Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Fungi of the genus Penicillium as producers of physiologically active compounds (Review)

Fungi of the genus Penicillium isolated from little studied habitats are able to synthesize both previously known and new physiologically active compounds with diverse structures. They include secondary metabolites of alkaloid nature, i.e., ergot alkaloids, diketopiperazines, quinolines, quinazolines, benzodiazepines, and polyketides. We discuss the use of profiles of secondary metabolites for taxonomy purposes. Studying the physicochemical characteristics of producers of biologically active compounds showed that the biosynthesis of alkaloids is initiated on the first days of cultivation and proceeds simultaneously with growth. The cyclic character of alkaloid accumulation was recorded related to the processes of alkaloid biosynthesis, excretion from cells, degradation in culture fluid, and consumption by cells. Synchronic variations in the concentrations of intracellular tryptophan and alkaloids are necessary for the regulation of the optimal quantity of tryptophan necessary for the culture.     

Taxonomic position and nitrogen-containing secondary metabolites of the fungus Penicillium vitale Pidoplichko Et Bilai Apud Bilai

The type strain Penicillium vitale Pidoplichko et Bilai apud Bilai 1961 VKM F-3624 was found to considerably differ from a sibling species P. janthinellium (syn. P. simplicissimum) in some physiological and morphological features (growth rates at different temperatures, the size of philiades, and the shape of conidia), as well as in the pattern of the nitrogen-containing secondary metabolites produced (roquefortine, 3,12-dihydroroquefortine, meleagrin, aurantioclavine, indole-3-acetic acid, and N-acetyltryptamine). The data obtained suggest that P. vitale represent an independent species.     

Extramedullary hematopoiesis in a case of benign mixed mammary tumor in a female dog: cytological and histopathological assessment

Backgroud  

Extramedullary hematopoiesis (EMH) is defined as the presence of hematopoietic stem cells such as erythroid and myeloid lineage plus megakaryocytes in extramedullary sites like liver, spleen and lymph nodes and is usually associated with either bone marrow or hematological disorders. Mammary EMH is a rare condition either in human and veterinary medicine and can be associated with benign mixed mammary tumors, similarly to that described in this case.     

Transport of ergot alkaloids and quinocitrinins in the producing fungus Penicillium citrinum

The decrease in the concentration of alkaloids in the culture liquid of Penicillium citrinum grown to the early stationary phase was found to be due to the uptake of quinocitrinins and ergot alkaloids by fungal cells. The ability of the fungal mycelium to absorb autogenous quinocitrinins does not depend on the mycelium age, whereas its ability to absorb ergot alkaloids is higher in the young than in the 12-day-old mycelium. The uptake of exogenously added ergot alkaloids by the fungal mycelium is accompanied by excretion of intracellular quinocitrinins. The addition of quinocitrinins to the medium was found to exert different effects in different growth stages. Namely, the uptake of exogenously added quinocitrinins by the actively growing young mycelium inhibits the excretion of ergot alkaloids, but the excretion of ergot alkaloids by the 12- day-old mycelium occurs throughout the cultivation period. The excretion of both ergot alkaloids and quinocitrinins does not require energy.     

Fungus Penicillium citrinum, isolated from permafrost sediments, as a producer of ergot alkaloids and new quinoline alkaloids quinocitrinines

Quinocitrinines and ergot alkaloids are synthesized by the strain Penicillium citrinum VKM FW-800 as the culture grows. The major part of these secondary metabolites are secreted into the medium. In the phase of growth deceleration, these metabolites were partly absorbed by the producer cells. Zinc ions stimulated both the primary and secondary metabolic processes. Addition of this microelement into the culture medium stimulated biomass accumulation and the synthesis of clavine alkaloids and quinocitrinines.     

The fungus Penicillium variabile Sopp 1912 isolated from permafrost deposits as a producer of rugulovasines

It has been established that relict fungi Penicillium variabile Sopp can synthesize clavine alkaloids, rugulovasines A and B, which are revealed in this species for the first time. Submerged cultivation of the strain-producer revealed several microcycles of conidia formation. The synthesis of alkaloids was also of a cyclic character. The synchronism of cyclic rugulovasine biosynthesis and conidia formation was revealed. Zinc ions stimulated fungal growth but had a negative effect on the biosynthesis of rugulovasines.     

Penicillium expansum, a Resident Fungal Strain of the Orbital Complex Mir, Producing Xanthocyllin X and Questiomycin A

It was demonstrated that the fungus Penicillium expansum 2-7, a resident strain of the orbital complex Mir, which became dominant at the end of a long-term space flight, formed biologically active secondary metabolites (antibiotics). Using physicochemical methods these metabolites were identified as xanthocyllin X and questiomycin A. The time courses of their biosyntheses during the growth and development of the producer culture were studied. The addition of zinc to the culture medium affected both the growth of the culture and the biosyntheses of the antibiotics. The concentrations of zinc in the medium, optimum for xanthocyllin X and questiomycin A production, were 0.3 and 3.0 mg/l, respectively.     

The Fungus Penicillium citrinum Thom 1910 VKM FW-800 Isolated from Ancient Permafrost Sediments As a Producer of the Ergot Alkaloids Agroclavine-1 and Epoxyagroclavine-1

The study of the secondary metabolites of the relict strain Penicillium citrinum VKM FW-800 isolated from ancient Arctic permafrost sediments showed that this fungus produces agroclavine-1 and epoxyagroclavine-1, which are rare ergot alkaloids with the 5R,10S configuration of the tetracyclic ergoline ring system. The production of the alkaloids by the fungus showed a biphasic behavior, being intense in the phase of active growth and slowing down in the adaptive lag phase and in the stationary growth phase. The addition of zinc ions to the incubation medium led to a fivefold increase in the yield of the alkaloids. The alkaloid-producing Penicillium fungi isolated from different regions exhibited the same tendencies of growth and alkaloid production.     

New producers of biologically active compounds—fungal strains of the genus <Emphasis Type="Italic">Penicillium</Emphasis> isolated from permafrost

Screening of producers of secondary metabolites was carried out among 25 fungal strains of Penicillium genus isolated from permafrost in Arctic and Antarctic regions and Kamchatka. Nearly 50% of the investigated strains synthesize biologically active substances of alkaloid nature: ergot alkaloids, diketopiperazinees, and quinoline derivatives. A large group of the identified metabolites belongs to mycotoxins. A strain of Penicillium waksmanii was found producing epoxyagroclavine-I and quinocitrinines. The main physiological and biochemical characteristics of this producer were investigated.