ABSTRACT
OBJECTIVE: Non-squamous non-small cell lung cancer (NSCLC) is the first leading cause of cancer-related deaths in Taiwan. This study aimed at evaluating the effectiveness of first-line targeted therapy for advanced epidermal growth factor receptor (EGFR) mutation-positive non-squamous NSCLC in Taiwan. PATIENTS AND METHODS: This was a real-world, retrospective, observational study of patients diagnosed with advanced non-squamous NSCLC (N=63,248). Between 2011 and 2019, 19,458 patients received targeted therapy and 22,994 patients received chemotherapy alone; between 2002 and 2010, 20,796 patients received chemotherapy alone. Overall survival (OS) was determined. RESULTS: The median OS for patients treated with first-line targeted therapy (22.9 months) was longer than that of patients receiving chemotherapy alone (11.7 months). HR: 0.521, log-rank test, p<0.001. CONCLUSIONS: These data represent the potential survival outcomes of Taiwanese patients with advanced EGFR mutation-positive non-squamous NSCLC in clinical practice.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , Cohort Studies , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Retrospective Studies , ErbB Receptors/genetics , ErbB Receptors/therapeutic use , Mutation , Protein Kinase Inhibitors/therapeutic useABSTRACT
This prospective study assessed the outcome of percutaneous cannulated screw fixation in 49 of 60 acute scaphoid fractures. The union rate was 100% (mean time for radiological union at 12 weeks). There were no early or mid-term complications and all achieved an excellent functional recovery.
Subject(s)
Bone Screws , Fracture Fixation, Internal/methods , Fractures, Bone/surgery , Scaphoid Bone/injuries , Wrist Injuries/surgery , Adolescent , Adult , Female , Fractures, Bone/diagnostic imaging , Humans , Male , Prospective Studies , Radiography , Scaphoid Bone/diagnostic imaging , Treatment Outcome , Wrist Injuries/diagnostic imagingABSTRACT
Different regions of RF DNA from the filamentous bacteriophage phiLf were cloned in Escherichia coli vectors that can not be maintained in Xanthomonas. After introduction into X. campestris pv. campestris 17 (Xc17), most of these constructs were found to integrate into the host chromosome, either by recA-dependent homologous recombination or recA-independent site-specific integration. Mutations in himA, which codes for the alpha-subunit of the Integration Host Factor, does not affect the integration. Integration occurs into a chromosomal region which harbors a copy of a defective phage (4445 bp) that shares a high degree of identity with the phiLf genome. While various parts of the 4445-bp region are susceptible to homologous recombination, site-specific integration requires the attB sequence on the chromosome and the phage attP. The attB shows a high level of sequence identity (22 out of 28 bp) to the dif site required for E. coli Xer site-specific recombination, including the 6-bp central region, and 8/11 identity in both the left XerC-binding arm and the right XerD-binding arm, with the innermost 5 nt of the arms forming a dyad symmetry that is also present in dif. The attP has the same central region and shows 10/11 identity to the dif site in the left arm, but the sequence of the right arm is less conserved than that of attB. The smallest regions still capable of mediating integration are a cloned 72-bp phiLf attP-containing sequence and a 51-bp Xc17 attB-containing sequence, which was reinserted into the Xc17 chromosome after the 4445-bp region had been deleted, indicating that accessory sequences are not necessary and that the integrase required for site-specific integration is neither specified by the 4445-bp Xc17 chromosomal region nor encoded by the phiLf genome.
Subject(s)
Chromosomes/genetics , Genetic Vectors/genetics , Inovirus/genetics , Recombination, Genetic/genetics , Xanthomonas/genetics , Base Sequence , Chromosome Deletion , Escherichia coli/genetics , Molecular Sequence Data , Mutation , Plasmids , Restriction MappingABSTRACT
Secondary and tertiary structures in the 3' untranslated region (UTR) of plus-strand RNA viruses have been postulated to function as control elements in RNA replication, transcription, and translation. Here we describe a 54-nucleotide (nt) hairpin-type pseudoknot within the 288-nt 3' UTR of the bovine coronavirus genome and show by mutational analysis of both stems that the pseudoknotted structure is required for the replication of a defective interfering RNA genome. The pseudoknot is phylogenetically conserved among coronaviruses both in location and in shape but only partially in nucleotide sequence, and evolutionary covariation of bases to maintain G. U pairings indicates that it functions in the plus strand. RNase probing of synthetic transcripts provided additional evidence of its tertiary structure and also identified the possible existence of two conformational states. These results indicate that the 3' UTR pseudoknot is involved in coronavirus RNA replication and lead us to postulate that it functions as a regulatory control element.
Subject(s)
3' Untranslated Regions/genetics , Coronavirus/physiology , RNA, Viral/genetics , Virus Replication/genetics , Animals , Base Sequence , Cattle , Conserved Sequence , Molecular Sequence Data , Nucleic Acid Conformation , PhylogenyABSTRACT
BACKGROUND: Acardius is a rare occurrence in monozygotic multiple pregnancies. Triplet pregnancy composed of an acardiac fetus and a pair of conjoined twins is even more rare. The outcome of the acardius is invariably fatal, and the mortality rate of the other fetuses ranges between 50% and 70%. Perinatal mortality results mainly from complications of twin-twin transfusion syndrome. CASE: Intrauterine fetal death, caused by an umbilical cord accident, with twisting of the acardius's cord around the fused cords of conjoined twins is reported in this present work. CONCLUSION: An acardius should be thoroughly sought when monochorionic multiple pregnancies are found by ultrasound during prenatal care. The complications of pregnancy caused by an acardiac fetus can be avoided by using proper management.
Subject(s)
Fetal Death/etiology , Heart Defects, Congenital/complications , Triplets , Twins, Conjoined , Umbilical Cord , Adult , Female , Gestational Age , Heart Defects, Congenital/diagnostic imaging , Humans , Pregnancy , Radiography , Torsion Abnormality , Ultrasonography, Prenatal/methods , Umbilical Cord/pathologyABSTRACT
The 65-nucleotide leader on the cloned bovine coronavirus defective interfering (DI) RNA, when marked by mutations, has been shown to rapidly convert to the wild-type leader of the helper virus following DI RNA transfection into helper virus-infected cells. A model of leader-primed transcription in which free leader supplied in trans by the helper virus interacts by way of its flanking 5'UCUAAAC3' sequence element with the 3'-proximal 3'AGAUUUG5' promoter on the DI RNA minus strand to prime RNA replication has been used to explain this phenomenon. To test this model, the UCUAAAC element which occurs only once in the BCV 5' untranslated region was either deleted or completely substituted in input DI RNA template, and evidence of leader conversion was sought. In both cases, leader conversion occurred rapidly, indicating that this element is not required on input RNA for the conversion event. Substitution mutations mapped the crossover region to a 24-nucleotide segment that begins within the UCUAAAC sequence and extends downstream. Although structure probing of the bovine coronavirus 5' untranslated region indicated that the UCUAAAC element is in the loop of a prominent stem and thus theoretically available for base pair-directed priming, no evidence of an unattached leader early in infection that might have served as a primer for transcription was found by RNase protection studies. These results together suggest that leader conversion on the DI RNA 5' terminus is not guided by the UCUAAAC element and might arise instead from a high-frequency, region-specific, homologous recombination event perhaps during minus-strand synthesis rather than by leader priming during plus-strand synthesis.
Subject(s)
Coronavirus, Bovine/genetics , Defective Viruses/genetics , Promoter Regions, Genetic , RNA, Viral/biosynthesis , Recombination, Genetic , Animals , Base Composition , Base Sequence , Cattle , Cells, Cultured , DNA Primers , Helper Viruses/genetics , Models, Structural , Molecular Sequence Data , Mutagenesis, Site-Directed , Nucleic Acid Conformation , Polymerase Chain Reaction , RNA, Viral/genetics , Templates, Genetic , Transcription, Genetic , TransfectionABSTRACT
Double-chambered right ventricle is a rare congenital heart disease. Anomalous muscle bundles in the right ventricle divide the right ventricle into two portions and cause intracavitary obstruction of the right ventricle. Transesophageal echocardiography of the double-chambered right ventricle has never been reported. We present a 32-year-old man with double-chambered right ventricle associated with perimembranous-type ventricular septal defect and left superior vena cava. Multiplane transesophageal echocardiography provides excellent views of an anomalous muscle bundle in the right ventricle, which differed from a moderator band by its insertion site on the right ventricle.
Subject(s)
Echocardiography, Transesophageal , Heart Defects, Congenital/diagnostic imaging , Heart Ventricles/abnormalities , Adult , Echocardiography , Heart Septal Defects, Ventricular/diagnostic imaging , Hemodynamics/physiology , Humans , Male , Tricuspid Valve Insufficiency/diagnostic imagingABSTRACT
Insertion of the 17-nucleotide promoter region for the bovine coronavirus N gene as part of a 27-nucleotide cassette into the open reading frame of a cloned synthetic defective-interfering (DI) RNA resulted in synthesis of subDI RNA transcripts from the replicating DI RNA genome. Duplicating and triplicating the promoter sequence in tandem caused a progressive increase in the efficiency of subgenomic mRNA synthesis despite a concurrent decrease in the rate of DI RNA accumulation that was not specific to the promoter sequences being added. Although initiation of transcription (leader fusion) occurred at each of the three promoter sites in the tandem construct, almost all of the transcripts were found as a product of the most downstream (3'-most on the genome) promoter. These results show that enhancement of subgenomic mRNA synthesis is a property that can reside within sequence situated near the promoter. A possible role for the plus strand in the downstream promoter choice is suggested.
Subject(s)
Coronavirus, Bovine/genetics , Promoter Regions, Genetic/genetics , RNA, Messenger/biosynthesis , RNA, Viral/biosynthesis , Animals , Base Sequence , Capsid/genetics , Cattle , Genes, Reporter/genetics , Genome, Viral , Molecular Sequence Data , Murine hepatitis virus/genetics , RNA, Messenger/genetics , RNA, Viral/genetics , Sequence Analysis, DNA , Transcription, Genetic/genetics , Transmissible gastroenteritis virus/genetics , Viral Core Proteins/geneticsABSTRACT
A naturally occurring 2.2-kb defective interfering (DI) RNA of the bovine coronavirus, structurally a simple fusion of the genomic termini, contains a single contiguous open reading frame (ORF) or 1.7 kb composed of the 5'-terminal 288 nucleotides of polymerase gene 1a and all 1,344 nucleotides of the nucleocapsid protein (N) gene. The ORF must remain open throughout most of its sequence for replication to occur. To determine the qualitative importance of the N portion of the chimeric ORF in DI RNA replication, transcripts of mutated reporter-containing constructs were tested for replication in helper virus-infected cells. It was determined that the N ORF could not be replaced by the naturally occurring internal I protein ORF, accomplished by deleting the first base in the N start codon which leads to a +1 frameshift, nor could it be replaced by the chloramphenicol acetyltransferase ORF. Furthermore, 3'-terminal truncations of the N gene leaving less than 85% of its total length were likewise not tolerated. Small in-frame deletions and in-frame foreign sequence insertions of up to 99 nucleotides within certain regions of the N ORF were tolerated, however, but the rate of DI RNA accumulation in these cases was lower. These results indicate that there is a requirement for translation of most if not all of the N protein in cis for optimal replication of the bovine coronavirus DI RNA and suggest that a similar requirement may exist for viral genome replication.
Subject(s)
Coronavirus, Bovine/genetics , Defective Viruses/genetics , RNA, Viral/biosynthesis , Base Sequence , Capsid/genetics , Cell Line , Cloning, Molecular , Coronavirus, Bovine/physiology , DNA Repair , DNA-Directed DNA Polymerase/genetics , Defective Viruses/physiology , Molecular Sequence Data , Mutagenesis, Insertional , Oligodeoxyribonucleotides , Open Reading Frames , RNA, Viral/genetics , RNA, Viral/physiology , Sequence Deletion , Viral Core Proteins/genetics , Virus Replication/geneticsABSTRACT
Idiopathic dilatation of the pulmonary artery is an uncommon, but not rare, congenital anomaly that is diagnosed by exclusion and generally has a benign clinical course. A left hilar mass on the chest x-ray film is the major presentation. The authors present a case of idiopathic dilatation of the pulmonary artery with posttraumatic chest pain clinically. After serial examinations, idiopathic dilatation of the pulmonary artery was diagnosed. They discuss the phenomenon of transpulmonary valvular pressure gradient and noninvasive tools for long-term follow-up, including transesophageal echocardiography and magnetic resonance imaging.
Subject(s)
Pulmonary Artery/abnormalities , Diagnosis, Differential , Dilatation, Pathologic/diagnosis , Echocardiography, Transesophageal , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Pulmonary Artery/pathologyABSTRACT
Acute colonic ischemia is the most common form of intestinal ischemia. Nonocclusive ischemic colitis contributes to some of these disorders. Heart disease, such as congestive heart failure, myocardial infarction, arrhythmias, aortic valve disease, and atherosclerotic cardiovascular disease, account for many of its risk factors. The majority of cases are associated with severe congestive heart failure with low cardiac output, or disease states resulting in dehydration, or the splanchnic vasoconstrictive effect of some medications. Reactive splanchnic vasoconstriction is responsible for nonocclusive ischemic colitis. Ischemic colitis induced by a cleansing enema has been reported once before. The authors present a case of coronary artery disease complicated by colonic ischemia following glycerin enema in preparation for coronary bypass surgery. Reactive inferior mesenteric artery spasm in response to the enema was noted in this case, rather than diffuse mesenteric artery spasm in response to low cardiac output state and vasoconstrictive drugs.
Subject(s)
Colitis, Ischemic/etiology , Coronary Disease/surgery , Enema/adverse effects , Glycerol/adverse effects , Colitis, Ischemic/diagnostic imaging , Humans , Male , Middle Aged , Preoperative Care/adverse effects , RadiographyABSTRACT
A potential pseudoknot was found in the 3' untranslated region of the bovine coronavirus genome beginning 63 nt downstream from the stop codon of the N gene. Mutation analysis of the pseudoknot in a cloned defective interfering RNA indicated that this structural element is necessary for defective interfering RNA replication.
Subject(s)
Capsid/genetics , Coronavirus, Bovine/genetics , Genome, Viral , Nucleic Acid Conformation , RNA, Viral/biosynthesis , RNA, Viral/chemistry , Transcription, Genetic , Viral Core Proteins/genetics , Animals , Base Sequence , Cattle , Cloning, Molecular , Codon , Coronavirus, Bovine/metabolism , Defective Viruses/genetics , Defective Viruses/metabolism , Genes, Viral , Models, Structural , Molecular Sequence Data , Mutagenesis, Site-Directed , Polymerase Chain Reaction , Sequence Homology, Nucleic Acid , Transmissible gastroenteritis virus/geneticsABSTRACT
To test the hypothesis that the 65-nucleotide (nt) leader on subgenomic mRNAs suffices as a 5'-terminal cis-acting signal for RNA replication, a corollary to the notion that coronavirus mRNAs behave as replicons, synthetic RNA transcripts of a cloned, reporter-containing N mRNA (mRNA 7) of the bovine coronavirus with a precise 5' terminus and a 3' poly(A) of 68 nt were tested for replication after being transfected into helper virus-infected cells. No replication was observed, but synthetic transcripts of a cloned reporter-containing defective interfering (DI) RNA differing from the N mRNA construct by 433 nt of continuous 5'-proximal genomic sequence between the leader and the N open reading frame did replicate and become packaged, indicating the insufficiency of the leader alone as a 5' signal for replication of transfected RNA molecules. The leader was shown to be a necessary part of the cis-acting signal for DI RNA replication, however, since removal of terminal bases that destroyed a predicted intraleader stem-loop also destroyed replicating ability. Surprisingly, when the same stem-loop was disrupted by base substitutions, replication appeared only minimally impaired and the leader was found to have rapidly reverted to wild type during DI RNA replication, a phenomenon reminiscent of high-frequency leader switching in the mouse hepatitis coronavirus. These results suggest that once a minimal structural requirement for leader is fulfilled for initiation of DI RNA replication, the wild-type leader is strongly preferred for subsequent replication. They also demonstrate that, in contrast to reported natural mouse hepatitis coronavirus DI RNAs, the DI RNA of the bovine coronavirus does not require sequence elements originating from discontinuous downstream regions within the polymerase gene for replication or for packaging.
Subject(s)
Coronavirus, Bovine/genetics , Defective Viruses/genetics , Protein Sorting Signals/biosynthesis , RNA, Messenger/biosynthesis , RNA, Viral/biosynthesis , Amino Acid Sequence , Base Sequence , Calorimetry , Cell Line , Cloning, Molecular , Coronavirus, Bovine/metabolism , DNA Primers , Defective Viruses/metabolism , Humans , Molecular Sequence Data , Mutagenesis, Site-Directed , Nucleic Acid Conformation , Open Reading Frames , Polymerase Chain Reaction , RNA, Viral/chemistry , Rectal Neoplasms , Restriction Mapping , Transcription, Genetic , Transfection , Tumor Cells, CulturedABSTRACT
To study the neuromuscular interactions between succinylcholine (Sch) and esmolol, we determined the dose-response relationship of Sch and the neuromuscular actions of the 3xED90 dose of Sch, both prior to and following esmolol pretreatment. Twenty rats were anaesthetized with urethane. Train-of-four stimulation was applied every 12 s to the sciatic nerve, and the electromyogram (EMG) of the tibialis anterior muscle was measured. The results showed that the potency of Sch decreased with esmolol pretreatment. The ED50 of Sch increased significantly, from 191 ug/kg to 227 ug/kg after esmolol infusion, p < 0.05. The duration of EMG depression achieved by the 3xED90 dose of Sch decreased significantly with esmolol pretreatment (12 min vs 14 min p < 0.05), and also the onset time was significantly longer (43 sec vs 28 sec, p < 0.05). There were no significant difference between groups with regard to the maximal block or recovery index. The results of two methods of study demonstrated that the pharmacological interaction between Sch and esmolol is antagonistic instead of potentiating.
Subject(s)
Adrenergic beta-Antagonists/pharmacology , Muscle, Skeletal/drug effects , Propanolamines/pharmacology , Sciatic Nerve/drug effects , Succinylcholine/pharmacology , Animals , Drug Interactions , Male , Rats , Rats, Sprague-Dawley , Succinylcholine/antagonists & inhibitorsABSTRACT
Coronavirus subgenomic minus-strand RNAs (negative-strand copies of the 3' coterminal subgenomic mRNAs) probably function in mRNA amplification by serving as templates for transcription from internal (intergenic) promoters, rather than by faithful (full-length) mRNA replication.
Subject(s)
Coronavirus, Bovine/growth & development , RNA, Messenger/metabolism , RNA, Viral/metabolism , Base Sequence , Cells, Cultured , Coronavirus, Bovine/genetics , Defective Viruses/genetics , Models, Genetic , Molecular Sequence Data , Promoter Regions, Genetic/genetics , Transcription, Genetic , Virus Replication/geneticsABSTRACT
Transposable elements randomly insert into a targeted locus at a frequency of 10(-6) to 10(-5). The En element has been shown in previous studies to transpose more frequently into closely linked sites. Thus, it is appropriate to place an En element onto each of the 20 chromosome arms in maize to maximize tagging efficiency. This is called chromosome labeling for tagging purposes with transposons. After a chromosome arm has been labeled with a transposon, genes residing in that arm will have a greater chance to be tagged by the transposon. To date, all of the maize chromosome arms have been labeled with at least one of five Encontaining alleles. The elements were linked to the arms using reciprocal translocations. The usage of these arm-labeled lines is discussed in the context of gene tagging.
ABSTRACT
The common leader sequence on bovine coronavirus subgenomic mRNAs and genome was determined. To examine leader-mRNA junction sequences on subgenomic mRNAs, specific oligodeoxynucleotide sets were used in a polymerase chain reaction to amplify junction sequences from either the positive-strand mRNA (eight of nine total identified species) or the negative-strand anti-mRNA (six of the nine species), and sequenced. The mRNA species studied were those for the N, M, S, and HE structural proteins and the 9.5-, 12.7-, 4.8-, and 4.9-kDa putative nonstructural proteins. By defining the leader-mRNA junction sequence as the sequence between (i) the point of mismatch between the leader and genome and (ii) the 3' end of the consensus heptameric intergenic sequence [(U/A)C(U/C)AAAC)], or its variant, a unique junction sequence was found for each subgenomic mRNA species studied. In one instance (mRNA for the 12.7-kDa protein) the predicted intergenic sequence UCCAAAC was not part of the junction region, and in its place was the nonconforming sequence GGTAGAC that occurs just 15 nt downstream in the genome. Leader-mRNA junction sequences found after 296 days of persistent infection were the same as those found during acute infection (< 18 hr postinfection). These data indicate that, in contrast to the closely related mouse hepatitis virus, the bovine coronavirus maintains a stable leader-mRNA junction sequence for each mRNA. Interestingly, this stability may be related to the fact that a UCUAA sequence element, postulated by others to be a regulator of the leader-mRNA fusion event, occurs only once within the 3' flanking sequence of the genomic leader donor and once at intergenic sites in the bovine coronavirus genome, whereas it occurs two to four times at these sites in the mouse hepatitis coronavirus.
Subject(s)
Coronaviridae/genetics , RNA, Messenger/genetics , RNA, Viral/genetics , Animals , Base Sequence , Cattle , Coronaviridae/physiology , DNA, Viral , Genome, Viral , Humans , Molecular Sequence Data , Polymerase Chain Reaction , Tumor Cells, Cultured , Virus Replication/geneticsABSTRACT
The purpose of this study was to compare the effects of preoperative and postoperative iliohypogastric ilioinguinal nerve block (IINB) performed on 30 pediatric patients having elective unilateral herniorrhaphy for postoperative pain control and to discuss the theory of post-injury hypersensitivity of the nerves system. The patients were assigned into two groups (A = 15, B = 15) randomly. Both groups were given GA during the surgical procedure except that group A received IINB 15 minutes prior to skin incision and group B immediately after skin closure. The local anesthetic used was 0.25% bupivacaine and the dosage was 1 mg/Kg. The heart rate, BP, and anesthetic concentration (halothane) were recorded during the procedure and postoperative pain was assessed by using the modification of the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) behavior pain score which were taken at 1 hr, 3 hr (POR), 6 hr, and 24 hr (ward) postoperatively. Group A had less pain at 1 hr and 3 hr than group B postoperatively and is statistically significant. There was no statistically significant in pain score at 6 hr and 24 hr between the two groups.
Subject(s)
Hernia, Inguinal/surgery , Nerve Block , Pain, Postoperative/prevention & control , Adolescent , Buttocks/innervation , Child , Child, Preschool , Female , Humans , Male , Postoperative Care , Preoperative Care , Scrotum/innervationABSTRACT
430 apparently healthy subjects were studied with color Doppler flow imaging system. There were 216 females and 214 males, their age ranged from 4-80 years (mean 41.2 years). They were divided into 6 groups by every ten years of age, with group I having age below 19 and group VI age above 70. None of the subjects had previous diagnosis of cardiovascular diseases. Mitral regurgitation was detected in 30.9-52.8% in all the groups except group I, in which it was found in 20.0% only. The prevalence rate of tricuspid regurgitation was 9.8-36% in the six groups. Pulmonary regurgitation signals were detected in 43.8-4.8% in these groups with a tendency of lower incidence in the elderly. Aortic regurgitation were detected only in the three elder groups with an incidence of 5.5% in group 4 and 13.6% in group 6. The reason for that may be the degeneration of aortic valve with aging. Our study showed that in a large proportion of normal persons color Doppler echocardiography allows recording of regurgitation signals behind cardiac valves except for aortic valve. The regurgitation volume was small and there was no significant hemodynamic effect. The size and diameter of the heart chambers were normal when compared with other studies.
Subject(s)
Echocardiography, Doppler , Heart Valves/diagnostic imaging , Adolescent , Adult , Aged , Aged, 80 and over , Blood Circulation , Child , Female , Heart Valves/physiology , Humans , Male , Middle AgedABSTRACT
A filamentous phage, phi Lf, which specifically infects Xanthomonas campestris pv. campestris was isolated. The phage particle measured 1,000 (+/- 200) x 8 nm. It formed turbid plaques of about 1 mm in diameter. During multiplication, the progeny virions extruded into the medium without retarding host cell growth. Stocks were stable for 6 months at 4 degrees C and survived treatment at 80 degrees C for 10 min. Treatment with chloroform, ethanol or acetone completely destroyed infectivity; ethyl ether and methanol inactivated 98 to 99% of the phage. SDS-polyacrylamide gel electrophoresis showed a major coat protein band of approximate Mr 4000 whereas an immunoprecipitation test detected the existence of two coat protein species. The phage genome was shown to be a single-stranded DNA molecule. A physical map was constructed and the DNA size was calculated to be 5.9 kb. Cells treated with Tris-HCl containing CaCl2 and polyethylene glycol 6000 were transfected by replicative form DNA at a frequency of 3.4 x 10(3) p.f.u./micrograms.