Ovicidal and Deleterious Effects of Cashew (Anacardium occidentale) Nut Shell Oil and Its Fractions on Musca domestica,Chrysomya megacephala,Anticarsia gemmatalis and Spodoptera frugiperda

In this work, we evaluated the ovicidal activity and the deleterious effects of cashew (Anacardium occidentale) nut shell oil and its fractions on the development of Musca domestica and Chrysomya megacephala, important vectors of several diseases. The insecticidal effects of this plant were also measured on the first and second instar larvae of Anticarsia gemmatalis and Spodoptera frugiperda, soy and maize pests, respectively. The fly eggs and the crop pest insect larvae were exposed to the cashew (Anacardium occidentale) nut shell liquid (CNSL) and its fractions: technical CNSL, anacardic acid, cardanol and cardol. The results show that the cardol fraction, for both species of flies, presented the lowest lethal concentration with LC₅₀ of 80.4 mg/L for M. domestica and 90.2 mg/L for C. megacephala. For the mortality of the larvae of A. gemmatalis and S. frugiperda, the most effective fraction was anacardic acid with LC₅₀ of 295.1 mg/L and 318.4 mg/L, respectively. In all species, the mortality rate of the commercial compounds (cypermethrin 600 mg/L and temephos 2 mg/L) was higher than that of the evaluated compounds. Despite this, the results obtained suggest their potential in field trials, once the fractions of A. occidentale presented high mortality at low lethal concentrations in laboratory conditions, with the possibility of integrated use in the control of disease vectors and agricultural pests, employing ecofriendly compounds.     

Effect of auxin on cell wall glycanhydrolytic enzymes in epicotyls of Cicer arietinum

Cell wall glycanhydrolytic enzymes have been related to cell wall loosening and cell growth, although the mechanism of this relationship has not been clarified. Since auxins are plant hormones that stimulate growth in elongating organs, in the present work we studied the effect of auxin on cell wall glycanhydrolytic enzymes, which were extracted with LiCl. Our results show that incubation of sections of Cicer arietinum epicotyls with indoleacetic acid elicit some minor changes in electrophoretic patterns of cell wall proteins when compared with control sections. This indicates that there is no appearance of a specific polypeptide synthesized de novo in response to the hormone, although there are increases in the intensity of some of the polypeptides, which could indicate an enhancement of wall protein biosynthesis. Brief incubation with IAA led to a general increase in the specific activities of these different cell wall enzyme fractions separated by chromatography, with the exception of the α-fraction, with α-galactosidase activity. Longer incubation resulted in an increase in the amount of protein associated with some of the enzyme fractions. In particular, it induced a large increase in the amount of protein associated with the β111-galactosidase fraction that is involved in the autolytic process of cell walls of chick-pea epicotyls. Our results indicate that auxin-enhanced growth could be the result of the action of the hormone al the level of the cell wall glycanhydrolytic proteins that have been related to the wall-loosening process.     

Do invading leucocytes contribute to the decrease in glutathione concentrations indicating oxidative stress in exercised muscle, or are they important for its recovery?

Mice were subjected to one session of strenuous running exercise and their soleus muscles were examined in respect of changes in ultrastructure and to their concentration of reduced glutathione [GSH] which are indicators of oxidative stress. It was hypothesized that invading leucocytes contributed to oxidative stress and they were functionally inhibited in one experimental group by the administration of colchicine. Exercise led to an immediate decrease in [GSH] of about 60%, which slowly recovered during 96 h after exercise. With the administration of colchicine after exercise, [GSH] was higher than in the untreated exercise group 48 h after exercise, indicating an inhibition of the ability of leucocytes to produce oxidative stress. However, at 96 h after exercise, [GSH] was lower in the treated exercise group than in the untreated group. The morphological evaluation of the percentage of affected fibres showed that the invasion of leucocytes increased muscle fibre damage. The results suggested that invading leucocytes enhanced production of reactive species of oxygen that may have participated in inducing muscle damage. However, inhibition of leucocyte invasion did not permit their scavenger action of removing cell debris, which appeared to produce even more oxidative stress in the muscle.     

Esterase activity assay by flow injection analysis (FIA)

An automatic flow injection analysis (FIA) system for on-line determination of esterase activity has been developed. It is based on a colorimetric method using p-nitrophenyl propionate as substrate. The system permits a linear range analysis up to 0.18 U ml^–1, although the range can be extended up to 1 U ml^–1 without external dilution of the sample. The sampling frequency is of 4 samples per h with a relative standard deviation of 0.9%.     

Simultaneous on line monitoring of intracellular β-galactosidase activity and biomass using flow injection analysis inEscherichia coli batch fermentations

Summary A novel method to monitor on-line intracellular β-galactosidase activity and biomass simultaneously, using flow injection analysis (FIA), has been developed. The automatic ultrasonic cell disruption and FIA analysis allow the processing of 10 samples/hour with a wide and variable linear working range of β-galactosidase activity and biomass and a maximum relative standard deviation (RSD) of 1.5%. The system has been optimized by monitoring biomass and intracellular β-galactosidase activity inEscherichia coli batch fermentation.     

Comparison of the accumulation of astaxanthin in Haematococcus pluvialis and other green microalgae under N-starvation and high light conditions

Haematococcus pluvialis gave the highest astaxanthin accumulation rate (2.7 mg l^–1 day^–1) and total astaxanthin content ( 22.7 mg g^–1 biomass). Astaxanthin accumulation in Neochloris wimmeri, Protosiphon botryoides, Scotiellopsis oocystiformis, Chorella zofingiensis and Scenedesmus vacuolatus was, respectively, 19.2, 14.3, 10.9, 6.8 and 2.7 mg astaxanthin g^–1 biomass, respectively.     

Genetic variation in wild and cultivated populations of the haploid-diploid red alga Gracilaria chilensis: how farming practices favor asexual reproduction and heterozygosity.

The extent of changes in genetic diversity and life-history traits associated with farming was investigated in the haploid-diploid red alga, Gracilaria chilensis, cultivated in Chile. This alga belongs to one of the most frequently cultivated seaweed genera around the world. Fifteen farmed populations, 11 wild populations, and two subspontaneous populations were sampled along the Chilean coast. The frequency of reproductive versus vegetative individuals and of haploid versus diploid individuals was checked in each population. In addition, the distribution of genetic variation in wild and cultivated populations was analyzed using six microsatellite markers. Our results first demonstrated that farmed populations are maintained almost exclusively by vegetative propagation. Moreover, the predominance of diploid individuals in farms showed that farming practices had significantly modified life-history traits as compared to wild populations. Second, the expected reduction in genetic diversity due to a cultivation bottleneck and subsequent clonal propagation was detected in farms. Finally, our study suggested that cultural practices in the southern part of the country contributed to the spread of selected genotypes at a local scale. Altogether, these results document for the first time that involuntary selection could operate during the first step of domestication in a marine plant.