Caballeria liewi Lim, 1995, uses adhesive secretions from the head organs and posterior secretory systems to assist in locomotion and attachment. Ultrastructural investigations show that the head organs of C. liewi consist of three pairs of antero-lateral pit-like openings bearing microvilli and ducts leading from two types of uninucleated gland cells (located lateral to the pharynx), one type producing rod-like (S1) bodies with an electron-dense matrix containing less electron-dense vesicles and the second type producing oval (S2) bodies with a homogeneous electron-dense matrix. Interlinking band-like structures are observed between S1 bodies and between S2 bodies. S1 body is synthesised in the granular endoplasmic reticulum, transported to a Golgi complex to be packaged into vesicles and routed into ducts for exudation. The synthesis of the S2 body is unresolved. Haptoral secretions manifested externally as net-like structures are derived from dual electron-dense (DED) secretory body produced in the peduncular gland cells. The DED body consists of a less electron-dense oval core in a homogeneous electron-dense matrix. On exocytosis into the pyriform haptoral reservoir, DED bodies are transformed into a secretion with two types of inclusions (less electron-dense oval and electron-dense spherical inclusions) in an electron-dense matrix. The secretions are further transformed (as small, oval, electron-dense bodies) when transported to the superficial anchor grooves, and on exudation into the gill tissues, the secretions become an electron-dense matrix. Secretory bodies associated with uniciliated structures, anchor sleeves and marginal hooks are also observed.
Sexually anomalous individuals, typically intersexes or gynandromorphs, bear a mixture of male and female traits. Twelve sexually anomalous individuals of the black fly Simulium (Gomphostilbia) trangense Jitklang, Kuvangkadilok, Baimai, Takaoka & Adler were discovered among 49 adults reared from pupae. All 12 sexually anomalous adults were parasitized by mermithid nematodes, although five additional parasitized adults had no overt external anomalies. Sequence analysis of the 18S rRNA gene revealed that the mermithids, possibly representing a new species, are related to Mesomermis spp., with genetic distances of 5.09-6.87%. All 12 anomalous individuals had female phenotypical traits on the head, thorax, forelegs, midlegs, and claws, but male features on the left and right hind basitarsi. One individual had mixed male and female genitalia. The findings are in accord with the trend that mermithid infections are associated with sexually anomalous adult black flies.
Seaweeds are one of the most widely studied natural resources for their biological activities. Novel seaweed compounds with unique chemical structures have been reported for their pharmacological properties. The urge to search for novel insecticidal compound with a new mode of action for development of botanical insecticides supports the relevant scientific research on discovering the bioactive compounds in seaweeds. The mosquitocidal potential of seaweed extracts and their isolated compounds are documented in this review paper, along with the discussion on bioactivities of the major components of seaweeds such as polysaccharides, phenolics, proteins, terpenes, lipids, and halogenated compounds. The effects of seaweed extracts and compounds toward different life stages of mosquito (egg, larva, pupa, and adult), its growth, development, and reproduction are elaborated. The structure-activity relationships of mosquitocidal compounds are discussed to extrapolate the possible chemical characteristics of seaweed compounds responsible for insecticidal properties. Furthermore, the possible target sites and mode of actions of the mosquitocidal seaweed compounds are included in this paper. The potential synergistic effects between seaweeds and commercial insecticides as well as the toxic effects of seaweed extracts and compounds toward other insects and non-target organisms in the same habitat are also described. On top of that, various factors that influence the mosquitocidal potential of seaweeds, such as abiotic and biotic variables, sample preparation, test procedures, and considerations for a precise experimental design are discussed. The potential of active seaweed extracts and compounds in the development of effective bioinsecticide are also discussed.
Trichomonas vaginalis, a flagellated protozoan parasite, is commonly found in the genitourinary tract of humans. Its mode of reproduction has always been reported to be binary fission. The high parasite numbers seen in a relatively short period in in vitro cultures led us to believe that there must be other modes of reproduction. The present study for the first time provides transformational evidence at the ultrastructural level seen in tropohozoites of T. vaginalis undergoing a multiple asexual mode of reproduction. The findings show that the single cell with a nucleus is capable of dividing to as many as eight nuclei within the cytoplasmic body. Before the commencement of division, the nucleus remained round or ovoid in shape with condensed chromatin masses and only a few endoplasmic reticula surrounding the nucleus. During the division, the nucleus started to elongate and become irregular in shape with visible chromatin masses condensing with the accumulation of numerous endoplasmic reticula. Nuclear division gave rise to as many as eight nuclei within a cell, which could be seen to be connected by numerous endoplasmic reticula. In addition, a high number of hydrogenosomes and vacuoles can be seen in multinucleated T. vaginalis compared with single nucleated T. vaginalis. This study confirms that multiple modes of nuclear division do exist in T. vaginalis and are a precursor to progeny formation.
Thelohanellus kitauei is a freshwater myxosporean parasite causing intestinal giant cystic disease of common carp. To clarify the life cycle of T. kitauei, we investigated the oligochaete populations in China and Hungary. This study confirms two distinct aurantiactinomyxon morphotypes (Aurantiactinomyxon type 1 and Aurantiactinomyxon type 2) from Branchiura sowerbyi as developmental stages of the life cycle of T. kitauei. The morphological characteristics and DNA sequences of these two types are described here. Based on 18S rDNA sequence analysis, Aurantiactinomyxon type 1 (2048 bp) and Aurantiactinomyxon type 2 (2031 bp) share 99.2-99.4 %, 99.8-100 % similarity to the published sequences of T. kitauei, respectively. The 18S rDNA sequences of these two aurantiactinomyxon morphotypes share 99.4 % similarity, suggesting intraspecific variation within the taxon, possibly due to geographic origin. Phylogenetic analyses demonstrate the two aurantiactinomyxon types clustered with T. kitauei. Regardless, based on 18S rDNA synonymy, it is likely that Aurantiactinomyxon type 1 and 2 are conspecific with T. kitauei. This is the fourth elucidated two-host life cycle of Thelohanellus species and the first record of T. kitauei in Europe.
Cosmopolitan scuttle fly, Megaselia scalaris (Loew) (Diptera: Phoridae) is one of the commonest forensic species recorded colonizing human corpse indoors and in concealed environment. The occurrence of this species in such environments provides a higher evidential value to assist estimation of postmortem interval (PMI) compared to other forensically important dipterans. However, developmental and size data of M. scalaris are still lacking and they are derived from a limited range of thermal values. The objective of this study is to develop the growth model of M. scalaris by emphasizing the size range of larvae and puparia at different constant temperatures. This species was reared in six replicates at eight varying constant temperatures ranging from 23 to 36 °C and cow's liver was provided as food source. Larvae and puparia were sampled at set time intervals and measured by their length and weight. Because interpretation of forensic entomological evidence is subject to application of different techniques, development of M. scalaris is expressed herein by using developmental table, length/morphological stage diagrams and linear/nonlinear estimation methods. From the findings, it is very important to highlight that sexual dimorphism of M. scalaris during post feeding larva and pupa stage could be observed based on size and developmental periods. Mean length and weight ratios of male to female puparia are approximately 0.8 and 0.3-0.5, respectively, indicating sexual dimorphism of this species. Developmental period in female are 4.0-11.4 h (post feeding larval stage), 3.7-24.0 h (pupal stage), and 3.0-20.1 h (total developmental period) longer in male. Due to this dimorphism, PMI estimation using M. scalaris post feeding larva or puparium specimens must be carried out carefully by to avoid inaccuracy and misinterpretation.
In forensic entomology, breeding of fly larvae in a controlled laboratory environment using animal tissue is a common technique to obtain insect developmental time for the estimation of postmortem interval. Previous studies on growth media are mostly on the effect of different diets on fly development. However, the interaction effects between temperature and food type used have not been explored. The objective of this study was to compare the use of cow's liver agar and raw liver on the development of a forensically important fly, Megaselia scalaris (Loew). This study also determined the interaction between different temperatures and different food types on the growth of this species. A total of 100 M. scalaris eggs were transferred into each of the two media mentioned above. Liver agar was prepared by adding dried ground liver into nutrient agar, whilst raw liver was naturally prepared from the same animal source. This experiment was conducted at 27, 30 and 33 °C in an incubator in a continuously dark condition. Length and weight of larvae, puparia and adult samples were determined. Total developmental times for larvae feeding on liver agar at each temperature were approximately 7-15 h slower than those feeding on raw liver. Survival rates were almost equal in both diets but were lower at 33 °C. Mean larva length in both diets did not differ significantly at all temperatures, but larvae feeding on liver agar had lower mean weight values than those in raw liver at 30 and 33 °C. The effect of temperature was significant in female puparia weight and male adult weight whereas the effect of diet types was significant in both male and female puparia size and weight. Interaction effects of temperature and food type on M. scalaris puparium size and adult weight were significant, indicating that puparium size and adult weight depended on both food type and temperature. This experiment highlighted the use of cow's liver agar as an alternative diet to breed M. scalaris in the laboratory and the importance of considering the interaction effect between temperatures and food types when deciding the most suitable medium in fly larva rearing.
A morphological and molecular phylogenetic study of proteocephalid tapeworms of the genus Acanthotaenia von Linstow, 1903, parasites of monitors (Varanidae), was carried out. The type species, A. shipleyi von Linstow, 1903, which was originally described based on an immature specimen from Sri Lanka, is redescribed based on new material from the type host, Varanus salvator, in Sri Lanka, Malaysia, and Vietnam, and its neotype is designated. In addition, Acanthotaenia susanae n. sp. is described from Varanus nebulosus in Vietnam. The new species differs from congeners by the large size of the scolex, width of the rostellum and the number of testes. New molecular data (sequences of lsrDNA and cox1) revealed Acanthotaenia paraphyletic with the inclusion of Australotaenia bunthangi de Chambrier & Scholz, 2012, a parasite of Enhydris enhydris (Ophidia: Homalopsidae) in Cambodia. Molecular data confirm a wide distribution of A. shipleyi (isolates from Malaysia and Vietnam were almost identical) and indicate a strict host specificity (oioxeny) of individual species of the genus. Type specimens of four species made it possible to supplement their morphological descriptions. A survey of all species of Acanthotaenia recognised as valid is presented and the following taxonomic changes are proposed: Acanthotaenia pythonis Wahid, 1968 described from the green python, Morelia viridis, in a zoo, is transferred to Kapsulotaenia as Kapsulotaenia pythonis (Wahid, 1968) n. comb., because it possesses intrauterine eggs grouped in capsules. Acanthotaenia gracilis (Beddard, 1913) from Varanus varius in Australia is considered to be species inquirenda because its original descriptions did not contain sufficient data for adequate circumscription and differentiation from congeners and type material was not available. Generic diagnosis of Acanthotaenia is amended and a key to its seven species is provided.