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Phenylalanine tRNA from the blue-green alga, Agmenellum quadruplicatum, has been purified to homogeneity. The nucleotide sequence of this tRNA was determined to be: (see tests) Comparisons of the sequence and the modified nucleosides of this tRNA with those of other tRNAPhes thus far sequenced, indicate that this blue green algal tRNAPhe is typically prokaryotic and closely resembles the chloroplast tRNAPhes of higher plants and Euglena. The significance of this observation to the evolutionary origin of chloroplasts is discussed.

Treatment of the RNA of satellite tobacco necrosis virus (STNV) with phosphomonoesterase followed by heat denaturation and treatment with polynucleotide kinase in the presence of [gamma-32P]ATP yields a STNV [5'-32P]RNA containing a homogeneous 5' terminus. Analyses of this STNV [5'-32P]RNA yield the sequence of the first 42 nucleotides from the 5'terminus of STNV RNA. This nucleotide sequence contains the translation initiation AUG codon starting at position 30 from the 5' terminus as indicated by match of subsequent nucleotides with the genetic code assignments for the N-terminal amino acids of STNV coat protein in the 5'-terminal sequence ppAGUAAAGACAGGAAACUU-UACUGACUAACAUGGCAAAACAAC. An interesting feature of this sequence is its potential to form a hairpin loop structure involving perfect Watson-Crick base pairing between the first seven nucleotides and nucleotides at positions 16--22.

Over a 51/2-year period 30 patients were found with Eikenella corrodens infections of the hand following closed fist injury. Twenty-four had mixed infections; six grew pure cultures of Eikenella. Twenty-one of the 30 patients had positive cultures from an injured metacarpophalangeal joint. A delay in presentation or an inaccurate initial diagnosis appeared to be the most significant factors leading to the complications of osteomyelitis (in five patients) and significant loss of joint function (in eight other patients). Clinicians must have a high index of suspicion when evaluating any hand injury and clenched fist injuries of the hand should be treated by early adequate surgical debridement followed by IV penicillin given until operative cultures confirm or deny contamination with Eikenella corrodens.

In sequencing a 2200 bp region of the Neurospora crassa mitochondrial DNA encoding the 3' end of the large rRNA gene and a cluster of six tRNA genes, we have found that the tRNA genes are flanked by highly conserved GC-rich palindromic DNA sequences. An 18 bp long core sequence, 5'-CC CTGCAG TA CTGCAG GG-3', containing two closely spaced Pst I sites, is common to all these palindromic sequences. Each of the eight Pst I sites mapped in the 2200 bp region consists of two closely spaced Pst I sites; thus this 2200 bp long segment actually contains 16 Pst I sites. Between 5-10% of the N. crassa DNA may consist of these GC-rich palindromic sequences that include the 18 base long core sequence. The same core sequence is present within both the 5' and 3' side of the intervening sequence of the large rRNA gene, close to, but not at, the intron-exon boundaries. We discuss probable roles for these sequences in N. crassa mitochondrial function, including their role as signals either in the synthesis or processing (or both) of RNA in the mitochondria.

Static line injury to the military paratrooper's arm occasionally produces an unusual muscle injury: closed transection of the belly of the biceps brachii. A review of twenty-eight untreated paratroopers so injured demonstrated significant residual weakness and deformity. Attempts at late repair resulted in only minimum improvement. The results of twenty fresh injuries treated by either surgical repair or aspiration followed by closed reduction and splinting are presented.

A variety of names has been given to disorders of the inferior pole of the patella occurring in young athletic individuals and several different causes have been proposed for these disorders. Occasionally a direct blow will cause fracture of the inferior pole of the patella, but the only other mechanism which seems to be responsible is subluxation or dislocation. Ten cases of distal patellar pole fracture secondary to dislocation or subluxation of the patella are reported. From these cases and an extensive review of the literature it is concluded that patellar subluxation or dislocation is the usual common mechanism of distal patellar pole fractures in young, active individuals and that adequate treatment of this problem must address the patellar instability as well as the fracture.

The lysine isoacceptor tRNAs differ in two aspects from the majority of the other mammalian tRNA species: they do not contain ribosylthymine (T) in loop IV, and a 'new' lysine tRNA, which is practically absent in non-dividing tissue, appears at elevated levels in proliferating cells. We have therefore purified the three major isoaccepting lysine tRNAs from rabbit liver and the 'new' lysine tRNA isolated from SV40-transformed mouse fibroblasts, and determined their nucleotide sequences. Our basic findings are as follows. a) The three major lysine tRNAs (species 1, 2 and 3) from rabbit liver contain 2'-O-methylribosylthymine (Tm) in place of T. tRNA1Lys and tRNA2Lys differ only by a single base pair in the middle of the anticodon stem; the anticodon sequence C-U-U is followed by N-threonyl-adenosine (t6A). TRNA3Lys has the anticodon S-U-U and contains two highly modified thionucleosides, S (shown to be 2-thio-5-carboxymethyl-uridine methyl ester) and a further modified derivative of t6 A (2-methyl-thio-N6-threonyl-adenosine) on the 3' side of the anticodon. tRNA3Lys differs in 14 and 16 positions, respectively, from the other two isoacceptors. b) Protein synthesis in vitro, using synthetic polynucleotides of defined sequence, showed that tRNA2Lys with anticodon C-U-U recognized A-A-G only, whereas tRNA3Lys, which contains thio-nucleotides in and next to the anticodon, decodes both lysine codons A-A-G and A-A-A, but with a preference for A-A-A. In a globin-mRNA-translating cell-free system from ascites cells, both lysine tRNAs donated lysine into globin. The rate and extent of lysine incorporation, however, was higher with tRNA2Lys than with tRNA3Lys, in agreement with the fact that alpha-globin and beta-globin mRNAs contain more A-A-G than A-A-A- codons for lysine. c) A comparison of the nucleotide sequences of lysine tRNA species 1, 2 and 3 from rabbit liver, with that of the 'new' tRNA4Lys from transformed and rapidly dividing cells showed that this tRNA is not the product of a new gene or group of genes, but is an undermodified tRNA derived exclusively from tRNA2Lys. Of the two dihydrouridines present in tRNA2Lys, one is found as U in tRNA4Lys; the purine next to the anticodon is as yet unidentified but is known not be t6 A. In addition we have found U, T and psi besides Tm as the first nucleoside in loop IV.

A reproducible method of culturing leukocytes from rainbow trout (Salmo gairdneri) has been found. Using an atmosphere of 100 percent oxygen, we stimulated peripheral blood leukocytes to divide at 19 degrees C. Cultured cells were used for a karyological study; they had a modal chromosome number of 60 and a constant arm number of 104, a value previously reported for other tissues in these fish.

The nucleotide sequence G-T-Psi-C-G(A)- has previously been found in every tRNA of known sequence that is active in protein biosynthesis. An exception to this generalization is the recently sequenced initiator tRNA from yeast cytoplasm. It is now reported that cytoplasmic initiator tRNAs from wheat germ, rabbit liver, and sheep mammary gland also lack the G-T-Psi-C-G(A)- sequence. Thus: (i) nucleoside composition analyses show the absence of T in all these tRNAs; (ii) analyses of oligonucleotide fragments produced by T1 ribonuclease show the absence not only of the T-Psi-C-G(A)- sequence, but also of U-Psi-C-G(A)- or U-U-C-G(A)- sequences in such digests. The absence of G-T-Psi-C-G(A)- in the eukaryotic cytoplasmic initator tRNAs is, therefore, not simply due to lack of enzymatic modification of U to T.