Ohmori, The pknH gene restrictively expressed in heterocysts
is required for diazotrophic growth in the cyanobacterium Anabaena sp.
(b) Intraoperative frozen pathology of thyroid isthmus: red arrow for heterocyst
; blue arrow for psammoma body; green arrow for papillary structure.
(MBFG VII) to filaments with heterocyst
, Anabaena circinalis and Aphanizomenon flos-aquae (MBFG III), with subsequent prevalence of filamentous species without heterocyst
, Planktothrix agardhii and Geitlerinema splendidum, when there is an increase in ammoniacal nitrogen concentrations.
It is represented by free floating trichomes with heterocysts
intercalated and akinetes (Van Geel et al., 1994; Komarek & Komarkova-Legnerova, 2002).
Within an hour, these cells could be seen attached to heterocysts
in the same manner as in the two-membered culture (Fig.
There is some debate whether the presence of heterocysts
The presence of heterocysts
indicate that five of the cyanobacterial species potentially fix [N.sub.2].
in this genus ability of gliding motility and lake of heterocysts
and akinetes are not formed.
Furthermore, some species have developed the ability to fix nitrogen through specialized cells called heterocysts
(Wehr and Sheath, 2003).
Approximately 10 Anabaena species were identified in the fresh material; however, establishing the dominant species when counting was difficult, as frequently only pieces of filaments without akinetes and heterocysts
were found in the counting chamber.
were estimated using an inverted microscope and Sedgwick-Rafter counting chamber.
Some cyanobacterial genera can fix nitrogen in specialized cells called heterocysts
, which form a monophyletic lineage.