Interconvertible Kinetic States of t-Butylbicycloorthobenzoate Binding Sites of the γ-Aminobutyric AcidA Ionophores

The kinetics of t-[³H]butylbicycloorthobenzoate (TBOB) binding to the convulsant sites of the γ-aminobutyric acid_A (GABA_A) receptor-ionophore complex were examined in synaptosomal membrane preparations of rat brain. On and off rates of TBOB binding were accelerated by 1 μM GABA and decelerated by 1 μM bicuculline methochloride, a GABA_A antagonist. The presence of GABA and bicuculline methochloride created rapid and slow phases of dissociation, respectively. The three groups of rate constants distinguished for the dissociation of 4 nM and 30 nM [³H]TBOB represent multiaffinity states of the convulsant sites depending on the presence of GABA or bicuculline methochloride. Apparent association rate constants do not obey the equation k_app=k_off±k_on [TBOB] without assuming interconvertibility of the kinetic states during binding. Avermectin B_1a (AVM B_1a), a chloride channel opening agent, accelerated the association and dissociation of TBOB and resulted in a biphasic effect on TBOB binding, i.e., enhancement at low concentrations (EC₅₀, 7.8 nM) followed by displacement at high concentrations (IC₅₀ 6.3 μM) of AVM B_1a. AVM B_1a resulted in similar biphasic effects on t- [³⁵S]butylbicyclophosphorothionate binding. DIDS, an isothiocyanatostilbene derivative with irreversible anion channel blocking effect, selectively inhibited basal [³H]TBOB binding (IC₅₀ 125 μM DIDS) leaving the enhancement by AVM B_1a unaffected.     

Actions of avermectin B1a on the γ-aminobutyric AcidA receptor and chloride channels in rat brain

The interaction of avermectin B_1a (AVM) with the γ-aminobutyric acid (GABA) receptor of rat brain was studied using radioactive ligand binding and tracer ion flux assays. Avermectin potentiated the binding of [³H]flunitrazepam and inhibited the binding of both [³H]muscimol and [³⁵S]t-butylbicyclo-phosphorothionate to the GABA_A receptor. Inhibition of muscimol binding by AVM suggested competitive displacement. Two kinds of ³⁶chloride (Cl) flux were studied. The ³⁶Cl efflux from preloaded microsacs was potentiated by AVM and was highly inhibited by the Cl-channel blocker 4,4′-diisothiocyano-2,2′-stilbenedisulfonic acid (DIDS). However, it was not potentiated by GABA nor was it sensitive to the convulsants picrotoxin or bicuculline. On the other hand, ³⁶Cl-influx measurement in a different microsac preparation of rat brain was very sensitive to GABA and other GABA-ergic drugs. Avermectin induced ³⁶Cl influx into these microsacs in a dose–dependent manner, but to only 35% of the maximal influx induced by GABA. The AVM-induced ³⁶Cl influx was totally blocked by bicuculline. It is suggested that AVM opens the GABA_A-receptor Cl channel by binding to the GABA recognition site and acting as a partial receptor agonist, and also opens a voltage–dependent Cl channel which is totally insensitive to GABA but is very sensitive to DIDS.     

Application of Polyelectrolyte Theory to the Study of the B-Z Transition in DNA (1)

Abstract

We have used the polyelectrolyte theory to study the ionic strength dependence of the B-Z equilibrium in DNA. A DNA molecule is molded as an infinitely long continuously charged cylinder of radius a with reduced linear charge density q. The parameters a and q for the B and Z forms were taken from X-ray data: a _B = 1nm, q _B = 4.2, a _z = 0.9 nm and q _z = 3.9. A simple theory shows that at low ionic strengths (when Debye screening length r _D>>a) the electrostatic free energy difference F ^el _Bz = F ^el _Z - F ^el _B increases with increasing ionic strength since q _B>q_z. At high ionic strengths (when r _D<<a) the F ^el _BZ would go on growing with increasing ionic strength if the inequality q _B/^a _B<q_z/a _z were valid. In the converse case when q _z/q _B<a_z/a _B the F ^el _BZ value decreases with increasing salt concentration at high ionic strength. Since X-ray data correspond to the latter case, theory predicts that the F ^el _BZ value reaches a maximum at an intermediate ionic strength of about 0.1 M (where r _D～a). We also performed rigorous calculations based on the Poisson-Boltzmann equation. These calculations have confirmed the above criterion of nonmonotonous behaviour of the F ^el _BZ value as a function of ionic strength. Different theoretical predictions for the B-Z transition in linear and superhelical molecules are discussed. Theory predicts specifically that at a very low ionic strength the Z form may prove to be more stable than the B form. Thus, one can observe the Z-B-Z transition with increasing ionic strength. In the light of our theoretical findings we discuss numerous experimental data on the B-Z transition in linear and superhelical DNA.     

Effects of Nucleotides on [3H]Bradykinin Binding in Guinea Pig: Further Evidence for Multiple B2 Receptor Subtypes

Abstract: We have suggested recently the existence of three subtypes of B₂ bradykinin receptors in tissues of guinea pigs. We have classified these B₂ bradykinin receptors into B_2a, B_2b, and B_2c subtypes depending on their affinity for various bradykinin antagonists. Because the actions of bradykinin in different cell systems appear to be both dependent on and independent of G proteins, we sought to determine whether the binding of [³H]bradykinin to the B₂ subtypes is sensitive to guanine nucleotides and, therefore, possibly coupled to G proteins. In the ileum, where we have demonstrated B_2a and B_2b subtypes, specific [³H]bradykinin binding was reduced with GDP (100 μM) and the nonmetabolized analogue of GTP, guanyl-5′-yl-imidodiphosphate (GppNHp; 100 μM). Competition studies with bradykinin and with [Hyp³]-bradykinin, which shows approximately 20-fold greater selectivity for the B_2a subtype than bradykinin, were performed in the presence or absence of GppNHp (100 μM). The competition experiments demonstrated that binding to the B_2a subtype, which has higher affinity for [Hyp³]-bradykinin and bradykinin than the B_2b subtype, was lost in the presence of GppNHp, whereas binding to the B_2b subtype was unaffected. In contrast, GppNHp (100 μM) and GDP (100 μM) failed to alter specific [³H]bradykinin binding to B_2b and B_2c subtypes in lung. [³H]Bradykinin binding was unaffected by AMP, ADP, ATP, and GMP (100 μM each). Based on this evidence, we suggest that the B_2a bradykinin subtype is coupled to G proteins. The B_2b and B_2c subtypes are either not coupled to G proteins, or may be coupled to the G^o-type GTP binding proteins, which have been suggested to be less sensitive to guanine nucleotides. These data provide further evidence for three subtypes of B₂-type bradykinin receptors in guinea pig.     

Synthesis and antiproliferative evaluation of 6-aryl-11-iminoindeno[1,2-c]quinoline derivatives

A number of 6-aryl-11-iminoindeno[1,2-c]quinoline derivatives were synthesized and evaluated for their antiproliferative activities. Among them, (E)-6-{4-[3-(dimethylamino)propoxy]phenyl}-2-fluoro-9-hydroxy-11H-indeno[1,2-c]quinolin-11-one O-3-(dimethylamino)propyl oxime (23a) was the most active, exhibited GI₅₀ values of 0.64, 0.39, 0.55, 0.67, and 0.65 μM against the growth of Hep G2, Hep 3B, A549, H1299, and MDA-MB-231, respectively. Compound 23a inhibited the growth of hepatoma cell lines in a dose- and time-dependent manner. The proportion of cells was decreased in the G1 and accumulated in G2/M phase after 12 h treatment of 23a, while the hypodiploid (sub-G0/G1 phase) cells increased. Further investigations have shown that 23a induced cell cycle arrest at G2/M phase and induce apoptosis via activation of p53, Bax, and caspase-8 which consequently cause cell death.     

Capacity for sustained terrestrial locomotion in an insect: Energetics,thermal dependence,and kinematics

Summary The capacity for sustained, terrestrial locomotion in the cockroach. Blaberus discoidalis, was determined in relation to running speed, metabolic cost, aerobic capacity, and ambient temperature (T _a=15, 23, and 34°C; acclimation temperature=24°C). Steady-state thoracic temperature (T _tss) increased linearly with speed at each T _a.The difference between T _tss and T _awas similar at each experimental temperature with a maximum increase of 7°C. Steady-state oxygen consumption (VO_2ss) increased linearly with speed at each T _aand had a low thermal dependence (Q₁₀=1.0-1.4). The minimum cost of locomotion (the slope of the VO_2ss versus speed function) was independent of T _a.Cockroaches attained a maximal oxygen consumption (VO_2max). increased with T _afrom 2.1 ml O₂·g^-1·h^-1 at 15°C to 4.9 ml O₂·g^-1·h^-1 at 23°C, but showed no further increase at 34°C, VO_2max increased 23-fold over resting VO₂ at 23°C, 10-fold at 34°C, and 15-fold at 15°C. Endurance correlated with the speed at which VO_2max was attained (MAS, maximal aerobic speed). Temperature affected the kinematics of locomotion. compared to cockroaches running at the same speed, but higher temperatures (23–34°C), low temperature (15°C) increased protraction time, reduced stride frequency, and reduced stability by increasing body pitching. The thermal independence of the minimum cost of locomotion (C_min), the low thermal dependence of VO_2ss (i.e., y-intercept of the VO_2ss versus speed function), and a typical Q₁₀ of 2.0 for VO_2max combined to increase MAS and endurance in B. discoidalis when T _awas increased from 15 to 23°C. Exerciserelated endothermy enabled running cockroaches to attain a greater VO_2max, metabolic scope, and endurance capacity at 23°C than would be possible if T _tss remained equal to T _a. The MAS of B. discoidalis was similar to that of other arthropods that use trachea, but was 2-fold greater than ectotherms, such as salamanders, frogs, and crabs of a comparable body mass.Abbreviations T _a ambient temperature - T _t thoracic temperature - T _tss steady state thoracic temperature during exercise - T _trest thoracic temperature during rest - VO₂ oxygen consumption - VO_2rest oxygen consumption during rest - VO_2ss steady-state oxygen consumption during exercise - VO_2max maximal oxygen consumption; MAS maximum aerobic speed - C _min minimum cost of locomotion - t _end endurance time     

Production of aflatoxin byAspergillus parasiticus and its control

The aim of the present work was to investigate the production of aflatoxin byAspergillus parasiticus and to find out the possible ways to control it. Of 40 food samples collected from Abha region, Saudi Arabia, only 25% were contaminated with aflatoxins. Oil-rich commodities had the highly contaminated commodities by fungi and aflatoxins while spices were free from aflatoxins.Bacillus megatertum andB cereus were suitable for microbiological assay of aflatoxins. Czapek’s-Dox medium was found a suitable medium for isolation of fungi from food samples. The optimal pH for the growth ofA. parasiticus and its productivity of aflatoxin B₁ was found at 6.0, while the best incubation conditions were found at 30°C for 10 days. D-glucose was the best carbon source for fungal growth, as well as aflatoxin production. Corn steep liquor, yeast extract and peptone were the best nitrogen sources for both fungal growth and toxin production (NH₄)₂HPO₄ (1.55 gL^-1) and NaNO₂ (1.6 gL^-1) reduced fungal growth and toxin production with 37.7% and 85%, respectively. Of ten amino acids tested, asparagine was the best for aflatoxin B₁ production. Zn²⁺ and Co²⁺ supported significantly both fungal growth, as well as, aflatoxin B₁ production at the different tested concentrations. Zn²⁺ was effective when added toA. parasiticus growth medium at the first two days of the culture age. The other tested metal ions expressed variable effects depending on the type of ion and its concentration. Water activity (a_w) was an important factor controlling the growth ofA. parasiticus and toxin production. The minimum a_w for the fungal growth was 0.8 on both coffee beans and rice grains, while a_w of 0.70 caused complete inhibition for the growth and aflatoxin B₁ production. H₂O₂ is a potent inhibitor for growth ofA. parasiticus and its productivity of toxins. NaHCO₃ and C₆H₅COONa converted aflatoxin B₁ to water-soluble form which returned to aflatoxin B₁ by acidity. Black pepper, ciliated heath, cuminum and curcuma were the most inhibitory spices on toxin production. Glutathione, quinine, EDTA, sodium azide, indole acetic acid, 2,4-dichlorophenoxy acetic acid, phenol and catechol were inhibitory for both growth, as well as, aflatoxin B₁ production. Stearic acid supported the fungal growth and decreased the productivity of AFB₁ gradually. Lauric acid is the most suppressive fatty acid for both fungal growth and aflatoxin production, but oleic acid was the most potent supporter. Vitamin A supported the growth but inhibited aflatoxin B₁ production. Vitamins C and D₂ were also repressive particularly for aflatoxin production The present study included studying the activities of some enzymes in relation to aflatoxin production during 20-days ofA. parasiticus age in 2-days intervals. Glycolytic enzymes and pyruvate-generating enzymes seems to be linked with aflatoxin B₁ production. Also, pentose-phosphate pathway enzymes may provide NADPH for aflatoxin B₁ synthesis. The decreased activities of TCA cycle enzymes particularly from 4th day of growth up to 10th day were associated with the increase of aflatoxin B₁ production. All the tested enzymes as well as aflatoxin B₁ production were inhibited by either catechol or phenol.     

Effects of the nematicide oxamyl on life cycle stages of Globodera rostochiensis

Hatched second stage juveniles of Globodera rostochiensis were found to be more sensitive than either unhatched juveniles or adult males to low concentrations of oxamyl (EC₅₀ value for activity 0.5 μg oxamyl ml^-1). Development of juveniles in roots was significantly inhibited by 2.0 μg oxamyl ml^-1 probably due to impairment of normal feeding activity. The behavioural events necessary for orientation of juveniles towards roots for invasion and orientation of males towards females for fertilisation were found to be impaired by 0.5 and 1.0 μg oxamyl ml^-1 respectively. A comparison with previous work on Meloidogyne incognita showed G. rostochiensis juveniles to be more sensitive to oxamyl.     

Major histocompatibility (B) complex effects on acquired immunity to cecal coccidiosis

The influence of the major histocompatibility (B) complex on acquired immunity to the avian coccidium Eimeria tenella was studied in 217 F₄ segregants (B ² B ², B ² B ⁵, B ⁵ B ⁵) of a cross between inbred lines 6₁ (B ² B ²) and 15₁ (B ⁵ B ⁵) and segregating haplotype combinations of UNH105 (B ²³ B ²³ B ²³ B ²⁴, B ²⁴ B ²⁴), a noninbred line of New Hampshire chickens. Chickens were immunized at 6 weeks of age with 500 oocysts daily for 5 days, then challenged 14 days later with 10000 oocysts. Responses to infection were evaluated by cecal lesion scores, body weight gain, delayed wattle reaction (DWR), and spleen weight. The F₄ segregants of genotypes B ² B ⁵ and B ⁵ B ⁵ exhibited greater immunity to challenge than B ² B ² chickens. B ⁵ B ⁵ chickens showed a significantly greater DWR following immunization and larger spleens 6 days after the challenge than either of the other genotypes. However, both BIBS and B ⁵ B ⁵ chickens demonstrated significantly lower lesion scores than B ² B ² chickens. There were no significant differences in weight gain among these genotypes. Among 139 line UNH105 segregants, B ²³ B ²³ hosts had significantly lower lesion scores than B ²⁴ B ²⁴ chickens. No other differences in immune response among line UNH105 genotypes were detected.     

Influence of vitamin B12 and light on the formation of chlorosomes in green- and brown-colored Chlorobium species

The specific Bchl a and c content of the vitamin B₁₂-dependent Chlorobium limicola strain 1230 decreased strongly under vitamin B₁₂ limitation. In comparison to a regularly grown culture (20 g vitamin B₁₂/l) the specific Bchl c content of a B₁₂-limited culture was reduced to 20% and the specific Bchl a content to 42%. By ultrathin sections it could be clearly demonstrated that B₁₂-deficient cells contained no chlorosomes. After the addition of vitamin B₁₂ to a deficient culture, chlorosomes were formed and the Bchl a and c content increased again to the level of regularly grown cells. The brown-colored Chlorobium phaeobacteroides strain 2430 (type strain) and the extremely low-light-adapted strain MN1 were compared with respect to the influence of light on the formation of chlorosomes and the Bchl e and carotenoid content. By ultrathin sections it could be demonstrated that strain MN1 produced two-fold larger chlorosomes. Chlorosome dimensions of strain MN1 decreased with increasing light intensities. The number of chlorosomes per cell in both strains did not change with different light intensities. Strain MN1 formed twice as much Bchl e as the type strain when grown at 30 or below 1 mol · m^-2 · s^-1. Under comparable light conditions strain MN1 formed 14–57% more carotenoids than the type strain. Low light intensities aaused the carotenoid content to increase by 25% in strain 2430 in comparison to high light intensity.     

Synthesis and biological activity of brassinolide analogues, 26,27-bisnorbrassinolide and its 6-oxo analogue

Two hitherto unknown brassinolide analogues, (22R,23R)-2α,3α,22,23-tetrahydroxy-B-homo-7-oxa-24-nor-5α-cholestan-6-one (9b) and (22R,23R)-2α,3α,22,23-tetrahydroxy-24-nor-5α-cholestan-6-one (8a), were stereoselectively synthesized. In both the Raphanus and rice-lamina inclination tests, 9b exhibited almost the same activity as brassinolide (1) and 8a also showed ca 10–50% of the activity of 1.     

Water and water activity in the solid state fermentation of cassava starch by Aspergillus niger

Summary During the solid state fermentation (SSF) of cassava starch by Aspergillus niger estimations were made of total water, consumed water and the residual water remaining in small quantities after 23 h. A theoretical calculation based on the Ross equation showed that the water activity (a _w) of the substrate decreased to 0.85 towards the end of the culture. Such low values were assumed to be inhibitory to growth. The a _w of the substrate was increased when sugarcane bagasse was used as a high water retention capacity support. Higher growth rates and substrate conversion to biomass were obtained with this system, confirming that water availability is a critical factor in the SSF of starch substrates.Abbreviations A, B Experimental constants - a _w Water activity - H₂O_c Consumed water - H₂O_R Residual water - H₂O_T Total water - IDW Initial dry weight - IMC Initial moisture content - OUR Oxygen uptake rate - S Substrate dry weight - Sc Substrate conversion: consumed substrate/initial substrate - S _H Amount of sugars hydrolysed - SSF Solid state fermentation - X Biomass dry weight - W ^* Amount of solids/g of water     

Evidence for the possible involvement of the superoxide radicals in the photodegradation of bilirubin

The photodecomposition of bilirubin follows first order kinetics with ak _B value of 12.5 × 10^-3 min^-1. In the presence of a model system generating superoxide anions, such as xanthine-xanthine oxidase, thek _B value was 103 × 10^-3 min^-1 This ten-fold enhancement ofk _B value by xanthine-xanthine oxidase was abolished when the reaction mixture was supplemented with a superoxide ion scavenger— superoxide dismustase. Further, known singlet oxygen quenchers like Β-carotene and bistidine did not prevent the enhancement of bilirubin oxidation by xanthine-xanthine oxidase, thereby ruling out the obligatory conversion of Superoxide anion to singlet oxygen. It is concluded that radical oxygen mediated bilirubin degradation might be a natural catabolic route for the bile pigment degradation during oxygen stress. deceased May 1977.     

Structure and Conformation of 1-β-D-Ribo Furanosyl Pyridin-2-one-5-Carboxamide: An Anti-Inflammatory Agent

The pyrimidine nucleoside, 1-β-D-ribofuranosyl pyridine-2-one-5-carboxamide, is an anti inflammatory agent used in the treatment of adjuvant-induced arthritis. It is the 2-one isomer of 1-β-D-ribofuranosyl pyridine-4-one 5-carboxamide, an unusual nucleoside isolated from the urine of patients with chronic myelogenic leukemia and an important cancer marker. Crystals of 1-β-D-ribofuranosyl pyridine-2-one-5-carboxamide are monoclinic, space group C2, with the cell dimensions a = 31.7920(13), b = 4.6872 (3), c = 16.1838(11), β = 93.071(3)°, V = 2408.2(2) ų, D_calc = 1.496 mg/m³ and Z = 8 (two molecules in the asymmetric unit). The structure was obtained by the application of direct methods to diffractometric data and refined to a final R value of 0.050 for 1669 reflections with I ≥ 3σ. The nucleoside exhibits an anti conformation across the glycosidic bond (χ_CN = ?15.5°, ?18.9°), a C3 ′- endo C2 ′ -exo [³ ₂T] ribose pucker and g⁺ across the C(4 ′)-C(5 ′) exocyclic bond. The amino group of the carboxamide group is distal from the 2-one and lacks the intramolecular hydrogen bonding found in the related 2-one molecule. Nuclear magnetic resonance studies shows also an anti conformation across the glycosidic bond but the solution conformation of the furanose ring is not the same as that found in the solid state.     

Oxygen uptake rate regulation during cell growth phase for improving avermectin B<Subscript>1a</Subscript> batch fermentation on a pilot scale (2 m<Superscript>3</Superscript>)

Avermectin B_1a batch fermentation of Streptomyces avermitilis in a 2 m³ fermentor was investigated by oxygen uptake rate (OUR) regulation during cell growth phase. OUR was controlled by adjusting of aeration and agitation. Result showed that OUR strongly affected cell growth and antibiotics production. Avermectin B_1a biosynthesis could be effectively enhanced when OUR was stably regulated at an appropriate level in batch fermentation of S. avermitilis. Avermectin B_1a yield reached 5568 ± 111 mg/l by controlling maximal OUR between 15 and 20 mmol/l/h during cell growth phase, which was increased by 21.8% compared with the control (maximal OUR above 20 mmol/l/h). The stimulation effect on avermectin B_1a production could be attributed to the improved supply of propionic acid and acetic acid, the precursors of avermectin B_1a, in the cells. Hence, this OUR control method during cell growth phase may be a simple and applicable way to improve industrial production of avermectin.     

Polymorphism and Expression of cDNAs Encoding Glycinin Subunits

The nucleotide sequence of cDNA encoding the glycinin A₂B_1a subunit from var. Shirotsurunoko was determined and compared with that in the case of var. Bonminori. The comparison showed six nucleotide substitutions in the coding sequence, one of which results in one amino acid replacement, and three in the 3'-noncoding region. These differences indicate the occurrence of polymorphism of the glycinin A₂B_1a subunit gene between the cultivars. The present data together with the previous results indicating the polymorphism of the A_1aB_1b subunit gene [(Utsumi et al., J. Agric. Food Chem., 35, 210 (1987)] suggest that the polymorphism is a general property of glycinin subunit genes. The expression of cDNAs encoding the A₂B_1a and A_1aB_1b subunits was examined. The results obtained in both in vivo- and in vitro-expression experiments indicate that the resultant products were readily degraded.     

Suction volume and filtering efficiency of silver carp (Hypophthalmichthys molitrix Val.) and bighead carp (Aristichthys nobilis Rich.)

Experiments were conducted to measure the suction volume of silver carp and bighead carp of age 1 + with respiratory chamber, and to calculate the suction volume and the filtering efficiency with respect to changes in concentrations of food particles. Suction volume (B. ml/mouth) and filtering efficiency (E. %) were calculated using the following formula: C ₁=C₀(1-BE/v)ⁿ where C₀ and C₁ were the concentrations of specific food particles at the beginning and at the end of experiment, respectively, V was the volume (ml) of experimental water, and n was the total number of observation of suction made during the experimental period. The relationships between suction volume (ml/mouth) of age I+ silver carp (B_h) and bighead carp (B_a) and their standard lengths (L, cm) were: B _h=0.561L-8.94, B_a= 0.627L-7.48 while those of the fingerlings were: B _h= O.l70L-0.837, B_a= 0.157L-0.418. The suction volume of the fingerlings was mainly affected by fish size, the function of temperature between 15 and 25° C being negligible. However, temperature affected filtering rate (filtered volume per unit time) through its effect on filtering frequency. The filtering efficiency of the fishes for rotifers (Brachionus caliciflorus) was 100 per cent. The relationships between filtering efficiency and sizes of food particles smaller than or equal to that of a rotifer were: E _h=25.1 ln e.s.d. -13.6, E_a=22.2 In e.s.d. -33.1 where E_h and E_a were filtering efficiency of silver carp and bighead carp, respectively, and e.s.d. was the equivalent spherical diameter (μm) of food particles.     

(S)-1-(Pent-4′-enoyl)-4-(hydroxymethyl)-azetidin-2-one derivatives as inhibitors of human fatty acid amide hydrolase (hFAAH): synthesis,biological evaluation and molecular modelling

Abstract

A series of lipophilic ester derivatives (2a–g) of (S)-1-(pent-4′-enoyl)-4-(hydroxymethyl)-azetidin-2-one has been synthesised in three steps from (S)-4-(benzyloxycarbonyl)-azetidin-2-one and evaluated as novel, reversible, β-lactamic inhibitors of endocannabinoid-degrading enzymes (human fatty acid amide hydrolase (hFAAH) and monoacylglycerol lipase (hMAGL)). The compounds showed IC₅₀ values in the micromolar range and selectivity for hFAAH versus hMAGL. The unexpected 1000-fold decrease in activity of 2a comparatively to the known regioisomeric structure 1a (i.e. lipophilic chains placed on N₁ and C₃ positions of the β-lactam core) could be explained on the basis of docking studies into a revisited model of hFAAH active site, considering one or two water molecules in interaction with the catalytic triad.     

Genetics of gel consistency in rice (Oryza sativa L.)

Inheritance of gel consistency in rice was studied in crossés involving highamylose, low-gelatinizalion temperature parents with hard, medium, and soft gel consistency. The results of single-grain analysis of parents, F₁, F₂, B₁F₁, B₂F₂, and their reciprocal crosses from a single-season harvest showed that the differences between hard and soft, hard and medium, and medium and soft gel consistency are under monogenic control and that modifiers affect the expression of the trait. Multiple alleles at the same locus, hereby designated asgec ^a for medium gel consistency andgec ^b for soft gel consistency, were recessive to the wild type allele for hard gel consistency andgec ^a was dominant overgec ^b. The results indicate that selection for desired gel consistency can effectively be done in early segregating generations.     

Microwave accelerated solvent-free synthesis and antifungal evaluations of flavanones

Microwave irradiation of 2-hydroxy chalcones under solvent-free conditions resulted in a “green-chemistry” procedure for the preparation of flavanones in good yields, using an unmodified household microwave oven and silica as solid support. By irradiation of 2-hydroxy chalcones with trifluoroacetic acid over silica gel, 11 known flavanones were prepared in high yields. The synthesised compounds were characterised using spectroscopic techniques, namely, ¹H NMR, ¹³C NMR and IR, and screened for their antifungal activity in vitro against Sclerotium rolfsii and Rhizoctonia solani by poisoned food technique. The compounds tested were found to be more active against R. solani, whereas against S. rolfsii, moderate activity was observed, as evident from LC₅₀ values. The most potent compound 2-(4-fluorophenyl)-2,3-dihydrochromen-4-one (4a) had LC₅₀ value of 12.0 mg L^?1 followed by 11, 11a, 3a, 9a, 8a, 10a and 10 having LC₅₀ values 18.21, 18.3, 32.9, 50.7, 88.8, 118.8 and 119.7 mg L^?1, respectively.