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TH3 DBPABT1ZXT 3F TH2 ROSPITAL

Dr. Bivers, Director

STUDISS ON PNW~OCOCCI.  'G-R CAIJSATIVB AGBN'T OF LOBA. PN3WONIA

            Dr. Avery and associates.

   3r. Avery and his associates have continued their work on the

transformation of one type pneumococcus to another. Eesults of previous

sork shelved that the essential transforming substance is desoxyribonucleic

acid.  If, under vroper conditions, desoxyribonucleic acid derived from a

smooth Type III pneumococcus is added to a culture of a rough variant of

Tee I pneumococcus, this variant becomes n smooth Type III pneumococcus.

In addition to the essential transforming agent, other factors are required

for transformation.  In last year's report was a description of work on the

accessory factors.  At that time it mas stated that rough variants, in

order to be transformed, had to be clumped either by agglutinating anti-

bodies or by some physical means; that a dialyzable factor in serum is

essential; and, finally, that a globulin factor, which may be obtained

from serum or certain organs, is required.

     Plork on the accessory factors has been continued during the past
year and it has been found that sodium pyrophosohate can act as the dialyz-
able factor and that the nondialyzable factor previously thought to be

globulin is actually albumin.  Evidence that it is albumin instead of

globulin has been.obtained by using exceedingly small amounts of crystal-
line albumin obtained by methods recently described by Cohn of Harvard.
As little as 300 micrograms of purified serum albumin per cubic centimeter
of culture medium can under the proper conditions be the decisive factor
determining prompt and typical transformation.


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      The idea, previously mentioned, that globulin instead of albumin

was one of the accessory factors for transformation can be explained in the

following manner.  Before testing human sera or serous fluids for their

ability to support transformation, it -nas customar-y to subject them to

heating (60oC. for 30 minutes) at their normal sli&tly alkaline reaction.

This was done in order to inactivate a serum enzyme, desoxyribonuclease,

which would otherwise depolvmerize and thus destro,y the transforming

activity of the specific nucleic acid present in the transforming system.

It is not necessary to heat purified serum albumin for this purpose, but

when it is heated under these conditions, the protein becomes more readily

precipitable at lower concentrations of salt.  Accordingly, it appears not

unlikely that the activity previously observed in globulin fractions of

the serum may have been due to such altered albumin.

      Pneumococci e,xhibit marked variability in colonial forms covering

a wide range of differences in contour, morphology and surf ace topography.

The colonial variants display all degrees of smoothness and roughness from

the glistening mucoid to the extremely granular and pebbled-surfaced colony.

These physical features are in many instances reflected in recognized

differences in biochemical and physiological properties of the cells.

Considerable information is available orith regard to alterations in the

ant igenic structure , serological behavior and virulence associated with

these colonial changes.  It seemed possible to Dr. Avery and his associates

that the principles and techniques of transformation might afford a

specific means of investigating the hereditary basis of this phenomenon.

Work along these lines has progressed favorably and findings to date are

summarized in the next two paragraphs.

i

The property of extreme roughness (XI?) as opposed to moderate            {


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roughness (MR) is apparently due to the lack of a factor or factors which

can be experimentally introduced into the cells by the techniques of

transformation.  The I%. factor is present in the desoxyribonucleic acid

fraction of the moderately rough variant and of smooth Type III organisms

as well.  The factor MR, which determines the change from extreme to

moderate roughness , can be introduced independently of the SIII factor.

Indeed, the XR forms cannot be transformed to encapsulated Tyl?e III

organisms until they have first been converted into 1.R cells, that is,

the B,IR factor must be introduced first, the reaction being ER--)MR--)SIII.

      This form of analysis is being oursued vrith three objectives

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in mind.  First, it is hoped that some information may be gained on the

nature of "competence", that property of cells which determines their

capacity to respond to a given specific stimulus or factor in transforma-

tion.  Second, such experiments may make possible further analysis of the

nature of the specificity of the transforming substances.  Third, the

demonstration that two factors, one for moderate roughness (MR), the other
for synthesis of capsular polysaccharide (SIII), each coexisting in the

same preparation of nucleic acid, can be selectively taken up by pneumo-

coccal cells and independently bring about development of the correspond-

ing traits, justifies the hope that the pneumococcal cell may prove a

delicate tool for the study of many hereditary characters at a biological

level heretofore unrealized by geneticists.

           ACUTE AND CRROONIC DISORD3.W OF TF3 LIV3R

             Dr. Hoagland and his associates.

      As stated in previous rc-ports, Navy Fat ients with infectious

hepatitis or epidemic jaundice were admitted to the Roclccfeller Hospital

for treatment and study.  Xent ion was made in last year's report that