Aggressive Behavior Evoked by Radio Stimulation in Monkey Colonies

Macaca mulatta with multilead electrodes permanently implantedin the brain were electrically stimulated, either under restraint,or by radio while moving freely as part of a colony, in whichcase individual and social behavior were recorded, analyzed,and quantified with the aid of time-lapse photography. Somecerebral radio stimulations evoked complex sequences of wellorganized responses. Increase in running and in offensive behaviorwas produced by excitation of midline thalamus, while even fasterrunning without changes in aggressiveness was produced by stimulationof the fimbria of the fornix. Conditioning was absent in thefirst case, but it was easily established in the latter. Increasein aggressive behavior was also produced by stimulation of Forel'sfield, the nucleus ventralis posterior lateralis of the thalamus,and the central gray matter. Increase in aggressiveness wasoriented by the animal according to past experience, likes anddislikes, and was adapted to the changing strategies of itsopponent, indicating an excellent processing of sensory information,and demonstrating that brain stimulation had induced a "drive"and not a stereotyped motor response. As a working hypothesis it is proposed that cerebral mechanismsfor perception of pain and for aggressive behavior have differentanatomical and physiological systems closely interrelated byuse, disuse, and conditioning.     

Impact of habitat fragmentation on the genetics of populations in dendritic landscapes

1. The effect of habitat fragmentation on freshwater species has been addressed using brown trout Salmo trutta L. as a model species with a dendritic population structure. 2. Microsatellite loci were employed as molecular markers. Levels of gene flow and population subdivision were determined in more than 1200 brown trout individuals inhabiting four south European rivers with contrasting patterns of fragmentation, defined by the presence of barriers. 3. The genetic units in the four rivers were restricted by artificial barriers, and gene flow among samples within each river was associated with the level of fragmentation of the river. 4. Loss of genetic diversity and dislocation of the dendritic model have been detected in fragmented rivers. These results emphasise the importance of mitigating the impact of dams by constructing passages to restore gene flow along the river, for fish and other migratory species, as well as the need for caution in relation to stocking in isolated areas to avoid problems of inbreeding.     

Serum Proteins Promoting [3H]Thymidine Uptake by Trypanosoma (Schizotrypanum) cruzi (Chagas) in vitro

SYNOPSIS. Five proteins capable of stimulating [³H]thymidine uptake by Trypanosoma cruzi in vitro were isolated from fetal calf serum by (NH₄)₂SO₄ precipitation and ion exchange column chromatography. The proteins were partially characterized by immunodiffusion, immunoelectrophoresis, polyacrylamide gel disc electrophoresis, and SDS electrophoresis. As estimated by SDS electrophoresis, using 4 standards, the molecular weight of protein 1 was 100,000, that of protein 2 was 76,000. and that of proteins 3–5 was 68,000 daltons.     

Coral successions in Upper Tortonian reefs in SE Spain

Martin, Jose M., Braga, Juan C. & Rivas, Pascual 1989 07 15: Coral successions in Upper Tortonian reefs in SE Spain. Lethaia , Vol. 22, pp. 271–286. oslo. ISSN 0024–1164,
During the Upper Tortonian (Upper Miocene), the Almanzora river corridor, a small Neogene basin in SE Spain, harboured coral reefs growing in three different environments: in fan deltas, beyond the influence of coarse terrigenous sedimentation; in the abandoned lobes of a delta complex; and on coastal margins. All of these reefs are composed of several successive beds, each of which may be made up mainly of Porites embedded in silt or of an initial Porites level followed by a silt-free Tarbellastraea level on top. Porites may be associated with corallines. This structure is interpreted as being the result of an ecological succession repeated over and over again. A pioneer association consisting mainly of Porites . by colonizing the substrate and continuing to grow through relatively adverse silt-deposition conditions, prepares the ground for Tarbellastraea to take over. A return to the previous conditions halts the growth of the Tarbellastraea colonies and the Porites association once more establishes itself in the silt, or else the renewed rate of deposition is sufficiently heavy to suffocate the whole bioconstruction.* Ecological succession. coral reefs, Tortonian, southeast Spain .     

A New Liquid Medium for Trypanosoma (Schizotrypanum) cruzi*

A new liquid medium, with fetal calf serum as the sole undefined component, was devised for the cultivation of Trypanosoma cruzi. The need for the serum is ascribed to its mitogenic proteins, which stimulate division of, and the uptake of [³H]thymidine by the parasites. In the new medium, T. cruzi has a cycle culminating in the appearance of up to 90% metacyclic forms in the stationary phase. This cycle is repeated on each serial transfer.     

Observations on Bacterial Feeding by the Rumen Ciliate Isotricha prostoma

SYNOPSIS. Starvation of Isotricha prostoma for 72–96 hours decreased the cellular amylopectin granules and facilitated the microscopic search for bacterial feeding. I. prostoma selected and ingested only certain rods from among many types of rumen bacteria. In order to isolate the bacteria important as a food source for Isotricha , the starved protozoa were allowed to feed on mixed rumen bacteria, washed, and the crushed protozoan contents quickly cultured for bacteria. Several strains of bacteria were isolated in pure culture. Three of the rod strains isolated were rapidly ingested by I. prostoma when fed to the ciliate. In a monobacterial culture I. prostoma divided once before succumbing.     

Multi‐gene phylogeny of the Hemileuca maia complex (Saturniidae) across North America suggests complex phylogeography and rapid ecological diversification

The Hemileuca maia species complex occurs across the North American continent and consists of six named taxa, and several others that were recently synonymized. Taxa exhibit a wide span of adult flight periods, dramatic shifts in host‐plant use and occur in a range of habitats, all of which would suggest unrecognized diversity. We used one mitochondrial and three nuclear genes to generate 3900 bp per individual, including samples from every ecotype in the species group across the United States from New England to central Florida to California. We assessed phylogenetic relationships using both maximum likelihood and Bayesian phylogenetic methods. Results suggest very low levels of divergence across most of the continent and low levels of genetic structure – even between some recognized species that maintain clear ecological difference in sympatry. Our results suggest that meaningful and localized ecological divergence may occur in the absence of easily recognizable genetic divergence, due to either ongoing gene flow or the recent diversification in the group.     

A new Spanish species of Linaria Miller (Scrophulariaceae)

Linaria arabiniana sp. nov. is described from coastal sand dunes of a very reduced area in Alicante Province (south-eastern part of the Iberian Peninsula). It is a perennial herb characterized by its 3–4-verticillate leaves, glabrous stems, large violet or rarely yellow flowers, and bicoloured usually flat seeds. Morphological characteristics and taxonomic affinities of this taxon are discussed, as are data on its ecology, phytosociology, and eventual conservation features.