Automated Food-Procuring Movement-Related Neuronal Activity in the Basolateral Amygdala of the Rat

We studied the impulse activity of neurons of the basal and lateral amygdalar nuclei generated when experimental animals (rats) performed fast stereotyped food-procuring movements by the forelimb. Within the basolateral amygdala, there are neurons whose activity is related to different stages of getting off the food, and according to the characteristics of their spiking these neurons should be divided into a number of subpopulations. Activation forestalling the movement initiation by 0.5-1.0 sec was observed in most neurons of the basolateral amygdala; this is considered a manifestation of excitation related to a motivation component of the food-procuring behavior. Activation of amygdalar neurons following movement initiation can result from generation in this structure of additional excitation necessary for successful performance of a complete food-procuring motor cycle.     

Multi-lineage Lung Regeneration by Stem Cell Transplantation across Major Genetic Barriers

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Mesocyclops longisetus effects on survivorship of Aedes aegypti immature stages in car tyres

Abstract .The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F.C.B. strain) on the survival of Aedes aegypti immature stages in car tyres was evaluated under semi-natural conditions in the municipality of Merida, Yucatan, Mexico. Life tables were constructed for the immature stages of the mosquito in the presence and absence of M. longisetus , and the survival data were compared using log–linear models. The data set was adjusted using the GLIM statistical package and the quality of adjustment was evaluated with a chi-squared test . Survivorship curves were constructed for each treatment.
In the absence of M. longisetus , the survivorship of Ae. aegypti immature stages averaged 9%. The highest mortality rate was observed during the fourth larval instar (54%) and the resulting survival pattern corresponded to a type II survivorship curve. The mortality rate of Ae. aegypti first-instar larvae (fifty per tyre) increased more than 200-fold in the presence of M. longisetus (twenty per tyre) and the highest mortality was during the first two larval instars, where it reached 98.9%, with a resulting survivorship of 0.2%. Overall mortality was sixfold greater in the presence of the copepod than in its absence. The survival pattern of immature stages of Ae. aegypti in the presence of the copepod corresponded to a type III survivorship curve. As M. longisetus was so effective against Ae. aegypti immature stages in tyres under semi-natural conditions, its long-term effectiveness should be evaluated under socially and ecologically realistic field conditions in Mexico.     

Maternal induction of larval diapause and its sensitive stage in the blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae)

Lucilia sericata has a facultative diapause in the third larval instar after cessation of feeding. Induction of the diapause is influenced by the photoperiod and temperature conditions experienced by insects in the parental generation as well as those experienced by the larvae themselves. The sensitive stage of the parental generation for induction of diapause was examined using diapause‐averting conditions of 16 h light : 8 h darkness (LD 16:8) at 25°C and diapause‐inducing conditions of LD 12:12 at 20°C. The incidence of diapause in the progeny was predominantly determined by the conditions experienced by the parents in the adult stage. Moreover, the results of reciprocal crosses showed that only the mother's experience is involved in the induction of diapause in the progeny.     

Thermal melting and circular dichroism of DNA complexes with (Lys-Ala-Ala)10 and (Lys-Ala-Ala)n: effect of polypeptide chain length

DNA complexes with polypeptides (Lys-Ala-Ala)₁)] and (Lys-Ala-Ala)₃₄ have been studied using the methods of thermal melting and circular dichroism. Derivative melting curves of (Lys-Ala-Ala)₁₀ DNA differed substantially from those of (Lys-Ala-Ala)₃₄ prepared either by salt gradient dialysis or by direct mixing. Melting curves of the former complex were unimodal or bimodal with T_m increasing continuously withn input lysin-to-DNA phosphate ratio (r); those of the latter complex consisted of three separate transitions with T_m values almost independent of r. Complete reversibility of binding in the (Lys-Ala-Ala)₁₀-DNA system but a slow redistribution of (Lys-Ala-Ala)₃₄ on DNA at low temperature were found in the redistribution experiments Much faster redistribution from denatured to native DNA occurs at the temperature of melting, contributing to the unusual trimodal melting pattern. Circular dichroism curves are very similar for both complexes and indicate little change of DNA conformation upon polypeptide binding.     

Transport protein synthesis in non-growing yeast cells

Addition of a metabolizable substrate (glucose, ethanol and, to a degree, trehalose) to non-growing baker's yeast cells causes a boost of protein synthesis, reaching maximum rate 20 min after addition of glucose and 40–50 min after ethanol or trehalose addition. The synthesis involves that of transport proteins for various solutes which appear in the following sequence: H⁺, l-proline, sulfate, l-leucine, phosphate, α-methyl-d-glucoside, 2-aminoisobutyrate. With the exception of the phosphate transport system, the K_t of the synthesized systems is the same as before stimulation. Glucose is usually the best stimulant, but ethanol matches it in the case of sulfate and exceeds it in the case of proline. This may be connected with ethanol's stimulating the synthesis of transport proteins both in mitochondria and in the cytosol while glucose acts on cytosolic synthesis alone. The stimulation is often repressed by ammonium ions (leucine, proline, sulfate, H⁺), by antimycin (proline, trehalose, sulfate, H⁺), by iodoacetamide (all systems tested), and by anaerobic preincubation (leucine, proline, trehalose, sulfate). It is practically absent in a respiration-deficient petite mutant, only little depressed in the op₁ mutant lacking ADP/ATP exchange in mitochondria, but totally suppressed (with the exception of transport of phosphate) in a low-phosphorus strain. The addition of glucose causes a drop in intracellular inorganic monophosphate by 30%, diphosphate by 45%, ATP by 70%, in total amino acids by nearly 50%, in transmembrane potential (absolute value) by about 50%, an increase of high-molecular-weight polyphosphate by 65%, of total cAMP by more than 100%, in the endogenous respiration rate by more than 100%, and a change of intracellular pH from 6.80 to 7.05. Ethanol caused practically no change in ATP, total amino acids, endogenous respiration, intracellular pH or transmembrane potential; a slight decrease in inorganic monophosphate and diphosphate and a sizeable increase in high-molecular-weight polyphosphate. The synthesis of the various transport proteins thus appears to draw its energy from different sources and with different susceptibility to inhibitors. It is much more stimulated in facultatively aerobic species (Saccharomyces cerevisiae, Endomyces magnusii) than in strictly aerobic ones (Rhodotorula glutinis, Candida parapsilosis) where an inhibition of transport activity is often observed after preincubation with metabolizable substrates.     

Application of a photosystem II model for analysis of fluorescence induction curves in the 100 ns to 10 s time domain after excitation with a saturating light pulse

A mathematical model of photosystem II (PSII) events was used to analyze chlorophyll fluorescence transients in the time domain from 100 ns to 10 s after excitation with a saturating 10-ns flash, applied as a part of specialized illumination protocol, using preparations of a thermophilic strain of the unicellular green alga, Chlorella pyrenoidosa Chick (using both intact and diuron-treated cells). Analysis of simulation results has proven that particular attention should be given to flash-induced recombination processes, including nonradiative recombination in PSII, while subsequent charge transfer along the electron transport chain of thylakoid membrane can be adequately described by a single reaction of quinone reoxidation. The PSII model was extended by taking inhibition by diuron of the electron transport in the acceptor side of PSII into account, which allowed simulation of fluorescence induction curves observed in the presence of this inhibitor. The model parameters were determined (stromal pH, rate constants of nonradiative recombination, and the initial reduction state of the quinone pool) which provided adequate simulation of experimentally observed ratios of the maximal and initial fluorescence levels (F _m/F ₀).     

Abundance of mRNAs encoding HMG1/HMG2 class high-mobility-group DNA-binding proteins are differentially regulated in cotyledons of Pharbitis nil

The abundance of an mRNA encoding an HMG1/2 protein from Pharbitis nil (HMG1) has been previously shown to be regulated by light and an endogenous rhythm in cotyledons. A second Pharbitis nil HMG cDNA (HMG2) was characterized. The sequence of HMG2 was 82% and 86% identical to HMG1 at the nucleotide and amino acid level, respectively. As with HMG1, HMG2 mRNA was detected in all vegetative tissues and was most abundant in roots. However, unlike HMG1, HMG2 mRNA abundance did not increase upon transfer of cotyledons to darkness and did not exhibit regulation by an endogenous circadian rhythm when maintained in continuous darkness over a 68 h period. Similarly, while the abundance of HMG1 mRNA during a dark period that induced photoperiodically controlled flowering was dramatically affected by brief light exposure (night break), this treatment had no effect on HMG2 mRNA abundance. Collectively, these data are consistent with a role of HMG1 in contributing to the circadian-regulated and/or dark-regulated gene expression with constitutive expression of HMG2 playing a housekeeping role in the general regulation of gene expression in Pharbitis nil cotyledons.