Effect of ClAlPcS(2) photodynamic and sonodynamic therapy on HeLa cells

Photodynamic therapy (PDT) uses photosensitive substance to provoke a cytotoxic reaction causing a cell damage or cell death. The substances, photosensitizers, are usually derivates of porphyrine or phtalocyanine. Photosensitizers must be activated by light in order to produce reactive oxygen species, mainly singlet oxygen. Sonodynamic therapy (SDT) utilizes ultrasound to enhance a cytotoxic effects of compounds called sonosensitizers. In this study we investigated photodynamic and sonodynamic effect of chloraluminium phtalocyanine disulfonate (ClAlPcS(2)) on HeLa cells. DNA damage, cell viability and reactive oxygen species (ROS) production were assessed to find whether the combination of PDT and SDT inflicts HeLa cells more than PDT alone. We found that the combined therapy increases DNA fragmentation, enhances ROS production and decreases cell survival. Our results indicate that ClAlPcS(2) can act as a sonosentitiser and combined with PDT causes more irreversible changes to the cells resulting in cell death than PDT alone.

A secretion biosensor for monitoring Sec-dependent protein export in Corynebacterium glutamicum

BACKGROUND

In recent years, the industrial workhorse Corynebacterium glutamicum has gained increasing interest as a host organism for the secretory production of heterologous proteins. Generally, the yield of a target protein in the culture supernatant depends on a multitude of interdependent biological and bioprocess parameters which have to be optimized. So far, the monitoring of such optimization processes depends on the availability of a direct assay for the respective target protein that can be handled also in high throughput approaches. Since simple assays, such as standard enzymatic activity assays, are not always at hand, the availability of a general protein secretion biosensor is highly desirable.

RESULTS

High level secretion of proteins via the Sec protein export pathway leads to secretion stress, a phenomenon that is thought to be caused by the accumulation of incompletely or misfolded proteins at the membrane-cell envelope interface. We have analyzed the transcriptional responses of C. glutamicum to the secretory production of two different heterologous proteins and found that, in both cases, the expression of the gene encoding a homologue of the extracytosolic HtrA protease was highly upregulated. Based on this finding, a C. glutamicum Sec secretion biosensor strain was constructed in which the htrA gene on the chromosome was replaced by the eyfp gene. The fluorescence of the resulting reporter strain responded to the secretion of different heterologous proteins (cutinase from Fusarium solani pisi and alkaline phosphatase PhoA from Escherichia coli) in a dose-dependent manner. In addition, three differently efficient signal peptides for the secretory production of the cutinase could be differentiated by the biosensor signal. Furthermore, we have shown that an efficient signal peptide can be separated from a poor signal peptide by using the biosensor signal of the respective cells in fluorescence activated cell sorting experiments.

CONCLUSIONS

We have succeeded in the construction of a C. glutamicum biosensor strain that allows for the monitoring of Sec-dependent secretion of heterologous proteins in a dose-dependent manner, independent of a direct assay for the desired target protein.

Optical response of the Cu2 S2 diamond core in Cu2II(NGuaS)2 Cl2

Density functional theory (DFT) and time-dependent DFT calculations are presented for the dicopper thiolate complex Cu2 (NGuaS)2 Cl2 [NGuaS=2-(1,1,3,3-tetramethylguanidino) benzenethiolate] with a special focus on the bonding mechanism of the Cu2 S2 Cl2 core and the spectroscopic response. This complex is relevant for the understanding of dicopper redox centers, for example, the CuA center. Its UV/Vis absorption is theoretically studied and found to be similar to other structural CuA models. The spectrum can be roughly divided in the known regions of metal d-d absorptions and metal to ligand charge transfer regions. Nevertheless the chloride ions play an important role as electron donors, with the thiolate groups as electron acceptors. The bonding mechanism is dissected by means of charge decomposition analysis which reveals the large covalency of the Cu2 S2 diamond core mediated between Cu dz2 and S-S π and π* orbitals forming Cu-S σ bonds. Measured resonant Raman spectra are shown for 360- and 720-nm excitation wavelength and interpreted using the calculated vibrational eigenmodes and frequencies. The calculations help to rationalize the varying resonant behavior at different optical excitations. Especially the phenylene rings are only resonant for 720 nm. © 2016 Wiley Periodicals, Inc.

Intravitreal anti-vascular endothelial growth factor combined with half-fluence photodynamic therapy for choroidal neovascularization in chronic central serous chorioretinopathy

PurposeTo evaluate the results of indocyanine green angiography (ICGA)-guided verteporfin photodynamic therapy (PDT) with half-fluence rate combined with intravitreal application of anti-VEGF in treating choroidal neovascularization (CNV) in chronic central serous chorioretinopathy (CSCR).Patients and methodsIn this retrospective cohort study 17 consecutive patients with secondary CNV due to chronic CSCR had their diagnosis verified with fluorescein angiography (FA) and ICGA at baseline. All eyes received either intravitreal ranibizumab (IVR) or bevacizumab (IVB). On the consecutive day following the initial IVR/IVB treatment, ICGA-guided verteporfin (6 mg/m(2)) PDT with half-fluence rate (25 J/cm(2)) was performed on every patient. IVR or IVB was rescheduled on a pro re nata regimen. Main outcome measures were changes in visual acuity (VA) according to the ETDRS letter score and changes in the central foveal thickness (CFT).ResultsBest-corrected VA at baseline was 65.6 letters (±6.7; n=17) according to the ETDRS letter score. At 12 months, mean ETDRS letter score improved to 71.2 letters (P=0.34). CFT was 309 μm and decreased to 216 μm at month 12 control (P=0.0004). Nine eyes (52.9%) received additional treatment with IVR/IVB due to recurrence of subretinal fluid, with an overall mean number of IVR/IVB treatment of 1.8±3.6 per patient with no systemic side effects during 12 months' follow-up.ConclusionsIVR or IVB combined with ICGA-guided half-fluence PDT with verteporfin is effective in treating CNV in chronic CSCR, with choroidal hyperpermeability in ICGA, resulting in stable vision and significant reduction of CFT.

Nonperturbative shell-model interactions from the in-medium similarity renormalization group

We present the first ab initio construction of valence-space Hamiltonians for medium-mass nuclei based on chiral two- and three-nucleon interactions using the in-medium similarity renormalization group. When applied to the oxygen isotopes, we find experimental ground-state energies are well reproduced, including the flat trend beyond the drip line at (24)O. Similarly, natural-parity spectra in (21,22,23,24)O are in agreement with experiment, and we present predictions for excited states in (25,26)O. The results exhibit a weak dependence on the harmonic-oscillator basis parameter and reproduce spectroscopy within the standard sd valence space.

Electronic screening-enhanced hole pairing in two-leg spin ladders studied by high-resolution resonant inelastic x-ray scattering at Cu M edges

We study the electronic screening mechanisms of the effective Coulomb on-site repulsion in hole-doped Sr(14)Cu(24)O(41) compared to undoped La(6)Ca(8)Cu(24)O(41) using polarization dependent high-resolution resonant inelastic x-ray scattering at Cu M edges. By measuring the energy of the effective Coulomb on-site repulsion and the spin excitations, we estimate superexchange and hopping matrix element energies along rungs and legs, respectively. Interestingly, hole doping locally screens the Coulomb on-site repulsion reducing it by as much as 25%. We suggest that the increased ratio of the electronic kinetic to the electronic correlation energy contributes to the local superexchange mediated pairing between holes.

SoxR as a single-cell biosensor for NADPH-consuming enzymes in Escherichia coli

An ultra-high-throughput screening system for NADPH-dependent enzymes, such as stereospecific alcohol dehydrogenases, was established. It is based on the [2Fe-2S] cluster-containing transcriptional regulator SoxR of Escherichia coli that activates expression of soxS in the oxidized but not in the reduced state of the cluster. As SoxR is kept in its reduced state by NADPH-dependent reductases, an increased NADPH demand of the cell counteracts SoxR reduction and increases soxS expression. We have taken advantage of these properties by placing the eyfp gene under the control of the soxS promoter and analyzed the response of E. coli cells expressing an NADPH-dependent alcohol dehydrogenase from Lactobacillus brevis (LbAdh), which reduces methyl acetoacetate to (R)-methyl 3-hydroxybutyrate. Under suitable conditions, the specific fluorescence of the cells correlated with the substrate concentration added and with LbAdh enzyme activity, supporting the NADPH responsiveness of the sensor. These properties enabled sorting of single cells harboring wild-type LbAdh from those with lowered or without LbAdh activity by fluorescence-activated cell sorting (FACS). In a proof-of-principle application, the system was used successfully to screen a mutant LbAdh library for variants showing improved activity with the substrate 4-methyl-2-pentanone.

Taking control over control: use of product sensing in single cells to remove flux control at key enzymes in biosynthesis pathways

Enzymes initiating the biosynthesis of cellular building blocks are frequently inhibited by the end-product of the respective pathway. Here we present an approach to rapidly generate sets of enzymes overriding this control. It is based on the in vivo detection of the desired end-product in single cells using a genetically encoded sensor. The sensor transmits intracellular product concentrations into a graded optical output, thus enabling ultrahigh-throughput screens by FACS. We randomly mutagenized plasmid-encoded ArgB of Corynebacterium glutamicum and screened the library in a strain carrying the sensor pSenLys-Spc, which detects l-lysine, l-arginine and l-histidine. Six of the resulting N-acetyl-l-glutamate kinase proteins were further developed and characterized and found to be at least 20-fold less sensitive toward l-arginine inhibition than the wild-type enzyme. Overexpression of the mutein ArgB-K47H-V65A in C. glutamicumΔargR led to the accumulation of 34 mM l-arginine in the culture medium. We also screened mutant libraries of lysC-encoded aspartate kinase and hisG-encoded ATP phosphoribosyltransferase. We isolated 11 LysC muteins, enabling up to 45 mM l-lysine accumulation, and 13 HisG muteins, enabling up to 17 mM l-histidine accumulation. These results demonstrate that in vivo screening of enzyme libraries by using metabolite sensors is extremely well suited to identify high-performance muteins required for overproduction.

Ab Initio calculations of even oxygen isotopes with chiral two-plus-three-nucleon interactions

We formulate the in-medium similarity renormalization group (IM-SRG) for open-shell nuclei using a multireference formalism based on a generalized Wick theorem introduced in quantum chemistry. The resulting multireference IM-SRG (MR-IM-SRG) is used to perform the first ab initio study of all even oxygen isotopes with chiral nucleon-nucleon and three-nucleon interactions, from the proton to the neutron drip lines. We obtain an excellent reproduction of experimental ground-state energies with quantified uncertainties, which is validated by results from the importance-truncated no-core shell model and the coupled cluster method. The agreement between conceptually different many-body approaches and experiment highlights the predictive power of current chiral two- and three-nucleon interactions, and establishes the MR-IM-SRG as a promising new tool for ab initio calculations of medium-mass nuclei far from shell closures.

Recombineering in Corynebacterium glutamicum combined with optical nanosensors: a general strategy for fast producer strain generation

Recombineering in bacteria is a powerful technique for genome reconstruction, but until now, it was not generally applicable for development of small-molecule producers because of the inconspicuous phenotype of most compounds of biotechnological relevance. Here, we establish recombineering for Corynebacterium glutamicum using RecT of prophage Rac and combine this with our recently developed nanosensor technology, which enables the detection and isolation of productive mutants at the single-cell level via fluorescence-activated cell sorting (FACS). We call this new technology RecFACS, which we use for genomic site-directed saturation mutagenesis without relying on pre-constructed libraries to directly isolate L-lysine-producing cells. A mixture of 19 different oligonucleotides was used targeting codon 81 in murE of the wild-type, at a locus where one single mutation is known to cause L-lysine production. Using RecFACS, productive mutants were screened and isolated. Sequencing revealed 12 different amino acid exchanges in the targeted murE codon, which caused different L-lysine production titers. Apart from introducing a rapid genome construction technology for C. glutamicum, the present work demonstrates that RecFACS is suitable to simply create producers as well as genetic diversity in one single step, thus establishing a new general concept in synthetic biology.

A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level

We present a novel method for visualizing intracellular metabolite concentrations within single cells of Escherichia coli and Corynebacterium glutamicum that expedites the screening process of producers. It is based on transcription factors and we used it to isolate new L-lysine producing mutants of C. glutamicum from a large library of mutagenized cells using fluorescence-activated cell sorting (FACS). This high-throughput method fills the gap between existing high-throughput methods for mutant generation and genome analysis. The technology has diverse applications in the analysis of producer populations and screening of mutant libraries that carry mutations in plasmids or genomes.

Behavioral alterations and changes in Ca/calmodulin kinase II levels in the striatum of connexin36 deficient mice

Gap junctions (GJ) are intercellular channels which directly connect the cytoplasm of adjacent cells. GJ allow direct cell-to-cell communication via the diffusion of ions, metabolites and second messengers such as IP(3). The connexin36 (Cx36) protein has been detected in GJ between interneurons of the hippocampus, cerebral cortex, striatum, amygdala, the inferior olive, cerebellum and other brain structures, such as the olfactory bulb. Cx36 knockout (Cx36 KO) mice display changes in synchronous network oscillations in the hippocampus, neocortex and inferior olive and exhibit impaired spatial alternation and one-trial object recognition in a Y-maze. Here, we further characterized the behavioral changes induced by Cx36 deficiency in the mouse by using different behavioral measures and experimental procedures. Additionally, we examined the effects of Cx36 deficiency on acetylcholine esterase (AChE) activity and calcium calmodulin kinase II alpha (CaMKII) protein levels in the striatum. The homozygous Cx36 KO mice displayed increased locomotion and running speed in the open-field, reduced object exploration and impaired one-trial object-place recognition. Furthermore, they exhibited more anxiety-like behavior as compared to the heterozygous controls in the light-dark box. Homozygous Cx36 KO mice exhibited reduced CaMKII levels in the striatum as compared to the heterozygous mice. AChE activity in the striatum was not significantly different between groups. The present results suggest that Cx36 deficiency in the mouse leads to reduced CaMKII levels in the striatum and behavioral changes in open-field activity, anxiety-related behavior in the light-dark box and one-trial object-place recognition.

In vitro cytotoxicity and phototoxicity study of cosmetics colorants

The aim of the work was early identification of preventable risk factors connected with the consumers usage of products of everyday use, such as cosmetics, toys and children products, and other materials intended for contact with human skin. The risk factor is represented by substances with irritation potential and subsequent possible sensitisation, resulting in negative impact on human physical and psychical health with social and societal consequences. The legislation for cosmetics, chemical substances and other products requires for hazard identification the application of alternative toxicological methods in vitro without the use of animals. For this reason we used a battery of alternative assays in vitro, based on cell cultures. Progressive methods of molecular biology, based on fluorimetry and fluorescence, were employed for identification of early morphological and functional changes on cellular level. Four colorants frequently used in cosmetics (P-WS Caramel, Chlorophyllin, Unicert Red K 7054-J and Unicert Red K 7008-J) were tested on cell line NIH3T3 (mouse fibroblast cell) and 3T3 Balb/c with/without UV irradiation (dose 5 J cm(-2)). Fluorescence methods for the study of cell damage using fluorescence probes offer results for the evaluation of cytotoxicity and cell viability of adherent cells. We detected intracellular production of ROS investigated by molecular probe CM-H(2)DCFDA, which is primarily sensitive to the increased production of hydrogen peroxide or its downstream products. Toxic effects on the cellular level were identified by viability tests using Neutral Red uptake and MTT assay, where the live cells reduce yellow soluble 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to insoluble formazan crystals. The reaction was investigated on mitochondrial membrane of living cells and the type of cell death was determined using Apoptosis detection kit. Cytotoxicity tests revealed health risks of using Chlorophyllin and Unicert Red K 7054-J.

Phototoxic effect of TPPS4 and MgTPPS4 on DNA fragmentation of HeLa cells

Photodynamic therapy (PDT) is an alternative method of tumour treatment. It is based on a photochemical reaction of a photosensitizer, irradiation, and O(2) which converts to cytotoxic (1)O(2) and other forms of reactive oxygen species (ROS). The comet assay (also called single-cell gel electrophoresis, SCGE) is a sensitive, simple and quantitative technique for detection of DNA damage. In our study we investigated the phototoxicity of the two porphyrin photosensitizers, TPPS4 and MgTPPS4, on HeLa cells. Three different radiation doses and six different concentrations of the photosensitizers were used. Our results show that the DNA of the cells treated with the TPPS(4) and MgTPPS(4) at the concentrations higher than 5 μM was highly fragmented indicating a strong phototoxic effect resulting in a cell apoptosis. On the base of our results we can hypothesize that even the irradiation dose of 1 J cm(-2) is sufficient enough to provoke the DNA fragmentation.

Complement factor H gene polymorphisms and Chlamydia pneumoniae infection in age-related macular degeneration

PURPOSE

To investigate the association of the complement factor H gene (CFH)Y402H polymorphism and age-related macular degeneration (AMD) in the Austrian population (Caucasoid descent), and to determine whether there is an association between exposure to Chlamydia pneumoniae-responsible for up to 20% of community-acquired pneumoniae-and the AMD-associated CFHrisk polymorphism.

METHODS

Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis in 75 unrelated AMD patients and compared with 75 healthy, age-matched control subjects. C. pneumoniaeserum IgG was tested by ELISA (R&D) in both groups. The association between the CFHY402H genetic polymorphism and the disease was examined by chi (2)-test and logistic regression.

RESULTS

CFH Y402H genotypefrequencies differed significantly between AMD patients and healthy controls (1277 TT, 22.7%; 1277 TC, 53.3%; and 1277 CC, 22.7% in the AMD group; 1277 TT, 48.0%; 1277 TC, 38.7%; and 1277 CC, 13.3% in the control group) showing a P-value <0.005 (OR:2.920/3.811).No association was found between a positive C. pneumoniae titre and AMD (P=0.192), nor was any association found between C. pneumoniae and the CFH Y402H polymorphism.

CONCLUSIONS

Our data confirm that the CFHY402H polymorphism is a risk factor for AMD in the Austrian population with a higher frequency of the Y402 polymorphism in AMD patients. No association between preceding C. pneumoniaeinfection and diagnosed AMD was found.

Modeling the effect of facial topographies upon the visual field of humans and primates

PURPOSE

To establish a virtual device that can predict the effect of facial features on the visual field of humans and primates.

METHODS

Virtual masks were obtained from human subjects, and macaque, chimpanzee and baboon taxidermic specimens, and aligned with upright head orientation at the center of a virtual perimeter-like dome (radius = 50 m) developed with Cinema 4D. Virtual searchlights positioned at the masks' pupils were then allowed to 'paint' facial elements obstructing their path, and demarcate the unobstructed rays at the perimetric surface and on a virtual ground floor related to eye level. Searchlight positions along the human mask's pupillary axis were identified by maximum congruence to Goldmann visual field limits.

RESULTS

The human contours largely concur with large-stimulus isopters displaying the limiting role of the nasal ridge, and the relatively extended ventral and temporal limits. In contrast, the facial design of chimpanzees and baboons obstructs significant portions of the ventral foreground (>2 m cf < 0.5 m in human), while there appear to be larger binocular overlaps (125 degrees in chimp cf 90 degrees in human).

CONCLUSIONS

The model provides information on anatomical constraints for monocular and binocular visual field extensions including projection of the ventral field on a virtual floor.

UV-light-induced conversion and aggregation of prion proteins

Increasing evidence suggests a central role for oxidative stress in the pathology of prion diseases, a group of fatal neurodegenerative disorders associated with structural conversion of the prion protein (PrP). Because UV-light-induced protein damage is mediated by direct photo-oxidation and radical reactions, we investigated the structural consequences of UVB radiation on recombinant murine and human prion proteins at pH 7.4 and pH 5.0. As revealed by circular dichroism and dynamic light scattering measurements, the observed PrP aggregation follows two independent pathways: (i) complete unfolding of the protein structure associated with rapid precipitation or (ii) specific structural conversion into distinct soluble beta-oligomers. The choice of pathway was directly attributed to the chromophoric properties of the PrP species and the susceptibility to oxidation. Regarding size, the oligomers characterized in this study share a high degree of identity with oligomeric species formed after structural destabilization induced by other triggers, which significantly strengthens the theory that partly unfolded intermediates represent initial precursor molecules directing the pathway of PrP aggregation. Moreover, we identified the first suitable photo-trigger capable of inducing refolding of PrP, which has an important biotechnological impact in terms of analyzing the conversion process on small time scales.