Uspehi sovremennoj biologii

Mitochondria are an important source of reactive oxygen species in skeletal muscle. Mitochondrial dysfunction accompanies the development of age-related human diseases. Increased production of reactive oxygen species contributes to muscle atrophy caused, for example, by physical inactivity. Many regulatory pathways involved in mitochondrial biogenesis are targets of anti-aging therapies. Active lifestyle and exercise prevent age-related damage to skeletal muscle mitochondria. Another way to correct the action of reactive oxygen species is the use of antioxidants directly targeted to the mitochondria. Treatment with mitochondria-targeted antioxidants attenuates mitochondrial degeneration, improves age-related skeletal muscle function, and protects muscles from atrophy. This review presents data on the use of mitochondrial-directed antioxidants and exercise to maintain the structural and functional state of mitochondria, and protect muscles from sarcopenia.

When considering the pathogenesis of COVID-19 and post-Covid syndrome, disorders associated with the immune system come to the fore. Complexes of immune dysregulation, dissonant reactions of the patient’s innate and adaptive immune systems, should be considered the main causes of the complex pattern of lesions. These processes include cellular inflammation, disorder of hemovascular homeostasis, and organ damages. Consistent analysis of these processes serves as the basis for choosing therapeutic strategy schemes, taking into account clinical indicators and personal characteristics of patients.

Monochorionic diamniotic twin gestations have a higher risk of perinatal complications than both dichorionic twins and singleton pregnancies. One of the complications of multiple pregnancies is selective fetal growth restriction (sFGR), the incidence of which varies from 10 to 25%. sFGR is a condition of twin pregnancy in which the development of one fetus is restricted, despite normal growth of the other fetus; one of the fetuses is supplied with insufficient nutrient and oxygen content through the placenta to grow at a normal rate. The pathogenesis of sFGR has a multifactorial nature, including disorders of trophoblast invasion, vasculo- and angiogenesis, gestational formation of the placenta with discordant separation of intertwin territories and unbalanced blood flow through interfetal anastomoses oxidative stress, growth factor imbalance, and changes in the metabolomic profile of cord blood and placental tissue. The prenatal diagnosis of sFGR is sometimes problematic and it is not possible to find all the cases. A more detailed study of the various predictors of the occurrence of sFGR will allow the discovery of new markers that will help in early diagnosis, determining the optimal management for pregnancy and predicting perinatal outcome.

We calculated the found and expected frequencies of metacentrics in polymorphic populations of the Dnieper basin common rodent, resulting from hybridization of local populations with acrocentric karyotype and four chromosomal races (Neroosa, Kiev, Białowieża, and Western Dvina) with 3–5 diagnostic metacentrics in each. We have previously shown an increased frequency of acrocentric karyotype compared to that expected according to Hardy-Weinberg. The low frequency (less than 0.5) of most metacentrics of the four chromosomal races and the disappearance of some of them from the populations can be explained by the increased fitness of the acrocentric karyotype and the absence of meiotic drive. On the contrary, the preservation of high frequency (more than 0.5) of such metacentrics as gm, hk (races of Western Dvina), hi (races of Kiev), hn, ik (races of Białowieża), and, especially, the fixation of metacentric hi (races of Neroosa) in polymorphic populations can be explained by meiotic drive. The fixation of Rb compounds in the range of the common rodent may be a consequence not only of gene drift, but also of meiotic drive. Most likely, meiotic drive is able to maintain the frequency of Rb compounds with the largest acrocentrics g, h, and i, which contributed to the widespread distribution of such compounds throughout the range of the common rodent.

An audit of the marine and freshwater ichthyofauna of the Arctic has been carried out. According to new data, the ichthyofauna of the Arctic is represented by 4 classes, 33 orders, 103 families, 251 genera and 479 species of cyclostomes and fish (or about 1% of the world fauna), of which 214 species or 45% of the number of species in the Arctic are true Arctic species. Arctic fish are characterized by polymorphism and euryphagy, which are associated with the variable and low food supply of northern water bodies. The ichthyofauna of the Arctic is well represented by taxa with a wide adaptive radiation (genera Coregonus, Salvelinus, Lycodes, etc.) and species with a complex intraspecific structure such as superspecies or species-complex. Another characteristic feature of the Arctic is low endemism of ichthyofauna at the level of families (5%), genera (2%) and species (10%). Possible routes of distribution of whitefish and pike in the water bodies of the North have been discussed.