An increase in intracellular Ca2+ concentration ([Ca2+]) and morphological were simultaneously observed by epifluorescence and differential interference contrast (DIC) microscopy during fertilization of the sand dollar, Clypeaster japonicus. [Ca2+], which was detected by a Ca2+ indicator, Fluo-3, initially increased just beneath the sperm-attached site on the egg surface 8.6 sec after attachmen...

We summarize information concerning Recent and Pleistocene-Holocene Uruguayan sand dollars (Mellitidae), as well as Miocene taxa (Monophorasteridae). Recent and Pleistocene-Holocene species (Encope emarginata, Mellita quinquiesperforata, and Leodia sexisperforata) are at their southernmost limits of distribution, with only E. emarginata recorded further south than Uruguay. Lower temperatures to...

Many larvae and other plankton have complex and variable morphologies of unknown functional significance. We experimentally and theoretically investigated the functional consequences of the complex morphologies of larval sand dollars, Dendraster excentricus (Eschscholtz), for hydrodynamic interactions between swimming and turbulent water motion. Vertical shearing flows (horizontal gradients of ...

Different types of soil respond variably to biochar amendment. Soil structure and fertility are properties which strongly affect the impacts on microbial activity. A pot experiment with lettuce was conducted verify whether amendment is more beneficial in sandy than clay soil. The nutrient content (carbon nitrogen), biomass carbon, respiration, metabolic quotient, plant yield were determined. tr...

Abstract. Over the last 30 years, in situ cosmogenic nuclides (CNs) have revolutionized surficial processes and Quaternary geologic studies. Commonly measured CNs extracted from common mineral quartz long half-lives (e.g., 10Be, 26Al) been applied over timescales a few hundred years to millions of years. However, their also render them largely insensitive complex histories burial exposure less ...

SUMMARY A method for cytochemical fractionation of the Lettré-Ehrlich ascites tumor has been presented. The cells were exposed to dilute Ringer solution which increased the cell size and rigidity and allowed them to be homogenized in 0.44 M sucrose with the use of the Dounce all-glass "ball and cylinder" homogenizer. Nuclear, mitochondrial, and microsome + "soluble" fractions were obtained and...