Quantification of microcystin-producing microcystis in freshwater bodies in the Southern Mozambique using quantitative real time polymerase chain reaction

Abstract

In the last decades, large number of reported cases of illnesses in Mozambique is related to drinking water. However, only a limited number of studies have focused on aquatic pollution in this country. Cyanobacterial blooms dominated by Microcystis sp are regularly identified in freshwater bodies in Mozambique. Microcystis is known to proliferate in freshwater bodies and produce microcystins which have adverse effects on animals and humans. The aim of this study was to quantify microcystinproducing Microcystis in three different freshwater bodies in Southern Mozambique. TaqMan based real time polymerase chain reaction (PCR) (Taq Nuclease Assay) was used to quantify populations of Microcystis in three aquatic ecosystems in Southern Mozambique. Total Microcystis spp (microcystinproducing and non-producing strains) were quantified in the three selected study areas with the determination of the copy numbers of the phycocyanin (PC) operon. Microcystin-producing gene copy numbers were quantified using specific primer pair, amplifying the mcyB gene. Microcystis mcyB copy numbers varied from 4.2 x 10 6 to 1.6 x 10 9 gene copies /L in 2008, corresponding to 2.15 to 98.55% of total Microcystis, and from 9.6 x 10 7 to 4.5

Microcystin Incidence in the Drinking Water of Mozambique: Challenges for Public Health Protection

“…These data indicate that many people of Mozambique consume food and water unsafely. Few studies (Figure 1) were done by Pedro et al [117][118][119] and Bojcevska and Jergil [120] in Pequenos Libombos dam, Nhambavale lake, Chòkwé irrigation channels and Chidenguele sites in the South of Mozambique during 2003Mozambique during , 2008Mozambique during , and 2009 and their studies indicated the occurrence of MC-LR, -YR, and -RR produced by Microcystis sp. (M. novacekii, botrys and other) and Cylindrospermopsis raciborskii [117][118][119][120] (Table 4).…”

“…Few studies (Figure 1) were done by Pedro et al [117][118][119] and Bojcevska and Jergil [120] in Pequenos Libombos dam, Nhambavale lake, Chòkwé irrigation channels and Chidenguele sites in the South of Mozambique during 2003Mozambique during , 2008Mozambique during , and 2009 and their studies indicated the occurrence of MC-LR, -YR, and -RR produced by Microcystis sp. (M. novacekii, botrys and other) and Cylindrospermopsis raciborskii [117][118][119][120] (Table 4). MC concentration varies from less than 0.01 (below quantification levels) to 0.02 in Pequenos Libombos dam, less to 0.01 to 0.68 in Chòkwé irrigation channels, 0.86 to 7.82 in Nhambavale lake and 0.57 to 6.83 µg•L −1 in Chidenguele.…”

“…However, this might be underestimated due to a lack of monitoring facilities and/or a lack of public health staff trained for recognizing symptoms of MCs intoxication since the presence of high MCs concentration was reported in Maputo and Gaza provinces. Few studies done in Maputo and Gaza provinces indicated the occurrence of MC-LR, -YR, and -RR at a concentration ranging from 6.83 to 7.78 µg•L −1 [117][118][119][120], which are very high, around 7 times above the maximum limit (1 µg•L −1 ) recommended by WHO [59]. The potential MC-producing in the studied sites is mostly Microcystis sp.…”

“…The potential MC-producing in the studied sites is mostly Microcystis sp. [117][118][119][120]. However, MC distribution in Mozambique is unknown, and a monitoring program would help to understand the dimension of the problem.…”