Biology subjects

Rumbo, M.

Publications and source records attributed to Rumbo, M..

3 recordsLinked to original sources

bioRxiv2026

The Cxcl14 chemokine defines pioneer axon guidance and early circuit assembly in the inner ear

The nervous system wiring requires the precise coordination of axon guidance, neuronal migration, and target cell recognition. Here, we show that inner ear circuit formation, relies on pioneer cells extending an axonal scaffold that selectively target nascent hair cells. High spatiotemporal imaging of pioneer axons reveal how they navigate through the cranial environment, establish dynamic cell-cell contacts with other axons to finally stabilize in target cells. These pioneer axons are required not only for follower axon growth but also for coordinated migration of follower neurons, revealing a cellular hierarchy underlying circuit assembly. We identify the chemokine Cxcl14 as a novel instructive guidance cue regulating pioneer axon extension, turning, and fasciculation at discrete cellular decision points. Loss of Cxcl14 disrupts axonal navigation, compromises synaptic organization in hair cells, and impairs mechanosensory-based behavior. Together, our findings establish a new chemokine-based mechanism linking pioneer axon guidance to early sensory circuit assembly necessary for building mechanosensory networks.

developmental biology↗

bioRxiv2022

Few amino acid mutations in H6 influenza A virus from South American lineage increase pathogenicity in poultry

In chickens, infections with influenza A virus (IAV) can range from mild to severe and lethal. The study of IAV infections in poultry has been mostly limited to strains from the North American and Eurasian lineages, whereas limited information exists on similar studies with strains from the South American lineage (SAm). To better evaluate the risk of introduction of a prototypical SAm IAV strain into poultry, chickens were infected with a wild-type SAm origin strain (WT557/H6N2). The resulting virus progeny was serially passage in chickens 20 times and the immunopathological effects in chickens of the last passage virus, 20Ch557/H6N2, was compared to those of the parental strain. Comparison of complete viral genome sequences indicated that the 20Ch557/H6N2 strain contained 13 amino acid differences compared to the wild type strain. Five of these mutations are in functionally relevant regions of the viral surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). However, despite higher and more prolonged virus shedding in chickens inoculated with the 20Ch557/H6N2 strain compared to those that received the WT557/H6N2 strain, transmission to naive chickens was not observed for either group. Analyses by flow cytometry of mononuclear cells and lymphocyte subpopulations from the lamina propria and intraepithelial lymphocytic cells (IELs) from ileum revealed significant increase in the percentages of CD3+TCR{gamma}{delta}+ IELs in chickens inoculated with the 20Ch557/H6N2 strain compared to those inoculated with the WT557/H6N2 strain.

microbiology↗

bioRxiv2020

A biorefinery concept for the production of fuel ethanol, probiotic yeast and whey protein from a by-product of the cheese industry

1.Agroindustrial by-products and residues can be transformed into valuable compounds in biorefineries. Here we present a new concept: production of fuel ethanol, whey protein and probiotic yeast from cheese whey. An initial screening under industrially relevant conditions, involving thirty Kluyveromyces marxianus strains, was carried out using spot assays to evaluate their capacity to grow on cheese whey or on whey permeate (100 g lactose/L), under aerobic or anaerobic conditions, in the absence or presence of 5% ethanol, at pH 5.8 or pH 2.5. The four best growing K. marxianus strains were selected and further evaluated in a miniaturized industrial fermentation process using reconstituted whey permeate (100 g lactose/L) with cell recycling (involving sulfuric acid treatment). After five consecutive fermentation cycles, the ethanol yield on sugar reached 90% of the theoretical maximum in the best cases, with 90% cell viability. Cells harvested at this point displayed probiotic properties such as capacity to survive the passage through the gastrointestinal tract and capacity to modulate innate immune response of intestinal epithelium, both in vitro. Furthermore, the CIDCA 9121 strain was able to protect against histopathological damage in an animal model of acute colitis. Our findings demonstrate that K. marxianus CIDCA 9121 is capable of efficiently fermenting the lactose present in whey permeate to ethanol and that the remaining yeast biomass has probiotic properties, enabling an integrated process for the obtainment of whey protein, fuel ethanol and probiotics from cheese whey. 2. ImportanceCheese whey is the liquid remaining following the precipitation and removal of milk casein during cheese-making. This by-product represents about 85-95% of the milk volume and retains 55% of milk nutrients so it can be exploited as a source of valuable end products. However, at a global level around 50% of cheese whey is wasted, representing an important environmental impact and indicating the need to develop alternative processes to recover value. Kluyveromyces marxianus is capable of fermenting lactose, generally regarded as safe, and has been explored separately as an ethanol producer and as a viable bioactive microorganism. The significance of our research is to establish the proof of concept that a biorefinery for fuel ethanol production using whey and K. marxianus can also be exploited to obtain viable probiotic biomass, conferring an added value to the process and providing an alternative to reduce environmental impact.

microbiology↗