Phototransduction in Anuran Green Rods: Origins of Extra-Sensitivity

Green rods (GRs) represent a unique type of photoreceptor to be found in the retinas of anuran amphibians. These cells harbor a cone-specific blue-sensitive visual pigment but exhibit morphology of the outer segment typical for classic red rods (RRs), which makes them a perspective model object for studying cone–rod transmutation. In the present study, we performed detailed electrophysiological examination of the light sensitivity, response kinetics and parameters of discrete and continuous dark noise in GRs of the two anuran species: cane toad and marsh frog. Our results confirm that anuran GRs are highly specialized nocturnal vision receptors. Moreover, their rate of phototransduction quenching appeared to be about two-times slower than in RRs, which makes them even more efficient single photon detectors. The operating intensity ranges for two rod types widely overlap supposedly allowing amphibians to discriminate colors in the scotopic region. Unexpectedly for typical cone pigments but in line with some previous reports, the spontaneous isomerization rate of the GR visual pigment was found to be the same as for rhodopsin of RRs. Thus, our results expand the knowledge on anuran GRs and show that these are even more specialized single photon catchers than RRs, which allows us to assign them a status of “super-rods”.

Biotic Relations Between Pathogenic Leptospires And Green Algae

Leptospira interrogans spirochetes belong to a group of pathogens of particularly dangerous infections that cause leptospirosis in many species of wild, farm and domestic animals, as well as humans. Significant economic damage caused by this disease to livestock around the world, numerous cases of death from leptospirosis, and mainly waterborne transmission of the infection determine the topicality of studying all the aspects of the existence of L. interrogans in freshwater ecosystems. The objective of our study was to determine the nature of ecological relationships between L. interrogans and green algae. We used green algae of the Desmodesmus brasiliensis species as a model object. In the experiments, sterile algae culture filtrates were added to L. interrogans containers grown at 27–28 °C. Comparison of the content of spirochete cells in the experiment and control samples, conducted 24 hours after exposure, showed that the reproduction of L. interrogans is markedly inhibited in the samples containing algae secretions at the dilutions of 1:10 and 1:100. In order to reduce resistance to the allelopathic influence of D. brasiliensis algae, leptospira strains were located as follows: Pomona, Australis, Hebdomadis, Canicola, Sejroe, Icterohaemorrhagiae, Grippotyphosa, Tarassovi. The obtained results indicate a complex intraspecific structure of L. interrogans and their high ecological plasticity. In addition, experimental data indicate that, due to the release of biologically active substances into the aquatic environment, green algae have the potential to affect the dynamics of a number of leptospirosis pathogens in situ. Given the important epidemiological and epizootic significance of pathogenic leptospira, further research is necessary to determine the patterns of their interactions and existence in the environment.

Epiphytic lichen cover of collection trees of arboretum of the Botanical Garden of Petrozavodsk State University

At present, 264 species of lichens and allied fungi have been recorded for the territory of the BotanicalGarden of Petrozavodsk State University (Republic of Karelia) and 112 species have been found in its arboretum, wheremore than 200 species of introduced trees grow. The paper presents the results of studying the features of the epiphyticlichen cover of the collection trees of the arboretum of the Botanical Garden of PetrSU (Republic of Karelia). Results of thestudy are based on 1662 descriptions of the epiphytic lichen cover on 209 trees of coniferous species and 1150 descriptions –on 143 deciduous introduced species.The average total projective cover of lichens on the trunks of the studied coniferous introduced species reaches 18 % atthe trunk base, and 19 % – at a height of 130 cm above the ground. The number of species in the descriptions of epiphyticlichen cover varies from 0 to 12 (0.8 in average). The highest values of the projective cover of lichens and the numberof species in the descriptions were observed on the trunks of conifers of the genus Pinus, the lowest – on the trunks oftrees of the genus Thuja. The average total projective cover of lichens on the trunks of the studied deciduous introducedspecies was 8 % at the base, and 25 % – at a height of 130 cm above the ground. The number of species in the descriptionvaries from 0 to 9 (1.0 in average). The highest values of the projective cover of lichens and the number of species in thedescription are noted on the trunks of the genus Quercus, the lowest – on the trunks of trees of the genus Ulmus. Collectiontrees of arboretum tree represent a model object for observing the features of the formation of the epiphytic lichen cover

The use of model objects in evaluating the effectiveness of DEET-based repellent agents for individual protection against blood-sucking arthropods

With the aim of unifying and simplifying the assessment of categories of the effectiveness of the repellents funds audited 473 studies 245 samples of repellent remedies on the basis of DEET in various formulations, made in 1995–2019 employees of the Scientific Research Disinfесtology Institute in laboratory and in field conditions. The experiments were conducted in parallel with the standards of the corresponding or expected categories of effectiveness of repellent remedies. The concordance of the results of standard laboratory experiments on a model object Ae. aegypti mosquitoes and the results obtained from testing repellent agents against natural populations of flying blood-sucking insects and taiga ticks is proved. The effectiveness of repellent remedies based on other repellent substances, as well as the effectiveness against other species, should continue to be investigated in full-scale conditions for individuals of natural populations. These remedies should be included in the system of categories of effectiveness of repellent products.

Social Distancing Detector using YOLO v3 Image Processing Algorithm

The lack of public awareness and negligence, the pandemic due to coronavirus(covid19) has brought a global crisis with its deadly spread to more than 180 countries, and about 147 million confirmed cases along with 3.11 million deaths globally as of 26th April 2021. Due to the absence of the vaccine against the covid19 the world has suffered a lot. Though scientists have developed several vaccines then also the pandemic is still out of control so therefore the only feasible option available to us is social distancing. And this notion motivated us to bring up the idea of a social distancing detector using image processing which includes a deep learning framework for automation task monitoring. The framework utilizes the YOLO v3 model object detection model to separate moving people from the background and to detect people by using bounding boxes. The basic idea of this article is to analyze the social distancing violation index rate that how many people violate the rule of social distancing in a particular interval of time.