Transitions in nutation trajectory geometry in peppermint (Mentha x piperita L.) with respect to lunisolar acceleration.

Nutations of plant organs are significantly affected by the circatidal modulation in the gravitational force exerted by the Moon and Sun (lunisolar tidal acceleration, Etide). In a previous study on nutational rotations of stem apices, we observed abrupt alterations in their direction and irregularities of the recorded trajectories. Such transitions have not yet been analysed in detail. Peppermint plants were continuously recorded with time-lapse photography and aligned with contemporaneous time courses of the Etide estimates. Each nutational stem tip movement path was assigned to one of two groups, depending on its geometry, as: (i) regular elliptical movements and (ii) irregular movements (with a random type of trajectory). Analyses of the correlation between the plant nutation trajectory parameters and Etide, as well as of the trajectory geometry of the individual plants were performed. The trajectory geometry of young mint stem apices was related to the velocity of the apex rotation and significantly affected by the gravitational force estimated from the Etide. A low velocity of nutational movement, associated with the random character of the trajectory, usually occurred simultaneously with local minima or maxima of Etide. As the mint plant ages, the transitions in the stem tip trajectory were limited; no correspondence with Etide dynamics was observed. The results indicate that the plant tip geometry path transitions with respect to the changing gradient of lunisolar tidal acceleration could be interpreted as manifestation of a continuous accommodation of the shoot apical part to the state of minimum energy dissipation.

The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe.

Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens probe, launched from the Cassini spacecraft, has made the first direct observations of the satellite's surface and lower atmosphere. Here we report direct atmospheric measurements from the Gas Chromatograph Mass Spectrometer (GCMS), including altitude profiles of the constituents, isotopic ratios and trace species (including organic compounds). The primary constituents were confirmed to be nitrogen and methane. Noble gases other than argon were not detected. The argon includes primordial 36Ar, and the radiogenic isotope 40Ar, providing an important constraint on the outgassing history of Titan. Trace organic species, including cyanogen and ethane, were found in surface measurements.

Oxygen ions observed near Saturn's A ring.

Ions were detected in the vicinity of Saturn's A ring by the Ion and Neutral Mass Spectrometer (INMS) instrument onboard the Cassini Orbiter during the spacecraft's passage over the rings. The INMS saw signatures of molecular and atomic oxygen ions and of protons, thus demonstrating the existence of an ionosphere associated with the A ring. A likely explanation for these ions is photoionization by solar ultraviolet radiation of neutral O2 molecules associated with a tenuous ring atmosphere. INMS neutral measurements made during the ring encounter are dominated by a background signal.

Prediction of DNA single-strand conformation polymorphism: analysis by capillary electrophoresis and computerized DNA modeling.

We have analyzed previously three representative p53 single-point mutations by capillary-electrophoresis single-strand conformation polymorphism (CE-SSCP). In the current study, we compared our CE-SSCP results with the potential secondary structures predicted by an RNA/DNA-folding algorithm with DNA energy rules, used in conjunction with a computer analysis workbench called STRUCTURELAB. Each of these mutations produces measurable shifts in CE migration times relative to wild type. Using computerized folding analysis, each of the mutations was found to have a conformational difference relative to wild type, which accounts for the observed differences in CE migration. Additional properties exhibited in the CE electropherograms were also explained using the computerized analysis. These include the appearance of secondary peaks and the temperature dependence of the electrophoretic patterns. The results yield insight into the mechanism of SSCP and how the conditions of this measurement, especially temperature, may be optimized to improve the sensitivity of the SSCP method. The results may also impact other diagnostic methods, which would benefit by a better understanding of DNA single-strand conformation polymorphisms to optimize conditions for enzymatic cleavage and DNA hybridization reactions.

RNA folding pathway functional intermediates: their prediction and analysis.

The massively parallel genetic algorithm (GA) for RNA structure prediction uses the concepts of mutation, recombination, and survival of the fittest to evolve a population of thousands of possible RNA structures toward a solution structure. As described below, the properties of the algorithm are ideally suited to use in the prediction of possible folding pathways and functional intermediates of RNA molecules given their sequences. Utilizing Stem Trace, an interactive visualization tool for RNA structure comparison, analysis of not only the solution ensembles developed by the algorithm, but also the stages of development of each of these solutions, can give strong insight into these folding pathways. The GA allows the incorporation of information from biological experiments, making it possible to test the influence of particular interactions between structural elements on the dynamics of the folding pathway. These methods are used to reveal the folding pathways of the potato spindle tuber viroid (PSTVd) and the host killing mechanism of Escherichia coli plasmid R1, both of which are successfully explored through the combination of the GA and Stem Trace. We also present novel intermediate folds of each molecule, which appear to be phylogenetically supported, as determined by use of the methods described below.

[The history of internal medicine in Poznan from the year 1919]. / Dzieje szpitalnictwa poznanskiego w zakresie chorób wewnetrznych od 1919 roku.

After the 1st World War (1914-1918) the greatest influences in the development of internal medicine were the foundation of Poznán University and its first Dean Prof. H. Swiecicki - a physician. Due to cooperation with Prof. A. Wrzosek the School of Medicine was created. In addition to those mentioned above were the first creators of internal medicine Professors: W. Jezierski, J. Lubieniecki and I. Hoffmann. During World War II Poznan medicine suffered badly. After the War there was a renewal of Poznan and in internal medicine appeared excellent leaders: prof. J. Roguski, prof. S. Kwasniewski and prof. F. Labendzinski. Thanks to them 1st 2nd and 3rd Departments of Internal Medicine transformed in narrow specialized departments integrated in the Institute of Internal Disease and led by prof. K. Jasinski and his vice head prof. J. Hasik and prof. M. Gembicki. In the 1985 there appeared from Internal Institute the Institute of Cardiology with the head prof. A. Cieslinski. There was also overworked the status of out-clinic internal medicine (prof. I. Zimmerman-Górska, dr W. P. Kasprzak).

Stem Trace: an interactive visual tool for comparative RNA structure analysis.

MOTIVATION: Stem Trace is one of the latest tools available in STRUCTURELAB, an RNA structure analysis computer workbench. The paradigm used in STRUCTURELAB views RNA structure determination as a problem of dealing with a database of a large number of computationally generated structures. Stem Trace provides the capability to analyze this data set in a novel, visually driven, interactive and exploratory way. In addition to providing graphs at a high level of ion, it is also connected with complementary visualization tools which provide orthogonal views of the same data, as well as drawing of structures represented by a stem trace. Thus, on top of being an analysis tool, Stem Trace is a graphical user interface to an RNA structural information database. RESULTS: We illustrate Stem Trace's capabilities with several examples of the analysis of RNA folding data performed on 24 strains of HIV-1, HIV-2 and SIV sequences around the HIV dimerization region. This dimer linkage site has been found to play a role in encapsidation, reverse transcription, recombination, and inhibition of translation. Our examples show how Stem Trace elucidates preservation of structures in this region across the various strains of HIV. AVAILABILITY: The program can be made available upon request. It runs on SUN, SGI and DEC (Compaq) Unix workstations.

Chemical composition measurements of the atmosphere of Jupiter with the Galileo Probe mass spectrometer.

The Galileo Probe entered the atmosphere of Jupiter on December 7, 1995. Measurements of the chemical and isotopic composition of the Jovian atmosphere were obtained by the mass spectrometer during the descent over the 0.5 to 21 bar pressure region over a time period of approximately 1 hour. The sampling was either of atmospheric gases directly introduced into the ion source of the mass spectrometer through capillary leaks or of gas, which had been chemically processed to enhance the sensitivity of the measurement to trace species or noble gases. The analysis of this data set continues to be refined based on supporting laboratory studies on an engineering unit. The mixing ratios of the major constituents of the atmosphere hydrogen and helium have been determined as well as mixing ratios or upper limits for several less abundant species including: methane, water, ammonia, ethane, ethylene, propane, hydrogen sulfide, neon, argon, krypton, and xenon. Analysis also suggests the presence of trace levels of other 3 and 4 carbon hydrocarbons, or carbon and nitrogen containing species, phosphine, hydrogen chloride, and of benzene. The data set also allows upper limits to be set for many species of interest which were not detected. Isotope ratios were measured for 3He/4He, D/H, 13C/12C, 20Ne/22Ne, 38Ar/36Ar and for isotopes of both Kr and Xe.

The composition of the Jovian atmosphere as determined by the Galileo probe mass spectrometer.

The Galileo probe mass spectrometer determined the composition of the Jovian atmosphere for species with masses between 2 and 150 amu from 0.5 to 21.1 bars. This paper presents the results of analysis of some of the constituents detected: H2, He, Ne, Ar, Kr, Xe, CH4, NH3, H2O, H2S, C2 and C3 nonmethane hydrocarbons, and possibly PH3 and Cl. 4He/H2 in the Jovian atmosphere was measured to be 0.157 +/- 0.030. 13C/C12 was found to be 0.0108 +/- 0.0005, and D/H and 3He/4He were measured. Ne was depleted, < or = 0.13 times solar, Ar < or = 1.7 solar, Kr < or = 5 solar, and Xe < or = 5 solar. CH4 has a constant mixing ratio of (2.1 +/- 0.4) x 10(-3) (12C, 2.9 solar), where the mixing ratio is relative to H2. Upper limits to the H2O mixing ratio rose from 8 x 10(-7) at pressures <3.8 bars to (5.6 +/- 2.5) x 10(-5) (16O, 0.033 +/- 0.015 solar) at 11.7 bars and, provisionally, about an order of magnitude larger at 18.7 bars. The mixing ratio of H2S was <10(-6) at pressures less than 3.8 bars but rose from about 0.7 x 10(-5) at 8.7 bars to about 7.7 x 10(-5) (32S, 2.5 solar) above 15 bars. Only very large upper limits to the NH3 mixing ratio have been set at present. If PH3 and Cl were present, their mixing ratios also increased with pressure. Species were detected at mass peaks appropriate for C2 and C3 hydrocarbons. It is not yet clear which of these were atmospheric constituents and which were instrumentally generated. These measurements imply (1) fractionation of 4He, (2) a local, altitude-dependent depletion of condensables, probably because the probe entered the descending arm of a circulation cell, (3) that icy planetesimals made significant contributions to the volatile inventory, and (4) a moderate decrease in D/H but no detectable change in (D + 3He)/H in this part of the galaxy during the past 4.6 Gyr.

On neural blind separation with noise suppression and redundancy reduction.

Noise is an unavoidable factor in real sensor signals. We study how additive and convolutive noise can be reduced or even eliminated in the blind source separation (BSS) problem. Particular attention is paid to cases in which the number of sensors is larger than the number of sources. We propose various methods and associated adaptive learning algorithms for such an extended BSS problem. Performance and validity of the proposed approaches are demonstrated by extensive computer simulations.

STRUCTURELAB: a heterogeneous bioinformatics system for RNA structure analysis.

STRUCTURELAB is a computational system that has been developed to permit the use of a broad array of approaches for the analysis of the structure of RNA. The goal of the development is to provide a large set of tools that can be well integrated with experimental biology to aid in the process of the determination of the underlying structure of RNA sequences. The approach taken views the structure determination problem as one of dealing with a database of many computationally generated structures and provides the capability to analyze this data set from different perspectives. Many algorithms are integrated into one system that also utilizes a heterogeneous computing approach permitting the use of several computer architectures to help solve the posed problems. These different computational platforms make it relatively easy to incorporate currently existing programs as well as newly developed algorithms and to best match these algorithms to the appropriate hardware. The system has been written in Common Lisp running on SUN or SGI Unix workstations, and it utilizes a network of participating machines defined in reconfigurable tables. A window-based interface makes this heterogeneous environment as transparent to the user as possible.

The Galileo probe mass spectrometer: composition of Jupiter's atmosphere.

The composition of the jovian atmosphere from 0.5 to 21 bars along the descent trajectory was determined by a quadrupole mass spectrometer on the Galileo probe. The mixing ratio of He (helium) to H2 (hydrogen), 0.156, is close to the solar ratio. The abundances of methane, water, argon, neon, and hydrogen sulfide were measured; krypton and xenon were detected. As measured in the jovian atmosphere, the amount of carbon is 2.9 times the solar abundance relative to H2, the amount of sulfur is greater than the solar abundance, and the amount of oxygen is much less than the solar abundance. The neon abundance compared with that of hydrogen is about an order of magnitude less than the solar abundance. Isotopic ratios of carbon and the noble gases are consistent with solar values. The measured ratio of deuterium to hydrogen (D/H) of (5 +/- 2) x 10(-5) indicates that this ratio is greater in solar-system hydrogen than in local interstellar hydrogen, and the 3He/4He ratio of (1.1 +/- 0.2) x 10(-4) provides a new value for protosolar (solar nebula) helium isotopes. Together, the D/H and 3He/4He ratios are consistent with conversion in the sun of protosolar deuterium to present-day 3He.

[Viruses of parasitic protozoa]. / Wirusy pasozytniczych pierwotniaków.

The authors present the actual review on several publications concerning the molecular characterizations of the viruses found in parasitic protozoa such as Giardia, Trichomonas, Leishmania and Entamoeba histolytica. All of the RNA viruses observed in parasitic protozoa showed several similarities and did not considerably differ from the viruses found in simple eukaryotic cells; they closely correspond to dsRNA viruses of yeast. The supposition that the protozoan symbionts detected in laboratories transfer to their hosts in natural conditions seemed to be rational, though, there are no evidences that these symbionts are potential pathogens. However, the opinion reiterates that intestinal protozoa (e.g. Entamoeba histolytica) may serve as vectors for HIV or cofactors of HIV infection. The authors point out that irrespective of the potential role of viruses as vectors in the transfection system for parasitic protozoa, the observed viral system constitutes an unusual experimental system to solve the problems of gene expression.

[Cryptosporidiosis--a typical environmental parasitosis]. / Kryptosporydioza--parazytoza o typowym uwarunkowaniu srodowiskowym.

The article reviews the problems on epidemiology of cryptosporidiosis and gives a detailed description of the massive waterborne outbreak in Milwaukee (Wisconsin, USA) associated with a break in filtration capacity of a public water supply. The authors emphasize the need for high-quality diagnostic procedures as current coprodiagnostic microscopical techniques seemed to fail to detect Cryptosporidium oocysts.

[Detection of coproantigens in parasitic diseases]. / Wykrywanie koproantygenów w chorobach pasozytniczych.

The author presented general issues in detecting of parasite's coproantigens and carried out a critical review of abstracts submitted to the scientific session (17th Congress of the Polish Parasitological Society, September 1994, Gdynia, Poland). The abstracts are being published in a special edition of the "Methodical and Organisational Bulletin" (Institute of Marine and Tropical Medicine, Gdynia, Poland).

[Waterborne outbreaks of Giardia]. / Wodnopochodne epidemie Giardia.

The authors present the actual informations on waterborne outbreaks of giardiasis as well as the evidences of Giardia cyst transmission by municipal water supply. In the article a recommendations is given to molecular biology techniques which contributed to the armentarium applied in the modern diagnostics of giardiasis.

[Usefulness of genome analysis methods for diagnosis of giardiasis and cryptosporidiosis]. / Przydatnosc metod analizy genomu w diagnostyce giardiozy i kryptosporydiozy.

The article comprises a critical review on practical applications of molecular technology in parasitological diagnostics in a broad sense, also as a diagnosis of species and a method of epidemiological analysis. Techniques of genome analysis at different levels, as specific nucleic acid probes, DNA restriction profiles (RFLP), hybridization techniques, pulse-field gel electrophoresis, in vitro nucleic acid amplification, and DNA fingerprint technique used in studies on Giardia and Cryptosporidium were discussed. The essential reservation as far as this technology is concerned refers to its usefulness in parasitological diagnostics; there is no sense in working out methods for recognizing parasites which could otherwise be identified by well trained parasitologists and simple microscopic methods. The improved diagnosis of parasites resulting from the application of molecular technology significantly contributed to the armarium of parasitologists. Application of recent molecular technology in diagnosis of giardiasis and cryptosporidiosis may basically support clinical diagnosis which provides possibilities of early and selective treatment and makes possible epidemiological studies. These assays will permit not only a rapid diagnosis and exact differentiation but will also enable a better recognition of Giardia and Cryptosporidium genome organization. However, in spite of the wide availability of this new techniques they have not been fully applied--as yet--in diagnosis and in epidemiological studies on these parasites. The authors share the opinion of Busch (1991) on the need of proper recognition of high-quality and rigorous work in employing new molecular assays, because their wide availability and high sensitivity could cause "false-positive" results by contamination with amplified DNA sequences.(ABSTRACT TRUNCATED AT 250 WORDS)

[Amebic keratitis-keratitis acanthamoeba]. / Pelzakowe zapalenie rogówki--keratitis acanthamoebica.

In seventeen patients who suffered of corneal ulcer, and were negative in bacteriological and mycological examinations, parasitological tests were performed between 1990-1992. Acanthamoeba keratitis was diagnosed in one patient with characteristic corneal changes of right eye following trauma. The patient was not a contact lens wearer. The amoeba found in direct smears of scraping from corneal ulcer and isolated and cloned in in vitro conditions (isolate-clone-No. 2961) belonged to Acanthamoeba polyphaga species. The trophozoites showed a low degree of invasiveness and high virulence when tested in BALB/c mice. The authors discussed the epidemiology of Acanthamoeba keratitis and pointed out to the necessity of accurate laboratory diagnosis and discerning interpretation of the results to prevent an Acanthamoeba-phobia among the potential patients and most of all among the medical staff.

Comparison of Giardia isolates from different laboratories by isoenzyme analysis and recombinant DNA probes.

A total of 13 new Giardia isolates were established in axenic culture. All of the new isolates were obtained by excystation of Giardia cysts from the feces of patients in Dutch hospitals. These isolates were subjected to isoenzyme and DNA analysis together with isolates from Poland, Belgium, and various other parts of the world. Isoenzyme analysis revealed that nearly all of the newly established isolates exhibited unique zymodemes. Isolates obtained from individuals from Belgium and Poland, on the other hand, displayed single zymodemes. Genomic DNA libraries were constructed from isolates belonging to the latter two zymodemes; specific and common recombinant DNA clones were selected from these libraries. Differential screening revealed that the two isolates had only 80% of the clones in common. Restriction-fragment-length polymorphism analysis using three different probes together with two synthetic probes that are complementary to Giardia structural protein genes led to the separation of all isolates into two major groups; within these groups, a further division could be made by application of other techniques or probes. The results of DNA analysis and zymodeme classification were in general agreement; in the present report they are compared with the data in the literature and discussed.