Genetic Origin Research Articles

Risk factors in the origin of Down syndrome

Down syndrome (DS) is the most common autosomal aneuploidy and the leading cause of intellectual disability of genetic origin worldwide. It is identified as a syndrome in which the variability of its clinical manifestations and the severity of its phenotype have a multifactorial origin. Worldwide prevalence ranges between 1 per 700 live births and several factors that may be involved in the origin of DS have been proposed. Our objective was to describe updates regarding risk factors in the cytogenetic origin or cause of DS. We conducted a narrative review study in which a literature search was carried out from January to June 2022 in databases such as PubMed, EBSCO, Medigraphic, ClinicalKey, and meta-search engines such as Elsevier and Evidence Alerts. Only articles published in the last 10 years in English and Spanish were included. The search terms used were: Down syndrome, risk factors, prevention. Although DS is a very common chromosomal pathology worldwide, there is no single risk factor at the origin of meiotic or mitotic nondisjunction of chromosome 21, but rather each of the associated risk factors contributes to a greater or lesser degree to a cytogenetic predisposition in the etiology of trisomy 21. During the review it was identified that the main established risk factor associated with DS is still advanced maternal age (≥ 35 years).

Obtaining dihaploid lines of soft winter wheat with complex resistance to rust and hard smut by anther culture in vitro

Aim. Obtaining homozygous linear material of winter soft wheat of different genetic origin (complex hybrids), which are resistant to different types of rust by androgenesis in vitro. Methods. In vitro culture of isolated anthers of wheat. The percentage of callus and regeneration of green plants for each genotype calculated as a percentage of the planted anthers. Methods of phytopathological assessment of resistance to complex of various diseases. Results. The differences in the frequency of сallus induction (from 0.99 to 16.26 % of planted anthers) and the ability to regenerate plants (from 0 to 3.05 % of planted anthers) in the process of androgenesiss in vitro of winter soft wheat were detected. Fertile regenerants in the anthers culture 5 out of 9 studied hybrids have been obtained. The effectiveness of the last process was different: from 12.5 to 60.0 % (an average of 29.41 %) from the received regenerants. The high degree (8–9 points) of the resistance of the obtained dihaploids to a complex of diseases was shown. Conclusions. Genotype-specific of microspores morphogenetic reactions of soft winter wheat in the process of androgenesis in vitro were revealed. The highest level of callus formation were shown for samples 120/20 and 132/20. 15 dihaploid lines with complex rust resistance and hard smut were obtained.

The multifaceted mitochondrial OXA insertase.

Most mitochondrial proteins are synthesized in the cytosol and transported into mitochondria by protein translocases. Yet, mitochondria contain their own genome and gene expression system, which generates proteins that are inserted in the inner membrane by the oxidase assembly (OXA) insertase. OXA contributes to targeting proteins from both genetic origins. Recent data provides insights into how OXA cooperates with the mitochondrial ribosome during synthesis of mitochondrial-encoded proteins. A picture of OXA emerges in which it coordinates insertion of OXPHOS core subunits and their assembly into protein complexes but also participates in the biogenesis of select imported proteins. These functions position the OXA as a multifunctional protein insertase that facilitates protein transport, assembly, and stability at the inner membrane.

Detection of H5N1 High Pathogenicity Avian Influenza Viruses in Four Raptors and Two Geese in Japan in the Fall of 2022.

In the fall of 2022, high pathogenicity avian influenza viruses (HPAIVs) were detected from raptors and geese in Japan, a month earlier than in past years, indicating a shift in detection patterns. In this study, we conducted a phylogenetic analysis on H5N1 HPAIVs detected from six wild birds during the 2022/2023 season to determine their genetic origins. Our findings revealed that these HPAIVs belong to the G2 group within clade 2.3.4.4b, with all isolates classified into three subgroups: G2b, G2d, and G2c. The genetic background of the G2b virus (a peregrine falcon-derived strain) and G2d viruses (two raptors and two geese-derived strains) were the same as those detected in Japan in the 2021/2022 season. Since no HPAI cases were reported in Japan during the summer of 2022, it is probable that migratory birds reintroduced the G2b and G2d viruses. Conversely, the G2c virus (a raptor-derived strain) was first recognized in Japan in the fall of 2022. This strain might share a common ancestor with HPAIVs from Asia and West Siberia observed in the 2021/2022 season. The early migration of waterfowl to Japan in the fall of 2022 could have facilitated the early invasion of HPAIVs.

Host-associated genetic differentiation and origin of a recent host shift in the generalist parasitic weed Phelipanche ramosa.

Branched broomrape, Phelipanche ramosa (L.) Pomel, is a globally distributed parasitic weed of economic importance. In Europe, where it is native, it can infest several crops, notably tomato, tobacco, and hemp. In western France, it has recently adapted to a new host crop, oilseed rape, causing substantial damage. The aim of this study was to investigate the evolutionary relationships and genetic differentiation among P. ramosa populations infesting different hosts. We collected 1611 P. ramosa samples from 109 fields cultivated with six different crops (oilseed rape, tobacco, hemp, tomato, lentil, and celery) and distributed among six European countries. All samples were genotyped for ten microsatellite loci and a subset of samples was sequenced for two nuclear genes and two chloroplast genes. Genetic differentiation among populations was high (F ST = 0.807) and mainly driven by differentiation among different host crops, with no significant geographic structure. Genetic structure analysis identified up to seven biologically meaningful clusters that matched with host crops of origin. Reconstructed networks of sequence haplotypes and multilocus SSR genotypes showed a large genetic divergence between samples collected on oilseed rape and samples collected on other crops. The phylogeny inferred from DNA sequences placed samples collected from oilseed rape as a basal lineage. Approximate Bayesian Computations were used to compare different evolutionary scenarios of divergence among the three main genetic clusters, associated, respectively, with oilseed rape, tobacco, and hemp as host crops. The best-supported scenario indicated that P. ramosa infesting oilseed rape derived recently from an ancient, unknown lineage. Our results suggest that a more complete description of the genetic diversity of P. ramosa is still needed to uncover the likely source of the recent adaptation to oilseed rape and to anticipate future new host shifts.

Spread of the Zoonotic Nematode Baylisascaris procyonis into a Naive Raccoon Population

The raccoon roundworm (Baylisascaris procyonis), a gastrointestinal nematode of the raccoon (Procyon lotor), may cause a severe form of larva migrans in humans, which can lead to death or permanent neurological damage. Although roundworms were inadvertently introduced to Europe alongside their raccoon hosts, the parasite is not present in every raccoon population. It is important to understand the geographic distribution of B. procyonis, as early and rapid treatment can prevent severe pathologies in humans. We present evidence for the roundworm spreading into a naive raccoon population through natural dispersal of infected raccoons. We sampled 181 raccoons from Saxony-Anhalt, a German federal state containing contact zones of different raccoon populations, two of which were previously free of the parasite. We screened the raccoons for roundworms and used microsatellite-based assignment tests to determine the genetic origin of the raccoons and their parasites. We detected roundworms in 16 of 45 raccoons sampled in a previously roundworm-free area in the northern part of the state. The largest proportion of the genetic ancestry (≥ 0.5) of the 16 raccoon hosts was assigned to the previously naive raccoon population. Conversely, the genetic ancestry of almost all the roundworms was assigned to the nearest roundworm population in the southern part of the state. Infected raccoons have, therefore, spread to the north of the state, where they interbred with and infected local raccoons. It seems likely that the roundworms will continue to spread. Health authorities should consider continuous surveillance programmes of naive populations and raise public awareness.

Initiatives to promote access to medicines after publication of the Brazilian Policy on the Comprehensive Care of People with Rare Diseases

BackgroundRare diseases affect a small number of people compared to prevalent diseases. The vast majority of these diseases are of genetic origin, have no cure, are chronic and can lead to death. Although the right to access medicines is included in the constitutionally guaranteed right to health in Brazil, problems in the supply of medicines for rare diseases are reported in the country. This study aimed to describe and analyse the initiatives to promote access to medicines for treating rare diseases in the Unified Health System, Brazil, after the publication of the Brazilian Policy on the Comprehensive Care of People with Rare Diseases. Based on the model published by the WHO Regional Office for Europe, which described access to medicines in prelaunch, perilaunch and postlaunch policies, the initiatives referring to each category were summarized based on documentary research searched in online databases from January 2014 to December 2020.ResultsDifferent actions and policy interventions were identified, which went through the expansion of resources for research and development, health regulations, incorporation of new drugs, review and publication of clinical guidelines, and expansion of the network of care facilities by the Ministry of Health. On the other hand, aspects related to care policies, pricing methods, technological development, and development of pharmaceutical service processes were not implemented.ConclusionsAlthough it is impossible to determine the explicit motivation of such actions concerning the Policy, its publication certainly was a landmark in Brazilian society, allowing greater recognition of the needs of rare disease patients and the specificities of treatment’. However, this study suggests that the steps that make up the life cycle of medicines are not linked, lacking articulation and integration of the care network, and consequently, there is no evidence that rare disease policy publication has generated a broad impact on the promotion of access to medicines to treat rare diseases in Brazil.

Placental and genetic origins of fetal growth restriction are independent and may overlap.

Placental and genetic origins of fetal growth restriction are independent and may overlap.

The microtubule signature in cardiac disease: etiology, disease stage, and age dependency

Employing animal models to study heart failure (HF) has become indispensable to discover and test novel therapies, but their translatability remains challenging. Although cytoskeletal alterations are linked to HF, the tubulin signature of common experimental models has been incompletely defined. Here, we assessed the tubulin signature in a large set of human cardiac samples and myocardium of animal models with cardiac remodeling caused by pressure overload, myocardial infarction or a gene defect. We studied levels of total, acetylated, and detyrosinated α-tubulin and desmin in cardiac tissue from hypertrophic (HCM) and dilated cardiomyopathy (DCM) patients with an idiopathic (n = 7), ischemic (n = 7) or genetic origin (n = 59), and in a pressure-overload concentric hypertrophic pig model (n = 32), pigs with a myocardial infarction (n = 28), mature pigs (n = 6), and mice (n = 15) carrying the HCM-associated MYBPC32373insG mutation. In the human samples, detyrosinated α-tubulin was increased 4-fold in end-stage HCM and 14-fold in pediatric DCM patients. Acetylated α-tubulin was increased twofold in ischemic patients. Across different animal models, the tubulin signature remained mostly unaltered. Only mature pigs were characterized by a 0.5-fold decrease in levels of total, acetylated, and detyrosinated α-tubulin. Moreover, we showed increased desmin levels in biopsies from NYHA class II HCM patients (2.5-fold) and the pressure-overload pig model (0.2–0.3-fold). Together, our data suggest that desmin levels increase early on in concentric hypertrophy and that animal models only partially recapitulate the proliferated and modified tubulin signature observed clinically. Our data warrant careful consideration when studying maladaptive responses to changes in the tubulin content in animal models.Graphical

Muscle magnetic resonance imaging of a large cohort of distal hereditary motor neuropathies reveals characteristic features useful for diagnosis

Distal motor neuropathies (dHMN) are an heterogenous group of diseases characterized by progressive muscle weakness affecting predominantly the distal muscles of the lower and upper limbs. Our aim was to study the imaging features and pattern of muscle involvement in muscle magnetic resonance imaging (MRI) in dHMN patients of suspected genetic origin (dHMN). We conducted a retrospective study collecting clinical, genetic and muscle imaging data. Muscle MRI included T1-weighted and T2 weighted Short Tau Inversion Recovery images (STIR-T2w) sequences. Muscle replacement by fat was quantified using the Mercuri score. Identification of selective patterns of involvement was performed using hierarchical clustering. Eighty-four patients with diagnosis of dHMN were studied. Fat replacement was predominant in the distal lower leg muscles (82/84 cases), although also affected thigh and pelvis muscles. Asymmetric involvement was present in 29% of patients. The superficial posterior compartment of the leg, including the soleus and gastrocnemius muscles, was the most affected area (77/84). We observed a reticular pattern of fatty replacement progressing towards what is commonly known as “muscle islands” in 79.8%. Hyperintensities in STIR-T2w were observed in 78.6% patients mainly in distal leg muscles. Besides features common to all individuals, we identified and describe a pattern of muscle fat replacement characteristic of BICD2, HSPB1 and DYNC1H1 patients. We conclude that muscle MRI of patients with suspected dHMN reveals common features helpful in diagnosis process.

Global genomic signature reveals the evolution of fall armyworm in the Eastern hemisphere.

The major plant pest fall armyworm (FAW), Spodoptera frugiperda, is native to the Americas and has colonized Africa and Asia within the Eastern hemisphere since 2016, causing severe damage to multiple agricultural crop species. However, the genetic origin of these invasive populations requires more in-depth exploration. We analysed genetic variation across the genomes of 280 FAW individuals from both the Eastern hemisphere and the Americas. The global range-wide genetic structure of FAW shows that the FAW in America has experienced deep differentiation, largely consistent with the Z-chromosomal Tpi haplotypes commonly used to differentiate 'corn-strain' and 'rice-strain' populations. The invasive populations from Africa and Asia are different from the American ones and have a relatively homogeneous population structure, consistent with the common origin and recent spreading from Africa to Asia. Our analyses suggest that north- and central American 'corn-strain' FAW are the most likely sources of the invasion into the Eastern hemisphere. Furthermore, evidence based on genomic, transcriptomic and mitochondrial haplotype network analyses indicates an earlier, independent introduction of FAW into Africa, with subsequent migration into the recent invasive population.

Whole Exome-Wide Association Identifies Rare Variants in GALNT9 Associated with Middle Eastern Papillary Thyroid Carcinoma Risk.

Papillary thyroid carcinoma (PTC) is the commonest thyroid cancer. The majority of inherited causes of PTC remain elusive. However, understanding the genetic underpinnings and origins remains a challenging endeavor. An exome-wide association study was performed to identify rare germline variants in coding regions associated with PTC risk in the Middle Eastern population. By analyzing exome-sequencing data from 249 PTC patients (cases) and 1395 individuals without any known cancer (controls), GALNT9 emerged as being strongly associated with rare inactivating variants (RIVs) (4/249 cases vs. 1/1395 controls, OR = 22.75, p = 5.09 × 10-5). Furthermore, three genes, TRIM40, ARHGAP23, and SOX4, were enriched for rare damaging variants (RDVs) at the exome-wide threshold (p < 2.5 × 10-6). An additional seven genes (VARS1, ZBED9, PRRC2A, VWA7, TRIM31, TRIM40, and COL8A2) were associated with a Middle Eastern PTC risk based on the sequence kernel association test (SKAT). This study underscores the potential of GALNT9 and other implicated genes in PTC predisposition, illuminating the need for large collaborations and innovative approaches to understand the genetic heterogeneity of PTC predisposition.

Genetic Diversity of Apple Clonal Rootstocks from the Collection of the Michurinsk State Agrarian University Based on SSR Markers.

The Michurinsk State Agrarian University (Michurinsk SAU) is one of the leading centers for breeding apple clonal rootstocks. A diverse collection of apple rootstocks, founded in 1930s by V.I. Budagovsky, is maintained at the Michurinsk SAU. In the present study, 87 rootstocks from this collection were analyzed using 18 SSR markers to assess their genetic diversity and relatedness. The detected polymorphism level was rather high compared to the previous estimates of apple rootstock genetic variability. A total of 199 alleles were detected with an average of 11.1 alleles per locus. Among the detected alleles, 67 (33.67%) were rare and 43 (21.61%) were unique. The average PIC value was 0.73, and the expected and observed heterozygosity averaged 0.76 and 0.69, respectively. All the studied accessions except two could be identified with the used marker set. Cluster analysis revealed several groups according to the rootstocks' pedigrees and genetic origin. Furthermore, Structure analysis revealed two main groups of the studied rootstock accessions. No significant differentiation of the studied sample according to dwarfing ability was detected, while weak differentiation was detected according to leaf color. SSR genotyping data can be used for rootstock fingerprinting and pedigree verification and will facilitate collection management. In addition, data on the genetic diversity and structure of the studied collection may be useful for further development of the Michurinsk SAU rootstock breeding program.

Phenolic compounds of sorghum [Sorghum bicolor (L.) Moench] and their allelopathic effect

Purpose. To establish the quantitative composition of phytochemicals containing in vegetative and generative organs of sugar sorghum hybrids with high and medium sugar content ‘Sugargraze ARG’ (Argentina), ‘Sioux’ and ‘Mohawk’ (USA) and ‘Ananas’ and ‘Medovyi’ (Ukraine) and their allelopathic effect&#x0D; Methods. Allelopathic, physiological-biochemical, agrochemical and statistical methods were used. The content of phytochemicals in the vegetative and generative organs of the studied sugar sorghum hybrids was determined by the extraction method.&#x0D; Results. A high concentration of sorghum phenolic substances in the seeds at the mature plant stage was found. However, their concentration was species specific and depended on their quantitative component in the process of morphogenesis of vegetative and generative organs of sorghum of different genetic origin. The analysis of the total content of phytochemical compounds in the studied hybrids showed an increase in their number at the end of the vegetation season. The research was conducted in vitro. The manifestation of phenolic compounds was observed through manifestation of the allelopathic effect of cultivated sorghum plants. It was found that on the 7th day of cultivation, the plants actively secreted phenolic compounds; the increase in the number of leaves and the height of plants in hybrids did not change and amounted to 3–5 and 1.6–2.0 cm, respectively. On the 14th day of the experiment, the phenolic spots grew significantly, and yellowing of the lower leaves appeared. In the process of morphogenesis of sorghum plants (during 21 days), a more intense release of phenolic compounds led to suppression and slowing down of growth and subsequently to the death of the clone, regardless of the genetic origin of the hybrids. Phenolic compositions also influenced the formation of the root system of cultivated sorghum plants. A significant decrease in the number of lateral roots and the length of the root system was noted in all studied hybrids.&#x0D; Conclusions. The highest content of phenolic compounds was found in the seeds (grain) and stems of the studied sorghum hybrids. Thus, the quantitative composition of glycosides and tannins was 34–39 and 5.5–6.9 %, respectively, in the seeds and 25–29 and 0.3–1.4 %, respectively, in the stems of the studied hybrids. The highest content of hydroxycinnamic acids (from 7 % to 14 %) was found in the leaves of the studied sorghum hybrids. Phenolic compositions under in vitro conditions cause stress, which slows down the growth and development of cultivated plants, and subsequently lead to the death of clones.

Genome Sequencing Provides Novel Insights into Mudflat Burrowing Adaptations in Eel Goby Taenioides sp. (Teleost: Amblyopinae).

Amblyopinae is one of the lineage of bony fish that preserves amphibious traits living in tidal mudflat habitats. In contrast to other active amphibious fish, Amblyopinae species adopt a seemly more passive lifestyle by living in deep burrows of mudflat to circumvent the typical negative effects associated with terrestriality. However, little is known about the genetic origin of these mudflat deep-burrowing adaptations in Amblyopinae. Here we sequenced the first genome of Amblyopinae species, Taenioides sp., to elucidate their mudflat deep-burrowing adaptations. Our results revealed an assembled genome size of 774.06 Mb with 23 pseudochromosomes anchored, which predicted 22,399 protein-coding genes. Phylogenetic analyses indicated that Taenioides sp. diverged from the active amphibious fish of mudskipper approximately 28.3 Ma ago. In addition, 185 and 977 putative gene families were identified to be under expansion, contraction and 172 genes were undergone positive selection in Taenioides sp., respectively. Enrichment categories of top candidate genes under significant expansion and selection were mainly associated with hematopoiesis or angiogenesis, DNA repairs and the immune response, possibly suggesting their involvement in the adaptation to the hypoxia and diverse pathogens typically observed in mudflat burrowing environments. Some carbohydrate/lipid metabolism, and insulin signaling genes were also remarkably alterated, illustrating physiological remolding associated with nutrient-limited subterranean environments. Interestingly, several genes related to visual perception (e.g., crystallins) have undergone apparent gene losses, pointing to their role in the small vestigial eyes development in Taenioides sp. Our work provide valuable resources for understanding the molecular mechanisms underlying mudflat deep-burrowing adaptations in Amblyopinae, as well as in other tidal burrowing teleosts.

Characterization of the genetic composition and establishment of a core collection for the INERA Robusta coffee (Coffea canephora) field genebank from the Democratic Republic of Congo

Cultivation of Robusta coffee is likely to gain importance because of its high disease resistance and climate envelope. Robusta coffee genetic resources conserved in field genebanks can play an important role to further improve its cupping quality and other agronomic traits, but such Coffea canephora collections are limited and still poorly characterized. In this study, we characterized the genetic composition of the historically important but until recently neglected INERA Coffee Collection in Yangambi (the Democratic Republic of Congo). We used GBS to discover genome-wide genetic diversity, created and validated a novel multiplex amplicon sequencing (HiPlex) screening assay to genetically screen 730 coffee shrubs of the Yangambi Coffee Collection, grouped clonal material and delineated 263 accessions with unique genetic fingerprints. Comparison to reference material of three genetic origins revealed that the majority of the Yangambi accessions were assigned a ‘Lula’ cultivar origin, four accessions were assigned to Congolese subgroup A and nine accessions were most closely related to local wild accessions. About one-quarter of the accessions was likely derived from hybridization between these groups, which could result from seed-based propagation of the collection, breeding efforts, or natural cross-pollination. Parental analyses discovered eight preferentially used accessions, which may correspond to historically selected founders, or direct descendants thereof, whose seed material was once widely used to establish coffee plantations. Finally, two core collections were proposed using the maximization strategy (CC-I; 100 accessions) and genetic distance method (CC-X; 10 accessions). Our study demonstrates a method for the genetic characterization of Robusta coffee collections in general and contributes to the re-evaluation and exploration of the Robusta coffee genetic resources in the Democratic Republic of the Congo in particular.

Prediction of Parkinson’s disease pathogenic variants using hybrid Machine learning systems and radiomic features

PurposeIn Parkinson’s disease (PD), 5–10% of cases are of genetic origin with mutations identified in several genes such as leucine-rich repeat kinase 2 (LRRK2) and glucocerebrosidase (GBA). We aim to predict these two gene mutations using hybrid machine learning systems (HMLS), via imaging and non-imaging data, with the long-term goal to predict conversion to active disease. MethodsWe studied 264 and 129 patients with known LRRK2 and GBA mutations status from PPMI database. Each dataset includes 513 features such as clinical features (CFs), conventional imaging features (CIFs) and radiomic features (RFs) extracted from DAT-SPECT images. Features, normalized by Z-score, were univariately analyzed for statistical significance by the t-test and chi-square test, adjusted by Benjamini-Hochberg correction. Multiple HMLSs, including 11 features extraction (FEA) or 10 features selection algorithms (FSA) linked with 21 classifiers were utilized. We also employed Ensemble Voting (EV) to classify the genes. ResultsFor prediction of LRRK2 mutation status, a number of HMLSs resulted in accuracies of 0.98 ± 0.02 and 1.00 in 5-fold cross-validation (80% out of total data points) and external testing (remaining 20%), respectively. For predicting GBA mutation status, multiple HMLSs resulted in high accuracies of 0.90 ± 0.08 and 0.96 in 5-fold cross-validation and external testing, respectively. We additionally showed that SPECT-based RFs added value to the specific prediction of of GBA mutation status. ConclusionWe demonstrated that combining medical information with SPECT-based imaging features, and optimal utilization of HMLS can produce excellent prediction of the mutations status in PD patients.

Geochemical characteristics and ore-forming mechanism of Luodian nephrite deposit, Southwest China and comparison with other nephrite deposits in Asia

A nephrite deposit was recently discovered in Luodian, Guizhou Province, which belongs to the South China Plate and is located in the eastern Tethys tectonic domain. This study examines systematically the geochemical characteristics and mineralization mechanism of Luodian nephrite using various analytical techniques including polarized light microscopy, scanning electron microscopy, electron probe microanalysis, and laser ablation-inductively coupled plasma-mass spectrometry. The results show that the main mineral of Luodian nephrite is tremolite, and the secondary minerals include diopside, calcite, quartz, albite, talc, and iron and manganese oxides. The tremolite was present in three morphological forms which have the characteristics of multi-period mineralization. The Mg2+/(Mg2++Fe2+) ratio indicates that the Luodian nephrite deposit is a dolomite-related type deposit. The trace elements of Cr, Ni, and Co, and the ratios of Rb/Sr and Rb/Ba are much lower than those serpentinite-related type nephrite, and are within the range of those for basic magma contact metasomatic nephrite. The rare earth elements (REEs) show that the formation of Luodian nephrite originates from metasomatism of sedimentary rocks. Curves for the distribution of the chondrite-normalized REE pattern and the characteristics of the REEs in nephrite are identical to those for marble or limestone, and are clearly different from those for diabase, indicating that the formation of nephrite occurrs closer to the surrounding rock. Combined with chemical analyses and a geological survey, the results show that Luodian nephrite was formed by the contact metasomatism of basic diabase and carbonate rock during the Indosinian-Yanshannian (Late Triassic to Cretaceous) period. The diabase magma provided a high-temperature environment and the Si hydrothermal environment; the presence of the carbonate rock facilitated Ca and Mg to form nephrite under specific physical and chemical conditions. The comparison of geochemical compositions can help to distinguish the genetic type, reaction mechanism and origin characteristics of nephrite deposits. These results provide theoretical guidance for the search for nephrite deposits of dolomite-related type origin.

Genetic basis and origin of resistance to acetolactate synthase inhibitors in Amaranthus palmeri from Spain and Italy.

Amaranthus palmeri is an aggressive annual weed native to the United States, which has become invasive in some European countries. Populations resistant to acetolactate synthase (ALS) inhibitors have been recorded in Spain and Italy, but the evolutionary origin of the resistance traits remains unknown. Bioassays were conducted to identify cross-resistance to ALS inhibitors and a haplotype-based genetic approach was used to elucidate the origin and distribution of resistance in both countries. Amaranthus palmeri populations were resistant to thifensulfuron-methyl and imazamox, and the 574-Leu mutant ALS allele was found to be the main cause of resistance among them. In two Spanish populations, 376-Glu and 197-Thr mutant ALS alleles were also found. The haplotype analyses revealed the presence of two and four distinct 574-Leu mutant haplotypes in the Italian and Spanish populations, respectively. None was common to both countries, but some mutant haplotypes were shared between geographically close populations or between populations more than 100 km apart. Wide genetic diversity was found in two very close Spanish populations. ALS-resistant A. palmeri populations were introduced to Italy and Spain from outside Europe. Populations from both countries have different evolutionary histories and originate from independent introduction events. ALS resistance then spread over short and long distances by seed dispersal. The higher number and genetic diversity among mutant haplotypes from the Spanish populations indicated recurrent invasions. The implementation of control tactics to limit seed dispersal and the establishment of A. palmeri is recommended in both countries. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Insights on the Formation Conditions of Manganese Oxides from Crimora, VA (USA)

Many regions of the United States contain manganese deposits economically valuable in New England, Appalachian, and Piedmont regions in the Eastern United States, in Northern Arkansas, and, to a small extent, in Central–Western California. Mn oxide/hydroxide (commonly referred to as Mn oxide minerals) are found in a wide variety of geological settings and occur as fine-grained aggregates, veins, marine and freshwater nodules and concretions, crusts, dendrites, and coatings on rock surfaces (e.g., desert varnish). How manganese oxides form and what mechanisms determine which oxides are likely to form are limited and still debated. This paper focuses on Mn oxides collected at the southern bound of the abandoned open-pit site called Crimora Mine (Augusta County, Virginia). This study uses mineralogical and chemical features to shed light on the origin of manganese deposits in Crimora along the western foot of the Blue Ridge in South–West Virginia. We report the first detailed study on the genesis of the Crimora manganese deposit conducted since the mine was closed in the 1950s. Crimora Mine sample is dark black fine- to medium-grained round and oblong nodules coated with a fine-grained intermix of yellowish earthy limonite, clays, and quartz. Scanning electron microscopy (SEM) revealed that the Crimora Mn-oxides exhibit concentric layering, breccia-like matrices, and veins. X-ray powder diffraction (XRPD) identified the set of Mn minerals as hollandite and birnessite. The concentration and range of dissolved chemical species in freshwater, seawater, and hydrothermal depositional fluids impart a geochemical signature to the Mn-oxides, providing a diagnostic tool to shed light on their genetic origin. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the Crimora manganese oxides shows Mn, Fe, and Ti, as well as trace elements such as Co, Ba, Y, Zn, Cr, Ni, Tl, La, V, and Li. A bivariate analysis based on the geochemical correlation of Mn and other common substituting cations (e.g., Fe, Co, Ti) shows a mixed genesis in different environments with varying biological and sedimentary supergene (freshwater and marine) conditions. These data suggest that the Mn-rich deposit in Crimora, VA, was formed in a continental margin environment of surficial deposits and reprecipitated in mixed biogenic and supergene conditions.