Genetic Recombination of Transforming Deoxyribonucleic Acid Molecules with the Recipient Genome and Among Themselves in Protoplasts of Bacillus subtilis

Hirokawa, Hideo (Southwest Center for Advanced Studies, Dallas, Tex.), and Yonosuke Ikeda. Genetic recombination of transforming deoxyribonucleic acid molecules with the recipient genome and among themselves in protoplasts of Bacillus subtilis. J. Bacteriol. 92:455-463. 1966.-Re-extraction of transforming deoxyribonucleic acid (DNA) from protoplasts of Bacillus subtilis is much more efficient than from intact competent cells. This facilitated the detection of physical recombination between donor and recipient DNA molecules, as indicated by a high cotransfer index of ind(+) and his(+) markers which were originally located in exogenous and endogenous DNA molecules, respectively. This recombinant DNA was extracted after 30 min of incubation of ind his(+) protoplasts with ind(+)his DNA, previously extracted from a corresponding mutant strain of B. subtilis. The intracellular formation of recombinant molecules (ind(+)his(+)) bearing markers from two different exogenous DNA species was also detected 15 min after exposure of ind his recipient protoplasts to a mixture of ind(+)his and ind his(+) donor DNA molecules. The unity of the recombinant molecule was ascertained by dilution experiments and by its being resistant to ribonuclease and trypsin treatment (but being sensitive to deoxyribonuclease). The formation of recombinant molecules showed an inverse kinetics to that of the intracellularly induced loss of linkage between the corresponding markers in the wild-type DNA, thus suggesting a breakage and reunion process which is also favored by the absence of DNA synthesis in the protoplasts and the effect of some specific inhibitors.

d‐penicillamine‐induced pemphigus successfully treated with combination therapy of mizoribine and prednisolone

A 63-year-old woman had D-penicillamine-induced pemphigus with a high index value of circulating autoantibodies against desmoglein 1. Because of the lack of response to prednisolone monotherapy, the patient was treated with a combination therapy of mizoribine and low-dose prednisolone. The skin eruption was improved by this combination with a declined value of circulating anti-desmoglein 1 antibody. Currently, a remission of 2 months has been achieved, and prednisolone could be tapered.

Fibrocartilaginous embolism in a chondrodystrophoid breed dog

An 8-year-old intact male Shih Tzu dog was admitted with acute-onset tetraplegia. Magnetic resonance imaging showed an abnormality of the cervical intramedullary spinal cord. Histopathological examination of a spinal biopsy confirmed the presence of intravascular cartilaginous emboli. This is the first report of an antemortem diagnosis of fibrocartilaginous embolism in a chondrodystrophoid breed dog.

Proteus syndrome

A case of Proteus syndrome is presented, in which severe hemihypertrophy of the left trunk and left lower extremity, scoliosis, endometriosis and huge bizarre-shaped body tumors were observed. Up to 22.6 kg of tumorous tissue was excised. This syndrome was first described in 1983. The name Proteus comes from a Greek mythical sea god who was able to change his body form freely. This syndrome has numerous features including hemihypertrophy, macrodactyly, various subcutaneous masses, scoliosis and other minor abnormalities. Although diagnostic criteria have been established for Proteus syndrome, which is very difficult to differentiate from other congenital hamartomatous syndromes, more case reports are needed to define such a rare disorder. Our patient is the 6th Japanese case in the English literature.

[Immunohistochemical study of idiopathic and secondary epiretinal membrane]

PURPOSE

We investigated the immunohistochemical features of surgically resected idiopathic epiretinal membranes(ERMs) and secondary ERMs with regard to posterior vitreous detachment(PVD).

METHODS

Six specimens of idiopathic epiretinal membranes(3 eyes with complete PVD, 2 eyes with partial PVD, and one eye with no PVD) and 3 specimens of secondary ERMs(all eyes with complete PVD) were immunohistochemically studied. We used type I, II, III, IV collagen and fibronectin to study extracellular components, and glial fibrillary acidic protein(GFAP), S 100 protein, vimentin, and so forth to study cellular components.

RESULTS

All the specimens of idiopathic ERMs had the major components of the lamellar stained by type II collagen antibody, and one out of 3 specimens of secondary ERMs had a minor component stained by type II collagen antibody. Compared with idiopathic ERMs with complete PVD, 2 out of 3 specimens of idiopathic ERMs with partial PVD or no PVD contained rather thick collagen lamellar.

CONCLUSION

There was difference between specimens of idiopathic ERMs and specimens of secondary ERMs in staining by type II collagen antibody, supposed by vitreous, in this study. Idiopathic ERM with attached posterior vitreous membrane may cause growth of collagen.

Two novel glucose-6-phosphate dehydrogenase variants found in newborn mass-screening for galactosaemia

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive disorder in which haemolytic anaemia is the major symptom. The Beutler spot test employed in mass-screening for galactosaemia in newborns requires several intrinsic erythrocyte enzymes such as G6PD for its reaction and can theoretically detect G6PD deficiency apart from galactose-1-phosphate uridyltransferase deficiency. In this study, we detected two patients with G6PD deficiency using the quantitative Beutler test which was recently developed in our laboratory. Both patients lacked erythrocyte G6PD activity but exhibited no clinical symptoms. Molecular analysis in patients 1 and 2 revealed two novel missense mutations of C853T causing R285C and A1220C causing K407T, respectively. Molecular rather than enzymatic analysis was required in familial studies to detect and diagnose the carrier state. To date these patients have avoided oxidant stress and haemolytic diatheses have not been induced.

CONCLUSION

Our results indicate that the quantitative Beutler test can detect glucose-6-phosphate dehydrogenase deficiency of class 1 and 2 and is therefore useful for early intervention and prevention of haemolytic diathesis in patients with this disorder.

Analysis of radiation damage of DNA by atomic force microscopy in comparison with agarose gel electrophoresis studies

DNA damage induced with ionizing radiation is considered one of the main causes of cell inactivation. Several methods including gel electrophoresis, pulsed-field gel electrophoresis, neutral filter elution method, neutral sedimentation and electron microscopy have been applied to analyze this type of DNA damage. A new method employing an atomic force microscope (AFM) for nanometer-level-structure analysis of DNA damage induced with gamma-irradiation is introduced in this report. Structural changes of plasmid DNA on a molecular size scale of about 3 kbp were visually analyzed by AFM after irradiation with 60Co gamma-rays at doses of 1.9, 5.6, and 8.3 kGy. Three forms of plasmid DNA, closed circular (intact DNA), open circular (DNA with a single strand break) and linear form (DNA with a double strand break) were visualized by dynamic force mode AFM after gamma-irradiation. The torsional feature of the plasmid DNA was visualized better with AFM than with a transmission electron microscope (TEM). All three forms of plasmid DNA were observed in the sample irradiated with gamma-rays at the dose of 1.9 kGy. Open circular and linear forms were observed in the samples irradiated with gamma-rays at doses of 5.6 and 8.3 kGy, though no closed circular form was observed. A shortening of the length of a linear form of DNA irradiated with 5.6 and 8.3 kGy gamma-rays was observed by AFM. Structural changes of DNA after gamma-irradiation were visualized by AFM at nanometer level resolution. In addition, shortening of the length of the linear form of DNA after radiation exposure was observed by AFM.

Acute relapsing encephalopathy mimicking acute necrotizing encephalopathy in a 4-year-old boy

A 4-year-old boy showed two episodes of encephalitis/encephalopathy involving disturbed consciousness, convulsion, and paresis associated with the elevated levels of protein and myelin basic protein of the cerebrospinal fluid. MRI studies of the brain revealed symmetrical lesions in the brain stem and thalami at the first episode, and additional lesions were found in the cerebellum involving both the gray and white matter in the second episode. The intensities of MRI lesions were low in T I and high in T2. These episodes were followed by an elevation of the anti-viral antibody titers, for influenza A virus during the first episode and for adenovirus during the second. In the second episode, intravenous methylprednisolone therapy resulted in rapid improvement of his neurological signs.

Molecular basis for phenotypic heterogeneity in galactosaemia: prediction of clinical phenotype from genotype in Japanese patients

We identified 14 mutations in 15 Japanese subjects from 13 families with galactose-1-phosphate uridyltransferase (GALT) deficiency using denaturing gradient gel electrophoresis (DGGE) and direct sequence analysis. These mutations accounted for 22 (96%) of 23 mutant alleles in 15 Japanese subjects. The mutational spectrum included nine missense mutations (M142V, G179D, A199T, R231H, W249R, N314D, P325L, R333Q, and R333W), two deletions (L275fsdelT and Q317fsdelC), a nonsense mutation (W249X), and two splicing mutations (V85-N97fsdel38bp and IVS4nt+1). Ten of the 14 mutations have not been reported in Caucasians. Differences in frequency and spectrum of GALT mutations suggest that the mutations may have occurred after racial divergence of Caucasians and Asians. The Duarte variant in Japanese was associated with the N314D mutation, g.1105G > C, g.1323G > A, and g.1391G > A (SacI -) polymorphisms, as in Caucasians. The Duarte variant may have occurred before racial divergence, and was an ancient mutation. In vitro GALT activities of nine missense mutations were determined by a COS cell expression system, and indicated between 1.3% and 35% of wild-type control. Patients with R333Q (29% in vitro GALT activity) or A199T (35%) showed mild clinical phenotypes, i.e. no ovarian failure or neurological deterioration. Genotype determination is useful for predicting biochemical and clinical phenotypes in classic galactosaemia, and can be of further help in managing patients with this disorder.

[Telemedicine and telescience in the field of ophthalmology at Asahikawa Medical College]

Department of Ophthalmology at Asahikawa Medical University has established a video conferencing telemedicine network system between the department and each branch hospital in Japan to transmit full-motion (30 frames/second) color ophthalmological images since October 1994. Nowadays, the department has 15 branches to communicate with our system including one hospital in Fukushima Prefecture; Department of Ophthalmology, Harvard Medical School in USA; Nanjing Medical University in China with the use of INS net 1500 or INS net 64 (3 lines). This system is aimed for telemedicine, telescience as well as supports for ophthalmological surgeries. In this article, we described the present status and future prospective of our telemedicine project for the purpose of the elimination of areas without enough medical facilities and promotion of international scientific collaboration. We also described our "Telemedicine Center" at Asahikawa Medical University which is now under construction. We believe that this technology literally opens up the world to scientific and medical collaboration.

Oral fluorescein angiography with the confocal scanning laser ophthalmoscope

OBJECTIVE

To evaluate the efficacy of oral fluorescein angiography with a confocal scanning laser ophthalmoscope (SLO) system.

DESIGN

Comparative case series.

PARTICIPANTS

The authors used a confocal SLO (Heidelberg Retina Angiograph [HRA]) to perform oral fluorescein angiography in 47 patients, 13 of whom were without any retinal disease and 34 with a variety of retinal diseases including macular holes and pucker, inflammatory diseases, retinal vascular diseases, and age-related macular degeneration. The images were also compared to images taken with a fundus camera after intravenous fluorescein injections in patients on whom both studies were done.

INTERVENTION

Color fundus photographs were taken of each eye (30 degrees fundus camera) before drinking 4 ml of 25% sodium fluorescein mixed with 60 ml of orange juice. After oral fluorescein ingestion, images of each eye were taken with a fundus camera (TriX film) and the HRA (using 512- x 512-pixel resolution). The images were repeated at 0-, 2.5-, 5-, 7.5-, 10-, 12.5-, 15-, 20-, 25-, and 30-minute intervals. Twenty of the 47 patients underwent intravenous fluorescein angiography performed with the fundus camera.

MAIN OUTCOME MEASURE

Images were analyzed by a masked reader, and foveal avascular zone visualization, branch retinal vessel identification, and image quality were scored. Statistical analysis was performed with a t test for paired data with a two-tailed test of significance (alpha = 0.05).

RESULTS

Foveal avascular zone was 100% as seen in 16 eyes (47%) in the HRA machine versus 1 eye (2%) in the conventional fundus camera (P < 0.0001). The third-order branch retinal vessels were identified in 59% of eyes in the HRA versus 26% in the fundus camera group (P < 0.0001), and the image quality was considered comparable to an intravenous angiogram in 47% with the HRA versus 9% with the conventional fundus camera (P < 0.0001).

CONCLUSIONS

Oral fluorescein angiography using the HRA produces sufficiently detailed images to diagnose, treat, and follow many types of retinal pathology.

Comparison of short- and long-term effects of betaxolol and timolol on human retinal circulation

PURPOSE

To determine the short- and long-term effects of betaxolol and timolol on human retinal circulation.

METHODS

In a double-masked, randomised, placebo-controlled study we evaluated the effects of both a one-drop application and a twice-daily 2-week application of either topical 0.5% betaxolol hydrochloride or topical 0.5% timolol maleate on the retinal circulation in 12 healthy volunteers. Laser Doppler velocimetry was used to detect changes in the retinal venous blood flow.

RESULTS

In both betaxolol- and timolol-treated eyes, intraocular pressure decreased significantly compared with baseline values after both 90 min and 2 weeks. In betaxolol-treated eyes, retinal blood flow did not change significantly after 90 min, but increased significantly (14 +/- 9%; p = 0.02) compared with baseline after 2 weeks. In timolol-treated eyes, retinal blood flow decreased significantly (18 +/- 5%: p = 0.04) compared with baseline after 90 min, and also decreased significantly (14 +/- 6%; p = 0.04) compared with baseline after 2 weeks.

CONCLUSIONS

Retinal blood flow increases as a long-term effect of betaxolol and decreases as both a short- and long-term effects of timolol.

Gene 1, one of the dna genes of bacteriophage phi 29, represses other dna genes through binding to mRNA

The dna genes, essential for protein priming DNA replication of bacteriophage phi 29, are transcribed as a long polycistronic mRNA. In the previous study, gene 1 product (gp1) was shown to repress the expression of the upstream dna genes for DNA polymerase and primer protein. To investigate the details of the repression by gp1, we have examined the amount and integrity of polycistronic mRNA encoding DNA polymerase and primer protein by agarose gel electrophoresis and nuclease S1 protection assay. As a result, the amount, size, and integrity of the polycistronic mRNA were not influenced by the presence of gene 1. Furthermore, the RNA binding ability of gp1 was demonstrated by in vitro system using histidine-tagged gp1. These results strongly suggested that translation of the dna genes was affected by gp1 through binding to mRNA. Other possible mechanisms of gene regulation by gp1 were discussed.

Abnormal vitreous structure in optic nerve pit

A 37-year-old man presented with an optic nerve pit and serous macular detachment of the left eye. Scanning laser ophthalmoscopy revealed a cyst-like structure terminating at the pit in the premacular vitreous. During ocular movement, this structure moved vigorously and seemed to exert traction on the pit. We believe that it is part of an anomalous Cloquet's canal, and that traction on the pit may be a significant factor in the development of serous macular detachment in this patient.

[Cousins with X-linked recessive myotubular myopathy]

We describe two cousins with severe infantile form of myotubular myopathy. In Japan this disease has previously been reported in only three families. Case 1. The propositus, a 2-year-5-month-old boy, had been on a respirator since birth. He had a history of severe neonatal asphyxia and sequential hypotonia with dyspnea. Findings diagnostic of congenital myotubular myopathy, such as central nuclei and peripheral halo of muscle fibers, were demonstrated in his biopsied muscle. Case 2. A male the cousin of case 1 had congenital myopathy and died at 3 months of age due to respiratory failure. His muscle biopsy disclosed the identical findings as had been seen in case 1. These two cases were born to twin mothers, suggesting X-linked recessive inheritance. Early diagnosis and proper treatment of myotubular myopathy are important, because this condition may be erroneously-interpreted as the sequelae of neonatal asphyxia.

Variations of posterior vitreous detachment

AIMS

To identify variations in posterior vitreous detachment (PVD) and establish a clinical classification system for PVD.

METHODS

400 consecutive eyes were examined using biomicroscopy and vitreous photography and classified the PVD variations-complete PVD with collapse, complete PVD without collapse, partial PVD with thickened posterior vitreous cortex (TPVC), or partial PVD without TPVC.

RESULTS

In each PVD type, the most frequently seen ocular pathologies were as follows: in complete PVD with collapse (186 eyes), age related changes without vitreoretinal diseases (77 eyes, 41.4%) and high myopia (55 eyes, 29.6%); in complete PVD without collapse (39 eyes), uveitis (23 eyes, 59.0%) and central retinal vein occlusions (8 eyes, 20.5%); in partial PVD with TPVC (64 eyes), proliferative diabetic retinopathy (30 eyes, 46.9%); and inpartial PVD without TPVC (111 eyes), age related changes without vitreoretinal diseases (62 eyes, 55.9%). This PVD categorisation was significantly associated with the prevalence of each vitreoretinal disease (p < 0.0001, chi 2 test on contingency table).

CONCLUSIONS

PVD variations can be classified into four types, which is clinically useful because each type corresponds well to specific vitreoretinal changes.

Electron microscopy of biological specimens by the plasma-polymerization rapid-freeze replica method

The plasma-polymerization replica method is a unique replica technique for transmission electron microscopy. In the present study, we used this method in combination with a rapid-freeze technique to observe T4 bacteriophages and hepatitis B virus core particles. The heads of T4 bacteriophages appeared hexagonal and measured approximately 110 nm in length. Striations in their tails were also visible, indicating that the resolution of the present method is better than 4 nm. The images corresponded well with those obtained by ice-embedding and negative staining methods, with respect to both morphology and size of the phage particle. Hepatitis B virus core particles observed by the present method appeared round, approximately 30 nm in diameter, with hollow centres. Again, the morphology and size of the particles corresponded well with those obtained by ice-embedding, negative staining, and ultrathin sectioning. From these results, we conclude that the plasma-polymerization rapid-freeze replica method provides a useful technique for observation of biological specimens in a natural state and at high resolution.

[Biomicroscopic findings of premacular posterior vitreous]

The presence of vitreous gel in front of the macular area is still controversial. In order to understand the anatomy of the premacular vitreous, the posterior vitreous was observed biomicroscopically and slit-lamp photographs were taken in 100 eyes without posterior vitreous detachment. We defined the premacular vitreous as the lacuna seen when optically empty space, a demarcated oval shaped dark area without Tyndall phenomenon, was observed in front of the macula. Although the premacular vitreous showed liquefaction, the Tyndall-phenomenon, indicating the presence of formed vitreous gel, was observed in most cases. Premacular lacuna was observed in 3 cases with high myopia, and in one case with vitreoretinal degeneration syndrome. The bursa premacularis or premacular precortical vitreous pocket observed in autopsy eyes could barely be observed in living eyes.

Comparison of the prevalence of posterior vitreous detachment in whites and Japanese

The vitreous condition of healthy white (n = 551) and Japanese (n = 528) eyes were reviewed and compared with respect to the prevalence of posterior vitreous detachment (PVD) in the two groups. No white or Japanese patient 39 years of age or younger had PVD; the prevalence among those older than 39 increased with age in the fifth through the ninth decades, i.e., respectively, to 4%, 24%, 37% 59%, and 87% in the whites, and to 5%, 21%, 43%, 72%, and 82% in the Japanese. In none of these decades was there any significant difference between the prevalence of complete or partial PVD in the whites and the Japanese. This finding is significant because the vitreoretinal relationship influences the development and prognoses of the various vitreoretinal disorders.

Biomicroscopic vitreous videography

PURPOSE

The authors report on the technique of biomicroscopic vitreous videography using the recently developed charge coupled device (CCD) video camera.

METHODS

The authors performed biomicroscopic vitreous videography using the CCD video camera connected to a slit-lamp biomicroscope to examine 50 eyes with age- or disease-related vitreous changes in 50 patients. The cases were categorized as follows: 20 normal senile eyes; 10 eyes with retinal breaks; 10 eyes with diabetic retinopathy; 5 eyes with uveitis; and 5 eyes with high myopia. Noncontact positive preset lenses were used for observing the posterior vitreous; a wide-angle funduscopic contact lens and a three-mirror contact lens were used to observe the peripheral vitreoretinal changes.

RESULTS

Using the CCD video camera, dynamic vitreous changes were documented clearly using real-time television monitoring. The video system also allowed rapid review of the vitreous changes.

CONCLUSION

This new biomicroscopic vitreous videography system will contribute to the study of vitreoretinal diseases and be valuable as an educational tool.

Bending of DNA in solution caused by a protein from Arabidopsis that binds to a TATA element

The TFIID complex, which is a general transcription factor, helps to activate and regulate the transcription associated with eukaryotic promoters. A TATA element-binding protein (TBP), a central subunit of the TFIID complex, binds to TATA elements. Circular permutation analysis showed that purified recombinant TBP-1 from Arabidopsis (aTBP-1) introduced a bend in DNA around a TATA element in DNA fragments in solution. The bending was a slow process. A bend in DNA caused by a TBP-1 was seen under an electron microscope, as was an aTBP-DNA complex after immunochemical staining.

Multiple DNA conformational changes induced by an initiator protein precede the nicking reaction in a rolling circle replication origin

The core origin for plus strand DNA replication of filamentous bacteriophage f1 binds the initiator protein (gpII), which subsequently introduces a specific nick in the plus strand. The core origin consists of a nicking region and a binding region. The binding of gpII occurs in two steps, forming a binding intermediate (complex I) and a functional complex for nicking (complex II). Results of gel retardation experiments using circularly permuted DNA fragments and direct visualization by electron microscopy show that gpII induces successive bends within the binding region upon formation of the complexes. We show that gpII binding induces duplex melting in the nicking region using KMnO4 modification of unpaired thymidine residues as a probe for melting. Origin binding occurred in the absence of superhelicity of DNA and Mg2+, whereas duplex melting required superhelical DNA, but not Mg2+. Deletion analyses indicated that hypothetical formation of a cruciform around the nicking site is not necessary for either melting or nicking. A mutation in gpII resulted in stimulation of duplex melting and nicking without showing obvious effects on bending. This suggests that the mechanism of melting involves local interaction between gpII and the nicking region. Furthermore, using synthetic oligonucleotide substrates, we show that the nicking reaction takes place efficiently when the nicking region is single-stranded and the binding region is double-stranded. These results indicate that the nicking reaction is preceded by an ordered series of protein-induced DNA-conformational changes: successive bending of the origin upon gpII binding, followed by duplex melting that requires negative superhelicity.

[The difference between right and left in vitreous findings of normal eyes]

The vitreous in both normal eyes of 671 normal subjects was studied biomicroscopically. The results obtained were as follows: 1. In 618 cases of a refractive error less than -3D (group A) and 53 cases of refractive error over -3D (group B), the incidence of posterior vitreous detachment (PVD) in both eyes increased with age and the absence of PVD in both eyes decreased with age. The percentage of cases with PVD in one eye and no PVD in the other eye was less than 22% in all age groups. 2. There was no significant difference in the degree of vitreous liquefaction between the right and the left eyes. The degree of vitreous liquefaction was also age-related. 3. In the cases with PVD in one eye and no PVD in the other eye, a higher incidence of mild vitreous liquefaction was found in group A than in group B. 4. PVD without collapsed vitreous (simple PVD) in both eyes was observed only in group A. 5. Our results indicated that the vitreous findings in both eyes of an individual were almost identical, and PVD may occur with less vitreous liquefaction in group A than in group B.

Complementation assay of primer protein: gene expression systems of plasmid vectors support the infection of suppressor sensitive mutant phages M2 and phi 29

Two different expression systems of genes of primer proteins (pE for phage M2, and p3 for phi 29) were constructed to study the protein primed DNA replication of Bacillus phages M2 and phi 29. In one system, expression of the genes was under the control of the inducible spac promoter, whereas in the other system, the expression was under the control of the constitutive promoter in plasmid pUB110. Complementation tests in vivo were performed between the primer proteins expressed by these systems and mutant phages having suppressor sensitive mutations in the genes of the primer proteins. The phages M2 susE and phi 29 sus3 were complemented by pE and p3 expressed by the systems, respectively. However, the complementation and apparent phage DNA synthesis were not detected in the combinations between susE of phage M2 and p3 of phage phi 29, and vice versa. Although pE and p3 proteins exhibited structurally and functionally similar characteristics, these proteins showed species specificity in the protein primed DNA replication of bacteriophages M2 and phi 29.

Ocular circulatory changes following scleral buckling procedures

The effect of segmental scleral buckling (SB) on ocular circulation was evaluated by measurements of the ocular pulse amplitude (PA) and the ophthalmic artery pressure (OAP). In this study the OAP was defined as the intraocular pressure (IOP) at which the PA disappeared during increasing IOP. Twenty four patients with unilateral rhegmatogenous retinal detachment who underwent SB of varying extent were studied; the unoperated fellow eyes served as controls. Both the OAP and the ophthalmic perfusion pressures (OAP minus IOP) decreased significantly (p < 0.01) as the area of SB treatment increased. Follow-up measurements showed that the OAP was relatively lower up to 3 months postoperatively than after 3 months, and then remained stable. Our results indicated that SB affects the ocular pulse measurements and may decrease ocular blood flow because of decreased ophthalmic perfusion pressure, probably due to increased choroidal vascular resistance, and that the greater the extent of the SB treatment, the greater the possibility of decreased ocular blood flow.

The replication origin of proplastid DNA in cultured cells of tobacco

When tobacco suspension culture line BY2 cells in stationary phase are transferred into fresh medium, replication of proplastid DNA proceeds for 24 h in the absence of nuclear DNA replication. Replicative intermediates of the proplastid DNA concentrated by benzoylated, naphthoylated DEAE cellulose chromatography, were radioactively labelled and hybridized to several sets of restriction endonuclease fragments of tobacco chloroplast DNA. The intermediates hybridized preferentially to restriction fragments in the two large inverted repeats. Mapping of D-loops and of restriction fragment lengths by electron microscopy permitted the localization of the replication origin, which was close to the 23S rRNA gene in the inverted repeats. The replication origins in both segments of the inverted repeat in tobacco proplastid DNA were active in vivo.

Receptor sequence in the terminal protein of bacteriophage M2 that interacts with an RGD (Arg-Gly-Asp) sequence of the primer protein

At the initiation of protein-primed DNA replication of bacteriophages M2 and phi 29, the Arg-Gly-Asp (RGD) sequence of primer protein participates in the recognition of terminal protein (TP), where the initiation site for protein-primed DNA replication of template DNA is located. We compared the sequences of M2 and phi 29 TP with those of the members of the integrin superfamily and found the highly homologous sequences Lys-Lys-Ile-Pro-Pro-Asp-Asp (KKIPPDD) in M2 and phi 29 TP and Lys-Lys-Gly-Cys-Pro-Pro-Asp-Asp (KKGCPPDD) in the beta-subunit of fibronectin receptor protein. A synthetic 20mer peptide that contained the KKIPPDD sequence interfered with the inhibitory effect of the RGD peptide on both transfection and the protein-priming reaction in vitro. We propose that the sequence KKIPPDD of M2 TP is the receptor sequence for RGD.

Primer protein of bacteriophage M2 exposes the RGD receptor site upon linking the first deoxynucleotide

Primer protein (PP) of bacteriophages M2 and phi 29 contains an Arg-Gly-Asp (RGD) sequence. The RGD-mediated protein-protein interaction in protein-primed DNA replication of M2 was studied in vitro using three purified and indispensable components: PP, DNA polymerase (POL) and template DNA linked to terminal protein (TP). PP competed with a synthetic RGD peptide for binding to the template DNA-TP complex (TP-DNA). In addition, POL bound to template TP-DNA only when complexed with PP. These results indicate that the RGD sequence of PP is responsible for the interaction of the PP-POL complex with TP-DNA, which contains the initiation site for the protein priming of DNA synthesis. At the moment when PP converts to TP upon linking the first deoxynucleotide, a conformational change results in exposure of the RGD binding site.

A new defective phage containing a randomly selected 8 kilobase-pairs fragment of host chromosomal DNA inducible in a strain of Bacillus natto

A new defective phage, designated PBND8, was induced in Bacillus natto strain IAM1207 with bleomycin and mitomycin C. PBND8 particles contained a randomly selected 8 kilobase-pairs (kbp) fragment of the host chromosomal DNA. Electron microscopy showed that PBND8 has a small head with a complex tail structure like PBSX, a defective phage of Bacillus subtilis 168. The PBND8 head, however, is clearly smaller than that of PBSX which contains 13-kbp fragments of the host chromosomal DNA. SDS-polyacrylamide gel electrophoretic analysis revealed that the structural proteins of PBND8 are distinct from those of PBSX and PBSY (PBSZ) of B. subtilis W23. PBND8 exhibited a bacteriocin-like killing activity to the other Bacillus cells.

Aphidicolin-resistant DNA polymerase of bacteriophage phi 29 APHr71 mutant is hypersensitive to phosphonoacetic acid and butylphenyldeoxyguanosine 5'-triphosphate

Bacteriophage phi 29 DNA polymerase is sensitive to aphidicolin (APH). DNA polymerase of the APH-resistant mutant, APHr71, was more sensitive to phosphonoacetic acid and butylphenyldeoxyguanosine 5'triphosphate than the wild type. Nucleotide sequence analysis revealed a single transition of G at nucleotide 562 to A in the DNA polymerase gene of APHr71, indicating that APHr71 DNA polymerase (572 residues) had a single amino acid substitution from glycine at residue 188 to serine. The results suggest that the site and the neighboring conserved segment of phi 29 DNA polymerase constitute a structure interacting with deoxynucleotides, pyrophosphate, and APH.

[Role of the vitreous in idiopathic preretinal macular fibrosis indicated by visual acuity in follow-up cases]

The vitreous and visual acuity in 103 eyes with idiopathic preretinal macular fibrosis were examined. The vitreous was studied biomicroscopically and the follow-up course was 6 months or more. Twenty-two eyes had no posterior vitreous detachment (group 1), 4 eyes had partial posterior vitreous detachment without traction to the macula (group 2), 17 eyes had partial posterior vitreous detachment with traction to the macula (group 3), and 60 eyes had complete posterior vitreous detachment (group 4). There were significantly more eyes with a visual acuity of 0.4 or worse, decreased acuity, or macular fluorescein leakage in group 3 than in groups 1 or 4. Decreased visual acuity was found in 41% of eyes with macular fluorescein leakage, but in only 11% of eyes without macular fluorescein leakage. It is presumed that the vitreous traction to the macula and macular fluorescein leakage are closely related to the outcome of visual acuity in cases with idiopathic preretinal macular fibrosis.

Primary structure of bacteriophage M2 DNA polymerase: conserved segments within protein-priming DNA polymerases and DNA polymerase I of Escherichia coli

Bacteriophage M2 encodes its own DNA polymerase which catalyses the formation of a primer protein-5'dAMP initiation complex for DNA replication. To understand the relation of structure to function of this 'protein-priming DNA polymerase', we have determined the nucleotide sequence of the M2 DNA polymerase-encoding gene (gene G). The deduced 572-amino acid sequence of M2 DNA polymerase shows 82.3% overall homology to that of phi 29 DNA polymerase. A homology search with the mutation data matrix revealed that six segments (A-F, from the N terminus) of M2 and phi 29 DNA polymerases are homologous with the sequence of Escherichia coli DNA polymerase I (PolI). Segments D and F coincide with the conserved segments of many other DNA polymerases. Therefore, M2 and phi 29 DNA polymerases have structural features, at least in the conserved segments, similar to those of PolI and other DNA polymerases. Based on the homology with PolI and the location of the mutations for aphidicolin resistance and nucleoside analog resistance of M2, phi 29 and herpes simplex virus type-1 DNA polymerases, we propose that segments A-D of the M2 and phi 29 DNA polymerases constitute a structure which forms the cleft for holding template DNA and that segment D is a region for interacting with dNTP.

An inhibitory effect of RGD peptide on protein-priming reaction of bacteriophages phi 29 and M2

The amino acid sequence, arginine-glycine-aspartic acid (RGD), found in some cell adhesive proteins, is a recognition signal for the receptor protein. It is interesting that we have found the RGD sequence in terminal protein (TP) of bacteriophages phi 29 and M2 near an amino acid, the serine residue at 232, covalently linked to the terminal nucleotide of their DNAs. At the initiation of protein-primed DNA replication, TP is essential for the recognition of replication machinery containing DNA polymerase and primer protein (PP; PP becomes TP upon linking the first nucleotide, and hence the primary structure of TP is the same as that of PP). Synthetic peptide RGD specifically inhibited transfection of phi 29 and M2. The target of the RGD peptide is shown to be TP by marker rescue experiments, suggesting that a receptor for the RGD sequence exists in TP. Furthermore, the peptide inhibited the in vitro protein-priming reaction of DNA replication. We propose that the RGD sequence of PP and a putative receptor on TP is utilized for the molecular recognition initiating DNA replication.

Biomicroscopic evaluation and photography of ocular toxoplasmosis

The vitreous of 39 eyes with ocular toxoplasmosis was studied and photographed using an El Bayadi-Kajiura preset lens. In active cases of toxoplasmosis, the vitreous showed inflammatory opacities and gel shrinkage. In inactive cases, the vitreous was often liquefied. Compared with 39 normal eyes of age- and sex-matched controls, the prevalence of partial posterior vitreous detachment was significantly higher in toxoplasmosis (P less than .001). A higher prevalence of posterior vitreous detachment was found in eyes with the major chorioretinal lesion outside the temporal vascular arcade than in those with lesions inside the temporal vascular arcade (P less than .05). Our results indicated that various vitreous changes may cause posterior vitreous detachment and that location of the inflammatory focus may influence the vitreous condition.

[Role of the vitreous in retinal neovascularization evaluated by a comparison of central retinal vein occlusion and branch retinal vein occlusion]

Thirty three patients (33 eyes) with central retinal vein occlusion (CRVO) and 80 patients (81 eyes) with branch retinal vein occlusion (BRVO) were studied in an attempt to investigate the role of the vitreous in the formation of retinal neovascularization. All these eyes had some areas of capillary nonperfusion confirmed by fluorescein angiography and no scatter photocoagulation before the first examination. The incidence of new vessels at the optic disc (NVD) in CRVO was not significantly different from that in BRVO. However, the incidence of new vessels elsewhere (NVE) in CRVO was significantly less than that in BRVO. Follow-up vitreous examination of 36 cases while they had not developed NVD and/or NVE showed a higher incidence of posterior vitreous detachment from the mid-peripheral retina (MP-PVD) in CRVO than in BRVO. On the other hand, there was no statistically significant difference in the incidence of posterior vitreous detachment from the optic disk (D-PVD) between CRVO and BRVO. The high incidence of MP-PVD in CRVO may explain the low incidence of NVE in CRVO.

Tripeptide, Arg-Gly-Asp, inhibits the transfection of protein-linked DNA of bacteriophage M2

The effect of tripeptide, Arg-Gly-Asp (RGD), on the transfection activity of Bacillus phage M2 DNA was examined. The transfection activity decreased when M2 DNA was preincubated with RGD before it was added to competent cells.

Asteroid hyalosis: posterior vitreous detachment and diabetic retinopathy

The vitreoretinal relationship in 59 eyes with asteroid bodies was studied by biomicroscopy with the El Bayadi-Kajiura lens. Complete posterior vitreous detachment (PVD) occurred less often in eyes with asteroid bodies than in control eyes (P less than .05), and partial PVD occurred more often than in control eyes (P less than .01). In eyes with asteroid bodies after the age of 70 years, the prevalence of PVD, either complete or partial, was lower than in age-matched control eyes (P less than .01), and the prevalence of liquefaction (19%) was lower than has been reported in controls. Of eight eyes with proliferative diabetic retinopathy and asteroid bodies, only one showed partial PVD. Patients who were diabetic and who had asteroid bodies were significantly younger than patients without diabetes with asteroid hyalosis (P less than .01). Our data suggest that the presence of asteroid bodies may arrest the process of vitreous collapse or contraction and that diabetes might influence the development of asteroid hyalosis.

Effects of visible-light irradiation on vitreous structure in the presence of a photosensitizer

Sensitized photo-induced changes of vitreous structure were investigated using both in vivo and in vitro model systems. In the former, rabbit eyes were injected with the photosensitizer riboflavin, and in the latter, calf vitreous samples were treated with riboflavin or Methylene Blue prior to irradiation with white light. The active species of oxygen, i.e. singlet oxygen, superoxide anion, hydroxyl radical and hydrogen peroxide, generated by the photodynamic action of the sensitizer, caused significant liquefaction of the calf vitreous in vitro. There was little liquefaction of the rabbit vitreous in vivo, suggesting the presence of a protective mechanism in vivo. hyaluronidase induced significantly greater liquefaction in vitro than either Methylene Blue or riboflavin. This study suggests that loss of gel vitreous structure can result from extensive depolymerization of hyaluronidase by hyaluronidase and less drastic conformation and molecular weight changes in the photosensitized reactions. Although light-induced liquefaction was less marked than enzyme-induced liquefaction, the mechanism of the former is more pertinent to age-related vitreous synchysis.

Aphidicolin-resistant mutants of bacteriophage phi 29: genetic evidence for altered DNA polymerase

Aphidicolin-resistant mutants (Aphr) of Bacillus subtilis bacteriophage phi 29 were isolated after mutagenesis with hydroxylamine. Efficiency of plating (e.o.p.) of the resistant mutants was not reduced at 500 microM aphidicolin, although e.o.p. of wild type phi 29 was less than 10(-5) at the same concentration of aphidicolin. By recombination and complementation analyses, both sites of the mutations, aph-71 and aph-101, of Aphr71 and Aphr101, respectively, were mapped in gene 2 which encodes phi 29 DNA polymerase. The activity of wild type phi 29 DNA polymerase, in a partially purified fraction, was inhibited by aphidicolin. DNA polymerases from Aphr71 and Aphr101, prepared in the same manner as that of wild type, were resistant to the drug. These results indicate that the acquisition of the aphidicolin resistance of Aphr71 and Aphr101 of bacteriophage phi 29 results from a structural alteration of phi 29 DNA polymerase which reduces sensitivity to aphidicolin.

The nucleotide sequences of the heterologous region between the genomes of Bacillus phages M2 and Nf that indicate the two phages are originally identical

It has been suggested that the heterologous population of Bacillus phage M2 is derived from an original clone, which is identical with phage Nf, by the deletion on a particular region of the genome. We have determined the nucleotide sequence of this region of M2 subclones and Nf genomes. The results clearly indicate that the homologous recombination through the short direct repeated sequence is the main cause of the varied deletions found in the genomes of M2 subclones.

Role of the vitreous in idiopathic preretinal macular fibrosis

Of 250 eyes with idiopathic preretinal macular fibrosis, 56 had no posterior vitreous detachment (Group 1), ten had partial posterior vitreous detachments without vitreous traction to the macula (Group 2), 29 had partial posterior vitreous detachments with vitreous traction to the macula (Group 3), and 155 had complete posterior vitreous detachments (Group 4). There were significantly more eyes with visual acuities of 20/60 or worse, cystoid macular changes, or macular fluorescein leakage in Group 3 than in Group 1 or Group 4. Thus, the presence of vitreous traction to the macula was associated with worse anatomic and functional findings.

Nucleotide sequence of gene F of Bacillus phage Nf

The nucleotide sequence of Bacillus phage Nf gene F has been determined. The deduced amino acid sequence of gpF is very similar to that of gp4, the transcriptional activator of phage phi 29. Both proteins contain the consensus structure that is conserved for the DNA-protein interacting domain of DNA-binding proteins such as the repressor, Cro and CII proteins of phage lambda.

Examination of the vitreous. A comparison of biomicroscopy using the Goldmann and El Bayadi-Kajiura lenses

Vitreous examinations using the three-mirror Goldmann and the preset El Bayadi-Kajiura lenses were performed on 222 eyes. The presence of posterior vitreous detachment, vitreous traction, liquefaction, lacunae, and cells was noted. Clinical findings using the two lenses differed in 10% of the variables studied. The accuracy of the El Bayadi-Kajiura technique was confirmed by clinical and histological examination of 20 animal eyes with experimentally altered vitreous. The Goldmann lens afforded examination of peripheral vitreous and better identification of cells in the vitreous, whereas the El Bayadi-Kajiura lens permitted better visualization of complex vitreoretinal relationships.

Vitreous changes in peripheral uveitis

The vitreous in 76 eyes with peripheral uveitis was examined and compared with the vitreous in 77 eyes of age- and sex-matched controls. The vitreous findings in peripheral uveitis were inflammatory and cotton ball-like opacities, gel shrinkage, and posterior vitreous detachment. The prevalence of partial and complete vitreous detachment was significantly higher in the peripheral uveitis group than in the control group. The prevalence of partial vitreous detachment was significantly higher in eyes with macular change than in eyes without macular change, whereas the prevalence of complete vitreous detachment was significantly higher in eyes without macular change than in eyes with macular change. We also found a significantly higher prevalence of complete vitreous detachment in eyes with visual acuity of 20/50 or better than in those with an acuity of 20/60 or worse. The prevalence of partial vitreous detachment was significantly higher in eyes with a visual acuity of 20/60 or worse than in those with an acuity of 20/50 or better.