scholarly journals Interactions of Oxygen at High Pressure and Radiation in Drosophila

1966 ◽  
Vol 49 (3) ◽  
pp. 537-549 ◽  
Author(s):  
J.J. Thomas ◽  
R.C. Baxter ◽  
W.O. Fenn

Oxygen at high pressure (OHP) and X-irradiation can interact in the fruit fly Drosophila melanogaster to potentiate toxic actions characteristic of one agent alone. 1000 kvp X-irradiation in doses of 30, 60, and 75 kr accelerated the acute immobilization of young male Drosophila by oxygen at 7.8 atm, up to rates twice that observed with such oxygen pressure alone. X-irradiation alone in these dosages did not acutely immobilize the Drosophila. X-irradiation during exposure to 7.8 atm pO2 was more effective and consistent in producing this potentiation than was X-irradiation that preceded exposure to OHP. Acute OHP toxicity in young female Drosophila was not potentiated by 75 kr of X-irradiation. On the other hand, shortening of the life span of young male Drosophila by the above doses of X-irradiation was augmented significantly by a concurrent 40 min exposure to OHP (which alone did not significantly decrease life span). This shows, for the first time, that oxygen can affect not only the acute effects of radiation, but also the residual irreversible effects indicated by the life span shortening.

2009 ◽  
Vol 29 (4) ◽  
pp. 792-802 ◽  
Author(s):  
Fudong Liu ◽  
Rongwen Yuan ◽  
Sharon E Benashski ◽  
Louise D McCullough

Acute ischemic stroke is a leading cause of mortality and disability in the elderly. Age is the most important nonmodifiable risk factor for stroke, yet many preclinical models continue to examine only young male animals. It remains unclear how experimental stroke outcomes change with aging and with biologic sex. If sex differences are present, it is not known whether these reflect an intrinsic differing sensitivity to stroke or are secondary to the loss of estrogen with aging. We subjected both young and aging mice of both sexes to middle cerebral artery occlusion (MCAO). Young female mice had smaller strokes compared with age-matched males, an effect that was reversed by ovariectomy. Stroke damage increased with aging in female mice, whereas male mice had decreased damage after MCAO. Blood–brain barrier (BBB) permeability changes are correlated with infarct size. However, aging mice had significantly less edema formation, an effect that was independent of sex and histologic damage. Differences in the cellular response to stroke occur across the life span in both male and female mice. These differences need to be considered when developing relevant therapies for stroke patients, the majority of whom are elderly.


2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 789
Author(s):  
Athanasios Dalakouras ◽  
Ioannis Ganopoulos

Exogenous application of RNA molecules is a potent method to trigger RNA interference (RNAi) in plants in a transgene-free manner. So far, all exogenous RNAi (exo-RNAi) applications have aimed to trigger mRNA degradation of a given target. However, the issue of concomitant epigenetic changes was never addressed. Here, we report for the first time that high-pressure spraying of dsRNAs can trigger de novo methylation of promoter sequences in plants.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 308
Author(s):  
Paloma Della Giustina ◽  
Thiago Mastrangelo ◽  
Sohel Ahmad ◽  
Gabriel Mascarin ◽  
Carlos Caceres

A common strategy used to maintain sterile fly quality without sacrificing sterility is to irradiate the insects under an oxygen-reduced atmosphere. So far, sterilizing doses for the South American fruit fly Anastrepha fraterculus have only been determined under normoxia. Our study reports for the first time the dose-sterility response under hypoxia for two different A. fraterculus strains. The pupae were derived from a bisexual strain (a Brazilian-1 population) and a recently developed genetic sexing strain (GSS-89). Two hours prior to irradiation, pupae were transferred to sealed glass bottles and irradiated when oxygen concentration was below 3%. Four types of crosses with nonirradiated flies of the bisexual strain were set to assess sterility for each radiation dose. For males from both strains, Weibull dose–response curves between radiation doses and the proportion of egg hatch, egg-to-pupa recovery, and recovery of adults were determined. The GSS males revealed high sterility/mortality levels compared to males from the bisexual strain at doses < 40 Gy, but a dose of 74 Gy reduced egg hatch by 99% regardless of the male strain and was considered the sterilizing dose. The fertility of irradiated females was severely affected even at low doses under hypoxia.


Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 441-452
Author(s):  
Dominika M Wloch ◽  
Krzysztof Szafraniec ◽  
Rhona H Borts ◽  
Ryszard Korona

Abstract Estimates of the rate and frequency distribution of deleterious effects were obtained for the first time by direct scoring and characterization of individual mutations. This was achieved by applying tetrad analysis to a large number of yeast clones. The genomic rate of spontaneous mutation deleterious to a basic fitness-related trait, that of growth rate, was U = 1.1 × 10−3 per diploid cell division. Extrapolated to the fruit fly and humans, the per generation rate would be 0.074 and 0.92, respectively. This is likely to be an underestimate because single mutations with selection coefficients s &lt; 0.01 could not be detected. The distribution of s ≥ 0.01 was studied both for spontaneous and induced mutations. The latter were induced by ethyl methanesulfonate (EMS) or resulted from defective mismatch repair. Lethal changes accounted for ~30–40% of the scored mutations. The mean s of nonlethal mutations was fairly high, but most frequently its value was between 0.01 and 0.05. Although the rate and distribution of very small effects could not be determined, the joint share of such mutations in decreasing average fitness was probably no larger than ~1%.


2008 ◽  
Vol 74 (24) ◽  
pp. 7821-7823 ◽  
Author(s):  
Kai Linke ◽  
Nagarajan Periasamy ◽  
Matthias Ehrmann ◽  
Roland Winter ◽  
Rudi F. Vogel

ABSTRACT High hydrostatic pressure (HHP) is suggested to influence the structure and function of membranes and/or integrated proteins. We demonstrate for the first time HHP-induced dimer dissociation of membrane proteins in vivo with Vibrio cholerae ToxR variants in Escherichia coli reporter strains carrying ctx::lacZ fusions. Dimerization ceased at 20 to 50 MPa depending on the nature of the transmembrane segments rather than on changes in the ToxR lipid bilayer environment.


2003 ◽  
Vol 2 (5-6) ◽  
pp. 270-278 ◽  
Author(s):  
Stephen L Helfand ◽  
Sharon K Inouye
Keyword(s):  

2014 ◽  
Vol 716-717 ◽  
pp. 363-369
Author(s):  
Zhen Hua Xie ◽  
Dong Yang ◽  
Sha Sha Liang ◽  
Zhi Yun Jia

The technology of hierarchical multiple high-pressure grouting is an effective approach to manage high and steep slope of broken rock mass. The number of grouting is one of the key parameters of this technology. By the analysis of mechanics and grouting theory, the anchoring effect mainly is affected by anchor slurry vein and the contact area with rock mass. Based on the system analysis of slurry vein development for first time and many times high-pressure grouting, the process flow for hierarchical multiple high-pressure grouting is put forward. Serve the rock permeability changes before and after grouting as an indicator measuring slurry and rock surface area, the method of determining grouting number based on the reliable probability is got. Combined with the engineering example of Shouyun Iron Mine, this paper puts forward the reliability criteria of working state of hierarchical multiple high-pressure grouting. Through the probability calculation, the best number of grouting is 4 times. The tests of permeability of rock mass and drawing force verify the accuracy of this determination method.


BMJ ◽  
1996 ◽  
Vol 313 (7062) ◽  
pp. 944-944 ◽  
Author(s):  
G. Falck ◽  
G. Brattebo

Nativa ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 513
Author(s):  
Michele Emily Souza da Silva ◽  
Michel Ariquenes Wochner ◽  
Maria do Socorro Miranda de Sousa ◽  
Marliton Rocha Barreto ◽  
Ricardo Adaime da Silva

As moscas-das-frutas estão presentes em todas as regiões do Brasil e são responsáveis por grandes perdas econômicas em pomares comerciais. Este trabalho teve o objetivo de determinar a riqueza de espécies de moscas-das-frutas, suas respectivas plantas hospedeiras e seus parasitoides em municípios da região norte de Mato Grosso. Foram realizadas coletas de frutos de 34 espécies vegetais, de julho de 2016 a novembro de 2017. Os frutos coletados foram acondicionados em recipientes plásticos para observar a emergência das moscas-das-frutas e parasitoides. Foram obtidos 2.709 espécimes de moscas-das-frutas (cinco espécies) e 179 espécimes de parasitoides (três espécies). Este trabalho apresenta os primeiros registros de hospedeiros de moscas-das-frutas para o Mato Grosso. Adicionalmente, os parasitoides Utetes anastrephae Viereck e Asobara anastrephae (Muesebeck) são relatados pela primeira vez no Estado.Palavras-chave: Anastrepha; Ceratitis capitata; Relação tritrófica; Amazônia Meridional. FRUIT FLIES, THEIR HOST PLANTS AND PARASITOIDS IN THE NORTHERN STATE OF MATO GROSSO, BRAZIL ABSTRACT: Fruit flies are present in all regions of Brazil and are responsible for large economic losses in commercial orchards. This work aimed to determine the richness of fruit fly species, their host plants and their parasitoids in municipalities in the northern region of Mato Grosso. We collected fruits from 34 plant species, from July 2016 to November 2017. The collected fruits were packed in plastic containers to observe the emergence of fruit flies and parasitoids. We obtained 2,709 specimens of fruit flies (five species) and 179 specimens of parasitoids (three species). This work presents the first records of hosts of fruit flies for Mato Grosso. In addition, the parasitoids Utetes anastrephae Viereck and Asobara anastrephae (Muesebeck) are reported for the first time in the State.Keywords: Anastrepha; Ceratitis capitata; Tritrophic relationship; Southern Amazon.


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