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Silicon nitride membranes were experimentally obtained as substrates for biological samples, which are examined using a microscope with an operating wavelength of 13.8 nm. The free-hanging films obtained have a size of up to 1.5 × 1.5 mm2, which makes it possible to select an area of interest for investigation on the sample on the order of tens to hundreds of microns. The mechanical strength of the membranes satisfies that the samples do not tear the membranes and withstand transportation. The results obtained are an import-substituting technology for the manufacture of Si3N4 membranes. The resulting membranes have a transparency of more than 40% in the range of the "water transparency window" (2.3–4.4 nm) and EUV (13–15 nm). The developed technology will become the basis for creating cuvettes for living biological samples for soft X-ray microscopy studies. [ABSTRACT FROM AUTHOR]

For soft X-ray microscopy in the approximation of geometrical optics, a theoretical model for the formation of the received image is constructed – a relationship is found between the image recorded on the detector and the 3D distribution of the sample absorption index using a high-aperture mirror objective (NA ¿ 0.3) with a focus depth close to the diffraction limit. The solution of the inverse problem of tomography for determining this 3D distribution from the data of measurements in a high-aperture mirror SXR-microscope is obtained. [ABSTRACT FROM AUTHOR]

The two Manila clam forms living in the Sea of Japan and in the Adriatic Sea were compared genetically and morphologically to identify traits that could be used to authenticate these geographic forms. COX1 DNA barcoding confirmed that both forms of these venerid bivalve belong to the species Ruditapes philippinarum (Adams and Reeve, 1850). It has also been shown that, based on COX1 analysis, it is not possible to separate these forms into different clusters based on geographic origin. However, some morphological features make it possible to differentiate these forms. It is noted that the contour of the shells of the Adriatic and Pacific molluscs is rounded and oblong, respectively. Underwater analysis of Pacific clams showed that shell color may be specific to specimens found at certain collection sites and differ between specimens taken from different collection sites. In the spermatogenesis of Adriatic and Pacific clams, a difference was found in the cellular mechanism of interaction between germplasm granules and mitochondria, manifested by distant contact and direct contact. Spermiogenesis has three similar lines of acrosome development, but differs in the number of ways in which the nucleus is formed. Due to the variability of the ways of sperm formation, heteromorphic morphs of spermatozoa are formed, the total number of which is six for the species R. philippinarum. In the Adriatic Manila clam, five morphs from this set are expressed. The Pacific Manila clam has only three sperm morphs. Only two sperm morphs are similar in both forms. In addition, each form is distinguished by the presence of unique sperm morphs and each form has its own type of dominant spermatozoon. Thus, the contour and color of the shells, as well as cytologic markers that have been found in the mechanisms of differentiation of meiotic cells and the characteristics of spermatozoa, can be used to distinguish the Adriatic and Pacific forms of the bivalve mollusc R. philippinarum. [ABSTRACT FROM AUTHOR]

In this paper, the size and intensity of laser-plasma sources based on pulsed argon gas jets operating at a wavelength of 13.84 nm are studied. The gas jet is excited by laser radiation at a wavelength of 1064 nm with a pulse duration of 4.4 ns, a repetition frequency of 10 Hz, and a pulse energy of 0.5 J. Two methods are used to form the jet of a pulsed gas target: using a jet with a supersonic nozzle and using a capillary. The capillary source is commercially available. The sources are certified using a mirror microscope operating in the extreme ultraviolet region at a wavelength of 13.84 nm. Due to the possibility of supplying a higher pressure of the operating gas to the nozzle inlet, increasing the density, and reducing the exit angle of the gas jet in the supersonic nozzle compared to the capillary, the peak radiation intensity at a wavelength of 13.84 nm is found to increase six times. The width at half maximum of the injector-based source diameter is 250 ± 10 μm with a profile close to Gaussian. In the field of view of a microscope of 25 × 25 μm, the nonuniformity of illumination from the "source on the injector" is ~1%, and in the field of view of 50 × 50 μm, it is ~4%. The width at half maximum of the source diameter based on a commercial valve with a capillary source is 330 ± 10 µm with a profile close to U-shaped. Based on the results of the comparison, an upgraded version of the microscope with up to 350× magnification will use an injector-based source. [ABSTRACT FROM AUTHOR]

A brief description of the concept of a soft X-ray microscope for the Nanoscope station, which is planned to be installed at the SKIF fourth-generation synchrotron, is given. The microscope is designed to study the structure of cells and dynamic processes in them with nanometer spatial resolution. It will use a unique absorption contrast of ~15 between carbon-containing structures and water in the spectral range of the water window, λ = 2.3–4.3 nm, which eliminates the need for contrasting and the use of fluorophores and minimizes the doses of ionizing radiation absorbed in the samples to obtain high-quality 3D images. The scanning and projection schemes of the microscope, their main technical characteristics, including the calculated spectra and parameters of the undulator source are presented, and an estimate of the absorbed doses depending on the resolution is obtained. The main advantage of the proposed concept lies in the use of an objective lens of high-aperture multilayer X-ray mirrors, which makes it possible to clearly visualize the focal section of the sample. Technically simple axial tomography will also be used to reconstruct the three-dimensional structure of frozen or dried samples. In the scanning scheme, due to a low dose of radiation, it will be possible to study living plant cells with a resolution of up to 10 nm, animals with a resolution of up to 80 nm, and cryofixed samples with a resolution of up to 5 nm. In the projection scheme, due to simultaneous observation of the entire focal XY section, the time for obtaining three-dimensional images is significantly reduced, but due to a large dose, it will be oriented mainly on the study of fixed samples. [ABSTRACT FROM AUTHOR]

In this paper, selection of the optimal filtering method and variations in its parameters are carried out to improve the image quality without losing the useful signal. A new image-filtering method that does not lead to the blurring of images is proposed to remove noise. The appearance of noise is associated with heating of the recording system of the specular "soft" X-ray microscope. At the moment, there are a vast number of methods and algorithms for removing noise from an image. However, most the methods blur the original image because of filtering according to the filter kernel. This blurring leads to a deterioration in the resolution or even to the loss of some useful information, which can play an important role in the processing of experimental images. A combined image-filtering method that includes a threshold filter and a median one is proposed. This combination allows one to initially find local jumps or dips of the signal (the range of which is set manually), which will later be replaced by median values of the vicinity of a point in the image. As a result, the median filter is not applied to the entire image, but only where there are sharp differences in the intensity, so it does not blur the image as a whole. [ABSTRACT FROM AUTHOR]

To analyze the release of mitochondrial material, a process that is believed to be (i) induced by the VASA protein derived from germplasm granules, and (ii) which appears to play an important role during meiotic differentiation, the localization of the CYTB protein was studied in the process of spermatogenesis of the bivalve mollusk Ruditapes philippinarum (Manila clam). It was found that in early spermatogenic cells, such as spermatogonia and spermatocytes, the CYTB protein shows dispersion in the cytoplasm following the total disaggregation of VASA-invaded mitochondria, what is called here as "destructive mitochondrial effusion (DME)." It was found that the mitochondria of the maturing sperm cells also uptake VASA. It is accompanied by extramitochondrial transmembrane localization of CYTB assuming mitochondrial content release without mitochondrion demolishing. This phenomenon is called here as "nondestructive mitochondrial effusion (NDME)." Thus, in the spermatogenesis of the Manila clam, two patterns of mitochondrial release, DME and NDME, were found, which function, respectively, in early spermatogenic cells and in maturing spermatozoa. Despite the morphological difference, it is assumed that both DME and NDME have a similar functional nature. In both cases, the intramitochondrial localization of VASA coincides with the extramitochondrial localization of the mitochondrial matrix. [ABSTRACT FROM AUTHOR]

An integrated microscopic study of the destruction of mouse Ehrlich ascites carcinoma (EAC) cells under starvation conditions has been carried out. It has been found that, in addition to apoptosis, necrosis, and apoptotic necrosis, already known for EAC, cell destruction can also occur through mitochondrial autolysis, which is proposed to be considered a new kind of mitoptosis. A mitoptosis in EAC is characterized by the appearance of many autolyzing mitochondria, the fusion of which leads to rupture of the cell membrane and the ejection of the nucleus from the cell. It is assumed that the polymorphism of EAC destruction patterns is explained by the different physiological state of the cells, which determines the "choice" of the cell death mechanism. This situation poses a challenge for researchers to develop complex inducers with the ability to stimulate all possible types of cancer cell death. [ABSTRACT FROM AUTHOR]

In this study, we investigated in an androgenized rat model the involvement of autophagy and mitochondrial dynamics in granulosa cells in the pathogenesis of polycystic ovarian syndrome (PCOS) and its modulation by exogenous gonadotropin (eCG). We found 5α-dihydrotestosterone (DHT) treatment reduces ovarian length and weight with predominantly late antral and/or preovulatory stage follicles and no corpora lutea. DHT increased the population of large lysosomes (>50 micron) and macroautophagy, an event associated with granulosa cell apoptosis. Increased granulosa cell Dynamin Related Protein 1 (Drp1) content in the DHT group was accompanied by increased circular and constricted, but reduced rod-shaped, mitochondria. eCG eliminated all atypical follicles and increased the number of late antral and preovulatory follicles with less granulosa cell apoptosis. eCG-treated rats had a higher proportion of connected mitochondria, and in combination with DHT had a lower proportion of circular and constricted mitochondria than rats treated with DHT alone, suggesting that eCG induces mitochondrial fusion and attenuates fission in granulosa cells. In summary, we observed that DHT-induced up-regulation of Drp1 is associated with excessive mitochondrial fission, macroautophagy and apoptosis in granulosa cells at the antral stage of development in an androgenized rat model for PCOS, a response partially attenuated by exogenous gonadotropin. [ABSTRACT FROM AUTHOR]

The mode of the growth of InGaAs quantum dots by MOS-hydride epitaxy on GaAs substrates without a deviation and with a deviation of 2° is selected for laser structures emitting at wavelengths above 1.2 μm at room temperature. As a result, a quantum-dot density of 4 × 1010 cm–2 is achieved. Stimulated emission is observed in laser structures with seven layers of quantum dots at a wavelength of 1.06 μm at liquid-nitrogen temperature. The threshold power density of optical pumping is about 5 kW/cm2. [ABSTRACT FROM AUTHOR]

The properties of InGaAs/GaAs quantum dots (QDs) grown by MOS-hydride migration-stimulated epitaxy at a reduced pressure using submonolayer deposition are investigated. The wavelength of their photoluminescence at 300 K is in the range of 1.28–1.31 μm and can be controlled by varying the growth temperature and the number of QD-deposition cycles. The highest QD surface density is 3 × 1010 cm–2. Structures with 1–3 QD layers and spacer layers 5–12 nm thick between them are grown. The spacer layers (as well as the cap layers) are selectively doped with carbon (acceptor). It is established that the QD photoluminescence is characterized by an enhanced degree of polarization in the direction orthogonal to the structure plane. This should favor their use for the excitation of surface plasmon–polaritons in Schottky light-emitting diodes. [ABSTRACT FROM AUTHOR]

Abstract: Stressed InGaAs/GaAs quantum-well laser structures are grown by gas-phase epitaxy from organometallic compounds on GaAs substrates and artificial Ge/Si substrates based on Si(001) with an epitaxial metamorphic Ge layer. To suppress the relaxation of elastic stresses during the growth of InGaAs quantum wells with a high fraction of In, strain-compensating GaAsP layers are applied. The structural and radiative properties of the samples grown on substrates of various types are compared. Stimulated radiation at wavelengths up to 1.24 μm at 300 K is obtained for structures grown on GaAs substrates and at wavelengths up to 1.1 μm at 77 K, for structures grown on Ge/Si substrates. [ABSTRACT FROM AUTHOR]

It was shown that tobacco leaf treatment with 100 mM HO increased their content of endogenous HO and activities of catalase and hydrolases (acid phosphatase, proteases, and RNase) and also caused various changes in the cell structure. In this case, programmed cell death (PCD) occurred in some cells, which was observed as chromatin condensation, cytoplasm collapse, etc. In the meantime, many cells displayed organelle activation rather than PCD. It is suggested that cells that undergo HO-dependent PCD release signaling molecules inducing protective mechanisms against oxidative stress in neighboring cells not exhibiting PCD. [ABSTRACT FROM AUTHOR]

The present work reveals the effect of kappa-, lambda- and kappa/beta-carrageenans on the immune modulation and supramolecular structure of lipopolysaccharide (LPS). The kappa/beta carrageenan was able to increase the synthesis of anti-inflammatory interleukin-10 (IL-10) in vitro, and at low concentrations, their activity in the mixture with LPS was higher than that of LPS alone. Kappa-carrageenan significantly inhibited LPS-induced upregulation of reactive oxygen species (ROS). The activation of cells by kappa-carrageenan occurs through TLR4 receptor specific for LPS. Carrageenans reduced (kappa-) or completely inhibited (lambda-) collagen-induced platelet aggregation and decreased their aggregation activity caused by cooperative effect of LPS and collagen. The transformation of ultrastructure of LPS by action of kappa- and kappa/beta-carrageenans is observed. Moreover, carrageenans changed both the sizes and ζ- potentials of the LPS. [ABSTRACT FROM AUTHOR]

Formation of germinal granules during oogenesis was studied in sea cucumbers, Apostichopus japonicus, Selenka, 1867, using transmission electron microscopy. It was found that within the early oogenesis mitochondria interact with a Balbiani body, gradually become immersed into its substance and transformed into electron-dense structures, which are similar to the germinal granules of metazoans. In late oogenesis, formed germinal granules lose their contacts with a Balbiani body and are localized in the cortical portion of the oocyte, near the cell membrane. Vestigial mitochondrial cristae are a typical feature of germinal granules. The obtained data suggest that the process of transformation of mitochondria into germinal granules is one of the functions of the Balbiani body, whose role still remains unexplained. [ABSTRACT FROM AUTHOR]

The effect of 20 cyclopentane β,β′-triketones and their sodium salts on the development of infections caused by tobacco mosaic virus (TMV) in leaves of tobacco ( Nicotiana tabacum L. cv. Xanthi-nc) has been studied. It has been shown that the strongest antiviral effect is produced by sodium salts of 2-acetyl-4,7-dithio-2,3,4,5,6,7-hexahydro-1 H-inden-1,3-dione, 2-acetyl-4-oxa-7-thio-2,3,4,5,6,7-hexahydro-1 H-inden-1,3-dione, and 2-acetyl-4,5-didodecylthiocyclopent-4-en-1,3-dione. These compounds at a concentration of 2 mg/mL decrease the number of local TMV-induced necroses formed on inoculated tobacco leaves by 98% and have no toxic effect on leaf tissues. [ABSTRACT FROM AUTHOR]

Modern ideas on the biogenesis of plant peroxisomes, their involvement in the production and detoxification of reactive oxygen species, and the role in the processes they mediate are discussed. The data on the proliferation and degradation of these organelles in the cell during the oxidative stress and on their involvement in the generation of signaling molecules are considered. [ABSTRACT FROM AUTHOR]

The mesophyll ultrastructure and hydrolase activity in leaves of tobacco cv. Samsun exposed to chitosan were studied. It was shown that, in many cells, chitosan treatment stimulated the protein-synthesizing apparatus (nucleolus size and amount of both mitochondria and membranes of rough endoplasmic reticulum increased). At the same time, we observed activation of the lytic compartment displayed as stimulated production of dictyosomes, smooth ER elements, and cytoplasmic vacuoles, which are prominent constituents of this compartment. Biochemical experiments showed that, in the leaves, chitosan substantially enhanced activity of hydrolases (acid phosphatase, RNase, proteases) as compared to untreated leaves. In some cells, chitosan treatment caused considerable destructive changes (condensation of nuclear chromatin, collapse of cytoplasm, etc.) that can be classified as development of programmed cell death. [ABSTRACT FROM AUTHOR]

A number of low molecular weight (LMW) fractions of carrageenans with different structural types were obtained by free radical depolymerization (HO), mild acid hydrolysis (HCl), and a specific enzyme. Three samples of carrageenans were depolymerized: kappa-carrageenan from Chondrus armatus, kappa-carrageenan from Kappaphycus alvarezii, and kappa/beta-carrageenan from Tichocarpus crinitus with initial molecular weights of 250, 390, and 400 kDa, respectively. The chemical depolymerization by two methods resulted to LMW derivatives of carrageenans with molecular weight from 1.2 to 3.5 kDa. Oligosaccharides of kappa- and kappa/beta-carrageenans with molecular weight of 2.2 and 4.3 kDa, respectively, were obtained after enzymatic depolymerization by recombinant kappa-carrageenase from Pseudoalteromonas carrageenovora. It was shown that the antiviral activity of high molecular weight carrageenans against tobacco mosaic virus was higher than that of their LWM derivatives independently on the depolymerization method. The method of depolymerization had some influence on the antiviral activity of carrageenan. LMW derivatives of kappa- and kappa/beta-carrageenans obtained by mild acid hydrolysis showed higher antiviral activity than the products of free radical depolymerization. The oligosaccharides prepared by enzymatic degradation possessed the lowest activity. [ABSTRACT FROM AUTHOR]

The activity of hydrolases (protease, RNase) in uninfected and tobacco mosaic virus-infected tobacco leaves of the Samsun variety, untreated and treated with disodium salt of 2-acetyl-4-hydroxycarbonyl-methylthio-5-chlorocyclopent-4-en-1,3-dione (DS), was determined. It was shown that treatment of leaves with this compound significantly increased the activity of hydrolases in them compared to untreated leaves. In infected leaves treated with DS one day before infection, along with an increased level of hydrolases, one revealed more viral particles exposed to destructive changes in infected, rather than untreated, leaves. It is assumed that the DS-caused activation of hydrolases promotes the destruction of viral particles and is therefore one of the cell defense mechanisms induced by this compound that prevents the intracellular accumulation of virus. [ABSTRACT FROM AUTHOR]

The state and management of the process of metrological assurance on the stage of design of the creation of Gazprom facilities are considered. Modern means and methods of measurement of parameters in the course of transport and distribution of gas as well as procedures involved in verification and calibration of parameters in accordance with the principle of assurance of the uniformity of measurements are presented . [ABSTRACT FROM AUTHOR]

We have previously shown that VegT mRNA plays a structural (translation-independent) role in the organization of the cytokeratin cytoskeleton in Xenopus oocytes. The depletion of VegT mRNA causes the fragmentation of the cytokeratin network in the vegetal cortex of Xenopus oocytes. This effect can be rescued by the injection of synthetic VegT RNA into the oocyte. Here, we show that the structural function of VegT mRNA in Xenopus oocyte depends on its combinatory signals for the induction or facilitation and for the maintenance of the depolymerization vs. polymerization status of cytokeratin filaments and that the 300-nucleotide fragment of VegT RNA isolated from the context of the entire molecule induces and maintains the depolymerization of cytokeratin filaments when injected into Xenopus oocytes. A computational analysis of three homologous Xenopus VegT mRNAs has revealed the presence, within this 300-nucleotide region, of a conserved base-pairing (hairpin) configuration that might function in RNA/protein interactions. [ABSTRACT FROM AUTHOR]

The activities of hydrolases (acid phosphatase, RNase, and proteases) in healthy and tobacco mosaic virus-infected leaves of Nicotiana tabacum L. var. Samsun, both untreated and treated with polysaccharides (PS) (1,3;1,6-β-D-glucan, fucoidan, and κ/β-carrageenan), were determined. The PS lead to substantial increase in the hydrolase level. The percentage of viral particles undergoing destructive change also increases in leaves treated with PS 24 h before infection. We suppose that the PS-mediated hydrolase activation promotes intracellular destruction of the viral particles and, thus, comprises one of the PS-induced protective mechanisms limiting intracellular viral accumulation. [ABSTRACT FROM AUTHOR]

The effect of chitosan on the accumulation and state of tobacco mosaic virus (TMV) in mesophyll cells of Nicotiana tabacum L. var. Samsun leaves is studied in the early stage of the development of the infection (3 days after infection of leaves). In the cells of leaves treated with chitosan 24 h before infection, the virus accumulated to a lesser degree than in the control. With the use of chitosan, TMV-specific granular inclusions were often observed in infected cells, the presence of which is ascribed to the early stages of virus reproduction, whereas the control cells contained mainly tubular inclusions formed from granular inclusions at the late stages of the infectious processes. This shows that chitosan delays the development of the infection. In the phosphotungstic acid-treated juice preparation made from infected leaves, abnormal (swollen and thin), as well as normal, TMV particles were observed. The appearance of abnormal viral particles seems to result from the virus-induced activation of intracellular lytic processes. In chitosan-treated infected cells, the lytic activity was the highest and the number of abnormal viral particles increased compared to the control. It is suggested that the chitosan-mediated stimulation of lytic processes that cause the destruction of TMV particles may be one of the protective mechanisms that limit the accumulation of the virus in cells. [ABSTRACT FROM AUTHOR]

Ultrastructural examination of tobacco mosaic virus-induced local lesions growing in Datura stramonium leaves is carried out. It is demonstrated that, in the central area of the lesions, the cell response to viral invasion is not uniform. Most cells exhibited an acute hypersensitive reaction (HR) and underwent rapid and complete necrosis. However, some cells, despite considerable virus accumulation and immediate contact with completely collapsed cells, maintained a certain degree of structural integrity. Analysis performed showed that the proportion of collapsed and uncollapsed cells in the lesion centre 3 to 5 days after infection essentially did not change. These data suggest that the absence of HR in some cells in the lesion centre is not due to an early stage of infection but is likely caused by cell tolerance of the virus. [ABSTRACT FROM AUTHOR]

Enzymatic (the action of lysozyme) and chemical (the action of hydrogen peroxide) hydrolysis of chitosans with various degree of acetylation (DA)-25, 17, and 1.5%-was performed. Purification and fractioning of the hydrolysis products were performed using dialysis, ultrafiltration, and gel-penetrating chromatography. Low-molecular (LM) derivatives of the polysaccharide with molecular masses from 17 to 2 kDa were obtained. The study of their antiviral activity against the tobacco mosaic virus (TMV) showed that these samples inhibited the formation of local necroses induced by the virus for 50-90%. The antiviral activity of the LM chitosans significantly increased with the lowering of their polymerization degree. Furthermore, the products of the enzymatic hydrolysis possessed lower activity than the chitosan samples obtained as a result of chemical hydrolysis. It was revealed that the exhibition of the antiviral activity weakly depended on the degree of acetylation of the samples. [ABSTRACT FROM AUTHOR]

The effect of κ/β-carrageenan from red alda Tichocarpus crinitus on the development of a potato virus X (PVX) infection in the leaves of Datura stramonium L. has been studied. The treatment of leaves with carrageenan stimulates a protein synthesis in the cells, causing an increase in the size of nucleoli and in the number of mitochondria and membranes of the rough endoplasmic reticulum. At the same time, such treatment slightly stimulates lytic processes, causing an increase in the number of smooth endoplasmic reticulum cisternae, dictyosomes, and cytoplasmic vacuoles and the formation of cytoplasmic electron-transparent zones. The carrageenan-induced stimulation of lytic processes results in the destruction of viral particles and can be considered as one of the defense mechanisms, preventing the intracellular accumulation of virus. The carrageenan-stimulated formation of PVX-specific laminar structures, able to bind viral particles and, therefore, prevent their intracellular translocation and reproduction, represents another carrageenan-induced mechanism of the antiviral defense in plant cells. [ABSTRACT FROM AUTHOR]

The effect of disodium salt of 2-acetyl-4-hydroxycarbonylmethylthio-5-chlorocyclopent-4-en-1,3-dione on development of the infection caused by tobacco mosaic virus in the leaves of two Nicotiana tabacum L. cultivars-an hypersensitive cultivar Xanthi-nc and systemically affected Samsun-was studied. The results suggest that this compound interferes with reproduction of the virus. This antiviral effect displayed the highest activity when applied in a mixture with the virus, presumably due to its action on both the plant and the virus. [ABSTRACT FROM AUTHOR]

Spermatogenesis in silver salmon Oncorhynchus kisutch and cherry salmon O. masou was studied by transmission electron microscopy. The spermatogenic cells of both species have been shown to have no considerable differences in their dimensional and ultrastructural parameters. The characteristic peculiarity of spermatogonia was the presence of a germ determinant substance, which is the cytoplasmic marker of sex line cells. The primary and secondary spermatocytes, as well as early spermatids, were arranged in gonads as cell clusters at the same stage of development. In spermiogenesis, the regular appearance of the electron-lucent vesicle was observed, which forms a structural complex with the apical condensation of the nuclear membrane. This complex is morphologically similar to the not-yet-formed spermatid acrosomes in many Metazoa and is referred to by the authors as an acrosome-like structure (AS). At the final stage of spermiogenesis, the disappearance of an AS allows one to considering it to be a temporarily existing structure that recapitulates the ancestral morphotype of salmonid sperm. Spermatozoa of the both species are typical, primitive, acrosome-lacking cells, which are characteristic of many representatives of Teleostei that have external insemination. [ABSTRACT FROM AUTHOR]

The accumulation of potato virus X (PVX) in mesophyll cells of detached Datura stramonium L. leaves treated with fucoidan from brown algae Fucus evanescens C. Ag. have been evaluated by electron microscopy during the early infection period (three days after infection). It was found that cells of the leaves treated with fucoidan 24 h before infection accumulated virus less than untreated control. Ultrastructure-morphometric assay showed that fucoidan treatment causes an increase in the protein-synthesizing capability of cells (nucleolus dimention and amount of both mitochondria and rough endoplasmic reticulum membranes increased). At the same time, fucoidan treatment slightly activates the lytic compartment, which leads to the destruction of virus particles. Therefore, it may be considered that fucoidan induces a cellular defense mechanism that limits virus accumulation. Stimulation by the fucoidan of the formation of PVX-specific laminar structures able to bind virus particles may be another antiviral cell defense mechanism induced by the virus that prevents PVX reproduction and its intra- and intercellular transport. [ABSTRACT FROM AUTHOR]

The influence of κ/β-carrageenan from red marine alga Tichocarpus crinitus on the development of tobacco mosaic virus (TMV) infection in Xanthi-nc tobacco leaves was studied. It was shown that the number of necrotic lesions on the leaves inoculated with the mixture of TMV (2 μg/ml) and carrageenan (1 mg/ml) was reduced by 87%, compared to the leaves inoculated with the virus only. The suppression of virus infection was also observed when leaves were treated with carrageenan 24 h before or 24 h after leaf inoculation with TMV; however, in these cases, suppression was less evident than after inoculation with the virus-polysaccharide mixture. It is supposed that the antiviral activity of carrageenan applied together with TMV may be explained by its action not only on the plant but also on the virus itself. The inhibitory effect of carrageenan pretreatment can be explained by its favorable effect on tissue resistance to infection. The suppression of this resistance by actinomycin D indicates that carrageenan functions via its action on the cell genome. [ABSTRACT FROM AUTHOR]

Abstract  The effects of selenium (0.01, 0.5, 1, 5 and 10 mg/liter) on the growth and ultrastructure of the microalga Dunaliella salina were investigated following its transfer into clean water. Selenium concentrations of 5 and 10 mg/liter were toxic to D. salina, and reinoculation of microalga into clean water did not prevent it from total mortality. When reinoculated from medium with 0.01 mg Se/liter, the cell population density of D. salina was restored in 14 days. The number of ultrastructural alterations in cells was the same as in the control, while the excretory activity of microalga between days 4 and 10 of this experiment was higher. Cell population growth of D. salina transferred from 0.5 and 1 mg Se/liter was lower than in the control. No ultrastructural defects were observed in microalga reinoculated from medium with a selenium concentration of 0.5 mg/liter and the excretion level corresponded to that at 0.01 mg/liter. Various types of ultrastructural damage were found in microalga from medium with 1 mg Se/liter, which was previously reported to be threshold for D. salina; however, the number of cell injuries decreased with increasing time in clean medium. Excretory activity was decreased at the beginning of experiment; but after 7 days, it was restored to the control level. Though there were no ultrastructural alterations in microalgal cells from medium with 0.5 mg Se/liter, we assume that they had molecular defects that could inhibit the cell population growth. The study of microalgae following their reinoculation from medium containing toxicants into clean medium can be a useful method for evaluating algal survival after toxic exposure. [ABSTRACT FROM AUTHOR]

Some peculiarities of the lipid composition of the outer membrane of the marine Gram-negative bacterium Chryseobacterium indoltheticum CIP 103168T have been studied. It is found that C. indoltheticum cells do not contain phosphatidylglycerol. Lipopolysaccharide could not be extracted by conventional methods; therefore, lipid A was isolated by hydrolysis of whole bacterial cells with 10% acetic acid with subsequent treatment with a chloroform: methanol mixture. The isolated lipid A has an unusual monosaccharide structure and constitutes 1-phosphate- D-glucosamine acylated with ( R)-3-hydroxy-15-methylhexadecanoic and ( R)-3-hydroxy-13-methyltetradecanoic acids at C2 and C3 atoms, respectively. The C. indoltheticum cells are shown to have a capsule; its polysaccharide apparently fulfils the LPS function. [ABSTRACT FROM AUTHOR]

Abstract  This study examines the effects of selenium in concentrations of 0.01, 0.5, 1, 5, and 10 mg/liter on the growth and ultrastructure of the microalga Dunaliella salina. Selenium in concentrations of 0.01 and 0.5 mg/liter stimulated cell population growth, while the number of ultrastructural alterations was the same as in the control cells. At a selenium concentrations of 1 mg/liter, cell population growth slightly decreased by the end of the experiment, and there was some increase in the number of cells with damaged organoids and in the number of completely destroyed cells. As well, the excretory function of cell vacuoles was suppressed, and the autophagic activity of these vacuoles was activated to destroy the cytoplasm and nucleus. Concentrations of 5 and 10 mg/liter were toxic to D. salina, suppressing cell population growth and promoting extensive destructive changes. The threshold concentration of selenium for D. salina was 1 mg/liter, which is 1000 times greater than the maximum permissible concentration (MPC). The fact that the microalga was able to survive for several days in this concentration is indicative of its high resistance to selenium. [ABSTRACT FROM AUTHOR]

The effect of fucoidan (1.3; 1.4-α-L-fucan), a sulfated polysaccharide from the brown alga Fucus evanescens on the formation of specific granular and tubular inclusions induced by tobacco mosaic virus (TMV) and consisted presumably of the virus-coded protein components of the viral replicase was investigated in the TMV-infected leaves of tobacco ( Nicotiana tabacum L.). In four days after inoculation of the leaves with a TMV preparation (1 mg/ml), the signature of infection in a presence of fucoidan (1 mg/ml) was a preferential formation of intracellular granular inclusions, which were related to early stages of the virus reproduction. When infected leaves were not treated with fucoidan, their cells contained mainly tubular inclusions, which were presumably formed from the granular ones on the last stages of the infection process. These observations demonstrated that fucoidan delayed the development of the TMV-induced infection. [ABSTRACT FROM AUTHOR]

The fragmentation of the biologically active 1,3;1,6-β-D-glucan Antivir by endo-1,3-β-D-glucanase LIV from crystalline styles of the marine mollusk Spisula sachalinensis was carried out. It was found that low molecular mass oligomers possessing a stabilizing effect on membranes and anti-viral activity against tobacco mosaic virus appeared in the process of enzymatic hydrolysis of Antivir. Biological activity of 1,3;1,6-β-D-glucooligo-and polysaccharides was found to be associated with molecular mass (polymerization degree ( n) not less than 14) and with presence of intralinked β-1,6-connected monosaccharide residues. Probably, decrease in molecular mass is compensated by increase in number of intralinked β-1,6-connected monosaccharide residues. [ABSTRACT FROM AUTHOR]

The influence of culture conditions and plasmids on immunoglobulin (Ig)-binding activity of two isogenic strains of Yersinia pseudotuberculosis (plasmid-free strain 48−82− and strain 48+82+ bearing plasmids pYV48 and pVM82) was studied. The highest activity was observed in the bacteria grown on glucose-containing liquid medium in the stationary growth phase. The Ig-binding activity of the bacteria cultured on the liquid medium at pH 6.0 was about 1.5-fold higher than that of the bacteria grown at pH 7.2. Expression of the Ig-binding proteins (IBPs) was most influenced by temperature of cultivation. The IBP biosynthesis was activated in the bacteria grown at 4°C and markedly decreased in those grown at 37°C. The Ig-binding activity of lysates from the bacteria was caused by proteins with molecular weights of 7–20 kD. The activities of the plasmid-free and plasmid-bearing Y. pseudotuberculosis strains (48−82− and 48+82+, respectively) were analyzed, and the plasmids were shown to have no effect on the IBP expression and biosynthesis, which seemed to be determined by chromosomal genes. [ABSTRACT FROM AUTHOR]

Accumulation of considerable amounts of viral particles has been demonstrated in parenchymal cells of young leaves in tobacco cultivar Samsun systemically infected with any of studied tobacco mosaic virus (TMV) strains isolated from pepper (TMV-p), tomato (TMV-t), and eggplant (TMV-e). Abnormal (swollen and thin) virions were found, which points to their destruction. Cell infection with all studied strains was accompanied by the activation of the lysosomal compartment manifested as formation of nascent dictyosomes, elements of smooth endoplasmic reticulum, cytoplasmic vacuoles, various vesicles, invaginated mitochondria, and multivesicular bodies. The studied viral strains could be arranged in the following sequence according to the degree of lysosomal compartment stimulation and induction of intracellular lytic processes mediating the destruction of viral particles and cell structures: TMV-p > TMV-e > TMV-t. [ABSTRACT FROM AUTHOR]

The effect of fucoidan from the brown alga Fucus evanescens on the spread of infection induced by tobacco mosaic virus (TMV) was investigated in the leaves of tobacco ( Nicotiana tabacum L.) of two cultivars (Ksanti-nk and Samsun). In the leaves of cv. Ksanti-nk inoculated with a mixture of TMV preparation (2 μg/ml) and fucoidan (1 mg/ml), the number of local necrotic lesions induced by the virus decreased by more than 90% as compared with the leaves inoculated with the virus alone. In tobacco leaves of cv. Samsun, virulence and the concentration of the virus 3 days after inoculation with the same mixture of TMV and fucoidan were by 62 and 66%, respectively, lower than in the leaves inoculated with TMV alone. As the infection spread, the inhibitory effect of fucoidan decreased. When the leaves were treated with fucoidan before and after the inoculation with TMV, its antiviral activity was less pronounced than when a mixture of the virus and the polysaccharide was used as inoculum. Electron microscopic investigation of TMV mixed with fucoidan often showed agglutinated virions. The highest virulence of the mixture (TMV preparation, 12 μg/ml, plus fucoidan, 1 mg/ml) was observed upon its twofold dilution, and after that it decreased. It was concluded that, when the leaves were inoculated with the mixture of TMV and fucoidan, the latter affected not only the plant but the virus as well. Treatment of tobacco leaves, cv. Ksanti-nk, with actinomycin D (10 μg/ml) 24 h before the inoculation with TMV almost completely suppressed the effect of fucoidan, indicating that fucoidan acted at a gene level. [ABSTRACT FROM AUTHOR]

Difficulties in characterization of spermatozoa of the Metazoa are now related to insufficiency of the traditional terms “primitive spermatozoon,” “modified spermatozoon,” and “aberrant spermatozoon” introduced by G. Retzius and A. Franzen for description of intermediate forms discovered in the 20th century. In this respect, some authors propose to reject the Retzius' and Franzen's terms and turn to the terminological system of G. Rouse and B. Jamieson, the terms of which (“ectaquaspermatosoa,” “entaquaspermatozoa,” and “introspermatozoa”) determine specific features of insemination, but do not reflect the structure of spermatozoa. The assertion of “helplessness” of the traditional structural Retzius' and Franzen's terms is unfounded. Their preservation is desirable if one wishes to preserve the comparative-morphological approach to the characterization of male gametes of the Metazoa. The terms “primitive spermatozoon,” “modified spermatozoon,” and “aberrant spermatozoon” will become more universal if the method of their combined utilization is applied. [ABSTRACT FROM AUTHOR]

The ultrastructural mechanism of postspawning sperm resorption in the testes of the sea urchin Strongylocentrotus nudus is described. Two types of phagosomes (containing sperm and containing residual bodies) are formed in the cytoplasm of nutritive phagocytes. The phagosomes fuse with electron-dense globules, and their contents are gradually destroyed. Afterward, phagosomes are transformed into electron-transparent vacuoles, which are finally compressed by the surrounding cytoplasm. [ABSTRACT FROM AUTHOR]

Abstract The process of resorption of spermatozoa is described in the testes of the starfish Asterina pectinifera. It is shown that the mode of resorption of the male gametes in this species is different from that in the starfish Asterias vulgaris (see Walker [17, 18]), A. amurensis, and Aphelasterias japonica (see Kas’yanov et al. [ABSTRACT FROM AUTHOR]

Abstract The process of the destruction of nonreleased spermatozoa was studied using TEM in the postspawning gonads of the chum salmon Oncorhynchus keta and the pointhead flounder Cleisthenes herzensteini, as representatives of monocyclic and polycyclic fishes respectively. It was shown that in both species residual sperm cells are destroyed through fragmentation of chromatin and the entire cell. It is supposed that the process of destruction in this case is connected with autolytic disintegration known in some multicellular animals, but never described for Teleostei. [ABSTRACT FROM AUTHOR]

The ultrastructural mechanisms of waste-sperm phagocytosis and postspawning shrinkage were studied for accessory cells (nutritive phagocytes; NPs) of the sea urchinAnthocidaris crassispina. Sperm cells were phagocytosed by NPs; they penetrated into the cytoplasm of the NPs inside heterophagosomes formed by an invagination of the cell membrane. Single-sperm-containing heterophagosomes aggregated to form large multisperm heterophagosomes that were accompanied by cytoplasmic vesicles and lipids. Two types of vesicle, viz., Golgi-complex-derived electron-dense vesicles (“zymogen granules”) and smooth-endoplasmic-reticulum-derived electron-lucent vesicles, were incorporated within multisperm heterophagosomes. Completed multisperm heterophagosomes were transformed into electron-dense remnant bodies, the content of which underwent destruction, resulting in “empty” vacuoles inside the remnant body. The “empty” vacuoles were then compressed by the surrounding cytoplasm. Shrinkage of NPs occurred upon completion of sperm degeneration in gonad tubules. This process was undertaken by structures termed cell-size-reducing autolysosomes, which performed two types of autolysis, and resulted in the formation of “cheese-hole”-like vacuoles in the cytoplasm of NPs. Subsequent cytoplasmic compression of these vacuoles was required for the reduction in size of NPs, an essential event for remodeling the cell for the next gametogenetic cycle. [ABSTRACT FROM AUTHOR]

A phenomenon of dimorphism in spermatozoa has been revealed for the sea urchin Strongylocentrotus nudus. The spermatozoa are different in the configuration of the circular mitochondrion. The bulk of male gametes (73.4%) have a symmetrical mitochondrion, whereas the remainder spermatozoa (26.6%) have an asymmetrical one. No other ultrastructural differences in the structure of spermatozoa have been revealed. The two types of spermatozoa are supposed to represent different kinds of normal gametes capable of fertilization. [ABSTRACT FROM AUTHOR]

Certain physicochemical properties of glycoglycerolipids from marine alga Laminaria japonica (monogalactosyldiacylglycerol, digalactosyldiacylglycerol, and sulfoquinovosyldiacylglycerol) and their ability to be incorporated into immunostimulating complexes (ISCOMs) used for delivery of microbial and tumor antigens in vesicular form were comparatively described. These glycolipids proved to considerably differ by fatty acid composition, degree of unsaturation, and phase transition temperatures. Production of modified ISCOMs through incorporation of these glycolipids into the vesicle instead of the glycolipid component was demonstrated. Preliminary data demonstrated no significant increase in immune response to Yersinia pseudotuberculosis porin in the modified (with monogalactosyldiacylglycerol) and classical (with phosphatidylcholine) ISCOMs as compared to pure porin. [ABSTRACT FROM AUTHOR]