Isolation of Soil Microorganisms Using iChip Technology.

The iChip isolation technique uses an in-situ isolation device that increases the cultivability of previously unculturable microorganisms. Microorganisms are an important source of novel chemistries and potentially bioactive molecules. However, only 1% of environmental microorganisms can be cultured using conventional laboratory methods.

Bioassay-Guided Identification of Natural Products for Biocontrol by Thin Layer Chromatography-Direct Bioautography.

Thin layer chromatography-direct bioautography (TLC-DB) is a well-established bioassay used to separate and identify natural products (NPs) that are antagonistic against a target pathogen. It is a rapid, inexpensive, and simple option for the bioassay-guided isolation and identification of NPs that hinges on separation by TLC coupled with the direct application of a target pathogen to examine bioactivity. It is typically used for the analysis of bioactive plant extracts, detecting inhibitory activity against bacteria, fungi, and enzymes.

Elucidating the Role of Optical Activity of Polymers in Protein-Polymer Interactions.

Proteins are biomolecules with potential applications in agriculture, food sciences, pharmaceutics, biotechnology, and drug delivery. Interactions of hydrophilic and biocompatible polymers with proteins may impart proteolytic stability, improving the therapeutic effects of biomolecules and also acting as excipients for the prolonged storage of proteins under harsh conditions. The interactions of hydrophilic and stealth polymers such as poly(ethylene glycol), poly(trehalose), and zwitterionic polymers with various proteins are well studied.

Uncovering the mechanism of selective stabilization of high-energy diastereoisomers via inclusion.

Unlabelled: Supramolecular systems may be used to stabilize otherwise unstable isomers to find alternative synthetic pathways. It has been reported that cucurbit[8]uril can stabilize -I and -II Cu cyclam, whereas -III is the only non-substituted Cu cyclam diastereoisomer found outside of the host molecule experimentally. Quantum chemistry methods can provide valuable insight into the intermolecular interactions involved in these inclusion complexes.

Photophysical Properties of Donor-Acceptor Stenhouse Adducts and Their Inclusion Complexes with Cyclodextrins and Cucurbit[7]uril.

Donor-acceptor Stenhouse adducts (DASAs) are a novel class of solvatochromic photoswitches with increasing importance in photochemistry. Known for their reversibility between open triene and closed cyclized states, these push-pull molecules are applicable in a suite of light-controlled applications. Recent works have sought to understand the DASA photoswitching mechanism and reactive state, as DASAs are vulnerable to irreversible "dark switching" in polar protic solvents.

Synthesis of Oligo(1,8-pyrenylene)s: A Series of Functional Molecular Liquids.

A monomer-through-pentamer series of oligo(1,8-pyrenylene)s was synthesized using a two-step iterative synthetic strategy. The trimer, tetramer, and pentamer are mixtures of atropisomers that interconvert slowly at room temperature (as shown by variable-temperature NMR analysis). They are liquids well below room temperature, as indicated by POM, DSC and SWAXS analysis.

Detection and Identification of Reaction Intermediates in the Photorearrangement of Pyridazine -Oxide: Discrepancies between Experiment and Theory.

Photolysis of pyridazine -oxide (PNO) results in the detection of a complex series of transient phenomena. On the ultrafast (fs) timescale, we could detect the decay of the first singlet excited state of PNO and the formation of a short-lived transient species, which, based on its time-resolved resonance Raman (TR) spectrum, we assign to oxaziridine 1,2-diaza-7-oxa-bicyclo[4.1.

Advances in Light-Emitting Dendrimers.

The design of dendrimers with various chromophores has attracted significant attention in light of the dual effect of the luminescence of the chromophores and the morphology of the synthesized dendrimers. Recent developments in this field stem from their wide potential applications, including organic light-emitting diodes, photonic switches and upconversion lasers, as well as sensors and electronic devices. The focus of this comprehensive review is on the design and properties of various classes of light-harvesting dendrimeric materials.

Factors Affecting the Formation of 2:1 Host:Guest Inclusion Complexes of 2-[(R-Phenyl)amine]-1,4-naphthalenediones (PAN) in β- and γ-Cyclodextrins.

The molecular hosts cyclodextrins form inclusion complexes with a wide variety of guests, resulting in complexes with various host:guest stoichiometries. In the case of a series of 19 1,4-naphthoquinolines as guests with either β- or γ-cyclodextrin studied using electrospray mass spectroscopy, in most cases only 1:1 complexes were observed, with 2:1 host:guest complexes observed in just 6 out of 38 host:guest combinations. It is shown that these higher-order complexes were observed only in the case of small (or no) electronically withdrawing substituents, and were much less likely in the case of the larger γ-cyclodextrin host.

Structure-Binding Effects: Comparative Binding of 2-Anilino-6-naphthalenesulfonate by a Series of Alkyl- and Hydroxyalkyl-Substituted β-Cyclodextrins.

Cyclodextrins (CDs) are the most widely used organic hosts for the inclusion of guest molecules. CDs can be readily modified through substitutions of the hydroxyl groups, and these modified CDs can have different host binding properties compared to those of parent CDs. However, only relatively few systematic studies of the effects of chemical substitution on CD binding ability have been reported thus far.

In vitro assessment of endocrine disrupting potential of naphthenic Acid fractions derived from oil sands-influenced water.

Oil sands-influenced process waters have been observed to cause reproductive effects and to induced CYP1A activity in fishes; however, little progress has been made in determining causative agents. Naphthenic acids (NAs) are the predominant organic compounds in process-affected waters, but due to the complexity of the mixture, it has been difficult to examine causal linkages in fishes. The aim of this study was to use in vitro assays specific to reproductive and CYP1A mechanisms to determine if specific acid extractable fractions of NAs obtained from oil sands-influenced water are active toward reproductive processes or interact with the Ah receptor responsible for CYP1A activity.

Immunotoxic effects of oil sands-derived naphthenic acids to rainbow trout.

Naphthenic acids are the major organic constituents in waters impacted by oil sands. To investigate their immunotoxicity, rainbow trout (Oncorhynchus mykiss) were injected with naphthenic acids extracted from aged oil sands tailings water. In two experiments, rainbow trout were injected intraperitoneally with 0, 10, or 100 mg/kg of naphthenic acids, and sampled after 5 or 21 d.

Hydrogen bonding of excited states in supramolecular host-guest inclusion complexes.

Host-guest inclusion complexes represent an important type of supramolecular structure, one which finds widespread applications in diverse areas including separations science, the food industry, molecular sensors and optical devices. There are several driving forces for the formation of such inclusion complexes in solution; one of the most important is hydrogen bonding between the guest and host molecules. The nature or strength of the hydrogen bonding may change upon electronic excitation of the guest, for example during fluorescence studies or when the inclusion complex is used as an optical sensor.

Fluorescence-based comparative binding studies of the supramolecular host properties of PAMAM dendrimers using anilinonaphthalene sulfonates: unusual host-dependent fluorescence titration behavior.

This work describes the fluorescence enhancement of the anilinonaphthalene sulfonate probes 1,8-ANS, 2,6-ANS, and 2,6-TNS via complexation with PAMAM dendrimer hosts of Generation 4, 5 and 6. The use of this set of three very closely related probes allows for comparative binding studies, with specific pairs of probes differing only in shape (1,8-ANS and 2,6-ANS), or in the presence of a methyl substituent (2,6-TNS vs. 2,6-ANS).

The use of coumarins as environmentally-sensitive fluorescent probes of heterogeneous inclusion systems.

Coumarins, as a family of molecules, exhibit a wide range of fluorescence emission properties. In many cases, this fluorescence is extremely sensitive to the local environment of the molecule, especially the local polarity and microviscosity. In addition, coumarins show a wide range of size, shape, and hydrophobicity.

A cucurbit[6]uril analogue: host properties monitored by fluorescence spectroscopy.

This paper describes the host properties of a new cucurbit[6]uril analogue, studied by fluorescence and 1H NMR spectroscopy. This host has an elongated cavity with oval-shaped portals. It is intrinsically fluorescent, and more importantly, this fluorescence is sensitive to guest encapsulation, allowing for the study of the inclusion of nonfluorescent guests by fluorescence spectroscopy.

Molecular-recognition properties of a water-soluble cucurbit[6]uril analogue.

The molecular-recognition properties of the cucurbit[6]uril analogue (1) in aqueous buffer (sodium acetate, 50 mM, pH 4.74, 25 degrees C) toward a variety of guests including alkanediamines (6-12), aromatics (14-32), amino acids (33-36), and nucleobases (37-42) were studied by fluorescence spectroscopy. For the alkanediamines studied (H2N(CH)nNH2, n = 6, 7, 8, 9, 10, 11, 12), the association constants increase as the length of the alkane (n) is increased.

Amination of pyridylketenes: experimental and computational studies of strong amide enol stabilization by the 2-pyridyl group.

Laser flash photolyses of 2-, 3-, and 4-diazoacetylpyridines 8 give the corresponding pyridylketenes 7 formed by Wolff rearrangements, as observed by time-resolved infrared spectroscopy, with ketenyl absorptions at 2127, 2125, and 2128 cm(-1), respectively. Photolysis of 2-, 3-, and 4-8 in CH(3)CN containing n-BuNH(2) results in the formation of two transients in each case, as observed by time-resolved IR and UV spectroscopy. The initial transients are assigned as the ketenes 7, and this is confirmed by IR measurements of the decay of the ketenyl absorbance.