|
 |
|
| |
|
Abstracts
of Recent Publications |
|
001-
Noah Fierer, Zongzhi Liu, Mari Rodríguez-Hernández,
Rob Knight, Matthew Henn, Mark T. Hernandez. University
of Colorado, 216 UCB, CIRES, Boulder, CO 80309-0216.
Short-Term Temporal Variability in Airborne
Bacterial and Fungal Populations. Applied
and Environmental Microbiology, 74,
2008, 200-207.
Airborne microorganisms have been studied for
centuries, but the majority of this research has
relied on cultivation-dependent surveys that may
not capture all of the microbial diversity in
the atmosphere. As a result, our understanding
of airborne microbial ecology is limited despite
the relevance of airborne microbes to human health,
various ecosystem functions, and environmental
quality.
Cultivation-independent surveys
of small-subunit rRNA genes were conducted in
order to identify the types of airborne bacteria
and fungi found at a single site (Boulder, CO)
and the temporal variability in the microbial
assemblages over an 8-day period. We found that
the air samples were dominated by ascomycete fungi
of the Hypocreales order and a diverse
array of bacteria, including members of the proteobacterial
and Cytophaga-Flavobacterium-Bacteroides
groups that are commonly found in comparable culture-independent
surveys of airborne bacteria. Bacterium/fungus
ratios varied by 2 orders of magnitude over the
sampling period, and we observed large shifts
in the phylogenetic diversity of bacteria present
in the air samples collected on different dates,
shifts that were not likely to be related to local
meteorological conditions. We observed more phylogenetic
similarity between bacteria collected from geographically
distant sites than between bacteria collected
from the same site on different days. These results
suggest that outdoor air may harbor similar types
of bacteria regardless of location and that the
short-term temporal variability in airborne bacterial
assemblages can be very large.
Keywords:Airborne
Bacterial, Fungal Populations, Airborne microorganisms,
airborne microbes, Hypocreales.
|
|
002-Luis
David Alcaraz, Gabriela Olmedo, Germán
Bonilla, René Cerritos, Gustavo Hernández,
Alfredo Cruz, Enrique Ramírez, Catherine
Putonti, Beatriz Jiménez, Eva Martínez,
Varinia López, Jacqueline L. Arvizu, Francisco
Ayala, Francisco Razo, Juan Caballero, Janet Siefert,
Luis Eguiarte, Jean-Philippe Vielle, Octavio Martínez,
Valeria Souza, Alfredo Herrera-Estrella, Luis
Herrera-Estrella.The genome of Bacillus
coahuilensis reveals adaptations essential
for survival in the relic of an ancient marine
environment. PNAS, 105,
2008, 5803-5808.
The Cuatro Ciénegas Basin (CCB) in the
central part of the Chihuahan desert (Coahuila,
Mexico) hosts a wide diversity of microorganisms
contained within springs thought to be geomorphological
relics of an ancient sea. A major question remaining
to be answered is whether bacteria from CCB are
ancient marine bacteria that adapted to an oligotrophic
system poor in NaCl, rich in sulfates, and with
extremely low phosphorus levels (<0.3 µM).
Here, we report the complete genome sequence of
Bacillus coahuilensis, a sporulating
bacterium isolated from the water column of a
desiccation lagoon in CCB. At 3.35 Megabases this
is the smallest genome sequenced to date of a
Bacillus species and provides insights
into the origin, evolution, and adaptation of
B. coahuilensis to the CCB environment. We propose
that the size and complexity of the B. coahuilensis
genome reflects the adaptation of an ancient marine
bacterium to a novel environment, providing support
to a "marine isolation origin hypothesis"
that is consistent with the geology of CCB. This
genomic adaptation includes the acquisition through
horizontal gene transfer of genes involved in
phosphorous utilization efficiency and adaptation
to high-light environments. The B. coahuilensis
genome sequence also revealed important ecological
features of the bacterial community in CCB and
offers opportunities for a unique glimpse of a
microbe-dominated world last seen in the Precambrian.
Keywords:
evolution, enomic adaptation, horizontal, gene transfer,
phosphorus stress, sulfolipids, B. coahuilensis.
|
003-
Virginia H. Dale, Aaron D. Peacock , Charles T.
Garten Jr, Edward Sobek, Amy K. Wolfe. Environmental
Sciences Division, Oak Ridge National Laboratory,
Oak Ridge, TN 37831, USA. Selecting indicators
of soil, microbial, and plant conditions to understand
ecological changes in Georgia pine forests.
Ecological Indicators, 8, 2008,
818-827.
Characterizing how resource use and management
activities affect ecological conditions is necessary
to document and understand anthropogenic changes
in ecological systems. Resource managers on military
installations have the delicate task of balancing
the training needs of soldiers effectively with
the need to maintain a high quality of ecological
conditions. This study considers ways that ecological
indicators can provide information on impacts
that training has on environmental characteristics
that occur at different scales and in different
sectors of the environment. The characteristics
examined include soil chemistry, soil microbes,
and vegetation. A discriminant function analysis
was conducted to determine whether ecological
indicators could differentiate among different
levels of military use. A combination of 10 indicators
explained 90% of the variation among plots from
five different military use levels. Results indicated
that an appropriate suite of ecological indicators
for military resource managers includes soil,
microbial, and vegetation characteristics. Since
many of these indicators are related, managers
at this location potentially have freedom to choose
indicators that are relatively easy to measure,
without sacrificing information.
Keywords: Indicators
of soil, Georgia pine forests, soil microbes,
microbial, ecological changes.
|
004-Yu-Hong
Su, Yong-Guan Zhu. Research Center for Eco-environmental
Sciences, Chinese Academy of Sciences, 18 Shuangqing
Road, Beijing 100085, China. Uptake of
selected PAHs from contaminated soils by rice
seedlings (Oryza sativa) and influence
of rhizosphere on PAH distribution. Environmental
Pollution, 155, 2008, 359-365.
The uptake of selected polycyclic aromatic hydrocarbons
(PAHs) by rice ( Oryza sativa) seedlings
from spiked aged soils was investigated.When applied
to soils aged for 4 months, naphthalene, phenanthrene,
and pyrene exhibited volatilization loss of 98,
95, and 30%, respectively,with the remaining fraction
being fixed by soil organic matter and/or degraded
by soil microbes. In general, concentrations of
the three PAHs in rice roots were greater than
those in the shoots. The concentrations of root
associated PHN and PYR increased proportionally
with both soil solution and rhizosphere concentrations.
PAH concentrations in shoots were largely independent
of those in soil solution, rice roots, or rhizosphere
soil. The relative contributions of plant uptake
and plant-promoted rhizosphere microbial biodegradation
to the total mass balance were 0.24 and 14%, respectively,
based on PYR concentrations in rhizosphere and
non-rhizosphere soils, the biomass of rice roots,
and the dry soil weight.
Keywords:PAHs;
Rice ( Oryza sativa); Uptake; Rhizosphere
effect; Aged soil.
|
|
| ENVIS
CENTRE Newsletter Vol.7,Issue 1 January 2009 |
Back |
|
|
|
|
| |
|
|
