Filamentous Species Research Articles

Temporal variation of 2-MIB and geosmin production by Pseudanabaena galeata and Phormidium ambiguum exposed to high-intensity light.

This study demonstrated the temporal variation of 2-methylisoborneol (2-MIB) and geosmin (GSM) production of two filamentous cyanobacteria species Pseudanabaena galeata (NIES-512; planktonic) and Phormidium ambiguum (NIES-2119; benthic) exposed to high light intensity (950-1000 μmol m-2 s-1 photosynthetically active radiation). The production of 2-MIB and GSM was quantified together with oxidative stress, chlorophyll content, and cellular protein content. The relative chlorophyll bleaching and cell degradations were compared through microscopic images. The 2-MIB production of P.galeata increased by over 42 ± 17% on the second day of exposure and remained leveled through the exposure period. P.ambiguum showed a continuous increase of 2-MIB until the 10th day, recording a 95 ± 4% increment. The GSM production was elevated until the fourth day of exposure by 46 ± 10% for P.galeata and by 74 ± 21% on the second day for P.ambiguum and reduced with prolonged exposure for both species. The chlorophyll content of P.galeata was reduced by 62 ± 7% on the second day, and that of P.ambiguum was reduced by 52 ± 9% on the fourth day and remained low. Protein and H2 O2 contents of both species were changed inconsistently. Exposure to high-intensity light can photobleach and deteriorate cells of both species, but elevations in odorous compounds can be expected.

Effect of Growth of Filamentous Algae on the Thallus Surface of Kappaphycus alvarezii (Doty) L.M.Liao (Rhodophyta)

Filamentous algae usually form dense or sparse masses that float freely or attach to other plants, rocks, or other hard substrates. Many filamentous algae attach to <i>Kappaphycus alvarezii</i> which is cultivated by farmers in the tropics. This study explained the effect of filamentous algae attachment on the morphology and growth of <i>K. alvarezii</i>. This research was conducted in one of the cultivation locations on the coast of Tanjung Tiram, southeast Sulawesi Province, Indonesia. This study used a vertical net to cultivate <i>K. alvarezii</i> thallus samples. Vertical nets are used to protect <i>K. alvarezii</i> from fish pests and attached algae. We analyze the attachment rate of filamentous algae about the morphology and growth of <i>K. alvarezii</i> thallus within 40 days. The results showed two dominant filamentous algae species, Elachista flaccida and Chaetomorpha crassa. The density of E. flaccida occurred on day 10, with a density level reaching 12 individuals/m<sup>2</sup> and increasing on day 20 to 45 individuals/m<sup>2</sup>. Chaetomorpha crassa species also appeared at 2.24 g/m<sup>2</sup> on day 20, decreased to 0.63 g/m<sup>2</sup> on day 30, and disappeared on day 40. The torn surface thallus was seen to occur on day 2.324 mm<sup>2</sup> on day ten and decreased by 104 mm<sup>2</sup> on day 20. Attachment of filamentous algae slightly impacted the growth of <i>K. alvarezii</i> thallus, although the correlation analysis did not show a significant effect. Another correlation analysis explained no significant correlation between multiple attachments of filamentous algae and torn surface thallus of <i>K. alvarezii</i>.

Metabolomics of bacterial-fungal pairwise interactions reveal conserved molecular mechanisms.

Bacterial-fungal interactions (BFIs) can shape the structure of microbial communities, but the small molecules mediating these BFIs are often understudied. We explored various optimization steps for our microbial culture and chemical extraction protocols for bacterial-fungal co-cultures, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that metabolomic profiles are mainly comprised of fungi derived features, indicating that fungi are the key contributors to small molecules in BFIs. LC-inductively coupled plasma MS (LC-ICP-MS) and MS/MS based dereplication using database searching revealed the presence of several known fungal specialized metabolites and structurally related analogues in these extracts, including siderophores such as desferrichrome, desferricoprogen, and palmitoylcoprogen. Among these analogues, a novel putative coprogen analogue possessing a terminal carboxylic acid motif was identified from Scopulariopsis sp. JB370, a common cheese rind fungus, and its structure was elucidated via MS/MS fragmentation. Based on these findings, filamentous fungal species appear to be capable of producing multiple siderophores with potentially different biological roles (i.e. various affinities for different forms of iron). These findings highlight that fungal species are important contributors to microbiomes via their production of abundant specialized metabolites and that elucidating their role in complex communities should continue to be a priority.

Zcf24, a zinc-finger transcription factor, is required for lactate catabolism and inhibits commensalism in Candida albicans.

Candida albicans is a normal resident of humans and also a prevalent fungal pathogen. Lactate, a nonfermentative carbon source available in numerous anatomical niches, can be used by C. albicans as a carbon source. However, the key regulator(s) involved in this process remain unknown. Here, through a genetic screen, we report the identification of a transcription factor Zcf24 that is specifically required for lactate utilization in C. albicans. Zcf24 is responsible for the induction of CYB2, a gene encoding lactate dehydrogenase that is essential for lactate catabolism, in response to lactate. Chromatin immunoprecipitation showed a significantly higher signal of Zcf24 on the CYB2 promoter in lactate-grown cells than that in glucose-grown cells. Genome-wide transcription profiling indicates that, in addition to CYB2, Zcf24 regulates genes involved in the β-oxidation of fatty acids, iron transport, and drug transport. Surprisingly, deleting ZCF24 confers enhanced commensal fitness. This could be attributed to Crz1-activated β-glucan masking in the zcf24 mutant. The orthologs of Zcf24 are distributed in species most closely to C. albicans and some filamentous fungal species. Altogether, Zcf24 is the first transcription factor identified to date that regulates lactate catabolism in C. albicans and it is also involved in the regulation of commensalism.

Two different morphotypes of freshwater Cladophora surera (Cladophorales, Chlorophyta) produce similar sulfated cell wall polysaccharides

The Cladophoraceae (Cladophorales) includes branched (Cladophora) and unbranched (Chaetomorpha and Rhizoclonium) filamentous species, living in marine and freshwater environments. Species-level taxonomy is impeded by considerable morphological plasticity, related to environmental conditions, and switches between branched and unbranched morphologies have been reported within species. In this work, it was shown that Cladophora surera, a species widely distributed in streams in the Pampa Plains of Argentina, appears in two different morphotypes, branched and unbranched filaments. Phylogenetic analysis indicated that they correspond to the same species. The presence of these morphotypes could not be related with season or water flow. Moreover, under the same culture conditions it was possible to develop the branched morphotype from the unbranched one. The general structure of sulfated galactoxyloarabinans biosynthesized by the branched morphotype of this alga were studied previously. In this work, these sulfated 4-linked pyranosic arabinans were studied in relation to morphotype and season. It was shown that differences in structure of the water-soluble polysaccharides between samples could not be related to the morphotype but depend on the season. A detailed study by principal components analysis (PCA) of variables related with the main structural features showed clear differences between sulfated polysaccharides extracted from algae collected in spring, compared to those collected in other seasons. Structural analysis by chemical and spectroscopic methods of these sulfated arabinans collected in the different seasons are reported and discussed.

Complementary Strategies to Unlock Biosynthesis Gene Clusters Encoding Secondary Metabolites in the Filamentous Fungus Podospora anserina.

The coprophilous ascomycete Podospora anserina is known to have a high potential to synthesize a wide array of secondary metabolites (SMs). However, to date, the characterization of SMs in this species, as in other filamentous fungal species, is far less than expected by the functional prediction through genome mining, likely due to the inactivity of most SMs biosynthesis gene clusters (BGCs) under standard conditions. In this work, our main objective was to compare the global strategies usually used to deregulate SM gene clusters in P. anserina, including the variation of culture conditions and the modification of the chromatin state either by genetic manipulation or by chemical treatment, and to show the complementarity of the approaches between them. In this way, we showed that the metabolomics-driven comparative analysis unveils the unexpected diversity of metabolic changes in P. anserina and that the integrated strategies have a mutual complementary effect on the expression of the fungal metabolome. Then, our results demonstrate that metabolite production is significantly influenced by varied cultivation states and epigenetic modifications. We believe that the strategy described in this study will facilitate the discovery of fungal metabolites of interest and will improve the ability to prioritize the production of specific fungal SMs with an optimized treatment.

Upstream Regulation of Development and Secondary Metabolism in Aspergillus Species.

In filamentous fungal Aspergillus species, growth, development, and secondary metabolism are genetically programmed biological processes, which require precise coordination of diverse signaling elements, transcription factors (TFs), upstream and downstream regulators, and biosynthetic genes. For the last few decades, regulatory roles of these controllers in asexual/sexual development and primary/secondary metabolism of Aspergillus species have been extensively studied. Among a wide spectrum of regulators, a handful of global regulators govern upstream regulation of development and metabolism by directly and/or indirectly affecting the expression of various genes including TFs. In this review, with the model fungus Aspergillus nidulans as the central figure, we summarize the most well-studied main upstream regulators and their regulatory roles. Specifically, we present key functions of heterotrimeric G proteins and G protein-coupled receptors in signal transduction), the velvet family proteins governing development and metabolism, LaeA as a global regulator of secondary metabolism, and NsdD, a key GATA-type TF, affecting development and secondary metabolism and provide a snapshot of overall upstream regulatory processes underlying growth, development, and metabolism in Aspergillus fungi.

Biocoagulation of Dried Algae Chlorella sp. and Pellets of Aspergillus Niger in Decontamination Process of Wastewater, as a Presumed Source of Biofuel.

The removal of microalgae represents a problematic part of the water decontamination process, in which most techniques are expensive and non-ecological. In the paper, we focus on the synergistic relationship between microscopic filamentous fungi and algal culture. In the process of decontamination of a model sample containing ammonium ions, efficient biocoagulation, resp. co-pelletization of dried algae Chlorella sp. and Aspergillus niger sensu stricto are shown. The microscopic filamentous fungus species A. niger was added to a culture of an algal suspension of Chlorella sp., where the adhesion of the algal cells to the fungi subsequently occurred due to the electrostatic effect of the interaction, while the flocculation activity was approximately 70 to 80%. The algal cells adhered to the surface of the A. niger pellets, making them easily removable from the solution. The ability of filamentous fungi to capture organisms represents a great potential for the biological isolation of microalgae (biocoagulation) from production solutions because microalgae are considered to be a promising renewable source of oil and fermentables for bioenergy. This form of algae removal, or its harvesting, also represents a great low-cost method for collecting algae not only as a way of removing unnecessary material but also for the purpose of producing biofuels. Algae are a robust bioabsorbent for absorbing lipids from the environment, which after treatment can be used as a component of biodiesel. Chemical analyses also presented potential ecological innovation in the area of biofuel production. Energy-efficient and eco-friendly harvesting techniques are crucial to improving the economic viability of algal biofuel production.

Relationship between Fucus coverage and algal diversity in the northern Baltic Sea

The canopy-forming brown macroalgae Fucus vesiculosus and Fucus radicans (Fucus) are the largest habitat-building species on rocky shores of the northern Baltic Sea. While their role on the diversity of invertebrate fauna is well documented, there is little information on their importance for the diversity of associated macroalgal species. We used comprehensive mapping data from the Finnish marine area (divided into four sea areas) to test the relationship between Fucus coverage and algal biodiversity (number of taxonomic units, Shannon-Wiener diversity index H′ and Pielou's evenness J'). To account for environmental variation, depth, wave exposure, Secchi depth and salinity were included as covariates. Examination of the algal communities highlighted a similar pool of taxonomic units across sea areas in shallow (0–4 m) rocky shores, with the two filamentous algal species Pylaiella littoralis and Ectocarpus siliculosus combined as one unit being the most common taxon. The Shannon-Wiener diversity index was highest in sites with Fucus coverage between 25% and 75%, while evenness increased with Fucus coverage. We did not detect any effects of Fucus coverage on the number of taxonomic units, which was rather affected by environmental parameters (depth, Secchi depth and salinity). The results show that Fucus, depending on its coverage, both competes with and facilitates the macroalgal community. Based on extensive data, we show how Fucus coverage relates to the diversity of the surrounding algal communities, further improving our understanding of factors that control biodiversity on shallow rocky shores in the northern Baltic Sea.

Deciphering interactions between the marine dinoflagellate Prorocentrum lima and the fungus Aspergillus pseudoglaucus.

The comprehension of microbial interactions is one of the key challenges in marine microbial ecology. This study focused on exploring chemical interactions between the toxic dinoflagellate Prorocentrum lima and a filamentous fungal species, Aspergillus pseudoglaucus, which has been isolated from the microalgal culture. Such interspecies interactions are expected to occur even though they were rarely studied. Here, a co-culture system was designed in a dedicated microscale marine-like condition. This system allowed to explore microalgal-fungal physical and metabolic interactions in presence and absence of the bacterial consortium. Microscopic observation showed an unusual physical contact between the fungal mycelium and dinoflagellate cells. To delineate specialized metabolome alterations during microalgal-fungal co-culture metabolomes were monitored by high-performance liquid chromatography coupled to high-resolution mass spectrometry. In-depth multivariate statistical analysis using dedicated approaches highlighted (1) the metabolic alterations associated with microalgal-fungal co-culture, and (2) the impact of associated bacteria in microalgal metabolome response to fungal interaction. Unfortunately, only a very low number of highlighted features were fully characterized. However, an up-regulation of the dinoflagellate toxins okadaic acid and dinophysistoxin 1 was observed during co-culture in supernatants. Such results highlight the importance to consider microalgal-fungal interactions in the study of parameters regulating toxin production.

Planktothrix agardhii versus Planktothrix rubescens: Separation of Ecological Niches and Consequences of Cyanobacterial Dominance in Freshwater.

Cyanobacteria dominate lakes under diverse trophic conditions. Of these, two harmful filamentous cyanobacterial species, namely Planktothrix agardhii and P. rubescens, occupy completely different ecological niches in which they can form dense populations. In the present study, we investigated the effects of environmental conditions on the growth and vertical distribution of these species in lakes of different trophic statuses. Moreover, we underscored certain inconveniences in the assessment of the ecological status of lakes according to the European Union Water Framework Directive. The highest biomass of P. agardhii was recorded in eutrophic lake at a depth of 0.5-1 m, under high light intensity. Meanwhile, the highest biomass of P. rubescens, at which the deep chlorophyll maximum was recorded, was observed in mesotrophic lakes at a depth of 11-12 m, often below the euphotic zone under very low light intensity. P. rubescens, but not P. agardhii, exerted a strong allelopathic effect on the diversity and biomass of phytoplankton. Moreover, both species utilised different dissolved nitrogen fractions for their growth; specifically, P. agardhii used ammonium nitrogen, whilst P. rubescens used nitrate nitrogen. Furthermore, dissolved phosphorus produced a potentially limiting effect on P. rubescens growth. Overall, the tested Polish PMPL, German PSI, and Estonian phytoplankton indices were indeed useful in the assessment of the ecological status of lakes, albeit limited to the eutrophic lake with a high biomass of cyanobacteria (P. agardhii) in the upper water layers. However, problems arose in the proper assessment of lakes with a high biomass of cyanobacteria (P. rubescens) with a deep chlorophyll maximum outside the range of the euphotic zone. In such cases, two of the tested indices, namely the Polish and German indices, allowed sample collection from the euphotic layers, which significantly affected the number of samples included in the calculation. Consequently, the correct calculation of the ecological status of the lake was uncertain. Only the Estonian index allowed for a sample collection from two to three thermal layers of water, including the bloom layer of P. rubescens. Hence, the Estonian index offered the best fit for calculations.

Novel Assay for Attached Filamentous Algae Productivity and Nutrient Removal

Filamentous algae nutrient scrubbers (FANS) have demonstrated potential for cost-effective and sustainable nutrient bioremediation of a wide range of wastewaters. Typically, FANS are seeded with a mixed assemblage of algae species, however, growing a monoculture of one species on FANS could facilitate biomass use by providing a more consistent and high-quality substrate for end-product applications. To date, a standardised bioassay to assess the productivity and nutrient removal of filamentous algae attached to a bottom substrate (that could help identify promising species for FANS monoculture) has not been developed. Therefore, we developed a microscale filamentous algae nutrient scrubber (µFANS) and a protocol to establish monocultures of freshwater filamentous algae to compare performance in terms of attachment capability, nutrient removal and biomass production. Four common filamentous algae species (Cladophora sp., Oedogonium sp., Rhizoclonium sp. and Spirogyra sp.) were seeded by evenly distributing and rubbing the biomass onto µFANS textured liner to “hook” algal filaments, providing initial physical attachment. Within 14 days, a “lawn” of the seeded algae had established and the “hooked” biomass had attached biologically. Depending on species, biological attachment resulted from either holdfast development from filaments that grew from settled zoospores, growth of rhizoids or adhesion of filament fragments to mucilage. Biomass productivity of each species ranged from 2.2 to 5.3 g DW m−2 day−1 while nutrient removal rates ranged from 8.8 to 28.4 mg NO3 g−1 DW day−1 and 2.2 to 8.1 mg PO4 g−1 DW day−1. Oedogonium sp. was the best performing species overall, with the strongest holdfast attachment, high biomass productivity (mean 4.2 g DW m−2 day−1) and high nutrient removal rates (mean 21.8 mg NO3 g−1 DW day−1; 5.6 mg PO4 g−1 DW day−1).

Applied Tests to Select the Most Suitable Fungal Strain for the Recovery of Critical Raw Materials from Electronic Waste Powder

Electrical and electronic wastes (WEEEs) are a potential source of raw materials. The main challenge for scientists is to set up a reliable and eco-friendly process to recycle raw materials and precious elements from WEEEs. Today, we know that fungi could play an active role in green technologies aimed at recycling valuable elements. The bioaccumulation mechanism and bioleaching activity of filamentous fungal species have already been exploited fruitfully in extraction processes. However, not all fungal strains possess the same characteristics, and it is crucial to choose the right strains to use. In this work, we show a method to assess the precious elements’ recovery efficiency from WEEE using fungal strains. A CAS agar screening test for siderophore detection was carried out with three strains. The following plate accumulation test performed on a medium added with 120 ppm of electronic waste powder highlighted the differences in accumulation capability, growth rate, and biomass production. Among the elements in tested waste, yttrium, copper, and palladium show the highest bioconcentration factor. The results confirm the biotechnological potential of fungi to recover valuable elements at the bench scale, highlighting the importance of effective screening tests to assess the most efficient strain for each kind of waste.

Evaluation on the Zn2+ ion adsorption capacity in water of Spirulina platensis biomaterial

Due to its rising accumulation in the food chain and ongoing presence in ecosystems, metal contamination has piqued the curiosity of experts from all over the world. Environmentally hazardous heavy metal removal is being pursued utilizing a variety of techniques, such as ion exchange and precipitation, as well as chemical oxidation or reduction, electrochemistry, and filtration. However, these methods require high investment and operating costs, and generate toxic sludge. Spirulina platensis, a filamentous cyanobacteria species, has been reported as a potential bioadsorbent for the removal of some heavy metals from industrial wastewater. In this study, the bioadsorption of Zn2+ ions in an assumed aqueous solution by the dry biomass of S. platensis TH was investigated. The Zn2+ ion adsorption of biomaterials was evaluated under different conditions, including pH, contact time, temperature, and adsorbent mass. The optimal Zn2+ ion removal efficiency reached 90.32 ± 0.29% at Zn2+ ion concentration of 100 mg/L, pH 5.0, a temperature of 26oC, and a dry biomass dose of 1.5 g/L for 90 min. Langmuir and Freundlich's isothermal models were used to describe the adsorption isotherm of Zn2+ ions on S. platensis TH. Equilibrium data fitted well with the Langmuir model as well as the Freundlich model, with a maximum adsorption capacity of 34.56 mg Zn2+/g S. platensis TH under the reaction conditions of 1.5 g/L biomass dosage, the contact time of 90 min, pH 5.0, at 26oC. Research results have shown that S. platensis TH biomass is an easy, readily available, low-cost adsorbent and has a high bioadsorption capacity. Therefore, it can be treated as a bioadsorbent in the treatment of wastewater containing Zn2+ ions. This process is not only environmentally friendly but also versatile as an alternative to conventional heavy metal treatment methods.

Online Biomass Monitoring Enables Characterization of the Growth Pattern of Aspergillus fumigatus in Liquid Shake Conditions.

Numerous filamentous fungal species are extensively studied due to their role as model organisms, workhorses in biotechnology, or as pathogens for plants, animals, and humans. Growth studies are mainly carried out on solid media. However, studies concerning gene expression, biochemistry, or metabolism are carried out usually in liquid shake conditions, which do not correspond to the growth pattern on solid media. The reason for this practice is the problem of on-line growth monitoring of filamentous fungal species, which usually form pellets in liquid shake cultures. Here, we compared the time-consuming and tedious process of dry-weight determination of the mold Aspergillus fumigatus with online monitoring of biomass in liquid shake culture by the parallelizable CGQ (“cell growth quantifier”), which implements dynamic biomass determination by backscattered light measurement. The results revealed a strong correlation of CGQ-mediated growth monitoring and classical biomass measurement of A. fumigatus grown over a time course. Moreover, CGQ-mediated growth monitoring displayed the difference in growth of A. fumigatus in response to the limitation of iron or nitrogen as well as the growth defects of previously reported mutant strains (ΔhapX, ΔsrbA). Furthermore, the frequently used wild-type strain Af293 showed largely decreased and delayed growth in liquid shake cultures compared to other strains (AfS77, A1160p+, AfS35). Taken together, the CGQ allows for robust, automated biomass monitoring of A. fumigatus during liquid shake conditions, which largely facilitates the characterization of the growth pattern of filamentous fungal species.

P046 Local adaptation to antifungal compounds in the model organism Neurospora crassa

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM The domestication of Neurospora crassa has been a major driver of the fields in fungal molecular and cell biology. Not only this filamentous species enjoys modest nutritional requirements and grows swiftly in the laboratory, but also its genome is considerably well annotated, and a near-complete deletion strain collection is available for functional analyses. Furthermore, decades of research with N. crassa have been accompanied by the accrual of wild isolates from different points of the globe, which are an invaluable tool to study local adaptation. Using a panel of antifungal compounds, we found that drug resistance is naturally heterogeneous in wild populations of N. crassa, and chromosomal mapping of the causal loci is underway to unveil the genetic basis of the observed natural diversity. Furthermore, we are interested in the regulatory role played by two Zn2Cys6 transcription factors, CZT-1, and TAH-3, during fungal responses to various drugs. In summary, despite it being non-pathogenic, N. crassa presents many advantages as a model to study antifungal drug resistance. Since the paucity of valid molecular targets in the fungal cell has been hindering the discovery of new antifungal drugs, we consider that the identification and functional characterization of new genes and pathways involved in drug resistance may inform the adoption of new therapeutic schemes.

Antifungal Activity and Qualitative Phytochemical Analysis of Green alga Ulothrix sp.

The antifungal activity of the ethanolic hot extract of the green filamentous species Chlorophyta was evaluated in vitro at various doses (25, 50, and 100 mg/ml) and shown to be effective. Antifungal activity was performed by evaluating the percentage inhibition growth method against some fungus were obtained from the postgraduate laboratories in the Department of Biology - Faculty of Science / University of Mustansiriya (Aspergillus niger, Fusarium oxysporum, Penicillium sp. and Rhizoctonia solani ). As a result of the research, it was discovered that the hot ethanol extract of Ulothrix sp had the most significant effect (91.8 %) on Rhizoctonia solani growth inhibition at a concentration of 100 mg/ml and the minor effect (22.4 %) at a concentration of 25 mg/ml against Aspergillus niger growth inhibition. It was discovered by primary chemical analysis of active substances that alkaloids, Terpenes, Saponines, phenols, Flavones, Resins, Steroids, and tannins were present in hot ethanolic alga extract. Finally, the GC-mass analysis performed on Ulothrix sp extracts revealed a large number of antibacterial activity-producing substances. Because the current research shows that algae have antifungal activity, it has the potential to be developed as a new source of active chemicals for human and plant consumption in a variety of applications shortly. Keywords: Antifungal activity, Ulothrix, Active compounds,

Negative impacts of cleaning agent DEPTAL MCL® on activated sludge wastewater treatment system.

DEPTAL MCL® is a professional cleaning agent approved by the Portuguese Food Regulatory Authority and is used in agro-food industries, namely in fish canning industries in the north of Portugal. Its extensive use during cleaning procedures results in potential significant negative impacts on the performance of the downstream municipal wastewater treatment plant (WWTP). A lab-scale extended areation activated sludge wastewater treatment system, continuously fed by influent collected at a municipal WWTP, was used to assess the impact of a range of DEPTAL MCL® concentrations during 72 h. Despite distinct activated sludge community composition (due to its dynamic nature) and variations in real influent characteristics, a relevant impact was observed. DEPTAL MCL® effect was underscored through the use of a multivariate analysis using seventeen physicochemical operational factors and nineteen quantitative image analysis (QIA) parameters. DEPTAL MCL® exerted a severe negative impact on phosphorous (P-PO4) removal, total nitrogen (TN) removal and sludge volume index (SVI). With increasing DEPTAL MCL® concentrations, both P-PO4 and TN removal were affected and diminished proportionally. Moreover, several QIA parameters indicate defloculation when DEPTAL MCL® was present, in particular for intermediate size aggregates with significant impacts. Optical density of the effluent (Ode), displayed an increase of effluent turbidity. Percentage of area covered by small aggregates (%Areasml) was also significantly higher for the intermediate and higher DEPTAL MCL® concentrations tested. Principal component analysis exhibited 3 distinct ordenations: (i) control without addition of DEPTAL MCL®; (ii) addition of 0.03% and 0.06% and of (iii) 0.13 and 0.26% (v DEPTAL MCL®/v aeration tank). Canonical correspondence analysis (CCA) was used to correlate the physicochemical data, QIA and the filamentous bacteria species prevalence to DEPTAL MCL® concentration and incubation time. A time persistent DEPTAL MCL® effect was observed, underscoring the need of a pretreatment of wastewater containing this cleaning agent.

Kuwaitiella rubra gen. et sp. nov. (Bangiales, Rhodophyta), a new filamentous genus and species from the north‐western Indian Ocean

SUMMARYA new filamentous marine red alga, Kuwaitiella rubra gen. et sp. nov. (Bangiales, Rhodophyta), is described from Kuwait in the north‐western Arabian Gulf (also referred to as the Persian Gulf). It was found on a submerged fishing line. The intensively red upright thallus of up to 1 cm in length consists of cells containing a single stellate plastid. The thallus is initially uniseriate but becomes biseriate in its distal part upon transformation into globular reproductive cells, possibly archaeospores. The biseriate fertile part is the only morphological difference from other filamentous species of the Bangiales, in which this region is parenchymatous. In culture, bipolar asymmetric germination of the spores of Kuwaitiella led to a new generation of identical erect thalli, fixed to the substratum by colourless rhizoids. According to phylogenetic analyses of partial small subunit nuclear ribosomal DNA (18S) and of the plastid‐encoded ribulose‐1,5‐bisphosphate carboxylase/oxygenase large subunit (rbcL), the new species forms an additional lineage of the Bangiales, genetic similarity with other taxa being limited (maximum 91% in SSU and 90% in rbcL). It was no clear member of any known lineage of the Bangiales but was weakly associated with the filamentous species Minerva and Dione from New Zealand. In a SSU phylogeny, it formed a basal branch in the Bangiales and clustered with M. aenigmata and D. arcuata as sister clade to all other species of the order. In a rbcL phylogeny, it was part of a large polytomy of lineages, its closest relative being D. arcuata. Kuwaitiella forms the 8th lineage of filamentous Bangiales detected so far.

A diverse group of underappreciated zygnematophytes deserves in-depth exploration

ABSTRACT The conjugating green algae (Zygnematophyceae) are the closest relatives of land plants and hence are of great evolutionary interest. Besides the popular placoderm desmids and the filamentous species, there is an underappreciated diversity of unicellular zygnematophytes with a much “simpler” morphology and smooth cell walls – traditionally referred to as “saccoderm desmids”. These saccoderm desmids have a broad geographic distribution and are ecologically diverse. Many species inhabit terrestrial habitats such as dead wood, rock surfaces and glacial ice. Furthermore, several of the saccoderm genera have turned out to be highly polyphyletic and are typically poorly captured by environmental sequencing approaches. One of these genera is Mesotaenium Nägeli, with ~70 described species and infraspecific taxa united only by a relatively simple (plate- or ribbon-like) chloroplast structure. Here, we shed some light on these inconspicuous yet important members of the algal flora and present an updated rbcL gene phylogeny of the conjugating green algae, including several new lineages of Mesotaenium-like zygnematophytes. We depict the subtle morphological differences among these lineages and discuss our updated phylogeny in the light of ecology and cell biology. In addition, we review published knowledge on photoprotective strategies of zygnematophytes, the latest insights into their evolutionary innovations, and address some technical challenges in exploring this elusive group of microalgae. Some new observations of saccoderm desmids in undersampled habitats and of their microbial associates (e.g., parasites) point to interesting avenues for future research.