Some aspects of the fine structure of the alimentary tract of the infective larva of Breinlia sergenti (Nematoda: Filarioidea).

The fine structure of the alimentary tract of the infective larva of Breinlia sergenti has been studied. The possible derivation of the oesophagus from the pharyngeal thread of the microfilaria is discussed.     

Some ultrastructural observations on the microfilaria of Breinlia sergenti—The excretory complex,rectal cells and anal vesicle

The present investigations describe the fine structure of the excretory complex, rectal cells and the anal vesicle of the microfilaria of Breinlia sergenti. The structure of the excretory cell and rectal cells is found to be similar to nerve cells. Axonal (digitiform) processes in the excretory and anal vesicles are described and a possible sensory function is ascribed to these structures.     

Some ultrastructural observations on the microfilaria of Breinlia sergenti--nervous system

The amphids, cephalic papillae, phasmids, excretory complex, anal vesicle, rectal cells, G cell and the nerve ring are described in the microfilaria of Breinlia sergenti. The significance of these various structures in playing a nervous role in this organism is discussed, and a working hypothesis presented to explain the nervous co-ordination in this parasitic stage.     

In vitro activity of levamisole on the infective larvae, microfilariae and adult worms of Breinlia Sergenti

In vitro activity of levamisole on the infective larvae, microfilariae and adult worms of Breinlia sergenti. International Journal for Parasitology4: 207–210. Levamisole shows in vitro activity against the infective larvae, microfilariae and adult worms of Breinlia sergenti. The polygraph studies using the adult worms indicate that levamisole causes an increase in the muscle tone; this action being dose related. The adult worms are more sensitive to the drug than the infective larvae and microfilariae. In vitro, levamisole is more potent compared with diethylcarbamazine against all the three stages of B. sergenti.     

The ultrastructure of the microfilaria of Brugia, Nematoda: Filarioidea

The microfilaria of Brugia pahangi is a differentiated nematode larva. The basic nematode body plan is present showing cuticle, hypodermis, dorsal, ventral, and lateral cords, muscle cells, longitudinal nerves, papillary nerves, amphids and phasmids. Secretory granules are present in ganglionic cells and in axons in the nerve ring. There is no differentiated pseudocoelom. There is only a single row of muscle cells between each pair of cords. The excretory cell complex is similar in structure to the hypodermal gland cells of other nematodes. The alimentary canal of the microfilaria is very much modified. The pharyngeal cells are attached to the pharyngeal thread which is circular in cross section and there is no pharyngeal musculature. The intestine is represented by the solid mass of the inner body within paired intestinal cells. The intestine is separated from the rectum. The three rectal cells form a syncytium of villi in the anal vesicle. The structure in Brugia is related to the ultrastructure of other microfilariae and it is concluded that the evolution of the modifications of the basic larval structure is due to the small size of these nematodes as a consequence of their adaptation to a parasitic mode of life in the capillaries of the vertebrate host with transmission through an intermediate arthropod vector.     

The first stage larva of brugia pahangi in Aedes togoi: An ultrastructural study

Lehane M. J. 1978. The first stage larva of Brugi pahangi in Aedes togoi: an ultrastructural study. International Journal for Parasitology8: 207–218. The ultrastructure of the first stage larva in the mosquito is described up to the onset of the first cuticular moult. The following structural changes from the microfilarial stage have been noted at this time; the numbers of muscle cells have increased, usually to four with a maximum of six in each intercordai quadrant ; part of the pharyngeal thread has formed into a knot ; the intestinal lumen has developed and is surrounded in any given transverse section by up to four intestinal cells and the inner body has largely been lost; the anal apparatus has enlarged and developed; the excretory apparatus has largely degenerated. The functional morphology of the various organ systems described is discussed.     

The life cycle and host specificity of Psychodiella sergenti n. sp. and Ps. tobbi n. sp. (Protozoa: Apicomplexa) in sand flies Phlebotomus sergenti and Ph. tobbi (Diptera: Psychodidae)

Two new gregarines in the recently erected genus Psychodiella (formerly Ascogregarina), Psychodiella sergenti n. sp. and Psychodiella tobbi n. sp., are described based on morphology and life cycle observations conducted on larvae and adults of their natural hosts, the sand flies Phlebotomus sergenti and Phlebotomus tobbi, respectively. The phylogenetic analyses inferred from small subunit ribosomal DNA (SSU rDNA) sequences indicate the monophyly of newly described species with Psychodiella chagasi. Ps. sergenti n. sp. and Ps. tobbi n. sp. significantly differ from each other in the life cycle and in the size of life stages. The sexual development of Ps. sergenti n. sp. (syzygy, formation of gametocysts and oocysts) takes place exclusively in blood-fed Ph. sergenti females, while the sexual development of Ps. tobbi n. sp. takes place also in males and unfed females of Ph. tobbi. The susceptibility of Phlebotomus perniciosus, Phlebotomus papatasi, Ph. sergenti, Ph. tobbi, and Phlebotomus arabicus to both gregarines was examined by exposing 1st instar larvae to parasite oocysts. High host specificity was observed, as both gregarines were able to fully develop and complete regularly the life cycle only in their natural hosts. Both gregarines are considered as serious pathogens in laboratory-reared colonies of Old World sand flies.     

Ultrastructural studies on the microfilaria of Cardianema sp. Alicata, 1933 (Nematoda; Onchocercidae)

The ultrastructure of the sheath, cuticle and hypodermis of the microfilaria of Cardianema sp, is described from electron micrographs of in utero- and blood-stages. The trilaminiar sheath invests the microfilaria throughout development in utero and it acquires a superficial coat after the microfilaria enters the blood stream of its reptile host. The cuticle consists of external and internal cortex, fibrillar and subfibrillar layers. The cuticle is attached to the hypodermis without the intervention of a basal lamina. The structure of the external cortex is modified in the annular furrows in the cuticle. The cellular hypodermis forms a complete subcuticular layer, although over much of the circumference the cells exist as thin cytoplasmic processes and where these overlap there are extensive tight junctions. The case for classifying the microfilaria of Cardianema a first stage larva is advanced and a functional but speculative, role for the sheath is proposed.     

Detecting and differentiating Theileria sergenti and Theileria sinensis in cattle and yaks by PCR based on major piroplasm surface protein (MPSP)

Theileria sergenti and Theileria sinensis are closely related members of benign Theileria species found in cattle and yaks in China. They are morphologically indistinguishable. A polymerase chain reaction (PCR) targeting major piroplasm surface protein of T. sergenti and T. sinensis was developed in this study. The newly developed oligonucleotide primer set was able to specifically amplify the DNA of T. sinensis and in conjunction with primers for T. sergenti and these two species could be detected and distinguished. Specificity testing also revealed that there was no cross-reaction with the other tick-borne diseases Theileria annulata, Babesia ovata, Anaplasma marginale as well as bovine white blood cells. Phylogenetic analysis based on the MPSP gene sequences confirmed the specificity of PCR assays. The sensitivity of the methods was 0.1 pg DNA for the T. sergenti PCR and 1 pg DNA for T. sinensis PCR. Two hundred and thirty-six field blood samples from of cattle and yaks were collected from five different geographical regions in China where benign Theileria species have been found. T. sergenti was found in all five provinces but was absent from one county in Gansu Province. T. sinensis was only found in Gansu Province. In both counties in Gansu where the parasites co-existed, mixed infections were detected. Our results indicate that the PCR methods developed in this study are suitable for the detection and differentiation of T. sergenti and T. sinensis.     

Phlebotomus sergenti in a Cutaneous Leishmaniasis Focus in Azilal Province (High Atlas,Morocco): Molecular Detection and Genotyping of Leishmania tropica,and Feeding Behavior

Background Phlebotomus (Paraphlebotomus) sergenti is at least one of the confirmed vectors for the transmission of cutaneous leishmaniasis caused by Leishmania tropica and distributed widely in Morocco. This form of leishmaniasis is considered largely as anthroponotic, although dogs were found infected with Leishmania tropica, suggestive of zoonosis in some rural areas.ConclusionOur findings supported the notion that Phlebotomus sergenti is the primary vector of Leishmania tropica in this focus, and that the latter is genetically very heterogeneous. Furthermore, our results might be suggestive of a certain level of heterozygosity in Leishmania tropica population. This finding, as well as the feeding of the vectors on different animals are of interest for further investigation.     

The responses to various stimuli of microfilariae of Dirofilaria corynodes, of Dipetalonema marmosetae and of unidentified species of filariae in Saimiri sciureus and Cacajao monkeys

Hawking F. 1973. The responses to various stimuli of microfilariae of Dirofilaria corynodes, of Dipetalonema marmosetae and of unidentified species of filariae in Saimiri sciureus and Cacajao monkeys. International Journal for Parasitology3: 433–439. A study was made of the responses of the microfilariae of Dirofilaria corynodes, of Dipetalonema marmosetae and of three unknown filariae in Saimiri sciureus and of three other unknown ones in Cacajao rubicundus, to various stimuli applied to the host. These stimuli included exposure of the host to high oxygen or to hypoxia, intravenous injection of acetylcholine or serotonin, and alteration of body temperature. One of the unidentified microfilariae of S. sciureus was thermosensitive and its 24 h cycle is probably controlled by the temperature cycle of its host. The microfilaria of D. corynodes was liberated from the lungs by intravenous injection of acetylcholine and serotonin, thus resembling the microfilariae of D. immitis and D. repens.     

The Effects of Ivermectin on Brugia malayi Females In Vitro: A Transcriptomic Approach

BackgroundLymphatic filariasis and onchocerciasis are disabling and disfiguring neglected tropical diseases of major importance in developing countries. Ivermectin is the drug of choice for mass drug administration programs for the control of onchocerciasis and lymphatic filariasis in areas where the diseases are co-endemic. Although ivermectin paralyzes somatic and pharyngeal muscles in many nematodes, these actions are poorly characterized in adult filariae. We hypothesize that paralysis of pharyngeal pumping by ivermectin in filariae could result in deprivation of essential nutrients, especially iron, inducing a wide range of responses evidenced by altered gene expression, changes in metabolic pathways, and altered developmental states in embryos. Previous studies have shown that ivermectin treatment significantly reduces microfilariae release from females within four days of exposure in vivo, while not markedly affecting adult worms. However, the mechanisms responsible for reduced production of microfilariae are poorly understood.Conclusion/SignificanceThese changes provide insight into the mechanisms involved in ivermectin-induced reduction in microfilaria output and impaired fertility, embryogenesis, and larval development.     

Addition of hydrazoic acid to methyl 6-O-benzoyl-2,3-dideoxy-α-D-glycero-hex-2-enopyranosid-4-ulose

The title compound 4 reacted with hydrazoic acid to give exclusively an adduct having the threo configuration, whose structure was established by reduction to the lyxo derivatives 8 and 10. The reaction of 4 with hydrogen peroxide afforded the epoxide 12, the lyxo structure of which was deduced by conversion into the alcohol 13. Tributylborane also reacted with the enone 4, giving the adduct 15, whose configuration was tentatively assigned to be threo.     

Erythrinoid and indol alkaloids isolated from the seeds of Erythrina rubrinervia Kunth: Chemotaxonomic significance

In the present work, we report the isolation of five alkaloids from the seeds of Erythrina rubrinervia. Four of the isolated alkaloids are erythrinoid type alkaloids which were identified as erysodine (1), erysovine (2), erythraline (3) and erysotrine (4), plus an indolic alkaloid which was identified as hypaphorine (5). The analysis of spectroscopic data for the alkaloid l-hypaphorine shows that the published structure (5a) must be revised, and the correct structure is that depicted as the structure 5c. The chemical structures were elucidated by full spectroscopic analysis. The chemotaxonomic significance of those findings in the genus Erythrina is also discussed.     

Molecular detection of Leishmania tropica in field caught Phlebotomus sand flies (Diptera: Psychodidae) from cutaneous leishmaniasis endemic focus of Pakistan

Cutaneous Leishmaniasis is endemic in tribal district Khyber for last more than one decade. The causative agent Leishmania tropica is known but sand fly species responsible for the transmission of disease still needs to be investigated. A total of 2647 Phlebotomus females belonging to 11 species were divided into 435 batches and subjected to PCR for detection of Leishmania in sand flies. A total of 50 batches belonging to three species i.e. Phlebotomus sergenti, Phlebotomus papatasi and Phlebotomus alexandri were detected positive for Leishmania tropica. Overall minimum infection rate was 1.89% (50/2647). Highest minimum infection rate of 2.11% (39/1710) was observed for Phlebotomus sergenti followed by 1.21% (8/661) for Phlebotomus paptasi and 1.82% (3/165) for Phlebotomus alexandri. Both blood fed (38%) and unfed (62%) sand flies were detected positive for the parasite DNA. Positive specimens were collected throughout the active season, from all collection sites of the study area. Detection of Leishmania parasite in multiple species of Phlebotomus indicates the possible role of these species as vector of disease in the tribal district Khyber of Pakistan. It also indicates the probable complex transmission cycle of the disease involving multiple vector species in the study area. Devising a control strategy by focusing on these vector species, may reduce the disease burden in the cutaneous leishmaniasis endemic tribal district Khyber.     

Stilbenes of Gnetum ula

Gnetin, a new stilbene isolated from Gnetum ula is assigned the structure 3,4-methylenedioxy-4′-methoxy-trans-stilbene, 3 on the basis of spectroscopic data and synthesis. The structure 3,3′,4-trihydroxy-2-methoxy-trans-stilbene, 1a earlier assigned to a trihydroxymonomethoxy stilbene is now revised to 3,4,5′-trihydroxy-3′-methoxy-trans-stilbene, 1b.     

Structural revision of kynapcin-12 by total synthesis,and inhibitory activities against prolyl oligopeptidase and cancer cells

Kynapcin-12 is a prolyl oligopeptidase (POP) inhibitor isolated from Polyozellus multiplex, and its structure was assigned as 1 having a p-hydroquinone moiety by spectroscopic analyses and chemical means. This Letter describes the total syntheses of the proposed structure 1 for kynapcin-12 and 2′,3′-diacetoxy-1,5′,6′,4″-tetrahydroxy-p-terphenyl 2 isolated from Boletopsis grisea, revising the structure of kynapcin-12 to the latter. These syntheses involved double Suzuki–Miyaura coupling, CAN oxidation, and LTA oxidation as key steps. The inhibitory activities of synthetic compounds against POP and cancer cells were also evaluated.     

]Hexitol derivatives containing a 1,4-oxathiane ring

The synthesis of 2,5-anhydro-3-O-methylsulfonyl-6-thio-1,4-thioanhydro-D-galactitol (4; type A structure) and 2,5-anhydro-3,4-di-O-methylsulfonyl-1,6-thioanhydro-D-glucitol (10, type B structure), starting from 2,5-anhydro-1,6-dibromo-1,6-dideoxy-3,4-di-O-methylsulfonyl-D-glucitol (1) is described. The 4-O-methyl-sulfonyl group of 10 can be displaced by nucleophiles with retention of configuration. In this reaction, a cyclic sulfonium intermediate 21 is involved, which, depending on the nucleophilicity of the anion, leads to different ratios of type A and B compounds. Introduction of a three-membered ring into the 3,4-position of type B compounds yielded tricyclic derivatives of allitol.