Long W tracts are over-represented in the Escherichia coli and Haemophilus influenzae genomes.

The occurrence of DNA tracts of the three binary base combinations: R.Y, K.M and W;S has been mapped in the complete genomes of Haemophilus influenzae and Escherichia coli.

Expression of allogeneic MHC class I antigens by transgenic mouse trophoblast does not interfere with the normal course of pregnancy.

Mammalian embryos express paternal histocompatibility antigens which make them potential targets for maternal immune responses. Yet, the histoincompatible fetus survives and develops normally. Down regulation of classical MHC antigen expression by trophoblast cells which are in direct contact with maternal circulation has been repeatedly shown.

Seqalert--a daily sequence alertness server for the EMBL and SWISSPROT databases.

Motivation: The aims were to: enable users to deposit complex search profiles against the sequence databases; interface to an independent Sequence Retrieval System (SRS) server through the network to perform these searches on a daily basis through the last day's updates of these databases; mail users the reformatted search results, enabling local usage when loaded by a WWW browser.

Results: The deposition of one to many search profiles by the user leads to a daily search of the EMBL and SWISSPROT databases. The search profile is restricted to entries that were deposited during the last 24 h by using the SRS query manager to combine search sets.

EMBL sequence submission system--an object-oriented approach to developing interactive data collection systems through the WWW.

Motivation: To enable a new way of submitting sequence information to the EMBL nucleotide database through the WWW. This process of data submission is long and complex, and calls for efficient and user-friendly mechanisms for collection and validation of information.

Results: Described here is a generic, object-oriented data-submission system that is being used for the EMBL database, but can easily, be tailored to serve several data-submission schemes with a relatively short development and implementation time.