Hello again,
Another question regarding carotenoids... (by the way thanks a lot Dr.
Leray, both for your excellent and comprehensive website and also for
this discussion group).
I've seen in a paper that Kow values (octanol-water partitioning
coeficient) were given for carotenoids (and lipid soluble vitamins) in
the range of 12-14 (values estimated from the model KOWWIN developped
by Syracuse university, NY). Is it a common practice in lipid sciences
to express the hydrophobicity of a compound using Kow values?
I am wondering at first because I am an environmental scientist and we
use this chemodynamic value to express the behaviour of an
anthropogenic contaminant such as PCBs, PAHs... also because as far
as I know a Kow value of more than 8-9 is out of the "experimental
scale"...
Thanks
Maxime
Dear all
Appologies as this may be a stupid question, but is it possible to
perform a fatty acid analysis on perfused tissues? We perfuse with 4%
paraformaldehyde, does anyone know what this does to the lipids?
Many Thanks
Simon Dyall
Dear Dr.Claude
wat `s the purpose of using the ratio 2:1 with
benzene:methanol or 2:1 with hexane:methanol in the extraction of pigments from
leaf .PLZZ EXPLAIN? and why 100% acetone alone used in pigement extraction?
IF CHLOROPHYLL A & B SOLUBLE IN BOTH POLAR N NONPOLAR SOLVENTS
WHICH`S THE BEST PROCEDURE OF UNDESTRUCTIVE EXTRACTION
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Hello
The best way to isolate xanthophylls and chlorophylls
from a lipid mixture is to use a liquid partition as
dsecribed by Minguez-Mosquera for oils (J Am Oil Chem
Soc 1990, 67, 192-6). The technique is based on the
selective partition of components between
dimethylformamide and hexane. The hexane phase
concentrates lipids and carotene while
dimethylformamide phase retains chlorophylls and
xanthophylls. All analyses must be performed under
green light.
Dr Claude Leray
___________________________________________________________________________
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Hie, bonjour
I'd like to know if anyone has suggestions on how to seperate
xanthophyll carotenoids (and their respective esters) from a lipid
matrix.
I am analyzing carotenoids in fat-rich fish tisues and mussells but I
suspect my analytical column (C8-HPLC) to be saturated with lipids.
Any help would be appreciated.
Thanks
I suggest you to apply the extraction recipe adapted
for bacteria and described in the following paper :
Lewis T et al., J Microbiol meth 2000, 43, 107-116.
According to that work, you may also determine the
total FA content but if you want to separate lipid
classes, you may follow one of the efficient
procedures described in my web site
(www.cyberlipid.org). Thus, you are sure to obtain
good results with excellent recoveries.
Best regards
Dr Claude Leray
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Hi,
thanks for replying.
The lipids are taken from Mycobacterium bovis cells
http://en.wikipedia.org/wiki/Mycobacterium_bovis
Non-polar lipids that we want to study include the
triacylglycerides, any non-polar lipids that we can possibly
extract, and Vitamin K2 which is non-polar as well.
Thank you for your time.
regards,
wk
--- In lipids@..., Claude Leray <clleray@y...> wrote:
> To give you some suggestions it's necessary to know
> the nature of the samples you analyze and the
> non-polar lipids you want to study.
> Leray Claude
To give you some suggestions it's necessary to know
the nature of the samples you analyze and the
non-polar lipids you want to study.
Leray Claude
___________________________________________________________________________
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Hi,
I am experiencing some difficulty in extracting non-polar lipids. I
was wondering if any one out there knows of any protocols (in websites
or journal articles) which details the steps involved.
regards,
wk
Dear Lipid Fraternity,
I am working with a oil processing company in India
We have options with us to use either "Solvent Extracted Sunflower
oil "or "Crude Expeller Oil" for Refining .
May I request our friends to give their valuable opinion about shelf
life of Refined oil produced from Solvent extracted seed oil.
Is using solvent extracted oil in place of Expeller based oil for
refining has got any bad effect on quality of refined oil in due
course?
I would be grateful for your suggestions.
Anticipating early responses!
best regards
Pankaj Verma
Hello,
I can give you the Rf values I had with the first
solvent system according to the Heape's method with a
7.5 cm running distance on HPTLC plates :
PE: 0.56, PI: 0.39, PS: 0.27, SM: 0.07, PA: 0.49, CL:
0.45, PG: 0.53
It must be noticed that these values are not
definitive because of the variability of the
separation parameters.
Leray Claude
--- gonzalo obal <gonchi3001@...> a écrit :
>
> Hi, everyone.
>
> I´m looking for Rf values of lipid classes separated
> by HPTLC using silica gel plates using two
> solvent-step:
> Fist for PL:
> Methylacetate/isopropanol/chloroform/methanol/KCl
> (0.25%) (25:25:25:10:9 v/v).
> And then for NL:
> Hexane/diethyleter/acetic acid (80:20:1) (v/v).
> Has anyone this information? Thanks in advance.
>
>
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Hi, everyone.
I´m looking for Rf values of lipid classes separated
by HPTLC using silica gel plates using two
solvent-step:
Fist for PL:
Methylacetate/isopropanol/chloroform/methanol/KCl
(0.25%) (25:25:25:10:9 v/v).
And then for NL:
Hexane/diethyleter/acetic acid (80:20:1) (v/v).
Has anyone this information? Thanks in advance.
_________________________________________________________
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Hello everybody,
I am not very confident with the furtherance of previous contacts I
have made with lipid specialists... this site might then be very
useful to solve my problem.
I work in a lab dedicated to cell biology and we are far more
comfortable with proteins there than with lipids there.
It turns out that we have produced monoclonal antibodies able to
interfere with binding of (what looks very much like a) GSL at the
surface of embryonic stem cells with a (yet to be identified)
membrane receptor present at the surface of cells of a feeder layer.
Co-cultures always result in cell cycle exit for the ES cells unless
one of our monoclonal is included before, during or long after co-
culture onset. We are then very excited about identifying this
receptor/ligand system able to command proliferation or cell cycle
arrest at will.
Despite proficient technical information available from Dr C. Leray's
web site:
www.cyberlipid.com
and as we are a small group with lots of things to do, we think it is
more efficient to collaborate with specialists than to try to become
one! For this reason, we are now seeking a laboratory willing to
collaborate with us in the formal identification of "our" GSL. To
this end we would of course provide all necessary reagents as well as
manpower on site in order to achieve rapid identification by means of
HPTLC-immunostaining based techniques.
On another hand, should the work require mass cell culture, solvent
extractions and large scale preparative chromatographies we would
obviously have to discuss further the terms of said collaboration.
We are looking eagerly forward to hearing from you
Thanks for this nice forum
Jopadove et al.
Dear Sir,
Thank you for your prompt response. We have prepared sustained release matrices
of using gelucire by melt solidification. But on ageing we find enhace ageing.
It may be due to convergion of triglycerides (gelucire) to more stable polymorph
of gelucire. We have confirmed these changes by Hotstagepolarizing microscopy,
Differential Scanning calorimetery etc. In this study we observed that
crystallinity increases during ageing. When we add the glyceryl monosteates
(different grades) than we observed that GMS having higher m.p. causes faster
crystallization as compared to GMS having lower m.p. which causes slower
crystallization (confirmed by DSC). Our hypothesis is that gelucire convert into
more stable polymorph rapidly deu to faster crystallization as compred to slower
crystallizations. In the first case we are able to stabilized the release
changes as compared to faster crystallization. We dont know whether we are
correct or not. Thats why we are searching any refernces regarding
the use of Nucleation enhancers in case of lipid or fat systems.
I will be highly thankfull to you if you kindly provide the xerox copy of the
Ueno, and SATO publications and a chapter of Sato book. We will acknowledge your
support in our dessertation work. We want to read in detail before we conclude
any thing.
I would like to know your affiliation and your working area.
Regards,
Bhaskar Chauhan
Bhaskar Chauhan
Senior Research Fellow,
Dept. of Pharmaceutics,
Poona College of Pharmacy,
Erandwane,
Pune-411038
Mobile no: +91 9822290326
Phone no: 91 20 5437237
Fax no: 91 20 5439383
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You kan also look into the publications of Ueno, and SATO, ...yes We
have the book ;-)
Do you think you got the problem right... if you enhance the forgoing of
the crystallization you will release faster...
I don' know wether I got you right
Cheers Daniel
>
>I am working as a senior reserach fellow in Bharati vidyapeeth, Department of
Pharmaceutics, Poona College of Pharmacy, India. At present i am working on
lipid based formulations on oral administrations of drugs using specially
misture og triglycerides lipid with fatty acid ester. But on storage of theses
formulations the reslease properties of theses enhaces. I have read it in a US
patent by adding some nucleation enhacers (for example glyceryl monostearates)
these changes can be prevented. If any body have more information use of
nucleation enhancer (Any reference, mechanism of action etc) please let me
inform me. Please also let me know that if any body have a book titled "
Crystallization and polymorphism of fats and lipid" by Garti and Sato.
>
>
________________________________________________
Daniel KALNIN ,
UMR CNRS 8612
Equipe Physicochimie des Systemes Polyphases
Université Paris Sud
5, rue J-B Clement, 92296, CHATENAY-MALABRY
FRANCE
mailto:daniel.kalnin@...
Tel: +33 01 46 83 54 65
cell: +33 06 30 07 07 38
Fax: +33 01 46 83 53 12
icq: 105146572
________________________________________________
Dear Friends,
I am working as a senior reserach fellow in Bharati vidyapeeth, Department of
Pharmaceutics, Poona College of Pharmacy, India. At present i am working on
lipid based formulations on oral administrations of drugs using specially
misture og triglycerides lipid with fatty acid ester. But on storage of theses
formulations the reslease properties of theses enhaces. I have read it in a US
patent by adding some nucleation enhacers (for example glyceryl monostearates)
these changes can be prevented. If any body have more information use of
nucleation enhancer (Any reference, mechanism of action etc) please let me
inform me. Please also let me know that if any body have a book titled "
Crystallization and polymorphism of fats and lipid" by Garti and Sato.
Awaiting for your reply,
Regards,
Bhaskar Chauhan
Bhaskar Chauhan
Senior Research Fellow,
Dept. of Pharmaceutics,
Poona College of Pharmacy,
Erandwane,
Pune-411038
Mobile no: +91 9822290326
Phone no: 91 20 5437237
Fax no: 91 20 5439383
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I request UV-IRS spectrum of liposoms.
Thanks, Mayra
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Dear Williams,
it is a difficult task to give you answers to your
general questions.
For lipid analysis and extraction, you may visit my
web site : www.cyberlipid.org
to find several ways of approach to your analytical
problems.
For terpenes, it is more difficult becausse of the
variety of molecules but you may find help in browsing
internet with the help of google. I tried with
terpenes and extraction or analysis, and I got a lot
of interesting responses.
For polyphenols the best is to read some books devoted
to these compounds and after, to collect more
specialised papers.
I give you below some of them:
Analysis of phenolic plant metabolites, Waterman PG
and Mole S, Blackwell sci Public.
Techniques of flavonoid identification, Markham KR,
Academic Press 1982
Methods in polyphenol chemistry, Pridham JB, Pergamon
Press, 1963
Among sci journals:
Adamson GE et al., J Agric Food Chem 1999, 47, 4184
Lazarus SA et al., J Agric Food Chem 1999, 47, 3693
Sun B et al., J Agric Food Chem 1998, 46, 1390
Arts CW et al., J Agric Food Chem 1998, 46, 5156
Merken HM et al., J Agric Food Chem 2000, 48, 577
Amakura Y et al., J Chromatogr A, 2000, 891, 183
Regards
Leray Claude
http://www.cyberlipid.org
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dear sir ,
I would like to know more about the aim of your
present study.µ
This experience is easy to realise it but you must be
more pricize and consize
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dear sir,
i`ve just started research on plant phytochemical
extraction.please suggest some websites /books/articles related to
simple extraction procedures of
alkaloids/terpenes/sterols/lipids/flavanoids/lignins/tannins/polypheno
ls,quantitative tests for precise detection of each compound in
plants.
thanku....
waiting for an early reply
scottwilliams
Dear Simon,
Clearly it is impossible to separate individual
phospholipids on SPE columns. For that purpose, you
need very long columns, very little bed particles and
gradient elution. Thus, these conditions are those of
HPLC. You will find examples of phospholipid
separation on the following site:
http://www.cyberlipid.org
Best regards
Leray Claude
___________________________________________________________
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Dear all
I want to separate phospholipids by solid phase extraction on
aminopropyl columns. Does anyone know of a method for isolating the
extract into the individual classes, LPC, PC, PE, PI, PS and SPH? At
the moment I am eluting the neutral PLs in MeOH, as Kaluzny et al.
1985, and separating these by thin-layer chromatography. I was
hoping to separate PI and PS on the column using different acid
concentrations, does anyone know their pKas?
Many thanks for any information given.
Regards
Simon Dyall
Dear Babu,
You will be probably disappointed but there are no
special lipids in mammals. Except some exotic
molecules, one finds in this group all lipids that
were described in all animals and even in plants.
There is a common catalogue for all living species and
a great effort is necessary to identify lipid
molecules specific to some rare species. If you are
doubtfull, have a look to www.cyberlipid.org
Regards
Leray Claude
http://www.cyberlipid.org
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Dear Lipid fans,
I am trying to catalogue all lipids in the mammalian (specifically
human) species. Are there similar or related databases available out
there. Any help on this is greatly appreciated.
Thanks in advance
--Babu
hi..
Can any one please suggest a protocol for fluorescent labeling of
small molecules ... especially molecules having amino groups with
thicyanate fluorescent labels... and how to separate teh reactans
from the product finally.. thank you very much...more specificaly
rhodamine labeling of primary amines...
PS: i dont want protocols for protein labeling..
thanks in advance..
As you need unsaturated phospholipids for your
experiments, the best way is to prepare them from
animals previously injected with radioactive
precursors. As an example, you may read the ancient
paper by Zborovsky et al., (Biochim Biophys Acta 1977,
497, 183) and the book of Bergelson (Lipid biochemical
preparations, Elsevier 1980) concerning the
preparation of phosphatidylcholine from rats injected
with C14 labelled choline chloride. This approach
which is the cheapest may be extended to any
phospholipid group.
Leray Claude
http://www.cyberlipid.org
___________________________________________________________
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We are interested in determining the capacity of
oxidised phospholipids to bind to proteins. For that
purpose we would like to label these phospholipids,
but we are not able to carry out it biosynthetically.
Is there any method for this purpose? Thanks in advance,Gonchi
_________________________________________________________
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We are interested in determining the capacity of oxidised
phospholipids to bind to proteins. For that purpose we would like to
label these phospholipids, but we are not able to carry out it
biosynthetically. Is there any method for this purpose?
Thanks in advance,
Gonchi
Forwarded from Plant Lipids NPLC-L (see links at end)
Two postdoctoral positions are available for an NSF-Plant Genome
Research Program funded project on the proteomics of seed development
in oilseeds. The overall goal of this project is to profile the
dynamics of protein expression and modification during key stages of
seed-filling in model and crop oilseeds. Advanced instrumentation
for protein separation and identification will be employed for high-
throughput protein profiling. Funding for this project is renewable
for a period of four years and coincides with development of the MU
Proteomics Center (www.proteomics.missouri.edu). A newly released,
liquid chromatography-linear ion trap tandem mass spectrometer
platform will be purchased with funds from this grant and will be
used exclusively for the proposed research. Training will be
provided for the use of this state-of-the-art mass spectrometer.
Prior experience in any of the following areas: protein biochemistry
including 2-D electrophoresis, mass spectrometry and bioinformatics
is desirable. Applicants should possess a Ph.D. degree in
Biochemistry, Biology, Molecular Biology or Bioinformatics and have a
strong interest in seed metabolism. Excellent oral and written
communication skills and the ability to work well in a collaborative
research environment are essential. Competitive salary (commensurate
with experience), fringe benefits including health insurance, and
travel support to meetings are available for these positions. Please
Email curriculum vitae including names of three references and a
cover letter describing research experience and professional goals
to: Dr. Jay Thelen (thelenj@...), Division of Biological
Sciences, 125 Chemistry, University of Missouri-Columbia, Columbia MO
65211
National Plant Lipid Mailing List
http://www.msu.edu/~ohlrogge/subscribe.html
Plant Lipids Homepage
http://trevor.butler.edu/~kschmid/lipids.html
National Plant Lipids Cooperative
http://www.plantlipids.org/
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