Fluorescence polarization as a tool to study lectin-sugar interaction

The binding ofRicinus communis agglutinin andAbrus agglutinin to 4-methylumbelliferyl β-D-galactopyranoside was studied by equilibrium dialysis, fluo-rescence quenching and fluorescence polarization. The number of binding sites and the association constant value obtained by fluorescence polarization for bothRicinus communis agglutinin andAbrus agglutinin are in close agreement with those obtained by the other methods. This indicates the potential of ligand-fluorescence polarization measurements in the investigation of lectin-sugar interactions.     

Effect of carbohydrates on the growth ofRhizoctonia solani Kühn

The growth OfRhizoctonia solani in different carbohydrates was studied. The rate of growth of the fungus was traced by taking the dry weights of mycelia obtained from the carbohydrate medium at regular intervals and shifts in the pH were recorded. Different carbohydrate sources had different effects on the growth of the organism. The exoenzymes from the organism were capable of cleaving carbohydrates irrespective of whether the fungus grew in them or not.     

The cytologist and bacterioses of the vaginal-ectocervical area. Clues, commas and confusion

To evaluate the role of the cytologist in the diagnosis of bacterial vaginosis, the predominant bacterial patterns seen in 157 Papanicolaou-stained cervical smears were assessed and classified as large bacillus, anaerobic or scanty. A large bacillus pattern was found in 73 smears (46%), an anaerobic pattern in 77 (49%) and scanty bacteria in 7 (5%). Comma-shaped (curved) bacilli were found in 34 smears. The prevalence of clue cells in smears with anaerobic patterns was 73%. Gardnerella vaginalis was cultured from 89% of the cases with anaerobic-type smears containing clue cells and from 88% of those with anaerobic-type smears lacking clue cells. Mobiluncus sp. was cultured from 83% of the cases with anaerobic-type smears showing curved bacilli and 14% of those with anaerobic-type smears lacking curved bacilli. Papanicolaou-stained smears were found to be more sensitive and more specific for identifying clue cells than were wet preparations. A positive association was found between a positive KOH "whiff" test and the presence of curved bacilli on the Papanicolaou-stained smear. The clinical significance of these findings is discussed.     

Comparative study of cathinone and amphetamine on brown adipose thermogenesis

The effect of cathinone and amphetamine on brown adipose tissue thermogenesis and its modification with propranolol and timolol has been studied in rats. Both cathinone and amphetamine produced significant dose dependent increases in intracapsular brown adipose tissue (IBAT) and rectal temperatures. Amphetamine was found to be three times more potent as compared to cathinone, on a dose basis. Pretreatment of animals with propranolol and timolol individually inhibited cathinone and amphetamine induced hyperthermia. These findings suggest the involvement of beta adrenergic receptors in cathinone and amphetamine induced thermogenesis.     

Sea snake (Microcephalophis gracilis) hemoglobin: Primary structure and relationships to other forms

The hemoglobin of the sea snakeMicrocephalophis gracilis was purified and the primary structure of the α and β chains determined. This is the first sea snake hemoglobin structure characterized, and apparently also the first complete structure of any snake hemoglobin (an α chain of a viper was known), allowing judgments of reptilian variants. Variations between the sea snake form and other reptilian forms are large (52–65 differences for the α chains), of similar order as those between the sea snake and avian (56–65 differences) or human (58 differences) forms. Functionally, 19 residues at α/β contact areas and 7 at heme contacts are exchanged in relation to the human α and β chains. Four positions of the sea snake hemoglobin contain residues thus far unique to this form. However, all replacements appear compatible with conserved overall functional properties.     

Oil palm (Elaeis guineensis) protoplasts: isolation, culture and microcallus formation

Procedures are deseribed for the efficient isolation of protoplasts from a variety of oil palm (Elaeis guineensis Jacq.) tissues. Various factors including donor source, composition of enzyme mixture and culture medium affected the yield and viability of the protoplasts Polyembryogenic cultures of oil palm were the most suitable starting material in terms of yield, viability and metabolic competence. Pectolyase Y-23 in association with cellulase and hemicellulase was required for the efficient release of protoplasts from the oil palm tissues. Limited cell division to form microcallus was observed at very low frequency (<0.01%) when glutathione and catalase were incorporated in the culture medium.Abbreviations 2,4-d dichlorophenoxyacetic acid - DTT dithiothreitol - MES 2[N-morpholino] ethanesulphonic acid - NAA 1-naphthalene acetic acid - PVP polyvinylpyrrolidone