The [4+2]‐Cycloaddition of α‐Nitrosoalkenes with Thiochalcones as a Prototype of Periselective Hetero‐Diels–Alder Reactions—Experimental and Computational Studies

The [4+2]‐cycloadditions of α‐nitrosoalkenes with thiochalcones occur with high selectivity at the thioketone moiety of the dienophile providing styryl‐substituted 4H‐1,5,2‐oxathiazines in moderate to good yields. Of the eight conceivable hetero‐Diels–Alder adducts only this isomer was observed, thus a prototype of a highly periselective and regioselective cycloaddition has been identified. Analysis of crude product mixtures revealed that the α‐nitrosoalkene also adds competitively to the thioketone moiety of the thiochalcone dimer affording bis‐heterocyclic [4+2]‐cycloadducts. The experiments are supported by high‐level DFT calculations that were also extended to related hetero‐Diels–Alder reactions of other nitroso compounds and thioketones. These calculations reveal that the title cycloadditions are kinetically controlled processes confirming the role of thioketones as superdienophiles. The computational study was also applied to the experimentally studied thiochalcone dimerization, and showed that the 1,2‐dithiin and 2H‐thiopyran isomers are in equilibrium with the monomer. Again, the DFT calculations indicate kinetic control of this process

First isolation and further characterization of enteropathogenic Escherichia coli (EPEC) O157:H45 strains from cattle

BACKGROUND: Enteropathogenic Escherichia coli (EPEC), mainly causing infantile diarrhoea, represents one of at least six different categories of diarrheagenic E. coli with corresponding distinct pathogenic schemes. The mechanism of EPEC pathogenesis is based on the ability to introduce the attaching-and-effacing (A/E) lesions and intimate adherence of bacteria to the intestinal epithelium. The role and the epidemiology of non-traditional enteropathogenic E. coli serogroup strains are not well established. E. coli O157:H45 EPEC strains, however, are described in association with enterocolitis and sporadic diarrhea in human. Moreover, a large outbreak associated with E. coli O157:H45 EPEC was reported in Japan in 1998. During a previous study on the prevalence of E. coli O157 in healthy cattle in Switzerland, E. coli O157:H45 strains originating from 6 fattening cattle and 5 cows were isolated. In this study, phenotypic and genotypic characteristics of these strains are described. Various virulence factors (stx, eae, ehxA, astA, EAF plasmid, bfp) of different categories of pathogenic E. coli were screened by different PCR systems. Moreover, the capability of the strains to adhere to cells was tested on tissue culture cells. RESULTS: All 11 sorbitol-positive E. coli O157:H45 strains tested negative for the Shiga toxin genes (stx), but were positive for eae and were therefore considered as EPEC. All strains harbored eae subtype α1. The gene encoding the heat-stable enterotoxin 1 (EAST1) was found in 10 of the 11 strains. None of the strains, however, carried ehx A genes. The capability of the strains to adhere to cells was shown by 10 strains harbouring bfp gene by localized adherence pattern on HEp-2 and Caco-2 cells. CONCLUSION: This study reports the first isolation of typical O157:H45 EPEC strains from cattle. Furthermore, our findings emphasize the fact that E. coli with the O157 antigen are not always STEC but may belong to other pathotypes. Cattle seem also to be a reservoir of O157:H45 EPEC strains, which are described in association with human diseases. Therefore, these strains appear to play a role as food borne pathogens and have to be considered and evaluated in view of food safety aspects

Serotypes, intimin variants and other virulence factors of eae positive Escherichia coli strains isolated from healthy cattle in Switzerland. Identification of a new intimin variant gene (eae-η2)

BACKGROUND: Enteropathogenic Escherichia coli (EPEC) and Shigatoxin-producing Escherichia coli (STEC) share the ability to introduce attaching-and-effacing (A/E) lesions on intestinal cells. The genetic determinants for the production of A/E lesions are located on the locus of enterocyte effacement (LEE), a pathogenicity island that also contains the genes encoding intimin (eae). This study reports information on the occurrence of eae positive E. coli carried by healthy cattle at the point of slaughter, and on serotypes, intimin variants, and further virulence factors of isolated EPEC and STEC strains. RESULTS: Of 51 eae positive bovine E. coli strains, 59% were classified as EPEC and 41% as STEC. EPEC strains belonged to 18 O:H serotypes, six strains to typical EPEC serogroups. EPEC strains harbored a variety of intimin variants with eae-β1 being most frequently found. Moreover, nine EPEC strains harbored astA (EAST1), seven bfpA (bundlin), and only one strain was positive for the EAF plasmid. We have identified a new intimin gene (η2) in three bovine bfpA and astA-positive EPEC strains of serotype ONT:H45. STEC strains belonged to seven O:H serotypes with one serotype (O103:H2) accounting for 48% of the strains. The majority of bovine STEC strains (90%) belonged to five serotypes previously reported in association with hemolytic uremic syndrom (HUS), including one O157:H7 STEC strain. STEC strains harbored four intimin variants with eae-ε1 and eae-γ1 being most frequently found. Moreover, the majority of STEC strains carried only stx1 genes (13 strains), and was positive for ehxA (18 strains) encoding for Enterohemolysin. Four STEC strains showed a virulence pattern characteristic of highly virulent human strains (stx2 and eae positive). CONCLUSION: Our data confirm that ruminants are an important source of serologically and genetically diverse intimin-harboring E. coli strains. Moreover, cattle have not only to be considered as important asymptomatic carriers of O157 STEC but can also be a reservoir of EPEC and eae positive non-O157 STEC, which are described in association with human diseases

A Neurotrophin Signaling Cascade Coordinates Sympathetic Neuron Development through Differential Control of TrkA Trafficking and Retrograde Signaling

AbstractA fundamental question in developmental biology is how a limited number of growth factors and their cognate receptors coordinate the formation of tissues and organs endowed with enormous morphological complexity. We report that the related neurotrophins NGF and NT-3, acting through a common receptor, TrkA, are required for sequential stages of sympathetic axon growth and, thus, innervation of target fields. Yet, while NGF supports TrkA internalization and retrograde signaling from distal axons to cell bodies to promote neuronal survival, NT-3 cannot. Interestingly, final target-derived NGF promotes expression of the p75 neurotrophin receptor, in turn causing a reduction in the sensitivity of axons to intermediate target-derived NT-3. We propose that a hierarchical neurotrophin signaling cascade coordinates sequential stages of sympathetic axon growth, innervation of targets, and survival in a manner dependent on the differential control of TrkA internalization, trafficking, and retrograde axonal signaling

Organelle-specific targeting of polymersomes into the cell nucleus

Synthetic nanomaterials are being sought to shuttle therapeutic payloads directly into the cell nucleus as a major target for chemo- and gene-based therapies. However, it remains uncertain whether and how synthetic entities are able to bypass the nuclear pore complexes (NPCs) that regulate transport into and out of the nucleus. We have constructed biocompatible polymer vesicles that infiltrate NPCs and resolved their nuclear uptake mechanism in vitro and in vivo. Their ability to deliver payloads directly into cell nuclei is further validated by transmission electron microscopy.Organelle-specific nanocarriers (NCs) are highly sought after for delivering therapeutic agents into the cell nucleus. This necessitates nucleocytoplasmic transport (NCT) to bypass nuclear pore complexes (NPCs). However, little is known as to how comparably large NCs infiltrate this vital intracellular barrier to enter the nuclear interior. Here, we developed nuclear localization signal (NLS)-conjugated polymersome nanocarriers (NLS-NCs) and studied the NCT mechanism underlying their selective nuclear uptake. Detailed chemical, biophysical, and cellular analyses show that karyopherin receptors are required to authenticate, bind, and escort NLS-NCs through NPCs while Ran guanosine triphosphate (RanGTP) promotes their release from NPCs into the nuclear interior. Ultrastructural analysis by regressive staining transmission electron microscopy further resolves the NLS-NCs on transit in NPCs and inside the nucleus. By elucidating their ability to utilize NCT, these findings demonstrate the efficacy of polymersomes to deliver encapsulated payloads directly into cell nuclei

Impact on visual acuity in neovascular age related macular degeneration (Namd) in europe due to covid-19 pandemic lockdown

This is a retrospective, multicenter study of consecutive patients with nAMD scheduled for a visit and/or a treatment with an intravitreal injection (IVI) during the 3 months before lockdown in the Ophthalmology Departments of six centers of Europe.The study was conducted on 546 patients, of which 55.13% were females, almost 100% of the patients were White/Caucasian race, and 71.53% of the patients presented a type 1 macular neovascularization (NVM). A total of 62.82% of patients (343 patients) that were on scheduled clinic visits and/or intravitreal injection treatment during the 3 months before the quarantine did not attend either to visit or for treatment during the lockdown. The mean number of injections during the lockdown was significantly reduced. This was followed by a significant reduction in the mean best-corrected visual acuity (BCVA) between the 3 months before the lockdown (mean BCVA of 60.68 ± 19.77 letters) and 6 months after lockdown (mean BCVA of 56.98 ± 22.59 letters). Patients with better BCVA before the lockdown and the ones showing neovascular activity were more likely to attend their scheduled visits and/or IVI treatments. The COVID-19 pandemic and the lockdown have led to a decrease in the number of IVI treatments in patients with nAMD, evidencing a significant vision loss at 6 months

Transdiagnostic prevention and intervention efforts are needed to address executive dysfunction

Abstract: Executive functioning (EF) is a multi-faceted construct important to activities of daily living, emotion regulation, and higher-order thinking and is often impaired in individuals with gambling disorder and/or alcohol use disorders. Deficits in EF are associated with poor treatment engagement, psychiatric comorbidities, and relapse. The present study examined EF in college students (N = 832) aged 18-24 (M= 19.23, SD=1.37, 76.5% Women) in relation to gambling and hazardous drinking. The Barkley’s Deficits in Executive Functioning was used to assess for global EF and 5 facets of EF: Time Management, Organization/Problem Solving, Self-Restraint, Self-Motivation, and Emotion-Regulation. Bivariate correlation and ANOVA analyses were conducted. Approximately 3% of college students reported problem gambling and 20% reported engagement in hazardous drinking. Compared to individuals with non-problem drinking and non-problem gambling: (1) individuals with problem gambling had worse global EF, self-restraint, emotion regulation, and self-motivation, (2) individuals with hazardous drinking had worse Global EF, self-restraint, and emotion regulation and (3) individuals with both problem gambling and hazardous drinking had worse EF on self-restraint. Implications: Impairments in several domains of EF (e.g., inhibition/self-restraint, emotion regulation, and self-motivation) were endorsed at a significantly higher rate among problematic gamblers and hazardous drinkers. Results partially support the pathways model of gambling (Blaszcynski & Nower, 2002) and support transdiagnostic prevention and intervention efforts around emotion regulation, motivation, and impulsivity

Impact on Visual Acuity in Neovascular Age Related Macular Degeneration (nAMD) in Europe Due to COVID-19 Pandemic Lockdown

This is a retrospective, multicenter study of consecutive patients with nAMD scheduled for a visit and/or a treatment with an intravitreal injection (IVI) during the 3 months before lockdown in the Ophthalmology Departments of six centers of Europe.The study was conducted on 546 patients, of which 55.13% were females, almost 100% of the patients were White/Caucasian race, and 71.53% of the patients presented a type 1 macular neovascularization (NVM). A total of 62.82% of patients (343 patients) that were on scheduled clinic visits and/or intravitreal injection treatment during the 3 months before the quarantine did not attend either to visit or for treatment during the lockdown. The mean number of injections during the lockdown was significantly reduced. This was followed by a significant reduction in the mean best-corrected visual acuity (BCVA) between the 3 months before the lockdown (mean BCVA of 60.68 +/- 19.77 letters) and 6 months after lockdown (mean BCVA of 56.98 +/- 22.59 letters). Patients with better BCVA before the lockdown and the ones showing neovascular activity were more likely to attend their scheduled visits and/or IVI treatments. The COVID-19 pandemic and the lockdown have led to a decrease in the number of IVI treatments in patients with nAMD, evidencing a significant vision loss at 6 months

Impact on Visual Acuity in Neovascular Age Related Macular Degeneration (nAMD) in Europe Due to COVID-19 Pandemic Lockdown

This is a retrospective, multicenter study of consecutive patients with nAMD scheduled for a visit and/or a treatment with an intravitreal injection (IVI) during the 3 months before lockdown in the Ophthalmology Departments of six centers of Europe.The study was conducted on 546 patients, of which 55.13% were females, almost 100% of the patients were White/Caucasian race, and 71.53% of the patients presented a type 1 macular neovascularization (NVM). A total of 62.82% of patients (343 patients) that were on scheduled clinic visits and/or intravitreal injection treatment during the 3 months before the quarantine did not attend either to visit or for treatment during the lockdown. The mean number of injections during the lockdown was significantly reduced. This was followed by a significant reduction in the mean best-corrected visual acuity (BCVA) between the 3 months before the lockdown (mean BCVA of 60.68 ± 19.77 letters) and 6 months after lockdown (mean BCVA of 56.98 ± 22.59 letters). Patients with better BCVA before the lockdown and the ones showing neovascular activity were more likely to attend their scheduled visits and/or IVI treatments. The COVID-19 pandemic and the lockdown have led to a decrease in the number of IVI treatments in patients with nAMD, evidencing a significant vision loss at 6 months

Ecological Guild Evolution and the Discovery of the World's Smallest Vertebrate

Living vertebrates vary drastically in body size, yet few taxa reach the extremely minute size of some frogs and teleost fish. Here we describe two new species of diminutive terrestrial frogs from the megadiverse hotspot island of New Guinea, one of which represents the smallest known vertebrate species, attaining an average body size of only 7.7 mm. Both new species are members of the recently described genus Paedophryne, the four species of which are all among the ten smallest known frog species, making Paedophryne the most diminutive genus of anurans. This discovery highlights intriguing ecological similarities among the numerous independent origins of diminutive anurans, suggesting that minute frogs are not mere oddities, but represent a previously unrecognized ecological guild