dissabte, 2 de maig de 2015

DESTINO DE UMA CÉLULA GENETICAMENTE DETERMINADA DURANTE CICLO CELULAR PLANO DE DIVISÃO PODE DETERMINAR DESTINO DE CÉLULAS FILHAS ...ALGAL PRODUCTS ...DIATOMACEOUS EARTH AND HYDROCOLLOIDS CARRAGENAN Sequences and secondary structures of the nuclear-encoded internal transcribed spacer 2 (ITS2) ribosomal RNA of nine Coelastrum taxa, Asterarcys quadricellulare (Coelastraceae), Westella botryoides (hitherto Oocystaceae) and Dimorphococcus lunatus (Scenedesmaceae) were determined and compared with existing GenBank entries of scenedesmacean taxa (Desmodesmus, Enallax, Neodesmus, Scenedesmus). Phylogenetic analyses showed that the studied Coelastrum taxa belong to several different lineages within the Scenedesmaceae: five Coelastrum taxa (Coelastrum microporum, Coelastrum astroideum, C. astroideum var. rugosum  =  Coelastrum rugosum, Coelastrum pseudomicroporum and Coelastrum sphaericum incl. Coelastrum proboscideum) form monophyletic clades, whereas two strains labeled Coelastrum morum belong to different genera. The African strain of C. morum clusters with Coelastrum cambricum. The Finnish strain labeled C. morum clusters with Asterarcys, Dimorphococcus and Hariotina. According to its morphology this strain belongs to Coelastrella, related to Coelastrella saiponensis. Westella botryoides belongs to a separate clade within the Scenedesmaceae. Coelastrum reticulatum is positioned in the clade with Asterarcys, Dimorphococcus and Coelastrella; hence its separation in a separate genus, as originally described (Hariotina), is justified. In general, the phylogenetic analysis of ITS2 data shows that the Coelastraceae are included in the monophyletic Scenedesmaceae, and thus the splitting into two families is not justified, but they belong to the monophyletic subfamily Coelastroidea. The genera Comasiella and Pectinodesmus are newly erected, and several new combinations are proposed.






Image of Nostoc....(1) Image of Oscillatoria....(2) Cyanobacteria live in water and they can prepare their own food by photosynthesis. They are the oldest, largest and most important bacteria on the earth. e.g.
(1) Nostoc 
File:Lyngbya.jpgSize of this preview: BIG


Red algae

Image of Red Algae (Image source: http://www.ucmp.berkeley.edu/protista/rhodophyta.html) The red algae look red due to presence of pigment phycoerythrin. These pigments reflect red light and absorb blue light , which penetrates deep into the sea. Some red algae have very little of phycoerythrin so they look blue or greenish due to chlorophyll of some other pigments.
In Asia, Rhodophyta are important source of food. They are rich in Vitamins and protein contents, e.g. nori. They are easy to grow so Japan started growing them more then 300 years ago. Some red algae help in reef-building.
any species of planktonic cyanobacteria possess specialized intracellular gas vesicles. Stacks of these minute (<300 nm) proteinaceous hollow cylinders maintain a gas-filled space in the cell, which enables the organism to regulate its buoyancy and thus to actively seek water depths with optimal growth conditions. However, regulation of buoyancy by changing the amount of gas in the vesicles is slow. Cells adapted to turbulent mixing by enlarged gas vesicles will take a few days to reduce their buoyancy in order to adapt to more quiescent conditions.


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