In this study, laboratory bioassays were performed to investigate the impact of sublethal concentrations of Cu (CuCl2: 1000, 100, 10 mg L−1), Pb (PbCl2: 10, 1, 0.1 mg L−1) and Cd (CdCl2: 0.1, 0.01, ...0.001 mg L−1) on honey bee redox status and the activity of the main antioxidative enzymes and their gene expression. Our results show that exposure to these metals led to significant changes of gene expression, the levels of enzyme activity and redox status, but the effects are metal and dose dependent. In general, exposure of 48 h to given concentrations of Cu, Cd and Pb did not change the activity of antioxidative enzymes and the level of lipid peroxidation, with the exception of decreased activity of catalase at the lowest concentration of cadmium. Only lead produced increases in glutathione and thiol groups. Expression of genes for catalase and superoxide dismutase changed with exposure to cadmium and copper, whilst lead induced only expression of superoxide dismutase genes. The results from this study provide basic data for future research regarding the impacts of metal pollution on Apis mellifera and will be an important step towards a comprehensive risk assessment of the environmental stressors on honey bees.
•Insights from laboratory experiments open the way for further field experiments.•Sublethal concentrations of Cu, Pb and Cd were applied.•Cu, Pb and Cd induced gene expression of antioxidant genes in dose dependent manner.•The lowest concentration of cadmium decreased activity of catalase.•Lead induced increases in glutathione and thiol groups.
In the present study, the influence of cadmium, copper, and lead on two enzymes often used as biomarkers in toxicological analysis was investigated. Bees were fed with 1 M sucrose solution containing ...10-fold serial dilutions of CuCl
2
(1000 mg L
−1
, 100 mg L
−1
, and 10 mg L
−1
), CdCl
2
(0.1 mg L
−1
, 0.01 mg L
−1
, and 0.001 mg L
−1
), or PbCl
2
(10 mg L
−1
, 1 mg L
−1
, and 0.1 mg L
−1
) during 48 h. Our results showed that the total glutathione
S-
transferase activity was not changed under the influence of cadmium and lead, and it was decreased with the highest concentration of copper. The level of gene expression of the three analyzed classes of glutathione
S-
transferase was significantly increased with increasing concentrations of copper and cadmium. Lead did not cause significant changes in glutathione
S-
transferase activity and gene expression, while it showed biphasic effect on acetylcholinesterase activity: lower concentration of lead, 0.1 mg L
−1
inhibited and higher dose, 10 mg L
−1
induced acetylcholinesterase activity in honey bees. Furthermore, our results showed a significant decrease of the acetylcholinesterase activity in honey bees treated with 0.001 and 0.01 mg L
−1
CdCl
2
. Our results indicate the influence of cadmium, copper, and lead on GST and AChE in the honey bees. These results form the basis for future research on the impact of metallic trace element pollution on honey bees.
Metallothioneins are ubiquitous proteins important in metal homeostasis and detoxification. However, they have not previously been identified in honey bees or other Hymenoptera, where ...metallothioneins could be of ecophysiological and ecotoxicological significance. Better understanding of the molecular responses to stress induced by toxic metals could contribute to honey bee conservation. In addition, honey bee metallothionein could represent a biomarker for monitoring environmental quality. Here we identify and characterize a metallothionein gene in Apis mellifera (AmMT). AmMT is 1,680 bp long and encodes a 48 amino acids protein with 15 cysteines and no aromatic residues. A metal response element upstream of the start codon, coupled with numerous cis‐regulatory elements indicate the functional context of AmMT. Molecular modelling predicts several transition metal binding sites, and comparative phylogenetic analysis revealed five putative metallothionein proteins in three other hymenoptera species. AmMT was characterized by cloning the full‐length coding sequence of the putative metallothionein. Recombinant AmMT was found to increase metal tolerance upon overexpression in Escherichia coli supplemented with Cd, Cu or Pb. Finally, in laboratory tests on honey bees, gene expression profiles showed a dose‐dependant relationship between Cd, Cu and Pb concentrations present in food and AmMT expression, while field experiments showed induction of AmMT in bees from an industrial site compared to those from an urban area. These studies suggest that AmMT has metal binding properties in agreement with a possible role in metal homeostasis. Further functional and structural characterization of metallothionein in honey bees and other Hymenoptera are necessary.
Understanding the cellular stress response in honey bees will significantly contribute to their conservation. The aim of this study was to analyze the response of the antioxidative enzymes superoxide ...dismutase and catalase in honey bees related to the presence of toxic metals in different habitats. Three locations were selected: (i) Tunovo on the mountain Golija, as control area, without industry and large human impact, (ii) Belgrade as urban area, and (iii) Zajača, as mining and industrial zone. Our results showed that the concentrations of lead (Pb) in whole body of bees vary according to habitat, but there was very significant increase of Pb in bees from investigated industrial area. Bees from urban and industrial area had increased expression of both Sod1 and Cat genes, suggesting adaptation to increased oxidative stress. However, in spite increased gene expression, the enzyme activity of catalase was lower in bees from industrial area suggesting inhibitory effect of Pb on catalase.
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•GC–MS sugar/polyol pattern for non- vs. diapausing O. nubilalis larvae was analyzed.•Glycerol, trehalose, sorbitol, mio-inositol, glucose and fructose were identified.•Glycerol and ...trehalose are the most abundant compounds in diapausing larvae.•In mid diapause, cold induced elevated glycerol and reduction of other polyols.•Low temperature increased content of all tested sugars at the end of diapause.
The European corn borer (ECB, Ostrinia nubilalis Hbn.) is a major pest in temperate regions of Europe and North America. Fifth instar ECB larvae enter diapause before winter and gradually develop cold hardiness. Here we investigated the combined influence of diapause phase and low temperature on sugar and polyol content in ECB larvae. Larvae in mid-diapause or diapause termination were acclimated at 5 °C, −3°C or −16 °C, and sugar and polyol content was measured using GC–MS. Control GC–MS measurements were conducted on untreated non-diapausing larvae. We detected differences in polyol (glycerol, sorbitol, myo-inositol) and sugar (trehalose, fructose, glucose) levels in diapausing versus non-diapausing larvae. Glycerol and trehalose were the most abundant of all analyzed cryoprotective compounds in diapausing larvae. Exposure of diapausing larvae to decreasing temperatures induced changes in polyol and sugar levels that depended on the phase of diapause. In mid-diapause larvae, decreasing temperatures induced a significant increase in glycerol and a decrease in sorbitol and myo-inositol. In larvae at diapause termination, polyol content was lower and less influenced by decreasing temperatures. In contrast, sugar levels were lower in larvae at mid-diapause versus diapause termination. Exposure of larvae to −16 °C induced a significant increase in the levels of all detected sugars. In particular, glucose levels were significantly higher in larvae at diapause termination following exposure to −16 °C. We propose that this shift toward sugar synthesis following low temperature exposure in larvae at diapause termination is a consequence of NADPH dependent polyol synthesis, and may be a mechanism for preservation of carbon reserves needed for post-diapause development.
Diapause is a state of arrested development during which insects cope with many external and internal stressful factors. European corn borer, Ostrinia nubilalis, overwinters as a fifth instar ...freeze-tolerant diapausing larva. In order to explore diapause-linked stress tolerance processes, the expression of selected genes coding for stress-related proteins—glutathione S-transferase (Gst), thioredoxin (Trx), glutaredoxin (Grx), ferritin (Fer), metallothionein (Mtn), and heat shock proteins Hsp90, Hsc70, Hsp20.4, and Hsp20.1—was assessed in the fat body of diapause-destined, warm (22°C) and cold (5°C) acclimated diapausing larvae using the quantitative real-time PCR. Gene expression was normalised to mRNA transcripts for Actin and Rps03, and relative expression was calculated using non-diapausing larvae as a control group. During the initiation phase of diapause, the abundance of mRNA transcripts of Grx, Hsp90, Hsc70, and Hsp20.1 was significantly upregulated, Trx, Fer, Mtn, and Hsp20.1 were unchanged, while only Gst was clearly downregulated in comparison to non-diapause control. Later, in the early phase of diapause, the expression of most genes (except Trx and Hsp20.1) was upregulated in warm-acclimated larvae, while only Trx and Hsp90 were upregulated in cold-acclimated larvae. Furthermore, the relative expression of all genes (except Trx) increased gradually throughout the diapause in cold-acclimated larvae. This result indicates that the half-life of mRNAs is prolonged during diapause at low temperature, which may lead to a gradual accumulation of mRNA transcripts. Our results show that both diapause programming and temperatures affect the expression of stress-related genes in Ostrinia nubilalis.
Retinopathy of prematurity (ROP) is a vascular proliferative disorder of
retina, that causes visual impairment in premature children. Beside well
known risk factors such as short gestational age, low ...birth weight and early
oxygen exposure, genetic susceptibility is considered as a risk factor for
development of the disease. The aim of our study was to explore the
association of T-786C and 4a/b eNOS gene polymorphisms with the development
of severe ROP. Study included 174 preterm infants, 84 with ROP and 90 as a
control group. No differences have been observed in genotypes and alleles
distributions of eNOS T-786C and eNOS 4a/b polymorphisms between two analyzed
groups. There was significant difference in female infants by dominant model
for 4a/b genotypes (4bb/4ba+4aa). Namely, female infants in ROP group were
more frequently carriers of 4ba and 4aa genotypes than female infants in
control group (p=0.037). Analysis of association between 4a/b eNOS
polymorphism and ROP among preterm infants have not shown statistically
significant association (p=0.288). Gestational age values by recessive model
(4bb+4ba/4aa) were significantly lower in infants with 4aa genotype (t=2.034
p=0.044). Almost all detected 4aa genotypes were present in the group of
infants with gestational age under 30 weeks (p=0.032), but multivariate
linear regression analysis does not show association of 4a/b genotypes with
gestational age of premature infants. According to results of the present
study T-786C and 4a/b polymorphisms of the eNOS gene may not be the risk
factors for the manifestation of severe ROP in Serbian infants.
Introduction: In hypoxic newborns requiring oxygen, lipid peroxidation affects the peripheral blood lipids. Objectives: Determine the influence of perinatal oxygen therapy for hypoxia on serum lipid ...concentrations on the second day of life. Materials and Methods: Our study included 50 newborns with perinatal hypoxia requiring oxygen and 50 healthy newborns without oxygen therapy. Arterialized capillary blood was taken for categorization of hypoxia (pO2) after birth in both groups. Lipid concentrations: total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), and triglycerides (TG) were measured on day 2 in both groups. Results: TC, LDL, HDL, TG, HC03 levels were statistically lower in the study group compared to the control one, while pCO2 and BE levels were statistically higher in newborns with perinatal hypoxia. Conclusion: Lower lipid levels in hypoxic newborns may suggest that circulating lipids are oxidized, peroxidized, and removed from the peripheral circulation.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Introduction: Hypocalcemia in preterm infants could occurs as early or late. Causes of late onset of hypocalcaemia: maternal vitamin D deficiency, metabolic syndromes, congenital abnormalities, ...iatrogenic (transfusion, bicarbonate therapy, phototherapy, antibiotics). Case report: The authors describe the occurrence of late hypocalcemia following transfusion of erythrocytes to the second newborn from a twin pregnancy born prematurely in the 32/33 week of gestation. Mother is diabetic and has hypertension, edema, hypothyroidism, and preeclampsia during pregnancy. Due to the detected pyelectasis in newborn, prophylactic use of cephalexin was introduced. At the end of the first month of life, anemia appear indicating a transfusion. The infant received 50 ml an O+ leukodepleted RBC transfusion. Immediately after transfusion was completed, there is a short-term deterioration of the general condition. Cyanosis, stiffness, trismus, and bradycardia appear within a few seconds. DAT was negative, bilirubin in the reference range. After transfusion, laboratory, echosonographic examination, neurological examination, EEG and ECG showed normal results. It was concluded that the adverse reaction was probably caused by transfusion. Conclusion: In preterm infants, hypocalcaemia may occur during transfusion due to citrate overload. Children of diabetic mothers, on antibiotic and photo therapy are at higher risk of developing hypocalcemia. Future studies should evaluate incidence rate of adverse transfusion reactions in newborns.
The phenomenon of fabric deformation can be observed not only keeping in mind the type of material, the raw material, geometric and constructive parameters, but also the conditions which which ...material is exposed under action of tensile force (the size of force, time, velocity of acting and so on). Investigates the influence of the tensile force size on total deformation as well as the deformation components: elastic, viscoelastic and plastic. Reports an experiment conducted on clothing wool fabrics (18 different samples) which were exposed to various tensile forces (5, 10, 15, 20, 25, 30 and 35 per cent of breaking force) during 15 minutes. After this time limit had expired, their relaxation in a period of 24 hours was examined. From the diagrams of fabric relaxation (126 diagrams), determines deformation components and presents a summary using diagrams. On the basis of imposed analysis claims it can be stated that elastic deformation component predominates while no plastic deformation exists at lower values of tensile force.
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