Counting Arithmetical Structures on Paths and Cycles

Let G be a finite, connected graph. An arithmetical structure on G is a pair of positive integer vectors d, r such that (diag (d) - A) r=0 , where A is the adjacency matrix of G. We investigate the combinatorics of arithmetical structures on path and cycle graphs, as well as the associated critical groups (the torsion part of the cokernels of the matrices (diag (d) - A)). For paths, we prove that arithmetical structures are enumerated by the Catalan numbers, and we obtain refined enumeration results related to ballot sequences. For cycles, we prove that arithmetical structures are enumerated by the binomial coefficients ((2n-1)/(n-1)) , and we obtain refined enumeration results related to multisets. In addition, we determine the critical groups for all arithmetical structures on paths and cycles

Counting Arithmetical Structures on Paths and Cycles

Let G be a finite, connected graph. An arithmetical structure on G is a pair of positive integer vectors d, r such that (diag (d) - A) r=0 , where A is the adjacency matrix of G. We investigate the combinatorics of arithmetical structures on path and cycle graphs, as well as the associated critical groups (the torsion part of the cokernels of the matrices (diag (d) - A)). For paths, we prove that arithmetical structures are enumerated by the Catalan numbers, and we obtain refined enumeration results related to ballot sequences. For cycles, we prove that arithmetical structures are enumerated by the binomial coefficients ((2n-1)/(n-1)) , and we obtain refined enumeration results related to multisets. In addition, we determine the critical groups for all arithmetical structures on paths and cycles

Expanding the recombinant protein quality in Lactococcus lactis

Background: Escherichia coli has been a main host for the production of recombinant proteins of biomedical interest, but conformational stress responses impose severe bottlenecks that impair the production of soluble, proteolytically stable versions of many protein species. In this context, emerging Generally Recognized As Safe (GRAS) bacterial hosts provide alternatives as cell factories for recombinant protein production, in which limitations associated to the use of Gram-negative microorganisms might result minimized. Among them, Lactic Acid Bacteria and specially Lactococcus lactis are Gram-positive GRAS organisms in which recombinant protein solubility is generically higher and downstream facilitated, when compared to E. coli. However, deep analyses of recombinant protein quality in this system are still required to completely evaluate its performance and potential for improvement. - Results : we have explored here the conformational quality (through specific fluorescence emission) and solubility of an aggregation-prone GFP variant (VP1GFP) produced in L. lactis. In this context, our results show that parameters such as production time, culture conditions and growth temperature have a dramatic impact not only on protein yield, but also on protein solubility and conformational quality, that are particularly favored under fermentative metabolism. - Conclusions: metabolic regime and cultivation temperature greatly influence solubility and conformational quality of an aggregation-prone protein in L. lactis. Specifically, the present study proves that anaerobic growth is the optimal condition for recombinant protein production purposes. Besides, growth temperature plays an important role regulating both protein solubility and conformational quality. Additionally, our results also prove the great versatility for the manipulation of this bacterial system regarding the improvement of functionality, yield and quality of recombinant proteins in this species. These findings not only confirm L. lactis as an excellent producer of recombinant proteins but also reveal room for significant improvement by the exploitation of external protein quality modulators

Automated radiofrequency-based US measurement of common carotid intima-media thickness in RA patients treated with synthetic vs synthetic and biologic DMARDs

Objective. To compare the carotid intima-media thickness (IMT) assessed with automated radiofrequency-based US in RA patients treated with synthetic vs synthetic and biologic DMARDs and controls. Methods. Ninety-four RA patients and 94 sex-and age-matched controls were prospectively recruited at seven centres. Cardiovascular (CV) risk factors and co-morbidities, RA characteristics and therapy were recorded. Common carotid artery (CCA)-IMT was assessed in RA patients and controls with automated radiofrequency-based US by the same investigator at each centre. Results. Forty-five (47.9%) RA patients had been treated with synthetic DMARDs and 49 (52.1%) with synthetic and biologic DMARDs. There were no significant differences between the RA patients and controls in demographics, CV co-morbidities and CV disease. There were significantly more smokers among RA patients treated with synthetic and biologic DMARDs (P = 0.036). Disease duration and duration of CS and synthetic DMARD therapy was significantly longer in RA patients treated with synthetic and biologic DMARDs (P<0.0005). The mean CCA-IMT was significantly greater in RA patients treated only with synthetic DMARDs than in controls [591.4 (98.6) vs 562.1 (85.8); P = 0.035] and in RA patients treated with synthetic and biologic DMARDs [591.4 (98.6) vs 558.8 (95.3); P = 0.040). There was no significant difference between the mean CCA-IMT in RA patients treated with synthetic and biologic DMARDs and controls (P = 0.997). Conclusion. Our results suggest that radiofrequency-based measurement of CCA-IMT can discriminate between RA patients treated with synthetic DMARDs vs RA patients treated with synthetic and biologic DMARDs

The effect of ultrasound pretreatment on some selected physicochemical properties of black cumin (Nigella Sativa)

Background In the present study, the effects of ultrasound pretreatment parameters including irradiation time and power on the quantity of the extracted phenolic compounds quantity as well as on some selected physicochemical properties of the extracted oils including oil extraction efficiency, acidity and peroxide values, color, and refractive index of the extracted oil of black cumin seeds with the use of cold press have been studied. Methods For each parameter, three different levels (30, 60, and 90 W) for the ultrasound power and (30, 45, and 60 min) and for the ultrasound irradiation time were studied. Each experiment was performed in three replications. Results The achieved results revealed that, with enhancements in the applied ultrasound power, the oil extraction efficiency, acidity value, total phenolic content, peroxide value, and color parameters increased significantly (P 0.05). Conclusions In summary, it could be mentioned that the application of ultrasound pretreatment in the oil extraction might improve the oil extraction efficiency, the extracted oil’s quality, and the extracted phenolic compounds content.info:eu-repo/semantics/publishedVersio

Impaired liver regeneration in mice lacking methionine adenosyltransferase 1A

Methionine adenosyltransferase (MAT) is an essential enzyme because it catalyzes the formation of S-adenosylmethionine (SAMe), the principal biological methyl donor. Of the two genes that encode MAT, MAT1A is mainly expressed in adult liver and MAT2A is expressed in all extrahepatic tissues. Mice lacking MAT1A have reduced hepatic SAMe content and spontaneously develop hepatocellular carcinoma. The current study examined the influence of chronic hepatic SAMe deficiency on liver regeneration. Despite having higher baseline hepatic staining for proliferating cell nuclear antigen, MAT1A knockout mice had impaired liver regeneration after partial hepatectomy (PH) as determined by bromodeoxyuridine incorporation. This can be explained by an inability to up-regulate cyclin D1 after PH in the knockout mice. Upstream signaling pathways involved in cyclin D1 activation include nuclear factor kappaB (NFkappaB), the c-Jun-N-terminal kinase (JNK), extracellular signal-regulated kinases (ERKs), and signal transducer and activator of transcription-3 (STAT-3). At baseline, JNK and ERK are more activated in the knockouts whereas NFkappaB and STAT-3 are similar to wild-type mice. Following PH, early activation of these pathways occurred, but although they remained increased in wild-type mice, c-jun and ERK phosphorylation fell progressively in the knockouts. Hepatic SAMe levels fell progressively following PH in wild-type mice but remained unchanged in the knockouts. In culture, MAT1A knockout hepatocytes have higher baseline DNA synthesis but failed to respond to the mitogenic effect of hepatocyte growth factor. Taken together, our findings define a critical role for SAMe in ERK signaling and cyclin D1 regulation during regeneration and suggest chronic hepatic SAMe depletion results in loss of responsiveness to mitogenic signals

Linkage mapping of the Phg-1 and Co-14 genes for resistance to angular leaf spot and anthracnose in the common bean cultivar AND 277

The Andean common bean AND 277 has the Co-14 and the Phg-1 alleles that confer resistance to 21 and eight races, respectively, of the anthracnose (ANT) and angular leaf spot (ALS) pathogens. Because of its broad resistance spectrum, Co-14 is one of the main genes used in ANT resistance breeding. Additionally, Phg-1 is used for resistance to ALS. In this study, we elucidate the inheritance of the resistance of AND 277 to both pathogens using F2 populations from the AND 277 × Rudá and AND 277 × Ouro Negro crosses and F2:3 families from the AND 277 × Ouro Negro cross. Rudá and Ouro Negro are susceptible to all of the above races of both pathogens. Co-segregation analysis revealed that a single dominant gene in AND 277 confers resistance to races 65, 73, and 2047 of the ANT and to race 63-23 of the ALS pathogens. Co-14 and Phg-1 are tightly linked (0.0 cM) on linkage group Pv01. Through synteny mapping between common bean and soybean we also identified two new molecular markers, CV542014450 and TGA1.1570, tagging the Co-14 and Phg-1 loci. These markers are linked at 0.7 and 1.3 cM, respectively, from the Co-14/Phg-1 locus in coupling phase. The analysis of allele segregation in the BAT 93/Jalo EEP558 and California Dark Red Kidney/Yolano recombinant populations revealed that CV542014450 and TGA1.1570 segregated in the expected 1:1 ratio. Due to the physical linkage in cis configuration, Co-14 and Phg-1 are inherited together and can be monitored indirectly with the CV542014450 and TGA1.1570 markers. These results illustrate the rapid discovery of new markers through synteny mapping. These markers will reduce the time and costs associated with the pyramiding of these two disease resistance genes