Relation between the defensive behavior of altricial nestlings and the parameters of an alarm signal. Neuroethologic approach

The acoustic organization of the defensive behaviour was studied in Pied Flycatcher nestlings. Electrodes were chronically implanted into the field L and the neck muscles for auditory EPs and EMG recordings. A well developed defensive reaction which under natural conditions is elicited by species-specific alarm call, could be artificially provoked by monotonal 4.5-6 kHz bursts with repetition frequency of 4-0,8/s. The tone frequency was shown to be the critical acoustic parameter permitting the altricial nestlings to identify alarm vocalization and differentiate it from alimentary signals. The role of the burst repetition frequency is restricted to maintaining the tonic defensive activation in the course of the alarm signal presentation. Certain correlation was found between the time of regeneration of excitability in auditory structures and the burst repetition frequency in the species specific alarm signal.     

Changes in the lymphoid cells of DNA and purine nucleotide synthesis and sensitivity to glucocorticoids associated with impairment of differentiation and immune function during tumor growth in mice. Thymocytes

Some biochemical mechanisms underlying the impairments of cellular immunity were studied in C3Ha mice in the course of growth of transplantable and induced (ortoaminoazotoluol) solid hepatomas. During intensive hepatoma growth, the adenosine deaminase activity in host thymocytes was shown to be drastically (6 times) reduced, resulting in the elevation of dATP and dGTP concentrations (6- and 7-fold, respectively), the potential inhibitors of ribonucleoside diphosphate reductase. Consequently, the rate of DNA synthesis was reduced as can be evidenced by the decrease of (a) thymidine kinase activity, (b) 14C-thymidine incorporation into DNA, and (c) dTTP and dCTP pools. By the terminal period of hepatoma growth (both transplantable and induced one), the serum corticosterone content increased 3- and 8-fold, respectively. At the same time, specific binding of [3H]triamsinolone acetonide by thymocytes was augmented and the activity of terminal deoxynucleotidyl transferase increased the latter alterations, which can be regarded as a reflection (including other parameters mentioned) of the arrest of T-lymphocyte differentiation at the level of immature cortex thymocytes.     

Induced Resistance in Tomato Against Corynebacterium michiganense pv. michiganense by Prior Inoculation with Pseudomonas syringae Pathovars

Prior inoculation of wounded tomato petioles with a minimum concentration of 5 × 10⁴ cells per wound of various Pseudomonas syringae pathovars completely protected plants against subsequent infection with Corynebacterium michiganense pv. michiganense inoculated on the same site. Only living cells induced effective protection. In protected tissue, cells of Corynebacterium michiganense pv. michiganense remained localized at the inoculation site and their multiplication was restricted. Irrespective of the cell number introduced, initial population decreased slowly and then levelled off below the initial inoculum level. This level remained constant throughout the experimental period (15 days). Similarly, the, cell number of the inducer Pseudomonas syringae pv. phaseolicola levelled off at ca. 10⁶ cells per plant. The protection was not systemic and could be eliminated by removing the upper 5 mm of the inoculated wound tissues containing, the inducer.     

Reaction between dexamethasone-receptor complexes and isolated nuclei from Zajdela hepatoma and rat liver cells]

Temperature-activation of the hormone-receptor complex (HRC) was shown to be necessary to ensure its translocation from cytoplasm to nucleus both in the rat liver and hepatoma. Hepatoma nuclei bind 20 times less HRC derived from homologous hepatoma cytosol (0.15 pmol/mg DNA), but twice as much (5.6 pmol/mg DNA) of HRC from heterologous liver cytosol, as compared with the binding of HRC from normal liver cytosol by liver nuclei (3 pmol/mg DNA), Ka of HRC with the acceptor sites in hepatoma and liver nuclei were found to be practically of the same order of magnitude. The above findings suggest an inhibition of cytosol-nucleus translocation of HRC from the cytosol of hepatoma cells as a possible cause of the nonresponsiveness of the latter to the hormone.     

Effects of aldicarb persistence on field populations of Heterodera schachtii

In field trials in 1976 and 1977 various granular formulations of aldicarb (2–8 to 12.8 kg a.i. ha^-1) were applied to sugar-beet fields infested with Heterodera schachtii . The levels of toxic residues of aldicarb and of H. schachtii populations in the soil were monitored at intervals throughout the sugar-beet season.
A severe drought in 1976 seriously affected the field trials and although aldicarb levels were maintained in the soil no aldicarb treatment proved effective in controlling H. schachtii; this was probably due to lack of mobility of the pesticide in the soil. In 1977, the final nematode populations in plots treated with 2.8 or 11.2 kg a.i. ha^-1 added incrementally through the growing season to simulate the effect of a controlled release formulation were not significantly different from those of untreated plots. In contrast treatment at drilling with fast-releasing formulations at all application rates did promote control of H. schachtii populations. No significant increase in yield was found on any trial after treatment with aldicarb.
The value of controlled release formulations of aldicarb for the control of H. schachtii populations over the growing season has not been proven.