Complement activity, serum protein, and hepatic changes in guinea pigs given sterigmatocystin or aflatoxin, alone or in combination

Effects of either sterigmatocystin or aflatoxin, alone or in combination, given orally to guinea pigs were studied. Sterigmatocystin and aflatoxin B1 given alone and in combination at 4.2 mg/day and 0.01 mg/day, respectively, markedly reduced body weight. Although changes in total serum protein were not marked in any of the guinea pigs in this study, sterigmatocystin given alone and aflatoxin given alone significantly ( less than 0.05) decreased alpha2-globulin. The combination of toxins significantly (P less than 0.01) increased albumin and significantly (P less than 0.01) decreased both alpha2- and beta-globulins. Sterigmatocystin depressed complement activity, although not significantly. However, the combination of sterimatocystin with 0.01 mg of aflatoxin B1/day (an amount that does not affect complement activity alone) significantly (P less than 0.01) reduced complement activity. Increased severity of lesions was not found in guinea pigs given aflatoxin at 0.01 mg of B1 equivalents/day in addition to the sterigmatocystin.     

Effect of clonidine, quipazine, and LY 53857 on the prolactin-suppressant action of bromocriptine in rats

The alpha 2-adrenergic agonist clonidine hydrochloride, the serotonin agonist quipazine maleate, and the serotonin (5-HT2) antagonist LY 53857 were tested alone and in various combinations for their capabilities to increase mean serum prolactin (MSP) concentrations in rats given the synthetic ergot alkaloid CB-154 (2-bromo-alpha-ergocriptine), a known prolactin suppressor. The LY 53857 and the combination of clonidine, quipazine, and LY 53857 significantly decreased MSP concentrations. Quipazine given alone (10 mg/kg of body weight) was best able to increase MSP concentration and has potential to antagonize prolactin-depressant effects of ergot alkaloids.     

The effect of oral oxidised copper wire on liver copper in farmed red deer

Twenty-two weaner red deer stags grazed on a marginally copper-deficient property were used to evaluate the effect on liver copper levels of log oxidised copper wire particles given orally. The deer were assigned to two groups on the basis of pre-trial liver copper levels, and grazed together for the duration of the trial from March to October. Liver biopsies were collected from treated and control deer on six occasions at monthly intervals and were analyzed for copper content. Mean liver copper in the treated group rose from pre-treatment levels of 101.8 micromol/kg to a peak of 849.6 micromol/kg two months after copper administration. Thereafter, levels fell steadily until six months after administration when they averaged 84.8 micromol/kg. The mean liver copper content of untreated deer rose from 102.7 micromol/kg at the commencement of the trial, peaked at 255.3 micromol/kg after two months, fell to 103 micromol/kg one month later and remained low thereafter. The liver copper content in treated deer was significantly higher than for control deer for the duration of the study (p<0.01 for months 14 and 6, p <0.05 for month 5). It is concluded that log oxidised copper wire particles acted to provide adequate liver copper stores for up to five months in deer grazed on a marginally copper-deficient property.     

Editorial

Abstract

The major pulse crops in India are gram, pigeon pea, black gram, green gram, lentil and peas. Gram, pigeon pea and pea are attacked by several diseases some of which cause considerable crop damage. Gram is affected mainly by wilt (Fusarium oxysporum f. sp.ciceri Matuo and Sato), blight (Mycosphaerella pinodes B. and Blox) and rust (Uromyces ciceris-arietinii (Grogn.) Jacz. &; Boy.). The main diseases of pigeon pea are wilt (Fusarium oxysporum f. sp.udum (Butler) Snyd. and Hans.), and sterility mosaic. Powdery mildew (Erysiphe polygoni DC) and rust (Uromyces vicia-fabae (Pers.) Schroet.) are the most important pea diseases. Some diseases of minor importance are described. Details are given of the symptoms, distribution and control of the diseases with particular reference to those of economic importance. Several minor diseases of lentil, green gram and black gram are included.     

Caspases 3 and 7: key mediators of mitochondrial events of apoptosis

The current model of apoptosis holds that upstream signals lead to activation of downstream effector caspases. We generated mice deficient in the two effectors, caspase 3 and caspase 7, which died immediately after birth with defects in cardiac development. Fibroblasts lacking both enzymes were highly resistant to both mitochondrial and death receptor-mediated apoptosis, displayed preservation of mitochondrial membrane potential, and had defective nuclear translocation of apoptosis-inducing factor (AIF). Furthermore, the early apoptotic events of Bax translocation and cytochrome c release were also delayed. We conclude that caspases 3 and 7 are critical mediators of mitochondrial events of apoptosis.     

Effectiveness of palm and simulated geotextiles in reducing run-off and inter-rill erosion on medium and steep slopes

Palm‐leaf geotextiles could be an effective and cheap soil conservation method with enormous global potential. However, there are very few data on the effectiveness of palm geotextiles in reducing soil erosion by water. This study investigates the effectiveness of two types of palm geotextiles and the effect of geotextile mesh size on infiltration, run‐off and inter‐rill erosion rate and soil surface roughness on a medium and steep slope. A well‐defined protocol was developed to conduct laboratory experiments. Rainfall was simulated for 90 min with an intensity (I) of 45 and 67 mm h^?1 on an inter‐rill erosion plot, filled with an erodible sandy loam and having slope gradients (S) of 15 and 45%. Two palm‐leaf geotextiles (Borassus aethiopum and Brazilian Buriti Palm) and three simulated geotextiles (polyethylene tarpaulin) with different mesh sizes (1 × 1, 5 × 5 and 12 × 12 cm) were tested on a simulated fine tilth. Calculated k values from the Horton infiltration equation ranged from 0.025 to 0.145 and decreased linearly on both slopes with geotextile cover. Geotextiles are more effective in reducing the run‐off coefficient on a medium slope (15%) compared with that on a steep slope (45%), ranging from 76.4 to 17.9%. Mean b values from the mulch cover equation equalled 0.024 for a 15% slope and 0.045 for a 45% slope, indicating a higher effectiveness of geotextiles in reducing total inter‐rill soil loss on gentler slopes compared with commonly used mulches. Erosion‐induced soil surface roughness at the end of each experiment increased linearly with geotextile cover percentage and this increase was not significantly different between the two slope gradients.     

Plant community composition affects the biomass, activity and diversity of microorganisms in limestone grassland soil

The diversity and functional type of plants can affect the microbial biomass in the soil, its respiratory activity and the diversity of its bacterial population. We have studied these effects in microcosms of reconstituted limestone grassland containing (i) a 12‐species mixture of graminoids and forbs, (ii) a monoculture of the sedge Carex flacca, (iii) a monoculture of the grass Festuca ovina, and (iv) similar soil without plants. Microbial biomass was significantly greater in soil under monocultures of F. ovina than in the other microcosms. Basal respiration was largest in the F. ovina and mixed‐species treatments where values were more than double those in the C. flacca and bare soil microcosms. The basal respiration was strongly linearly related to plant productivity (r = 0.89). Analysis of the active bacterial population by denaturing gradient gel electrophoresis of 16S rRNA revealed its diversity to be significantly greater in the C. flacca and bare soil treatments than in the F. ovina or mixed‐species microcosms. This suggests that the functional type of plants has a strong influence on the composition of the bacterial community. We hypothesize that the discriminating functional attribute leading to a reduction of bacterial diversity in these microcosms was the presence in the F. ovina and mixed‐plant communities of an active arbuscular–mycorrhizal mycelium that is absent from bare soil and monocultures of C. flacca.     

An overview of lake neutralization experiments in Ontario

In 1981, an experimental neutralization program was initiated in Ontario to investigate the feasibility of using neutralization as an interim measure for the protection of acid-sensitive lakes and the restoration of acidified lakes. Aerial applications of powdered limestone (CaC0₃) to two lakes were used to increase whole-lake pH and alkalinity, and experiments were initiated to investigate the neutralization of lake trout (Salvelinus namaycush) spawning shoals with crushed limestone. Intensive studies are continuing to assess temporal patterns in water chemistry and to evaluate the long-term responses of zooplankton, phytoplankton, zoobenthos and fish communities.