A Study of some of the Factors Affecting Excystation in vitro of the Metacercarial Stages of Holostephanus lühei Szidat, 1936 and Cyathocotyle bushiensis Khan, 1962 (Strigeida: Trematoda)

1965 ◽  
Vol 39 (2-3) ◽  
pp. 185-196 ◽  
Author(s):  
David A. Erasmus ◽  
L. J. Bennett
Keyword(s):  
Cyst Wall ◽  
Final Host ◽  
Life Cycles ◽  
Digenetic Trematode ◽  
Infective Stage ◽  
Mature Adult ◽  
Factors Affecting ◽  
Varying Thickness ◽  
Sexually Mature

In many digenetic trematode life-cycles there occurs a metacercarial stage which is usually the ultimate infective stage for the final host. The metacercarial stage may be free and active as in Diplostomatidae (Strigeida) but in most cases the metacercaria is enclosed within a cyst wall of varying thickness and complexity (Erasmus, 1965). The release of the metacercaria follows the ingestion of the cyst and the digestion of the cyst wall by the appropriate final host. It is apparent that the culmination of the life-cycle in the development of a sexually mature adult will occur only if the release of the metacercaria takes place in the appropriate host. It seems very likely therefore that the factors affecting the excystation of metacercariae play an important role in defining the host specificity of a particular trematode.

Studies onOnchocerca gutturosa(Neumann, 1910) and its Development inSimulium Ornatum(Meigen, 1818). 3. Factors Affecting the Development of the Parasite in its Vector

1973 ◽  
Vol 47 (1) ◽  
pp. 73-88 ◽  
Author(s):  
D. A. Eichler
Keyword(s):  
Larval Development ◽  
Seasonal Variations ◽  
Peritrophic Membrane ◽  
Infective Stage ◽  
Infected Cattle ◽  
Factors Affecting ◽  
Dimensional Changes ◽  
Vector Activity ◽  
Migratory Route

1. Observations were made on various methods of infecting S.ornatumwith 0.gutturosa, the behaviour of the parasite in its vector, and the maintenance of the vector in the laboratory.2. S.ornatumreared from pupae brought into the laboratory were successfully infected with 0.gutturosaafter feeding on infected cattle. The use ofin vitromethods of infection was unsuccessful as microfilariae were ingested but did not undergo larval development.3. The migratory route of 0.gutturosamicrofilariae ingested by S.ornatumwas studied and it was found that a mean of only 25% penetrate out of the abdominal midgut. The dimensional changes of 0.gutturosawere noted from the time of ingestion by S.ornatumuntil the infective stage was reached.4. 0.gutturosatook 13–15 days to reach the infective stage in S.ornatumwhen maintained at a constant temperature of 23°C.5. The development and structure of the peritrophic membrane of S.ornatumare described.6. Preliminary observations on the seasonal variations of some factors affecting the transmission of O.gutturosaby S.ornatumsuggest that microfilariae were only available for ingestion during the period of vector activity, after which they migrated into the deeper regions of the skin of cattle.

FACTORS AFFECTING THE REGENERATION OF PEPPER (CAPSICUM ANNUUM L.)

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1120G-1120
Author(s):  
J. L. Jacobs ◽  
C. T. Stephens
Keyword(s):  
Growth Hormone ◽  
Silver Nitrate ◽  
Callus Formation ◽  
Leaf Explants ◽  
Regeneration System ◽  
Factors Affecting ◽  
Nitrate Concentrations ◽  
Leaf Differentiation ◽  
Whole Plants

Several growth hormone combinations and silver nitrate concentrations were examined for their effect on regeneration of different pepper genotypes. Primary leaf explants from in vitro seedlings were cultured on a revised Murashige and Skoog medium supplemented with auxin, cytokinin and 1.6% glucose. Combinations of different concentrations of indole-3-acetic acid (IAA), 0-5 mg/l, and 6-benzylaminopurine (BAP), 0-5 mg/l, were tested to determine the most effective medium for shoot primordium formation. Experiments with IAA and BAP did not result in a specific growth hormone combination appropriate for regeneration of all genotypes tested. Of the silver nitrate concentrations tested, 10 mg/l resulted in the best shoot and leaf differentiation and reduced callus formation. Differences in organogenic response of individual genotypes were evaluated on a single regeneration medium. Whole plants were regenerated from 11 of 63 genotypes examined. Based on these experiments, a reproducible regeneration system for pepper was developed with a total of 500 plants regenerated to date.

scholarly journals Silver Nanoparticles and Their Antibacterial Applications

2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Agents ◽  
Multidrug Resistant ◽  
Secondary Effects ◽  
Cytotoxic Effects ◽  
Factors Affecting ◽  
Gram Positive Bacteria ◽  
Resistant Strains

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

Activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum (Cestoda: Pseudophyllidea)

Parasitology ◽  
1981 ◽  
Vol 83 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Margaretha K. S. Gustafsson ◽  
Marianne C. Wikgren
Keyword(s):  
Neurosecretory Cells ◽  
Final Host ◽  
Fish Host ◽  
Neurosecretory System ◽  
Weak Reaction ◽  
Diphyllobothrium Dendriticum ◽  
Large Numbers ◽  
Short Times

SUMMARYThe activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum was studied following cultivation of plerocercoids for short times in vitro and in vivo. In the plerocercoid the neurosecretory cells gave a very weak reaction with paraldehyde fuchsin (PAF). After cultivation for 1 h large numbers of neurosecretory cells filled with PAF-positive granules were evident. The significance of the activation of the neurosecretory system during the transfer of the worm from the cold-blooded fish host to the warm-blooded final host is discussed.

Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

2021 ◽  
pp. 1-9
Author(s):  
Etsuo Niki
Keyword(s):  
Biological Molecules ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Beneficial Effects ◽  
Multiple Oxidants ◽  
Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

scholarly journals In vitro factors affecting the concentration of gamma-LpE (γ-LpE) in human plasma

1998 ◽  
Vol 39 (4) ◽  
pp. 861-872 ◽  
Author(s):  
Larbi Krimbou ◽  
Michel Tremblay ◽  
Hélène Jacques ◽  
Jean Davignon ◽  
Jeffrey S. Cohn
Keyword(s):  
Human Plasma ◽  
Factors Affecting

scholarly journals Lankesterella (Apicomplexa, Lankesterellidae) Blood Parasites of Passeriform Birds: Prevalence, Molecular and Morphological Characterization, with Notes on Sporozoite Persistence In Vivo and Development In Vitro

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1451
Author(s):  
Carolina Romeiro Fernandes Chagas ◽  
Josef Harl ◽  
Vytautas Preikša ◽  
Dovilė Bukauskaitė ◽  
Mikas Ilgūnas ◽  
...  
Keyword(s):  
Morphological Characterization ◽  
Life Cycles ◽  
Diagnostic Methods ◽  
Host Cells ◽  
Blood Parasites ◽  
Serinus Canaria ◽  
Long Time ◽  
Development In Vitro

Recent studies confirmed that some Hepatozoon-like blood parasites (Apicomplexa) of birds are closely related to the amphibian parasite Lankesterella minima. Little is known about the biology of these pathogens in birds, including their distribution, life cycles, specificity, vectors, and molecular characterization. Using blood samples of 641 birds from 16 species, we (i) determined the prevalence and molecular diversity of Lankesterella parasites in naturally infected birds; (ii) investigated the development of Lankesterella kabeeni in laboratory-reared mosquitoes, Culex pipiens forma molestus and Aedes aegypti; and (iii) tested experimentally the susceptibility of domestic canaries, Serinus canaria, to this parasite. This study combined molecular and morphological diagnostic methods and determined 11% prevalence of Lankesterella parasites in Acrocephalidae birds; 16 Lankesterella lineages with a certain degree of host specificity and two new species (Lankesterella vacuolata n. sp. and Lankesterella macrovacuolata n. sp.) were found and characterized. Lankesterella kabeeni (formerly Hepatozoon kabeeni) was re-described. Serinus canaria were resistant after various experimental exposures. Lankesterella sporozoites rapidly escaped from host cells in vitro. Sporozoites persisted for a long time in infected mosquitoes (up to 42 days post exposure). Our study demonstrated a high diversity of Lankesterella parasites in birds, and showed that several avian Hepatozoon-like parasites, in fact, belong to Lankesterella genus.

Maturation, iron deficiency, and ligands in enteric radioiron transport in vitro

1963 ◽  
Vol 204 (1) ◽  
pp. 171-175 ◽  
Author(s):  
W. S. Ruliffson ◽  
J. M. Hopping
Keyword(s):  
Ascorbic Acid ◽  
Iron Deficiency ◽  
Iron Absorption ◽  
Deficiency Anemia ◽  
Anaerobic Incubation ◽  
Reverse Effect ◽  
Factors Affecting ◽  
Everted Gut Sac

The effects in rats, of age, iron-deficiency anemia, and ascorbic acid, citrate, fluoride, and ethylenediaminetetraacetate (EDTA) on enteric radioiron transport were studied in vitro by an everted gut-sac technique. Sacs from young animals transported more than those from older ones. Proximal jejunal sacs from anemic animals transported more than similar sacs from nonanemic rats, but the reverse effect appeared in sacs formed from proximal duodenum. When added to media containing ascorbic acid or citrate, fluoride depressed transport as did anaerobic incubation in the presence of ascorbic acid. Anaerobic incubation in the presence of EDTA appeared to permit elevated transport. Ascorbic acid, citrate, and EDTA all enhanced the level of Fe59 appearing in serosal media. These results appear to agree with previously established in vivo phenomena and tend to validate the in vitro method as one of promise for further studies of factors affecting iron absorption and of the mechanism of iron absorption.

scholarly journals Somaclonal variation on in vitro callus culture potato cultivars

2004 ◽  
Vol 22 (2) ◽  
pp. 300-304 ◽  
Author(s):  
Patricia N. Bordallo ◽  
Derly H. Silva ◽  
José Maria ◽  
Cosme D. Cruz ◽  
Elizabeth P. Fontes
Keyword(s):  
Somaclonal Variation ◽  
Culture Media ◽  
Callus Formation ◽  
Potato Cultivars ◽  
Synthetic Seed ◽  
Arbitrary Sequence ◽  
Stem Explants ◽  
Factors Affecting ◽  
High Level

Synthetic seeds can be an alternative for those species in which botanical seeds are not viable. One of the major problems of in vitro plant cultivation is the high level of somaclonal variation. The most common factors affecting somaclonal variation are genotype, explant source, in vitro period and cultivation conditions in which the culture is established. In this work, calli were induced using leaf and stem explants of the commercial potato cultivars Achat, Baraka, Baronesa, Bintje, and Contenda in MS culture media supplemented with 1.65 mM of picloram and 11.5 mM of 2,4-D. Seventy and 90 days after induction, DNA samples of 40 calli were compared concerning the effects of the two explant (leaf and stem) and two growth regulator sources on five potatoes cultivars. A total of 20 arbitrary sequence primers were evaluated. The RAPD pattern generated by these primers suggested a high percentage of polymorphic fragments among the five genotypes, indicating a high level of genetic variation among cultivars. Cultivar Baronesa showed the highest number of polymorphic fragments for all treatments. The cultivar Contenda showed the smallest somaclonal variation, for most of the treatments, except for the treatment which consisted of stem explants, picloram (1.65 mM) application, and a 70-day period of callus formation. 'Contenda' is, therefore, the most suitable cultivar for synthetic seed production.

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