EXHIBIT 10.8



SECOND AMENDED AND RESTATED
REVOLVING CREDIT NOTE

$3,000,000                                                      FEBRUARY 7, 2000

     FOR  VALUE  RECEIVED,   INFORMAX,   INC.,  a  Delaware   corporation   (the
"BORROWER"), promises to pay to the order of PNC BANK, NATIONAL ASSOCIATION (the
"BANK"),  in  lawful  money of the  United  States  of  America  in  immediately
available  funds,  the  principal  sum of the  lesser of THREE  MILLION  DOLLARS
($3,000,000)  (the "REVOLVING  CREDIT") or the aggregate unpaid principal amount
outstanding as of the Revolving Credit  Expiration Date,  together with interest
accruing on the outstanding  principal balance from the date hereof, as provided
below:

     1.  LOAN  AGREEMENT.  This  Note is  issued  in  connection  with  the Loan
Agreement  dated as of May 6, 1999 by and between the Borrower and the Bank,  as
amended by Amendment No. 1 to Loan Agreement dated August 6, 1999, Amendment No.
2 to Loan  Agreement  dated  November  30,  1999  and  Amendment  No.  3 to Loan
Agreement dated the date hereof,  the terms of which are incorporated  herein by
reference  (as amended,  the "LOAN  AGREEMENT"),  and is secured by the property
described in the Security Agreement by and between the Borrower and the Bank and
other loan  documents  entered into in connection  with the Loan  Agreement (the
"LOAN  DOCUMENTS")  and by such other  collateral as previously may have been or
may in the future be granted  to the Bank to secure  this Note and the  November
1999 Note (defined below).

     2. RATE OF INTEREST. Amounts outstanding under this Note will bear interest
at a rate per annum  determined in accordance with the Loan Agreement.  Interest
will be  calculated  on the basis of a year of 360 days for the actual number of
days in each interest period.

     3. ADVANCES.  The Borrower may borrow,  repay and reborrow  hereunder until
the Revolving  Credit  Expiration  Date,  subject to the terms and conditions of
this Note and the Loan  Documents (as defined  herein).  The  "REVOLVING  CREDIT
EXPIRATION  DATE" shall mean  February  2,  2001,  or such later date as may be
agreed by the Bank and Borrower. The Borrower acknowledges and agrees that in no
event  will the Bank be under any  obligation  to extend or renew the  Revolving
Credit or this Note beyond  February 2, 2001.  In no event shall the  aggregate
unpaid  principal  amount of advances  under this Note exceed the face amount of
this Note.

     4. PAYMENT TERMS.  Accrued interest will be due and payable on the 15th day
of each month, beginning with the payment due, if any, on February 15, 2000. The
outstanding  principal  balance and any accrued but unpaid interest shall be due
and payable on the Revolving  Credit  Expiration Date. If any payment under this
Note shall become due on a Saturday,  Sunday or public holiday under the laws of
the  Commonwealth  of  Pennsylvania,  such  payment  shall  be made on the  next
succeeding  business  day and  such  extension  of time  shall  be  included  in


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computing  interest  in  connection  with  such  payment.  The  Borrower  hereby
authorizes the Bank to charge the Borrower's deposit account at the Bank for any
payment when due hereunder.  Payments received will be applied to charges,  fees
and  expenses  (including  reasonable  attorney's  fees),  accrued  interest and
principal in any order the Bank may choose, in its sole discretion.

     5. DEFAULT. The occurrence of any one or more of the following events shall
constitute a "DEFAULT":

          (a) the  Borrower  shall fail to pay all or any portion of interest or
     principal on this Note when due; or

          (b) an Event of Default shall occur under the Loan  Agreement or other
     Loan Documents.

Upon occurrence of a Default, the entire outstanding principal balance, together
with all interest, costs, charges and other amounts outstanding under this Note,
shall  become  immediately  due and payable  and,  upon such  acceleration,  all
amounts due hereunder shall bear interest at the Default Rate (defined below).

     6. LATE  PAYMENTS;  DEFAULT RATE. If the Borrower fails to make any payment
of  principal  when due or any payment of interest  or other  amount  coming due
pursuant to the  provisions  of this Note within five (5)  business  days of the
date due and  payable,  the  Borrower  also shall pay to the Bank a late  charge
equal to the lesser of five  percent (5%) of the amount of such payment or $500.
Such five (5)  business  day period  shall not be construed in any way to extend
the due date of any such payment.  The late charge is imposed for the purpose of
defraying the Bank's  expenses  incident to the handling of delinquent  payments
and is in  addition  to,  and not in lieu of,  the  exercise  by the Bank of any
rights  and  remedies  hereunder,  under  the  other  Loan  Documents  or  under
applicable  law, and any reasonable fees and expenses of any agents or attorneys
which the Bank may employ.  At the option of the Bank upon the occurrence of any
Event of Default (as defined in the Loan  Agreement) and during the  continuance
thereof,  this Note shall bear  interest at a rate per annum (based on a year of
360 days and actual days elapsed) which shall be two  percentage  points (2%) in
excess of the interest  rate in effect from time to time under this Note but not
more than the maximum rate allowed by law (the "DEFAULT RATE"). The Default Rate
shall continue to apply whether or not judgment shall be entered on this Note.

     7. PREPAYMENT.  The  indebtedness  evidenced by this Note may be prepaid in
whole or in part at any time without penalty.

     8. NO NOVATION.  This Second Amended and Restated  Revolving Credit Note is
issued in replacement for the Amended and Restated  Revolving  Credit Note dated
November 30, 1999 made by the  Borrower,  under the terms of the Loan  Agreement
(the "NOVEMBER 1999 NOTE"). The indebtedness evidenced by the November 1999 Note
is continuing  indebtedness


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and  nothing  herein  shall be deemed to  constitute  a payment,  settlement  or
novation of the November 1999 Note, or release or otherwise adversely affect any
rights of the Bank against the Borrower  and all amounts  outstanding  under the
November  1999 Note shall be  transferred  to,  and be deemed to be  outstanding
under, this Second Amended and Restated Revolving Credit Note.

     9. MISCELLANEOUS. No delay or omission of the Bank to exercise any right or
power arising hereunder shall impair any such right or power or be considered to
be a waiver of any such right or power,  nor shall the Bank's action or inaction
impair any such right or power.  The  Borrower  agrees to pay on demand,  to the
extent  permitted  by law,  all costs and  expenses  incurred by the Bank in the
enforcement of its rights in this Note and in any security  therefor,  including
without  limitation  reasonable fees and expenses of the Bank's counsel.  If any
provision  of this  Note is  found  to be  invalid  by a  court,  all the  other
provisions  of this Note will remain in full force and effect.  The Borrower and
all other makers and indorsers of this Note hereby  forever  waive  presentment,
protest, notice of dishonor and notice of non-payment.  The Borrower also waives
all defenses  based on suretyship or impairment of  collateral,  except for such
impairment which results from the gross negligence or willful  misconduct of the
Bank.   This  Note  shall   bind  the   Borrower   and  its  heirs,   executors,
administrators,  successors and assigns,  and the benefits hereof shall inure to
the benefit of the Bank and its successors and assigns.

     10.  GOVERNING  LAW.  THIS NOTE has been  delivered to the Bank and will be
deemed  to be  made in the  Commonwealth  of  Pennsylvania.  THIS  NOTE  WILL BE
INTERPRETED  AND THE  RIGHTS  AND  LIABILITIES  OF THE  BORROWER  AND  THE  BANK
DETERMINED  IN ACCORDANCE  WITH THE LAWS OF THE  COMMONWEALTH  OF  PENNSYLVANIA,
EXCLUDING ITS CONFLICT OF LAWS RULES. The Borrower hereby  irrevocably  consents
to the exclusive  jurisdiction of any state or federal court seated in Allegheny
County,  Pennsylvania,  and  consents  that all  service  of  process be sent by
nationally  recognized overnight courier service directed to the Borrower at the
Borrower's  address set forth in the Loan  Agreement and service so made will be
deemed to be  completed on the  business  day after  deposit with such  courier;
provided that nothing contained in this Note will prevent the Bank from bringing
any action, enforcing any award or judgment or exercising any rights against the
Borrower  individually,  against any  security  or against  any  property of the
Borrower   within  any  other  county,   state  or  other  foreign  or  domestic
jurisdiction.  The  Borrower  agrees that the venue  provided  above is the most
convenient  forum for both the Bank and the  Borrower.  The Borrower  waives any
objection to venue and any  objection  based on a more  convenient  forum in any
action instituted under this Note.

     11.  WAIVER OF JURY  TRIAL.  THE  BORROWER  IRREVOCABLY  WAIVES ANY AND ALL
RIGHTS THE  BORROWER  MAY HAVE TO A TRIAL BY JURY IN ANY ACTION,  PROCEEDING  OR
CLAIM OF ANY NATURE RELATING TO THIS NOTE, ANY DOCUMENTS  EXECUTED IN CONNECTION


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WITH THIS NOTE OR ANY TRANSACTION  CONTEMPLATED  IN ANY OF SUCH  DOCUMENTS.  THE
BORROWER ACKNOWLEDGES THAT THE FOREGOING WAIVER IS KNOWING AND VOLUNTARY.

     The  Borrower  acknowledges  that it has  read  and  understood  all of the
provisions of this Note, including waiver of jury trial, and has been advised by
counsel as necessary or appropriate.

     WITNESS the due  execution of this Second  Amended and  Restated  Revolving
Credit Note as a document under seal, as of the date first written  above,  with
the intent to be legally bound hereby.



                                       INFORMAX, INC.


                                       By: /s/ Alex Titomirov
                                          -------------------------------

                                       Name: Alex Titomirov
                                            -----------------------------

                                       Title: CEO
                                             ----------------------------



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