30 results on '"Michalkova, Veronika"'
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2. Epoxidation of juvenile hormone was a key innovation improving insect reproductive fitness
- Author
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Nouzova, Marcela, Edwards, Marten J., Michalkova, Veronika, Ramirez, Cesar E., Ruiz, Marnie, Areiza, Maria, DeGennaro, Matthew, Fernandez-Lima, Francisco, Feyereisen, René, Jindra, Marek, and Noriega, Fernando G.
- Published
- 2021
3. Author Correction: Following de novo triglyceride dynamics in ovaries of Aedes aegypti during the previtellogenic stage
- Author
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Tose, Lilian Valadares, Weisbrod, Chad R., Michalkova, Veronika, Nouzova, Marcela, Noriega, Fernando G., and Fernandez‑Lima, Francisco
- Published
- 2021
- Full Text
- View/download PDF
4. Following de novo triglyceride dynamics in ovaries of Aedes aegypti during the previtellogenic stage
- Author
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Tose, Lilian Valadares, Weisbrod, Chad R., Michalkova, Veronika, Nouzova, Marcela, Noriega, Fernando G., and Fernandez-Lima, Francisco
- Published
- 2021
- Full Text
- View/download PDF
5. Comparative genomic analysis of six Glossina genomes, vectors of African trypanosomes
- Author
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Attardo, Geoffrey M., Abd-Alla, Adly M. M., Acosta-Serrano, Alvaro, Allen, James E., Bateta, Rosemary, Benoit, Joshua B., Bourtzis, Kostas, Caers, Jelle, Caljon, Guy, Christensen, Mikkel B., Farrow, David W., Friedrich, Markus, Hua-Van, Aurélie, Jennings, Emily C., Larkin, Denis M., Lawson, Daniel, Lehane, Michael J., Lenis, Vasileios P., Lowy-Gallego, Ernesto, Macharia, Rosaline W., Malacrida, Anna R., Marco, Heather G., Masiga, Daniel, Maslen, Gareth L., Matetovici, Irina, Meisel, Richard P., Meki, Irene, Michalkova, Veronika, Miller, Wolfgang J., Minx, Patrick, Mireji, Paul O., Ometto, Lino, Parker, Andrew G., Rio, Rita, Rose, Clair, Rosendale, Andrew J., Rota-Stabelli, Omar, Savini, Grazia, Schoofs, Liliane, Scolari, Francesca, Swain, Martin T., Takáč, Peter, Tomlinson, Chad, Tsiamis, George, Van Den Abbeele, Jan, Vigneron, Aurelien, Wang, Jingwen, Warren, Wesley C., Waterhouse, Robert M., Weirauch, Matthew T., Weiss, Brian L., Wilson, Richard K., Zhao, Xin, and Aksoy, Serap
- Published
- 2019
- Full Text
- View/download PDF
6. Juvenile hormone controls ovarian development in female Anopheles albimanus mosquitoes
- Author
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Hernández-Martínez, Salvador, Cardoso-Jaime, Víctor, Nouzova, Marcela, Michalkova, Veronika, Ramirez, Cesar E., Fernandez-Lima, Francisco, and Noriega, Fernando G.
- Published
- 2019
- Full Text
- View/download PDF
7. Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans)
- Author
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Engl, Tobias, Michalkova, Veronika, Weiss, Brian L., Uzel, Güler D., Takac, Peter, Miller, Wolfgang J., Abd-Alla, Adly M. M., Aksoy, Serap, and Kaltenpoth, Martin
- Published
- 2018
- Full Text
- View/download PDF
8. Coupling stable isotope labelling and LC-TIMS-TOF MS/MS for de novo mosquito ovarian lipid studies
- Author
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Tose, Lilian V., Ramirez, Cesar E., Michalkova, Veronika, Nouzova, Marcela, Noriega, Fernando G., and Fernandez-Lima, Francisco
- Subjects
Diglycerides ,Culicidae ,Tandem Mass Spectrometry ,Isotope Labeling ,Ion Mobility Spectrometry ,Animals ,Reproducibility of Results ,Female ,Article ,Chromatography, Liquid - Abstract
There is a need to better understand the lipid metabolisms during the mosquito ovarian development. Lipids are the major source of energy supporting ovarian follicles development in mosquitoes. In this paper, we describe the complementary use of stable isotope labelling (SIL) and high-resolution mass spectrometry-based tools for the investigation of de novo triglycerides (TG) and diglycerides (DG) during the ovarian previtellogenic (PVG) stage (4 - 6 days post-eclosion) of female adult Aedes aegypti. Liquid chromatography coupled to high resolution trapped ion mobility spectrometry – parallel accumulation sequential fragmentation - mass spectrometry (LC-TIMS-PASEF TOF MS/MS) allowed the separation and quantification of non-labeled and (2)H/(13)C-labelled TG and DG species. Three SIL strategies were evaluated (H(2)O/(2)H(2)O with 50:50 and 95:5 mixtures, (13)C-sucrose, and (13)C-glucose). Results showed wide applicability with no signs of lipid ovarian impairment by SIL induced toxicity. The analytical workflow based on LC-TIMS-TOF MS/MS provided high confidence and high reproducibility for lipid DG and TG identification and SIL incorporation based on their separation by RT, CCS, and accurate m/z. In addition, the SIL fatty acid chain incorporation was evaluated using PASEF MS/MS. The (2)H/(13)C incorporation into the mosquito diet provided information on how TG lipids are consumed, stored, and recycled during the PVG stage of ovarian development.
- Published
- 2022
9. Warm Blood Meal Increases Digestion Rate and Milk Protein Production to Maximize Reproductive Output for the Tsetse Fly, Glossina morsitans.
- Author
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Benoit, Joshua B., Lahondère, Chloé, Attardo, Geoffrey M., Michalkova, Veronika, Oyen, Kennan, Xiao, Yanyu, and Aksoy, Serap
- Subjects
TSETSE-flies ,MILK proteins ,MILK yield ,INSECT physiology ,DIGESTION ,BODY temperature regulation ,BODY temperature - Abstract
Keywords: tsetse; digestion; thermal stress; reproduction EN tsetse digestion thermal stress reproduction 997 11 11/17/22 20221101 NES 221101 1. Molecular characterization of tsetse milk revealed 12 major milk gland proteins, including Transferrin [[7]], a Lipocalin (Milk Gland Protein 1, MGP1 [[7], [9]], nine tsetse-specific milk proteins (MGP2-10; [[7], [10]]), and Acid Sphingomyelinase 1 (aSMase1; [[12]]). [Extracted from the article]
- Published
- 2022
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10. Larval Morphology and Anatomyof the Parasitoid Exorista Larvarum (Diptera: Tachinidae), with an Emphasis on Cephalopharyngeal Skeleton and Digestive Tract
- Author
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Michalková, Veronika, Valigurová, Andrea, Dindo, Maria Luisa, and Vaňhara, Jaromír
- Published
- 2009
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11. Eugregarine trophozoite detachment from the host epithelium via epimerite retraction: Fiction or fact?
- Author
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Valigurová, Andrea, Michalková, Veronika, and Koudela, Břetislav
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- 2009
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12. Coupling Stable Isotope Labeling and Liquid Chromatography-Trapped Ion Mobility Spectrometry-Time-of-Flight-Tandem Mass Spectrometry for De Novo Mosquito Ovarian Lipid Studies.
- Author
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Tose, Lilian V., Ramirez, Cesar E., Michalkova, Veronika, Nouzova, Marcela, Noriega, Fernando G., and Fernandez-Lima, Francisco
- Published
- 2022
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13. Three dimensional secondary ion mass spectrometry imaging (3D-SIMS) of Aedes aegypti ovarian follicles.
- Author
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Castellanos, Anthony, Ramirez, Cesar E., Michalkova, Veronika, Nouzova, Marcela, Noriega, Fernando G., and Fernández-Lima, Francisco
- Subjects
SECONDARY ion mass spectrometry ,AEDES aegypti ,OVARIAN follicle ,FEMALE reproductive organs ,OVUM ,LIPID analysis - Abstract
The mobilization of nutrient reserves into the ovaries of Aedes aegypti mosquitoes after sugar-feeding plays a vital role in the female's reproductive maturation. In the present work, three-dimensional secondary ion mass spectrometry imaging (3D-SIMS) was used to generate ultrahigh spatial resolution (∼1 μm) chemical maps and study the composition and spatial distribution of lipids at the single ovarian follicle level (∼100 μm in size). 3D-Mass Spectrometry Imaging (3D-MSI) allowed the identification of cellular types in the follicle (oocyte, nurse and follicular cells) using endogenous markers, and revealed that most of the triacyglycerides (TGs) were compartmentalized in the oocyte region. By comparing follicles from water-fed and sugar-fed females (n = 2), 3D-MSI-Time of Flight-SIMS showed that TGs were more abundant in ovarian follicles of sugar-fed females; despite relative sample reproducibility per feeding condition, more biological replicates will better support the trends observed. While the current 3D-MSI-TOF-SIMS does not permit MS/MS analysis of the lipid species, complementary LC-MS/MS analysis of the ovarian follicles aided tentative lipid assignments of the SIMS data. The combination of these MS approaches is giving us a first glimpse of the distribution of functionally relevant ovarian lipid molecules at the cellular level. These new tools can be used to investigate the roles of different lipids on follicle fitness and overall mosquito reproductive output. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. Genome sequence of the tsetse fly (Glossina morsitans): vector of African trypanosomiasis : International Glossina Genome Initiative
- Author
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Watanabe, Junichi, Hattori, Masahira, Berriman, Matthew, Lehane, Michael, Hall, Neil, Solano, Philippe, Aksoy, Serap, Hide, Winston, Touré, Yeya, Attardo, Geoffrey, Darby, Alistair, Toyoda, Atsushi, Hertz-Fowler, Christiane, Larkin, Denis, Cotton, James, Sanders, Mandy, Swain, Martin, Quail, Michael, Inoue, Noboru, Ravel, Sophie, Taylor, Todd, Srivastava, Tulika, Sharma, Vineet, Warren, Wesley, Wilson, Richard, Suzuki, Yutaka, Lawson, Daniel, Hughes, Daniel, Megy, Karyn, Masiga, Daniel, Mireji, Paul, Hansen, Immo, Van Den Abbeele, Jan, Benoit, Joshua, Bourtzis, Kostas, Obiero, George, Robertson, Hugh, Jones, Jeffery, Zhou, Jing-Jiang, Field, Linda, Friedrich, Markus, Nyanjom, Steven, Telleria, Erich, Caljon, Guy, Ribeiro, José, Acosta-Serrano, Alvaro, Ooi, Cher-Pheng, Rose, Clair, Price, David, Haines, Lee, Christoffels, Alan, Sim, Cheolho, Pham, Daphne, Denlinger, David, Geiser, Dawn, Omedo, Irene, Winzerling, Joy, Peyton, Justin, Marucha, Kevin, Jonas, Mario, Meuti, Megan, Rawlings, Neil, Zhang, Qirui, Macharia, Rosaline, Michalkova, Veronika, Dashti, Zahra, Baumann, Aaron, Gäde, Gerd, Marco, Heather, Caers, Jelle, Schoofs, Liliane, Riehle, Michael, Hu, Wanqi, Tu, Zhijian, Tarone, Aaron, Malacrida, Anna, Kibet, Caleb, Scolari, Francesca, Koekemoer, Jacobus, Willis, Judith, Gomulski, Ludvik, Falchetto, Marco, Scott, Maxwell, Fu, Shuhua, Sze, Sing-Hoi, Luiz, Thiago, Weiss, Brian, Walshe, Deirdre, Wang, Jingwen, Wamalwa, Mark, Mwangi, Sarah, Ramphul, Urvashi, Snyder, Anna, Brelsfoard, Corey, Thomas, Gavin, Tsiamis, George, Arensburger, Peter, Rio, Rita, Macdonald, Sandy, Panji, Sumir, Kruger, Adele, Benkahla, Alia, Balyeidhusa, Apollo, Msangi, Atway, Okoro, Chinyere, Stephens, Dawn, Stanley, Eleanor, Mpondo, Feziwe, Wamwiri, Florence, Mramba, Furaha, Siwo, Geoffrey, Githinji, George, Harkins, Gordon, Murilla, Grace, Lehväslaiho, Heikki, Malele, Imna, Auma, Joanna, Kinyua, Johnson, Ouma, Johnson, Okedi, Loyce, Manga, Lucien, Aslett, Martin, Koffi, Mathurin, Gaunt, Michael, Makgamathe, Mmule, Mulder, Nicola, Manangwa, Oliver, Abila, Patrick, Wincker, Patrick, Gregory, Richard, Bateta, Rosemary, Sakate, Ryuichi, Ommeh, Sheila, Lehane, Stella, Imanishi, Tadashi, Osamor, Victor, and Kawahara, Yoshihiro
- Abstract
Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein-encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology. ispartof: Science vol:344 issue:6182 pages:380-386 ispartof: location:United States status: published
- Published
- 2014
15. JH biosynthesis and hemolymph titers in adult male Aedes aegypti mosquitoes.
- Author
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Nouzova, Marcela, Michalkova, Veronika, Hernández-Martínez, Salvador, Rivera-Perez, Crisalejandra, Ramirez, Cesar E., Fernandez-Lima, Francisco, and Noriega, Fernando G.
- Subjects
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JUVENILE hormones , *BIOSYNTHESIS , *HEMOLYMPH , *AEDES aegypti , *ECDYSIS - Abstract
Juvenile hormone (JH) is a major hormonal regulator in insects. In Aedes aegypti females, JH signals the completion of the ecdysis to the adult stage and initiates reproductive processes. Although the regulation of JH synthesis and titer in Ae. aegypti females has been extensively studied, relatively little is known about changes of JH synthesis and titers in male mosquitoes, as well as on the roles of JH controlling male reproductive biology. A better understanding of male mosquito reproductive biology, including an improved knowledge of the hormonal control of reproduction, could increase the likelihood of success of male-targeting vector control programs. Using a high performance liquid chromatography coupled to electrospray tandem mass spectrometry method, we measured JH biosynthesis and hemolymph levels in male mosquitoes during pupal and adult stages. Our results revealed tightly concomitant changes in JH biosynthesis and JH hemolymph titers. Synthesis of JH III was very low in late pupae, significantly increased during the first 24 h after adult eclosion, and then remained relatively constant during the first six days after adult eclosion. Feeding high sugar diets resulted in an increase of JH synthesis and titers, and starvation significantly decreased JH synthesis, but this effect could be reversed by changing the males back to a high sugar diet. JH synthesis rates were similar in virgin and mated males, but hemolymph JH levels were different in well-nourished virgin and mated males. Starvation resulted in a significant reduction in insemination rates; with well-nourished males inseminating 2 times more females than water-fed. Giving a 20% sugar meal for 24 h to those mosquitoes that were previously starved for 6 days, caused a significant rise in insemination rates, restoring them to levels similar to those recorded for 20% fed males. These results suggest that nutrition plays a role on male fecundity, and this effect might be mediated by JH. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
16. Rapid autophagic regression of the milk gland during involution is critical for maximizing tsetse viviparous reproductive output.
- Author
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Benoit, Joshua B., Michalkova, Veronika, Didion, Elise M., Xiao, Yanyu, Baumann, Aaron A., Attardo, Geoffrey M., and Aksoy, Serap
- Subjects
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TSETSE-flies , *AUTOPHAGY , *TRYPANOSOMIASIS treatment , *MILK proteins , *DROSOPHILA , *REPRODUCTION - Abstract
Tsetse flies are important vectors of human and animal trypanosomiasis. Ability to reduce tsetse populations is an effective means of disease control. Lactation is an essential component of tsetse’s viviparous reproductive physiology and requires a dramatic increase in the expression and synthesis of milk proteins by the milk gland organ in order to nurture larval growth. In between each gonotrophic cycle, tsetse ceases milk production and milk gland tubules undergo a nearly two-fold reduction in width (involution). In this study, we examined the role autophagy plays during tsetse fly milk gland involution and reproductive output. Autophagy genes show elevated expression in tissues associated with lactation, immediately before or within two hours post-parturition, and decline at 24-48h post-parturition. This expression pattern is inversely correlated with that of the milk gland proteins (lactation-specific protein coding genes) and the autophagy inhibitor fk506-bp1. Increased expression of Drosophila inhibitor of apoptosis 1, diap1, was also observed in the milk gland during involution, when it likely prevents apoptosis of milk gland cells. RNAi-mediated knockdown of autophagy related gene 8a (atg8a) prevented rapid milk gland autophagy during involution, prolonging gestation, and reducing fecundity in the subsequent gonotrophic cycle. The resultant inhibition of autophagy reduced the recovery of stored lipids during the dry (non-lactating) periods by 15–20%. Ecdysone application, similar to levels that occur immediately before birth, induced autophagy, and increased milk gland involution even before abortion. This suggests that the ecdysteroid peak immediately preceding parturition likely triggers milk gland autophagy. Population modeling reveals that a delay in involution would yield a negative population growth rate. This study indicates that milk gland autophagy during involution is critical to restore nutrient reserves and allow efficient transition between pregnancy cycles. Targeting post-birth phases of reproduction could be utilized as a novel mechanism to suppress tsetse populations and reduce trypanosomiasis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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17. Adenotrophic Viviparity in Tsetse Flies: Potential for Population Control and as an Insect Model for Lactation.
- Author
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Benoit, Joshua B., Attardo, Geoffrey M., Baumann, Aaron A., Michalkova, Veronika, and Aksoy, Serap
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TSETSE-flies ,VIVIPARITY ,INSECT populations ,INSECTS as carriers of disease ,TRYPANOSOMATIDAE ,REPRODUCTION - Abstract
Tsetse flies ( Glossina spp.), vectors of African trypanosomes, are distinguished by their specialized reproductive biology, defined by adenotrophic viviparity (maternal nourishment of progeny by glandular secretions followed by live birth). This trait has evolved infrequently among insects and requires unique reproductive mechanisms. A key event in Glossina reproduction involves the transition between periods of lactation and nonlactation (dry periods). Increased lipolysis, nutrient transfer to the milk gland, and milk-specific protein production characterize lactation, which terminates at the birth of the progeny and is followed by a period of involution. The dry stage coincides with embryogenesis of the progeny, during which lipid reserves accumulate in preparation for the next round of lactation. The obligate bacterial symbiont Wigglesworthia glossinidia is critical to tsetse reproduction and likely provides B vitamins required for metabolic processes underlying lactation and/or progeny development. Here we describe findings that utilized transcriptomics, physiological assays, and RNA interference-based functional analysis to understand different components of adenotrophic viviparity in tsetse flies. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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18. Vitamin B6 Generated by Obligate Symbionts Is Critical for Maintaining Proline Homeostasis and Fecundity in Tsetse Flies.
- Author
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Michalkova, Veronika, Benoit, Joshua B., Weiss, Brian L., Attardo, Geoffrey M., and Aksoy, Serap
- Subjects
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PROLINE , *HOMEOSTASIS , *INSECT fertility , *TSETSE-flies , *VITAMIN B6 , *RNA interference - Abstract
The viviparous tsetse fly utilizes proline as a hemolymph-borne energy source. In tsetse, biosynthesis of proline from alanine involves the enzyme alanine-glyoxylate aminotransferase (AGAT), which requires pyridoxal phosphate (vitamin B6) as a cofactor. This vitamin can be synthesized by tsetse's obligate symbiont, Wigglesworthia glossinidia. In this study, we examined the role of Wigglesworthia-produced vitamin B6 for maintenance of proline homeostasis, specifically during the energetically expensive lactation period of the tsetse's reproductive cycle. We found that expression of agat, as well as genes involved in vitamin B6 metabolism in both host and symbiont, increases in lactating flies. Removal of symbionts via antibiotic treatment of flies (aposymbiotic) led to hypoprolinemia, reduced levels of vitamin B6 in lactating females, and decreased fecundity. Proline homeostasis and fecundity recovered partially when aposymbiotic tsetse were fed a diet supplemented with either yeast or Wigglesworthia extracts. RNA interference-mediated knockdown of agat in wild-type flies reduced hemolymph proline levels to that of aposymbiotic females. Aposymbiotic flies treated with agat short interfering RNA (siRNA) remained hypoprolinemic even upon dietary supplementation with microbial extracts or B vitamins. Flies infected with parasitic African trypanosomes display lower hemolymph proline levels, suggesting that the reduced fecundity observed in parasitized flies could result from parasite interference with proline homeostasis. This interference could be manifested by competition between tsetse and trypanosomes for vitamins, proline, or other factors involved in their synthesis. Collectively, these results indicate that the presence of Wigglesworthia in tsetse is critical for the maintenance of proline homeostasis through vitamin B6 production. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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- View/download PDF
19. The Homeodomain Protein Ladybird Late Regulates Synthesis of Milk Proteins during Pregnancy in the Tsetse Fly (Glossina morsitans).
- Author
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Attardo, Geoffrey M., Benoit, Joshua B., Michalkova, Veronika, Patrick, Kevin R., Krause, Tyler B., and Aksoy, Serap
- Subjects
MILK proteins ,TSETSE-flies ,HOMEOBOX proteins ,PREGNANCY proteins ,PROTEIN synthesis ,TRANSCRIPTION factors ,GOAT milk - Abstract
Regulation of tissue and development specific gene expression patterns underlies the functional specialization of organs in multi-cellular organisms. In the viviparous tsetse fly (Glossina), the female accessory gland is specialized to generate nutrients in the form of a milk-like secretion to support growth of intrauterine larva. Multiple milk protein genes are expressed specifically in the female accessory gland and are tightly linked with larval development. Disruption of milk protein synthesis deprives developing larvae of nutrients and results in extended larval development and/or in abortion. The ability to cause such a disruption could be utilized as a tsetse control strategy. Here we identify and delineate the regulatory sequence of a major milk protein gene (milk gland protein 1:mgp1) by utilizing a combination of molecular techniques in tsetse, Drosophila transgenics, transcriptomics and in silico sequence analyses. The function of this promoter is conserved between tsetse and Drosophila. In transgenic Drosophila the mgp1 promoter directs reporter gene expression in a tissue and stage specific manner orthologous to that of Glossina. Analysis of the minimal required regulatory region of mgp1, and the regulatory regions of other Glossina milk proteins identified putative homeodomain protein binding sites as the sole common feature. Annotation and expression analysis of Glossina homeodomain proteins identified ladybird late (lbl) as being accessory gland/fat body specific and differentially expressed between lactating/non-lactating flies. Knockdown of lbl in tsetse resulted in a significant reduction in transcript abundance of multiple milk protein genes and in a significant loss of fecundity. The role of Lbl in adult reproductive physiology is previously unknown. These results suggest that Lbl is part of a conserved reproductive regulatory system that could have implications beyond tsetse to other vector insects such as mosquitoes. This system is critical for tsetse fecundity and provides a potential target for development of a reproductive inhibitor. Author Summary: Female tsetse flies (Diptera: Glossina) harbor and give birth to live young. To do this, they nourish their intrauterine larvae with milk secretions. This work focuses upon understanding the regulation of tsetse milk proteins, which are essential for fecundity and are expressed in a temporally and spatially specific manner by pregnant females. We identified the minimal upstream regulatory DNA sequence of the major milk protein gene mgp1, which confers tissue specific expression in the female accessory glands of reproductively active flies. This regulatory sequence functions similarly in transgenic fruit flies (Drosophila melanogaster) and drives expression of reporter gene products in the adult female accessory gland. Comparison of this regulatory sequence with sequences from other characterized milk proteins indicates that conserved homeodomain transcription factors may be responsible for regulating these genes. Analysis of Glossina homeodomain proteins identified an accessory gland/fat body specific factor, Ladybird late (lbl), which appears to regulate the expression of multiple milk proteins. Reduction of lbl levels interferes with milk protein gene expression, which in turn reduces Glossina fecundity. These results suggest that milk proteins in Glossina are regulated by a conserved regulatory system mediated in part by the homeodomain transcription factor lbl. Components of this system could provide a target for development of a tsetse reproductive inhibitor. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
20. Amelioration of Reproduction-Associated Oxidative Stress in a Viviparous Insect Is Critical to Prevent Reproductive Senescence.
- Author
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Michalkova, Veronika, Benoit, Joshua B., Attardo, Geoffrey M., Medlock, Jan, and Aksoy, Serap
- Subjects
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OXIDATIVE stress , *VIVIPARITY , *INSECT reproduction , *CELLULAR aging , *LACTATES , *ANTIOXIDANTS - Abstract
Impact of reproductive processes upon female health has yielded conflicting results; particularly in relation to the role of reproduction-associated stress. We used the viviparous tsetse fly to determine if lactation, birth and involution lead to damage from oxidative stress (OS) that impairs subsequent reproductive cycles. Tsetse females carry an intrauterine larva to full term at each pregnancy cycle, and lactate to nourish them with milk secretions produced by the accessory gland ( = milk gland) organ. Unlike most K-strategists, tsetse females lack an apparent period of reproductive senescence allowing the production of 8–10 progeny over their entire life span. In a lactating female, over 47% of the maternal transcriptome is associated with the generation of milk proteins. The resulting single larval offspring weighs as much as the mother at birth. In studying this process we noted an increase in specific antioxidant enzyme (AOE) transcripts and enzymatic activity at critical times during lactation, birth and involution in the milk gland/fat body organ and the uterus. Suppression of superoxide dismutase (sod) decreased fecundity in subsequent reproductive cycles in young mothers and nearly abolished fecundity in geriatric females. Loss of fecundity was in part due to the inability of the mother to produce adequate milk to support larval growth. Longevity was also impaired after sod knockdown. Generation of OS in virgin females through exogenous treatment with hydrogen peroxide at times corresponding to pregnancy intervals reduced survival, which was exacerbated by sod knockdown. AOE expression may prevent oxidative damage associated with the generation of nutrients by the milk gland, parturition and milk gland breakdown. Our results indicate that prevention of OS is essential for females to meet the growing nutritional demands of juveniles during pregnancy and to repair the damage that occurs at birth. This process is particularly important for females to remain fecund during the latter portion of their lifetime. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
21. The Homeodomain Protein Ladybird Late Regulates Synthesis of Milk Proteins during Pregnancy in the Tsetse Fly (Glossina morsitans).
- Author
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Attardo, Geoffrey M., Benoit, Joshua B., Michalkova, Veronika, Patrick, Kevin R., Krause, Tyler B., and Aksoy, Serap
- Subjects
HOMEOBOX proteins ,MILK proteins ,CHEMICAL synthesis ,PREGNANCY complications ,TSETSE-flies - Abstract
Regulation of tissue and development specific gene expression patterns underlies the functional specialization of organs in multi-cellular organisms. In the viviparous tsetse fly (Glossina), the female accessory gland is specialized to generate nutrients in the form of a milk-like secretion to support growth of intrauterine larva. Multiple milk protein genes are expressed specifically in the female accessory gland and are tightly linked with larval development. Disruption of milk protein synthesis deprives developing larvae of nutrients and results in extended larval development and/or in abortion. The ability to cause such a disruption could be utilized as a tsetse control strategy. Here we identify and delineate the regulatory sequence of a major milk protein gene (milk gland protein 1:mgp1) by utilizing a combination of molecular techniques in tsetse, Drosophila transgenics, transcriptomics and in silico sequence analyses. The function of this promoter is conserved between tsetse and Drosophila. In transgenic Drosophila the mgp1 promoter directs reporter gene expression in a tissue and stage specific manner orthologous to that of Glossina. Analysis of the minimal required regulatory region of mgp1, and the regulatory regions of other Glossina milk proteins identified putative homeodomain protein binding sites as the sole common feature. Annotation and expression analysis of Glossina homeodomain proteins identified ladybird late (lbl) as being accessory gland/fat body specific and differentially expressed between lactating/non-lactating flies. Knockdown of lbl in tsetse resulted in a significant reduction in transcript abundance of multiple milk protein genes and in a significant loss of fecundity. The role of Lbl in adult reproductive physiology is previously unknown. These results suggest that Lbl is part of a conserved reproductive regulatory system that could have implications beyond tsetse to other vector insects such as mosquitoes. This system is critical for tsetse fecundity and provides a potential target for development of a reproductive inhibitor. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
22. A Novel Highly Divergent Protein Family Identified from a Viviparous Insect by RNA-seq Analysis: A Potential Target for Tsetse Fly-Specific Abortifacients.
- Author
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Benoit, Joshua B., Attardo, Geoffrey M., Michalkova, Veronika, Krause, Tyler B., Bohova, Jana, Zhang, Qirui, Baumann, Aaron A., Mireji, Paul O., Takáč, Peter, Denlinger, David L., Ribeiro, Jose M., and Aksoy, Serap
- Subjects
TSETSE-flies ,INSECT larvae ,LACTATION ,MILK proteins ,PROTEIN synthesis ,SPHINGOMYELINASE ,HOMEOSTASIS - Abstract
In tsetse flies, nutrients for intrauterine larval development are synthesized by the modified accessory gland (milk gland) and provided in mother's milk during lactation. Interference with at least two milk proteins has been shown to extend larval development and reduce fecundity. The goal of this study was to perform a comprehensive characterization of tsetse milk proteins using lactation-specific transcriptome/milk proteome analyses and to define functional role(s) for the milk proteins during lactation. Differential analysis of RNA-seq data from lactating and dry (non-lactating) females revealed enrichment of transcripts coding for protein synthesis machinery, lipid metabolism and secretory proteins during lactation. Among the genes induced during lactation were those encoding the previously identified milk proteins (milk gland proteins 1–3, transferrin and acid sphingomyelinase 1) and seven new genes (mgp4–10). The genes encoding mgp2–10 are organized on a 40 kb syntenic block in the tsetse genome, have similar exon-intron arrangements, and share regions of amino acid sequence similarity. Expression of mgp2–10 is female-specific and high during milk secretion. While knockdown of a single mgp failed to reduce fecundity, simultaneous knockdown of multiple variants reduced milk protein levels and lowered fecundity. The genomic localization, gene structure similarities, and functional redundancy of MGP2–10 suggest that they constitute a novel highly divergent protein family. Our data indicates that MGP2–10 function both as the primary amino acid resource for the developing larva and in the maintenance of milk homeostasis, similar to the function of the mammalian casein family of milk proteins. This study underscores the dynamic nature of the lactation cycle and identifies a novel family of lactation-specific proteins, unique to Glossina sp., that are essential to larval development. The specificity of MGP2–10 to tsetse and their critical role during lactation suggests that these proteins may be an excellent target for tsetse-specific population control approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
23. Inhibition of juvenile hormone synthesis in mosquitoes by the methylation inhibitor 3-deazaneplanocin A (DZNep).
- Author
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Nouzova, Marcela, Michalkova, Veronika, Ramirez, Cesar E., Fernandez-Lima, Francisco, and Noriega, Fernando G.
- Subjects
- *
JUVENILE hormones , *HORMONE synthesis , *MOSQUITOES , *AEDES aegypti , *TRYPSIN , *METHYLATION , *ADENOSINES - Abstract
Juvenile hormone (JH), synthesized by the corpora allata (CA), controls development and reproduction in mosquitoes through its action on thousands of JH-responsive genes. These JH-dependent processes can be studied using tools that increase or decrease JH titers in vitro and in vivo. Juvenile hormone acid methyl transferase (JHAMT) is a critical JH biosynthetic enzyme. JHAMT utilizes the methyl donor S-adenosyl-methionine (SAM) to methylate farnesoic acid (FA) into methyl farnesoate (MF), releasing the product S-adenosyl-L-homocysteine (AdoHcy), which inhibits JHAMT. S-adenosyl-homocysteine hydrolase (SAHH) catalyzes AdoHcy hydrolysis to adenosine and homocysteine, alleviating AdoHcy inhibition of JHAMT. 3-deazaneplanocin A (DZNep), an analog of adenosine, is an inhibitor of SAHH, and an epigenetic drug for cancer therapy. We tested the effect of DZNep on in vitro JH synthesis by CA of mosquitoes. DZNep inhibited JH synthesis in a dose-response fashion. Addition of MF, but not of FA relieved the inhibition, demonstrating a direct effect on JHAMT. In vivo experiments, with addition of DZNep to the sugar ingested by mosquitoes, resulted in a dose-response decrease in JH synthesis and JH hemolymphatic titers, as well as expression of early trypsin, a JH-dependent gene. Our studies suggest that DZNep can be employed to lower JH synthesis and titer in experiments evaluating JH-controlled processes in mosquitoes. Image 1 • 3-deazaneplanocin A (DZNep) inhibits in vitro JH synthesis by the corpora-allata of Aedes aegypti mosquitoes in a dose-dependent manner. • Addition of DZNep to the sugar meal results in a decrease in JH synthesis and JH hemolymphatic titer. • DZNep decreases JH synthesis by affecting juvenile hormone acid methyl transferase activity. • Feeding DZNep causes a decrease in the expression of early trypsin, a well-characterized JH target gene. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
24. The Spermatophore in Glossina morsitans morsitans: Insights into Male Contributions to Reproduction.
- Author
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Scolari, Francesca, Benoit, Joshua B., Michalkova, Veronika, Aksoy, Emre, Takac, Peter, Abd-Alla, Adly M. M., Malacrida, Anna R., Aksoy, Serap, and Attardo, Geoffrey M.
- Published
- 2016
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25. Sphingomyelinase Activity in Mother's Milk Is Essential for Juvenile Development: A Case from Lactating Tsetse Flies1
- Author
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Benoit, Joshua B., Attardo, Geoffrey M., Michalkova, Veronika, Takáč, Peter, Bohova, Jana, and Aksoy, Serap
- Published
- 2012
- Full Text
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26. The Homeodomain Protein Ladybird Late Regulates Synthesis of Milk Proteins during Pregnancy in the Tsetse Fly (Glossina morsitans).
- Author
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Attardo, Geoffrey M., Benoit, Joshua B., Michalkova, Veronika, Patrick, Kevin R., Krause, Tyler B., and Aksoy, Serap
- Subjects
- *
HOMEOBOX proteins , *MILK proteins , *CHEMICAL synthesis , *PREGNANCY complications , *TSETSE-flies - Abstract
Regulation of tissue and development specific gene expression patterns underlies the functional specialization of organs in multi-cellular organisms. In the viviparous tsetse fly (Glossina), the female accessory gland is specialized to generate nutrients in the form of a milk-like secretion to support growth of intrauterine larva. Multiple milk protein genes are expressed specifically in the female accessory gland and are tightly linked with larval development. Disruption of milk protein synthesis deprives developing larvae of nutrients and results in extended larval development and/or in abortion. The ability to cause such a disruption could be utilized as a tsetse control strategy. Here we identify and delineate the regulatory sequence of a major milk protein gene (milk gland protein 1:mgp1) by utilizing a combination of molecular techniques in tsetse, Drosophila transgenics, transcriptomics and in silico sequence analyses. The function of this promoter is conserved between tsetse and Drosophila. In transgenic Drosophila the mgp1 promoter directs reporter gene expression in a tissue and stage specific manner orthologous to that of Glossina. Analysis of the minimal required regulatory region of mgp1, and the regulatory regions of other Glossina milk proteins identified putative homeodomain protein binding sites as the sole common feature. Annotation and expression analysis of Glossina homeodomain proteins identified ladybird late (lbl) as being accessory gland/fat body specific and differentially expressed between lactating/non-lactating flies. Knockdown of lbl in tsetse resulted in a significant reduction in transcript abundance of multiple milk protein genes and in a significant loss of fecundity. The role of Lbl in adult reproductive physiology is previously unknown. These results suggest that Lbl is part of a conserved reproductive regulatory system that could have implications beyond tsetse to other vector insects such as mosquitoes. This system is critical for tsetse fecundity and provides a potential target for development of a reproductive inhibitor. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
27. Juvenile hormone and insulin suppress lipolysis between periods of lactation during tsetse fly pregnancy.
- Author
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Baumann, Aaron A., Benoit, Joshua B., Michalkova, Veronika, Mireji, Paul O., Attardo, Geoffrey M., Moulton, John K., Wilson, Thomas G., and Aksoy, Serap
- Subjects
- *
JUVENILE hormones , *LIPOLYSIS , *INSULIN , *LACTATION , *PREGNANCY , *TSETSE-flies - Abstract
Highlights: [•] Tsetse flies possess two juvenile hormone receptors, Methoprene-tolerant and germ cell expressed, similar to Drosophila. [•] Juvenile hormone and insulin promote lipid accumulation in tsetse flies. [•] Juvenile hormone and insulin leads to increased fat storage during non-lactating periods. [•] Our results indicate the insulin and juvenile hormone are key to nutritional mobilization during tsetse lactation. [Copyright &y& Elsevier]
- Published
- 2013
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28. Analysis of lipolysis underlying lactation in the tsetse fly, Glossina morsitans
- Author
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Attardo, Geoffrey M., Benoit, Joshua B., Michalkova, Veronika, Yang, Guangxiao, Roller, Ladislav, Bohova, Jana, Takáč, Peter, and Aksoy, Serap
- Subjects
- *
TSETSE-flies , *LIPOLYSIS , *LACTATION , *GLOSSINA morsitans , *LARVAL physiology , *ADIPOKINETIC hormone , *LIPID metabolism , *REPRODUCTION - Abstract
Abstract: Female tsetse flies undergo viviparous reproduction, generating one larva each gonotrophic cycle. Larval nourishment is provided by the mother in the form of milk secretions. The milk consists mostly of lipids during early larval development and shifts to a balanced combination of protein and lipids in the late larval instars. Provisioning of adequate lipids to the accessory gland is an indispensable process for tsetse fecundity. This work investigates the roles of Brummer lipase (Bmm) and the adipokinetic hormone (AKH)/adipokinetic hormone receptor (AKHR) systems on lipid metabolism and mobilization during lactation in tsetse. The contributions of each system were investigated by a knockdown approach utilizing siRNA injections. Starvation experiments revealed that silencing of either system results in prolonged female lifespan. Simultaneous suppression of bmm and akhr prolonged survival further than either individual knockdown. Knockdown of akhr and bmm transcript levels resulted in high levels of whole body lipids at death, indicating an inability to utilize lipid reserves during starvation. Silencing of bmm resulted in delayed oocyte development. Respective reductions in fecundity of 20 and 50% were observed upon knockdown of akhr and bmm, while simultaneous knockdown of both genes resulted in 80% reduction of larval production. Omission of one bloodmeal during larvigenesis (nutritional stress) after simultaneous knockdown led to almost complete suppression of larval production. This phenotype likely results from tsetse’s inability to utilize lipid reserves as loss of both lipolysis systems leads to accumulation and retention of stored lipids during pregnancy. This shows that both Bmm lipolysis and AKH/AKHR signaling are critical for lipolysis required for milk production during tsetse pregnancy, and identifies the underlying mechanisms of lipid metabolism critical to tsetse lactation. The similarities in the lipid metabolic pathways and other aspects of milk production between tsetse and mammals indicate that this fly could be used as a novel model for lactation research. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
29. Common structural features facilitate the simultaneous identification and quantification of the five most common juvenile hormones by liquid chromatography-tandem mass spectrometry.
- Author
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Ramirez, Cesar E., Nouzova, Marcela, Michalkova, Veronika, Fernandez-Lima, Francisco, and Noriega, Fernando G.
- Subjects
- *
LIQUID chromatography-mass spectrometry , *TANDEM mass spectrometry , *JUVENILE hormones , *HEMIPTERA - Abstract
This study reports the development and application of a liquid chromatography method coupled to electrospray tandem mass spectrometry (LC-MS/MS) for the identification and quantification of the five most common juvenile hormone (JH) homologs and methyl farnesoate (MF). The protocol allows the simultaneous analysis in a single LC run of JH I, JH II, JH III, JH III bisepoxide (JHB 3) and JH III skipped bisepoxide (JHSB 3). The identification of JHs is based on multiple reaction monitoring (MRM), using two of the most abundant fragmentation transitions for each hormone. Addition of deuterated JH III as an internal standard permits the absolute quantification of the different JHs. The JH homologs common structural features led to similar chromatographic behavior, as well as related fragmentation patterns, which facilitated the simultaneous detection of all the homologs in a single LC-MS/MS run. The protocol detects JHs in the low femtomole range, allowing often the analysis of JH in individual insects. Fragmentation of each of the JH homologs generates unique diagnostic ions that permitted the identification and quantification of JHs from samples of different species of Diptera, Lepidoptera, Heteroptera and Hymenoptera. Having a simple protocol, which can undisputedly determine the identity of the homologs present in a particular species, provides us with the opportunity to identify and quantify JHs existing in insects that are pests, vector of diseases or important research models. Image 1 • This protocol allows the simultaneous analysis in a single LC-MS/MS run of JH I, JH II, JH III, JHB3 and JHSB3. • The JH homologs common structural features led to similar chromatographic behavior, as well as related fragmentation patterns. • Addition of deuterated JH III as an internal standard permits the absolute quantification of the different JHs. • The protocol detects JHs in the low femtomole range, allowing often the analysis of JH in individual insects. • We identified and quantified JHs from samples of different species of Diptera, Lepidoptera, Heteroptera and Hymenoptera. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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30. Vitamin B6 generated by obligate symbionts is critical for maintaining proline homeostasis and fecundity in tsetse flies.
- Author
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Michalkova V, Benoit JB, Weiss BL, Attardo GM, and Aksoy S
- Subjects
- Animals, Gene Expression Profiling, Symbiosis, Transaminases biosynthesis, Tsetse Flies metabolism, Wigglesworthia physiology, Fertility, Homeostasis, Proline metabolism, Tsetse Flies microbiology, Tsetse Flies physiology, Vitamin B 6 metabolism, Wigglesworthia metabolism
- Abstract
The viviparous tsetse fly utilizes proline as a hemolymph-borne energy source. In tsetse, biosynthesis of proline from alanine involves the enzyme alanine-glyoxylate aminotransferase (AGAT), which requires pyridoxal phosphate (vitamin B6) as a cofactor. This vitamin can be synthesized by tsetse's obligate symbiont, Wigglesworthia glossinidia. In this study, we examined the role of Wigglesworthia-produced vitamin B6 for maintenance of proline homeostasis, specifically during the energetically expensive lactation period of the tsetse's reproductive cycle. We found that expression of agat, as well as genes involved in vitamin B6 metabolism in both host and symbiont, increases in lactating flies. Removal of symbionts via antibiotic treatment of flies (aposymbiotic) led to hypoprolinemia, reduced levels of vitamin B6 in lactating females, and decreased fecundity. Proline homeostasis and fecundity recovered partially when aposymbiotic tsetse were fed a diet supplemented with either yeast or Wigglesworthia extracts. RNA interference-mediated knockdown of agat in wild-type flies reduced hemolymph proline levels to that of aposymbiotic females. Aposymbiotic flies treated with agat short interfering RNA (siRNA) remained hypoprolinemic even upon dietary supplementation with microbial extracts or B vitamins. Flies infected with parasitic African trypanosomes display lower hemolymph proline levels, suggesting that the reduced fecundity observed in parasitized flies could result from parasite interference with proline homeostasis. This interference could be manifested by competition between tsetse and trypanosomes for vitamins, proline, or other factors involved in their synthesis. Collectively, these results indicate that the presence of Wigglesworthia in tsetse is critical for the maintenance of proline homeostasis through vitamin B6 production., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)
- Published
- 2014
- Full Text
- View/download PDF
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