Radioimmunoassay of progesterone in uterine flushings of buffalo (Bubalus bubalis)

Summary The concentration of progesterone as determined by radioimmunoassay varied in accordance with the phase of ovarian activity.The authers are indebted to Dr. D. Sundaresan, for the encouragement during the course of study. Progesterone antiserum from Dr. B.J.A. Furr is gratefully acknowledged.     

Flares from a candidate Galactic magnetar suggest a missing link to dim isolated neutron stars

Magnetars are young neutron stars with very strong magnetic fields of the order of 10(14)-10(15) G. They are detected in our Galaxy either as soft gamma-ray repeaters or anomalous X-ray pulsars. Soft gamma-ray repeaters are a rare type of gamma-ray transient sources that are occasionally detected as bursters in the high-energy sky. No optical counterpart to the gamma-ray flares or the quiescent source has yet been identified. Here we report multi-wavelength observations of a puzzling source, SWIFT J195509+261406. We detected more than 40 flaring episodes in the optical band over a time span of three days, and a faint infrared flare 11 days later, after which the source returned to quiescence. Our radio observations confirm a Galactic nature and establish a lower distance limit of approximately 3.7 kpc. We suggest that SWIFT J195509+261406 could be an isolated magnetar whose bursting activity has been detected at optical wavelengths, and for which the long-term X-ray emission is short-lived. In this case, a new manifestation of magnetar activity has been recorded and we can consider SWIFT J195509+261406 to be a link between the 'persistent' soft gamma-ray repeaters/anomalous X-ray pulsars and dim isolated neutron stars.     

Bidirectional motility of kinesin-5 motor proteins: structural determinants,cumulative functions and physiological roles

Mitotic kinesin-5 bipolar motor proteins perform essential functions in mitotic spindle dynamics by crosslinking and sliding antiparallel microtubules (MTs) apart within the mitotic spindle. Two recent studies have indicated that single molecules of Cin8, the Saccharomyces cerevisiae kinesin-5 homolog, are minus end-directed when moving on single MTs, yet switch directionality under certain experimental conditions (Gerson-Gurwitz et al., EMBO J 30:4942–4954, 2011; Roostalu et al., Science 332:94–99, 2011). This finding was unexpected since the Cin8 catalytic motor domain is located at the N-terminus of the protein, and such kinesins have been previously thought to be exclusively plus end-directed. In addition, the essential intracellular functions of kinesin-5 motors in separating spindle poles during mitosis can only be accomplished by plus end-directed motility during antiparallel sliding of the spindle MTs. Thus, the mechanism and possible physiological role of the minus end-directed motility of kinesin-5 motors remain unclear. Experimental and theoretical studies from several laboratories in recent years have identified additional kinesin-5 motors that are bidirectional, revealed structural determinants that regulate directionality, examined the possible mechanisms involved and have proposed physiological roles for the minus end-directed motility of kinesin-5 motors. Here, we summarize our current understanding of the remarkable ability of certain kinesin-5 motors to switch directionality when moving along MTs.     

Radioimmunoassay of cortisol in blood of buffaloes (Bubalus bubalis) during the oestrous cycle

Summary Changes in the concentration of cortisol were measured by radioimmunoassay in the blood plasma of buffaloes (Bubalus bubalis). There were minor fluctuations in the level during the oestrous cycle, but the differences between the days were not significant. The study revealed that cortisol under normal conditions does not appear to be involved in the regulation of the cycle.The authors are indebted to Dr D. Sundaresan for his keen interest in the study and to Dr A.E. Leek, Technia Diagnostics, for providing cortisol antiserum.     

A new indian source of diosgenin (Costus speciosus)

Zusammenfassung Eine neue, ergiebige Quelle zur Gewinnung von Diosgenin ausCostus speciosus wird beschrieben.     

Response of serum calcium to administration of an extract from Stannius corpuscles in the anurans

Summary The effect of i.p. injection of an aqueous extract of Stannius corpuscles (10 mg/ml/100 g b.wt) on serum calcium levels was investigated inRana cyanophlyctis andBufo andersonii. This treatment evokes in both species hypocalcemia over a period of 1–4 h, followed by hypercalcemia at 6 h, with a return to control at 8 h.