425 1 0001.txt Filed by Dexter Corporation Pursuant to Rule 425 under the Securities Act of 1933 Subject Company: Dexter Corporation Commission File No. 001-05542 ------------------------------------------------------------------------------- Important Notice Regarding the SECOND SPECIAL MEETING ------ ------------------------------------------------------------------------------- of Dexter Corporation to be held September 14, 2000 [Dexter Corp. logo] September 1, 2000 Dear Shareholder: Your vote has not been received for the special merger meeting of shareholders of Dexter Corporation to be held at The University Club, One West 54th Street, New York, New York 10019 on Thursday, September 14, 2000, at 11:30 a.m., local time. PLEASE KEEP IN MIND THAT THIS IS THE SECOND DEXTER SPECIAL MEETING FOR WHICH YOU HAVE BEEN ASKED TO VOTE. AT THE FIRST SPECIAL MEETING ON WEDNESDAY, AUGUST 30, 2000, SHAREHOLDERS OVERWHELMINGLY APPROVED THE NONWOVENS ASSET SALE TO AHLSTROM PAPER GROUP OY FOR $275 MILLION IN CASH. PLEASE TAKE THE TIME RIGHT NOW TO ENSURE THAT YOUR VOTE IS CAST AT THIS SECOND IMPORTANT MEETING. At the meeting you will be asked to approve Dexter Corporation's merger with Invitrogen Corporation. In the merger, each outstanding share of Dexter common stock will be converted into $62.50 in cash or Invitrogen common stock or both. This proposal requires the affirmative vote of the holders of at least two-thirds of the voting power of all outstanding shares of Dexter common stock on the August 14, 2000 record date. YOUR BOARD OF DIRECTORS HAS UNANIMOUSLY APPROVED THE MERGER WITH INVITROGEN AND RECOMMENDS THAT DEXTER STOCKHOLDERS VOTE FOR THE MERGER PROPOSAL DESCRIBED IN THE MATERIALS PREVIOUSLY SENT TO YOU. Please vote by Telephone or Internet Today! REMEMBER - EVERY SHARE AND EVERY VOTE COUNTS! You may also sign, date and mail your duplicate proxy card in the envelope provided. If you have any questions, please call MacKenzie Partners, Inc at (800) 322-2885. Thank you in advance for voting promptly. Sincerely, K. Grahame Walker Chairman and Chief Executive Officer PLEASE TAKE A MOMENT TO VOTE YOUR SHARES TODAY! Investors and shareholders are advised to read the joint proxy statement and prospectus regarding Dexter Corporation's proposed merger with and into Invitrogen Corporation referenced in the foregoing information, because it contains important information. The joint proxy statement and prospectus was filed with the Securities and Exchange Commission by Invitrogen as part of Invitrogen's registration statement on form S-4, which became effective August 14, 2000. Investors and shareholders may obtain a free copy of the joint proxy statement and prospectus and other documents filed by Dexter or Invitrogen at the Securities and Exchange Commission's web site at http://www.sec.gov. The joint proxy statement and prospectus and such other documents also may be obtained by directing such request to Dexter Corporation, One Elm Street, Windsor Locks, Connecticut 06906, 860-292-7675.