Some coat protein constituents from strawberry latent ringspot virus expressed in transgenic tobacco protect plants against systematic invasion following root inoculation by nematode vectors

The coding sequences in RNA2 for the coat proteins (CP) of strawberry latent ringspot virus (SLRSV) were modified and amplified using polymerase chain amplification reactions (PCR) to facilitate their expression inAgrobacterium tumefaciens-transformedNicotiana tabacum Xanthi-nc. The coding sequences for the smaller capsid protein (S, 29kDa) and that for the theoretical precursor of L and S (P, 73kDa) had ATG initiation codon sequences added at the 5-proximal Ser/Gly (S/G) cleavage site in the unmodified sequence. The sequence coding for the larger of the two proteins of mature SLRSV capsids (L, 44kDa) had an ATG codon added at its 5 S/G site and a TAG stop codon sequence added at the 3-proximal S/G site. The P, L and S proteins were expressedin planta to a maximum concentration of 0.01 % of total extractable proteins but did not assemble into virus-like particles. When challenged by mechanical inoculation with virus particles or viral RNA, and compared with control plants, tobacco plants (primary transgenic clones or S1 and S2, kanamycin-resistant seedlings) expressing the virus capsid subunits separately, or their precursor, decreased the accumulation of SLRSV particles in inoculated leaves and fewer plants became invaded systemically. In experiments in which the roots of seedlings were exposed to SLRSV-carrying vector nematodes (Xiphinema diversicaudatum), SLRSV was detected in the roots of non-transformed control tobacco plants (6/20) and in transgenic tobacco expressing the L protein (7/40), but not in any of 25 tobacco plants expressing the S protein or in 35 expressing the P protein. This is the second example of CP-mediated resistance to virus inoculation by nematode vectors.     

Death of an African elephant from probable toxemia attributed to chronic pulpitis

A 31-year-old captive male African elephant (Loxodonta africana) of 5,000-kg body weight died suddenly in ventral recumbency. Lesions seen at necropsy were bilateral purulent pulpitis and periodontitis of both tusks, serous atrophy of coronary groove fat, Grammocephalus cholangitis, myocardial and skeletal lipofuscinosis, and scattered segmental necrosis in the pectoral muscles. Nonhemolytic streptococci, Corynebacterium sp, Peptostreptococcus anaerobius, Fusobacterium nucleatum, and Bacteroides sp, were recovered from the exudate around one or both tusks. We postulated that the elephant died of hypoxia from prolonged ventral recumbency because of weakness and inability to rise secondary to toxemia from bilateral pulpitis and periodontitis.     

Bacterial epididymitis in two stallions

Two stallions had unilateral bacterial epididymitis attributable to S zooepidemicus infection. Diagnosis was based on bacterial isolation, WBC in the semen, higher than normal blood fibrinogen concentration, and leukocytosis with regenerative left shift. One horse had high seminal pH. Ultrasonography of the involved epididymides revealed changes consistent with the appearance of abnormal accumulation of exudate in the tail of the epididymis. Treatment included unilateral orchiectomy and antibiotic administration. In stallion 1, the infection persisted despite treatment. Treatment result was not available for stallion 2.