The bactericidal effect of green macroalgae Cladophora sp. from freshwater toward Gram-negative and Gram-positive bacteria

Aims@#The development of new antimicrobial agents towards multidrug-resistant bacteria is one of the most significant challenges facing the healthcare system today. The continuous increase of antimicrobial resistance rates worldwide is a significant threat to public health. Therefore, this study aimed to investigate the antibacterial effect of filamentous macroalgae Cladophora sp. The sample was collected from an Algerian fountainhead of fresh water. A crude hydromethanolic extract (methanol-water) was tested against two standard Gram-negative bacteria: Escherichia coli ATCC25922 and Pseudomonas aeruginosa ATCC27853, and two standard Gram-positive bacteria: Staphylococcus aureus ATCC25923 and Enterococcus faecalis ATCC 2921. @*Methodology and results@#The antibacterial effect of the hydromethanolic extract of Cladophora sp. was investigated using the well diffusion method to determine the inhibitory diameters and the dilution methods to determine the minimum inhibitory concentration (MIC) and the bactericidal inhibitory concentration (MBC). The results indicated that the hydromethanolic extract of Cladophora sp. is more effective towards Gram-positive bacteria, with a significant effect on S. aureus ATCC 25923, where an inhibitory diameter of 35 mm was recorded. For the Gram-negative, E. coli ATCC25922 was more susceptible with inhibitory diameters of 46 mm, followed by P. aeruginosa ATCC 27853 with 28 mm. The MIC value of hydromethanolic extract of Cladophora sp. was 50 µg/mL for Gram-positive bacteria (S. aureus ATCC25923 and E. faecalis ATCC29212). However, it was 100 µg/mL for Gram-negative bacteria (E. coli ATCC25922 and P. aeruginosa ATCC 27853). The best bactericidal effect was observed with Gram-positive with an MBC of 100 µg/mL. The MBC for Gram-negative bacteria was 150 µg/mL. @*Conclusion, significance and impact of study@#The Cladophora sp. macroalgae represent a potential source of bioactive compounds, which could be used in the management and treatment of various microbial infections.

Preliminary phytochemical screening and GC-MS analysis of Cladophora glomerata: green marine algae

Background: Seaweeds since ages are excellent source of biologically active ingredients. Several Asian countries have a strong tradition of using various seaweeds in herbal medicines preparations. These plants contain various phytochemical constituents having biological activities. Seaweeds are the source of phytochemicals namely agar-agar, carrageenan and algin, which are extensively used in various industries such as food, confectionary, textiles, pharmaceuticals, dairy and paper industries mostly as gelling, stabilizing and thickening agents. They are also used for human consumption, animal feed and as manure in several countries. Several Asian countries are using various seaweeds in traditional medicines.Methods: In the present study, the shade dried and methanolic extract of Cladophora glomerata, a marine green algae was subjected to preliminary phytochemical and gas chromatography-mass spectrometry analysis(GC-MS) to identify the various bioactive components.Results: The methanolic extract of Cladophora glomerata revealed the presence of alkaloids, glycosides, flavonoids, saponins, diterpenes and carbohydrates. The GC-MS analysis of the methanolic extract of Cladophora glomerata showed the presence of 42 different compounds. The major compounds were dibutyl phthalate (27.07%), hexadecanoic acid, methyl ester (9.58%), 1,2-benzene-di-carboxylic acid (8.11%), octatriacontyl trifluoroacetate (6.81%), cholesterol (6.66%).Conclusions: Thus, in the present study of Cladophora glomerata, phytochemical and GC-MS analysis provides an important novel information to support further ongoing studies to evaluate structure of bioactive compound and its pharmacological activities.

Photoacclimation in a tropical population of Cladophora glomerata (L.) Kützing 1843 (Chlorophyta) from southeastern Brazil

Photoacclimation of photosynthesis was investigated in a tropical population of C. glomerata (São Paulo State, southeastern Brazil, 20º 48’ 24" S and 49º 22’ 24" W) by chlorophyll fluorescence parameters and chlorophyll a content. Plants were acclimated to two levels of irradiance: low (65 ± 5 µmol.m-2.s-1) and high (300 ± 10 µmol.m-2.s-1) and exposed short-term (4 days) and long-term (28 days) under a light-dark cycle of 12:12 hours. Photosynthesis-irradiance (PI) curves revealed distinct strategies of photoacclimation. In long-term exposure, plants acclimated by altering the photosynthetic units (PSU) number and keeping fixed the PSU size, revealed by increased rates of maximum photosynthesis (Pmax), lower photosynthetic efficiency (alpha) and higher values of the saturation parameter (Ik) under high irradiance. The short-term acclimation strategy consisted of changing the PSU size, with a fixed number of PSUs, as revealed by similar Pmax but higher alpha and lower Ik under low irradiance. Chlorophyll a contents followed the general pattern reported in green algae of higher concentrations under lower irradiance. Dark/light induction curves revealed consistently higher values of potential quantum yield under low irradiance. Initial and final values showed a higher recovery capacity in the short (84.4-90.6 percent) term exposure than in the long-term case (81.4-81.5 percent). ETR (electron transport rate) and NPQ (non-photochemical quenching) values were consistently higher under low irradiance. ETR showed a continuous and steady increase along the light exposure period in the short and long-term experiments, whereas NPQ values revealed a rapid increase after 15 seconds of light exposure, kept a slightly increasing trend and stabilized in most treatments. Lower photosynthetic performance (ETR) and recovery capacity of potential quantum yield were observed, particularly in long-term exposure, suggesting that this population...

A fotoaclimatação da fotossíntese foi investigada numa população tropical de Cladophora glomerata (Estado de São Paulo, sudeste do Brasil, 20º 48’ 24" S e 49º 22’ 24" W) através de parâmetros de fluorescência da clorofila e conteúdo de clorofila a. As plantas foram aclimatadas a dois níveis de irradiância: baixa (65 ± 5 µmol.m-2.s-1) e alta (300 ± 10 :mol.m-2.s-1) e expostas a curto período (4 dias) e longo período (28 dias) em fotoperíodo de 12 horas. Curvas de fotossíntese-irradiância (FI) revelaram estratégias distintas de fotoaclimatação. Plantas expostas a longo período aclimataram pela alteração do número de unidades fotossintéticas (UF) e mantiveram fixo o tamanho das UF. Estas características foram reveladas por menores taxas de fotossíntese máxima (Fmax), menor eficiência fotossintética (alfa) e valores mais altos do parâmetro de saturação (Ik) em alta irradiância. A estratégia de aclimatação em curto período consistiu em mudança no tamanho das UF, com número fixo de UF, conforme revelado por taxas semelhantes de fotossíntese máxima (Fmax), maiores valores de alfa e menores de Ik em baixa irradiância. Os conteúdos de clorofila a seguiram o padrão geral reportado para algas verdes de maiores concentrações em baixa irradiância. Curvas de indução escuro/luz revelaram valores consistentemente mais elevados de rendimento quântico potencial em baixa irradiância. Valores iniciais e finais mostraram capacidade de recuperação mais elevada em curto período (84,4-90,6 por cento) do que em longo período (81,4-81,5 por cento). Os valores da taxa de transporte de elétrons (ETR) e extinção não-fotoquímica (NPQ) foram consistentemente mais elevados em baixa irradiância. Os valores de ETR tiveram aumento contínuo e estável ao longo do período de exposição luminosa em curto e longo períodos, enquanto que os de NPQ revelaram aumento rápido após 15 seconds de exposição à luz, mantiveram leve tendência de aumento e então estabilizaram...