476 research outputs found
N′-(2-Methoxybenzylidene)nicotinohydrazide
The title compound, C14H13N3O2, was prepared by the reaction of 2-methoxybenzyaldehyde with nicotinic acid hydrazide in methanol. The dihedral angle between the benzene and pyridine rings is 5.9 (3)°. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds, leading to the formation of chains along the c axis; adjacent chains are linked via C—H⋯O and C—H⋯N hydrogen bonds
Antibiotic Resistomes in Plant Microbiomes
Microorganisms associated with plants may alter the traits of the human microbiome important for human health, but this alteration has largely been overlooked. The plant microbiome is an interface between plants and the environment, and provides many ecosystem functions such as improving nutrient uptake and protecting against biotic and abiotic stress. The plant microbiome also represents a major pathway by which humans are exposed to microbes and genes consumed with food, such as pathogenic bacteria, antibiotic-resistant bacteria, and antibiotic-resistance genes. In this review we highlight the main findings on the composition and function of the plant microbiome, and underline the potential of plant microbiomes in the dissemination of antibiotic resistance via food consumption or direct contact
Population Genetic Structure and Phylogeography of Camellia flavida (Theaceae) Based on Chloroplast and Nuclear DNA Sequences
Camellia flavida is an endangered species of yellow camellia growing in limestone mountains in southwest China. The current classification of C. flavida into two varieties, var. flavida and var. patens, is controversial. We conducted a genetic analysis of C. flavida to determine its taxonomic structure. A total of 188 individual plants from 20 populations across the entire distribution range in southwest China were analyzed using two DNA fragments: a chloroplast DNA fragment from the small single copy region and a single-copy nuclear gene called phenylalanine ammonia-lyase (PAL). Sequences from both chloroplast and nuclear DNA were highly diverse; with high levels of genetic differentiation and restricted gene flow. This result can be attributed to the high habitat heterogeneity in limestone karst, which isolates C. flavida populations from each other. Our nuclear DNA results demonstrate that there are three differentiated groups within C. flavida: var. flavida 1, var. flavida 2, and var. patens. These genetic groupings are consistent with the morphological characteristics of the plants. We suggest that the samples included in this study constitute three taxa and the var. flavida 2 group is the genuine C. flavida. The three groups should be recognized as three management units for conservation concerns
N′-(2-Methoxy-1-naphthylidene)nicotinohydrazide
The title compound, C18H15N3O2, was prepared by the reaction of 2-methoxynaphthaldehyde with nicotinic acid hydrazide in methanol. The dihedral angle between the naphthalene ring system and the pyridine ring is 9.2 (3)°. An intramolecular C—H⋯N hydrogen bond is observed. In the crystal structure, molecules are linked into chains running along the c axis by intermolecular N—H⋯O hydrogen bonds
(E)-N′-(3,5-Dibromo-2-hydroxybenzylidene)nicotinohydrazide
In the title Schiff base compound, C13H9Br2N3O2, there is an intramolecular O-H⋯N hydrogen bond involving the hydroxyl substituent and the adjacent hydrazine N atom. The molecule is almost planar, the dihedral angle between the benzene ring and the pyridine ring being 5.7 (2)°. In the crystal structure, symmetry-related molecules are linked via N—H⋯O hydrogen bonds, forming chains propagating in [001]
Backreaction in Axion Monodromy, 4-forms and the Swampland
Axion monodromy models can always be described in terms of an axion coupled
to 3-form gauge fields with non-canonical kinetic terms. The presence of the
saxions parametrising the kinetic metrics of the 3-form fields leads to
backreaction effects in the inflationary dynamics. We review the case in which
saxions backreact on the K\"ahler metric of the inflaton leading to a
logarithmic scaling of the proper field distance at large field. This behaviour
is universal in Type II string flux compactifications and consistent with a
refinement of the Swampland Conjecture. The critical point at which this
behaviour appears depends on the mass hierarchy between the inflaton and the
saxions. However, in tractable compactifications, such a hierarchy cannot be
realised without leaving the regime of validity of the effective theory,
disfavouring transplanckian excursions in string theory.Comment: Proceedings prepared for the "Workshop on Geometry and Physics",
November 2016, Ringberg Castl
4-(1,3-Benzothiazol-2-yl)-N-(2-pyridylmethyl)aniline monohydrate
In the title compound, C19H15N3S·H2O, the benzothiazole ring system forms a dihedral angle of 7.22 (1)° with the benzene ring and the benzene ring forms a dihedral angle of 80.89 (1)° with the pyridine ring. An intramolecular N—H⋯O interaction is present. The crystal structure is stablized by intermolecular O—H⋯N hydrogen bonds, π–π [centroid–centroid distances = 3.782 (1), 3.946 (1) and 3.913 (1) Å] and C—H⋯π interactions, forming a three dimensional-network
Risk factors of amyotrophic lateral sclerosis: a global meta-summary
BackgroundThe etiology of amyotrophic lateral sclerosis (ALS) remains largely unknown. This study aimed to summarize the relationship between ALS and its genetic and non-genetic risk factors.MethodA search of relevant literature from PubMed, Embase, and Cochrane Database from inception to December 2022 was performed. Random-effects or fixed-effects models were performed by Stata MP 15.0 to pool multivariate or adjusted ratios (OR). PROSPERO registration number: CRD42022301549.Results230 eligible studies were included, of which 67 involved 22 non-genetic factors, and 163 involved genetic factors. Four aspects of non-genetic factors, including lifestyle, environmental and occupational exposures, pre-existing diseases/comorbidity and medical exposures, and others, were analyzed. Exposure to heavy metals (OR = 1.79), pesticides (OR = 1.46), solvents (OR = 1.37), previous head trauma (OR = 1.37), military service (OR = 1.29), stroke (OR = 1.26), magnetic field (OR = 1.22) and hypertension (OR = 1.04) are significant risk factors, but use of antidiabetics (OR = 0.52), high BMI (OR = 0.60 for obese and overweight vs. normal and underweight), living in urban (OR = 0.70), diabetes mellitus (OR = 0.83), and kidney disease (OR = 0.84) decrease the risk for ALS. In addition, eight common ALS-related genes were evaluated, the mutation frequencies of these genes were ranked from highest to lowest as SOD1 (2.2%), C9orf72 (2.1%), ATXN2 (1.7%), FUS (1.7%), TARDBP (0.8%), VCP (0.6%), UBQLN2(0.6%) and SQSTM1 (0.6%) in all the ALS patients.ConclusionsOur findings suggested that effective intervention for risk exposure and timely modification of lifestyle might prevent the occurrence of ALS. Genetic mutations are important risk factors for ALS and it is essential to detect genetic mutations correctly and scientifically.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=301549, identifier: CRD42022301549
Loss of soil microbial diversity exacerbates spread of antibiotic resistance
Loss of biodiversity is a major threat to the ecosystem processes upon which society depends. Natural ecosystems differ in their resistance to invasion by alien species, and this resistance can depend on the diversity in the system. Little is known, however, about the barriers that microbial diversity provides against microbial invasion. The increasing prevalence of antibiotic-resistant bacteria is a serious threat to public health in the 21st century. We explored the consequences of the reduction in soil microbial diversity for the dissemination of antibiotic resistance. The relationship between this diversity and the invasion of antibiotic resistance was investigated using a dilution-to-extinction approach coupled with high-capacity quantitative PCR. Microbial diversity was negatively correlated with the abundance of antibiotic-resistance genes, and this correlation was maintained after accounting for other potential drivers such as incubation time and microbial abundance. Our results demonstrate that high microbial diversity can act as a biological barrier resist the spread of antibiotic resistance. These results fill a critical gap in our understanding of the role of soil microbial diversity in the health of ecosystem
- …