scholarly journals THE DRUG-FASTNESS OF SPIROCHETES TO ARSENIC, MERCURIAL, AND IODIDE COMPOUNDS IN VITRO

1917 ◽  
Vol 25 (3) ◽  
pp. 349-362 ◽  
Author(s):  
Seinai Akatsu ◽  
Hideyo Noguchi

In the foregoing experiments we attempted to determine whether or not, by subjecting several varieties of spirochetes to increasing doses of certain chemotherapeutic agents, a gradual increase of resistance to the latter could be shown. For this purpose, pure cultures of Treponema pallidum, Treponema microdentium, and Spirochœta refringens were used against the action of salvarsan, neosalvarsan, bichloride of mercury, and iodine-iodide potassium solution in vitro. For culture media, the usual ascites-broth-tissue medium as well as solid ascites-agar-tissue medium was used. After permitting the spirochetes to grow for a fortnight in media containing certain quantities of each drug, transfers were made from tubes showing various degrees of growth to the next series of tubes containing the same drug in still higher concentrations, and similar transfers repeated every 2 weeks. The results of the experiments may be briefly summarized as follows: 1. Treponema pallidum and Treponema microdentium have, within 3 to 4 months, increased their tolerance to salvarsan and neosalvarsan to five and one-half times their original mark. With Spirochata refringens the increase was about three times. 2. Against the action of bichloride of mercury, the amount of increased tolerance of Treponema pallidum was about 35 to 70 times the original, while that of Treponema microdentium was about 10 times as much and was reached within 10 weeks. Spirochata refringens resisted 30 times the original dose. 3. There was an unmistakable increase of resistance of these spirochetes to the action of the iodine-iodide solution (Lugol's solution) when they were grown for several generations in fluid media containing the iodine solution, but the rate of increase between the initial and the acquired tolerance was slight. In general, the addition of Lugol"s solution to fluid media has a weak inhibitory influence upon the growth of the spirochetes, requiring for the total suppression of growth a quantity of over 0.7 cc. to 5 cc. of the culture media. The tolerance reached was for about three times that amount. 4. A similar tolerance phenomenon has not been established when employing a solid instead of a fluid medium containing the drugs. No explanation is offered except a suggestion that the drugs held in the agar do not enter into combination with certain tissue constituents of the medium as they are able to do with tissue elements in fluid media. This may be a factor necessary for inducing drug tolerance in these organisms in vitro. 5. The increased drug-fastness in vitro has a limit beyond which no further advance can be made. This limit varies with different species of spirochetes. 6. The acquired drug-fastness in vitro gradually disappears when the spirochetes are cultivated again in the drug-free media for several generations.

2021 ◽  
Vol 16 (2) ◽  
pp. 001-013
Author(s):  
Abwe Mercy Ngone ◽  
Lawrence Monah Ndam ◽  
Rita Mungfu Njilar ◽  
Doungous Oumar ◽  
Thomas Eku Njock

Plant tissue culture requires the optimization of growth media. Gnetum, known locally in Cameroon as “Eru” is an indigenous gymnospermous vegetable with diverse medicinal, nutritional, cultural and socio-economic values. This resource is over-exploited and expected to neighboring countries, resulting to increased scarcity in the forest. Preliminary work on the in vitro culture of nodal cuttings was faced by the problem of fungal contamination. It was therefore necessary to isolate and identify the fungal contaminant, optimize the surface sterilization of field material and compose an appropriate medium for sprouting. Pure cultures of the fungus were obtained and grown on Potato Dextrose Agar (PDA) and Sabouraud Dextrose Agar (SDA). The identification was based on the appearance of the fungal growth on plates and also on the microscopic view. This was affected by the use of keys. Gnetum explants were disinfected with the various concentrations of disinfectants, preceded in some instances by pre-treatments, as well as incorporating fungicides in the culture medium. Two different culture media were employed: the Woody Plant Medium (WPM) and the Murashige and Skoog (MS) based establishment medium (Y-1). Gnetum was found to live in association with a complex of Microsporum species. The level of contamination of cultures was reduced from 100% to 40% when pre-treated before disinfection and even lower to 10% by incorporating fungicides in the medium. Sprouting was observed in WPM. This study provides baseline information on the in vitro propagation of Gnetum and thus opens up avenues for more research to be carried out in this field.


2021 ◽  
Vol 70 (7) ◽  
Author(s):  
Souad Belkacemi ◽  
Maryam Tidjani Alou ◽  
Saber Khelaifia ◽  
Didier Raoult

To date, the axenic culture of Treponema pallidum remains a challenge in the field of microbiology despite countless attempts. Here, we conducted a comprehensive bibliographic analysis using several databases and search engines, namely Pubmed, Google scholar, Google, Web of Science and Scopus. Numerous unsuccessful empiric studies have been conducted and evaluated using as criteria dark-field microscopic observation of motile spiral shaped cells in the culture and virulence of the culture through rabbit infectivity. All of these studies failed to induce rabbit infectivity, even when deemed positive after microscopic observation leading to the misnomer of avirulent T. pallidum . In fact, this criterion was improperly chosen because not all spiral shaped cells are T. pallidum . However, these studies led to the formulation of culture media particularly favourable to the growth of several species of Treponema, including Oral Microbiology and Immunology, Zürich medium (OMIZ), Oral Treponeme Enrichment Broth (OTEB) and T-Raoult, thus allowing the increase in the number of cultivable strains of Treponema . The predicted metabolic capacities of T. pallidum show limited metabolism, also exhibited by other non-cultured and pathogenic Treponema species, in contrast to cultured Treponema species. The advent of next generation sequencing represents a turning point in this field, as the knowledge inferred from the genome can finally lead to the axenic culture of T. pallidum .


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1722
Author(s):  
Ileana Miclea ◽  
Andreea Suhani ◽  
Marius Zahan ◽  
Andrea Bunea

This study assessed the effect of jasmonic acid (JA) and salicylic acid (SA) on the in vitro development and production of Lavandula angustifolia Mill. plant material, and the accumulation of polyphenols, chlorophylls, and carotenoids in explants. Results were compared with explants grown in control media and with in-vivo-grown mature and young L. angustifolia plants. After 21 days of incubation, all explants propagated on low-SA-concentration or elicitor-free media produced a greater number of shoots than explants cultivated on media with higher elicitor concentrations. Shoots grew taller when activated charcoal (AC) was added to the elicitor-supplemented media, while AC negatively affected or had no effect on the phytochemical composition of plants. Explants grown in the presence of elicitors had higher polyphenolic and chlorophyll content than the controls, demonstrating the beneficial impact of elicitors on the secretion of secondary metabolites. Lutein and β-carotene were the dominating carotenoids in all samples. Culture media supplemented with 0.5 mg/L JA and 1.5 mg/L SA + AC proved the most suitable to produce plant material with high polyphenol and carotenoid content, comparable with in-vivo-grown plants.


1922 ◽  
Vol 36 (4) ◽  
pp. 393-397 ◽  
Author(s):  
Albert Fischer

An artificial organism, if one may so term it, composed of a complex of tissues, was cultivated for a long period of time. Small fragments of intestine from chick embryos 20 to 21 days old were placed in a suitable medium. The epithelium proliferated and completely covered the fragment of intestine after 4 to 6 days. A small body was thus formed, round or oblong in shape, surrounded by cylindrical epithelium and containing epithelial, connective, and muscle tissues, endothelium, and ameboid cells. After a month's cultivation in vitro, no necrosis had occurred. Therefore, it may be assumed that, through the intestinal epithelium, the medium supplied the intestinal tissue with sufficient nourishment. No uncontrolled proliferation took place after the epithelium bad surrounded the entire fragment. The cultivation of complex tissues will facilitate the study of the interactions of the different cells under various conditions. In some experiments, pure cultures of epithelial cells were grafted into such an "organism" without difficulty. The growth of malignant cells could be studied in the same way. When the "organism" was placed in a fluid medium, the epithelium remained normal but the stroma disappeared. It seems that plasma played an important rôle in the maintenance of the tissues in their normal condition.


1923 ◽  
Vol 38 (4) ◽  
pp. 407-418 ◽  
Author(s):  
Alexis Carrel

1. A method has been developed which allows the continuous growth of pure strains of fibroblasts, epithelium, and leucocytes in a medium which undergoes but slight spontaneous deterioration. 2. The principle of the method is to leave the tissues undisturbed while the medium is changed. This was realized by special containers allowing the change of the medium without bacterial contamination and by the simultaneous use of a solid and a fluid medium. 3. The curve of growth of pure cultures of fibroblasts and epithelial cells in a nutrient medium is a parabola; in a non-nutrient medium, it is S-shaped and expresses the residual activity of the tissues. Leucocytes invade the culture medium progressively, as do bacteria, but never aggregate in a tissue. 4. The method is used for the study of the morphological and dynamic changes occurring in tissues under the influence of chemical and physical factors.


2020 ◽  
Vol 25 ◽  
pp. 06003
Author(s):  
Julia Kashchits ◽  
Galina Yakuba

On the territory of the Krasnodar region, anthracnose root rot, the causative agent Colletotrichum аcutatum Simmonds, is one of the most harmful diseases in the mother plants of garden strawberry. The death of affected plants ranges from 33 to 100 %. Purpose of the research was to study the morphological and cultural characteristics of the causative agent of anthracnose root rot in the mother plant of garden strawberries in the region and to assess the effectiveness of fungicides in controlling the pathogen. The studies were carried out at FGBNU SKFNTSSVV in 2018-2020 using generally accepted techniques. The object of the research is pure cultures of C. acutatum. The morphological and cultural characteristics of C. acutatum were studied on three culture media. A high diversity of the identified morphotypes was shown in terms of the size of conidia and conidiophores, the shape and color of apressoria, and the method of formation of acervules. The influence of seven fungicides of various chemical classes on the development of C. аcutatum spores has been assessed. Under in vitro conditions at the indicated concentrations, the preparations Luna Tranquility, SC (0,15 %), Sercadis Plus, SC (0,1 and 0,15 %), Strobi, WG (0,05 %), Horus, WG (0,04 %) and Skor, EC (0,04 and 0,05 %) completely prevented the formation of fungal spores.


SPERMOVA ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 46-52
Author(s):  
Irving Laines-Arce ◽  
◽  
Mijail Contreras ◽  
Cesar Olaguivel

The present study aims to evaluate the effect of two culture media on the production of in vitro embryos in alpacas (Vicugna pacos). The ovaries were transported at 10.52° C in 0.9% saline solution supplemented with gentamicin. The ovaries were transported at 10.52° C in 0.9% physiological saline solution supplemented with gentamicin. 492 ovaries were used throughout the experiment. 2142 oocytes of quality I, II and III were recovered. The oocytes were matured in vitro for 32 h and were subsequently fertilized (incubated for 18 h) with sperm obtained from the tail of the epididymis and selected with a 45/90 percoll gradient. Then, the presumed zygotes were denuded from the cumulus cells, to later be cultured in two culture media: synthetic oviductal fluid medium (SOFaa) and simple optimized potassium medium (KSOMaa) and incubated at 38.5 ° C, 5 % CO2, 5%, O2, and 90% relative humidity for 7 days. Morula and blastocyst rate evaluation was performed at the end of embryo culture. The morula rate at 7 days was 41.49 ± 10.52 and 41.51 ± 6.50% for KSOMaa and SOFaa, respectively (P <0.05). The blastocyst rate for the two culture media KSOMaa and SOFaa, was 14.08 ± 5.17 and 11.73 ± 5.69 %, respectively, and there were no statistical differences (P˃0.05). The embryonic quality in KSOMaa and SOFaa media did not show statistical differences. In conclusion, the KSOMaa and SOFaa culture medium can be used in the production of in vitro embryos of alpacas


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e5788 ◽  
Author(s):  
Benoit Houeix ◽  
Michael T. Cairns

Background Sialyltransferases (SIATs) are a family of enzymes that transfer sialic acid (Sia) to glycan chains on glycoproteins, glycolipids, and oligosaccharides. They play key roles in determining cell–cell and cell-matrix interactions and are important in neuronal development, immune regulation, protein stability and clearance. Most fully characterized SIATs are of mammalian origin and these have been used for in vitro and in vivo modification of glycans. Additional versatility could be achieved by the use of animal SIATs from other species that live in much more variable environments. Our aim was to generate a panel of stable CHO cell lines expressing a range of vertebrate SIATs with different physicochemical and functional properties. Methods The soluble forms of various animal ST6Gal and ST3Gal enzymes were stably expressed from a Gateway-modified secretion vector in CHO cells. The secreted proteins were IMAC-purified from serum-free media. Functionality of the protein was initially assessed by lectin binding to the host CHO cells. Activity of purified proteins was determined by a number of approaches that included a phosphate-linked sialyltransferase assay, HILIC-HPLC identification of sialyllactose products and enzyme-linked lectin assay (ELLA). Results A range of sialyltransferase from mammals, birds and fish were stably expressed in CHO Flp-In cells. The stable cell lines expressing ST6Gal1 modify the glycans on the surface of the CHO cells as detected by fluorescently labelled lectin microscopy. The catalytic domains, as isolated by Ni Sepharose from culture media, have enzymatic activities comparable to commercial enzymes. Sialyllactoses were identified by HILIC-HPLC on incubation of the enzymes from lactose or whey permeate. The enzymes also increased SNA-I labelling of asialofetuin when incubated in a plate format. Conclusion Stable cell lines are available that may provide options for the in vivo sialylation of glycoproteins. Proteins are active and should display a variety of biological and physicochemical properties based on the animal source of the enzyme.


1999 ◽  
Vol 1999 ◽  
pp. 62-62
Author(s):  
N.C. Farrar ◽  
M.E. Staines ◽  
G.J. McCallum ◽  
P. Haggarty ◽  
J.J. Robinson ◽  
...  

Serum, which is routinely included in many embryo culture media, can decrease the viability of bovine and ovine embryos produced in cultures employing synthetic oviduct fluid (SOF; Kuran et al., 1999) and represents a possible route for transmission of disease. Alternative approaches include the use of chemically defined culture media but results from studies which avoid sera and its derivatives (e.g., albumin) are generally less favourable due to a lack of knowledge regarding the embryo's response to specific nutrients, most notably fatty acids. As a preliminary step towards investigating fatty acid influences on bovine embryo developmentin vitro, the present study examined the effect of adding palmitic acid (C16:0) to SOF plus bovine serum albumin (BSA) on the performance of this semi-defined culture medium and contrasted it with embryo production in SOF supplemented with serum.


1970 ◽  
Vol 48 (2) ◽  
pp. 131-138 ◽  
Author(s):  
R. Keeler

After bilateral nephrectomy total body muramidase in the rat increased by more than 50%. The mean rate of increase was 340 μg/h per 100 g. Skin and bone showed the greatest increase. Although the lungs contain a high level of muramidase there was no significant change in the level of enzyme activity after nephrectomy. Rats with sectioned ureters or with a uretero–venous anastomosis did not develop high plasma levels of muramidase. The response to nephrectomy is therefore not a response to uremia. Pretreatment of the animals with cortisone or DL-ethionine had no effect on the enzyme response to nephrectomy. This was taken to indicate that the response was not to antigenic material and did not depend upon hepatic synthesis of the enzyme. Pretreatment with the cytotoxic agent cyclophosphamide reduced the plasma and total body level of muramidase and blocked the response to nephrectomy. Direct measurement demonstrated a large increase in the rate of muramidase production by bone marrow. Since the in vitro inactivation of muramidase by kidney tissue could not be demonstrated, it is concluded that nephrectomy causes an increase in the rate of enzyme production rather than a failure of catabolism. Renal tissue might normally exert an inhibitory influence upon muramidase formation.


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