Polyphasic Approach and Potential Cyanotoxin Production by <i>Planktothrix</i> from the Río Grande de Comitán and Montebello Lakes National Park, Southern Mexico

Carmona Jiménez, Javier; Caro Borrero, Angela; Sánchez-Salas, Aída Isabel; Becerra-Absalón, Itzel; Cirés Gómez, Samuel; Quesada del Corral, Antonio; Perona Urizar, Elvira; Ortíz Suárez, David; Mazari-Hiriart, Marisa

doi:https://doi.org/10.1155/2024/9993635

International Journal of Microbiology

On this page

Abstract Introduction Methods Results Discussion Data Availability Conflicts of Interest Authors’ Contributions Acknowledgments References Copyright Related Articles

Research Article | Open Access

Volume 2024 | Article ID 9993635 | https://doi.org/10.1155/2024/9993635

Polyphasic Approach and Potential Cyanotoxin Production by Planktothrix from the Río Grande de Comitán and Montebello Lakes National Park, Southern Mexico

Javier Carmona Jiménez,¹Angela Caro Borrero,¹Aída Isabel Sánchez-Salas,^1,2Itzel Becerra-Absalón,³Samuel Cirés Gómez,⁴Antonio Quesada del Corral,⁴Elvira Perona Urizar,⁴David Ortíz Suárez,⁵and Marisa Mazari-Hiriart⁶

Academic Editor: Zhun Li

Received08 Jan 2024

Revised22 Mar 2024

Accepted28 Mar 2024

Published11 May 2024

Abstract

The development of anthropic activities during recent years has led to an increase in nutrient fluxes in the Río Grande de Comitán and Montebello Lakes National Park, Mexico. In turn, this has modified the dynamics of the biotic community, specifically favoring the presence of cyanobacteria tolerant to contamination. The continual and massive presence of Planktothrix species (spp.) in the system suggests a potential detrimental impact for economic issues and human health. In this study, we identify the morphological and molecular characteristics of Planktothrix populations from seven tropical (1,380–1,740 masl, 23.0–25.5°C) and calcareous lakes and two ponds from a water treatment plant. We also assess the ecological drivers that could be related to the presence of cyanotoxins in the system. The ecological preferences, morphology, 16S rRNA structure, and 16S-23S rRNA internal transcribed spacer found evidence for three species: P. agardhii distributed in neutral to slightly basic water (pH = 7.7–8.7), and P. spiroides and Planktothrix sp. in alkaline waters (pH = 9.1). The presence of the mcyE gene and its validation by liquid chromatography confirmed the presence of two microcystin variants (MC-RR and MC-LR) in at least three populations of P. agardhii. These microcystins put the health of the ecosystem and its inhabitants at risk, a condition that should be addressed and resolved with a water management and detoxification strategy in the basin.

1. Introduction

Cyanobacteria of the genus Planktothrix Anagnostidis et Komárek have been cited as abundant and frequent components in freshwater lake communities, known to form cyanobacterial blooms in temperate, tropical, and boreal climates throughout the world [1, 2]. The genus is characterized by trichomes that are solitary, rarely in small, irregular, and easily disintegrating fascicles (groups) (mainly in blooms), straight and isopolar, with aerotopes through the whole cell volume, and the end cells widely rounded or slightly narrowed. The systematic position of Planktothix species has been controversial due to morphological similarities and overlapping morphometric variation given the morphological plasticity within the genus [1, 3]. Molecular evidence using 16S rRNA sequences was a major contribution to delimiting and separating the Planktothix genus from Oscillatoria [4]. From morphological and molecular evidence, 21 species are currently recognized in the genus worldwide, but controversy still surrounds five species [5]. Suda et al. [3] established a new genus Planktothricoides, composed of the type species Planktothricoides raciborskii (originally Planktothrix raciborskii), as well as a new species Planktothrix pseudagardhii, two genera that are clearly delimited in genetic terms.

Planktothrix populations have the ability to produce secondary metabolites, including cyanotoxins, microcystins (MCs), a group of hepatotoxins whose ecological role is not well understood [6]. According to the World Health Organization (WHO) [7], prolonged exposure to MCs produces phosphatase inhibition, which, in humans, induces liver hypertrophy and tumor-promoting activity. For this reason, international regulations established that the permissible limit for MCs (estimated based on the most common variant) in drinking water must be less than 1 μgL⁻¹ [8]. Nutrient concentrations, as well as the parameters that promote the synthesis of MCs, are essential for assessing the potential presence of cyanobacterial blooms, particularly in Planktothrix populations [9–11]. For example, Gagała et al. [12] reported blooms of P. agardhii (Gomont) Anagnostidis et Komárek having concentrations of total nitrogen (TN) above 1.5 mg/dm³, total phosphorus (TP) greater than 0.1 mg/dm³, and a TN : TP ratio of 29 : 1, in temperatures 18–30°C and in a pH of 6–9. Catherine et al. [13] and Teubner et al. [14] argued that massive growth is promoted at ratios of 16 TN : 1 TP. Other studies have revealed significant growths at low TN concentrations (0.62–0.74 mg/L) and soluble reactive phosphorus (SRP) levels between 1 and 20 µg/L [9]. However, some studies in lakes have shown that even when waters have recovered to mesotrophic or oligotrophic levels, blooms persist, suggesting that other ecological factors also play an important role [15]. With respect to factors affecting toxin production, Van de Waal et al. [16] found that an increase in TN is related to MC-RR synthesis.

In Mexico, P. agardhii has been previously reported in hypereutrophic lakes. Komárek and Komárková-Legnerová [17] and Pineda-Mendoza et al. [18] analyzed the taxonomic and molecular characteristics of P. agardhii in Xochimilco and Chapultepec urban lakes in Mexico City. Likewise, Vasconcelos et al. [19] reported this species in the Valle de Bravo dam and detected MCs using ELISA. According to Vasconcelos et al. [19], visible blooms of P. agardhii were present in Cuemanco, Mexico City, an artificial water channel used for sports and recreational activities. Molecular and chemical analyses found MCs in Cuemanco to be 4.9 µg MC-LR eq/L. This concentration is comparable to those found in many countries where a potential risk to human health has been confirmed [20–24]. In tropical areas of the Mexican southeast, the presence of cyanobacteria has been frequently reported in the Montebello Lakes National Park, where blue-green waters with different color intensities are commonly observed [25]. The detection of MC-LR in three lakes by ELISA immunoassays was found to be related to the presence of Limnothrix, Planktothrix, and Raphidiopsis spp. as potential producers of the toxin [26]. The lake area of the national park is subject to anthropogenic pressures such as tomato cultivation, which increases the supply of nutrients to the lakes. In addition, the area supplies water to adjacent towns and bears the impact of a growing tourism industry. While these studies represent important contributions to our understanding of cyanobacterial blooms, very few studies in Mexico have characterized the structures of these blooms at a biological and ecological level to determine the causes of their proliferation and their potential effects on the ecosystem. In this sense, the aim of this study is to identify the morphological and molecular characteristics of recurrent populations of Planktothrix and the ecological disturbances that could be related to the presence of cyanotoxins in the Río Grande de Comitán sub-basin and Montebello Lakes National Park, Mexico.

2. Material and Methods

The Río Grande de Comitán sub-basin is located in the National Hydrological Region No. 30 Grijalva-Usumacinta, State of Chiapas [27]. It lies between 16°04′40″–16°10′20″ LN and 91°37′40″–91°47′40″ LW and spans an elevation of 1,380−1,740 masl. The climate is characterized as temperate humid and warm humid, with abundant rains in the summer [28]. The main tributary of the sub-basin is the Río Grande, which runs through urban and agricultural areas until it flows into the Montebello Lakes National Park (Figure 1). The karst origin of the region promotes the circulation of underground water that communicates with a complex system of 59 lagoons [29]. This area is of great ecological, cultural, and economic importance for the region, leading to it becoming established as a protected natural area by presidential decree published in the Diario Oficial de la Federación on December 16, 1959, and later designated as a RAMSAR site in 2003. Since 2003, however, color changes have been observed in the lakes, reportedly related to the increase in phytoplankton biomass as a consequence of the increasing eutrophication of the lakes [26, 30, 31]. The human communities surrounding these lakes utilize the water for both direct use and consumption, as well as for agricultural and silvopastoral activities [28, 32].

2.1. Ecological Characterization

Fieldwork was performed during the rainy season (August 2019), corresponding to the most favorable growth period for cyanobacterial populations in the region [25], in six natural lakes and one sedimentation pond in a water treatment plant from the Río Grande de Comitán sub-basin and Montebello Lakes National Park (Table 1). The sampled lakes were selected based on the presence of blue-green coloration as a possible indicator of cyanobacterial blooms. Temperature, pH, specific conductance, dissolved oxygen, orthophosphate, ammonium, and nitrates were measured for each reservoir with YSI electrodes (Ohio, USA). We sampled one liter per site to monitor water quality and health hazards of recreational waters and the accumulation of algal matter at the downwind end of the lake or shore. The sampled water was kept cold (4°C) for algal isolation and subsequent cultivation in the laboratory. Later, algal samples were preserved in 4% formalin to preserve the useful cytological structures for taxonomic identification. Abundances of each morphospecies were estimated in quadruplicate subsamples in a Neubauer chamber (depth of 0.1 mm and 0.0025 mm² in area) and calculated using the following equation: Abundance (cel/ml) = amount of cells/number of quadrants × 10,000.

To determine water quality in the lakes, one-liter samples of water were collected in sterile polypropylene flasks for bacteriological analyses, stored at 4°C, and processed within 24 h of collection using the membrane filtration technique [33]. Membrane filters (cellulose acetate, 0.45 μm, Millipore MF type HA) were placed in Petri dishes with 2.5 mL of membrane fecal coliform agar medium and incubated at 35°C for 24 h and with Kenner fecal Streptococcus agar for fecal Enterococci and incubated at 44.5°C for 48 h [33].

2.2. Morphological Characterization

For each site sampled, three laminas were observed and their abundance quantified with a Neubauer chamber according to Hötzel and Croome [34]. Specimens collected within sites were measured to determine the morphometric characteristics determined previously to be of taxonomic importance: length and thickness of trichomes, and width and length of vegetative cells [1, 2]. Measurements of morphometric characteristics were made in the most abundant populations collected (Balamtetik, Chaj Chaj, and water treatment plant) in replicates for 60 individuals. Differences in morphometric characters between populations were evaluated by one-way analysis of variance (ANOVA, ) followed by Tukey’s tests to know which means are statistically different from each other. Tests were performed with the STATISTICA v. 3.0 statistical package.

2.3. Molecular Characterization (16S rRNA Gene)

Molecular analyses were carried out on the five samples with the highest cell concentrations (Table 1). DNA extractions were performed using the QIAGEN DNeasy UltraClean Microbial Extraction Kit following the manufacturer’s protocol. The field samples were concentrated with GF/F filters and pretreated to facilitate cell rupture, which consisted of three freeze/thaw cycles with liquid nitrogen and heating on an AccuBlock (Labnet International Inc.) at 65°C. Between each cycle, a drill and plastic pistil were used. The presence of DNA was confirmed by electrophoresis (0.8% agarose gel), and DNA concentration was measured using a microplate spectrophotometer (Epoch: BioTek Instruments Inc., USA).

Amplification of the 16S rRNA gene was performed by PCR using Biometra Tone Thermal Cyclers (Analytik Jena, Göttingen, Germany). The following reaction master mix was used: milli-Q water, 10x PCR buffer, Cl₂Mg (50 mM), deoxyribonucleotide triphosphate (50 μM dNTP), bovine serum albumin (BSA, 0.1%), DNA polymerase (Ultratools DNA Polymerase: 1 unit/μL, and Thermo Scientific DreamTaq DNA Polymerase: 20 and 500 units/μl). The primers (10 pM) used include the oligonucleotides 27F (5′-AGAGTTTGATCCTGGCTCAG-3′) [35] and 23Sr (5′-CTTCGCCTCTGTGTGCCTAGGT-3′) [36]. Subsequently, an agarose gel electrophoresis (1.5%) was performed to reveal the PCR product. Once the DNA bands were obtained, the PCR product was purified using the Wizard SV Gel and PCR Clean-up System Kit (Promega). Subsequently, the cloning procedure using the pGEM-T Easy Vector System Ligation Kit (Promega) was carried out to ensure the greatest obtention of copies of the genetic material and the greatest representativeness of the algal community. The transformation process was carried out using 100 µL of the competent bacteria strain Escherichia coli (DH5a) (Promega). The transformed bacteria were inoculated (250 μL) in Petri dishes with solid LB medium [37], ampicillin (0.1 mg/mL), X-Gal: 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (0.04 mg/mL), and IPTG: isopropyl-β-D-1-thiogalactopyranoside (0.5 mM) [38]. The cultures were incubated at 37°C for 24 hours. Subsequently, the positive clones (presence of the insert) were recognized by their white coloration and reseeded in LB medium. Negative clones (blue colonies without insert) were discarded. The presence of the insert was confirmed by PCR and electrophoresis [38]. The reaction master mix used was the following: milli-Q water, 10x PCR buffer, Cl₂Mg (50 mM), deoxyribonucleotide triphosphate (50 μM dNTP), and DNA polymerase (Ultratools DNA Polymerase: 1 unit/μL and Thermo Scientific DreamTaq DNA Polymerase: 20 and 500 units/μl). As primers (10 pM), the oligonucleotides T7 (5′-TAATACGACTCACTATAGGG-3′) and SP6 (5′-ATTTAGGTGACACTATAG-3′) [39] were used.

Once the presence of the insert was confirmed, the transformed bacteria were cultured in liquid LB medium with ampicillin at 37°C and horizontal movement of 250 rpm for 24 hours. Afterward, the extraction and purification of the plasmids was carried out using the Wizard Plus SV Minipreps DNA Purification System Kit (Promega). Once the plasmid DNA was obtained, its concentration was measured (Epoch: BioTek Instruments Inc., USA), before finally be sent for sequencing [38]. The sequencing process was carried out at the DNA Synthesis and Sequencing Unit (USSDNA) of the Institute of Biotechnology-UNAM (National Autonomous University of Mexico) and the Complutense University of Madrid (Genomic Unit-CAI). The primers used for sequencing were T7 (5′-TAATACGACTCACTATAGGG-3′), SP6 (5′-ATTTAGGTGACACTATAG-3′) [39], and 684F (5′-GTGTAGCGGTGAAATGCGTAGA-3′) [40].

2.3.1. Taxonomic Identification from the Sequences Obtained

The sequences obtained were assembled using the BioEdit 7.2 program [41] to obtain consensus sequences, before a subsequent BLAST analysis (Basic Local Alignment Search Tool: https://blast.ncbi.nlm.nih.gov/Blast.cgi). Sequences with identity percentages above 98% similarity were considered. Together with the results of the morphological identification, a taxonomic identity was obtained for the populations of cyanobacteria analyzed. A phylogenetic tree was built with the sequences obtained for each of the study populations, incorporating similar sequences identified by the BLAST analysis and additional sequences of some genera pertaining to closely related taxonomic groups (https://www.cyanodb.cz/ and https://www.ncbi.nlm.nih.gov/). Once the sequence matrix had been constructed, a multiple alignment was performed using the BioEdit program, followed by a manual revision in the PhyDE-1 V 0.9971 program [42]. Manual alignment was performed under the criterion of maximum parsimony. Next, phylogenies were constructed in the MEGA V.7.0.26 program [43], using the following algorithms: (1) Neighbor Joining, (2) Maximum Parsimony, and (3) Maximum Likelihood. To confirm the genetic variation between species, the RNA-ITS region was analyzed. Sequences from the rRNA-ITS region of P. rubescens (De Candolle ex Gomont) Anagnostidis et Komárek, P. paucivesiculata Gaget, Welker, Rippka et de Marsac, P. agardhii, and P. pseudagardhii Suda et Watanabe were obtained from GenBank and aligned using the ClustalW multiple alignment program in BioEdit. The analysis was performed in the online program CIPRES (phylo.org) using the PAUP tool on XSEDE, under default parameters.

2.4. Isolation and Strains

To confirm the genetic identity and toxicity of Planktothrix populations, samples were isolated from three sites within the study area: Bosque Azul, San Lorenzo, and Paso del Soldado, on July 10, 2023 (Table 1). Unialgal trichomes from the cyanobacterial samples were isolated using a Pasteur pipette under the Olympus SC31 microscope (Japan) and cultured in Petri dishes containing BG11-agar medium. All isolates were subsequently cultivated at 20°C under a 12 : 12 h (light : dark) cycle with a photon flux density of 40–45 μmol photons m² s⁻¹ from white fluorescent lamps. Living cultures were maintained in the laboratory culture collection at the Universidad Autónoma de Madrid, Spain.

2.4.1. Cyanotoxin Gene Detection and Chemical Characterization

To screen for the presence of MC biosynthesis gene clusters, the peptide synthetase-encoding gene mcyE was selected as a target. The following reaction master mix was used: milli-Q water, 10x PCR buffer, Cl₂Mg (50 mM), deoxyribonucleotide triphosphate (50 μM dNTP), and DNA polymerase (QIAGEN DNA Polymerase: 1 unit/μL and Thermo Scientific DreamTaq DNA Polymerase: 20 and 500 units/μl). As primers (10 pM), the oligonucleotides HEPF (5′-TTTGGGGTTAACTTTTTTGGGCATAGTC-3′) and HEPR (5′-AATTCTTGAGGCTGTAAATCGGGTTT-3′) [44] were used.

The PCR products were checked by agarose gel electrophoresis (1.5%), and the purification and cloning of amplified DNA fragments followed previously described procedures. To determine the DNA concentration of the samples, plasmid DNA obtained from the cloning was measured using a NanoDrop UV spectrophotometer. The genes were sequenced on a Sanger 3730xl Sequencer (Thermo Fisher Scientific, MA, USA). Partial sequences were compared to those available in the NCBI database using BLASTn, while the BLAST X tool (blast.ncbi.nlm.nih.gov/Blast.cgi) was used for mcyE gene.

Toxins were extracted from 50 mL culture samples and filtered through Whatman GF/F filters (Whatman International Ltd., Brentford, UK) until saturation and stored at −20°C until extraction. Microcystins were extracted twice with 90% methanol and concentrated by evaporation at 50°C under vacuum.

High-performance liquid chromatography (HPLC) detection of MC-LR and MC-RR microcystin variants was analyzed using HPLC-UV (Shimadzu, mod. Prominence-i, LC-2030C LT) and a diode array detector (SPD-M30A). An Eclipse Plus C18 column (150 × 46 mm, 5 µm) (Agilent) was used as the stationary phase, while mobile phases were characterized by a mixture of 37/63, 30/70% (v/v) of acetonitrile and acetic acid aqueous solution (75 mM) for the MC-LR and MC-RR analyses, respectively. The temperature of the column was fixed at 35°C, and the mobile phase flow rate was fixed at 0.8 mL/min. Both analyses were carried out at 239 nm for both MC-LR and MC-RR. Microcystin concentrations (ppb or ng/ml) were calculated from the area under the curve that was observed at retention times coinciding with the standard substance. This concentration reflects the intracellular amount of MCs in the cyanobacterial cultures analyzed.

3. Results

3.1. Ecological Characteristics

According to physical and chemical measures, the study sites showed the following environmental characteristics: temperate waters (23–25.5°C), mostly neutral to alkaline pH (7.9–9.1), and variable oxygen concentration (3.4–10.6 mg/L). In general, orthophosphate (0.1–38.3 mg/L), ammonium (0.07–6.71 mg/L), and nitrate (0.81–25 mg/L) concentrations were high, and the presence of fecal Enterococci was recurrent in all water bodies, probably related to the urban and agricultural activities around the sampled areas (Table 2).

Based on the PCA (Figure 2), the sites can be classified into three main groups: (1) the first group (the water treatment plant and Efluente) is classified as polluted sites with high fecal Enterococci (0.98), associated with the first component explaining 96.4% of the total variance; (2) the second group is composed of four sites (Balamtetik, Chaj Chaj, San Lorenzo, and Chilpotrero) characterized by high specific conductance (0.97) and associated with the second component explaining 3.5% of the total variance; these sites could represent transitional conditions, as they do not show a positive correlation with nutrient increase; and (3) the third group is represented by three sites (Paso del Soldado, Bosque Azul, and La Encantada) that are characterized by decreased levels of orthophosphate, ammonium, nitrate, and fecal Enterococci.

The abundance of Planktothrix populations showed a similar relationship to the three groups of water bodies recognized by the ecological PCA. The greatest abundance of Planktothrix was present in the treatment plant, followed by Balamtetik, Chaj Chaj, and San Lorenzo, while the lowest abundance was observed in Chilpotrero, Paso del Soldado, and La Encantada (Table 2).

3.2. Morphological Analysis

In the eight bodies of water collected for the present study, mostly solitary trichomes, or formed groups of trichomes, were recorded as free-floating in eutrophic conditions. The trichomes were long (up to 420 µm), straight, without sheaths, immotile, not very constricted at the granulated cross-walls, and 2.69–5.57 µm wide. Cell contents were blue-green colored, with a few big aerotopes. Apical cells were convex with calyptra. These morphological characteristics identify the species as Planktothrix agardhii (Figures 3(a)–3(c)).

The Tukey test revealed significant differences for relative trichome length, cell length, and cell diameter (–0.008) between populations (Table 3).

The ANOVA test found three groups of populations recognized based on cell dimensions (F = 24.92-27.23, ). The first group, from the treatment plant, has cells characterized by having greater cell width (mean = 5.2 µm) but shorter in length (mean = 2.0 µm). The second group, from La Encantada, is characterized by a shorter cellular length (mean = 3.6 µm) but greater cell width (mean = 3.8 µm). The third group, from Efluente, Chaj Chaj, Balamtetik, San Lorenzo, Chilpotrero, and Paso del Soldado, exhibits cellular dimensions that are intermediate between those recorded in the first two groups. There were important overlaps in the trichome lengths between the populations, but the longest trichomes were recorded in San Lorenzo and Chilpotrero (mean = 231.7–245.4 µm), while smaller trichomes were observed in the other populations (mean = 109.13–189.39 µm).

In the water treatment plant, spiral trichomes were recorded in a free-floating bloom (Figure 3(e)). Trichomes were short (<89.8 µm), lacking sheaths, not constricted across walls, rarely motile, with cylindrical cells 3.0–6.0 µm wide, usually shorter than wide, and with mucilaginous sheaths rare. Cell contents were olive-green in color, with several small gas vesicles distributed throughout the cells. The apical cells were rounded to be slightly attenuated, without calyptra. These morphological characteristics key to P. spiroides.

A different morphotype was observed in the Efluente site. Here, the trichomes were short (<83.15 µm), straight, lacking sheaths, slightly constricted across walls, and 3.3–6.4 µm wide. Their cell contents were olive-green in color, with several small aerotopes. Apical cells were convex, without calyptra (Figure 3(d)). These morphological characteristics fail to key to any described species, suggesting that this population may represent a new species, but more taxonomic studies are necessary to confirm this.

3.3. Molecular Analyses

The DNA sequencing of the clones obtained (Figure 4) corroborated the presence of P. agardhii and P. suspensa in Balamtetik (40-1BLTK19), Chaj Chaj (41-1 CHAJ19 and 41-2 CHAJ19), Bosque Azul (B-22 and B2-22), and San Lorenzo (C14–22 and C-22), which all form a clade with a bootstrap support value of 85%. Based on the ITS analysis, these samples are identified as P. agardhii, with values ≤3%. This result is also corroborated by the morphological description (Table 4). The sample from Efluente (44-2 EFT19) was found to be closely affiliated with P. paucivesiculata (BS = 99%) based on the ML tree. However, the ITS analysis shows a clear difference between these two samples, with a value of 6.7%. Based on these results, this population could represent a new species, and further analyses are necessary (e.g., ultrastructural and genetic confirmation in field and strain samples).

3.4. Toxin Results

The PCR analysis revealed the presence of mcyE gene clusters in the strains of P. agardhii from Chaj Chaj (Figure 5). HPLC-UV results reveal the presence of MC-RR and MC-LR in all cultures. The prominent variant in the sample was MC-LR, with 2.0–3.169 μg/L. The MC-RR variant registered values at half to one-third the concentration of MC-LR, with a ratio of 1.96 : 3.02 (Table 5).

4. Discussion

Three clearly distinct morphotypes were observed in the sampled populations. The first, and more abundant, morphotype is characterized by long, straight trichomes, blue-green cell contents containing a few big aerotopes, and convex apical cells with calyptra. According to Komárek and Anagnostidis [2], these characteristics belong to Planktothrix agardhii. The second morphotype is characterized by short, spiral trichomes, cross-walls not constricted, olive-green cell contents with several small aerotopes, and rounded to be slightly attenuated apical cells without calyptra. The form of the trichomes, cross-wall type, and aerotopes are distinctly different from the populations identified as P. agardhii, and according to Liu and collaborators [45], this second morphotype pertains to P. spiroides. The last morphotype is characterized by short, straight trichomes, cross-walls slightly constricted, olive-green cell contents with several small aerotopes, and convex apical cells without calyptra. The short trichomes, aerotope type, and the absence of calyptra differentiate this population from P. agardhii, while the straight trichomes, cross-walls type, and convex apical cells differentiate this population from P. spiroides. This morphotype was not able to be identified from the described species [2, 45–47], suggesting that it may represent a new species.

Morphological variation has been reported as a response to environmental heterogeneity in planktic cyanobacterial populations [3, 48]. While our data showing cellular variation in Planktothrix agardhii populations could reflect morphological responses to the conditions they experience, this variation does not exceed 6 µm in cell width, which is reported as a relevant characteristic by Komárek and Anagnostidis [2] for the species.

The spiral shape of the trichomes recorded in the water treatment plant typically corresponds to descriptions of the Arthrospira–Spirulina group [1], but the degree of coiling is known to vary across environmental parameters or change after extended periods of cultivation [49].

The molecular analyses confirmed the morphological identification of the P. agardhii-like populations, as well as the P. spiroides-like population, as these populations formed monophyletic clades with NCBI sequences of P. agardhii and P. spiroides, respectively, both with high bootstrap values.

While Planktothrix sp. formed a clade with P. paucivesiculata, the morphology was quite different. According to the description of Gaget and collaborators [46], the trichomes in P. paucivesiculata are thinner, slightly curved, and may present sheaths, as well as the apical cells being rounded.

The frequent presence and abundance of P. agardhii throughout the Río Grande de Comitán sub-basin and Montebello Lakes National Park reflects a species with different ecotypes capable of occupying different niches. This was similarly reported in a study on 11 Planktothrix genomes from temperate regions of Europe, which related adaptability to buoyancy capacity, ability to fix atmospheric nitrogen, and unique characteristics of natural products [50].

In recent years, Montebello Lakes National Park has registered an increase in phytoplankton biomass, reflected by evident changes in water color [30, 31, 51]. Likewise, high concentrations of carbon, nitrogen, sulfur, organic matter, and chlorophyll a have also been found in the sediment and seston [52]. The contribution of urban wastewater, the intense agricultural activity, and the use of touristic boats may be related to the water pollution and the dispersal of cyanobacteria in the lake system. The high abundance and broad distribution of Planktothrix populations in the lake system may be present throughout different seasons of the year ([25], this study), indicating a relatively resilient component of the phytoplankton community.

The basin presents a natural connection along the lagoon system, with some bodies of water apparently isolated on the surface but connected underground [53]. The sites sampled in the present study registered the presence of Planktothrix with different abundances, suggesting a natural dispersal by surface transport, by air carriers such as birds, or via various anthropogenic activities such as tourism walks and/or fishing from boats that are shared between the different lakes and not previously sanitized. Consequently, these activities could be favoring the dispersal of species that would not naturally grow in some of the studied lakes.

The highest representation (biomass) of P. agardhii is reportedly associated with autumn, when it tolerates low light intensity and lower temperatures, even in tropical latitude lakes [54–58]. However, this species can prevail in temperate climates or even flourish throughout the year in eutrophic systems [6].

This replacement and/or resilient species characteristic could represent an ecological imbalance, as well as a risk to human health since most of the studied sites are used either for drinking water production or agriculture and recreation purposes. Planktothrix agardhii is known for its ability to synthesize toxins under bloom conditions, and in competitive situations, it can also produce allelopathic compounds to partially offset the costs associated with MC production [59]. This has been observed in both temperate and tropical water bodies, as well as in shallow lakes dominated by P. agardhii and deep stratified lakes harboring P. rubescens [6, 50].

The presence of an MC biosynthetic mcyE gene cluster was confirmed in P. agardhii via sequencing of the mcyE gene and by HPLC-UV analyses. Potentially toxic cyanobacteria possess the MC synthetase mcyE gene cluster that is inactive or absent in nontoxic strains. Currently, more than 200 structural variants of MCs have been isolated and characterized [60], with MC-LR being among the most toxic and widespread worldwide. Effects in humans can even cause death. As such, by 2005, six countries (Brazil, the Czech Republic, Poland, Canada, France, and Spain) had adopted some regulatory measures for MCs in terms of drinking water quality, which are based on the World Health Organization’s provisional TDI (Tolerable Daily Intake) value for MC-LR in drinking water. Three countries (Germany, Finland, and Italy) did not enact their own regulation, but they stated that in cases of potential risk, they would accept the limits proposed by the WHO [7]. In North America, the Environmental Protection Agency (EPA) recommends Health Advisory (HA) levels at or below 0.3 μg/L in drinking water for children preschool age and younger (i.e., less than 6 years old) [61, 62]. For school-age children through adults, the recommended HA levels for drinking water are at or below 1.6 μg/L for MCs.

Confirmation of Planktothrix populations in Mexico via phenetic and genetic analyses has become frequent, showing that these cyanobacteria are becoming abundant (Table 6). The only species recognized for Mexico is P. agardhii, which is currently reported in bodies of water from the center of the country that, due to their high altitude and water temperature less than 20°C, present conditions similar to temperate regions [50]. Molecular methods and enzyme-linked immunosorbent assays (ELISAs) for detecting cyanotoxins show the presence of MCs in sites where Planktothrix populations exist (Table 6). However, those findings are inconclusive since most of the cited analyses were performed on field samples that may contain other potentially toxic cyanobacteria found in the Río Grande de Comitán sub-basin and Montebello Lakes National Park, such as Microcystis spp. [19, 68], Anabaena spp. [70], or Raphidiopsis spp. and Limnothrix spp. ([26], Table 6).

The presence of MCs found in strains collected in this study reveals a risk to human health if the water is to be used for drinking without efficient treatment to remove MCs. Therefore, periodic monitoring in the field is recommended, both in the lake water and in the effluent from the water treatment plant. Another indicator of this risk to human and ecosystem health is the large abundance of these cyanobacteria recorded in the field. Specifically, populations exceeding 25,000 cells/ml were observed in lakes. Values less than 20,000 cells/ml are classified by the WHO [6] as a criterion for notifying the health authorities to start vigilance levels in the water body. Ingestion of MCs may occur through accidental uptake during recreational or occupational activities. In some settings, contaminated food can be a possibly significant source of dietary exposure, including fish and crustaceans collected from lakes, as well as leafy vegetable crops spray-irrigated with water containing cyanobacteria.

The characterization of the morphological and genetic variation, as well as the ecological preferences, of two species of Planktothrix in the sub-basin of the Río Grande de Comitán and Montebello Lakes National Park was conclusive in identifying the species and establishing a baseline assessment of the structure and functioning in the phytoplankton community. The presence and abundance of P. agardhii is notorious throughout the hydrological system, which is disturbed by intense urban, agricultural, and tourist activity. Two variants of MCs in the lakes that directly receive water from the main channel may be related to an increase in runoff nutrients and organic matter that accumulates from the surrounding landscapes. The presence of MCs puts the health of the ecosystem and its inhabitants at risk and represents a situation that should be addressed and resolved with a water management and detoxification strategy specific to the basin. Identifying the biology and health risks of other potentially toxic cyanobacteria reported in the Montebello Lakes National Park (e.g., Anabaenopsis sp., Microcystis sp., Limnothrix sp., and Raphidiopsis sp.) ([25, 26], this study) remains necessary to integrate the cyanobacterial risks into water management strategies for this protected area.

Data Availability

Data are available from the authors upon reasonable request.

Conflicts of Interest

All authors declare that they have no conflicts of interest.

Authors’ Contributions

JCJ and MMH conceptualized the study. JCJ, ACB, ASS, EPU, DOS, and SCG developed the methods. JCJ, IBA, and AISS analyzed the data. JCJ, IBA, and AISS prepared figures and tables for the study. JCJ, ACB, IBA, SCG, and AQC conducted the research, interpreted the data, and wrote the manuscript.

Acknowledgments

Financial support was provided by the Fundación Gonzalo Río Arronte Grant “Strengthening capacities for sustainable water management in communities of the Río Grande de Comitán-Lagos de Montebello basin, Chiapas,” number A-408 (original tittle in Spanish: “Fortalecimiento de capacidades para el manejo sostenible del agua en comunidades de la cuenca del Río Grande de Comitán-Lagos de Montebello, Chiapas número A-408”) and by the CYTED Ibero-American Science and Technology Program for Development (CYTED-2019) through the project TALGENTOX (920PTE0102). Javier Carmona Jiménez thanks the PASPA-DGAPA-UNAM (2022-2023) Support Program for the sabbatical stay at the UAM-Madrid, Spain. DO thanks the Spanish MIU for the FPU predoctoral grant (FPU19/04816) and PAPIIT-DGAPA-UNAM support for this research project (IN206821). The authors would like to thank PhD candidate Brett Butler for English style and grammar correction.

References

K. Anagnostidis and J. Komárek, “Modern approach to the classification system of cyanophytes 3 – oscillatoriales,” Algological Studies, vol. 50–53, pp. 327–472, 1988.
View at: Google Scholar
J. Komárek and K. Anagnostidis, “Süsswasserflora von Mitteleuropa,” Cyanoprokaryota: 2. Teil/2nd Part: Oscillatoriales, vol. 19, Elsevier Spektrum Akademischer Verlag, München, Germany, 2005.
View at: Google Scholar
S. Suda, M. M. Watanabe, S. Otsuka et al., “Taxonomic revision of water-bloom-forming species of oscillatorioid cyanobacteria,” International Journal of Systematic and Evolutionary Microbiology, vol. 52, no. 5, pp. 1577–1595, 2002.
View at: Publisher Site | Google Scholar
Implan, “Municipal Planning Institute of Comitán de Domínguez, In Spanish: Instituto Municipal de Planeación de Comitán de Domínguez,” Management Plan for the Río Grande basin, Lagunas de Montebello, Chiapas, Mexico, 2009.
View at: Google Scholar
M. D. Guiry and G. M. Guiry, AlgaeBase. World-wide Electronic Publication, National University of Ireland, Galway, Ireland, Galway, 2023.
I. Chorus and M. Welker, Toxic Cyanobacteria in Water, CRC Press, Boca Raton (FL), 2nd edition, 2021.
Who, Cyanobacterial Toxins: Microcystins. Background Document for Development of WHO Guidelines for Drinking-Water Quality and Guidelines for Safe Recreational Water Environments, World Health Organization, Geneva, Switzerland, Switzerland, 2020.
Who, “Guidelines for drinking-water quality,” Fourth Edition, Incorporating the 1st Addendum, World Health Organization, Geneva, 2017.
View at: Google Scholar
E. Briand, C. Yéprémian, J. F. Humbert, and C. Quiblier, “Competition between microcystin‐and non‐microcystin producing Planktothrix agardhii (cyanobacteria) strains under different environmental conditions,” Environmental Microbiology, vol. 10, no. 12, pp. 3337–3348, 2008.
View at: Publisher Site | Google Scholar
F. H. Portella Corrêa de Oliveira, A. N. Moura, and Ê.W. Dantas, “Variation in climate determines differences in the effects of abiotic variables on the phytoplankton community in tropical ecosystems,” Marine and Freshwater Research, vol. 69, no. 3, pp. 357–365, 2018.
View at: Publisher Site | Google Scholar
Y. Shimura, T. Fujisawa, Y. Hirose et al., “Complete sequence and structure of the genome of the harmful algal bloom-forming cyanobacterium Planktothrix agardhii NIES-204T and detailed analysis of secondary metabolite gene clusters,” Harmful Algae, vol. 101, 2021.
View at: Publisher Site | Google Scholar
I. Gągała, K. Izydorczyk, A. Skowron et al., “Appearance of toxigenic cyanobacteria in two Polish lakes dominated by Microcystis aeruginosa and Planktothrix agardhii and environmental factors influence,” Ecohydrology and Hydrobiology, vol. 10, no. 1, pp. 25–34, 2010.
View at: Publisher Site | Google Scholar
A. Catherine, C. Quiblier, C. Yéprémian et al., “Collapse of a Planktothrix agardhii perennial bloom and microcystin dynamics in response to reduced phosphate concentrations in a temperate lake,” FEMS Microbiology Ecology, vol. 65, no. 1, pp. 61–73, 2008.
View at: Publisher Site | Google Scholar
K. Teubner, R. Feyerabend, M. Henning, A. Nicklisch, P. Woitke, and J. G. Kohl, “Alternative blooming of Aphanizomenon flos-aquae or Planktothrix agardhii induced by the timing of the critical nitrogen: phosphorus ratio in hypertrophic riverine lakes (With 8 figures and 2 tables),” Ergebnisse der Limnologie, vol. 54, pp. 325–344, 1999.
View at: Google Scholar
K. L. Reinl, J. D. Brookes, C. C. Carey et al., “Cyanobacterial blooms in oligotrophic lakes: shifting the high-nutrient paradigm,” Freshwater Biology, vol. 66, no. 9, pp. 1846–1859, 2021.
View at: Google Scholar
D. B. Van de Waal, G. Ferreruela, L. Tonk et al., “Pulsed nitrogen supply induces dynamic changes in the amino acid composition and microcystin production of the harmful cyanobacterium Planktothrix agardhii,” FEMS Microbiology Ecology, vol. 74, no. 2, pp. 430–438, 2010.
View at: Publisher Site | Google Scholar
J. Komárek and J. Komárková-Legnerová, “Contribution to the knowledge of planktic cyanoprokaryotes from central Mexico,” Preslia, no. 74, pp. 207–233, 2002.
View at: Google Scholar
R. Pineda-Mendoza, F. Martínez-Jerónimo, G. Garduño-Solórzano, and R. Olvera-Ramírez, “Morphological and molecular characterization of filamentous cyanobacteria isolated from blooms from three eutrophic urban lakes in Mexico City (Caracterización morfológica y molecular de cianobacterias filamentosas aisladas de florecimientos de tres lagos urbanos eutróficos de la ciudad de México),” Polibotánica, vol. 31, pp. 31–50, 2011.
View at: Google Scholar
V. Vasconcelos, A. Martins, M. Vale et al., “First report on the occurrence of microcystins in planktonic cyanobacteria from Central Mexico,” Toxicon, vol. 56, no. 3, pp. 425–431, 2010.
View at: Publisher Site | Google Scholar
K. Sivonen and G. Jones, “Cyanobacterial toxins,” in Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring, and Management, I. Chorus and J. Bartram, Eds., pp. 41–111, E & FN Spon, London, UK, 1999.
View at: Google Scholar
Q. Catherine, W. Susanna, E. S. Isidora, H. Mark, V. Aurélie, and H. Jean-François, “A review of current knowledge on toxic benthic freshwater cyanobacteria--ecology, toxin production and risk management,” Water Research, vol. 47, no. 15, pp. 5464–5479, 2013.
View at: Publisher Site | Google Scholar
J. E. Niamien-Ebrottie, S. Bhattacharyya, P. R. Deep, and B. Nayak, “Cyanobacteria and cyanotoxins in the world: review,” International Journal of Applied Research 1, pp. 563–569, 2015.
View at: Google Scholar
S. A. Wood, L. Kelly, K. Bouma-Gregson et al., “Toxic benthic freshwater cyanobacterial proliferations: challenges and solutions for enhancing knowledge and improving monitoring and mitigation,” Freshwater Biology, vol. 65, no. 10, pp. 1824–1842, 2020.
View at: Publisher Site | Google Scholar
M. Muñoz, S. Cirés, Z. M. de Pedro et al., “Overview of toxic cyanobacteria and cyanotoxins in Ibero-American freshwaters: challenges for risk management and opportunities for removal by advanced technologies,” Science of the Total Environment, vol. 761, 2021.
View at: Publisher Site | Google Scholar
T. Almeida, “Spatial heterogeneity in the Montebello lake system: functional and taxonomic structure of phytoplankton (Heterogeneidad espacial en el sistema lacustre de Montebello: estructura funcional y taxonómica del fitoplancton),” Bachelor Thesis. FES-Iztacala, National Autonomous University of Mexico, Mexico, MX, USA, 2014.
View at: Google Scholar
R. Fernández, J. Alcocer, and L. A. Oseguera, “Microcystins presence threatens the ecosystem health of a tropical National Park: Lagunas de Montebello, Chiapas,” Brazilian Journal of Botany, vol. 44, no. 1, pp. 207–212, 2021.
View at: Publisher Site | Google Scholar
Conanp (National Commission of Protected Natural Areas, In Spanish: Comisión Nacional de Áreas Naturales Protegidas), “Lagunas de Montebello National Park “water quality monitoring program” Study to monitor the water quality parameters of the lagoons connected to the Tepancoapan lagoon system,” Comitán de Domínguez, Chiapas. Mexico, 2011.
View at: Google Scholar
E. García, Modifications to the Köppen Climate Classification System, Institute of Geography, Mexico, MX, USA, 2004.
M. A. Vázquez and E. Méndez, General Aspects of the Region: Montebello Lakes, Work Report for the Nature Conservation and Natural Resources Course, Master of Science: Natural Resources and Rural Development. ECOSUR. Chiapas, Mexico, MX, USA, 1994.
J. Alcocer, B. Prado, L. Mora, L. A. Oseguera, and M. Caballero, “Sediment characteristics of tropical, karst lakes and their relationship with watershed topography, lake morphometry, and human activities,” Journal of Paleolimnology, vol. 66, no. 3, pp. 333–353, 2021.
View at: Publisher Site | Google Scholar
A. Yanez-Montalvo, B. Aguila, E. S. Gómez-Acata et al., “Shifts in water column microbial composition associated to lakes with different trophic conditions: “Lagunas de Montebello” National Park, Chiapas, Mexico,” PeerJ, vol. 10, 2022.
View at: Publisher Site | Google Scholar
Conanp (National Commission of Protected Natural Areas, In Spanish: Comisión Nacional de Áreas Naturales Protegidas), “Conservation and Management Program Lagunas de Montebello National Park,” 2007, https://www.conanp.gob.mx/que_hacemos/pdf/programas_manejo/Final_Montebello.pdf.
View at: Google Scholar
Apha (American Public Health Association), “American water works association and water environmental federation,” Standard Methods for Examination of Water and Wastewater, Port City Press, Lochearn, Maryland, 2005.
View at: Google Scholar
G. Hötzel and R. Croome, A Phytoplankton Methods Manual for Australian Freshwaters, Land and Water Resources Research and Development Corporation, Australia, 1999.
A. Wilmotte, J. M. Neefs, and R. De Wachter, “Evolutionary affiliation of the marine nitrogen-fixing cyanobacterium Trichodesmium sp. strain NIBB 1067, derived by 16S ribosomal RNA sequence analysis,” Microbiology, vol. 140, no. 8, pp. 2159–2164, 1994.
View at: Publisher Site | Google Scholar
C. Lepère, A. Wilmotte, and B. Meyer, “Molecular diversity of Microcystis strains (Cyanophyceae, Chroococcales) based on 16S rDNA sequences,” Systematics and Geography of Plants, vol. 70, no. 2, pp. 275–283, 2000.
View at: Publisher Site | Google Scholar
G. Bertani, “Studies on lysogenesis I: the mode of phage liberation by lysogenic Escherichia coli,” Journal of Bacteriology, vol. 62, no. 3, pp. 293–300, 1951.
View at: Publisher Site | Google Scholar
J. Carmona Jiménez, A. Caro Borrero, I. Becerra‐Absalón, E. Perona Urizar, K. Márquez Santamaría, and P. Mateo Ortega, “Description of two new species of Nostoc (Nostocales, Cyanobacteria) from central Mexico, using morphological, ecological, and molecular attributes,” Journal of Phycology, vol. 59, no. 6, pp. 1237–1257, 2023.
View at: Publisher Site | Google Scholar
D. A. Melton, P. A. Krieg, M. R. Rebagliati, T. Maniatis, K. Zinn, and M. R. Green, “Efficient in vitro syn- thesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter,” Nucleic Acids Research, vol. 12, no. 18, pp. 7035–7056, 1984.
View at: Publisher Site | Google Scholar
P. Mateo, E. Perona, E. Berrendero, F. Leganés, M. Martín, and S. Golubić, “Life cycle as a stable trait in the evaluation of diversity of Nostoc from biofilms in rivers,” FEMS Microbiology Ecology, vol. 76, no. 2, pp. 185–198, 2011.
View at: Publisher Site | Google Scholar
T. Hall, “BioEdit version 7.0. 0,” 2004, http://www.mbio.ncsu.edu/BioEdit/bioedit.html.
View at: Google Scholar
J. Müller, K. Müller, C. Neinhuis, and D. Quandt, “PhyDE®- phylogenetic data,” 2010, http://www.phyde.de.
View at: Google Scholar
S. Kumar, G. Stecher, and K. Tamura, “MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets,” Molecular Biology and Evolution, vol. 33, no. 7, pp. 1870–1874, 2016.
View at: Publisher Site | Google Scholar
A. D. Jungblut and B. A. Neilan, “Molecular identification and evolution of the cyclic peptide hepatotoxins, microcystin and nodularin, synthetase genes in three orders of cyanobacteria,” Archives of Microbiology, vol. 185, no. 2, pp. 107–114, 2006.
View at: Publisher Site | Google Scholar
Y. Liu, Z. Wang, S. Lin, G. Yu, and R. Li, “Polyphasic characterization of Planktothrix spiroides sp. nov. (Oscillatoriales, Cyanobacteria), a freshwater bloom-forming alga superficially resembling Arthrospira,” Phycologia, vol. 52, no. 4, pp. 326–332, 2013.
View at: Publisher Site | Google Scholar
V. Gaget, M. Welker, R. Rippka, and N. T. de Marsac, “A polyphasic approach leading to the revision of the genus Planktothrix (Cyanobacteria) and its Type species, P. agardhii, and proposal for integrating the emended valid botanical taxa, as well as three new species, Plaktothrix paucivesiculata sp. nov., Planktothrix tepida sp.nov., and Planktothrix serta sp. nov., as genus and species names with nomenclatural standing under the ICNP,” Systematic & Applied Microbiology, vol. 38, no. 3, pp. 141–158, 2015.
View at: Publisher Site | Google Scholar
F. Heidari, J. Zima, H. Riahi, and T. Hauer, “New simple trichal cyanobacterial taxa isolated from radioactive thermal springs,” Fottea, vol. 18, no. 2, pp. 137–149, 2018.
View at: Publisher Site | Google Scholar
L. Yema, E. Litchman, and P. de Tezanos Pinto, “The role of heterocytes in the physiology and ecology of bloom-forming harmful cyanobacteria,” Harmful Algae, vol. 60, pp. 131–138, 2016.
View at: Publisher Site | Google Scholar
K. Gao, P. Li, T. Watanabe, and E. Walter Helbling, “Combined effects of ultraviolet radiation and temperature on morphology, photosynthesis, and dna of Arthrospira (Spirulina) platensis (Cyanophyta) 1,” Journal of Phycology, vol. 44, no. 3, pp. 777–786, 2008.
View at: Publisher Site | Google Scholar
C. Pancrace, M. A. Barny, R. Ueoka et al., “Insights into the Planktothrix genus: genomic and metabolic comparison of benthic and planktic strains,” Scientific Reports, vol. 7, no. 1, 2017.
View at: Publisher Site | Google Scholar
D. Ávila- García, J. Morató, A. Pérez-Maussán, P. Santillán-Carvantes, J. Alvarado, and F. A. Comín, “Impacts of alternative land-use policies on water ecosystem services in the Río Grande de Comitán-Lagos de Montebello watershed, Mexico,” Ecosystem Services, vol. 45, 2020.
View at: Publisher Site | Google Scholar
M. H. Ranjbar, D. Hamilton, A. Etemad-Shahidi, and F. Helfer, “Individual-based modelling of cyanobacteria blooms: physical and physiological processes,” Science of The Total Environment, vol. 792, 2021.
View at: Publisher Site | Google Scholar
J. Alcocer, L. A. Oseguera, G. Sánchez, C. González, R. Martínez, and R. González, “Bathymetric and morphometric surveys of the Montebello lakes, Chiapas,” Journal of Limnology, vol. 75, no. s1, pp. 56–65, 2016.
View at: Publisher Site | Google Scholar
B. W. Ibelings, R. Portielje, E. H. Lammens et al., “Resilience of alternative stable states during the recovery of shallow lakes from eutrophication: lake Veluwe as a case study,” Ecosystems, vol. 10, no. 1, pp. 4–16, 2007.
View at: Publisher Site | Google Scholar
M. Kokociński, K. Stefaniak, J. Mankiewicz-Boczek, K. Izydorczyk, and J. Soininen, “The ecology of the invasive cyanobacterium Cylindrospermopsis raciborskii (Nostocales, Cyanophyta) in two hypereutrophic lakes dominated by Planktothrix agardhii (Oscillatoriales, Cyanophyta),” European Journal of Phycology, vol. 45, no. 4, pp. 365–374, 2010.
View at: Publisher Site | Google Scholar
S. Bonilla, L. Aubriot, M. C. S. Soares et al., “What drives the distribution of the bloom-forming cyanobacteria Planktothrix agardhii and Cylindrospermopsis raciborskii?” FEMS Microbiology Ecology, vol. 79, no. 3, pp. 594–607, 2012.
View at: Publisher Site | Google Scholar
D. Salvador, C. Churro, and E. Valério, “Evaluating the influence of light intensity in mcyA gene expression and microcystin production in toxic strains of Planktothrix agardhii and Microcystis aeruginosa,” Journal of Microbiological Methods, vol. 123, pp. 4–12, 2016.
View at: Publisher Site | Google Scholar
M. U. G. Barros, I. K. C. Lopes, S. M. D. C. Carvalho, and J. Capelo Neto, “Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs,” RBRH, vol. 22, no. 0, 2017.
View at: Publisher Site | Google Scholar
E. Briand, M. Gugger, J. C. François, C. Bernard, J. F. Humbert, and C. Quiblier, “Temporal variations in the dynamics of potentially microcystin-producing strains in a bloom-forming Planktothrix agardhii (cyanobacterium) population,” Applied and Environmental Microbiology, vol. 74, no. 12, pp. 3839–3848, 2008.
View at: Publisher Site | Google Scholar
B. Nowruzi, I. Becerra-Absalón, and J. S. Metcalf, “A novel microcystin-producing cyanobacterial species from the genus desmonostoc, Desmonostoc alborizicum sp. nov., isolated from a water supply system of Iran,” Current Microbiology, vol. 80, no. 1, p. 49, 2022.
View at: Google Scholar
Epa, “Drinking Water Health Advisory for the Cyanobacterial Toxin Microcystin,” 2015, https://www.epa.gov/sites/default/files/2017-06/documents/microcystins-report-2015.pdf.
View at: Google Scholar
Epa, “Drinking water health advisory for the cyanobacterial toxin cylindrospermopsin,” 2015, https://www.epa.gov/sites/default/files/2017-06/documents/cylindrospermopsin-report-2015.pdf.
View at: Google Scholar
R. M. R. Pineda-Mendoza, Olvera-Ramírez, and F. Martínez-Jerónimo, “Microcystins produced by filamentous cyanobacteria in urban lakes. A case study in Mexico City,” Hidrobiologica, vol. 22, no. 3, pp. 290–298, 2012.
View at: Google Scholar
R. Pineda-Mendoza, C. Briones-Roblero, R. González-Escobedo, F. Rivera-Orduña, F. Martínez-Jerónimo, and G. Zúniga, “Seasonal changes in the bacterial community structure of three eutrophicated urban lakes in Mexico City, with emphasis on Microcystis spp,” Toxicon, vol. 179, pp. 8–20, 2020.
View at: Publisher Site | Google Scholar
M. A. Gayosso-Morales, S. Nandini, F. Martínez-Jeronimo, and S. Sarma, “Effect of organic and inorganic turbidity on the zooplankton community structure of a shallow waterbody in Central Mexico (Lake Xochimilco, Mexico),” Journal of Environmental Biology, vol. 38, no. 6(SI), pp. 1183–1196, 2017.
View at: Google Scholar
L. Favari, E. López, L. Martı́nez-Tabche, and E. Dı́az-Pardo, “Effect of insecticides on plankton and fish of ignacio ramirez reservoir (Mexico): a biochemical and biomagnification study,” Ecotoxicology and Environmental Safety, vol. 51, no. 3, pp. 177–186, 2002.
View at: Publisher Site | Google Scholar
C. A. Z. Barrios, S. Nandini, and S. S. S. Sarma, “Effect of crude extracts from cyanobacterial blooms in Lake Texcoco (Mexico) on the population growth of Brachionus calyciflorus (Rotifera),” Toxicon, vol. 139, pp. 45–53, 2017.
View at: Publisher Site | Google Scholar
C. Zamora-Barrios, S. Nandini, and S. S. S. Sarma, “Bioaccumulation of microcystins in seston, zooplankton and fish: a case study in Lake Zumpango, Mexico,” Environmental Pollution, vol. 249, pp. 267–276, 2019.
View at: Publisher Site | Google Scholar
M. Gaytán-Herrera, V. Martínez-Almeida, G. Oliva-Martínez, A. Durán-Díaz, and P. Ramirez-Garcia, “Temporal variation of phytoplankton from the tropical reservoir Valle de Bravo, Mexico,” Journal of Environmental Biology, vol. 32, no. 1, pp. 117–126, 2011.
View at: Google Scholar
J. L. Alillo-Sánchez, M. L. Gaytán-Herrera, V. M. Martínez-Almeida, and P. Ramírez-García, “Microcystin-LR equivalents and their correlation with Anabaena spp. in the main reservoir of a hydraulic system of Central Mexico,” Inland Waters, vol. 4, no. 3, pp. 327–336, 2014.
View at: Publisher Site | Google Scholar
S. J. E. Rea, “Standardization of a molecular PCR technique to identify the presence of the mcyE gene in monocultures and its monitoring in environmental samples of potentially toxic cyanobacteria (Estandarización de una técnica milecular de PCR para identificar la presencia del gen mcyE en monocultivos y su seguimiento en muestras ambientales de cianobacterias potencialmente tóxicas),” Bachelor's thesis. Facultad de Estudios Superiores Iztacala, National Autonomous University of Mexico, Mexico, MX, USA, 2015.
View at: Google Scholar
M. E. Pérez-López, “Relationship of phosphorus and nitrogen content with the presence of toxic cyanophyceae in the El Tunal River,” in Durango, Mexico (Relación del contenido de fósforo y nitrógeno con la presencia de cianoficeas tóxicas en el río El Tunal, en Durango, México). Short term project CSIP 20120668, CIIDIR-Durango IPN, Mexico, MX, USA, 2012.
View at: Google Scholar

Copyright

Copyright © 2024 Javier Carmona Jiménez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

PDF Download Citation

Download other formats

Order printed copies

Views

82

Downloads

53

Citations