Bypolls will be held on Wednesday in 31 assembly seats spread across 10 states and Kerala's Wayanad Lok Sabha constituency, from where Congress general secretary Priyanka Gandhi Vadra is making her electoral debut. Though these bye-elections are not going to have any bearing on the governments, they are seen as a big test for the Congress and the INDIA bloc which failed to put up a united show in the recent Haryana assembly polls. Most of these seats fell vacant after the sitting MLAs contested the Lok Sabha elections and won while in some constituencies, the bypolls are being held due to death of the representatives. The Wayanad seat was vacated by Rahul Gandhi, who also won from the Rae Bareli parliamentary constituency which he kept. Voting will be held in seven seats in Rajasthan, six in West Bengal, five in Assam, four seats in Bihar, three in Karnataka, two seats in Madhya Pradesh, and one seat each in Chhattisgarh, Gujarat, Kerala and Meghalaya. Votes will be counted on November 23.

At least three Indian-Americans have won from their respective states in the Assembly elections that were held along with the general elections this week.

Chen Shih-chung told international media at a news conference that global health officials "have not been honest and failed in their responsibilities," in an apparent reference to the UN World Health Organization that oversees the assembly.

"At present, the House is not in session. The Monsoon Session of the UP Legislative Assembly should be held some time in August and I am optimistic that by then the situation would have changed," the speaker told PTI in an interview.

Only 200 of the 403 MLAs will be able to sit inside the Uttar Pradesh Assembly if social distancing norms are implemented in the House as there are not enough seats, Speaker Hriday Narayan Dixit said. However, Dixit is "optimistic" and feels that by the time the next sitting of the Legislative Assembly is convened the situation will improve. "At present, the House is not in session. The Monsoon Session of the UP Legislative Assembly should be held some time in August and I am optimistic that by then the situation would have changed," the speaker told PTI in an interview. When asked to elaborate, Dixit said, "If we adhere to social distancing and leave one seat vacant, we will not have enough seats. There are 403 MLAs. Already there are not enough seats for everyone." "There is a shortage of 10-12 seats. The work goes on as (generally) 10-12 (members) are absent. In these circumstances, if one seat is left vacant then not more than 200 MLAs will be able to sit," he said. On being asked

Lucknow, May 10: Only 200 of the 403 MLAs will be able to sit inside the Uttar Pradesh Assembly if social distancing norms are implemented in the House as there are not enough seats, Speaker Hriday Narayan Dixit said. However, Dixit

It has been revealed that in cylindrical nano-confinement, the hydrogen-bonding direction of nylon-12 crystals in the rod could self-assemble to be parallel to the long axis of the rod. The dominant growth direction and hydrogen-bonding direction of the γ-form crystal in the long axis of the rod has been revealed by TEM–SAED and WAXD.

Mammalian Munc18 proteins are essential for membrane fusion and human health. Here, we review the literature describing structural and in vitro data, and identify a possible explanation for the conflicting functional roles that have been reported.

Solution structure of β-amylase 2 from Arabidopsis thaliana shows the role of the conserved N-terminus in enzyme tetramer formation.

Six new 1-aroyl-4-(4-meth­oxy­phen­yl)piperazines have been prepared, using coupling reactions between benzoic acids and N-(4-meth­oxy­phen­yl)piperazine. There are no significant hydrogen bonds in the structure of 1-benzoyl-4-(4-meth­oxy­phen­yl)piperazine, C18H20N2O2, (I). The mol­ecules of 1-(2-fluoro­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H19FN2O2, (II), are linked by two C—H⋯O hydrogen bonds to form chains of rings, which are linked into sheets by an aromatic π–π stacking inter­action. 1-(2-Chloro­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H19ClN2O2, (III), 1-(2-bromo­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H19BrN2O2, (IV), and 1-(2-iodo­benzo­yl)-4-(4-meth­oxyphen­yl)piperazine, C18H19IN2O2, (V), are isomorphous, but in (III) the aroyl ring is disordered over two sets of atomic sites having occupancies of 0.942 (2) and 0.058 (2). In each of (III)–(V), a combination of two C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. A single O—H⋯O hydrogen bond links the mol­ecules of 1-(2-hy­droxy­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H20N2O3, (VI), into simple chains. Comparisons are made with the structures of some related compounds.

Twelve 4-(4-meth­oxy­phen­yl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. The monohydrated benzoate, 4-fluoro­benzoate, 4-chloro­benzoate and 4-bromo­benzoate salts, C11H17N2O+·C7H5O2−·H2O (I), C11H17N2O+·C7H4FO2−·H2O (II), C11H17N2O+·C7H4ClO2−·H2O (III), and C11H17N2O+·C7H4BrO2−·H2O (IV), respectively, are isomorphous and all exhibit disorder in the 4-meth­oxy­phenyl unit: the components are linked by N—H⋯O and O—H⋯O hydrogen bond to form chains of rings. The unsolvated 2-hy­droxy­benzoate, pyridine-3-carboxyl­ate and 2-hy­droxy-3,5-di­nitro­benzoate salts, C11H17N2O+·C7H5O3− (V), C11H17N2O+·C6H4NO2− (VI) and C11H17N2O+·C7H3N2O7− (VII), respectively, are all fully ordered: the components of (V) are linked by multiple N—H⋯O hydrogen bonds to form a chain of rings; those of (VI) are linked into a three-dimensional framework by a combination of N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds and those of (VII), where the anion has a structure reminiscent of the picrate anion, are linked into a three-dimensional array by N—H⋯O and C—H⋯O hydrogen bonds. The hydrogensuccinate and hydrogenfumarate salts, C11H17N2O+·C4H5O4− (VIII) and C11H17N2O+·C4H3O3− (IX), respectively, are isomorphous, and both exhibit disorder in the anionic component: N—H⋯O and O—H⋯O hydrogen bonds link the ions into sheets, which are further linked by C—H⋯π(arene) inter­actions. The anion of the hydrogenmaleate salt, C11H17N2O+·C4H3O3− (X), contains a very short and nearly symmetrical O⋯H⋯O hydrogen bond, and N—H⋯O hydrogen bonds link the anions into chains of rings. The ions in the tri­chloro­acetate salt, C11H17N2O+·C2Cl3O2− (XI), are linked into simple chains by N—H⋯O hydrogen bonds. In the hydrated chloranilate salt, 2C11H17N2O+·C6Cl2O42−·2H2O (XII), which crystallizes as a non-merohedral twin, the anion lies across a centre of inversion in space group P21/n, and a combination of N—H⋯O and O—H⋯O hydrogen bonds generates complex sheets. Comparisons are made with the structures of some related compounds.

Two new chalcones containing both pyrazole and thio­phene substituents have been prepared and structurally characterized. 3-(3-Methyl-5-phen­oxy-1-phenyl-1H-pyrazol-4-yl)-1-(thio­phen-2-yl)prop-2-en-1-one, C23H18N2O2S (I), and 3-[3-methyl-5-(2-methyl­phen­oxy)-1-phenyl-1H-pyrazol-4-yl]-1-(thio­phen-2-yl)prop-2-en-1-one, C24H20N2O2S (II), are isomorphous as well as isostructural, and in each the thio­phene substituent is disordered over two sets of atomic sites having occupancies 0.844 (3) and 0.156 (3) in (I), and 0.883 (2) and 0.117 (2) in (II). In each structure, the mol­ecules are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds. Comparisons are made with some related compounds.

The stressosome transduces environmental stress signals to SigB to upregulate SigB-dependent transcription, which is required for bacterial viability. The stressosome core is composed of RsbS and at least one of the RsbR paralogs. A previous cryo-electron microscopy (cryo-EM) structure of the RsbRA–RsbS complex determined under a D2 symmetry restraint showed that the stressosome core forms a pseudo-icosahedron consisting of 60 STAS domains of RsbRA and RsbS. However, it is still unclear how RsbS and one of the RsbR paralogs assemble into the stressosome. Here, an assembly model of the stressosome is presented based on the crystal structure of the RsbS icosahedron and cryo-EM structures of the RsbRA–RsbS complex determined under diverse symmetry restraints (nonsymmetric C1, dihedral D2 and icosahedral I envelopes). 60 monomers of the crystal structure of RsbS fitted well into the I-restrained cryo-EM structure determined at 4.1 Å resolution, even though the STAS domains in the I envelope were averaged. This indicates that RsbS and RsbRA share a highly conserved STAS fold. 22 protrusions observed in the C1 envelope, corresponding to dimers of the RsbRA N-domain, allowed the STAS domains of RsbRA and RsbS to be distinguished in the stressosome core. Based on these, the model of the stressosome core was reconstructed. The mutation of RsbRA residues at the binding interface in the model (R189A/Q191A) significantly reduced the interaction between RsbRA and RsbS. These results suggest that nonconserved residues in the conserved STAS folds between RsbS and RsbR paralogs determine stressosome assembly.

The disposition of functional groups can induce variations in the nature and type of interactions and hence affect the molecular recognition and self-assembly mechanism in cocrystals. To better understand the formation of cocrystals on a molecular level, the effects of disposition of functional groups on the formation of cocrystals were systematically and comprehensively investigated using cresol isomers (o-, m-, p-cresol) as model compounds. Consistency and variability in these cocrystals containing positional isomers were found and analyzed. The structures, molecular recognition and self-assembly mechanism of supramolecular synthons in solution and in their corresponding cocrystals were verified by a combined experimental and theoretical calculation approach. It was found that the heterosynthons (heterotrimer or heterodimer) combined with O—H⋯N hydrogen bonding played a significant role. Hirshfeld surface analysis and computed interaction energy values were used to determine the hierarchical ordering of the weak interactions. The quantitative analyses of charge transfers and molecular electrostatic potential were also applied to reveal and verify the reasons for consistency and variability. Finally, the molecular recognition, self-assembly and evolution process of the supramolecular synthons in solution were investigated. The results confirm that the supramolecular synthon structures formed initially in solution would be carried over to the final cocrystals, and the supramolecular synthon structures are the precursors of cocrystals and the information memory of the cocrystallization process, which is evidence for classical nucleation theory.

As one of the most important phenomena in crystallization, the crystal nucleation process has always been the focus of research. In this work, influences of pre-assembly species and the desolvation process on the crystal nucleation process were studied. p-Nitro­benzoic acid (PNBA) was taken as a model compound to investigate the relationship between solution chemistry and nucleation kinetics in seven different solvents. One unsolvated form and four solvates of PNBA were obtained and one of the solvates was newly discovered. The nucleation behaviours and nucleation kinetics of PNBA in the seven solvents were studied and analyzed. Density functional theory (DFT) and solvation energy calculation were adopted to evaluate the strength of solute–solvent interactions. Vibrational spectroscopy combined with molecular simulation was applied to reveal the pre-assembly species in the solution. Based on these results, a comprehensive understanding of the relationship between molecular structure, crystal structure, solution chemistry and nucleation dynamics was proposed and discussed. It was found that the structural similarity between solution chemistry and crystal structure, the interaction between specific sites and the overall strength of solvation will jointly affect the nucleation process.

The recent developments at microdiffraction X-ray beamlines are making microcrystals of macromolecules appealing subjects for routine structural analysis. Microcrystal diffraction data collected at synchrotron microdiffraction beamlines may be radiation damaged with incomplete data per microcrystal and with unit-cell variations. A multi-stage data assembly method has previously been designed for microcrystal synchrotron crystallography. Here the strategy has been implemented as a Python program for microcrystal data assembly (PyMDA). PyMDA optimizes microcrystal data quality including weak anomalous signals through iterative crystal and frame rejections. Beyond microcrystals, PyMDA may be applicable for assembling data sets from larger crystals for improved data quality.

This new research, which involved both surface and aerial surveys, has revealed an enormous aggregation of whale sharks—the largest ever reported—with up to 420 individuals off the coast of the Yucatán Peninsula in Mexico.

The post Scientists discover the largest assembly of whale sharks ever recorded appeared first on Smithsonian Insider.

The Sun’s Active Region 1429 has been shooting off flares and coronal mass ejections since it rotated into Earth’s view on March 2, 2012. Two X-class flares have been released overnight, an X1.3 and an X5.4.

The post X-Class flares released by the Sun, March 6, captured by Atmospheric Imaging Assembly appeared first on Smithsonian Insider.

Archan Chakraborty, Wei-Cheng Lin, Yu-Tsun Lin, Kuang-Jing Huang, Pei-Yu Wang, Yi-Feng Chang, Hsiang-Iu Wang, Kung-Ting Ma, Chun-Yen Wang, Xuan-Rong Huang, Yen-Hsien Lee, Bi-Chang Chen, Ya-Ju Hsieh, Kun-Yi Chien, Tzu-Yang Lin, Ji-Long Liu, Li-Ying Sung, Jau-Song Yu, Yu-Sun Chang, and Li-Mei Pai

Under metabolic stress, cellular components can assemble into distinct membraneless organelles for adaptation. One such example is cytidine 5'-triphosphate synthase (CTPS), which forms filamentous structures under glutamine deprivation. We have previously demonstrated that histidine (His)-mediated methylation regulates the formation of CTPS filaments to suppress enzymatic activity and preserve the CTPS protein under Gln deprivation, which promotes cancer cell growth after stress alleviation. However, it remains unclear where and how these enigmatic structures are assembled. Using CTPS-APEX2-mediated in vivo proximity labeling, we found that SNAP29 regulates the spatiotemporal filament assembly of CTPS along the cytokeratin network in a keratin 8 (KRT8)-dependent manner. Knockdown of synaptosome-associated protein 29 (SNAP29) interfered with assembly and relaxed the filament-induced suppression of CTPS enzymatic activity. Furthermore, APEX2 proximity labeling of keratin 18 (KRT18) revealed a spatiotemporal association of SNAP29 with cytokeratin in response to stress. Super-resolution imaging suggests that during CTPS filament formation, SNAP29 interacts with CTPS along the cytokeratin network. This study links the cytokeratin network to the regulation of metabolism by compartmentalization of metabolic enzymes during nutrient deprivation.

Kasun Buddika, Ishara S. Ariyapala, Mary A. Hazuga, Derek Riffert, and Nicholas S. Sokol

Stressed cells downregulate translation initiation and assemble membrane-less foci termed stress granules (SGs). Extensively characterized in cultured cells, the existence of such structures in stressed adult stem cell pools remain poorly characterized. Here we report that Drosophila orthologs of mammalian SG components AGO1, ATX2, CAPRIN, eIF4E, FMRP, G3BP, LIN-28, PABP, and TIAR are enriched in adult intestinal progenitor cells where they accumulate in small cytoplasmic messenger ribonucleoprotein complexes (mRNPs). Treatment with sodium arsenite or rapamycin reorganized these mRNPs into large cytoplasmic granules. Formation of these intestinal progenitor stress granules (IPSGs) depended on polysome disassembly, led to translational downregulation, and was reversible. While canonical SG nucleators ATX2 and G3BP were sufficient for IPSG formation in the absence of stress, neither of them, nor TIAR, either individually or collectively, were required for stress-induced IPSG formation. This work therefore finds that IPSGs do not assemble via a canonical mechanism, raising the possibility that other stem cell populations employ a similar stress-response mechanism.

Aline A. Alves, Heloisa B. Gabriel, Maria J. R. Bezerra, Wanderley de Souza, Sue Vaughan, Narcisa L. Cunha-e-Silva, and Jack D. Sunter

Eukaryotic flagella are complex microtubule based organelles and in many organisms there are extra-axonemal structures present, including the outer dense fibres of mammalian sperm and the paraflagellar rod (PFR) of trypanosomes. Flagellum assembly is a complex process occurring across three main compartments, the cytoplasm, the transition fibre-transition zone, and the flagellum. It begins with translation of protein components, followed by their sorting and trafficking into the flagellum, transport to the assembly site and then incorporation. Flagella are formed from over 500 proteins; the principles governing axonemal component assembly are relatively clear. However, the coordination and sites of extra-axonemal structure assembly processes are less clear.

We have discovered two cytoplasmic proteins in T. brucei that are required for PFR formation, PFR assembly factors 1 and 2. Deletion of either PFR-AF1 or PFR-AF2 dramatically disrupted PFR formation and caused a reduction in the amount of major PFR proteins. The presence of cytoplasmic factors required for PFR formation aligns with the concept of processes occurring across multiple compartments to facilitate axoneme assembly and this is likely a common theme for extra-axonemal structure assembly.

Laurence Haren, Dorian Farache, Laurent Emorine, and Andreas Merdes

-tubulin is a major protein involved in the nucleation of microtubules in all eukaryotes. It forms two different complexes with proteins of the GCP family (gamma-tubulin complex proteins): -tubulin small complexes (TuSCs), containing -tubulin and GCPs 2 and 3, and -tubulin ring complexes (TuRCs), containing multiple TuSCs, in addition to GCPs 4, 5, and 6. Whereas the structure and assembly properties of TuSCs have been intensively studied, little is known about the assembly of TuRCs, and about the specific roles of GCPs 4, 5, and 6. Here, we demonstrate that two copies of GCP4 and one copy each of GCP5 and GCP6 form a salt-resistant sub-complex within the TuRC that assembles independently of the presence of TuSCs. Incubation of this sub-complex with cytoplasmic extracts containing TuSCs leads to the reconstitution of TuRCs that are competent to nucleate microtubules. In addition, we investigate sequence extensions and insertions that are specifically found at the amino-terminus of GCP6, and between the GCP6 grip1 and grip2 motifs, and we demonstrate that these are involved in the assembly or stabilization of the TuRC.

Ana Loncar, Sergio A. Rincon, Manuel Lera Ramirez, Anne Paoletti, and Phong T. Tran

To segregate the chromosomes faithfully during cell division, cells assemble a spindle that captures the kinetochores and pulls them towards opposite poles. Proper spindle function requires correct interplay between microtubule motors and non-motor proteins. Defects in spindle assembly or changes in spindle dynamics are associated with diseases like cancer or developmental disorders. Here we compared mitotic and meiotic spindles in fission yeast. We show that even though mitotic and meiotic spindles undergo the typical three phases of spindle elongation, they have distinct features. We found that the relative concentration of kinesin-14 Pkl1 is decreased in meiosis I compared to mitosis, while the concentration of kinesin-5 Cut7 remains constant. We identified the second kinesin-14 Klp2 and microtubule dynamics as factors necessary for proper meiotic spindle assembly. This work defines differences between mitotic and meiotic spindles in fission yeast, and provides prospect for future comparative studies.

Julian Chollet, Alexander Dünkler, Anne Bäuerle, Laura Vivero-Pol, Medhanie A. Mulaw, Thomas Gronemeyer, and Nils Johnsson

Yeast cells select the position of their new bud at the beginning of each cell cycle. The recruitment of the septins to this prospective bud site is one of the critical events in a complex assembly pathway that culminates in the outgrowth of a new daughter cell. Hereby, the septin-rods follow the high concentration of Cdc42_GTP that is generated by the focused localization of its GEF Cdc24. We show that shortly before budding Cdc24 not only activates Cdc42 but also transiently interacts with Cdc11, the septin subunit that caps both ends of the septin rods. Mutations in Cdc24 reducing the affinity to Cdc11 impair septin recruitment and decrease the stability of the polarity patch. The interaction between septins and Cdc24 thus reinforces bud assembly at sites where septin structures are formed. Once the septins polymerize into the ring, Cdc24 is found at the cortex of the bud and directs its further outgrowth from this position.

On June 7 the Sun unleashed an spectacular solar flare with a substantial coronal mass ejection. A large cloud of plasma mushroomed up, and while some parts fell back into the Sun, most rushed off into space. The first two segments of this video are seen through the Atmospheric Imaging Assembly aboard NASA's Solar Dynamics Observatory. The AIA was developed by Smithsonian scientists.

The post Spectacular June 7 solar flare seen through the Atmospheric Imaging Assembly aboard Solar Dynamics Observatory appeared first on Smithsonian Insider.

Aline A. Alves
Apr 15, 2020; 0:jcs.242271v1-jcs.242271
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Reform-a-nation Campaign/Docuseries Focuses on Injustice & Wrongful Convictions Like Anand Jon Alexander and Others in California and Beyond