scholarly journals Ticks (Acari: Ixodida) of the genus Haemaphysalis Koch, 1844 in Senegal: a review of host associations, chorology, and identification

Acarologia ◽  
2018 ◽  
Vol 58 (4) ◽  
pp. 928-945
Author(s):  
Massamba Sylla ◽  
Mady Ndiaye ◽  
Marc Souris ◽  
Jean-Paul Gonzalez

The Haemaphysalis genus (Acari, Ixodidae) in Senegal is reviewed. This embodies a summary of specimens collected from vertebrate hosts over three decades. 454 collections were performed over this period (408 from mammals and 46 from birds), representing a total of 5752 ticks in different developmental stages. Seven Haemaphysalis spp. were collected, identified, and inventoried including: H. (Kaiseriana) rugosa, H. (Ornithophysalis) hoodi, H. (Rhipistoma) houyi, as well as four other species belonging to the leachi group, namely H. (Rhipistoma) leachi, H. (Rh.) moreli, H. (Rh.) muhsamae and H. (Rh.) spinulosa. Vertebrate hosts of Haemaphysalis species were identified and listed in different ecological zones of Senegal. An identification key of the haemaphysalids of Senegal is proposed, which is also applicable to the haemaphysalid fauna of the Occidental sub-region of the Afrotropical zoogeographical region. The role of these species as potential vectors of zoonotic diseases in Senegal is also discussed.

Author(s):  
Massamba Sylla ◽  
Marc Souris ◽  
Jean-Paul Gonzalez

Ticks of the genus Rhipicephalus (Acari: Ixodidae) in Senegal were reviewed. The data presented originate from a tick collection maintained at IRD’s Laboratory of Medical Entomology since 1967 and continuously enriched with samples obtained from different vertebrate hosts captured during various projects conducted in Senegal from 1987 to 2007. Fifteen Rhipicephalus tick species were collected and characterized, resulting in 1127 referenced collections. Three species were of the Boophilus subgenus: Rhipicephalus (Bo.) annulatus, Rh. (Bo.) decoloratus and Rh. (Bo.) geigyi. The twelve others were Rh. boueti, Rh. cuspidatus, Rh. evertsi, Rh. guilhoni, Rh. lunulatus, Rh. muhsamae, Rh. sanguineus, Rh. senegalensis, Rh. sulcatus, Rh. tricuspis, Rh. turanicus and Rh. ziemanni. Although there were recent indications that Rh. turanicus should have been considered as part of the Rh. sanguineus s.l. complex, data regarding these two ticks were presented separately. The collection comprised 14,165 tick specimens at different developmental stages. Data concerning their host relationships as well as distribution and seasonal dynamics were also presented. Vertebrate hosts were identified and listed in the different ecological zones of Senegal. The role of the ticks as potential vectors of pathogens has been reviewed. Climate change, causing variations in rainfall and temperature, will impact tick distribution and dynamics. The situation supports the necessity of this inventory of tick populations for (re)emerging tick-borne diseases surveillance and monitoring.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fang Li ◽  
Zaichao Zheng ◽  
Hongyu Li ◽  
Rongrong Fu ◽  
Limei Xu ◽  
...  

AbstractDespite the central role of hemocytes in crustacean immunity, the process of hemocyte differentiation and maturation remains unclear. In some decapods, it has been proposed that the two main types of hemocytes, granular cells (GCs) and semigranular cells (SGCs), differentiate along separate lineages. However, our current findings challenge this model. By tracking newly produced hemocytes and transplanted cells, we demonstrate that almost all the circulating hemocytes of crayfish belong to the GC lineage. SGCs and GCs may represent hemocytes of different developmental stages rather than two types of fully differentiated cells. Hemocyte precursors produced by progenitor cells differentiate in the hematopoietic tissue (HPT) for 3 ~ 4 days. Immature hemocytes are released from HPT in the form of SGCs and take 1 ~ 3 months to mature in the circulation. GCs represent the terminal stage of development. They can survive for as long as 2 months. The changes in the expression pattern of marker genes during GC differentiation support our conclusions. Further analysis of hemocyte phagocytosis indicates the existence of functionally different subpopulations. These findings may reshape our understanding of crustacean hematopoiesis and may lead to reconsideration of the roles and relationship of circulating hemocytes.


Author(s):  
Raymond Berry

AbstractThe bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival. To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C. The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae. The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.


Author(s):  
Millissia Ben Maamar ◽  
Eric E Nilsson ◽  
Michael K Skinner

Abstract One of the most important developing cell types in any biological system is the gamete (sperm and egg). The transmission of phenotypes and optimally adapted physiology to subsequent generations is in large part controlled by gametogenesis. In contrast to genetics, the environment actively regulates epigenetics to impact the physiology and phenotype of cellular and biological systems. The integration of epigenetics and genetics is critical for all developmental biology systems at the cellular and organism level. The current review is focused on the role of epigenetics during gametogenesis for both the spermatogenesis system in the male and oogenesis system in the female. The developmental stages from the initial primordial germ cell through gametogenesis to the mature sperm and egg are presented. How environmental factors can influence the epigenetics of gametogenesis to impact the epigenetic transgenerational inheritance of phenotypic and physiological change in subsequent generations is reviewed.


2002 ◽  
Vol 48 (4) ◽  
pp. 526-552 ◽  
Author(s):  
Barbara Bloom ◽  
Barbara Owen ◽  
Elizabeth Piper Deschenes ◽  
Jill Rosenbaum

This article reports findings from a survey of officials from various California state agencies and a series of interviews and focus groups with female youth and professionals serving this population. The study examined types of services provided, program barriers, and facilitation of change. The findings were used to make gender-specific policy and program recommendations. The authors found that meeting the needs of girls and young women requires specialized staffing and training, particularly in terms of relationship and communication skills, gender differences in delinquency, substance abuse education, the role of abuse, developmental stages of female adolescence, and available programs and appropriate placements and limitations. Effective programming for girls and women should be shaped by and tailored to their real-world situations and problems. In order to do this, a theoretical approach to treatment that is gender-sensitive and that addresses the realities of girls' lives must be developed.


2004 ◽  
Vol 379 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Marie-Chloé BOULANGER ◽  
Tina Branscombe MIRANDA ◽  
Steven CLARKE ◽  
Marco di FRUSCIO ◽  
Beat SUTER ◽  
...  

The role of arginine methylation in Drosophila melanogaster is unknown. We identified a family of nine PRMTs (protein arginine methyltransferases) by sequence homology with mammalian arginine methyltransferases, which we have named DART1 to DART9 (Drosophilaarginine methyltransferases 1–9). In keeping with the mammalian PRMT nomenclature, DART1, DART4, DART5 and DART7 are the putative homologues of PRMT1, PRMT4, PRMT5 and PRMT7. Other DART family members have a closer resemblance to PRMT1, but do not have identifiable homologues. All nine genes are expressed in Drosophila at various developmental stages. DART1 and DART4 have arginine methyltransferase activity towards substrates, including histones and RNA-binding proteins. Amino acid analysis of the methylated arginine residues confirmed that both DART1 and DART4 catalyse the formation of asymmetrical dimethylated arginine residues and they are type I arginine methyltransferases. The presence of PRMTs in D. melanogaster suggest that flies are a suitable genetic system to study arginine methylation.


Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 402 ◽  
Author(s):  
Chenguang Wang ◽  
Chaonan Wang ◽  
Wenjie Xu ◽  
Jingze Zou ◽  
Yanhong Qiu ◽  
...  

Plants have evolved multiple mechanisms to respond to viral infection. These responses have been studied in detail at the level of host immune response and antiviral RNA silencing (RNAi). However, the possibility of epigenetic reprogramming has not been thoroughly investigated. Here, we identified the role of DNA methylation during viral infection and performed reduced representation bisulfite sequencing (RRBS) on tissues of Cucumber mosaic virus (CMV)-infected Nicotiana tabacum at various developmental stages. Differential methylated regions are enriched with CHH sequence contexts, 80% of which are located on the gene body to regulate gene expression in a temporal style. The methylated genes depressed by methyltransferase inhibition largely overlapped with methylated genes in response to viral invasion. Activation in the argonaute protein and depression in methyl donor synthase revealed the important role of dynamic methylation changes in modulating viral clearance and resistance signaling. Methylation-expression relationships were found to be required for the immune response and cellular components are necessary for the proper defense response to infection and symptom recovery.


2005 ◽  
Vol 11 (12) ◽  
pp. 1813-1814 ◽  
Author(s):  
Nina Marano ◽  
Paul Arguin ◽  
Marguerite Pappaioanou ◽  
Lonnie King
Keyword(s):  

2018 ◽  
Vol 66 (5) ◽  
pp. 379 ◽  
Author(s):  
Igor Ballego-Campos ◽  
Elder Antônio Sousa Paiva

Colleters are common among eudicotyledons, but few records exist for monocotyledons and other groups of plants. For Bromeliaceae, mucilage secretions that protect the young portions of the plant have been observed only in the reproductive axis, and little is known about the secretory systems behind this or even other kind of secretions in the family. We aimed to describe, for the first time, the occurrence of colleters associated with the vegetative shoot of Aechmea blanchetiana (Baker) L.B.Sm., and elucidate aspects of their structure, ultrastructure and secretory activity. Samples of various portions of the stem axis were prepared according to standard methods for light and electron microscopy. Colleters were found compressed in the axillary portion of leaves and in all leaf developmental stages. Secretory activity, however, was found to be restricted to young and unexpanded leaves. The colleters displayed a flattened hand-like shape formed by a multiseriate stalk and an expanded secretory portion bearing elongated marginal cells. Ultrastructural data confirmed that the secretory role of the colleters is consistent with mucilaginous secretion. The functional roles of the colleters are discussed with regard to environmental context and intrinsic features of the plant, such as the presence of a water-impounding tank.


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