Behavioral mechanisms of spatial competition between red wood ants (Formica aquilonia) and ground beetles (Carabidae)

Behavioral aspects of spatial competition between red wood ants (Formica aquilonia) and six mass species of Carabidae were studied in field and laboratory experiments. We showed that red wood ants essentially influence spatial distribution of ground beetles on their common territories. Transplantation experiments suggest that in newly established ants' settlements stronger forms of interrelations arise than in old stable colony. To examine the ability of beetles to avoid collisions with ants we used two experimental techniques. In laboratory, we tested carabids ability to avoid a clash in a Y-shaped labyrinth containing an active tethered ant in one section. In field experiments we compared quantitative characteristics of movements (such as crookedness of individual trajectories, speed of movement, the time spent on stops) for beetles placed close to ants foraging routes and on ant-free plots. All beetles studied displayed a clear tendency to learn, that is, to modity their behavior in order to avoid collisions with ants. Species that exhibited best parameters of learning were closer to ants by their size and characteristic movement, namely, Pterostichus oblogopunctatus and P. magus. Beetles' stereotyped behavioral tactics can be considered universal for avoiding collisions with any subject (for instance, with an ant) of a certain size and speed of movements. A set of tactics in the labyrinth included: (1) attempts to round the ant; (2) turns away after touching the ant with antennae; (3) turns away without a contact; (4) avoidances of a dangerous section; (5) stops near the ant with the antennae hidden. Comparing pairwise difference between four species shows that beetles use species-specific preference for definite combinations of tactics. Effective learning allows carabids to penetrate into ant foraging territory and partly avoide interference competition. It seems that red wood ants are not inclined to learn to avoid collisions with competing carabid species. Instead, they recognize an "enemy's image" and selectively attack relatively small predatory carabids rather than herbivorous species. Experiments with dummy beetles suggest that ants react for several hierarchically organized key characteristics of competitors such as speed of movement, dark color, bilateral symmetry, protuberances (legs, antennae), and smell. Among "professional" groups in ant family, guards and hunters react to beetles aggressively, whereas aphid tenders ignore them. Sophisticated combination of flexible and innate behavioral patterns enables insects to share territories and interact in the mode of relatively mild, spatial, competition instead of predation. Eliciting sets of hierarchically organized features of competitors that govern adjustment of spatial distribution in insects' community enable us to integrate ideas of classic and cognitive ethology.     

Imaging of Metastatic Lymph Nodes by X-ray Phase-Contrast Micro-Tomography

Invasive cancer causes a change in density in the affected tissue, which can be visualized by x-ray phase-contrast tomography. However, the diagnostic value of this method has so far not been investigated in detail. Therefore, the purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients. Seventeen formalin-fixed paraffin-embedded lymph nodes from 10 female patients (age range 37–83 years) diagnosed with invasive ductal carcinomas were analyzed by X-ray phase-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study was that the diagnostic sensitivity of the image analysis for detecting malignancy was 100% and the specificity was 87%. The positive predictive value was 91% for detecting malignancy and the negative predictive value was 100%. We conclude that x-ray phase-contrast imaging can accurately detect density variations to obtain information regarding lymph node involvement previously inaccessible with standard absorption x-ray imaging.     

Suppression of DNA synthesis in mice by the anthracycline antibiotics daunorubicin, carminomycin and doxorubicin

Inhibition of DNA synthesis by rubomycin (daunorubicin), carminomycin and doxorubicin in the spleen, liver, kidneys and heart was studied on mice. The antibiotics were administered intravenously in a dose of 0.3 LD50. The inhibition level was estimated by incorporation of 3H-thymidine. The time courses of DNA synthesis inhibition by daunorubicin, carminomycin and doxorubicin markedly differed, whereas the patterns of their inhibition curves for all the organs were close. The maximum inhibition of DNA synthesis by carminomycin was observed in 6 hours. After that period it gradually restored. Doxorubicin induced the maximum inhibition of DNA synthesis in 24-48 hours after its administration. Daunorubicin induced two maxima in inhibition of DNA synthesis i. e. in 6 and 48 hours. Definite correlation between the levels of DNA synthesis inhibition by the antibiotics and their toxic action was shown.     

Experimental studies of the capacity of ants for the addition and subtraction of small numbers]

In the laboratory experiments Formica polyctena ants had to transmit the information about the position of a "branch" situated on a long "trunk". Each branch ended in an empty trough, save one filled with syrup. The food was placed on different branches with different frequencies; on the preliminary chosen special branches the troughs were filled substantially more frequently than on the others. For example, in 1993 we chose two special branches, nos. 10 and 20, on which the food was placed with a probability of 1/3, while for any of the other 28 branches the probability was 1/84. When the ants had learnt this, they changed the way of information transmission about the coordinates of the branch containing food and spent less time to transmit the messages about branches nos. 10 or 20. Careful analysis of time required for transmitting messages about trough coordinates suggests that ants "present" the number of a branch in a way similar to that for the Roman figures, and the "special" numbers (10 and 20 in the case) have the same significance as the basic Roman figures V, X, L, etc. Thus, the ants seem to be able, first, to put the duration of a message into agreement with its frequency and, second, to add and subtract small numbers, as people do when use the Roman figures.     

The interaction of per-O-acetylated acyclic 1-(1-butylindol-3-yl)-1-deoxy-ketoses with silylated uracil

The per-O-acetylated open chain derivatives of 1-(1-butylindol-3-yl)-1-deoxy-1-L-sorbose and 1-(1-butylindol-3-yl)-1-deoxy-L-tagatose, which are readily available by alkaline degradation of 1-butylascorbigen followed by acetylation, were used in a nucleoside-type synthesis. The interaction of these ketoses derivatives with bis-(trimethylsilyl)-uracil yielded in each case a mixture of (E)-2,4,5,6-tetra-O-acetyl-1-(1-butylindol-3-yl)-1,3-dideoxy-3-(uracil-1-yl)-L-xylo-hexa-1-enitol and (E)-2,4,5,6-tetra-O-acetyl-1-(1-butylindol-3-yl)-1,3-dideoxy-3-(uracil-1-yl)-L-lyxo-hexa-1-enitol, which were separated by preparative HPLC. The deacetylation of each of these compounds by MeONa in MeOH produced a mixture of 1-(1-butylindol-3-yl)-1,3-dideoxy-4-O-methyl-3-(uracil-1-yl)-alpha-L-sorbopyranose and 1-(1-butylindol-3-yl)-1,3-dideoxy-4-O-methyl-3-(uracil-1-yl)-beta-D-fructopyranose, which were also separated by HPLC, the structures were confirmed by NMR.     

New antibiotics produced by Bacillus subtilis strains

Two Bacillus subtilis strains isolated from the fruiting body of a basidiomycete fungus Pholiota squarrosa exhibited a broad range of antibacterial activity, including those against methicillin-resistant Staphylococcus aureus INA 00761 (MRSA) and Leuconostoc mesenteroides VKPM B-4177 resistant to glycopeptide antibiotics, as well as antifungal activity. The strains were identified as belonging to the “B. subtilis” complex based on their morphological and physiological characteristics, as well as by sequencing the 16S rRNA gene fragments. Both strains (INA 01085 and INA 01086) produced insignificant amounts of polyene antibiotics (hexaene and pentaene, respectively). Strain INA 01086 also produced a cyclic polypeptide antibiotic containing Asp, Gly, Leu, Pro, Tyr, Thr, Trp, and Phe, while the antibiotic of strain INA 01085 contained, apart from these, two unidentified nonproteinaceous amino acids. Both polypeptide antibiotics were new compounds efficient against gram-positive bacteria and able to override the natural bacterial antibiotic resistance.     

Increased sensitivity of the fatty tissue of rats with spontaneous hypertension to the action of ACTH. The role of calcium]

The action of ACTH on the adipose tissue lypolysis was studied in rats with spontaneous and renal hypertension as well as in normotensive rats of the respective control groups. It was demonstrated that sensitivity of the adipose tissue SHR to ACTH was increased as compared to normotensive controls. The data presented indicate that the increased sensitivity is due to the state or content of intracellular calcium. The rats with renal hypertension did not show such an increased sensitivity of the adipose tissue to ACTH.