scholarly journals GUY1 confers complete female lethality and is a strong candidate for a male-determining factor in Anopheles stephensi

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Frank Criscione ◽  
Yumin Qi ◽  
Zhijian Tu
Keyword(s):  
Y Chromosome ◽  
Disease Transmission ◽  
Anopheles Stephensi ◽  
Urban Malaria ◽  
Endogenous Gene ◽  
Primary Signal ◽  
Strong Candidate ◽  
Transgenic Manipulation ◽  
First Time ◽  
Determining Factor

Despite their importance in sexual differentiation and reproduction, Y chromosome genes are rarely described because they reside in repeat-rich regions that are difficult to study. Here, we show that Guy1, a unique Y chromosome gene of a major urban malaria mosquito Anopheles stephensi, confers 100% female lethality when placed on the autosomes. We show that the small GUY1 protein (56 amino acids in length) causes female lethality and that males carrying the transgene are reproductively more competitive than their non-transgenic siblings under laboratory conditions. The GUY1 protein is a primary signal from the Y chromosome that affects embryonic development in a sex-specific manner. Our results have demonstrated, for the first time in mosquitoes, the feasibility of stable transgenic manipulation of sex ratios using an endogenous gene from the male-determining chromosome. These results provide insights into the elusive M factor and suggest exciting opportunities to reduce mosquito populations and disease transmission.

scholarly journals Guy1, a Y-linked embryonic signal, regulates dosage compensation in Anopheles stephensi by increasing X gene expression

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yumin Qi ◽  
Yang Wu ◽  
Randy Saunders ◽  
Xiao-Guang Chen ◽  
Chunhong Mao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dosage Compensation ◽  
Anopheles Stephensi ◽  
Wild Type ◽  
Significant Difference ◽  
Primary Signal ◽  
X Gene ◽  
Strong Candidate ◽  
Female Specific ◽  
Determining Factor

We previously showed that Guy1, a primary signal expressed from the Y chromosome, is a strong candidate for a male-determining factor that confers female-specific lethality in Anopheles stephensi (Criscione et al., 2016). Here, we present evidence that Guy1 increases X gene expression in Guy1-transgenic females from two independent lines, providing a mechanism underlying the Guy1-conferred female lethality. The median level gene expression (MGE) of X-linked genes is significantly higher than autosomal genes in Guy1-transgenic females while there is no significant difference in MGE between X and autosomal genes in wild-type females. Furthermore, Guy1 significantly upregulates at least 40% of the 996 genes across the X chromosome in transgenic females. Guy1-conferred female-specific lethality is remarkably stable and completely penetrant. These findings indicate that Guy1 regulates dosage compensation in An. stephensi and components of dosage compensation may be explored to develop novel strategies to control mosquito-borne diseases.

scholarly journals Mosquito species and age influence thermal performance of traits relevant to malaria transmission

2019 ◽  
Author(s):  
KL Miazgowicz ◽  
EA Mordecai ◽  
SJ Ryan ◽  
RJ Hall ◽  
J Owen ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Egg Production ◽  
Life History Traits ◽  
Anopheles Stephensi ◽  
Mosquito Species ◽  
Urban Malaria ◽  
Temperature Dependent ◽  
Biting Rate ◽  
Transmission Models ◽  
Target Intervention

AbstractModels predicting disease transmission are a vital tool in the control of mosquito populations and malaria reduction as they can target intervention efforts. We compared the performance of temperature-dependent transmission models when mosquito life history traits were allowed to change across the lifespan of Anopheles stephensi, the urban malaria mosquito, to models parameterized with commonly derived estimates of lifetime trait values. We conducted an experiment on adult female An. stephensi to generate daily per capita values for lifespan, egg production, and biting rate at six constant temperatures. Both temperature and age significantly affected trait values. Further, we found quantitative and qualitative differences between temperature-trait relationships estimated based on daily rates versus directly observed lifetime values. Incorporating these temperature-trait relationships into an expression governing transmission suitability, relative R0(T), model resulted in minor differences in the breadth of suitable temperatures for Plasmodium falciparum transmission between the two models constructed from only An. stephensi trait data, but a substantial increase in breadth compared to a previously published model consisting of trait data from multiple mosquito species. Overall this work highlights the importance of considering how mosquito trait values vary with mosquito age and mosquito species when generating temperature-based environmental suitability predictions of transmission.

scholarly journals Efficient TALEN-mediated gene knockin at the bovine Y chromosome and generation of a sex-reversal bovine

2021 ◽  
Author(s):  
Ming Wang ◽  
ZhaoLin Sun ◽  
Fangrong Ding ◽  
Haiping Wang ◽  
Ling Li ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Nuclear Transfer ◽  
Sex Reversal ◽  
Practical Application ◽  
Transcription Activator ◽  
New Methods ◽  
Fetal Fibroblasts ◽  
Male Phenotype ◽  
Solid Foundation ◽  
First Time

AbstractFunctional elucidation of bovine Y-chromosome genes requires available genome editing technologies. Meanwhile, it has yet to be proven whether the bovine Sry gene is the main or single factor involved in the development of the male phenotype in bovine. Here, we efficiently knocked out four Y-linked genes (Sry, ZFY, DDX3Y, and EIF2S3Y) in bovine fetal fibroblasts (BFFs) with transcription activator-like effector nucleases (TALENs) individually. Furthermore, we used TALEN-mediated gene knockin at the Sry gene and generated a sex-reversal bovine by somatic cell nuclear transfer (SCNT). The resulting bovine had only one ovary and was sterile. We demonstrate, for the first time, that the Sry gene is an important sex-determining gene in bovine. Our method lays a solid foundation for detecting the biology of the bovine Y chromosome, as it may provide an alternative biological model system for the study of mammalian sex determination, and new methods for the practical application in agricultural, especially for sex predetermination.

scholarly journals Exchange Speed of Four-Component Nanorotors Correlates with Hammett Substituent Constants

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 116-125
Author(s):  
Yi-Fan Li ◽  
Amit Ghosh ◽  
Pronay Kumar Biswas ◽  
Suchismita Saha ◽  
Michael Schmittel
Keyword(s):  
Linear Correlation ◽  
Bond Cleavage ◽  
Head Group ◽  
Ligand Interaction ◽  
Exchange Frequency ◽  
Rate Determining Step ◽  
Head Groups ◽  
Substituent Constants ◽  
First Time ◽  
Determining Factor

Three distinct four-component supramolecular nanorotors were prepared, using, for the first time, bipyridine instead of phenanthroline stations in the stator. Following our established self-sorting protocol to multicomponent nanodevices, the nanorotors were self-assembled by mixing the stator, rotators with various pyridine head groups, copper(I) ions and 1,4-diazabicyclo[2.2.2]octane (DABCO). Whereas the exchange of a phenanthroline vs. a bipyridine station did not entail significant changes in the rotational exchange frequency, the para-substituents at the pyridine head group of the rotator had drastic consequences on the speed: 4-OMe (k298 = 35 kHz), 4-H (k298 = 77 kHz) and 4-NO2 (k298 = 843 kHz). The exchange frequency (log k) showed an excellent linear correlation with both the Hammett substituent constants and log K of the copper(I)–ligand interaction, proving that rotator–copper(I) bond cleavage is the key determining factor in the rate-determining step.

scholarly journals Host density predicts the probability of parasitism by avian brood parasites

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180204 ◽  
Author(s):  
Iliana Medina ◽  
Naomi E. Langmore
Keyword(s):  
Spatial Distribution ◽  
Reproductive Success ◽  
Host Species ◽  
Field Data ◽  
Host Density ◽  
Brood Parasites ◽  
Parasitism Rates ◽  
Analyse Data ◽  
First Time ◽  
Determining Factor

The spatial distribution of hosts can be a determining factor in the reproductive success of parasites. Highly aggregated hosts may offer more opportunities for reproduction but can have better defences than isolated hosts. Here we connect macro- and micro-evolutionary processes to understand the link between host density and parasitism, using avian brood parasites as a model system. We analyse data across more than 200 host species using phylogenetic comparative analyses and quantify parasitism rate and host reproductive success in relation to spatial distribution using field data collected on one host species over 6 years. Our comparative analysis reveals that hosts occurring at intermediate densities are more likely to be parasitized than colonial or widely dispersed hosts. Correspondingly, our intraspecific field data show that individuals living at moderate densities experience higher parasitism rates than individuals at either low or high densities. Moreover, we show for the first time that the effect of host density on host reproductive success varies according to the intensity of parasitism; hosts have greater reproductive success when living at high densities if parasitism rates are high, but fare better at low densities when parasitism rates are low. We provide the first evidence of the trade-off between host density and parasitism at both macro- and micro-evolutionary scales in brood parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

scholarly journals Reduced susceptibility to selected synthetic pyrethroids in urban malaria vector Anopheles stephensi: a case study in Mangalore city, South India

2010 ◽  
Vol 9 (1) ◽  
pp. 179 ◽  
Author(s):  
Satyanarayan Tiwari ◽  
Susanta K Ghosh ◽  
Vijay P Ojha ◽  
Aditya P Dash ◽  
Kamaraju Raghavendra
Keyword(s):  
Malaria Vector ◽  
South India ◽  
Anopheles Stephensi ◽  
Synthetic Pyrethroids ◽  
Urban Malaria

Does the roof type of a house influence the presence of adult Anopheles stephensi, urban malaria vector? – evidence from a few slum settings in Chennai, India

2021 ◽  
Author(s):  
Sangamithra Ravishankaran ◽  
Aswin Asokan ◽  
N. A. Johnson Amala Justin ◽  
Shalu Thomas ◽  
Vasna Joshua ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Anopheles Stephensi ◽  
Urban Malaria

scholarly journals Intestinal spirochetosis: first cases reported in Brazil and the use of immunohistochemistry as an aid in histopathological diagnosis

1996 ◽  
Vol 38 (1) ◽  
pp. 45-53 ◽  
Author(s):  
T. de Brito ◽  
Marina P. Sandoval ◽  
Ana G. Silva ◽  
R. C. Saad ◽  
W. Colaiacovo
Keyword(s):  
Disease Transmission ◽  
Treponema Pallidum ◽  
Surface Epithelium ◽  
Histopathological Diagnosis ◽  
Intestinal Spirochetosis ◽  
A Cell ◽  
Colon And Rectum ◽  
First Time ◽  
Brachyspira Aalborgi ◽  
Routine Stains

Colonization of the colon and rectum by intestinal spirochetes is detected for the first time in Brazil in 4 of 282 (1.41%) patients who had undergone sigmoidoscopy and/or colonoscopy with a histopathological diagnosis of chronic non specific-colitis. This frequency is probably understimated, since surgically obtained specimens were not considered in the present study. Histopathological diagnosis was performed using routine stains like hematoxylin-eosin which showed the typical, of 3-µm thick hematoxyphilic fringe on the brush border of the surface epithelium, and by silver stains like the Warthin-Starry stain. Immunohistochemical procedures using two, polyclonal, primary antibodies, one against Treponema pallidum and the other against Leptospira interrogans serovar copenhageni serogroup Icterohaemorrhagiae cross-reacted with spirochetal antigen/s producing a marked contrast of the fringe over the colonic epithelium, preserving the spiral-shaped morphology of the parasite. In one case with marked diarrhea, immunohistochemistry detected spirochetal antigen/s within a cell in an intestinal crypt, thus demonstrating that the infection can be more widely disseminated than suspected using routine stains. Immunohistochemical procedures, thus, greatly facilitate the histological diagnosis of intestinal spirochetosis and may contribute to a better understanding of the pathogenesis of the disease. Transmission and scanning electron microscopy performed in one case showed that the spirochete closely resembled the species designated as Brachyspira aalborgi.

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