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Date:         Thu, 4 Dec 2003 08:24:24 +0100
Reply-To: "Rodolfo Nicolaus (by way of Claudio Della Volpe)" <rnicolaus@TIGHTROPE.IT>
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From: "Rodolfo Nicolaus (by way of Claudio Della Volpe)" <rnicolaus@TIGHTROPE.IT>
Subject:      SCI-list avvisi: recent advancements in black pigments
To: SCI-LIST@LIST.CINECA.IT

Questo messaggio vi giunge dalla Lista di Posta elettronica della Societa' Chimica Italiana, cui risultate iscritti; la lista di posta "SCI-list avvisi" e' dedicata alla spedizione di messaggi ufficiali della SCI e delle sue divisioni o ad avvisi di congressi, seminari, etc.; e' aperta ai soli soci.
Per ulteriori informazioni collegatevi alla pagina: http://sci-list.ing.unitn.it.
 

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Pagina di testo corrispondente all'indirizzo di Rodolfo Nicolaus.
 
 
 

With the author's compliments

Rodolfo Alessandro Nicolaus. Chemist
born
August 1, 1920 in Naples off Mustair parents. Pupil of M. Bakunin
(Naples), T.Reichstein (Basle), L. Panizzi (Rome). Research  on
Archaebacteria from Campi Flegrei-volcanos started at the Laboratorio
per la Chimica e Fisica delle Molecole di Interesse Biologico (Arco
Felice CNR, Rome,  1968-1975)  . bnicolaus@icmib.na.cnr.it .
Centrospermae pigments were discovered, mario.piattelli@poste.it  at
the Organic Chemistry Institute of Naples University. The beginn of
marine products chemistry occurs in the same period.  fattoru@unina.it
Following earlier reearch (1949-1975) papers on chemistry and physics
of black particles are published (1995-2003 )
 

              The road to knowledge is full of obstacles the main
one  being not to admit  his own  ignoranceÖ.(anonymous of the
fourteenth century )
 

 
Melanin studies: introduction. (1995-2003
After the Ghent Conference September 2003
 

 Black pigments  are amorphous semicoductors  mostly after
doping.Threshold switching was observed
(www.organicsemiconductors.com  ). Black materials are generally
amorphous semiconductors but the conducting and superconducting
fulvalenes ( EDOEDTTTF, EDOMDTTTF, EDOVDTTTF, MDTTTF ) complex salts
are known to form beautiful black crystals.
  '' Colour ''  depends not only on the gap (expressed in eV ) of the
semiconductor model  but also by particle structure which could
explain why the methyl ether is not  black anymore.Melanin is also
responsible for blue or green colours in  animal kingdom.

In nature the black particles ( BCM = black cell matter, melanin ,
natural melanins , eumelanins etc  )  may  form from cyclodopa ,
serotonine, catecholamines, dihydroxytryptamines,   dopa,  dopamine,
adrenaline, dihydroxyquinolines or in general from polyphenols  An
attempt  to clarify the complex process of  melanogenesis leads to
the scheme known as Raper scheme in honour of the english
physiologist which studied  , in the past half century, the
enzymatic  melanogenesis of  tyrosine The heterogeneous black
material is generally formed by oxidation ( enzymatic or not ) of
o.diphenols resulting in CO2  evolution and H2O2 formation which may
oxidise the pigment formed..The elemental analysis of the black
material show in general one oxygen more than the precursor.This may
be explained with storage of oxygen, water, or addition of water to
the quinone groups, presence of carboxylics  or with a
trihydroxylated-phenyalanine precursor .The precursors can  deeply
change . For example pyrrole rings are present in melanin formed from
indoles..
 Melanins, although impure,  show  typical broad EPR, IR, NMR,
spectra.The spectra may be used for eumelanin identification
comparing it with a know material like  dopa-melanin,
cyclodopa-melanin, DHI-melanin, DHICA-melanin.
 LASER ( MALDI ) is not useful for molecular weight determination
but  operate a fragmentation of the particle. The fragments  can be
used for structural studies of  oligomers,  organelles and particles.
Application in Dermatology and cosmochemistry.
 Methylether are obtained by action of diazomethane on melanins or
pyrrole-black.This could means that hydroxyls are present  or an
unidentified process due to the storage of the gas occurs.
.
It is frequently forgotten that sepiomelanin  ( from the ink sack of
Sepia officinalis )  is the Ca Mg salt of sepiomelanic acid. The
sepiomelanic acid precursor is a carboxylic intermediate of the Raper
scheme. The  black material contained in the ink sack is a  mixture
of  premelanosome,  melanosome , granules and foreign substances not
easy to be  separated as formerly   believed.Furthermore the melanin
is modified by hydrogen peroxide formed during the exatrive process.
In other words the study of melanins have be made on artefacts. High
proportion of degraded DHICA  and DHI or cyclodopa and
decarboxycyclodopa    units was observed in sepiomelanin with
formation of many pyrrole rings  but it is not clear that this is the
result of a  reaction occuring in the cell.   Consequently   melanins
elemental analysis must be considered with criticism.

BSM or black synthetic matter may have  simple precursors like
pyrrole, tiophene,  acetylene, aniline, catecholes, aminocatecholes,
DHI, DHICA, polyphenols,  etc..

 Pheomelanins  ( brown  amorphous animal pigments )  and pheochromes
( yellow,  red, cristallyzable animal pigments  )   are formed from
5-hydroxy-7-alanyl-benzothiazinone ( dibenzothiazinone chromophore )
or  products of tryptophane  metabolism .
 Allomelanins  derive from nitrogen-free precursors ( catecholes,
polyphenols, 1,8-dihydroxynaphtalene etc. ) Typical allomelanins are
pigments from fungi and soil, the most studied    being Aspergillin
and  humic acids.

Melanins  are particles with different shape and size (  also due to
different treatments used and different type of oligomers ) .Melanins
are particles built up  from oligomers ( sometimes degraded
oligomers )  of relative low molecular weight ( 480-1600 ).Oligomers,
the fundamental stones of the particle, are optically active
intermediates. Such oligomers contribute to the shape and size of the
particles and other physical properties. The presence in light
exposed tissues suggest that they are involved in photoreactions
Oligomers are found in nature like the reflecting material of the
tapetum lucidum of the sea catfish.  Melanins might show  various
hydration and oxidation levels.The acetyleneblack radical- polarone
system  is supposed to be contained in all  natural (BCM) and also
in  organic synthetic melanins  (BSM).

Some peculiar properties of black materials are listed below :
  a)   heteogenous amorphous  state of aggregation   b)  electric and
acoustic conductivity, electric switch, photoelectric
conducibility.    c)    binding  power for  organic and inorganic
materials,   ions and molecules  d)  ability of  storing of liquids
and gases  e)  active culture substratum controlling  cell growth and
form.  f)   explosive fragmentation by exposure to LASER beams
(MALDI) . g)   behaviour as innovative sensor and energy generator
with the capacity to grow and shrink significantly in length and
volume when subjected to electric stimulation .h) chemical and
physical data may change with form and size of the particle, methods
of synthesis,   purification and doping.

The above mentioned data strongly suggest melanin being a material of
relevant importance to the  living  matter.
 
 
 
 
 

Author's request
With the aim of establishing a  more fruitful communication, all
visitors are kindly request to specify their scope and interest as
well as their profile and country of location  This request is not
made  for commerciales purposes having the only aim of getting better
acquainted with the counterparts and of improving communication.
R.Nicolaus, Dr. chem.
Rampe Brancaccio 9, I-80132, Napoli.
e-mail: rnicolaus@tightrope.it
http://www.tightrope.it/nicolaus/index.htm
----------------------------------------------------------------------------------------
P.Proctor, J. McGinness
e-mail  :  drp@drproctor.com
www.organicsemiconductors.com
----------------------------------------------------------------------------------------------
 Accademia Pontaniana, Via Mezzocannone 8, I-80134, Napoli.
e-mail: accponta@tin.it      http://www.pontaniana.unina.it
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mario.piattelli@poste.it
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bologne@unina.it

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B.J.R. Nicolaus, Via Crescitelli 6, I-20052 Monza
 bruno.nicolaus@virgilio.it
www.brunonic.org
---------------------------------------------------------------------------------
 
 
 
 
 

melanins  are  also  flyingÖ.
 
 
 
 
 
 
 
 
 
 

STUDIES
(458 pages,Drawing 19, Formulae 172, Pictures 109 ) Home .page..Web.doc

Are referred to different periods of research
 Home Page, Link 1- 4, Link 6, Link 12, Link 15, Link 20-22, are
revised October 2003.
 
 

1.  Colour 70

  2.  Melanin 84

  3.  Colour 90

 4.  Melanin  95-97

5.  Melanins, cosmoids, fullerenes.

  6. On the structure of DHI-melanin

7.  Speculation on the chemistry of interstellar black matter

 8.  The dark secret of life.
 

9. The Nature of Animal Black.

10.  Perspectives in Biology and Melanin Chemistry.
 

11. The nature of Black,Blue, and Green colours in Animals.

12.  DHI-melanin and the melanin in Sepia

13. People of research
      People of BCM and BSM
      Post office
      criticism of literature

14.  Pheomelanin
 

15. Neuromelanin
 

16. 16. Lights in the dark
 

17. Black natural conductors

18. Black Matter: Diffusion

 19. The Pigment Cell and its Biogenesis

20. Raper's scheme

 21. The BCM story

22.  The BCM stories
 
 

Melanins and Black Materials
 

A centre of information and scientific research on colours black
material. This is one of the first scientific  internet centre
granting free  information on the development or state of the art in
the fields supplying data with the only aim of stimulating new
research efforts.   The study is continuosly updated.
Melanin research was started in Naples with a paper on
melanoma-melanin by M.Bakunin(1904).  A paper on sepiomelanin was
published by L.Panizzi  (1952). The early efforts ( 1956-1980 ) were
enabled by the continuous cooperation of valid chemist and biologists
of the Universities of Naples and CNR ( ICMIB), Aberdeen, Newcastle
upon Tyne, Stanford, Manchester.

List of abbreviations :
BCM   =  Black  Cell  Matter  ;  BSM  =  Black  Synthetic Matter  ;
DHI  =  5,6-dihydroxyindole  ;  DHICA  =
5,6-dihydroxyindole-2-carboxylic acid ; Cysdopa  =
cystein-S-yl-dopa  ;  DOPA  =  3,4-dihydroxyphenylalanine  ;  MSH  =
Melanocyte Stimulating Hormone
Key words: melanins, allomelanins, pheomelanins, eumelanins, black
matter, black particles, benzene-black, indole-black, pyrrole-black,
quinoline-black cyclodopa-melanin,  dopa-melanin, DHI-melanin,
melanosome, cosmoids, graphite, fullerenes, amorphous semiconductors,
charge transfer complexes, nanophysics, nanochemistry,
nanobiochemistry, cosmochemistry, MALDI, electroactive polymers, Bok
globules, interstellar matter, X-rays, Mass spectrometry, MALDI-TOF,
EPR  ,NMR ,  band theory, conducting polymers, semiconductors
organic, organic metals, green and blue  colours,  metal porphyrin,
humic acids, PLGA, assembly, trheshold switching, melanin isolation
and purification , quinones hydrate, radical-polarones,  DHI, DHICA,
BCM, BSM, black skin, black feather,black fishes,
meteorites.assembling factor.

This site has been visited   times
© 2003 Tutti i diritti riservati - Page Hosted by Tightrope S.r.l.
last up dating Novenber  2003

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