Doklady Biological Sciences最新文献

Tissues and mucus of acorn worms are known to contain phenolic compounds, which inhibit activity of aerobic bacteria. Mycobiota of tissues, the body surface, and burrows were studied for the acorn worm Saccoglossus mereschkowskii (Wagner, 1885). Three fungal species were found in the plating of intestine samples. Seven fungi were isolated from samples washed out from the S. mereschkowskii body surface. Five species were found in burrow samples; and 15, in sediment samples from the S. mereschkowskii habitat. Cultures of intact specimens, gill bars, and axial organ did not reveal the growth of mycelial fungi. A potential fungistatic effect was consequently assumed for acorn worm tissues.

The microstructure of hairs from several parts of the body of a three-week-old cub of Pleistocene Homotherium latidens was for the first time studied using light microscopy and scanning electron microscopy (SEM). The frozen H. latidens mummy dated to 31 808-37 019 years ago was found in Yakutia and first described by Russian paleontologists. The H. latidens mummy was shown to have poorly differentiated short uniform tangled dark-brown hair. Hairs had rather poor heat-protective properties because of the weak development of the hair medulla, while their mechanical strength was excellent. The hair microstructure varied depending on the hair location on the body. The findings were compared with data on the hair of cave and African lion cubs. Similarities and differences in microstructure were observed for the species and were explained from the functional viewpoint.

Exogenous 24-epibrassinolide (EBL) and a synthetic EBL-based conjugate (2,3,22,23-tetraester of EBL and succinic acid) used at 10 nM were for the first time shown to almost equally mitigate the negative effects of salt stress (150 mM NaCl) on rapeseed plants, sustaining their photosynthetic activity and growth parameters. Specificity was observed in the action of the compounds in regulating the NaCl resistance of rapeseed plants. EBL increased the content of carotenoids and superoxide dismutase and peroxidase activities in plants exposed to chloride salinization, while the EBL conjugate increased peroxidase activity only. Pretreatment of plants for 4 h before stress exposure was more efficient than treatment applied simultaneously with stress.

The regenerative potential of platelet-rich plasma (PRP) samples from patients with type 1 diabetes mellitus (DM) was studied in vitro. In a series of experiments, PRP was added to the culture medium of human dermal fibroblasts. The cells were tested for metabolic (including reactive oxygen species production), migration, and proliferative activities at several time points; growth factors and exosome levels were assessed in PRP and the medium. A lower proliferative effect, pro-oxidant properties, and toxicity were observed for PRPs from diabetic patients. Namely, treated fibroblasts showed lower metabolic activity, a lower cell viability, and a greater percentage of necrosis in culture, while their migration properties were not impaired. PRPs from diabetic patients exerted a lower stimulatory effect on growth factor secretion by dermal fibroblasts. PRPs from elderly diabetics had the greatest effects.

The shell wall ultrastructure is known for three of the four classes of multicameral Foraminifera with a secretive calcareous shell wall: Rotaliata Mikhalevich, 1980; Miliolata Saidova, 1981; and Nodosariata Mikhalevich, 1992. It was believed that one or few large crystals form the wall in Spirillinata Mikhalevich, 1992. The study showed that the entire shell is formed of amorphous, rather than crystalline, CaCO₃ in Raskiniella plana (previously classified as Spirillina plana Wiesner, 1931), which is a typical representative of this class. Amorphous calcareous skeletons are known in certain unicellular algae and multicellular eukaryotes, a skeleton of the entire adult shell completely build of amorphous CaCO₃ was observed for the first time in Foraminifera.

Genetic diversity of neutral markers (15 microsatellite loci) was assessed for the first time in two landlocked seal species, the Baikal seal Pusa sibirica and Caspian seal P. caspica, and compared with that in the oceanic species ringed seal P. hispida of the same genus. Lower genetic diversity was observed in both of the landlocked seal species, the Baikal seal having the lowest level. A high probability of a historical bottleneck effect was shown for both Baikal and Caspian seals, while signs of a sharp decline in the past were not observed in the ringed seal population. A data analysis with the VarEff package suggested different times to the most recent common ancestor (TMRCA) for each of the three populations. The time established for the Baikal seal was significantly shorter than that of the Caspian seal.

Characteristic patterns of UV-induced skin autofluorescence were determined for patients with Parkinson's disease (PD) and associated with dysmetabolic alterations, such as nonenzymatic protein glycation, an increase in extracellular matrix stiffness, impaired metabolism of tissue fluorophores, mitochondrial dysfunction, and accumulation of aberrant proteins. Key differences in skin autofluorescence spectra were for the first time observed in PD, making it possible to discriminate between PD patients and healthy persons or individuals without signs of chronic neurodegeneration. Namely, skin fluorescence related to the reflected signal upon excitation with UV light at 375 nm was lower in PD patients.

Aquaculture is one of the main sources of fish products and ensures their sustainable growth on the global scale, exceeding industrial fishing. At the same time, integrated processing of aquaculture by-products is an important environmental and industrial problem. Valuable biological components might be found in fish processing wastes left after manufacturing the target products (fillet, offal, etc.). In particular, antimicrobial peptides that exhibit broad-spectrum antimicrobial activity are expressed in fish. A first exploratory analysis of rainbow trout Oncorhynchus mykiss brain proteins was performed to identify the theoretical antimicrobial patterns. More than half of the identified proteins were predicted to have antimicrobial regions. The proteins included histones, vitellogenin, collagen, etc. The results may be of interest for designing drugs based on peptides active against various pathogens. The field is of importance in view of the increasing antibiotic resistance of pathogenic microorganisms.

Primary drug resistance of tumor cells or resistance acquired during treatment is among the main factors that significantly limit the efficacy of antitumor chemotherapy, along with severe side effects depending on the drug dose. To increase the efficacy, chemotherapeutics can be used in combination with substances that modulate the functions of cell signaling pathways. In this work, the substance XMU-MP-1, an inhibitor of key MST1/2 kinases of the Hippo signaling pathway, was shown to enhance the antitumor activity of two genotoxic chemotherapeutics, etoposide and cisplatin, against Namalwa Burkitt's B-cell lymphoma cells. XMU-MP-1 increased the cytotoxicity of the agents and significantly reduced their CTD₅₀. The drug efficacy is therefore possible to increase significantly, and a therapeutic effect might be achieved at a lower drug concentration to reduce the likelihood of life-threatening side effects.

The type of development is known to correlate with the egg size in marine invertebrates. Data on the maximum oocyte size were considered for deep-sea acorn worms of the family Torquaratoridae. The family was assumed to include species with direct development, species with lecithotrophic larvae, and species with planktotrophic larvae. Mysterious giant larvae of Planctosphaera pelagica may be planktotrophic larvae of Torquaratoridae.