an abrupt global warming event has been recorded in many parts of the world in sediments of latest maastrichtian age between 65.45-65.10 ma. this warm event was documented here at a section near ziyarat-kola in central alborz based on analysis of planktonic foraminifera. an unusual abundance of normally large-size species such as globotruncana arca, globigerinelloides subcarinatus, pseudoguembe...

The techniques of flow cytometry, scanning and transmission electron microscopy, and confocal scanning laser microscopy were used to study the physiology of Staphylococcus aureus in the early stages of surface-attached culture, and to make direct comparisons with planktonic bacteria grown under the same conditions. Attached bacteria growing in nutrient-rich batch culture were found to go throug...

AbstractThe Aitamir Formation is divided into two members the lower sandstone and the upper shale. 32 genera and 57 species of foraminifera have been recognized. According to identified foraminifera Rotalipora appenninica Interval Zone, Rotalipora globotruncanoides (Rotalipora brotzeni) interval zone and Whiteinella aumalensis-Dicarinella canaliculata assemblage zone are proposed and a l Albian...

Diatoms are abundant in biofilms developed on surfaces immersed in sunlit waters. In both the planktonic and the biofilm mode of growth, diatoms produce carbohydrate polymers which perform several functions including motility, protection, production of macro-aggregates and detoxification. However, little is known about the differences, if any, in the production and characterization at the molec...

This study investigated the physiology and behaviour following treatment with ortho-phthalaldehyde (OPA), of Pseudomonas fluorescens in both the planktonic and sessile states. Steady-state biofilms and planktonic cells were collected from a bioreactor and their extracellular polymeric substances (EPS) were extracted using a method that did not destroy the cells. Cell structure and physiology af...

BACKGROUND To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. OBJECTIVES The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. MATERIALS AND METHODS Forty clinical isolates of Escherichi...

Mutualistic interactions in planktonic microbial communities have been extensively studied. However, our understanding on mutualistic communities consisting of co-existing planktonic cells and biofilms is limited. Here, we report a planktonic cells-biofilm mutualistic system established by the fermentative bacterium Escherichia coli and the dissimilatory metal-reducing bacterium Shewanella onei...

The human pathogen Pseudomonas aeruginosa is capable of causing both acute and chronic infections. Differences in virulence are attributable to the mode of growth: bacteria growing planktonically cause acute infections, while bacteria growing in matrix-enclosed aggregates known as biofilms are associated with chronic, persistent infections. While the contribution of the planktonic and biofilm m...