Responses of the Oat Coleorhiza to Various Treatments in Culture

Author Institution: Biology Department, Wittenberg College, Springfield, Ohi

Polyembryony in Hierochloe Odorata (L.) Beauv.

Author Institution: Biology Department, Wittenberg College, Springfield, Ohi

A quantitative comparison of dispersed spore/pollen and plant megafossil assemblages from a Middle Jurassic plant bed from Yorkshire, UK

Detailed quantitative data has previously been collected from plant megafossil assemblages from a Middle Jurassic (Aalenian) plant bed from Hasty Bank, North Yorkshire, UK. We conducted a similar analysis of palynological dispersed sporomorph (spore and pollen) assemblages collected from the same section using the same sampling regime: 67 sporomorph taxa were recorded from 50 samples taken at 10 cm intervals through the plant bed. Basic palynofacies analysis was also undertaken on each sample. Both dispersed sporomorph and plant megafossil assemblages display consistent changes in composition, diversity (richness), and abundance through time. However, the dispersed sporomorph and plant megafossil records provide conflicting evidence for the nature of parent vegetation. Specifically, conifers and ferns are underrepresented in plant megafossil assemblages, bryophytes and lycopsids are represented only in sporomorph assemblages, and sphenophytes, pteridosperms, Caytoniales, Cycadales, Ginkgoales and Bennettitales are comparatively underrepresented in sporomorph assemblages. Combined multivariate analysis (correspondence analysis and nonmetric multidimensional scaling) of sporomorph occurrence/abundance data demonstrates that temporal variation in sporomorph assemblages is the result of depositional change through the plant bed. The reproductive strategies of parent plants are considered to be a principal factor in shaping many of the major abundance and diversity irregularities between dispersed sporomorph and plant megafossil data sets that seemingly reflects different parent vegetation. Preferential occurrence/preservation of sporomorphs and equivalent parent plants is a consequence of a complex array of biological, ecological, geographical, taphonomic, and depositional factors that act inconsistently between and within fossil assemblages, which results in notable discrepancies between data sets

Antimicrobial and antimutagenic activity of probiotics

Pojavom, antibiotik-rezistentnih bakterija, koncept probiotika kao prirodnog načina sprječavanja rasta patogenih bakterija postaje vrlo zanimljiv. Probiotici su definirani kao živi mikrobni dodatak hrani koji osigurava povoljan učinak na domaćina, te poboljšava ravnotežu mikroflore njegovog probavnog sustava. U humanoj prehrani najčešće se kao probiotici koriste bakterije Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum. Bifidobacterium longum i kvasac Saccharomyces boulardii. Probiotici proizvode organske kiseline od kojih su octena, mliječna i pirogrožđana u najvećoj količini. Neki istraživači vjeruju da je mliječna kiselina jedina značajna antimikrobna tvar. Prikazana je antimutagena aktivnost octene, maslačne, mliječne i pirogrožđane kiseline koje proizvode probiotici, prema 8 mutagenih ili promutagenih tvari.With the emergence of antibiotic-resistant bacteria, the concept of probiotics as a natural way of suppressing pathogens has attracted much attention. Probiotics are defined as a "live microbial good supplement, which provide beneficial effects on the host by improving its intestinal microbial balance." Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum, Bifidobacterium longum and the yeast Saccharomyces boulardii are the most commonly organisms used as probiotics in human diet. Probiotic bacteria produce several organic acids with acetic, lactic and pyruvic acid being the major ones. Several researches belive that lactic acid is the only antimicrobial agent of importance. The antimutagenic activity of acetic, butyric, lactic and pyruvic acids, produced by probiotics, versus 8 mutagens or promutagens is reported

Osmoregulation and appetite regulation in a basal vertebrate, the sea lamprey (Petromyzon marinus)

Lamprey (Petromyontiformes) are the oldest extant family in the vertebrate lineage, providing a unique phylogenetic position for studies on vertebrate evolution. As a basal vertebrate, sea lamprey (Petromyzon marinus) is an important species to understand evolution and comparative physiological mechanisms, including osmoregulation and appetite regulation. Sea lamprey has anadromous (native to the Atlantic Ocean) and landlocked (invasive in the Laurentian Great Lakes in North America) populations. In both populations of sea lamprey, the blind filter-feeding freshwater (FW) larvae burrow in stream sediments for until undergoing a hormonal-driven metamorphosis. During this phase, sea lamprey do not feed as major morphological and physiological changes occur, including the development of salinity tolerance and parasitic anatomy. After metamorphosis, sea lamprey migrate to the ocean (anadromous), or FW lakes (landlocked) where they attach to a host and feed parasitically. After a rapid growth phase, adults return to FW streams to spawn and die. In this thesis, I examine the osmoregulation and appetite regulation of sea lamprey. In Chapter 2, I describe the osmoregulatory and ionoregulatory capacities of one anadromous (Connecticut River) and three landlocked (Lake Champlain, Hammond Bay, and Thunder Bay) populations exposed to FW or seawater (SW) over two weeks (Chapter 2). In Chapter 3, I functionally characterize a FW ion uptake transporter, the Na+:Cl- cotransporter (NCC) in the gill of sea lamprey across life stages and salinity environments. In Chapter 4, I compare physiological and hormonal differences between feeding and non-feeding parasitic juvenile sea lamprey, using specific growth rate and plasma triglycerides as confirmation for feeding behavior., I describe differences in appetite- and feeding- regulating hormones in the first feeding following metamorphosis. Collectively, this dissertation contributes to conservation and management practices for native and invasive sea lamprey, and it contributes to the knowledge of osmoregulation and appetite regulation in the context of vertebrate evolution

The Culture Of Excised Ovules, Endosperm And Embryos Of Certain Grasses.

PhDBotanyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/181566/2/0012630.pd

A study of muskrat productivity on a buttonbush swamp

Master of ScienceForestry and ConservationUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/113939/1/39015003269043.pd

Biology

xiv,126 hal,;ill,;31c