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                                                                     EXHIBIT 4.8


                                 INFORMAX, INC.

                             STOCK OPTION AGREEMENT


       This Stock Option Agreement (the "Agreement") is made as of the December
11, 1997, by and between InforMax, Inc., a corporation organized and existing
under the laws of Delaware (the "Corporation") and Vadim Babenko (the
"Optionee").

              Recital: The Corporation has determined that it is desirable to
       recognize the contributions made to the Corporation by the Optionee, the
       Corporation intends to grant hereunder to the Optionee an option to
       purchase a certain number of shares of common stock of the Corporation,
       all according to the terms and conditions set forth herein;

       NOW, THEREFORE, in consideration of the foregoing and of the mutual
covenants and agreements set forth herein, the parties hereto agree as follows:

                              W I T N E S S E T H:

       1.     Grant of Option. The Corporation hereby affirms the grant to the
Optionee, as of December 11, 1997 (the "Original Grant Date"), the right and
option (the "Option") to purchase from the Corporation, on the terms and subject
to the conditions hereinafter set forth, Four Thousand (4000) shares of common
nonvoting stock of the Corporation (the "Stock"). The Option shall not
constitute an "incentive stock option" within the meaning of Section 422A of
the Internal Revenue Code of 1986, as amended (the "Code"). Corporation
reserves 4000 shares for Optionee to be exercised as described in Section 3.


       2.     Price. The purchase price (the "Option Price") for the shares of
Stock subject to the Option granted by this Agreement shall be $1 per share and
this Agreement will supersede all previous Option Agreements or Arrangements.

       3.     Exercise of Option. Except as otherwise provided herein, the
Option shall be exercised as follows:

              A.     Option Terms. Until the Option is terminated, the Optionee
       may exercise the Option (up to the total number of shares set forth in
       Section 1 above) in whole or in part, at any time and from time to time,
       by delivering written notice of the intention to exercise the Option
       along with proper payment therefore, provided, that in no event may the
       Option


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       be exercised for a fractional share.


              B.     Exercise by Optionee. During the lifetime of the Optionee,
       only the Optionee (or, in the event of the Optionee's legal incapacity or
       incompetence, the Optionee's guardian or legal representative) may
       exercise the Option.

              C.     Termination of Employment. In the event that the Optionee
       is employed by the Corporation, except as provided in subsections D and E
       of this Section 3 the Optionee may exercise the Option only while the
       Optionee is employed by the Corporation or for three months after the
       termination of his employment, after which period the Option shall
       terminate.

              D.     Death. In the event of the Optionee's death prior to the
       termination of the Option, the Optionee's personal representative and/or
       other successors-in-interest, as the case may be, shall have the right
       (subject to the limitations on exercise set forth in Subsection F below)
       to exercise all or any part of the Option.

              E.     Disability. If the Optionee's termination of employment is
       by reason of "permanent and total disability" (within the meaning of
       Section 22 (e) (3) of the Internal Revenue Code), the Optionee or his
       guardian or legal representative shall have the right (subject to the
       limitations on exercise set forth in Subsection F below) to exercise all
       or any part of the Option.

              F.     Limitations on Exercise of Option. Notwithstanding the
       foregoing provisions of this Section 3, in no event may the Option be
       exercised, in whole or in part, more than ten years following the
       Original Grant Date, or after the occurrence of an event referred to in
       Section 7 below that results in termination of the Option.

       4.     How to Exercise the Option. Subject to the terms and conditions of
this Agreement, the Option may be exercised by delivering written notice of
exercise to the Corporation, at its principal office. Such notice shall specify
the number of shares for which the Option is being exercised and shall be
accompanied by payment in full of the Option Price of the shares for which the
Option is being exercised. Payment of the Option Price for the shares of Stock
purchased pursuant to the exercise of the Option shall be made either (i) in
cash or in cash equivalent; (ii) through the tender to the Corporation of shares
of stock, which shares shall be valued, for the purposes of determining the
extent to which the Option Price has been paid thereby, at their fair market
value (as determined by the Board of Directors of the Corporation) on the date
of exercise; or (iii) by a combination


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of the methods described in (i) and (ii). If the person exercising the Option is
not the Optionee, such person shall also deliver with the notice of exercise
appropriate proof of his or her right to exercise the Option. An attempt to
exercise the Option granted hereunder other than as set forth above shall be
invalid and of no force and effect. Promptly after proper exercise of the Option
as provided for above, the Corporation shall deliver to the person exercising
the Option a certificate or certificates for the shares of Stock being
purchased;

       5.     Limitations on Transfer. The Option is not transferable by the
Optionee, other than by will or the laws of descent and distribution in the
event of death of the Optionee.

       6.     Rights as Stockholder. No person shall have any of the rights or
privileges of a stockholder of the Corporation in respect of any shares of Stock
transferable hereunder unless and until (a) such shares have been fully paid and
certificates representing such shares have been endorsed, transferred and
delivered, (b) the name of the person entitled to exercise the Option has been
entered as the stockholder of record on the books of the Corporation, and (c)
the person entitled to exercise the Option has taken all steps and executed all
documents required of all other stockholders of the Corporation, including
without limitation evidencing proper agreement to be bound by the terms of any
Stockholder's Agreement that may then be in effect.

       7.     Effect of Changes in Capitalization.

              A.     Changes in Stock. If the outstanding shares of Stock are
       increased or decreased or changed into or exchanged for a different
       number or kind of shares or other securities of the Corporation by reason
       of any recapitalization, reclassification, stock split-up, combination of
       shares, exchange of shares, stock dividend or other distribution payable
       in capital stock, or other increase or decrease in such shares effected
       without receipt of consideration by the Corporation occurring after the
       date the Option is granted, to preserve and protect any rights he may
       have pursuant hereunder, the Optionee may exercise his Option before such
       event occurs. In such event, the Optionee shall have the right for 30
       days immediately prior to the occurrence of such event to exercise the
       Option in whole or in part. The Corporation shall send written notice of
       such event to the Optionee not later than the time at which the
       Corporation gives notice thereof to its stockholders.

              B.     Reorganization in Which the Corporation is the Surviving
       Corporation. Subject to Subsection C of this Section 7, if the
       Corporation shall be the surviving corporation in any one or more other
       corporations, to preserve and protect any rights he may have hereunder
       the


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       Optionee may exercise the Option prior to the event of reorganization,
       merger or consolidation. In such event, the Optionee shall have the right
       for 30 days immediately prior to the occurrence of such event to exercise
       the Option in whole or in part. The Corporation shall send written notice
       of such event to the Optionee not later than the time at which the
       Corporation gives notice thereof to its stockholders.

              C.     Reorganization in Which the Corporation Is Not the
       Surviving Corporation or Sale of Assets or Stock. Upon the dissolution or
       liquidation of the Corporation, or upon a merger, consolidation or
       reorganization of the Corporation with one or more other corporations in
       which the Corporation is not the surviving corporation, or upon a sale of
       substantially all of the assets of the Corporation to another
       corporation, or upon any transaction (including, with limitation, a
       merger or reorganization in which the Corporation is the surviving
       corporation) approved by the Board of Directors of the Corporation which
       results in any person or entity owning eighty percent (80%) or more of
       the combined voting power of all classes of stock of the Corporation, the
       Option hereunder shall terminate, except to the extent provision is made
       in connection with such transaction for the continuation and/or the
       assumption of the Option, or for the substitution for the Option of new
       Options or stock appreciation rights covering the stock of a successor
       employer corporation, or a parent or subsidiary thereof, with appropriate
       adjustments as to the number and kinds of shares and exercise prices, in
       which event the Option shall continue in the manner and under the terms
       so provided. In such event, the Optionee shall have the right for 30 days
       immediately prior to the occurrence of such termination to exercise the
       Option in whole or in part. The Corporation shall send written notice of
       an event that will result in such a termination to the Optionee not later
       than the time at which the Corporation gives notice thereof to its
       stockholders.

              D.     Adjustments. Adjustments specified in this Section relating
       to stock or securities of the Corporation shall be made by the Board of
       Directors of the Corporation, whose determination in that respect shall
       be final, binding and conclusive. No fractional shares of Stock or units
       of other securities shall be issued pursuant to any such adjustment, and
       such fractional shares shall be eliminated in each case by rounding
       downward to the nearest whole share or unit.

       8.     General Restrictions. The Corporation shall not be required to
sell or issue any shares of Stock under the Option if the sale or issuance of
such shares would constitute a violation by the individual exercising the Option
or by the Corporation of

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any provision of any law or regulation of any governmental authority, including,
without limitation, any U.S. Federal securities laws or regulations or any U.S.
state securities laws or regulations. If at any time the Corporation shall
determine, in its discretion, that the listing, registration or qualification of
any shares subject to the Option upon any securities exchange or under any
state, or federal law, or the consent or approval of any government regulatory
body is necessary or desirable as a condition of, or in connection with, the
issuance or purchase of share, the Option may not be exercised in whole or in
part unless such listing, registration, qualification, consent of approval shall
have been effected or obtained free of any conditions that are unacceptable to
the Corporation, and delay caused thereby or failure of the Corporation to take
necessary steps in pursuit thereof shall prolong the date of termination of the
Option for the time required to finalize mentioned above procedures.

        9.   Withholding of Taxes. The Parties hereto recognize that the
Corporation may be obligated to withhold federal and local income taxes and
Social Security taxes to the extent that the Optionee realizes ordinary income
in connection with the exercise of the Option. The Optionee agrees that the
Corporation may withhold amounts needed to cover such taxes from payments
otherwise due and owing to the Optionee, and also agrees that upon demand the
Optionee will promptly pay to the Corporation having such obligation any
additional amounts as may be necessary to satisfy such withholding tax
obligation. Such payment shall be made in cash or equivalent.

        10.  Disclaimer of Rights. No provision in this Agreement shall be
construed to confer upon the Optionee the right to be employed by the
Corporation, or to interfere an any way with the right and authority of the
Corporation either to increase or decrease the compensation of the Optionee at
any time, or to terminate any employment or other relationship between the
Optionee and the Corporation.

        11.  Interpretation of this Agreement. All decisions of the Board of
Directors of the Corporation with regard to any questions arising under this
Agreement shall be binding and conclusive on the Corporation and the Optionee
and any other person entitled to exercise the Option as provided for herein.

        12.  Governing Law. This Agreement is executed pursuant to and shall be
governed by the laws of the State of Maryland (but not including the choice of
law rules thereof).

        13.  Binding Effect. Subject to all restrictions provided for in this
Agreement and the Option provided for herein, this Agreement shall be biding
upon and inure to the benefit of the parties hereto and their respective heirs,
executors,


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administrators, successors and assigns.

        14.  Notice. Any notice hereunder by the Optionee to the Corporation
shall be in writing and shall be deemed duly given if mailed or delivered to the
Corporation at its principal office, or if so mailed or delivered to such other
address as the Corporation may hereafter designate by notice to the Optionee.
Any notice hereunder by the Corporation to the Optionee shall be in writing and
shall be deemed duly given if mailed or delivered to the Optionee at the address
specified below by the Optionee for such purpose, or if so mailed or delivered
to such other address as the Optionee may hereafter designate by written notice
given the Corporation.

        15.  Entire Agreement. This Agreement constitutes the entire agreement
and supersedes all prior understandings and agreements, written or oral, of the
parties hereto with respect to the subject matter hereof, including, but not
limited to, the Agreement. Neither this Agreement nor any term hereof may be
amended, waived, discharged, or terminated except by a written instrument signed
by the Corporation unilaterally may waive any provision hereof in writing to the
extent that such a waiver does not adversely affect the interests of the
Optionee hereunder, but no such waiver shall operate as or be construed to be a
subsequent waiver of the same provision or a waiver of any other provision
hereof.

        IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement, or caused this Agreement to be duly executed on their behalf, as of
the day and year first above written.


        InforMax, Inc.                           Optionee

        By:    /s/ ALEX TITOMIROV                 By:  /s/ VADIM BABENKO
           ----------------------                  ---------------------
        Name:  ALEX TITOMIROV
             --------------------
        Title: PRESIDENT/CEO                    Name:  VADIM BABENKO
             --------------------                     ------------------

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                  FIRST AMENDMENT TO THE STOCK OPTION AGREEMENT


               THIS FIRST AMENDMENT to the STOCK OPTION AGREEMENT (the
"Amendment") is effective as of January 1, 1999, by and between InforMax, Inc.,
a Delaware corporation ("Corporation"), and Vadim Babenko ("Optionee").

               WHEREAS, pursuant to Section 15 of the Stock Option Agreement
between Corporation and Optionee dated December 11, 1997 (the "Stock Option
Agreement"), the parties hereto desire to amend certain provisions of the Stock
Option Agreement to clarify Optionee's rights in the event of a change in
capitalization of Corporation;

               NOW, THEREFORE, in consideration of the foregoing and the mutual
covenants and agreements hereinafter set forth, the parties do hereby agree as
follows:

               1. DEFINITIONS. Capitalized terms used herein and not defined
herein shall have the meanings ascribed to such terms in the Stock Option
Agreement, as amended by this Amendment.

               2. SECTION 7.A. Section 7.A is amended and replaced in its
entirety with the following:

               "A. Changes in Stock. If the outstanding shares of Stock are
increased or decreased or changed into or exchanged for a different number or
kind of shares or other securities of the Company by reason of any
recapitalization, reclassification, stock split-up, combination of shares,
exchange of shares, stock dividend or other distribution payable in capital
stock, or other increase or decrease in such shares effected without receipt of
consideration by the Company occurring after the date the Option is granted, a
proportionate and appropriate adjustment shall be made by the Company in the
number and kind of shares subject to the Option, so that the proportionate
interest of the Optionee immediately following such event shall, to the extent
practicable, be the same as immediately prior to such event. Any such adjustment
in the Option shall not change the total Option Price with respect to shares
subject to the unexercised portion of the Option but shall include a
corresponding proportionate adjustment in the Option Price per share."

               3. SECTION 7.B. Section 7.B is amended and replaced in its
entirety with the following:

               "B. Reorganization in Which the Company Is the Surviving
Corporation. Subject to Subsection C of this Section, if the Company shall be
the surviving corporation in any reorganization, merger or consolidation of the
Company with one or more other corporations, the Option shall pertain to and

                                       1
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apply to the securities to which a holder of the number of shares of Stock
subject to the Option would have been entitled immediately following such
reorganization, merger or consolidation, with a corresponding proportionate
adjustment of the Option Price per share so that the aggregate Option Price
thereafter shall be the same as the aggregate Option Price of the shares
remaining subject to the Option immediately prior to such reorganization, merger
or consolidation."

                4.     CONTINUED EFFECT. Except as modified herein, all terms
and conditions of the Stock Option Agreement shall remain in full force and
effect, which terms and conditions the parties hereby ratify and affirm.

                5.     INTENT. The parties intend that this Amendment apply to
the stock split of the Corporation's capital stock, which occurred on March 29,
1999.

                6.     COUNTERPARTS. To facilitate execution, this Amendment may
be executed in counterparts, and all counterparts shall collectively constitute
a single agreement.

                IN WITNESS WHEREOF, the parties have executed this Amendment as
of the date first above written.

INFORMAX, INC.                              OPTIONEE

By: /s/ Alex Titomirov                      By: /s/ VADIM  BABENKO
   ---------------------                        ---------------------------
Alex Titomirov                              Name:
Chairman and CEO                                 --------------------------
                                            Date:     April 9, 1999
                                                 --------------------------
Date:  4/9/99
     -------------------



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