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Darwin didn't know the mechanism for passing down traits. Mendal predicted a mechanism. The discovery of DNA gave us the actual physical manifestation of it. Science is incremental it doesn't drop from the sky or spout from a burning bush.These laws refuted the idea of passing the acquired traits onto subsequent generations. Not much heard of until the end of the century, Mendel's discovery gained great importance at the beginning of the 1900's. This was the genesis of the science of genetics. Again in the same years, the structure of the genes and the chromosomes was discovered. And in the 1950's, the discovery of the DNA molecule that includes the genetic information put the theory in a great crisis. The reason was the incredible complexity of the DNA, whose origin could never be explained by any random process.
Source[SIZE=-1] Nucleic Acids Research, 2004, Vol. 32, No. 1 127-134
© 2004 Oxford University Press [/SIZE]
Formation of DNA nanoparticles in the presence of novel polyamine analogues: a laser light scattering and atomic force microscopic study
Veena Vijayanathan1, Thresia Thomas2,3,4, Thomas Antony5, Akira Shirahata6 and T. J. Thomas*,1,3 Departments of 1 Medicine, and 2 Environmental and Community Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, 125 Paterson Street, CAB 7090, New Brunswick, NJ 08903, 3 The Cancer Institute of New Jersey, New Brunswick, NJ 08903, 4 Environmental and Occupational Health Sciences Institute, Piscataway, NJ 08854, USA, 5 Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077, Göttingen, Germany and 6 Department of Biochemistry and Cellular Physiology, Josai University, Saitama, Japan
[SIZE=-1]*To whom correspondence should be addressed. Tel: +1 732 235 8460; Fax: +1 732 235 8473; Email: [email protected][/SIZE]
We synthesized a pentamine (3-3-3-3) and two hexamine (3-3-3-3-3 and 3-4-3-4-3) analogues of the natural polyamine, spermine (3-4-3) and studied their effectiveness in condensing pGL3 plasmid DNA, using light scattering and atomic force microscopic (AFM) techniques. The midpoint concentration of the polyamines on pGL3 condensation (EC50) was 11.3, 10.6, 1.5, 0.49 and 0.52 µM, respectively, for 3-4-3, norspermine (3-3-3), 3-3-3-3, 3-3-3-3-3 and 3-4-3-4-3 in 10 mM Na cacodylate buffer. Dynamic laser light scattering study showed a decrease in hydrodynamic radii of plasmid DNA particles as the number of positive charges on the polyamines increased. AFM data showed the presence of toroids with outer diameter of 117–191 nm for different polyamines, and a mean height of 2.61 ± 0.77 nm. AFM results also revealed the presence of intermediate structures, including those showing circumferential winding of DNA to toroids. The dependence of the EC50 on Na+ concentration suggests different modes of binding of spermine and its higher valent analogues with DNA. Our results show a 20-fold increase in the efficacy of hexamines for DNA condensation compared to spermine, and provide new insights into the mechanism(s) of DNA nanoparticle formation. These studies might help to develop novel nonviral gene delivery vehicles.
SourceMechanism of the formation of DNA–protein cross-links by antitumor cisplatin
Kateina Chválová, Viktor Brabec and Jana Ka
párková* Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, CZ-61265 Brno, Czech Republic![]()
[SIZE=-1]*To whom correspondence should be addressed. Tel: +420 541517174; Fax: +420 541240499; Email: [email protected][/SIZE]
[SIZE=-1]Received October 5, 2006.[/SIZE] [SIZE=-1]Revised January 2, 2007.[/SIZE] [SIZE=-1]Accepted January 5, 2007.[/SIZE]
DNA–protein cross-links are formed by various DNA-damaging agents including antitumor platinum drugs. The natures of these ternary DNA–Pt–protein complexes (DPCLs) can be inferred, yet much remains to be learned about their structures and mechanisms of formation. We investigated the origin of these DPCLs and their cellular processing on molecular level using gel electrophoresis shift assay. We show that in cell-free media cisplatin [cis-diamminedichloridoplatinum(II)] forms DPCLs more effectively than ineffective transplatin [trans-diamminedichloridoplatinum(II)]. Mechanisms of transformation of individual types of plain DNA adducts of the platinum complexes into the DPCLs in the presence of several DNA-binding proteins have been also investigated. The DPCLs are formed by the transformation of DNA monofunctional and intrastrand cross-links of cisplatin. In contrast, interstrand cross-links of cisplatin and monofunctional adducts of transplatin are stable in presence of the proteins. The DPCLs formed by cisplatin inhibit DNA polymerization or removal of these ternary lesions from DNA by nucleotide excision repair system more effectively than plain DNA intrastrand or monofunctional adducts. Thus, the bulky DNA–protein cross-links formed by cisplatin represent a more distinct and persisting structural motif recognized by the components of downstream cellular systems processing DNA damage considerably differently than the plain DNA adducts of this metallodrug.
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors.
CFSM said:It was He who created all that we see and all that we feel. We feel strongly that the overwhelming scientific evidence pointing towards evolutionary processes is nothing but a coincidence, put in place by Him.
YOU ARE POSTING ONE PICTURE FOR WHICH I HAVE GIVEN A DETAIL ANSWER AGAIN AND AGAIN.P.S: if you understand the Pastarfarian position it never denies the validity of scientific method or the conclusions it reaches.
Originally Posted by CFSM
It was He who created all that we see and all that we feel. We feel strongly that the overwhelming scientific evidence pointing towards evolutionary processes is nothing but a coincidence, put in place by Him.
YOU ARE POSTING ONE PICTURE FOR WHICH I HAVE GIVEN A DETAIL ANSWER AGAIN AND AGAIN.
YOUR SELECTION OF A RELIGION Pastarfarian HAS JUST A PURPOSE TO SUPPORT AND ANSWER THE QUESTION WHO MADE THE ORIGIN, THEN AS YOU ASK FROM US WHO MADE YOUR GOD , WE CAN ALSO ASK WHO HAS CREATED YOUR THAT GOD .....
YOUR DISCUSSION IS JUST A PERSONAL ITERPRETITION OKHTAR CONCLUDE CORRECT THAT However certain circles insisted on revising, renewing, and raising the theory up to a scientific platform. All these efforts were very meaningful in indicating that behind the theory laid some ideological intentions rather than scientific concerns.
Quit the pedantic bullshit, just give me an answer about sea salt.
post here okhtar statement with reference i will answer you for your misunderstaning
Mr. Hafizaad, ko hangilada?