Journal of Basic and Applied Zoology最新文献

Histological techniques used to stain lipids in invertebrate histology are sometimes inefficient to demonstrate the presence of these elements in cells, once these methods leave a residual background, making the separation of lipid from the remaining cytoplasmic content difficult. The use of imidazole-osmium is common in transmission electron microscopy (TEM), and it has provided very accurate label of the lipid. Aiming to optimize histochemical analyses, this study proposes a lipid staining protocol using the imidazole-osmium technique, modified to allow the observation of lipids in histological sections under light microscopy. In this experiment, two concentrations of imidazole-osmium (1% and 2%) were applied in salivary glands sections from Rhipicephalus sanguineus sensu lato (s.l.) ticks. The results showed that both concentrations allow accurate detection of the lipid content in cells, in the endomembranes in general and in the plasma membrane as well. In addition, different staining intensities were observed here, varying according to the different feeding periods (2, 4 and 6 days), once the salivary glands undergo alterations in the secretory cycle. The cells submitted to the concentration of 2% imidazole-osmium displayed a greater variation in the lipid staining intensity when compared with those exposed to 1%, indicating that this methodology under conventional light microscopy can be pointed as an efficient alternative for the analysis of invertebrate cells and tissues, providing clearer and more specific results in comparison with other techniques.

The methomyl lannate is a carbamate pesticide, which is widely used and has known toxic effects on non-target organisms including land snails. This research investigated the acute and sublethal effects of lannate on land snail Eobania vermiculata. LD₅₀ value (102.32 μg snail⁻¹) of lannate was determined 48 h following topical application. Some biomarkers such as acetylcholinesterase (AChE), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) as well as micronuclei (MN) and bi-nucleated cells (BN) were detected following 14-d topical exposure to sublethal doses 5.53, 21.32 and 53.30 μg snail⁻¹. The results showed that AChE inhibition in the cerebral ganglia was higher than that in the foot muscle. With the exception of ALP, a significant induction in hemolymph enzymes was detected in the snails exposed to 21.32 and 53.30 μg snail⁻¹. Also, the results showed that (MN) frequencies of lannate treated snails were ∼3-, 4- and 6-fold that of the control in the snail exposed to 5.53, 21.32 and 53.30 μg snail⁻¹, respectively. The observed changes in these biomarkers may provide useful information regarding environmental conditions and risk assessments of terrestrial organisms.

The aim of the present study was to determine the impact of nematode parasites on the metal balance of the Koshar fish Epinephelus summana. A total of 102 fish were randomly collected from the Red Sea, Jeddah coast, during the period of March to September 2014. The element concentrations in the infected and non-infected fish were analyzed using flame atomic absorption spectrometry. Nematodes were collected and described from fish liver, intestine, stomach and gonads. The results showed that intestinal and stomach nematodes caused significant decreases in both magnesium and lead and insignificant decreases in iron and calcium compared to non-infected fish. There were significant increases in potassium and sodium and insignificant increases in zinc and copper in fish infected with intestinal and stomach nematodes. Most elements significantly decreased in fish infected with gonadal nematodes, with the exception of magnesium and lead, which insignificantly decreased in comparison to healthy fish. Adult nematode infection in marine fish is considered to be a biological indicator for heavy metal pollution, and its presence can minimize the bioaccumulation of heavy metals in fish tissue and organs.

The purpose of the current study was to measure the ecotoxicity of silver nanoparticles (AgNPs) on Aporrectodea caliginosa earthworm. No adult earthworm mortality was observed at any treatment during the sub-chronic exposure period (28 d). Biomass and cellulase levels reduced in a concentration-dependent manner in the exposed earthworms compared to those of the control. The hatched cocoons from the contaminated substrates were significantly (p < 0.05) fewer than that of the control substrate. This finding provided further support for the conclusion that AgNPs may affect cocoon hatchability. Cocoon hatchability could therefore be a more reliable endpoint at a specific concentration than cocoon production. A significant increase in DNA damage was revealed in the earthworms treated with AgNPs compared to the untreated ones. The results denoted the effectiveness of measuring cellulase activity, biomass, reproduction and DNA damage and reinforced the application of the present methods in nanoparticles pollution biomonitoring studies.

Octopus vulgaris is of great importance for humans as a food resource and in fishery. The present study gave the first new insight about the comparative histopathological and histochemical impacts of oral administration of a single dose (25 mg/kg) of the posterior salivary gland (PSG) and ink sac (IS) extracts of O. vulgaris in mice. Histopathologically, the changes in the liver of PSG and IS extracts administrated mice were lymphocyte aggregations, cytoplasmic vacuolar degeneration and enlargement and congestion of hepatic portal veins. The changes caused by the PSG extract were more than those of the IS extract. In the treated spleen, IS extract showed higher impacts more than the PSG extract and occurred as lymphocyte aggregations, red pulp infiltration, increase of megakaryocytes number and mild distortion in the follicle shape. PSG and IS extracts exerted similar impacts in the ileum which detected as villi hyperplasia, epithelial and lamina propria degeneration, epithelial detachment and lymphocytes infiltration. Histochemically, IS extract increased hepatic collagenous fibers more than PSG extract especially after 7 days of administration. Both extracts reduced the liver general carbohydrates and illeal mucopolysaccharide biosynthesis. PSG and IS extracts exerted significant elevation in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes. Hematological studies after PSG administration revealed a significant increase in leukocytic count, and platelets and a significant decrease in lymphocytes and granulocytes. However, IS extract caused a significant increase in platelets. The present data could introduce new information about the toxicity of these extracts especially in the countries which depend on O. vulgaris ink in their food.

The Louisiana red swamp crayfish, Procambarus clarkii, which was introduced into Egypt in the1980s, has since become widespread across the country. Burrowing behavior of P. clarkii, was investigated in irrigation canal of three different sites (Abou-Kabir, Abou-hammad and Belbies) at Sharkia Governorate from January 2014 to December 2015. Most burrows were simple in their morphology and few of them had two types of chimney (plugged and open). Open chimney was present at 100 cm of the edge side of irrigation canal, while plugged cap chimney was located inside the agriculture soil. Result indicated that a great number of P. clarkii were observed migrating across roadways to find the main irrigation canal, during their crossing many of them were killed by cars. The highest mean numbers of burrows and population density of P. clarkii were recorded at Abou-Kabir followed by Abou-hammad while Belbies was the lowest one in this respect during two successive years of 2014 and 2015. Furadan 10G is routinely applied in Egypt rice fields was examined in the laboratory against P. clarkii in trial to control its explosive populations in certain closed habitats. Data showed that after 96 h, at the higher concentrations (70 ppm) 100 and 90% of mortality were recorded for adult males and females of P. clarkii, respectively while at lower concentrations (50 ppm) the mortality was 70 and 60% for both sexes respectively. LC₅₀ of furadan was 58.26 and 63.60 ppm for adult males and females, respectively.

The red pumpkin beetle (RPB), Aulacophora foveicollis, becomes a notable thread to cucurbitaceous family. The present investigation studied the efficiency of Beauveria bassiana (B8) isolate against RPB. The results revealed that, they secured lowest lethal concentration (9 × 10³) besides stunning growth over treated adult RPB. The gradual increase and dispersal of hyphea from thoracic region of the insect to all over the body was studied clearly in the present investigation. From this study, it was strongly recommended that, the B. bassiana would be a promising biocontrol agent and suggested for the field RPB management.

We have attempted to identify the chromosomal region harboring genes encoding major glue fractions by correlating the glue protein synthesis with the puffing pattern of the X-chromosome of Drosophila nasuta nasuta during normal larval development and in the presence of exogenous 20-OH Ecdysone. The division 10 of the X-chromosome was characterized by the presence of a puff right from early third instar which attains its maximum size in the mid third instar stage and remains active till the onset of prepupal stage. The puff was found to regress when larvae/glands were exposed to exogenous 20-OH Ecdysone in vivo or in vitro, suggesting that it is an intermolt puff. Salivary glands treated with 20-OH Ecdysone revealed a significant reduction in the total protein content as well as X-linked glue fractions resolved by SDS–PAGE.

The insect cuticle is composed of various proteins and formed during the moult under a complex biological process that depends on the cross talk between hormone levels and gene expression. In the present study, we aimed to clarify the ecdysone-dependent temporal regulation mechanisms of cuticular proteins expression and the underlying control of Bombyx mori metamorphosis. The expression of CPR55 was observed from the W3 early stage and peaked at pupation when the ecdysteroid titre declined. CPR55 was induced by the ecdysone pulse, and their expression peaked at 24 h after transfer to a hormone free medium. Transcripts of CPR55 were neither observed after the 20E pulse treatment in the presence of cycloheximide nor after the addition of 20E in V4 wing discs. We analysed the upstream region of the CPR55 gene using a transient reporter assay with a gene gun system which identified only one βFTZ-F1 binding site important for cis-acting elements for the transcription activation of the luciferase reporter gene by an ecdysone pulse. Site-directed mutagenesis of this element in the context of the 589-bp promoter fragment drastically decreased the reporter activity. The nuclear protein bound to βFTZ-F1 sites was identified by an electrophoretic mobility shift assay suggesting that CPR55 expression was regulated by βFTZ-F1 through the ecdysone pulse. The results confirmed that transcription factor, BmβFTZ-F1, binds to the cis-regulatory elements in the promoter of the gene coding for cuticle protein, CPR55, and regulates its expression during B. mori metamorphosis.

The present study has been designed to determine the hemolymph protein changes induced by EBI using Microtron (ranges from 20 to 100 Gy) on the 5^th instar larvae of silkworm, Bombyx mori using SDS–PAGE. The EBI did not caused any impact on 5^th instar larval hemolymph proteins, however a significant reduction of pupal hemolymph proteins such as lipophorin (250 kDa), vitellogenin (180 kDa), storage protein (76–80 kDa) and a 30 kDa protein was observed through SDS–PAGE and densitometry analysis. These proteins are known to play a crucial role in various developmental processes including transport of lipids, as amino acid reservoir for providing precursors for egg and cuticle formation and immunity of B. mori. Further, a decrease of antioxidant enzymes such as Superoxide Dismutase (SOD) and Catalase (CAT) in the EBI treated larval and pupal hemolymph was observed. In addition, a negative influence on growth characteristics and appearance of pupal deformity was noted. This may be due to damage in hemolymph proteins, when the larvae were exposed to EBI at >80 Gy.