Biology subjects

Lorenzo, C.

Publications and source records attributed to Lorenzo, C..

5 recordsLinked to original sources

bioRxiv2025

Replication Timing Uncovers a Two-Compartment Nuclear Architecture of Interphase Euchromatin in Maize

Genome replication is temporally regulated during S phase, with specific genomic regions replicating at defined times in a process that is known as replication timing (RT). Based on 3D cytology in replicating nuclei, we previously proposed a "mini-domain chromatin fiber RT model" for maize euchromatin that suggested it is subdivided into early-S and middle-S compartments distinguished by chromatin condensation and RT. However, whether this compartmentalization reflects a general nuclear architecture that persists throughout the cell cycle was unclear. To test this model, we conducted two orthogonal assays - Hi-C for genome-wide interaction data and 3D FISH for direct visualization of chromatin organization. Hi-C eigenvalues and insulation scores revealed distinct patterns of early-S regions having negative insulation scores with long-range contacts while middle-S regions showed the opposite. Early-S regions correlated more strongly with epigenomic signatures of open, transcriptionally active chromatin than middle-S regions. 3D oligo FISH painting confirmed that early-S and middle-S regions occupy adjacent but largely non-overlapping nucleoplasmic spaces during all interphase stages, including G1. Our findings redefine the maize euchromatin "A" compartment as having two distinct, closely interspersed subcompartments, early-S and middle-S, underscoring the importance of replication timing (RT) as a defining feature of chromatin architecture and genome organization.

genetics↗

bioRxiv2025

Urban crops demonstrate comparable potential for organic carbon storage as natural ecosystems.

Urban greenspaces, encompassing parks, golf courses, roundabouts, and urban crops, have potential to offset urban carbon footprints by storing soil organic carbon (SOC). This study analyzed particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) stocks in topsoil across 27 Iberian cities, comparing urban greenspaces with natural ecosystems under varying climatic and edaphic conditions. Results revealed that urban greenspaces store comparable SOC stocks to natural ecosystems, with MAOC stocks being more dominant and stable across land-use types. POC stocks showed variability, particularly lower in roundabouts and parks compared to natural ecosystems, but remained similar in golf courses and urban crops. SOC fractions correlated inversely with mean annual temperature (MAT), emphasizing the need for cooling strategies in urban areas to preserve stable carbon pools. While MAOC exhibited saturation at higher SOC levels, POC showed a linear increase. This study highlights the importance of tailored management practices to enhance carbon storage in urban soils for climate change mitigation.

biochemistry↗

bioRxiv2021

MDA-LDL vaccination induces athero-protective germinal center-derived antibody responses

Atherosclerosis is a chronic inflammatory disease of the arteries that can lead to thrombosis, infarction and stroke and is the leading cause of mortality worldwide. Immunization of pro-atherogenic mice with malondialdehyde-modified low-density lipoprotein (MDA-LDL) neo-antigen is athero-protective. However, the immune response to MDA-LDL and the mechanisms responsible for this athero-protection are not completely understood. Here, we find that immunization of mice with MDA-LDL elicits memory B cells, plasma cells, and switched anti-MDA-LDL antibodies as well as clonal expansion and affinity maturation, indicating that MDA-LDL triggers a bona fide germinal center antibody response. Further, Prdm1fl/fl Aicda-Cre+/ki Ldlr-/- pro-atherogenic chimeras, which lack germinal center-derived plasma cells, show accelerated atherosclerosis. Finally, we show that MDA-LDL immunization is not athero-protective in mice lacking germinal-center derived plasma cells. Our findings give further support to the development of MDA-LDL-based vaccines for the prevention or treatment of atherosclerosis.

immunology↗

bioRxiv2020

Characterizing the body morphology of the first metacarpal in the Homininae using 3D geometric morphometrics

ObjectivesThe morphological characteristics of the thumb are of particular interest due to its fundamental role in enhanced manipulation. Despite its possible importance regarding this issue, the body of the first metacarcapal (MC1) has not been fully characterized using morphometrics. This could provide further insights into its anatomy, as well as its relationship with manipulative capabilities. Hence, this study quantifies the shape of the MC1s body in the extant Homininae and some fossil hominins to provide a better characterization of its morphology. Materials and methodsThe sample includes MC1s of modern humans (n=42), gorillas (n=27) and chimpanzees (n=30), as well as Homo neanderthalensis, Homo naledi and Australopithecus sediba. 3D geometric morphometrics were used to quantify the shape of MC1s body. ResultsThe results show a clear distinction among the three extant genera. H. neanderthalensis mostly falls within the modern human range of variation. H. naledi varies slightly from modern humans, although also showing some unique trait combination, whereas A. sediba varies to an even greater extent. When classified using a discriminant analysis, the three fossils are categorized within the Homo group. Conclusion: The modern human MC1 is characterized by a distinct suite of traits, not present to the same extent in the great apes, that are consistent with an ability to use forceful precision grip. This morphology was also found to align very closely with that of H. neanderthalensis. H. naledi shows a number of human-like adaptations, whilst A. sediba presents a mix of both derived and more primitive traits.

paleontology↗

bioRxiv2019

Detection of a novel African-lineage-like Zika virus naturally infecting free-living neotropical primates in Southern Brazil

Mosquito borne flaviviruses cause a series of important diseases in humans and animals. These viruses are maintained in cycles involving replication in mosquito and in vertebrate hosts. Most natural hosts are vertebrate animals living in sylvatic or peridomestic environments. Human contact with these environments may result in host shifts that lead to the establishment of urban transmission cycles. Zika virus is a Flavivirus that persists in nature in a transmission cycle involving non-human primates (NHP). Its recent emergence in Brazil has shed light upon the importance of surveying this agent in Brazilian sylvatic environments. Here we present histopathological and molecular evidence that free ranging howler monkeys (Alouatta guariba) in Southern Brazil are infected by ZIKV closely related to African lineage MR766. Nine NHP were nested RT-PCR positive for ZIKV RNA. Sequence analysis revealed 96 to 98% identity to ZIKV MR766 and 85% identity to ZIKV P6-740, the current epidemic strain. The affected howler monkeys presented discrete inflammatory infiltrates in several tissues and immunohistochemichal (IHC) labeling of viral antigen was observed in placenta. These findings point to the circulation of African lineage Zika virus in the Americas in non-human primates. And raises the possibility that ZIKV was introduced into the Americas on more than one occasion.

microbiology↗