Bats of the White and Inyo Mountains of California-nevada

We surveyed bats throughout the White and Inyo Mountains of California and Nevada. From December 1990 to November 1996, we surveyed hibernating bats, and foraging bats from June 1992 to September 1996. The White-Inyo Range rests in a unique biogeographical junction between the Sierra Nevada, Mojave Desert, and Great Basin Regions. Elevational gradients of 305-4340 m, combined with limited human development, further enhance the interest of natural history and faunal distributions in this range. We found 13 bat species in the course of 2668 observations. Three of these species, the spotted bat ( Euderma maculatum ), silver-haired bat ( Lasionycteris noctivagans ), and hoary bat ( Lasturus cinereus ), have no previous records from the White-Inyo Range. We found bats in all vegetation zones except alpine, 3500-4342 m. Despite an abundance of mines in this range, only Townsend's big-eared bat ( Corynorhinus townsendii ) and western small-footed myotis ( Myotis ciliolabrum ) used them routinely. Our data also indicated the importance of surface water to bat populations in arid regions.     

Action and interactions at microtubule ends

Microtubule dynamic instability is fundamentally important to the way cells respond to their environment and segregate their genetic material. A disparate class of proteins defined by their localisation to growing microtubule plus ends ('+TIPS') play a key role in controlling microtubule dynamics and organisation. They directly impact upon the behaviour of the microtubule tip and link this structure to interfaces that include kinetochores and the cortex of the cell. Surprisingly, some +TIPs also have important functions at the microtubule minus end. These properties contribute to the important roles played by +TIPs in processes such as mitosis and cell migration. This review examines how recent advances have impacted our understanding of +TIP function in mammalian cells, with emphasis on the emergence of the EB1 family as a core component of +TIP activities. An overview of the use of +TIP imaging as a tool for the cell biologist is also presented.     

Late Pleistocene mollusks from the southern Black Hills, South Dakota

Pleistocene-age mollusks recovered from the Nelson-Wittenberg Site and Mammoth Site provide information on paleoenvironments of the southern Black Hills, South Dakota. New mollusk records for the Mammoth Site include Vertigo modesta, Catinella sp., and Gyraulus parvus . The presence of V. modesta, Columella columella alticola , and Pupilla muscorum at the Nelson-Wittenberg Site suggests cooler than modern conditions in the Black Hills during the Pleistocene. Although the majority of identified taxa are consistent with previous interpretations of an arid, shrubsteppe environment for the Black Hills during the Wisconsin Glaciation, V. modesta and C. c. alticola suggest the presence of at least some isolated, local mesic areas.     

Influence of yellow starthistle ( Centaurea solstitialis ) on small mammals in central California

Yellow starthistle ( Centaurea solstitialis ) is native to Europe and Asia and has quickly invaded disturbed grasslands and rangelands in the western United States. The purpose of our study was to determine the effects of starthistle on rodents at Beale Air Force Base, Yuba County, California, by examining rodent species diversity, species abundance, age structure, and reproductive condition among locations with low, medium, and high percent cover and height of starthistle. Listed in decreasing order of abundance, the rodents were house mouse ( Mus musculus ), California vole ( Microtus californicus ), deer mouse ( Peromyscus maniculatus ), western harvest mouse ( Reithrodontomys megalotis ), and roof rat ( Rattus rattus ). Indices of diversity did not differ among starthistle cover categories. Regression analyses showed that Reithrodontomys megalotis was more abundant in high-cover starthistle plots, with 90.5% of captures occurring in at least 40% starthistle cover. Significant differences were found in capture rates, reproduction, and age between season only. To manage for all rodent species, an area with medium percent cover and height of starthistle will likely provide adequate protective cover.     

Den and relocation site characteristics and home ranges of Peromyscus truei in the White Mountains of California

We used ratio telemetry to describe nighttime movements and daytime den sites of pinyon mice ( Peromyscus truei ) in the White Mountains of California, 1991-1993. Characteristics of nighttime relocations and den sites for mice concurred with previously reported habitat-use information for the species and supported the claim that pinyon mice use multiple daytime sites. However, males and females were associated with different habitat characteristics at den sites, indicating differential microhabitat selection by the sexes, perhaps related to reproductive constraints on females. Pinyon mice also exhibited high variability in den site habitat use in the summer, but low variability in the fall and winter. The dens of male mice were farther apart than those of females, and home range areas averaged 2.9 ha ( s = 4.27 ha) for 8 males , and 0.8 ha ( s = 0.76 ha) for 7 females (overall ￣ x = 1.7 + 2.97 ha). These areas were larger than those reported for other species of Peromyscus . The combined effects of drought and reduced food availability may have contributed to the larger areas used.     

Tumorigenic transformation by CPI-17 through inhibition of a merlin phosphatase

The tumour suppressor protein merlin (encoded by the neurofibromatosis type 2 gene NF2) is an important regulator of proliferation in many cell and tissue types. Merlin is activated by dephosphorylation at serine 518 (S518), which occurs on serum withdrawal or on cell-cell or cell-matrix contact. However, the relevant phosphatase that activates merlin's tumour suppressor function is unknown. Here we identify this enzyme as the myosin phosphatase (MYPT-1-PP1delta). The cellular MYPT-1-PP1delta-specific inhibitor CPI-17 causes a loss of merlin function characterized by merlin phosphorylation, Ras activation and transformation. Constitutively active merlin (S518A) reverses CPI-17-induced transformation, showing that merlin is the decisive substrate of MYPT-1-PP1delta in tumour suppression. In addition we show that CPI-17 levels are raised in several human tumour cell lines and that the downregulation of CPI-17 induces merlin dephosphorylation, inhibits Ras activation and abolishes the transformed phenotype. MYPT-1-PP1delta and its substrate merlin are part of a previously undescribed tumour suppressor cascade that can be hindered in two ways, by mutation of the NF2 gene and by upregulation of the oncoprotein CPI-17.