Complementation and regulatory interaction between two cloned fimbrial gene clusters of Escherichia coli strain KS71

Summary Complementation experiments with cloned DNA fragments encoding either the KS71A, the KS71B or the KS71C fimbriae of the pyelonephritogenic Escherichia coli strain KS71 were used to localise the P-fimbrillin genes and to demonstrate regulatory interactions between the cloned genes. The structural genes of the KS71A and KS71B fimbriae were located within a common 1.1 kilobase pair ClaI-SmaI fragment, and it was shown that the gene clusters for these fimbriae could complement each other in trans. The gene cluster encoding the KS71C fimbriae did not complement for the other KS71 fimbriae. A DNA fragment, located near the KS71A fimbrillin gene, was found to enhance the production of the KS71B fimbriae in trans.     

Combined interferon and vinblastine treatment of advanced melanoma: evaluation of the treatment results and the effects of the treatment on immunological functions

Summary Thirteen patients with metastatic malignant melanoma received interferon -2a (Roferon-A) and vinblastine. The interferon dosage was increased from 3×10⁶ IU to 9×10⁶ IU daily in 10 weeks and thereafter 9×10⁶ IU was administered three times weekly intrasmuscularly. Vinblastine (0.075–0.15 mg/kg) was given every third week intravenously. One of the ten evaluable patients had partial remission (PR) (11%) for 10 months. The diseases was stabilized (NC) in three patients (30%) for 3, 6 and 9 months. Progression (PD) occurred in six patients. The treatment time varied from 5 weeks to 44 weeks. The median survial time from the beginning of this combination treatment was 5 months. The most common side-effects were fever, fatigue, loss of taste, weight loss and neutropenia.The mitogen response to phytohemagglutinin and purified protein derivative of tuberculin decreased in all patients. The response to concanavalin A decreased less and began to increase again in the patients with PR and NC. The natural killer cell activity in PD patients decreased more than in the patients with PR and NC. The ratio of T4/T8-positive cells was restored in PR + NC patients but rose in PD patients indicating a difference in the immunomodulatory effect of the combination or of the advanced disease itself on T-cell function in PD patients.This combination of daily interferon and vinblastine did not prove to be effective in melanoma. The depression of immunological functions, which was more marked in patients with PD, might indicate that vinblastine in this combination counteracts the immunostimulatory effect of interferon.     

Mitochondrial DNA and Y-chromosomal diversity in ancient populations of domestic sheep (Ovis aries) in Finland: comparison with contemporary sheep breeds

Background

Several molecular and population genetic studies have focused on the native sheep breeds of Finland. In this work, we investigated their ancestral sheep populations from Iron Age, Medieval and Post-Medieval periods by sequencing a partial mitochondrial DNA D-loop and the 5’-promoter region of the SRY gene. We compared the maternal (mitochondrial DNA haplotypes) and paternal (SNP oY1) genetic diversity of ancient sheep in Finland with modern domestic sheep populations in Europe and Asia to study temporal changes in genetic variation and affinities between ancient and modern populations.

Results

A 523-bp mitochondrial DNA sequence was successfully amplified for 26 of 36 sheep ancient samples i.e. five, seven and 14 samples representative of Iron Age, Medieval and Post-Medieval sheep, respectively. Genetic diversity was analyzed within the cohorts. This ancient dataset was compared with present-day data consisting of 94 animals from 10 contemporary European breeds and with GenBank DNA sequence data to carry out a haplotype sharing analysis. Among the 18 ancient mitochondrial DNA haplotypes identified, 14 were present in the modern breeds. Ancient haplotypes were assigned to the highly divergent ovine haplogroups A and B, haplogroup B being the major lineage within the cohorts. Only two haplotypes were detected in the Iron Age samples, while the genetic diversity of the Medieval and Post-Medieval cohorts was higher. For three of the ancient DNA samples, Y-chromosome SRY gene sequences were amplified indicating that they originated from rams. The SRY gene of these three ancient ram samples contained SNP G-oY1, which is frequent in modern north-European sheep breeds.

Conclusions

Our study did not reveal any sign of major population replacement of native sheep in Finland since the Iron Age. Variations in the availability of archaeological remains may explain differences in genetic diversity estimates and patterns within the cohorts rather than demographic events that occurred in the past. Our ancient DNA results fit well with the genetic context of domestic sheep as determined by analyses of modern north-European sheep breeds.     

Detection of bacterial contamination in starch and resin-based papermaking chemicals using fluorescence techniques

Rapid fluorescence techniques were evaluated for the detection of bacterial contaminants in papermaking chemicals including starch and the resin-based sizes and starch slurries used in the paper industry. Viable and non-viable bacterial cells were visualised by fluorescent probes and detected by epifluorescence microscopy and flow cytometry. The best discrimination ability was obtained with the fluorescent probes LIVE/DEAD and SYBR Green, based on the staining of cellular nucleic acid, and ChemChrome V3, which demonstrated cellular enzymatic activity. The process samples had to be diluted and filtered before fluorescence staining and analysis because they were viscous and contained solid particles. Fluorescence microscopic counts of bacteria in highly contaminated process samples were similar to plate counts, but flow cytometric enumeration of bacterial cells in process samples yielded 2- to 10-fold lower counts compared with plate counts, depending on the consistency of the sample. The detection limits in flow cytometric analysis and in epifluorescence microscopy were 10³–10⁶ cells ml⁻¹ and 10⁵–10⁶ cells ml⁻¹, respectively. Intrinsic bacterial contamination was detectable with fluorescence techniques and highly contaminated process samples could be analysed with fluorescence methods. Electronic Publication     

Synthetic prions with novel strain-specified properties

Prions are infectious proteins that possess multiple self-propagating structures. The information for strains and structural specific barriers appears to be contained exclusively in the folding of the pathological isoform, PrP^Sc. Many recent studies determined that de novo prion strains could be generated in vitro from the structural conversion of recombinant (rec) prion protein (PrP) into amyloidal structures. Our aim was to elucidate the conformational diversity of pathological recPrP amyloids and their biological activities, as well as to gain novel insights in characterizing molecular events involved in mammalian prion conversion and propagation. To this end we generated infectious materials that possess different conformational structures. Our methodology for the prion conversion of recPrP required only purified rec full-length mouse (Mo) PrP and common chemicals. Neither infected brain extracts nor amplified PrP^Sc were used. Following two different in vitro protocols recMoPrP converted to amyloid fibrils without any seeding factor. Mouse hypothalamic GT1 and neuroblastoma N2a cell lines were infected with these amyloid preparations as fast screening methodology to characterize the infectious materials. Remarkably, a large number of amyloid preparations were able to induce the conformational change of endogenous PrP^C to harbor several distinctive proteinase-resistant PrP forms. One such preparation was characterized in vivo habouring a synthetic prion with novel strain specified neuropathological and biochemical properties.     

Pollen allergen reports help to understand preseason symptoms

Early symptoms of pollen allergies arefrequently reported before pollination periodof allergenic plant starts. At northernlatitudes the main concern is Betulaceae-trees(alders, hazel, birches). Pollen allergeninformation, based on the analysis of actualairborne allergen concentrations, beside thetraditional pollen reports, based on pollencounts, has been given in SW Finland since1998. 1–2 weeks before the onset of floweringpollen allergens are detected airborne inquantities high enough to provoke symptoms.Information is given on radio and in localnewspapers. During the first season of the newservice (1998) we carried out a questionnairestudy. The results showed that new informationservice, though not as frequently used as wehad hoped for, was useful to allergic personsfor starting their medication in time. Theyalso received explanation for their earlierinexplicable symptoms. We recommend bothinformation services to be run concurrently togive the best information to the public.     

Influence of the North Atlantic Oscillation on grass pollen counts in Europe

Relationships between temporal variations in the North Atlantic Oscillation (NAO) and grass pollen counts at 13 sites in Europe, ranging from Córdoba in the south-west and Turku in the north-east, were studied in order to determine spatial differences in the amount of influence exerted by the NAO on the timing and magnitude of grass pollen seasons. There were a number of significant (P < 0.05) relationships between the NAO and start dates of the grass pollen season at the 13 pollen-monitoring sites. The strongest associations were generally recorded near to the Atlantic coast. Several significant correlations also existed between winter averages of the NAO and grass pollen season severity. Traditional methods for predicting the start or magnitude of grass pollen seasons have centred on the use of local meteorological observations, but this study has shown the importance of considering large-scale patterns of climate variability like the NAO.     

Kinetics of phase variation between S and type-1 fimbriae of Escherichia coli

Abstract The rate of fimbrial phase variation in Escherichia coli strain 3040 was determined. The strain has type-1 and S fimbriae. The bacterial culture was fractionated into homogeneous subpopulations expressing either one of the fimbrial types only; the subpopulations were inoculated into broth and the fimbriation of individual cells was assayed by immunofluorescence as a function of time. The rate of the shift from S- or type-1-fimbriate cells to non-fimbriate ones was of the order of 10⁻² per cell generation and more rapid than a direct shift from one fimbrial phase to another, although both types of phase variations were observed.     

Fractionation of a bacterial cell population by adsorption to erythrocytes and yeast cells

Abstract Fluorochrome-labeled antibodies specific for either S or type-1 fimbriae of Escherichia coli were used to show that in broth culture the two fimbrial types of strain 3040 mostly occurred on different cells. 12% of the cells were nonfimbriated. A fractionation procedure that involved adsorption of bacterial cells onto erythrocytes and yeast cells was developed to isolate homogeneous subpopulations (S-fimbriated, type-1-fimbriated, and non-fimbriated) of. E. coli. The level of contamination in each isolated subpopulation was 4% at the highest. The method is useful in obtaining homogeneous bacterial populations for adherence studies and for purification of specific fimbrial antigens.     

The immunological status of breast cancer patients during treatment with a new antiestrogen,toremifene

Summary The immune status of breast cancer patients was followed during antiestrogen treatment for at least 1 year or until progression of the disease. Twelve postmenopausal women with advanced estrogen-receptor-positive breast cancer were treated with a novel antiestrogen, toremifene. Immune functions were determined before the start of the treatment and at 3, 6, and 12 months. For NK cell cytotoxicity testing there were 74 healthy controls and for T cell subset measurements 28 healthy controls. No statistically significant changes in the T cell subsets or NK cell cytotoxicity were observed during treatment. However, throughout toremifene treatment patients had fewer CD4 cells (T helper lymphocytes) than did the controls. Cancer patients had higher pretreatment B cell values than the controls,P = 0.01, but during the first months of toremifene treatment B cell values decreased and remained within the normal range thereafter. A positive effect on mitogen-stimulation tests with phytohemagglutinin (PHA) and concanavalin A (ConA) was observed during the first months of treatment (P = 0.01 for PHA and 0.03 for log [ConA] and a stabilization at the higher level thereafter. These results indicate that toremifene has a stimulatory effect on cell-mediated immunity in breast cancer patients.