Multiple NOR Research Articles

CRISPRi-based circuits to control gene expression in plants.

The construction of synthetic gene circuits in plants has been limited by a lack of orthogonal and modular parts. Here, we implement a CRISPR (clustered regularly interspaced short palindromic repeats) interference (CRISPRi)-based reversible gene circuit platform in plants. We create a toolkit of engineered repressible promoters of different strengths and construct NOT and NOR gates in Arabidopsis thaliana protoplasts. We determine the optimal processing system to express single guide RNAs from RNA Pol II promoters to introduce NOR gate programmability for interfacing with host regulatory sequences. The performance of a NOR gate in stably transformed Arabidopsis plants demonstrates the system's programmability and reversibility in a complex multicellular organism. Furthermore, cross-species activity of CRISPRi-based logic gates is shown in Physcomitrium patens, Triticum aestivum and Brassica napus protoplasts. Layering multiple NOR gates together creates OR, NIMPLY and AND logic functions, highlighting the modularity of our system. Our CRISPRi circuits are orthogonal, compact, reversible, programmable and modular and provide a platform for sophisticated spatiotemporal control of gene expression in plants.

Design of Laser-Powered Opto-Electrical Current Transformer and Its Application in Electrical Automation of Substations

The novel power equipment represented by the Opto-Electrical Current Transformer (OECT) possesses unparalleled advantages compared to traditional Current Transformers (CTs), rendering it with vast potential in power systems. In the design of OECT, this study employs laser power supply and focuses on the overall perspective, particularly the design of the laser power supply module and the optical fiber digital transmission module. The laser power supply module selects a high-power semiconductor laser to provide power to the circuit, incorporating line filters, thermistor resistors, and a laser overcurrent protection circuit. An automatic temperature control circuit based on PI regulation is utilized to stabilize the working temperature of the laser diode (LD). The photoelectric conversion device PPC-6E achieves a maximum photoelectric conversion efficiency of 40%, and the MAX639 DC–DC conversion chip ensures stable output voltage. The optical fiber digital transmission module adopts a circuit composed of multiple NOR gate logic for electro-optical conversion, a low-power driving circuit based on the 74LVC1G07 chip, and the HFBR-2412 photoelectric converter to simplify the circuit board design. To achieve a higher communication baud rate, a quartz multimode optical fiber with a diameter of 62.5 μm is chosen. In the experimental phase, a simulation of high-power AC power with equal turns is conducted. The linearity/temperature test results demonstrate that the designed OECT in this study meets expectations. In the electrical automation test of substations, a comparison between traditional CTs and the designed OECT is carried out using traditional protection algorithms and optical differential protection algorithms. The results indicate that, compared to traditional protection algorithms, the optical differential algorithm using the designed OECT achieves faster protection times.

Reconfigurable Skyrmion-Based Logic Gates: Versatile Design and Full-Scale Implementation.

Herein, we investigate the behavior of skyrmions within a racetrack design incorporating voltage-controlled magnetic anisotropy (VCMA) gates. Our analysis encompassed multiple forces, including spin currents and anisotropy gradients induced by bias voltages. As a result, the efficient control of skyrmion dynamics was achieved across various VCMA gate configurations. Building upon these findings, we propose an efficient approach to reconfigurable skyrmion logic (RSL) in a thin antiferromagnetic (AFM) film through a versatile design. Our RSL harnesses the selective integration of VCMA, spin-polarized currents, and skyrmion-skyrmion (sky-sky) interactions to implement multiple logic gates, including AND, OR, XOR, NOT, NAND, XNOR, and NOR. The design brings a significant advantage with its simplified fabrication process, making the implementation of the RSL practical and accessible for various applications. Furthermore, the RSL enables seamless dynamic switching between logic gates, thereby enhancing its multifunctionality. Additionally, the strategic incorporation of sky-sky interactions and skyrmion-edge repulsion prominently facilitates the realization of complex gates, such as NAND, XNOR, and NOR gates, that typically require intricate design efforts. Hence, this streamlined integration of RSL, coupled with its adaptability to changing computational needs, underscores its potential as a practical solution for implementing high-functionality skyrmion-based logic gates.

Allozyme and cytogenetic analysis in two species of Hypostomus (Siluriformes: Loricariidae) from the Paraguai River basin, Brazil: occurrence of B microchromosome and intrapopulation heterochromatic polymorphism in H. boulengeri

Abstract Hypostomus is distributed by Central and South America basins, with diverse species with taxonomic conflicts. This way, the integration of auxiliary techniques contributes to understanding the systematics and phylogeny of the group. Thus, this study aimed to investigate the Hypostomus cochliodon and H. boulengeri from the Onça stream (Paraguai River basin) by allozyme and cytogenetic techniques. Hypostomus boulengeri showed a diploid number of 68 chromosomes (14m+14sm+18st+22a), multiple NOR revealed by Ag-NOR and 18S rDNA FISH, a polymorphism of heterochromatin in acrocentrics and the presence of B microchromosome. Hypostomus cochliodon showed a diploid number of 64 chromosomes (16m+26sm+14st+8a); despite the single NOR, some individuals showed NOR in both telomeres detected by Ag-NOR and 18S rDNA FISH. Isozyme identified two diagnostic loci (Idh-A and Gdh-A) between the two species and multiple loci with unique alleles in H. boulengeri. The genetic variability indicated by the mean heterozygosity (He) was 0.2461 and 0.0309 in H. boulengeri and H. cochliodon,respectively.Thus, this study reports the first cytogenetic data for H. boulengeri and the first isozymatic data for H. boulengeri and H. cochliodon. The two species presented evident cytogenetic and isoenzymatic differences with the obtaining of exclusive genetic markers providing support for future evolutionary studies in the group.

Karyological Diversification in the Genus Lyciasalamandra (Urodela: Salamandridae).

Simple SummaryThe Lycian salamanders of the genus Lyciasalamandra are characterized by a debated taxonomy and phylogenetic relationships. They have been the subject of various molecular and phylogenetic analyses, but their chromosomal diversity is completely unknown. We here present a comparative cytogenetic analysis on five out of the seven described species and seven subspecies of Lyciasalamandra, providing the first karyological assessment on the genus and comparing them to closely related representatives of the genus Salamandra. We analyzed the occurrence and distribution of different conserved (chromosome number and morphology) and highly variable karyological features. We found an impressive diversity in the configuration of nucleolus organizing regions (NORs), which alternatively occur either as heteromorphic or homomorphic loci on distinct regions of different chromosome pairs. We highlight that the observed peculiar taxon-specific pattern of chromosome markers supports the taxonomic validity of the different studied evolutionary lineages and is consistent with a scenario of synchronous evolution in the Lycian salamanders.We performed the first cytogenetic analysis on five out of the seven species of the genus Lyciasalamandra, including seven subspecies, and representatives of its sister genus Salamandra. All the studied species have a similar karyotype of 2n = 24, mostly composed of biarmed elements. C-bands were observed on all chromosomes, at centromeric, telomeric and interstitial position. We found a peculiar taxon-specific NOR configuration, including either heteromorphic and homomorphic NORs on distinct regions of different chromosomes. Lyciasalamandra a. antalyana and L. helverseni showed two homomorphic NORs (pairs 8 and 2, respectively), while heteromorphic NORs were found in L. billae (pairs 6, 12), L. flavimembris (pairs 2, 12), L. l. luschani (pairs 2, 12), L. l. basoglui (pairs 6, 12), L. l. finikensis (pairs 2, 6) and S. lanzai (pairs 8, 10). Homomorphic NORs with an additional supernumerary site were shown by S. s. salamandra (pairs 2, 8) and S. s. gigliolii (pairs 2, 10). This unexpected highly variable NOR configuration is probably derived from multiple independent NOR translocations and paracentric inversions and correlated to lineage divergence in Lyciasalamandra. These results support the taxonomic validity of the studied taxa and are consistent with a hypothesized scenario of synchronous evolution in the genus.

A DNA based molecular logic gate capable of a variety of logical operations

In this paper we report on a module in the RTRACS (Reverse-transcription and TRanscription-based Autonomous Computing System) molecular computing system, constructed with DNA, RNA and enzymes. The module is a 2-input logic gate that receives input and produces output in the form of RNA molecules. Each of the two input molecules is chosen from a set of two, and the logic gate produces an output molecule for each of the four possible input combinations. Two output RNA molecules can be produced by this module, one for only one combination of inputs, whilst the remaining three combinations lead to the production of the other output. Since the RNA strands can be arbitrarily assigned logical values, this module is capable performing multiple logical operations, including AND, NAND, OR and NOR, given the appropriate mapping of RNA molecules to logical values. We performed numerical simulations of the logic gate reaction scheme, revealing the details of the kinetics of the production of output molecules and the theoretical input---output characteristics. We experimentally demonstrated the proper functioning of the logic gate and the real time production of output molecules. Furthermore, we demonstrate an implementation of the logic gate in diagnosing single nucleotide polymorphism patterns on samples of human genomic DNA. We believe this versatile logic gate has significant advantages as a basic module of RTRACS due to the wide variety of possible logical operations.

First record of supernumerary (B) chromosomes in electric fish (Gymnotiformes) and the karyotype structure of three species of the same order from the upper Paraná River basin

Cytogenetic studies were performed on the species Apteronotus prope albifrons Linnaeus, 1766, Rhamphichthys hahni Meinken, 1937 and Brachyhypopomus gauderio Giora & Malabarba, 2009, collected in the upper Paraná River floodplain, Porto Rico (PR), Brazil. Apteronotus prope albifrons showed a diploid number of 2n=24 chromosomes for both sexes and a karyotype formula of 14m+2sm+2st+6a (FN=42). Besides the standard karyotype, three specimens had one to three extra microchromosomes with inter- and intra-individual variations, which suggested the occurrence of B chromosomes in the species. The chromosomal data of Rhamphichthys hahni, described here for the first time, consists of 50 chromosomes and a formula comprised of 20m+24sm+6a (FN=94). Brachyhypopomus gauderio specimens demonstrated 2n=42 chromosomes infemales, all acrocentric, and 2n=41 chromosomes in males, with 40 acrocentric and 1 medium-sized metacentric chromosome. These differences concern with a multiple system of sexchromosome determination X1X1X2X2/X1X2Y (FN=42) in Brachyhypopomus gauderio. The analysis of nucleolar organizer regions by Ag-NOR and FISH 18S banding revealed a simple NOR system in Apteronotus prope albifrons and Rhamphichthys hahni and a multiple NOR system in Brachyhypopomus gauderio, that is unusual for Gymnotiformes fishes. Constitutive heterochromatin was mainly found in the pericentromere region in most of the chromosomes of the three species, although each species had its own peculiarities. The B chromosomes in Apteronotus prope albifrons demonstrated heterochromatin positioned in the centromeric and telomeric regions whereas Rhamphichthys hahni presented conspicuous blocks of heterochromatin on the long arms in three submetacentric pairs. Brachyhypopomus gauderio showed blocks of heterochromatin on the long arm in the interstitial and telomere positions. The finding of B chromosomes in Apteronotus prope albifrons represents the first description of these elements in the Gymnotiformes order. Although the karyotype of this species is similar with that described for populations in the Amazon basin, the presence of B chromosomes could represent a specific characteristic of this population. A comparative analysis of karyotypes of Rhamphichthys hahni with other species of the genus showed a relatively conservative structure suggesting 2n=50 as a common number in this group. The karyotype of Brachyhypopomus gauderio, a new species, provides an important reference for future chromosome studies of the Brachyhypopmus Mago-Lecia, 1994, and it might be also significant for cytotaxonomy in this group. The cytogenetic data also demonstrate the need of more comparative cytogenetic studies in the families of the highly diversified and taxonomically difficult complex Gymnotiformes.

Chromosome polymorphism in Rineloricaria pentamaculata (Loricariidae, Siluriformes) of the Paraná River basin

Cytogenetic analysis in three Rineloricaria pentamaculata populations revealed diploid number 2n = 56 chromosomes, karyotype formula 8m/sm + 48st/a and FN = 64. Owing to the presence of the heteromorphic chromosome pair with a big submetacentric chromosome and a small acrocentric one in both males and females, 42.9% of specimens in the Taua Stream population had the karyotype formula 9m/sm + 47st/a and FN = 65. Analysis of the nucleolus-organizing region by Ag-NOR and FISH techniques showed a single NOR system at pair 5 for R. pentamaculata populations of the Keller River and the Taua Stream. However, specimens of populations of the Tatupeba Stream had multiple NOR systems at pairs 5 and 8. A constitutive heterochromatin pattern in R. pentamaculata is mainly distributed in the pericentromeric and telomeric regions with interstitial markers in certain chromosomes. Heterochromatin is located in the telomeric and centromeric positions of the acrocentric chromosome in the heteromorphic pair of the Taua Stream population. In the submetacentric chromosome the markings are located in the telomeric (short arm), pericentomeric and interstitial (long arm) positions. The origins of polymorphisms are discussed.

Comparative cytogenetics of Carnegiella marthae and Carnegiella strigata (Characiformes, Gasteropelecidae) and description of a ZZ/ZW sex chromosome system

Comparative cytogenetic analyses of hatchetfishes Carnegiella marthae and Carnegiella strigata (Gasteropelecidae) from the Rio Negro basin were performed using conventional Giemsa staining, silver (Ag) -staining and C-banding. The diploid chromosome numbers of both species equaled 2n = 50 but their karyotypes were distinct. We found evidence for sex chromosomes in C. marthae since karyotype of males presented 20 M + 12 SM + 4 ST + 14 A and ZZ ST chromosomes while the females presented 20 M + 12 SM + 4 ST + 14 A and ZW ST chromosomes of distinct size. Conversely, C. strigata presented 4 M + 4 SM + 2 ST + 40 A chromosomes without sex chromosome heteromorphism. Karyotypes of both species had two NOR-bearing SM chromosomes of distinct size indicating the presence of multiple NOR phenotypes. The sex chromosome pair had specific C-banding pattern allowing identification of both Z and W. This heteromorphic system has previously been described for the gasteropelecids.

B chromosomes in a population of Astyanax eigenmanniorum (Characiformes, Characidae) from the Araguari River Basin (Uberlândia, MG, Brazil)

A cytogenetic study was conducted on an Astyanax eigenmanniorum population from the Caetano Stream (18° 44' 56 S/ 048° 18' 39 W) - in Uberlândia, MG, Brazil - showing a modal diploid number of 48 chromosomes in the standard male and female karyotypes. However, in several specimens it was also possible to observe metaphases with one or two B chromosomes, increasing the diploid number to 49 or 50 chromosomes, respectively. The supernumerary chromosomes were totally heterochromatic and highlighted after C-banding. The silver-stained nucleolus organizing regions (Ag-NORs) were located in at least five chromosomes of the standard karyotype, thus characterizing a multiple NOR system in the species. This is the first occurrence of an A. eigenmanniorum population with 2n = 48 chromosomes, bearing supernumerary chromosomes.

Karyotypic characterization of two species of the genusSerrapinnus(Characiformes, Characidae), with the description of a structural polymorphism inS. heterodon

The family Characidae, one of the largest and more diversified fish families in the Neotropical region, is certainly not a monophyletic group, which is supported by the cytogenetic data showing its extensive chromosome variability. In this work, two species of the genus Serrapinnus, S. heterodon and S. piaba, from the Sao Francisco river basin were analyzed. Both species presented the same diploid number, 2n=52 chromosomes, and the same karyotypic formula, 16m+20sm+14st+2a. The heterochromatin distribution, evidenced by C-banding, was also similar between both species. On the other hand, two NORs were evidenced in S. heterodon, while a multiple NOR system was characterized in S. piaba, both confirmed by silver nitrate staining as well as by fluorescent in situ hybridization with 18S rDNA probe. Furthermore, two additional karyotypes (cytotypes) were observed in S. het- erodon, with 15m+20sm+14st+3a and 17m+20sm+14st+1a chromosomes, respectively, characterizing a structural chromosome polymorphism in the population. The differences between the three S. heterodon karyotypic forms are probably due to pericentric inversions related to the 8 th and 26 th chromosome pairs.

Chromosomal location of 5S and 18S rRNA genes in three sympatric cytotypes ofAstyanax scabripinnis(Characiformes, Characidae) from the Ivaí river basin, state of Paraná, Brazil

Analyses of the distribution of rDNA genes (both 5S and 18S) using classical techniques, such as silver and CMA3 staining and FISH were carried out in specimens of Astyanax scabripinnis from Tatupeba stream (Ivaí river basin). The three cytotypes identified for this population presented multiple NOR system, with intra-populational numerical and positional variations, detected for Ag-NOR, CMA3 and 18S-FISH. In contrast, data obtained from rDNA-5S revealed a highly conserved chromosomal distribution pattern in each cytotype. Aspects on divergences among distribution pattern of sites 5S and 18S rDNA are discussed.

Polymorphism of major ribosomal gene chromosomal sites (NOR-phenotypes) in the hybridogenetic fish Squalius alburnoides complex (Cyprinidae) assessed through crossing experiments

Chromosomal locations of major ribosomal sites, i.e. NOR-phenotypes, were assigned in Squalius alburnoides complex using sequential chromomycin A3 (CMA3)- and silver (Ag)-staining. This hybridogenetic Iberian minnow comprises diploid, triploid and tetraploid forms that arose by interspecific hybridisation between S. pyrenaicus and an unknown species. Inheritance of NOR patterns was studied by means of crossing experiments involving most diploid-polyploid forms of the S. alburnoides complex with identified specific genotype constitution. In all the specimens studied, the NORs were localised in the short arms of submetacentric chromosomes. Although S. pyrenaicus presented only one pair of NOR-bearing chromosomes, the data from experimental crosses evidenced that S. alburnoides complex was characterised by a multiple NOR phenotype composed of one chromosome pair with stable NORs and two chromosome pairs with NOR site polymorphism of presence/absence type. These data suggest that the karyotype of the unknown parental species of the S. alburnoides complex should have a multiple NOR pattern and emphasised the role of the all-male diploid linage in the dynamics and evolutionary potential of the S. alburnoides complex allowing the preservation of the missing ancestor genome. Cross-analyses evidenced that in spite of the high polymorphic nature of NORs in this fish complex, we have no reason to reject the hypothesis that their inheritance patterns were in accordance with Mendelian segregation.

CMOS process independent propagation delay macromodelling

An accurate CMOS process independent propagation delay macromodel is presented for inverter and multiple input NAND and NOR gates. A new nonsymmetrical input dependent delay model is shown to improve delay estimation accuracy. CMOS process independence is achieved without the application of recurrent data fitting techniques.

Chromosome Analysis of 5 Species of the Cichlidae Family (Pisces-Perciformes) from the Parana River.

The five species analyzed presented the same diploid number, 2n=48 chromosomes, but differed in karyotype formula. These results agree with the proposition that cichlids present a more conservative karyotype evolution and that the most frequent rearrangements appear to have been pericentric inversions and/or deletions. Only Crenicichla lepidota presented a multiple NOR system, indicating that the condition of a single nucleolar organizer is more primitive in this group. We may also state that constitutive heterochromatin seems to be highly conservative, with a preferentially pericentromeric pattern and with C-band positive NORs.

A 5-32 bit decoder for application in a crossbar switch

A novel voltage state multiple input NOR gate has been designed and tested for use as the basic gate in a 5-32 b parallel-input decoder. Two versions of this NOR gate are presented, one with a single output and one with a selectable output. The combination of the two types of NOR gate makes it possible to construct a 5-32 b decoder with considerably less gate current than would be required if it were constructed in other logic families. Since only a single gate current is required by each NOR gate and because only 12 NOR gates are needed to build the full decoder, a clock with a peak current level of only 6 mA is sufficient to power all of the decoder's 72 constituent superconducting quantum interference devices (SQUIDs). The decoder also occupies a small area compared with other designs. The authors review critical design issues of the NOR gates, and present low-speed and high-speed results of subblocks of the full 5-32 b decoder. >

Cytogenetic Studies in North American Minnows (Cyprinidae). XXVI. Chromosomal NOR phenotypes of 21 species from the Western United States.

Karyotypes and chromosomal nucleolus organizer region or NOR phenotypes of 19 described and two undescribed species of western North American cyprinids are documented. All 21 species examined possessed 2N=50 chromosomes and at least two pair of NOR-bearing chromosomes. The high incidence of multiple NOR chromosomes among western cyprinids is unusual. One pair of A NOR chromosomes was found in all 21 species, and 17 species possessed a second pair of A NOR chromosomes. An AA NOR state was hypothesized to represent a chromosomal synapomorphy uniting western cyprinids (including the genus Richardsonius) into a monophyletic assemblage. Within this clade, a transition from an A NOR to a D NOR was hypothesized to represent a chromosomal synapomorphy uniting three speices of the subgenus Gila, and an addition of an F NOR was hypothesized to represent a chromosomal synapomorphy uniting two species of the genus Rhinichthys. Chromosomal NORs in western cyprinids appear conserved relative to eastern cyprinids and may be the result of (i) a process of karyotypic canalization, and/or (ii) character state reversal in, or introgressive hybridization among, western cyprinid genera.

Amplification of ribosomal genes and formation of extrachromosomal nucleoli in oocytes of starfish Henricia hayashi (Asteroidea: Echinasteridae)

DNA and RNA specific dyes, Ag-NOR staining and in situ hybridization were used for studying the nucleolar apparatus in the growing oocytes of Henricia hayashi (Asteroidea: Echinasteridae). A plasmid containing ribosomal genes of Drosophila melanogaster (Kolchinsky et al., 1980) labelled with 3H by nick-translation served as an rDNA probe. Multiple extrachromosomal nucleoli are formed by the cascade type as a result of growth and subsequent fragmentation of the chromosomal (primary) rDNA body and its derivative extrachromosomal (secondary) rDNA bodies. Ribosomal genes were shown in all nucleolar structures. Argentophilia of the primary and secondary DNA bodies appears to be due to the dense packing of the rDNA-containing material. Ag (+) NORs were detected in the extrachromosomal multiple nucleoli and NOR complexes. Amplification of rDNA is a highly probable conclusion from the existing data.

Performance of Hardened P-MOS Devices in Severe Neutron Environments

P-channel MOS devices with a hardened gate insulator have been irradiated to a combined dose of 2 × 1016 n/cm2 (E>1.5 MeV) and 1 × 108 rads (Si). The resulting degradation in device characteristics is described and compared with that due to gamma radiation alone. Significant neutron-induced channel mobility degradation was observed, but the anticipated changes in source-drain punch-through voltage and body effect due to neutron-induced carrier removal were not observed until subsequent post-radiation annealing. After 1 × 1016 n/cm2 and 1 × 108 rads (Si), the test devices were still operational, with a 50% decrease in drain current and a 4V increase in threshold voltage. The extension of this technology to the fabrication of a 5 ampere power switch and a multiple NOR gate integrated circuit, both hardened to doses above 107 rads (Si), is also described.