University of Wisconsin–Rock County

About: University of Wisconsin–Rock County is a based out in . It is known for research contribution in the topics: Discrete element method & Genus. The organization has 15 authors who have published 27 publications receiving 668 citations.

The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle

Abstract: Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host–microbe symbioses.

Two New Species of Paramoeba from Maine

Abstract: SYNOPSIS Four clonal strains of amoebae isolated from salt-water habitats of the Maine coast show the characteristic Nebenkorper or paranucleus of the genus Paramoeba Schaudinn, 1896, this being the first report of free-living members of that genus from North America. The isolates are identified as 2 species, P. pemaquidensis n. sp. and P. aestuarina n. sp. In form and mitotic pattern, these 2 species resemble members of the family Mayorellidae.

A Comparative Study of the Assimilation of the Chinese in New York City and Lima, Peru

Abstract: A comparative study of assimilation like the present one has shown that the structural or environmental factors in the larger society are principally responsible for the differential rates of assimilation. Historically, the United States has been racist in its treatment of nearly all immigrants. Eastern and Southern Europeans were judged inferior along ethnic/racist lines (Gordon 1964), let alone those with more pronounced physical characteristics such as blacks, Latins or Asians. The legal structure erected in the United States, which includes the historical anti-ethnic legisla- tion, discriminatory immigration policies and racist miscegenation laws, reflects the attitudes and perceptions of the host society. The long years of unfair policies and discriminatory practices implemented against the Chinese produced feelings of rejection among them. In Lima, by contrast, the Hispanic cultural tradition does not emphasize racial differences. Although therere is a subtle racism in Lima, there is no miscegenation law, and children born of marriages between Chinese and Peruvians become important factors in the assimilation of the Chinese.

Platyamoeba stenopodia n. g., n. sp., a freshwater amoeba.

Abstract: SYNOPSIS. Platyamoeba stenopodia n. g., n. sp., isolated from a lake in Alabama, is an amoeba with flattened form, usually more than 2.5 × as long as broad, the anterior half hyaline and the posterior half granular, with a single vesiculate nucleus at the posterior edge of the hyaline region. It forms a transitory floating stage with slender, hyaline pseudopods. Its cyst is spherical, uninucleate, with a smooth inner wall and a thinner, closely applied outer wall, which is often slightly wrinkled. Length of locomotive amoeba 15–36 μ diameter of cyst 7–11.5 μ Reproduction by binary fission with mesomitotic nuclear division, the nuclear membrane disappearing in prophase. The genus Platyamoeba is erected for amoebae including this organism; the type species is P. placida.