Antimicrobial effects of tea-tree oil and its major components on Staphylococcus aureus, Staph. epidermidis and Propionibacterium acnes

Major components of two tea-tree oil samples were identified using thin layer and gas-liquid chromatography (TLC and GLC). Using a TLC-bioautographic technique, the tea-tree oils, terpinen-4-ol, oc-terpineol and α-pinene were found to be active against Staphylococcus aureus, Staph. epidermidis and Propionibacterium acnes whereas cineole was inactive against these organisms. The MIC values of the three active compounds increased in the order α-terpineol < terpinen-4-ol < α-pinene for all three micro-organisms. MIC values of the tea-tree oils and terpinen-4-ol were lower for P. acnes than for the two staphylococci. This study supports the use of tea-tree oil in the treatment of acne, and demonstrates that terpinen-4-ol is not the sole active constituent of the oil.     

Identification and patterns of synapsis of the autosomally translocated Y-chromosome of the Indian mongoose,Herpestes auropunctatus (Hodgson)

The multiple sex chromosome system, X₁X₂Y /X₁X₁X₂X₂, in the small Indian mongoose, Herpestes auropunctatus, results from a translocation of a part of Y chromosome to an autosome. It is not possible to distinguish the autosome which harbours the Y chromosome element in the somatic complement. By employing the surface-spreading technique to prophase I meiocytes we have identified the region to which the Y chromosome has been translocated as the short arm of chromosome 9 which is a subtelocentric chromosome. This Y chromosome component lacks heterochromatin and no sex vesicle is organised during meiotic prophase. This suggests to us that Y heterochromatin in mammals may be required for the production of a sex vesicle.We take great pleasure in dedicating this paper to our revered teacher Prof. S.P. Ray-Chaudhuri, who initiated us to the field of Cytogenetics, on the occasion of his 75th birth day     

Measurement of Net Fluxes of Ammonium and Nitrate at the Surface of Barley Roots Using Ion-Selective Microelectrodes : II. Patterns of Uptake Along the Root Axis and Evaluation of the Microelectrode Flux Estimation Technique

Net fluxes of NH₄⁺ and NO₃⁻ into roots of 7-day-old barley (Hordeum vulgare L. cv Prato) seedlings varied both with position along the root axis and with time. These variations were not consistent between replicate plants; different roots showed unique temporal and spatial patterns of uptake. Axial scans of NH₄⁺ and NO₃⁻ net fluxes were conducted along the apical 7 centimeters of seminal roots of intact barley seedlings in solution culture using ion-selective microelectrodes in the unstirred layer immediately external to the root surface. Theoretically derived relationships between uptake and concentration gradients, combined with experimental observations of the conditions existing in our experimental system, permitted evaluation of the contribution of bulk water flow to ion movement in the unstirred layer, as well as a measure of the spatial resolution of the microelectrode flux estimation technique. Finally, a method was adopted to assess the accuracy of this technique.     

Hydrophobic surfaces in oligosaccharides: linear dextrins are amphiphilic chains.

Polysaccharide chains are usually considered to be highly hydrophilic, since they have no obvious nonpolar moieties in them. Yet, it is possible to realise conformations in these chains wherein all the hydroxy groups are disposed in one side or face of the chain and the hydrogens disposed in the other. We experimentally demonstrate that such an amphiphilic surface is present in linear oligomeric dextrins, i.e., alpha-1,4-linked D-glucosides, but not in alpha-1,6-D-glucosides (dextrans) or in beta-1,4-D-glucosides (cellulose). This amphiphilicity is generated as a consequence of the stereochemical constraints, which vary with the structure of the sugar and with the type of linkage. Oligosaccharide chains that can adopt incipient helical structures might display amphiphilicity. This property might be relevant to intermolecular recognition on cell surfaces, lectin-sugar binding, antigen-antibody interactions and the like, and might be manifested more in heteromolecular recognition process than as homomolecular self-aggregation.     

New coumarins from the umbels of Seseli sibiricum

Three new coumarins, seselinal, sesibiricol and sibirinol, and 12 known coumarins have been isolated from the umbels of Seseli sibiricum. The new coumarins have been characterized as 5, 7-dimethoxy-8-(2-methyl-2-formylpropyl)-2H-1-benzopyran-2-one, 5-(3-methylbut-2-enyloxy)-7-methoxy-8-(2-hydroxy-3-methylbut-3-enyl)-2H-1-benzopyran-2-one and 5,7-dimethoxy-8-(2-hydroxy-3-methylbut-3-enyl)-2H-1-benzopyran-2-one,respectively. The known ones were identified as sesibiricin, isosibiricin, osthol, coumurrayin, sesebrin, sesebrinol, sibiricin, imperatorin, bergapten, xanthotoxin, isopimpinellin and mexoticin.     

DIFFERENTIAL SENSITIVITY OF “DOUBLE” AND “SINGLE” FLOWERS OF NIGELLA DAMASCENA (RANUNCULACEAE) TO EMASCULATION AND TO GA3

In Nigella damascena “double” flower is inherited as a single-gene recessive to “single” flower. Early emasculation of “double” flowers greatly inhibits gynoecium development and, to a lesser degree, development of sepals and bracts. No comparable inhibition of gynoecia was induced in “single” flowers though some sepal and bract inhibition was detected. A differential nutritional requirement for organ initiation on cultured flower apices was also detected. Apices of both varieties initiated stamens and carpels if kinetin was added to the basal medium. However, in the absence of kinetin, GA₃ was required for organ initiation in “doubles” but completely inhibited stamen initiation in “singles.” Both these differential effects are thought to reflect rather different patterns of gibberellin metabolism in the two genetic strains.     

Testicular phosphatase activity in rats treated with cyproterone acetate & flutamide

Cyproterone acetate (CPA) and flutamide (F), 2 antiandrogens were tested in the rat, to determine their effect on acid (ACP) and alkaline (ALP) phosphatase activity. 70 fertile male rats were injected with either CPA, F, or testosterone propionate (TP) at either 2.5 or 10 mg. TP was injected either alone or in combination with the others. Histological examinations of the testes were performed. Spermatogenesis was arrested and Leydig cells atrophied in animals treated with CPA or F. Histochemical examination revealed that CPA enhanced ALP and ACP in the testes while F decreased ALP and ACP. TP treatment in combination with either antiandrogens was unable to overcome their effect. The changes in the 2 phosphatases depending on which antiandrogen was injected suggests different modes of action.