Structural organization and phytochemical analysis of Pimenta dioica (L.) Merrill (Myrtaceae) leaves collected from Gois State, Brazil

Objective: To assess the antifungal activities of the extracts of leaves of Pimenta dioica against human pathogenic fungi and identify the class of phytochemical responsible for the biological activity.Methods: The shade dried, and powdered leaves of Pimenta dioica were subjected to polarity based solvent extraction by soaking. The extracts were dried in a rotary flash evaporator and subjected to antifungal activity assay against Candida albicans, Microsporum canis and M. gypseum, by disc diffusion method. Antifungal active petroleum ether extract was subjected to phytochemical analysis to identify the active compound. The extract was then subjected to Thin Layer Chromatography (TLC) and Bioautography, by agar overlay method. The fractions were collected by Preparative TLC method and subjected to antifungal activity assay by disc diffusion method. Further, the Libermann-Burchard test was conducted to detect the broad group of compounds responsible for the bioactivity.Results: Among the five extracts viz. petroleum ether, chloroform, ethyl acetate, methanol and aqueous, the petroleum ether extract showed significant antifungal activity against Microsporum canis (50 mm), Microsporum gypseum (60 mm) and Candida albicans (23 mm). Terpenoids, tannins and flavonoids were found to be the chief constituents of the petroleum ether extract. The TLC of the extract revealed 7 spots with the Rf values 0.37, 0.42, 0.45, 0.52, 0.59, 0.76, 0.96 with the solvent system of hexane and acetone (1:0.5). The bioautography assay revealed inhibitory activity in the spots at Rf values 0.52 and 0.59. These fractions obtained by preparative TLC also confirmed the same. The phytochemical analysis of the fractions on the TLC plate suggests that the compound is triterpene or steroid.Conclusion: The antifungal activity of Pimenta dioica and the bioactive phytochemical has been reported in the present study. Preliminary phytochemical analysis has indicated that the compounds are triterpenes or steroids. The results indicate that the active compounds are potential lead molecules for new antifungal drugs in the management of infectious fungi.

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Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081693 ◽

1978 ◽

Vol 36 (2) ◽

pp. 166-167 ◽

Cited By ~ 1

Author(s):

G. Stöffler ◽

R.W. Bald ◽

J. Dieckhoff ◽

H. Eckhard ◽

R. Lührmann ◽

...

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Ribosomal Proteins ◽

Structural Organization ◽

Three Dimensional ◽

Ribosomal Subunit ◽

Spatial Arrangement ◽

Small Subunit ◽

Antibody Binding ◽

Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

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Ribosome Structural Organization

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051670 ◽

1974 ◽

Vol 32 ◽

pp. 332-333

Author(s):

James A. Lake

Keyword(s):

Ribosomal Proteins ◽

Structural Organization ◽

Three Dimensional ◽

Small Subunit ◽

Structural Studies ◽

X Ray Diffraction ◽

Specific Antibodies ◽

X Ray ◽

E Coli ◽

Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

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Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053310 ◽

1982 ◽

Vol 40 ◽

pp. 118-119

Author(s):

U. Aebi ◽

P. Rew ◽

T.-T. Sun

Keyword(s):

Electron Microscopy ◽

Structural Organization ◽

Cell Types ◽

Structural Features ◽

Molecular Architecture ◽

The Past ◽

Keratin Filaments ◽

Different Types ◽

10 Nm Filaments ◽

Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

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