scholarly journals Honeybee colonies compensate for pesticide-induced effects on royal jelly composition and brood survival with increased brood production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Schott ◽  
Maximilian Sandmann ◽  
James E. Cresswell ◽  
Matthias A. Becher ◽  
Gerrit Eichner ◽  
...  
Keyword(s):  
Royal Jelly ◽  
Brood Production ◽  
Initiation Rate ◽  
Term Survival ◽  
Individual Level ◽  
Sublethal Doses ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Colony Level

AbstractSublethal doses of pesticides affect individual honeybees, but colony-level effects are less well understood and it is unclear how the two levels integrate. We studied the effect of the neonicotinoid pesticide clothianidin at field realistic concentrations on small colonies. We found that exposure to clothianidin affected worker jelly production of individual workers and created a strong dose-dependent increase in mortality of individual larvae, but strikingly the population size of capped brood remained stable. Thus, hives exhibited short-term resilience. Using a demographic matrix model, we found that the basis of resilience in dosed colonies was a substantive increase in brood initiation rate to compensate for increased brood mortality. However, computer simulation of full size colonies revealed that the increase in brood initiation led to severe reductions in colony reproduction (swarming) and long-term survival. This experiment reveals social regulatory mechanisms on colony-level that enable honeybees to partly compensate for effects on individual level.

Evaluation of the Laxative activity of Saponin Enriched Hydroethanolic Pericarp extract of Sapindus emarginatus in Animal models

2020 ◽  
Vol 16 ◽  
Author(s):  
Lalitha Vivekanandan ◽  
Roxanne Gekonge Mandere ◽  
Sivakumar Thangavel
Keyword(s):  
Animal Models ◽  
Gravimetric Analysis ◽  
Triterpene Saponins ◽  
Laxative Effect ◽  
Saponin Content ◽  
The Family ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Efficacious Drug

Background: Constipation is a common, predominant, chronic gastrointestinal functional disorder. The drugs available to treat constipation are limited because of their side effects in long term use. So we need of efficacious drug to treat constipation. Sapindus emarginatus Vahl belongs to the family Sapindaceae, commonly known as soapnut. Traditionally used for the antipruritic, antifertility, constipation, and anti-inflammatory agents. Objective: The present study was undertaken to evaluate the laxative activity of hydroethanolic pericarp extract of Sapindus emarginatus (HESE) in animal models. Methods: The saponin content in extract was measured by gravimetric analysis. The laxative activity of hydroethanolic pericarp extract of Sapindus emarginatus is evaluated by the weight of feces matter, charcoal meal hyperperistalsis test, and loperamide induced constipation model. Results: The saponin content of the soapnut pericarp was 13.48 % and the extract was found to be 11.92 %. The results obtained from these models showed a significant dose-dependent increase in fecal weight, peristalsis index, and moisture content compared to control animals. Conclusion: The present study concluded that the oral administration of HESE showed a significant laxative activity by using different animal models. The presence of triterpene saponins is responsible for this activity. Further studies are needed to confirm their mechanism behind the laxative effect. The administration of extract was found to be a valid candidate in constipation therapy.

scholarly journals Melamine disrupts spatial reversal learning and learning strategy via inhibiting hippocampal BDNF-mediated neural activity

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245326
Author(s):  
Wei Sun ◽  
Yuanhua Wu ◽  
Dongxin Tang ◽  
Xiaoliang Li ◽  
Lei An
Keyword(s):  
Cognitive Flexibility ◽  
Reversal Learning ◽  
Neural Activity ◽  
Learning Strategy ◽  
Learning Deficits ◽  
Place Strategy ◽  
Dependent Learning ◽  
Dose Dependent Increase ◽  
Dose Dependent

Although several studies showed adverse neurotoxic effects of melamine on hippocampus (HPC)-dependent learning and reversal learning, the evidence for this mechanism is still unknown. We recently demonstrated that intra-hippocampal melamine injection affected the induction of long-term depression, which is associated with novelty acquisition and memory consolidation. Here, we infused melamine into the HPC of rats, and employed behavioral tests, immunoblotting, immunocytochemistry and electrophysiological methods to sought evidence for its effects on cognitive flexibility. Rats with intra-hippocampal infusion of melamine displayed dose-dependent increase in trials to the criterion in reversal learning, with no locomotion or motivation defect. Compared with controls, melamine-treated rats avoided HPC-dependent place strategy. Meanwhile, the learning-induced BDNF level in the HPC neurons was significantly reduced. Importantly, bilateral intra-hippocampal BDNF infusion could effectively mitigate the suppressive effects of melamine on neural correlate with reversal performance, and rescue the strategy bias and reversal learning deficits. Our findings provide first evidence for the effect of melamine on cognitive flexibility and suggest that the reversal learning deficit is due to the inability to use place strategy. Furthermore, the suppressive effects of melamine on BDNF-mediated neural activity could be the mechanism, thus advancing the understanding of compulsive behavior in melamine-induced and other neuropsychiatric disorders.

scholarly journals Resource acquisition and allocation traits in symbiotic rhizobia with implications for life-history outside of legume hosts

2018 ◽  
Vol 5 (12) ◽  
pp. 181124 ◽  
Author(s):  
Katherine E. Muller ◽  
R. Ford Denison
Keyword(s):  
Root Nodules ◽  
Natural Populations ◽  
Heritable Variation ◽  
Free Living ◽  
Term Survival ◽  
Individual Level ◽  
Dividing Cells ◽  
Term Functions ◽  
Microbial Symbionts

Resources that microbial symbionts obtain from hosts may enhance fitness during free-living stages when resources are comparatively scarce. For rhizobia in legume root nodules, diverting resources from nitrogen fixation to polyhydroxybutyrate (PHB) has been discussed as a source of host–symbiont conflict. Yet, little is known about natural variation in PHB storage and its implications for rhizobial evolution. We therefore measured phenotypic variation in natural rhizobia populations and investigated how PHB might contribute to fitness in the free-living stage. We found that natural populations of rhizobia from Glycine max and Chamaecrista fasciculata had substantial, heritable variation in PHB acquisition during symbiosis. A model simulating temperature-dependent metabolic activity showed that the observed range of stored PHB per cell could support survival for a few days, for active cells, or over a century for sufficiently dormant cells. Experiments with field-isolated Bradyrhizobium in starvation culture suggest PHB is partitioned asymmetrically in dividing cells, consistent with individual-level bet-hedging previously demonstrated in E. meliloti . High-PHB isolates used more PHB over the first month, yet still retained more PHB for potential long-term survival in a dormant state. These results suggest that stored resources like PHB may support both short-term and long-term functions that contribute to fitness in the free-living stage.

scholarly journals No dose-dependent increase in fracture risk after long-term exposure to high doses of retinol or beta-carotene

2012 ◽  
Vol 24 (4) ◽  
pp. 1285-1293 ◽  
Author(s):  
G. L. Ambrosini ◽  
A. P. Bremner ◽  
A. Reid ◽  
D. Mackerras ◽  
H. Alfonso ◽  
...  
Keyword(s):  
Fracture Risk ◽  
Beta Carotene ◽  
High Doses ◽  
Dose Dependent Increase ◽  
Dose Dependent

scholarly journals Antiglycation Effects of Carnosine and Other Compounds on the Long-Term Survival of Escherichia coli

2010 ◽  
Vol 76 (24) ◽  
pp. 7925-7930 ◽  
Author(s):  
Evan D. Pepper ◽  
Michael J. Farrell ◽  
Gary Nord ◽  
Steven E. Finkel
Keyword(s):  
Escherichia Coli ◽  
Culture Medium ◽  
Term Survival ◽  
Long Term Survival ◽  
E Coli ◽  
Human Disorders ◽  
Domains Of Life ◽  
Carboxymethyl Lysine ◽  
Dose Dependent

ABSTRACT Glycation, or nonenzymatic glycosylation, is a chemical reaction between reactive carbonyl-containing compounds and biomolecules containing free amino groups. Carbonyl-containing compounds include reducing sugars such as glucose or fructose, carbohydrate-derived compounds such as methylglyoxal and glyoxal, and nonsugars such as polyunsaturated fatty acids. The latter group includes molecules such as proteins, DNA, and amino lipids. Glycation-induced damage to these biomolecules has been shown to be a contributing factor in human disorders such as Alzheimer's disease, atherosclerosis, and cataracts and in diabetic complications. Glycation also affects Escherichia coli under standard laboratory conditions, leading to a decline in bacterial population density and long-term survival. Here we have shown that as E. coli aged in batch culture, the amount of carboxymethyl lysine, an advanced glycation end product, accumulated over time and that this accumulation was affected by the addition of glucose to the culture medium. The addition of excess glucose or methylglyoxal to the culture medium resulted in a dose-dependent loss of cell viability. We have also demonstrated that glyoxylase enzyme GloA plays a role in cell survival during glycation stress. In addition, we have provided evidence that carnosine, folic acid, and aminoguanidine inhibit glycation in prokaryotes. These agents may also prove to be beneficial to eukaryotes since the chemical processes of glycation are similar in these two domains of life.

scholarly journals Extrapolating Survival from Randomized Trials Using External Data: A Review of Methods

2016 ◽  
Vol 37 (4) ◽  
pp. 377-390 ◽  
Author(s):  
Christopher Jackson ◽  
John Stevens ◽  
Shijie Ren ◽  
Nick Latimer ◽  
Laura Bojke ◽  
...  
Keyword(s):  
Survival Data ◽  
Randomized Trials ◽  
Research Priorities ◽  
Future Research ◽  
Term Survival ◽  
Individual Level ◽  
External Data ◽  
The United Kingdom ◽  
Term Data

This article describes methods used to estimate parameters governing long-term survival, or times to other events, for health economic models. Specifically, the focus is on methods that combine shorter-term individual-level survival data from randomized trials with longer-term external data, thus using the longer-term data to aid extrapolation of the short-term data. This requires assumptions about how trends in survival for each treatment arm will continue after the follow-up period of the trial. Furthermore, using external data requires assumptions about how survival differs between the populations represented by the trial and external data. Study reports from a national health technology assessment program in the United Kingdom were searched, and the findings were combined with “pearl-growing” searches of the academic literature. We categorized the methods that have been used according to the assumptions they made about how the hazards of death vary between the external and internal data and through time, and we discuss the appropriateness of the assumptions in different circumstances. Modeling choices, parameter estimation, and characterization of uncertainty are discussed, and some suggestions for future research priorities in this area are given.

Donor treatment with pegylated G-CSF augments the generation of IL-10-producing regulatory T cells and promotes transplantation tolerance

Blood ◽  
2004 ◽  
Vol 103 (9) ◽  
pp. 3573-3581 ◽  
Author(s):  
Edward S. Morris ◽  
Kelli P. A. MacDonald ◽  
Vanessa Rowe ◽  
Diana H. Johnson ◽  
Tatjana Banovic ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Interleukin 10 ◽  
Term Survival ◽  
Donor T Cells ◽  
Dose Dependent Fashion ◽  
Dose Dependent ◽  
Donor Pretreatment

Abstract We investigated whether the protection from graft-versus-host disease (GVHD) afforded by donor treatment with granulocyte colony-stimulating factor (G-CSF) could be enhanced by dose escalation. Donor treatment with human G-CSF prevented GVHD in the B6 → B6D2F1 murine model in a dose-dependent fashion, and murine G-CSF provided equivalent protection from GVHD at 10-fold lower doses. Donor pretreatment with a single dose of pegylated G-CSF (peg-G-CSF) prevented GVHD to a significantly greater extent than standard G-CSF (survival, 75% versus 11%, P < .001). Donor T cells from peg-G-CSF-treated donors failed to proliferate to alloantigen and inhibited the responses of control T cells in an interleukin 10 (IL-10)-dependent fashion in vitro. T cells from peg-G-CSF-treated IL-10-/- donors induced lethal GVHD; T cells from peg-G-CSF-treated wild-type (wt) donors promoted long-term survival. Whereas T cells from peg-G-CSF wt donors were able to regulate GVHD induced by T cells from control-treated donors, T cells from G-CSF-treated wt donors and peg-G-CSF-treated IL-10-/- donors did not prevent mortality. Thus, peg-G-CSF is markedly superior to standard G-CSF for the prevention of GVHD following allogeneic stem cell transplantation (SCT), due to the generation of IL-10-producing regulatory T cells. These data support prospective clinical trials of peg-G-CSF-mobilized allogeneic blood SCT. (Blood. 2004;103:3573-3581)

scholarly journals Alteration of thyroid hormone secretion after long-term exposure to low doses of endocrine disruptor DDT

2014 ◽  
Vol 60 (6) ◽  
pp. 655-660 ◽  
Author(s):  
N.V. Yaglova ◽  
V.V. Yaglov
Keyword(s):  
Thyroid Hormone ◽  
Hormone Secretion ◽  
Thyroid Peroxidase ◽  
Low Doses ◽  
Male Wistar Rats ◽  
Total Thyroxine ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Exogenous Substances

Endocrine disruptors are exogenous substances that exhibit hormone-like action and consequently disrupt homeostatic action of endogenous hormones. DDT is the most common disruptor. The objective was to evaluate changes in thyroid hormone secretion after long-term exposure to low doses of DDT. The experiment was performed on male Wistar rats. The rats were given DDT at doses of 1.89±0.86 мg/kg/day and 7.77±0.17 мg/kg/day for 6 and 10 weeks. Dose dependent increase of serum total thyroxine, total triiodthyronine, and thyroid peroxidase was revealed after 6 weeks exposure. After 10 weeks free thyroxine secretion was reduced. Such alterations of the thyroid status are typical for iodine deficient goiter. The data obtained indicate that the main mechanism of DDT action includes disruption of thyroxine secretion by thyrocytes, but not inhibition of deiodinase activity and decrease of blood thyroid binding proteins.

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