Structure and function of traditional agroforestry systems in the western Himalaya. II. Nutrient cycling

1989 ◽  
Vol 9 (1) ◽  
pp. 71-89 ◽  
Author(s):  
Om Parkash Toky ◽  
Pradeep Kumar ◽  
Prem Kumar Khosla
Keyword(s):  
Nutrient Cycling ◽  
Western Himalaya ◽  
Agroforestry Systems ◽  
Structure And Function ◽  
Traditional Agroforestry ◽  
And Function

Gill microbiome structure and function in the chemosymbiotic coastal lucinid Stewartia floridana

2021 ◽  
Author(s):  
Shen Jean Lim ◽  
Brenton Davis ◽  
Danielle Gill ◽  
John Swetenburg ◽  
Laurie C Anderson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nutrient Cycling ◽  
Bacterial Communities ◽  
Structure And Function ◽  
Differentially Expressed ◽  
Seagrass Species ◽  
Bare Sand ◽  
And Function

Abstract Lucinid bivalves harbor environmentally acquired, chemosynthetic, gammaproteobacterial gill endosymbionts. Lucinid gill microbiomes, which may contain other gammaproteobacterial and/or spirochete taxa, remain under-sampled. To understand inter-host variability of the lucinid gill microbiome, specifically in the bacterial communities, we analyzed the microbiome content of Stewartia floridana collected from Florida. Sampled gills contained a monospecific gammaproteobacterial endosymbiont expressing lithoautotrophic, mixotrophic, diazotrophic, and C1 compound oxidation-related functions previously characterized in similar lucinid species. Another low-abundance Spirochaeta-like species in ∼72% of the sampled gills was most closely related to Spirochaeta-like species in another lucinid Phacoides pectinatus and formed a clade with known marine Spirochaeta symbionts. The spirochete expressed genes were involved in heterotrophy and the transport of sugars, amino acids, peptides, and other substrates. Few muscular and neurofilament genes from the host and none from the gammaproteobacterial and spirochete symbionts were differentially expressed among quadrats predominantly covered with seagrass species or 80% bare sand. Our results suggest that spirochetes are facultatively associated with S. floridana, with potential scavenging and nutrient cycling roles. Expressed stress- and defense-related functions in the host and symbionts also suggest species-species communications, which highlight the need for further study of the interactions among lucinid hosts, their microbiomes, and their environment.

Cacao, Shade, and Agroforestry

2021 ◽  
pp. 138-145
Author(s):  
Dale Walters
Keyword(s):  
Natural Habitat ◽  
Disease Outbreaks ◽  
Agroforestry Systems ◽  
Structure And Function ◽  
Native Forest ◽  
Shade Trees ◽  
Forest Trees ◽  
And Function ◽  
Trees And Shrubs

In its natural habitat, cacao grows in the shade of larger trees. In fact, 70 percent of the world’s cacao is grown with some level of shade. This comes mostly from native forest trees, thinned out to provide space for cacao seedlings to be planted, or to a lesser extent, from trees specially planted to provide shade. This mixture of shade trees and shrubs creates a three-tier canopy, resulting in a multi-species system similar in structure and function to a forest, known as an agroforest. Cacao agroforestry systems include full-sun cacao, diversified-shade cacao, and specialized-shade cacao. Achieving an appropriate level of shading for cacao is important, since it affects yield and can influence pest and disease outbreaks. Shade in cacao also helps to maintain biodiversity, so getting shade right in cacao agroforestry is important. This chapter examines the benefits and problems associated with growing cacao with and without shade.

scholarly journals Insights into the soil microbiome and prospects for its manipulation for improved pasture resilience

2021 ◽  
Vol 17 ◽  
Author(s):  
Maureen O'Callaghan ◽  
Shengjing Shi ◽  
Sean Marshall ◽  
Nicole Schon ◽  
Bryony Dignam ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Structure And Function ◽  
Molecular Techniques ◽  
Disease Suppression ◽  
Soil Microbiome ◽  
Soil Functions ◽  
Plant Pest ◽  
And Function ◽  
Improved Pasture

• The soil microbiome refers to the diverse collection of microorganisms present in soil, many of which can mediate essential soil functions such as nutrient cycling and plant pest and disease suppression. • There is growing international interest in the potential to manipulate the soil microbiome to deliver improved agricultural and environmental outcomes. • Molecular techniques are rapidly increasing understanding of the soil microbiome structure and function but manipulating soil microbiomes for pasture resilience still presents significant science challenges.

Fish in the Structure and Function of Freshwater Ecosystems: A "Top-down" View

1988 ◽  
Vol 45 (2) ◽  
pp. 361-379 ◽  
Author(s):  
T. G. Northcote
Keyword(s):  
Nutrient Cycling ◽  
Feeding Activity ◽  
Freshwater Ecosystems ◽  
Structure And Function ◽  
Prey Selectivity ◽  
Top Down ◽  
Selective Predation ◽  
German Research ◽  
And Function

The role of fish in regulation of the structure and function of freshwater ecosystems (lakes and streams) is examined with respect to effects resulting directly from their feeding activity, indirectly from size or other forms of prey selectivity, and from influences on nutrient cycling and transport. That fish have long had a legitimate place in limnological research is documented by a review of limnological books, texts, and journals. Recognition of their "top-down" effects, started largely from Czechoslovakian research (Hrbáček and others) in the mid-1950's, was popularized by American and German research (Brooks, Jacobs, and others) in the mid-1960's and has enjoyed a remarkable upsurge in the 1970's, continuing into the 1980's. Although size-selective predation has been an important phenomenon in stimulating widespread research on effects of fish on freshwater communities and their function, the importance of other mechanisms in such regulation is considered.

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.

Sign in / Sign up

Export Citation Format

Share Document