<PAGE>

                                                                  Exhibit 10.33
                                                                  -------------

                                PROMISSORY NOTE
                                ---------------
                                    1158-002

                                                           Date:  July 23, 1999


     FOR VALUE RECEIVED, the undersigned promises to pay to the order of
Transamerica Business Credit Corporation or its assigns (the "Payee") at its
office located at Riverway II, West Office Tower, 9399 West Higgins Road,
Rosemont, Illinois 60018, or at such other place as the Payee or the holder
hereof may designate in writing, the principal amount of Two Million and Dollars
($2,000,000) received by the undersigned, plus interest, in lawful money of the
United States and in immediately available funds. Interest only payments shall
be payable commencing September 1, 1999 and continuing through February 1, 2002
in the amounts set forth on Exhibit I.  Thereafter, interest and principal
payments shall be due in six consecutive monthly installments of Three Hundred
Forty Six Thousand, Five Hundred Seventy and 78/100 Dollars ($346,570.78).  No
amount of principal paid or prepaid hereunder may be reborrowed.

     This Note is one of the Notes referred to in the Loan and Security
Agreement dated as of July 20, 1999 (as amended, supplemented or otherwise
modified from time to time, the "Agreement"), between the undersigned and the
Payee and is subject and entitled to all provisions and benefits thereof.
Capitalized terms used but not defined herein shall have the meanings set forth
in the Agreement.

     If any installment of this Note is not paid within five days after its due
date, the undersigned agrees to pay on demand, in addition to the amount of such
installment, an amount equal to 5% of such installment, but only to the extent
permitted by Applicable Law.

     The undersigned shall have the right to prepay this Note at any time on or
after September 1, 2000, on thirty days' prior written notice to the Payee.  On
the date of any such prepayment, the undersigned shall pay an amount equal to
the present value of the remaining payments (principal and interest) due
hereunder discounted at 6% simple interest per annum, together with all
interest, fees and other amounts payable on the amount so prepaid or in
connection therewith to the date of such prepayment.  Any prepayments shall be
applied to the installments hereof in the inverse order of maturity.

     Upon the maturity of this Note, the entire unpaid principal amount on this
Note, together with all interest, fees and other amounts payable hereon or in
connection herewith, shall be immediately due and payable without further notice
or demand, with interest on all such amounts at a rate not to exceed the lawful
limit, from the date of such maturity or acceleration, as the case may be, until
all such amounts have been paid.  Upon default or the acceleration of the
maturity of this Note in accordance with the terms of the Agreement, the entire
unpaid principal amount on this Note, together with all interest, fees,
prepayment fees and charges in an amount equal to the present value of the
remaining payments (principal and interest) due hereunder discounted at 6%
simple interest per annum and other amounts payable hereon or in connection
herewith, shall be immediately due and payable without further notice or demand,
with interest on all such
<PAGE>

amounts at a rate not to exceed the lawful limit, from the date of such
maturity, default or acceleration, as the case may be, until all such amounts
have been paid.

     If any payment on this Note becomes payable on a day other than a Business
Day, the maturity thereof shall be extended to the next succeeding Business Day.

     The undersigned hereby waives diligence, demand, presentment, protest and
notice of any kind, and assents to extensions of the time of payment, release,
surrender or substitution of security, or forbearance or other indulgence,
without notice.  The undersigned agrees to pay all amounts under this Note
without offset, deduction, claim, counterclaim, defense or recoupment, all of
which are hereby waived.

     The Payee, the undersigned and any other parties to the Loan Documents
intend to contract in strict compliance with applicable usury law from time to
time in effect.  In furtherance thereof such Persons stipulate and agree that
none of the terms and provisions contained in the Loan Documents shall ever be
construed to create a contract to pay, for the use, forbearance or detention of
money, interest in excess of the maximum amount of interest permitted to be
charged by Applicable Law from time to time in effect.  Neither the undersigned
nor any present or future guarantors, endorsers, or other Persons hereafter
becoming liable for payment of any Obligation shall ever be liable for unearned
interest thereon or shall ever be required to pay interest thereon in excess of
the maximum amount that may be lawfully charged under Applicable Law from time
to time in effect, and the provisions of this paragraph shall control over all
other provisions of the Loan Documents which may be in conflict or apparent
conflict herewith.  The Payee expressly disavows any intention to charge or
collect excessive unearned interest or finance charges in the event the maturity
of any Obligation is accelerated.  If (a) the maturity of any Obligation is
accelerated for any reason, (b) any Obligation is prepaid and as a result any
amounts held to constitute interest are determined to be in excess of the legal
maximum, or (c) the Payee or any other holder of any or all of the Obligations
shall otherwise collect amounts which are determined to constitute interest
which would otherwise increase the interest on any or all of the Obligations to
an amount in excess of that permitted to be charged by Applicable Law then in
effect, then all sums determined to constitute interest in excess of such legal
limit shall, without penalty, be promptly applied to reduce the then outstanding
principal of the related Obligations or, at the Payee's or such holder's option,
promptly returned to the undersigned upon such determination.  In determining
whether or not the interest paid or payable, under any specific circumstance,
exceeds the maximum amount permitted under Applicable Law, the Payee and the
undersigned (and any other payors thereof) shall to the greatest extent
permitted under Applicable Law, (i) characterize any non-principal payment as an
expense, fee or premium rather than as interest, (ii) exclude voluntary
prepayments and the effects thereof, and (iii) amortize, prorate, allocate, and
spread the total amount of interest through the entire contemplated term of this
Note in accordance with the amount outstanding from time to time thereunder and
the maximum legal rate of interest from time to time in effect under Applicable
Law in order to lawfully charge the maximum amount of interest permitted under
Applicable Law.

     This Note may not be changed, modified or terminated orally, but only by an
agreement in writing signed by the undersigned and the Payee or any holder
hereof.

                                       2
<PAGE>

     The undersigned shall, upon demand, pay to the Payee all costs and expenses
incurred by the Payee (including the reasonable fees and disbursements of
counsel) in connection with the preparation, execution and delivery of this Note
and all other Loan Documents, and in connection with the administration,
modification and amendment of the Loan Documents, and pay to the Payee all costs
and expenses (including the reasonable fees and disbursements of counsel) paid
or incurred by the Payee in (A) enforcing or defending its rights under or in
respect of this Note or any of the other Loan Documents, (B) collecting any of
the liabilities by the undersigned to the Payee or otherwise administering the
Loan Documents, (C) foreclosing or otherwise collecting upon any collateral and
(D) obtaining any legal, accounting or other advice in connection with any of
the foregoing.

     This Note shall be binding upon the successors and assigns of the
undersigned and inure to the benefit of the Payee and its successors, endorsees
and assigns.  If any term or provision of this Note shall be held invalid,
illegal or unenforceable, the validity of all other terms and provisions hereof
shall in no way be affected thereby.

     EACH OF THE UNDERSIGNED AND, BY ITS ACCEPTANCE HEREOF, THE PAYEE HEREBY
KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVES (TO THE FULLEST EXTENT PERMITTED
BY APPLICABLE LAW) ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY OF ANY DISPUTE
ARISING UNDER OR RELATING TO THIS NOTE AND AGREES THAT ANY SUCH DISPUTE SHALL BE
TRIED BEFORE A JUDGE SITTING WITHOUT A JURY.

     THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF
THE STATE OF ILLINOIS WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAW.


     PARADIGM GENETICS, INC.


                              By:    /s/ John A. Ryals
                                 --------------------------------
                                  Name:  John A. Ryals
                                        -------------------------
                                  Title: CEO, President
                                        -------------------------

                                       3
<PAGE>

                                   EXHIBIT 1

<TABLE>
<S>                                    <C>                   <C>                <C>                 <C>
                                       -------------------------------------------------------------------------------
PARADIGM GENETICS                       Rate Adjustment               7/16/99               5.57%               0.99%
1158-002, SENIOR TERM NOTE                                            1/29/99               4.58%              12.50%
                                       -------------------------------------------------------------------------------
</TABLE>

COMPOUND PERIOD                    Monthly
Nominal Annual Rate                 13.490%
Periodic Rate                       1.1242%
Daily Rate                         0.03747%

<TABLE>
<S>                        <C>                    <C>                  <C>           <C>
Event                         Start Date             Amount              Number       Period
   1  Loan                    23-Jul-99              2,000,000               1
   2  Payment                 01-Sep-99                   0.00              30        Monthly
   3  Payment                 01-Mar-02             346,570.78               6        Monthly
</TABLE>

AMORTIZATION SCHEDULE - Normal Amortization, 360 Day Year

<TABLE>
<CAPTION>
       #                Date              Payment           Interest           Principal           Balance
<S>               <C>                   <C>                <C>                <C>                <C>
Loan              23-Jul-99                                                             0.00       2,000,000.00
        1         01-Sept-99                 29,304.16          29,304.16               0.00       2,000,000.00
        2         01-Oct-99                  22,483.33          22,483.33               0.00       2,000,000.00
        3         01-Nov-99                  22,483.33          22,483.33               0.00       2,000,000.00
        4         01-Dec-99                  22,483.33          22,483.33               0.00       2,000,000.00
1999 Totals                                  96,754.15          96,754.15

        5         01-Jan-00                  22,483.33          22,483.33               0.00       2,000,000.00
        6         01-Feb-00                  22,483.33          22,483.33               0.00       2,000,000.00
        7         01-Mar-00                  22,483.33          22,483.33               0.00       2,000,000.00
        8         01-Apr-00                  22,483.33          22,483.33               0.00       2,000,000.00
        9         01-May-00                  22,483.33          22,483.33               0.00       2,000,000.00
       10         01-Jun-00                  22,483.33          22,483.33               0.00       2,000,000.00
       11         01-Jul-00                  22,483.33          22,483.33               0.00       2,000,000.00
       12         01-Aug-00                  22,483.33          22,483.33               0.00       2,000,000.00
       13         01-Sept-00                 22,483.33          22,483.33               0.00       2,000,000.00
       14         01-Oct-00                  22,483.33          22,483.33               0.00       2,000,000.00
       15         01-Nov-00                  22,483.33          22,483.33               0.00       2,000,000.00
       16         01-Dec-00                  22,483.33          22,483.33               0.00       2,000,000.00
2000 Totals                                 269,799.96         269,799.96               0.00       2,000,000.00

       17         01-Jan-01                  22,483.33          22,483.33               0.00       2,000,000.00
       18         01-Feb-01                  22,483.33          22,483.33               0.00       2,000,000.00
       19         01-Mar-01                  22,483.33          22,483.33               0.00       2,000,000.00
       20         01-Apr-01                  22,483.33          22,483.33               0.00       2,000,000.00
</TABLE>

                                       4
<PAGE>

<TABLE>
<S>               <C>                   <C>                <C>                <C>                <C>
       21         01-May-01                  22,483.33          22,483.33               0.00       2,000,000.00
       22         01-Jun-01                  22,483.33          22,483.33               0.00       2,000,000.00
       23         01-Jul-01                  22,483.33          22,483.33               0.00       2,000,000.00
       24         01-Aug-01                  22,483.33          22,483.33               0.00       2,000,000.00
       25         01-Sep-01                  22,483.33          22,483.33               0.00       2,000,000.00
       26         01-Oct-01                  22,483.33          22,483.33               0.00       2,000,000.00
       27         01-Nov-01                  22,483.33          22,483.33               0.00       2,000,000.00
       28         01-Dec-01                  22,483.33          22,483.33               0.00       2,000,000.00
2001 Totals                                 269,799.96         269,799.96               0.00

        29        01-Jan-02                  22,483.33          22,483.33               0.00       2,000,000.00
        30        01-Feb-02                  22,483.33          22,483.33               0.00       2,000,000.00
        31        01-Mar-02                 346,570.78          22,483.33         324,087.45       1,675,912.55
        32        01-Apr-02                 346,570.78          18,840.05         327,730.73       1,348,181.82
        33        01-May-02                 346,570.78          15,155.81         331,414.97       1,016,766.85
        34        01-Jun-02                 346,570.78          11,430.15         335,140.63         681,626.22
        35        01-Jul-02                 346,570.78           7,662.61         338,908.17         342,718.05
        36        01-Aug-02                 346,570.78           3,852.73         342,718.05               0.00
2002 Totals                               2,124,391.34         124,391.34       2,000,000.00

Grand Totals                              2,760,745.41         760,745.41       2,000,000.00
</TABLE>

                                       5