Nitric Oxide Binding and Crystallization of Recombinant Nitrophorin I, a Nitric Oxide Transport Protein from the Blood-Sucking Bug Rhodnius prolixus
John F. AndersenDonald E. ChampagneA. WeichselJosé M. C. RibeiroCelia A. BalfourVirginia M. DressW.R. Montfort
87
Citation
7
Reference
10
Related Paper
Citation Trend
Abstract:
A nitric oxide transport protein (nitrophorin I) from the salivary glands of the blood-sucking bug Rhodnius prolixus has been expressed as an insoluble form in Escherichia coli, reconstituted with heme, and characterized with respect to NO binding kinetics and equilibria. NO binding and absorption spectra for recombinant nitrophorin I were indistinguishable from those of the insect-derived protein. The degree of NO binding, the rate of NO release, and the Soret absorption maxima for nitrophorin I were all pH dependent. The NO dissociation constant rose 9-fold over the pH range 5.0−8.3 , from 0.19 × 10-6 to 1.71 × 10-6. The NO dissociation rate rose 2500-fold between pH 5.0 and pH 8.3, from 1.2 × 10-3 to 3.0 s-1. Thus, the NO association rate must also be pH dependent and reduced at pH 5.0 by ∼280-fold. These factors are consistent with nitrophorin function: NO storage in the apparent low pH of insect salivary glands and NO release into the tissue of the insect's host, where vasodilation is induced. The reversible nature of NO binding, which does not occur with most other heme proteins, and the apparent kinetic control of NO release are discussed. We also report crystals of nitrophorin I that are suitable for structure determination by X-ray crystallography. The most promising crystal form contains two protein molecules in the asymmetric unit and diffracts beyond 2.0 Å resolution.Experiments were done to test the possibility and frequency of direct transmission of trypanosomes between different stages of Rhodnius prolixus . It was found that direct transmission of Trypanosoma cruzi between individuals of Rhodnius prolixus is not uncommon, and more frequent when the non-infected bugs are hungry. The mechanism of transmission is probably by taking a blood meal from other engorged individuals and by ingestion of feces from infected bugs. No direct transmission of Trypanosoma rangeli between bugs was observed.
Rhodnius
Blood meal
Chagas Disease
Cite
Citations (14)
INTRODUCTION: Behavioral fever is a response to infections with microorganisms observed in some poikilothermic animals. Rhodnius prolixus is involved in the transmission of two parasites: Trypanosoma cruzi (pathogenic for humans and transmitted in feces) and Trypanosoma rangeli (non-pathogenic for humans, pathogenic for Rhodnius and transmitted by the bite of an infected individual). Only T. rangeli is found in the hemolymph of Rhodnius as it travels to the salivary glands. METHODS: To study vector-parasite interactions, we evaluated possible behavioral fever responses of R. prolixus to intracoelomic inoculation with T. cruzi or T. rangeli. Temperature preferences of fifth-instar nymphs of R. prolixus were evaluated after inoculation with T. rangeli KP1(+), KP1(-), T. cruzi I, or the Trypanosome culture medium. Four different fixed temperatures (25, 30, 35, and 40°C) in two simultaneous experiments (enclosed and free-moving insects) were evaluated. Free-moving insects were marked daily according to their temperature preferences on each of the 15 days after inoculation. Numbers of insects in each temperature shelter and daily mortality were compared with those enclosed shelters of different temperatures. RESULTS: Rhodnius prolixus inoculated with both strains of T. rangeli and with the trypanosome culture medium showed preferences for the lowest temperatures (25°C). However, R. prolixus inoculated with T. cruzi I showed significant preferences for temperatures around 35°C. CONCLUSIONS: This is the first known investigation to demonstrate a behavioral fever response in R. prolixus injected intracoelomically with T. cruzi I.
Rhodnius
Hemolymph
Xenodiagnosis
Triatominae
Triatoma infestans
Chagas Disease
Cite
Citations (13)
Rhodnius
Cite
Citations (5)
A previous study by Davey [Can J Zool 4:243–249 (1987)] showed that egg production in the blood-feeding insect Rhodnius prolixus is greatly enhanced when the corpus allatum (CA) is denervated. This result supported findings of others that the brain of Rhodnius imposes an inhibition on the CA via its connections to the CA. The present study identifies the nervus corporis cardiacum II (NCCII) as the nerve responsible for this inhibitory influence. Transecting the NCCII before feeding causes a dramatic increase in the number of eggs made. Since the NCCII is a relatively small nerve that may contain only axons of lateral and posterior neurosecretory cells in the protocerebrum, this result suggests that one or both of these cell types produce the brain factor inhibiting egg production in this insect. Arch. Insect Biochem. Physiol. 39:126–131, 1998. © 1998 Wiley-Liss, Inc.
Corpus allatum
Rhodnius
Blood meal
Cite
Citations (0)
A previous study by Davey [Can J Zool 4:243–249 (1987)] showed that egg production in the blood-feeding insect Rhodnius prolixus is greatly enhanced when the corpus allatum (CA) is denervated. This result supported findings of others that the brain of Rhodnius imposes an inhibition on the CA via its connections to the CA. The present study identifies the nervus corporis cardiacum II (NCCII) as the nerve responsible for this inhibitory influence. Transecting the NCCII before feeding causes a dramatic increase in the number of eggs made. Since the NCCII is a relatively small nerve that may contain only axons of lateral and posterior neurosecretory cells in the protocerebrum, this result suggests that one or both of these cell types produce the brain factor inhibiting egg production in this insect. Arch. Insect Biochem. Physiol. 39:126–131, 1998. © 1998 Wiley-Liss, Inc.
Corpus allatum
Rhodnius
Blood meal
Arthropod
Blood sucking
Cite
Citations (10)
Epidemiological studies performed in El Salvador between 1955-1972 demonstrated a high frequency of two triatomine vectors (Triatoma dimidiata and Rhodnius prolixus). However, the frequency of R. prolixus decreased by 1976 and this species has not been found since 1995. The main factors influencing the elimination of R. prolixus in El Salvador are discussed in this paper.
Rhodnius
Triatominae
Cite
Citations (21)
Azadirachtin
Rhodnius
Chagas Disease
Cite
Citations (2)
1. The growth and development of normal and sterile (i.e. symbiont-free) Rhodnius prolixus are compared. The last three instars of sterile bugs weigh less than normal ones. Sterile insects completed the first three stages of their life-histories in less time than normal insects, and at the fourth stage, nutritional deficiencies had profound effects on their further development. 2. The sensitivity of the Rhodnius symbionts, Nocardia rhodnii, to five antibiotic substances is determined. Terramycin, aureomycin and chloramphenicol are effective inhibitors. 3. The symbiotic condition in Rhodnius and the related bug, Triatoma infestans, is discussed.
Rhodnius
Triatoma infestans
Triatominae
Cite
Citations (39)
Rhodnius
Blood meal
Pronase
Cite
Citations (32)
Rhodnius
Chagas Disease
Kinetoplastida
Cite
Citations (29)