Tulipa
Mollusk Venoms
Venoms from mollusks, including CONUS and OCTOPUS species. The venoms contain proteins, enzymes, choline derivatives, slow-reacting substances, and several characterized polypeptide toxins that affect the nervous system. Mollusk venoms include cephalotoxin, venerupin, maculotoxin, surugatoxin, conotoxins, and murexine.
Mutational analysis of amino acid residues involved in catalytic activity of a family 18 chitinase from tulip bulbs. (1/22)
We expressed chitinase-1 (TBC-1) from tulip bulbs (Tulipa bakeri) in E. coli cells and used site-directed mutagenesis to identify amino acid residues essential for catalytic activity. Mutations at Glu-125 and Trp-251 completely abolished enzyme activity, and activity decreased with mutations at Asp-123 and Trp-172 when glycolchitin was the substrate. Activity changed with the mutations of Trp-251 to one of several amino acids with side-chains of little hydrophobicity, suggesting that hydrophobic interaction of Trp-251 is important for the activity. Molecular dynamics (MD) simulation analysis with hevamine as the model compound showed that the distance between Asp-123 and Glu-125 was extended by mutation of Trp-251. Kinetic studies of Trp-251-mutated chitinases confirmed these various phenomena. The results suggested that Glu-125 and Trp-251 are essential for enzyme activity and that Trp-251 had a direct role in ligand binding. (+info)Purification, characterization, and sequencing of novel antimicrobial peptides, Tu-AMP 1 and Tu-AMP 2, from bulbs of tulip (Tulipa gesneriana L.). (2/22)
Novel antimicrobial peptides (AMP), designated Tu-AMP 1 and Tu-AMP 2, were purified from the bulbs of tulip (Tulipa gesneriana L.) by chitin affinity chromatography and reverse-phase high-performance liquid chromatography (HPLC). They bind to chitin in a reversible way. They were basic peptides having isoelectric points of over 12. Tu-AMP 1 and Tu-AMP 2 had molecular masses of 4,988 Da and 5,006 Da on MALDI-TOF MS analysis, and their extinction coefficients of 1% aqueous solutions at 280 nm were 3.3 and 3.4, respectively. Half of all amino acid residues of Tu-AMP 1 and Tu-AMP 2 were occupied by cysteine, arginine, lysine, and proline. The concentrations of peptides required for 50% inhibition (IC(50)) of the growth of plant pathogenic bacteria and fungi were 2 to 20 microg/ml. The structural characteristics of Tu-AMP 1 and Tu-AMP 2 indicated that they were novel thionin-like antimicrobial peptides, though Tu-AMP 2 was a heterodimer composes of two short peptides joined with disulfide bonds. (+info)Characterization of protein phosphatase 2A acting on phosphorylated plasma membrane aquaporin of tulip petals. (3/22)
A protein phosphatase holo-type enzyme (38, 65, and 75 kDa) preparation and a free catalytic subunit (38 kDa) purified from tulip petals were characterized as protein phosphatase 2A (PP2A) by immunological and biochemical approaches. The plasma membrane containing the putative plasma membrane aquaporin (PM-AQP) was prepared from tulip petals, phosphorylated in vitro, and used as the substrate for both of the purified PP2A preparations. Although both preparations dephosphorylated the phosphorylated PM-AQP at 20 degrees C, only the holo-type enzyme preparation acted at 5 degrees C on the phosphorylated PM-AQP with higher substrate specificity, suggesting that regulatory subunits are required for low temperature-dependent dephosphorylation of PM-AQP in tulip petals. (+info)Pesticide exposure in dwellings near bulb growing fields in The Netherlands: an explorative study. (4/22)
An explorative field study was conducted to assess residential exposure to pesticides, regularly applied in bulb farming. House dust floor samples were taken from homes of bulb farmers (n = 12) and from homes in close proximity to a bulb field (i.e. non-farmers) (n = 15). Samples were analysed for 7 pesticides used by bulb growers in the sampling period. Of these pesticides, chloropropham, flutolanil and vinchlozolin could be detected in non-farmers homes. All pesticides were detected in farmers' homes, except metamitron. Median concentrations for chloropropham were significantly higher in farmers' homes (0.05 vs. 0.20 microg/m(2), p = 0.03). Logistic regression analyses showed that the odds for detecting pesticides were higher in farmers' compared to non-farmers' homes and remained higher after correction for potential confounders. Results showed no significant effect of proximity of a residence to a bulb field for median concentrations of pesticides; however, logistic regression analysis showed a borderline statistically significant effect for detecting chloropropham above the detection limit (OR = 10, p = 0.08). These findings demonstrate that, as expected, risk of exposure is higher for bulb farmers than for non-farmers. They also indicate that exposure to pesticides is not limited to bulb farmers only, and this warrants further investigation. (+info)Purification and characterization of protein phosphatase 2A from petals of the tulip Tulipa gesnerina. (5/22)
The holoenzyme of protein phosphatase (PP) from tulip petals was purified by using hydrophobic interaction, anion exchange and microcystin affinity chromatography to analyze activity towards p-nitrophenyl phosphate (p-NPP). The catalytic subunit of PP was released from its endogenous regulatory subunits by ethanol precipitation and further purified. Both preparations were characterized by immunological and biochemical approaches to be PP2A. On SDS-PAGE, the final purified holoenzyme preparation showed three protein bands estimated at 38, 65, and 75 kDa while the free catalytic subunit preparation showed only the 38 kDa protein. In both preparations, the 38 kDa protein was identified immunologically as the catalytic subunit of PP2A by using a monoclonal antibody against the PP2A catalytic subunit. The final 623- and 748- fold purified holoenzyme and the free catalytic preparations, respectively, exhibited high sensitivity to inhibition by 1 nM okadaic acid when activity was measured with p-NPP. The holoenzyme displayed higher stimulation in the presence of ammonium sulfate than the free catalytic subunit did by protamine, thereby suggesting different enzymatic behaviors. (+info)Intracellular energy depletion triggers programmed cell death during petal senescence in tulip. (6/22)
(+info)Application of pressure probe and UV-MALDI-TOF MS for direct analysis of plant underivatized carbohydrates in subpicoliter single-cell cytoplasm extract. (7/22)
(+info)Floral iridescence, produced by diffractive optics, acts as a cue for animal pollinators. (8/22)
(+info)I'm sorry for any confusion, but "Tulipa" is not a medical term; it is the genus name for tulips, which are types of bulbous plants in the family Liliaceae.
"Tulipa" is not a medical term. It is the genus name for Tulips, which are a type of spring-flowering bulb in the family Liliaceae. They are native to Southern Europe and Central Asia, but have been cultivated all over the world for their beautiful flowers.
If you meant to ask about a different term, please let me know and I will be happy to help you find a definition.
'Mollusk venoms' refer to the toxic substances produced by certain species of mollusks, such as cone snails and blue-ringed octopuses, which they use primarily for hunting and defense purposes.
Mollusk venoms are toxic substances produced by certain species of mollusks, a group of marine animals that includes snails, slugs, clams, octopuses, and squids. These venoms are primarily used for defense against predators or for hunting prey. They can contain a variety of bioactive molecules, such as proteins, peptides, and neurotoxins, which can cause a range of effects on the victim's body, from mild irritation to paralysis and death.
One well-known example of a mollusk venom is that of the cone snail, which uses its venom to capture prey. The venom of some cone snails contains compounds called conotoxins, which are highly selective for specific ion channels in the nervous system and can cause paralysis or death in their victims. These conotoxins have been studied for their potential therapeutic applications, such as pain relief and treatment for neurological disorders.
It's important to note that while some mollusk venoms can be dangerous or even deadly to humans, most species of mollusks are not harmful to people. However, it's always a good idea to exercise caution when handling any marine animals, as even non-venomous species can cause injury with their sharp shells or other structures.