The effect of bacteria on diatom community structure – the ‘antibiotics’ approach

Abstract

To investigate the effect of bacteria on diatoms at the community level, sediment samples from an intertidal tropical environment were treated with penicillin (a β-lactam antibiotic that can affect diatoms only through bacteria). Streptomycin (an aminoglycoside) and chloramphenicol, antibiotics that can potentially affect protein synthesis in diatom organelles and photosynthesis, were also used for comparison. The changes in diatom community structure and the resistant and tolerant bacterial fractions were analyzed through microscopy, culture techniques and denaturing gradient gel electrophoresis. The reduction in bacterial abundance when treated with penicillin resulted in suppression of Amphora coffeaeformis, a dominant diatom in the study area. The bacterial community preferred the 'tolerance' strategy over 'resistance' in response to treatment with penicillin; these changes in bacterial dynamics were probably linked to concurrent changes in diatom community structure. The observations with penicillin differed from those with streptomycin that did not seem to significantly affect diatoms, and chloramphenicol, which consistently inhibited diatoms. Overall, the results of this study highlight the significance of bacteria in structuring benthic diatom communities and call for the inclusion of the 'antibiotics' approach in studies addressing diatom-bacterial interactions at the community level.

Interactions of bacteria with diatoms: influence on natural marine biofilms

“…Overall, in the present work, streptomycin and chloramphenicol did not inhibit bacteria. These observations differ from those in similar experiments by D'Costa & Anil () on benthic diatom communities. In the latter study, streptomycin and chloramphenicol inhibited bacteria to <10 and 77% of control values, respectively.…”

Anti-Biofilm Effect of Biodegradable Coatings Based on Hemibastadin Derivative in Marine Environment

“…5M6) and one diatom strain ( C. closterium ). Bacteria and diatoms are very close in fouling biofilms [ 44 ], and they might support each other by exchange of chemical cues [ 45 ]. The mixed biofilm, constituted of bacteria and diatoms in symbiotic relation, can establish a resistant consortium against AF agents.…”

The possible role of bacterial signal molecules N-acyl homoserine lactones in the formation of diatom-biofilm ( Cylindrotheca sp.)

“…It was reported that the interaction between diatoms and bacteria in biofilm might be regulated by a complex network of chemical factors including EPS and other substances (Khandeparker et al, 2014). For example, bacteria influenced the diatom community structure by antibiotic-mediated interactions (D'Costa and Anil, 2011). Recently, Windler et al (2015) reported that the bacteria Bacteroidetes strain 32 influenced the biofilm structure and biomass of the diatom Achnanthidium minutissimum and pointed out that little was know about the chemical interactions between diatoms and bacteria.…”

“…The relationships between diatoms and bacteria are very close in fouling biofilms. In addition to being symbiotic or antagonistic, diatoms and bacteria might support each other through cross-feeding, possibly optimize by exchange of chemical cues (D'Costa and Anil, 2011). It was reported that bacteria influenced the growth and metabolic activities of diatoms, such as EPS production, capsule formation and adhesion strength of diatom cells (WigglesworthCooksey and Cooksey, 2005).…”