The title compound, C24H18FNO3, crystallizes in the monoclinic centrosymmetric space group P21/n and its mol­ecular conformation is stabilized via C—H⋯O intra­molecular inter­actions. The supra­molecular network mainly comprises C—H⋯O, C—H⋯F and C—H⋯π inter­actions, which contribute towards the formation of the crystal structure. The different inter­molecular inter­actions have been further analysed via Hirshfeld surface analysis and fingerprint plots.

The title compound, C19H16ClNO3S, consists of chloro­phenyl methyl­idene and di­hydro­benzo­thia­zine units linked to an acetate moiety, where the thia­zine ring adopts a screw-boat conformation. In the crystal, two sets of weak C—HPh⋯ODbt (Ph = phenyl and Dbt = di­hydro­benzo­thia­zine) hydrogen bonds form layers of mol­ecules parallel to the bc plane. The layers stack along the a-axis direction with inter­calation of the ester chains. The crystal studied was a two component twin with a refined BASF of 0.34961 (5). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (37.5%), H⋯C/C⋯H (24.6%) and H⋯O/O⋯H (16.7%) inter­actions. Hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry indicates that in the crystal, C—HPh⋯ODbt hydrogen bond energies are 38.3 and 30.3 kJ mol−1. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap. Moreover, the anti­bacterial activity of the title compound has been evaluated against gram-positive and gram-negative bacteria.

Exact and approximate mathematical formulas of equatorial aberration for powder diffraction data collected with an Si strip X-ray detector in continuous-scan integration mode are presented. An approximate formula is applied to treat the experimental data measured with a commercial powder diffractometer.

The X-chromosome-linked inhibitor of apoptosis protein (XIAP) is a multidomain protein whose main function is to block apoptosis by caspase inhibition. XIAP is also involved in other signalling pathways, including NF-κB activation and copper homeostasis. XIAP is overexpressed in tumours, potentiating cell survival and resistance to chemotherapeutics, and has therefore become an important target for the treatment of malignancy. Despite the fact that the structure of each single domain is known, the conformation of the full-length protein has never been determined. Here, the first structural model of the full-length XIAP dimer, determined by an integrated approach using nuclear magnetic resonance, small-angle X-ray scattering and electron paramagnetic resonance data, is presented. It is shown that XIAP adopts a compact and relatively rigid conformation, implying that the spatial arrangement of its domains must be taken into account when studying the interactions with its physiological partners and in developing effective inhibitors.

The preferred orientation growth characteristics and surface roughness of polycrystalline bis­muth (Bi) thin films fabricated on glass substrates using the molecular beam epitaxy method were investigated at temperatures ranging from 18 to 150°C. The crystallization and morphology were analyzed in detail and the polycrystalline metal film structure-zone model (SZM) was modified to fit the polycrystalline Bi thin film. The boundary temperature between Zone T and Zone II in the SZM shifted to higher temperatures with the increase in film thickness or the decrease of growth rate. Furthermore, the effect of the thickness and surface roughness on the transport properties was investigated, especially for Bi thin films in Zone II. A two-transport channels model was adopted to reveal the influence of the film thickness on the competition between the metallic surface states and the semiconducting bulk states, which is consistent with the results of Bi single-crystal films. Therefore, the polycrystalline Bi thin films are expected to replace the single-crystal films in the application of spintronic devices.

Characterizing and controlling the uniformity of nanoparticles is crucial for their application in science and technology because crystalline defects in the nanoparticles strongly affect their unique properties. Recently, ultra-short and ultra-bright X-ray pulses provided by X-ray free-electron lasers (XFELs) opened up the possibility of structure determination of nanometre-scale matter with Å spatial resolution. However, it is often difficult to reconstruct the 3D structural information from single-shot X-ray diffraction patterns owing to the random orientation of the particles. This report proposes an analysis approach for characterizing defects in nanoparticles using wide-angle X-ray scattering (WAXS) data from free-flying single nanoparticles. The analysis method is based on the concept of correlated X-ray scattering, in which correlations of scattered X-ray are used to recover detailed structural information. WAXS experiments of xenon nanoparticles, or clusters, were conducted at an XFEL facility in Japan by using the SPring-8 Ångstrom compact free-electron laser (SACLA). Bragg spots in the recorded single-shot X-ray diffraction patterns showed clear angular correlations, which offered significant structural information on the nanoparticles. The experimental angular correlations were reproduced by numerical simulation in which kinematical theory of diffraction was combined with geometric calculations. We also explain the diffuse scattering intensity as being due to the stacking faults in the xenon clusters.

This study made use of a recently developed combination of advanced methods to reveal the atomic structure of a disordered nanocrystalline zeolite using exit wave reconstruction, automated diffraction tomography, disorder modelling and diffraction pattern simulation. By applying these methods, it was possible to determine the so far unknown structures of the hydrous layer silicate RUB-6 and the related zeolite-like material RUB-5. The structures of RUB-5 and RUB-6 contain the same dense layer-like building units (LLBUs). In the case of RUB-5, these building units are interconnected via additional SiO4/2 tetrahedra, giving rise to a framework structure with a 2D pore system consisting of intersecting 8-ring channels. In contrast, RUB-6 contains these LLBUs as separate silicate layers terminated by silanol/sil­oxy groups. Both RUB-6 and RUB-5 show stacking disorder with intergrowths of different polymorphs. The unique structure of RUB-6, together with the possibility for an interlayer expansion reaction to form RUB-5, make it a promising candidate for interlayer expansion with various metal sources to include catalytically active reaction centres.

Several pathogenic bacteria utilize sialic acid, including host-derived N-acetylneuraminic acid (Neu5Ac), in at least two ways: they use it as a nutrient source and as a host-evasion strategy by coating themselves with Neu5Ac. Given the significant role of sialic acid in pathogenesis and host-gut colonization by various pathogenic bacteria, including Neisseria meningitidis, Haemophilus influenzae, Pasteurella multocida and Vibrio cholerae, several enzymes of the sialic acid catabolic, biosynthetic and incorporation pathways are considered to be potential drug targets. In this work, findings on the structural and functional characterization of CMP-N-acetylneuraminate synthetase (CMAS), a key enzyme in the incorporation pathway, from Vibrio cholerae are reported. CMAS catalyzes the synthesis of CMP-sialic acid by utilizing CTP and sialic acid. Crystal structures of the apo and the CDP-bound forms of the enzyme were determined, which allowed the identification of the metal cofactor Mg2+ in the active site interacting with CDP and the invariant Asp215 residue. While open and closed structural forms of the enzyme from eukaryotic and other bacterial species have already been characterized, a partially closed structure of V. cholerae CMAS (VcCMAS) observed upon CDP binding, representing an intermediate state, is reported here. The kinetic data suggest that VcCMAS is capable of activating the two most common sialic acid derivatives, Neu5Ac and Neu5Gc. Amino-acid sequence and structural comparison of the active site of VcCMAS with those of eukaryotic and other bacterial counterparts reveal a diverse hydrophobic pocket that interacts with the C5 substituents of sialic acid. Analyses of the thermodynamic signatures obtained from the binding of the nucleotide (CTP) and the product (CMP-sialic acid) to VcCMAS provide fundamental information on the energetics of the binding process.

Two commonly encountered bottlenecks in the structure determination of a protein by X-ray crystallography are screening for conditions that give high-quality crystals and, in the case of novel structures, finding derivatization conditions for experimental phasing. In this study, the phasing molecule 5-amino-2,4,6-triiodoisophthalic acid (I3C) was added to a random microseed matrix screen to generate high-quality crystals derivatized with I3C in a single optimization experiment. I3C, often referred to as the magic triangle, contains an aromatic ring scaffold with three bound I atoms. This approach was applied to efficiently phase the structures of hen egg-white lysozyme and the N-terminal domain of the Orf11 protein from Staphylococcus phage P68 (Orf11 NTD) using SAD phasing. The structure of Orf11 NTD suggests that it may play a role as a virion-associated lysin or endolysin.

Olfactomedins are a family of modular proteins found in multicellular organisms that all contain five-bladed β-propeller olfactomedin (OLF) domains. In support of differential functions for the OLF propeller, the available crystal structures reveal that only some OLF domains harbor an internal calcium-binding site with ligands derived from a triad of residues. For the myocilin OLF domain (myoc-OLF), ablation of the ion-binding site (triad Asp, Asn, Asp) by altering the coordinating residues affects the stability and overall structure, in one case leading to misfolding and glaucoma. Bioinformatics analysis reveals a variety of triads with possible ion-binding characteristics lurking in OLF domains in invertebrate chordates such as Arthropoda (Asp–Glu–Ser), Nematoda (Asp–Asp–His) and Echinodermata (Asp–Glu–Lys). To test ion binding and to extend the observed connection between ion binding and distal structural rearrangements, consensus triads from these phyla were installed in the myoc-OLF. All three protein variants exhibit wild-type-like or better stability, but their calcium-binding properties differ, concomitant with new structural deviations from wild-type myoc-OLF. Taken together, the results indicate that calcium binding is not intrinsically destabilizing to myoc-OLF or required to observe a well ordered side helix, and that ion binding is a differential feature that may underlie the largely elusive biological function of OLF propellers.

Anaerobic ammonium-oxidizing (anammox) bacteria play a key role in the global nitrogen cycle and in nitrogenous wastewater treatment. The anammox bacteria ultrastructure is unique and distinctly different from that of other prokaryotic cells. The morphological structure of an organism is related to its function; however, research on the ultrastructure of intact anammox bacteria is lacking. In this study, in situ three-dimensional nondestructive ultrastructure imaging of a whole anammox cell was performed using synchrotron soft X-ray tomography (SXT) and the total variation-based simultaneous algebraic reconstruction technique (TV-SART). Statistical and quantitative analyses of the intact anammox bacteria were performed. High soft X-ray absorption composition inside anammoxosome was detected and verified to be relevant to iron-binding protein. On this basis, the shape adaptation of the anammox bacteria response to iron was explored.

Time-resolved X-ray absorption spectroscopy (XAS) offers the possibility to monitor the state of materials during chemical reactions. While this technique has been established for transmission measurements for a number of years, XAS measurements in fluorescence mode are challenging because of limitations in signal collection as well as detectors. Nevertheless, measurements in fluorescence mode are often the only option to study complex materials containing heavy matrices or in samples where the element of interest is in low concentration. Here, it has been demonstrated that high-quality quick-scanning full extended X-ray absorption fine-structure data can be readily obtained with sub-second time resolution in fluorescence mode, even for highly diluted samples. It has also been demonstrated that in challenging samples, where transmission measurements are not feasible, quick fluorescence can yield significant insight in reaction kinetics. By studying the fast high-temperature oxidation of a reduced LaFe0.8Ni0.8O3 perovskite type, an example where the perovskite matrix elements prevent measurements in fluorescence, it is shown that it is now possible to follow the state of Ni in situ at a 3 s time resolution.

A complete method of comprehensive and quantitative evaluation of through-silicon via reliability using a highly sensitive phase-contrast X-ray microtomography was established. Quantitative characterizations include 3D local morphology and overall consistency of statistics.

Exact and approximate formulas for equatorial aberration of a continuous-scan Si strip detector are compared.

Neutron crystal structure analysis of hen egg-white lysozyme hydrogen/deuterium exchanged before crystallization were performed by the joint X-ray and neutron refinement. The differences in hydrogen/deuterium exchange behavior between this study and previous ones were observed.

The synthesis, characterization and study of structures from a series of bi­phenyls substituted at positions 3, 3', 4 and 4' with groups connected to the bi­phenyl core through oxygen atoms are presented here. The molecular conformation is extensively studied both in the solid as well as in the liquid state, and the effect of different actors (such as packing and chain length) on the torsion angle between aromatic rings is analyzed.

The crystal structure of gluconate 5-dehydrogenase from Lentibacter algarum is reported. It has high structural similarity to other gluconate 5-dehydrogenase proteins, demonstrating that this enzyme is highly conserved.

The structure of the Pseudomonas aeruginosa T6SS PldB immunity protein PA5086 is reported at 1.9 Å resolution. Comparison of PA5086 with its homologs PA5087 and PA5088 showed great similarities in sequence and structure, but vast divergences in electrostatic potential surfaces.

The true identity of the protein found in the crystals reported by Bondoc et al. [(2019), Acta Cryst. F75, 646–651] is given.

Mycobacterium tuberculosis produces glycogen (also known as α-glucan) to help evade human immunity. This pathogen uses the GlgE pathway to generate glycogen rather than the more well known glycogen synthase GlgA pathway, which is absent in this bacterium. Thus, the building block for this glucose polymer is α-maltose-1-phosphate rather than an NDP-glucose donor. One of the routes to α-maltose-1-phosphate is now known to involve the GlgA homologue GlgM, which uses ADP-glucose as a donor and α-glucose-1-phosphate as an acceptor. To help compare GlgA (a GT5 family member) with GlgM enzymes (GT4 family members), the X-ray crystal structure of GlgM from Mycobacterium smegmatis was solved to 1.9 Å resolution. While the enzymes shared a GT-B fold and several residues responsible for binding the donor substrate, they differed in some secondary-structural details, particularly in the N-terminal domain, which would be expected to be largely responsible for their different acceptor-substrate specificities.

The tiger reserves of Asia could support more than 10,000 wild tigers – three times the current number – if they are managed as large-scale […]

The post Tiger numbers could triple if large-scale landscapes are protected appeared first on Smithsonian Insider.

Tiny Antarctic marine creatures collected 100 years ago by British Royal Navy explorer Robert Falcon Scott are giving scientists new clues about polar environmental change.

The post Tiny creatures collected 100 years ago confirm accelerating carbon uptake in Antarctic Ocean appeared first on Smithsonian Insider.

Faced with insufficient time and inadequate library resources to tackle the problem on their own, they instead posted a catalog of specimen images to Facebook and turned to their network of colleagues for help.

The post Facebook friends help scientists quickly identify nearly 5,000 fish specimens collected in Guyana appeared first on Smithsonian Insider.

A new bacterial genome sequence could help researchers solve a mystery as to how microorganisms produce a highly toxic form of mercury.

The post New bacteria genome may help solve mystery of how methylmercury is made appeared first on Smithsonian Insider.

Smithsonian scientists have confirmed that chytridiomycosis, a rapidly spreading amphibian disease, has reached a site near Panama’s Darien region. This was the last area in the entire mountainous neotropics to be free of the disease. This is troubling news for the Panama Amphibian Rescue and Conservation Project, a consortium of nine U.S. and Panamanian institutions that aims to rescue 20 species of frogs in imminent danger of extinction.

The post Deadly amphibian disease detected in the last disease-free region of Central America appeared first on Smithsonian Insider.

Ecologists at the Smithsonian Environmental Research Center measure the growth rate of sedge grass in a brackish Chesapeake Bay marsh. Fed a diet rich in […]

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New research by a team of astronomers found that planets smaller than Neptune are located around a wide variety of stars, including those with fewer heavy elements than the Sun.

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A July 12 news alert from NASA indicates a X1.4 class solar flare erupted from the center of the Sun, peaking July 12 at 12:52 P.M.

The post Coronal mass ejection from July 12 solar flare headed toward Earth; minor geomagnetic storm activity predicted appeared first on Smithsonian Insider.

A rare Longman’s beaked whale found stranded on the Hawaiian island of Maui in 2010 has scientists in Hawaii on the alert for a deadly disease known as morbillivirus which can lead to high mortality rates in dolphins and other marine mammals.

The post Rare whale beached in Hawaii infected with deadly marine-mammal virus appeared first on Smithsonian Insider.

A new study of microorganisms living on the skin and in the intestines of North America vultures (black and turkey vultures) has turned up a […]

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Through sheer coincidence, two Smithsonian researchers at the National Zoological Park have discovered that 18 percent of the white-tailed deer population in the Eastern United […]

The post Smithsonian study reveals white-tailed deer in eastern U.S. are infected with a malaria parasite appeared first on Smithsonian Insider.

Crustaceans that thrive in the vastness of the open ocean have no place to hide from their predators. Consequently, many creatures that live at depths […]

The post Tiny ocean crustaceans wear invisibility cloak of living bacteria appeared first on Smithsonian Insider.

Some of Hong Kong’s most disturbed and pristine marine environments were the recent focus of an intense 10-day MarineGEO survey of living organisms by a […]

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Very early on, cockroach moms found out maternal care gave their offspring a better chance at survival. The cockroach parenting method—which includes feeding, guarding and […]

The post Helicopter cockroach moms have protected their young for millions of years appeared first on Smithsonian Insider.

In the early 20th century, Canada geese were considered endangered in the U.S. So in the 1950s and 1960s, birds from the Midwest were released […]

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A full 94 percent of the dead zones in the world’s oceans lie in regions expected to warm at least 2 degrees Celsius by the […]

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As enjoyable as scientific work can be, says entomologist Dave Roubik, its greatest satisfactions are often long delayed. He gives the best example from his career: a seventeen-year study that finally helped to change our understanding of the notorious "killer bees."

The post Long-term killer bee study in tropics yields unexpected discovery: invasive killer bees are good for the native bees appeared first on Smithsonian Insider.

The state's online registration for Covered California has been up for a couple of weeks, and reaction has been mixed.

Steve Julian: Business analyst, Mark Lacter, what's your take on how well Californians are getting into the Affordable Care Act?

Mark Lacter: It's hard to get a good read, Steve, because it's hard to measure the success of what is really a new marketplace.  If you're basing it on the number of unique visitors coming to the Covered California website, well, then the program clearly has attracted lots of interest - they had almost a million visitors during the first week of eligibility.  But, maybe a better measure would be the number of people whose applications actually have been received by the insurance companies that are going to handle the claims.  If that's your measuring stick, then the numbers have been far smaller so far.  Now, it's worth pointing out that California - and particularly L.A. County - have a higher percentage of households without insurance than other parts of the nation, and so you'd expect there to be lots of interest.

Julian: So the question, then, is how many folks turn into actual policyholders paying actual premiums each month.

Lacter: The truth is nobody knows, which is why state officials want to sign up as many people as possible in the early going when the program is getting so much attention.  This is especially true for younger and healthier people who are needed to help offset the cost of caring for older and sicker people.

Julian: And, that's also why any computer glitch can be such a headache...

Lacter: That's right.  Covered California did run into problems in the early going, but everybody agrees that things are going much better than the federal website, which is the default site used by folks in states that don't have their own program to oversee the health care laws.  That federal site has been an utter disaster.  So, by comparison, California is ahead of the game.

Julian: It's a work in progress, even here.

Lacter: Very much so.  The California website still doesn't have a way for enrollees to find out which doctors and hospitals are included in each health plan.  And, that's a big deal because  insurance companies are limiting the options available as a way of keeping premiums low.  So, it's possible that the doctor you had been using for your individual insurance plan will not be on the list of doctors that can be used for one of the cheaper plans.  Of course, for someone who doesn't have any health coverage, none of that is likely to matter.

Julian: And then, there's the continued threat of a U.S. default...

Lacter: You know, Steve, this is like watching the beginning of a bad traffic accident in slow motion - and we're all pretty helpless to do anything about it.  And, so are the financial markets, which are moving back and forth not based on what's going on with the economy or with any industry, but on the latest press conference out of Washington.  One thing we do know is that if the nation does go into quote-unquote default - and we're not even sure what that might mean - but if Wall Street and somehow declares this a major crisis, it's going to be bad.

Julian: Who gets hit?

Lacter: It'll impact anyone who has a retirement account, any business wanting to borrow money, and potentially it's going to impact the budgeting of the state.  You know, one of the things we were reminded of during the Great Recession was how reliant California has been on higher-income individuals who make a lot of their money through the stock market and other investments.  So, when those folks do well - as they have been over the last year - the state coffers will do well.  And when they don't, as was the case in 2008 and 2009, the state takes a huge hit because there's not enough tax dollars coming in.  Gov. Brown and others have tried to lessen the reliance on those top tiers - so far without success.

Julian: And the state's budget situation is so much better than it was a year or two ago.

Lacter: That's the real pity.  And, even if the House and Senate reach a temporary agreement on the debt ceiling, it's just a matter of weeks or months before another deadline crops up - and more uncertainty for the financial markets.  I guess Chick Hearn would have called this nervous time.

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Latinus 9333 is the Latin translation of the so-called Tacuinum sanitatis, a medieval handbook on wellness written in Arabic by the 11th-century physician ibn Butlan. It deals with factors influencing human health: from the air, the environment and food, to physical exercise and sexual activity.

The post Medieval book is important resource for how plants were once collected, treated and used appeared first on Smithsonian Insider.

For the first time, a new public database will link genetic data with records of where and when the samples it was taken from were […]

The post A first: New website reveals origin of genetic samples and date collected appeared first on Smithsonian Insider.

The new copper(II) complex [CuLCl2]2, where L is a product of Schiff base condensation between methyl­amine and 2-pyridine­carbaldehyde, is built of discrete centrosymmetric dimers.

The new copper(II) complex, namely, di-μ-chlorido-bis{chlorido[methyl(pyridin-2-ylmethylidene)amine-κ2N,N']copper(II)}, [Cu2Cl4(C7H8N2)2], (I), with the ligand 2-pyridylmethyl-N-methylimine (L, a product of Schiff base condensation between methylamine and 2-pyridinecarbaldehyde) is built of discrete centrosymmetric dimers. The coordination about the CuII ion can be described as distorted square pyramidal. The base of the pyramid consists of two nitrogen atoms from the bidentate chelate L [Cu—N = 2.0241 (9), 2.0374 (8) Å] and two chlorine atoms [Cu—Cl = 2.2500 (3), 2.2835 (3) Å]. The apical position is occupied by another Cl atom with the apical bond being significantly elongated at 2.6112 (3) Å. The trans angles of the base are 155.16 (3) and 173.79 (2)°. The Cu...Cu separation in the dimer is 3.4346 (3) Å. In the crystal structure, the loosely packed dimers are arranged in stacks propagating along the a axis. The X-band polycrystalline 77 K EPR spectrum of (I) demonstrates a typical axial pattern characteristic of mononuclear CuII complexes. Compound (I) is redox active and shows a cyclic voltammetric response with E1/2 = −0.037 V versus silver–silver chloride electrode (SSCE) assignable to the reduction peak of CuII/CuI in methanol as solvent.

An efficient synthesis of 1-aryl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazo­tization of 3-amino-4-aryl­amino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The mol­ecules of 1-phenyl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds, while the structures of 1-(2-methyl­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the mol­ecules into simple chains, which are further linked into sheets by π-stacking inter­actions in (II) but not in (III). In the structure of 1-(4-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. When com­pound (II) was exposed to a strong acid in methanol, qu­anti­tative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hy­droxy-1-(2-methyl­phen­yl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the mol­ecules are linked by paired O—H⋯O hydrogen bonds to form centrosymmetric dimers.

An operationally simple and time-efficient approach has been developed for the synthesis of racemic N-substituted 3-(2-aryl-2-oxoeth­yl)-3-hy­droxy­indolin-2-ones by a piperidine-catalysed aldol reaction between aryl methyl ketones and N-alkyl­isatins. These aldol products were used successfully as strategic inter­mediates for the preparation of N-substituted (E)-3-(2-hetaryl-2-oxo­ethyl­idene)indolin-2-ones by a stereoselective dehydration reaction under acidic conditions. The products have all been fully characterized by 1H and 13C NMR spectroscopy, by mass spectrometry and, for a representative selection, by crystal structure analysis. In each of (RS)-1-benzyl-3-hy­droxy-3-[2-(4-meth­oxy­phen­yl)-2-oxoeth­yl]indolin-2-one, C24H21NO4, (Ic), and (RS)-1-benzyl-3-{2-[4-(di­methyl­amino)­phen­yl]-2-oxoeth­yl}-3-hy­droxy­indolin-2-one, C25H24N2O3, (Id), inversion-related pairs of mol­ecules are linked by O—H⋯O hydrogen bonds to form R22(10) rings, which are further linked into chains of rings by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds in (Ic) and by C—H⋯π(arene) hydrogen bonds in (Id). The mol­ecules of (RS)-1-benzyl-3-hy­droxy-3-[2-oxo-2-(pyridin-4-yl)eth­yl]indolin-2-one, C22H18N2O3, (Ie), are linked into a three-dimensional framework structure by a combination of O—H⋯N, C—H⋯O and C—H⋯π(arene) hydrogen bonds. (RS)-3-[2-(Benzo[d][1,3]dioxol-5-yl)-2-oxoeth­yl]-1-benzyl-3-hy­droxy­indolin-2-one, C24H19NO5, (If), crystallizes with Z' = 2 in the space group Poverline{1} and the mol­ecules are linked into com­plex sheets by a combination of O—H⋯O, C—H⋯O and C—H⋯π(arene) hydro­gen bonds. In each of (E)-1-benzyl-3-[2-(4-fluoro­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C23H16FNO2, (IIa), and (E)-1-benzyl-3-[2-oxo-2-(thiophen-2-yl)ethylidene]indolin-2-one, C21H15NO2S, (IIg), the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond, while those of (E)-1-benzyl-3-[2-oxo-2-(pyridin-4-yl)ethyl­idene]indolin-2-one, C22H16N2O2, (IIe), are linked by three C—H⋯O hydrogen bonds to form sheets which are further linked into a three-dimensional structure by C—H⋯π(arene) hydrogen bonds. There are no hydrogen bonds in the structures of either (E)-1-benzyl-3-[2-(4-meth­oxy­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C24H19NO3, (IIc), or (E)-1-benzyl-5-chloro-3-[2-(4-chloro­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C23H15Cl2NO2, (IIh), but the mol­ecules of (IIh) are linked into chains of π-stacked dimers by a combination of C—Cl⋯π(arene) and aromatic π–π stacking inter­actions.

Christopher R. Mahone
Apr 8, 2020; 133:jcs237057-jcs237057
CELL SCIENCE AT A GLANCE

Full Text:

The molecular mechanism used by many bacteria to kill neighboring cells has redundancy built into its genetic makeup, which could allow for the mechanism to be expressed in different environments, say researchers at Penn State and the University of Wisconsin-Madison. Their new study provides insights into the molecular mechanisms of competition among bacteria. "Many organisms, including humans, acquire bacteria from their environment," said Tim Miyashiro, a biochemist and molecular biologist at Penn State and the leader of the research team. "These bacteria can contribute to functions within the host organism, like how our gut bacteria help us digest food. We're interested in the interactions among bacteria cells, and between bacteria and their hosts, to better understand these mutually beneficial symbiotic relationships." Cells of the bioluminescent bacteria Vibrio fisheri take up residence in the light organ of newly hatched bobtail squid. At night, the bacteria produce a blue glow that researchers believe obscures a squid's silhouette and helps protect it from predators. The light organ has pockets, or crypts, in the squid's skin that provide nutrients and a safe environment for the bacteria. "When the squid hatches, it doesn't yet have any bacteria in its light organ," said Miyashiro. "But bacteria in the environment quickly colonize the squid's light organ." Some of these different bacteria strains can coexist, but others can't. "Microbial symbioses are essentially universal in animals, and are crucial to the health and development of both partners," says Irwin Forseth, a program director in the National Science Foundation's Division of Integrative Organismal Systems, which funded the research. "The results from this study highlight the role small genetic changes can play in microbe interactions. Increased understanding will allow us to better predict organisms' performance in changing environments."

Image credit: Andrew Cecere