Biology subjects

Lozada, M.

Publications and source records attributed to Lozada, M..

4 recordsLinked to original sources

bioRxiv2023

The Shape of Cannabis sativa L. Seeds for the Differentiation of Commercial Medicinal Cultivars from Argentina.

The Cannabis sativa L. plant has been used since ancient times as food, a source of fiber, and medicine, resulting in crosses that led to hybridization that currently does not allow for morphological differentiation among the three varieties of the genus (sativa, indica, and ruderalis). Currently, three chemotypes are differentiated based on their cannabinoid content (THC/CBD). Starting in the year 2023, seeds of two contrasting chemotype medicinal cultivars developed by CONICET (National Council for Scientific and Technical Research) and registered with INASE (National Institute of Seeds) can be commercialized in Argentina. In a previous study, we reported a relationship between the shape of Cannabis seeds and the chemical fingerprint associated with the chemotype. The objective of this study is to morphometrically characterize the seeds of two cultivars of Cannabis sativa L. with contrasting chemotypes: type I (high THC) and type III (high CBD). For this purpose, 2D geometric morphometrics based on landmarks and semilandmarks were used, allowing for the independent study of shape and size variation. Seed size between cultivars was compared using univariate statistics of an unbiased size estimator. To understand the magnitude and direction of shape change and determine shape characters that maximize separation between cultivars, a multivariate statistical approach was employed. Seeds belonging to the Malvina cultivar (type I cultivar, THC only) had, on average, smaller size and a rounded shape, whereas seeds from the Pachamama cultivar (type III, high CBD content) had larger size and a tendency towards an elongated oval shape. The use of a discriminant function based on seed shape allowed for over 97% correct assignments between cultivars. Our results could be used for implementing seed shape as a quality and authenticity seal for registered cultivars in the Argentine Cannabis market.

plant biology↗

bioRxiv2022

Distributed Compact Plasma Reactor Sterilization for Planetary Protection in Space Missions

This paper presents a proof-of-concept study establishing effectiveness of the Active Plasma Sterilizer (APS) for sterilization in planetary protection. The APS uses Compact Portable Plasma Reactors (CPPRs) to produce surface dielectric barrier discharge, a type of cold plasma, using ambient air to generate and distribute reactive species like ozone used for decontamination. Sterilization tests were performed with pathogenic bacteria (Escherichia coli and Bacillus subtilis) on materials (Aluminum, Polycarbonate, Kevlar and Orthofabric) relevant to space missions. Results show that the APS can achieve 4 to 5 log reductions of pathogenic bacteria on four selected materials, simultaneously at 11 points within 30 minutes, using power of 13.2 {+/-} 2.22 W. Spatial sterilization data shows the APS can uniformly sterilize several areas of a contaminated surface within 30 minutes. Ozone penetration through Kevlar and Orthofabric layers was achieved using the CPPR with no external agent assisting penetration. Preliminary material compatibility tests with SEM analysis of the APS exposed materials showed no significant material damage. Thus, this study shows the potential of the APS as a light-weight sustainable sterilization technology for planetary protection with advantages of uniform spatial decontamination, low processing temperatures, low exposure times, material compatibility and the ability to disinfect porous surfaces.

microbiology↗

bioRxiv2020

Undaria pinnatifida exudates trigger shifts in seawater chemistry and microbial communities from Atlantic Patagonian coasts

The invasive kelp Undaria pinnatifida has spread from northeastern Asia to temperate coastal environments worldwide, with profound effects on colonized ecosystems. In this work, we analyzed the effect of exudates from U. pinnatifida on the chemical and microbial properties of seawater from a semi-enclosed gulf from Atlantic Patagonia. Exudates of U. pinnatifida, consisting mainly of carbohydrates, were released at a rate of 1.6 {+/-} 0.8 mg C g-1 algae day-1, affecting the quality and optical properties of seawater in experimental incubations. Parallel factor analysis based on excitation-emission matrices collected from exudates revealed the presence of two humic-like and one non-humic fluorescent components. Exudate release stimulated microbial growth and polysaccharide degrading activity in seawater. After a 7-day incubation of fresh seawater with the exudates, changes in microbial community structure were analyzed by large-scale 16S rRNA gene amplicon sequencing. Copiotrophic and fermentative genera such as Spirochaeta (Spirochaetes) and Propionigenium (Fusobacteria) increased in the incubations with algal exudates. Genomic potential prediction revealed that the selected bacterial community could have higher ribosome content - an indicator of the potential for reaching higher metabolic rates - and genes for the degradation of complex organic compounds such as polysaccharides and other carbohydrates present in the exudates. Nutrient addition triggered the emergence of other microbial populations with different ecophysiological niches: unclassified Flavobacteriales, unclassified bacteria related to the recently described Phylum Kiritimatiellaeota, as well as potential pathogens such as Vibrio (Gammaproteobacteria) and Arcobacter (Epsilonproteobacteria), suggesting potential synergistic effects between invasive macroalgae and human activities.

microbiology↗

bioRxiv2020

Metabarcoding, direct stomach observation and stable isotope analysis reveal a highly diverse diet for the invasive green crab in Atlantic Patagonia

The European green crab Carcinus maenas and its sister species C. aestuarii are highly invasive species causing damage to coastal ecosystems and contributing to severe economic losses worldwide. C. maenas was first detected at the Atlantic Patagonian coast in 2001. In this work, we studied the diet of the green crab in a recently invaded location in Golfo Nuevo, using three complementary techniques: direct stomach observation, metabarcoding of gut content and stable isotope analysis. Direct stomach observation and metabarcoding showed that green crabs have a broad omnivorous diet, ingesting most of the phyla present in the study area. Gut content metabarcoding allowed a detailed description of algal diversity and revealed other taxa that went unnoticed in the visual stomach analysis. Stable isotope analysis showed that the major contribution to the crabs diet was from the phytoplankton chain (by bivalve consumption) and not directly from algae. This study approach combining three complementary techniques also allowed us to detect some differences in the diet between sexes, which suggests that male and female crabs are not as ecologically equivalent as previously thought. Besides, we detected sequences corresponding to C. aestuarii suggesting that the green crab Patagonian population is a hybrid of both sister species. These findings are key to understanding the impacts green crabs can have on the local ecosystem.

ecology↗