283 research outputs found
The Isolation and Study of Some Naturally Occurring Fluorescent Organic Compounds and Stereoisomerization of Prolycopene, Pro-γ-Carotene, and Lycopene in Chickens and Hens
A report on the detection, analysis, spectrum, and identification
of several polycyclic aromatic hydrocarbons as lipoid-soluble,
fluorescent organic compounds occurring in certain marine invertebrates
(barnacles) is presented. Crystalline preparations of these compounds
have been obtained from the intensely fluorescent zones resulting
from chromatographic resolution of the crude barnacle extracts. These
hydrocarbons include anthracene, phenanthrene, fluoranthene, chrysene,
1,12-benzperylene, coronene, and the strongly active carcinogen,
3,4-benzpyrene. Similar experiments carried out with the beach worm have
revealed only traces of polycyclic aromatic compounds. They have not
been found in deep-sea mud samples or in some seaweeds tested. Some
suggestions are made as to the origin of these compounds in barnacles
(and beach worms).
When polycis carotenoids are fed to chickens and hens over a
period of several days, and the crude extracts of the different
tissues, gut washings, and feces of these animals are submitted to
chromatographic analysis, the pigments recovered are found to consist
of the unchanged starting compound and stereoisomerized forms.
This bio-stereoisomerization results in the formation of not only
the all-trans and neo-forms of the carotenoid administered but also
polycis isomers, some of which possess more cis double bonds than
the starting material.</p
Chiral molecule adsorption on helical polymers
We present a lattice model for helicity induction on an optically inactive
polymer due to the adsorption of exogenous chiral amine molecules. The system
is mapped onto a one-dimensional Ising model characterized by an on-site
polymer helicity variable and an amine occupancy one. The equilibrium
properties are analyzed at the limit of strong coupling between helicity
induction and amine adsorption and that of non-interacting adsorbant molecules.
We discuss our results in view of recent experimental results
Conceptual design of a two stage to orbit spacecraft
This project, undertaken through the Advanced Space Design Program, developed a 'Conceptual Design of a Two Stage To Orbit Spacecraft (TSTO).' The design developed utilizes a combination of air breathing and rocket propulsion systems and is fully reusable, with horizontal takeoff and landing capability. The orbiter is carried in an aerodynamically designed bay in the aft section of the booster vehicle to the staging altitude. This TSTO Spacecraft design meets the requirements of replacing the aging Space Shuttle system with a more easily maintained vehicle with more flexible mission capability
Preparation of amino-substituted indenes and 1,4-dihydronaphthalenes using a one-pot multireaction approach: total synthesis of oxybenzo[c]phenanthridine alkaloids
Allylic trichloroacetimidates bearing a 2-vinyl or 2-allylaryl group have been designed as substrates for a one-pot, two-step multi-bond-forming process leading to the general preparation of aminoindenes and amino-substituted 1,4-dihydronaphthalenes. The synthetic utility of the privileged structures formed from this one-pot process was demonstrated with the total synthesis of four oxybenzo[c]phenanthridine alkaloids, oxychelerythrine, oxysanguinarine, oxynitidine, and oxyavicine. An intramolecular biaryl Heck coupling reaction, catalyzed using the Hermann–Beller palladacycle was used to effect the key step during the synthesis of the natural products
A complex interaction between glycine/NMDA receptors and serotonergic/noradrenergic antidepressants in the forced swim test in mice
Both clinical and preclinical studies demonstrate the antidepressant activity of the functional NMDA receptor antagonists. In this study, we assessed the effects of two glycine/NMDA receptor ligands, namely L-701,324 (antagonist) and d-cycloserine (a partial agonist) on the action of antidepressant drugs with different pharmacological profiles in the forced swim test in mice. Swim sessions were conducted by placing mice individually in glass cylinders filled with warmed water for 6 min. The duration of behavioral immobility during the last 4 min of the test was evaluated. The locomotor activity of mice was measured with photoresistor actimeters. L-701,324 and d-cycloserine given with reboxetine (administered in subeffective doses) did not change the behavior of animals in the forced swim test. A potentiating effect was seen when both tested glycine site ligands were given concomitantly with imipramine or fluoxetine in this test. The lesion of noradrenaline nerve terminals produced by DSP-4 neither altered the baseline activity nor influenced the antidepressant-like action of L-701,324 or d-cycloserine. The depletion of serotonin by p-CPA did not alter baseline activity in the forced swim test. However, it completely antagonized the antidepressant-like action produced by L-701,324 and d-cycloserine. Moreover, the antidepressant-like effects of imipramine, fluoxetine and reboxetine were abolished by d-serine, a full agonist of glycine/NMDA receptors. The present study demonstrates that glycine/NMDA receptor functional antagonists enhance the antidepressant-like action of serotonin, but not noradrenaline-based antidepressants and such their activity seems to depend on serotonin rather than noradrenaline pathway
Proteomics of Buccal Cavity Mucus in Female Tilapia Fish (Oreochromis spp.): A Comparison between Parental and Non-Parental Fish
Mouthbrooding is an elaborate form of parental care displayed by many teleost
species. While the direct benefits of mouthbrooding such as protection and
transportation of offsprings are known, it is unclear if mouthbrooding offers
additional benefits to embryos during incubation. In addition, mouthbrooding
could incur negative costs on parental fish, due to limited feeding
opportunities. Parental tilapia fish (Oreochromis spp.) display
an elaborated form of parental care by incubating newly hatched embryos in oral
buccal cavity until the complete adsorption of yolk sac. In order to understand
the functional aspects of mouthbrooding, we undertake a proteomics approach to
compare oral mucus sampled from mouthbrooders and non-mouthbrooders,
respectively. Majority of the identified proteins have also been previously
identified in other biological fluids or mucus-rich organs in different
organisms. We also showed the upregulation of 22 proteins and down regulation of
3 proteins in mucus collected from mouthbrooders. Anterior gradient protein,
hemoglobin beta-A chain and alpha-2 globin levels were lower in mouthbrooder
samples. Mouthbrooder oral mucus collectively showed increase levels of proteins
related to cytoskeletal properties, glycolytic pathway and mediation of
oxidative stress. Overall the findings suggest cellular stress response,
probably to support production of mucus during mouthbrooding phase
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