Amphibian Proteins: Proteins obtained from species in the class of AMPHIBIANS.Amphibians: VERTEBRATES belonging to the class amphibia such as frogs, toads, newts and salamanders that live in a semiaquatic environment.Chytridiomycota: A phylum of fungi that was formerly considered a subdivision of Phycomycetes. They are the only fungi that produce motile spores (zoospores) at some stage in their life cycle. Most are saprobes but they also include examples of plant, animal, and fungal pathogens.Ranidae: The family of true frogs of the order Anura. The family occurs worldwide except in Antarctica.Anura: An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.Bufonidae: The family of true toads belonging to the order Anura. The genera include Bufo, Ansonia, Nectophrynoides, and Atelopus.Urodela: An order of the Amphibia class which includes salamanders and newts. They are characterized by usually having slim bodies and tails, four limbs of about equal size (except in Sirenidae), and a reduction in skull bones.Salamandridae: A family of Urodela consisting of 15 living genera and about 42 species and occurring in North America, Europe, Asia, and North Africa.Ambystoma: A genus of the Ambystomatidae family. The best known species are the axolotl AMBYSTOMA MEXICANUM and the closely related tiger salamander Ambystoma tigrinum. They may retain gills and remain aquatic without developing all of the adult characteristics. However, under proper changes in the environment they metamorphose.Ranavirus: A genus of IRIDOVIRIDAE which infects fish, amphibians and reptiles. It is non-pathogenic for its natural host, Rana pipiens, but is lethal for other frogs, toads, turtles and salamanders. Frog virus 3 is the type species.Ambystoma mexicanum: A salamander found in Mexican mountain lakes and accounting for about 30 percent of the urodeles used in research. The axolotl remains in larval form throughout its life, a phenomenon known as neoteny.Reptiles: Cold-blooded, air-breathing VERTEBRATES belonging to the class Reptilia, usually covered with external scales or bony plates.Amphibian Venoms: Venoms produced by frogs, toads, salamanders, etc. The venom glands are usually on the skin of the back and contain cardiotoxic glycosides, cholinolytics, and a number of other bioactive materials, many of which have been characterized. The venoms have been used as arrow poisons and include bufogenin, bufotoxin, bufagin, bufotalin, histrionicotoxins, and pumiliotoxin.Triturus: A genus of aquatic newts in the Salamandridae family. During breeding season many Triturus males have a dorsal crest which also serves as an accessory respiratory organ. One of the common Triturus species is Triturus cristatus (crested newt).Xenopus laevis: The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.Metamorphosis, Biological: Profound physical changes during maturation of living organisms from the immature forms to the adult forms, such as from TADPOLES to frogs; caterpillars to BUTTERFLIES.Bufo arenarum: A species of the true toads, Bufonidae, found in South America.Rana pipiens: A highly variable species of the family Ranidae in Canada, the United States and Central America. It is the most widely used Anuran in biomedical research.Xenopus: An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.Bufo marinus: A species of the true toads, Bufonidae, becoming fairly common in the southern United States and almost pantropical. The secretions from the skin glands of this species are very toxic to animals.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.MycosesRana catesbeiana: A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.Ponds: Inland bodies of standing FRESHWATER usually smaller than LAKES. They can be man-made or natural but there is no universal agreement as to their exact size. Some consider a pond to be a small body of water that is shallow enough for sunlight to reach the bottom.Animal DiseasesNotophthalmus viridescens: A species of newt in the Salamandridae family in which the larvae transform into terrestrial eft stage and later into an aquatic adult. They occur from Canada to southern United States. Viridescens refers to the greenish color often found in this species.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.Endangered Species: An animal or plant species in danger of extinction. Causes can include human activity, changing climate, or change in predator/prey ratios.DNA Virus InfectionsOocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Cell Nucleolus: Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Proto-Oncogene Proteins c-myc: Cellular DNA-binding proteins encoded by the c-myc genes. They are normally involved in nucleic acid metabolism and in mediating the cellular response to growth factors. Elevated and deregulated (constitutive) expression of c-myc proteins can cause tumorigenesis.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Dental Enamel Proteins: The proteins that are part of the dental enamel matrix.Amelogenesis: The elaboration of dental enamel by ameloblasts, beginning with its participation in the formation of the dentino-enamel junction to the production of the matrix for the enamel prisms and interprismatic substance. (Jablonski, Dictionary of Dentistry, 1992).Amelogenin: A major dental enamel-forming protein found in mammals. In humans the protein is encoded by GENES found on both the X CHROMOSOME and the Y CHROMOSOME.Ameloblasts: Cylindrical epithelial cells in the innermost layer of the ENAMEL ORGAN. Their functions include contribution to the development of the dentinoenamel junction by the deposition of a layer of the matrix, thus producing the foundation for the prisms (the structural units of the DENTAL ENAMEL), and production of the matrix for the enamel prisms and interprismatic substance. (From Jablonski's Dictionary of Dentistry, 1992)Dental Enamel: A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)Amelogenesis Imperfecta: A clinically and genetically heterogeneous group of hereditary conditions characterized by malformed DENTAL ENAMEL, usually involving DENTAL ENAMEL HYPOPLASIA and/or TOOTH HYPOMINERALIZATION.Hybridomas: Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Multiple Myeloma: A malignancy of mature PLASMA CELLS engaging in monoclonal immunoglobulin production. It is characterized by hyperglobulinemia, excess Bence-Jones proteins (free monoclonal IMMUNOGLOBULIN LIGHT CHAINS) in the urine, skeletal destruction, bone pain, and fractures. Other features include ANEMIA; HYPERCALCEMIA; and RENAL INSUFFICIENCY.Mice, Inbred BALB CAntibody Specificity: The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.

Studies of the role of endothelium-dependent nitric oxide release in the sustained vasodilator effects of corticotrophin releasing factor and sauvagine. (1/270)

1. The mechanisms of the sustained vasodilator actions of corticotrophin-releasing factor (CRF) and sauvagine (SVG) were studied using rings of endothelium de-nuded rat thoracic aorta (RTA) and the isolated perfused rat superior mesenteric arterial vasculature (SMA). 2. SVG was approximately 50 fold more potent than CRF on RTA (EC40: 0.9 +/- 0.2 and 44 +/- 9 nM respectively, P < 0.05), and approximately 10 fold more active in the perfused SMA (ED40: 0.05 +/- 0.02 and 0.6 +/- 0.1 nmol respectively, P < 0.05). Single bolus injections of CRF (100 pmol) or SVG (15 pmol) in the perfused SMA caused reductions in perfusion pressure of 23 +/- 1 and 24 +/- 2% that lasted more than 20 min. 3. Removal of the endothelium in the perfused SMA with deoxycholic acid attenuated the vasodilatation and revealed two phases to the response; a short lasting direct action, and a sustained phase which was fully inhibited. 4. Inhibition of nitric oxide synthase with L-NAME (100 microM) L-NMMA (100 microM) or 2-ethyl-2-thiopseudourea (ETPU, 100 microM) had similar effects on the vasodilator responses to CRF as removal of the endothelium, suggesting a pivotal role for nitric oxide. However the selective guanylate cyclase inhibitor 1H-[l,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ, 10 microM) did not affect the response to CRF. 5. High potassium (60 mM) completely inhibited the vasodilator response to CRF in the perfused SMA, indicating a role for K channels in this response. 6. Compared to other vasodilator agents acting via the release of NO, the actions of CRF and SVG are strikingly long-lasting, suggesting a novel mechanism of prolonged activation of nitric oxide synthase.  (+info)

Primary structure of a visual pigment in bullfrog green rods. (2/270)

In frog retina there are special rod photoreceptor cells ('green rods') with physiological properties similar to those of typical vertebrate rods ('red rods'). A cDNA fragment encoding the putative green rod visual pigment was isolated from a retinal cDNA library of the bullfrog, Rana catesbeiana. Its deduced amino acid sequence has more than 65% identity with those of blue-sensitive cone pigments such as chicken blue and goldfish blue. Antisera raised against its C-terminal amino acid sequence recognized green rods. It is concluded that bullfrog green rods contain a visual pigment which is closely related to the blue-sensitive cone pigments of other non-mammalian vertebrates.  (+info)

Molecular modeling of single polypeptide chain of calcium-binding protein p26olf from dimeric S100B(betabeta). (3/270)

P26olf from olfactory tissue of frog, which may be involved in olfactory transduction or adaptation, is a Ca2+-binding protein with 217 amino acids. The p26olf molecule contains two homologous parts consisting of the N-terminal half with amino acids 1-109 and the C-terminal half with amino acids 110-217. Each half resembles S100 protein with about 100 amino acids and contains two helix-loop-helix Ca2+-binding structural motifs known as EF-hands: a normal EF-hand at the C-terminus and a pseudo EF-hand at the N-terminus. Multiple alignment of the two S100-like domains of p26olf with 18 S100 proteins indicated that the C-terminal putative EF-hand of each domain contains a four-residue insertion when compared with the typical EF-hand motifs in the S100 protein, while the N-terminal EF-hand is homologous to its pseudo EF-hand. We constructed a three-dimensional model of the p26olf molecule based on results of the multiple alignment and NMR structures of dimeric S100B(betabeta) in the Ca2+-free state. The predicted structure of the p26olf single polypeptide chain satisfactorily adopts a folding pattern remarkably similar to dimeric S100B(betabeta). Each domain of p26olf consists of a unicornate-type four-helix bundle and they interact with each other in an antiparallel manner forming an X-type four-helix bundle between the two domains. The two S100-like domains of p26olf are linked by a loop with no steric hindrance, suggesting that this loop might play an important role in the function of p26olf. The circular dichroism spectral data support the predicted structure of p26olf and indicate that Ca2+-dependent conformational changes occur. Since the C-terminal putative EF-hand of each domain fully keeps the helix-loop-helix motif having a longer Ca2+-binding loop, regardless of the four-residue insertion, we propose that it is a new, novel EF-hand, although it is unclear whether this EF-hand binds Ca2+. P26olf is a new member of the S100 protein family.  (+info)

The dermaseptin precursors: a protein family with a common preproregion and a variable C-terminal antimicrobial domain. (4/270)

Preprodermaseptins are a group of antimicrobial peptide precursors found in the skin of a variety of frog species. Precursors of this family have very similar N-terminal preprosequences followed by markedly different C-terminal domains that correspond to mature antimicrobial peptides. Some of these peptides are 24-34 amino acids long and form well-behaved amphipathic alpha-helices, others are disulfide-linked peptides of 20-46 residues, still others, highly hydrophobic, are the smallest antimicrobial peptides known so far being only 10-13 residues in length. All these peptides are broad-spectrum microbicides that kill many bacteria, protozoa, yeasts and fungi by destroying or permeating the microbial membrane. In frogs belonging to the genus Phyllomedusinae, preprodermaseptins encoded peptides also include dermorphins and deltorphins, D-amino acid-containing heptapeptides which are very potent and specific agonists of the mu- or delta-opioid receptors. The remarkable similarity between preproregions of precursors that give rise to peptides with very different primary structures, conformations and activities suggests that the corresponding genes originate from a common ancestor. The high conservation of the precursor prepropart indicates that this region must have an important function.  (+info)

Expression and activity of cyclic and linear analogues of esculentin-1, an anti-microbial peptide from amphibian skin. (5/270)

Esculentin-1 is a potent anti-microbial peptide present in minute amounts in skin secretions of Rana esculenta. It contains 46 amino-acid residues and a C-terminal disulfide bridge. We have explored the possibility of producing analogues of this peptide by recombinant expression in Escherichia coli of a fusion protein which is sequestered in inclusion bodies. The peptide of interest has been inserted at the N-terminus of the protein, from which it can be released by cyanogen bromide cleavage. The anti-microbial activities of the recombinant peptide as well as that of a mutant linear form devoid of the disulfide bridge are presented. The recombinant analogues retain the biological activity of the natural peptide, as tested with an inhibition zone assay against a variety of microorganisms. However, experiments on the rate of bacterial killing show that gram-negative bacteria are more sensitive to the peptides than the gram-positive bacterium, the effect of the cyclic peptide being in all cases faster than that of the linear molecule. Moreover, the activity against gram-negative bacteria for both peptides is not affected by salts, whereas the activity against Staphylococcus aureus is lost at high salt concentration.  (+info)

Host defence peptides from the skin glands of the Australian blue mountains tree-frog Litoria citropa. Solution structure of the antibacterial peptide citropin 1.1. (6/270)

Nineteen citropin peptides are present in the secretion from the granular dorsal glands of the Blue Mountains tree-frog Litoria citropa; 15 of these peptides are also present in the secretion from the submental gland. Two major peptides, citropin 1.1 (GLFDVIKKVASVIGGL-NH2), citropin 1.2 (GLFDIIKKVASVVGGL-NH2) and a minor peptide, citropin 1.3 (GLFDIIKKVASVIGGL-NH2) are wide-spectrum antibacterial peptides. The amphibian has an endoprotease which deactivates these membrane-active peptides by removing residues from the N-terminal end: loss of three residues gives the most abundant degradation products. The solution structure of the basic peptide citropin 1.1 has been determined by NMR spectroscopy [in a solvent mixture of trifluoroethanol/water (1 : 1)] to be an amphipathic alpha-helix with well-defined hydrophobic and hydrophilic regions. The additional four peptides produced by the dorsal glands are structurally related to the antibacterial citropin 1 peptides but contain three more residues at their C-terminus [e.g. citropin 1.1.3 (GLFDVIKKVASVIGLASP-OH)]. These peptides show minimal antibacterial activity; their role in the amphibian skin is not known.  (+info)

Bombesin-like peptides and receptors in normal fetal baboon lung: roles in lung growth and maturation. (7/270)

Previously, we have shown that bombesin-like peptide (BLP) promotes fetal lung development in rodents and humans but mediates postnatal lung injury in hyperoxic baboons. The present study analyzed the normal ontogeny of BLP and BLP receptors as well as the effects of BLP on cultured normal fetal baboon lungs. Transcripts encoding gastrin-releasing peptide (GRP), a pulmonary BLP, were detectable on gestational day 60 (ED60), peaked on approximately ED90, and then declined before term (ED180). Numbers of BLP-immunopositive neuroendocrine cells peaked from ED80 to ED125 and declined by ED160, preceding GRP-receptor mRNAs detected from ED125 until birth. BLP (0.1-10 nM) stimulated type II cell differentiation in organ cultures as assessed by [(3)H]choline incorporation into surfactant phospholipids, electron microscopy, and increased surfactant protein (SP) A- and/or SP-C-immunopositive cells and SP-A mRNA. BLP also induced neuroendocrine differentiation on ED60. Cell proliferation was induced by GRP, peaking on ED90. Similarly, blocking BLP degradation stimulated lung growth and maturation, which was completely reversed by a BLP-specific antagonist. The dissociation between GRP and GRP-receptor gene expression during ontogeny suggests that novel BLP receptors and/or peptides might be implicated in these responses.  (+info)

The mammalian homologues of frog Bv8 are mainly expressed in spermatocytes. (8/270)

Bv8, a protein from skin secretions of Bombina variegata, reacts with receptors present in mammalian brain and intestine (Mollay et al. (1999) Eur. J. Pharmacol. 374, 189-196). As deduced from cloned cDNAs, the murine and human Bv8 homologues have identical amino-terminal sequences and also contain 10 cysteines. From mouse testes, two forms of Bv8 mRNA have been characterized, of which one contains an additional exon which codes for 21 mostly basic amino acids. The mouse Bv8 gene is most active in mid-late pachytene spermatocytes. In mouse testes, Bv8 mRNA can first be detected at the end of the second week post partum.  (+info)

  • Hormonal Proteins and Peptides, Volume IV: Growth Hormone and Related Proteins deals with various aspects of somatotropin or growth hormone, and its related proteins. (
  • Several peptides that prevent NO production by interacting with CaM have been isolated in the cutaneous secretions of Australian amphibians, and are thought to serve as a defense mechanism against predators. (
  • Double-stranded (ds) RNA, generated during viral infection, binds and activates the mammalian anti-viral protein kinase PKR, which phosphorylates the translation initiation factor eIF2α leading to the general inhibition of protein synthesis. (
  • Maturation of oocytes, without evident hormone stimulation, can be achieved in the presence or absence of the somatic cells, following activation of protein kinase C or transient exposure to a synthetic protease inhibitor (TPCK) of chymotrypsin. (
  • Mitogen-activated protein kinase activation by oxidative and bacterial stress in an amphibian cell culture model. (
  • The encoded protein is part of the integrin-linked kinase signaling complex and plays a role in cell adhesion, motility and survival. (
  • Indeed, the latter is also the parent of GO:0045736 "negative regulation of cyclin dependent protein kinase activity" , which is not adequate to describe the reaction under annotation. (
  • SAAF induces entry of extracellular Ca 2+ and an increase in intracellular cAMP in the sperm ( 15 , 16 ), which induces protein kinase A-dependent phosphorylation of 21- and 26-kDa axonemal proteins and activation of sperm motility ( 17 ). (
  • The results suggest that PCBs induce mechanisms against oxidative stress (peroxiredoxins 1 and 2), adaptative changes in the energetic metabolism (enolase 1, glycerol-3-phosphate dehydrogenase, and creatine kinase muscle and brain types), and the implication of the unfolded protein response system (glucose-regulated protein, 58 kDa). (
  • Furthermore, the experimental outcomes confirmed that the environmental alerts which convey concerning the redistribution of pigment organelles within the organism of clawed frogs are related to a change of chance with which the person motor proteins from the actin filaments change to the microtubule filaments. (
  • Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. (
  • The three modern orders of amphibians are Anura (the frogs and toads), Urodela (the salamanders), and Apoda (the caecilians). (
  • The number of known amphibian species is approximately 7,000, of which nearly 90% are frogs. (
  • The numbers of species cited above follows Frost and the total number of known amphibian species is over 7,000, of which nearly 90% are frogs. (
  • Traditionally, amphibians as a class are defined as all tetrapods with a larval stage, while the group that includes the common ancestors of all living amphibians (frogs, salamanders and caecilians) and all their descendants is called Lissamphibia. (
  • In contrast, switching between the networks is absolutely necessary among the clawed frogs so that the animal can change color - and this ability to switch has also been preserved in the further course of evolution from amphibian to higher vertebrates", explains Ökten further. (
  • Moreover, the experimental results showed that the environmental signals which bring about the redistribution of pigment organelles in the organism of clawed frogs are associated with a change of probability with which the individual motor proteins from the actin filaments switch to the microtubule filaments. (
  • In the case of poisonous amphibians, like the tropical poison dart frogs, their toxins are usually small chemicals like alkaloids that are extracted from insects and secreted onto the animal's skin. (
  • In addition, amphibians exhibit many unique features, such as very diverse body plans and limb types between frogs, salamanders and caecilians, or a wide range of genome sizes between and within the three orders. (
  • 1969. Geographic variation of blood and liver proteins in cricket frogs. (
  • Insects feast on amorous tungara frogs by eavesdropping on their amphibian love songs. (
  • Here, we used RNA sequencing and proteomics to determine how alkaloids impact mRNA or protein abundance in the little devil frog ( Oophaga sylvatica ), and compared wild-caught chemically defended frogs with laboratory frogs raised on an alkaloid-free diet. (
  • We then used proteomic approaches to quantify plasma proteins, where we found several protein abundance differences between wild and laboratory frogs, including the amphibian neurotoxin binding protein saxiphilin. (
  • These transcript and protein abundance patterns suggest that the presence of alkaloids influences frog physiology and that small molecule transport proteins may be involved in toxin bioaccumulation in dendrobatid poison frogs. (
  • In order to utilize diet-derived toxins, frogs may be resistant to alkaloids they are accumulating through mutations in target proteins. (
  • About 50 volunteers attended the event hosted by the Cumberland Land Trust to assist in the annual amphibian migration of frogs and salamanders to Frog Pond and Salamander Swamp. (
  • Their aim was to ensure that hundreds of amphibians would make it across the road unscathed during the annual spring migration, when frogs and salamanders that spend most of the year in the upland forest return en mass to the pond of their birth to mate and lay eggs. (
  • Amphibians and Reptiles - Lizards and frogs are high in protein and will be gobbled up by most birds, including peacocks. (
  • Even though they had the ability to evolve and survive for hundreds of millions of years - since before the time of the dinosaurs and through many climatic regimes - the massive, worldwide decline of amphibians can best be understood by their inability to keep pace with the current rate of global change, a new study suggests. (
  • Exposure to environmental pollutants such as polychlorinated biphenyls (PCBs) is now taken into account to partly explain the worldwide decline of amphibians. (
  • Concerning to the histological architecture of the seminiferous elements, to the amphibians and, in a general sense, the germ epithelium may be arranged in seminiferous locules in the Apoda ( Wake, 1969 ) and Anura ( Duellman & Trueb, 1994 ) or in seminiferous ampoules or testicular lobules the Urodela. (
  • Elevated levels of PKR after interferon induction sensitizes cells to react even more strongly to viral pathogens leading to a general inhibition of protein synthesis and potentially to apoptosis. (
  • The effect of estradiol-17ß and insulin on protein synthesis in primary monocultures of amphibian hepatocytes. (
  • Amphibians have been widely used to investigate the synthesis of biologically active steroids in the brain and the regulation of neurosteroid production by neurotransmitters and neuropeptides. (
  • Continuous protein synthesis is required for progesterone production and involves early events in the steroidogenic cascade prior to enzymatic conversion of pregnenolone to progesterone. (
  • Calmodulin (CaM) is a ubiquitous protein in nature and plays a regulatory role in numerous biological processes, including the upregulation of nitric oxide (NO) synthesis in vivo. (
  • The sperm nuclear bsic proteins (SBPs) in two anuran amphibians, Xenopus laevis and Bufo japonicus, were characterized, and their synthesis during spermatogenesis and removal during fertilization were studied. (
  • Publications] Yokota,T.,K.Takamune & Ch.Katagiri: 'Nuclear basic proteins of Xenopus laevils sperm;their characteriza-tion and synthesis during spermatogenesis. (
  • They also affect, at least at the highest concentration tested, the synthesis of proteins involved in normal cytogenesis (α-tropomyosin, myosin heavy chain, and α-actin). (
  • SR proteins are important in constitutive and alternative pre-mRNA splicing, mRNA export, genome stabilization, nonsense-mediated decay, and translation. (
  • SR proteins alternatively splice pre-mRNA by preferentially selecting different splice sites on the pre-mRNA strands to create multiple mRNA transcripts from one pre-mRNA transcript. (
  • Once splicing is complete the SR protein may or may not remain attached to help shuttle the mRNA strand out of the nucleus. (
  • As RNA Polymerase II is transcribing DNA into RNA, SR proteins attach to newly made pre-mRNA to prevent the pre-mRNA from binding to the coding DNA strand to increase genome stabilization. (
  • SR proteins can control the concentrations of specific mRNA that is successfully translated into protein by selecting for nonsense-mediated decay codons during alternative splicing. (
  • SR proteins can alternatively splice NMD codons into its own mRNA transcript to auto-regulate the concentration of SR proteins. (
  • Through the mTOR pathway and interactions with polyribosomes, SR proteins can increase translation of mRNA. (
  • Interchromatin granule clusters are for the storage and reassembly of pre-mRNA splicing proteins. (
  • The objective of the present study was to evaluate sheep IGS gland functional aspects and mRNA transcription and the protein expression of several hormone receptors, such as progesterone receptor (PGR), estrogen receptor 1 (ESR1), and 2 (ESR2) and prolactin receptor (PRLR) present. (
  • Such radicals acting on DNA could produce mutations, altering the transcrition into mRNA and the translation into proteins. (
  • There has been substantial progress in studies on non-protein-coding RNAs (ncRNAs) during the last decade. (
  • Smac, a mitochondrial protein that promotes cytochrome c-dependent caspase activation by eliminating IAP inhibition," Cell 102:33-42 (2000). (
  • In this study, we have identified by mass spectrometry two thermostable proteins, LEA (late embryogenesis abundant) and VTG (vitellogenin-like), found exclusively in the resting eggs of Brachionus manjavacas. (
  • Two-dimensional DIGE with a minimal labeling method coupled to nanoflow liquid chromatography-tandem mass spectrometry was used to detect and identify proteins differentially expressed under PCBs conditions. (
  • Here we show that uncleaved glycosylated SPF protein pheromones, secreted during courtship, are sufficient to elicit such behaviour in palmate newts (Lissotriton h. helveticus), indicating that these molecules obviate the need for copulation in these salamanders. (
  • Surprisingly, our finding of side-by-side secretion of Late Palaeozoic diverged proteins in a single species suggests that these molecules already had a courtship function in stem salamanders about 300 million years ago, rendering them one of the oldest vertebrate pheromone systems. (
  • These sugars appear to be tightly associated with specific heat soluble proteins (Walters et al. (
  • Finally, because many blood proteins are synthesized in the liver, we used thermal proteome profiling as an untargeted screen for soluble proteins that bind the alkaloid decahydroquinoline. (
  • The SBPs in Bufo consist exclusively of two protamines (Pl, P2), and those in Xenopus consist of 6 proteins (SPl-6) in addition to four nucleosomal core histones. (
  • The injected RNA contained a short sequence encoding an epitope derived from the human c-myc protein. (
  • Based on sequence analysis, SR proteins are suspected to be intrinsically disordered proteins resulting in an unstructured RS domain. (
  • In protein sequence and structure, anntoxin is very similar to dendrotoxins (the venoms found in cobras and other mamba snakes) and cone snail toxins. (
  • Complete amino acid sequence of human vitamin D-binding protein (group-specific component): evidence of a three-fold internal homology as in serum albumin and alpha-fetoprotein. (
  • For lentiviruses, a viral regulatory protein named Rev promotes the nuclear export of unspliced and incompletely spliced viral RNA by binding to its cognate RNA sequence, the Rev response element (RRE) ( 4 , 5 , 24 ). (
  • Cocoon Capers are high-protein, frozen Musca domestica fly pupae reared at our insectary in Catalina, AZ. (
  • Vets strongly suggest the dog food with less than 18 protein that takes care of the nutritional needs of the dog as well as protect them from the threats of consuming high protein foods. (
  • Objective Deficiency or reduced expression of signal transduction and activation of RNA family protein Quaking ( Qki ) is associated with developmental defects in neural and vascular tissues and the development of debilitating human diseases including colorectal cancer (CRC). (
  • Molecular cloning of bombinin-encoding cDNAs from skin found that bombinins and bombinin Hs were coencoded on the same precursor proteins. (
  • An understanding of these molecular recognition events provides insights into the underlying mechanism of the amphibian host-defense system. (
  • p26 is a heat shock protein and a proposed molecular chaperone. (
  • Artemin is a thermally stable RNA binding protein, and has also been implicated as a possible molecular chaperone (Sharon et al. (
  • 2004). Current research suggests that molecular chaperones prevent protein aggregation in encysted embryos during stressful environmental conditions (Sharon et al. (
  • High-molecular-weight Whiff proteins between 40 and 90 kDa were recognised by more than 80% of patients' sera. (
  • Here we show that this intercoelomocyte adhesion is mediated by amassin, a coelomic plasma protein with a relative molecular mass ( M r ) of 75 kD. (
  • Scientists at the Hamburg Outstation of the European Molecular Biology Laboratory (EMBL) and collaborators from King's College in London have now discovered that something similar happens to a protein that is crucial in the formation of muscle tissue. (
  • The RRM domain mediates the RNA interactions of the SR proteins by binding to exon splicing enhancer sequences. (
  • Nucleic acid sequences encoding such proteins and assays employing same are also disclosed. (
  • The large number of 3FTx protein sequences available, together with a growing database of RFS venom 3FTxs, make possible predictions concerning structure-function relationships among these toxins and the basis of selective toxicity of specific RFS venom 3FTxs. (
  • Protein NES are hydrophobic rich sequences that have a characteristic spacing of leucine, isoleucine, valine, and/or phenylalanine. (
  • RGD sequences have also been found to be responsible for the cell adhesive properties of a number of other proteins, including fibrinogen, victronectin, von Willebrand factor and many other glycoproteins. (
  • Recombinant human epidermal growth factor ( EGF , 2-10 ng/ml) stimulated growth and production of non-collagenous proteins, but inhibited production of collagen by 60% in cultured human skin fibroblasts. (
  • Proteomics has been initially used successfully in drug discovery, biomarker identification, and protein-protein interaction studies in human disease processes ( 23 , 24 ). (
  • Human RNA helicase A was recently identified to be a shuttle protein which interacts with the constitutive transport element (CTE) of type D retroviruses. (
  • Wilmanns' lab and the team of Mathias Gautel, an EMBL alumnus and now at King's College, have thought that a molecule called titin, the largest protein made by human cells, is involved. (
  • A number of serum transport proteins are known to be evolutionarily related, including albumin, alpha-fetoprotein, vitamin D-binding protein and afamin [ PMID: 2481749 , PMID: 2423133 , PMID: 7517938 ]. (
  • Here the motor proteins which move the pigments organelles are subject to different regulatory mechanisms, and there is no interaction between the different cytoskeleton networks", says Ökten. (
  • However, target proteins of linear ubiquitination, as well as their specific cellular functions, have largely remained elusive. (
  • With this technology at hand, it is now possible to identify target proteins modified by linear ubiquitin, and to detect the exact position within the protein where the linear chain is attached. (
  • This is the first observation that LEA proteins may play a role in thermostability and the first report of a VTG-like protein in the phylum Rotifera. (
  • In the vertebrate evolutionary tree, amphibians occupy an essential position as ancient tetrapods. (
  • Rear-fanged snake venoms are therefore of considerable research interest due to the evolutionary novelties they contain, providing insights into the evolution of snake venom proteins and potential predator-prey coevolution in a broader phylogenetic context. (
  • In amphibians reinitation of meiosis following gonadotropin stimulation is linked to intrafollicular production and action of progesterone. (
  • Amphibian gonadotropins (pituitary extracts) stimulate a rapid and progressive increase in intrafollicular levels of progesterone which precedes GVBD during in vitro culture. (
  • The smallest amphibian (and vertebrate) in the world is a frog from New Guinea ( Paedophryne amauensis ) with a length of just 7.7 mm (0.30 in). (
  • The scientists found out that the mouse adapter protein as well as the clawed frog adapter protein has a specific domain which enables the switching between the transport of actin and microtubules. (
  • In the study Dr Gillian Morrison introduced frog PouV proteins into m. (
  • To find out exactly what function PouV proteins perform in frog embryo. (
  • The key protein in humans, called Oct4, which governs the process of unlimited division of stem cells, has an equivalent in the African clawed frog, called PouV. (
  • In the study, Dr Gillian Morrison introduced frog PouV proteins into mouse embryonic stem cells lacking Oct4 and found that the frog proteins "rescued" the stem cells ?in other words, the cells recovered their ability to divide without limit. (
  • To find out exactly what function PouV proteins perform in frog embryos, Dr Morrison injected special compounds into very young e mbryos, to inactivate the native PouV proteins. (
  • It was very exciting, and humbling, to find that the proteins from such an ancient animal such as the frog can rescue the behaviour of 'modern' mouse embryonic stem cells. (
  • Amphibian Proteins" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (