A rapid and efficient one-tube PCR-based mutagenesis technique using Pfu DNA polymerase

A rapid method for efficiently generating site-directed mutations on a clean sequence background is described. This modification of the megaprimer PCR mutagenesis approach can be performed in one tube in less than 4.5 hours, and does not require purification of intermediate products. High fidelity of DNA sequence replication is obtained by employing Pfu DNA polymerase and limiting the total number of amplification cycles to 30. The mutagenesis efficiency of the procedure is high enough to allow rapid, direct identification of mutants by restriction digest or sequencing techniques.

Getting the most out of low-dose syringe prefilling of a high-cost biotechnology agent

The recent increased usage of high-cost biotechnology agents has placed a tremendous impact on the hospital pharmacy budget. One approach in improving cost containment is to minimize waste during the preparation of these agents. This is particularly practical and possible in the process of low-dose syringe repackaging of Sargramostim (GM-CSF) used for the treatment of neutropenia. In search of ways to reduce waste, this study looked into the dos and don'ts of repackaging this agent in syringes. Decreased waste is very significant if GM-CSF is properly reconstituted with bacteriostatic water for injection and if a syringe equipped with a permanently attached needle is used. Another 10% of the solution from each vial could be saved if the solution is withdrawn with a technique involving the vial in a right-side-up position.

Immediate-early baculovirus genes transactivate the p143 gene promoter of Autographa californica nuclear polyhedrosis virus

Trans-acting regulatory components of Autographa californica nuclear polyhedrosis virus (AcMNPV) were studied in a transient assay system for their ability to activate the p143 gene promoter. A region including 502 nt upstream of the AUG of the p143 gene was linked to the bacterial chloramphenicol acetyltransferase (CAT) gene. The p143 promoter-CAT construct was used to identify AcMNPV immediate-early gene products required for expression from the p143 gene early promoter. Transient expression assays in uninfected Spodoptera frugiperda cells indicated that the IE-1 gene product was capable of transactivating the p143 gene promoter and this activation was augmented by the IE-N gene product. In addition, another immediate-early gene, PE-38, was shown to mediate transactivation of the p143 gene promoter but not the 39K delayed early gene promoter. Deletions to -187 bp relative to the p143 RNA start site did not significantly affect promoter activity in the combined presence of IE-1 and the HindIII-F fragment. However, a deletion to -52 bp decreased promoter activity by 40%. In contrast, in the presence of ts8 DNA at 33 degrees, deletions to -52 bp decreased promoter activity by 80% suggesting that additional viral factors were involved in p143 gene promoter regulation.

Effects of pentoxifylline on sperm motility and hyperactivation in normozoospermic and normokinetic semen

OBJECTIVE

To determine the effects of in vitro incubation with pentoxifylline on sperm motion characteristics of spermatozoa from normozoospermic, normokinetic specimens.

DESIGN

Prospective, controlled experiment.

SETTING

Andrology laboratory, university-based fertility center.

PARTICIPANTS

Healthy, untreated male partners of couples attending the fertility center.

INTERVENTION

Each specimen was washed, pelleted by centrifugation, then resuspended in human tubal fluid medium (HTF). Two portions were incubated at 37 degrees C, one with pentoxifylline (final concentration = 1 mg/mL = 3.6 mM) and the other without pentoxifylline (control). After 1 hour, the pentoxifylline-treated portion was divided: one half was washed to remove pentoxifylline, then further incubated in HTF; the other half remained incubated in HTF with pentoxifylline.

MAIN OUTCOME MEASURES

Motility, hyperactivation, amplitude of lateral head displacement (ALH), curvilinear velocity (VCL), straight line velocity (VSL), linearity (LIN), beat-cross frequency.

RESULTS

Incubation with pentoxifylline did not increase motility, VSL, LIN, or beat-cross frequency but did significantly increase HA, VCL, and ALH at 1, 2, and 4 hours, compared with control. Incubation in control medium without pentoxifylline did not significantly increase any of the parameters measured. After 24 hours of incubation with or without pentoxifylline, all parameters measured were significantly decreased, with the exception of LIN.

CONCLUSIONS

Pentoxifylline does not increase percentage motility of washed spermatozoa in capacitation medium. Enhancement of sperm HA by pentoxifylline in capacitation medium occurs with normozoospermic, normokinetic semen specimens. This effect persists for up to 4 hours when pentoxifylline is removed from the medium after 1 hour of incubation.

The inhibitory effects of 21 mimics of superoxide dismutase on luminol-mediated chemiluminescence emitted from PMA-stimulated polymorphonuclear leukocyte

Four groups comprising 21 superoxide dismutase (SOD) mimics synthesized by us were comparatively studied for their inhibitory effects on luminol-mediated chemiluminescence emitted from phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocyte (PMNL). Among these groups, 20-membered macrocyclic bicopper(II) complexes and 13-membered macrocyclic dioxotetramine copper(II) complexes exhibited relatively higher activities of scavenging reactive oxygen species (ROS) produced by PMA-stimulated PMNL as compared with polyamine Cu(II)-Zn(II) complexes and copper(II) complexes of bis-shiff-base. Moreover, distinctly different effects of SOD mimics in the biological system have been found even in the same group. It is suggested that the biological effects of some SOD mimics are related to their structures.

Nucleotide sequence and transcriptional analysis of the p80 gene of Autographa californica nuclear polyhedrosis virus: a homologue of the Orgyia pseudotsugata nuclear polyhedrosis virus capsid-associated gene

The 67.2- to 68.5-m.u. region of Autographa californica nuclear polyhedrosis virus was sequenced. A large open reading frame (ORF) was identified in the clockwise direction on the circular genome map which could potentially encode an 80-kDa polypeptide. Analysis of the predicted amino acid sequence of this ORF indicated that it was a homologue of the p87 capsid-associated gene of Orgyia pseudotsugata MNPV with an overall amino acid similarity of 34.3%. A late transcript of 2.1 kb was mapped to this open reading frame. An antisense 3.1-kb transcript partially overlapped the 5' end of the 2.1-kb RNA. Anti-extracellular virus sera reacted with a fusion protein consisting of a portion of the AcMNPV p80 gene fused to the bacterial trpE gene product, suggesting that the AcMNPV p80 gene product was also a component of the virus capsid.

Silver-induced frog skeletal muscle contraction and its modulation by calcium antagonists nifedipine and felodipine and calcium agonist Bay K 8644

1. Ag+ induces one phase of a transient contracture in frog skeletal muscle (0.3-10 microM) and potentiates twitch tension when the fiber is given continuous stimulation. 2. The potentiation of fiber contraction by Ag+ is similar to the effect of Ca2+ antagonists nifedipine and felodipine. 3. Bay K 8644 (100 nM) potentiates and accelerates Ag(+)-induced tension development and the inactivation occurs more rapidly than in the control (Ag+ alone). 4. Two factors can be considered to be essential for the induction of Ag+ contracture: (1) a certain number of Ag+ ions must bind to free SH groups of the voltage sensor; and (2) the binding must occur within a limited time to raise the mechanical threshold to induce contracture. 5. All results suggest that Ag+ binding to crucial SH groups on the Ca2+ channel may be responsible for the activation of muscle contraction, potentiation, and the inhibition of excitation-contraction coupling in skeletal muscle.

[Chemical constituents of Actinidia kolomikta (Rupr. et Maxim.) Planch]

Two crystalline components I and II were isolated from the roots of Actinidia kolomikta. I was identified as delta 7-stigmasterol and II was named alpha-kolomiktriose and elucidated as 2, 3-di-0-beta-D-galactopyranosyl-alpha-D-galactopyranose on the basis of spectral data (13C NMR, 1H NMR, IR and EI-MS).

Transcription analysis of the EcoRI D region of the baculovirus Autographa californica nuclear polyhedrosis virus identifies an early 4-kilobase RNA encoding the essential p143 gene

We have investigated the transcriptional activity of the 60.1- to 68.3-map-unit region of the baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV). Twelve transcripts mapping to this region were expressed at various times during infection. An early 4.0-kb transcript, potentially coding for a 143-kDa peptide essential for viral DNA replication, was maximally abundant at 6 h postinfection (p.i.). Transcripts of 0.5, 1.1, 1.4, 2.1, and 3.1 kb were most abundant at 12 h p.i., while two large transcripts of 5.2 and 6.8 kb were expressed maximally at 24 h p.i. In the presence of cycloheximide, and in ts8-infected cells at the nonpermissive temperature, only the 4.0-kb RNA was expressed. Northern (RNA) blot analysis using DNA subfragments from the EcoRI D fragment as probes suggested that many of the transcripts overlapped. Strand-specific cRNA probes revealed that the majority of the RNAs were transcribed in the counterclockwise direction. S1 nuclease and primer extension analysis were used to map the 5' ends of transcripts coded within the 60.1- to 64.8-map-unit region. Mapping of the 3' ends of the 1.1-, 4.0-, 5.2-, and 6.8-kb transcripts suggested that these RNAs were all coterminal at their 3' ends. A minicistron was found between the early 4.0-kb transcription start site and the predicted ATG start codon of the p143 gene. Several similar sequence motifs were identified in the promoter regions of the p143 gene and the AcMNPV DNA polymerase gene.

Partial inhibition of skeletal muscle contraction by dantrolene sodium and its modification with perchlorate and Bay K 8644

The effects of dantrolene sodium (DAN) on the dihydropyridine receptor (DHPR) of the transverse (T) tubule voltage sensor (Ca2+ channel) was studied with single fibers from bullfrog toe muscle. Perchlorate (ClO4-), which acts selectively on the DHPR, overcame DAN-induced inhibition of twitch tension. Bay K 8644, a DHPR agonist, slowed the rate of twitch inhibition by DAN. DAN inhibited twitch tension to a greater extent in Ca(2+)-free solution than in Ringer solution or solution containing Zn2+, whereas twitch inhibition by DAN was less in caffeine-containing solution than in the control. The effects of DAN on Zn(2+)- and caffeine-treated fibers and on fibers in Ca(2+)-free solution suggest that DAN must act near the voltage sensor of the T tubule. However, differences in net twitch inhibition by DAN between control fibers and fibers potentiated by ClO4- or Bay K 8644 suggest that DAN does not bind to the same site as these potentiating agents do. The role of myoplasmic Ca2+ in DAN-induced inhibition of twitch and the effects of DAN on the mechanical threshold and membrane potential in skeletal muscle are discussed.

Nucleotide sequence and transcriptional analysis of the HindIII P region of a temperature-sensitive mutant of Autographa californica nuclear polyhedrosis virus

DNA sequence analysis of the HindIII P region of a temperature-sensitive mutant of Autographa californica nuclear polyhedrosis virus confirmed the specific amplification of 1.4 kb of viral DNA from this region of the genome. The sequenced region included an open reading frame, translated in a counterclockwise direction, which would potentially encode a 74K protein. The amplified DNA was contained within this open reading frame, resulting in in-frame amplifications of a domain within the protein. Transcription studies revealed the presence of a ladder of viral RNA species corresponding to a 2.5 kb transcript carrying tandem repeats of about 1.4 kb. This indicated that the duplicated DNA was transcribed in the same orientation as the p10 gene. We predict that transcripts synthesized from the opposite DNA strand also consist of a ladder of related mRNAs which would be translated to produce a family of p74 proteins with multiple internal domains.

Time-resolved pulsed fluorescence immunometric assays of carcinoembryonic antigen

A time-resolved pulsed fluorescence immunometric assay (TR-PFIA) for carcinoembryonic antigen is described in which either Eu(III) or Tb(III) chelate is used as label. Described in detail is the assay involving the well-documented format of microtiter matrix and Eu(III) fluorescence enhanced with a beta-diketone and quantified in a commercial time-resolving fluorometer. We have also used the same basic assay, but one with a Tb(III) chelate as label, and we read the fluorescence signal directly off a surface without the application of enhancement solution. The Tb(III) fluorescence is then brought into solution by using an analog of dipicolinic acid in an enhancement solution. The latter approach demonstrates the scope of the methodology, which invokes the extra complexity of enhancement only when increased sensitivity might be required. The power and versatility of the enhancement methodology are demonstrated.

Time-resolved pulsed fluorescence immunometric assays of carcinoembryonic antigen

A time-resolved pulsed fluorescence immunometric assay (TR-PFIA) for carcinoembryonic antigen is described in which either Eu(III) or Tb(III) chelate is used as label. Described in detail is the assay involving the well-documented format of microtiter matrix and Eu(III) fluorescence enhanced with a beta-diketone and quantified in a commercial time-resolving fluorometer. We have also used the same basic assay, but one with a Tb(III) chelate as label, and we read the fluorescence signal directly off a surface without the application of enhancement solution. The Tb(III) fluorescence is then brought into solution by using an analog of dipicolinic acid in an enhancement solution. The latter approach demonstrates the scope of the methodology, which invokes the extra complexity of enhancement only when increased sensitivity might be required. The power and versatility of the enhancement methodology are demonstrated.

Maternal corneal thickness during pregnancy

We measured central corneal thickness in 89 pregnant women. It was increased 16 micron (P = .01) compared to the control eyes of 18 nongravid and 17 postpartum women. There was no significant difference (P = .79) in corneal thickness between the nongravid and postpartum groups. When comparing subjects by week of gestation, there was no trend over time in corneal thickness (analysis by linear regression). Intraocular pressure was lowered during pregnancy, but it did not correlate with corneal thickness for either the pregnant or nonpregnant group.