Palaeocommunity Dynamics and Behavioral Analysis of Conichnus: Bhuj Formation (Lower Cretaceous),Kachchh-India

A palaeocommunity of large Conichnus conicus, a conical, cone-in-cone shaped burrow, created by sea anemones, occurs in medium-grained, crossbedded, well-sorted sandstone in the middle part of the Cretaceous Guneri Member of the Bhuj Formation in India. The trace fossil Conichnus is considered to be a common element of the Skolithos ichnofacies and is interpreted to reflect equilibrium movement in response to substrate aggradation. In the present study, three different varieties of Conichnus conicus are distinguished based on morphology and internal fabric. Community dynamics and burrowing behavior are revealed by inter-burrow relationships, burrow initiation levels and sedimentology. Three types of behavior are envisaged: retrusive equilibrium, protrusive equilibrium response, and escape behavior. Palaeocommunity dynamics show that the tracemakers consisted of only adult organisms that initiated burrows during neap tides and are adapted to feed effectively during weak flow conditions. The occurrence of Conichnus palaeocommunity in the Guneri Member indicates the tidal conditions in a fully marine setting. Results presented herein may aid in the understanding of palaeocommunity dynamics in other shallow marine sequences.     

Lack of prominent compensatory polycythemia in traditional native Andeans living at 4,200 meters

Red blood cell count (RBC), hemoglobin concentration ([Hb]) and hematocrit (Hct) were measured in 303 male Quechua children and adults, aged 6 to 57 years, living a lifestyle as traditional pastoralists and horticulturalists at a mean altitude of 4,200 m in the Southern Peruvian Andes. Values for RBC, [Hb], and Hct increased with age from middle childhood to young adulthood. However, among adults there was no significant association between age and any of these three parameters. Overall, there was approximately a 10-12% increase in the RBC, [Hb], and Hct above sea-level norms for all age groups. Mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) showed a slight but significant increase with age in children and adolescents, but the mean corpuscular hemoglobin concentration (MCHC) did not. We conclude that the study of highland Quechua Indians, living a traditional lifestyle as pastoralists and horticulturalists, does not support the long-held belief that altitude hypoxia provokes a dramatic compensatory polycythemia in healthy Andeans.     

Inducing sporulation in Alternaria solani II. Effect of light

Among the three different light sources viz. incandescent electric light, infra-red light and sunlight, only sunlight was effective in inducing sporulation in petri dish cultures ofA. solani. The intensity of sporulation depended upon the age and growth stage of the cultures, duration and number of exposures to light and the presence or absence of a sporulating zone in the culture. Maximum sporulation was obtained in the case of 6 days old partially grown cultures by inducing the formation of sporulating zone which appeared in 24 hours after every exposure of 60 minutes to sunlight.     

Abnormalities in the fine structure of the spermatids of rats injected with cadmium

The degenerative changes in the spermatids as measured by changes in fine structure abnormalities increased with time following injection of Cd²⁺ into rat testis. The spermatids in the twelve hours group appear as peculiarly club shaped and elongated structures with one or two small but perceptible vacuoles. The subacrosomal area and the space between the nucleus and the middle piece are seen abnormally dilated. In the 30 day group, the central filaments are the most susceptible unit of 9+2 axoneme complex. The plasma membrane, the cytoplasmic matrix, the mitochondria of the middle piece and the fibrous sheath appear shrunken, discontinuous and degenerative.     

Prolactin secreting cells in the hypophysis of the brown spiny mouseMus platythrix (Bennett)

Prolactin secreting cells are identified in thepars distalis of Mus platythrix by conventional methods of light and electron microscopy. Two types of prolactin secreting cells are recognised. These types are estrone-sensitive, mammotrophic type I, and luteotrophic type II, respectively. Histochemical analysis revealed that the cells are rich in RNA, basic proteins, alkaline phosphatase and are resistant to extraction with 0·5% trichloroacetic acid. Quantitative data showed that the prolactin secreting cells increase during pregnancy, lactation and estrone treatment. Estrone at low dose levels caused immense hyperplasia whereas at higher levels there was no corresponding increase in the percentage of type I cells. Ultrastructurally, prolactin secreting cells are characterised by the presence of stacked endoplasmic reticulum, oval or irregular secretory granules. The Golgi apparatus is seen rich in vacuolar system.     

Effect of salinity on stomatal number,size and opening in barley Genotypes

Salinity had a varying effect on stomatal frequency, size and pore in barley (Hordeum vulgare L.). This variation in stomatal frequency, size and pore under salinity offers a scope of selecting cultivars with lesser increase in stomatal number to avoid excessive loss of water due to transpiration without effecting photosynthetic efficiency.     

Effect of Nucleotides and Related Compounds on Glutamine Synthetase Activity in Chick Embryo Retina: A Biochemical and Immunohistochemical Study

Abstract: The effect of a number of nucleotides and related compounds on glutamine synthetase (GS) induction in retina from 12-day chick embryo was studied with both biochemical and immunohistochemical techniques. A number of these compounds gave rise to GS activity comparable to that induced by treatment with cortisol, which is known to give rise to precocious induction of the enzyme in this system. Of the cyclic nucleotides examined, cAMP (0.5-1.2 × 10^?3 M) gave essentially no increase in GS activity. In contrast, dibutyryl cAMP (0.8 × 10^?3 M) had a more significant effect on GS activity, as did 8-bromo-cAMP and cGMP at the same concentration. The activity elicited by these nucleotides was generally half that obtained by treatment with 2.8 × 10^?7 M-cortisol for the same length of time, 8-Bromo-cGMP (0.8 × 10^?3 M) had an effect comparable to the aforementioned concentration of cortisol. Since phosphodiesterase activity is minimal in the chick retina at 12 days of development, addition of isobutylmethylxanthine (1 × 10^?5 M) to this system had, as would be expected, little effect on GS activity. Of the noncyclic compounds, 8-bromoguanosine often gave rise to GS activity comparable to that obtained with cortisol. The other compounds (8-bromo-5′-GMP, guanosine, adenosine, and 5′-AMP) generally had less of an effect on GS. In general, the degree of staining in the immunohistochemical localization of GS corresponded well with the biochemical results and showed the enzyme to be present in regions consistent with the distribution of Muller cells and their processes. Thin-layer chromatography and radioimmunoassay of the nucleotides did not show any steroid impurity in any of the compounds used in the study, even when determinations were carried out at five times the concentration of nucleotide used in the experiments.