Resistance to glufosinate is proportional to phosphinothricin acetyltransferase expression and activity in LibertyLink® and WideStrike® cotton

Planta - Insertion of the gene encoding phosphinothricin acetyltransferase (PAT) has resulted in cotton plants resistant to the herbicide glufosinate. However, the lower expression and commensurate...     

Dynamics of the integrated characteristics of heart rate variability and psychophysiological parameters of students under the conditions of daily and weekly academic loads

The effects of daily and weekly academic loads on the psychological and cardio-and hemodynamic characteristics of students were analyzed. The self-estimated state of health, activity, and mood were evaluated with the use of the HAM (Health-Activity-Mood) questionnaire; the introversion and extraversion, neuroticism, and intelligence of the subjects were determined according to Eysenck; and the self-estimate the personal anxiety according to Spielberger, was evaluated. The main hemodynamic parameters (heart rate and arterial blood pressure) were measured and the systolic and minute blood volumes were calculated. The comparison of the dynamics of the parameters studied showed that there were two types of response of the students’ cardio-and hemodynamic parameters to academic load: sympathetic and parasympathetic. The parasympathetic response was found to be more adequate because the sympathetic response entailed the risk of overstrain and adaptation failure.     

Ecological and community-wide character displacement: the next generation

Ecological character displacement, mostly seen as increased differences of size in sympatry between closely‐related or similar species, is a focal hypothesis assuming that species too similar to one another could not coexist without diverging, owing to interspecific competition. Thus, ecological character displacement and community‐wide character displacement (overdispersion in size of potential competitors within ecological guilds) were at the heart of the debate regarding the role of competition in structuring ecological communities. The debate has focused on the evidence presented in earlier studies and generated a new generation of rigorous, critical studies of communities. Character displacement research in the past two decades provides sound statistical support for the hypothesis in a wide variety of taxa, albeit with a phylogenetically skewed representation. A growing number of studies are strongly based in functional morphology, and some also demonstrate actual morphologically related resource partitioning. Phylogenetic models and experimental work have added to the scope and depth of earlier research, as have theoretical studies. However, many challenging ecological and evolutionary issues, regarding both selective forces (at the inter‐ and intraspecific level) and resultant patterns, remain to be addressed. Ecological character displacement and community‐wide character displacement are here to stay as the focus of much exciting research.     

An altered peptide ligand inhibits the activities of matrix metalloproteinase-9 and phospholipase C, and inhibits T cell interactions with VCAM-1 induced in vivo by a myasthenogenic T cell epitope.

Myasthenia gravis (MG) is a T cell-regulated, antibody-mediated autoimmune disease. Immunization with two myasthenogenic peptides, p195-212 and p259-271, which are sequences of the human acetylcholine receptor, resulted in MG-associated immune responses. A dual altered peptide ligand (APL) composed of the two APLs of the myasthenogenic peptides inhibited, in vitro and in vivo, those responses. This study was aimed at understanding the mechanism(s) underlying the in vivo inhibitory properties of the dual APL. To this end, we analyzed T cells of mice that were immunized with p259-271 for their adhesiveness toward vascular cell adhesion molecule 1, for the activity of their secreted matrix metalloproteinases (MMPs), and for their intracellular phospholipase C (PLC) activity. Immunization with p259-271 triggered the above three activities and in vivo administration of the dual APL inhibited the latter. Thus, treatment of mice with the dual APL interferes with functions required for T cells to migrate and interact with the self-AChR. This is the first indication that very late antigen 4, MMP-9, and PLC are targets for immunomodulation of autoreactive T cells by altered peptide ligands.     

Prostacyclin (PGI2) effets on anterior pituitary hormones in the rat in vivo

Intravenous injection of 600 μg PGE₂ or PGI₂ significantly increased serum LH and prolactin levels in estradiol treated ovariectomized rats. There was no effect on serum FSH concentration. PGE₂ and PGI₂ stimulated LH release in a non-dose dependent manner, while prolactin levels were positively correlated with the dose administered following PGI₂ treatment. 6-keto-PGF_1α at a comparable dose had no effect on pituitary hormone levels. Subcutaneous administration of 1 mg/kg or 60 mg/kg PGI₂ for seven days significantly depressed serum LH level both in male and female rats. These doses had no effect on serum FSH or prolactin levels.     

Interspecific displacement mechanisms by the invasive little fire ant <Emphasis Type="Italic">Wasmannia auropunctata</Emphasis>

Competition between invasive species and native ones in the new environment was found to be significant and to affect both animal and plant species. Invasive ants are notorious for displacing local ant species through competition. Competitive displacement of native species can occur through interference and or resource competition. However, for invasive ants, little is known about the relative importance of competitive displacement. We studied competitive interactions of the little fire ant, Wasmannia auropunctata, one of the most destructive invasive ant species, with two other ant species, Monomorium subopacum and Pheidole teneriffana. We compared the species’ foraging behavior and studied their aggressive interactions around food baits for the short (2 h) and long (21 days) term in the laboratory. Surprisingly we found that in short term experiments W. auropunctata had the poorest foraging abilities of the three species studied: it took the workers the longest to locate the bait and retrieve it; in addition they retrieved the lowest amount of food. When both W. auropunctata and M. subopacum were foraging the same bait, in the short term competition experiment, W. auropunctata workers did not defend the bait, and ceased foraging when encountered with competition. The long-term experiments revealed that W. auropunctata had the advantage in aggressive interactions over time; they eliminated seven of nine M. subopacum’s nests while consuming some of the workers and brood. According to our laboratory studies, W. auropunctata cannot be considered an extirpator species, unless it has a substantial numerical advantage, in contrast with previous assumptions. Otherwise it may behave as an insinuator species, i.e. the workers do not initiate aggression and by staying undetected they can continue foraging adjacent to dominant species.     

Structure of adenovirus fibre. II. Morphology of single fibres

Adenovirus type 2 fibres in crystals appear to be significantly longer than found previously (accompanying paper). We therefore examined isolated fibre by electron microscopy and measured a length of 370 A, consistent with the length found in the crystals. The specific N-terminal structure of the fibre caused a heterogeneity in the length that may at least partially explain the values of 280 to 310 A published previously. Green et al. described a 15 amino acid repeat in the primary structure of the shaft of the fibre thought to be associated with the specific three-dimensional folding of the shaft. We compared the adenovirus type 2 (with 22 repeats) and type 3 (with 6 repeats) fibre lengths and derived a contribution of 13.2 A to the length of the shaft per 15 amino acid repeat. Specific morphological features of the fibre are discussed in relation to its amino acid sequence.