scholarly journals Bumble bee (Bombus impatiens) survival, pollen usage, and reproduction are not affected by oxalate oxidase at realistic concentrations in American chestnut (Castanea dentata) pollen

2021 ◽  
Author(s):  
Andrew E. Newhouse ◽  
Anastasia E. Allwine ◽  
Allison D. Oakes ◽  
Dakota F. Matthews ◽  
Scott H. McArt ◽  
...  
Keyword(s):  
Transgene Expression ◽  
Fold Increase ◽  
Oxalate Oxidase ◽  
Bumble Bees ◽  
Bombus Impatiens ◽  
American Chestnut ◽  
Wheat Gene ◽  
Substantial Risk ◽  
Construction Activity ◽  
High Concentrations

AbstractTransgenic American chestnut trees expressing a wheat gene for oxalate oxidase (OxO) can tolerate chestnut blight, but as with any new restoration material, they should be carefully evaluated before being released into the environment. Native pollinators such as bumble bees are of particular interest: Bombus impatiens use pollen for both a source of nutrition and a hive building material. Bees are regular visitors to American chestnut flowers and likely contribute to their pollination, so depending on transgene expression in chestnut pollen, they could be exposed to this novel source of OxO during potential restoration efforts. To evaluate the potential risk to bees from OxO exposure, queenless microcolonies of bumble bees were supplied with American chestnut pollen containing one of two concentrations of OxO, or a no-OxO control. Bees in microcolonies exposed to a conservatively estimated field-realistic concentration of OxO in pollen performed similarly to no-OxO controls; there were no significant differences in survival, bee size, pollen use, hive construction activity, or reproduction. A ten-fold increase in OxO concentration resulted in noticeable but non-significant decreases in some measures of pollen usage and reproduction compared to the no-OxO control. These effects are similar to what is often seen when naturally produced secondary metabolites are supplied to bees at unrealistically high concentrations. Along with the presence of OxO in many other environmental sources, these data collectively suggest that oxalate oxidase at field-realistic concentrations in American chestnut pollen is unlikely to present substantial risk to bumble bees.

scholarly journals THE RATE OF BACTERICIDAL ACTION OF PENICILLIN IN VITRO AS A FUNCTION OF ITS CONCENTRATION, AND ITS PARADOXICALLY REDUCED ACTIVITY AT HIGH CONCENTRATIONS AGAINST CERTAIN ORGANISMS

1948 ◽  
Vol 88 (1) ◽  
pp. 99-131 ◽  
Author(s):  
Harry Eagle ◽  
A. D. Musselman
Keyword(s):  
Bacterial Species ◽  
Fold Increase ◽  
Bactericidal Effect ◽  
Penicillin G ◽  
Bacterial Suspension ◽  
Maximal Effect ◽  
Maximal Rate ◽  
Effective Level ◽  
High Concentrations

1. The concentrations of penicillin G which (a) reduced the net rate of multiplication, (b) exerted a net bactericidal effect, and (c) killed the organisms at a maximal rate, have been defined for a total of 41 strains of α- and ß-hemolytic streptococci, Staphylococcus aureus and Staphylococcus albus, Diplococcus pneumoniae, and the Reiter treponoma. 2. The concentration which killed the organisms at a maximal rate was 2 to 20 times the minimal effective level ("sensitivity" as ordinarily defined). With some organisms, even a 32,000-fold increase beyond this maximally effective level did not further increase the rate of its bactericidal effect. However, with approximately half the strains here studied (all 4 strains of group B ß-hemolytic streptococci, 4 of 5 group C strains, 5 of 7 strains of Streptococcus fecalis, 2 of 4 other α-hemolytic streptococci, and 4 of 9 strains of staphylococci), when the concentration of penicillin was increased beyond that optimal level, the rate at which the organisms died was paradoxically reduced rather than increased, so that the maximal effect was obtained only within a relatively narrow optimal zone. 3. There were marked differences between bacterial species, and occasionally between different strains of the same species, not only with respect to the effective concentrations of penicillin, but also with respect to the maximal rate at which they could be killed by the drug in any concentration. Although there was a rough correlation between these two factors, there were many exceptions; individual strains affected only by high concentrations of penicillin might nevertheless be killed rapidly, while strains sensitive to minute concentrations might be killed only slowly. 4. Within the same bacterial suspension, individual organisms varied only to a minor degree with respect to the effective concentrations of penicillin. They varied strikingly, however, in their resistance to penicillin as measured by the times required to kill varying proportions of the cells.

scholarly journals Thunderstorm outflows preceding epidemics of asthma during spring and summer

Thorax ◽  
2001 ◽  
Vol 56 (6) ◽  
pp. 468-471
Author(s):  
G B Marks ◽  
J R Colquhoun ◽  
S T Girgis ◽  
M Hjelmroos Koski ◽  
A B A Treloar ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Ground Level ◽  
Fold Increase ◽  
Underlying Mechanism ◽  
Detailed Examination ◽  
Asthma Exacerbations ◽  
Eastern Australia ◽  
The Difference ◽  
High Concentrations ◽  
Thunderstorm Outflow

BACKGROUNDA study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism.METHODSA case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations.RESULTSThunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4–12 fold increase in the ambient concentration of grass pollen grains.CONCLUSIONSThese findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.

scholarly journals The effect of copper excess on iron metabolism in sheep

1978 ◽  
Vol 170 (1) ◽  
pp. 137-143 ◽  
Author(s):  
E C Theil ◽  
K T Calvert
Keyword(s):  
Iron Metabolism ◽  
Iron Concentration ◽  
Transferrin Saturation ◽  
Fold Increase ◽  
Copper Treatment ◽  
Excess Copper ◽  
High Concentrations ◽  
Copper Excess ◽  
Effect Of Copper ◽  
Haemoglobin Content

Sheep were treated with large amounts of copper (20 mg of CuSO4,5H2O/kg body wt. per day) for 9 weeks to examine the effect of copper excess on iron metabolism. In addition to confirming that massive haemolysis and accumulation of copper occurs in the liver, kidney and plasma after 7 weeks of exposure to excess copper, it was observed that excess copper produced an increased plasma iron concentration and transferrin saturation within 1 week. Further, iron preferentially accumulated in the spleen between 4 and 6 weeks of copper treatment, producing 3-fold increases in the iron content of both the ferritin and non-ferritin fractions. A 3-4 fold increase was also observed in the amount of ferritin that could be isolated from the spleen. The copper treatment had little or no effect on the concentration of iron in the liver and bone marrow. The following properties of erythrocytes were also unaffected by copper treatment: size, haemoglobin content and pyruvate kinase activity, although the erythrocyte concentration of copper increased after 6 weeks. Copper accumulated in the spleen between 6 and 9 weeks, probably owing to the phagocytosis of erythrocytes containing high concentrations of copper. The data suggest that copper excess influences iron metabolism, initially by causing a compensated haemolytic anaemia, and later by interfering with re-utilization of iron from ferritin in the reticuloendothelial cells of the spleen.

Mirror Image Pattern Matching By Bumble Bees

Behaviour ◽  
1995 ◽  
Vol 132 (1-2) ◽  
pp. 87-93 ◽  
Author(s):  
C.M.S. Plowright ◽  
Y.G. Korneluk
Keyword(s):  
Pattern Matching ◽  
Honey Bees ◽  
Mirror Image ◽  
Bumble Bees ◽  
Bombus Impatiens ◽  
Artificial Flower ◽  
Choice Tests ◽  
Image Transformations ◽  
Image Pattern

AbstractBumble bees (Bombus impatiens) were trained to discriminate between a rewarding and non-rewarding artificial flower that differed only in their configuration of four identical petals. On choice tests between 2 empty flowers, the bees chose the flower with the configuration of the rewarding flower over the mirror image, but the mirror image over a novel flower. This behaviour is the same as has been observed with honey bees and functional interpretations are considered. The problem of distinguishing between left-right pattern reversals and true mirror image transformations is discussed.

Abstract TP94: Mesenchymal Stromal Cells Behave Differently When Exposed to Medications Commonly Prescribed to Stroke Patients

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Nikunj Satani ◽  
Bing Yang ◽  
Duyen M Nghiem ◽  
Xiaopei Xi ◽  
Adrian P Gee ◽  
...  
Keyword(s):  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
High Glucose ◽  
Fold Increase ◽  
Stroke Recovery ◽  
Stroke Patients ◽  
Healthy Humans ◽  
Tnf Α ◽  
High Concentrations ◽  
And Function

Background: As a promising investigational therapy for stroke recovery, mesenchymal stromal cells (MSCs) are in various stages of clinical trials. MSCs may promote recovery through cytokine release and immunomodulation. Stroke patients typically are treated with antiplatelets and medications for hypertension and hyperlipidemia. We explored the effect of commonly prescribed drugs at physiological concentrations on MSCs. Methods: Clinical grade bone marrow MSCs from healthy donor at passage 2 were thawed and re-suspended in serum free media. Monocytes (Mo) were isolated from peripheral blood of healthy humans. MSCs and Mo were cultured alone as well as in co-culture and exposed to simvastatin, atenolol, losartan, captopril, or aspirin. They were also exposed to high glucose (upto 40mM) to simulate hyperglycemia. At 24 hours of incubation, media was collected and TNF-α concentration was measured, as an index of immunomodulation of Mo by MSCs. Cell viability was also measured (using MTT assay and flow cytometry). Results: There were significant effects of all drugs on viability of MSCs but with no impact on Mo. More importantly, Losartan (dose independent), Simvastatin and Atenolol (dose-dependent) reduced the viability of MSCs even at the pharmacologically relevant concentrations (Fig 1). High glucose had no effect on viability of MSCs or Mo. TNF-α secretion from co-culture of MSCs and Mo at 24 hours showed differences at very high doses of aspirin (2-fold increase), atenolol (0.5 fold decrease), and glucose (0.5 fold decrease) (data not shown). However, these high concentrations are unlikely to be achieved pharmacologically in plasma of patients treated with these drugs. Conclusion: Exposure of MSCs to clinically relevant drugs can alter their viability and function. Our results suggest that stroke trials involving use of intravenous MSCs should consider the differential impact of commonly prescribed medications on MSCs function.

scholarly journals The Cigarette Smoke Carcinogen Benzo[a]pyrene Enhances Human Papillomavirus Synthesis

2007 ◽  
Vol 82 (2) ◽  
pp. 1053-1058 ◽  
Author(s):  
Samina Alam ◽  
Michael J. Conway ◽  
Horng-Shen Chen ◽  
Craig Meyers
Keyword(s):  
Human Papillomavirus ◽  
Cigarette Smoke ◽  
Cancer Progression ◽  
Fold Increase ◽  
Epidemiological Studies ◽  
Low Concentrations ◽  
Virion Morphogenesis ◽  
High Concentrations ◽  
Cervical Cells ◽  
Viral Titers

ABSTRACT Epidemiological studies suggest that cigarette smoke carcinogens are cofactors which synergize with human papillomavirus (HPV) to increase the risk of cervical cancer progression. Benzo[a]pyrene (BaP), a major carcinogen in cigarette smoke, is detected in the cervical mucus and may interact with HPV. Exposure of cervical cells to high concentrations of BaP resulted in a 10-fold increase in HPV type 31 (HPV31) viral titers, whereas treatment with low concentrations of BaP resulted in an increased number of HPV genome copies but not an increase in virion morphogenesis. BaP exposure also increased HPV16 and HPV18 viral titers. Overall, BaP modulation of the HPV life cycle could potentially enhance viral persistence, host tissue carcinogenesis, and permissiveness for cancer progression.

Identification of a blood-derived chemoattractant for neutrophils and lymphocytes as a novel CC chemokine, Regakine-1

Blood ◽  
2001 ◽  
Vol 97 (8) ◽  
pp. 2197-2204 ◽  
Author(s):  
Sofie Struyf ◽  
Paul Proost ◽  
Jean-Pierre Lenaerts ◽  
Griet Stoops ◽  
Anja Wuyts ◽  
...  
Keyword(s):  
Acute Infection ◽  
Large Family ◽  
Fold Increase ◽  
Cell Types ◽  
Platelet Factor ◽  
Cc Chemokine ◽  
Chemotactic Protein ◽  
Biologic Effects ◽  
Cc Chemokines ◽  
High Concentrations

Abstract Chemokines constitute a large family of chemotactic cytokines that selectively attract different blood cell types. Although most inflammatory chemoattractants are only induced and released in the circulation during acute infection, a restricted number of CXC and CC chemokines are constitutively present in normal plasma at high concentrations. Here, such a chemotactic protein was purified to homogeneity from serum and fully identified as a novel CC chemokine by mass spectrometry and amino acid sequence analysis. The protein, tentatively designated Regakine-1, shows less than 50% sequence identity with any known chemokine. This novel CC chemokine chemoattracts both neutrophils and lymphocytes but not monocytes or eosinophils. Its modest chemotactic potency but high blood concentration is similar to that of other chemokines present in the circulation, such as hemofiltrate CC chemokine-1, platelet factor-4, and β-thromboglobulin. Regakine-1 did not induce neutrophil chemokinesis. However, it synergized with the CXC chemokines interleukin-8 and granulocyte chemotactic protein-2, and the CC chemokine monocyte chemotactic protein-3, resulting in an at least a 2-fold increase of the neutrophil and lymphocyte chemotactic response, respectively. The biologic effects of homogeneous natural Regakine-1 were confirmed with chemically synthesized chemokine. Like other plasma chemokines, it is expected that Regakine-1 plays a unique role in the circulation during normal or pathologic conditions.

Lethal and sub-lethal effects of spinosad on bumble bees (Bombus impatiens Cresson)

2005 ◽  
Vol 61 (7) ◽  
pp. 619-626 ◽  
Author(s):  
Lora A Morandin ◽  
Mark L Winston ◽  
Michelle T Franklin ◽  
Virginia A Abbott
Keyword(s):  
Bumble Bees ◽  
Bombus Impatiens ◽  
Lethal Effects
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