Perez De Leon - Academia.edu (original) (raw)

Papers by Perez De Leon

Archives of Insect Biochemistry and Physiology, 2016

Emerging and re‐emerging tick‐borne diseases threaten public health and the wellbeing of domestic... more Emerging and re‐emerging tick‐borne diseases threaten public health and the wellbeing of domestic animals and wildlife globally. The adoption of an evolutionary ecology framework aimed to diminish the impact of tick‐borne diseases needs to be part of strategies to protect human and animal populations. We present a review of current knowledge on the adaptation of ticks to their environment, and the impact that global change could have on their geographic distribution in North America. Environmental pressures will affect tick population genetics by selecting genotypes able to withstand new and changing environments and by altering the connectivity and isolation of several tick populations. Research in these areas is particularly lacking in the southern United States and most of Mexico with knowledge gaps on the ecology of these diseases, including a void in the identity of reservoir hosts for several tick‐borne pathogens. Additionally, the way in which anthropogenic changes to landsca...

Parasites & Vectors, 2010

Background Tick parasitism is a major impediment for cattle production in many parts of the world... more Background Tick parasitism is a major impediment for cattle production in many parts of the world. The southern cattle tick, Rhipicephalus (Boophilus) microplus, is an obligate hematophagous parasite of domestic and wild animals that serves as vector of infectious agents lethal to cattle. Tick saliva contains molecules evolved to modulate host innate and adaptive immune responses which facilitates blood feeding and pathogen transmission. Tick feeding promotes CD4 T cell polarization to a Th2 profile usually accompanied by down-regulation of Th1 cytokines through as yet undefined mechanisms. Co-stimulatory molecules on antigen presenting cells are central to development of T cell responses including Th1 and Th2 responses. Tick induced changes to antigen presenting cell signal transduction pathways are largely unknown. Here we document the ability of R. microplus salivary gland extracts (SGE) to effect differential CD86 expression. Results We examined changes in co-stimulatory molecul...

Revista Mexicana de Ciencias Pecuarias, 2012

We review recent progress for control of Rhipicephalus (Boophilus) microplus and R. (B.) annulatu... more We review recent progress for control of Rhipicephalus (Boophilus) microplus and R. (B.) annulatus. Outbreak infestations in the U.S. have reached alarming levels, due to increased populations of deer and other ungulates serving as alternative hosts. GIS mapping of infestations and deer habitat aids in utilizing methods and equipment designed for acaricide treatment of wild ungulates. Investigations include deer immunology, tick molecular genetics, acaricide resistance, and host-parasite interactions with deer or cattle, ticks, and pathogens. Acaricide resistance is widespread in Mexico and U.S. dipping vats depend on organophosphate (OP) inhibition of acetylcholinesterase (AChE). Three cDNAs putatively encoding acetylcholinesterases (AChE, E.C. 3.1.1.7) in R. (B.) microplus were expressed in the baculovirus system and exhibited Km values for acetylthiocholine of approx. 5, 50, or 90 µM, for rBmAChE1, rBmAChE2, and rBmAChE3, respectively. The rBmAChEs exhibited substrate preference ...

G3 (Bethesda, Md.), Jan 30, 2018

Haematobia irritans, commonly known as the horn fly, is a globally distributed blood-feeding pest... more Haematobia irritans, commonly known as the horn fly, is a globally distributed blood-feeding pest of cattle that is responsible for significant economic losses to cattle producers. Chemical insecticides are the primary means for controlling this pest but problems with insecticide resistance have become common in the horn fly. To provide a foundation for identification of genomic loci for insecticide resistance and for discovery of new control technology, we report the sequencing, assembly, and annotation of the horn fly genome. The assembled genome is 1.14 Gb, comprising 76,616 scaffolds with N50 scaffold length of 23 Kb. Using RNA-Seq data, we have predicted 34,413 gene models of which 19,185 have been assigned functional annotations. Comparative genomics analysis with the Dipteran flies Musca domestica L., Drosophila melanogaster, and Lucilia cuprina, show that the horn fly is most closely related to M. domestica, sharing 8,748 orthologous clusters followed by D. melanogaster and L. cuprina, sharing 7,582 and 7,490 orthologous clusters respectively. We also identified a gene locus for the sodium channel protein in which mutations have been previously reported that confers target site resistance to the most common class of pesticides used in fly control. Additionally, we identified 276 genomic loci encoding members of metabolic enzyme gene families such as cytochrome P450s, esterases and glutathione S-transferases, and several genes orthologous to sex determination pathway genes in other Dipteran species. KEYWORDS horn fly sex determination genes pesticide resistance metabolic resistance The horn fly, Haematobia irritans, is one of the most widespread and economically important ectoparasites of cattle in the world. The fly is found in Europe, Africa, Asia, and the Americas, imparting significant discomfort to cattle and economic impact to cattle producers. The entire life cycle of the horn fly is centered upon cattle, as eggs are laid in fresh manure wherein larvae and pupae develop, after which the adult fly emerges and immediately begins feeding upon a bovine host. The adult fly is hematophageous, feeding 20-40 times per day, primarily upon cattle. Economic impact of the horn fly has been estimated at US $2.5 billion annual losses in Brazil alone (Grisi et al. 2014). Control of this pest relies upon the use of insecticides, but resistance to the most commonly available products in the pyrethroid and organophosphate classes is a major problem leading to control failures (Guerrero and Barros 2006; Jamroz et al. 1998; Barros et al. 2001). The effects of climate change and global warming have been predicted to increase the fly's economic impact upon the U. S. cattle and the cattle industry, particularly in the Northern states (Schmidtmann and Miller 1989).

Molecular ecology, Jan 9, 2017

Ecological specialization to restricted diet-niches is driven by obligate, and often maternally i... more Ecological specialization to restricted diet-niches is driven by obligate, and often maternally inherited, symbionts in many arthropod lineages. These heritable symbionts typically form evolutionarily stable associations with arthropods that can last for millions of years. Ticks were recently found to harbor such an obligate symbiont, Coxiella-LE, that synthesizes B vitamins and cofactors not obtained in sufficient quantities from blood diet. In this study, the examination of 81 tick species show that some Coxiella-LE symbioses are evolutionarily stable with an ancient acquisition followed by co-diversification as observed in ticks belonging to the Rhipicephalus genus. However, many other Coxiella-LE symbioses are characterized by low evolutionary stability with frequent host shifts and extinction events. Further examination revealed the presence of nine other genera of maternally inherited bacteria in ticks. Although these nine symbionts were primarily thought to be facultative, th...

Data in brief, 2016

The New World Screwworm (NWS), Cochliomyia hominivorax, is a pest insect that is endemic to subtr... more The New World Screwworm (NWS), Cochliomyia hominivorax, is a pest insect that is endemic to subtropical and tropical regions of the Western Hemisphere. The female lays eggs in open wounds or orifices of warm-blooded animals. Upon hatching, the resulting larvae feed upon the host׳s living tissues, which can become infected and death can occur. The sterile insect technique was developed to eradicate this pest from North America and new female conditional-lethal strains that generate only male individuals are being developed for use in the eradication program. To facilitate the identification of useful transcripts and gene promoters for these new strains, we used an Illumina Hi-Seq protocol to sequence the testes transcriptome of NWS. We report the assembly of 4149 transcripts (≥200 nt) from testes dissected from NWS males obtained from the J06 strain used in the screwworm production plant in Pacora, Panama. Functional annotation resulted in 2060, 2031, 558, and 325 transcripts with as...

Though eradicated from the US for the past half century, reemergence of populations of southern c... more Though eradicated from the US for the past half century, reemergence of populations of southern cattle tick, Rhipicephalus (Boophilus) microplus, and cattle-fever tick, R. (B). annulatus which transmit the blood parasites that cause lethal cattle disease, is of major concern. Given that the key management area of Rhipicephalus ticks in south Texas overlap with the densest infestations of invasive giant reed (Arundo donax L.) in the US, we determine whether giant reed invasions are positively or negatively associated with survival of ticks. We look at tick survivorship and reproduction in three common riparian habitats: native forests, arundo stands, and pastures of exotic buffelgrass. Engorged females in the three habitats were likely to lay eggs and larger masses in arundo and native forests when compared to ticks in buffelgrass where daily temperatures were higher. Average high temperatures predicted the proportion of egg laying ticks (b=-15.81, t(8)=25.74, p

The polar cuticular lipids of the Old World sand fly, Phlebotomus papatasi, were analyzed by high... more The polar cuticular lipids of the Old World sand fly, Phlebotomus papatasi, were analyzed by high resolution mass spectrometry. Blood-fed females, non-blood-fed females and males were separately analyzed and compared. The major polar cuticular lipids were found to be long-chain diols and fatty acids. Relatively high levels of diacylglycerols were found in blood-fed females and in males. A wide variety of lipids were found at low levels, including esters, sterols, monoacylglycerols, and hydroxy fatty acids. Blood-fed females had several lyso lipids and N-acyl amino acids that were not found on unfed females or males. These substances may be surfactants used in blood-feeding. Heneicosanoic acid was found on females at more than twice the level of males, suggesting it could be a component of a previously-described female aggregation pheromone. Four substances were identified on males at two-fold higher levels than on females: tetradienoic acid, methoxyhexadecasphinganine, butyl octadec...

Revista Brasileira de Parasitologia Veterinária, 2011

This study was conducted to obtain an epidemiological view of acaricide resistance in populations... more This study was conducted to obtain an epidemiological view of acaricide resistance in populations of Rhipicephalus (Boophilus) microplus in the State of Mato Grosso do Sul. Twenty-four tick samples were collected from municipalities in the State where farmers had reported concerns about resistance to or failure of tick control. These ticks were subjected to in vitro resistance detection assays using the adult immersion test (AIT). The efficacy of alpha-cypermethrin, cypermethrin and amitraz treatments on samples collected throughout the State was generally poor. AIT showed efficacy > 90% from the use of DDVP + chlorfenvinphos) (20 out of 21 municipalities), dichlorvos + cypermethrin (10 out of 16 municipalities) and cypermethrin + citronella + chlorpyrifos + piperonyl butoxide (20 out of 21 municipalities). PCR assays were used to detect the presence of pyrethroid resistance-associated sodium channel gene mutation. Larvae from three different populations that had previously been ...

Veterinary Parasitology, 2013

Five strains of Rhipicephalus (Boophilus) microplus collected from Tamaulipas Mexico were tested ... more Five strains of Rhipicephalus (Boophilus) microplus collected from Tamaulipas Mexico were tested for resistance against several classes of acaricides commonly used. All were resistant to fipronil. Four of five were co-resistant to permethrin and coumaphos in addition to being resistant to fipronil. One strain, El Zamora was found multi-resistant to permethrin, coumaphos, fipronil, and amitraz. Selection with fipronil for 3 generations produced a resistance ratio of 8.3 and 9.4 at the LC 50 and the LC 99 estimates, respectively. Permethrin resistance in El Zamora was possibly linked to elevated esterase (CZEST9) and could be a contributing factor of resistance to fipronil. The implications of resistance for the control of the southern cattle tick in the future are discussed.

Parasites & Vectors, 2010

Background Babesia are emerging health threats to humans and animals in the United States. A coll... more Background Babesia are emerging health threats to humans and animals in the United States. A collaborative effort of multiple disciplines to attain optimal health for people, animals and our environment, otherwise known as the One Health concept, was taken during a research workshop held in April 2009 to identify gaps in scientific knowledge regarding babesioses. The impetus for this analysis was the increased risk for outbreaks of bovine babesiosis, also known as Texas cattle fever, associated with the re-infestation of the U.S. by cattle fever ticks. Results The involvement of wildlife in the ecology of cattle fever ticks jeopardizes the ability of state and federal agencies to keep the national herd free of Texas cattle fever. Similarly, there has been a progressive increase in the number of cases of human babesiosis over the past 25 years due to an increase in the white-tailed deer population. Human babesiosis due to cattle-associated Babesia divergens and Babesia divergens-like...

Journal of Medical Entomology, 2011

Frontiers in Plant Science, Dec 15, 2022

Background: Huanglongbing (HLB, yellow shoot disease) is a highly destructive citrus disease asso... more Background: Huanglongbing (HLB, yellow shoot disease) is a highly destructive citrus disease associated with a nonculturable bacterium, "Candidatus Liberibacter asiaticus" (CLas), which is transmitted by Asian citrus psyllid (ACP, Diaphorina citri). In Mexico, HLB was first reported in Tizimin, Yucatań, in 2009 and is now endemic in 351 municipalities of 25 states. Understanding the population diversity of CLas is critical for HLB management. Current CLas diversity research is exclusively based on analysis of the bacterial genome, which composed two regions, chromosome (> 1,000 genes) and prophage (about 40 genes). Methods and results: In this study, 40 CLas-infected ACP samples from 20 states in Mexico were collected. CLas was detected and confirmed by PCR assays. A prophage gene(terL)-based typing system (TTS) divided the Mexican CLas strains into two groups: Term-G including four strains from Yucatań and Chiapas, as well as strain psy62 from Florida, USA, and Term-A included all other 36 Mexican strains, as well as strain AHCA1 from California, USA. CLas diversity was further evaluated to include all chromosomal and prophage genes assisted by using machine learning (ML) tools to resolve multidimensional data handling issues. A Term-G strain (YTMX) and a Term-A strain (BCSMX) were sequenced and analyzed. The two Mexican genome sequences along with the CLas genome sequences available in GenBank were studied. An unsupervised ML was implemented through principal component analysis (PCA) on average nucleotide identities (ANIs) of CLas whole genome sequences; And a supervised ML was implemented through sparse partial least squares Frontiers in Plant Science frontiersin.org 01

Subtropical Agriculture and Environments, 2016

Arundo donax, giant reed is an invasive weed in the riparian habitats of the Rio Grande Basin. A ... more Arundo donax, giant reed is an invasive weed in the riparian habitats of the Rio Grande Basin. A biological control program using specialist insects from the native range in Mediterranean Europe, including the arundo scale, Rhizaspidiotus donacis has been implemented. The arundo scale is a sessile insect that spends most of its life cycle affixed to its host plant, thus creating challenges for its rearing and redistribution to field sites. A horticultural technique was developed which allowed for rearing of the scale on small, potted A. donax microplants, which could later be transplanted to field sites. Female scale reach maturity on the microplants and produce mobile crawler scale, which move to adjacent uninfested A. donax plants. Arundo scale were established at 48 sites on the Rio Grande using microplants. This horticultural technique allows for movement of the arundo scale at any stage of its life cycle to field sites to conduct biological control programs for A. donax where it is invasive.

PhytoFrontiers™, 2022

Trichoderma spp. are commonly used as bioremediation agents, as biological controls, and for maki... more Trichoderma spp. are commonly used as bioremediation agents, as biological controls, and for making biofuels. Herein, a Trichoderma harzianum strain PAR3 was isolated from grapevine roots in central California, U.S.A. As part of a larger whole genome sequencing effort, the mitochondrial genome (mitogenome) sequence was obtained for the PAR3 strain. The mitogenome is 27,631 bp, containing genes of 14 core mitochondrial proteins, 25 transfer RNAs, and two ribosomal RNAs, with a GC% content of 27.55%. A BLAST search using the PAR3 mitogenome as a query against the GenBank sequence database showed that the mitogenome MUT3171 (29,791 bp) of Trichoderma lixii was the most similar (query coverage = 99%; percentage identity = 100%) with two major deletions, 1,339 bp and 821 bp. The PAR3 mitogenome sequence will provide a useful reference for comparing different Trichoderma strains from the United States and around the world. Fungal strain PAR3 was isolated from roots of a Scarlet Royal grapevine on Freedom rootstock growing in a vineyard in Parlier, CA, U.S.A., in the summer of 2020. Morphological identification of PAR3 suggested it was T. harzianum Rifai (which has the teleomorph Hypocrea lixii Pat. according to Chaverri and Samuels 2002), following a dichotomous key by Chaverri and Samuels (2003) and Chaverri et al. (2016). As a strain of T. harzianum, PAR3 exhibits putative activity against various fungal pathogens, including those that could cause grapevine trunk diseases such as Diplodia seriata, Eutypa lata, and Neofusicoccum parvum. All of these pathogens cause cankers that develop over time, ultimately resulting in the need to replant vineyards every 10 to 12 years where prevalent (Baumgartner et al. 2019; Kaplan et al. 2016). Thus, there exists a need to further characterize PAR3. Mitochondrial genomes are important in species identification and marker development due to small sizes, high copy numbers, and presence of both conserved and variable regions (Medina et al. 2020). Previously, a variety of Trichoderma spp. have had mitochondrial genomes reported and analyzed (Kwak 2020). However, only a handful of species, consistently mostly of industry-useful isolates, have been analyzed by Kwak (2020). Therefore, the PAR3 mitochondrial genome as a resource is an important addition to expand our knowledge of Trichoderma species. Total genomic DNA was extracted using a Macherey-Nagel (Bethlehem, PA, U.S.A.

Journal of Animal Science, 2019

Bovine babesiosis, a highly fatal tick-borne disease of cattle, was eliminated from the United St... more Bovine babesiosis, a highly fatal tick-borne disease of cattle, was eliminated from the United States in the last century through tick eradication programs against 2 species of cattle fever ticks. The threat to the U.S. cattle industry continues through tick introductions from Mexico. The standard method of detecting Cattle Fever Ticks [Rhipicephalus (B.) annulatus and R. (B.) microplus] in the state-federal tick eradication program is physical examination of restrained cattle to find attached ticks. New methods of detecting tick-infested cattle could improve reliability and reduce animal stress. The objective of this study was to determine whether changes in fecal chemistry induced by tick infestation was detectable using near-infrared reflectance spectroscopy (NIRS). Fecal samples were collected daily from 6 stanchioned Bos taurus yearling heifers (initial mean weight 163.3 kg +/- 4.7 kg) at the USDA Cattle Fever Tick Research Laboratory, Edinburg, TX, before, during, and after an...

International Journal for Parasitology: Drugs and Drug Resistance, 2019

The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, is the most economically imp... more The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, is the most economically important ectoparasite of cattle worldwide. A limitation for sustainable control and eradication is the emergence of acaricide resistance among tick populations. Molecular diagnostic tools offer the opportunity to detect resistance rapidly, which can be complemented with confirmatory bioassays with larvae and adult ticks that are more resource and time consuming to generate. Synthetic pyrethroid resistance is one of the most prevalent and well-studied forms of resistance in arthropods, being linked with target site alterations in the sodium ion channel gene. Here, we report research on a novel molecular method to detect mutations in the para-sodium channel gene of R. microplus associated with acaricide resistance that is based on quantitative PCR high-resolution melt (HRM) analysis. Genomic DNA fragments of domains II and III of the para-sodium channel gene were amplified by real-time PCR in the presence of EVA ® Green dye to test resistant and susceptible reference ticks from the U.S., Brazil, and Mexico. Larval packet tests with discriminating doses and a modified lethal time analysis were performed to confirm resistance to permethrin, cypermethrin, deltamethrin, and flumethrin in laboratory strains. Tick specimens collected from cattle that were inspected at the United States Port-of-Entry at the Texas-Mexico border were also genotyped. Previously described mutations associated with pyrethroid resistance (T170C, C190A, G184C, and T2134A) were successfully detected by qPCR-HRM in different genotypes and confirmed by sequencing. A novel non-synonymous SNP located at domain III (C2136A) and the G215T mutation in domain II, previously described only in Asian R. microplus and R. australis, were also detected with the HRM and confirmed by sequencing. This technique could be adapted for high-throughput screening, detection, and discovery of allele-specific mutations in cattle tick outbreak populations to inform eradication strategies in the USA. This knowledge could also be applied to integrated control programs in other parts of the world where R. microplus is endemic and where similar SNPs have been identified associated with pyrethroid resistance. This study highlights the existence of several mutations in the para-sodium channel gene in different combinations in field populations of R. microplus from Mexico.

Ticks and Tick-borne Diseases, 2017

Ticks and tick-borne diseases are a major constraint for a sustainable cattle industry in the tro... more Ticks and tick-borne diseases are a major constraint for a sustainable cattle industry in the tropical and subtropical regions of the world. The development of resistance to most of the commonly used acaricides has led to an assessment of herbal products for acaricidal activity as an eco-friendly tick control alternative. A botanical product, Essentria ® IC-3 insect concentrate containing rosemary oil (10%), geraniol (5%) and peppermint oil (2%), acts on target pests by blocking octopamine. Essentria ® IC-3 and its active components were evaluated for larvicidal activity against several susceptible and acaricide-resistant strains of the cattle fever tick, Rhipicephalus (Boophilus) microplus Canestrini by Larval Packet test using 14-21 d old unfed larvae. The efficacy was assessed by measuring percent larval mortality and estimating lethal concentrations at 50% (LC 50) and 95% (LC 95) with 95% confidence limits (CL) using probit analysis. The LC 50 and LC 95 (95% CL) values for Essentria ® IC-3 against the susceptible strain were estimated as 0.647% (0.59-0.69) and 1.033% (0.94-1.19), respectively, whereas, LC 50 and LC 95 values for other strains were variable, ranging from 0.597-1.674% and 0.927-2.236%, respectively. Among the various active ingredients, the larvicidal property of Essentria ® IC-3 seem to be attributable mainly to geraniol and the LC 50 and LC 95 (95% CL) values for geraniol against the susceptible Deutch strain were estimated as 0.656% (0.61-0.69) and 1.114% (1.03-1.25), respectively. The comparison of LC 50 and LC 95 values of acaricide-resistant strains showed susceptibility comparable to Deutch against geraniol except for the Las Palmas strain. We report a low level of resistance in some of the acaricide-resistant strains against the herbal acaricide in the cattle tick for the first time, possibly due to cross-resistance to chemical acaricides.

The American Journal of Tropical Medicine and Hygiene, 1997

Several species of Culicoides biting midges are important pests and vectors of pathogens affectin... more Several species of Culicoides biting midges are important pests and vectors of pathogens affecting humans and other animals. Bluetongue is the most economically important arthropod-borne animal disease in the United States. Culicoides variipennis is the primary North American vector of the bluetongue viruses. A reddish halo surrounding a petechial hemorrhage was noticed at the site of C. variipennis blood feeding in previously unexposed sheep and rabbits. Salivary gland extracts of nonblood-fed C. variipennis injected intradermally into sheep and rabbits induced cutaneous vasodilation in the form of erythema. A local, dose-dependent erythema, without edema or pruritus, was noted 30 min after injection. Erythema was inapparent with salivary gland extracts obtained after blood feeding. This observation suggested that the vasodilatory activity was inoculated into the host skin at the feeding site. The vasodilatory activity was insoluble in ethanol and destroyed by trypsin or chymotrypsin, which indicated that vasodilation was due to a protein. The association of cutaneous vasodilation with a salivary protein was corroborated by reversed-phase, high-performance liquid chromatography (HPLC). Fractionation of salivary gland extracts by molecular sieving HPLC resulted in maximal vasodilatory activity that coeluted with a protein having a relative molecular weight (MWr) of 22.45 kD. The C. variipennis vasodilator appears to be biologically active at the nanogram level. This vasodilator likely assists C. variipennis during feeding by increasing blood flow from host superficial blood vessels surrounding the bite site. The identification of a salivary vasodilator in C. variipennis may have implications for the transmission of Culicoides-borne pathogens and in the development of dermatitis resulting from the sensitization of humans and animals to Culicoides salivary antigens.

Archives of Insect Biochemistry and Physiology, 2016

Emerging and re‐emerging tick‐borne diseases threaten public health and the wellbeing of domestic... more Emerging and re‐emerging tick‐borne diseases threaten public health and the wellbeing of domestic animals and wildlife globally. The adoption of an evolutionary ecology framework aimed to diminish the impact of tick‐borne diseases needs to be part of strategies to protect human and animal populations. We present a review of current knowledge on the adaptation of ticks to their environment, and the impact that global change could have on their geographic distribution in North America. Environmental pressures will affect tick population genetics by selecting genotypes able to withstand new and changing environments and by altering the connectivity and isolation of several tick populations. Research in these areas is particularly lacking in the southern United States and most of Mexico with knowledge gaps on the ecology of these diseases, including a void in the identity of reservoir hosts for several tick‐borne pathogens. Additionally, the way in which anthropogenic changes to landsca...

Parasites & Vectors, 2010

Background Tick parasitism is a major impediment for cattle production in many parts of the world... more Background Tick parasitism is a major impediment for cattle production in many parts of the world. The southern cattle tick, Rhipicephalus (Boophilus) microplus, is an obligate hematophagous parasite of domestic and wild animals that serves as vector of infectious agents lethal to cattle. Tick saliva contains molecules evolved to modulate host innate and adaptive immune responses which facilitates blood feeding and pathogen transmission. Tick feeding promotes CD4 T cell polarization to a Th2 profile usually accompanied by down-regulation of Th1 cytokines through as yet undefined mechanisms. Co-stimulatory molecules on antigen presenting cells are central to development of T cell responses including Th1 and Th2 responses. Tick induced changes to antigen presenting cell signal transduction pathways are largely unknown. Here we document the ability of R. microplus salivary gland extracts (SGE) to effect differential CD86 expression. Results We examined changes in co-stimulatory molecul...

Revista Mexicana de Ciencias Pecuarias, 2012

We review recent progress for control of Rhipicephalus (Boophilus) microplus and R. (B.) annulatu... more We review recent progress for control of Rhipicephalus (Boophilus) microplus and R. (B.) annulatus. Outbreak infestations in the U.S. have reached alarming levels, due to increased populations of deer and other ungulates serving as alternative hosts. GIS mapping of infestations and deer habitat aids in utilizing methods and equipment designed for acaricide treatment of wild ungulates. Investigations include deer immunology, tick molecular genetics, acaricide resistance, and host-parasite interactions with deer or cattle, ticks, and pathogens. Acaricide resistance is widespread in Mexico and U.S. dipping vats depend on organophosphate (OP) inhibition of acetylcholinesterase (AChE). Three cDNAs putatively encoding acetylcholinesterases (AChE, E.C. 3.1.1.7) in R. (B.) microplus were expressed in the baculovirus system and exhibited Km values for acetylthiocholine of approx. 5, 50, or 90 µM, for rBmAChE1, rBmAChE2, and rBmAChE3, respectively. The rBmAChEs exhibited substrate preference ...

G3 (Bethesda, Md.), Jan 30, 2018

Haematobia irritans, commonly known as the horn fly, is a globally distributed blood-feeding pest... more Haematobia irritans, commonly known as the horn fly, is a globally distributed blood-feeding pest of cattle that is responsible for significant economic losses to cattle producers. Chemical insecticides are the primary means for controlling this pest but problems with insecticide resistance have become common in the horn fly. To provide a foundation for identification of genomic loci for insecticide resistance and for discovery of new control technology, we report the sequencing, assembly, and annotation of the horn fly genome. The assembled genome is 1.14 Gb, comprising 76,616 scaffolds with N50 scaffold length of 23 Kb. Using RNA-Seq data, we have predicted 34,413 gene models of which 19,185 have been assigned functional annotations. Comparative genomics analysis with the Dipteran flies Musca domestica L., Drosophila melanogaster, and Lucilia cuprina, show that the horn fly is most closely related to M. domestica, sharing 8,748 orthologous clusters followed by D. melanogaster and L. cuprina, sharing 7,582 and 7,490 orthologous clusters respectively. We also identified a gene locus for the sodium channel protein in which mutations have been previously reported that confers target site resistance to the most common class of pesticides used in fly control. Additionally, we identified 276 genomic loci encoding members of metabolic enzyme gene families such as cytochrome P450s, esterases and glutathione S-transferases, and several genes orthologous to sex determination pathway genes in other Dipteran species. KEYWORDS horn fly sex determination genes pesticide resistance metabolic resistance The horn fly, Haematobia irritans, is one of the most widespread and economically important ectoparasites of cattle in the world. The fly is found in Europe, Africa, Asia, and the Americas, imparting significant discomfort to cattle and economic impact to cattle producers. The entire life cycle of the horn fly is centered upon cattle, as eggs are laid in fresh manure wherein larvae and pupae develop, after which the adult fly emerges and immediately begins feeding upon a bovine host. The adult fly is hematophageous, feeding 20-40 times per day, primarily upon cattle. Economic impact of the horn fly has been estimated at US $2.5 billion annual losses in Brazil alone (Grisi et al. 2014). Control of this pest relies upon the use of insecticides, but resistance to the most commonly available products in the pyrethroid and organophosphate classes is a major problem leading to control failures (Guerrero and Barros 2006; Jamroz et al. 1998; Barros et al. 2001). The effects of climate change and global warming have been predicted to increase the fly's economic impact upon the U. S. cattle and the cattle industry, particularly in the Northern states (Schmidtmann and Miller 1989).

Molecular ecology, Jan 9, 2017

Ecological specialization to restricted diet-niches is driven by obligate, and often maternally i... more Ecological specialization to restricted diet-niches is driven by obligate, and often maternally inherited, symbionts in many arthropod lineages. These heritable symbionts typically form evolutionarily stable associations with arthropods that can last for millions of years. Ticks were recently found to harbor such an obligate symbiont, Coxiella-LE, that synthesizes B vitamins and cofactors not obtained in sufficient quantities from blood diet. In this study, the examination of 81 tick species show that some Coxiella-LE symbioses are evolutionarily stable with an ancient acquisition followed by co-diversification as observed in ticks belonging to the Rhipicephalus genus. However, many other Coxiella-LE symbioses are characterized by low evolutionary stability with frequent host shifts and extinction events. Further examination revealed the presence of nine other genera of maternally inherited bacteria in ticks. Although these nine symbionts were primarily thought to be facultative, th...

Data in brief, 2016

The New World Screwworm (NWS), Cochliomyia hominivorax, is a pest insect that is endemic to subtr... more The New World Screwworm (NWS), Cochliomyia hominivorax, is a pest insect that is endemic to subtropical and tropical regions of the Western Hemisphere. The female lays eggs in open wounds or orifices of warm-blooded animals. Upon hatching, the resulting larvae feed upon the host׳s living tissues, which can become infected and death can occur. The sterile insect technique was developed to eradicate this pest from North America and new female conditional-lethal strains that generate only male individuals are being developed for use in the eradication program. To facilitate the identification of useful transcripts and gene promoters for these new strains, we used an Illumina Hi-Seq protocol to sequence the testes transcriptome of NWS. We report the assembly of 4149 transcripts (≥200 nt) from testes dissected from NWS males obtained from the J06 strain used in the screwworm production plant in Pacora, Panama. Functional annotation resulted in 2060, 2031, 558, and 325 transcripts with as...

Though eradicated from the US for the past half century, reemergence of populations of southern c... more Though eradicated from the US for the past half century, reemergence of populations of southern cattle tick, Rhipicephalus (Boophilus) microplus, and cattle-fever tick, R. (B). annulatus which transmit the blood parasites that cause lethal cattle disease, is of major concern. Given that the key management area of Rhipicephalus ticks in south Texas overlap with the densest infestations of invasive giant reed (Arundo donax L.) in the US, we determine whether giant reed invasions are positively or negatively associated with survival of ticks. We look at tick survivorship and reproduction in three common riparian habitats: native forests, arundo stands, and pastures of exotic buffelgrass. Engorged females in the three habitats were likely to lay eggs and larger masses in arundo and native forests when compared to ticks in buffelgrass where daily temperatures were higher. Average high temperatures predicted the proportion of egg laying ticks (b=-15.81, t(8)=25.74, p

The polar cuticular lipids of the Old World sand fly, Phlebotomus papatasi, were analyzed by high... more The polar cuticular lipids of the Old World sand fly, Phlebotomus papatasi, were analyzed by high resolution mass spectrometry. Blood-fed females, non-blood-fed females and males were separately analyzed and compared. The major polar cuticular lipids were found to be long-chain diols and fatty acids. Relatively high levels of diacylglycerols were found in blood-fed females and in males. A wide variety of lipids were found at low levels, including esters, sterols, monoacylglycerols, and hydroxy fatty acids. Blood-fed females had several lyso lipids and N-acyl amino acids that were not found on unfed females or males. These substances may be surfactants used in blood-feeding. Heneicosanoic acid was found on females at more than twice the level of males, suggesting it could be a component of a previously-described female aggregation pheromone. Four substances were identified on males at two-fold higher levels than on females: tetradienoic acid, methoxyhexadecasphinganine, butyl octadec...

Revista Brasileira de Parasitologia Veterinária, 2011

This study was conducted to obtain an epidemiological view of acaricide resistance in populations... more This study was conducted to obtain an epidemiological view of acaricide resistance in populations of Rhipicephalus (Boophilus) microplus in the State of Mato Grosso do Sul. Twenty-four tick samples were collected from municipalities in the State where farmers had reported concerns about resistance to or failure of tick control. These ticks were subjected to in vitro resistance detection assays using the adult immersion test (AIT). The efficacy of alpha-cypermethrin, cypermethrin and amitraz treatments on samples collected throughout the State was generally poor. AIT showed efficacy > 90% from the use of DDVP + chlorfenvinphos) (20 out of 21 municipalities), dichlorvos + cypermethrin (10 out of 16 municipalities) and cypermethrin + citronella + chlorpyrifos + piperonyl butoxide (20 out of 21 municipalities). PCR assays were used to detect the presence of pyrethroid resistance-associated sodium channel gene mutation. Larvae from three different populations that had previously been ...

Veterinary Parasitology, 2013

Five strains of Rhipicephalus (Boophilus) microplus collected from Tamaulipas Mexico were tested ... more Five strains of Rhipicephalus (Boophilus) microplus collected from Tamaulipas Mexico were tested for resistance against several classes of acaricides commonly used. All were resistant to fipronil. Four of five were co-resistant to permethrin and coumaphos in addition to being resistant to fipronil. One strain, El Zamora was found multi-resistant to permethrin, coumaphos, fipronil, and amitraz. Selection with fipronil for 3 generations produced a resistance ratio of 8.3 and 9.4 at the LC 50 and the LC 99 estimates, respectively. Permethrin resistance in El Zamora was possibly linked to elevated esterase (CZEST9) and could be a contributing factor of resistance to fipronil. The implications of resistance for the control of the southern cattle tick in the future are discussed.

Parasites & Vectors, 2010

Background Babesia are emerging health threats to humans and animals in the United States. A coll... more Background Babesia are emerging health threats to humans and animals in the United States. A collaborative effort of multiple disciplines to attain optimal health for people, animals and our environment, otherwise known as the One Health concept, was taken during a research workshop held in April 2009 to identify gaps in scientific knowledge regarding babesioses. The impetus for this analysis was the increased risk for outbreaks of bovine babesiosis, also known as Texas cattle fever, associated with the re-infestation of the U.S. by cattle fever ticks. Results The involvement of wildlife in the ecology of cattle fever ticks jeopardizes the ability of state and federal agencies to keep the national herd free of Texas cattle fever. Similarly, there has been a progressive increase in the number of cases of human babesiosis over the past 25 years due to an increase in the white-tailed deer population. Human babesiosis due to cattle-associated Babesia divergens and Babesia divergens-like...

Journal of Medical Entomology, 2011

Frontiers in Plant Science, Dec 15, 2022

Background: Huanglongbing (HLB, yellow shoot disease) is a highly destructive citrus disease asso... more Background: Huanglongbing (HLB, yellow shoot disease) is a highly destructive citrus disease associated with a nonculturable bacterium, "Candidatus Liberibacter asiaticus" (CLas), which is transmitted by Asian citrus psyllid (ACP, Diaphorina citri). In Mexico, HLB was first reported in Tizimin, Yucatań, in 2009 and is now endemic in 351 municipalities of 25 states. Understanding the population diversity of CLas is critical for HLB management. Current CLas diversity research is exclusively based on analysis of the bacterial genome, which composed two regions, chromosome (> 1,000 genes) and prophage (about 40 genes). Methods and results: In this study, 40 CLas-infected ACP samples from 20 states in Mexico were collected. CLas was detected and confirmed by PCR assays. A prophage gene(terL)-based typing system (TTS) divided the Mexican CLas strains into two groups: Term-G including four strains from Yucatań and Chiapas, as well as strain psy62 from Florida, USA, and Term-A included all other 36 Mexican strains, as well as strain AHCA1 from California, USA. CLas diversity was further evaluated to include all chromosomal and prophage genes assisted by using machine learning (ML) tools to resolve multidimensional data handling issues. A Term-G strain (YTMX) and a Term-A strain (BCSMX) were sequenced and analyzed. The two Mexican genome sequences along with the CLas genome sequences available in GenBank were studied. An unsupervised ML was implemented through principal component analysis (PCA) on average nucleotide identities (ANIs) of CLas whole genome sequences; And a supervised ML was implemented through sparse partial least squares Frontiers in Plant Science frontiersin.org 01

Subtropical Agriculture and Environments, 2016

Arundo donax, giant reed is an invasive weed in the riparian habitats of the Rio Grande Basin. A ... more Arundo donax, giant reed is an invasive weed in the riparian habitats of the Rio Grande Basin. A biological control program using specialist insects from the native range in Mediterranean Europe, including the arundo scale, Rhizaspidiotus donacis has been implemented. The arundo scale is a sessile insect that spends most of its life cycle affixed to its host plant, thus creating challenges for its rearing and redistribution to field sites. A horticultural technique was developed which allowed for rearing of the scale on small, potted A. donax microplants, which could later be transplanted to field sites. Female scale reach maturity on the microplants and produce mobile crawler scale, which move to adjacent uninfested A. donax plants. Arundo scale were established at 48 sites on the Rio Grande using microplants. This horticultural technique allows for movement of the arundo scale at any stage of its life cycle to field sites to conduct biological control programs for A. donax where it is invasive.

PhytoFrontiers™, 2022

Trichoderma spp. are commonly used as bioremediation agents, as biological controls, and for maki... more Trichoderma spp. are commonly used as bioremediation agents, as biological controls, and for making biofuels. Herein, a Trichoderma harzianum strain PAR3 was isolated from grapevine roots in central California, U.S.A. As part of a larger whole genome sequencing effort, the mitochondrial genome (mitogenome) sequence was obtained for the PAR3 strain. The mitogenome is 27,631 bp, containing genes of 14 core mitochondrial proteins, 25 transfer RNAs, and two ribosomal RNAs, with a GC% content of 27.55%. A BLAST search using the PAR3 mitogenome as a query against the GenBank sequence database showed that the mitogenome MUT3171 (29,791 bp) of Trichoderma lixii was the most similar (query coverage = 99%; percentage identity = 100%) with two major deletions, 1,339 bp and 821 bp. The PAR3 mitogenome sequence will provide a useful reference for comparing different Trichoderma strains from the United States and around the world. Fungal strain PAR3 was isolated from roots of a Scarlet Royal grapevine on Freedom rootstock growing in a vineyard in Parlier, CA, U.S.A., in the summer of 2020. Morphological identification of PAR3 suggested it was T. harzianum Rifai (which has the teleomorph Hypocrea lixii Pat. according to Chaverri and Samuels 2002), following a dichotomous key by Chaverri and Samuels (2003) and Chaverri et al. (2016). As a strain of T. harzianum, PAR3 exhibits putative activity against various fungal pathogens, including those that could cause grapevine trunk diseases such as Diplodia seriata, Eutypa lata, and Neofusicoccum parvum. All of these pathogens cause cankers that develop over time, ultimately resulting in the need to replant vineyards every 10 to 12 years where prevalent (Baumgartner et al. 2019; Kaplan et al. 2016). Thus, there exists a need to further characterize PAR3. Mitochondrial genomes are important in species identification and marker development due to small sizes, high copy numbers, and presence of both conserved and variable regions (Medina et al. 2020). Previously, a variety of Trichoderma spp. have had mitochondrial genomes reported and analyzed (Kwak 2020). However, only a handful of species, consistently mostly of industry-useful isolates, have been analyzed by Kwak (2020). Therefore, the PAR3 mitochondrial genome as a resource is an important addition to expand our knowledge of Trichoderma species. Total genomic DNA was extracted using a Macherey-Nagel (Bethlehem, PA, U.S.A.

Journal of Animal Science, 2019

Bovine babesiosis, a highly fatal tick-borne disease of cattle, was eliminated from the United St... more Bovine babesiosis, a highly fatal tick-borne disease of cattle, was eliminated from the United States in the last century through tick eradication programs against 2 species of cattle fever ticks. The threat to the U.S. cattle industry continues through tick introductions from Mexico. The standard method of detecting Cattle Fever Ticks [Rhipicephalus (B.) annulatus and R. (B.) microplus] in the state-federal tick eradication program is physical examination of restrained cattle to find attached ticks. New methods of detecting tick-infested cattle could improve reliability and reduce animal stress. The objective of this study was to determine whether changes in fecal chemistry induced by tick infestation was detectable using near-infrared reflectance spectroscopy (NIRS). Fecal samples were collected daily from 6 stanchioned Bos taurus yearling heifers (initial mean weight 163.3 kg +/- 4.7 kg) at the USDA Cattle Fever Tick Research Laboratory, Edinburg, TX, before, during, and after an...

International Journal for Parasitology: Drugs and Drug Resistance, 2019

The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, is the most economically imp... more The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, is the most economically important ectoparasite of cattle worldwide. A limitation for sustainable control and eradication is the emergence of acaricide resistance among tick populations. Molecular diagnostic tools offer the opportunity to detect resistance rapidly, which can be complemented with confirmatory bioassays with larvae and adult ticks that are more resource and time consuming to generate. Synthetic pyrethroid resistance is one of the most prevalent and well-studied forms of resistance in arthropods, being linked with target site alterations in the sodium ion channel gene. Here, we report research on a novel molecular method to detect mutations in the para-sodium channel gene of R. microplus associated with acaricide resistance that is based on quantitative PCR high-resolution melt (HRM) analysis. Genomic DNA fragments of domains II and III of the para-sodium channel gene were amplified by real-time PCR in the presence of EVA ® Green dye to test resistant and susceptible reference ticks from the U.S., Brazil, and Mexico. Larval packet tests with discriminating doses and a modified lethal time analysis were performed to confirm resistance to permethrin, cypermethrin, deltamethrin, and flumethrin in laboratory strains. Tick specimens collected from cattle that were inspected at the United States Port-of-Entry at the Texas-Mexico border were also genotyped. Previously described mutations associated with pyrethroid resistance (T170C, C190A, G184C, and T2134A) were successfully detected by qPCR-HRM in different genotypes and confirmed by sequencing. A novel non-synonymous SNP located at domain III (C2136A) and the G215T mutation in domain II, previously described only in Asian R. microplus and R. australis, were also detected with the HRM and confirmed by sequencing. This technique could be adapted for high-throughput screening, detection, and discovery of allele-specific mutations in cattle tick outbreak populations to inform eradication strategies in the USA. This knowledge could also be applied to integrated control programs in other parts of the world where R. microplus is endemic and where similar SNPs have been identified associated with pyrethroid resistance. This study highlights the existence of several mutations in the para-sodium channel gene in different combinations in field populations of R. microplus from Mexico.

Ticks and Tick-borne Diseases, 2017

Ticks and tick-borne diseases are a major constraint for a sustainable cattle industry in the tro... more Ticks and tick-borne diseases are a major constraint for a sustainable cattle industry in the tropical and subtropical regions of the world. The development of resistance to most of the commonly used acaricides has led to an assessment of herbal products for acaricidal activity as an eco-friendly tick control alternative. A botanical product, Essentria ® IC-3 insect concentrate containing rosemary oil (10%), geraniol (5%) and peppermint oil (2%), acts on target pests by blocking octopamine. Essentria ® IC-3 and its active components were evaluated for larvicidal activity against several susceptible and acaricide-resistant strains of the cattle fever tick, Rhipicephalus (Boophilus) microplus Canestrini by Larval Packet test using 14-21 d old unfed larvae. The efficacy was assessed by measuring percent larval mortality and estimating lethal concentrations at 50% (LC 50) and 95% (LC 95) with 95% confidence limits (CL) using probit analysis. The LC 50 and LC 95 (95% CL) values for Essentria ® IC-3 against the susceptible strain were estimated as 0.647% (0.59-0.69) and 1.033% (0.94-1.19), respectively, whereas, LC 50 and LC 95 values for other strains were variable, ranging from 0.597-1.674% and 0.927-2.236%, respectively. Among the various active ingredients, the larvicidal property of Essentria ® IC-3 seem to be attributable mainly to geraniol and the LC 50 and LC 95 (95% CL) values for geraniol against the susceptible Deutch strain were estimated as 0.656% (0.61-0.69) and 1.114% (1.03-1.25), respectively. The comparison of LC 50 and LC 95 values of acaricide-resistant strains showed susceptibility comparable to Deutch against geraniol except for the Las Palmas strain. We report a low level of resistance in some of the acaricide-resistant strains against the herbal acaricide in the cattle tick for the first time, possibly due to cross-resistance to chemical acaricides.

The American Journal of Tropical Medicine and Hygiene, 1997

Several species of Culicoides biting midges are important pests and vectors of pathogens affectin... more Several species of Culicoides biting midges are important pests and vectors of pathogens affecting humans and other animals. Bluetongue is the most economically important arthropod-borne animal disease in the United States. Culicoides variipennis is the primary North American vector of the bluetongue viruses. A reddish halo surrounding a petechial hemorrhage was noticed at the site of C. variipennis blood feeding in previously unexposed sheep and rabbits. Salivary gland extracts of nonblood-fed C. variipennis injected intradermally into sheep and rabbits induced cutaneous vasodilation in the form of erythema. A local, dose-dependent erythema, without edema or pruritus, was noted 30 min after injection. Erythema was inapparent with salivary gland extracts obtained after blood feeding. This observation suggested that the vasodilatory activity was inoculated into the host skin at the feeding site. The vasodilatory activity was insoluble in ethanol and destroyed by trypsin or chymotrypsin, which indicated that vasodilation was due to a protein. The association of cutaneous vasodilation with a salivary protein was corroborated by reversed-phase, high-performance liquid chromatography (HPLC). Fractionation of salivary gland extracts by molecular sieving HPLC resulted in maximal vasodilatory activity that coeluted with a protein having a relative molecular weight (MWr) of 22.45 kD. The C. variipennis vasodilator appears to be biologically active at the nanogram level. This vasodilator likely assists C. variipennis during feeding by increasing blood flow from host superficial blood vessels surrounding the bite site. The identification of a salivary vasodilator in C. variipennis may have implications for the transmission of Culicoides-borne pathogens and in the development of dermatitis resulting from the sensitization of humans and animals to Culicoides salivary antigens.