Amplification of alpha-fetoprotein complementary DNA by insertion into a bacterial plasmid.

A fragment of the α-fetoprotein (AFP) structural gene was purified and amplified by bacterial cloning techniques. Double-stranded DNA_AFP was constructed from a cDNA copy of greater than 95% pure mRNA_AFP and inserted into E. coli plasmid pBR322 by poly(dA-dT)-linkers. Chimeric plasmid DNA isolated from transformants of E. coli strain χ1776 have been shown to contain α-fetoprotein sequences by hybridization to labeled mRNA_AFP. One clone, designated pA5 (chimeric plasmid pBR322 containing a cDNA_AFP sequence isolated from clone 5), has been studied in more detail. The inserted sequence of approximately 950 nucleotide pairs was positively identified by a hybridization-translation procedure. Hybridization of [³H]uridine-labeled poly(A)-containing RNA from an AFP-secreting cell line to excess pA5 DNA immobilized on nitrocellulose filters was used to show the selectivity of this probe for detecting expression of the AFP gene.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Rat growth hormone gene: intervening sequences separate the mRNA regions.

Rat genomic DNA was digested with various restriction endonucleases, separated by gel electrophoresis and hybridized to 125 I-labeled mRNA for the precursor protein to growth hormone. Restriction sites were found within the genomic DNA that were not found in the previously reported DNA sequence corresponding to the mRNA (19). It appears that the gene for growth hormone contains intervening sequences separating the DNA regions that specify mRNA sequences.     

Extraordinary resistance to insecticides reveals exotic Q biotype of Bemisia tabaci in the New World

A strain of the whitefly Bemisia tabaci (Gennadius) possessing unusually high levels of resistance to a wide range of insecticides was discovered in 2004 in the course of routine resistance monitoring in Arizona. The multiply resistant insects, collected from poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) plants purchased at a retail store in Tucson, were subjected to biotype analysis in three laboratories. Polyacrylamide gel electrophoresis of naphthyl esterases and sequencing of the mitochondrial cytochrome oxidase I gene (780 bp) confirmed the first detection of the Q biotype of B. tabaci in the New World. This U.S. Q biotype strain, referred to as Poinsettia'04, was highly resistant to two selective insect growth regulators, pyriproxyfen and buprofezin, and to mixtures of fenpropathrin and acephate. It was also unusually low in susceptibility to the neonicotinoid insecticides imidacloprid, acetamiprid, and thiamethoxam, relative to B biotype whiteflies. In 100 collections of whiteflies made in Arizona cotton (Gossypium spp.), vegetable, and melon (Cucumis melo L.) fields from 2001 to 2005, no Q biotypes were detected. Regions of the United States that were severely impacted by the introduction of the B biotype of B. tabaci in the 1980s would be well advised to promote measures that limit movement of the Q biotype from controlled environments into field systems and to formulate alternatives for managing this multiply-resistant biotype, in the event that it becomes more widely distributed.     

Inheritance of resistance to pyriproxyfen in Bemisia tabaci (Hemiptera: Aleyrodidae) males and females (B biotype)

We evaluated effects of the insect growth regulator pyriproxyfen on Bemisia tabaci (Gennadius) (B biotype) (Hemiptera: Aleyrodidae) males and females in laboratory bioassays. Insects were treated with pyriproxyfen as either eggs or nymphs. In all tests, the LC50 for a laboratory-selected resistant strain was at least 620 times greater than for an unselected susceptible strain. When insects were treated as eggs, survival did not differ between males and females of either strain. When insects were treated as nymphs, survival did not differ between susceptible males and susceptible females, but resistant males had higher mortality than resistant females. The dominance of resistance decreased as pyriproxyfen concentration increased. Resistance was partially or completely dominant at the lowest concentration tested and completely recessive at the highest concentration tested. Hybrid female progeny from reciprocal crosses between the susceptible and resistant strains responded alike in bioassays; thus, maternal effects were not evident. Rapid evolution of resistance to pyriproxyfen could occur if individuals in field populations had resistance with traits similar to those of the laboratory-selected strain examined here.     

Specific binding of synthetic human pancreatic growth hormone releasing factor (1-40-OH) to bovine anterior pituitaries

We have studied the specific binding of a synthetic 40 amino acid, free carboxy terminus analog of human pancreatic growth hormone releasing factor (hp GRF-40-OH) to partially purified homogenates of bovine anterior pituitaries. The binding of hpGRF-40-OH to pituitary receptors at 4 degrees C reached maximal level in 4 hours and remained steady for the next 18 hours. Specific binding increased linearly with the amount of protein present in the assay. 125I-hpGRF-40-OH binding to pituitary homogenates was competitively inhibited by hpGRF-40-OH but not by unrelated hormones. The competition curve and Scatchard analysis suggest the presence of single class of receptors with a Kd congruent to 3nM and binding capacity of approximately 200 fmoles/mg protein. This is the first demonstration of specific receptors for GRF on anterior pituitary cells.     

Chromosomal Localization of the Human Genes for α1A, α1B, and α1E Voltage-Dependent Ca Channel Subunits

The α₁ subunit genes encoding voltage-dependent Ca²⁺ channels are members of a gene family. We have used human brain cDNA probes to localize the neuronal isoform genes CACNL1A4 (α_1A), CACNL1A5 (α_1B), and CACNL1A6 (α_1E) to 19p13, 9q34, and 1q25-q31, respectively, using fluorescence in situ hybridization on human chromosomes. These genes are particularly interesting gene candidates in the pathogenesis of neuronal disorders. Although genetic disorders have been linked to loci 9q34 and 19p13, no genetic disease related to Ca²⁺ signaling defects has yet been linked to these loci.     

Peripartum Cardiomyopathy Presenting With Ventricular Tachycardia: A Rare Presentation

A 25-year-old previously asymptomatic pregnant woman at 36 weeks'' gestation was noticed to have repetitive monomorphic ventricular tachycardia. A dilated left ventricle with moderately reduced systolic function was found on echocardiographic examination. This is a very rare presentation of peripartum cardiomyopathy (PPCMP) presenting with repetitive monomorphic ventricular tachycardia.     

The Genome Sequence DataBase: towards an integrated functional genomics resource.

During 1998 the primary focus of the Genome Sequence DataBase (GSDB; http://www.ncgr.org/gsdb ) located at the National Center for Genome Resources (NCGR) has been to improve data quality, improve data collections, and provide new methods and tools to access and analyze data. Data quality has been improved by extensive curation of certain data fields necessary for maintaining data collections and for using certain tools. Data quality has also been increased by improvements to the suite of programs that import data from the International Nucleotide Sequence Database Collaboration (IC). The Sequence Tag Alignment and Consensus Knowledgebase (STACK), a database of human expressed gene sequences developed by the South African National Bioinformatics Institute (SANBI), became available within the last year, allowing public access to this valuable resource of expressed sequences. Data access was improved by the addition of the Sequence Viewer, a platform-independent graphical viewer for GSDB sequence data. This tool has also been integrated with other searching and data retrieval tools. A BLAST homology search service was also made available, allowing researchers to search all of the data, including the unique data, that are available from GSDB. These improvements are designed to make GSDB more accessible to users, extend the rich searching capability already present in GSDB, and to facilitate the transition to an integrated system containing many different types of biological data.