First report of Trichoderma afroharzianum causing seed rot on maize in Italy

Maize (Zea mays L.) is a cereal crop of great economic importance in Italy; production is currently of 60,602,320 t, covering 588,597 ha (ISTAT 2021). Trichoderma species are widespread filamentous fungi in soil, well known and studied as biological control agents (Vinale et al., 2008). Seeds of a yellow grain hybrid (class FAO 700, 132 days) were collected in September 2020 from an experimental field located in Carmagnola (TO, Italy: GPS: 44°53'11.0"N 7°40'60.0"E) and tested with blotter test (Warham et al., 1996) to assess their phytosanitary condition. Over the 400 seeds tested, more than 50% showed rotting and development of green mycelium typical of the genus Trichoderma. Due to the high and unexpected percentage of decaying kernels, ten colonies were identified by morphological and molecular methods. Single conidia colonies of one Trichoderma (T5.1) strain were cultured on Potato Dextrose Agar (PDA) for pathogenicity tests, and on PDA and Synthetic Nutrient-Poor Agar (SNA) for morphological and molecular identification. The colonies grown on PDA and SNA showed green, abundant, cottony, and radiating aerial mycelium, and yellow pigmentation on the reverse. Colony radius after 72 h at 30°C was of 60-65 mm on PDA and of 50-55 mm on SNA. The isolates produced one cell conidia 2.8 - 3.8 µm long and 2.1 - 3.6 µm wide (n=50) on SNA. Conidiophores and phialides were lageniform to ampulliform and measured 4.5 – 9.7 µm long and 1.6 – 3.6 µm wide (n=50); the base measure 1.5 – 2.9 µm wide and the supporting cell 1.4 – 2.8 µm wide (n=50). The identity of one single-conidia strain was confirmed by sequence comparison of the internal transcribed spacer (ITS), the translation elongation factor-1α (tef-1α), and RNA polymerase II subunit (rpb2) gene fragments (Oskiera et al., 2015). BLASTn searches of GenBank using ITS (OL691534) the partial tef-1α (OL743117) and rpb2 (OL743116) sequences of the representative isolate T5.1, revealed 100% identity for rpb2 to T. afroharzianum TRS835 (KP009149) and 100% identity for tef-1α to T. afroharzianum Z19 (KR911897). Pathogenicity tests were carried out by suspending conidia from a 14-days old culture on PDA in sterile H2O to 1×106 CFU/ml. Twenty-five seeds were sown in pots filled with a steamed mix of white peat and perlite, 80:20 v/v, and maintained at 23°C under a seasonal day/night light cycle. Twenty primary ears were inoculated, by injection into the silk channel, with 1 ml of a conidial suspension of strain T5.1 seven days after silk channel emergence (BBCH 65) (Pfordt et al., 2020). Ears were removed four weeks after inoculation and disease severity, reaching up to 75% of the kernels of the twenty cobs, was assessed visually according to the EPPO guidelines (EPPO, 2015). Five control cobs, inoculated with 1 ml of sterile distilled water were healthy. T. afroharzianum was reisolated from kernels showing a green mold developing on their surface and identified by resequencing of tef-1α gene. T. afroharzianum has been already reported on maize in Germany and France as causal agent of ear rot of maize (Pfordt et al. 2020). Although several species of Trichoderma are known to be beneficial microorganisms, our results support other findings that report Trichoderma spp. causing ear rot on maize in tropical and subtropical areas of the world (Munkvold and White, 2016). The potential production of mycotoxins and the losses that can be caused by the pathogen during post-harvest need to be explored. To our knowledge this is the first report of T. afroharzianum as a pathogen of maize in Italy.

Differences in running performance of single- and group-housed mice

Mice are one of several common animal models in neuroscience and mouse behavior is becoming increasingly relevant. Mice are housed either in groups or alone in standard cages during which they show a variety of different behaviors. Moreover, housing conditions might alter the behavior of the mice as do social interactions. When given access to running wheels as an environmental enrichment, mice tend to run long distances preferentially during their dark cycle. However, it is currently not well understood whether and how mice utilize running wheels when single-housed or group-housed. Here we developed a low-cost running wheel data acquisition system to study running in adult C57BL/6 mice at high temporal resolution under different social conditions. As expected, adult C57BL/6 mice prefer to run in stretches during the dark cycle and mostly rest during the light cycle. When single-housed, running bouts occur independent from each other as indicated by an exponential decaying autocorrelation. In contrast, mice run ~50% less when housed in groups of n = 3 and their temporal pattern of running exhibits a power law decay in the autocorrelation indicative of potential social interactions. Our results demonstrate that running wheels are a limited resource for which mice compete for when they are group-housed, thereby reducing their overall running activity.

PHASE: A MATLAB Based Program for the Analysis of Drosophila Phase, Activity, and Sleep under Entrainment

The problem of entrainment is central to circadian biology. In this regard, Drosophila has been an important model system. Owing to the simplicity of its nervous system and the availability of powerful genetic tools, the system has shed significant light on the molecular and neural underpinnings of entrainment. However, much remains to be learned regarding the molecular and physiological mechanisms underlying this important phenomenon. Under cyclic light/dark conditions, Drosophila melanogaster displays crepuscular patterns of locomotor activity with one peak anticipating dawn and the other anticipating dusk. These peaks are characterized through an estimation of their phase relative to the environmental light cycle and the extent of their anticipation of light transitions. In Drosophila chronobiology, estimations of phases are often subjective, and anticipation indices vary significantly between studies. Though there is increasing interest in building flexible analysis software tools in the field, none incorporates objective measures of Drosophila activity peaks in combination with the analysis of fly activity/sleep in the same program. To this end, we have developed PHASE, a MATLAB-based program that is simple and easy to use and (i) supports the visualization and analysis of activity and sleep under entrainment, (ii) allows analysis of both activity and sleep parameters within user-defined windows within a diurnal cycle, (iii) uses a smoothing filter for the objective identification of peaks of activity (and therefore can be used to quantitatively characterize them), and (iv) offers a series of analyses for the assessment of behavioral anticipation of environmental transitions.

Nested calcium dynamics support daily cell unity and diversity in the suprachiasmatic nuclei of free-behaving mice

The suprachiasmatic nuclei (SCN) of the anterior hypothalamus host the circadian pacemaker that synchronizes mammalian rhythms with the day-night cycle. SCN neurons are intrinsically rhythmic, thanks to a conserved cell-autonomous clock mechanism. In addition, circuit-level emergent properties confer a unique degree of precision and robustness to SCN neuronal rhythmicity. However, the multicellular functional organization of the SCN is not yet fully understood. Although SCN neurons are well coordinated, experimental evidences indicate that some neurons oscillate out of phase in SCN explants, and possibly to a larger extent in vivo. Here, we used microendoscopic Ca2+i imaging to investigate SCN rhythmicity at a single cell resolution in free-behaving mice. We found that SCN neurons in vivo exhibited fast Ca2+i spikes superimposed upon slow changes in baseline Ca2+i levels. Both spikes and baseline followed a time-of-day modulation in many neurons, but independently from each other. Daily rhythms in basal Ca2+i were well coordinated, while spike activity from the same neurons peaked at multiple times of the light cycle, and unveiled clock-independent interactions at the multicellular level. Hence, fast Ca2+i spikes and slow changes in baseline Ca2+i levels highlighted how diverse activity patterns could articulate within the temporal network unity of the SCN in vivo, and provided support for a multiplex neuronal code in the circadian pacemaker.

NADH inhibition of SIRT1 links energy state to transcription during time-restricted feeding

In mammals, circadian rhythms are entrained to the light cycle and drive daily oscillations in levels of NAD+, a cosubstrate of the class III histone deacetylase sirtuin 1 (SIRT1) that associates with clock transcription factors. Although NAD+ also participates in redox reactions, the extent to which NAD(H) couples nutrient state with circadian transcriptional cycles remains unknown. Here we show that nocturnal animals subjected to time-restricted feeding of a calorie-restricted diet (TRF-CR) only during night-time display reduced body temperature and elevated hepatic NADH during daytime. Genetic uncoupling of nutrient state from NADH redox state through transduction of the water-forming NADH oxidase from Lactobacillus brevis (LbNOX) increases daytime body temperature and blood and liver acyl-carnitines. LbNOX expression in TRF-CR mice induces oxidative gene networks controlled by brain and muscle Arnt-like protein 1 (BMAL1) and peroxisome proliferator-activated receptor alpha (PPARα) and suppresses amino acid catabolic pathways. Enzymatic analyses reveal that NADH inhibits SIRT1 in vitro, corresponding with reduced deacetylation of SIRT1 substrates during TRF-CR in vivo. Remarkably, Sirt1 liver nullizygous animals subjected to TRF-CR display persistent hypothermia even when NADH is oxidized by LbNOX. Our findings reveal that the hepatic NADH cycle links nutrient state to whole-body energetics through the rhythmic regulation of SIRT1.

Light intensity alters the effects of light-induced circadian disruption on glucose and lipid metabolism in mice

Circadian disruption induced by rotating light cycles has been linked to metabolic disorders. However, how the interaction of light intensity and light cycle affects metabolism under different diets remains to be explored. Eighty mice were first randomly stratified into the low- (LFD, n = 40) or high-fat diet (HFD, n = 40) groups. Each group was further randomly subdivided into four groups (n = 8-12 per group) in terms of different light intensities (lower [LI, 78 lx] or higher intensity [HI, 169 lx]) and light cycles (12 h light:12 h dark cycle or circadian-disrupting [CD] light cycle consisting of repeated 6-h light phase advancement). Body weight was measured weekly. At the end of the 16-week experiment, mice were sacrificed for serum and pathological analysis. Glucose and insulin tolerance tests were performed during the last 2 weeks. The CD cycle increased body weight gain, adipocyte area, glucose intolerance, and insulin resistance of LFD as well as HFD mice under HI but not LI condition. Moreover, the serum and hepatic triglyceride levels increased with LFD-HI treatment, regardless of light cycle. In addition, the CD cycle improved lipid and glucose metabolism under HFD-LI condition. In summary, the detrimental effects of the CD cycle on metabolism were alleviated under LI condition, especially in HFD mice. These results indicate that modulating light intensity is a potential strategy to prevent the negative metabolic consequences associated with jet lag or shift work.

Roles of Nanostructured Bimetallic Supported on Alumina-Zeolite (AZ) in Light Cycle Oil (LCO) Upgrading

Light cycle oil (LCO) is one of the major products in Fluid catalytic cracking (FCC) processes, and has drawbacks such as high aromatics, sulfur, and nitrogen contents, and low cetane number (CN). Hydro-upgrading is one of the most typical processes for LCO upgrading, and alumina-zeolite (AZ) is an effective hydrotreating catalyst support. This paper examined the effects of different bimetallic catalysts (CoMo/AZ, NiMo/AZ, and NiW/AZ) supported by AZ on hydro-upgrading of both model compounds and real LCO. CoMo/AZ preferred the direct desulfurization (DDS) route while the NiMo/AZ and NiW/AZ catalysts favored the desulfurization route through hydrogenation (HYD). The presence of nitrogen compounds in the feed introduced a competitive adsorption mechanism and reduced the number of available acid sites. Aromatics were partially hydrogenated into methyltetralines at first, and then further hydrogenated, cracked, and isomerized into methyldecalins, monocyclic, and methyltetralines isomers. CoMo/AZ is the best hydrodesulfurization (HDS) catalyst for the model compounds at low H2 pressure (550 psi) and for LCO at lower temperature (573 K), while NiMo/AZ performs the best for LCO at higher temperature (648 K). NiMo/AZ is the best hydrodenitrogenation (HDN) catalyst for LCO. The hydrodearomatization (HDA) performances of NiMo/AZ and NiW/AZ improved significantly and overwhelmingly higher than that of the CoMo/AZ when the H2 pressure was increased to 1100 psi.

Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night

Light plays a fundamental role in the ecology of organisms in nearly all habitats on Earth and is central for processes such as vision and the entrainment of the circadian clock. The poles represent extreme light regimes with an annual light cycle including periods of Midnight Sun and Polar Night. The Arctic Ocean extends to the North Pole, and marine light extremes reach their maximum extent in this habitat. During the Polar Night, traditional definitions of day and night and seasonal photoperiod become irrelevant since there are only “twilight” periods defined by the sun’s elevation below the horizon at midday; we term this “midday twilight.” Here, we characterize light across a latitudinal gradient (76.5° N to 81° N) during Polar Night in January. Our light measurements demonstrate that the classical solar diel light cycle dominant at lower latitudes is modulated during Arctic Polar Night by lunar and auroral components. We therefore question whether this particular ambient light environment is relevant to behavioral and visual processes. We reveal from acoustic field observations that the zooplankton community is undergoing diel vertical migration (DVM) behavior. Furthermore, using electroretinogram (ERG) recording under constant darkness, we show that the main migratory species, Arctic krill (Thysanoessa inermis) show endogenous increases in visual sensitivity during the subjective night. This change in sensitivity is comparable to that under exogenous dim light acclimations, although differences in speed of vision suggest separate mechanisms. We conclude that the extremely weak midday twilight experienced by krill at high latitudes during the darkest parts of the year has physiological and ecological relevance.