696 research outputs found
Structural and Functional Organization of the Vestibular Apparatus in Rats Subjected to Weightlessness for 19.5 Days Aboard the Kosmos-782 Satellite
The vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days. The vestibular apparatus was removed and its sections were fixed in a glutaraldehyde solution for investigation by light and electron microscopes. Structural and functional charges were noted in the otolith portions of the ear, with the otolith particles clinging to the utricular receptor surface and with the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is possible that increased edema of the vestibular tissue resulted in the destruction of some receptor cells and in changes in the form and structure of the otolith. In the horizontal crista, the capula was separated
Predator-Induced Vertical Behavior of a Ctenophore
Although many studies have focused on Mnemiopsis leidyi predation, little is known about the role of this ctenophore as prey when abundant in native and invaded pelagic systems. We examined the response of the ctenophore M. leidyi to the predatory ctenophore Beroe ovata in an experiment in which the two species could potentially sense each other while being physically separated. On average, M. leidyi responded to the predator’s presence by increasing variability in swimming speeds and by lowering their vertical distribution. Such behavior may help explain field records of vertical migration, as well as stratified and near-bottom distributions of M. leidyi
Finding undetected protein associations in cell signaling by belief propagation
External information propagates in the cell mainly through signaling cascades
and transcriptional activation, allowing it to react to a wide spectrum of
environmental changes. High throughput experiments identify numerous molecular
components of such cascades that may, however, interact through unknown
partners. Some of them may be detected using data coming from the integration
of a protein-protein interaction network and mRNA expression profiles. This
inference problem can be mapped onto the problem of finding appropriate optimal
connected subgraphs of a network defined by these datasets. The optimization
procedure turns out to be computationally intractable in general. Here we
present a new distributed algorithm for this task, inspired from statistical
physics, and apply this scheme to alpha factor and drug perturbations data in
yeast. We identify the role of the COS8 protein, a member of a gene family of
previously unknown function, and validate the results by genetic experiments.
The algorithm we present is specially suited for very large datasets, can run
in parallel, and can be adapted to other problems in systems biology. On
renowned benchmarks it outperforms other algorithms in the field.Comment: 6 pages, 3 figures, 1 table, Supporting Informatio
DEVELOPMENT OF GLUTATHIONE-RESPONSIVE DISULFIDE-CONTAINING POLY(BETA-AMINO ESTERS) WITH VARIED HYDROPHILICITY AND ACRYLATE FUNCTIONALITY
Smart biomaterials are becoming promising for therapeutic deliveries due to their ability to respond to changes in the environment. Redox-responsive hydrogels are a promising type of smart polymer that can swell and degrade according to cellular oxidative stress levels. Glutathione, abundant in cells, is crucial in redox-responsive biomaterials, serving as a key reactive molecule. This study explored the degradation kinetics of glutathione-responsive poly(β-amino ester) (PBAE) polymers created through a single-step Michael addition. We examined how disulfide content influences the degradation kinetics of these PBAE networks. Additionally, we investigated how the hydrophilicity and functionality of acrylate affect the degradation of disulfide-containing PBAE systems. These redox-sensitive materials were tested under nearly physiological conditions of reduced glutathione to determine its effects on the swelling and degradation behavior of disulfide-containing PBAE polymers. Based on these findings, we developed disulfide-containing PBAE nanogels
Use of lipids of Chlorella microalgae in poultry meat marinades and sauces recipes
ArticleThe aim of this study is to develop formulations and technologies for fermented poultry
meat products with the addition of whey and lipid extracts obtained from Chlorella microalgae.
Lyophilized microalgal biomass was obtained from cell suspensions of Chlorella sorokiniana
(strain 211-8k) cultivated in a closed photobioreactor under laboratory conditions. For the cell
wall disintegration, the biomass samples were homogenized using a high-speed homogenizer at
10,000 vol min-1
for 5 minutes. The lipid extraction was performed on a Sohxlet apparatus Buchi
E-812 SOX with the solvent extraction system ethanol: n-hexane (1: 9). The higher fatty acids
composition of the obtained microalgal lipid extracts was determined by gas chromatography
with flame-ionization detection using nitrogen as a carrier gas. The ω-3 and ω-6 content
represented 26.59% and 19.05% respectively, which indicates that these lipid extracts have high
nutritional values. The curd whey was obtained from cow's milk of summer and winter production
from 2017 to 2018 (Lomonosov district auxiliary farm, Leningrad region); and lyophilized Direct
Vat Set (DVS) cultures (Ch. Hansen, Denmark). The organic acids and carbohydrate content in
the serum was determined by ion-exclusion HPLC. The FD-DVS CHN-19 culture was selected
to produce a serum with improved organoleptic characteristics and a lower propionic acid content
(0.01 g L
-1
). To obtain an optimal ω-3 / ω-6 ratio, a phyto-additive mixture based on sunflower
oil and lipid extracts from C. sorokiniana microalgae at a ratio of 5–10: 1 is proposed to be used
in recipes and technologies of sauces and marinades. It is established that the use of curd whey
marinades allow to increase the water-holding capacity (WHC) by 6−8% and to reduce losses
during heat treatment of poultry meat from 2 to 11%
Study of transhydrogenase systems features in the mutants of the yeast pachysolen tannophilus for the production of ethanol and xylitol from agricultural wastes
The key catabolic enzymes of D-xylose, an important structural component of different
agricultural wastes, were studied in cells of mutant strains of the xylose-assimilating yeast
Pachysolen tannophilus. The evaluation of catalytic activity and cofactor specificity of xylose
reductase (ЕС 1.1.1.307) and xylitol dehydrogenase (ЕС 1.1.1.9) confirmed the dependence of
intracellular catabolic pathway for D-xy lose on the NAD×H/NADP×H ratio, formed under
microaerobic conditions. The study of total activity of some NAD+
/NAP×H-dependent
dehydrogenases revealed the metabolic characteristics of the yeast cells, which could ensure
selective ethanol or xylitol production. Thus, the efficient involvement of D-xylose into the
Embden–Meyerhof–Parnas pathway provided not only the high activities of xylose reductase and
xylitol dehydrogenase, but also of 1-glycerophosphate dehydrogenase (EC 1.1.1.8) and lactate
dehydrogenase (ЕС 1.1.1.27), respectively. The inhibition of activity of these enzymes led to
selective production of xylitol from D-xylose. On the base of the experimental results, the
principles of metabolic engineering of xylose-assimilating yeasts were formulated. The
possibility of bioethanol and xylitol production from different agricultural wastes using xyloseassimilating yeasts are discussed
Combinatorial Investigation of Magnetic Materials
Combinatorial synthesis is an efficient tool that can be used to discover new materials. It allows one to systemically study a large number of materials simultaneously as their physical properties change with the varying chemical composition. Using this technique, we study various multifunctional electronic materials. Different designs of libraries, such as discrete libraries and composition spreads, are fabricated and characterized in order to rapidly map composition-structure-property relationships in a variety of systems.
We have made gas sensor device libraries to optimize the performance of gas sensing materials. We have utilized the combinatorial pulsed laser deposition (PLD) flange for fabricating the discrete device library of doped SnO2 thin films. Several libraries were made with different amounts of dopants such as In2O3, WO3, ZnO, Pt, and Pd. After exposing the whole library to chloroform, formaldehyde, and benzene gases, the compositions most sensitive to these gases were found. We have also demonstrated the use of a gas sensor library as an electronic nose where responses from different devices are multiplexed to perform pattern recognition for distinguishing different gases at concentrations down to 12.5 ppm with high repeatability of response signals.
Magnetic properties of composition spreads and discrete libraries are analyzed by a scanning SQUID microscope. The in-plane and out-of-plane magnetization distributions are calculated from the magnetic field data using the inversion technique. Various parameters that control the inversion technique are discussed in detail and optimized with the help of simulated data.
By applying the inversion technique to thin-film discrete libraries, we have mapped the functional phase diagram of Ni-Mn-Ga system whose Heusler composition Ni2MnGa is a well known ferromagnetic shape memory alloys (FSMAs). A large, previously unexplored compositional region of FSMAs outside the Heusler composition is found.
In search for novel multiferroic materials, we have fabricated PbTiO3 (PTO)-CoFe2O4 (CFO) composition spreads using the combinatorial PLD. After calculating the in-plane and out-of-plane remanent magnetization distributions with the help of the inversion technique, it was found that when PTO is added to CFO, CFO's magnetic anisotropy changes. Furthermore, we found that the compositional region between (PTO)0.5(CFO)0.5 and (PTO)0.8(CFO)0.2 exhibits the coexistence of ferroelectricity and ferromagnetism
A method for obtaining plastid pigments from the biomass of Chlorella microalgae
Microalgae are distinguished from land plants by the high content of plastid pigments
and the biodiversity of carotenoids. The aim of this study is to develop a technology for extracting
a pigment complex from the biomass of the microalgae of the genus Chlorella and to determine
the extracted pigments’ composition. To obtain biomass, a crude cell suspension of microalgae
was used, which was obtained under laboratory conditions for pre-culture cultivation of
C. sorokiniana (strain 211-8k). The extraction of plastid pigments from air-dry biomass after
disintegration of cell membrane was performed in the 40 kHz mode. It was found that the highest
pigment content in ethanol extracts was observed after 30 min (870.0 ± 27.1 mg L
-1
) at 45−50 °C.
The pigments’ composition in the resulting total extracts was determined by spectrophotometry
and the Reverse Phase HPLC method. The established content of chlorophyll a in the obtained
extracts was 537.5 ± 10.0 mg L
-1
, the content of chlorophyll b was 182.5 ± 27.5 mg L
-1
; the
maximum output of the amount of carotenoids in extracts was 150.0 ± 10.0 mg L
-1
. Thus, the
main identified forms of carotenoids in extracts from the biomass of microalgae C. sorokiniana
were xanthophylls: lutein and fucoxanthin (18.6 and 4.7% of the amount of pigment in extract,
respectively) and β-carotene (1.8% of the amount of pigment). It is planned to further fractionate
the obtained total extracts of the pigment complex to obtain various forms of chlorophylls and
carotenoids to study the spectrum of physiological activity of plastid pigments
Characteristics of contralateral carcinomas in patients with differentiated thyroid cancer larger than 1 cm
Purpose: Traditionally, total thyroidectomy has been advocated for patients with tumors larger than 1 cm. However, according to the ATA and NCCN guidelines (2015, USA), patients with tumors up to 4 cm are now eligible for lobectomy. A rationale for adhering to total thyroidectomy might be the presence of contralateral carcinomas. The purpose of this study was to describe the characteristics of contralateral carcinomas in patients with differentiated thyroid cancer (DTC) larger than 1 cm. Methods: A retrospective study was performed including patients from 17 centers in 5 countries. Adults diagnosed with DTC stage T1b-T3 N0-1a M0 who all underwent a total thyroidectomy were included. The primary endpoint was the presence of a contralateral carcinoma. Results: A total of 1
Antirheumatic drugs and COVID-19: frustrations and hopes
In accordance with current views on the pathogenesis of the new coronavirus infection, some antirheumatic drugs are considered as therapeutic agents for suppressing the hyperinflammatory response in severe COVID-19. The review presents literature data on the efficacy and safety of certain basic anti-inflammatory and genetically engineered drugs in patients with COVID-19. Hydroxychloroquine is not indicated for the treatment of SARS-CoV-2 infection of any severity due to the lack of therapeutic benefits, the likelihood of a worse prognosis in more severe patients and the development of adverse reactions, especially when used concomitantly with azithromycin. The use of systemic glucocorticoids (GC) in patients with COVID-19 who require oxygen support leads to a decrease in mortality and an improvement in the prognosis of the disease. However, the optimal time of administration, dose and duration of HA administration remain the subject of further research. Despite the encouraging data, it is too early to draw final conclusions about the feasibility of using tocilizumab in COVID-19, since no randomized clinical trials have demonstrated a clear advantage of the drug in terms of reducing mortality. The use of anakinra does not reduce the need for noninvasive / invasive lung ventilation or the mortality of patients with COVID-19. Two drugs from the group of tumor necrosis factor inhibitors - infliximab and adalimumabare currently being considered as possible treatment options for COVID-19. The use of a combination of baricitinib and remdesivir for the treatment of COVID-19 patients requiring oxygen support has been approved. New RCTs are needed to study the effectiveness of other anti-rheumatic drugs in COVID-19
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