Benthic Cyanobacterial Diversity and Antagonistic Interactions in Abrolhos Bank: Allelopathy, Susceptibility to Herbivory, and Toxicity

Benthic cyanobacterial mats (BCMs) are conspicuous components of coral reef communities, where they play key ecological roles as primary producers among others. BCMs often bloom and might outcompete neighboring benthic organisms, including reef-building corals. We investigated the cyanobacterial species composition of three BCMs morphotypes from the marginal reef complex of Abrolhos Bank (Southeastern Brazil). Also, we assessed their allelopathic effects on coral zooxanthellae, their susceptibility to herbivory by fish, and their toxicity to brine shrimp nauplii. Morphology and 16S rDNA sequencing unveiled the cyanobacteria Moorena bouillonii, Okeania erythroflocculosa, Adonisia turfae, Leptolyngbya sp., and Halomicronema sp. as components of BCMs from Abrolhos. BCMs cell-free filtrates and extracts exerted an allelopathic effect by reducing the growth of the ex hospite Symbiodinium sp. in culture. BCMs-only treatments remained untouched in field susceptibility assays in contrast to macroalgae only and mixed BCMs-macroalgae treatments that had the macroalgae fully removed by reef fish. Crude aqueous extracts from BCMs were toxic to brine shrimps in acute assays. Besides unveiling the diversity of BCMs consortia in Abrolhos, our results cast some light on their allelopathy, antiherbivory, and toxicity properties. These antagonistic interactions might promote adverse cascading effects during benthic cyanobacteria blooms and in gradual shifts to BCMs-dominated states.

Structure Elucidation and Toxicity Analysis of the Byproducts Formed after Biodegradation of Aflatoxins B1 and B2 Using Extracts of Mentha arvensis

The aqueous extracts of leaves and shoots of Mentha arvensis were checked for their potential to biodegrade aflatoxin B1 and B2 (AFB1; 100 µg/L and AFB2; 50 µg/L) through in vitro assays. Overall, the results showed that leaf extract degrades aflatoxins more efficiently than the shoot extract. First, the pH, temperature and incubation time were optimized for maximum degradation by observing this activity at different temperatures between 25 and 60 °C, pH between 2 and 10 and incubation time from 3 to 72 h. In general, an increase in all these parameters significantly increased the percentage of biodegradation. In vitro trials on mature maize stock were performed under optimized conditions, i.e., pH 8, temperature 30 °C and an incubation period of 72 h. The leaf extract resulted in 75% and 80% biodegradation of AFB1 and AFB2, respectively. Whereas the shoot extract degraded both toxins up to 40–48%. The structural elucidation of degraded toxin products by LCMS/MS analysis showed seven degraded products of AFB1 and three of AFB2. MS/MS spectra showed that most of the products were formed by the loss of the methoxy group from the side chain of the benzene ring, the removal of the double bond in the terminal furan ring and the modification of the lactone group, indicating less toxicity compared to the parent compounds. The degraded products showed low toxicity against brine shrimps, confirming that M. arvensis leaf extract has significant potential to biodegrade aflatoxins.

Antidiabetic, anti-inflammatory and cytotoxic potential of Theobroma cacao Linn. husk aqueous extracts

Background Theobroma cacao Linn. husks are considered agricultural wastes, but studies show that they exhibit natural compounds that may be used in alternative medicine. Hence, this study was conducted to determine the antidiabetic, anti-inflammatory, and cytotoxic potential of T. cacao husk aqueous extracts (TCE). Results A significantly higher glucose dialysis retardation index (GDRI) was shown by 10% TCE than the rest of the concentrations (1%, 3%, 5%, 7%) (P<0.05), and its activity is comparable with 5% Metformin (positive control) after 30 min, 60 min, 120 min and 180 min of incubation. The 7% TCE also showed significantly higher GDRI than the 5%, 3%, and 1% concentrations (P<0.05), and its activity is comparable with 5% Metformin after 60 min and 180 min of incubation. Moreover, 10% TCE exhibited a significantly higher glucose uptake percentage than the rest of the samples (P<0.05) and has activity comparable with 5% Metformin. The anti-inflammatory assay showed a significantly higher inhibition rate of 10% TCE than the rest of the concentrations (P<0.05), and its activity is comparable with 5% Diclofenac (positive control). The cytotoxicity assay showed that the percentage mortality of brine shrimps after 24 h of exposure to the different TCE samples is less than 50%. Conclusion This study concludes that T. cacao husk aqueous extract has potential antidiabetic and anti-inflammatory properties without being toxic to cells.

Influence of Microplastics on the Growth and the Intestinal Microbiota Composition of Brine Shrimp

Microplastics (MPs) are ubiquitous in the aquatic environment and can be frequently ingested by zooplankton, leading to various effects. Brine shrimp (Artemia parthenogenetica) has an important role in the energy flow through trophic levels in different seawater systems. In this work, the influence of polyethylene (PE) and polystyrene (PS) MPs on the growth of brine shrimp and corresponding changes of gut microbiota were investigated. Our results showed that the MPs remarkably reduced the growth rate of brine shrimp, and the two types of MPs have different impacts. The average body length of brine shrimps was reduced by 17.92 and 14.95% in the PE group and PS group, respectively. MPs are mainly found in the intestine, and their exposure evidently affects the gut microbiota. By using 16S rRNA gene high-throughput sequencing, 32 phyla of bacteria were detected in the intestine, and the microbiome consisted mainly of Proteobacteria, Firmicutes, and Actinobacteria. MPs’ exposure significantly increased the gut microbial diversity. For the PE group, the proportion of Actinobacteria and Bacteroidetes increased by 45.26 and 2.73%, respectively. For the PS group, it was 54.95 and 1.27%, respectively. According to the analysis on genus level, the proportions of Ponticoccus, Seohaeicola, Polycyclovorans, and Methylophaga decreased by 46.38, 1.24, 1.07, and 2.66%, respectively, for the PE group and 57.87, 1.43, 0.88, and 2.24%, respectively, for the PS group. In contrast, the proportions of Stappia, Microbacterium, and Dietzia increased by 1.12, 23.27, and 11.59%, respectively, for the PE group, and 1.09, 3.79, and 42.96%, respectively, for the PS group. These experimental results demonstrated that the ingestion of MPs by brine shrimp can alter the composition of the gut microbiota and lead to a slow growth rate. This study provides preliminary data support for understanding the biotoxicity of MPs to invertebrate zooplankton and is conducive to the further risk assessment of MP exposure.

Microalgal Diet Influences the Nutritive Quality and Reproductive Investment of the Cyclopoid Copepod Paracyclopina nana

Copepods represent an interesting alternative or a complement live food to brine shrimps and rotifers commonly used in aquaculture. They constitute the natural prey of many fish species and therefore do not require a potential nutritional enrichment. But an optimization of the microalgal diets used to feed copepods is essential to improve their mass culture. This study examined the effects of seven microalgal diets, namely single-species diets of Rhodomonas salina (R), Tisochrysis lutea (T), and Pavlova lutheri (=Diacronema lutheri) (P), two-species diets (R + T, T + P, and R + P), and a three-species diet (R + T + P), on the fatty acid and monosaccharide composition of the cyclopoid copepod Paracyclopina nana as well as its reproductive investment. Experiments were run during 15 days in 10-L beakers; starting with nauplii collected from a large 300-L batch culture. Copepods fatty acid contents were studied, particularly the relative amounts of docosahexaenoic acid (DHA) and eicosa-pentaenoic acid (EPA). The R + T, R, and T diets induced the highest total fatty acid amount in copepods. R + T and R also generated the lowest DHA/EPA ratios in copepods due to high EPA contents. The highest value of total monosaccharides was found in copepods fed with R + T + P. Diets R + T and R induced the greatest prosome volumes and clutch volumes in ovigerous females. Both prosome volume and clutch volume in P. nana ovigerous females were correlated to the individual EPA amount. The results demonstrated that all diets including R. salina enhanced the productivity of P. nana in mass culture, particularly when combined with T. lutea. R. salina, and T. lutea induced complementary fatty acid and monosaccharide profiles, confirming that R + T represents the best microalgae combination for productive culture of P. nana. Conversely, P. lutheri did not enhance the nutritional profile nor the fecundity of P. nana in the culture. This study is the first to demonstrate that R. salina is a suitable microalga for productive mass culture of P. nana for use as live food in aquaculture.

Explaining Variation in Abundance and Species Diversity of Avian Cestodes in Brine Shrimps in the Salar de Atacama and Other Chilean Wetlands

Further biogeographical studies of parasites are vital to improve our understanding of biodiversity distribution and predict the impacts of global change. Hypersaline lakes are good laboratories to investigate the avian cestode abundance and species diversity given the abundance of hosts (waterbirds and Artemia) and their broad latitudinal distribution. We analysed cestode infection in brine shrimp Artemia franciscana in northern (Atacama) and central Chile and compared them to results from A. persimilis in southern Chile (Patagonia). Thus, we covered a broad latitudinal gradient from 23° to 53° S. Five cestode taxa including two species of the genus Flamingolepis, Gynandrotaenia stammeri, Eurycestus avoceti, and Fuhrmannolepis averini were recorded from A. franciscana in Atacama lagoons (prevalence = 4.1%). In contrast, no cestode infection was detected in central Chile, likely because they are temporary wetlands. Parasites of flamingos and shorebirds were associated with Atacama lagoons (arid and higher salinity), while Confluaria podicipina and Fimbriarioides sp. (parasites of grebes and ducks, respectively) were dominant in Patagonian lagoons (sub-antarctic and of lower salinity). These differences mirror changes in the relative abundance of the respective final hosts. The flamingo parasite Flamingolepis sp. 1 was the most prevalent and abundant cestode in Atacama, where it was recorded only in autumn. Seasonality and habitat effects (especially abundance and phenology of different bird species) appear to override any latitudinal trends in the prevalence, diversity, and distribution of cestodes. Cestode prevalence was higher in larger wetlands but was not related to the sex of either intermediate host. We recorded a greater taxonomic richness at the cestode family level in Atacama, but a greater dominance of a single family of avian hosts (the flamingos). Ours is the first spatio–temporal study of Artemia cestodes at local and regional scales in the southern hemisphere.

The origin of asexual brine shrimps

Determining how and how often asexual lineages emerge within sexual species is central to our understanding of sex-asex transitions and the long-term maintenance of sex. Asexuality can arise "by transmission" from an existing asexual lineage to a new one, through different types of crosses. The occurrence of these crosses, cryptic sex, variation in ploidy and recombination within asexuals greatly complicates the study of sex-asex transitions, as they preclude the use of standard phylogenetic methods and genetic distance metrics. In this study we show how to overcome these challenges by developing new approaches to investigate the origin of the various asexual lineages of the brine shrimp Artemia parthenogenetica. We use a large sample of asexuals, including all known polyploids, and their sexual relatives. We combine flow cytometry with mitochondrial and nuclear DNA data. We develop new genetic distance measures and methods to compare various scenarios describing the origin of the different lineages. We find that all diploid and polyploid A. parthenogenetica likely arose within the last 80,000 years through successive and nested hybridization events that involved backcrosses with different sexual species. All A. parthenogenetica have the same common ancestor and therefore likely carry the same asexuality gene(s) and reproduce by automixis. These findings radically change our view of sex-asex transitions in this group, and show the importance of considering asexuality "by transmission" scenarios. The methods developed are applicable to many other asexual taxa.

In-vitro Cytotoxicity Evaluation of Green Synthesized Gold Nanoparticles and Its Indigenous Mouthwash

The aim of this study was to evaluate the cytotoxicity of the prepared Gold Nanoparticles from Triphala Plant extract and of the indigenous mouthwash prepared from these Triphala based gold nanoparticles (AuNP’s) using Artemia salina test. Its objective was to assess whether the prepared mouthwash was safe and biocompatible to use as an alternative to commercial mouthwashes in orthodontic patients to reduce the plaque load around brackets and bands as an adjuvant to tooth brushing. 15 g of brine shrimps was hatched in salt solution after incubating them for 24 – h. Prepared AuNP’s at concentrations 0µL (microliter), 5µL, 10µL, 20µL, 30µL, 50µL were added using a micropipette in one of the microtiter plates and mouthwash prepared from these AuNP’s were added at concentrations 0µL, 10µL, 20µL, 30µL, 40µL, 50µL in another microtiter plate. 10 Hatched nauplii (brine shrimps) were added in each of these microtiter plates and incubated for 24 – h. All nauplii were alive at the end of 24 – h in the microtiter plate containing AuNP’s. At concentrations 0µL, 10µL, 20µL, 30µL nauplii were alive and at 40µL, 50µL concentrations no nauplii were alive at the end of 24 – h in the microtiter plate containing mouthwash. Triphala mediated AuNP’s showed no toxic effect on the brine shrimps. AuNP’s based mouthwash showed excellent compatibility at lower concentrations. Mild toxic effects were elicited at higher concentrations. Hence, AuNP’s could be used to prepare mouthwashes at 20- 30 µL concentrations.

Evaluation of Indonesian mangrove Xylocarpus granatum leaves ethyl acetate extract as potential anticancer drug

Local Xylocarpus granatum leaves were extracted by ethyl acetate solvent and characterized by TLC fingerprinting and 2D 1H NMR spectroscopy to contain phenolic compounds as well as several organic and amino acids as metabolic byproducts, such as succinic acid and acetic acid. Traces of flavonoids and other non-categorized phenolic compounds exhibited intermediate antioxidant activity (antioxidant IC50 84.93 ppm) as well as anticancer activity against HeLa, T47D, and HT-29 cell lines; which the latter being most effective against HT-29 with Fraction 5 contained the strongest activity (anticancer IC50 23.12 ppm). Extracts also behaved as a natural growth factor and nonlethal towards brine shrimps as well as human adipose-derived stem cell hADSC due to antioxidative properties. A stability test was performed to examine how storage conditions factored in bioactivity and phytochemical structure. Extracts were compared with several studies about X. granatum leaves extracts to evaluate how ethnogeography and ecosystem factored on biologically active compounds. Further research on anticancer or antioxidant mechanism on cancer cells is needed to determine whether the extract is suitable as a candidate for an anticancer drug.

Stability and Toxicity Test of Angkak Pigment Powder from Sago Hampas- Rice Flour Substrate as Natural Dyes

Sago hampas is waste from processing sago starch. Sago hampas is generally thrown away without any further treatment. Sago hampas contain nutrients that can be used as a substrate for fermentation of angkak. The study aims to determine the stability and toxicity of angkak pigment powder from sago hampas-rice flour substrate. The study used exploratory research design through experiments in the laboratory. This study used the UV-vis spectrophotometer method in observing the stability of the Angkak powder pigment and the brine shrimps method of angkak pigment powder toxicity test. The results showed that the level of solubility of angkak pigment powder will increase at higher temperatures. Stability of angkak pigment powder tends to decrease with longer heating, the higher of heating temperature and the longer of irradiation. Angkak pigment powder are more stable at neutral and alkaline pH compared with acidic pH. And it is not toxic to experimental animals with LC50 value of angkak pigment powder of 2,897.05 ppm. The conclusion of this study is that temperature affects the intensity of the angkak pigment. Angkak is unstable along with heating time, heating temperature and longer of irradiation.