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Background Blooms of marine microalgae play a pivotal role in global carbon cycling. Such blooms entail successive blooms of specialized clades of planktonic bacteria that collectively remineralize gigatons of algal biomass on a global scale. This biomass is largely composed of distinct polysaccharides, and the microbial decomposition of these polysaccharides is therefore a process of prime importance. Results In 2020, we sampled a complete biphasic spring bloom in the German Bight over a 90-day period. Bacterioplankton metagenomes from 30 time points allowed reconstruction of 251 metagenome-assembled genomes (MAGs). Corresponding metatranscriptomes highlighted 50 particularly active MAGs of the most abundant clades, including many polysaccharide degraders. Saccharide measurements together with bacterial polysaccharide utilization loci (PUL) expression data identified β-glucans (diatom laminarin) and α-glucans as the most prominent and actively metabolized dissolved polysaccharide substrates. Both substrates were consumed throughout the bloom, with α-glucan PUL expression peaking at the beginning of the second bloom phase shortly after a peak in flagellate and the nadir in bacterial total cell counts. Conclusions We show that the amounts and composition of dissolved polysaccharides, in particular abundant storage polysaccharides, have a pronounced influence on the composition of abundant bacterioplankton members during phytoplankton blooms, some of which compete for similar polysaccharide niches. We hypothesize that besides the release of algal glycans, also recycling of bacterial glycans as a result of increased bacterial cell mortality can have a significant influence on bacterioplankton composition during phytoplankton blooms.

Single-crystal electron paramagnetic resonance spectra of electron-irradiated stishovite, measured at temperatures from 3.5 to 294 K, reveal three S = 1/2 radiation-induced defects: an aluminum-associated oxygen hole center and two nd 1 centers (Ti3+ and W5+). The aluminum-associated oxygen hole center, characterized by an orthorhombic site symmetry, coaxial matrices of the electronic Zeeman g, nuclear hyperfine A(27Al) and nuclear quadrupole P(27Al), and the orientation of the g-minimum axis along an O–O direction and those of the unique A(27Al) and P(27Al) axes perpendicular to the O–O direction, is an Al–O2 3− center, with the unpaired electron equally distributed on two equatorial oxygen atoms of a substitutional Al3+ ion at the octahedral Si site. Fully optimized Al-doped structure, theoretical 27Al nuclear hyperfine and quadrupole coupling constants and directions, and 3D spin densities from periodic hybrid density functional theory calculations provide further support for this structural model. Spin Hamiltonian parameters of the Ti3+ and W5+ centers, which are confirmed by their diagnostic 47Ti, 49Ti and 183W hyperfine structures, arise from electron trapping on substitutional Ti4+ and W6+ ions at the octahedral Si site.

Single-crystal electron paramagnetic resonance (EPR) spectra of fast-electron-irradiated quartz, after annealing at 120 and 200°C, reveal five new E′ type centers, herein labeled $$ E_{ 5}^{\prime } ,\,E_{ 6}^{\prime } ,\,E_{ 7}^{\prime } ,\,E_{ 8}^{\prime } ,\,{\text{and}}\,E_{ 9}^{\prime } $$ . Centers $$ E_{ 5}^{\prime } ,\,E_{ 7}^{\prime } ,\,{\text{and}}\,E_{ 9}^{\prime } $$ are characterized by the orientations of the unique principal g and A(29Si) axes close to a short Si–O bond direction, hence representing new variants of the well-established $$ E_{ 1}^{\prime } $$ center. Centers $$ E_{ 6}^{\prime } $$ and $$ E_{ 8}^{\prime } $$ have the orientations of the unique principal g and A(29Si) axes approximately along a long Si–O bond direction, similar to the $$ E_{ 2}^{\prime } $$ centers. Therefore, these new E′ type centers apparently arise from the removal of different oxygen atoms and represent variable local distortions around the oxygen vacancies.

Several new radiation defects with total electron spin S = 1 occurring in electron-irradiated, synthetic α-quartz have been observed by using electron paramagnetic resonance spectroscopy. These defects are considered to be biradicals, i.e., pairs of S = 1/2 species. The concentration of these centers depends on the condition of the fast-electron irradiation. They have different decay behaviors that allow measurements of any individual species especially when it predominates over the others. The primary spin Hamiltonian parameter matrices g 1, g 2, D have now been determined for two similar defects, which herein are labeled $$ E_{2}^{\prime \prime } $$ and $$ E_{4}^{\prime \prime } $$ . Inter-electron distances estimated by using the magnetic dipole model, suggest that the structures of centers $$ E_{2}^{\prime \prime } $$ and $$ E_{4}^{\prime \prime } $$ both involve the unpaired electrons each located in orbitals of two silicon atoms next to a common oxygen vacancy but which have slightly different Si–Si distances at 0.90 and 0.79 nm, respectively. This model is consistent with previous DFT calculations of the triplet configurations with local energetic minima. Observed decay behaviors suggest a transformation of centers $$ E_{2,4}^{\prime \prime } $$ to the analogous $$ E_{1}^{\prime \prime } $$ center. These triplet centers in quartz provide new insights into the structures of analogous defects in amorphous silica.

The X- and W-band single-crystal electron paramagnetic resonance spectra of an electron-irradiated natural quartz permit quantitative analysis of a 29Si hyperfine structure (A ~12.6 MHz) and an 27Al hyperfine structure (A ≤ 0.8 MHz) for a previously reported hole-like center. The 29Si hyperfine structure arises from interaction with two equivalent Si atoms and is characterized by the direction of the unique A axis close to a Si–O bond direction. The 27Al hyperfine structure, confirmed by pulsed electron nuclear double resonance and electron spin echo envelope modulation spectra, is characterized by the unique A axis approximately along a twofold symmetry axis. These 29Si and 27Al hyperfine data, together with published theoretical results on peroxy radicals in SiO2 as well as our own density functional theory (DFT) calculations on model peroxy centers, suggest this hole-like center to have the unpaired spin on a pair of oxygen atoms linked to two symmetrically equivalent Si atoms and a substitutional Al3+ ion across the c-axis channel, a first peroxy radical in quartz. The nuclear quadrupole matrix P also suggests that the Al3+ ion corresponds closely to the diamagnetic precursor to the [AlO4]0 center.

Single-crystal electron paramagnetic resonance (EPR) spectra of a natural citrine quartz without any artificial irradiation, measured at W-band frequencies (∼94 GHz) and temperatures of 77, 110 and 298 K, allow better characterization of three previously-reported Centers (#6, #7 and B) and discovery of three new defects (B′, C′ and G′). The W-band EPR spectra reveal that Centers #6 and #7 do not reside on twofold symmetry axes, contrary to results from a previous X-band EPR study. The W-band spectra also show that the previously reported Center B is a mixture of two defects (B and B′) with similar g matrices but different-sized 27Al hyperfine structures. Center C′ has similar principal g values to the previously reported Center C but is distinct from the latter by a larger 27Al hyperfine structure with splittings from 0.10 to 0.22 mT. Also, Center G′ has a similar g matrix to the previously reported Center G but a different 27Al hyperfine structure with splittings from 0.41 to 0.53 mT. These spin-Hamiltonian parameters, together with observed thermal properties and microwave-power dependence, suggest that Centers #6 and #7 probably represent O 2 3− type defects. Centers B and B′ are probably superoxide radicals (O 2 − ) with the unpaired spin localized on the same pair of oxygen atoms around a missing Si atom but linked to a substitutional Al3+ ion each at different neighboring tetrahedral sites. Similarly, Centers G and G′ are most likely superoxide radicals with the unpaired spin localized on another pair of oxygen atoms around a missing Si atom and linked to a substitutional Al3+ ion each at different neighboring tetrahedral sites. Center C′ is probably an ozonide radical associated with a missing Si atom and linked to a substitutional Al3+ ion at the neighboring tetrahedral site. This study exemplifies the value of high-frequency EPR for discrimination of similar defect centers and determination of small local structural distortions that are often difficult to resolve in conventional X- and Q-band EPR studies.

Single-crystal W-band electron paramagnetic resonance (EPR) spectra of an electron-irradiated quartz, measured at room temperature, 110 and 77 K, disclose three previously reported hole centers (#1, G and an ozonide radical). The W-band EPR spectra of these three centers clearly resolve six magnetically nonequivalent sites each, whereas previous X- and Q-band EPR studies reported Centers #1 and the ozonide radical to consist of only three symmetry-related components and interpreted them to reside on twofold symmetry axes in the quartz structure. The calculated g matrices of Center #1 and the ozonide radical show that deviations from twofold symmetry axes are

Structural alterations in mitochondrial DNAs (mtDNAs) from a plant of a sterile sugar beet line, callus derived from it, suspension-cultured cells and plants regenerated from the callus were studied. BamHI restriction analysis revealed that structural alterations between the mtDNAs of the callus and the control plant had occurred. Multiple rearrangements were also demonstrated in the mtDNA from the suspension culture, of which some were similar to those appearing in the callus, and others had arisen de novo. Rearrangements were also identified by means of blot hybridization of BamHI-digested mtDNA from suspension-cultured cells with the genes encoding subunit II of cytochrome oxidase (cox II) and subunit 1 of NADH-dehydrogenase (Nd1). No alterations were observed in the mitochondrial genome of the callus and regenerants. The location of the genes for the α-subunit of F1-ATPase (atpA) and apocytochrome b (cob) in the mtDNA remained unchanged. Our salient finding was of a plant with an altered mitochondrial genome as judged by EcoRI and BamHI restriction analysis. This exceptional plant had retained the sterile phenotype like all of the other regenerants and the parent. The set of plasmid-like molecules of mtDNA remained the same as that in the control plant and in all of the regenerants, callus and suspension-cultured cells. The only type of plasmid-like molecule found in all of the DNAs was the 1.6-kbp minicircle, which is a feature of sterile cytoplasms. These structural changes in mtDNA were obviously a consequence of somaclonal variation during the in vitro cultivation of the sugar beet cells.

Derivatives of plasmid pBR327 with the tet gene interrupted by 165 pb or 401 bp direct repeats were constructed. In cells harboring these plasmids, deletions which restored the wild-type tet gene gave rise to tetracycline-resistant colonies, thereby allowing a simple phenotypic test for deletion formation. The frequencies of deletions in these plasmids were measured in Escherichia coli strains proficient or deficient in general recombination. The structure of plasmid DNA isolated from tetracycline-resistant transformants was analyzed by agarose gel electrophoresis, restriction mapping and sequencing. The data presented here demonstrate that deletion formation is always associated with dimerization of plasmid DNA. Dimeric plasmids were of two types. Those which carried both a deletion and a compensating duplication were the major type in a Rec+ background and were rare in recA, recF, recJ and recO backgrounds. Dimers of the second type contained deletions, but no compensating duplications, and their formation was RecA-independent. The data presented demonstrate that deletion formation mediated by long direct repeats is mainly the result of unequal crossing-over between two plasmid molecules.

Mitochondrial (mt) DNA from eight cytoplasmic male-sterile (cms) lines of sugar beet from different breeding stations was investigated by restriction fragment analysis and Southern hybridization. All cms lines showed similar but not identical restriction and hybridization signal patterns, readily distinguishable from those of fertile (N) cytoplasm. Digestion of the mtDNA with BamHI, EcoRI, SalI, and XhoI revealed distinct differences between the sterile lines, and six subtypes of the S cytoplasm could be distinguished. Differences between the sterile lines were confirmed by hybridization with a \(\overline{\overline {COX}} II\) gene probe revealing minor, line-specific hybridization signals. The data presented provide evidence for the existence of considerable variation within the only commercially used source of cms in the sugar beet, the Owen's type of cytoplasm.

Among the fertile sugar beet lines with nuclear sterility maintenance genes, rf, in a homozygous recessive state, sublines capable of reverting spontaneously at a high rate to sterility were identified. Of 24 related fertile sublines studied, 6 were found to spontaneously revert to sterility with a frequency of about 19%. Genetic analysis confirmed the cytoplasmic nature of spontaneously arising sterility. Reversion to sterility in these sublines was accompanied by alterations in the mitochondrial genome structure: loss of the autonomously replicating minicircle c (1.3 kb) and changes in the restriction patterns of high-molecular-weight mitochondrial DNA (mtDNA). Southern hybridixation analysis with cloned minicircle c as a probe revealed no integration of this DNA molecule into the main mitochondrial and nuclear genomes of the revertants. Comparative BamHI and EcoRI restriction analysis of the mtDNA from the sterile revertants and fertile parental subline showed that the spontaneous reversion is accompanied by extensive genomic rearrangement. Southern blot analysis with cloned α-subunit of F1-ATPase (atpA) and cytochrome c oxidase subunit II (COX II) genes as probes indicated that the changes in mtDNA accompanying spontaneous reversion to sterility involved these regions. The mitochondrial genomes of the spontaneous revertants and the sterile analogue were shown to be identical.

Estradiol is demonstrated to induce histidine decarboxylase, and histamine is shown to activate adenylate cyclase in rat uterus. Histamine and cyclic 3',5'-AMP mimic the effects of estradiol in that they enhance RNA synthesis, induce glycolytic enzymes and uterus imbibition. The data suggest that estradiol enhances by induction of histidine decarboxylase the formation of histamine, the latter activates adenylate cyclase providing accumulation of cyclic 3',5'-AMP, which, probably, induces glycolytic enzymes through phosphorylation of chromatin proteins, and mediates other estradiol effects. The chain of successively acting enzymes and mediators constitutes, obviously, a cascade amplifying estradiol action. Since histamine is known to act as an intercellular mediator, attempts were made to find out the distribution of estradiol histamine and cyclic 3',5'-AMP among uterus cells. Autoradiography has shown that [3H]-estradiol is bound by the nuclei of myometrium cells, [3H]-histamine was found above the cytoplasm of these cells, E13H]-cyclic 3',5'-AMP is selectively bound by the cells of capillary endothelium of the uterus. The estradiol mediators seem to spread effect of hormone on cells of different types which form together a kind of multicellular functional system.

Impurity inhomogeneities and other structural de- fects have been studied by means of transmission electron microscopy (TEM), X-ray microanalysis and electron para- magnetic resonance (EPR) in untreated and heat-treated quartz samples of three genetic types: hydrothermal, peg- matitic and magmatic. The impurities present are A1, Na and H20 , which occupy tetrahedral (A13+) or interstitial (Na +, H20 ) positions in the quartz lattice. Impurities form imperfections of various degrees of seg- regation: from point defects to micropores with a gas-liquid content. Their size, form, density and distribution in the lattice depend on the formation conditions of the quartz, the presence of dislocations and plane defects serving as sinks for the impurity atoms, and the heat treatment regime. Experimental data indicate that gas-liquid inclusions of di- mensions up to some microns are the result of impurity segregation during postcrystallizational cooling. Crystalline quartz amorphizes upon electron irradiation. A model of structural water explaining experimentally ob- served features of this phenomenon is proposed whereby the water molecule, represented as a dipole, enters microre- gions of the silica lattice with a high impurity content and there forms a bond between 'defective' (SiO3) 2- and (A104) 5- tetrahedra. On irradiation, the Si---O donor-ac- ceptor bonds trap nonelastically scattered electrons and are ruptured as a result. The water released by this lattice dis- continuity forms microbubbles that diffuse along sinks into the larger micropores thus further increasing their volume.

Early postnatal treatment of rats or mice with different enzyme inducers (cortisol, galactose, steroid which induces mixed function oxidases) results in long-lasting changes in the activity of corresponding inducible enzymes.

Введение крысам пентнпептида гастрина, гистамина и 3′,5′-АМФ усиливают активность карбоангидразы в ⇒лизистой желудка крыс. Установлено, что актиномицин Ди циклогексимид тормозят только активацию карбоангидразы, визиваемую пентапептидом гастрина, и не влияют на зтот процесс, если он был стимулировах гистамином или 3′,5′-АМФ.