Vertebrate-Aedes aegypti and Culex quinquefasciatus (Diptera)-arbovirus transmission networks: Non-human feeding revealed by meta-barcoding and next-generation sequencing

BackgroundAedes aegypti mosquito-borne viruses including Zika (ZIKV), dengue (DENV), yellow fever (YFV), and chikungunya (CHIKV) have emerged and re-emerged globally, resulting in an elevated burden of human disease. Aedes aegypti is found worldwide in tropical, sub-tropical, and temperate areas. The characterization of mosquito blood meals is essential to understand the transmission dynamics of mosquito-vectored pathogens.Methodology/principal findingsHere, we report Ae. aegypti and Culex quinquefasciatus host feeding patterns and arbovirus transmission in Northern Mexico using a metabarcoding-like approach with next-generation deep sequencing technology. A total of 145 Ae. aegypti yielded a blood meal analysis result with 107 (73.8%) for a single vertebrate species and 38 (26.2%) for two or more. Among the single host blood meals for Ae. aegypti, 28.0% were from humans, 54.2% from dogs, 16.8% from cats, and 1.0% from tortoises. Among those with more than one species present, 65.9% were from humans and dogs. For Cx. quinquefasciatus, 388 individuals yielded information with 326 (84%) being from a single host and 63 (16.2%) being from two or more hosts. Of the single species blood meals, 77.9% were from dogs, 6.1% from chickens, 3.1% from house sparrows, 2.4% from humans, while the remaining 10.5% derived from other 12 host species. Among those which had fed on more than one species, 11% were from dogs and humans, and 89% of other host species combinations. Forage ratio analysis revealed dog as the most over-utilized host by Ae. aegypti (= 4.3) and Cx. quinquefasciatus (= 5.6) and the human blood index at 39% and 4%, respectively. A total of 2,941 host-seeking female Ae. aegypti and 3,536 Cx. quinquefasciatus mosquitoes were collected in the surveyed area. Of these, 118 Ae. aegypti pools and 37 Cx. quinquefasciatus pools were screened for seven arboviruses (ZIKV, DENV 1–4, CHIKV, and West Nile virus (WNV)) using qRT-PCR and none were positive (point prevalence = 0%). The 95%-exact upper limit confidence interval was 0.07% and 0.17% for Ae. aegypti and Cx. quinquefasciatus, respectivelyConclusions/significanceThe low human blood feeding rate in Ae. aegypti, high rate of feeding on mammals by Cx. quinquefasciatus, and the potential risk to transmission dynamics of arboviruses in highly urbanized areas of Northern Mexico is discussed.     

Genetic diversity in oak populations under intensive management for fuelwood in the Sierra de Zongolica,Mexico

Firewood and charcoal are used on a daily basis both in rural areas and in cities. This type of energy is produced by one of the most ancient traditional methods, known as coppice, which harvest tree sprouts. There is controversy about its effects on forests: it preserves populations and tree cover of species used, but reduces density, inhibits sexual reproduction and generates genetic erosion. We inquired if it was possible to identify a loss of genetic diversity in oak populations traditionally used for charcoal by the Zongolica Nahuas in Veracruz state, Mexico. We studied populations of Quercus laurina, Quercus calophylla and Quercus rugosa in three different altitudes. Molecular analysis with eight nuclear codominant microsatellites was performed to determine the diversity, structure and gene flow of these species. Results for Q. laurina were Na = 8.458, I = 1.766, Ho = 0.679, polymorphism = 100%, Fis = 0.079, with intraindividual variation of 81.55%. For Q. calophylla: Na = 7.250, I = 1.563, Ho = 0.646, polymorphism = 91.67%, Fis = 0.083, with intraindividual variation of 83.80%. For Q. rugosa: Na = 6.958, I = 1.510, Ho = 0.574, polymorphism = 91.67%, Fis = 0.204, with intraindividual variation of 81.99%; this species shows signals of an early genetic isolation process. Our findings indicate that Quercus genetic diversity for the three species is high and comparable with oak species in Mexico and worldwide. We conclude that at the present, coppice is preserving a historical diversity in adult trees kept alive through sprouting. Nonetheless, problems with coppice systems elsewhere, unregulated harvesting and expansion of pine plantation in the region suggest that further studies, hand in hand with a landscape management approach that improve charcoal and firewood production, may be valuable for Sierra de Zongolica genetic biodiversity conservation.     

Cosolute modulation of protein oligomerization reactions in the homeostatic timescale

Protein oligomerization processes are widespread and of crucial importance to understand degenerative diseases and healthy regulatory pathways. One particular case is the homo-oligomerization of folded domains involving domain swapping, often found as a part of the protein homeostasis in the crowded cytosol, composed of a complex mixture of cosolutes. Here, we have investigated the effect of a plethora of cosolutes of very diverse nature on the kinetics of a protein dimerization by domain swapping. In the absence of cosolutes, our system exhibits slow interconversion rates, with the reaction reaching the equilibrium within the average protein homeostasis timescale (24–48 h). In the presence of crowders, though, the oligomerization reaction in the same time frame will, depending on the protein's initial oligomeric state, either reach a pure equilibrium state or get kinetically trapped into an apparent equilibrium. Specifically, when the reaction is initiated from a large excess of dimer, it becomes unsensitive to the effect of cosolutes and reaches the same equilibrium populations as in the absence of cosolute. Conversely, when the reaction starts from a large excess of monomer, the reaction during the homeostatic timescale occurs under kinetic control, and it is exquisitely sensitive to the presence and nature of the cosolute. In this scenario (the most habitual case in intracellular oligomerization processes), the effect of cosolutes on the intermediate conformation and diffusion-mediated encounters will dictate how the cellular milieu affects the domain-swapping reaction.     

966. CLAVIJA DOMINGENSIS

Clavija domingensis Urb. & Ekman was one of the many Haitian endemics that were described based on collections made by the great Swedish botanist Leonard Ekman between 1924 and 1928. The species is Critically Endangered sensu IUCN (criteria c2a(i); D) and it is currently the focus of conservation initiatives in Jardin Botanique des Cayes (Haiti), Jardín Botánico Nacional Dr. Rafael M. Moscoso (Dominican Republic), and Fairchild Tropical Botanic Garden (U.S.A.). Now known from only six localities from southern Haiti, each locality only represents a single individual. The species is illustrated based on plants grown in Fairchild Tropical Botanic Garden.     

Head of the Class: John R. Wible’s Transformative Insights Into Mammalian Craniodental Anatomy

Journal of Mammalian Evolution -     

The role of anthocyanins as antidiabetic agents: from molecular mechanisms to in vivo and human studies

Journal of Physiology and Biochemistry - Diabetes mellitus is a chronic metabolic disease characterized by high blood glucose concentration. Nowadays, type 2 diabetes or insulin resistant diabetes...     

Spatial and seasonal distribution of the tuna catch on floating objects in the eastern pacific ocean during 1992–1993

An analysis of the catch associated with floating objects by the Mexican tuna purse‐seine fleet in the eastern Pacific Ocean during 1992–1993 was made to determine the spatial and seasonal distribution. The information used was generated by observers of the Programa Nacional de Aprovechamiento del Atun y Protección a los Delfines (PNAAPD). There was no clear seasonal and spatial distribution of floating objects examined in this study, however there were areas where floating objects were more common; the mouth of the Gulf of California, waters offshore Peru, and in oceanic waters. The largest catch of yellowfin tuna was offshore of Peru in winter. Two areas with largest (length) yellowfin tuna were the mouth of the Gulf of California and offshore Peru. For skipjack tuna, the largest catch was offshore Peru in winter, but the largest skipjack were caught between 120° and 130°W along 10°N in spring. The largest yellowfin tuna were captured by sets on bamboo, fish aggregating devices (FADs), planks and boards, and logs (trees or parts). The largest skipjack were captured by sets on dead whales, kelp paddies, planks and boards, and pallets and crates. Most of the sets were made during the early hours of the day but an important number of log sets were made in the early afternoon. For the period analyzed, floating objects were more frequent during fall and winter with the area offshore of Peru the most important.