Consumption and Decomposition of Lichen Litter in a Temperate Coniferous Rainforest

1994 ◽  
Vol 26 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Bruce McCune ◽  
William J. Daly
Keyword(s):  
Weight Loss ◽  
Half Life ◽  
Significant Contribution ◽  
Mesh Size ◽  
Litter Bags ◽  
Nylon Mesh ◽  
Alectoria Sarmentosa ◽  
Lobaria Oregana ◽  
Rate Of Consumption

AbstractNylon mesh litter–bags markedly reduced the rate of weight loss of lichen litter, as compared to unconfined (free) lichens, suggesting that herbivores and detritivores larger than the mesh size make a significant contribution to the disappearance of lichen litter. The half–life of free lichen litter was 1·5 months for Alectoria sarmentosa, 2·5 months for Hypogymnia inactiva, 3·5 months for Platismatia glauca, and 7 months for Lobaria oregana. The half–lives were 2·9 times longer for the same species in litter–bags. Because A. sarmentosa showed the greatest difference between free litter and litter–bags, we conclude that, of the four species studied, it had the highest rate of consumption by larger herbivores and detritivores.

scholarly journals Post-fire consequences for leaf breakdown in a tropical stream

2019 ◽  
Vol 31 ◽  
Author(s):  
Renan de Souza Rezende ◽  
Cristiano Queiroz de Albuquerque ◽  
Andrezza Sayuri Victoriano Hirota ◽  
Paulo Fernandes Roges Souza Silva ◽  
Ricardo Keichi Umetsu ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Fungal Biomass ◽  
Mesh Size ◽  
Fire Effects ◽  
Dry Mass ◽  
Tropical Stream ◽  
Fire Event ◽  
Litter Bags ◽  
Fine Mesh ◽  
Post Fire Effects

Abstract Aim Wildfire is a natural pulsed disturbance in landscapes of the Savannah Biome. This study evaluates short-term post-fire effects on leaf litter breakdown, the invertebrate community and fungal biomass of litter from three different vegetal species in a tropical stream. Methods Senescent leaves of Inga laurina, Protium spruceanum and Rircheria grandis (2 ± 0.1 g dry mass) were individually placed in litter bags (30 × 30 cm: 10 mm coarse mesh and 0.5 mm fine mesh) and submerged in the study stream before and after fire. Replicate bags (n = 4; individually for each species, sampling time, fire event and mesh size) were then retrieved after 20 and 40 days and washed to separate the invertebrates before fire event and again immediately after fire. Disks were cut from leaves to determine ash-free dry mass, while the remaining material was oven-dried to determine dry mass. Results The pre-fire mean decomposition coefficient (k = -0.012 day-1) was intermediate compared to that reported for other savannah streams, but post-fire it was lower (k = -0.007 day-1), due to decreased allochthonous litter input and increased autochthones production. Intermediate k values for all qualities of litter post-fire may indicate that fire is equalizing litter quality in the stream ecosystem. The abundance of scrapers was found to be more important than fungal biomass or shredder abundance, probably due to their functioning in leaf fragmentation while consuming periphyton growing on leaf litter. Conclusions Theses results indicate that fire can modify the relationships within decomposer communities in tropical stream ecosystems.

scholarly journals Molecular mechanisms facilitating the initial kinetochore encounter with spindle microtubules

2017 ◽  
Vol 216 (6) ◽  
pp. 1609-1622 ◽  
Author(s):  
Vanya Vasileva ◽  
Marek Gierlinski ◽  
Zuojun Yue ◽  
Nicola O’Reilly ◽  
Etsushi Kitamura ◽  
...  
Keyword(s):  
Half Life ◽  
Molecular Mechanisms ◽  
Significant Contribution ◽  
Budding Yeast ◽  
Computational Simulation ◽  
Spindle Microtubule ◽  
Multiple Factors ◽  
Spindle Microtubules ◽  
Rate Limiting

The initial kinetochore (KT) encounter with a spindle microtubule (MT; KT capture) is one of the rate-limiting steps in establishing proper KT–MT interaction during mitosis. KT capture is facilitated by multiple factors, such as MT extension in various directions, KT diffusion, and MT pivoting. In addition, KTs generate short MTs, which subsequently interact with a spindle MT. KT-derived MTs may facilitate KT capture, but their contribution is elusive. In this study, we find that Stu1 recruits Stu2 to budding yeast KTs, which promotes MT generation there. By removing Stu2 specifically from KTs, we show that KT-derived MTs shorten the half-life of noncaptured KTs from 48–49 s to 28–34 s. Using computational simulation, we found that multiple factors facilitate KT capture redundantly or synergistically. In particular, KT-derived MTs play important roles both by making a significant contribution on their own and by synergistically enhancing the effects of KT diffusion and MT pivoting. Our study reveals fundamental mechanisms facilitating the initial KT encounter with spindle MTs.

scholarly journals DECOMPOSITION OF LEAF LITTER IN THE BRAZILIAN CERRADO, CERRADÃO AND FOREST ENVIRONMENTS IN THE AMAZON, BRAZIL

FLORESTA ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 803
Author(s):  
Maria Clécia Gomes Sales ◽  
Milton César Costa Campos ◽  
Elilson Gomes de Brito Filho ◽  
Luís Antônio Coutrim Dos Santos ◽  
José Maurício Da Cunha ◽  
...  
Keyword(s):  
Litter Decomposition ◽  
Half Life ◽  
Life Time ◽  
Dry Mass ◽  
Nutrient Input ◽  
Decomposition Rates ◽  
Mass Percentage ◽  
Litter Bags ◽  
Litter Bag ◽  
Loss Analysis

The soils of the Amazon region, despite being under one of the densest forests in the world, are mostly characterized by low nutrient availability, with litter being the main nutrient input route. The present work aimed to evaluate the litter decomposition in forest, Cerrado and Cerradão environments in the Amazon. The litter decomposition rate was estimated by mass loss analysis using litter bags. The collections were performed at intervals of 30, 60, 90, 120, 150, 180, 210, 240, 270 and 300 days, with four replications. Once collected, the material contained in each litter bag was placed to dry to obtain the dry mass. And so, the remaining mass percentage, the decomposition rates (k) and the half-life time (t1/2) are estimated. During the studied period, the Cerrado environment presented the lowest constant k (0.0017 g g-1 day-1) and consequently longer half-life (407 days). The monthly deposition in Cerrado input ranged from Mgha-1mother1 (June to September). Among the evaluated environments, the forest presented the highest decomposition speed and Cerrado presented the lowest one. It was evidenced that the decomposition process for all studied environments occurred with greater intensity in the rainy season.

scholarly journals The effect of fatty diacid acylation of human PYY3-36 on Y2 receptor potency and half-life in minipigs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Søren Østergaard ◽  
Johan F. Paulsson ◽  
Jacob Kofoed ◽  
Franziska Zosel ◽  
Jørgen Olsen ◽  
...  
Keyword(s):  
Weight Loss ◽  
Fatty Acid ◽  
Serum Albumin ◽  
Half Life ◽  
Backbone Cleavage ◽  
Dosing Regimen ◽  
High Potency ◽  
Additional Weight ◽  
Proteolytic Stability

AbstractPeptides are notoriously known to display very short in vivo half-lives often measured in minutes which in many cases greatly reduces or eliminates sufficient in vivo efficacy. To obtain long half-lives allowing for up to once-weekly dosing regimen, fatty acid acylation (lipidation) have been used to non-covalently associate the peptide to serum albumin thus serving as a circulating depot. This approach is generally considered in the scientific and patent community as a standard approach to protract almost any given peptide. However, it is not trivial to prolong the half-life of peptides by lipidation and still maintain high potency and good formulation properties. Here we show that attaching a fatty acid to the obesity-drug relevant peptide PYY3-36 is not sufficient for long pharmacokinetics (PK), since the position in the backbone, but also type of fatty acid and linker strongly influences PK and potency. Furthermore, understanding the proteolytic stability of the backbone is key to obtain long half-lives by lipidation, since backbone cleavage still occurs while associated to albumin. Having identified a PYY analogue with a sufficient half-life, we show that in combination with a GLP-1 analogue, liraglutide, additional weight loss can be achieved in the obese minipig model.

scholarly journals Carbon and nitrogen cycling in an integrated soybean-beef cattle production system under different grazing intensities

2015 ◽  
Vol 50 (10) ◽  
pp. 967-978 ◽  
Author(s):  
Joice Mari Assmann ◽  
Ibanor Anghinoni ◽  
Amanda Posselt Martins ◽  
Sérgio Ely Valadão Gigante de Andrade Costa ◽  
Taise Robinson Kunrath ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Dry Matter ◽  
Grazing Intensity ◽  
Italian Ryegrass ◽  
Release Rates ◽  
Litter Bags ◽  
Nylon Mesh ◽  
N Release ◽  
Grazing Intensities ◽  
C And N

Abstract:The objective of this work was to evaluate the effect of grazing intensity on the decomposition of cover crop pasture, dung, and soybean residues, as well as the C and N release rates from these residues in a long-term integrated soybean-beef cattle system under no-tillage. The experiment was initiated in 2001, with soybean cultivated in summer and black oat + Italian ryegrass in winter. The treatments consisted of four sward heights (10, 20, 30, and 40 cm), plus an ungrazed area, as the control. In 2009-2011, residues from pasture, dung, and soybean stems and leaves were placed in nylon-mesh litter bags and allowed to decompose for up to 258 days. With increasing grazing intensity, residual dry matter of the pasture decreased and that of dung increased. Pasture and dung lignin concentrations and C release rates were lower with moderate grazing intensity. C and N release rates from soybean residues are not affected by grazing intensity. The moderate grazing intensity produces higher quality residues, both for pasture and dung. Total C and N release is influenced by the greater residual dry matter produced when pastures were either lightly grazed or ungrazed.

scholarly journals Fc-GDF15 glyco-engineering and receptor binding affinity optimization for body weight regulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ella Fung ◽  
Liya Kang ◽  
Diana Sapashnik ◽  
Susan Benard ◽  
Annette Sievers ◽  
...  
Keyword(s):  
Weight Loss ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Half Life ◽  
Metabolic Diseases ◽  
Single Point ◽  
Life Extension ◽  
Single Point Mutation ◽  
Receptor Binding Site

AbstractGDF15 is a distant TGF-β family member that induces anorexia and weight loss. Due to its function, GDF15 has attracted attention as a potential therapeutic for the treatment of obesity and its associated metabolic diseases. However, the pharmacokinetic and physicochemical properties of GDF15 present several challenges for its development as a therapeutic, including a short half-life, high aggregation propensity, and protease susceptibility in serum. Here, we report the design, characterization and optimization of GDF15 in an Fc-fusion protein format with improved therapeutic properties. Using a structure-based engineering approach, we combined knob-into-hole Fc technology and N-linked glycosylation site mutagenesis for half-life extension, improved solubility and protease resistance. In addition, we identified a set of mutations at the receptor binding site of GDF15 that show increased GFRAL binding affinity and led to significant half-life extension. We also identified a single point mutation that increases p-ERK signaling activity and results in improved weight loss efficacy in vivo. Taken together, our findings allowed us to develop GDF15 in a new therapeutic format that demonstrates better efficacy and potential for improved manufacturability.

Effects of fenitrothion and adjuvants on the decomposition rate of white spruce foliage in litter bags on the forest floor

1985 ◽  
Vol 15 (1) ◽  
pp. 174-176
Author(s):  
D. C. Eidt ◽  
C. A. A. Weaver
Keyword(s):  
Weight Loss ◽  
Decomposition Rate ◽  
Forest Floor ◽  
Emission Rate ◽  
White Spruce ◽  
Litter Bags ◽  
Water Based

Fenitrothion in oil and water-based formulations at the conventional aerial emission rate and 10 times that rate, and adjuvants alone at 10 times the aerial emission rate, had no effect on the decomposition rate of white spruce foliage, as indicated by weight loss.

Resistance to Extinction as a Function of Shifts in Incentive

1971 ◽  
Vol 29 (1) ◽  
pp. 175-179
Author(s):  
Melvin H. Marx
Keyword(s):  
Weight Loss ◽  
Significant Contribution ◽  
Extinction Test ◽  
Group Differences ◽  
Initial Part ◽  
Resistance To Extinction ◽  
Sucrose Reinforcement

Rats given magazine and bar-press training with 32% sucrose reinforcement learned faster than those given either 4% or 11% reinforcements. After all Ss were given a small, decreasing number of 11% reinforcements as the initial part of an extinction test, reliable group differences occurred, the downshifted Ss showing the greatest and the upshifted Ss the least decrement in nonreinforced performance. The results are interpreted as supporting the reality of an over-all contrast phenomenon, especially with respect to the recently implicated artifactual account emphasizing differential weight loss but as leaving open the question of whether any significant contribution is made by an overshooting effect.

Decomposition and nutrient release in Douglas-fir needle litter in relation to stand development

1979 ◽  
Vol 9 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Robert L. Edmonds
Keyword(s):  
Weight Loss ◽  
Nutrient Release ◽  
Nutrient Content ◽  
Douglas Fir ◽  
Strongly Correlated ◽  
Litter Bags ◽  
Net Productivity ◽  
Needle Litter ◽  
Weight Loss Data ◽  
Moisture Conditions

Decomposition rates and changes in the nutrient content of needle litter were examined in an age sequence of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Washington. The stands at the initiation of the study were 11, 24, 44, 75, and 97 years old. Nylon litter bags (1 mm mesh) containing needles from the 44-year-old stand were placed in the stands in February 1975. Bags were collected after 3, 6, 12, and 24 months, weighed, and analyzed for N, P, K, Ca, Mg, Mn, and lignin. Decomposition constants (k values) were determined. After 2 years, maximum decomposition rate occurred in the 24-year-old stand, where temperature and moisture conditions were most favorable. Low litter moisture tended to inhibit decomposition in summer. Values of k determined from 1-year weight loss data and percent needle lignin after 2 years were significantly different between stands. Values of k determined from weight loss were greater than those determined from litter fall weight: forest floor weight ratios. Loss of elements from litter bags after 2 years was in the following sequence in all stands, N < Mn < Ca < Mg < P < K. Annual stand net productivity was strongly correlated to N + K loss from litter bags (r = 0.96).

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