Emerging Applications of Chlorella sp. and Spirulina (Arthrospira) sp.

Chlorella sp. and Spirulina (Arthrospira) sp. account for over 90% of the global microalgal biomass production and represent one of the most promising aquiculture bioeconomy systems. These microorganisms have been widely recognized for their nutritional and therapeutic properties; therefore, a significant growth of their market is expected, especially in the nutraceutical, food, and beverage segments. However, recent advancements in biotechnology and environmental science have led to the emergence of new applications for these microorganisms. This paper aims to explore these innovative applications, while shedding light on their roles in sustainable development, health, and industry. From this state-of-the art review, it was possible to give an in-depth outlook on the environmental sustainability of Chlorella sp. and Spirulina (Arthrospira) sp. For instance, there have been a variety of studies reported on the use of these two microorganisms for wastewater treatment and biofuel production, contributing to climate change mitigation efforts. Moreover, in the health sector, the richness of these microalgae in photosynthetic pigments and bioactive compounds, along with their oxygen-releasing capacity, are being harnessed in the development of new drugs, wound-healing dressings, photosensitizers for photodynamic therapy, tissue engineering, and anticancer treatments. Furthermore, in the industrial sector, Chlorella sp. and Spirulina (Arthrospira) sp. are being used in the production of biopolymers, fuel cells, and photovoltaic technologies. These innovative applications might bring different outlets for microalgae valorization, enhancing their potential, since the microalgae sector presents issues such as the high production costs. Thus, further research is highly needed to fully explore their benefits and potential applications in various sectors.

Molecular and morphometric identification of Trypanosoma (Megatrypanum) minasense in blood samples of marmosets (Callithrix: Callithrichidae) from the city of Rio de Janeiro, Brazil.

Callithrix jacchus and C. penicillata marmosets are invasive to the state of Rio de Janeiro, Brazil, threatening the native and vulnerable C. aurita. Both invasive species can be hosts of Trypanosoma cruzi, T. minasense, T. rangeli and T. devei. We aim to investigate the occurrence of trypanosomatids in Callithrix sp. from Jardim Botânico do Rio de Janeiro, located in a central and populous area of the city. Fifteen marmosets were captured. Blood samples were collected for light microscopy and molecular genetics analysis. Parasites morphometric values were evaluated for species identification. DNA was extracted from blood samples by phenol-chloroform method, for partial amplification of the 18S rRNA gene. PCR products were sequenced and aligned using BLAST®. A maximum likelihood phylogenetic tree was constructed to analyze the proximity between the observed sequences. By light microscopy, trypomastigotes were detected in five of the fifteen marmosets. Morphometric measurements and size polymorphism corresponded to those previously described for T. minasense. The DNA sequences of approximately 600 base pairs of the 18S rRNA gene were obtained for three samples with 99% identity with T. minasense sequence, forming a cluster in the phylogenetic tree and corroborating morphometric analysis. Trypanosoma minasense is a highly specific parasite to non-human primates considered as non-pathogenic. There is no evidence of infection in humans and these parasite findings from invasive marmosets do not support additional risks for the native species.

Hypothalamic miR-30 regulates puberty onset via repression of the puberty-suppressing factor, Mkrn3.

Mkrn3, the maternally imprinted gene encoding the makorin RING-finger protein-3, has recently emerged as putative pubertal repressor, as evidenced by central precocity caused by MKRN3 mutations in humans; yet, the molecular underpinnings of this key regulatory action remain largely unexplored. We report herein that the microRNA, miR-30, with three binding sites in a highly conserved region of its 3' UTR, operates as repressor of Mkrn3 to control pubertal onset. Hypothalamic miR-30b expression increased, while Mkrn3 mRNA and protein content decreased, during rat postnatal maturation. Neonatal estrogen exposure, causing pubertal alterations, enhanced hypothalamic Mkrn3 and suppressed miR-30b expression in female rats. Functional in vitro analyses demonstrated a strong repressive action of miR-30b on Mkrn3 3' UTR. Moreover, central infusion during the juvenile period of target site blockers, tailored to prevent miR-30 binding to Mkrn3 3' UTR, reversed the prepubertal down-regulation of hypothalamic Mkrn3 protein and delayed female puberty. Collectively, our data unveil a novel hypothalamic miRNA pathway, involving miR-30, with a prominent role in the control of puberty via Mkrn3 repression. These findings expand our current understanding of the molecular basis of puberty and its disease states.

Mixotrophic cultivation of Chlorella vulgaris using industrial dairy waste as organic carbon source.

Growth parameters and biochemical composition of the green microalga Chlorella vulgaris cultivated under different mixotrophic conditions were determined and compared to those obtained from a photoautotrophic control culture. Mixotrophic microalgae showed higher specific growth rate, final biomass concentration and productivities of lipids, starch and proteins than microalgae cultivated under photoautotrophic conditions. Moreover, supplementation of the inorganic culture medium with hydrolyzed cheese whey powder solution led to a significant improvement in microalgal biomass production and carbohydrate utilization when compared with the culture enriched with a mixture of pure glucose and galactose, due to the presence of growth promoting nutrients in cheese whey. Mixotrophic cultivation of C. vulgaris using the main dairy industry by-product could be considered a feasible alternative to reduce the costs of microalgal biomass production, since it does not require the addition of expensive carbohydrates to the culture medium.