Mosaic Pattern Research Articles

First report of watermelon crinkle leaf-associated virus 1 (WCLaV-1) and WCLaV-2 infecting watermelon (Citrullus lanatus) in the United States.

Watermelon (Citrullus lanatus) and other cucurbits are cultivated globally, and Texas ranks among its top 5 producers in the U.S. In July 2020, plants with virus-like disease symptoms consisting of mild leaf crinkling and yellow mosaic patterns were observed in a 174-ha watermelon field in Burleson Co., TX; disease incidence was visually estimated at 5%. Total nucleic acids were extracted from leaf tissues of 5 randomly sampled plants (Dellaporta 1983) and their equimolar amounts were made into a composite sample that was used for cDNA library construction with TruSeq Stranded Total RNA with Ribo-Zero Plant Kit (Illumina). The cDNA library was sequenced on the Illumina NextSeq 500 platform, generating ~37M single-end reads (each 75 nt), which were analyzed as per Al Rwahnih et al. (2018). Of these, 58,200 and 27,500 reads mapped to the genomes of watermelon crinkle leaf-associated virus 1 (WCLaV-1) and WCLaV-2 (Xin et al. 2017), respectively, along with 4 other virus-specific reads (data not shown). The near complete RNA1-RNA3 segments of WCLaV-1 (354-652X) and WCLaV-2 (144-258X) were generated from the mapped reads and they shared ≥96% nt identities with published RNA segments of both viruses. The results were verified by RT-PCR using newly designed primers WCLaV-1vRP: 5'-GGTGAGTTAGTGTGTCTGAAGG/WCLaV-1cRP: 5'-GAGGTTGCCTGAGGTGATAAG to target 881 bp of the RNA1-encoded RNA-dependent RNA polymerase (RdRP), WCLaV-1vMP: 5'-GAAGGTTTGCTCCCTTGAAATG/WCLaV-1cMP: 5'-GACTGTGGCTGAAGAGTCTATG target 538 bp of the RNA2-encoded movement protein (MP), and WCLaV-1vNP: 5'-CGAATAGACTCTGGAGGGTAGA/WCLaV-1cMP: 5'-GAAAGCAAGAAAGCTGGCTAAA target 786 bp of the RNA3-encoded nucleoprotein (NP). Similarly, the WWCLaV-2-specific primers WCLaV-2vRP: 5'-GTCTCACATTCCTGCACTAACT/WCLaV-2cRP: 5'-ATCGGTCCTGGGTTATTTGTATC target 968 bp of the RdRP, WCLaV-2vMP: 5'-GACTTCAGAACCTCAACATCCA/WCLaV-2cMP: 5'-CAAGGGAGAGTGCTGACAAA target 562 bp of the MP, and WCLaV-2vNP: 5'-ATTCCCAGTGAGAGCAACAA/WCLaV-2cMP: 5'-GAGGTGGAGGTAGGAAAGAAAG target 449 bp of the NP. Fresh cDNA synthesized from the 5 samples with PrimeScript First Strand cDNA synthesis kit (Takara Bio) were tested by PCR with all 6 primer pairs using the PrimeSTAR GXL DNA Polymerase kit (Takara Bio). Three of the 5 samples were positive for both viruses and one sample was positive for each virus. The obtained products from 4 samples were cloned individually into pJET1.2/Blunt vector (Thermo Scientific, USA), followed by bidirectional Sanger-sequencing of the plasmids with the GenElute Five-Minute Plasmid Miniprep kit (Sigma-Aldrich). In pairwise comparisons, the partial RNA1-RNA3 sequences of WCLaV-1 (GenBank accession nos. MW559074-82) shared 100% nt/aa identities with each other and with corresponding sequences of WCLaV-1 isolate KF-1 from China (KY781184-86). The partial RNA1-RNA3 sequences of WCLaV-2 (MW559083-91) shared 97-100% nt/96-100% aa identities with each other and with corresponding sequences of WCLaV-2 isolate KF-15 from China (KY781187-89). This is the first report of WCLaV-1 and WCLaV-2 in Texas and the first record of both viruses in the U.S. and elsewhere outside of China. Both negative-sense, single-stranded RNA viruses represent a novel taxon in the family Phenuiviridae (order Bunyavirales) (Xin et al. 2017). While aspects of the biology of both viruses are yet to be elucidated, our results expand their geographical range. The detection primers developed here will be useful for screening cucurbits germplasm to avert their spread.

New method for observing, demonstrating, and teaching additive color mixture

AbstractThe trichromatic principles of additive and subtractive color mixture have been the foundation of the color reproduction technologies for about 130 years. Yet, today, they remain a poorly understood phenomenon in much of the fine art world as well as the general public. Part of the problem stems from a lack of a simple, effective, widely accessible method for presenting additive color mixtures. This article describes a new, unique means of demonstrating additive color mixture using colored mosaic patterns displayed on computer screens in combination with a simple optical diffuser. Three illustrations composed of primary colored mosaic designs are described along with the underlying theory they are based upon. The potential for this technique as a valuable educational tool for teaching the art and science of color mixture, as well as a new approach for designs in the visual arts, is discussed. Finally, a small representational luminous mosaic image is offered as an example of the creative possibilities in this unexplored realm of art.

Reprogramming of DNA methylation is linked to successful human preimplantation development

Human preimplantation development is characterized by low developmental rates that are poorly understood. Early mammalian embryogenesis is characterized by a major phase of epigenetic reprogramming, which involves global DNA methylation changes and activity of TET enzymes; the importance of DNA methylation reprogramming for successful human preimplantation development has not been investigated. Here, we analyzed early human embryos for dynamic changes in 5-methylcytosine and its oxidized derivatives generated by TET enzymes. We observed that 5-methylcytosine and 5-hydroxymethylcytosine show similar, albeit less pronounced, asymmetry between the parental pronuclei of human zygotes relative to mouse zygotes. Notably, we detected low levels of 5-formylcytosine and 5-carboxylcytosine, with no apparent difference in maternal or paternal pronuclei of human zygotes. Analysis of later human preimplantation stages revealed a mosaic pattern of DNA 5C modifications similar to those of the mouse and other mammals. Strikingly, using noninvasive time-lapse imaging and well-defined cell cycle parameters, we analyzed normally and abnormally developing human four-cell embryos for global reprogramming of DNA methylation and detected lower 5-methylcytosine and 5-hydroxymethylcytosine levels in normal embryos compared to abnormal embryos. In conclusion, our results suggest that DNA methylation reprogramming is conserved in humans, with human-specific dynamics and extent. Furthermore, abnormalities in the four-cell-specific DNA methylome in early human embryogenesis are associated with abnormal development, highlighting an essential role of epigenetic reprogramming for successful human embryogenesis. Further research should identify the underlying genomic regions and cause of abnormal DNA methylation reprogramming in early human embryos.

Subtyping Cryptosporidium xiaoi, a Common Pathogen in Sheep and Goats.

Cryptosporidiosis is a significant cause of diarrhea in sheep and goats. Among the over 40 established species of Cryptosporidium, Cryptosporidium xiaoi is one of the dominant species infecting ovine and caprine animals. The lack of subtyping tools makes it impossible to examine the transmission of this pathogen. In the present study, we identified and characterized the 60-kDa glycoprotein (gp60) gene by sequencing the genome of C. xiaoi. The GP60 protein of C. xiaoi had a signal peptide, a furin cleavage site of RSRR, a glycosylphosphatidylinositol anchor, and over 100 O-glycosylation sites. Based on the gp60 sequence, a subtyping tool was developed and used in characterizing C. xiaoi in 355 positive samples from sheep and goats in China. A high sequence heterogeneity was observed in the gp60 gene, with 94 sequence types in 12 subtype families, namely XXIIIa to XXIIIl. Co-infections with multiple subtypes were common in these animals, suggesting that genetic recombination might be responsible for the high diversity within C. xiaoi. This was supported by the mosaic sequence patterns among the subtype families. In addition, a potential host adaptation was identified within this species, reflected by the exclusive occurrence of XXIIIa, XXIIIc, XXIIIg, and XXIIIj in goats. This subtyping tool should be useful in studies of the genetic diversity and transmission dynamics of C. xiaoi.

Mitochondrial DNA disorders: from pathogenic variants to preventing transmission.

Mitochondrial DNA (mtDNA) disorders are recognized as one of the most common causes of inherited metabolic disorders. The mitochondrial genome occurs in multiple copies resulting in both homoplasmic and heteroplasmic pathogenic mtDNA variants. A biochemical defect arises when the pathogenic variant level reaches a threshold, which differs between variants. Moreover, variants can segregate, clonally expand, or be lost from cellular populations resulting in a dynamic and tissue-specific mosaic pattern of oxidative deficiency. MtDNA is maternally inherited but transmission patterns of heteroplasmic pathogenic variants are complex. During oogenesis, a mitochondrial bottleneck results in offspring with widely differing variant levels to their mother, whilst highly deleterious variants, such as deletions, are not transmitted. Complemented by a complex interplay between mitochondrial and nuclear genomes, these peculiar genetics produce marked phenotypic variation, posing challenges to the diagnosis and clinical management of patients. Novel therapeutic compounds and several genetic therapies are currently under investigation, but proven disease-modifying therapies remain elusive. Women who carry pathogenic mtDNA variants require bespoke genetic counselling to determine their reproductive options. Recent advances in in vitro fertilization techniques, have greatly improved reproductive choices, but are not without their challenges. Since the first pathogenic mtDNA variants were identified over 30 years ago, there has been remarkable progress in our understanding of these diseases. However, many questions remain unanswered and future studies are required to investigate the mechanisms of disease progression and to identify new disease-specific therapeutic targets.

Leprous Neuropathy: Observational Study Highlighting the Role of Electrophysiology in Early Diagnosis.

Background Worldwide leprosy is a common cause of peripheral neuropathy. Electrophysiology is underutilized in its diagnosis. Objective This study aims to evaluate the usefulness of electrophysiological study in the diagnosis of leprous neuropathy. Materials and Methods Clinical and electrophysiological abnormalities of 36 histopathology proven leprosy patients from January 2015 to January 2017 were studied. Statistical Analysis Proportions were compared by Chi-square test. Results Total patients were 36. Thirty-four patients had abnormal electrophysiology and 34 had neurological deficits like weakness, sensory changes, and thickening. By clinical examination, multiple nerve involvement (motor weakness, sensory changes, and nerve thickening) occurred in 29, single nerve in 5, and no nerve involvement in 2. With electrophysiology, multiple nerve involvement (mononeuritis multiplex) was present in 32, single nerve in 2, and normal conduction parameters in 2. From the 36 patients, a total of 1,008 nerves were subjected to clinical examination and 132 were picked up clinically as affected, (13.1%). Electrophysiological study was done in 504 nerves, and 215 were found to be involved, (43%). Nerve abnormality detected by electrophysiology is significantly higher than clinical detection. (Chi-square =164.4054; p = 0.0000). Clinically, the most commonly affected nerve was unar (27) and the least affected was median (2) nerve. Electrophysiology detected 69% of nerves with demyelination and 35% of nerves with axonal features (mosaic pattern). Discussion There was subclinical neuropathy with electroclinical dissociation, as evidenced by more abnormality in electrophysiology than clinical examination. The nerve involvement was mononeuritis or mononeuritis multiplex pattern, both clinically and electrophysiologically. Electrophysiology showed both axonal and demyelinating nerve involvement (mosaic pattern). All the three features are present in leprous neuropathy. In corollary, if a patient has these electrophysiological features, he should be thoroughly investigated for leprosy. Conclusion Triple findings, such as subclinical neuropathy with electroclinical dissociation, mononeuritis multiplex, and mosaic pattern of demyelination and axonopathy, suggest leprous neuropathy

Complete genome sequences of anemone mosaic virus and ranunculus mild mosaic virus isolated from anemone imported from the Netherlands into Japan.

Anemone mosaic virus (AnMV) and ranunculus mild mosaic virus (RanMMV) infect anemone plants, which exhibit characteristic mosaic patterns on their leaves. Employing next-generation sequencing of plant material imported from the Netherlands, the complete genome sequences of these two viruses were determined for the first time. AnMV and RanMMV have 9698 and 9537 nucleotides (nt), respectively, excluding the poly(A) tail. They share 80.0%/82.0% and 98.0%/97.0% nt/amino acid (aa) sequence identity, which is above the species demarcation value, in the previously reported AnMV and RanMMV coat protein sequences, but they share 69.0%/70.0% nt/aa sequence identity or less with other potyviruses in all 10 mature protein coding regions of the genome. Additionally, phylogenetic analysis confirmed the relationship of the AnMV and RanMMV genome sequences to previously reported partial sequences and placed them within the genus Potyvirus. These results show that these two viruses represent separate species within the genus Potyvirus.

A De Novo Mosaic PHEX Variant Causing Sporadic X-Linked Hypophosphatemic Rickets in a 2-Year-Old Girl.

Pathogenic variants in the PHEX gene are causative of X-linked hypophosphatemic rickets (XLH). We present a case of a 2-year-old girl with hypophosphatemic rickets with genu varum and short stature without any family history of XLH. Next generation sequencing of the PHEX gene identified a splice donor variant, NM_000444.6:c.1173 + 5G > A in intron 10. This variant had a mosaic pattern with only 22% of the sequence reads showing the variant allele and was not present in the girl's parents, both of whom had a normal phenotype. This is a sporadic case of a de novo mosaic splice-site variant in the PHEX gene.

Histochemical Distribution of Acetylcholinesterase in the Forebrain Nuclei of an Indian Non Catfish Channa punctatus

Background: Acetylcholinesterase (AChE) is an enzyme belonging to hydrolase group which splits the acetylcholine in to choline and acetate. It is supposed to be a marker of cholinergic and cholinoceptive neurons. Acetylcholinesterase histochemisry has been done in a number of vertebrates but it is still obscure and scattered in fishes, particularly in Indian fishes. Methods: In the present study a modified histochemical technique has been employed to histochemically map the acetylcholinesterase containing neurons in the telencephalic and diencephalic nuclei of C. punctatus described by Hedreen, et al (1985).Result: Acetylchoinesterase is differentially expressed in the various prosencephalic centres and nuclei of the brain, thus its staining clearly demarcates these centres and nuclei based on varying enzyme intensity. Among the pallial nuclei of the forebrain, medial and dorsolateral nuclei showed intense enzyme activity while ventral dorsolateral nucleus and central nucleus showed moderate reaction. In contrast, most of the subpallial nuclei of the forebrain showed high intensity. Diencephalic nuclei of the forebrain exhibited mosaic pattern of enzyme distribution.

Electromechanical Manipulation of Topological Defects to Yield Giant Piezoelectric Response in Epitaxial Lead Zirconate Titanate Bilayers on Silicon

AbstractThe combination of topological defect mobility and exploitation of the boundary conditions in bilayer heterostructures presents an enormous opportunity for enhancing actuation responses from modest external stimuli in electromechanical applications. Tetragonal PbZr0.3Ti0.7O3 and underlying rhombohedral PbZr0.54Ti0.46O3 ferroelectric bilayers are epitaxially grown on silicon substrates. The topmost layer shows crystallographic symmetry lower than a typical tetragonal structure but is arranged in‐plane with a mosaic pattern of superdomains and ferroelastic a1/a2 nanodomains within. The domain pattern also shows a series of vortex/anti‐vortex pairs induced in the pseudo‐tetragonal film, which can be manipulated to either migrate across the film or annihilate one another in the presence of an external electrical bias. The mobility of defect pairs and domain walls, through reduced substrate clamping by the underlying rhombohedral film, is the driving force for endowing the bilayer with a ≈45% increased effective d33 response compared to a rhombohedral single layer on silicon. Furthermore, a square in‐plane polarization loop (≈32 µC cm–2) provides further evidence of the mobility and large‐scale polarization switching. An improvement of this magnitude demonstrates the opportunity to implement bilayer technology while exploiting a functional silicon substrate for enhanced, industry‐ready, smart material applications.

Metamaterial honeycomb with sign-toggling expansion coefficients that manifests an Islamic mosaic pattern at the Alhambra Palace

Metamaterial honeycomb with sign-toggling expansion coefficients that manifests an Islamic mosaic pattern at the Alhambra Palace

Familial juvenile onset Alexander Disease demonstrating germline mosaicism and presenting with a tumor-like mass of the medulla

Alexander Disease (AD) is a rare and ultimately lethal leukodystrophy, typically presenting in infants who exhibit developmental delay, macrocephaly, seizures, spasticity and quadriparesis. Classic infantile forms are generally due to sporadic mutations in GFAP that result in the massive deposition of intra-astrocytic Rosenthal fibres, particularly in the frontal white matter. However, phenotypic manifestations are broad and include both juvenile and adult forms that often display infratentorial pathology and a paucity of leukodystrophic features. We describe the unique case of an 8.5 year old female who presented with an 8 month history of progressively worsening vomiting and cachexia, whose extensive multidisciplinary systemic workup, including GI biopsies, proved negative. Neuroimaging ultimately revealed bilaterally symmetric and anterior predominant supratentorial signal alterations in the white matter plus a 1.7 x 1.2 x 0.7 mm right dorsal medullary mass. Biopsy of this presumed low-grade glioma revealed features in keeping with AD, which was later confirmed on whole exome sequencing. The proband exhibited a pathogenic p.Arg239Cys heterozygous missense mutation in GFAP, which was apparently inherited from her asymptomatic mother (1% mosaicism in the mother’s blood). Germline mosaic inheritance patterns of young-onset AD, particularly those presenting with a tumor-like mass of the brainstem, are scarcely reported in the literature and serve to expand the clinicopathologic spectrum of AD.LEARNING OBJECTIVESThis presentation with enable the learner to: 1.Recognize an uncommon clinical presentation of AD.2.Describe the underlying genetics of AD, including a rare familial juvenile onset form featuring germline mosaicism.

Pathologically and Genetically Diagnosed Subclinical Symptomatic Duchenne Muscular Dystrophy Carrier: Broadened Spectrum of Clinical Phenotype

A 29-year-old female presented with an elevated level of serum creatine kinase without subjective weakness. Neurologic examination showed the subtle motor weakness of the right arm. Muscle biopsy showed dystrophic changes and a mosaic pattern of dystrophin expression. The diagnosis was confirmed by multiplex ligation-dependent probe amplification and whole-exome sequencing, revealing heterozygous deletion of exon 44 in the DMD gene. Here, we introduce a subclinical symptomatic Duchenne muscular dystrophy carrier, which broadens the clinical spectrum of phenotype.

Processes underlying complex patterns of song trait evolution in a Setophaga hybrid zone.

During secondary contact between two species when hybrids are less fit than parents, mating signals are expected to diverge, while aggressive signals are expected to converge. If a single signal trait is used in both mating and aggression, then the dynamics between these two forces could influence the evolutionary trajectory of that trait. We studied such a situation in an avian hybrid zone between two Setophaga species, where birdsong is used in both mate attraction and territory defense. We hypothesized that song modules of the two species will show separate and distinct geographic patterns due to the influence of selective pressures for effective territorial aggression and for effective mate attraction. We conducted geographic cline analyses and playback experiments across this hybrid zone. We found an unexpected geographic pattern of asymmetric introgression of song rhythm, which may be explained by results of the playback experiments that suggest that differences in song rhythm serve a greater role in mate attraction than in territory defense. In contrast, differences in syllable morphology show little evidence of importance in mate attraction or territorial defense. Song features converge in the hybrid zone, yet patterns of trait change suggest that the song production modules may vary in their modes of development and inheritance. Syringeal motor gesturing, which gives rise to syllable morphology, shows a nonclinal mosaic pattern, suggesting that this trait may be predominantly learned. In contrast, respiratory patterning, which forms song rhythm, shows a clinal geographic transition, suggesting that this trait could be more innate. The results indicate that opposing forces act independently on song via distinct modules of the song production mechanism, driving complex patterns of song trait evolution.

Fibroblastic reticular cell lineage convergence in Peyer’s patches governs intestinal immunity

Abstract Fibroblastic reticular cells (FRCs) determine the organization of lymphoid organs and control immune cell interactions. While the cellular and molecular mechanisms underlying of FRC differentiation in lymph nodes and the splenic white pulp have been elaborated to some extent, in Peyer’s patches (PPs) they remain elusive. Using a combination of single-cell transcriptomics and cell fate-mapping in advanced mouse models, we found that PP formation in the mouse embryo is initiated by an expansion of perivascular FRC precursors, followed by FRC differentiation from subepithelial progenitors. Single-cell transcriptomics and cell fate-mapping confirmed the convergence of perivascular and subepithelial FRC lineages. Furthermore, lineage-specific loss and gain-of-function approaches revealed that the two FRC lineages synergistically direct PP organization, maintain intestinal microbiome homeostasis and control anti-coronavirus immune responses in the gut. Collectively, this study reveals a distinct mosaic patterning program that generates key stromal cell infrastructures for the control of intestinal immunity.

Blood supply of the anal canal in patients with chronic hemorrhoids

The most important factors in the development of chronic haemorrhoids today are considered to be the combination of two factors (vascular and mechanical) that lead to the development of hemorrhoids. The underlying vascular factor is the vascular dysfunction, providing arterial blood flow through the arteries to the cavernous bodies and outflow through the cavernous veins, which leads to dilation of cavernous bodies and the formation of vascular malformations.There were performed clinical examination and treatment of 140 patients with chronic hemorrhoids of stage III-IV according to Goligher. The features of arterial blood supply of the anal canal were evaluated by transrectal ultrasound examination.It was found that there was no clear linear relationship between the number of anal arteries with increased blood flow and the number of hemorrhoidal nodes in the patient. Each node was supplied with blood from one or two arteries: the node placed at 11 o'clock had blood supply from the arteries visualized at 10 and 11 o'clock, the node at 3 o'clock - arteries at 3 and 5 o'clock, the node at 7 o'clock - arteries at 7 and 9 o'clock. The arteries were most frequently visualized at the first (89.4%), the third (93.3%), the seventh (88.8%) and the eleventh (93.4%) hours. With less frequency the hemodynamically significant arteries were visualized at the fifth (65.0%), the ninth (62.8%) and the tenth (66.7%) hours. The arteries that were suppliing blood hemorrhoidal vessels were located in the internal sphincter at a depth of 5 to 10 mm. In the area of 3, 7 and 11 hours, they overlapped with a mosaic pattern that corresponded to the localization of the cavernous body and resembled an arteriovenous fistula according to the СDS.

Proteus Syndrome: A Rare Case in An Adult Ward.

Proteus syndrome is an extremely rare disorder that manifests as an asymmetric, disproportionate overgrowth of any connective tissue.The diagnosis can be difficult because the phenotypes are variable.It is important to keep in mind the importance of anticoagulation because patients are at risk of developing deep vein thrombosis and pulmonary embolism.

Morphology, vocalizations, and mitochondrial DNA suggest that the Graceful Prinia is two species

Abstract Prinias (Cisticolidae: Prinia) are resident warblers of open areas across Africa and Asia and include many polytypic species whose species limits have not been seriously reevaluated recently. Based on an integrative taxonomic analysis of morphology, song, and mitochondrial DNA (mtDNA), we suggest that 2 species should be recognized in the Graceful Prinia (Prinia gracilis) complex. In addition, our morphological analyses show the existence of a well-marked undescribed form in southeastern Somalia, which we name herein as a new subspecies. Prinia gracilis is a small, drab, long-tailed species with streaking above and plain pale underparts that has been suggested to fall into 2 groups: the southwestern nominate group (from Egypt to Oman) and the northeastern lepida group (from Turkey through India). However, the characters presented to justify this grouping are variable and show a mosaic pattern, and whether genetic and vocal differences exist is unknown. We found consistent between-group song differences, with the nominate group giving consistently longer inter-phrase intervals, whereas the members of the lepida group sing an essentially continuous reel. An mtDNA tree suggests a deep split between the nominate and lepida groups, with a coalescence time between these clades of ~ 2.2 million years ago. Vocal and mtDNA analyses provided evidence that the northeastern Arabian Peninsula taxon carpenteri belongs to the lepida group. We found that, of all the morphological characters proposed, only proportions and tail barring and spotting relatively consistently distinguish the 2 groups. However, these characters strongly suggest that the eastern Arabian Peninsula is populated by taxa of both the gracilis and lepida groups, in different areas, but we lack genetic and bioacoustic data to corroborate this. Although further study is needed in potential contact zones, we suggest that 2 species should be recognized in the P. gracilis complex, and we propose the retention of the English name Graceful Prinia for P. gracilis sensu stricto, while we suggest that P. lepida be known as Delicate Prinia.

Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies.

Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.

Effect of vegetation mosaic on spatial heterogeneity of soil organic carbon mineralization and nitrification in an alpine meadow

Patchy distribution of herbaceous species is common in degraded grasslands on the Qinghai-Tibetan Plateau, but the effects of such a mosaic pattern on soil biochemical properties have rarely been studied. We compared soil organic carbon (SOC) mineralization, nitrogen (N) availability, ammonia oxidation and plant N uptake between the following vegetation patch types (plant communities) in an alpine meadow: grass (dominated by Elymus nutans, Poa crymophila and Leymus secalinus), sedge (Kobresia capillifolia and Kobresia humilis), Polygonum viviparum (P. viviparum only), Artemisia smithii (A. smithii only) and Oxytropis kansuensis (O. kansuensis only). All patches had a diameter ranging from about tens of centimeters to several meters. SOC mineralization was faster in patches beneath grass or A. smithii than in those beneath sedge or O. kansuensis, but the faster SOC mineralization beneath grass and A. smithii patches did not result in a difference in SOC storage in the top 30 cm of soil compared with that in other patches. Greater litter production beneath grasses or belowground carbon input (largest root/shoot ratio) beneath A. smithii may have offset the negative effect of rapid SOC mineralization on SOC storage under grass and A. smithii patches. Productive grasses were associated with the highest level of N availability in the soil, consistent with their greater demands for N uptake. Sedge species and A. smithii inhibited nitrification by decreasing the abundance of ammonia oxidation bacteria in soil, in contrast to grasses. The inhibition of biological nitrification under A. smithii explained the finding that the soil beneath this vegetation patch type had the lowest nitrate content as a percentage of total inorganic N. However, the inhibition of nitrification beneath sedges did not induce a decrease in the nitrate content as a percentage of total inorganic N under sedge patches compared with that under grass patches. This suggests that sedges preferentially use ammonium instead of nitrate as their N source. It is concluded that patchy distribution of herbaceous species in alpine meadows created significant spatial heterogeneity in soil biological and biochemical properties at the field scale. Sampling in ecosystem studies clearly needs to take into account such heterogeneity of soil properties and processes in grasslands with patchily distributed vegetation.