9 research outputs found

    Development of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) in Helicoverpa (Lepidoptera : Noctuidae) host eggs

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    Morphological studies of development of the egg parasitoid Trichogramma australicum Girault in the cotton bollworm, Helicoverpa armigera (Hubner), were conducted to provide benchmarks for assessing developmental rates in both natural hosts and artificial diets. Observations of living embryos and histological sections show that embryos proceed rapidly through cleavage and blastoderm formation and show a characteristic pinching or rotation 8 h after deposition. Eggs progressively increase in volume, primarily by increasing in diameter at the widest point. At 29 rectangle 1 C the duration of the egg stage is 22-24 h, the larval stage 27 h, the prepupal stage 50-52 h, and pupa 85 h. Larvae undergo dramatic shape changes as they ingest food but do not show signs of larval moults, reinforcing observations that there is only one larval instar. Criteria for staging the embryonic and postembryonic development in natural hosts will be used for future studies aimed at developing and refining artificial diets for Trichogramma

    Anatomy of the mouthparts and digestive tract during feeding in larvae of the parasitoid wasp Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae)

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    To aid in the development of artificial diets for mass rearing parasitioids, we investigated the anatomical changes in the digestive tract during feeding behaviour of larval Trichogramma australicum (Hymenoptera: Trichogrammatidae). Larvae begin to feed immediately upon eclosion and feed continuously for 4 h until replete. Feeding is characterised by rhythmic muscle contractions (ca 1 per s) of the pharynx. Contractions of the pharyngeal dilator muscles lift the roof of the lobe-shaped pharynx away from the floor of the chamber, opening the mouth and pumping food into the pharyngeal cavity. Another muscle contraction occurs about 0.5 s later, forcing the bolus of food through the oesophagus and into the midgut. The junction of fore- and midgut is marked by a cardiac valve. The midgut occupies most of the body cavity and is lined with highly vacuolated, flattened cells and a dispersed layer of muscle cells. In the centre of the midgut, food has the appearance of host egg contents. Food near the midgut epithelial cells has a finer, more homogeneous appearance. This change in the physical properties of the gut contents is indicative of the digestion process. In the prepupa, where digestion is complete, the entire gut contents have this appearance. After eclosion, the vitelline membrane remains attached to the posterior end of the larva. We believe this attachment to be adaptive in two ways: (1) to anchor the larva against the movements of its anterior portion, thereby increasing the efficiency of foraging within the egg, and (2) to prevent a free-floating membrane from clogging the mouthparts during ingestion. 1998 Elsevier Science Ltd. All rights reserved

    The effect of parasitization by Trichogramma australicum on Helicoverpa armigera host eggs and embryos

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    Histological investigations of the pathology of Helicoverpa armigera (Hiibner) eggs after attack by the egg parasitoid, Trichogramma australicum (Girault), indicate that the developing embryo is immediately killed by envenomation. Soon afterward the histological staining characteristics of parasitized host embryos change and the embryonic germ band dissociates into a mass of individual rounded cells. Hosts attacked by females sterilized by gamma-irradiation showed the same pathological effects as normally parasitized hosts, indicating that host degeneration is due to female venom rather than factors derived from the parasitoid embryo or larva. Cell death also occurred in older host embryos although tissue breakdown was delayed. These findings have allowed us to determine not just that the host dies but what happens to the cells and tissues, i.e., their physical appearance, the time course of their degeneration, and that the process is retarded in older hosts. These processes can possibly be emulated in artificial diets. (C) 2003 Elsevier Inc. All rights reserved

    Structure of the gut contents of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) larvae fixed in situ in eggs of its host Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

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    Trichogramma australicum larvae develop most rapidly in younger eggs of its host, the pest lepidopteran Helicoverpa armigera . To establish how the developmental stage of the host affects the diet of T. australicum , larvae were fixed in situ in eggs of H. armigera of different ages and the structure of the egg contents and parasitoid gut contents examined histologically. Larvae feeding on newly laid host eggs contain primarily yolk particles in their gut, while larvae feeding on older hosts contain necrotic cells and yolk particles. The gut of T. australicum larvae does not contain organised tissue remnants, indicating that larvae feed primarily by sucking food into their pharynx and feed best on a mixture of particulate semisolids in a liquid matrix. Secretory structures of T. australicum larvae that could be involved in modifying the host environment were examined. The hindgut is modified to form an anal vesicle with a number of attributes suggesting that it may be a specialised secretory structure. The paired salivary glands open to the exterior via a common duct

    Detection effect toxins produced by some types of fungi isolated from medicinal plants

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    Medicinal plants accompany many fungi belonging to different groups, including different types of zygomycotina, ascomycotina, deuteromycotina and yeasts (yeasts). Some of these fungi accompany the plant during its growth in the field and others contaminate weeds during Harvest and storage process. The fungi that infect crops were divided by Christensen (1965) into three groups. The first group includes the field fungi, which infect agricultural crops before harvest, and includes species belonging to the genera Alternaria, Fusarium, Helminthosporium, and Cladosporium. The second group is known as storage fungi, and includes fungi that attack crops. agricultural crops during storage. It includes species of the genus Aspergillus and Penicillium, These fungi are characterized by the fact that most of them produce toxins (Mycotoxins), which cause diseases to humans and animals when consuming crops contaminated with them. The third group includes rot fungi (RootFungi) that grow on the remains of plant materials and include: Chaetomiumspp, Papulosporaspp, Fusarium graminearum and Sordaria spp and found that most of the toxin-producing fungi belong to storage fungi and a few of them belong to rotting fungi that have the ability to produce toxins

    A multinational cross-sectional study on the awareness and concerns of healthcare providers toward monkeypox and the promotion of the monkeypox vaccination

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    BackgroundThe aim of this study was to explore potential healthcare workers' (HCWs) concerns about the monkeypox virus in order to create practical solutions to manage this disease.MethodsOnline cross-sectional research was conducted in 11 Arabic countries (Egypt, Saudi Arabia, Yemen, Syria, Libya, Algeria, Tunisia, Iraq, Palestine, Jordan, and Sudan) from 2 August 2022 to 28 December 2022.ResultsApproximately 82% of respondents felt the need to acquire further information. The acceptability of the vaccine against monkeypox has been indicated by more than half of the participants (54.5%). Furthermore, we state that 45% of the participants are knowledgeable about the monkeypox virus, and 53.1% of the participants have never been affected with COVID-19 before are more worried about COVID-19 than about monkeypox. Participants diagnosed with COVID-19 were 0.63 times less likely to worry about monkeypox than those who were not diagnosed with COVID-19. A greater willingness to get the monkeypox vaccination was seen among the age group 21–30 years (42.4%) compared to the other age groups.ConclusionMost healthcare professionals have a moderate knowledge of the monkeypox virus. Furthermore, they demonstrated a low willingness to get the vaccination against the monkeypox virus
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