RPS6 transcriptional modulation in neural tissues of Nauphoeta cinerea during streptozotocin-associated sugar metabolism impairment.

The use of insects to model molecular events that characterize degenerative conditions was originally met with scepticism. However, the discovery of insect insulin-like peptides in the 1970's and the demonstration of evolutionary conservation of insulin-related signalling from insects to mammals have highlighted the importance and reduced cost of insect models in biomedical research. Here, we expand on our earlier described modelling of streptozotocin-induced brain glucose metabolic disruption in Nauphoeta cinerea, using RNA-sequencing analysis to study the transcriptional and genetic signatures of degeneration and stress signalling when glucose levels are elevated in the brain of the lobster cockroach. Nymphs were randomly divided into three groups: Control (0.8% NaCl), and two single streptozotocin injection doses (74 nmol and 740 nmol). The transcriptional analyses featured a dysregulation of 226 genes at high dose STZ treatment and 278 genes at the low dose. Our mRNA-sequencing data showed that ribosomal protein genes were the most upregulated genes at both 74 and 740 nmol STZ treatment. We therefore used RT-qPCR and relative transcriptional methods to validate our proposed mechanism of brain glucose toxicity-induced degeneration in Nauphoeta cinerea, which involved the upregulation of ribosomal proteins and rpS6 regulators (mTORC1, protein kinases, casein kinase 1 and Death-associated protein kinase), the upregulation of MAPK cascades (RAS, ERK, P38 and JNK), alongside the downregulation of the PI3K/AKT cascade. Taken together, this study highlights the remarkable opportunity for Nauphoeta cinerea use as an experimental organism in hyperglycaemia, degeneration, and stress signalling.

Streptozotocin activates inflammation-associated signalling and antioxidant response in the lobster cockroach; Nauphoeta cinerea (Blattodea: Blaberidae).

Streptozotocin exhibits tropism to insulin-producing beta-cells in mammals and has been used to model diabetes-like phenotypes in insects. We have previously shown increased brain glucose levels and oxidative stress in STZ-treated nymphs of Nauphoeta cinerea. Here, we validate Nauphoeta cinerea as an experimental organism for studying STZ-induced metabolic disruptions by investigating the potential changes in the expression of inflammation and antioxidant related genes. Cockroaches were injected with 0.8% NaCl, 74 and 740 nmol of STZ. mRNA extracted from the head of cockroaches was used to estimate the RT-qPCR expression of inflammation and antioxidant genes. STZ-treatment upregulated the target genes of the JNK pathway (early growth factor response factor and reaper) but had no effect on PDGF-and VEGF-related factor 1. TOLL 1, the target gene of TOLL/NF-kB pathway was up regulated, while both the activator and target gene of the UPD3/JAK/STAT pathway [unpaired 3 and Suppressor of cytokine signalling at 36E] were upregulated. mRNA levels of primary antioxidants (superoxide dismutase and catalase) were increased in STZ treated nymphs but there was no effect on thioredoxins and Peroxiredoxin 4. Likewise, STZ treatment did not affect the expression of the delta class of the glutathione S-transferase gene family, but the sigma and theta classes of the GST family were upregulated. The STZ-induced N. cinerea gene expression modification demonstrates the involvement of primary antioxidants and the GST detoxification system in the cockroach oxidative stress response and buttresses the proposed crosstalk between inflammatory and redox pathways.

Transcriptomic and Proteomic Tools in the Study of Hg Toxicity: What Is Missing?

Mercury is a hazardous substance that has unique neurodevelopmental toxic effects in humans. However, the precise sequence of molecular events that culminate in Hg-induced neuropathology is still unknown. Though the omics studies have been generating an enormous amount of new data about Hg toxicity, our ability to interpret such a large quantity of information is still limited. In this opinion article, we will reinforce the necessity of new high throughput and accurate analytical proteomic methodologies, especially, thiol and selenol-proteome. Overall, we posit that improvements in thiol- and selenol-proteomic analyses will be pivotal in identifying the primary cellular targets of Hg. However, a better understanding of the complex cascades and molecular pathways involved in its toxicity will require extensive complementary studies in more complex systems.

Cyclophosphamide in Drosophila promotes genes and transposable elements differential expression and mitochondrial dysfunction.

Cyclophosphamide (CPA) is an alkylating agent used for cancer chemotherapy, organ transplantation, and autoimmune disease treatment. Here, mRNA sequencing and high-resolution respirometry were performed to evaluate the alterations of Drosophila melanogaster gene expression fed with CPA under acute (0.1 mg/mL, for 24 h) and chronic (0.05 mg/mL, for 35 days) treatments. Differential expression analysis was performed using Cufflinks-Cuffdiff, DESeq2, and edgeR software. CPA affected genes are involved in several biological functions, including stress response and immune-related pathways, oxi-reduction and apoptotic processes, and cuticle and vitelline membrane formation. In particular, this is the first report of CPA-induced mitochondrial dysfunction caused by the downregulation of genes involved with mitochondria constituents. CPA treatment also changed the transcription pattern of transposable elements (TEs) from the gypsy and copia superfamilies. The results presented here provided evidence of CPA mitochondrial toxicity mechanisms and that CPA can modify TEs transcription in Drosophila flies.

Protected Blend of Organic Acids and Essential Oils Improves Growth Performance, Nutrient Digestibility, and Intestinal Health of Broiler Chickens Undergoing an Intestinal Challenge.

The growing restriction of antibiotic growth promoters (AGP) use in farming animals has raised a concern regarding the viability of the animal production system. In this new context, feed additives with proven positive impact on intestinal health may be used as strategy to avoid losses on performance. The aim of this study was to evaluate the effects of a protected blend of organic acids and essential oils [P(OA+EO)] on growth performance, nutrient digestibility, and intestinal health of broiler chickens. A total of 1,080 Cobb × Cobb 500 male broilers were randomly distributed in four treatments with 10 replicates (27 birds/each). Treatments were as follow: non-challenged control; challenged control; AGP (enramycin at 10 g/t); and P(OA+EO) at 300 g/t. All birds on challenged groups were challenged with Eimeria spp. at 1 day and with Clostridium perfringens at 11, 12, and 13 days. Body weight gain (BWG), feed intake and feed conversion ratio (FCR) were evaluated until 42 days. At 17 days, one bird per pen was orally gavaged with fluorescein isothiocyanate-dextran (FITC-d) and blood samples were collected for FITC-d detection to assess intestinal permeability. At 21 days, apparent ileal nutrient and energy (IDE) digestibility, intestinal macroscopic and histologic alterations (ISI) and, expression of mucin2 (MUC2), claudin1 (CLDN1), and occludin (OCLN) genes in the jejunum were evaluated. From 1 to 42 days, birds from the non-challenged and P(OA+EO) groups had greater (P < 0.001) BWG compared to challenged control and AGP groups. The challenged control group presented the worst FCR (P < 0.001). IDE was 106 kcal/kg greater when broilers were fed P(OA+EO) compared to the challenged control group. Broilers supplemented with P(OA+EO) had improved intestinal integrity with lower blood FITC-d concentration and ISI scores, and greater expression of MUC2, CLDN1, and OCLN genes compared to the challenged control group (P < 0.05). In conclusion, the P(OA+EO) and the AGP led to increased growth performance, nutrient digestibility and intestinal health of challenged broilers. A marked difference occurred in favor of the P(OA+EO), suggesting that this blend may be used to improve intestinal health and broiler growth performance in AGP free programs.

Diversification in the South American Pampas: the genetic and morphological variation of the widespread Petunia axillaris complex (Solanaceae).

Understanding the spatiotemporal distribution of genetic variation and the ways in which this distribution is connected to the ecological context of natural populations is fundamental for understanding the nature and mode of intraspecific and, ultimately, interspecific differentiation. The Petunia axillaris complex is endemic to the grasslands of southern South America and includes three subspecies: P. a. axillaris, P. a. parodii and P. a. subandina. These subspecies are traditionally delimited based on both geography and floral morphology, although the latter is highly variable. Here, we determined the patterns of genetic (nuclear and cpDNA), morphological and ecological (bioclimatic) variation of a large number of P. axillaris populations and found that they are mostly coincident with subspecies delimitation. The nuclear data suggest that the subspecies are likely independent evolutionary units, and their morphological differences may be associated with local adaptations to diverse climatic and/or edaphic conditions and population isolation. The demographic dynamics over time estimated by skyline plot analyses showed different patterns for each subspecies in the last 100 000 years, which is compatible with a divergence time between 35 000 and 107 000 years ago between P. a. axillaris and P. a. parodii, as estimated with the IMa program. Coalescent simulation tests using Approximate Bayesian Computation do not support previous suggestions of extensive gene flow between P. a. axillaris and P. a. parodii in their contact zone.