scholarly journals Aedes aegypti SGS1 is critical for Plasmodium gallinaceum infection of both the mosquito midgut and salivary glands

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Bianca B. Kojin ◽  
Ines Martin-Martin ◽  
Helena R. C. Araújo ◽  
Brian Bonilla ◽  
Alvaro Molina-Cruz ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Life Cycle ◽  
Aedes Aegypti ◽  
Salivary Glands ◽  
Malaria Transmission ◽  
Parasite Development ◽  
Mosquito Vector ◽  
Plasmodium Gallinaceum ◽  
Mosquito Midgut

Abstract Background The invasion of the mosquito salivary glands by Plasmodium sporozoites is a critical step that defines the success of malaria transmission and a detailed understanding of the molecules responsible for salivary gland invasion could be leveraged towards control of vector-borne pathogens. Antibodies directed against the mosquito salivary gland protein SGS1 have been shown to reduce Plasmodium gallinaceum sporozoite invasion of Aedes aegypti salivary glands, but the specific role of this protein in sporozoite invasion and in other stages of the Plasmodium life cycle remains unknown. Methods RNA interference and CRISPR/Cas9 were used to evaluate the role of A. aegypti SGS1 in the P. gallinaceum life cycle. Results Knockdown and knockout of SGS1 disrupted sporozoite invasion of the salivary gland. Interestingly, mosquitoes lacking SGS1 also displayed fewer oocysts. Proteomic analyses confirmed the abolishment of SGS1 in the salivary gland of SGS1 knockout mosquitoes and revealed that the C-terminus of the protein is absent in the salivary gland of control mosquitoes. In silico analyses indicated that SGS1 contains two potential internal cleavage sites and thus might generate three proteins. Conclusion SGS1 facilitates, but is not essential for, invasion of A. aegypti salivary glands by P. gallinaceum and has a dual role as a facilitator of parasite development in the mosquito midgut. SGS1 could, therefore, be part of a strategy to decrease malaria transmission by the mosquito vector, for example in a transgenic mosquito that blocks its interaction with the parasite.

scholarly journals Intra-annual climate variability and malaria transmission in Nigeria

2013 ◽  
Vol 21 (21) ◽  
pp. 7-19 ◽  
Author(s):  
Ayansina Ayanlade ◽  
Nathaniel Olugbade Adeoye ◽  
Oyekanmi Babatimehin
Keyword(s):  
Life Cycle ◽  
Relative Humidity ◽  
Climate Variability ◽  
Malaria Transmission ◽  
Malaria Parasite ◽  
Early Warning Systems ◽  
Egg Laying ◽  
Parasite Development ◽  
Mosquito Vector ◽  
Epidemiologic Surveillance

Abstract This study develops an integrated innovation for malaria early warning systems (MEWS), based on vulnerability monitoring, seasonal climate variability data, and epidemiologic surveillance. The main aim of the study is to examine the relationship between intra-annual climate variability and malaria transmission in Nigeria. For this study, climatic conditions considered suitable for the development of the malaria parasite and its transmission through the mosquito stage of its life cycle are temperatures within the range from 18°C to 32°C. Below 18°C the parasite development decreases significantly, while above 32°C the survival of the mosquito is compromised. Relative humidity greater than 60% is also considered a requirement for the mosquito to survive long enough for the parasite to develop sufficiently to be transmitted to its human host stage. The research findings show that seasonality of climate greatly influences the seasonality of malaria transmission. Specifically, rainfall plays an important role in the distribution and maintenance of breeding sites for the mosquito vector. Rainfall and surface water is required for the egg laying and larval stages of the mosquito life cycle and monthly rainfall above 80 mm is considered a requirement. Also, it is temperature that regulates the development rate of both the mosquito larvae and the malaria parasite (Plasmodium species) within the mosquito host. Relative humidity and temperature play an important role in the survival and longevity of the mosquito vector. This study is in conformity with the findings of the IPCC (2001) that malaria is caused by four distinct species of the Plasmodium parasite, transmitted by mosquitoes of the genus Anopheles, which are most abundant in tropical/subtropical regions, although they are also found in limited numbers in temperate climates.

scholarly journals Distinct Roles of Hemocytes at Different Stages of Infection by Dengue and Zika Viruses in Aedes aegypti Mosquitoes

2021 ◽  
Vol 12 ◽  
Author(s):  
Thiago H. J. F. Leite ◽  
Álvaro G. A. Ferreira ◽  
Jean-Luc Imler ◽  
João T. Marques
Keyword(s):  
Aedes Aegypti ◽  
Cellular Responses ◽  
Innate Immune ◽  
Mosquito Vector ◽  
Phagocytic Function ◽  
Systemic Dissemination ◽  
Latex Beads ◽  
Medical Importance ◽  
Immune Pathways

Aedes aegypti mosquitoes are vectors for arboviruses of medical importance such as dengue (DENV) and Zika (ZIKV) viruses. Different innate immune pathways contribute to the control of arboviruses in the mosquito vector including RNA interference, Toll and Jak-STAT pathways. However, the role of cellular responses mediated by circulating macrophage-like cells known as hemocytes remains unclear. Here we show that hemocytes are recruited to the midgut of Ae. aegypti mosquitoes in response to DENV or ZIKV. Blockade of the phagocytic function of hemocytes using latex beads induced increased accumulation of hemocytes in the midgut and a reduction in virus infection levels in this organ. In contrast, inhibition of phagocytosis by hemocytes led to increased systemic dissemination and replication of DENV and ZIKV. Hence, our work reveals a dual role for hemocytes in Ae. aegypti mosquitoes, whereby phagocytosis is not required to control viral infection in the midgut but is essential to restrict systemic dissemination. Further understanding of the mechanism behind this duality could help the design of vector-based strategies to prevent transmission of arboviruses.

scholarly journals Characterization of a vasodilator from the salivary glands of the yellow fever mosquito Aedes aegypti

1992 ◽  
Vol 165 (1) ◽  
pp. 61-71 ◽  
Author(s):  
J. M. Ribeiro
Keyword(s):  
Salivary Gland ◽  
Aedes Aegypti ◽  
Salivary Glands ◽  
Posterior Part ◽  
Aortic Ring ◽  
Blood Feeding ◽  
Reversed Phase ◽  
Relative Molecular Mass ◽  
Vasodilatory Activity ◽  
Carboxy Terminal

Salivary gland homogenates and oil-induced saliva of the mosquito Aedes aegypti dilate the rabbit aortic ring and contract the guinea pig ileum. The vasodilatory activity is endothelium-dependent, heat-stable, sensitive to both trypsin and chymotrypsin treatments, and both smooth muscle activities cross-desensitize to the tachykinin peptide substance P. Both bioactivities co-elute when salivary gland homogenates are fractionated by reversed-phase HPLC. Molecular sieving chromatography indicates a relative molecular mass of 1400. A monoclonal antibody specific to the carboxy terminal region of tachykinins reacts with material in the posterior part of the central lobe of paraformaldehyde-fixed salivary glands. The presence of a vasodilatory peptide of the tachykinin family in the salivary glands of A. aegypti is proposed and its role in blood feeding is discussed.

The aminergic and peptidergic innervation of insect salivary glands

1997 ◽  
Vol 200 (14) ◽  
pp. 1941-1949 ◽  
Author(s):  
D Ali
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Physiological Role ◽  
Salivary Secretion ◽  
Stick Insect ◽  
Stomatogastric Nervous System ◽  
Related Family ◽  
Aminergic Innervation ◽  
Peptidergic Innervation

Insect salivary glands are glands associated with nutrient intake whose secretions are generally involved in the digestion and lubrication of food. They are under the control of neuroactive substances and may be innervated from several sources including the suboesophageal ganglion, the stomatogastric nervous system and the unpaired median nerves. Both amines and peptides have been suggested to play roles in the control of insect salivation, as indicated by their association with terminals on salivary glands, their effects in salivary gland bioassays and their ability to alter second messenger levels and ion channel conformations. Serotonin and dopamine appear to be the most prominent amines associated with insect salivary glands. Either one or both of these amines are found associated with the salivary glands of the locust, stick insect, cockroach, cricket, dragonfly, mosquito, adult moth and kissing bug. Their roles, although not fully elucidated, appear to be in the control of salivary secretion. Several peptides, including members of the FMRFamide-related family of peptides, are also found associated with insect salivary glands. Sources of peptidergic innervation are as varied as those for aminergic innervation, but information regarding the physiological role of these peptides is lacking. The relevance of the different levels of complexity of salivary gland innervation, which range from the absence of innervation in some species (blowfly) to the presence of several distinct sources in others (locust, cockroach), is not well understood. This review serves to consolidate what is known of the phenotype of salivary neurones in relation to the control of salivation.

scholarly journals Experimental life cycle of Lagochilascaris minor Leiper, 1909

1992 ◽  
Vol 34 (4) ◽  
pp. 277-287 ◽  
Author(s):  
Dulcinéa Maria Barbosa Campos ◽  
Lindomar G. Freire Filha ◽  
Miguel Alípio Vieira ◽  
Julieta Machado Paçô ◽  
Moacir A. Maia
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Subcutaneous Tissue ◽  
Cervical Region ◽  
Parasite Development ◽  
Mature Stage ◽  
Post Inoculation ◽  
Skeletal Musculature ◽  
Third Stage

The life cycle of Lagochilascaris minor was studied using material collected from human lesion and applying the experimental model: rodents (mice, hamsters), and carnivorae (cats, dogs). In mice given infective eggs, orally, hatch of the third stage larvae was noted in the gut wall, with migration to liver, lungs, skeletal musculature and subcutaneous tissue becoming, soon after, encysted. In cats infected with skinned carcasses of mice (60 to 235 days of infection) it was observed: hatch of third stage larvae from the nodules (cysts) in the stomach, migration through the oesophagus, pharynx, trachea, related tissues (rhino-oropharynx), and cervical lymphonodes developing to the mature stage in any of these sites on days 9-20 post inoculation (P.I.). There was no parasite development up to the mature stage in cats inoculated orally with infective eggs, which indicates that the life cycle of this parasite includes an obligatory intermediate host. In one of the cats (fed carcass of infected mice) necropsied on day 43 P.I., it was observed the occurence of the self-infective cycle of L. minor in the lung tissues and in the cervical region which was characterized by the finding of eggs in different stages of development, third stage larvae and mature worms. It's believed that some component of the carnivorae gastrointestinal tracts may preclude the development of third stage larvae from L. minor eggs what explains the interruption of the life cycle in animals fed infective eggs. It's also pointed out the role of the intermediate host in the first stages of the life cycle of this helminth.

scholarly journals Mature salivary gland rests within sonic hedgehog–positive medulloblastoma: case report and insights into the molecular genetics and embryopathology of ectopic intracranial salivary gland analogs

2016 ◽  
Vol 18 (6) ◽  
pp. 708-712 ◽  
Author(s):  
Berje Shammassian ◽  
Sunil Manjila ◽  
Efrem Cox ◽  
Kaine Onwuzulike ◽  
Dehua Wang ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Case Report ◽  
Salivary Glands ◽  
Molecular Genetics ◽  
Posterior Fossa ◽  
Sonic Hedgehog ◽  
Unique Case ◽  
Cerebellar Medulloblastoma ◽  
Disseminated Disease

Intracranial ectopic salivary gland rests within dural-based lesions are reported very infrequently in the literature. The authors report the unique case of a 12-year-old boy with a cerebellar medulloblastoma positive for sonic hedgehog (Shh) that contained intraaxial mature ectopic salivary gland rests. The patient underwent clinical and radiological monitoring postoperatively, until he died of disseminated disease. An autopsy showed no evidence of salivary glands within disseminated lesions. The intraaxial presence of salivary gland rests and concomitant Shh positivity of the described tumor point to a disorder in differentiation as opposed to ectopic developmental foci, which are uniformly dural based in the described literature. The authors demonstrate the characteristic “papilionaceous” appearance of the salivary glands with mucicarmine stain and highlight the role of Shh signaling in explaining the intraaxial presence of seromucous gland analogs. This article reports the first intraaxial posterior fossa tumor with heterotopic salivary gland rests, and it provides molecular and embryopathological insights into the development of these lesions.

scholarly journals PIMMS43 is required for malaria parasite immune evasion and sporogonic development in the mosquito vector

2020 ◽  
Vol 117 (13) ◽  
pp. 7363-7373 ◽  
Author(s):  
Chiamaka V. Ukegbu ◽  
Maria Giorgalli ◽  
Sofia Tapanelli ◽  
Luisa D. P. Rona ◽  
Amie Jaye ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Immune Evasion ◽  
Malaria Parasite ◽  
Surface Protein ◽  
Innate Immune ◽  
Mosquito Vector ◽  
Anopheles Coluzzii ◽  
Innate Immune Responses ◽  
New Host ◽  
Mosquito Midgut

After being ingested by a female Anopheles mosquito during a bloodmeal on an infected host, and before they can reach the mosquito salivary glands to be transmitted to a new host, Plasmodium parasites must establish an infection of the mosquito midgut in the form of oocysts. To achieve this, they must first survive a series of robust innate immune responses that take place prior to, during, and immediately after ookinete traversal of the midgut epithelium. Understanding how parasites may evade these responses could highlight new ways to block malaria transmission. We show that an ookinete and sporozoite surface protein designated as PIMMS43 (Plasmodium Infection of the Mosquito Midgut Screen 43) is required for parasite evasion of the Anopheles coluzzii complement-like response. Disruption of PIMMS43 in the rodent malaria parasite Plasmodium berghei triggers robust complement activation and ookinete elimination upon mosquito midgut traversal. Silencing components of the complement-like system through RNAi largely restores ookinete-to-oocyst transition but oocysts remain small in size and produce a very small number of sporozoites that additionally are not infectious, indicating that PIMMS43 is also essential for sporogonic development in the oocyst. Antibodies that bind PIMMS43 interfere with parasite immune evasion when ingested with the infectious blood meal and significantly reduce the prevalence and intensity of infection. PIMMS43 genetic structure across African Plasmodium falciparum populations indicates allelic adaptation to sympatric vector populations. These data add to our understanding of mosquito–parasite interactions and identify PIMMS43 as a target of malaria transmission blocking.

Gastropod predation sites: the role of predator and prey in chemical attraction of the hermit crab Clibanarius vittatus

1990 ◽  
Vol 70 (3) ◽  
pp. 583-596 ◽  
Author(s):  
D. Rittschof ◽  
C.M. Kratt ◽  
A.S. Clare
Keyword(s):  
Salivary Gland ◽  
Ionic Strength ◽  
Salivary Glands ◽  
Hermit Crab ◽  
Sea Water ◽  
Hermit Crabs ◽  
Muscle Proteins ◽  
Clibanarius Vittatus ◽  
Low Ionic Strength

Gastropod shells are essential to most hermit crabs. Shell availability limits hermit crab populations. Shells provide protection and the degree of shell-fit controls crab growth and fecundity. Crabs locate new gastropod shells from a distance under water by molecules released from gastropod flesh during predation events. Here we test the hypothesis that the salivary glands of the predatory gastropod are the source of enzymes that digest muscle proteins and release peptide attractants. We describe the anatomy of both the acinous salivary glands and the tubular accessory salivary glands of Busycon contrarium which are similar to those of B. carica. The salivary gland ducts empty at the mouth, suggesting a role in the primary digestion of food. We show that gastropod muscle proteins, extracted by salt solutions with the ionic strength of sea water and purified by precipitation in low ionic strength can be digested by gastropod salivary gland enzymes to generate peptides attractive to the hermit crab, Clibanarius vittatus, in field assays.

Effects of Plasmodium gallinaceum on hemolymph physiology of Aedes aegypti during parasite development

2011 ◽  
Vol 57 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Ricardo Vieira Araujo ◽  
Ceres Maciel ◽  
Klaus Hartfelder ◽  
Margareth Lara Capurro
Keyword(s):  
Aedes Aegypti ◽  
Parasite Development ◽  
Plasmodium Gallinaceum

scholarly journals Effects of Local and Systemic Immune Challenges on the Expression of Selected Salivary Genes in the Malaria Mosquito Anopheles coluzzii

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1300
Author(s):  
Giulia Bevivino ◽  
Bruno Arcà ◽  
Fabrizio Lombardo
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Antimicrobial Properties ◽  
Transcript Abundance ◽  
Structural Features ◽  
Anopheles Coluzzii ◽  
Transcriptional Modulation ◽  
Immune Challenges

Salivary glands play a crucial tripartite role in mosquito physiology. First, they secrete factors that greatly facilitate both sugar and blood meal acquisition. Second, the transmission of pathogens (parasites, bacteria and viruses) to the vertebrate host requires both the recognition and invasion of the salivary glands. Third, they produce immune factors that both protect the organ from invading pathogens and are also able to exert their activity in the crop and the midgut when saliva is re-ingested during feeding. Studies on mosquito sialomes have revealed the presence of several female and/or male salivary gland-specific or enriched genes whose function is completely unknown so far. We focused our attention on these orphan genes, and we selected, according to sequence and structural features, a shortlist of 11 candidates with potential antimicrobial properties. Afterwards, using qPCR, we investigated their expression profile at 5 and 24 h after an infectious sugar meal (local challenge) or thoracic microinjection (systemic challenge) of Gram-negative (Escherichia coli, EC) or Gram-positive (Staphylococcus aureus, SA) bacteria. We observed a general increase in the transcript abundance of our salivary candidates between 5 and 24 h after local challenge. Moreover, transcriptional modulation was determined by the nature of the stimulus, with salivary gland-enriched genes (especially hyp15 upon SA stimulus) upregulated shortly after the local challenge and later after the systemic challenge. Overall, this work provides one of the first contributions to the understanding of the immune role of mosquito salivary glands. Further characterization of salivary candidates whose expression is modulated by immune challenge may help in the identification of possible novel antimicrobial peptides.

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