Fertility of male adult rats submitted to forced swimming stress

We investigated whether stress interferes with fertility during adulthood. Male Wistar rats (weighing 220 g in the beginning of the experiment) were forced to swim for 3 min in water at 32ºC daily for 15 days. Stress was assessed by the hot-plate test after the last stressing session. To assess fertility, control and stressed males (N = 15 per group) were mated with sexually mature normal females. Males were sacrificed after copulation. Stress caused by forced swimming was demonstrated by a significant increase in the latency of the pain response in the hot-plate test (14.6 ± 1.25 s for control males vs 26.0 ± 1.53 s for stressed males, P = 0.0004). No changes were observed in body weight, testicular weight, seminal vesicle weight, ventral prostate weight or gross histological features of the testes of stressed males. Similarly, no changes were observed in fertility rate, measured by counting live fetuses in the uterus of normal females mated with control and stressed males; no dead or incompletely developed fetuses were observed in the uterus of either group. In contrast, there was a statistically significant decrease in spermatid production demonstrated by histometric evaluation (154.96 ± 5.41 vs 127.02 ± 3.95 spermatids per tubular section for control and stressed rats, respectively, P = 0.001). These data demonstrate that 15 days of forced swimming stress applied to adult male rats did not impair fertility, but significantly decreased spermatid production. This suggests that the effect of stress on fertility should not be assessed before at least the time required for one cycle of spermatogenesis

CRISPR/Cas13 for the Control of Plant Viruses

Plant viruses are one of the main threats to crops and food security worldwide, being very difficult to monitor and control. Since there are no effective chemical products against plant viruses, using virus-resistant plants is often the only option. Many promising strategies have been developed to engineer virus resistance however, several setbacks have hampered their utility in agriculture. In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins are players that are involved in the adaptative immune systems against viruses. They have been found and studied over the past decade and can be used as a rapid and simplified technology to develop resistance to viruses overcoming a lot of challenges faced by other techniques. The first CRISPR/Cas system studied was very useful for DNA targeting, but more recently identified types, using Cas13 proteins, that can specifically cleave single-stranded RNA in eukaryotic cells, have enabled a host of new opportunities, especially since most plant viruses have RNA genomes. This chapter aims to bring together the most up-to-date information about CRISPR/Cas13 systems to control plant viruses. We also discuss the limitations and future challenges of the use of CRISPR/Cas13 to produce virus-resistant plants for sustainable agriculture

Multibiomarker interactions to diagnose and follow-up chronic exposure of a marine crustacean to Hazardous and Noxious Substances (HNS)

Integrated compensatory responses of physiological systems towards homeostasis are generally overlooked when it comes to analysing alterations in biochemical parameters indicative of such processes. Here an hypothesis-driven multivariate analysis accounting for interactive multibiomarker responses was used to investigate effects of long-term exposure of Carcinus maenas to Hazardous and Noxious Substances (HNS). Adult male crabs were exposed to low and high post-spill levels of acrylonitrile (ACN) or aniline (ANL) for 21d. Bioaccumulation, feeding behaviour, and biomarkers related to mode-of-action (MoA) (detoxification, neurotransmission and energy production) were evaluated over time. Distinct temporal patterns of response to low and high exposure concentrations were depicted, with a main set of interactive multibiomarker predictors identified for each HNS (five for ACN and three for ANL), useful to follow coupled evolvement of biomarker responses. ACN caused peripheral neurotoxic effects coupled with enhanced biotransformation and significant oxidative damage particularly relevant in gills. ANL elicited alterations in central neurotransmission affecting ventilation coupled with very low levels of oxidative damage in gills. Results indicate chronic toxicity data are determinant to improve HNS hazard assessment if the aim is to obtain reliable risk calculations, and develop effective predictive models avoiding overestimation but sufficiently protective. Accounting for multibiomarker interactions brought otherwise overlooked information about C. maenas responses and MoA of ACN and ANL. Accounting for biomarker interactions drastically improves the quality of the model to diagnose toxic effects. © 2018 ElsevierThis article is a result of INNOVMAR - Innovation and Sustainability in the Management and Exploitation of Marine Resources (reference NORTE-01-0145-FEDER-000035), ECOSERVICES, supported by NORTE2020, PORTUGAL2020 Partnership Agreement, through ERDF . This work was partially funded by Strategic Funding UID/Multi/04423/2013 through FCT and ERDF

Potential of dissimilatory nitrate reduction pathways in polycyclic aromatic hydrocarbon degradation

This study investigates the potential of an indigenous estuarine microbial consortium to degrade two polycyclic aromatic hydrocarbons (PAHs), naphthalene and fluoranthene, under nitrate-reducing conditions. Two physicochemically diverse sediment samples from the Lima Estuary (Portugal) were spiked individually with 25 mg L−1 of each PAH in laboratory designed microcosms. Sediments without PAHs and autoclaved sediments spiked with PAHs were run in parallel. Destructive sampling at the beginning and after 3, 6, 12, 30 and 63 weeks incubation was performed. Naphthalene and fluoranthene levels decreased over time with distinct degradation dynamics varying with sediment type. Next-generation sequencing (NGS) of 16 S rRNA gene amplicons revealed that the sediment type and incubation time were the main drivers influencing the microbial community structure rather than the impact of PAH amendments. Predicted microbial functional analyses revealed clear shifts and interrelationships between genes involved in anaerobic and aerobic degradation of PAHs and in the dissimilatory nitrate-reducing pathways (denitrification and dissimilatory nitrate reduction to ammonium - DNRA). These findings reinforced by clear biogeochemical denitrification signals (NO3 − consumption, and NH4 + increased during the incubation period), suggest that naphthalene and fluoranthene degradation may be coupled with denitrification and DNRA metabolism. The results of this study contribute to the understanding of the dissimilatory nitrate-reducing pathways and help uncover their involvement in degradation of PAHs, which will be crucial for directing remediation strategies of PAH-contaminated anoxic sediments. © 2018 ElsevierThe authors acknowledge the reviewers for their valuable comments and suggestions, which were helpful in improving the manuscript. This research was partially supported by the Structured Program of R&D&I INNOVMAR - Innovation and Sustainability in the Management and Exploitation of Marine Resources . The post-doctoral scholarship granted by Erasmus Mundus Interweave to T. de Sousa is greatly acknowledged. C. Magalhães acknowledges Investigator FCT program supported by FCT, funded by the European Social Fund through the Operational Program of Human Capital (POCH) . C. Teixeira acknowledges FCT for a postdoctoral grant (ref. SFRH/BPD/110730/2015 ) cofunded by MCTES and the European Social Fund through POCH/QEC . Appendix