Proline-coated gold nanoparticles as a highly efficient nanocatalyst for the enantioselective direct aldol reaction in water

Reported is an efficient approach to the synthesis of water-soluble proline-coated gold nanoparticles through a place exchange reaction between pentanethiolate stabilized gold nanoparticles and a proline-tethered amphiphilic thiol. Preliminary studies show that the nanocatalyst is highly active in an enamine type aldolisation leading to the desired product with nearly perfect diastereoselectivity and enantioselectivity using water as an innocuous solventMinisterio de Economía y Competitividad CTQ2010-21755-CO2-00Junta de Andalucía P07-FQM-277

NMR study on the stabilization and chiral discrimination of sulforaphane enantiomers and analogues by cyclodextrins

Sulforaphane (SFN), a phytochemical isolated from broccoli, is an important antitumoral compound with additional beneficial effect on other important diseases. However, the chemical instability of SFN has hampered its clinical use. In order to circumvent this problem, we report the first comparative study on the inclusion complexes of SFN and SFN homologues with different cyclodextrins by NMR spectroscopy. From this study it has been shown that α-CD is the most indicated cyclodextrin for the stabilization of SFN and SFN homologues, and that the highest affinity constant is that of the isothiocyanate obtained from the wasabi. Furthermore, the study of the inclusion complexes of α-CD and the non-natural SFN and analogues with S absolute configuration at sulfur shows for the first time that α-CD is able to discriminate between the two enantiomers, with the natural R enantiomers forming the inclusion complexes with higher affinity.Ministerio de Economía yCompetitividad (grants No. CTQ2016-78580-C2-1-R, and CTQ2016-78580-C2-2-R)Junta de Andalucía (P11-FQM-8046)EvgenPharm

Stereoselective synthesis of hydroxylated 3-aminoazepanes using a multi-bond forming, three-step tandem process

A multi-bond forming, three-step tandem process involving a palladium(II)-catalysed Overman rearrangement and a ring closing metathesis reaction has been utilised for the efficient synthesis of a 2,3,6,7-tetrahydro-3-amidoazepine. Substrate directed epoxidation or dihydroxylation of this synthetic intermediate has allowed the diastereoselective synthesis of hydroxylated 3-aminoazepanes including the syn-diastereomer of the balanol core. Asymmetric synthesis of the 2,3,6,7-tetrahydro-3-amidoazepine motif was also achieved using a chiral palladium(II)-catalyst during the Overman rearrangement

Distribution pattern of antibiotic resistance genes in Escherichia coli isolated from colibacillosis cases in broiler farms of Egypt

Background and Aim: Multidrug resistance (MDR) of Escherichia coli has become an increasing concern in poultry farming worldwide. However, E. coli can accumulate resistance genes through gene transfer. The most problematic resistance mechanism in E. coli is the acquisition of genes encoding broad-spectrum β-lactamases, known as extended-spectrum β-lactamases, that confer resistance to broad-spectrum cephalosporins. Plasmid-mediated quinolone resistance genes (conferring resistance to quinolones) and mcr-1 genes (conferring resistance to colistin) also contribute to antimicrobial resistance. This study aimed to investigate the prevalence of antimicrobial susceptibility and to detect β-lactamase and colistin resistance genes of E. coli isolated from broiler farms in Egypt. Materials and Methods: Samples from 938 broiler farms were bacteriologically examined for E. coli isolation. The antimicrobial resistance profile was evaluated using disk diffusion, and several resistance genes were investigated through polymerase chain reaction amplification. Results: Escherichia coli was isolated and identified from 675/938 farms (72%) from the pooled internal organs (liver, heart, lung, spleen, and yolk) of broilers. Escherichia coli isolates from the most recent 3 years (2018–2020) were serotyped into 13 serotypes; the most prevalent serotype was O125 (n = 8). The highest phenotypic antibiotic resistance profiles during this period were against ampicillin, penicillin, tetracycline, and nalidixic acid. Escherichia coli was sensitive to clinically relevant antibiotics. Twenty-eight selected isolates from the most recent 3 years (2018–2020) were found to have MDR, where the prevalence of the antibiotic resistance genes ctx, tem, and shv was 46% and that of mcr-1 was 64%. Integrons were found in 93% of the isolates. Conclusion: The study showed a high prevalence of E. coli infection in broiler farms associated with MDR, which has a high public health significance because of its zoonotic relevance. These results strengthen the application of continuous surveillance programs

Design and synthesis of conformationally restricted carbocyclic nucleosides

Los nucleósidos carbocíclicos son análogos de nucleósidos en los que el átomo de oxígeno del anillo furanósico está reemplazado por un grupo metileno. La ausencia de una verdadera unión glicosídica le otorga mayor estabilidad metabólica pues no son afectados por fosforilasas e hidrolasas que sí atacan a los nucleósidos convencionales. Las enzimas responsables de distintas acciones farmacológicas de los nucleósidos convencionales también reconocen los análogos carbocíclicos correspondientes, obteniéndose un amplio rango de propiedades biológicas, especialmente como agentes antivirales y antitumorales. La conformación en este tipo de drogas cumple un rol fundamental en la actividad biológica; sin embargo, los carbanucleósidos presentan una conformación distinta a la de los nucleósidos convencionales en solución, por lo que son menos efectivos. N-metano-carba-timidina (50), un carbanucleósido sintético rígido en la conformación Norte y estructuralmente relacionado al nucleósido carbocíclico natural neplanocina C (48), construido en un sistema bicíclico[3.1.0]hexano, exhibió una potentísima acción antiherpética, incluso mayor que aciclovir. Por este motivo, se llevaron a cabo estudios sintéticos para optimizar su estructura química. En los dos primeros capítulos de esta tesis se describen los antecedentes de nucleósidos, sus análogos carbocíclicos y aquellos que presentan restricciones conformacionales. También se incluye un resumen de los métodos de síntesis más comunes para la preparación de carbanucleósidos y la síntesis y actividad biológica de los compuestos más relevantes de esta familia de análogos. En el tercer capítulo se extendió el estudio de la monoprotección regioselectiva de glicoles por tratamiento con DIBAL-H y ortoformiato de metilo catalizado por nitrato cérico amónico. Este estudio surgió de la necesidad de proteger regioselectivamente un hidroxilo alílico secundario frente a uno homoalílico, durante la síntesis enantioselectiva de (+)-neplanocina F (183), realizada en nuestro laboratorio. En los capítulos cuatro y cinco se presenta la primera síntesis de nucleósidos carbocíclicos conformacionalmente restringidos en una conformación de tipo Norte, construidos en un sistema tiabiciclo[3.1.0]hexano. Para dicho estudio se desarrollaron nuevos métodos para la preparación de episulfuros fusionados a anillos de cinco miembros sintetizándose primero modelos simples de carbanucleósidos construidos sobre este sistema azufrado. N-tia-carba-timidina (273) se comportó como un agente antiherpético muy potente, comparable a aciclovir

استخدام جسيمات أكسيد الزنك النانوميترية في تثبيط التلف الحيوي لألحجار الجيرية ال ثرية The Use of zinc oxide nanoparticles for the inhibition the biodeterioration of Archaeological lime stones

{AR} يناقش البحث دراسة لاستخدام جسيمات أكسيد الزنك النانوميترية في تثبيط التلف الحيوي للأحجار الجيرية الأثرية في معبد حيرشاف بأهناسيا، حيث تم عزل مسحات من الأسطح الأثرية خلال فصول السنة الأربعة وتم تعريفها مرفولوجيا إلى (Aspergillus niger , Aspergillus flavus , Rhizopus stolonifer , Alternaria alternata , Aspergillus nidulans and Rhizopus oryzae)، بالإضافة إلى بكتيريا من جنس (Bacillus cereus and Bacillus subtilis ، Bacillus anthracis )، تم تحضير جسيمات أكسيد الزنك معمليا وفحص الجسيمات باستخدام الميكروسكوب الإلكتروني النافذ للتأكد من حجم الحبيبات وأنها في الحجم النانوي والتي أظهرت أن حبيبات الزنك تتخذ الشكل الكروي مع متوسط قطر من (22.32 nm : 54.85 nm ). كما تم في هذا البحث دراسة تأثير النشاط الضد ميكروبي للأجناس الفطرية والبكتيرية المعزولة من الأسطح الأثرية وأظهرت الدراسة قدرة جسيمات أكسيد الزنك بتركيزين( 615.38ppm) و (769.23ppm)، على تثبيط نمو الكائنات الحية الدقيقة المعزولة، وتم أخذ مسحات من الأثر بعد تطبيق جسيمات أكسيد الزنك النانوي وزرعها من جديد في أطباق البتري وأكدت النتائج عدم قدرة أي من الكائنات الحية الدقيقة المعزولة على النمو من جديد, و تعد هذه الطريقة من الطرق الحديثة في المقاومة الحيوية وهي طريقة آمنة حتى الآن ولا تتفاعل كيميائيا مع الأثر. {EN} The aim of this research is studying the effect of using Zinc Oxide nanoparticles to inhibit the bio-deterioration of the archaeological limestones and applied the nanoparticles on the Temple of Hershaf, Ehanasia, Egypt. Swabs were isolated from the archaeological surfaces during the four seasons and morphologically identified to (Aspergillus niger, Aspergillus flavus, Rhizopus stoloniferna, Alternaria alterans and Rhizopus oryzae), in addition of (Bacillus cereus and Bacillus subtilis, Bacillus anthracis) as genus of bacteria. Zinc oxide particles were prepared in the laboratory and the particles were examined by Transmission Electron Microscope (TEM) to confirm the size of the particles which showed that the Zinc Oxide grains take hexagonal and spherical shapes with an average diameter of (22.32: 54.85 nm). Hence, the antimicrobial activity of fungal and bacterial species isolated from archaeological surfaces was studied. The study showed the ability of Zinc Oxide particles (with concentrations 615.38 (ppm) and (769.23ppm) to inhibit the growth rate of the isolated microorganisms. After two months from applying Zinc oxide nanoparticles on the replica, swabs were taken and implanted again in Petri dishes, and the results confirmed that none of the isolated microorganisms was able to grow again. This method is considered as one of the modern methods of biological treatments, and it is a safe method for the conservators and the visitors and does not chemically interact with archaeological stones

Molecular Characterization and Phylogenetic Analysis of Fowl Adenoviruses Isolated from Broiler Chicken Flocks

FADV has caused high economic losses in poultry industry in Egypt in the last few years. The study aimed to detect and genetically characterize the fowl adenovirus (FAdV) species prevalent in Egyptian commercial broiler chicken flocks during 2023. The 63 suspected samples were collected from Egyptian broiler chickens from 5 governorates during 2023. The molecular characterization was performed by using polymerase chain reaction (PCR) and the positive samples was isolated in primary chicken embryo liver (CEL) cells. The genetic characterization of 8 selected samples represented different governorates by sequencing of loop 1 (L1) of the hexon gene. Clinically, the poultry suffered from depression, watery diarrhea, and ascites and decreased body weight with a mortality rate of 10–30%. The post-mortem inspection showed liver was pale, enlarged with petechial haemorrhage. 27 out of 63 samples (42.8%) were positive by PCR. The molecular charctersation of the L1 hexon gene’s revealed that the FADV (from Eg-ANY1-2023 to EG-ANY4-2023) genetically charcterized as FADV-D 2/11 strains, the FADV-EG-ANY5-2023 to FADV-EG-ANY8-2023 genetically characterized as FADV E/8a and FADV E/8b. By mutation analysis, the strains in our study related to FADV-E/8a (FADV-EG-ANY5, ANY6) had R171K in the HVR4 and strain related to 8b (FADV-EG-ANY7, ANY8) had S95N in the HVR2 and A91T between HVR1 and HVR2 compared to other reference strains. Thus, these findings demonstrate that many mutated virus genotypes are circulating in commercial chicken flocks. Further research is needed to study the pathogencity of these strains and implement control measures and vaccine production to prevent economic loss in the poultry industry