<PAGE>

                                                                   EXHIBIT 10.13


                              AMENDED AND RESTATED
                            REVOLVING LOAN AGREEMENT

         THIS AMENDED AND RESTATED REVOLVING LOAN AGREEMENT, dated March 8,
2000, by and between Transgenomic, Inc., a Delaware corporation ("BORROWER") and
First National Bank of Omaha, a national banking association with principal
business offices in Omaha, Nebraska ("BANK").

                              W I T N E S S E T H:

         Background. Whereas, BANK and Cetac Technologies, Inc. originally
executed a Revolving Loan agreement March 14, 1997. Subsequently, Cetac Holding
Company, Inc. acquired all assets and liabilities of Cetac Technologies, Inc.,
and on July 1, 1997, Cetac Holding Company, Inc. was merged into Transgenomic,
Inc., a Delaware corporation. Whereas, Transgenomic, Inc. is the surviving
corporation and is now known to BANK as the BORROWER.

Subsequently, BANK and BORROWER executed a Revolving Loan Agreement September
17, 1997, which has been amended from time to time (said Agreement together with
all amendments are herein referred to as the "ORIGINAL AGREEMENT"), pursuant to
which BANK agreed to make available to BORROWER a revolving line of credit
("REVOLVING CREDIT FACILITY").

                  Therefore, in consideration of the promises herein contained,
and each intending to be legally bound thereby, the parties agree as follows:

Section I. Definitions as used herein:

          1. "ACCOUNTS" "CHATTEL PAPER", "CONTRACTS", "DOCUMENTS", "EQUIPMENT",
"FIXTURES", "GENERAL INTANGIBLES", "GOODS", "INSTRUMENTS", "INVESTMENT PROPERTY"
and "INVENTORY" shall have the same meaning as is given that term in the Uniform
Commercial Code as presently adopted and in effect in the State of Nebraska.

          2. ACCOUNTING. Accounting terms used and not otherwise defined in this
AGREEMENT have the meanings determined by, and all calculations with respect to
accounting or financial matters unless otherwise provided herein shall be
computed in accordance with, GAAP.

          3. "AFFILIATE" means as to any PERSON, each other PERSON that directly
or indirectly, through one or more intermediaries, controls, or is controlled
by, or under common control with, such PERSON.


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<PAGE>

          4. "AGREEMENT" means this Agreement, as the same may from time to time
be amended or supplemented.

          5. "BORROWING BASE" means, at any time, the amount computed as Total
Borrowing Base on the BORROWING BASE CERTIFICATE most recently delivered to, and
accepted by, the BANK in accordance with this AGREEMENT, and equal to the lesser
of:

                  A. $5,000,000.00; or

                  B. The aggregate of (i) eighty percent (80%) of ELIGIBLE
         ACCOUNTS of the BORROWER, plus (ii) fifty percent (50%) of the Ending
         Inventory of BORROWER at cost (not to exceed $1,500,000.00). It is
         provided, however, that for purposes of the foregoing computation, no
         more than fifty percent (50%) of ELIGIBLE ACCOUNTS used in the
         foregoing computation may consist of Accounts due from non-United
         States entities. It is further provided, however, no demo Inventory of
         BORROWER located outside of the United States shall be included in such
         computation.

          6. "BORROWING BASE CERTIFICATE" means a fully completed certificate
certified by the chief financial officer of the BORROWER to be correct and
delivered to, and accepted by, the BANK. Attached hereto, marked Exhibit "A" and
by this reference made a part hereof is a form of BORROWING BASE CERTIFICATE,
acceptable to BANK, which shall, effective immediately, be used by the parties.

          7. "COLLATERAL" has the meaning given to such term in Section IV.

          8. "COLLATERAL DOCUMENTS" means the note, financing statements and
other documents required by BANK as set forth herein, together with any real
estate mortgage or deed of trust documents used in this transaction.

          9. "ELIGIBLE ACCOUNT" means, at any time, an Account that conforms and
continues to conform to the following conditions:

                  A. The Account arose from a bona fide outright sale of Goods
         by the BORROWER or from services performed by the BORROWER, and such
         Goods have been shipped to the appropriate account debtors or their
         designees (or the sale has otherwise been consummated), or the services
         have been performed for the appropriate account debtors;

                  B. The Account is due and payable not more than 90 days from
         the date of the invoice therefor;


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                  C. If more than ten per cent (10%) of the invoices to a
         particular account debtor are ineligible, then all invoices to such
         account debtor shall become ineligible for borrowing purposes;

                  D. BORROWER has not received any notice of the filing of a
         petition in bankruptcy or insolvency laws by or against, the account
         debtor. Upon the receipt by the BORROWER of any such notice, it will
         immediately give the BANK written advice thereof;

                  E. The account debtor is not a subsidiary or other AFFILIATE
         of the BORROWER; and

                  F. The BANK has not deemed such account ineligible because of
         uncertainty about the credit worthiness of the account debtor or
         because the BANK otherwise reasonably considers the collateral value
         thereof to the BANK to be impaired or its ability to realize such value
         to be insecure.

In the event of any dispute, under the foregoing criteria, about whether an
Account is or has ceased to be an ELIGIBLE ACCOUNT the decision of the BANK
shall control.

         10. "EVENT OF DEFAULT" has the meaning provided for in Section VII.

         11. "FINANCIAL STATEMENTS" means the balance sheet of the BORROWER as
of December 31, 1999, and 1998, and statements of income, stockholders' equity,
and statement of cash flow, and notes thereto, of the BORROWER for the years or,
as appropriate, month ended on such dates as audited by independent certified
public accountants of recognized standing to present fairly the consolidated
financial position and results of operations of the BORROWER at such dates and
for such periods in accordance with GAAP.

         12. "GAAP" means generally accepted accounting principles applied
consistently as was done in the preparation of the FINANCIAL STATEMENTS with
such changes or modifications hereto as may be approved in writing by the BANK.

         13. "INDEBTEDNESS" means, as to the BORROWER, all items of
indebtedness, obligation or liability, whether matured or unmatured, liquidated
or unliquidated, direct or contingent, joint or several.

         14. "LOAN TERMINATION DATE" means the earliest to occur of the
following: (i) July 31, 2000, (ii) the date the obligations are accelerated
pursuant to this AGREEMENT, and (iii) the date BANK receives (a) notice in




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writing from BORROWER of BORROWER's election to terminate this AGREEMENT and (b)
indefeasible payment in full of the OBLIGATIONS, or such other date as may later
be agreed to by BANK and BORROWER in a written amendment to this AGREEMENT.

         15. "OBLIGATIONS" means the obligation of the BORROWER:

                  A. To pay the principal of, and interest on, any promissory
         note in accordance with the terms thereof and to satisfy all of its
         other liabilities to the BANK, whether hereunder or otherwise, whether
         now existing or hereafter incurred, matured or unmatured, direct or
         contingent, joint or several, including any extensions, modifications,
         renewals thereof, and substitutions therefor and including, but not
         limited to, any obligations under letter of credit agreements;

                  B. To repay to the BANK all amounts advanced by the BANK
         hereunder or otherwise on behalf of the BORROWER, including, but
         without limitation, advances for principal or interest payments to
         prior secured parties, mortgagees, or licensors, or taxes, levies,
         insurance, rent, or repairs to, or maintenance or storage of, any of
         the COLLATERAL; and

                  C. To reimburse the BANK, on demand, for all of the BANK's
         expenses and costs, including the reasonable fees and expenses of its
         counsel, in connection with the preparation, administration, amendment,
         modification, or enforcement of this AGREEMENT and the documents
         required hereunder, including, without limitation, any proceeding
         brought or threatened, to enforce payment of any of the OBLIGATIONS
         referred to in the foregoing Paragraphs A and B.

         16. "PERMITTED LIENS" means:

                  A. Liens for taxes, assessments, or similar charges, incurred
         in the ordinary course of business that are not yet delinquent;

                  B. Pledges or deposits made in the ordinary course of business
         to secure payment of workers' compensation, or to participate in any
         fund in connection with workers' compensation, unemployment insurance,
         old-age pensions or other social security programs;

                  C. Liens of mechanics, materialmen, warehousemen, carriers, or
         other like liens, securing obligations incurred in the ordinary course
         of business that are not yet due and payable;

                  D. Liens in favor of the BANK; and


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<PAGE>

                  E. Liens in favor of Security National Bank, Omaha, Nebraska,
         as evidenced by Nebraska Sec. of State financing statement #709241
         covering all equipment and fixtures of BORROWER, to the extent that
         such lien encumbers only those items as described on the attachment
         filed with the financing statement #709241.

         17. "PERSON" means any individual, corporation, partnership,
association, joint-stock company, trust, unincorporated organization, joint
venture, court, or government or political subdivision or agency thereof.

         18. "SUBORDINATED NOTES" means the BORROWER's promissory notes dated
March 24, 1999, in the original aggregate principal amount of $12,000,000,
denominated as "Convertible Notes".

Section II.  REVOLVING CREDIT FACILITY.

         1. REVOLVING CREDIT FACILITY. BANK agrees to lend $5,000,000.00 to
BORROWER pursuant to this facility. BANK will credit proceeds of this REVOLVING
CREDIT FACILITY to BORROWER's deposit account with the BANK, bearing number
11225078.

                  A. Subject to the terms hereof the BANK will lend the
         BORROWER, from time to time until the LOAN TERMINATION DATE such sums
         in integral multiples of $1,000 as the BORROWER may request by
         reasonable same day notice to BANK, received by the BANK not later than
         11:00 A.M. of such day, but which shall not exceed in the aggregate
         principal amount at any one time outstanding, $5,000,000.00 (the "LOAN
         COMMITMENT"). The BORROWER may borrow, repay without penalty or premium
         and reborrow hereunder, from the date of this AGREEMENT until the LOAN
         TERMINATION DATE, either the full amount of the LOAN COMMITMENT or any
         lesser sum. It is the intention of the parties that the outstanding
         principal amount of the REVOLVING CREDIT FACILITY shall at no time
         exceed the amount of the then existing BORROWING BASE and if, at any
         time, an excess shall for any reasons exist, the full amount of such
         excess, together with accrued and unpaid interest thereon as herein
         provided, shall be immediately due and payable in full.

                  B. THE NOTE. The LOAN COMMITMENT shall be evidenced by a
         promissory note ("NOTE") having stated maturity on the LOAN TERMINATION
         DATE, in the form attached hereto as Exhibit B. The NOTE shall specify
         the manner of principal and interest payments and rate of interest
         accrual.


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<PAGE>

         2. PAYMENT TO THE BANK AND COLLECTIONS.

                  A. All outstanding principal and unrepaid interest shall be
         due and payable on LOAN TERMINATION DATE, unless earlier paid or due as
         the result of acceleration.

                  B. COLLECTION OF ACCOUNTS

                           1. BANK shall have the rights at any time or times
                  hereafter all the rights of a secured creditor holding a
                  valid, and indefeasibly perfected security interest in
                  accounts pursuant to the Nebraska Uniform Commercial Code, as
                  well as the rights conferred by the COLLATERAL DOCUMENTS.

                           2. BORROWER hereby authorizes BANK to endorse, in the
                  name BORROWER, any item, howsoever received by BANK
                  representing payment on or other proceeds of any of the
                  COLLATERAL.

                           3. For purposes of determining the amount of the
                  OBLIGATIONS, including, without limitation, the computations
                  of interest which may from time to time be owing by BORROWER
                  to BANK, the receipt of any check or other item of payment by
                  BANK shall not be treated as a payment on account of the
                  liabilities until such check or other item of payment is
                  actually paid in cash or cash equivalent.

Section III.  CONDITIONS PRECEDENT.

         The obligations of the BANK to make the REVOLVING CREDIT FACILITY is
subject to the following conditions precedent:

          1. DOCUMENTS REQUIRED FOR THE CLOSING. The BORROWER shall have
delivered to the BANK, prior to the initial disbursement of the funds (the
"CLOSING"), the following:

                  A. The COLLATERAL DOCUMENTS, and the FINANCIAL STATEMENTS,
         duly executed by the BORROWER.

                  B. A copy, certified as of the date of the CLOSING, of the
         by-laws of the BORROWER.

                  C. A copy of all amendments to the articles of incorporation
         subsequent to June 27, 1997, certified as of the most recent date
         practicable by the Secretary of State of Delaware, together with a



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         certificate (dated the date of CLOSING) of the corporate secretary of
         the BORROWER to the effect that these are all the amendments to such
         articles of incorporation, together with a certificate of good
         standing.

                  D. A certificate, dated the date of the CLOSING, signed by the
         president or a vice president of the BORROWER and to the effect that:

                           1. The representations and warranties set forth in
                  Section V.1. are true as of the date of the CLOSING; and

                           2. No EVENT OF DEFAULT hereunder, and no event which,
                  with the giving of notice or passage of time or both, would
                  become such an EVENT OF DEFAULT, has occurred as of such date;

                  E. A duly executed BORROWING BASE CERTIFICATE as of a date not
         more than one (1) day prior to the CLOSING, acceptable to the BANK.

                  F. An assignment of the General American life insurance policy
         number 3949515, in form satisfactory to BANK, which policy insures the
         life of Colin D'Silva in an amount no less than $4,000,000.

         2. CERTAIN EVENTS. At the time of, and as a condition to, the CLOSING
and each disbursement of any part of the REVOLVING LOAN to be made by the BANK
at or subsequent to the CLOSING:

                  A. No EVENT OF DEFAULT shall have occurred and be continuing,
         and no event shall have occurred and be continuing that, with the
         giving of notice or passage of time or both, would be an EVENT OF
         DEFAULT;

                  B. No material adverse change shall have occurred in the
         business prospects, financial condition, or results of operations of
         the BORROWER since the dates of the FINANCIAL STATEMENTS; and

                  C. All of the COLLATERAL DOCUMENTS shall have remained in full
         force and effect.

Section IV.  COLLATERAL SECURITY.

         1. BORROWER has executed a security agreement, granting a security
interest in and to certain property ("COLLATERAL") to BANK. Such separate
security agreement is a COLLATERAL DOCUMENT.


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<PAGE>

Section V.   REPRESENTATIONS AND WARRANTIES.

         1. ORIGINAL. To induce the BANK to enter into this AGREEMENT, the
BORROWER represents and warrants to the BANK as follows:

                  A. The BORROWER has no subsidiaries, except for Transgenomic
         Ltd. in the United Kingdom, CETAC-Scientific Instruments B.V. in the
         Netherlands, and Transgenomic St. Thomas Inc. in the USVI (a foreign
         sales corporation) (collectively the "SUBSIDIARIES");

                  B. The BORROWER is not in default with respect to any of its
         existing INDEBTEDNESS, and the making and performance of this agreement
         and the COLLATERAL DOCUMENTS will not (immediately or with the passage
         of time, the giving of notice, or both):

                           1. Violate the articles of incorporation or by-laws
                  of the BORROWER, or violate any laws or result in a default
                  under any contract, agreement, or instrument to which the
                  BORROWER is a party or by which the BORROWER or its property
                  is bound; or

                           2. Result in the creation or imposition of any
                  security interest in, or lien or encumbrance upon, any of the
                  assets of the BORROWER except in favor of the BANK;

                  C. This agreement and the COLLATERAL DOCUMENTS are, or when
         delivered will be, valid, binding, and enforceable in accordance with
         their respective terms;

                  D. There is no pending order, notice, claim, litigation,
         proceeding, or litigation against or affecting the BORROWER, whether or
         not covered by insurance, that would materially or adversely affect the
         financial condition or business prospects of the BORROWER if adversely
         determined;

                  E. The FINANCIAL STATEMENTS, including any schedules and notes
         pertaining thereto, have been prepared in accordance with GAAP, and
         fully and fairly present the financial condition of the BORROWER at the
         dates thereof and the results of operations for the periods covered
         thereby, and there have been no material adverse changes in the
         consolidated financial condition or business of the BORROWER from
         December 31, 1999, to the date hereof;

                  F. As of the date hereof the BORROWER has no material
         INDEBTEDNESS of any nature, including but without limitation,
         liabilities for taxes and any interest or penalties relating thereto
         except to



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<PAGE>

         the extent reflected (in a footnote or otherwise) in the FINANCIAL
         STATEMENT or as disclosed in, or permitted by, this agreement; and the
         BORROWER does not know or have reasonable ground to know of any basis
         for the assertion against it of any such INDEBTEDNESS as of the date of
         the CLOSING;

                  G. No representation or warranty by or with respect to the
         BORROWER contained herein or in any certificate or other document
         furnished by the BORROWER pursuant hereto contains any untrue statement
         of a material fact or omits to state a material fact necessary to make
         such representation or warranty not misleading in light of the
         circumstances under which it was made;

                  H. Any federal tax returns for all years of operation,
         including the last tax year for BORROWER have been, or will be, filed
         by October 15, 2000, with the Internal Revenue Service and have not
         been challenged;

                  I. Any Employee Pension Benefit Plans, as defined in the
         Employee Retirement Income Security Act of 1974, as amended ("ERISA"),
         of the BORROWER meet, as of the date hereof, the minimum funding
         standards of 29 U.S.C. Sec. 1082 (Sec. 302 of ERISA), and no Reportable
         Event or Prohibited Transaction as defined in ERISA, has occurred with
         respect to any Employee Benefit Plans, as defined in ERISA, of the
         BORROWER;

                  J. BORROWER warrants (and this shall be a continuing warranty
         which shall survive until all the OBLIGATIONS of BORROWER to BANK have
         been fully satisfied) that it is in compliance with all federal, state
         and local environmental laws and regulations and has obtained all
         environmental permits necessary or appropriate to the conduct of its
         business. There is not pending nor, to the best of the BORROWER's
         knowledge after due inquiry, are there any threatened environmental
         enforcement actions, suits or proceedings before any court, tribunal or
         administrative body or official. Responsible officers and agents of the
         BORROWER have made an extensive investigation and have determined that
         the BORROWER has not, nor has any former owner of real property
         occupied by BORROWER stored, used or disposed of any toxic or hazardous
         substance on its properties or transported any such substance to or
         from its properties in violation of any presently existing or
         previously existing laws, regulations or policies. The BORROWER will
         store, use or dispose of such substances on its properties in
         accordance with presently existing or previously existing laws,
         regulations or policies.


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         2. SURVIVAL. All of the representations and warranties set forth in
Section V.1. shall survive until all OBLIGATIONS are satisfied in full and there
remain no outstanding commitments hereunder.

Section VI. COVENANTS OF THE BORROWER.

         1. AFFIRMATIVE COVENANTS. The BORROWER does hereby covenant and agree
with the BANK that, so long as any of the OBLIGATIONS remain unsatisfied or any
commitments hereunder remain outstanding, it will comply at all times with the
following covenants:

                  A. The BORROWER will furnish the BANK:

                           1. Within thirty (30) days after the close of each
                  monthly accounting period in each fiscal year an income
                  statement and balance sheet of the BORROWER for such month in
                  reasonable detail, subject to normal year-end audit
                  adjustments and certified by the BORROWER's president or
                  principal financial officer to have been prepared in
                  accordance with GAAP;

                           2. Within thirty (30) days after the end of each
                  calendar month, in such form and detail as shall be
                  satisfactory to the BANK, an aging, as of the end of such
                  month, of (a) the then ELIGIBLE ACCOUNTS, and (b) all other
                  Accounts of the BORROWER, certified by the president or chief
                  financial officer of the BORROWER to be complete and correct;

                           3. Each month (and at any additional time in the
                  discretion of the BANK or if any material deterioration in the
                  BORROWING BASE would be disclosed thereby) a BORROWING BASE
                  CERTIFICATE as of the end of such period. Each BORROWING BASE
                  CERTIFICATE shall be effective only as accepted by the BANK
                  (and with such revisions, if any, as the BANK may require as a
                  condition to such acceptance);

                           4. Within ninety (90) days after the close of each
                  fiscal year, income statements, balance sheets and statement
                  of cash flow of the BORROWER, for such fiscal year. These
                  reports are to be audited by independent certified public
                  accountant of recognized standing to present fairly the
                  consolidated financial position and results of operations of
                  the BORROWER in accordance with GAAP; and accompanied by such
                  accountants' opinion thereof that such documents have been
                  audited in compliance with the American Institute of Certified
                  Public Accountants Statements of Auditing Standards in effect
                  as of the



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<PAGE>

                  execution hereof; such accountants' opinion and certification
                  shall be directed to the BANK, providing that the client
                  representation of the accountants extends to BANK;

                  B. The BORROWER will maintain:

                           1. A BORROWING BASE such that the amount of the
                  BORROWER'S outstanding REVOLVING CREDIT FACILITY will not, at
                  any time, exceed its BORROWING BASE;

                           2. A minimum Tangible Net Worth of $6,000,000 as of
                  December 31, 1999, and at the end of each subsequent calendar
                  quarter. (For purposes of the calculation of this ratio,
                  SUBORDINATED NOTES should be added to Tangible Net Worth);

                           3. A minimum Net Working Capital of $3,000,000 as of
                  December 31, 1999, and at the end of each subsequent calendar
                  quarter;

                           4. A maximum ratio of "Total Liabilities/Tangible Net
                  Worth" of 1.5:1.0, as of December 31, 1999, and at the end of
                  each subsequent calendar quarter. (For purposes of the
                  calculation of this ratio, SUBORDINATED NOTES should be
                  deducted from Total Liabilities and added to Tangible Net
                  Worth).

                  For purposes of this agreement, Current Assets and Current
         Liabilities, mean, at any time, all assets or liabilities,
         respectively, that should, in accordance with GAAP, be classified as
         current assets or current liabilities, respectively, or be classified
         as a liability on a balance sheet of BORROWER. Net Working Capital
         means, at any time, the amount by which Current Assets exceed Current
         Liabilities. Total Liabilities mean all liabilities, which should, in
         accordance with GAAP, be classified as a liability. Tangible Net Worth
         means, at any time, Stockholders' Equity (the par value of outstanding
         capital stock, plus capital surplus, plus retained earnings, plus the
         principal balance of the SUBORDINATED NOTES, plus any amount reflecting
         cost of patents and proprietary software) less the sum of:

                           a. Any surplus resulting from any write up of assets
                  subsequent to December 31, 1998;

                           b. Goodwill, including any amounts, however
                  designated on a balance sheet of the BORROWER, representing
                  the excess of the purchase price paid for assets or stock
                  acquired over the value assigned thereto on the books of the
                  BORROWER;


                                       11
<PAGE>

                           c. Any amount at which shares of capital stock of the
                  BORROWER appear as an asset on the BORROWER'S balance sheet;

                           d. Loans and advances to stockholders, directors,
                  officers, or AFFILIATES;

                           e. Deferred taxes and deferred expenses;

                           f. Any amount reflecting value of trademarks, trade
                  names, and copyrights; and

                           g. Any other amount in respect of an intangible that
                  should be classified as an asset on a balance sheet of the
                  BORROWER in accordance with GAAP except for the cost of
                  patents and proprietary software, which are included in
                  Tangible Net Worth as indicated above.

                  C. The BORROWER will take all necessary steps to preserve its
         corporate existence and franchises and comply with all present and
         future laws applicable to it in the operation of its business, and all
         material agreements to which it is subject.

                  D. The BORROWER will give immediate notice to the BANK of (1)
         any litigation or proceeding in which it is a party if an adverse
         decision therein would require it to pay more than $10,000.00 or
         deliver assets the value of which exceeds such sum (whether or not the
         claim is considered to be covered by insurance); and (2) the
         institution of any other suit or proceeding involving it that might
         materially and adversely affect its operations, financial condition,
         property, or business prospects.

                  E. The BORROWER will pay when due all of its INDEBTEDNESS due
         third persons except when the amount thereof is being contested in good
         faith by appropriate proceedings and with adequate reserves therefor
         being set aside on its books.

                  F. The BORROWER will notify the BANK immediately 1) if it
         becomes aware of the occurrence of any EVENT OF DEFAULT or of any fact,
         condition, or event that only with the giving of notice or passage of
         time or both, could become an EVENT OF DEFAULT; 2) if it becomes aware
         of any material adverse change in the business prospects, financial
         condition (including, without limitation, proceedings in bankruptcy,
         insolvency, or reorganization), or results of operations of the
         BORROWER, or 3) upon the failure of the BORROWER to observe any of



                                       12
<PAGE>

         its respective undertakings hereunder or under the COLLATERAL
         DOCUMENTS.

                  G. The BORROWER will (1) fund any of its Employee Pension
         Benefit Plans in accordance with no less than the minimum funding
         standards of 29 U.S.C. Sec. 1082 (Section 302 of ERISA); (2) furnish
         the BANK, promptly after the filing of the same, with copies of any
         reports or other statements filed with the United States Department of
         Labor or the Internal Revenue Service with respect to any such Plan;
         and (3) promptly advise the BANK of the occurrence of any Reportable
         Event or Prohibited Transaction with respect to any Employee Benefit
         Plan.

                  H. BORROWER shall retain the services of Collin D'Silva as its
         Chairman of the Board and CEO.

                  I. The BORROWER shall furnish BANK an opinion of counsel, in
         form and substance satisfactory to BANK, opining that the execution
         and delivery of the AGREEMENT, as hereby amended, does not conflict
         with any provisions of the SUBORDINATED NOTES, the charter or bylaws
         of the BORROWER, or of any applicable LAWS, or any other agreement
         binding the BORROWER or its property of which, after reasonable
         inquiry, such counsel has knowledge.

                  J. BORROWER has negotiated a sale of its scientific instrument
         business to a former officer of BORROWER, or his nominee. The proceeds
         of that sale will include no less than $5,000,000 in cash paid to
         BORROWER. BORROWER agrees that the said proceeds will be either
         utilized as working capital by BORROWER; paid to BANK to reduce the
         principal balance of the OBLIGATIONS; or paid to reduce the loans due
         to Security National Bank in an amount no greater than that listed on
         the draft of the Audited Financial Statement dated 12-31-1999 plus
         accrued interest. BORROWER agrees that no portion of the said proceeds
         shall be paid on account of any other security interest or lien on
         assets of BORROWER other than the OBLIGATIONS, nor paid to any
         Stockholder of BORROWER or holder of any debentures issued by
         BORROWER, without BANK'S written approval.

         2. NEGATIVE COVENANTS. The BORROWER does hereby covenant and agree with
the BANK that, so long as any of the OBLIGATIONS remain unsatisfied or any
commitments hereunder remain outstanding, it will comply at all times with the
following negative covenants, unless the BANK shall otherwise have agreed in
writing, which agreement will not be unreasonably withheld:

                  A. The BORROWER shall not change its name, enter into any
         merger, consolidation, reorganization or recapitalization, or
         reclassify its capital stock;


                                       13
<PAGE>

                  B. BORROWER will not mortgage, pledge, grant, or permit to
         exist a security interest in, or a lien upon, any of its assets of any
         kind, now owned or hereafter acquired, except for liens in favor of
         BANK, or PERMITTED LIENS, or liens subordinate and junior to the lien
         of the BANK;

                  C. BORROWER will not become liable, directly or indirectly, as
         Guarantor or otherwise for any OBLIGATION of any other person;

                  D. BORROWER will not declare or pay any dividends, or make any
         other payment or distribution on account of its capital stock; nor make
         any assignment or transfer of Accounts, or, other than in the ordinary
         course of business, of Inventory;

                  E. BORROWER will form no subsidiary, make no investment in
         (including any assignment of Inventory or other property), or make any
         loan in the nature of an investment to, any person;

                  F. BORROWER will not make any loan or advance to any officer,
         shareholder, director, or employee of the BORROWER, except for business
         travel and similar temporary advances in the ordinary course of
         business;

                  G. BORROWER will not redeem, purchase, or retire any of its
         capital stock, or purchase or retire for any consideration, any
         warrant, right or option pertaining thereto, or permit any redemption,
         retirement, or other acquisition by BORROWER of the ownership of the
         outstanding capital stock of the BORROWER;

                  H. BORROWER shall not furnish the BANK any certificate or
         other document that will contain any untrue statement of material fact
         or that will omit to state a material fact necessary to make it not
         misleading in light of the circumstances under which it was furnished;
         and

                  I. BORROWER will not directly or indirectly apply any part of
         the proceeds of the OBLIGATIONS to the purchasing or carrying of any
         "margin stock" within the meaning of Regulation U of the Board of
         Governors of the Federal Reserve System, or any regulations,
         interpretations, or rulings thereunder.

                  J. BORROWER will not make any prepayments of principal or
         interest on the SUBORDINATED NOTES, and in the EVENT OF DEFAULT under
         the AGREEMENT, the BORROWER will not make any



                                       14
<PAGE>

         further payments of principal or interest on the SUBORDINATED NOTES
         without prior consent of the BANK. BORROWER will not take any other
         actions that would result in these SUBORDINATED NOTES being or becoming
         superior in any manner to the OBLIGATIONS. BORROWER agrees not to give
         SUBORDINATED NOTES any security interest in the assets of the BORROWER
         without the permission of BANK.

Section VII.  DEFAULT.

         1. EVENTS OF DEFAULT. The occurrence of any one or more of the
following events shall constitute an EVENT OF DEFAULT hereunder:

                  A. The BORROWER shall fail to perform any covenant, promise,
         or payment obligation made in this AGREEMENT or any COLLATERAL
         DOCUMENTS;

                  B. Any financial statement, representation, warranty, or
         certificate made or furnished by or with respect to the BORROWER to the
         BANK in connection with this AGREEMENT, or as an inducement to the BANK
         to enter into this AGREEMENT, or in any separate statement or document
         to be delivered to the BANK hereunder, shall be materially false,
         incorrect, or incomplete when made.

         2. ACCELERATION. At the option of the BANK upon the occurrence of any
EVENT OF DEFAULT, all OBLIGATIONS, whether hereunder or otherwise, shall
immediately become due and payable.

         3. REMEDIES. After any acceleration, as provided for in Section VII.
2., the BANK shall have, in addition to the rights and remedies given it by this
AGREEMENT and the COLLATERAL DOCUMENTS, all those allowed by all applicable
laws, including, but without limitation, the Uniform Commercial Code as enacted
in any jurisdiction in which any COLLATERAL may be located. The rights of the
BANK under this Section VII.3. are in addition to the other rights and remedies
(including, without limitation, other rights of set-off) which the BANK may
have.

Section VIII.  MISCELLANEOUS.

         1. CONSTRUCTION. Nothing herein contained shall prevent the BANK from
enforcing any or all other guaranty, pledge or security agreements, notes,
mortgages, deeds of trust, other evidences of liability, or other COLLATERAL
DOCUMENTS in accordance with their respective terms.

         2. ENFORCEMENT AND WAIVER BY THE BANK. The BANK shall have the right at
all times to enforce the provisions of this agreement and the



                                       15
<PAGE>

COLLATERAL DOCUMENTS in strict accordance with the terms hereof and thereof,
notwithstanding any conduct or custom on the part of the BANK in refraining from
so doing at any time or times to enforce its rights under such provisions,
strictly in accordance with the same, shall not be construed as having created a
custom in any way or manner contrary to specific provisions of this AGREEMENT or
as having in any way or manner modified or waived the same. All rights and
remedies of the BANK are cumulative and concurrent and the exercise of one right
or remedy shall not be deemed a waiver or release of any other right or remedy.

         3. RENEWAL. On the existing LOAN TERMINATION DATE, all of the
OBLIGATIONS become due, and the BANK's commitment to lend shall terminate.
BORROWER may request an amendment of the LOAN TERMINATION DATE and a renewal, in
some form, of the commitment. BANK agrees to consider such request when made,
using as a basis for its decision all of the FINANCIAL STATEMENTS furnished by
BORROWER, together with any other information available to BANK. BANK may make
such renewal or amendment if, in BANK's sole discretion, such renewal or
amendment is warranted in the exercise of sound banking practices.

         4. EXPENSE OF THE BANK. The BORROWER will, on demand, reimburse the
BANK for all expenses, including the reasonable fees and expenses of legal
counsel for the BANK, incurred by the BANK in connection with the preparation,
administration, amendment, modification, or enforcement of this AGREEMENT, the
COLLATERAL DOCUMENTS, and the collection or attempted collection of the
OBLIGATIONS.

         5. NOTICES. Any notice or consents required or permitted by this
AGREEMENT shall be in writing and shall be deemed delivered if delivered in
person or if sent by certified mail, postage prepaid, return receipt requested,
or telegraph, as follows, unless such address is changed by written notice
hereunder:

            A. If to the BORROWER:          Transgenomic, Inc.
                                            5600 South 42nd Street
                                            Omaha, Nebraska 68107
                                            Attn:  Collin D'Silva

            B. If to the BANK:              First National Bank of Omaha
                                            One First National Center
                                            Omaha, Nebraska 68102
                                            ATTN: Mark McMillan

         6. WAIVER AND RELEASE BY THE BORROWER. To the maximum extent permitted
by applicable laws, the BORROWER:


                                       16
<PAGE>

                  A. Waives notice of acceleration and of intention to
         accelerate; and notice and opportunity to be heard, after acceleration
         in the manner provided in Section VII, before exercise by the BANK of
         the remedies of self-help, set-off, or of other summary procedures
         permitted by any applicable laws or by any agreement with the BORROWER,
         and, except where required hereby or by any applicable law, notice of
         any other action taken by the BANK; and

                  B. Releases the BANK and its officers, attorneys, agents, and
         employees from all claims for loss or damage caused by any act or
         omission on the part of any of them except willful misconduct or gross
         negligence.

         7. APPLICABLE LAW. This AGREEMENT is entered into and performable in
Omaha, Douglas County, Nebraska, and shall be subject to and construed and
enforced in accordance with the laws of the State of Nebraska.

         8. BINDING EFFECT, ASSIGNMENT, AND ENTIRE AGREEMENT. This AGREEMENT
shall inure to the benefit of, and shall be binding upon, the respective
successors and permitted assigns of the parties hereto. The BORROWER has no
right to assign any of its rights or OBLIGATIONS hereunder without the prior
written consent of the BANK. This AGREEMENT, including the Exhibits hereto, all
of which are hereby incorporated herein by reference, and the documents executed
and delivered pursuant hereto, constitute the entire agreement between the
parties and may be amended only by a writing signed on behalf of each party.

         9. SEVERABILITY. If any provision of this AGREEMENT shall be held
invalid under any applicable law, such invalidity shall not affect any other
provision of this AGREEMENT that can be given effect without the invalid
provision, and, to this end, the provisions hereof are severable.

         IN WITNESS WHEREOF, the parties hereto have duly executed this
AGREEMENT as of the day and year first above written.

                                               TRANSGENOMIC, INC.

                                               By: /s/ Collin J. D'Silva
                                                   -------------------------
                                               Title: Chief Executive Officer
                                                      ----------------------

                                               FIRST NATIONAL BANK OF OMAHA

                                               By: /s/ Mark McMillan
                                                   -------------------------
                                               Title: Second Vice President
                                                      ----------------------


                                       17
<PAGE>

Exhibit A - Borrowing Base Certificate
Exhibit B - Promissory Note



                                       18
<PAGE>


                                    EXHIBIT A



                                       19
<PAGE>

                                    EXHIBIT B

                                 PROMISSORY NOTE

[LOGO]

                               Transgenomic, Inc.
                                5600 So. 42nd St.
                                 Omaha, NE 68107

<TABLE>

<S>                  <C>              <C>           <C>             <C>             <C>
Principal Amount     Interest Rate    Note Date     Maturity Date   Obligor #       Note #
$5,000,000.00        Variable         07/31/99      07/31/00        2000046172      1
                     NAT Base



</TABLE>

Maker promises to pay to the order of First National Bank of Omaha ("Bank") at
any of its offices, the principal sum hereof, which shall be: (Revolving) the
lesser of FIVE MILLION AND NO/100 Dollars or so much thereof as may have been
advanced by Bank. The Maker may borrow, repay without penalty, and reborrow from
Note Date until Maturity Date, either the full amount of this loan or any lesser
sum.

Interest shall accrue on the outstanding principal amount from and including the
Note Date above to the Maturity Date at the rate of: The rate in effect from
time to time and designated by Bank as its National Base Rate ("Base Rate").

Interest shall be computed on the basis of actual days elapsed and a year of 360
days. The unpaid principal and interest due on this Note at maturity (whether
the Note matures by demand, acceleration, lapse of time or otherwise) shall bear
interest at the lesser of 6% per annum above the interest rate stated above, or
the highest rate allowed by law.

Principal and interest shall be paid as follows: Principal due on Maturity Date,
interest due MONTHLY beginning AUGUST 31, 1999 and on the same day of each MONTH
thereafter.

Related Documents: Maker has signed the following documents in connection with
this Note: Security Agreement(s) dated 09/17/97 covering all business assets.

Assignment(s) of Collateral dated July 31, 1999 covering life insurance policy.

Loan Agreement dated 09/17/97 and all amendments thereof.

A credit agreement must be in writing to be enforceable under Nebraska law. To
protect you and us from any misunderstandings or disappointments, any contract,
promise, undertaking, or offer to forebear repayment of money or to make any
other financial accommodation in connection with this loan of money or grant or
extension of credit, or any amendment of, cancellation of, waiver of, or
substitution for any or all of the terms or provisions of any instrument or
document executed in connection with this loan of money or grant or extension of
credit, must be writing to be effective.

Witnessed By:               Transgenomic, Inc.

/s/ Mark McMillan           By:  /s/ Stephen F. Dwyer           Title:  V.C.
---------------------            ------------------------             ---------


                                       20
<PAGE>


                              TERMS AND CONDITIONS

1.       Maker shall reimburse Bank for all expenses incurred in protecting or
         enforcing its rights. Maker's liability under its Obligations ("all
         Maker's existing and future obligations of whatever nature and whenever
         incurred to Bank") shall not be affected by any of the following:

         -        Acceptance or retention by Bank of other property or interests
                  as security for the Obligations, or for the liability of any
                  person other than a Maker with respect to the Obligations;

         -        Any release, extension, renewal, modification or compromise of
                  any of the Obligations or the liability of any obligor
                  thereon; or

         -        Failure by Bank to resort to other security or any person
                  liable for the Obligations.

         Each maker specifically consents to multiple renewals or extensions of
         the Obligations. This Note shall be deemed extended through the date of
         any advance made by Bank after the original maturity hereof; and any
         such advance shall constitute principal due under this Note.

2.       REPRESENTATION, WARRANTIES AND COVENANTS. Each Maker represents,
         warrants and covenants as follows:
         This Note, security agreement, deed of trust, mortgage, or other lien
         documents(s), if any, securing the Note have been duly authorized,
         executed and delivered by the Maker and constitute legal, valid and
         binding Obligations of Maker.
         This Note evidences a loan for business or agricultural purposes.
         Maker will provide business reports and with such frequency as Bank
         shall request; and
         Maker agrees to pay all costs of collection in connection with this
         Note, including reasonable attorneys' fees and legal expenses.

3.       DEFAULTS AND REMEDIES. Upon the occurrence of one of more of the
         following events of default:

         -        Maker fails to pay when due any of the Obligations, or to
                  perform or rectify breach of, any warranty or other
                  undertaking by Maker in this Note or the other Obligations; or
                  breaches any other covenant or condition described in any
                  other document;

         -        Any Maker, endorser, surety, or guarantor of any of the
                  Obligations dies, ceases to exist, makes an assignment for the
                  benefit of creditors, becomes insolvent or the subject of
                  bankruptcy or insolvency proceedings;

         -        Any representation made to induce Bank to extend credit under
                  this Note or otherwise is false in any material respect when
                  made;

         -        A material adverse change, in the opinion of Bank, occurs in
                  the financial or business condition of any Maker or of any
                  endorser, surety or guarantor of this Note;

         -        The entry of a judgment against any Maker;

         -        Filling of any lien against any Maker;

         -        The taking possession of any substantial part of the property
                  of any Maker at the instance of any governmental authority;

         -        The dissolution, merger, consolidation, or reorganization of
                  any Maker, or other entity liable for this Obligation;

         -        Any other event occurs which causes Bank in good faith to deem
                  itself insecure;

         then in such event, all of the Obligations shall, at the option of Bank
         and without notice or demand, mature and become immediately due and
         payable; and Bank shall have all rights and remedies for default
         provided by the Uniform Commercial Code, and any other applicable law
         and/or the Obligations.

         All costs and expenses incurred by Bank in enforcing its rights under
         this Note or any mortgage or other lien, endorsement, surety agreement,
         guarantee relating thereto are the obligations of Maker and are
         immediately due and payable. Interest shall accrue on such costs and
         expenses from the date of incurrence at the rate specified herein for
         delinquent Note payments. Each Maker, endorser, surety and guarantor
         hereby waives presentment, protest, demand, notice of dishonor, and the
         defense of any statute of limitations.


                                       21
<PAGE>

4.       GENERAL. Without affecting the liability of any Maker, endorser,
         surety, or guarantor, the holder may, without notice, renew or extend
         the time for payment, accept partial payments, release or impair any
         collateral security for the payment of this Note or agree to sue any
         party liable on it.

         Subject to rights afforded by law, Bank may at any time and for any
         reason, charge to or off-set against any amount then on deposit in any
         account (including a savings certificate), whether or not then due, any
         and all debts or liabilities (sole, several, joint, or joint and
         severable, absolute or contingent, due or not due, liquidated or
         unliquidated, secured or unsecured) then owed to Bank by depositor or
         in the case of a multiple-party account, by any party to such
         multiple-party account, and this agreement shall be construed to be the
         consent of depositor and any such party for the Bank to make such
         charge or off-set if consent be required by any person or future law.

         Bank shall not be deemed to have waived any of its rights upon or under
         this Note, or under any mortgage or other lien, endorsement, surety
         agreement, or guarantee unless such waivers be in writing and signed by
         Bank. No delay or omission on the part of Bank in exercising any right
         shall operate as a waiver of such right or any other right. A waiver on
         any one occasion shall note be construed as a bar to or waiver of any
         right on any future occasion. All rights and remedies of Bank on
         liabilities or the collateral whether evidenced hereby or by any other
         instrument or papers shall be cumulative and may be exercised
         singularly or concurrently.

         Maker, if more than one, shall be jointly and severally liable
         hereunder and all provisions hereof regarding the liabilities or
         security of Maker shall apply to any liability or any security of any
         or all of them. This agreement shall be binding upon the heirs,
         executors, administrators, assigns or successors of Maker; shall
         constitute a continuing agreement, applying to all future as well as
         existing transaction, whether or not of the character contemplated at
         the date of this Note, and if all transactions between Bank and Maker
         shall be at any time closed, shall be equally applicable to any new
         transactions thereafter; shall benefit Bank, its successors, and
         assigns; and shall so continue in force not withstanding any change in
         any partnership party hereto, whether such change occurs through death,
         retirement or otherwise.

         If any party of this Note is a married person, such person or persons
         hereby separately charges his or her separate estate, including both
         that now owned and that hereafter acquired, with the payment of this
         Note.

         This Note shall be construed according to the laws of the State of
         Nebraska. Unless the content otherwise requires, all terms used herein
         which are defined the Uniform Commercial Code shall have the meanings
         therein stated.

         Any provision of this Note which is prohibited or unenforceable in any
         jurisdiction shall, as to such jurisdiction, be ineffective to the
         extent of such prohibition or unenforceability without invalidating the
         remaining provisions hereof or affecting the validity or enforceability
         of such provision in any other jurisdiction.



                                       22