Deltamethrin-Mediated Effects on Locomotion, Respiration, Feeding, and Histological Changes in the Midgut of Spodoptera frugiperda Caterpillars

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is the main pest of maize crops, and effective methods for pest management are needed. The insecticidal efficacy of deltamethrin was evaluated against S. frugiperda for toxicity, survival, locomotion, anti-feeding, and histological changes in the midgut. Concentration–mortality bioassays confirmed that deltamethrin (LC50 = 3.58 mg mL−1) is toxic to S. frugiperda caterpillars. The survival rate was 99.7% in caterpillars not exposed to deltamethrin, decreasing to 50.3% in caterpillars exposed to LC50, and 0.1% in caterpillars treated with LC90. Spodoptera frugiperda demonstrated reduced mobility on deltamethrin-treated surfaces. Deltamethrin promoted a low respiration rate of S. frugiperda for up to 3 h after insecticide exposure, displaying immobilization and inhibiting food consumption. Deltamethrin induces histological alterations (e.g., disorganization of the striated border, cytoplasm vacuolization, and cell fragmentation) in the midgut, damaging the digestive cells and peritrophic matrix, affecting digestion and nutrient absorption.

Morphological characteristics and cell viability of coffee plants calli

The aim of this research was to characterize and compare two types of calli from leaf explants of Coffea arabica (cultivar Catiguá). Cells of different types of callus were successfully characterized regarding viability and internal and external morphological characteristics. It was obtained two morphologically distinct types of callus: (i) yellow friable and (ii) transparent watery. The yellow friable calli showed higher cell viability and embryogenic characteristics. Scanning and transmission electron microscopy showed embryogenic characteristics in cells of the yellow friable calli evidenced by the presence of small and isodiametric cells, while transparent watery calli showed elongated cells and large cytoplasm vacuolization.

Ultrastructural response of cabbage outer leaf mesophyll cells (Brassica oleracea L.) to excess of nickel

Changes in the structure and in the ultrastructure of cabbage outer leaf mesophyll cells [<em>Brassica oleracea</em> L.] cv. Sława from Enkhouizen were examined by means of light and electron microscopy. The examined plants were grown on the basic Murashige and Skoog medium with addition of excesive concentrations of nickel (added as NiSO₄ x 7H₂O),i.e. Ni 5, Ni 10 and Ni 20 mg/dm³. In Ni 5 mg samples mainly adaptation changes to the conditions of stress were observed. These changes were manifested by the increase of cytoplasm content and by cytoplasm vacuolization, by the increase of nucleus and nucleous volume, nucleolus vacuolization, the increase of plasmalemma invaginations and of the amount of rough ER, by the central arrangement of smooth ER and of the thylakoids of chloroplasts; it was also shown by the growth of the number of mitochondria and of peroxisomes in the cell. In Ni 10 mg samples, apart from adaptation changes, such as the increase of the nucleus volume, increase of plasmalemma invaginations, cytoplasm and nucleolus vacuolization, degeneration changes were also observed. They concerned mainly the nucleus (the increasing amount of condensed chromatin), ER (swelling and fragmentation of rER and sER), mitochondrium (swelling and reduction of cristae), Golgi apparatus (disintegration and decay) and chloroplasts (changes of shape, swelling and reduction of thylakoids, disappearance of starch and presence of big plastoglobuli). In Ni 20 mg samples cell protoplasts were in different stages of degeneration and the cell organelles that were identifiable, were usually damaged.

TAXOL INDUCES CELL DEATH WITH CYTOPLASM VACUOLIZATION IN PARAPTOSIS-LIKE BUT NOT ONCOSIS FASHION IN ASTC-a-1 CELLS

Recently, we found that high concentration of taxol (70 μM) induced cell death with cytoplasm vacuolization, the typical characteristic of both paraptosis and oncosis, in human lung carcinoma (ASTC-a-1) cells. This report was designed to further determine the form of taxol-induced cell death with cytoplasm vacuolization. It is generally considered that the cytoplasm vacuolization in oncosis due to the swelling of endoplasmic reticulum (ER), mitochondria, lysosomes and nuclei occurs after the loss of mitochondrial membrane potential (ΔΨm). However, flow cytometry (FCM) analysis showed that taxol-induced cytoplasm vacuolization preceded the loss of ΔΨm. Moreover, taxol treatment did not induce the collapse of microtubule, the typical characteristic of oncosis. These data demonstrated that taxol-induced cell death with cytoplasm vacuolization is not oncosis. FCM analysis by Annexin V-FITC/PI apoptosis detection kit further demonstrated that taxol-induced cell death with cytoplasm vacuolization is not apoptosis. In conclusion, in combination with our recent in vitro and in vivo data, this report further demonstrates that high concentration of taxol induces cell death with cytoplasm vacuolization in paraptosis-like but not oncosis fashion.

Ultra-structural and histochemical analysis of channel catfish (Ictalurus punctatus) liver treated with fumonisin B1

The histopathological effects of fumonisin B1 (FB1) injected intraperitoneally (IP), was evaluated in catfish (Ictalurus punctatus). Fishes were divided into four Groups. Groups II, III and IV were treated IP with FB1 injections of 1; 5 and 10 mg/kg bw/day, respectively, during 21 days. At the 7th, 14th and 21st day, fishes were sacrificed. The livers were hystologicaly analysed by the light and transmission electronic microscopy. Livers from the 7th day showed organelles alterations, particularly in the granular endoplasmatic reticle, mitochondria, nucleus and nucleolus mediated by FB1 doses. The occurrence of processes involved in the necrosis and apoptosis was detected. At the highest FB1 dose,the livers presented an intense response with an accentuate tissue disorganization, absence of cell limits and intense cytoplasm vacuolization. The image analysis showed the occurrence of necrosis in some areas, characterized by fully broken or swollen cells. The apoptosis was observed as the cytoplasm contraction and the chromatin formed masses concentrated in the edge of the nucleus. There was strong evidence that the numerous hepatocytes in the liver from the fishes under the toxic dose of FBs were selectively removed by the apoptosis process.