Separate Origins Research Articles

Hidden Local Symmetry Breaking in a Kagome-Lattice Magnetic Weyl Semimetal.

Exploring the relationship between intriguing physical properties and structural complexity is a central topic in studying modern functional materials. Co3Sn2S2, a newly discovered kagome-lattice magnetic Weyl semimetal, has triggered intense interest owing to the intimate coupling between topological semimetallic states and peculiar magnetic properties. However, the origins of the magnetic phase separation and spin glass state below TC in this ordered compound are two unresolved yet important puzzles in understanding its magnetism. Here, we report the discovery of local symmetry breaking surprisingly co-emerges with the onset of ferromagnetic order in Co3Sn2S2, by a combined use of neutron total scattering and half-polarized neutron diffraction. An anisotropic distortion of the cobalt kagome lattice at the atomic/nano level is also found, with distinct distortion directions among the two Co1 and four Co2 atoms. The mismatch of local and average symmetries occurs below TC, indicating that Co3Sn2S2 evolves to an intrinsically lattice disordered system when the ferromagnetic order is established. The local symmetry breaking with intrinsic lattice disorder provides new understanding of the puzzling magnetic properties. Our density functional theory (DFT) calculation indicates that the local symmetry breaking is expected to reorient local ferromagnetic moments, unveiling the existence of the ferromagnetic instability associated with the lattice instability. Furthermore, DFT calculation unveils that the local symmetry breaking could affect the Weyl property by breaking the mirror plane. Our findings highlight the fundamentally important role that the local symmetry breaking plays in advancing our understanding on the magnetic and topological properties in Co3Sn2S2, which may draw attention to explore the overlooked local symmetry breaking in Co3Sn2S2, its derivatives and more broadly in other topological Dirac/Weyl semimetals and kagome-lattice magnets.

Characteristics and Formation of the Luzon Undercurrent in the Western North Pacific: Observational Study

AbstractThe subsurface circulation system in the western North Pacific is dominated by the convergence of the Luzon Undercurrent (LUC) and the Mindanao Undercurrent, which forms the basin‐scale eastward North Equatorial Undercurrent jets. The southward LUC, situated to the east of Luzon Island, plays a significant role in transporting subsurface waters equatorward in the western boundary of the subtropical North Pacific. Despite its crucial contributions to the water, heat, and energy distributions in the subsurface layer, its characteristics and formation mechanism remain unclear. In this study, we utilize monthly climatological temperature and salinity data and the derived geostrophic velocity to investigate the spatiotemporal variability of the LUC and its formation dynamics. The LUC transport exhibits weak seasonality and strong intra‐seasonal variation, peaking in May/June and October. The origin of the LUC is closely connected with the southward veering of the Deep North Equatorial Current (DNEC) off the Ryukyu Islands and the Luzon Strait middle‐layer outflow (LSMO). The DNEC dominates transport in the LUC, and the LSMO of the South China Sea (SCS) Intermediate Water contributes to the water mixing in the LUC. Locally, the appearance of the LUC is dynamically linked with the barotropic effect associated with the sea surface height gradient and the baroclinic effect raised from the downward tilting of the zonal isopycnal off the Philippine coast. Spatially, the core of the LUC shifts from in‐shore to off‐shore waters from May/June to October. This study reveals the spatiotemporal characteristics of the LUC and identifies its separate origins from the interior North Pacific and the SCS middle layer.

Separate origin of left external and internal carotid arteries directly from aortic arch in a patient with double outlet right ventricle

We report a case of a 1-year-old boy with double outlet right ventricle where computed tomography(CT) angiography incidentally demonstrated the separate origin of the left external and internal carotid arteries directly from the left-sided aortic arch with absence of a left common carotid artery. The case highlights the underlying embryological hypothesis as well as the importance of CT angiography in identifying anomalies of the aortic arch and arch vessels in the setting of complex congenital heart defects.

An Extremely Rare Presentation of Four Coronary Anomaly Patterns Originating from the Right Coronary Sinus

Background “Coronary anomaly” is defined as the coronary feature or pattern seen in <1% of the population. The most common CAAs are anomalies of origin, specifically having a separate LCX and LAD origin with an incidence of 0.41%. The second most common anomaly is the LCX arising from the RCA (0.37%). Treatment options include CABG, coronary unroofing, reimplantation, or medical therapy. Case Presentation. We present the case of an 85-year-old male who presents with an acute coronary syndrome who was found to have an extremely rare combination of different coronary anomaly patterns including left main coronary artery (LMCA) atresia, small LAD arising posteriorly from the right coronary cusp, anomalous left circumflex artery arising from the RCA, and an anomalous LAD arising from the left circumflex artery which is originating from the RCA. Conclusions To the best of our knowledge, this is the first case report to describe four coronary anomalies in a single patient. When CAAs are diagnosed, it is of utmost importance for cardiologists to do further imaging and workup that might include a stress test to be able to offer patients the best management options.

Abstract 5232: Next-generation sequencing revealed clonal architecture and faciliated diagnosis of patients with multiple lung tumors: An analysis of 12 cases

Abstract Diagnosing multiple lung tumors as multiple primary lung cancer (MPLC) or intrapulmonary metastasis (IPM) has important therapeutic implications. The clinical applicability of next-generation sequencing (NGS) has been explored, although there is currently no consensus regarding how to integrate its findings for cancer staging. We performed a retrospective analysis of the mutational landscape of 13 patients with multiple tumors and underwent surgery at Renmin Hospital of Wuhan University from Sep. 2018 to Dec. 2020.The cohort consisted mostly of women (11/13, 84.6%) and non-smokers (12/13, 92.3%). Median age was 58 years (range 26-71). No patient manifested relapse after a median follow-up duration of 11.2 months (range 8.2-36.0). NGS was performed with a large panel (≥ 350 genes) in most cases (11/13, 84.6%). Most nodules were invasive adenocarcinomas (25/41, 61.0%), followed by adenocarcinomas in situ (13/41, 31.7%), and minimally invasive adenocarcinomas (3/41, 7.3%). Four patients were clinically diagnosed with IPM, of whom 1 had only one nodule sequenced. Of the 12 patients with genomic profiles from multiple nodules, 10 (83.3%) had consistent NGS inference and clinical diagnosis of MPLC or IPM. Of the remaining two, P1 was clinically diagnosed with IPM but NGS did not detect any genomic aberrations from one nodule, which may have missed evidence that could have led to inference of clonal relationship. P8 was diagnosed with MPLC but had two nodules that harbored EGFR L858R mutation. NGS revealed clonal relationships that enabled high-confidence differential diagnosis in the concordant cases. For instance, the 3 nodules in P10 each harbored an oncogenic driver: EGFR exon 19 deletion, EGFR L858R, and ALK fusion, which were suggestive of tumor clones of separate origins. Similar mutual exclusion was also observed in P6 (EGFR exon 19 deletion vs L858R), P2 (EGFR exon 19 deletion vs MAP2K1), and P7 (2 EGFR exon 18 mutations G719A and E709 in one nodule vs EGFR E746_A750del in another). On the other hand, P9 illustrates a case of complex clonal architecture, in which 8 nodules were derived from 5 origins. Further analysis found that alterations in KRAS were associated with smaller nodule size, whereas those in TP53, CDKN2A, NKX2-1, or GNAS were associated with greater size.In summary, NGS achieved highly concordant MPLC/IPM differentiation with clinical diagnosis based on histopathologic and radiographic evidence. However, caution is warranted when NGS detects no aberration from any of the multiple sequenced nodules. Examination of the mutational landscape found that altered proto-oncogene KRAS was associated with smaller tumors whereas altered tumor suppressors TP53 and CDKN2A associated with smaller ones, suggesting different roles in these molecules play in tumor growth. Citation Format: Wenyang Jiang, Wei Wang, Luting Qiu, Xiao Zou, Zhiqiu Chen, Qing Geng. Next-generation sequencing revealed clonal architecture and faciliated diagnosis of patients with multiple lung tumors: An analysis of 12 cases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5232.

Luminous Millimeter, Radio, and X-Ray Emission from ZTF 20acigmel (AT 2020xnd)

Observations of the extragalactic (z = 0.0141) transient AT 2018cow established a new class of energetic explosions shocking a dense medium, producing luminous emission at millimeter and submillimeter wavelengths. Here we present detailed millimeter- through centimeter-wave observations of a similar transient, ZTF 20acigmel (AT 2020xnd), at z = 0.2433. Using observations from the NOrthern Extended Millimeter Array and the Very Large Array, we model the unusual millimeter and radio emission from AT 2020xnd under several different assumptions and ultimately favor synchrotron radiation from a thermal electron population (relativistic Maxwellian). The thermal electron model implies a fast but subrelativistic (v ≈ 0.3c) shock and a high ambient density (n e ≈ 4 × 103 cm−3) at Δt ≈ 40 days. The X-ray luminosity of L X ≈ 1043 erg s−1 exceeds simple predictions from the radio and UVOIR luminosity and likely has a separate physical origin, such as a central engine. Using the fact that month-long luminous (L ν ≈ 2 × 1030 erg s−1 Hz−1 at 100 GHz) millimeter emission appears to be a generic feature of transients with fast (t 1/2 ≈ 3 days) and luminous (M peak ≈ −21 mag) optical light curves, we estimate the rate at which transients like AT 2018cow and AT 2020xnd will be detected by future wide-field millimeter transient surveys such as CMB-S4 and conclude that energetic explosions in dense environments may represent a significant population of extragalactic transients in the 100 GHz sky.

A 33-Year-Old Man With Circumflex Aortic Arch and 4-cm Right Subclavian Artery Aneurysm

This is a 33-year-old man with CHARGE (coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities, ear abnormalities) syndrome and a history of double aortic arch causing tracheal and esophageal compression. Cross-sectional imaging showed a 40-mm right subclavian artery aneurysm with a dominant right vertebral artery coming off it, an aberrant left subclavian artery, and separate origins of the bilateral common carotid arteries from the aortic arch. He underwent total aortic arch replacement, providing a left-sided arch to relieve the compression of the trachea and esophagus with bypass to the right axillary artery and reimplantation of the vertebral arteries and bilateral common carotid arteries. https://www.jvascsurg.org/cms/asset/e03d8a09-b06a-40bd-93b5-aa10b3dc9e62/mmc1.mp4Loading ... Download .mp4 (150.74 MB) Help with .mp4 files Video 1

Chiral Posttranslational Modification to Lysine ε-Amino Groups.

The sophistication of proteomic analysis has revealed that protein lysine residues are posttranslationally modified by a variety of acyl groups. Protein lysine acetylation regulates metabolism, gene expression, and microtubule formation and has been extensively studied; however, the understanding of the biological significance of other acyl posttranslational modifications (PTMs) is still in its infancy. The acylation of lysine residues is mediated either by acyltransferase "writer" enzymes or by nonenzymatic mechanisms and hydrolase enzymes, termed "erasers", that cleave various acyl PTMs to reverse the modified state. We have studied the human lysine deacylase enzymes, comprising the 11 Zn2+-dependent histone deacetylases (HDACs) and the 7 NAD+-consuming sirtuins (SIRTs), over the past decade. We have thus developed selective inhibitors and molecular probes and have studied the acyl substrate scope of each enzyme using chemically synthesized peptide substrates and photo-cross-linking probes. Recently, we have turned our attention to PTMs containing a stereogenic center, such as ε-N-β-hydroxybutyryllysine (Kbhb) and ε-N-lactyllysine (Kla), that each comprise a pair of mirror image stereoisomers as modifications. Both modifications are found on histones, where they affect gene transcription in response to specific metabolic states, and they are found on cytosolic and mitochondrial enzymes involved in fatty acid oxidation (Kbhb) and glycolysis (Kla), respectively. Thus, chiral modifications to lysine side chains give rise to two distinct diastereomeric products, with separate metabolic origins and potentially different activities exhibited by writer and eraser enzymes. Lysine l-lactylation originates from l-lactate, a major energy carrier produced from pyruvate after glycolysis, and it is highly induced by metabolic states such as the Warburg effect. l-Lactate can possibly be activated by acyl-coenzyme A (CoA) synthetases and transferred to lysine residues by histone acetyltransferases such as p300. d-Lactylation, on the other hand, arises primarily from a nonenzymatic reaction with d-lactylglutathione, an intermediate in the glyoxalase pathway. In addition to their distinct origin, we found that both K(l-la) and K(d-la) modifications are erased by HDACs with different catalytic efficiencies. Also, K(l-bhb) and K(d-bhb) arise from different metabolites but depend on interconnected metabolic pathways, and the two stereoisomers of ε-N-3-hydroxy-3-methylglutaryllysine (Khmg) originate from a single precursor that may then be regulated differently by eraser enzymes. Distinguishing between the individual stereoisomers of PTMs is therefore of crucial importance. In the present Account, we will (1) revisit the long-standing evidence for the distinct production and dynamics of enantiomeric forms of chiral metabolites that serve as ε-N-acyllysine PTMs and (2) highlight the outstanding questions that arise from the recent literature on chiral lysine PTMs resulting from these metabolites.

Mitochondrial DNA diversity divulges high levels of haplotype diversity and lack of genetic structure in the Indian camels.

Camels represent an important genetic resource of the desert ecosystems of India, with the dromedary and Bactrian camels inhabiting the hot and cold deserts, respectively. This study is the first attempt to investigate mitochondrial DNA based genetic diversity in the Indian camel populations and explores their relationship in the context of global genetic diversity of all the three large camel species (Camelus ferus, Camelus bactrianus and Camelus dromedaries). A mitochondrial DNA fragment encompassing part of cytochrome b gene, tRNAThr, tRNAPro and the beginning of the control region was amplified and analyzed in 72 dromedary and 8 Bactrian camels of India. Sequence analysis revealed that the haplotype and nucleotide diversity (Hd: 0.937 and π: 0.00431) in the Indian dromedaries was higher than the indices reported so far for the dromedary or Bactrian camels across the globe. The corresponding values in the Indian Bactrian camels were 1.000 and 0.00393, respectively. Signals of population expansion were evident in the dromedaries of India on the basis of mismatch analysis and Fu's Fs values. The analysis of molecular variance attributed most of the genetic variance (92.15%) between the dromedary, wild Bactrian and domestic Bactrian camels indicating separate maternal origins. The existence of three mitochondrial lineages in the old world camels (C. bactrianus: Lineage A; C. ferus: Lineage B and C. dromedarius: Lineage C) was also substantiated by the topology of the Median-Joining network.

Reunion of Australasian Possums by Shared SINE Insertions.

Although first posited to be of a single origin, the two superfamilies of phalangeriform marsupial possums (Phalangeroidea: brushtail possums and cuscuses and Petauroidea: possums and gliders) have long been considered, based on multiple sequencing studies, to have evolved from two separate origins. However, previous data from these sequence analyses suggested a variety of conflicting trees. Therefore, we reinvestigated these relationships by screening n}{}sim200,000 orthologous short interspersed element (SINE) loci across the newly available whole-genome sequences of phalangeriform species and their relatives. Compared to sequence data, SINE presence/absence patterns are evolutionarily almost neutral molecular markers of the phylogenetic history of species. Their random and highly complex genomic insertion ensures their virtually homoplasy-free nature and enables one to compare hundreds of shared unique orthologous events to determine the true species tree. Here, we identify 106 highly reliable phylogenetic SINE markers whose presence/absence patterns within multiple Australasian possum genomes unexpectedly provide the first significant evidence for the reunification of Australasian possums into one monophyletic group. Together, our findings indicate that nucleotide homoplasy and ancestral incomplete lineage sorting have most likely driven the conflicting signal distributions seen in previous sequence-based studies. [Ancestral incomplete lineage sorting; possum genomes; possum monophyly; retrophylogenomics; SINE presence/absence.]

Delineation of Paraburkholderia tuberum sensu stricto and description of Paraburkholderia podalyriae sp. nov. nodulating the South African legume Podalyria calyptrata

Since the discovery of Paraburkholderia tuberum, an indigenous South African species and one of the first beta-rhizobia described, several other South African rhizobial Paraburkholderia species have been recognized. Here, we investigate the taxonomic status of 31 rhizobial isolates from the root nodules of diverse South African legume hosts in the Core Cape Subregion, which were initially identified as P. tuberum. These isolates originate from the root nodules of genera in the Papilionoideae as well as Vachellia karroo, from the subfamily Caesalpinioideae. Genealogical concordance analysis of five loci allowed delineation of the isolates into two putative species clusters (A and B). Cluster A included P. tuberum STM678T, suggesting that this monophyletic group represents P. tuberum sensu stricto. Cluster B grouped sister to P. tuberum and included isolates from the Paarl Rock Nature Reserve in the Western Cape Province. Average Nucleotide Identity (ANI) analysis further confirmed that isolates of Cluster A shared high genome similarity with P. tuberum STM678T compared to Cluster B and other Paraburkholderia species. The members of Cluster B associated with a single species of Podalyria, P. calyptrata. For this new taxon we accordingly propose the name Paraburkholderia podalyriae sp. nov., with the type strain WC7.3bT (= LMG 31413T; SARCC 750T). Based on our nodA and nifH phylogenies, P. podalyriae sp. nov. and strains of P. tuberum sensu stricto (including one from V. karroo) belong to symbiovar africana, the symbiotic loci of which have a separate evolutionary origin to those of Central and South American Paraburkholderia strains.

Issues of comparative Uralic and Altaic studies (10): On the local case markers in Mongolic

This paper discusses the diachronic status of the local case markers in Mongolic, as compared with the other “Micro-Altaic” languages. In spite of some striking superfi cial similarities, it is shown that the local case markers in Mongolic, Turkic, and Tungusic have separate origins, though it cannot be ruled out that they have secondarily infl uenced each other in the context of areal contacts. Mongolic has two secondary “dative” (dative-locative) markers, *-DUr and *-D-A-, of which the former is likely to be based on the spatial *dota-r(-) ‘inside’, while the latter involves a combination of the spatial formative *-d- with the primary “locative” (locative-dative) case marker *-A. The suffi xalization of the spatial *dota-r(-) in Mongolic is parallelled by the analogous development of the spatial *doo ‘inside’ in Tungusic. The formal similarity of the spatial roots *dota- and *doo can be accidental, but it could also refl ect a material connection of either the areal or the genetic type.

Genomic consequences of colonisation, migration and genetic drift in barn owl insular populations of the eastern Mediterranean.

The study of insular populations was key in the development of evolutionary theory. The successful colonisation of an island depends on the geographic context, and specific characteristics of the organism and the island, but also on stochastic processes. As a result, apparently identical islands may harbour populations with contrasting histories. Here, we use whole genome sequences of 65 barn owls to investigate the patterns of inbreeding and genetic diversity of insular populations in the eastern Mediterranean Sea. We focus on Crete and Cyprus, islands with similar size, climate and distance to mainland, that provide natural replicates for a comparative analysis of the impacts of microevolutionary processes on isolated populations. We show that barn owl populations from each island have a separate origin, Crete being genetically more similar to other Greek islands and mainland Greece, and Cyprus more similar to the Levant. Further, our data show that their respective demographic histories following colonisation were also distinct. On the one hand, Crete harbours a small population and maintains very low levels of gene flow with neighbouring populations. This has resulted in low genetic diversity, strong genetic drift, increased relatedness in the population and remote inbreeding. Cyprus, on the other hand, appears to maintain enough gene flow with the mainland to avoid such an outcome. Our study provides a comparative population genomic analysis of the effects of neutral processes on a classical island‐mainland model system. It provides empirical evidence for the role of stochastic processes in determining the fate of diverging isolated populations.

Prevalence and patterns of coronary artery anomalies in 28,800 adult patients undergoing angiography in a large tertiary care centre in India.

Coronary artery anomalies (CAAs) are a diverse group of disorders with varied clinical presentation and pathophysiological mechanisms. A majority of these anomalies are asymptomatic and often an incidental finding on coronary angiogram or autopsy. This retrospective study included 28,800 patients who underwent coronary angiography from 2016 to 2020. The coronary angiograms were reviewed by two independent reviewers and CAAs were documented. CAAs were classified into i) anomalies of coronary artery connection, ii) anomalies of intrinsic coronary arterial anatomy and iii) anomalies of myocardial/coronary artery interaction as proposed by the European Society of Cardiology. Of the 28,800 coronary angiograms, CAAs were present in 4.12% with anomalies in the left coronary artery (LCA) being most common. Anomalies of coronary artery connection were most common (48.48%) followed by anomalies of myocardial/coronary artery interaction (34.49%) and anomalies of intrinsic coronary artery anatomy (17.03%). Among anomalies of coronary artery connection, absent left main trunk or split LCA with separate origins of left anterior descending coronary artery and left circumflex coronary artery from the left coronary sinus of Valsalva (22.59%) was most common. An intramural course or "myocardial bridge" had an incidence of 1.16% while incidence of coronary artery fistulae (CAF) was 0.115%.

462 Accidental detection of an anomalous origin of the coronary arteries in a patient with STEMI: a case report

Abstract Coronary artery anomalies and variants are relatively uncommon congenital disorders of the coronary artery anatomy and constitute the second most common cause of sudden cardiac death in young competitive athletes. Normally there are two main coronary arteries, which stem from the sinuses of Valsalva and descend towards the cardiac apex. The most frequent anomalous origin of the coronary arteries associated with sudden cardiac death is the anomalous origin of a coronary artery from the contralateral sinus, particularly if the anomalous coronary artery has a course between the aorta and the pulmonary artery. The diagnosis of a coronary artery anomaly is insidious since patients are usually asymptomatic. Indeed, in most of the cases, coronary anomalies are discovered incidentally during coronary angiography or on autopsy following sudden cardiac death. However, in some cases, symptoms like angina, syncope, heart failure, and myocardial infarction may occur. We want to describe the case of a 54 years old man who went to another hospital of our district with chest pain. The EKG showed an infero-lateral STEMI. The patient underwent systemic thrombolysis complicated by arrhythmic storm, treated with effective DC shock, then he was urgently transferred to our Hospital to perform a PCI rescue. The coronary angiography showed a critical stenosis of the right coronary artery, treated with the implantation of a zotarolimus-eluting coronary stent system. Surprisingly, an abnormal origin of the anterior interventricular artery and circumflex artery from seperated hosts in the right coronary sinus was detected. A computed tomography showed the separated origin of the right coronary artery and the left main from the right coronary sinus; moreover, the left main presented a retroaortic course between the bulb and the left atrium; the left anterior intraventricular artery run anterior to the aortic root. During hospitalization, a diagnosis of diabetes was made with consequent setting of adequate hypoglycemic therapy. Serial echocardiograms showed an improval in the ejection fraction (from 35–40% to 50%). The patient was discharged in well clinical conditions and 1 month later at the follow-up, during an outpatient visit, he was fully asymptomatic. The dynamic EKG according to Holter showed rare isolated ventricular beats; laboratory tests were normal. The anomalous origin of a coronary ostium from the contralateral sinus is the most frequently anomaly which is associated with sudden cardiac death, in particular when the left coronary artery origins from the right sinus. The rapid advancement of the imaging techniques, including CT, CMR, intravascular ultrasound, and optical coherence tomography, have provided us with a wealth of new information on this subject. Coronary artery CT offers the best performance in terms of spatial resolution, acquisition time, and image contrast but the use is limited due the dose of ionizing radiation and the use of contrast agents, in particular taking into account that most patients are young. CMR is capable of visualizing the origin of the coronary arteries non-invasively, without use of ionizing radiation and contrast agents. Currently however, due to spatial resolution, the capability of CMR to visualize smaller coronary branches is still a limiting factor preventing full assessment of coronary arteries using this modality. Developments and more widespread access to advanced cardiac imaging will undoubtedly lead to earlier diagnoses. The taxonomies of the anomalous origin of coronary arteries are inconsistent and complex and so we want to make our contribution to the register of cases of abnormal origin of coronary arteries for the risk of sudden cardiac death and ischaemic events related to.

Genomic analysis of the polyamine biosynthesis pathway in duckweed Spirodela polyrhiza L.: presence of the arginine decarboxylase pathway, absence of the ornithine decarboxylase pathway, and response to abiotic stresses

Main conclusionIdentification of the polyamine biosynthetic pathway genes in duckweed S. polyrhiza reveals presence of prokaryotic as well as land plant-type ADC pathway but absence of ODC encoding genes. Their differential gene expression and transcript abundance is shown modulated by exogenous methyl jasmonate, salinity, and acidic pH.Genetic components encoding for polyamine (PA) biosynthetic pathway are known in several land plant species; however, little is known about them in aquatic plants. We utilized recently sequenced three duckweed (Spirodela polyrhiza) genome assemblies to map PA biosynthetic pathway genes in S. polyrhiza. PA biosynthesis in most higher plants except for Arabidopsis involves two pathways, via arginine decarboxylase (ADC) and ornithine decarboxylase (ODC). ADC-mediated PA biosynthetic pathway genes, namely, one arginase (SpARG1), two arginine decarboxylases (SpADC1, SpADC2), one agmatine iminohydrolase/deiminase (SpAIH), one N-carbamoyl putrescine amidase (SpCPA), three S-adenosylmethionine decarboxylases (SpSAMDc1, 2, 3), one spermidine synthase (SpSPDS1) and one spermine synthase (SpSPMS1) in S. polyrhiza genome were identified here. However, no locus was found for ODC pathway genes in this duckweed. Hidden Markov Model protein domain analysis established that SpADC1 is a prokaryotic/biodegradative type ADC and its molecular phylogenic classification fell in a separate prokaryotic origin ADC clade with SpADC2 as a biosynthetic type of arginine decarboxylase. However, thermospermine synthase (t-SPMS)/Aculis5 genes were not found present. Instead, one of the annotated SPDS may also function as SPMS, since it was found associated with the SPMS phylogenetic clade along with known SPMS genes. Moreover, we demonstrate that S. polyrhiza PA biosynthetic gene transcripts are differentially expressed in response to unfavorable conditions, such as exogenously added salt, methyl jasmonate, or acidic pH environment as well as in extreme temperature regimes. Thus, S. polyrhiza genome encodes for complete polyamine biosynthesis pathway and the genes are transcriptionally active in response to changing environmental conditions suggesting an important role of polyamines in this aquatic plant.

Water-Induced Chiral Separation on a Au(111) Surface.

Facing the scientific question of the origin of chirality in life, water is considered to play a crucial role in driving many biologically relevant processes in vivo. Water has been demonstrated in vitro to be related to chiral generation, amplification, and inversion, while the underlying mechanism is still not fully understood. Real-space evidence at the single-molecule level is thus urgently required to understand the role of water molecules in biomolecular chirality related issues. Herein, we choose one of the RNA bases, the biomolecule uracil (U), which self-assembles into racemic hydrogen-bonded structures. Upon water exposure, surprisingly, racemic structures could be transformed to homochiral water-involved structures, resulting in an unexpected chiral separation on the surface. The origin of chiral separation is due to preferential binding between water and the specific site of U molecules, which leads to the formation of the energetically most favorable homochiral (U-H2O-U)2 cluster as seed for subsequent chiral amplification. Such a water-driven self-assembly process may also be extended to other biologically relevant systems such as amino acids and sugars, which would provide general insights into the role that water molecules may play in the origin of homochirality in vivo.

From innate to adaptive immunity: Abomasal transcriptomic responses of merino sheep to Haemonchus contortus infection

Although many important mediators and critical pathways are found to be involved in host immune responses to Haemonchus contortus infection, the initial responses to infection in the naïve and in the previously exposed state have not been compared at the transcriptional level. To further understand the development of adaptive immunity to H. contortus infection, we compared the early abomasal gene expression patterns between a primary and a tertiary challenge for four lines of sheep to discover differentially expressed genes (DEGs). The sheep were from the resistant (R) and susceptible (S) lines of two flocks of sheep selected for divergent responses to gastro-intestinal parasites (HSF and TSF). The flocks have separate origins and were initiated using two different strains of Merino sheep. One of the DEGs, mast cell proteinase 1, had significantly lower expression in tertiary compared to primary infections for all four lines of sheep. This gene was not identified in previous studies where resistant and susceptible sheep samples were compared within infection time points. Comparing the differentially expressed genes (DEGs) for the two R lines reveals that responses differed very little between the primary and tertiary challenges for HSFR and only two genes were identified, in contrast to the TSFR where there were 134 genes identified including the two identified using the HSFR animals. Similarly, comparing the primary and tertiary challenges for HSFS identified 15 DEGs, whilst for TSFS there were 128 DEGs identified. It is surprising that so few genes respond similarly between the two challenge regimes across the four lines of sheep, and suggests significant differences in immune mechanisms between the two flocks (across the lines) and also between the lines within flocks. Our results offer a quantitative snapshot comparing the transcriptome in the ovine abomasum between primary and tertiary infections with H. contortus in both genetically resistant and susceptible sheep.

A2A: 21 000 bulge stars from the ARGOS survey with stellar parameters on the APOGEE scale

Aims. Spectroscopic surveys have by now collectively observed tens of thousands of stars in the bulge of our Galaxy. However, each of these surveys had unique observing and data processing strategies that led to distinct stellar parameter and abundance scales. Because of this, stellar samples from different surveys cannot be directly combined. Methods. Here we use the data-driven method, The Cannon, to bring 21 000 stars from the ARGOS bulge survey, including 10 000 red clump stars, onto the parameter and abundance scales of the cross-Galactic survey, APOGEE, obtaining rms precisions of 0.10 dex, 0.07 dex, 74 K, and 0.18 dex for [Fe/H], [Mg/Fe], Teff, and log(g), respectively. The re-calibrated ARGOS survey – which we refer to as the A2A survey – is combined with the APOGEE survey to investigate the abundance structure of the Galactic bulge. Results. We find X-shaped [Fe/H] and [Mg/Fe] distributions in the bulge that are more pinched than the bulge density, a signature of its disk origin. The mean abundance along the major axis of the bar varies such that the stars are more [Fe/H]-poor and [Mg/Fe]-rich near the Galactic centre than in the outer bulge and the long bar region. The vertical [Fe/H] and [Mg/Fe] gradients vary between the inner bulge and the long bar, with the inner bulge showing a flattening near the plane that is absent in the long bar. The [Fe/H] − [Mg/Fe] distribution shows two main maxima, an ‘[Fe/H]-poor [Mg/Fe]- rich’ maximum and an ‘[Fe/H]-rich [Mg/Fe]-poor’ maximum, that vary in strength with position in the bulge. In particular, the outer long bar close to the Galactic plane is dominated by super-solar [Fe/H], [Mg/Fe]-normal stars. Stars composing the [Fe/H]-rich maximum show little kinematic dependence on [Fe/H], but for lower [Fe/H] the rotation and dispersion of the bulge increase slowly. Stars with [Fe/H] &lt; −1 dex have a very different kinematic structure than stars with higher [Fe/H]. Conclusions. Comparing with recent models for the Galactic boxy-peanut bulge, the abundance gradients and distribution, and the relation between [Fe/H] and kinematics suggests that the stars comprising each maximum have separate disk origins with the ‘[Fe/H]-poor [Mg/Fe]-rich’ stars originating from a thicker disk than the ‘[Fe/H]-rich [Mg/Fe]-poor’ stars.

Evolution of pegmatite ore-forming fluid: The Lijiagou spodumene pegmatites in the Songpan-Garze Fold Belt, southwestern Sichuan province, China

The late to post-tectonic Lijiagou spodumene pegmatites are located in the Ke’eryin orefield, which lies in the Triassic central Songpan-Garze Fold Belt (SGFB) in southwestern Sichuan Province, China. Fluid inclusion petrography, microthermometry and Raman spectroscopic analyses were carried out on quartz and spodumene in granites and four types of pegmatite in the Ke’eryin orefield. A Hydrothermal Diamond Anvil Cell (HDAC) was used to observe the microthermometric behavior of crystal-rich inclusions. Five types of fluid inclusions were identified. Crystal-rich inclusions (Type 1) in spodumene pegmatites were trapped at high temperature (658 to 741 °C) and high pressure (>4.7 kbar). Other inclusion types were found in granite and all types of pegmatite. Triphase CO2-H2O (CO2 + V + L, Type 2) inclusions show medium homogenization temperatures (324 to 339 °C), medium trapping pressures (2.09 to 2.54 kbar) and low to moderate salinities (3.1 to 11.3 wt% NaCl equiv). Biphase aqueous inclusions (L + V, Type 3) show similar homogenization temperatures (319 to 347 °C), and low to moderate salinities (5.5 to 18.0 wt% NaCl equiv). Monophase liquid CO2 (Type 4) inclusions have very low homogenization temperatures (15.4 to 19.1 °C). Monophase liquid H2O (Type 5) inclusions have moderate ice melting temperatures (–18.6 to –9.8 °C), and moderate salinities (18.4 to 18.5 wt% NaCl equiv). The various types of fluid inclusion reveal the P–T conditions of pegmatite formation, which records the transition from a magmatic to a hydrothermal environment and indicate that the ore-forming fluid resulted from the unmixing of magmatic melt. Fluid immiscibility is the key mechanism responsible for formation of the Lijiagou spodumene pegmatites and lithium mineral precipitation occurred from a high to medium temperature CO2-rich fluid. The absence of temperature and salinity gradients between granite and progressively more distal and evolved pegmatite compositions is inconsistent with formation of pegmatite magmas by fractional crystallization of granitic magmas, but consistent with separate anatectic origins of each type of pegmatite magma.