Endophyte Inoculation and Elevated Potassium Supply on Productivity, Growth and Physiological Parameters of Spring Barley ( L.) Genotypes over Contrasting Seasons.

In recent years, recurrent droughts have significantly affected spring barley production, reducing the quantity and quality of grain. This study aims to identify genotype-specific traits and the drought resilience of six different L. (spring barley) genotypes, while also examining the potential of potassium application and fungal endophyte inoculation to mitigate the negative effects of dry periods during the growing season.

Threonine functionalized colloidal cadmium sulfide (CdS) quantum dots: The role of solvent and counterion in ligand induced chiroptical properties.

The functionalization of semiconductor nanocrystals, quantum dots (QDs), with small organic molecules has been studied extensively to gain better knowledge on how to tune the electronic, optical and chiroptical properties of QDs. Chiral QDs have progressively emerged as key materials in a vast range of applications including biosensing and biorecognition, imaging, asymmetric catalysis, optoelectronic devices, and spintronics. To engage the full potential of the unique properties of chiral nanomaterials and be able to prepare them with tailorable chiroptical characteristics, it is essential to understand how chirality is rendered from chiral molecular ligands at the surface of nanocrystals to the electronic states of QDs.

Apple juice and red wine induced mirror-image circular dichroism in quantum dots.

Juices, wines, and extracts from plants contain high concentrations of various chiral compounds such as carboxylic acids or sugars. Several prior studies reported the synthesis of metallic and semiconducting nanoparticles relying on components of complex biological solutions. Herein, we present preparation of chiral CdS and CdSe quantum dots (QDs) using apple juice and red wine via phase transfer ligand exchange.

The Potential of -Like Fungi for the Biological Protection of Cereals against Fungal Pathogens.

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are -like (like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses.

CdSe Quantum Dots Functionalized with Chiral, Thiol-Free Carboxylic Acids: Unraveling Structural Requirements for Ligand-Induced Chirality.

Functionalization of colloidal quantum dots (QDs) with chiral cysteine derivatives by phase-transfer ligand exchange proved to be a simple yet powerful method for the synthesis of chiral, optically active QDs regardless of their size and chemical composition. Here, we present induction of chirality in CdSe by thiol-free chiral carboxylic acid capping ligands (l- and d-malic and tartaric acids). Our circular dichroism (CD) and infrared experimental data showed how the presence of a chiral carboxylic acid capping ligand on the surface of CdSe QDs was necessary but not sufficient for the induction of optical activity in QDs.

Tuning the Sensitivity of Fluorescent Porphyrin Dimers to Viscosity and Temperature.

Conjugated porphyrin dimers have emerged as versatile viscosity-sensitive fluorophores that are suitable for quantitative measurements of microscopic viscosity by ratiometric and fluorescence lifetime-based methods, in a concentration-independent manner. Here, we investigate the effect of extended conjugation in a porphyrin-dimer structure on their ability to sense viscosity and temperature. We show that the sensitivity of the fluorescence lifetime to temperature is a unique property of only a few porphyrin dimers.

Partitioning of vessel resistivity in three liana species.

Vessels with simple perforation plates, found in the majority of angiosperms, are considered the evolutionarily most advanced conduits, least impeding the xylem sap flow. Nevertheless, when measured, their hydraulic resistivity (R, i.e.

Mechanothermally induced conformational switch of a porphyrin dimer in a polymer film.

Stretching a polymer film induces a conformational change (from the twisted to planar state) in the embedded porphyrin dimer, as evidenced by steady-state and time-resolved emission spectra.

Chirality Inversion of CdSe and CdS Quantum Dots without Changing the Stereochemistry of the Capping Ligand.

L-cysteine derivatives induce and modulate the optical activity of achiral cadmium selenide (CdSe) and cadmium sulfide (CdS) quantum dots (QDs). Remarkably, N-acetyl-L-cysteine-CdSe and L-homocysteine-CdSe as well as N-acetyl-L-cysteine-CdS and L-cysteine-CdS showed "mirror-image" circular dichroism (CD) spectra regardless of the diameter of the QDs. This is an example of the inversion of the CD signal of QDs by alteration of the ligand's structure, rather than inversion of the ligand's absolute configuration.

Unravelling the effect of temperature on viscosity-sensitive fluorescent molecular rotors.

Viscosity and temperature variations in the microscopic world are of paramount importance for diffusion and reactions. Consequently, a plethora of fluorescent probes have evolved over the years to enable fluorescent imaging of both parameters in biological cells. However, the simultaneous effect of both temperature and viscosity on the photophysical behavior of fluorophores is rarely considered, yet unavoidable variations in temperature can lead to significant errors in the readout of viscosity and .

Dual mode quantitative imaging of microscopic viscosity using a conjugated porphyrin dimer.

Microviscosity is of paramount importance in materials and bio-sciences. Fluorescence imaging using molecular rotors has emerged as a versatile tool to measure microviscosity, either using a fluorescence lifetime or a ratiometric signal of the rotor; however, only a limited number of blue-to-green-emitting fluorophores with both the lifetime and the ratiometric signal sensitivity to viscosity have been reported to date. Here we report a deep red emitting dual viscosity sensor, which allows both the ratiometric and the lifetime imaging of viscosity.

Supramolecular ssDNA templated porphyrin and metalloporphyrin nanoassemblies with tunable helicity.

Free-base and nickel porphyrin-diaminopurine conjugates were formed by hydrogen-bond directed assembly on single-stranded oligothymidine templates of different lengths into helical multiporphyrin nanoassemblies with highly modular structural and chiroptical properties. Large red-shifts of the Soret band in the UV/Vis spectroscopy confirmed strong electronic coupling among assembled porphyrin-diaminopurine units. Slow annealing rates yielded preferentially right-handed nanostructures, whereas fast annealing yielded left-handed nanostructures.

Ligand induced circular dichroism and circularly polarized luminescence in CdSe quantum dots.

Chiral thiol capping ligands L- and D-cysteines induced modular chiroptical properties in achiral cadmium selenide quantum dots (CdSe QDs). Cys-CdSe prepared from achiral oleic acid capped CdSe by postsynthetic ligand exchange displayed size-dependent electronic circular dichroism (CD) and circularly polarized luminescence (CPL). Opposite CPL signals were measured for the CdSe QDs capped with D- and L-cysteine.

Chiroptical properties, binding affinity, and photostability of a conjugated zinc porphyrin dimer complexed with left-handed Z-DNA and right-handed B-DNA.

We have studied the UV-vis absorption and chiroptical properties, binding affinity and photostability of a conjugated positively charged butadiyne-linked Zn(ii) porphyrin dimer bound to DNA sequence poly(dG-dC)2. Right-handed B-DNA, spermine-induced Z-DNA and Co(iii)-induced Z-DNA have been explored. Resonance light scattering (RLS) spectra showed formation of porphyrin aggregates in the presence of all DNA forms with the largest aggregates formed with B-DNA.

Chiroptical properties of anionic and cationic porphyrins and metalloporphyrins in complex with left-handed Z-DNA and right-handed B-DNA.

We report the chiroptical signature and binding interactions of cationic (meso-tetrakis(4-N-methylptridyl)porphyrin, 2HT4) and anionic (meso-tetrakis(4-sulfonatophenyl)porphyrin, 2HTPPS) porphyrins and their zinc(II) and nickel(II) derivatives (ZnT4, ZnTPPS, NiT4, and NiTPPS) with right-handed B-form and two forms of left-handed Z-form of alternating guanine-cytosine polydeoxynucleotide poly(dG-dC)2. NiTPPS is able to spectroscopically discriminate between spermine-induced Z-DNA and Co(III)-induced Z-DNA via new induced circular dichroism signal in the visible region of the electromagnetic spectrum.

Achiral CdSe quantum dots exhibit optical activity in the visible region upon post-synthetic ligand exchange with D- or L-cysteine.

Semiconductor cadmium selenide (CdSe) quantum dots (QDs) exhibited mirror-image circular dichroism (CD) spectra in the visible region (350-570 nm) after replacing the trioctylphosphine oxide/oleic acid ligands on achiral nanocrystals with D- and L-cysteines. Chiroptical properties of cysteine-capped CdSe QDs depend on their size and can be fine-tuned by changing the radius of QDs.

Formation and helicity control of ssDNA templated porphyrin nanoassemblies.

We report the formation of left- (M-helix) and right-handed (P-helix) nanoassemblies of a porphyrin-diaminopurine conjugate (Por-DAP) templated by a single stranded oligodeoxythymidine (dT40) via directional hydrogen bonding. The supramolecular helicity can be controlled by the ionic strength, Por-DAP : dT40 ratio, and annealing rate.

Highly sensitive and selective spectroscopic detection of mercury(II) in water by using pyridylporphyrin-DNA conjugates.

Single-labeled pyridylporphyrin-DNA conjugates are reported as highly sensitive and selective spectroscopic sensors for mercury(II) ions in water. The effects of chemical structure (thymine versus adenine), number of nucleotides (monomer versus octamer), and porphyrin metalation (Zn versus free base) on the sensitivity and selectivity of mercury(II) detection are explored. The results indicated that pyridylporphyrin rather than the nucleobase plays a crucial role in mercury(II) sensing, because porphyrin conjugates with both adenosine and thymidine exhibited excellent mercury(II) detection.

Porphyrin-DNA conjugates: porphyrin induced adenine-guanine homoduplex stabilization and interduplex assemblies.

DNA has found widespread uses as a nanosized scaffold for assembly of patterned multichomophoric nanostructures. Herein we report the synthesis, self-assembly, stability, and spectroscopic studies of short alternating non-self-complementary DNA sequences 5'-(dGdA)(4) and 5'-(dAdG)(4) with non-charged tetraarylporphyrins covalently linked to the 5' position of deoxyadenosine or deoxyguanosine via a phosphate or amide linker. The linker, the metal in the porphyrin coordination center, and the neighboring nucleobase have very distinct effects on the duplex formation of porphyrin-deoxyguanosine-deoxyadenosine oligodeoxynucleotides.

Sulfonated Ni(II)porphyrin improves the detection of Z-DNA in condensed and non-condensed BZB DNA sequences.

We report a very selective and sensitive spectroscopic detection of Z-DNA embedded in B-DNA in condensed as well as non-condensed DNA using anionic Ni(II) meso-tetrakis(4-sulphonatophenyl)porphyrin, NiTPPS. A combination of micromolar concentrations of Ni(II) and spermine(4+) allowed us to prepare left-handed Z-DNA in short oligonucleotides without DNA condensation. A strong induced circular dichroism (ICD) signal was observed in the visible absorption region when NiTPPS was added to BZ DNA (Z-DNA fragment located at the end of a B-DNA tract with one B/Z DNA junction) and BZB DNA (Z-DNA sequence embedded in B-DNA having two B/Z DNA junctions).

3,3'-diethylthiatricarbocyanine iodide: a highly sensitive chiroptical reporter of DNA helicity and sequence.

Using UV-vis absorption and circular dichroism (CD) spectroscopies, we explored the binding interactions of 3,3'-diethylthiatricarbocyanine iodide (Cy7) with polynucleotides of different sequences and helicity. CD showed to be a very diagnostic tool giving different spectroscopic chiroptical signatures for all explored DNA sequences upon Cy7 binding. Cy7 was able to spectroscopically discriminate between the right handed B-DNA of poly(dG-dC)(2) and its left handed Z-DNA counterpart induced by spermine or Co(III)hexamine via nearly opposite induced circular dichroic signal.

Z-DNA recognition in B-Z-B sequences by a cationic zinc porphyrin.

For the first time it has been shown by spectroscopic studies such as circular dichroism and UV/Vis that cationic zinc porphyrin serves as a selective spectroscopic sensor that is able to recognize short left-handed Z-DNA tracts embedded in the B-Z-B sequences.

Chiroptical detection of condensed nickel(II)-Z-DNA in the presence of the B-DNA via porphyrin exciton coupled circular dichroism.

Here, we report a highly sensitive and specific chiroptical detection method of condensed left-handed Z-DNA in the presence of canonical right-handed B-DNA. The selective formation of a left-handed cytosine-guanine oligonucleotide (CG ODN) in the presence of a right-handed adenine-thymine oligonucleotide (AT ODN) was induced by millimolar concentrations of NiCl(2) and confirmed by electronic circular dichroism. The nickel(II) induced B- to Z-DNA transition of the CG ODN was accompanied by the concurrent condensation of the Ni(II)-Z-DNA, as confirmed by resonance light scattering, transmission spectroscopy, and centrifugation.

Recognition of left-handed Z-DNA of short unmodified oligonucleotides under physiological ionic strength conditions.

The left-handed Z-DNA form of the short unmodified alternating guanine-cytosine oligonucleotides, 5'-(dGdC)(24) and 5'-(dGdC)(18), was selectively detected under physiological ionic strength and pH conditions using the anionic nickel(II) porphyrin, NiTPPS. No spectroscopic signal was observed for NiTPPS with any right-handed oligonucleotides under identical conditions. The 48mer 5'-(dGdC)(24) Z-form was detected at concentrations as low as 100nM.

Role of environmental factors on the structure and spectroscopic response of 5'-DNA-porphyrin conjugates caused by changes in the porphyrin-porphyrin interactions.

We have explored the utility, strength, and limitation of through-space exciton-coupled circular dichroism in determination of the secondary structure of optically active chromophoric nanoarrays using the example of end-capped porphyrin- and metalloporphyrin-oligodeoxynucleotide conjugates. We put special emphasis on the explanation of the origin and significance of the distinctive multiple bands in the CD spectra (trisignate and tetrasignate CD bands). Such CD profiles are often observed in chiral aggregates or multichromophoric arrays but have never before been studied in detail.