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D Q Pham

Publications and source records attributed to D Q Pham.

9 recordsLinked to original sources
PubMed2000

Predictive intervals for age-specific fertility.

A multivariate ARIMA model is combined with a Gamma curve to predict confidence intervals for age-specific birth rates by 1-year age groups. The method is applied to observed age-specific births in Norway between 1900 and 1995, and predictive intervals are computed for each year up to 2050. The predicted two-thirds confidence intervals for Total Fertility (TF) around 2010 agree well with TF errors in old population forecasts made by Statistics Norway. The method gives useful predictions for age-specific fertility up to the years 2020-30. For later years, the intervals become too wide. Methods that do not take into account estimation errors in the ARIMA model coefficients underestimate the uncertainty for future TF values. The findings suggest that the margin between high and low fertility variants in official population forecasts for many Western countries are too narrow.

Birth Rate↗
PubMed2000

Structure and location of a ferritin gene of the yellow fever mosquito Aedes aegypti.

We have isolated and sequenced a genomic clone encoding the 24- and 26-kDa ferritin subunits in the mosquito Aedes aegypti (Rockefeller strain). The A. aegypti gene differs from other known ferritin genes in that it possesses an additional intron and an unusually large second intron. The additional intron is located within the 5' untranslated region, between the CAP site and the start codon. The second intron contains numerous putative transposable elements. In addition, unlike the human and rat ferritin genes, the A. aegypti ferritin gene is a single copy gene, located at 88.3% FLpter on the q-arm of chromosome 1. Primer extension analysis indicates that the A. aegypti ferritin gene has multiple transcriptional start sites. A differential usage of these sites is observed with varied cellular iron concentrations.

5' Untranslated Regions↗
PubMed1999

Transcriptional control is relevant in the modulation of mosquito ferritin synthesis by iron.

In yellow fever mosquito cells (Aag2 clone), iron treatment induces a threefold increase in ferritin message (fer mRNA) and protein (ferritin) by 16 h. These data contrast with work in mammalian hepatocytes and fibroblasts in which fer mRNA levels do not change with iron stimulation, but ferritin levels increase 50-fold. Pretreatment of the Aag2 cells with actinomycin D blocks induction of fer mRNA and reduces the ferritin subunit synthesis, suggesting that iron induction of ferritin subunit synthesis is subjected to transcriptional control. A putative iron-regulatory protein has also been identified in cytoplasmic extracts from Aag2 cells.

Aedes↗
PubMed1996

Manduca sexta hemolymph ferritin: cDNA sequence and mRNA expression.

A cDNA clone encoding a subunit of the tobacco hornworm Manduca sexta (Ms) hemolymph (serum) ferritin (Fer) has been identified and sequenced. The deduced amino acid (aa) sequence shows approx. 50% similarity to vertebrate Fer subunit sequences, and the nucleotide sequence contains a stem-loop structure in the 5' untranslated region that could serve as an iron-responsive element (IRE). The stem-loop of this putative IRE exhibits high identity to vertebrate IRE that play an essential role in the control of Fer synthesis. The Ms Fer subunit lacks one of the three Tyr residues required for the rapid biomineralization of iron shown in vertebrate heavy-chain Fer. In addition, aa residues that comprise the putative ferroxidase centers generally are not conserved, suggesting that the Ms Fer subunit more closely resembles the vertebrate light-chain subunit. Northern blot analyses indicate that the fer mRNA is expressed in the midgut, fat body and hemocytes, with the greatest expression in the midgut.

Amino Acid Sequence↗
PubMed1996

Purification of recombinant insect transferrin from large volumes of cell culture medium using high capacity Ni(2+)-dipicolylamine gel.

We report the purification of secreted recombinant Manduca sexta transferrin from Spodoptera frugiperda (Sf9) cell culture medium in a single step using high capacity Ni(2+)-dipicolylamine (DPA)-Novarose gel. Although the original sample was highly diluted (approximately 10 micrograms transferrin/ml medium) and the cell culture medium contained 10% surfactant (Pluronic F68) and a lipid emulsion, we were able to recover the recombinant transferrin (1 mg protein/100 ml) under gentle elution conditions with 70% yield at > 90% homogeneity. This work demonstrates the versatility of immobilized metal ion affinity chromatography using a high metal ion capacity gel to purify a recombinant protein and illustrates the potential of this affinity technique for protein separations from large volumes of cell culture media that contain surfactants.

Animals↗
PubMed1993

The 1629-bp open reading frame of the Autographa californica multinucleocapsid nuclear polyhedrosis virus encodes a virion structural protein.

A 1629-bp open reading frame (ORF) of Autographa californica multinucleocapsid nuclear polyhedrosis virus (AcMNPV) is shown to encode a 78-kDa virion structural protein. To determine this, polyclonal antibody was made to a fusion protein synthesized in Escherichia coli from a chimeric gene that contained 1415 bp of the 1629-bp gene. In Western blot analyses, this antibody cross-reacted with a protein of about 78 kDa in both extracellular virions (ECV) and virions isolated from polyhedra (PDV), and with a 78-kDa protein in PDV envelope preparations, but not with PDV nucleocapsids. This suggests that the protein encoded by the 1629-bp ORF is a virion envelope protein or a protein that occurs in the virion intermediate layer between the envelope and nucleocapsid.

Antibodies, Viral↗
PubMed1992

Sequence and in vitro translational analysis of a 1629-nucleotide ORF in Autographa californica nuclear polyhedrosis virus strain E2.

The complete nucleotide (nt) sequence of an open reading frame (ORF) (map unit 5.1 to 3.8) from Autographa californica nuclear polyhedrosis virus strain E2 (AcMNPV-E2) has been determined. This 1629-nt ORF has a coding potential for a 61-kDa Pro-rich protein. However, in vitro translation of the 1629-nt ORF and sodium dodecyl sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) revealed a 78-kDa protein product. The discrepancy between the M(r) predicted by the nt sequence and that obtained from the in vitro translational analysis is due to the high Pro content of this protein. The high Pro content causes anomalous migration of this protein during SDS-PAGE.

Amino Acid Sequence↗
PubMed1992

In vivo transcriptional analysis of three baculovirus genes: evidence of homology between viral and host transcripts.

Transcripts for the gp64 and polyhedrin genes as well as a 1629 open reading frame (1629 ORF) of the Autographa californica nuclear polyhedrosis virus were examined in the midgut tissues and hemocytes of uninfected and infected host Trichoplusia ni larvae and Sf21 cells. Polyhedrin-specific transcripts of 1.2, 3.4, and 4.9 kb were expressed in both infected larval tissues and infected Sf21 cells. The highest level of expression for polyhedrin-specific transcripts was observed in hemocytes, whereas the lowest level occurred in midgut. The expression of the 2.0-kb transcript for the gp64 gene increased continuously through 72 hr postinfection in the infected midgut tissues. This transcript was also observed in infected hemocytes, though its expression declined at 72 hr postinfection, as the expression for polyhedrin-specific transcripts peaked. The 1629 ORF transcripts of 2.0 and 3.2 kb were expressed in both types of infected tissues. More significantly, a 1629-ORF-specific probe detected host transcripts of 0.7 and 2.5 kb in uninfected midgut tissues as well as transcripts of 2.5, 8.8, and 11.0 kb in uninfected hemocytes under high stringency conditions. The latter results indicate that these host transcripts share homology with the 1629 ORF gene.

Animals↗