Abstract: A new antibiotic having .beta.-lactamase inhibitory activity, PA-39504-X.sub.1 of the formula: ##STR1## being useful as a medicament and a veterinary drug for inhibiting the growth of gram-positive and gram-negative pathogenic microorganisms and a process for preparing the same, being characterized by cultivating Streptomyces argenteolus PA-39504 or Streptomyces tokunonensis PA-31088 in a suitable medium and recovering PA-39504-X.sub.1 from the cultured broth.

Abstract: Penicillins and cephalosporins can be synthesized by the action of an acylase on a penicillin or cephalosporin nucleus amine as substrate and an ester (I) of the following formula as the acyl source: ##STR1## (wherein RCO is an acyl group in penicillin or cephalosporin side chains;X is a hydrogen atom, lower alkyl group or hydroxy-lower alkyl group;Y is a hydrogen atom or a lower alkyl group; and n is a positive integer).The novel acyl source (I) is also disclosed.

Abstract: A new antibiotic having .beta.-lactamase inhibitory activity, PA-31088-IV, being useful as a medicament and a veterinary drug for inhibiting the growth of gram-positive and gram-negative phathogenic microorganisms and a process for preparing the same, being characterized by cultivating Streptomyces tokunonensis sp. nov. in a suitable medium and recovering PA-31088-IV from the cultured broth.

Abstract: Penicillin or cephalosporin antibiotics represented by following formula: ##STR1## where ##STR2## is an acyl group derived from an .alpha.-amino acid, N-ammonium salt of .alpha.-amino acid, or N--(C.sub.1 to C.sub.10) acyl-.alpha.-amino acid; COOM is carboxy or carboxylate salt group!Are prepared by treating an amino compound selected from a group consisting of 6-aminopenicillanic acid, 7-aminocephalosporanic acid, 7-aminodeacetoxycephalosporanic acid, and their salts with an ester represented by following formula:RCOOR.sup.1where ##STR3## is as defined above and R.sup.1 is a (C.sub.1 to C.sub.10) alkyl group! BY ENZYMATIC ACYLATION EFFECTED WITH MYCELIUM OR MYCELIUM PREPARATION FROM A MICROORGANISM BELONGING TO GENUS Aphanocladium or Cephalosporium.

Abstract: The bond strength of composite articles of rubber adhered to ferrous metal substrates through an adhesive is substantially improved at ambient and elevated temperatures by using as the adhesive an interpolymer comprising a conjugated diene and a heterocyclic nitrogen base and containing about 5-180 parts of silica filler per 100 parts by weight of interpolymer. Further improvement is achieved by using a rubber containing about 0.025 to about 1.0 parts by weight of a cobalt compound, calculated as cobalt metal, per 100 parts of rubber.