Comparative effectiveness of light-microscopic techniques and PCR in detecting Thelohania solenopsae (Microsporidia) infections in red imported fire ants (Solenopsis invicta)

The main goal of this study was to compare the effectiveness of three staining techniques (calcofluor white M2R, Giemsa and modified trichrome), and the polymerase chain reaction (PCR) in detecting the microsporidium Thelohania solenopsae in red imported fire ants (Solenopsis invicta). The effect of the number of ants in a sample on the sensitivity of the staining techniques and the PCR, and the effect of three DNA extraction protocols on the sensitivity of PCR were also examined. In the first protocol, the ants were macerated and the crude homogenate was used immediately in the PCR. In the second protocol, the homogenate was placed on a special membrane (FTA card) that traps DNA, which is subsequently used in the PCR. In the third protocol, the DNA was purified from the homogenate by traditional phenol-chloroform extraction. Except for PCR using FTA cards, the sensitivity (number of samples positive for T. solenopsae) of all detection techniques increased with the number of ants in the sample. Overall, Giemsa was the least sensitive of all detection techniques. Calcofluor was more sensitive than modified trichrome with ants from one site and was equally as sensitive as PCR with crude DNA or a FTA card with ants from both sites. Trichrome staining was equally as sensitive as PCR with a FTA card at both sites, but it was less sensitive than PCR with crude DNA at one site. PCR on FTA cards was less sensitive than PCR with crude DNA for ants from one site but not the other. There was no difference whether crude or phenol-chloroform purified DNA was used as template. In summary, the results of this study show that PCR based on a crude DNA solution is equal to or more sensitive in detecting T. solenopsae than the other detection techniques investigated, and that it can be used as a reliable diagnostic tool for screening field samples of S. invicta for T. solenopsae. Nevertheless, ant smear stained with calcofluor or modified trichrome should be used to buttress findings from PCR.     

Selection of a mixed culture of cellulosolytic thermophilic anaerobes from various natural sources

Microbial associations capable of converting cellulose-containing substrates to ethanol and organic acids were isolated from natural sources. The resulting mixed cultures utilized cellulose, cellobiose, glucose, maize residue, cotton, and flax boon producing ethanol (up to 0.9 g/l) and acetic acid (up to 0.8 g/l). The most complete conversion of cellulose-containing substrates occurred at 60 degrees C, pH 7.0. The selected association of thermophilic anaerobic bacteria produced 0.64 g ethanol per g substrate utilized at the ethanol/acetate ratio 4.7:1.     

Structural and functional aspects of the nucleolar organizing region of interphase cell nuclei during hemoblastosis

Data on concept of the nucleolar-organizing regions of the human somatic cell interphase nuclei, methods of their revealing, classifications, as well as their structural-functional peculiarities in norm and under different diseases of blood system, in particular under hemoblastosis, are reviewed in historical aspect.     

The lifespan of the cladoceran Ceriodaphnia affinis Lilljeborg in a laboratory culture

The lifespan of the cladoceran Ceriodaphnia affinis Lilljeborg in a laboratory culture has been determined. The lifespan decreases in June and from November to December and it increases from February to March and from August to September. Minor changes in temperature over the year (21±3°C) have no direct effect on the lifespan of the animals. The average lifespan proves to be a more variable parameter than the maximum lifespan.     

Stimulation of life processes in Ceriodaphnia affinis Lilljeborg (Crustacea,Anomopoda) at low concentrations of potentially toxic substances

The effects of ethanol, potassium chloride, and potassium dichromate on the lifespan and fecundity of cladoceran Ceriodaphnia affinis have been studied experimentally. The average lifespan and female fecundity increase at ethanol concentrations of 0.002 mg/L and 0.02 mg/L and at a potassium chloride concentration of 0.1 mg/L. Only a concentration of 0.0001 mg Cr/L increased the lifespan of the cladocerans by 108% in comparison with the control condition within a wide spectrum of tested concentrations of this agent. The reason for such a phenomenon is discussed, as is its ecological role.     

Modification of olivomycin A at the side chain of the aglycon yields the derivative with perspective antitumor characteristics

A novel way of chemical modification of the antibiotic olivomycin A (1) at the side chain of the aglycon moiety was developed. Interaction of olivomycin A with the sodium periodate produced the key acid derivative olivomycin SA (2) in 86% yield. This acid was used in the reactions with different amines in the presence of benzotriazol-1-yl-oxy-trispyrrolidino-phosphonium hexafluorophosphate (PyBOP) or diphenylphosphoryl azide (DPPA) to give corresponding amides. Whereas olivomycin SA was two orders of magnitude less cytotoxic than the parent antibiotic, the amides of 2 demonstrated a higher cytotoxicity. In particular, N,N-dimethylaminoethylamide of olivomycin SA showed a pronounced antitumor effect against transplanted experimental lymphoma and melanoma and a remarkably high binding constant to double stranded DNA. The therapeutic effects of this derivative were achievable at tolerable concentrations, suggesting that modifications of the aglycon’s side chain, namely, its shortening to methoxyacetic residue and blocking of free carboxyl group, are straightforward for the design of therapeutically applicable derivatives of olivomycin A.     

Three twinning types in mink (Mustela vison) embryogeny

The frequency of emergence of monochorial twins in the postimplantational embryogeny of the American mink and their karyotypes were studied. Monochorial pairs were found in which embryos had different karyotypes: 2n, XX and 2n, XY or 2n and 3n. This fact contradicts the notion that monochorial twins should be monozygotic and genetically identical but confirms our earlier hypothesis that a third twinning type exists in mink: monozygotic but genetically different. The mechanism of the emergence of this twinning type in mammals is discussed. It is suggested that the high (up to 4.5%) frequency of its emergence in the American mink is related to obligate embryonic diapause, causing abnormal fertilization.     

Three twinning types in mink (<Emphasis Type="Italic">Mustela vison</Emphasis>) embryogenesis

The frequency of occurrence of monochorionic twins in the postimplantational embryogenesis of the American mink and their karyotypes were studied. Monochorionic twin pairs were found in which embryos had different chromosome sets: 2n, XX and 2n, XY or 2n and 3n. This fact contradicts the idea that monochorionic twins should be monozygotic and genetically identical but confirms our earlier hypothesis that a third twinning type exists in mink: monozygotic but genetically different. The mechanism of the emergence of this twinning type in mammals is discussed. It is suggested that the high (up to 4.5%) frequency of its emergence in the American mink is related to obligate embryonic diapause, causing abnormal fertilization.