Ergosterol and Fusarium mycotoxins content in two maize cultivars under different forms of nitrogen fertilizers

Mycotoxins are secondary metabolites produced by many filamentous fungi, such as Fusarium, and are widespread in nature and can adversely affect almost all organisms. Mycotoxins can be formed in very different conditions such as when plants are growing or in crops that are stored in improper conditions. One of the methods to prevent the formation of mycotoxins in powdered feed is using varieties of appropriate quality and proper mineral fertilization, primarily nitrogen. In this study, the concentration of ergosterol and mycotoxins in the kernels of two maize cultivars from different maturity groups in Poland during the harvest of 2011 and 2012 was investigated using HPLC methods. We aimed to analyse the concentration of ergosterol as a fungal biomass indicator and mycotoxins from two maize cultivars under six different forms of nitrogen fertilizers. The “stay‐green” hybrid ES Paroli was characterized by a significantly lower ergosterol and the ability to accumulate the mycotoxins, compared to the classic cultivar ES Palazzo. The varieties of maize that remain green for a longer time period, the so‐called stay‐green type, are characterized by a different coefficient of nitrogen remobilization compared to the classic hybrids. Their dynamics of growth and accumulation of nutrients indicates a nitrogen fertilization system, indicating that slow‐release fertilizers are potentially more adapted to the cycles of maize vegetation. Hence, compared to the classic variant, the “stay‐green” variety uses nitrogen more effectively from mineral fertilizers. Such hybrids are healthier and remain in good condition for a longer time; therefore, they are characterized by a lower pathogen pressure. Thus, the cultivation of such varieties can be considered as one of the elements of integrated maize production. We observed identical reactions of the studied experimental factors for both vegetation seasons, which indicates the lack of environmental impact on the functioning and interaction of experimental factors.     

Nematode ascaroside enhances resistance in a broad spectrum of plant–pathogen systems

Recognition of specific molecule signatures of microbes, including pathogens, induces innate immune responses in plants, as well as in animals. Analogously, a nematode pheromone, the ascaroside ascr#18, induces hallmark plant defences including activation of (a) mitogen‐activated protein kinases, (b) salicylic acid‐ and jasmonic acid‐mediated defence signalling pathways and (c) defence gene expression and provides protection to a broad spectrum of pathogens. Ascr#18 is a member of an evolutionarily conserved family of nematode signalling molecules and is the major ascaroside secreted by plant–parasitic nematodes. Here, we report the effects of ascr#18 on resistance in four of the major economically important crops: maize, rice, wheat and soybean to some of their associated pathogens. Treatment with low nanomolar to low micromolar concentrations of ascr#18 provided from partial to strong protection in seven of eight plant–pathogen systems tested with viruses, bacteria, fungi, oomycetes and nematodes. This research may have potential to improve agricultural sustainability by reducing use of potentially harmful agrochemicals and enhance food security worldwide.     

Energy conservation characterizes sleep in sharks

Sharks represent the earliest group of jawed vertebrates and as such, they may provide original insight for understanding the evolution of sleep in more derived animals. Unfortunately, beyond a single behavioural investigation, very little is known about sleep in these ancient predators. As such, recordings of physiological indicators of sleep in sharks have never been reported. Reduced energy expenditure arising from sustained restfulness and lowered metabolic rate during sleep have given rise to the hypothesis that sleep plays an important role for energy conservation. To determine whether this idea applies also to sharks, we compared metabolic rates of draughtsboard sharks (Cephaloscyllium isabellum) during periods ostensibly thought to be sleep, along with restful and actively swimming sharks across a 24 h period. We also investigated behaviours that often characterize sleep in other animals, including eye closure and postural recumbency, to establish relationships between physiology and behaviour. Overall, lower metabolic rate and a flat body posture reflect sleep in draughtsboard sharks, whereas eye closure is a poorer indication of sleep. Our results support the idea for the conservation of energy as a function of sleep in these basal vertebrates.     

Status and distribution of jaguarundi in Texas and Northeastern México: Making the case for extirpation and initiation of recovery in the United States

The jaguarundi (Puma yagouaroundi) is a small felid with a historical range from central Argentina through southern Texas. Information on the current distribution of this reclusive species is needed to inform recovery strategies in the United States where its last record was in 1986 in Texas. From 2003 to 2021, we conducted camera‐trap surveys across southern Texas and northern Tamaulipas, México to survey for medium‐sized wild cats (i.e., ocelots [Leopardus pardalis], bobcats [Lynx rufus], and jaguarundi). After 350,366 trap nights at 685 camera sites, we did not detect jaguarundis at 16 properties or along 2 highways (1050 km²) in Texas. However, we recorded 126 jaguarundi photographic detections in 15,784 trap nights on 2 properties (125.3 km²) in the northern Sierra of Tamaulipas, Tamaulipas, México. On these properties, latency to detection was 72 trap nights, with a 0.05 probability of detection per day and 0.73 photographic event rate every 100 trap nights. Due to a lack of confirmed class I sightings (e.g., specimen, photograph) in the 18 years of this study, and no other class I observations since 1986 in the United States, we conclude that the jaguarundi is likely extirpated from the United States. Based on survey effort and results from México, we would have expected to detect jaguarundis over the course of the study if still extant in Texas. We recommend that state and federal agencies consider jaguarundis as extirpated from the United States and initiate recovery actions as mandated in the federal jaguarundi recovery plan. These recovery actions include identification of suitable habitat in Texas, identification of robust populations in México, and re‐introduction of the jaguarundi to Texas.     

The Availability of Phosphorus and the Species Composition of the Spring Phytoplankton in Lake Erken

The spring development of phytoplankton and the phosphorus content were monitored intensively in Laken Erken during the springs of 1979 and 1980. The dominant species were dinoflagellates, mainly Woloszynskia ordinata and Peridinium aciculiferum, during the entire spring of 1979. The long period of ice-cover (21 weeks) favoured the motile species, which were able to utilize the available light immediately below the ice. A considerable vertical migration was noticed in March 1979. These large and slow-growing algae were able to store luxury phosphorus, and surplus phosphorus concentrations up to 12 μg P/l were measured, which corresponded to an algal content of 10 μg P/mg C. These values were more than twice as high as those recorded earlier in Lake Erken. Although a spring outburst of diatoms did not occur in 1979 and 1980, the algae were phosphorus-limited in May, as indicated by high alkaline phosphatase activity, low algal surplus phosphorus content and high inorganic N : P ratios.     

Phylodynamic Inference of Bacterial Outbreak Parameters Using Nanopore Sequencing

Nanopore sequencing and phylodynamic modeling have been used to reconstruct the transmission dynamics of viral epidemics, but their application to bacterial pathogens has remained challenging. Cost-effective bacterial genome sequencing and variant calling on nanopore platforms would greatly enhance surveillance and outbreak response in communities without access to sequencing infrastructure. Here, we adapt random forest models for single nucleotide polymorphism (SNP) polishing developed by Sanderson and colleagues (2020. High precision Neisseria gonorrhoeae variant and antimicrobial resistance calling from metagenomic nanopore sequencing. Genome Res. 30(9):1354–1363) to estimate divergence and effective reproduction numbers (R_e) of two methicillin-resistant Staphylococcus aureus (MRSA) outbreaks from remote communities in Far North Queensland and Papua New Guinea (PNG; n = 159). Successive barcoded panels of S. aureus isolates (2 × 12 per MinION) sequenced at low coverage (>5× to 10×) provided sufficient data to accurately infer genotypes with high recall when compared with Illumina references. Random forest models achieved high resolution on ST93 outbreak sequence types (>90% accuracy and precision) and enabled phylodynamic inference of epidemiological parameters using birth–death skyline models. Our method reproduced phylogenetic topology, origin of the outbreaks, and indications of epidemic growth (R_e > 1). Nextflow pipelines implement SNP polisher training, evaluation, and outbreak alignments, enabling reconstruction of within-lineage transmission dynamics for infection control of bacterial disease outbreaks on portable nanopore platforms. Our study shows that nanopore technology can be used for bacterial outbreak reconstruction at competitive costs, providing opportunities for infection control in hospitals and communities without access to sequencing infrastructure, such as in remote northern Australia and PNG.     

Mechanical vibration in “double-wound” magnetic field exposure coils

It has been suggested that “double-wound” (bifilar) exposure coils are capable of producing a sham environment in which hum and vibration will be “similar” to the field-exposed condition. We found by direct measurements in a bifilar coil system that vibration amplitude in sham and exposed conditions differed by a factor of 50 when our test system was driven at B = 10 mT. We also found that the normal laboratory environment can include vibrations of an intensity similar to that produced by the exposure system, although not necessarily of similar spectral distribution. © 1996 Wiley-Liss, Inc.