Universal deformation rings and generalized quaternion defect groups

We determine the universal deformation ring R(G,V) of certain mod 2 representations V of a finite group G which belong to a 2-modular block of G whose defect groups are isomorphic to a generalized quaternion group D. We show that for these V, a question raised by the author and Chinburg concerning the relation of R(G,V) to D has an affirmative answer. We also show that R(G,V) is a complete intersection even though R(G/N,V) need not be for certain normal subgroups N of G which act trivially on V.Comment: 20 pages, 6 figures. The paper has been updated as follows: The results remain true for more general 2-modular blocks with generalized quaternion defect groups (see the introduction and Hypothesis 3.1). Sections 4 and 5 have been swapped

SU(3) Baryon Resonance Multiplets in Large N_c QCD

We extend the recently developed treatment of baryon resonances in large N_c QCD to describe resonance multiplets collected according to the SU(3) flavor symmetry that includes strange quarks. As an illustration we enumerate the SU(3) partners of a hypothetical J^P = 1/2^{+/-} resonance in the SU(3) representation that reduces to 10-bar when N_c = 3, and reproduce results hitherto obtained only in the context of a large N_c quark picture. While these specific quantum numbers represent one favored set for the possible pentaquark state Theta^+ (1540), the method is applicable to baryon resonances with any quantum numbers.Comment: 14 pages, ReVTe

Novel NN interaction and the spectroscopy of light nuclei

Nucleon-nucleon (NN) phase shifts and the spectroscopy of $A \le 6$ nuclei are successfully described by an inverse scattering potential that is separable with oscillator form factors.Comment: 4 pages, 1 figure, 13 table

Universal deformation rings for the symmetric group S_4

Let k be an algebraically closed field of characteristic 2, and let W be the ring of infinite Witt vectors over k. Let S_4 denote the symmetric group on 4 letters. We determine the universal deformation ring R(S_4,V) for every kS_4-module V which has stable endomorphism ring k and show that R(S_4,V) is isomorphic to either k, or W[t]/(t^2,2t), or the group ring W[Z/2]. This gives a positive answer in this case to a question raised by the first author and Chinburg whether the universal deformation ring of a representation of a finite group with stable endomorphism ring k is always isomorphic to a subquotient ring of the group ring over W of a defect group of the modular block associated to the representation.Comment: 12 pages, 2 figure

Chiral soliton models, large N_c consistency and the Theta^+ exotic baryon

Predictions for a light collective $\Theta^+$ baryon state (with strangeness +1) based on the collective quantization of chiral soliton models are shown to be inconsistent with large $N_c$ QCD. The lightest strangeness +1 state to emerge from the analysis has an excitation energy which at large $N_c$ scales as $N_c^0$ while collective quantization is legitimate only for excitations which go to zero as $N_c \to \infty$. This inconsistency strongly suggests that predictions for $\Theta^+$ properties based on collective quantization of chiral solitons are not valid.Comment: 5 pages, 1 figure. This is the version to be published; minor typos have been corrected and a reference adde

Magnetic moments of exotic pentaquarks in the chiral quark-soliton model

We investigate the magnetic moments of the baryon antidecuplet within the framework of the chiral quark-soliton model in the chiral limit in a ``\emph{model-independent}'' approach. Sum rules for the magnetic moments are derived. The magnetic moment of $\Theta^{+}$ is found to be about $0.2\sim 0.3 \mu_{N}$.Comment: 9 pages, 1 figure, submitted to Phys. Lett. B. The title was changed. One sign mistake was removed with the text extended. One author is adde

Universal deformation rings for the symmetric group S_5 and one of its double covers

Let $S_5$ denote the symmetric group on 5 letters, and let $\hat{S}_5$ denote a non-trivial double cover of $S_5$ whose Sylow 2-subgroups are generalized quaternion. We determine the universal deformation rings $R(S_5,V)$ and $R(\hat{S}_5,V)$ for each mod 2 representation $V$ of $S_5$ that belongs to the principal 2-modular block of $S_5$ and whose stable endomorphism ring is given by scalars when it is inflated to $\hat{S}_5$. We show that for these $V$, a question raised by the first author and Chinburg concerning the relation of the universal deformation ring of $V$ to the Sylow 2-subgroups of $S_5$ and $\hat{S}_5$, respectively, has an affirmative answer.Comment: 10 pages, 5 figures; the proof of Theorem 1.1(a) has been shortene

Relationship between Protein kinase C and derepression of different enzymes

The PKC1 gene in the yeast Saccharomyces cerevisiae encodes for protein kinase C which is known to control a MAP kinase cascade consisting of different kinases: Bck1, Mkk1 and Mkk2, and Mpk1. This cascade affects the cell wall integrity but the phenotype of pkc1∆ mutants suggests additional targets that have not yet been identified [1]. The pkc1∆ mutant, as opposed to other mutants in the MAP kinase cascade, displays defects in the control of carbon metabolism. One of them occurs in the derepression of SUC2 gene after exhaustion of glucose from the medium suggesting an involvement of Pkc1p in the derepression process that is not shared by the downstream MAP kinase cascade. In this work, we demonstrate that Pkc1p is required for the increase of the activity of enzymatic systems during derepression process. We observed that Pkc1p is involved in the derepression of invertase and alcohol dehydrogenase activities. On the other hand, it seems not to be necessary for the derepression of the enzymes of the GAL system. Our results suggest that Pkc1p is acting through the main glucose repression pathway since introduction of an additional mutation in the PKC1 gene in yeast strains already presenting mutations in the HXKII or MIG1 genes does not interfere with the typical derepressed phenotype observed in these single mutants. Moreover, our data indicate that Pkc1p participates in this process through the control of the cellular localization of the Mig1 transcriptional factor.Fundação de Amparo a Pesquisa do Estado de Minas Gerais – FAPEMIG (Brasil) Process CBS-1875/95 to R.L.B.Ministério da Educação. Fundação de Capacitação de Pessoal Docente (Brasil).Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (Brasil) Process 300998/89-9

METTL13 methylation of eEF1A increases translational output to promote tumorigenesis

Increased protein synthesis plays an etiologic role in diverse cancers. Here, we demonstrate that METTL13 (methyltransferase-like 13) dimethylation of eEF1A (eukaryotic elongation factor 1A) lysine 55 (eEF1AK55me2) is utilized by Ras-driven cancers to increase translational output and promote tumorigenesis in vivo. METTL13-catalyzed eEF1A methylation increases eEF1A's intrinsic GTPase activity in vitro and protein production in cells. METTL13 and eEF1AK55me2 levels are upregulated in cancer and negatively correlate with pancreatic and lung cancer patient survival. METTL13 deletion and eEF1AK55me2 loss dramatically reduce Ras-driven neoplastic growth in mouse models and in patient-derived xenografts (PDXs) from primary pancreatic and lung tumors. Finally, METTL13 depletion renders PDX tumors hypersensitive to drugs that target growth-signaling pathways. Together, our work uncovers a mechanism by which lethal cancers become dependent on the METTL13-eEF1AK55me2 axis to meet their elevated protein synthesis requirement and suggests that METTL13 inhibition may constitute a targetable vulnerability of tumors driven by aberrant Ras signaling.We thank Pal Falnes, Jerry Pelletier, and Julien Sage for helpful discussion, Lauren Brown and William Devine for SDS-1-021, and members of the Gozani and Mazur laboratories for critical reading of the manuscript. This work was supported in part by grants from the NIH to S.M.C. (K99CA190803), M.P.K. (5K08CA218690-02), J.A.P. (R35GM118173), M.C.B. (1DP2HD084069-01), J.S. (1R35GM119721), I.T. (R01CA202021), P.K.M. (R00CA197816, P50CA070907, and P30CA016672), and O.G. (R01GM079641). J.E.E. received support from Stanford ChEM-H, and A.M. was supported by the MD Anderson Moonshot Program. I.T. is a Junior 2 Research Scholar of the Fonds de Recherche du Quebec - Sante (FRQ-S). P.K.M. is supported by the Neuroendocrine Tumor Research Foundation and American Association for Cancer Research and is the Andrew Sabin Family Foundation Scientist and CPRIT scholar (RR160078). S.H. is supported by a Deutsche Forschungsgemeinschaft Postdoctoral Fellowship. J.W.F. is supported by 5T32GM007276. (K99CA190803 - NIH; 5K08CA218690-02 - NIH; R35GM118173 - NIH; 1DP2HD084069-01 - NIH; 1R35GM119721 - NIH; R01CA202021 - NIH; R00CA197816 - NIH; P50CA070907 - NIH; P30CA016672 - NIH; R01GM079641 - NIH; Stanford ChEM-H; MD Anderson Moonshot Program; Neuroendocrine Tumor Research Foundation; American Association for Cancer Research; Deutsche Forschungsgemeinschaft Postdoctoral Fellowship; 5T32GM007276)Supporting documentationAccepted manuscrip

Hydrologic connectivity and land cover affect floodplain lake water quality, fish abundance, and fish diversity in floodplain lakes of the Wabash-White River basin

Floodplain lakes are important aquatic resources for supporting ecosystem services, such as organismal habitat, biodiversity, and the retention of nutrients and sediment. Due to geomorphic alteration of river channels and land-cover change, degradation to floodplain lakes in the Ohio River basin is occurring at a rate that will escalate as climate change causes increased flood intensity and the seasonal redistribution of rainfall. A better understanding of the local drivers that affect oxbow lakes is needed for targeted floodplain restoration efforts designed to slow degradation. We examined the effects of land cover, topography, and hydrologic connectivity on water quality and fish diversity and abundance in nine floodplain lakes with potentially high remnant ecological function in the Wabash-White watershed (Indiana, Ohio, and Illinois). Data collection included water-quality parameters; stable water isotopes; total phosphorus, total nitrogen, and chlorophyll-a; and fish community diversity and abundance. Results indicate that hay/pasture land cover and decreased topographic relief in the local oxbow watersheds, along with reduced river hydrologic connectivity, were related to an increase in total phosphorus, total nitrogen, and chlorophyll-a. Greater biodiversity and abundance in fish assemblages were evident in oxbow lakes that were more disconnected from the main channel. The results of this study suggest that hydrologic connectivity of oxbow lakes with the contributing drainage area and the main channel influence nutrients and fish communities. Knowing the influencing factors can help ecosystem managers better protect these valuable floodplain lake ecosystems and prioritize restoration efforts amidst increasing stressors due to climate and land-use changes.Toyota Motor Manufacturing, Indiana, Inc.; Walton Family Foundatio