Thanks much Robert.
I hope to soon delve into Meselson-Stahl in depth, but for now
I found an article regarding their classical experiment, at
"Stahl’s role in the project involved the preparation of
the phage samples, and he performed comprehensive
analyses of the sedimentation data. A long detour
transpired because of the inability to
detect phage or DNA molecules"
"...Meselson wrote in his workbook about the need to
abandon phage DNA and use bacterial DNA..."
Apparently they gave up on phages because they couldn't detect phage DNA,
and so used bacteria, e. coli.
On Thu, 9 Sep 2010 08:15:00 +1200, Robert Mann <[log in to unmask]>
>Jim West queried whether bacteriophages are a proven entity.
>The core of his querying was:
>>I am skeptical of phage as virus theory, because, there is a parallel, HIV.
> Earlier, Stuart Newman had given us an impeccable summary:
>> >>From: Stuart Newman <[log in to unmask]>
>>>>Sent: Sep 6, 2010 5:34 PM
>>>>To: [log in to unmask]
>>>>Subject: Re: Phage Therapy
>>>>There is a confusion here, Mitchel. Marcophages are cells of the animal
>>>>(e.g., human) immune system which scavenge debris, including bacteria
>>>>that have been killed by antibiotics or are bound to antibodies produced
>>>>by plasma cells. They are entirely different from bacteriophages, which
>>>>are viruses directed against bacteria and not endogenous to the immune
>>>>system. Bacteriophage therapy was what the character Arrowsmith was
>>>>studying, what the Russians greatly advanced, and what is attracting
>>>>increasing interest from mainstream medical science, e.g.,
> Not having been directly involved in the disputes on this
>list about HIV or about (bacterio)phages, let me now confirm what
>Stuart wrote. As for whether phages have ever been isolated or
>properly, unambiguously observed, I was in the field of molecular
>biology when these babies were a centre of attention. I would say
>that the biological category 'bacteriophage' is practically as clear
>& confirmed as 'bacteria'. For any who doubt, perhaps the famous
>Meselson/Stahl expt will help - a glimpse of how well understood
>these things were, 4 decades ago. There is no scientific doubt that
>these viruses of bacteria are real, and many of them have been
>characterised in great detail.
> Whether some of them will enter medical practice as
>therapeutic agents is less clear, as shown by the review Stuart
>referred us to.
> But whether phages are real is not in doubt.