Biocontrol efficacy of Trichoderma asperellum-enriched coconut fibre against Fusarium wilts of cherry tomato.

AIMS: Agro-based wastes were evaluated as a medium for mass micropropagule production and optimal efficacy of Trichoderma asperellum B1092 in controlling Fusarium oxysporum f. sp. lycopersici and promoting tomato growth. This study focused on biological control because pathogen persistence in the soil makes the disease difficult to control. METHODS AND RESULTS: Rice bran, biochar, empty fruit bunches, coconut fibres, compost, top soil and mixed soil were evaluated as media for mass multiplication of T. asperellum, which is effective in controlling plant pathogens. Yielding the most colony forming units (CFU) among the media, coconut fibre was deemed most suitable for promoting sporulation. After 120 days on the medium, T. asperellum B1902 produced 9·053 × 105  CFU per gram coconut fibre; oil palm empty fruit bunches was second highest (7·406 × 105  CFU per gram). In field tests of T. asperellum B1092 against F. oxysporum f. sp lycopersici (causing Fusarium wilt of cherry tomato), B1092 significantly promoted plant growth compared to the control. The efficacy of this formulation resulted in increased growth of roots and shoots tomato plants and total lycopene, sugar, K, N, Ca, P and Mg content after 120 days. CONCLUSIONS: Trichoderma asperellum B1092 showed great field potential for improving productivity and quality of tomatoes and in controlling Fusarium wilt of cherry tomato. SIGNIFICANCE AND IMPACT OF THE STUDY: This innovative approach using a cheap agro-waste to control the persistent soil-borne Fusarium pathogen of cherry tomato should increase soil survival rate of Trichoderma and has potential for upscaling in the field for other crops.

The short-acting anesthetic propofol produces biphasic effects-depression and withdrawal rebound overshoot-on some (but not all) limbic evoked potentials in the behaving rat.

Propofol, the relatively new, short-acting general anesthetic, markedly enhances the action of GABA at the GABAA receptor. To evaluate its effects on field potentials evoked in the dentate gyrus (DG) during the anesthetic and recovery periods, propofol was administered intraperitoneally to behaving rats bearing stimulating electrodes in the dorsal perforant path (DPP), where medial perforant path fibers predominate, and in the anterior piriform cortex (PC; i.e., olfactory cortex), and recording electrodes in the DG. Input from the PC reaches the DG via the lateral perforant path. Population slow waves (SWs) were evoked by paired-pulse stimulation of the PC at a 32 ms interstimulus interval (ISI) to produce paired-pulse facilitation in the awake animal. We had previously demonstrated that amplitude of SW2 (produced by the second stimulus) was greatly decreased by GABAergic drugs and increased by antiGABAergic convulsant agents. After administration of propofol, mean amplitude of SW2 decreased immediately and remained low for 30-60 min during propofol-induced sleep (as expected), then unexpectedly increased to about 1.5- to 2-fold above pretreatment levels at 2-4 h before gradually returning to pretreatment levels. In addition, the DPP was stimulated to produce either paired-pulse inhibition (20 ms ISI) or facilitation (32 ms ISI) of DG population spikes (PSs) in the awake animal. PS2 was much more inhibited during propofol-induced sleep, than during the pretreatment period, consistent with an expected marked increase in recurrent inhibition. An overshoot in PS2 amplitude was observed only occasionally during recovery, suggesting that withdrawal overshoot in amplitudes is more characteristic of PC-evoked DG SW2 potentials. The overshoot in SW2 amplitude during recovery may have been related to propofol's 'rapid on-rapid off' actions on the GABAA receptor, perhaps resulting in a phenomenon like the 'GABA withdrawal syndrome'. Such an effect, if true, may help explain the rare occurrence of seizures, especially during recovery, associated with its use clinically.

Responses to Indispensable Amino Acid Deficiency and Replenishment Recorded in the Anterior Piriform Cortex of the Behaving Rat.

The anterior piriform cortex (APC) may house the sensor for essential amino acid homeostasis in the brain. Several lines of evidence suggest that the APC is activated shortly after ingestion of an amino acid deficient diet. We examined the averaged evoked potentials elicited in the APC by stimulation of the lateral olfactory tract, in awake, behaving rats before and after feeding basal (BAS), threonine devoid (DEV), or corrected (COR) diets to determine directly whether the APC is activated after eating a DEV diet. When fed the DEV diet, the absolute values for the amplitude of the first negative wave differed by 36.8 ± 5.8% (P≤ 0.005) from that seen after eating the BAS diet. The latency to the second negative wave was altered by 17.2 ± 3.7% (P ≤ 0.02) compared with BAS. These results were seen by 3 h after introduction of the diet, and show that the APC is indeed activated after ingestion of a DEV diet. Also, the responses to COR returned to BAS levels by 3 h. This supports the hypothesis that the APC is important both for rejection of the DEV diet and for the recognition of the replenishment of the limiting amino acid by the COR diet.

Hyperglycemic and insulin release inhibitory effects of Rosmarinus officinalis.

The effects of the volatile oil extracted from the leaves of Rosmarinus officinalis on glucose and insulin levels were investigated in normal rabbits, after the administration of an intraperitoneal glucose tolerance test (GTT). Also, the effects of the volatile oil on fasting plasma glucose levels, were studied in alloxan diabetic rabbits. In normal rabbits, the intramuscular (i.m.) administration of the volatile oil (25 mg/kg) produced 20% (P < 0.05), 27% (P < 0.01) and 55% (P < 0.001) increases in plasma glucose levels, above those of control animals, at the 60, 90 and 120 min intervals, respectively, following the administration of the intraperitoneal (i.p.) glucose test. The same treatment also resulted in a 30% (P < 0.002) decrease in serum insulin level, in comparison with that of control rabbits at the 30 min interval. In alloxan diabetic rabbits, R. officinalis volatile oil increased fasting plasma glucose levels by 17% (P < 0.05) above those of untreated animals 6 h after its administration. These data suggest that the volatile oil of R. officinalis has hyperglycemic and insulin release inhibitory effects in the rabbit.

The effects of Ramadan fasting on certain biochemical parameters in normal subjects and in type II diabetic patients.

Fasting levels of cholesterol, triglycerides, uric acid, fructosamine and glycosylated hemoglobin were measured in normal and in Type II diabetic subjects before the beginning and at the end of the Muslim month of fasting (Ramadan). In normal subjects, there was a significant increase (P<0.01) in triglycerides and uric acid levels as a result of Ramadan fasting. In diabetic patients, triglyceride levels decreased significantly (P<0.05), while uric acid levels showed a significant increase (P<0.01) as a result of the same type of fasting. There were no significant differences in cholesterol, fructosamine and glycosylated hemoglobin levels before and after fasting in either group. These finding suggest that although this type of fasting is effective in causing considerable changes in certain blood biochemical parameters in normal and diabetic subjects, it has no effect on the glycemic control of either normal or Type II diabetic subjects.

Comparison of the effects of propofol and thiopental on the pattern of maximal electroshock seizures in the rat.

The anticonvulsant effects of propofol and thiopental (thiopentone) were determined by measuring the durations of the various phases of maximal electroshock seizures in the rat. Five min. after intraperitoneal administration of subanaesthetic (6.25, 12.5 and 25 mg/kg) and 50 mg/kg doses of propofol, the 2 highest doses abolished both tonic hindlimb extensor phases (full and partial extension) in all rats and decreased the duration of the total tonic phases of the seizure. Although the lowest dose produced no effect, the 12.5 mg/kg dose decreased the duration of both the full and partial tonic extensor phases and increased the duration of tonic flexion, showing that even this low dose had anticonvulsant activity. Subanesthetic doses of thiopental (5, 10 and 20 mg/kg) produced similar changes in the maximal electroshock seizures except that even the lowest dose also significantly decreased the duration of total extension and total tonus. Postseizure depression was prolonged only by the highest dose of propofol. Thus, even low doses of either propofol or thiopental, that produced only minimal behavioural effects, had marked anticonvulsant effects against electrically induced convulsions in the rat. No evidence of enhanced convulsant maximal electroshock seizures patterns was observed at any dose.

The anticonvulsant effects of propofol, diazepam, and thiopental, against picrotoxin-induced seizure in the rat.

The anticonvulsant effects of propofol administered intravenously against picrotoxin-induced seizure were studied and compared with those of diazepam and thiopental in the rat using picrotoxin-seizure threshold. Comparable doses of the three agents ranging between 1.25-20.0 mg/kg, produced dose-dependent increases in picrotoxin-threshold dose. At the lowest administered dose (1.25 mg/kg), there were no significant differences in picrotoxin-threshold dose among the three agents. Using 2.5 mg/kg dose, propofol and diazepam were equally effective and both were significantly more effective than thiopental in increasing picrotoxin-threshold dose. At higher doses of anticonvulsants (10.0 and 20.0 mg/kg), propofol was significantly more effective than both diazepam and thiopental. These results indicate that propofol is an effective anticonvulsant against picrotoxin-induced seizure, and this effect is significantly greater than diazepam and thiopental at doses producing clear sedative and behavioral effects.

The effect of propofol and thiopentone on pentylenetetrazol seizure threshold in the rat.

The protective effects of subanesthetic and anesthetic doses of propofol and thiopentone against pentylenetetrazol (PTZ)- induced seizures were studied in the rat. Intraperitoneal administration of propofol and thiopentone at doses producing comparable levels of sedation prior to intravenous infusion of PTZ, resulted in a marker and significant increase in PTZ seizure threshold. However, at all doses, the effects of propofol on PTZ convulsive threshold were more profound. These data suggest that propofol is an effective anticonvulsant and affords a greater degree of protection than thiopentone against PTZ-induced seizures in the rat.