56 research outputs found
MacWilliams extending conditions and quasi-Frobenius rings
Get PDF© 2022 Elsevier Inc. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Algebra. To access the final edited and published work see https://doi.org/10.1016/j.jalgebra.2022.05.005MacWilliams proved that every finite field has the extension property for Hamming weight which was later extended in a seminal work by Wood who characterized finite Frobenius rings as precisely those rings which satisfy the MacWilliams extension property. In this paper, the question of when is a MacWilliams ring quasi-Frobenius is addressed. It is proved that a right or left noetherian left 1-MacWilliams ring is quasi-Frobenius thus answering the different questions asked in [13], [22]. We also prove that a right perfect, left automorphism-invariant ring is left self-injective. In particular, this yields that if R is a right (or left) artinian, left automorphism-invariant ring, then R is quasi-Frobenius, thus answering a question asked in [13]
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Identification and Characterization of Cowpea Aphid Salivary Proteins and the Cowpea Resistance Mechanism to the Cowpea Aphid
Get PDFCowpea (Vigna unguiculata) is a vital crop for semiarid regions of the world. Cowpea is able to withstand harsh abiotic stresses prevalent in these regions but is susceptible to the cowpea aphid (Aphis craccivora). Unlike most aphids, cowpea aphids are phytotoxic and damage cowpea even at low populations. Aphids feed on plant phloem sap and while feeding deposit saliva which contain proteinaceous effectors to disrupt plant defenses and alter plant physiology. The composition of the cowpea aphid saliva has not been well studied and how cowpea aphids manipulate their hosts remain unresolved. While resistance to cowpea aphids has been identified in an African cowpea line, and the genetic determinants of the resistance mapped to two QTLs, the underlying resistance mechanisms remain unknown. In Chapter One, liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to identify the proteome of the cowpea aphid saliva. One of the proteins identified, diacetyl/L-xylulose reductase (DCXR), was functionally characterized using Agrobacterium-mediated transient expression and in vitro biochemical analyses. DCXR is a member of short-chain dehydrogenases/reductases invovled in both carbohydrate and dicarbonyl metabolism. I showed that cowpea aphid infestation transiently induces the cytotoxic dicarbonyl, methylglyoxal, in cowpea. Recombinant cowpea aphid DCXR (AcDCXR) was able to detoxify methylglyoxal in vitro and to oxidize the carbohydrate xylitol to xylulose and expression of AcDCXR in pea (Pisum sativum) improved aphid fecundity. Using resistant and susceptible cowpeas, and various aphid infestation approaches and behavioral assays, I determined the nature of the resistance in Chapters Two and Three. In Chapter Two, the susceptible interaction is elaborated and the resistance mechanism revealed to be localized in the phloem and to involve both antibiosis and antixenosis. In Chapter Three, aphid dispersal assays indicate aphids prefer susceptible cowpea to resistant. In addition, using timecourse infestation of resistant and susceptible cowpeas and RNASeq, I determined the genes regulated in both susceptible and resistant responses. The transcriptome analyses identified major differences in susceptible and resistant cowpea including involvement of multiple plant hormones and defense related genes. A subset of these genes are candidates for further exploration as the source of resistance
Projection-forcing multisets of weight changes
No full textAbstractLet F be a finite field. A multiset S of integers is projection-forcing if for every linear function ϕ:Fn→Fm whose multiset of weight changes is S, ϕ is a coordinate projection up to permutation and scaling of entries. The MacWilliams Extension Theorem from coding theory says that S={0,0,…,0} is projection-forcing. We give a (super-polynomial) algorithm to determine whether or not a given S is projection-forcing. We also give a condition that can be checked in polynomial time that implies that S is projection-forcing. This result is a generalization of the MacWilliams Extension Theorem and work by the first author
Additional file 1 of Transcriptome analysis of aphid-resistant and susceptible near isogenic lines reveals candidate resistance genes in cowpea (Vigna unguiculata)
No full textAdditional file 1: Figure S1. Damage induced by cowpea aphids after 7-days feeding on susceptible cowpea results in chlorosis and necrosis near feeding sites and leaf curling. Photos depict week-old plants infested with 15 adult apterous aphids. Figure S2. Growth of cowpea aphid population on susceptible (CB46) and resistant (CB77) cowpea. Two-week-old plants were infested with 20 adult apterous aphids on a single unifoliate leaf and enclosed in a mesh sleeve bag for 1 week. The aphid population was counted daily. Data from MacWilliams et al. 2022. Figure S3. Gene ontology (GO) analyses indicated numerous processes enriched in resistant and susceptible plants over time (day 6 vs day 1) that may play a role in constitutive resistance. Grey shading indicates processes uniquely expressed within each genotype. Figure S4. Gene ontology (GO) analyses indicated numerous processes are enriched when cowpea aphids feed on susceptible plants, with more processes upregulated than downregulated after correcting for leaf development. Resistant plants show enrichment in only 20% (6/30) of the total pathways enriched in susceptible plants when aphids feed. Figure S5. MDS plots for RNAseq show separation of time points. Overall, each treatment clusters together with the largest separation explained by time. Figure S6. qRT-PCR validation of select genes differentially expressed in RNAseq data relative to susceptible (CB46) uninfested plants. Genes consistently upregulated across time in resistant cowpea (CB77; A:RGA4-600, B:RGA4-700) and genes differentially expressed among treatments (C:CHiB, D:STE11) showed expression trends in concordance with RNAseq data (*) relative to susceptible control tissues at the collection time point. Primers for select genes are listed (E) and the fit of all expression data to count data showed high correlation (F: R2=0.79)
"The Appearance of Substance" : Examining in Tandem the Buddhist Teaching of No-Self and Poststructuralist Theories of Gender and Subject Formation
No full textx, 80 p.In this SIP, we have contemporary poststructuralist theories about identity formation on the one hand, and Zen Buddhist teachings of interdependent origination, emptiness, and no-self on the other. Reading and analyzing these both at once, there emerge a few common themes, such as the notion of identity as both something that is socially and culturally constructed and something that is always in-process, that is an activity rather than a substance, that is a "doing" rather than a "being." These perspectives are both very intentionally engaged in the deconstruction of identity, especially those types of identities that make themselves out to be the most concrete, fixed, and stable. Both of these perspectives approach identity in critical ways that have implications that are personally meaningful for the author and yet can be far-reaching. Work by Michel Foucault, Judith Butler, and Juana Maria Rodriguez are given close analysis
F9. Analysis of crash reconstruction program results
No full textGeneral Motors Corporation, Warren, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/1350/2/95104.0001.001.pd
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Cowpea aphid resistance in cowpea line CB77 functions primarily through antibiosis and eliminates phytotoxic symptoms of aphid feeding
Get PDFCowpea (Vigna unguiculata) is one of the most important crops in semiarid areas of the world, where it thrives in hot, dry conditions. While cowpea is able to withstand abiotic stresses, it suffers serious losses from biotic antagonists, including infestation by the cowpea aphid (Aphis craccivora). Cowpea aphid infestations are highly destructive, especially on young plants. However, it is unclear whether cowpea aphid damage is the result of aphids having phytotoxic effects on their hosts, or simple density effects. To better understand cowpea aphid damage and the potential for resistance traits to mitigate aphid impacts, we evaluated phenotypic changes in cowpea in response to variable aphid densities and systemic versus local infestations. Low aphid densities induced leaf distortions and pseudogalling, suggesting that cowpea aphids are phytotoxic to cowpea. Resistance to the cowpea aphid has been previously identified in an African cowpea germplasm, and near isogenic lines (NILs) containing resistance quantitative trait loci (QTL) were generated in the California blackeye cultivar background. Using a series of performance assays, we determined that resistance conferred by the two QTL counteracts aphid phytotoxicity and severely limits aphid growth and fecundity. Using choice assays, a preference by cowpea aphids for the susceptible NIL was observed. Electrical penetration graph analysis revealed that the resistance phenotype includes weak surface level deterrence and strong phloem-based resistance that manifests during the sap ingestion phase. Our study provides evidence of phytotoxic traits in A. craccivora while identifying a viable means of counteracting aphid damage and reproductive potential through resistance
Transcriptome analysis of aphid-resistant and susceptible near isogenic lines reveals candidate resistance genes in cowpea (Vigna unguiculata)
Get PDFBACKGROUND: Cowpea (Vigna unguiculata) is a crucial crop for regions of the world that are prone to both heat and drought; however, the phytotoxic cowpea aphid (Aphis craccivora) impairs plant physiology at low population levels. Both antibiotic and antixenotic forms of resistance to the aphid have been mapped to two quantitative trait loci (QTLs) and near isogenic lines (NILs). The molecular mechanism for this resistance response remains unknown. RESULTS: To understand the genes underlying susceptibility and resistance, two cowpea lines with shared heritage were infested along a time course and characterized for transcriptome variation. Aphids remodeled cowpea development and signaling relative to host plant resistance and the duration of feeding, with resource acquisition and mobilization determining, in part, susceptibility to aphid attack. Major differences between the susceptible and resistant cowpea were identified including two regions of interest housing the most genetic differences between the lines. Candidate genes enabling aphid resistance include both conventional resistance genes (e.g., leucine rich repeat protein kinases) as well as multiple novel genes with no known orthologues. CONCLUSIONS: Our results demonstrate that feeding by the cowpea aphid globally remodels the transcriptome of cowpea, but how this occurs depends on both the duration of feeding and host-plant resistance. Constitutive expression profiles of the resistant genotype link aphid resistance to a finely-tuned resource management strategy that ultimately reduces damage (e.g., chlorosis) and delays cell turnover, while impeding aphid performance. Thus, aphid resistance in cowpea is a complex, multigene response that involves crosstalk between primary and secondary metabolism. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12870-022-04021-w
A genetic analysis of bacteriophage lambda integrase-core site interactions
No full textBacteriophage lambda utilizes a site-specific recombination system to integrate its DNA into the E. coli chromosome during lysogeny. The viral protein, Integrase (Int), catalyzes strand exchange between the phage attachment site, attP, and the host target sequence, attB to generate the prophage sites, attL and attR. attP contains the core region, where strand exchange occurs, and the required flanking sequences, the P and P\sp\prime arms. Within the core, there are two Int core-type binding sites. The flanking arm sequences contain binding sites for Int as well as for IHF, Xis, and FIS. This array of protein-DNA interactions forms a higher-order complex, the intasome, which is the active substrate for recombination.Using the P22-based challenge-phage system, we have developed an in vivo assay to analyze both core binding and the long range interactions required for attL complex formation. The DNA sequences for the core alone as well as for the core plus the P\sp\prime arm of attP have been cloned into the operator region and thus regulate the P22 antirepressor (ant) operon. In this system, the core sequence alone is not sufficient repression. However, in the attL (I) challenge phage, the P\sp\prime arm enhances core-Int interaction so that transcription is inhibited. In addition, the core and H\sp\prime sites enhance Int-arm type binding as well. These long range interactions require both Int and IHF and suggest that IHF, interacting with its H\sp\prime site, bends the DNA so that the Int molecules bound to the arm-type sites are brought into close proximity to and thus can interact with the core. By a combination mutagenesis techniques, we have shown that the major binding-site determinants of the attL complex are the C\sp\prime, H\sp\prime, and P\sp\prime1 sites. Both the C and the P\sp\prime2 sites are also involved in complex formation.Finally, I have used these attL challenge phage to characterize the DNA binding abilities of a group of Int mutants. With this analysis, I have been able to show that the evolutionarily conserved (his)-308 and (arg)-311 residues play a role in core binding.Made available in DSpace on 2011-05-07T14:13:18Z (GMT). No. of bitstreams: 2
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Semigroup Rings And The Extension Theorem For Linear Codes
No full text. An extension theorem for general weight functions is proved over finite commutative local principal ideal rings. The structure of the complex semigroup ring associated to the multiplicative semigroup of the ring plays a prominent role in the proof. 1. Background In her doctoral dissertation, MacWilliams [8], [9] proved an equivalence theorem: two linear codes C 1 ; C 2 ae F n defined over a finite field F are equivalent up to monomial transformations if and only if there is a linear isomorphism f : C 1 ! C 2 which preserves Hamming weight. Bogart et al. [2] gave another proof of this theorem, and a character theoretic proof was provided by Ward and the author [13]. Following up on the ideas in [13], the author has extended the character theoretic techniques to linear codes defined over finite Frobenius rings, first for the Hamming weight [15] and then for symmetrized weight compositions [16]. In this paper, the author treats general weight functions defined over finite commutat..
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