In vitro studies on the environmental biology of Goiodes colchici (Denny) (Mallophaga : Ischnocera) I. The effects of temperature and humidity on the bionomics of G. colchici

1970 ◽  
Vol 18 (4) ◽  
pp. 379 ◽  
Author(s):  
RT Williams
Keyword(s):  
Egg Production ◽  
Egg Laying ◽  
Adult Longevity ◽  
Environmental Biology ◽  
Chill Coma ◽  
Temperature And Humidity ◽  
Effects Of Temperature ◽  
High Level ◽  
Body Lice

Pheasant body lice, G. colchici, were exposed to various conditions of temperature and humidity, and the consequent variations in adult longevity, egg production, fecundity, and egg resorption recorded. Temperatures in the 30-40C range were found to be essential for normal existence. Above this, animals died within 48 hr. Below this, irrespective of humidity, chill-coma supervened, survival was curtailed, and no eggs were laid. At 30�C, survival was maximal, but few eggs were laid. Due to a high level of fecundity, egg production was maximal at 35C at a high humidity, and survival equalled that at 30C. Levels of fecundity, egg-laying, and survival dropped as the humidity fell, and also as the temperature increased or decreased about 35C. It is evident that survival, fecundity, egg production, and egg-laying are closely geared to temperature and humidity.

In vitro studies on the environmental biology of Goiodes colchici (Denny) (Mallophaga : Ischnocera) II. The effects of temperature and humidity on water loss

1970 ◽  
Vol 18 (4) ◽  
pp. 391 ◽  
Author(s):  
RT Williams
Keyword(s):  
Water Loss ◽  
Similar Rate ◽  
Weight Changes ◽  
Environmental Biology ◽  
Efficient Control ◽  
Temperature And Humidity ◽  
Survival And Reproduction ◽  
Effects Of Temperature ◽  
Body Lice

Weight changes have been used to assess the effect of various conditions of temperature and humidity on the rates of water loss of pheasant body lice, G. colchici. Both living and dead animals, in 0% R.H., lose water at a low but increasing rate from 32 to 40C; above this temperature, the rate of water loss suddenly increases. Living insects lose water at half the rate of dead ones over this temperature range. At 35C and 0% R.H., all non-moulting stages lose water at a similar rate. Moulting insects lose water at half the rate of non-moulting ones. The threshold humidity for survival of these insects is within the range 52.5-62.5% R.H. The weight of mature animals does not vary at different humidities above the threshold. In general, the patterns of humidity requirements and regulation of water loss of G. colchici do not differ from those of other insects. There is no evidence that the dependence of these animals on temperatures in the 30-40C range for survival and reproduction is connected with more efficient control of water loss under these conditions.

The influence of nutrition on egg-production and longevity in unmated female body-lice (Pediculus humanus corporis: Anoplura)

Parasitology ◽  
1941 ◽  
Vol 33 (1) ◽  
pp. 40-46 ◽  
Author(s):  
A. J. Haddow
Keyword(s):  
Female Body ◽  
Egg Production ◽  
Egg Laying ◽  
The Body ◽  
Unmated Female ◽  
Pediculus Humanus ◽  
The Third ◽  
Significant Difference ◽  
The Mean ◽  
Body Lice

1. Isolated unmated female body-lice were worn in pillboxes between the skin and the clothes. They were kept constantly on the body but, by a simple device, groups of ten were permitted feeding periods of different length. These groups were fed for 4, 8, 12, 16, 20 and 24 hr. per day respectively. Another group of ten were never allowed to feed after the last moult.2. Some of the figures for egg yield were high. Lice in the 24 hr. group were able to maintain a rate of ten eggs per day for 4−5 days at a time.3. No significant difference in longevity or rate of egg-laying was found to exist between the 12, 16, 20 and 24 hr. groups nor between the 4 and 8 hr. groups but a pronounced and significant difference exists between the 8 and 12 hr. groups. Below 12 hr. there is a sharp fall in longevity and rate of egg production. The unfed group all died, without laying, on the third day.4. The rate of laying as shown by the mode increases progressively with increase in time allowed daily for feeding.5. With regard to the mean eggs per louse the position is less clear. It is felt that the 24 hr. group may differ significantly from the 12, 16 and 20 hr. groups but this is uncertain.

INFLUENCE OF TEMPERATURE AND HUMIDITY ON LONGEVITY, FECUNDITY, AND RATE OF INCREASE OF THE MITE TYROPHAGUS PUTRESCENTIAE (SCHRANK) (ACARINA: ACARIDAE) REARED ON MOLD CULTURES

1961 ◽  
Vol 39 (6) ◽  
pp. 869-876 ◽  
Author(s):  
I. Rivard
Keyword(s):  
Egg Production ◽  
Food Products ◽  
Egg Laying ◽  
Oviposition Period ◽  
Tyrophagus Putrescentiae ◽  
Influence Of Temperature ◽  
Adult Females ◽  
Rate Of Increase ◽  
Temperature And Humidity

Adult females of Tyrophagus putrescentiae (Schrank), a mite that infests stored food products, were reared individually on mold cultures at all combinations of five temperatures and four humidities. A definite diminution in life usually occurred with increase in either temperature or humidity, and the oviposition period was the most affected. Total egg-production and rate of laying were highest at 72.5° F and 90% R.H., and both generally decreased with an increase in temperature or decrease in humidity from these values. Peak of egg-laying, however, was reached sooner at higher temperatures but egg-production was maintained at relatively high levels for shorter periods. Rate of increase was greatest and approximately the same at 90% R.H. within the range 72.5° to 81.5° F.

scholarly journals Elevated temperatures diminish the effects of a highly resistant rice variety on the brown planthopper

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Finbarr G. Horgan ◽  
Arriza Arida ◽  
Goli Ardestani ◽  
Maria Liberty P. Almazan
Keyword(s):  
Egg Production ◽  
Elevated Temperatures ◽  
Rice Variety ◽  
Brown Planthopper ◽  
Susceptible Variety ◽  
Egg Laying ◽  
Adult Survival ◽  
Resistant Variety ◽  
Adult Longevity ◽  
Rice Varieties

AbstractThis study compares the effects of temperature (constant at 15, 20, 25, 30 and 35 °C) on adult longevity, oviposition, and nymph development of the brown planthopper, Nilaparvata lugens, on susceptible and resistant rice varieties. The resistant variety contained the BPH32 gene. In our experiments, nymphs failed to develop to adults at 15, 20 and 35 °C on either variety. Host resistance had its greatest effect in reducing adult survival at 20–25 °C and its greatest effect in reducing nymph weight gain at 25 °C. This corresponded with optimal temperatures for adult survival (20–25 °C) and nymph development (25–30 °C). At 25 and 30 °C, adult females achieved up to three oviposition cycles on the susceptible variety, but only one cycle on the resistant variety. Maximum egg-laying occurred at 30 °C due to larger numbers of egg batches produced during the first oviposition cycle on both the susceptible and resistant varieties, and larger batches during the second and third oviposition cycles on the susceptible variety; however, resistance had its greatest effect in reducing fecundity at 25 °C. This revealed a mismatch between the optimal temperatures for resistance and for egg production in immigrating females. Increasing global temperatures could reduce the effectiveness of anti-herbivore resistance in rice and other crops where such mismatches occur.

scholarly journals Pharmacological inhibition of lysine-specific demethylase 1 (LSD1) induces global transcriptional deregulation and ultrastructural alterations that impair viability in Schistosoma mansoni

2019 ◽  
Author(s):  
Vitor Coutinho Carneiro ◽  
Isabel Caetano de Abreu da Silva ◽  
Murilo Sena Amaral ◽  
Adriana S.A. Pereira ◽  
Gilbert O. Silveira ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schistosoma Mansoni ◽  
Drug Target ◽  
Egg Production ◽  
Egg Laying ◽  
New Drugs ◽  
Biological Processes ◽  
Lysine Specific Demethylase

AbstractTreatment and control of schistosomiasis still rely on only one effective drug, praziquantel (PZQ), and due to mass treatment, the increasing risk of selecting for schistosome strains that are resistant to PZQ has alerted investigators to the urgent need to develop novel therapeutic strategies. The histone-modifying enzymes (HMEs) represent promising targets for the development of epigenetic drugs against Schistosoma mansoni. In the present study, we targeted the S. mansoni lysine-specific demethylase 1 (SmLSD1), a transcriptional corepressor, using a novel and selective synthetic inhibitor, MC3935. We synthesized a novel and potent LSD1 inhibitor, MC3935, which was used to treat schistosomula or adult worms in vitro. By using cell viability assays and optical and electron microscopy, we showed that treatment with MC3935 affected parasite motility, egg-laying, tegument, and cellular organelle structures, culminating in the death of schistosomula and adult worms. In silico molecular modeling and docking analysis suggested that MC3935 binds to the catalytic pocket of SmLSD1. Western blot analysis revealed that MC3935 inhibited SmLSD1 demethylation activity of H3K4me1/2. Knockdown of SmLSD1 by RNAi recapitulated MC3935 phenotypes in adult worms. RNA-seq analysis of MC3935-treated parasites revealed significant differences in gene expression related to critical biological processes. Collectively, our findings show that SmLSD1 is a promising drug target for the treatment of schistosomiasis and strongly support the further development and in vivo testing of selective schistosome LSD1 inhibitors.Author SummarySchistosomiasis mansoni is a chronic and debilitating tropical disease caused by the helminth Schistosoma mansoni. The control and treatment of the disease rely almost exclusively on praziquantel (PZQ). Thus, there is an urgent need to search for promising protein targets to develop new drugs. Drugs that inhibit enzymes that modify the chromatin structure have been developed for a number of diseases. We and others have shown that S. mansoni epigenetic enzymes are also potential therapeutic targets. Here we evaluated the potential of the S. mansoni histone demethylase LSD1 (SmLSD1) as a drug target. We reported the synthesis of a novel and potent LSD1 inhibitor, MC3935, and show that it selectively inhibited the enzymatic activity of SmLSD1. Treatment of juvenile or adult worms with MC3935 caused severe damage to the tegument of the parasites and compromised egg production. Importantly, MC3935 proved to be highly toxic to S. mansoni, culminating in the death of juvenile or adult worms within 96 h. Transcriptomic analysis of MC3935-treated parasites revealed changes in the gene expression of hundreds of genes involved in key biological processes. Importantly, SmLSD1 contains unique sequences within its polypeptide chain that could be explored to develop a S. mansoni selective drug.

scholarly journals The Fimbrial Protein FlfA from Gallibacterium anatis Is a Virulence Factor and Vaccine Candidate

2013 ◽  
Vol 81 (6) ◽  
pp. 1964-1973 ◽  
Author(s):  
Ragnhild J. Bager ◽  
Barbara Nesta ◽  
Susanne E. Pors ◽  
Marco Soriani ◽  
Laura Serino ◽  
...  
Keyword(s):  
Egg Production ◽  
Vaccine Candidate ◽  
Gene Clusters ◽  
Egg Laying ◽  
Vaccine Antigen ◽  
Immunogold Electron Microscopy ◽  
Content Type ◽  
Subunit Protein ◽  
Fimbrial Subunit

ABSTRACTThe Gram-negative bacteriumGallibacterium anatisis a major cause of salpingitis and peritonitis in egg-laying chickens, leading to decreased egg production worldwide. Widespread multidrug resistance largely prevents treatment of this organism using traditional antimicrobial agents, while antigenic diversity hampers disease prevention by classical vaccines. Thus, insight into its pathogenesis and knowledge about important virulence factors is urgently required. A key event during the colonization and invasion of mucosal surfaces is adherence, and recently, at least three F17-like fimbrial gene clusters were identified in the genomes of severalG. anatisstrains. The objective of this study was to characterize the putative F17-like fimbrial subunit protein FlfA fromG. anatis12656-12 and determine its importance for virulence.In vitroexpression and surface exposure of FlfA was demonstrated by flow cytometry and immunofluorescence microscopy. The predicted function of FlfA as a fimbrial subunit protein was confirmed by immunogold electron microscopy. AnflfAdeletion mutant (ΔflfA) was generated inG. anatis12656-12, and importantly, this mutant was significantly attenuated in the natural chicken host. Furthermore, protection againstG. anatis12656-12 could be induced by immunizing chickens with recombinant FlfA. Finally,in vitroexpression of FlfA homologs was observed in a genetically diverse set ofG. anatisstrains, suggesting the potential of FlfA as a serotype-independent vaccine candidate This is the first study describing a fimbrial subunit protein ofG. anatiswith a clear potential as a vaccine antigen.

Effects of temperature and humidity on the development of eggs ofToxocara canisunder laboratory conditions

2005 ◽  
Vol 79 (4) ◽  
pp. 327-331 ◽  
Author(s):  
M.I. Gamboa
Keyword(s):  
Elevated Temperatures ◽  
Toxocara Canis ◽  
Soil Samples ◽  
Egg Maturation ◽  
Three Samples ◽  
Temperature And Humidity ◽  
Survival And Development ◽  
Effects Of Temperature ◽  
Increasing Temperature

AbstractThe influence of temperature and humidity on the survival and development ofToxocara caniseggs in anin vitromodel system was investigated. Two soil samples were inoculated withT. caniseggs and maintained at 3% and 50% humidity and temperatures of 19–24°C. Nine soil samples were inoculated withT. caniseggs of which three samples were kept at 4°C with humidities at 3%, 15%, and 30%; three were maintained at 21°C and three more were incubated at 34°C, and at the same three humidity levels. Samples were monitored every 7 days for a total of 2 months, for the presence and development of eggs. With increasing temperature, the number of eggs undergoing development increased (P<0.01); the number of deformed eggs decreased, the number of infective eggs increased (P<0.01), and egg maturation was accelerated. A decrease in the survival of infective eggs occurred at 34°C. An increase in humidity produced a rise in the number of developed eggs at all three temperatures (P<0.01). This study suggests that elevated temperatures accelerated the development as well as the degradation of eggs ofT. canis, whereas the range in humidity was directly correlated with egg development.

The metalloprotease inhibitor 1,10-phenanthroline affects Schistosoma mansoni motor activity, egg laying and viability

Parasitology ◽  
1998 ◽  
Vol 116 (4) ◽  
pp. 319-325 ◽  
Author(s):  
T. A. DAY ◽  
G.-Z. CHEN
Keyword(s):  
Motor Activity ◽  
Adult Worm ◽  
Egg Production ◽  
Egg Laying ◽  
Muscle Fibres ◽  
Significant Protection ◽  
Extracellular Medium ◽  
Metalloprotease Inhibitor ◽  
Dose Dependent

The Zn2+-chelating metalloprotease inhibitor 1,10-phenanthroline (phenanthroline, 5–150 μM) elicited dose-dependent contraction of the longitudinal and circular (transverse) musculature of adult male schistosomes. At the same concentrations, phenanthroline did not cause contraction of dispersed individual muscle fibres. The phenanthroline-induced contractions were reduced by the inclusion of 100 or 300 μM Zn2+ in the extracellular medium. Phenanthroline (0·5–150 μM) also inhibited the egg production of adult worm pairs in vitro, with a 98% reduction at 50 μM. When worm pairs were exposed to phenanthroline, the males detached from the dish and released the females, resulting in unpaired worms. At the higher concentrations (50 and 150 μM), the worms were killed in vitro. Worm burdens were reduced by over 50% in infected mice injected with phenanthroline (20 mg/kg/day for 4 days), but twice the dose resulted in only a 25% reduction. Phenanthroline injections also induced an hepatic shift and an unpairing of adult worms in infected mice, and the female worms appeared degenerate and lacked gut pigmentation. Mice fed a diet containing 0·3% phenanthroline received significant protection from infection when challenged with schistosome cercaria, where phenanthroline-fed mice had 94% fewer adult worms than control mice. The broad range of phenanthroline effects on schistosomes suggests broad and important functions for metalloproteases in these worms.

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

2019 ◽  
Author(s):  
Daria Monaldi ◽  
Dante Rotili ◽  
Julien Lancelot ◽  
Martin Marek ◽  
Nathalie Wössner ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Human Cancer ◽  
Egg Laying ◽  
Human Cancer Cells ◽  
Parasite Survival ◽  
Survival And Reproduction ◽  
Emergence Of Resistance ◽  
First Time ◽  
Parasitic Life Cycle

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

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