Biology Reference
In-Depth Information
blooms to a small overwintering population of vegetative cells besides germinating akinetes from
the sediment of a mesotrophic lake. Due to the absence of vegetative fi laments of
A
.
fl os-aquae
in the
water column during winter, Baker (1999) concluded that the bloom originated from the germinating
akinetes from the sediments. This was further confi rmed in case of bloom formation by
A
.
circinalis
in the lower Murray River, Australia by Baker and Bellifemine (2000) who identifi ed temperature,
salinity and desiccation as parameters for potential management strategies to control germination
of akinetes. The average density of
Anabaena
ucrainica
akinetes was found to be 1.5 x 10
4
cm
-3
in
the sediments of a small agricultural reservoir situated in Shiga Prefecture, Japan and constituted
an important source for bloom development as the high germination rates of akinetes was found
in between 14 to 23ºC (Tsujimura and Okubo, 2003). Tsujimura (2004) proposed sediment drying
as a means of reducing the germination frequency to prevent recurrence of blooms of
A
.
ucrainica
.
In the establishment of blooms of
G
.
echinulata
light, temperature, sediment mixing and sediment
origin have been reported to be important factors that affected germination of akinetes. Akinetes
from shallow sediments contributed more to the population rather than from deep water sediments
(Karlsson-Elfgren
et al
., 2004). A count of akinetes with empty envelopes along the littoral region as
well as at the deep water portion of a pond Bugach near Krasnoyarsk, Russia revealed that it is the
akinetes present in the littoral zone fi rst germinated and contributed to the early bloom population of
A
.
fl os-aquae
(Kravchuk
et al
., 2002). Similar spatial and vertical distribution and seasonal dynamics
in the bloom populations of
A
.
fl os-aquae
due to akinetes in the sediments of littoral region and their
germination has been found in a Siberian reservoir (Kravchuk
et al
., 2011).
LITERATURE CITED
Adams, D. G., and Carr, N. G. (1981) The developmental biology of heterocyst and akinete formation in cyanobacteria.
Crit
Rev Microbiol
9:
45
-
100.
Adams, D. G., and Duggan, P. S. (1999) Heterocyst and akinete differentiation in cyanobacteria.
New Phytol
144:
1-33.
Agrawal, S. C., and Singh, V. (2000) Vegetative survival, akinete formation and
germination in three blue-green algae and
one green alga in relation to light intensity,
temperature, heat shock and UV exposure.
Folia Microbiol
45:
439
-
446.
Ahluwalia, A. S., and Kumar, H. D. (1982) Cellular differentiation and nitrogenase activity in the cyanobacterium
Anabaena
.
Beitr Biol Pfl anzen
57:
459-467.
Ahluwalia, A. S., and Kumar, H. D. (1983) Pattern of akinete differentiation in the blue-green alga
Nostoc
sp.
Beitr Biol Pfl anzen
57:
459
-
467.
Ahuja, G., Khattar, J. I. S., and Sarma, T. A. (2008) Interaction between carbon and nitrogen metabolism during akinete
development in the cyanobacterium
Anabaena torulosa
.
J Basic Microbiol
48:
125-129.
Argueta, C., and Summers, M. L. (2005) Characterization of a model system for the study
of
Nostoc punctiforme
akinetes.
Arch Microbiol
183:
338-346.
Argueta, C., Yuksek, K., and Summers, M. L. (2004) Construction and use of GFP
reporter vectors for analysis of cell-type-
specifi c gene expression in
Nostoc punctiforme
.
J Microbiol Methods
59:
181-188.
Argueta, C., Yuksek, K., Patel, R., and Summers, M. L. (2006) Identifi cation of
Nostoc punctiforme
akinete-expressed genes
using differential display.
Mol Microbiol
61:
748-757.
Baker, P. D. (1999) Role of akinetes in the development of cyanobacterial populations in
the lower Murray River, Australia.
Mar Freshwater
Res
50:
265-279.
Baker, P. D., and Bellifemine, D. (2000) Environmental infl uences on akinete
germination of
Anabaena circinalis
and implications
for management of
cyanobacterial blooms.
Hydrobiologia
427:
65
-
73.
Braune, W. (1979) C-phycocyanin—the main photoreceptor in the light-dependent
germination process
of Anabaena
akinetes.
Arch Microbiol
122:
289
-
295.
Braune, W. (1980) Structural aspects of akinete germination in the cyanobacterium
Anabaena variabilis
.
Arch Microbiol
126:
257
-
261.
Burger, J. (1974) A study of two populations of
Anabaena planctonica
Brunnth.
(Cyanophyta) from Minnesota.
Phycologia
13:
125
-
129.
