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We have used combinatorial chemistry with amino acid mixtures (X) at positions 6 to 23 in vasoactive intestinal peptide (VIP) to optimize binding affinity and selectivity to the rat VPAC(1) receptor. The most efficient amino acid replacement was a substitution of alanine at position 18 to diphenylalanine (Dip), increasing the displacement efficiency of (125)I-VIP by 370-fold. The [Dip(18)]VIP(6-23) was subsequently used to find a second replacement, employing the same approach. Tyrosine at position 9 was selected and the resulting [Tyr(9),Dip(18)]VIP(6-23) analog has a K(i) value of 90 nM. This analog was unable to stimulate cAMP production at 10(-6) M but was able to inhibit VIP-induced cAMP stimulation (K(b) = 79 nM). The K(i) values of [Tyr(9),Dip(18)]VIP(6-23) using the rat VPAC(2) and PAC(1) receptors were 3,000 nM and >10,000 nM, respectively. Thus, [Tyr(9),Dip(18)]VIP(6-23) is a selective VPAC(1) receptor antagonist. The C-terminally extended form, [Tyr(9),Dip(18)]VIP(6-28), displays improved antagonistic properties having a K(i) and K(b) values of 18 nM and 16 nM, respectively. On the contrary, the fully extended form, [Tyr(9),Dip(18)]VIP(1-28), was a potent agonist with improved binding affinity (K(i) = 0.11 nM) and ability to stimulate cAMP (EC(50) = 0.23 nM) compared with VIP (K(i) = 1.7 nM, EC(50) = 1.12 nM). Furthermore, the specificity of this agonist to the VPAC(1) receptor was high, the K(i) values for the VPAC(2) and PAC(1) receptors were 53 nM and 3,100 nM, respectively. Seven other analogs with the [Tyr(9),Dip(18)] replacement combined with previously published VIP modifications have been synthesized and described in this work.

A full-length cDNA clone encoding the human mitochondrial tryptophanyl-tRNA synthetase (h(mt)TrpRS) has been identified. The deduced amino acid sequence shows high homology to both the mitochondrial tryptophanyl-tRNA synthetase ((mt)TrpRS) from Saccharomyces cerevisiae and to different eubacterial forms of tryptophanyl-tRNA synthetase (TrpRS). Using the baculovirus expression system, we have expressed and purified the protein with a carboxyl-terminal histidine tag. The purified His-tagged h(mt)TrpRS catalyzes Trp-dependent exchange of PP(i) in the PP(i)-ATP exchange assay. Expression of h(mt)TrpRS in both human and insect cells leads to high levels of h(mt)TrpRS localizing to the mitochondria, and in insect cells the first 18 amino acids constitute the mitochondrial localization signal sequence. Until now the human cytoplasmic tryptophanyl-tRNA synthetase (hTrpRS) was thought to function as the h(mt)TrpRS, possibly in the form of a splice variant. However, no mitochondrial localization signal sequence was ever detected and the present identification of a different (mt)TrpRS almost certainly rules out that possibility. The h(mt)TrpRS shows kinetic properties similar to human mitochondrial phenylalanyl-tRNA synthetase (h(mt)PheRS), and h(mt)TrpRS is not induced by interferon-gamma as is hTrpRS.

A complete ribosomal DNA (rDNA) repeat unit has been cloned from the genome of Pisum sativum (garden pea) and used to construct a map containing a total of 58 cleavage sites for 23 different restriction enzymes. Regions encoding 18s and 25s ribosomal RNA (rRNA) were identified by R-loop analysis. A 180 bp sequence element is repeated eight times in the intergenic ‘nontranscribed spacer’ (NTS) region, as defined by eight evenly spaced RsaI cleavage sites. Sequence heterogeneity among these elements (subrepeats) is indicated by the presence of an NcoI site within the five RsaI subrepeats distal to the 25s rRNA gene but not in the three subrepeats proximal to this gene, and also by the presence of an additional RsaI cleavage site in one subrepeat.

A cleavage map of a recombinant plasmid carrying Tn10 was constructed for 13 different restriction enzymes. The Tn10 region of this plasmid contains cleavage sites for BamHI, AvaI, BglI, BglII, EcoRI, XbaI, HincII, HindIII, and HpaI. Restriction enzymes PstI, SmaI, KpnI, XhoI, SalI, and PvuI do not cleave within the Tn10 element. This map confirms the previously reported structure of this transposon; it is composed of a unique sequence (approximately6,400 base pairs long), which in part codes for the tetracycline resistance functions and is bounded by inverted repeats (approximately 1,450 base pairs long).

Prostaglandin dehydrogenase (PGDH), Δ13-reductase, and total PGDH activities (the sum of the first two activities) were measured in rat testicular parenchymal and capsular preparations from 11 through 81 days of age. Δ13-Reductase activity closely paralleled PGDH activity and was substrate dependent except for the parenchymal activity at 61 and 81 days of age when something appeared to enhance its activity. All three activities, when expressed on a per milligram of tissue basis, were elevated at 11 days postpartum and then decreased to a low value at 21 days of age for the parenchyma and 21-32 days of age for the capsule. The elevated activity at 11 days of age suggested a possible elevation of enzyme activity by placental gonadotropins or possibly progesterone. Maximal activity was observed at 51 days of age for the parenchyma and 61 days for the capsules with diminished activities observed with advancing age except for the parenchymal Δ13-reductase activity. On a per milligram of tissue basis, the capsule demonstrated more enzyme activity than did the parenchyma with maximal activities being observed at 51 days of age. Possible control mechanisms were the following: substrate induction, gonadotropins, testosterone, or those factors regulating testosterone secretion.

The location of Tn10 genes encoding tetracycline resistance and its regulation was determined by analyzing the properties of recombinant plasmids carrying partial HpaI digestion products of lambda::Tn10 transducing phage deoxyribonucleic acid. Within a 2,700-base pair region are encoded tetracycline resistance, the structural gene (tet) for a tetracycline-inducible polypeptide, and the regulatory elements for the induction of both the resistance phenotype and the polypeptide. Fusion of different sequences to an HpaI site in the tet gene alters the molecular weight and stability of the polypeptide as well as the tetracycline resistance phenotype of strains producing fusion polypeptides. These results indicate the orientation of the tet gene and support the conclusion that the tet polypeptie is required for tetracycline resistance. A HincII cleavage site immediately upstream from the tet gene is protected by ribonucleic acid polymerase, but only the absence of ribonucleotide triphosphates. The possibility that tet transcription is initiated at this site is discussed.

The 2'-5' oligoadenylate synthetases form a well conserved family of interferon induced proteins, presumably present throughout the mammalian class. Using the Expressed Sequence Tag databases, we have identified a novel member of this family. This protein, which we named p59 2'-5' oligoadenylate synthetase-like protein (p59OASL), shares a highly conserved N-terminal domain with the known forms of 2'-5' oligoadenylate synthetases, but differs completely in its C-terminal part. The C-terminus of p59OASL is formed of two domains of ubiquitin-like sequences. Here we present the characterisation of a full-length cDNA clone, the genomic sequence and the expression pattern of this gene. We have addressed the evolution of the 2'-5' oligoadenylate synthetase gene family, in the light of both this new member and new 2'-5' oligoadenylate synthetase sequence data from other species, which have recently appeared in the databases.

PTC 11 Committee, the ASME Performance Test Code Committee charged with producing a new test code for large industrial fans, has decided to present code users with two options for expressing fan performance. While one of these options is representative of current U.S. practice, the other option appears to be quite different. The differences center around the definitions of fan flow rate and fan output. Historically, fan flow rate has been defined as the volume flow rate at the fan inlet, and fan output has been defined as either the rise in total pressure across the fan or as the rise from the total pressure at the inlet to the static pressure at the outlet. The alternative method uses the mass flow rate and the “fan specific energy” as the performance variables. If the fan process is incompressible, the two sets of variables produce easily reconciled values; however, if compressibility must be accounted for, subtle differences may arise. This paper examines the assumptions and developments of the two alternative methods of expressing fan performance.

In the course of a heterologous transposon tagging experiment in Petunia hybrida (n=7), 135 independent T-DNA loci were tested for linkage to the target genes Hf1 and Fl, which are located on the two largest chromosomes. Approximately one-third (47) of these T-DNA loci were linked to one of these two markers. Of these 47 linkedloci, 19 mapped within 1 cM of its marker, indicating a highly non-random genetic distribution of introduced loci. However, rather than non-random integration within both of the marked chromosomes, this probably reflects a suppression of recombination around these marker loci in the particular wide hybrids used for mapping. This hypothesis was tested by measuring recombination between linked T-DNAs in an inbred background. Inbred recombination levels were found to be at least 3-fold higher around the Hf1 locus and 12-fold higher around Fl compared to the wide hybrids. These findings may reflect the origin of P. hybrida by hybridization of wild species, and while relevant to genetic mapping in petunia in particular they may also have more general significance for any mapping strategies involving the use of wide hybrids in other species.

Milk proteins were subjected to treatment with various levels of benzoyl peroxide, with and without heating at 60 C for 2 h. Heating had a pronounced effect on whey proteins, but polyacrylamide gel electrophoresis revealed changes in proteins not attributable to heat alone. The effect on proteins was reflected in an increased tendency for the benzoyl peroxide-heat treated cheeses to expel moisture during leakage tests. Use of 17.8 ppm benzoyl peroxide resulted in a markedly whiter cheese than that made using 5.9 ppm and reflectance studies indicated this to be true even when no heat treatment accompanied the benzoyl peroxide. Use of benzoyl peroxide in the bleaching process did not decrease mold development in ripening loaves nor was acid production by lactic cultures diminished. In addition, proteolysis of milk proteins by rennet was not reduced by the presence of benzoyl peroxide.

Spacer-length (sl) variation in ribosomal RNA gene clusters (rDNA) was surveyed in 502 individual barley plants, including samples from 50 accessions of cultivated barley, 25 accessions of its wild ancestor, and five generations of composite cross II (CCII), an experimental population of barley. In total, 17 rDNA sl phenotypes, made up of 15 different rDNA sl variants, were observed. The 15 rDNA sl variants comprise a complete ladder in which each variant differs in length from adjacent variants by approximately equal to 115 nucleotide pairs. Studies of four rDNA sl variants in an F2 population showed that these variants are located at two unlinked loci, Rrn1 and Rrn2, each with two codominant alleles. Using wheat-barley addition lines, we determined that Rrn1 and Rrn2 are located on chromosomes 6 and 7, respectively. The nonrandom distribution of sl variants between loci suggests that genetic exchange occurs much less frequently between than within the two loci, which demonstrates that Rrn1 and Rrn2 are useful as new genetic markers. Frequencies of rDNA sl phenotypes and variants were monitored over 54 generations in CCII. A phenotype that was originally infrequent in CCII ultimately became predominant, whereas the originally most frequent phenotype decreased drastically in frequency, and all other phenotypes originally present disappeared from the population. We conclude that the sl variants and/or associated loci are under selection in CCII.

The structural and regulatory functions encoding tetracycline resistance in transposon Tn10 lie within a 2,700-base pair region. Using recombinant plasmids with different deoxyribonucleic acid sequences adjacent to a HincII site in this region, we located the promoter controlling the expression of tetracycline resistance. These various sequences conferred altered levels of tetracycline resistance. Plasmids containing deletions of a 695-base pair HincII fragment were constitutive and showed the loss of a 23,000-dalton tetracycline-inducible polypeptide, thus identifying the repressor and the location of its gene.

Eighty-four first-year grazing Holstein-Friesian steers were observed through 2 years on 40 ha of reclaimed unfertilized grassland with the objective of investigating the influence of stocking rate (SR) on internal parasitism under extensive grazing conditions. Three groups of steers were grazed each year at low, medium and high SR in separate paddocks (0.53, 1.05 and 1.55 steers/ha). The faecal egg counts of predominantly Cooperiaand Ostertagiaspp. were influenced by SR in the first year (p<0.05) with maximum geomet-ric means of 135,182 and 217 epg in the low, medium and high SR groups, respectively, and part of the second year (p=0.08) with maximum geometric means of 88, 134 and 195 epg. In the second year, all steers were treated with levamisole by 26 July due to di-arrhoea, being particularly severe at high SR and 7 steers were withdrawn from this group at the same time. Serum pepsinogen levels indicated a higher rate of uptake of Os-tertagialarvae in higher SR groups in the second season before treatment (p<0.01).The mean weight gains (± s.d.) for the first year were 630±58, 341 ±97 and 300±151 g/day in the low, medium and high SR groups, respectively, and in the second year the corre-sponding figures were 565±109, 357±135 and 247±129 g/day. Although the SRs were much lower than commonly found on improved pastures, we conclude that feed on of-fer was a limiting factor in late season and secondly, that the levels of exposure and up-take of nematodes in steers were affected by SR. The levels of parasitism at the medium and high SR were high enough to have affected production.

Rumen motility was recorded on an experimental cow by means of telemetrie signal transfer from strain gauge force transducers fixed surgically on the peritoneal surface of the rumen wall in the left flank. The normocalcaemic cow was given a standard milk fever treatment with calcium borogluconate (400 ml with 14 mg Ca/ml) intravenously. Transient clinical signs were: decreased rumination, muscle ticks, salivation and a heart rate reduction of 20%. Rectal temperature remained unaltered. Frequency of rumen con-tractions was reduced up to 40% whereas amplitude of contractions did not deviate from baseline values. Hypocalcaemia was induced in a second experiment by iv infusion of Na2EDTA. At 0.60 mmol/1 ionized blood calcium periods of no motility were recorded whereas inactivity of rumen activity was persistent at 0.55 mmol/1 ionized blood cal-cium. The cow went down at 0.45-0.48 mmol/1 ionized blood calcium at which point the heart rate was increased by 40%. The high sensitivity of the method employed allowed the conclusion that already at a concentration of ionized blood calcium at 1.0 mmol/1 both frequency and amplitude of rumen contractions decreased rapidly although eating behaviour and rumination appeared unaffected during the short term observation peri-ods. Implications of this finding towards health and production in transition cows are discussed.

264 larvae and two eggs of the goat warble fly were collected in 1970, 1971 and 1972.Culture of larvae on various media in the laboratory was unsuccessful. Some mature third instar larvae pupated naturally and 13 flies eventually emerged.A description is given of the eggs, which are unlike any others so far described, and a description of a pupa that developed from a larva identified as P. aegagri is also given.Warbles were seen in goats from early October to early March. Pupation lasted between 45 and 76 days, but nearly all flies emerged in mid-April during a period of warm weather. The two eggs were collected from goats in the field towards the end of April.Larvae and flies were identified as P. aegagri, P. silenus and P. crossii according to descriptions given in the literature, but larvae that were identified as one species gave rise to flies that were identified as another species. Larvae with different characteristics were collected on occasions from the same flock at the same time.It is concluded that the criteria given in the literature for separating the species are inadequate. Provided the description of the eggs of P. crossii is correct, then Grunin's decision to synonymise the three species must be wrong, because the eggs found on goats in Cyprus were distinctly different from the eggs of P. crossii. If synonymy is accepted, then there must be yet another species present in Cyprus.

Transgenic petunia plants with suppressed chalcone synthase gene expression produce abnormal anthers devoid of flavonoid pigments. Although viable pollen is produced, pollen germination and tube growth are severely reduced both in vivo and in vitro. This results in plants that are self-sterile. Pollen from the transgenic plants is partially rescued by inbred V26 stigmas, resulting in seed set that is approximately 30% of normal. Female fertility in the transgenic petunia is unaffected by the lack of flavonoids. We propose the term conditional male fertility (CMF) to describe the state in which viable but flavonoid-deficient pollen does not function in self-crosses and is partially functional on wild-type stigmas. Although this condition has attributes of both male sterility and self-incompatibility, it is clearly different. This observation in petunia has similarities to the earlier report of Coe et al. (1981) that most pollinations made with chalcone synthase (CHS)-deficient maize pollen were unsuccessful. The possibility that normal development of the male gametophyte requires flavonoid synthesis in many or all higher plants is discussed. The dominant CHS deficiency and male sterility in petunia, taken together with the recessive CHS deficiency and male sterility in maize, suggest that flavonoid synthesis in the sporophyte rather than the gametophyte is required for fertility.

Highlights changes stemming from the 1990 Clean Air Act Amendments. Requirement of reducing emissions of hazardous air pollutants; Necessity for managers to invest time in selecting the compliance alternative most suited to their business goals.

Focuses on the leadership of the state of Arkansas in terms of ambient air quality. Effect of low population; Determination of compliance to air quality standards; Advantages of the state's air quality status to industrial facilities; Attractions of the state to relocating industries.