Effects of inoculated Microcoleus vaginatus on the structure and function of biological soil crusts of desert

2010 ◽  
Vol 47 (4) ◽  
pp. 473-480 ◽  
Author(s):  
Yunpu Zheng ◽  
Ming Xu ◽  
Jiancheng Zhao ◽  
Shuqing Bei ◽  
Lihua Hao
Keyword(s):  
Biological Soil Crusts ◽  
Structure And Function ◽  
Soil Crusts ◽  
Microcoleus Vaginatus ◽  
And Function

scholarly journals Water and Heat-Triggered Changes of Bacterial Community Structure and Function in Biological Soil Crusts

2021 ◽  
Author(s):  
Xiaoting Wei ◽  
Fuwen Qin ◽  
Bing Han ◽  
Huakun Zhou ◽  
Miao Liu ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Aridity Index ◽  
Soil Improvement ◽  
Biological Soil Crusts ◽  
Structure And Function ◽  
Soil Crusts ◽  
And Function

Abstract Background and Aims：The outstanding ability of biological soil crusts (BSCs) in soil microenvironments regulation is mainly attribute to microorganisms that colonizing in biocrusts. We aimed to investigate the changes of bacterial community structure and function with biocrust succession, as well as their responses to climatic changes across large geographical scales.Methods: Algal BSCs and lichen BSCs were sampled along an aridity gradient on alpine grasslands. Bacterial communities in biocrusts were measured using high-throughput sequencing, and soil underlying biocrusts (0-5 cm) was collected for nutrients determination. Results: Our results indicated that compared with algal BSCs, bacterial community in lichen BSCs was characterized by lower diversity, more complex co-occurrence network and mutually beneficial relationships. The bacterial community assembly was governed mainly by stochastic processes for lichen BSCs, which was different from the almost equally important roles of stochastic and deterministic processes for algal BSCs. Geographical location had a significant effect on bacterial communities in both algal and lichen BSCs, while had a greater effect on lichen BSCs. It is noteworthy that the bacterial diversity of algal BSCs was positively correlated with aridity index, while that of lichens was negatively correlated with aridity index. Moreover, we determined lower soil pH and higher soil phosphorus content underlying lichen BSCs, implying their advantages in soil improvement. Conclusions: Aridity index was one of important driving factors of bacterial community in biocrusts, and its effects were biocrust type dependent. Lichen BSCs had greater effects on soil improvement than that of algal BSCs.

scholarly journals Diazotrophic Community Structure and Function in Two Successional Stages of Biological Soil Crusts from the Colorado Plateau and Chihuahuan Desert

2004 ◽  
Vol 70 (2) ◽  
pp. 973-983 ◽  
Author(s):  
Chris M. Yeager ◽  
Jennifer L. Kornosky ◽  
David C. Housman ◽  
Edmund E. Grote ◽  
Jayne Belnap ◽  
...  
Keyword(s):  
Community Structure ◽  
Chihuahuan Desert ◽  
Nitrogenase Activity ◽  
Colorado Plateau ◽  
Biological Soil Crusts ◽  
Rrna Gene ◽  
Soil Crusts ◽  
Clone Sequencing ◽  
Microcoleus Vaginatus ◽  
Diazotrophic Community

ABSTRACT The objective of this study was to characterize the community structure and activity of N2-fixing microorganisms in mature and poorly developed biological soil crusts from both the Colorado Plateau and Chihuahuan Desert. Nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the Colorado Plateau site and Chihuahuan Desert site, respectively. Analysis of nifH sequences by clone sequencing and the terminal restriction fragment length polymorphism technique indicated that the crust diazotrophic community was 80 to 90% heterocystous cyanobacteria most closely related to Nostoc spp. and that the composition of N2-fixing species did not vary significantly between the poorly developed and mature crusts at either site. In contrast, the abundance of nifH sequences was approximately 7.5 times greater (per microgram of total DNA) in mature crusts than in poorly developed crusts at a given site as measured by quantitative PCR. 16S rRNA gene clone sequencing and microscopic analysis of the cyanobacterial community within both crust types demonstrated a transition from a Microcoleus vaginatus-dominated, poorly developed crust to mature crusts harboring a greater percentage of Nostoc and Scytonema spp. We hypothesize that ecological factors, such as soil instability and water stress, may constrain the growth of N2-fixing microorganisms at our study sites and that the transition to a mature, nitrogen-producing crust initially requires bioengineering of the surface microenvironment by Microcoleus vaginatus.

scholarly journals Flux balance modeling to predict bacterial survival during pulsed-activity events

2018 ◽  
Vol 15 (7) ◽  
pp. 2219-2229 ◽  
Author(s):  
Nicholas A. Jose ◽  
Rebecca Lau ◽  
Tami L. Swenson ◽  
Niels Klitgord ◽  
Ferran Garcia-Pichel ◽  
...  
Keyword(s):  
Mass Spectroscopy ◽  
Compatible Solutes ◽  
Soil Microbial Communities ◽  
Metabolic Model ◽  
Biological Soil Crusts ◽  
Arid Environments ◽  
Bacterial Survival ◽  
Flux Balance ◽  
Soil Crusts ◽  
Microcoleus Vaginatus

Abstract. Desert biological soil crusts (BSCs) are cyanobacteria-dominated surface soil microbial communities common to plant interspaces in arid environments. The capability to significantly dampen their metabolism allows them to exist for extended periods in a desiccated dormant state that is highly robust to environmental stresses. However, within minutes of wetting, metabolic functions reboot, maximizing activity during infrequent permissive periods. Microcoleus vaginatus, a primary producer within the crust ecosystem and an early colonizer, initiates crust formation by binding particles in the upper layer of soil via exopolysaccharides, making microbial dominated biological soil crusts highly dependent on the viability of this organism. Previous studies have suggested that biopolymers play a central role in the survival of this organism by powering resuscitation, rapidly forming compatible solutes, and fueling metabolic activity in dark, hydrated conditions. To elucidate the mechanism of this phenomenon and provide a basis for future modeling of BSCs, we developed a manually curated, genome-scale metabolic model of Microcoleus vaginatus (iNJ1153). To validate this model, gas chromatography–mass spectroscopy (GC–MS) and liquid chromatography–mass spectroscopy (LC–MS) were used to characterize the rate of biopolymer accumulation and depletion in in hydrated Microcoleus vaginatus under light and dark conditions. Constraint-based flux balance analysis showed agreement between model predictions and experimental reaction fluxes. A significant amount of consumed carbon and light energy is invested into storage molecules glycogen and polyphosphate, while β-polyhydroxybutyrate may function as a secondary resource. Pseudo-steady-state modeling suggests that glycogen, the primary carbon source with the fastest depletion rate, will be exhausted if M. vaginatus experiences dark wetting events 4 times longer than light wetting events.

scholarly journals Flux balance modelling to predict bacterial survival during pulsed activity events

2017 ◽  
Author(s):  
Nicholas A. Jose ◽  
Rebecca Lau ◽  
Tami L. Swenson ◽  
Niels Klitgord ◽  
Ferran Garcia-Pichel ◽  
...  
Keyword(s):  
Compatible Solutes ◽  
Soil Microbial Communities ◽  
Metabolic Model ◽  
Biological Soil Crusts ◽  
Arid Environments ◽  
Bacterial Survival ◽  
Soil Microbial ◽  
Flux Balance ◽  
Soil Crusts ◽  
Microcoleus Vaginatus

Abstract. Desert biological soil crusts (BSCs) are cyanobacteria-dominated, surface soil microbial communities common to plant interspaces in arid environments. The capability to significantly dampen their metabolism allows them to exist for extended periods in a desiccated dormant state that is highly robust to environmental stresses. However, within minutes of wetting, metabolic functions reboot, maximizing activity during infrequent permissive periods. Microcoleus vaginatus, a primary producer within the crust ecosystem and an early colonizer, initiates crust formation by binding particles in the upper layer of soil via exopolysaccharides, making microbial dominated biological soil crusts highly dependent on the viability of this organism. Previous studies have suggested that biopolymers play a central role in the survival of this organism by powering resuscitation, rapidly forming compatible solutes and fuelling metabolic activity in dark, hydrated conditions. To elucidate the mechanism of this phenomenon and provide a basis for future modelling of BSCs, we developed a manually-curated, genome-scale metabolic model of Microcoleus vaginatus (iNJ1153). To validate this model, GC/MS and LC/MS were used to characterize the rate of biopolymer accumulation and depletion in in hydrated Microcoleus vaginatus under light and dark conditions. Constraint-based flux balance analysis showed agreement between model predictions and experimental reaction fluxes. A significant amount of consumed carbon and light energy is invested into storage molecules glycogen and polyphosphate, while β-polyhydroxybutyrate may function as a secondary resource. Pseudo-steady state modelling suggests that glycogen, the primary carbon source with the fastest depletion rate, will be exhausted if M. vaginatus experiences dark wetting events four times longer than light wetting events.

Structure and function of biological soil crusts from Antarctica with a special respect to their microtopography and UV-B sensitivity

2019 ◽  
Vol 9 (2) ◽  
pp. 243-250
Author(s):  
Kateřina Trnková ◽  
Nele Tschense
Keyword(s):  
Biological Soil Crusts ◽  
Quantum Yields ◽  
Professional Literature ◽  
Fine Grained ◽  
Soil Crusts ◽  
Acclimatory Response ◽  
James Ross Island ◽  
Special Respect ◽  
And Function

Although an extensive professional literature exists on biological soil crusts (BSCs), especially on the species composition of hetero- and autotrophs forming the micro-biological comunity, micromorphological information on BSCs is extremely scarce. In our study, we focused on microstructure of the BSCs from the James Ross Island (Antarctica). We combined the approach of digital microscopy to study surface roughness of the BSCs with taxonomy of BSC-forming autotrophs and chlorophyll fluorescence study focused on the photosynthetic functioning of BSCs when exposed to controlled UV-B stress. Microprofiling of BSCs resulted in the finding that the examined BSCs might be classified as fine-grained surface with roughness characteristics: Ra (37.9 μm) and Rz (136.9 μm). The BSCs were rich in microautotrophs, both algae and cyanobacteria, however, Microcoleus sp. was found dominating species. It formed multifilament ropes on and inside the BSCs. Under UV-B stress, Microcoleus- and Nostoc-dominated BSC parts showed similar sensitivity and acclimatory response so long-term UV-B treatment, however, Microcoleus seemed to be slightly more sensitive to UV-B. Microcoleus-dominated parts of BSCs showed less pronounced acclimation to UV-B treatment than Nostoc-dominated parts. It was reflected in lower values of maximum (FV/FM) and effective (FPSII) quantum yields recorded after 6 d exposition.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

Use of human autoantibodies and immunoelectron microscopy to study structure and function of the nucleolus and nuclear bodies

1992 ◽  
Vol 50 (1) ◽  
pp. 506-507
Author(s):  
Robert L. Ochs
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
Nuclear Bodies ◽  
Nuclear Interior ◽  
Coiled Bodies ◽  
Interchromatin Granules ◽  
And Function ◽  
Conventional Electron Microscopy ◽  
Perichromatin Granules ◽  
Perichromatin Fibrils

By conventional electron microscopy, the formed elements of the nuclear interior include the nucleolus, chromatin, interchromatin granules, perichromatin granules, perichromatin fibrils, and various types of nuclear bodies (Figs. 1a-c). Of these structures, all have been reasonably well characterized structurally and functionally except for nuclear bodies. The most common types of nuclear bodies are simple nuclear bodies and coiled bodies (Figs. 1a,c). Since nuclear bodies are small in size (0.2-1.0 μm in diameter) and infrequent in number, they are often overlooked or simply not observed in any random thin section. The rat liver hepatocyte in Fig. 1b is a case in point. Historically, nuclear bodies are more prominent in hyperactive cells, they often occur in proximity to nucleoli (Fig. 1c), and sometimes they are observed to “bud off” from the nucleolar surface.

Depletion and Reconstitution of Active E. Coli Ribosomes

1975 ◽  
Vol 33 ◽  
pp. 640-641
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Protein Biosynthesis ◽  
Large Subunit ◽  
High Resolution Electron Microscopy ◽  
Small Subunit ◽  
Structure And Function ◽  
Biologically Active ◽  
Biological Macromolecules ◽  
E Coli ◽  
Resolution Electron ◽  
And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

Sign in / Sign up

Export Citation Format

Share Document