Riva Rubinstein

The nucleic acids of viruses infecting Heliothis armigera

Abstract The nucleic acids of three viruses infecting Heliothis armigera have been studied. A nuclear polyhedrosis virus and granulosis virus contained double-stranded DNA. A cytoplasmic polyhedrosis virus contained double-stranded RNA, and polyacrylamide gel electrophoresis showed that the genome consisted of 10 discrete double-stranded RNA components.

BK virus DNA cloned directly from human urine confirms an archetypal structure for the transcriptional control region

A BK virus isolate cloned from the urine of an immunosuppressed patient was identified as the WW strain. Fine mapping using four base-pair restriction enzymes identified a number of small deletions and insertions relative to prototype BK. The finding of a transcriptional control region with a structure similar to that of a previous isolate cloned in a similar way demonstrates that this is a reproducible finding and reinforces the hypothesis that the structure is the archetypal form, found when cloned directly from urine, but generally altered when passaged in cell culture.

Midgut and Viral Associated Proteases of Heliothis armigera

The role played by the gut juice of insects in the infective process of insect viruses was examined. Analysis of larval gut extract of Heliothis armigera by SDS-PAGE revealed protease activity associated with components of molecular weights 48,000 and 94,000. Proteases were found to be associated with occlusion bodies and virions of both nuclear polyhedrosis virus (NPV) and cytoplasmic polyhedrosis virus (CPV) infecting H. armigera. CPV occlusion bodies were dissolved by gut juice extract at pH 8.0, trypsin and chymotrypsin at pH 8.0, and carbonate-chloride solution at pH 10.5. Trypsin treatment was selective for occlusion bodies of CPV at pH 8.0, whereas solutions more alkaline than pH 10.0 without added enzymes were adequate to digest NPV occlusion bodies. This property was used to identify and separate the two types of viruses from a mixed infection. Gut extract proteases have characteristics similar to those of trypsin.

Reproducible alteration of cytoplasmic polyhedrosis virus double-stranded RNA genome patterns on laboratory passage

Abstract A change in the polyacrylamide gel electrophoretic pattern of the double-stranded RNA genome segments of a cytoplasmic polyhedrosis virus was observed following only one or two passages through laboratory-reared larvae of Heliothis armigera . This change consisted of the loss of a high molecular weight segment concomitant with the appearance of a low molecular weight segment and was a reproducible feature observed with several separate isolates from the field.

Molecular weights of the RNA genome segments of a cytoplasmic polyhedrosis virus determined by a new comparative approach

Abstract A cytoplasmic polyhedrosis virus (CPV) from Heliothis armigera contains 10 double-stranded RNA genome segments which are all well resolved on polyacrylamide gel electrophoresis. The relationship between log molecular weight and electrophoretic mobility in polyacrylamide gels has been studied using 32 P-labeled CPV RNA, and has been shown to deviate markedly from linearity at the higher molecular weight values. A new relationship between molecular weight and electrophoretic mobility for doubles-tranded RNA has therefore been defined and used to determine the absolute molecular weight of the CPV RNA by comparison with reovirus type 3 RNA.

The multicomponent genome of a different cytoplasmic polyhedrosis virus isolated from Heliothis armigera.

The genome of a new cytoplasmic polyhedrosis virus (CPV) isolated from Heliothis armigera has been shown to consist of 10 double-stranded RNA segments, as in other CPVs, but the genome profile on PAGE bears no resemblance to previously described CPVs isolated from H.armigera.

Some Physical Characteristics of a Cytoplasmic Polyhedrosis Virus of Heliothis armigera

A number of physical properties of a cytoplasmic polyhedrosis virus of Heliothis armigera were determined. These included a buoyant density of 1.44 g/cm3, a diffusion coefficient of 0.73 x 10(-7) cm2/sec, a partial specific volume of 0.688 ml/g, and a sedimentation coefficient of 399S. Three different methods were used to determine an average molecular weight of 47.4 x 10(6).

Prevalence of Factor V Leiden in three ethnic groups of patients with deep vein thrombosis in the Western Cape province of South Africa.

To the Editor: Venous thromboembolism in the Western world is associated both with acquired risk and genetic factors (1), notably activated protein C (APC) resistance (2). This is inherited as an autosomal dominant trait that is present in 20±60% of patients with thrombophilia (3). Factor V Leiden (FV Leiden), the R506Q mutation in the factor V gene, is found in 90±95% of APC resistance cases. The mutation results in a product that is degraded more slowly by APC (4). Heterozygotes have a seven-fold and homozygotes an eighty-fold increased risk of venous thrombosis (5). De®ciency of protein C or protein S, hyperhomocysteinaemia, polymorphisms in the prothrombin gene (6) or acquired risk factors, such as oral contraceptives or pregnancy (7, 8), are associated with an increased risk of venous thrombosis (VT) in APC-resistant patients. The prevalence of FV Leiden in populations of North European origin is 3.5±8% (1), whereas this mutation is absent in African and Asian populations (9). We report on the prevalence of FV Leiden among individuals with VT in the three ethnic groups of the Western Cape of Southern Africa. We investigated 111 consecutive patients who presented with deep vein thrombosis. Suspected VT was con®rmed with contrast venography or Doppler ultrasound studies. Patients were matched for age, gender and ethnic group, with 103 patients having various medical conditions but no clinical evidence of thrombosis. Patients and control subjects were separated into three race groups, (i) Caucasian, (ii) Mixed Ancestry (who possess Western European, indigenous Southern African and Southeast Asian genes) (10), and (iii) South African Black (Table 1). Our patient sample conformed to the general admission pattern: 11% were Caucasian, 62% of Mixed Ancestry, and 28% Black African. Genomic DNA was screened by PCR ampli®cation of exon 10 of the FV gene, followed by digestion with Mnl I (New England Biolabs, Beverly, MA, USA) to detect the presence of 506 Arg to Gln in the factor V gene (2). The x and Fishers exact tests were employed to determine differences in frequency of risk factors, and of FV Leiden. Odds ratios were determined for thrombosis risk and adjusted for age, sex, and race in logistic regression analysis. The Mann±Whitney U-test was used to compare ages of the different study groups. A summary of the results is shown in Table 1. The FV Leiden mutation was found in only one of the 24 Caucasians and in none of the other 79 control subjects. Patients ranged in age from 1 to 76 yr (median age 36); the presentation age in Black Africans was signi®cantly lower (30 years; p=0.0009) than in the groups of Mixed Ancestry (37 yr) or Caucasians (44 yr). The frequency of FV Leiden in patients with VT was highest ( 26%) in the Caucasian group, 8% in the Mixed Ancestry group, and none in the Black African patients (p=0.01 and 0.007). In our study there was a higher proportion of female patients with DVT (70%). Although three of 36 males with VT were heterozygous for FV Leiden, its prevalence was the same in both genders (p=0.5). Ridker et al. (11) found a low prevalence of FV Leiden in Americans of African, Hispanic, Asian and native Indian origin, but this may represent the effects of undetermined ethnic mixing similar to that of our Mixed Ancestry group (1). However, our patients of Black African descent were mainly rural in origin, with minimal intermarriage. We were unable to detect the mutation in indigenous Black Africans either in the control or in the patient group, con®rming the ®ndings by Rees et al. (9), Pepe et al. (12), and Hooper et al. (13) whose studies, however, did not include the Black and non-Negroid population groups of Southern Africa. The higher incidence in the Caucasian group is similar to ®ndings in studies on North European patients. The intermediate proportion in the Mixed Ancestry group may represent a founder effect from the early North European Caucasian early settlers. Eur J Haematol 2000: 65: 78±79 Printed in UK. All rights reserved Copyright # Munksgaard 2000