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Abstract: In animal contests, communicating aggressive motivation is most often mediated by visual or acoustic signals, while chemical signals are not expected to serve such a function since they are less able to be modulated by the sender during the changing behavioral context. We describe a rare example of ephemeral olfactory signals in terrestrial animals, signals that are emitted via protrusive scent glands in male cave crickets Troglophilus neglectus (Orthoptera, Rhaphidophoridae) to reflect the state of the signaler’s aggression. We correlate the intensity of behaviorally expressed aggression of the individuals in dyadic contests with the frequency and extent of their gland tissue protrusion, the latter serving as an indication of the amount of released odor. We detected large amounts of odor release during brief gland protrusions, and the absence of its release during gland retraction. Males protruded the glands during and after encountering a rival, with the degree of protrusion increasing with the intensity of the signalers’ aggression. During the encounters, the degree of gland protrusion increased most strongly with the occurrence of the elevated body posture, directly preceding the attack. This degree was significantly higher in encounter winners than in losers displaying such posture, suggesting the highly important role of the released odor for contest resolution. After the encounters, glands were protruded almost exclusively by winners, apparently announcing victory. We tested for the function of the olfactory signals also directly, by preventing gland tissue protrusion in symmetric and asymmetric treatments of the contestants. Treating only the dominant individuals decreased the percentage of encounters they won by over 60%, while treating both contestants elicited a significant increase in the frequency and duration of fights. During contests, the olfactory signals of T. neglectus apparently function as a highly effective threat, which prevents maximal contest escalation and decreases the conflict-related costs.
Keywords: animal behaviour, bioacoustics, aggression
Published in DiRROS: 25.07.2024; Views: 340; Downloads: 219
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Abstract: Next generation sequencing (NGS) technologies are becoming routinely employed in different fields of virus research. Different sequencing platforms and sample preparation approaches, in the laboratories worldwide, contributed to a revolution in detection and discovery of plant viruses and viroids. In this work, we are presenting the comparison of two RNA sequence inputs (small RNAs vs. ribosomal RNA depleted total RNA) for the detection of plant viruses by Illumina sequencing. This comparison includes several viruses, which differ in genome organization and viroids from both known families. The results demonstrate the ability for detection and identification of a wide array of known plant viruses/viroids in the tested samples by both approaches. In general, yield of viral sequences was dependent on viral genome organization and the amount of viral reads in the data. A putative novel Cytorhabdovirus, discovered in this study, was only detected by analysing the data generated from ribosomal RNA depleted total RNA and not from the small RNA dataset, due to the low number of short reads in the latter. On the other hand, for the viruses/viroids under study, the results showed higher yields of viral sequences in small RNA pool for viroids and viruses with no RNA replicative intermediates (single stranded DNA viruses).
Keywords: next generation sequencing, small RNA, ribosomal RNA depleted total RNA, detection, plant viruses, plant viroids
Published in DiRROS: 25.07.2024; Views: 349; Downloads: 210
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Abstract: Accurate and precise nucleic-acid quantification is crucial for clinical and diagnostic decisions, as overestimation or underestimation can lead to misguided treatment of a disease or incorrect labelling of the products. Digital PCR is one of the best tools for absolute nucleic-acid copy-number determination. However, digital PCR needs to be well characterised in terms of accuracy and sources of uncertainty. With droplet digital PCR, discrepancies between the droplet volume assigned by the manufacturer and measured by independent laboratories have already been shown in previous studies. In the present study, we report on the results of an inter-laboratory comparison of different methods for droplet volume determination that is based on optical microscopy imaging and is traceable to the International System of Units. This comparison was conducted on the same DNA material, with the examination of the influence of parameters such as droplet generators, supermixes, operators, inter-cartridge and intra-cartridge variability, and droplet measuring protocol. The mean droplet volume was measured using a QX200™ AutoDG™ Droplet Digital™ PCR system and two QX100™ Droplet Digital™ PCR systems. The data show significant volume differences between these two systems, as well as significant differences in volume when different supermixes are used. We also show that both of these droplet generator systems produce droplets with significantly lower droplet volumes (13.1%, 15.9%, respectively) than stated by the manufacturer and previously measured by other laboratories. This indicates that to ensure precise quantification, the droplet volumes should be assessed for each system.
Keywords: droplet digital PCR, droplet volume, DNA quantification, optical microscopy imaging
Published in DiRROS: 25.07.2024; Views: 373; Downloads: 270
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Abstract: Several recent studies have demonstrated the great potential for exploiting semiochemicals in ecology and conservation studies. The cerambycid beetle Rosalia alpina represents one of the flagship species of saproxylic insect biodiversity in Europe. In recent years its populations appear to have declined substantially, and its range has shrunk considerably as a result of forest management and urbanization. Here, we collected volatile chemicals released by males and females of R. alpina. Analyses of the resulting extracts revealed the presence of a single male-specific compound, identified as a novel alkylated pyrone structure. In field bioassays in Slovenia, traps baited with the synthesized pyrone captured both sexes of R. alpina, indicating that the pyrone functions as an aggregation pheromone. Our results represent the first example of a new structural class of pheromones within the Cerambycidae, and demonstrate that pheromone-baited traps can provide a useful tool for sampling R. alpina. This tool could be particularly useful in the ongoing development of conservation strategies for the iconic but endangered Alpine longicorn.
Keywords: pheromones, beetles, plants, endangered species, conservation science
Published in DiRROS: 25.07.2024; Views: 359; Downloads: 402
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Abstract: In Slovenia, cancer care services were exempt from government decrees for COVID-19 containment. Nevertheless, cancer control can be impacted also by access to other health services and changes in health-seeking behaviour. In this follow up study, we explored changes in cancer burden and cancer care beyond the first months after the onset of the COVID-19 epidemic.Materials and methods. We analysed routinely collected data for the period January 2019 through July 2022 from three sources: (1) pathohistological and clinical practice cancer notifications from two major cancer centres in Ljubljana and Maribor (source: Slovenian Cancer Registry); (2) referrals issued for oncological services (source: e-referral system); and (3) outpatient appointments and diagnostic imaging performed (source: administrative data of the Institute of Oncology Ljubljana – IOL). Additionally, changes in certain clinical and demographic characteristics in patients diagnosed and treated during the epidemic were analysed using the Hospital-Based Cancer Registry of the IOL (period 2015–2021).Results. After a drop in referrals to follow-up cancer appointments in April 2020, in June-August 2020, there was an increase in referrals, but it did not make-up for the drop in the first wave; the numbers in 2021 and 2022 were even lower than 2020. Referrals to first cancer care appointments and genetic testing and counselling increased in 2021 compared to 2019 and in 2022 increased further by more than a quarter. First and follow-up outpatient appointments and cancer diagnostic imaging at the IOL dropped after the onset of the epidemic in March 2020 but were as high as expected according to 2019 baseline already in 2021. Some deficits remain for follow-up outpatients’ appointments in surgical and radiotherapy departments. There were more CT, MRI and PET scans performed during the COVID-19 period than before. New cancer diagnoses dropped in all observed years 2020, 2021 and until July 2022 by 6%, 3% and 8%, respectively, varying substantially by cancer type. The largest drop was seen in the 50−64 age group (almost 14% in 2020 and 16% in 2021), while for patients older than 80 years, the numbers were above expected according to the 2015–2019 average (4% in 2020, 8% in 2021).Conclusions. Our results show a varying effect of COVID-19 epidemic in Slovenia for different types of cancers and at different stages on the patient care pathway – it is probably a mixture of changes in health-seeking behaviour and systemic changes due to modifications in healthcare organisation on account of COVID-19. A general drop in new cancer cases reflects disruptions in the pre-diagnostic phase and could have profound long-term consequences on cancer burden indicators.
Keywords: cancer, covid-19, delay in diagnosis
Published in DiRROS: 25.07.2024; Views: 370; Downloads: 223
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