Germ-line transformation of the Australian sheep blowfly Lucilia cuprina.

The Australian sheep blowfly, Lucilia cuprina, is the most important economic insect pest for the sheep industries in Australia and New Zealand. piggyBac-mediated germ-line transformation of L. cuprina was achieved with a helper plasmid that had the Drosophila melanogaster hsp70 promoter controlling expression of the transposase and a piggyBac vector with an EGFP marker gene. Two transformant lines were obtained, at a frequency of approximately 1-2% per fertile G0. One of these lines has a single copy of the transgene, the other most likely has four copies. This is the first report of germ-line transformation of L. cuprina and is an important step towards the generation of engineered strains that would be suitable for male-only release eradication/suppression programmes.

Relative efficacy of organophosphorus insecticides against susceptible and resistant strains of the strike blowfly Lucilia cuprina (Calliphoridae) in New Zealand sheep.

Four groups of five Romney lambs were treated by plunge dipping with one of four registered organophosphorus flystrike preventatives. Untreated lambs acted as controls. The sheep were challenged at weekly intervals with larval implants of organophosphate-susceptible and -resistant strains of Lucilia cuprina. All four treatments provided 19-21 weeks protection against susceptible larvae but chlorfenvinphos provided the longest protection (16-17 weeks), followed by propetamphos (15-16 weeks), dichlofenthion (10-13 weeks) and diazinon (9-13 weeks), against the resistant strain.

A domain that assumes a Z-conformation includes a specific deletion in some cloned variants of a complex satellite.

Sequence analyses show that deletions of 10 and 12 bp occur at homologous sites in a domain that is rich in alternating purines and pyrimidines (Pu/Py) in B42 and EXT, two cloned variants of a complex satellite DNA. A 3-bp deletion occurs 27 bp upstream from the site of the specific deletions in B42 and RU, a third cloned satellite variant that has not suffered the 10-bp deletion. Under torsional stress, the Pu/Py-rich domain adopts a Z-conformation as shown by (i) inhibition of cutting at a BssHII site that accounts for 2/5 of a 15-bp tract of pure Pu/Py in the domain; (ii) binding of polyclonal and monoclonal anti-Z-DNA antibodies to the domain; and (iii) antibody stabilization and subsequent relaxation of the Z-region.

Molecular cloning of cDNAs cognate to genes sensitive to hormonal control in rat liver.

Poly(A)-RNAs were prepared from livers of rats treated with hydrocortisone and cycloheximide, then enriched for large mRNAs by successive sucrose gradients and gel electrophoresis. The size-selected RNAs were used as templates for synthesis of double-stranded cDNAs that were cloned in Escherichia coli using the pBR322 plasmid vector. Recombinant plasmids characterized as carrying inserts of potential interest were further analyzed by differential hybridization to mRNAs from untreated and hydrocortisone-treated rats. Seven of the cloned cDNAs were identified as complementary to mRNAs whose content in liver is sensitive to modulation by the steroid. Further screening for hormonal responsiveness revealed that two of the cloned cDNAs hybridize to a 3.4-kilobase mRNA that is rapidly induced in liver by treatment with insulin or cAMP as well as by hydrocortisone; restriction enzyme analysis demonstrated that the cDNAs from these two clones are derived from the same mRNA. In isolated nuclei, the rate of transcription of this mRNA is increased by each of the inducing hormones. This unusually regulated mRNA codes for a protein of 53 kDa on denaturing gels, undergoes rapid intracellular degradation that is prevented by cycloheximide, and appears to be the product of a single copy gene.

Demonstration of remarkable sequence divergence in variants of a complex satellite DNA by molecular cloning.

Repeat units of a complex G + C-rich satellite of the Bermuda land crab have been cloned by insertion into either the PstI or EcoRI site of pBR322 or the EcoRI site of pUC9. While most of the recombinants contained inserts of approx. 2.1 kb, the average size of repeat units seen in cellular satellite digests, several inserts were markedly different in size. Two domains that account for major sequence differences among the satellite variants and that may be 'hotspots' for sequence modification have been subcloned to permit characterization of their secondary and tertiary structures independent of the influence of the other unusual sequences present. One of these domains is striking in its content of simple repeats; one strand is highly biased in pyrimidines which may permit the formation of unusual secondary and/or tertiary conformations. The other subcloned domain is rich in Pu/Py; preliminary data indicate a transition from B----Z DNA in this region.

Q beta replicase containing a Bacillus stearothermophilus elongation factor.

We purified Q beta replicase containing EF-Ts from Bacillus stearothermophilus in place of the homologous polypeptide from Escherichia coli. The hybrid enzyme was fully active in the transcription of a variety of templates. It was found to be qualitatively similar to native Q beta replicase with respect to a variety of parameters which measure the efficiency of initiation of RNA synthesis. The results demonstrated that Q beta replicase can tolerate substantial alterations in the EF-Tu X Ts component of the enzyme. These alterations resulted in only minor perturbations of catalytic properties.

Protein synthesis elongation factors Tu and Tu.Ts from Caulobacter crescentus: sensitivity to kirromycin and activity in Q beta replicase.

The protein synthesis elongation factors Tu and Ts are responsible for binding aminoacyl-transfer ribonucleic acid (RNA) to the ribosome. In addition, they perform an undefined function, as the EF-Tu.Ts complex, in the RNA phage RNA replicases. In an effort to obtain insight into these two apparently unrelated roles, we purified the elongation factors from Caulobacter crescentus and compared them to the analogous Escherichia coli polypeptides. Although most physical and functional characteristics were found to be similar, significant differences were found in the molecular weight of EF-Ts and relative affinities of guanine nucleotides, sensitivity to trypsin cleavage, and rate of heat denaturation of EF-Tu. The antibiotic kirromycin was active with EF-Tu from both bacterial species. When C. crescentus EF-Tu.Ts was substituted for the E. coli elongation factors in Q beta phage RNA replicase, an enzyme capable of apparently normal RNA synthetic activity was formed.

Adolescent fertility in Hawaii: implications for planning.

PIP: Computer printouts of cross tabulations of selected data from the vital records for live births, infant and fetal deaths, marriages, and divorces which took place in Hawaii during 1968, 1969, 1970, 1971 and 1972 were studied in order to describe the characteristics of young parenthood in Hawaii from 1968-1972; identify special at-risk populations during preconception, interconception, pregnancy and parenting; identify children of at-risk mothers; identify trends which may affect the planning, delivery, and evaluation of needed programs and services; and determine the need for and nature of specific, modified, and innovative services to teens and preteens. Findings reported by school districts showed marked differences in pregnancy rates, premature births, and infant deaths. The 3 schools with the highest fetal death and induced abortion ratios had the lowest live birth and pregnancy rates. The 6 with lowest fetal death ratios had the highest live birth and pregnancy rates. The findings enable planning of specific health care delivery and school health programs for school districts with the highest pregnancy, premature birth, and infant death rates. Included among the recommendations are the following: 1) the data presented should be used as a bseline for program and service evaluation; 2) family life education efforts in those schools showing the greatest need should be increased; 3) prenatal care should be made more readily available and acceptable to young mothers in the high priority school district; and 4) support services for single-parent families should be planned to meet the increasing need for such services.^ieng