Biology subjects

Torres, A. M.

Publications and source records attributed to Torres, A. M..

4 recordsLinked to original sources

bioRxiv2023

Comparative proteomic analysis of the hemolymph and salivary glands of Rhodnius prolixus and R. colombiensis reveals candidates associated with differential lytic activity against Trypanosoma cruzi I and T. cruzi II

BackgroundImmune response of triatomines plays an important role in the success or failure of transmission of T. cruzi. Studies on parasite-vector interaction have shown the presence of trypanolytic factors and have been observed to be differentially expressed among triatomines, which affects the transmission of some T. cruzi strains or DTUs (Discrete Typing Units). Methodology/Principal FindingsTrypanolytic factors were detected in the hemolymph and saliva of R. prolixus against epimastigotes and trypomastigotes of T. cruzi II. To identify the components of the immune response that could be involved in this lytic activity, a comparative proteomic analysis was carried out, detecting 120 proteins in the hemolymph of R. prolixus and 107 in R. colombiensis. In salivary glands, 1103 proteins were detected in R. prolixus and 853 in R. colombiensis. A higher relative abundance of lysozyme, prolixin, nitrophorins, and serpin as immune response proteins was detected in the hemolymph of R. prolixus. Among the R. prolixus salivary proteins, a higher relative abundance of nitrophorins, lipocalins, and triabins was detected. The higher relative abundance of these immune factors in R. prolixus supports their participation in the lytic activity on T. cruzi II, but not on T. cruzi I, which is resistant to lysis by hemolymph and salivary proteins of R. prolixus due to mechanisms of evading oxidative stress caused by immune factors. Conclusions/SignificanceT. cruzi I is a DTU distributed from the southern United States to the center of Chile and Argentina, and its successful spread across this range could be related to resistance to oxidative stress in vectors. Future proteomic and transcriptomic studies on vectors and the interactions of the intestinal microbiota with parasites will help to confirm the determinants of successful or failed vector transmission of T. cruzi DTUs in different parts of the Western Hemisphere. Author summarySome factors can facilitate or prevent T. cruzi transmission, i.e. vector immunity. Our work has managed to detect a stronger immune response against T. cruzi II in R. prolixus saliva and haemolymph, compared to that of R. colombiensis. Proteins from both species saliva and haemolymph were analysed for studying factors which might have been involved in such response; most proteins were detected in both species haemolymph, thereby indicating common immune mechanisms. Three proteins having oxidative immune activity were only expressed in R. prolixus. Lipocalin diversity and abundance predominated in R. prolixus saliva; these proteins are involved in nitric oxide metabolism and their role in immunity could be key in host defence against T. cruzi. Recognising the components modulating parasite transmission in a vector helps in understanding how such factors act independently and how they would act synergistically against T. cruzi, thereby enabling us to establish tools regarding Chagas disease epidemiology, aimed at predicting T. cruzi distribution and creating transmission control mechanisms.

microbiology↗

bioRxiv2022

Genetic analysis of global faba bean germplasm maps agronomic traits and identifies strong selection signatures for geographical origin

Faba bean (Vicia faba L.) is a high-protein grain legume crop with great potential for further cultivation. However, little is known about the genetics underlying trait diversity. In this study, we use 21,345 high-quality SNP markers to genetically characterise 2,678 faba bean genotypes. We perform genome-wide association studies of key agronomic traits using a Seven-parent-MAGIC population and detect 238 significant marker-trait associations linked to 12 traits of agronomic importance, with 65 of these being stable across multiple environments. Using a non-redundant diversity panel of 685 accessions from 52 countries, we identify 3 subpopulations differentiated by geographical origin and 33 genomic regions subject to strong diversifying selection between subpopulations. We find that SNP markers associated with the differentiation of northern and southern accessions were able to explain a significant proportion of agronomic trait variance in the Seven-parent-MAGIC population, suggesting that some of these traits have played an important role in breeding. Altogether, our findings point to genomic regions associated with important agronomic traits and selection in faba bean, which can be used for breeding purposes. Key MessageWe identified marker-trait associations for key faba bean agronomic traits and genomic signatures of selection within a global germplasm collection.

genetics↗

bioRxiv2020

A bHLH transcription factor (VfTT8) underlies zt2, the locus determining zero tannin content in faba bean (Vicia faba L.)

Faba bean (Vicia faba L.) is an important protein-rich fodder crop widely cultivated in temperate areas. However, antinutritional compounds such as condensed tannins, limit the use of this protein source in monogastric feed formulations. Previous studies demonstrated that two recessive and complementary genes, zt1 and zt2, control the absence of tannin and the white flower colour in faba bean. An ortholog of the Medicago WD40 transcription factor, (TTG1) was reported to encode the zt1 phenotypes but the responsible gene for zt2 is still unknown. A candidate gene approach combined with linkage mapping, comparative genomics and gene expression has been used in this study to fine map the zt2 genomic region and to identify the regulatory gene controlling both traits. Seventy-two genes, including 23 regulatory genes (MYB and bHLH) predicted to be associated with anthocyanin expression together with WRKY proteins were screened and genotyped in three mapping populations. The linkage groups constructed identified the regulatory gene, TRANSPARENT TESTA8 (TT8), encoding a basic helix-loop-helix transcription factor (bHLH), as the best candidate for zt2. This finding was supported by qPCR analyses and further validated in different genetic backgrounds. Accordingly, VfTT8 was down-regulated in white flowered types, in contrast to the levels of expression in wild genotypes. Our results provide new insights on the regulatory mechanisms for tannin biosynthesis in faba bean and will favour the development of an ultimate zt2 diagnostic marker for the fast generation of new value-added cultivars free of tannins and improved nutritional value.

genomics↗

bioRxiv2018

Bone-Inspired Microarchitectured Materials with Enhanced Fatigue Life

Microarchitectured materials achieve superior mechanical properties through geometry rather than composition 1-4. Although lightweight, high-porosity microarchitectured materials can have high stiffness and strength, stress concentrations within the microstructure can cause flaw intolerance under cyclic loading 5,6, limiting fatigue life. However, it is not known how microarchitecture contributes to fatigue life. Naturally occurring materials can display exceptional mechanical performance and are useful models for the design of microarchitectured materials 7,8. Cancellous bone is a naturally occurring microarchitectured material that often survives decades of habitual cyclic loading without failure. Here we show that resistance to fatigue failure in cancellous bone is sensitive to the proportion of material oriented transverse to applied loads - a 30% increase in density caused by thickening transversely oriented struts increases fatigue life by 10-100 times. This finding is surprising in that transversely oriented struts have negligible effects on axial stiffness, strength and energy absorption. The effects of transversely oriented material on fatigue life are also present in synthetic lattice microstructures. In both cancellous bone and synthetic microarchitectures, the fatigue life can be predicted using the applied cyclic stress after adjustment for apparent stiffness and the proportion of the microstructure oriented transverse to applied loading. In the design of microarchitectured materials, stiffness, strength and energy absorption is often enhanced by aligning the microstructure in a preferred direction. Our findings show that introduction of such anisotropy, by reducing the amount of material oriented transverse to loading, comes at the cost of reduced fatigue life. Fatigue failure of durable devices and components generates substantial economic costs associated with repair and replacement. As advancements in additive manufacturing expand the use of microarchitectured materials to reusable devices including aerospace applications, it is increasingly necessary to balance the need for fatigue life with those of strength and density.

bioengineering↗