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Articles 901 - 930 of 932

Full-Text Articles in Biology

Inflorescence Architecture And Evolution In The Fagaceae, Robert B. Kaul, Ernst C. Abbe Jan 1984

Inflorescence Architecture And Evolution In The Fagaceae, Robert B. Kaul, Ernst C. Abbe

School of Biological Sciences: Faculty Publications

First paragraph:

Inflorescence architecture is receiving increasing attention with respect to its role in the life of plants, but much remains to be learned of its effects on pollination and dispersal biology (see Wyatt, 1982). Little is known of the biology of fagaceous inflorescences or of their relationships with the growth or the reproductive patterns of the trees. Most studies (Abbe, 1974; Macdonald, 1979; Fey & Endress, 1983) have concentrated on the nature of the flower clusters (often called dichasia or partial inflorescences) and cupules. Hjelmqvist (1948) and Soepadmo (1972) briefly reviewed the variety of inflorescences in the Fagaceae. Čelakovský …


An Rna Virus In Autographa Californica Nuclear Polyhedrosis Virus Preparations: Gross Pathology And Infectivity, P. V. Vail, Thomas Jack Morris, S. S. Collier Jan 1983

An Rna Virus In Autographa Californica Nuclear Polyhedrosis Virus Preparations: Gross Pathology And Infectivity, P. V. Vail, Thomas Jack Morris, S. S. Collier

School of Biological Sciences: Faculty Publications

The pathology and infectivity of an RNA virus infectious to Trichoplusia ni larvae was investigated. The enzyme-linked immunosorbent assay (ELISA) and weight depression were used as criteria for virus concentration in larval homogenates and live larvae, respectively. Infected larvae were severely stunted, weighing as little as 13 times less than uninfected individuals of the same age , yet appeared normal morphologically. The virus was found to cause only slight mortality at high concentrations. Infected larvae displayed the pathological stunting response down to a dose of 0.1 ng of virus. Larvae infected with doses 100 times lower did not show the …


Heligmosomoides Thomomyos Sp. N. (Nematoda: Heligmosomidae) From Pocket Gophers, Thomomys Spp. (Rodentia: Geomyidae), In Oregon And California, Scott L. Gardner, Douglas Jasmer Jan 1983

Heligmosomoides Thomomyos Sp. N. (Nematoda: Heligmosomidae) From Pocket Gophers, Thomomys Spp. (Rodentia: Geomyidae), In Oregon And California, Scott L. Gardner, Douglas Jasmer

Scott L. Gardner Publications

The nematode Heligmosomoides thomomyos sp. n. is described from the small intestine of Thomomys bulbivorus and T. bottae. This is the first report of Heligmosomoides from rodents of the family Geomyidae.

Nematodes of the genus Heligmosomoides Hall, 1916 occur most commonly in arvicolid rodents. Of the 26 known species of the genus, 11 have been recorded from Nearctic rodents (Rausch and Rausch, 1973). In North America, Heligmosomoides spp. have been recorded not only from voles, but also from cricetids and murids. Heligmosomoides spp. characteristically inhabit the small intestine or cecum of their host, where they usually are found …


The Ecology Of Mutualism, Douglas H. Boucher, Sam James, Kathleen H. Keeler Jan 1982

The Ecology Of Mutualism, Douglas H. Boucher, Sam James, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Elementary ecology texts tell us that organisms interact in three fundamen­ tal ways, generally given the names competition, predation, and mutualism. The third member has gotten short shrift (264), and even its name is not generally agreed on. Terms that may be considered synonyms, in whole or part, are symbiosis, commensalism, cooperation, protocooperation, mutual aid, facilitation, reciprocal altruism, and entraide. We use the term mutual­ism, defined as "an interaction between species that is beneficial to both," since it has both historical priority (311) and general currency. Symbiosis is "the living together of two organisms in close association," and …


Analysis Of A Controlling-Element Mutation At The Adh Locus Of Maize, John Osterman, Drew Schwartz Jan 1981

Analysis Of A Controlling-Element Mutation At The Adh Locus Of Maize, John Osterman, Drew Schwartz

School of Biological Sciences: Faculty Publications

A Ds-suppressed Adh mutant was isolated by the allyl alcohol pollen selection

technique. The mutant produces a reduced level of an altered thermolabile

enzyme suggesting that the Ds element is inserted in the Adh structural gene.

The mutant protein is enzymatically active and does not differ detectably in

size from the progenitor protein. A number of possible explanations for the data

are presented.


Inflorescence Architecture And Flower Sex Ratios In Sagittaria Brevirostra (Alismataceae), Robert B. Kaul Oct 1979

Inflorescence Architecture And Flower Sex Ratios In Sagittaria Brevirostra (Alismataceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

Two populations of Sagittaria brevirostra from the same lake were sampled 10 years apart and yielded similar data on inflorescence structure and on numbers and ratios of male and female flowers. Larger inflorescences have relatively more male than female flowers than do smaller inflorescences. Pollination success is unrelated to inflorescence size or sex ratio within an inflorescence.


Agar Plate Culture Of Selected Trypanosomatidae, Amy Doran Keppel Aug 1979

Agar Plate Culture Of Selected Trypanosomatidae, Amy Doran Keppel

School of Biological Sciences: Dissertations, Theses, and Student Research

Summary

The study of trypanosomatid biology would benefit greatly from the acquisition of a tool for culturing such as those used in microbiology. Agar plate culture has been described several times, but until the present its potential for use in this area has been underestimated. The previous work has demonstrated that this culture method may be used to culture a wide variety of species, that these species give rise to identifiable colony phenotypes, and that these are stable regardless of the life cycle stage used to initiate the culture. It was also shown that colonies could be initiated from the …


Anatomical Observations On Floating Leaves, Robert B. Kaul Jan 1976

Anatomical Observations On Floating Leaves, Robert B. Kaul

School of Biological Sciences: Faculty Publications

An examination of 24 genera of aquatic plants having floating leaves and leaf-like thalli has been made. Functional stomata occur on the adaxial sides of floating leaves of angiosperms and some ferns, and in some floating leaves there are stomata on the abaxial surface as well. Most floating leaves have prominently chambered mesophyll, and in some instances the chambers are locally enlarged and form buoys.


A Pollen Selection System For Alcohol-Dehydrogenase-Negative Mutants In Plants, Drew Schwartz, John Osterman Jan 1976

A Pollen Selection System For Alcohol-Dehydrogenase-Negative Mutants In Plants, Drew Schwartz, John Osterman

School of Biological Sciences: Faculty Publications

Exposure of freshly shed maize pollen to allyl alcohol vapors allows selective fertilization by mutant alcohol-dehydrogenase-negative grains. Wild-type pollen grains are killed by the enzymatic conversion of allyl alcohol to the highly toxic acrylaldehyde.


Biological Diffusion Processes, Allen R. Killpatrick, Norman J. Chonacky Jan 1975

Biological Diffusion Processes, Allen R. Killpatrick, Norman J. Chonacky

Physical Science Modules for Bioscience Students

What happens in the lung is that air meets blood. Figure 1 shows the lung's architecture. Focus your attention upon the smallest scale structures which are the termini of the air passages. These are the alveolar air sacs or, simply, alveoli. The inhalation/exhalation actions of the lung, alternately, flood these alveoli with atmospheric air and expel its oxygen-poor/carbon dioxide-rich replacement. Figure (2a) depicts, in a somewhat simplified manner, these alveoli with their appended venous blood suppliers, the pulmonary arteries. Figure {2b} shows the structure of the blood distribution system over a small, typical portion of the alveolar surface in much …


Review Of Die Infloreszenzen: Typologie Und Stellung Im Aufbau Des Vegetationskorpers. Zweiter Band. 1 Teil, By Wilhelm Troll. Gustav Fischer, Jena, 1969, Robert B. Kaul Jun 1970

Review Of Die Infloreszenzen: Typologie Und Stellung Im Aufbau Des Vegetationskorpers. Zweiter Band. 1 Teil, By Wilhelm Troll. Gustav Fischer, Jena, 1969, Robert B. Kaul

School of Biological Sciences: Faculty Publications

Review of Die Infloreszenzen: Typologie und Stellung im Aufbau des Vegetationskorpers. Zweiter Band. 1 Teil, by Wilhelm Troll. Gustav Fischer, Jena, 1969.


Morphology And Development Of The Flowers Of Boottia Cordata, Ottelia Alismoides, And Their Synthetic Hybrid (Hydrocharitaceae), Robert B. Kaul Sep 1969

Morphology And Development Of The Flowers Of Boottia Cordata, Ottelia Alismoides, And Their Synthetic Hybrid (Hydrocharitaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The inferior ovary of Boottia cordata, Ottelia alismoides, and their hybrid is appendicular in nature, the carpels are congenitally only slightly connate, and they are unsealed. All floral organs except the sepals originate from common primordia in the female and bisexual flowers. A flat residual floral apex is present. There is a vestigial superior ovary of three ontogeneticallv fused carpels in the male flower of Boottia cordata. The hybrid is intermediate in many characteristics and has partially fertile stamens and staminodia. The sequence of development in all flowers is acropetal. These plants appear to be related to …


Floral Morphology And Phylogeny In The Hydrocharitaceae, Robert B. Kaul Mar 1968

Floral Morphology And Phylogeny In The Hydrocharitaceae, Robert B. Kaul

School of Biological Sciences: Faculty Publications

The vascular anatomy of 13 of the 15 genera of the Hydrocharitaceae has been studied, and certain aspects of floral morphology are considered. The flowers of the family show a broad range of specialized structures combined with primitive characteristics. The origin of paired and single stamens is interpreted as probable modifications of fascicled stamens. Extreme reduction in the androecium is shown for several genera. Tendencies toward reduction and fusion within the gynoecium are pronounced. Most genera are at least slightly syncarpous, but a few are apocarpous. The inferior ovary is appendicular in nature, with some genera exhibiting more complete fusion …


Floral Development And Vasculature In Hydrocleis Nymphoides (Butomaceae), Robert B. Kaul Feb 1968

Floral Development And Vasculature In Hydrocleis Nymphoides (Butomaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The flower of Hydrocleis nymphoides consists of three sepals which arise in spiral succession, three simultaneously arising petals, numerous stamens and staminodia which arise in centrifugal order, and six carpels. A residual apex remains at maturity. The first-formed members of the androecium are stamens and the later-formed members are staminodia which develop below the stamens and which become outwardly displaced during expansion of the receptacle. The androecium is supplied by branching vascular trunk bundles. The carpels are completely open but the ventral margins are slightly conduplicately appressed basally. A single dorsal bundle provides the stigmatic area with vascular tissue, and …


Development And Vasculature Of The Flowers Of Lophotocarpus Calycinus And Sagittaria Latifolia (Alismaceae), Robert B. Kaul Aug 1967

Development And Vasculature Of The Flowers Of Lophotocarpus Calycinus And Sagittaria Latifolia (Alismaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The development of the bisexual flower of Lophotocarpus calycinus and of the unisexual flowers of Sagittaria latifolia has been observed. In all cases floral organs arise in acropetal succession. In L. calycinus, after initiation of the perianth, the first whorl of stamens to form consists of six stamens and is ordinarily followed by two alternating whorls of six stamens each. The very numerous carpels are initiated spirally. In the male flower of S. latifolia the androecium develops in spiral order. A few rudimentary carpels appear near the floral apex after initiation of the stamens. There are no staminodia. The female …


Phospholipids Of Thiobacillus Thiooxidans, J. M. Shively, A. A. Benson Jan 1967

Phospholipids Of Thiobacillus Thiooxidans, J. M. Shively, A. A. Benson

School of Biological Sciences: Faculty Publications

Cells and spent growth media from sulfur- and thiosulfate-grown cultures of Thiobacillus thiooxidans were analyzed. The phosphatides were examined by thinlayer chromatography, and the products of their hydrolysis by hydrochloric acid and methanolic potassium hydroxide were separated by paper chromatography. The phospholipids in both cells and spent growth media were identified as phosphatidyl ethanolamine, phosphatidyl N-monomethylethanolamine, phosphatidyl glycerol, and diphosphatidyl glycerol. These comprised about 97% of the total lipid phosphorus. Lyso-phosphatidyl-N-monomethylethanolamine and lysophosphatidylglycerol accounted for the remaining 3%. The percentage of the total lipid phosphorus accounted for by each phospholipid depended on the age of the culture.


Ontogeny And Anatomy Of The Flower Of Limnocharis Flava (Butomaceae), Robert B. Kaul Jan 1967

Ontogeny And Anatomy Of The Flower Of Limnocharis Flava (Butomaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The flowers of Limnocharis flava (L.) Buch. are borne in an indeterminate umbel and each consists of three sepals, three yellow petals, and about 18 carpels surrounded by numerous stamens and staminodia. The androecium is centrifugally developed, and the last-formed members are staminodial; it is supplied by branching vascular systems. Carpels arise almost simultaneously, and a prominent residual floral apex remains. The carpels are partially conduplicately closed and are also primitive in possessing laminar placentation and in lacking differentiation of a style. The gynoecium is essentially apocarpous, but there are slight fusions of adjacent carpels near their ventral margins where …


Utilization Of Peptones And Peptone Fractions By Bacteria, Margaret E. Mcmaster Jul 1941

Utilization Of Peptones And Peptone Fractions By Bacteria, Margaret E. Mcmaster

Open Access Master's Theses (through 2010)

An attempt was made to determine the minimum concentration of the different peptones which are necessary to support the growth of a group of aerobic microorganisms. The medium for this experiment was semi-solid glucose peptone agar, with the peptone being varied in amount and kind.

  1. The growth supporting properties of the peptones under investigation varied a great deal.
  2. The minimum concentration of peptone necessary for the growth of Shigella dysenteriae, Proteus vulgaris, Streptococcus lactis, and Salmonella pullorum was determined.
  3. Peptones appear to contain a substance which is toxic to Salmonella pullorum or else they lack a growth …


Anatomy And Histology Of The Digestive Tract Of A Deep-Sea Fish Coelorhynchus Carminatus, Elly M. Jacobsen Jan 1939

Anatomy And Histology Of The Digestive Tract Of A Deep-Sea Fish Coelorhynchus Carminatus, Elly M. Jacobsen

University Studies (University of Nebraska) (1888–1984)

This paper deals with the anatomy and histology of the digestive tube of one of the grenadiers or rat-tails, Coelorhynchus carminatus (Goode), as classified by Jordan & Evermann (1896).1 Many studies on the structure of the digestive tracts of fishes have been made in the past, and pioneer work in the teleost group was done by Valatour in 1861, Pillet in 1894 on the Pleuronectidae, and Gulland in 1898 on the salmon. More recent studies have been made by Greene (1912) on the king salmon, Blake 2 (1930) on the sea bass, and Rogick (1931) on the minnow.

The species …


Some Monogenetic Trematodes From The Galapagos Islands And The Neighboring Pacific, Frank Grose Meserve Aug 1935

Some Monogenetic Trematodes From The Galapagos Islands And The Neighboring Pacific, Frank Grose Meserve

School of Biological Sciences: Dissertations, Theses, and Student Research

Introduction

Trematodes are parasitic, unsegmented, flattened (rarely cylindrical) worms. They have ventral, anterior, posterior or median attachment organs. The sense organs are poorly developed. The mouth is terminal or ventral and subterminal. The intestine is usually forked with or without lateral branches. The animals, with few exceptions, are hermaphroditic. The ovary is usually single. They have one, two, or more testes. The development is direct with only one host in the ectoparasitic Monogenea and indirect in the Digenea which have two or more hosts. The digenetic trematodes usually parasitize vertebrates which serve as their primary hosts and invertebrates (Mollusca) which …


Further Studies In The Ecotone Between Prairie And Woodland, R. J. Pool, J. E. Weaver, F. C. Jean Jan 1918

Further Studies In The Ecotone Between Prairie And Woodland, R. J. Pool, J. E. Weaver, F. C. Jean

University Studies (University of Nebraska) (1888–1984)

A series of intensive investigations of the ecological features of the tension zone between prairie and woodland in the Mississippi valley was begun by Weaver and Thiel in 1915. These studies were continued for two seasons in Minnesota and were also extended to the prairies of eastern Nebraska in 1916. These investigations represent the first attempt to attack the prairie-forest problem on a comprehensive scale by means of the quantitative methods of modern ecology. Some of the results secured from these studies have been published as the first paper of a series planned to deal with critical investigations in the …


Synopsis Of The Conjugate Algae-Zygophyceae, Charles E. Bessey Jan 1914

Synopsis Of The Conjugate Algae-Zygophyceae, Charles E. Bessey

School of Biological Sciences: Faculty Publications

A dozen or more years ago the writer prepared a series of papers on these plants, which were published in volumes 21, 22 and 23 of these Transactions, and now it seems that time enough has elapsed to warrant another paper dealing with the same group, and including such revisions as are now made necessary because of our better knowledge of their structure, and the structure of the nearly related plants.


A Notable Botanical Career, Charles E. Bessey Jan 1914

A Notable Botanical Career, Charles E. Bessey

School of Biological Sciences: Faculty Publications

I have before me the " Report of the Botanist" to the Regents of the University of the State of New York, bearing date of January 1, 1868, covering less than two pages, and signed by Charles H. Peck. There is internal evidence that his services began July 1, 1867, the writer reporting what he had accomplished in the half year since that date. A year later the " Report of the Botanist " covered about 80 pages and included a short general statement followed by (A) List of Species of Which Specimens Have Been Mounted; (B) Plants Collected; (C) …


Rocky Mountain Flowers, Frederic E. Clements, Edith Schwartz Clements Jan 1914

Rocky Mountain Flowers, Frederic E. Clements, Edith Schwartz Clements

School of Biological Sciences: Faculty Publications

AN ILLUSTRATED GUIDE FOR PLANT-LOVERS AND PLANT-USERS WITH TWENTY-FIVE PLATES IN COLOR AND TWENTY-TWO PLATES IN BLACK AND WHITE

The present book is an endeavor to present the materials of the Rocky Mountain flora in preliminary form from the standpoint of the experimental ecologist. The latter is concerned primarily with the relationships of "species" and their subdivisions as an organic expression or measure of habitat differences, and of the competitive relations of the various formations. Whatever the taxonomic value of the numerous segregates of the last decade or two, the fact that the binomial form conceals the relationship to the …


Some Of The Next Steps In Botanical Science, Charles E. Bessey Jan 1913

Some Of The Next Steps In Botanical Science, Charles E. Bessey

School of Biological Sciences: Faculty Publications

When one who has worked long in any

field of science speaks before an audience

such as this he is expected to say something

about the condition of his branch of science

when he began work with meager and

poorly adapted apparatus, to contrast it

with its greatly improved condition to-day,

and to dwell with pride upon the finely

equipped laboratories with costly apparatus

especially designed for particular

experiments, to be found by the twentieth

century scientific student. And 1 must

confess that the temptation to do so was

one difficult to resist, for we who have

grown old in …


New Elementary Agriculture, Charles E. Bessey, Lawrence Bruner, Goodwin D. Swezey Jan 1911

New Elementary Agriculture, Charles E. Bessey, Lawrence Bruner, Goodwin D. Swezey

School of Biological Sciences: Faculty Publications

This is an agricultural nation. The products of the soil are the basis of her industries and her prosperity. The children of our great Commonwealths should be familiar with our crops, our grains and grasses, our flowers and fruits, our trees and shrubs and weeds, our domestic animals and birds and insects. Our children should have a practical knowledge of the management of a farm, of the composition of the soil, and of the adaptability of the farm and its soil for the cultivation of certain plants and the counter effect of such plant growth upon the soil. They should …


Botanical Teaching, Charles E. Bessey Jan 1911

Botanical Teaching, Charles E. Bessey

School of Biological Sciences: Faculty Publications

Some months ago a suggestion was made that at this dinner we should ask ourselves the question: Why is it that with the enormous classes we are having in botany there is a marked dearth of properly trained men who can serve as instructors in colleges and universities?


The Relation Of Leaf Structure To Physical Factors, Edith Schwartz Clements Jan 1905

The Relation Of Leaf Structure To Physical Factors, Edith Schwartz Clements

School of Biological Sciences: Faculty Publications

The leaf, as the seat of important physiological functions of the plant, and because of its modification by external factors, has long been a fruitful subject for investigation. As a rule, however, investigators have confined themselves solely to the histology and morphology of the leaf, independent of its relations to physical factors. Where the latter have been considered at all, it has been in a more or less general way, or undue importance has been assigned to one or another of the physical factors, and others have been ignored entirely. In no case have they been carefully measured. The aim …


The Grasses Of Nebraska, Charles E. Bessey, Robert Bolin , Depositor Jan 1905

The Grasses Of Nebraska, Charles E. Bessey, Robert Bolin , Depositor

School of Biological Sciences: Faculty Publications

Dr Bessey was the Nebraska State Botanist and Professor of Botany at University of Nebraska. This report contains a classification list of grasses found in the state and brief comments on the usefulness of the various grasses.


The Distribution Of The Native Forest Trees Of Nebraska, Charles E. Bessey, Robert Bolin , Depositor Jan 1904

The Distribution Of The Native Forest Trees Of Nebraska, Charles E. Bessey, Robert Bolin , Depositor

School of Biological Sciences: Faculty Publications

This document lists 67 trees identified by Dr Bessey with the help of others around the state. It includes the common and scientific names as well brief comment about each tree. Small maps are provided showing the distribution of each tree.