simple generalizations of a ‘swipe card’ model in which, while the shape must be good enough, critical information for actuation is a separate factor.

The Rise of Endothermy

2019 ◽  
pp. 337-422
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
Cerebellar Cortex ◽  
Mass Extinction ◽  
Olfactory System ◽  
Convergent Evolution ◽  
Brain Size ◽  
Reciprocal Connections ◽  
Left And Right ◽  
Excellent Color ◽  
The Brain ◽  
Commissural Connections

Mammals and birds exhibit many examples of convergent evolution, including endothermy and related traits that helped them survive the end-Cretaceous mass extinction. The subsequent diversification of both lineages was accompanied by multiple expansions in relative and (often) absolute brain size. Examples of convergent evolution in the brain include complex folding of the cerebellar cortex, complex auditory circuits, and highly laminar areas within the telencephalon. Of course, birds and mammals also diverged in numerous respects. In particular, early mammals (but not birds!) shifted into a nocturnal niche, which was accompanied by an expansion of the olfactory system and the evolution of highly light-sensitive eyes. In the process, early mammals became “color-blind,” but excellent color vision re-evolved in some diurnal lineages, notably platyrrhine primates. Mammalian brains are also unusual for having strong reciprocal connections between thalamus and dorsal pallium (i.e., neocortex) and extensive commissural connections between the left and right neocortex.

Advantages of Complementary Stereo Images as Viewed with the Low-Temperature Field-Emission SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1314-1315
Author(s):  
William P. Wergin ◽  
Eric F. Erbe
Keyword(s):  
Fold Increase ◽  
Horizontal Displacement ◽  
Three Dimensions ◽  
Stereo Image ◽  
Stereo Pair ◽  
Sem Micrograph ◽  
Left And Right ◽  
The Common ◽  
The Brain ◽  
Pair Analysis

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.

scholarly journals The Hammer and the Nail: Biomechanics of Striking and Struck Canadian University Football Players

2021 ◽  
Author(s):  
Jeffrey S. Brooks ◽  
Adam Redgrift ◽  
Allen A. Champagne ◽  
James P. Dickey
Keyword(s):  
College Football ◽  
Head Impact ◽  
Football Players ◽  
Video Footage ◽  
Impact Location ◽  
Rule Changes ◽  
Left And Right ◽  
The Brain

AbstractThis study sought to evaluate head accelerations in both players involved in a football collision. Players on two opposing Canadian university teams were equipped with helmet mounted sensors during one game per season, for two consecutive seasons. A total of 276 collisions between 58 instrumented players were identified via video and cross-referenced with sensor timestamps. Player involvement (striking and struck), impact type (block or tackle), head impact location (front, back, left and right), and play type were recorded from video footage. While struck players did not experience significantly different linear or rotational accelerations between any play types, striking players had the highest linear and rotational head accelerations during kickoff plays (p ≤ .03). Striking players also experienced greater linear and rotational head accelerations than struck players during kickoff plays (p = .001). However, struck players experienced greater linear and rotational accelerations than striking players during kick return plays (p ≤ .008). Other studies have established that the more severe the head impact, the greater risk for injury to the brain. This paper’s results highlight that kickoff play rule changes, as implemented in American college football, would decrease head impact exposure of Canadian university football athletes and make the game safer.

The brain of the tree pangolin (Manis tricuspis ). II. The olfactory system

2018 ◽  
Vol 526 (16) ◽  
pp. 2548-2569 ◽  
Author(s):  
Aminu Imam ◽  
Adhil Bhagwandin ◽  
Moyosore S. Ajao ◽  
Muhammed A. Spocter ◽  
Amadi O. Ihunwo ◽  
...  
Keyword(s):  
Olfactory System ◽  
The Brain

scholarly journals Modulation of PKM activity affects the differentiation of TH17 cells

2020 ◽  
Vol 13 (655) ◽  
pp. eaay9217
Author(s):  
Scott M. Seki ◽  
Kacper Posyniak ◽  
Rebecca McCloud ◽  
Dorian A. Rosen ◽  
Anthony Fernández-Castañeda ◽  
...  
Keyword(s):  
T Cell ◽  
Small Molecules ◽  
Th17 Cells ◽  
Cell Function ◽  
Therapeutic Potential ◽  
Interleukin 17 ◽  
Gm Csf ◽  
T Cell Function ◽  
The Brain ◽  
Tgf Β1

Small molecules that promote the metabolic activity of the pyruvate kinase isoform PKM2, such as TEPP-46 and DASA-58, limit tumorigenesis and inflammation. To understand how these compounds alter T cell function, we assessed their therapeutic activity in a mouse model of T cell–mediated autoimmunity that mimics multiple sclerosis (MS). TH17 cells are believed to orchestrate MS pathology, in part, through the production of two proinflammatory cytokines: interleukin-17 (IL-17) and GM-CSF. We found that both TEPP-46 and DASA-58 suppressed the development of IL-17–producing TH17 cells but increased the generation of those producing GM-CSF. This switch redirected disease pathology from the spinal cord to the brain. In addition, we found that activation of PKM2 interfered with TGF-β1 signaling, which is necessary for the development of TH17 and regulatory T cells. Collectively, our data clarify the therapeutic potential of PKM2 activators in MS-like disease and how these agents alter T cell function.

scholarly journals The cell biology of smell

2010 ◽  
Vol 191 (3) ◽  
pp. 443-452 ◽  
Author(s):  
Shannon DeMaria ◽  
John Ngai
Keyword(s):  
Olfactory System ◽  
Cell Biology ◽  
Odorant Receptor ◽  
Large Family ◽  
G Protein Coupled Receptors ◽  
Odorant Receptors ◽  
Chemical Structures ◽  
Wide Range ◽  
G Protein Coupled ◽  
The Brain

The olfactory system detects and discriminates myriad chemical structures across a wide range of concentrations. To meet this task, the system utilizes a large family of G protein–coupled receptors—the odorant receptors—which are the chemical sensors underlying the perception of smell. Interestingly, the odorant receptors are also involved in a number of developmental decisions, including the regulation of their own expression and the patterning of the olfactory sensory neurons' synaptic connections in the brain. This review will focus on the diverse roles of the odorant receptor in the function and development of the olfactory system.

Carnosine in the brain and olfactory system of amphibia and reptilia: A comparative study using immunocytochemical and biochemical methods

1991 ◽  
Vol 130 (2) ◽  
pp. 182-186 ◽  
Author(s):  
Cristina Artero ◽  
Elisa Martì ◽  
Stefano Biffo ◽  
Bruno Mulatero ◽  
Claudia Andreone ◽  
...  
Keyword(s):  
Comparative Study ◽  
Olfactory System ◽  
Biochemical Methods ◽  
The Brain

scholarly journals Heparin Binding Proteins as Therapeutic Target: An Historical Account and Current Trends

Medicines ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 80 ◽  
Author(s):  
Giancarlo Ghiselli
Keyword(s):  
Small Molecules ◽  
Biological Function ◽  
Antithrombin Iii ◽  
Biological Effects ◽  
Structural Flexibility ◽  
Heparin Binding ◽  
New Class ◽  
High Affinity ◽  
Current Trends ◽  
High Degree

The polyanionic nature and the ability to interact with proteins with different affinities are properties of sulfated glycosaminoglycans (GAGs) that determine their biological function. In designing drugs affecting the interaction of proteins with GAGs the challenge has been to generate agents with high binding specificity. The example to emulated has been a heparin-derived pentasaccharide that binds to antithrombin-III with high affinity. However, the portability of this model to other biological situations is questioned on several accounts. Because of their structural flexibility, oligosaccharides with different sulfation and uronic acid conformation can display the same binding proficiency to different proteins and produce comparable biological effects. This circumstance represents a formidable obstacle to the design of drugs based on the heparin scaffold. The conceptual framework discussed in this article is that through a direct intervention on the heparin-binding functionality of proteins is possible to achieve a high degree of action specificity. This objective is currently pursued through two strategies. The first makes use of small molecules for which in the text we provide examples from past and present literature concerning angiogenic factors and enzymes. The second approach entails the mutagenesis of the GAG-binding site of proteins as a means to generate a new class of biologics of therapeutic interest.

Age and sex specific brain biometrical study in Vanaraja chickens

2017 ◽  
Author(s):  
Kuldeep Kumar Panigrahy ◽  
Kumaresh Behera ◽  
Lal Mohan Mohapatra ◽  
Arun Kumar Mandal ◽  
Kamdev Sethy ◽  
...  
Keyword(s):  
Brain Volume ◽  
Cerebral Hemispheres ◽  
Male And Female ◽  
Cervical Dislocation ◽  
Left And Right ◽  
The Mean ◽  
The Brain ◽  
Biometrical Study ◽  
Age And Sex

The objective of this study was to evaluate the brain biometrical dynamics with advancement of age between sexes. One hundred fifty day-old sexed Vanaraja chicks (75 male + 75 female) were selected and distributed equally in two groups. Birds were slaughtered by cervical dislocation method at 21, 42, 63 and 84 days of age and biometrical measurements were taken. From our present study we observed brain volume had shown significant (P>0.05) changes with respect to age and sex of birds. The mean length of both left and right cerebral hemispheres between male and female birds had varied significantly (P>0.05). With advancement of age, hemispheric length varied significantly (P>0.05). The major finding was that cerebral width significantly (P>0.05) increased from 42-63 days of age and in male birds cerebellar length increased from 63 days onwards. There were age-specific changes in all the morphometrical parameters where as between sexes there were some minor variations.

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