Dexter Signs Sale Agreement With Invitrogen Corporation

Shareholders to Receive $62.50 Per Share in Cash and Invitrogen Stock

Sale Marks Completion of Dexter Program to Maximize Shareholder Value
Through Merger of Life Technologies with Invitrogen

WINDSOR LOCKS, Conn., July 9, 2000 -- Dexter Corporation (NYSE: DEX) today
announced that it has signed a definitive agreement with Invitrogen
Corporation (Nasdaq: IVGN) providing for a merger of Dexter into Invitrogen
in which all Dexter outstanding shares will be converted into $62.50 per
share in cash and Invitrogen stock. This transaction follows Dexter's
previously announced agreements to sell its Electronic Materials, Adhesives
and Polymer Systems and Nonwoven Materials businesses and marks the
culmination of Dexter's program to maximize shareholder value in the short
term.

In addition to the Dexter merger, Invitrogen has also agreed to a merger
with Life Technologies, Inc. (OTC: LTEK) in which shares of Life
Technologies will be converted into $60 per share in cash and Invitrogen
stock. Dexter currently owns approximately 75 percent of Life Technologies'
stock.

The combination of Invitrogen and Life Technologies creates a leading
company in life sciences and genomics with annual revenues in excess of
$500 million and approximately $100 million in operating cash flow. The
transaction will make Invitrogen a premier products provider for molecular
biology research, particularly gene cloning, expression, and analysis --
key techniques in deciphering the human genome sequence, which was recently
completed.

Following the simultaneous mergers of Dexter into Invitrogen and Life
Technologies into Invitrogen, Dexter will have completed all phases of its
disposition program and shareholders will have received cash and shares of
Invitrogen worth $62.50 per Dexter share and $60.00 per Life Technologies
share.

As previously announced, Dexter has signed binding, definitive agreements
to sell its Electronic Materials, Adhesives and Polymer Systems businesses
to Loctite Corporation (a member of the Henkel Group) for $400 million in
cash and its Nonwoven Materials business to Ahlstrom Paper Group Oy for
$275 million in cash. The net after-tax proceeds from these two sales are
expected to be approximately $530 million, of which approximately $260
million will be used to repay debt. Completion of these asset sales is a
condition to the closing of the Invitrogen mergers. In addition, Dexter
will continue active discussions, in consultation with Invitrogen,
concerning a potential sale of its Coatings business, but this is not a
condition to the closing of the Invitrogen mergers.

K. Grahame Walker, Chairman and Chief Executive Officer of Dexter, said:
"The transaction with Invitrogen marks the completion of our program to
maximize shareholder value in the short term. We are pleased by the
significant value that has been generated for our shareholders and
heartened that all of the company's business operations will be in good
hands. We will now move forward aggressively to make the necessary
regulatory filings and close all these transactions as quickly as
possible."

Under the terms of the Dexter/Invitrogen merger, which has been unanimously
approved by the Boards of Directors of Dexter and Invitrogen, Dexter
shareholders will have the option to receive for each Dexter share: (i)
$62.50 in cash, subject to proration; (ii) $17.50 in cash and $45 in
Invitrogen stock; or (iii) $62.50 in Invitrogen stock. Approximately $410
million of cash (28 percent of the aggregate consideration) is available
for the Dexter shareholders. The price of the Invitrogen stock issued in
the transaction, which will be subject to a collar, will be based on the
average closing price during the 20 days ending on the third trading day
prior to the Dexter shareholder meeting to approve the transaction.

The collar provides a fixed value of stock consideration so long as
Invitrogen shares reflect an average trading price between $60 and $80 per
share. Below an average of $60, the ratio for each Dexter share will be
fixed at 1.0417 Invitrogen shares and above an average of $80, the ratio
for each Dexter share will be fixed at 0.7813 Invitrogen shares.

The transaction is subject to the Hart-Scott-Rodino Act and other customary
conditions, approval of the shareholders of Dexter (two-thirds of the
outstanding shares), Invitrogen (a majority of the outstanding shares) and
Life Technologies (67 percent of the outstanding shares), and closing of
Dexter's aforementioned asset sales. The transaction is expected to close
in the fall of 2000.

Dexter's financial advisor for this transaction is Lehman Brothers. Its
legal advisor is Skadden, Arps, Slate, Meagher & Flom LLP.

Invitrogen develops, manufactures and markets research tools in kit form
and provides other research products and services to corporate, academic
and government entities. These research kits simplify and improve gene
cloning, gene expression and gene analysis techniques and are used for
genomics and gene-based drug discovery, among other molecular biology
activities. Founded in 1987, Invitrogen is headquartered in San Diego,
California and also has operations in Huntsville, Alabama, Groningen,
Netherlands, and Heidelberg, Germany. For more information about
Invitrogen, visit the Invitrogen Website at www.invitrogen.com .

Dexter Corporation is a global specialty materials supplier with three
operating segments: life sciences, nonwovens, and specialty polymers. The
company supplies specialty materials to the aerospace, electronics, food
packaging, and medical markets.

Any statements in this press release that are not historical facts are
"forward-looking statements" as that term is defined under the Federal
Securities Laws. Forward- looking statements are subject to risks,
uncertainties and other factors, which could cause actual results to differ
materially from those stated in such statements. These and other risks are
detailed in the Company's filings with the Securities and Exchange
Commission (SEC).

ADDITIONAL INFORMATION

Information regarding the identity of the persons who may, under SEC rules,
be deemed to be participants in the solicitation of stockholders of Dexter,
Life Technologies and Invitrogen in connection with the proposed mergers,
and their interests in the solicitation, are set forth in a Schedule 14A
filed on the date of this press release with the SEC. Dexter, Life
Technologies and Invitrogen will be filing joint proxy
statements/prospectuses and other relevant documents concerning the
proposed transaction with the SEC. INVESTORS ARE URGED TO READ THE PROXY
STATEMENT/PROSPECTUS WHEN IT BECOMES AVAILABLE AND ANY OTHER RELEVANT
DOCUMENTS FILED WITH THE SEC BECAUSE THEY WILL CONTAIN IMPORTANT
INFORMATION ON THE PROPOSED TRANSACTION. Investors will be able to obtain
the documents free of charge at the SEC's website (www.sec.gov). In
addition, documents filed with the SEC by Dexter will be available free of
charge by contacting Dexter Corporation, One Elm Street, Windsor Locks,
Connecticut 06096, Attention: Investor Relations, (860) 292- 7675.
Documents filed with the SEC by Life Technologies will be available free of
charge by contacting Life Technologies, Inc., C. Eric Winzer, 9800 Medical
Center Drive, P.O. Box 6482, Rockville, Maryland 20850, (301) 610-8800.
Documents filed with the SEC by Invitrogen may be obtained free of charge
by contacting Invitrogen Corporation, Cheri Manis, 1600 Faraday Avenue,
Carlsbad, California, 92008, (760) 603-7200. INVESTORS SHOULD READ THE
PROXY STATEMENT/PROSPECTUS CAREFULLY WHEN IT BECOMES AVAILABLE BEFORE
MAKING ANY VOTING OR INVESTMENT DECISION REGARDING THE INVITROGEN
TRANSACTIONS.

                Special Materials for Special Effects