Molecular characterization and expression analysis of heat shock protein 70 and 90 from Hermetia illucens reared in a food waste bioconversion pilot plant

Embryotoxicity of polystyrene microplastics in zebrafish Daniorerio

In the recent years, increasing scientific and societal concern has been raised over the presence and accumulation of plastic debris in the environment and the effects of microplastics (MPs) that can easily interact with biota. In order to elucidate the impact of MPs at the critical development stages of freshwater fish species, a fish embryo toxicity test was herein performed on the zebrafish Danio rerio, exposed to 10 μm polystyrene MPs at 200 particles/mL for 120 hpf. After exposure, accumulation of MPs in larvae was measured, survival, hatching and larvae development were monitored and the oxidant/anti-oxidant responses and cellular detoxification evaluated. No impact on survival of developing zebrafish was revealed, but a moderate delay in hatching was observed. Alterations in larvae development were recorded with zebrafish exhibiting serious deformities, mainly at the level of column and tail, as well as a compromised integrity of the visual structure of the eyes. Moreover, increased levels of gene transcription involved in the oxidative stress (sod1, sod2 and cat) and in cellular detoxification (gst and cyp) were also detected in MPs-exposed zebrafish larvae. Overall, this research work provides new insights on the ecotoxicological impact of polystyrene MPs on the critical developmental stages of a freshwater fish species, therefore enhancing the current knowledge of the environmental risk posed by MPs to the aquatic ecosystem.

Functional characterization of four Hsp70 genes involved in high-temperature tolerance in Aphis aurantii (Hemiptera: Aphididae)

The tea aphid, Aphis aurantii (Boyer de Fonscolombe), is a serious pest that can infest many economically important plants. Tea aphids damage plants by directly sucking phloem sap, transmitting viruses, and secreting honeydew to cause sooty mold. At present, tea aphids has become one of the most important pests in tropical and subtropical tea plants. The heat shock protein 70 (Hsp70) is a key protein involved in heat stress tolerance. In this study, we cloned four Hsp70 genes that are highly expressed in tea aphids after heat shock. Bioinformatic analysis of the deduced amino acid sequences showed that these four AaHsp70s had a close genetic relationship to Hsp70 in Hemiptera insects and shared a conserved ATPase domain. After incubation at low (14 °C) or high (36 °C) temperature, the expression of four AaHsp70s was significantly up-regulated compared to the control (25 °C); however, the up-regulation of the AaHsp70s in the low-temperature treatment was far less than that of the high-temperature treatment. The ATPase activity of the four purified recombinant AaHsp70 proteins after high-temperature treatment was significantly increased compared to the control. In addition, these proteins effectively improved the heat tolerance of Escherichia coli in vivo. Our data indicate that AaHsp701, AaHsp702, AaHsp703, AaHsp704 play important roles in response to the high-temperature tolerance in tea aphids.

Assessment of the effectiveness of a novel BioFilm-Membrane BioReactor oil-polluted wastewater treatment technology by applying biomarkers in the mussel Mytilus galloprovincialis

Petrochemical industries and oil refineries are sources of hazardous chemicals into the aquatic environments, and often a leading cause of reduced oxygen availability, thus resulting in adverse effects in biota. This study is an expansion of our previous work on the assessment of the BioFilm-Membrane Bioreactor (BF-MBR) to mitigate the impact of oil-polluted wastewater on marine environments. Specifically, this study evaluated the reduction of selected chemical constituents (hydrocarbons and trace metals) and toxicity related to hypoxia and DNA damage to mussels Mytilus galloprovincialis, before and after treatment of oil-polluted wastewater with the BF-MBR. The application of a multidisciplinary approach provided evidence of the efficiency of BF-MBR to significantly reducing the pollutants load from oily contaminated seawaters. As result, the health status of mussels was preserved by a hypoxic condition due to oily pollutants, as evidenced by the modulation in the gene expression of HIF-1α and PHD and changes in the level of hypotaurine and taurine. Moreover, ameliorative effects in the energy metabolism were also found in mussel gills showing increased levels of glycogen, glucose and ATP, as well as a mitigated genotoxicity was revealed by the Micronucleus and Comet assays. Overall, findings from this study support the use of the BF-MBR as a promising treatment biotechnology to avoid or limiting the compromise of marine environments from oil pollution.

Characterization, expression profiling, and thermal tolerance analysis of heat shock protein 70 in pine sawyer beetle, Monochamus alternatus hope (Coleoptera: Cerambycidae)

Monochamus alternatus Hope (Coleoptera: Cerambycidae) warrants attention as a dominant transmission vector of the pinewood nematode, and it exhibits tolerance to high temperature. Heat shock protein 70 (HSP70) family members, including inducible HSP70 and heat shock cognate protein 70 (HSC70), are major contributors to the molecular chaperone networks of insects under heat stress. In this regard, we specifically cloned and characterized three MaltHSP70s and three MaltHSC70s. Bioinformatics analysis on the deduced amino acid sequences showed these genes, having close genetic relationships with HSP70s of Coleopteran species, collectively shared conserved signature structures and ATPase domains. Subcellular localization prediction revealed the HSP70s of M. alternatus were located not only in the cytoplasm and endoplasmic reticulum but also in the nucleus and mitochondria. The transcript levels of MaltHSP70s and MaltHSC70s in each state were significantly upregulated by exposure to 35-50°C for early 3 h, while MaltHSP70s reached a peak after exposure to 45°C for 2-3 h in contrast to less-upregulated MaltHSC70s. In terms of MaltHSP70s, the expression threshold in females was lower than that in males. Also, both fat bodies and Malpighian tubules were the tissues most sensitive to heat stress in M. alternatus larvae. Lastly, the ATPase activity of recombinant MaltHSP70-2 in vitro remained stable at 25-40°C, and this recombinant availably enhanced the thermotolerance of Escherichia coli. Overall, our findings unraveled HSP70s might be the intrinsic mediators of the strong heat tolerance of M. alternatus due to their stabilized structure and bioactivity.

Waste Valorization via Hermetia Illucens to Produce Protein-Rich Biomass for Feed: Insight into the Critical Nutrient Taurine

Insects have been recognized as sustainable alternative sources of nutrients for food and feed. The Black Soldier Fly (BSF), Hermetia illucens, is a particularly promising species for its great potential in the waste valorization to produce, during the bioconversion process, high-value fat and proteins that currently represent a valuable source for fish feed. The present study aims to evaluate the efficiency to use substrate proteins in two different BSF developmental stages as sustainable biotechnological tools for vegetable waste management. We provide insights into the nutritional values of both V instar larvae and prepupae in terms of valuable amino acids with special focus on taurine, a crucial nutrient for fish. Moreover, we cloned four key genes from BSF involved in the taurine biosynthesis pathway, 2-aminoethanethiol dioxygenase (Hiado), cysteine dioxygenase (Hicdo), cysteine sulfonate decarboxylase (Hicsad), and glutamate decarboxylase (Higad). The gene expression analysis in larvae and prepupae by qPCR showed development-specific profiles suggesting they influence the taurine content during BSF development. These findings showed peculiar phenotypes in larvae and prepupae that can be selected for different biotechnological applications as sustainable source of relevant amino acids and taurine to support the increasing demand for animal feed and aquafeed in the next decades.

Molecular characterization and expression patterns of Phenacoccus solenopsis (Hemiptera: Pseudococcidae) heat shock protein genes and their response to host stress

As a polyphagous insect, little is known at the molecular level about the effects of different host plants on physiological changes in Phenacoccus solenopsis. In this study, four heat shock protein (Hsp) genes (PsHsp60, PsHsp70, PsHsp90, and PsHsp20.7) were identified from the transcriptome of P. solenopsis. Analysis of Hsp expression levels revealed significant differences in Hsp gene expression levels in P. solenopsis fed on different host plants. In host conversion tests, the expression levels of PsHsp90 and PsHsp60 were upregulated after transfer of second instar nymphs from tomato to cotton. The expression levels of PsHsp70 and PsHsp20.7 were, respectively, significantly upregulated at 9 and 48 hr after transfer from tomato to Hibiscus. The results of this study aid molecular characterization and understanding of the expression patterns of Hsp genes during different developmental stages and host transfer of P. solenopsis.

Analysis of genetic variations of heat shock proteins Hsp70 and Hsp90 in Isaria farinosa strains from the Yunnan province of China

In the present study, the cDNA sequences of Hsp70 and Hsp90 genes of Isaria farinosa (designated IFHSP70 and IFHSP90) were cloned and characterized using multiple techniques of molecular biology and bioinformatics. The genetic differentiation of the two genes was investigated among 10 geographically separated populations distributed in the Yunnan province. The complete sequence of the IFHSP70 cDNA had a length of 2158 bp, and contained an open reading frame (ORF) of 1962 bp, encoding a 71-kDa polypeptide comprising of 653 amino acids. IFHSP90 cDNA had a length of 2144 bp, and contained an ORF of 2103 bp, encoding a polypeptide of 79.23 kDa, comprising of 700 amino acids. The deduced amino acid sequences of IFHSP70 and IFHSP90 shared high sequence identities with other fungi. Fundamental information pertaining to the protein families, signatures, and conserved motifs of Hsp70 and Hsp90 were also identified. Analysis of molecular variances (AMOVA) from the Hsp70 and Hsp90 genes showed that the genetic variation within-population (83.26%, 83.08%) was greater than among the populations (16.74%, 16.92%). The values of nucleotide diversity (Pi), haplotype diversity (Hd), coefficient of genetic differentiation (Fst), and gene flow (Nm) were calculated. For Hsp70, Pi = 0.0425, Hd = 0.888, Fst = 0.167, Nm = 1.24; For Hsp90, Pi = 0.0420, Hd = 0.894, Fst = 0.169, and Nm = 1.22. These data indicated that the genetic differentiation among 10 different geographical populations of I. farinosa was limited. This study describes, for the first time, cloning, characterization and identification of Isaria farinosa Hsp70 and Hsp90 genes, and provides a preliminary basis for exploring the genetic structure of the genus Isaria using the sequences of Hsp70 and Hsp90 as molecular markers.

Copper oxide nanoparticles induce the transcriptional modulation of oxidative stress-related genes in Arbacia lixula embryos

Copper oxide nanoparticles (CuO NPs) are widely used in various industrial applications, i.e. semiconductor devices, batteries, solar energy converter, gas sensor, microelectronics, heat transfer fluids, and have been recently recognized as emerging pollutants of increasing concern for human and marine environmental health. Therefore, the toxicity of CuO NPs needs to be thoroughly understood. In this study, we evaluated the potential role of oxidative stress in CuO NP toxicity by exploring the molecular response of Arbacia lixula embryos to three CuO NP concentrations (0.7, 10, 20 ppb) by investigating the transcriptional patterns of oxidative stress-related genes (catalase and superoxide dismutase) and metallothionein, here cloned and characterized for the first time. Time- and concentration-dependent changes in gene expression were detected in A. lixula embryos exposed to CuO NPs, up to pluteus stage (72 h post-fertilization, hpf), indicating that oxidative stress is one of the toxicity mechanisms for CuO NPs. These findings provide new insights into the comprehension of the molecular mechanisms underlying copper nanoparticle toxicity in A. lixula sea urchin and give new tools for monitoring of aquatic areas, thus corroborating the suitability of this embryotoxicity assay for future evaluation of impacted sites.

Comparisons of Expression Levels of Heat Shock Proteins (hsp70 and hsp90) From Anaphothrips obscurus (Thysanoptera: Thripidae) in Polymorphic Adults Exposed to Different Heat Shock Treatments

Heat shock proteins (Hsps) are prominent proteins that greatly contribute to insect survival under stress conditions. In this study, we cloned two Hsp transcripts (Aohsp70 and Aohsp90) from the grass thrip, Anaphothrips obscurus (Müller) (Thysanoptera: Thripidae), which is a polymorphic winged pest of corn and wheat. The cDNA sequences of Aohsp70 and Aohsp90 are 2382 and 2504 bp long, and encode proteins with calculated molecular weights of 70.02 kDa and 83.40 kDa, respectively. Aohsp90 was highly expressed in adults of both brachypters and macropters. Aohsp70 had different expression patterns in brachypters and macropters and was also highly expressed in the pupae of macropters. After adults were exposed to an ascending series of heat shocks, the expression of both Aohsp70 and Aohsp90 were up-regulated. In macropters and brachypters, the maximum induced levels of Aohsp70 (approximately 90-fold and 280-fold, respectively) were higher than Aohsp90 (approximately 2.4-fold and 1.8-fold, respectively). In addition, the up-regulation of Aohsp70 was significantly higher in brachypters than in macropters. Brachypters had a significantly higher Ltem50 (43.2°C) than macropters (42.5°C), which implied that brachypters are more tolerant to thermal stress than macropters. This study has shown that the expression patterns of Aohsp70 and Aohsp90 are variable among different life stages and thermal stress induced different levels of expressions in macropterous and brachypterous adults.

Effects of Oxygen Availability on Oxidative Stress Biomarkers in the Mediterranean Mussel Mytilus galloprovincialis

In aquatic environments, hypoxia and oxygen-deficient areas are increasing worldwide. Transitions in oxygen levels can influence the production of reactive oxygen species (ROS), eventually leading to oxidative stress. The transcriptional response of oxidative stress biomarkers was evaluated by qPCR in gill tissue from Mytilus galloprovincialis experimentally subjected to 48-h air exposure followed by 48-h re-oxygenation, as compared to normoxic control mussels. Superoxide dismutases (CuZnsod and Mnsod), catalase (cat), and glutathione S-transferase (gst) were over-expressed early after 8-h air exposure and returned to normoxic levels during re-oxygenation. Moreover, the mRNAs and protein expression patterns of heat shock proteins (HSP70 and HSP90) and metallothioneins (MT-10 and MT-20) were modulated by oxygen availability with increased levels during re-oxygenation suggesting the participation of these cytoprotective mechanisms in the physiological oxidative stress response when oxygen concentration was restored. Overall, the observed modulation of the oxidative stress-related and general stress genes indicates that M. galloprovincialis responds to changes in oxygen availability enhancing the antioxidant potential under low oxygen conditions for dealing with the oxidative burst during future re-oxygenation. The present investigation brings further insights in understanding how intertidal molluscs cope with short-term oxygen variations and gives useful biomarkers for environmental monitoring of hypoxic areas that are predicted to occur in the next future.