Purification and characterization of tubulin from the catfishHeteropneustes fossilis

Tubulin was purified from the brain of the catfishHeteropneustes fossilis by cycles of temperature-dependent assembly and disassembly. Fish tubulin assembles into microtubules in the absence of high molecular weight microtubule associated proteins. Its subunits comigrate with goat brain α andβ tubulin subunits and is composed of 4 major α andβ tubulins each as analyzed by isoelectric focusing and two dimensional gel electrophoresis. Peptide mapping showed it to be very similar to goat brain tubulin. Polymerization of catfish brain tubulin occurs optimally between 18–37°C and the critical protein concentrations of assembly at 18°C and 37°C are the same, as opposed to mammalian brain tubulins.     

Metal ions-nucleobases interactions: preparation and crystal structures of trichloroadeninium zinc(ii)(form ii) and a similar zinc complex of arprinocid [6-amino-9-(2-chloro-6-fluorobenzyl)purine]

Two zinc complexes—trichloroadeninium zinc(II)(Form 11), C₅H₆N₅Cl₃Zn [structure(I)] and a similar complex of Arprinocid, (6-amino-9-(2-chloro-6-fluorobenzyl)purine], C₁₂H₁₀N₅FCl₄Zn [structure(II)]—have been prepared Structure(I) crystallizes in the space group P2₁/c with a = 8.223(1)Å, b = 6.755(1) Å, c = 18.698(3) Å, β = 96.10(2)°,and Z = 4. Structure(II) crystallizes in the space group P2₁/c with a = 8.209(2) Å, b = 6.421(8) Å, c = 31.794(8) Å, β = 90.76(2)°, and Z = 4. Both of these structures were solved by the heavy atom method using diffractometric data and refined to R = 0.028 [structure(I)] and 0.038 [structure(II)]. Zinc with a distorted tetrahedral coordination having three chlorines and N(7) as ligators, protonation of the adenine moiety at N(1), dissymmetry of exocyclic angles at N(7), and an interligand hydrogen bond (“indirect chelation”) involving one of the three chlorines, coordinated to zinc and a proton of the exocylic amino group are the striking features common to both structures. Similar types of indirect chelation as observed in the different complexes of purines have been discussed. The zinc ion deviates from the imidazole plane by 0.412 Å in structure(I) and 0.524 Å in Structure(II). The imidazol and pyrimidine planes fold about the C(4)-C(5) bond by 2.4° in strctur(I) and 3.8° in structure(II). In structure(I), inversion related molecules are paired through N(9)-H…N(3) hydrogen bonds. N-H…Cl hydrogen bonds and C(8)-H…Cl interactions have been observed in both structures.     

Lagerenyl acetate and lagerenol two tetracyclic triterpenoids with the cycloartane skeleton from Lagerstroemia lancasteri

Lagerenyl acetate and lagerenol two new tetracyclic triterpenoids with the cycloartane skeleton together with four other triterpenoids 2α-hydroxy- 3β-E-p-coumaryloxy-urs-12-en-28-oic acid (jacoumaric acid, isolated as its monoacetylmethylcarboxylate derivative), 2α-hydroxyursolic acid (isolated as its diacetate), germanicyl acetate and friedelin, and sitosterol were isolated from the leaves and twigs of Lagerstroemia lancasteri. The structures of lagerenyl acetate and lagerenol were established as 3β-acetoxycycloart-24-one and 3β-hydroxycycloart-24-one, respectively, on the basis of spectral and chemical evidence.     

Occurrence of melittoside in the seeds of Plantago media

The ¹³C NMR and 360 MHz ¹H NMR signals of melittoside and its acetate have been assigned.     

Isopsoralene and its Use in Karyotype Analysis

Root-tips and leaf tips of different plants were kept for 1-2 hr at 12-14° C in saturated aqueous isopsoralene solution and stained in a mixture of 1 N HCl and 2% acetoorcein (1:9 by volume) by heating for 3-4 sec over a flame. They were then squashed in 1% aceto-orcein under a cover glass, the excess being blotted and the cover sealed. Preparations could be kept for about 15 days. A good chromosome morphology was secured. Isopsoralene was found to be suitable in cases where other coumarin derivatives as well as paradichloro-benzene failed to yield suitable results.