Description of five new Luticola D.G.Mann (Bacillariophyta, Diadesmidaceae) species from Indonesia with comments on the morphological boundaries of the genus.

During a survey of the Indonesian diatoms, five Luticola D.G.Mann taxa that could not be identified, based on the available literature were discovered. Based on light microscopy, scanning electron microscope observations and comparisons with similar taxa, all of them are described as new species. All taxa were found on mosses growing on tree trunks and concrete on the islands of Banda Besar and Seram and from spring on Java Island. Luticolainsularissp. nov. is most similar to L.aequatorialis and L.simplex, but it can easily be distinguished from both taxa, based on the lower striae density, the narrower valves and the well-developed silica ridges on the valve face/mantle junction. Luticolabandanensissp. nov. resembles L.frequentissima, but they can be easily distinguished, based on their valve widths and the direction of the grooves located on the distal and proximal raphe endings. Luticolaellipticasp. nov. is most similar to L.sparsipunctata, L.tenuis and L.bryophila. Amongst all the species compared, L.ellipticasp. nov. is the only one with a highly asymmetrical central area, with the isolated pore located on the wider side. Luticolamalukuanasp. nov. shares similarities with L.dismutica and L.areolata, but it has a notably higher stria density. From L.areolata, it can also be separated by the morphology of striae and the lack of ghost areolae in the central area. Luticolapoliporeasp. nov. is unique in the whole genus due to the presence of multiple isolated pores.

Analyze the toxicities of benzalkonium chloride as a COVID-19 disinfectant in physiological goldfish (Carassius auratus).

Background and Aims: Coronavirus disease-2019 (COVID-19) impacts increasing the use of disinfectants (benzalkonium chloride), which indirectly accumulate in water. The disinfectant accumulation in waters has been studied, but there has been no study of its impact on aquatic commodities, especially fish with a high sensitivity, one of which is goldfish (Carassius auratus). Benzalkonium chloride can potentially affect several body proteins, including the cytoskeleton, nervous and endocrine systems, and fish physiology. This study aimed to determine the impact of benzalkonium chloride as a disinfectant on the level of color brightness, growth, gill histopathology, and mortality in goldfish. This investigation provides input into the impact of using disinfectants to prevent COVID-19 on aquatic commodities. Materials and Methods: This study utilized goldfish specimens sourced from Tulungagung, East Java, Indonesia. The experiment involved different concentration levels of benzalkonium chloride: (T1) 0 mg/L, (T2) 0.03 mg/L, (T3) 0.06 mg/L, (T4) 0.09 mg/L, and (T5) 0.12 mg/L. The research data were subjected to an analysis of variance for analysis. In cases where significant differences were observed, Duncan's test was conducted for color brightness, growth, and mortality data. Furthermore, if the gill histopathological data yielded significant differences, additional tests were applied (Kruskal-Wallis and Mann-Whitney test). Results: The findings of this study demonstrated significant differences (p < 0.05) in the level of color brightness, growth, gill histopathology, and mortality in goldfish in response to varying concentrations of benzalkonium chloride. The relationship between the length and weight of the goldfish was analyzed using regression coefficients (b values), which were determined as 4.86, -0.04, -0.2, 0.8, and -0.07, respectively. Notably, the brightness level in the T2 group exhibited positive color results with a hue value of 11.55°, while optimal growth was observed in the T4 group, as evidenced by b value of 0.8. The gill histopathological data showed significant differences (p < 0.05). The scoring of histopathological damage in the goldfish gills ranged from 0 to 10, with higher scores indicating more severe damage. The highest total score of 10 was observed in the T5 group exposed to a concentration of 0.12 mg/L, resulting in an 85% mortality rate. This indicates that benzalkonium chloride, with its toxic compounds, can disrupt the respiratory system of fish and lead to death. Conclusion: The effects of benzalkonium chloride were evident even at a concentration of 0.03 mg/L. With increasing concentration, there was an increase in mortality rate, a decrease in growth, and a rise in histopathological damage to the gills. These findings highlight the negative impact of using conventional disinfectants on water and its organisms, emphasizing the need for further research on environmentally friendly alternatives.

The nanomolar affinity of C-phycocyanin from virtual screening of microalgal bioactive as potential ACE2 inhibitor for COVID-19 therapy.

The global pandemic of COVID-19 caused by SARS-CoV-2 has caused more than 400 million infections with more than 5.7 million deaths worldwide, and the number of validated therapies from natural products for treating coronavirus infections needs to be increased. Therefore, the virtual screening of bioactive compounds from natural products based on computational methods could be an interesting strategy. Among many sources of bioactive natural products, compounds from marine organisms, particularly microalgae and cyanobacteria, can be potential antiviral agents. The present study investigates bioactive antiviral compounds from microalgae and cyanobacteria as a potential inhibitor of SARS-CoV-2 by targeting Angiotensin-Converting Enzyme II (ACE2) using integrated in silico and in vitro approaches. Our in silico analysis demonstrates that C-Phycocyanin (CPC) can potentially inhibit the binding of ACE2 receptor and SARS-CoV-2 with the docking score of -9.7 kcal mol-1. This score is relatively more favorable than the native ligand on ACE2 receptor. Molecular dynamics simulation also reveals the stability interaction between both CPC and ACE2 receptor with a root mean square deviation (RMSD) value of 1.5 Å. Additionally, our in vitro analysis using the surface plasmon resonance (SPR) method shows that CPC has a high affinity for ACE2 with a binding affinity range from 5 to 125 µM, with KD 3.37 nM. This study could serve as a reference to design microalgae- or cyanobacteria-based antiviral drugs for prophylaxis in SARS-CoV-2 infections.

Distribution and morphology of the diatom genus Olifantiella Riaux-Gobin & Compère in Indonesian and Australian waters, including the description of O.gondwanensis sp. nov.

Samples from coastal tropical waters of Central Sulawesi, Bangka Island and Bawean Island in Indonesia and from the Great Barrier Reef at Fitzroy Island in Queensland, Australia were analysed for species composition of diatom assemblages with a focus on Olifantiella. Whereas samples from Fitzroy Island littoral in Australia retrieved only one species of Olifantiella, in Poso Bay, Indonesia, we observed at least six species. All established taxa were documented with light (LM) and scanning electron microscope (SEM) and principal component analysis (PCA) analysis was used to compare the species, based on the basic valve parameters of length, width, length to width ratio and striae density. A new species of the genus Olifantiella, O.gondwanensis is described from Australia. In addition, we showed the distinct nature of O.pilosellavar.rhizophorae permitting to species status. Particular attention is placed on girdle bands in this genus.

Marennine, promising blue pigments from a widespread Haslea diatom species complex.

In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting. A method to extract and purify marennine has been developed, but its chemical structure could hitherto not be resolved. For decades, H. ostrearia was the only organism known to produce marennine, and can be found worldwide. Our knowledge about H. ostrearia-like diatom biodiversity has recently been extended with the discovery of several new species of blue diatoms, the recently described H. karadagensis, H. silbo sp. inedit. and H. provincialis sp. inedit. These blue diatoms produce different marennine-like pigments, which belong to the same chemical family and present similar biological activities. Aside from being a potential source of natural blue pigments, H. ostrearia-like diatoms thus present a commercial potential for aquaculture, cosmetics, food and health industries.