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T Kiss

Publications and source records attributed to T Kiss.

At least 91 records · Page 5Linked to original sources
PubMed1995

Distribution of catch-relaxing peptide (CARP)-like immunoreactive neurons in the central and peripheral nervous system of Helix pomatia.

Immunocytochemistry was performed on the nervous system of Helix by the use of an antibody raised against a myotropic neuropeptide, the catch-relaxing peptide (CARP), isolated from Mytilus edulis. In each ganglion of the central nervous system of Helix pomatia, numerous CARP-immunoreactive cell bodies and a dense immunoreactive fiber system could be observed with a dominancy in the cerebral and pedal ganglia. The majority of the immunoreactive neurons are unipolar, although multipolar neurons also occur. In the neuropil areas, CARP-immunoreactive fibers show extensive arborization, which may indicate a central role of CARP. CARP-immunoreactive elements could be observed in each investigated peripheral nerve and peripheral areas, namely in the intestine, heart, aorta, buccal mass, lips, and foot. However, CARP-immunoreactive cell bodies could only be demonstrated in the intestine and the foot musculature. Thin varicose CARP-immunoreactive fibers were observed over both muscle and gland cells in the different peripheral organs, suggesting a peripheral role of CARP. In vivo CARP injection into the body cavity (10(-3), 10(-4), 10(-5) M) altered the general behavioral state of the animals and induced the relaxation of the musculature of the whole body wall indicating that CARP has a significant role in the regulation of muscle contraction.

Amino Acid Sequence↗
PubMed1995

Tachykinin- and leucokinin-related peptides in the molluscan nervous system.

Distribution of locustatachykinin-like immunoreactive (LomTKLI) and leucokinin like immunoreactive (LKLI) neurons in the central nervous system (CNS) of the pond snail, Lymnaea stagnalis was investigated and compared to that found in Helix pomatia. Occurrence of LomTKLI neurons in different ganglia of the freshwater bivalve, Anodonta cygnea, was also studied. Similar to Helix, the Lymnaea CNS contained LomTKLI and LKLI neurons mainly in the cerebral and pedal ganglia, but the number of labelled neurons was found to be significantly lower in Lymnaea (150-184 LomTKLI and 86-104 LKLI neurons). LomTKLI elements in anodonta ganglia were mainly confined to the neuropil, whereas the immunostained perikarya were only randomly distributed. LomTKLI and LKLI neurons were also demonstrated in a similar pattern of distribution in the intestine of Lymnaea and Helix. Analyzing the membrane effects of locustatachykinin-I, leucokinin-I and anodontatachykinin, Helix neurons were found to be either depolarized or hyperpolarized. Voltage-clamp experiments revealed the role of Ca- or K-currents in peptide effects. Our results indicate that the different tachykinin- and leucokinin-systems are involved in different central and peripheral regulatory processes of the molluscan nervous system.

Animals↗
PubMed1994

Metal ion-induced permeability changes in cell membranes: a minireview.

1. The paper summarizes the effects of the metal ions Cu2+, Pb2+, Ag+, Hg2+, Zn2+, and Cd2+ applied externally or internally to the surface membrane of different excitable cells. 2. Conductance changes induced by metal ions, and metal ion-activated current, are compared with respect to their ion and voltage dependence. 3. It is suggested that metal ion-induced effects can be realized through special structures of the cell membrane, the metal ion "receptors," although other mechanisms, as, for example, competition for Ca-binding sites in the channel forming proteins, cannot be excluded.

Animals↗
PubMed1994

The effect of acetylcholine and serotonin on calcium transients and calcium currents in identified Helix pomatia L. neurons.

The results presented demonstrate that in D neurons of the snail Helix pomatia L., acetylcholine (ACh) (10 divided by 100 microM) and serotonin (5-HT) (0.1 divided by 1000 microM) applications reduce both the basal intracellular concentration level ([Ca2+]in) and the amplitudes of calcium transients induced by membrane depolarization. It is likely that the mechanism of [Ca2+]in changes in the suppression of calcium inward currents (ICa). Influences of Ach and 5-HT on ICa were studied. Both effects were dose-dependent (ACh--0.01 divided by 100 microM and 5-HT--0.1 divided by 1000 microM). The half-maximal effects (IC50) were evoked by ACh concentration of 0.15 microM and 5-HT--15 microM. Furthermore we have also shown that in some cells 5-HT could evoke a transient increase in ICa (IC50 = 2 microM). The effects of Ach and 5-HT were nonadditive--the subsequent application of ACh after 5-HT, and vice versa, produced no inhibitory effects. This may indicate that both substances act through a common intermediate (possibly, G-protein).

Acetylcholine↗
PubMed1993

Activity of U-snRNA genes with modified placement of promoter elements in transfected protoplasts and stably transformed tobacco.

In higher plants the promoter elements of pol II- and pol III-transcribed U-snRNA genes are identical, comprising a -30 TATA box and an upstream sequence element, USE. The USE and TATA are centred approximately four and three helical DNA turns apart in pol II and pol III genes, respectively, and it is this difference in the element spacing that determines the RNA polymerase specificity of the gene. In this study we have analyzed the effect of spacing mutations on activity of Arabidopsis U2 and U6 genes in transfected protoplasts of Nicotiana plumbaginifolia and in stably transformed tobacco. In the pol III-transcribed U6 gene the insertions and deletions of either odd or even numbers of half helical turns completely inactivate transcription in transfected protoplasts, consistent with the high conservation of the element spacing found in all plant U-snRNA genes. Surprisingly, while insertions of 50 base pairs (bp) or more into the spacer of the pol II-specific U2 gene inactivate transcription, a deletion of 5 bp or insertions of as much as 20 bp decrease transcription by only 40 to 70%. This relaxed requirement for the conserved element spacing is only seen in transfected protoplasts since the same mutant U2 genes are not transcribed in stably transformed tobacco when transcription takes place from the chromosome. The results provide some clues about possible factor interactions at the promoters of plant U-snRNA genes and also offer an example of major differences in transcription between transiently and stably transformed cells.

Arabidopsis↗
PubMed1993

Small nucleolar RNAs encoded by introns of the human cell cycle regulatory gene RCC1.

Eukaryotic cells contain a large number of U small nuclear RNAs (U-snRNAs) involved in various RNA processing reactions in the nucleoplasm and nucleous. Most of the U-snRNAs have 5'-terminal caps added to the end of the primary transcript. Here we describe two variants of a snRNA, called U17, identified in human HeLa cells. U17 RNA may be involved in ribosome biogenesis since it is found in the nucleolus and sediments with 40S structures possibly representing nascent ribosomal subunits. U17 RNAs contain no cap but have a monophosphate at the 5'-terminus indicating that they are processed from longer precursors. The U17 RNAs are encoded within introns 1 and 2 of the single copy gene RCC1 which codes for an important cell cycle regulatory protein. In HeLa cell S-100 extract, U17 RNA is faithfully excised from a longer RNA transcript derived from the intron yielding 5'-monophosphorylated RNA. These data suggest that U17 RNAs are not independently transcribed but are processed out of the RCC1 pre-mRNA or out of the spliced introns.

Base Sequence↗
PubMed1993

Both Arabidopsis TATA binding protein (TBP) isoforms are functionally identical in RNA polymerase II and III transcription in plant cells: evidence for gene-specific changes in DNA binding specificity of TBP.

Promoters of pol II and pol III transcribed U-snRNA genes in plants have identical sequence elements comprised of a -30 TATA box and an upstream sequence element (USE), located four or three helical turns upstream of the TATA box in pol II and pol III genes, respectively; it is this difference in element spacing that determines the RNA polymerase specificity of the gene. We are interested in identifying factors binding to U-snRNA gene promoters and their role in selection of RNA polymerase. In this work we have investigated possible differences in the activity of the two TATA binding proteins (TBPs) encoded by two different TBP genes of Arabidopsis. Using mutant TBPs with altered DNA binding specificity, similar to those described previously in yeast, we show that two Arabidopsis TBP isoforms are equally active with both pol II and pol III U-snRNA genes and with an mRNA gene transfected into plant protoplasts. In contrast to yeast, where modified TBP permits transcription only from promoters containing the TGTAAA mutant of the consensus (TATAAA) TATA element, altered Arabidopsis TBPs also suppress other TATA box mutants. Similar results were obtained with human and yeast TBP mutants expressed in plant cells. Interestingly, in several cases suppression of different TATA box mutants by altered TBPs was gene or RNA polymerase specific suggesting that assembly of TBP into specific complexes containing different TBP-associated factors may alter DNA binding specificity of the protein.

Amino Acid Sequence↗
PubMed1993

Patch-clamp studies of the oxytocin-induced effects in Helix pomatia L. neurons.

Effect of extracellularly applied oxytocin was investigated on snail neurons in cell attached single channel recording configuration. OXT activated Cl-dependent inward and outward current with amplitude of 1.4 and 1.6 pA, respectively. OXT have affected the ACh-activated current decreasing or increasing the mean interburst interval of single channel activity.

Acetylcholine↗
PubMed1993

[Analytical and stability studies carried out during the formulation development of Hevizos ointment].

BIOGAL Pharmaceutical Works Ltd. had started to develop an antiviral ointment named Hevizos in 1984, which was then registered as a drug in 1987. In this paper results of the developing work of the test analytical methods for both the raw material epervudine and the ointment itself are reported. To assay the active ingredient and to detect the impurities a high performance liquid chromatographic method elaborated by Central Chemical Research Institute (Budapest, Hungary) was adapted and validated by BIOGAL. The method was tested for applicability for studying the stability of the active ingredient and the preparation. It was established that epervudine decomposes in acidic medium the final product being isopropyl-uracil. Wide-ranging stability test were performed in order to form a suitable packaging, to establish the storage conditions and to determine expiration time of Hevizos ointment. Further stability studies are under progress on the preparation with modified tropic-resistant packaging.

Antiviral Agents↗
PubMed1992

Cap structure of U3 small nucleolar RNA in animal and plant cells is different. gamma-Monomethyl phosphate cap structure in plant RNA.

U3 small nucleolar RNA (snoRNA) is an abundant small RNA involved in the processing of pre-ribosomal RNA of eukaryotic cells. U3 snoRNA has been previously characterized from several sources, including human, rat, mouse, frog, fruit fly, dinoflagellates, slime mold, and yeast; in all these organisms, U3 snoRNA contains trimethylguanosine cap structure. In all instances where investigated, the trimethylguanosine-capped snRNAs including U3 snoRNA, are synthesized by RNA polymerase II. However, in higher plants, the U3 snoRNA is synthesized by RNA polymerase III and contains a cap structure different from trimethylguanosine (Kiss, T., and Solymosy, F. (1990) Nucleic Acids Res. 18, 1941-1949; Marshallsay, C., Kiss, T., and Filipowicz, W. (1990) Nucleic Acids Res. 18, 3451-3458; Kiss, T., Marshallsay, C., and Filipowicz, W. (1991) Cell 65, 517-526). In this study, we present evidence that cowpea and, most likely, tomato plant U3 snoRNA contains a methyl-pppA cap structure. These data show that the same U3 snoRNA contains different cap structures in different species and suggest that the kind of cap structure that an uridylic acid-rich small nuclear RNA contains is dependent on the RNA polymerase responsible for its synthesis. In vitro synthesized plant U3 snoRNA, with pppA or pppG as its 5' end, was converted to methyl-pppA/G cap structure in vitro when incubated with extracts prepared from wheat germ or HeLa cells. These data show that the capping machinery is conserved in organisms as evolutionarily distant as plants and mammals. Nucleotides 1-45 of tomato U3 snoRNA, which are capable of forming a stem-loop structure, are sufficient to direct the methyl cap formation in vitro.

Animals↗