Browsing by Author "Nagwani, Amit Kumar"
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Item Applicable Life-History and Molecular Traits for Studying the Effects of Anhydrobiosis on Aging in Tardigrades(Multidisciplinary Digital Publishing Institute (MDPI), 2022-08-17) Nagwani, Amit Kumar; Kaczmarek, Łukasz; Kmita, HannaAnhydrobiosis is induced by loss of water and indicates dehydration tolerance. Survival of dehydration is possible through changes at different levels of organism organization, including a remarkable reduction in metabolic activity at the cellular level. Thus, anhydrobiosis may be regarded as an anti-aging strategy. Accordingly, two hypotheses named after popular stories, “Sleeping Beauty” and “The Picture of Dorian Gray”, were proposed to explain the effect of anhydrobiosis on aging. The two hypotheses predict the presence (The Picture of Dorian Gray) or absence (Sleeping Beauty) of observable aging symptoms for animals undergoing anhydrobiosis. Predictions of these hypotheses have rarely been tested, and the cellular level has not been addressed. Tardigrades appear to be a useful model for studying the effect of anhydrobiosis on aging, as they are able to enter and survive anhydrobiosis at any stage of life, although not with the same success for all species. In this review, we discuss anhydrobiosis and aging mechanisms as well as tardigrade diversity and indicate possible multilevel markers that can be used to study the impact of anhydrobiosis on tardigrade aging. This review provides data on tardigrade diversity that may also be useful for human aging studies.Item Poszukiwanie markerów starzenia się niesporczaka Paramacrobiotus experimentalis(2024) Nagwani, Amit Kumar; Kmita, Hanna. Promotor; Kaczmarek, Łukasz. PromotorZakłada się, że starzenie się jest nieuniknione, nieodwracalne i postępujące, ale dostępne dane wskazują, że starzenie się niesporczaków może być opóźnione przez kryptobiozę. Możliwość tę uwzględnia hipoteza Śpiącej Królewny. Weryfikacja tej hipotezy wymaga zastosowania wielopoziomowych markerów starzenia się niesporczaków. Dlatego celem tej pracy doktorskiej było wskazanie potencjalnych markerów starzenia się niesporczaków. Aby osiągnąć ten cel, przeanalizowano dostępne publikacje pod względem możliwych markerów i opracowano odpowiedni model do ich eksperymentalnej walidacji, obejmujący samice i samce niesporczaka Paramacrobiotus experimentalis w różnym wieku. Wyniki pozwoliły na wskazanie następujących markerów starzenia się niesporczaków: żywotność, średnia liczba złożonych jaj przez samicę, przeżywalność warunków ekstremalnych (tj. anhydrobioza i pole hipomagnetyczne), poziom potencjału błony wewnętrznej mitochondriów (Δψ ) i poziom wewnątrzkomórkowych reaktywnych form tlenu (ROS). Weryfikacja przydatności wymienionych markerów może przyczynić się do wykorzystania niesporczaków także jako organizm modelowy w biologii starzenia. Wraz z weryfikacją hipotezy Śpiącej Królewny może to przyczynić się do opracowania strategii przeciwstarzeniowych i skutecznych rozwiązań dotyczących konserwacji materiałów biologicznych. Niemniej jednak uzyskane wyniki należy poddać dalszej weryfikacji w odniesieniu do innych dwupłciowych gatunków niesporczaków, co pozwoli na lepsze zrozumienie obserwowanych różnic międzypłciowych. It is assumed that aging is inevitable, irreversible, and progressive but available data indicate that tardigrade aging might be delayed by cryptobiosis. The possibility is addressed by the Sleeping Beauty hypothesis. However, the hypothesis verification requires multilevel markers of tardigrade aging. Therefore, the aim of the thesis was to indicate potential tardigrade aging markers. To implement the aim available relevant papers were searched for the putative markers and suitable tardigrade model comprising Paramacrobiotus experimentalis females and males of different age was developed for the markers validation. The results allowed for indication of the following tardigrade aging markers: the vitality rate, average number of laid eggs per female, survival of the extreme conditions (i.e., anhydrobiosis and hypomagnetic field), the level of the mitochondrial inner membrane potential (Δψ) and the level of intracellular reactive oxygen species (ROS). Verification of usability of the mentioned markers could open the opportunity for tardigrades to be also a model organism for aging biology. Together with verification of the Sleeping Beauty hypothesis, this might contribute to developing of anti-aging strategies and efficient approaches for preservation of biological materials. Nevertheless, the obtained results should be further verified for other dioecious tardigrade species which will allow for a better understanding of the observed differences between the sexes.Item Recovery from anhydrobiosis in the tardigrade Paramacrobiotus experimentalis: Better to be young than old and in a group than alone(Heliyon, 2024) Nagwani, Amit Kumar; Melosik, Iwona; Kaczmarek, Łukasz; Kmita, HannaDesiccation-tolerant organisms can survive dehydration in a state of anhydrobiosis. Tardigrades can recover from anhydrobiosis at any life stage and are considered among the toughest animals on Earth. However, the factors that influence recovery from anhydrobiosis are not well understood. The study aimed to evaluate the effect of sex, age, the presence of other individuals and the combination of the number and duration of anhydrobiosis episodes on the recovery of Paramacrobiotus experimentalis. The activity of 1200 individuals for up to 48 h after rehydration was evaluated using analysis of variance (ANOVA). Age was the main factor influencing return to activity, followed by the combination of number and duration of anhydrobiosis episodes, influence of the presence of other individuals, and sex. More individuals returned to activity after repeated short than repeated long anhydrobiosis episodes and older individuals were less likely to recover than younger individuals. In addition, when compared to single animals, the presence of other individuals resulted in higher number of active animals after dehydration and rehydration. The effect of sex was significant, but there was no general tendency for one sex to recover from anhydrobiosis better than the other one. The results contribute to a better understanding of the anhydrobiosis ability of Paramacrobiotus experimentalis and provide background for full explanation of molecular, cellular and environmental mechanisms of anhydrobiosis.Item The effect of hypomagnetic field on survival and mitochondrial functionality of active Paramacrobiotus experimentalis females and males of different age(Frontiers, 2023-09-08) Nagwani, Amit Kumar; Budka, Anna; Łacka, Agnieszka; Kaczmarek, Łukasz; Kmita, Hanna; Cesari, MicheleEven for tardigrades, often called the toughest animals on Earth, a hypomagnetic field (HMF) is an extreme environment. However, studies on the effect of HMF on tardigrades and other invertebrates are scarce. Mitochondria play an important role in an organism’s response to extreme conditions. The effect of HMF on the mitochondrial inner membrane potential (Δψ), a well-known marker of mitochondria functionality, shows that mitochondria are very sensitive to HMF. To measure the HMF effect on Paramacrobiotus experimentalis, we calculated the tardigrade survival rate and Δψ level after HMF treatments of different durations. We also estimated the relationship between the age and sex of the tardigrade and the HMF effect. We observed age- and sex-related differences in Δψ and found that Δψ changes after HMF treatment were dependent on its duration as well as the animal’s age and sex. Furthermore, active P. experimentalis individuals displayed a high survival rate after HMF treatment. The data may contribute to the understanding of tardigrade aging and their resistance to extreme conditions including HMF, which in turn may be useful for future space explorations.