Low-level inversion of the L component of pseudorabies virus is not dependent on sequence homology.

Pseudorabies virus has a class 2 genome in which the S component is found in two orientations relative to the L component. The L component is bracketed by sequences that are partially homologous; it is found mainly in one orientation, but a small proportion is inverted (J. M. DeMarchi, Z. Lu, G. Rall, S. Kuperschmidt, and T. Ben-Porat, J. Virol. 64:4968-4977, 1990). We have ascertained the role of the patchy homologous sequences bracketing the L component in its inversion. A viral mutant, vYa, from which the sequences at the right end of the L component were deleted was constructed. Despite the absence of homologous sequences bracketing the L component in vYa, its L component inverted to an extent similar to that of the L component in the wild-type virus. These results show the following. (i) The low-frequency inversion of the L component of PrV is not mediated by homologous sequences bracketing this component. (ii) Cleavage of concatemeric DNA at the internal junction between the S and L components is responsible for the appearance of the minority of genomes with an inverted L component in populations of pseudorabies virus. (iii) The signals present near or at the end of the S component are sufficient to allow low-frequency cleavage of concatemeric DNA; the sequences at the end of the L component are not essential for cleavage, although they enhance it considerably.     

A preliminary report on a bacteriological assay for compound 1080 (sodium monofluoroacetate)

A new, inexpensive, simple and rapid bioassay for sodium monofluoroacetate (compound 1080) was developed using bacteria. Two 1080-sensitive isolates ( Bacillus sp. DHW and Acinetobacter sp. DHW) from local aquatic environments were tested on different agar media using the disc diffusion technique. Both bacteria exhibited zones of growth inhibition surrounding the 1080 discs that were linearly proportional to the concentrations (log₁₀) of 1080. Preliminary studies indicate that this technique can be used for assaying 1080 in environmental and biological samples.     

Localization of blood coagulation factors and fibrinolysis factors within lymphoid germinal centers in human lymph nodes.

The presence of nineteen blood coagulation factors and fibrinolysis factors was immunohistochemically evaluated in human lymph node germinal centers (GCs). Twelve of these factors were detected within lymphoid GCs. The predominant pattern was dendritic with occasional crescent-shaped, ring-shaped or 'moth-eaten' appearance. Immunostains of factor VIII-related antigen, factor I, protein C, tetranectin, antithrombin III, type 2-plasminogen activator inhibitor, and alpha 2-plasmin inhibitor were almost entirely absent from GCs, although they reacted in vascular wall and lumen, respectively. The immunostaining to high molecular weight kininogen, kallikrein, factors XII, X, V, II, XIIIa, XIIIs, plasminogen, tissue-plasminogen activator, and type 1-plasminogen activator inhibitor more frequently revealed a positive dendritic pattern. Immuno-electron microscopy demonstrated factor X and factor XIIIa attached to the cell surfaces of lymphocytes, macrophages, and follicular dendritic cells (FDCs); and in the intercellular space within GCs, especially attached to the labyrinthine-like structure of FDCs. No reaction products were observed in the perinuclear cisternae and rough endoplasmic reticulum in either lymphocytes or FDCs. Our data demonstrate that human lymphoid GCs really contain some of the proteins related to the blood coagulation and fibrinolysis cascades.     

Root growth inhibition of the holorganic layer of moder humus under spruce (Picae abies KARST.) and beech (Fagus Silvatica L.)

A test of root growth inhibition of spruce and beech roots, according to Lynch's procedure (1977), shows the inhibitory effects of soil solution extracted from the holorganic layers (Of₂-Oh) under beech and spruce. Molecular gel filtration of soil solutions shows that the molecular weights vary over a wide range, from less than 100 to over 40,000 daltons. Chemical analysis, using CGC, HPLC and sometimes MS shows only negligible concentrations of simple aliphatic (C₁-C₅) and aromatic acids in the free state. Using the fraction scheme of Forsyth (1977) and the carbazole procedure, it is shown that uronic acids represent only a small percentage of the carboxylic acids, and have no inhibitory effects on root growth. By analogy with results of other authors, the presence of polycarboxylic acids in the soil solution are considered to be the main cause of root growth inhibition.     

Diagnosis of urogenital Chlamydia trachomatis infection in women based on mailed samples obtained at home: multipractice comparative study.

OBJECTIVE: To compare urine and vaginal flush samples collected by women at home with endocervical and urethral swabs obtained by general practitioners for their efficacy in the diagnosis of urogenital Chlamydia trachomatis infection. DESIGN: Multipractice comparative study. SETTING: 33 general practices and a central department of clinical microbiology in Aarhus County, Denmark. SUBJECTS: 222 women aged 18-25 years who for any reason had a gynaecological examination. INTERVENTIONS: Endocervical and urethral swabs were obtained by the women''s general practitioners. The same women when at home then collected a first void urine sample, a midstream urine sample, and a vaginal flush sample (using a vaginal pipette) and mailed them to the laboratory. MAIN OUTCOME MEASURES: C trachomatis defected by the polymerase chain reaction and the ligase chain reaction. Eight tests for C trachomatis were performed for every woman. When two of the eight yielded positive results the patient was considered infected. RESULTS: The overall prevalence of C trachomatis infection was 11.2% (23/205 women). Test sensitivities in samples obtained by general practitioners, samples obtained at home subjected to polymerase chain reaction, and samples obtained at home subjected to ligase chain reaction were 91%, 96%, and 100% respectively. The corresponding specificities were 100%, 92.9%, and 99.5%. CONCLUSIONS: The diagnostic efficacy of samples obtained by women at home and mailed to the laboratory was as good as for samples obtained by a general practitioner when using the ligase chain reaction. This may have important implications for the practicability of screening for this common, often asymptomatic, and treatable infection.     

Past,present and future utilisation ofMyrica gale (Myricaceae)

The development ofM. gale oil as an insect repellent has created a requirement for cultivation of the plant. Botanical evidence indicates thatM. gale is likely to thrive on well—aerated acid peatland and could become a valuable crop on land of low agricultural value. Plant growth would be enhanced by the prevention of grazing and could be combined with softwood forestry since the trees would benefit from soil nitrogen enrichment thanks to the symbiotic association ofM. gale andFrankia. The economics of oil production would be improved if additional compounds of value such as pharmacologically active fiavonoids could be extracted from the by-products.