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B Buckley

Publications and source records attributed to B Buckley.

32 records · Page 2Linked to original sources
PubMed1992

Cap structure of U3 small nucleolar RNA in animal and plant cells is different. gamma-Monomethyl phosphate cap structure in plant RNA.

U3 small nucleolar RNA (snoRNA) is an abundant small RNA involved in the processing of pre-ribosomal RNA of eukaryotic cells. U3 snoRNA has been previously characterized from several sources, including human, rat, mouse, frog, fruit fly, dinoflagellates, slime mold, and yeast; in all these organisms, U3 snoRNA contains trimethylguanosine cap structure. In all instances where investigated, the trimethylguanosine-capped snRNAs including U3 snoRNA, are synthesized by RNA polymerase II. However, in higher plants, the U3 snoRNA is synthesized by RNA polymerase III and contains a cap structure different from trimethylguanosine (Kiss, T., and Solymosy, F. (1990) Nucleic Acids Res. 18, 1941-1949; Marshallsay, C., Kiss, T., and Filipowicz, W. (1990) Nucleic Acids Res. 18, 3451-3458; Kiss, T., Marshallsay, C., and Filipowicz, W. (1991) Cell 65, 517-526). In this study, we present evidence that cowpea and, most likely, tomato plant U3 snoRNA contains a methyl-pppA cap structure. These data show that the same U3 snoRNA contains different cap structures in different species and suggest that the kind of cap structure that an uridylic acid-rich small nuclear RNA contains is dependent on the RNA polymerase responsible for its synthesis. In vitro synthesized plant U3 snoRNA, with pppA or pppG as its 5' end, was converted to methyl-pppA/G cap structure in vitro when incubated with extracts prepared from wheat germ or HeLa cells. These data show that the capping machinery is conserved in organisms as evolutionarily distant as plants and mammals. Nucleotides 1-45 of tomato U3 snoRNA, which are capable of forming a stem-loop structure, are sufficient to direct the methyl cap formation in vitro.

Animals↗
PubMed1991

Photic sneezing.

Explore the source record for details and available documents.

Humans↗
PubMed1991

Effect of mean airway pressure on gas exchange during high-frequency oscillatory ventilation.

We studied the effect of mean airway pressure (Paw) on gas exchange during high-frequency oscillatory ventilation in 14 adult rabbits before and after pulmonary saline lavage. Sinusoidal volume changes were delivered through a tracheostomy at 16 Hz, a tidal volume of 1 or 2 ml/kg, and inspired O2 fraction of 0.5. Arterial PO2 and PCO2 (PaO2, PaCO2), lung volume change, and venous admixture were measured at Paw from 5 to 25 cmH2O after either deflation from total lung capacity or inflation from relaxation volume (Vr). The rabbits were lavaged with saline until PaO2 was less than 70 Torr, and all measurements were repeated. Lung volume change was measured in a pressure plethysmograph. Raising Paw from 5 to 25 cmH2O increased lung volume by 48-50 ml above Vr in both healthy and lavaged rabbits. Before lavage, PaO2 was relatively insensitive to changes in Paw, but after lavage PaO2 increased with Paw from 42.8 +/- 7.8 to 137.3 +/- 18.3 (SE) Torr (P less than 0.001). PaCO2 was insensitive to Paw change before and after lavage. At each Paw after lavage, lung volume was larger, venous admixture smaller, and PaO2 higher after deflation from total lung capacity than after inflation from Vr. This study shows that the effect of increased Paw on PaO2 is mediated through an increase in lung volume. In saline-lavaged lungs, equal distending pressures do not necessarily imply equal lung volumes and thus do not imply equal PaO2.

Animals↗
PubMed1990

Effect of actinomycin D on replication of satellite tobacco ringspot virus RNA in plant protoplasts.

We have developed a three-component system of host, tobacco ringspot virus (TobRV), and satellite tobacco ringspot virus RNA (sTobRV RNA) for investigating the specific contributions of host components or TobRV gene products to the propagative cycle of satellite RNA. Cowpea (Vigna unguiculata) protoplasts were inoculated with sTobRV and TobRV genomic RNAs by electroporation. An increase in sTobRV RNA was detected both by blot hybridization and by incorporation of [14C]uridine into material with the electrophoretic mobility of sTobRV RNA. DNA-dependent RNA synthesis in uninoculated protoplasts was effectively inhibited by 50 micrograms/ml actinomycin D (Act D) in the medium. Addition of Act D to protoplasts 24 or 48 hr after coinoculation with sTobRV RNA and TobRV genomic RNAs had little effect on accumulation of sTobRV RNA, whereas addition at 24 hr prior to coinoculation prevented any detected accumulation of sTobRV RNA of either polarity. Our results and previous findings of RNA complementary to encapsidated satellite RNA in extracts of infected tissue suggest that an RNA-dependent RNA polymerase is responsible for the synthesis of sTobRV RNA. The strongly inhibitory effect of Act D when added early implies a role for a host factor in the early phase of sTobRV RNA replication.

Dactinomycin↗
PubMed1987

The cap-binding protein complex in uninfected and poliovirus-infected HeLa cells.

In poliovirus-infected HeLa cells, the mechanism of protein synthesis initiation factor recognition of m7G cap groups on mRNA is impaired. Translation of capped host cell mRNAs is inhibited, whereas translation of uncapped poliovirus mRNA proceeds exclusively. The site of this defect has been localized to the cap-binding protein complex (CBPC). To elucidate the specific structural and functional defects of the CBPC following poliovirus infection, the CBPC and/or its polypeptide components were purified from uninfected and poliovirus-infected HeLa cells. The CBPC from uninfected cells consisted of tightly associated 24- and 220-kDa polypeptides; minor amounts of polypeptides of 40, 44, and 80 kDa also consistently co-purified with the p24/p220 cores. No evidence of a 50-kDa, eIF-4A-related polypeptide subunit of the CBPC was obtained. The CBPC from poliovirus-infected cells had undergone major structural alterations. The 220-kDa component was absent; antigenically related (100-130 kDa) degradation products were present instead. The 24-kDa component co-purified with the p220 degradation products, but other components were missing. The association of the infected cell CBPC components was quite labile compared with that demonstrated by the components of CBPC from uninfected cells. Differential stimulation of capped, but not uncapped mRNAs in a cell-free translation assay was demonstrated by unmodified CBPC. Conversely, modified CBPC from poliovirus-infected cells differentially stimulated in vitro translation of uncapped poliovirus mRNA but not capped mRNAs. The implications of these results for the mechanism of cap-independent translation are briefly discussed.

Carrier Proteins↗
PubMed1986

Two-dimensional gel analyses of the 24-kDa cap binding protein from poliovirus-infected and uninfected HeLa cells.

The 24-kDa cap binding protein (CBP) from uninfected, mock-infected and poliovirus-infected HeLa cell extracts was isolated by m7GTP affinity chromatography and examined by isoelectric focusing followed by SDS-PAGE. Two major species (pI 6.7 and 7.1) and two minor species (pI 6.5 and 6.8) were found in all cases. Preparations from postribosomal supernate (S200) and the supernate from 0.5 M KCl washed ribosomes (RSW) also demonstrated these same four species. We conclude that there are no detectable differences between ribosome-associated and soluble 24-kDa CBP and that the 24-kDa CBP is not detectably altered by poliovirus infection. We also report the presence of a previously undescribed 16-kDa polypeptide(s) doublet that copurifies with the 24-kDa CBP from uninfected, mock-infected and poliovirus-infected HeLa cells.

Carrier Proteins↗
PubMed1984

Elimination of germ-line tandemly repeated sequences from the somatic genome of the ciliate Oxytricha fallax.

The ciliated protozoa exhibit nuclear dimorphism. The genome of the somatic macronucleus arises from the germ-line genome of the micronucleus following conjugation. We have studied the fates of highly repetitious sequences in this process. Two cloned, tandemly repeated sequences from the micronucleus of Oxytricha fallax were used as probes in hybridizations to micronuclear and macronuclear DNA. The results of these experiments show: (1) the cloned repeats are members of two apparently unrelated repetitious sequence families, which each appear to comprise a few percent of the micronuclear genome, and (2) the amount of either family in the macronuclei from which our DNA was prepared is about 1/15 that found in an equal number of diploid micronuclei. Most, if not all, of the apparent macronuclear copies of these repeats can be accounted for by micronuclear contamination, which strongly suggests that these sequences are eliminated from the macronuclei and have no vegetative function.

Cell Nucleus↗
PubMed1980

Q fever epidemic in Victorian general practice.

In 1979, 110 people associated with a local rural abattoir presented with an acute febrile illness thought to be Q fever. Of these, 70 were shown by serotesting to have had Q fever, and one was shown to have had leptospirosis alone. Four individuals had mixed infections of Q fever with another zoonotic infection, two with leptospirosis, and two with brucellosis. Only 44% of suspected cases of Q fever were shown to have complement-fixing antibodies to Q fever four weeks after the infection, but 74% had anti-bodies 12 weeks after infection. This epidemic of Q fever occurred soon after the abattoir began to slaughter feral goats for the first time; there is reason to believe that the epidemic may have been related to the introduction of this practice.

Abattoirs↗
PubMedDate not supplied

Using observational information in planning and implementation of field studies with children as subjects.

Children have been one of the least-studied populations for estimating environmental exposure, even though they are cited as a sensitive subgroup for diseases derived from environmental exposure. This trend appears to be changing as more studies are conducted with children as subjects. It consequently becomes increasingly important to gather and use observational data in all phases of the study. Observational data are the key for both defining the pathway of exposure and for assessing effectiveness of the data-collection protocols. Obtaining quality data from a study involving children requires: efficient use of observational data, collection of meaningful personal and microenvironmental samples, linkage of observational data to the collected samples, and personnel trained to work with children using pilot-tested protocols. Although all of these help to ensure the quality of the data, the utility of the data is often determined by observational feedback from those who collected it. Laboratory-derived protocols should be living documents and observations from the field should be used to modify the data-collection methods when practical.

Child↗