Demarcation of Viral Shelters Results in Destruction by Membranolytic GTPases: Antiviral Function of Autophagy Proteins and Interferon‐Inducible GTPases

A hallmark of positive‐sense RNA viruses is the formation of membranous shelters for safe replication in the cytoplasm. Once considered invisible to the immune system, these viral shelters are now found to be antagonized through the cooperation of autophagy proteins and anti‐microbial GTPases. This coordinated effort of autophagy proteins guiding GTPases functions against not only the shelters of viruses but also cytoplasmic vacuoles containing bacteria or protozoa, suggesting a broad immune‐defense mechanism against disparate vacuolar pathogens. Fundamental questions regarding this process remain: how the host recognizes these membranous structures as a target, how the autophagy proteins bring the GTPases to the shelters, and how the recruited GTPases disrupt these shelters. In this review, these questions are discussed, the answers to which will significantly advance our understanding of the response to vacuole‐like structures of pathogens, thereby paving the way for the development of broadly effective anti‐microbial strategies for public health.     

In situ characterization of beta-amyloid in Alzheimer''s diseased tissue by synchrotron Fourier transform infrared microspectroscopy.

We report the first evidence of the structure of beta-amyloid protein as it exists in situ within a slice of human Alzheimer's diseased brain tissue. Using a Fourier transform infrared microspectroscopic technique, areas of interest can be selected for spectral measurements with regions of potential contamination masked. In so doing, it is possible to obtain infrared spectra only of beta-amyloid and not the surrounding grey matter within which it lies. However, to obtain spectra of high-quality signal-to-noise ratio using a conventional infrared source, we were limited to aperture sizes between 24 microns x 24 microns to 50 microns x 50 microns. Markedly improved high-quality spectra were acquired with infrared radiation provided by a synchrotron light source (National Synchrotron Light Source, Brookhaven National Laboratories), using aperture sizes as small as 12 microns x 12 microns. This allowed spectroscopic mapping of brain tissue regions containing amyloid. We observe that in situ protein of grey matter exist predominantly in an alpha-helical and/or unordered conformation, whereas within amyloid deposits a beta-sheet structure predominates. The hydrogen bonding strength of the beta-structure found in situ is different from that reported in the literature for isolated/chemically synthesized beta-amyloid peptides.     

Increasing incidence of tuberculosis in England and Wales: a study of the likely causes.

OBJECTIVE--To examine factors responsible for the recent increase in tuberculosis in England and Wales. DESIGN--Study of the incidence of tuberculosis (a) in the 403 local authority districts in England and Wales, ranked according to Jarman score, and (b) in one deprived inner city district, according to ethnic origin and other factors. SETTING--(a) England and Wales 1980-92, and (b) the London borough of Hackney 1986-93. MAIN OUTCOME MEASURE--Age and sex adjusted rate of tuberculosis. RESULTS--In England and Wales notifications of tuberculosis increased by 12% between 1988 and 1992. The increase was 35% in the poorest 10th of the population and 13% in the next two; and in the remaining 70% there was no increase. In Hackney the increase affected traditionally high risk and low risk ethnic groups to a similar extent. In the "low risk" white and West Indian communities the incidence increased by 58% from 1986-8 (78 cases) to 1991-3 (123), whereas in residents of Indian subcontinent origin the increase was 41% (from 51 cases to 72). Tuberculosis in recently arrived immigrants--refugees (11% of the Hackney population) and Africans (6%)--accounted for less than half of the overall increase, and the proportion of such residents was much higher than in most socioeconomically deprived districts. The local increase was not due to an increase in the proportion of cases notified, to HIV infection, nor to an increase in homeless people. CONCLUSIONS--The national rise in tuberculosis affects only the poorest areas. Within one such area all residents (white and established ethnic minorities) were affected to a similar extent. The evidence indicates a major role for socioeconomic factors in the increase in tuberculosis and only a minor role for recent immigration from endemic areas.     

A region of primer binding variation at the D6S265 locus associated with HLA-A25 and HLA-A26 antigens

D6S265 is a polymorphic dinucleotide repeat, mapped within 70 kb centromeric of HLA-A, on chromosome 6p21.3. While genotyping families for genetic linkage analysis, allele non-amplification resulting in apparent non-Mendelian inheritance was observed at the D6S265 locus in 15 individuals, on chromosomes carrying the HLA-A25 and HLA-A26 antigens. The D6S265 locus was sequenced in a variant individual homozygous for allele non-amplification, and in a non-HLA-A25/-A26 individual, homozygous for D6S265 allele 1. Five base changes were identified in the reverse primer binding region of the variant individual, effectively preventing annealing of the 3 primer to the template.     

Genetic analysis of mutagenesis in aging Escherichia coli colonies

Bacteria live in unstructured and structured environments, experiencing feast and famine lifestyles. Bacterial colonies can be viewed as model structured environments. SOS induction and mutagenesis have been observed in aging Escherichia coli colonies, in the absence of exogenous sources of DNA damage. This cAMP-dependent mutagenesis occurring in Resting Organisms in a Structured Environment (ROSE) is unaffected by a umuC mutation and therefore differs from both targeted UV mutagenesis and recA730 (SOS constitutive) untargeted mutagenesis. As a recB mutation has only a minor effect on ROSE mutagenesis it also differs from both adaptive reversion of the lacI33 allele and from iSDR (inducible Stable DNA Replication) mutagenesis. Besides its recA and lexA dependence, ROSE mutagenesis is also uvrB and polA dependent. These genetic requirements are reminiscent of the untargeted mutagenesis in λ phage observed when unirradiated λ infects UV-irradiated E. coli. These mutations, which are not observed in aging liquid cultures, accumulate linearly with the age of the colonies. ROSE mutagenesis might offer a good model for bacterial mutagenesis in structured environments such as biofilms and for mutagenesis of quiescent eukaryotic cells. Received: 30 April 1997 / Accepted: 1 July 1997     

Expression of heterologous phytochromes A, B or C in transgenic tobacco plants alters vegetative development and flowering time

In this study, oat phytochrome A (phyA), Arabidopsis phytochrome B (phyB) or Arabidopsis phytochrome C (phyC) were expressed in both day-neutral and photo-period-sensitive (short-day) tobacco (Nicotiana tabacum cv. Hicks). Introgression of the Maryland Mammoth (MM) gene into cv Hicks was used to confer short-day photo-periodic sensitivity. Expression of oat phyA led to characteristic hypersensitivity of hypocotyls to red light (R) and far-red light (FR) and an overall dwarfing of the mature plant. Expression of Arabidopsis phyB enhanced the sensitivity of hypocotyls to R and caused even more marked dwarfing of the mature plant. In contrast, the expression of Arabidopsis phyC had no detectable consequences for the photocontrol of hypocotyl elongation. However, phyC expression did lead to a R-dependent increase in cotyledon expansion in de-etiolating seedlings and to a significant increase in leaf area in mature plants. This provides the first experimental evidence that phyC is biologically active. The flowering time of cv Hicks plants grown under 8 h photoperiods was virtually unaffected by a 30 min white light (W) night break given 8 h into the dark period. In contrast, cv Hicks MM plants responded to a night break with a delay in flowering. Expression of phyA or phyB led to a night break-dependent delay in flowering in cv Hicks plants. For cv Hicks MM plants, the expression of any of phyA, phyB or phyC caused a marked enhancement of the flower-delaying effect of a night break. These observations indicate that transgenic phyA, phyB or phyC can interact with the endogenous mechanisms controlling flowering time in tobacco.     

Suitability of oven-dried root nodules for Rhizobium strain identification by immunofluorescence and agglutination

Legume root-nodules, dried at oven temperature (70°C for 48 h) were suitable for Rhizobium strain identification by immunofluorescence and agglutination. The fluorescence of bacteroids of R. japonicum, R. leguminosarum, R. meliloti, R. phaseoli , and Rhizobium spp. from oven-dried nodules was the same as those from frozen, desiccated, or nodules dried at room temperature (28°C). Oven-dried nodules did not require further steaming for agglutination. Bacteroid agglutinations gave 2–16 fold lower titres than those of the cultured cells. Fresh and oven-dried soybean rhizobia from a mixed inoculation gave exactly the same results when identified by immunofluorescence or agglutination.     

Transactions of the One Hundredth Annual Meeting of The Canadian Medical Association: Part II

The purpose of this retrospective study was to compare (1) regular methadone withdrawal treatment and (2) prolonged methadone withdrawal treatment in 105 and 71 voluntary patients respectively, who attended the Narcotic Addiction Foundation (N.A.F.) between 1959 and mid-1964. Treatment consisted of individual counselling and medical care for all, and only residential care and psychiatric assessment for selected cases. The number of treatment sessions and the details of drug therapy are described.One hundred and fifty-three of 176 patients (87%) were interviewed approximately one to five years after the first clinic contact. Forty-three per cent showed some overall improvement in their behaviour. Rehabilitation was defined as change in a specific area—drug use, work, criminal behaviour, community associations, friendship patterns and family relationships—rather than in terms of abstention from drugs only. Age affected comparative results.     

Specificity of recA441-mediated (tif-1) mutational events.

Summary To investigate the impact of SOS induction on the distribution of spontaneous mutation, 111 recA441-mediated mutations were characterized at the DNA sequence level in the lacI gene of Escherichia coli. A 2.6-fold enhancement in lacI ^– mutation frequency was observed after induction of the SOS system in the absence of mutagenic treatment, and specific classes of mutational events were induced. G : C C : G, G : C T : A and A : T T : A transversion events were specifically enhanced after SOS induction. A preferential 5-Y-Purine-3 neighbouring base specificity for these transversion events is reported here (normalised for mutation of the purine residue). In addition, a preference for transversion events at 5-C/GTGG-3 sequences is also observed. Fifty events were recovered at the lacI frameshift hotspot site and were equally represented by 4 bp addition and deletion events. This 1:1 ratio deviates significantly from the 4:1 distribution characteristic of spontaneous frameshift mutation in the RecA⁺ background and is a consequence of the fourfold induction of the (–)4 event. This abberrant distribution was confirmed by oligomeric probing of 474 independent recA441-mediated spontaneous lacI ^– mutations.     

Mites of the familyMacrochelidae as predators of two species of dung-breeding pest flies

Nine species of macrochelid mites [Macrocheles “glaber” (Müller),M. aestivus Halliday,M. mammifer Berlese,M. peniculatus Berlese,M. robustulus (Berlese),M. merdarius (Berlese),M. peregrinus Krantz,M. eurygaster Krantz,Glyptholaspis confusa (Foà) were tested in the laboratory as predators of 2 species of dung-breeding pest flies (Musca vetustissima Walker,Haematobia irritans exigua de Meijere). The mites varied in their ability to attack the 2 fly species at both egg and larval stages. larger mites were generally more effective predators than the smaller species. The level of predation imposed byM. “glaber” onMusca vetustissima also varied with the developmental stage of both predator and prey.