Amyloidosis development in LLC mice

Using electron microscopy and the protein A-gold labelling technique we studied amyloidosis in the LLC mice, an inbred strain developing amyloidosis spontaneously. We found that the reticular cells lining around the sinuses in the red pulp of the spleen were converted to amyloid. Evidence suggests that the amyloid originates in the cells themselves. The process of amyloid formation is discussed.     

The coastal salt marshes of California and Baja California

A comparative study of the North American salt marshes between Magdalena Plain (Baja California, 24° N)_and the north of San Francisco (California 38° N) is made in order to establish relationships between floristic and zonal gradients. The sigmatistic-phytosociological method along with Average Linkage Clustering are used to describe the zonation of these salt marshes and to define the optimum zone of several halophilous plants and communities.Abbreviations (As) Arthrocnemum subterminalis - (Ds) Distichlis spicata - (Fg) Frankenia salina - (Jc) Jaumea carnosa - (MI) Monanthochloe littoralis - (S1) Sarcocornia pacifica, prostrate biotype - (S2) Sarcocornia pacifica, erect biotype - (Sp) Spartina foliosa     

Mid-eocene climatic change,Southwestern California and Northwestern Baja California

A widespread paleosol of Paleocene and Early Eocene age occurs in southwestern California and northwestern Baja California. The dominant quartz-kaolinite mineralogy and cation-depleted chemistry of the buried soil indicate a humid, tropical paleoclimate similar to the modern equatorial belt. Although the Paleocene—Eocene paleomagnetic latitudes are similar to the modern latitudes (36–37°N to 32–33°N, respectively), rainfall was about 125–190 cm per year and average annual temperature was about 20–25°C in marked contrast to the present annual rainfall of 25 cm and average annual temperature of 16°C.A variety of indicators in the Late Eocene sedimentary succession suggests a change to a semi-arid paleoclimate. The nonmarine portions of the Late Eocene sedimentary record are dominated by a cobble conglomerate lithosome deposited in fluvial, alluvial fan and fan delta systems. Intertongued with the conglomerate is a sandstone lithosome deposited in flood-plain and nearshore marine environments. The conglomerate clasts were transported to the depositional site via a long-distance (200–300 km), moderate gradient, braided river system mostly by flash floods. Characteristic post-depositional, in situ fracturing of conglomerate clasts probably occurred due to salt crystallization.Within the flood plain sandstones, and to a lesser degree the conglomerates, are multiple well-developed caliche horizons of probable pedogenic origin. Clay minerals from the Late Eocene rocks are dominantly vermiculite and smectite with lesser chlorite and illite; this is in marked contrast to the kaolinite that comprises the underlying Early Paleogene lateritic paleosol.The character of the Late Eocene sedimentary succession indicates a semi-arid climate. Rainfall probably did not exceed 63 cm per year; it probably was seasonal and by occasional flash floods. This paleoclimate contrasts markedly with the earlier humid tropical paleoclimate and must indicate a widespread climatic change in late Middle Eocene time.