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.     

Demonstration and ontogenesis in the rat of a serum protein analogous to human thyroxine binding globulin

It has been reported evidence based on equilibrium binding, electrophoretic, immunoelectrophoretic studies, that the rat possesses a major high affinity thyroid hormone binding protein, with an electrophoretic mobility and binding properties similar to those of the human thyroxine binding globulin (TBG). It is shown that in the sera of postnatal developing animals, between 3 and 21 days, the thyroxine (T4) and the triiodothyronine (T3) binding activities increase up to 10 times over adult or foetal levels, due to a high transient post-natal surge of the rat TBG. In the adult serum, the TBG persists in decreased amounts: it then yields the predominant role as T4 carrier to the thyroid binding prealbumin (TBPA), but retains the major role as binder of T3, i.e. of the biologically active thyroid hormone.     

The isolation,characterization and application in the Triticeae of a set of wheat RFLP probes identifying each homoeologous chromosome arm

Summary To investigate the use of RFLP analysis in the Triticeae, a set of low copy number probes has been isolated from a wheat cDNA library. The probes identify each of the 14 homoeologous chromosome arms of wheat as determined by analysis of DNA fragments hybridizing to the probes in aneuploid lines of Chinese Spring. These probes can be used in RFLP analyses both for the assignment of homoeology of alien chromosomes or arms added to wheat, and for the determination of chromosome dosage in wheat aneuploids. Different chromosomes from various Triticeae species can therefore be followed in a wheat genetic background using a single technique. The potential uses of the set in facilitating the transfer of alien segments into wheat are outlined.     

Binding activities of thyroxine binding globulin versus thyroxine binding prealbumin in rat sera: differential modulation by thyroid hormone ligands, oleic acid and pharmacological drugs

We use gel equilibration and electrophoretic techniques to compare the binding properties of thyroxine binding globulin and thyroxine binding prealbumin in rat sera. The evidence indicates that TBG bears the serum lowest capacity highest affinity sites for thyroxine (T4) and triiodothyronine (T3) (Ka1 greater than or equal to 10(9) M-1) as well as weaker saturable T3 sites (Ka2 approximately 10(8) M-1). TBPA bears for T4 only Ka2 approximately 10(8) M-1 sites and for T3 only Ka approximately 10(6) M-1 sites. Consistent with these parameters are the specific responses of TBG and TBPA binding activities to varying serum concentrations of T4, T3, oleic acid, the drugs diphenylhydantoin or salicylate. The primary attack of these compounds is aimed at TBG. Small T4, oleate or DPH doses chase the TBG-bound T4 to TBPA, high doses of T4 or oleate but not of DPH inhibiting the T4 binding to both proteins. In the T3-serum interactions, all tested compounds displace the TBG-bound hormone without chasing it to TBPA. The high reactivity of TBG sites designates the protein as crucially involved in modulating the free vs bound serum levels of T4 and T3 against physiological or pathological variations of binding competitors.     

PACAP, a VIP-like peptide, in neurons of the esophagus.

The lower esophagus of guinea-pig, cat, sheep and man was analyzed for pituitary adenylate cyclase activating peptide (PACAP), a novel vasoactive intestinal peptide (VIP)-like peptide, using immunocytochemistry and radioimmunoassay. PACAP-immunoreactive nerve fibers were numerous in the longitudinal and circular muscle layers of sheep and man, moderate in numbers in cat, while being few in the esophagus of guinea-pig. A few PACAP-immunoreactive nerve cell bodies and numerous nerve fibers were seen in the myenteric ganglia of the esophagus of cat, sheep and man. In the lower esophagus of cat, sheep and man all PACAP-containing nerve cell bodies and nerve fibers stored VIP. The results of radioimmunoassay of PACAP in extracts of specimens from man were in good agreement with the immunocytochemical findings. High performance liquid chromatography revealed one major peak of PACAP-like immunoreactivity in extracts of human esophagus. We suggest that neuronal PACAP may serve to modulate motor activity and secretion in the lower esophageal sphincter region.     

Characteristics of the relative maximum in the decay of delayed light emission from Pothos leaf following far-red excitation

Following illumination with wavelengths longer than 700 nm, the intensity of light emission from Pothos aurea leaf falls for 1 min and then increases to a maximum after 2 min in the dark. The spectrum of this minute-range liminescence matches that of prompt fluorescence excited at the same wavelength, but differs from that of prompt or minute-range delayed emission excited by wavelengths shorter than 700 nm. This emission is less sensitive to heat damage than millisecond delayed emission, and may originate from photosystem I.