bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the Putative Type III Secretion ATPase CdsN (Cpn0707) ofChlamydophila pneumoniae
Authors: Stone Chris B. , Johnson Dustin L. , Bulir David C. , Gilchrist Jodi D. , Mahony James B.
Published: August 2008

Type III secretion (T3S) is utilized by a wide range of gram-negative bacterial pathogens to allow the efficient delivery of effector proteins into the host cell cytoplasm through the use of a syringe-like injectisome.Chlamydophila pneumoniaeis a gram-negative, obligate intracellular pathogen that has the structural genes coding for a T3S system, but the functionality of the system has not yet been demonstrated. T3S is dependent on ATPase activity, which catalyzes the unfolding of proteins and the secretion of effector proteins through the injectisome. CdsN (Cpn0707) is predicted to be the T3S ATPase ofC. pneumoniaebased on sequence similarity to other T3S ATPases. Full-length CdsN and a C-terminal truncation of CdsN were cloned as glutathioneS-transferase (GST)-tagged constructs and expressed inEscherichia coli. The GST-tagged C-terminal truncation of CdsN possessed ATPase activity, catalyzing the release of ADP and Pifrom ATP at a rate of 0.55 ± 0.07 μmol min−1mg−1in a time- and dose-dependent manner. CdsN formed oligomers and high-molecular-weight multimers, as assessed by formaldehyde fixation and nondenaturing polyacrylamide gel electrophoresis. Using bacterial two-hybrid and GST pull-down assays, CdsN was shown to interact with CdsD, CdsL, CdsQ, and CopN, four putative structural components of theC. pneumoniaeT3S system. CdsN also interacted with an unannotated protein, Cpn0706, a putative CdsN chaperone. Interactions between CdsN, CdsD, and CopN represent novel interactions not previously reported for other bacterial T3S systems and may be important in the localization and/or function of the ATPase at the inner membrane ofC. pneumoniae.
The
yiaKLX1X2PQRS
and
ulaABCDEFG
Gene Systems Are Required for the Aerobic Utilization of
l
-Ascorbate in
Klebsiella pneumoniae
Strain 13882 with
l
-Ascorbate-6-Phosphate as the Inducer
Authors: Campos Evangelina , de la Riva Lucia , Garces Fernando , Giménez Rosa , Aguilar Juan , Baldoma Laura , Badia Josefa
Published: August 2008

The capacity to both ferment and oxidize
l
-ascorbate has been widely documented for a number of enteric bacteria. Here we present evidence that all the strains of
Klebsiella pneumoniae
tested in this study ferment
l
-ascorbate using the
ula
regulon-encoded proteins. Under aerobic conditions, several phenotypes were observed for the strains. Our results showed that the
yiaK-S
system is required for this aerobic metabolic process. Gel shift experiments performed with UlaR and YiaJ and probes corresponding to the specific promoters indicated that
l
-ascorbate-6-phosphate is the effector molecule recognized by both regulators, since binding of the repressors to their recognition sites was impaired by the presence of this compound. We demonstrated that in
K. pneumoniae
cells
l
-ascorbate-6-phosphate is formed only by the action of the UlaABC phosphotransferase system. This finding explains why strains that lack the
ula
genetic system and therefore are unable to form the inducer intracellularly cannot efficiently use this vitamin as a carbon source under either anaerobic or aerobic conditions. Thus, efficient aerobic metabolism of
l
-ascorbate in
K. pneumoniae
is dependent on the presence of both the
yiaK-S
and
ula
systems. The expression of the
yiaK-S
operon, but not the expression of the
ula
regulon, is controlled by oxygen availability. Both systems are regulated by the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex and by IHF.
Accelerated Prion Disease Pathogenesis in Toll-Like Receptor 4 Signaling-Mutant Mice
Authors: Spinner Daryl S. , Cho In Soo , Park Seung Yong , Kim Jae Il , Meeker Harry C. , Ye Xuemin , LaFauci Giuseppe , Kerr Daniel J. , Flory Michael J. , Kim Bo Sook , Kascsak Regina B. , Wisniewski Thomas , Levis William R. , Schuller-Levis Georgia B. , Carp Richard I. , Park Eunkyue , Kascsak Richard J.
Published: August 2008

Prion diseases such as scrapie involve the accumulation of disease-specific prion protein, PrPSc, in the brain. Toll-like receptors (TLRs) are a family of proteins that recognize microbial constituents and are central players in host innate immune responses. The TLR9 agonist unmethylated CpG DNA was shown to prolong the scrapie incubation period in mice, suggesting that innate immune activation interferes with prion disease progression. Thus, it was predicted that ablation of TLR signaling would result in accelerated pathogenesis. C3H/HeJ (Tlr4Lps-d) mice, which possess a mutation in the TLR4 intracellular domain preventing TLR4 signaling, and strain-matched wild-type control (C3H/HeOuJ) mice were infected intracerebrally or intraperitoneally with various doses of scrapie inoculum. Incubation periods were significantly shortened in C3H/HeJ compared with C3H/HeOuJ mice, regardless of the route of infection or dose administered. At the clinical phase of disease, brain PrPSclevels in the two strains of mice showed no significant differences by Western blotting. In addition, compared with macrophages from C3H/HeOuJ mice, those from C3H/HeJ mice were unresponsive to fibrillogenic PrP peptides (PrP residues 106 to 126 [PrP106-126] and PrP118-135) and the TLR4 agonist lipopolysaccharide but not to the TLR2 agonist zymosan, as measured by cytokine production. These data confirm that innate immune activation via TLR signaling interferes with scrapie infection. Furthermore, the results also suggest that the scrapie pathogen, or a component(s) thereof, is capable of stimulating an innate immune response that is active in the central nervous system, since C3H/HeJ mice, which lack the response, exhibit shortened incubation periods following both intraperitoneal and intracerebral infections.
The C Terminus of Foamy Retrovirus Gag Contains Determinants for Encapsidation of Pol Protein into Virions
Authors: Lee Eun-Gyung , Linial Maxine L.
Published: August 2008

Foamy viruses (FV) differ from orthoretroviruses in many aspects of their replication cycle. A major difference is in the mode of Pol expression, regulation, and encapsidation into virions. Orthoretroviruses synthesize Pol as a Gag-Pol fusion protein so that Pol is encapsidated into virus particles through Gag assembly domains. However, as FV express Pol independently of Gag from a spliced mRNA, packaging occurs through a distinct mechanism. FV genomic RNA contains
cis
-acting sequences that are required for Pol packaging, suggesting that Pol binds to RNA for its encapsidation. However, it is not known whether Gag is directly involved in Pol packaging. Previously our laboratory showed that sequences flanking the three glycine-arginine-rich (GR) boxes at the C terminus of FV Gag contain domains important for RNA packaging and Pol expression, cleavage, and packaging. We have now shown that both deletion and substitution mutations in the first GR box (GR1) prevented neither the assembly of particles with wild-type density nor packaging of RNA genomes but led to a defect in Pol packaging. Site-directed mutagenesis of GR1 indicated that the clustered positively charged amino acids in GR1 play important roles in Pol packaging. Our results suggest that GR1 contains a Pol interaction domain and that a Gag-Pol complex is formed and binds to RNA for incorporation into virions.
A Genetic Interaction between Hepatitis C Virus NS4B and NS3 Is Important for RNA Replication
Authors: Paredes Anne M. , Blight Keril J.
Published: August 2008

Hepatitis C virus (HCV) nonstructural protein 4B (NS4B), a poorly characterized integral membrane protein, is thought to function as a scaffold for replication complex assembly; however, functional interactions with the other HCV nonstructural proteins within this complex have not been defined. We report that a Con1 chimeric subgenomic replicon containing the NS4B gene from the closely related H77 isolate is defective for RNA replication in a transient assay, suggesting that H77 NS4B is unable to productively interact with the Con1 replication machinery. The H77 NS4B sequences that proved detrimental for Con1 RNA replication resided in the predicted N- and C-terminal cytoplasmic domains as well as the central transmembrane region. Selection for Con1 derivatives that could utilize the entire H77 NS4B or hybrid Con1-H77 NS4B proteins yielded mutants containing single amino acid substitutions in NS3 and NS4A. The second-site mutations in NS3 partially restored the replication of Con1 chimeras containing the N-terminal or transmembrane domains of H77 NS4B. In contrast, the deleterious H77-specific sequences in the C terminus of NS4B, which mapped to a cluster of four amino acids, were completely suppressed by second-site substitutions in NS3. Collectively, these results provide the first evidence for a genetic interaction between NS4B and NS3 important for productive HCV RNA replication.
Revision 2: an immunohistochemical approach and evaluation of solid pseudopapillary tumour of the pancreas
Authors: Serra S , Chetty R
Published: August 2008

Solid pseudopapillary tumours (SPT) of the pancreas are uncommon, but with widespread and increased imaging, several of these lesions are coming to light incidentally and are subject to needle biopsies. On limited material and especially the solid or clear cell, variants of SPT can morphologically mimic most notably pancreatic neuroendocrine tumours and even metastatic renal cell carcinoma or melanoma. In this context, immunohistochemistry is important and useful in helping to reach the correct diagnosis. Several antibodies have been used in the immunohistochemical evaluation of SPT. As with most tumours, no one marker is specific, but rather a core panel is advocated. Recently, both β-catenin and E-cadherin have been shown to be of value in SPT. Nuclear and cytoplasmic decoration of tumour cells by β-catenin is seen in almost 100% of cases. This protein relocalisation away from the cell membrane is underscored by mutations of theβ-cateningene. Mutations of theCDH1gene are very uncommon in SPT, but the immunohistochemically detected changes to the protein are consistent and present in 100% of cases. Using an E-cadherin antibody to the extracellular domain of the molecule results in complete membrane loss, while the antibody directed to the cytoplasmic fragment produces distinct nuclear staining of the tumour cells. In addition, there is concordance of staining abnormalities between the two antibodies. When combined with CD10 and progesterone receptor positivity, a diagnosis of SPT can be rendered with confidence even in small biopsy samples.
A SURVEY OF HIGHER PLANTS FOR ANTIBACTERIAL SUBSTANCES
Authors: Bishop Charles J. , MacDonald Russell E.
Published: August 2008

The results of a preliminary survey of 209 Nova Scotian plants are reported. In the survey five solvents: distilled water, alcohol, ether, acetone, and benzene were used to extract substances from each plant. By the use of these solvents, 33.4% of the plants tested were shown to contain one or more substances inhibitory to Staphylococcus aureus No. 209 and/or Escherichia coli A.T.C.C. No. 9637. Fifteen per cent of the extractions made showed activity against S. aureus, while 4.6% were active against E. coli. The highest incidence of activity was obtained with the ether extractions. All the plants tested are listed, and those displaying any activity are tabulated with their results. The 10 most active plants were found to be: Cirsium arvense, Chimaphila umbellata, Eupatorium perfoliatum, Menyanthes trifoliata, Monotropa uniflora, Myrica Gale, Nymphaea odorata, Oxalis europaea, Populus gileadensis, and Pyrus Malus.
STUDIES ON FUNGUS PARASITES OF STRAWBERRY LEAVES IN ONTARIO
Authors: Fall Joan
Published: August 2008

Four fungi were isolated from lesions on strawberry foliage in Ontario during the growing seasons of 1948 and 1949. They are Mycosphaerella fragariae (Tul.) Lindau. Diplocarpon carliana (Ell. & Ev.) Wolf, Dendrophoma obscurans (Ell. & Ev.) H. W. And., and Gnomonia fructicola (Arnaud) n. comb. (Zythia fragariae Laibach), and they cause the diseases known as leaf spot, leaf scorch, leaf blight and leaf blotch respectively. Apparently this is the first report of Zythiae fragariae in North America and of Dentrophoma obscurans in Canada. From field surveys, strawberry varieties were found to vary in resistance, especially to spot and scorch, and market differences in seasonal distribution of the diseases were also evident. Spot was most prevalent in the spring and fall; scorch increased in severity during the warmer months; and blight became prominent after the cropping period. As a result of inoculation with M. fragariae only the middle-aged leaves of vigorously growing strawberry plants developed lesions. Premier plants, although resistant to spot in the field, proved susceptible when artificially inoculated. Penetration by M. fragariae may occur without lesion formation if the temperature is below 15 °C. Symptom expression was best within the 20°–25 °C range. Adding strips of strawberry leaves to a suspension of conidia of Diplocarpon earliana greatly enhanced spore germination. Only leaves which are old or middle-aged develop scorch lesions, and these may be blotchy or diffuse depending on the variety. Dendrophoma obscurans appears to attack mainly the older leaves near the margins. The conidiophores are long and branched, the conidia slightly pointed, and the pyenidia are dark, leathery, and clumped in culture. Zythia fragariae has simple conidiophores, biguttulate conidia with rounded ends, and soft light brown pyenidia. The name Gnomonia fructicola is proposed for the fungus Gnomonia fragariae Klebahn form fructicola Arnaud because it is considered to be a different species from Gnomonia fragariae Klebahn.
PHYSIOLOGICAL AND BIOCHEMICAL STUDIES IN PLANT METABOLISM: III. THE EFFECTS OF STARVATION AND MECHANICAL STIMULATION ON THE RESPIRATORY METABOLISM OF THE FIRST LEAF OF THE WHEAT PLANT
Authors: Roberts D. W. A.
Published: August 2008

The oxygen uptake and carbon dioxide output records of detached starving first leaves of wheat have been investigated. Small changes in the oxygen tension or carbon dioxide tension of the surrounding air do not make any difference in the records. The data obtained with the Barcroft method agree with those obtained by the Pettenkofer method. The form of the starvation air line is described. It is generally similar in the four quarters of the leaf but the senescent hump of the basal quarter is much flatter and its peak much lower than in the other three quarters. The total senescent hump carbon dioxide is shown to be proportional to the protein nitrogen in each of the four quarters. The effect on the air lines of rubbing and quartering the leaves is described. There is a great temporary increase in carbon dioxide output as a result of rubbing. This quickly subsides and the respiration rate after the rubbing settles down to a value slightly in excess of that prior to the rubbing. Rubbing and quartering have no effect on the R.Q. of the starving leaves.
THE ANNUAL CYCLE OF SIZE CHANGES IN THE FUSIFORM CAMBIAL CELLS OF CHAMAECYPARIS AND THUJA
Authors: Bannan M. W.
Published: August 2008

In stems exceeding a few inches in diameter most of the pseudotransverse divisions involved in the multiplication of fusiform cambial cells occur toward the end of the growing season. Often these aestival transverse divisions are immediately followed by extensive elongation of the new-formed cambial Cells, especially at their overlapping tips. In the succeeding year relatively slight elongation ensues during the development of the first quarter of the annual ring, but through the succeeding quarters the amount of extension increases and is usually maximal in the final quarter. The actual rates of elongation remain undetermined. The multiplication of fusiform initials is accompanied by loss, most of the failure taking place during the last quarter. Generally the fusiform initials with the most extensive ray contacts survive and enlarge, and those with poor ray associations fail or are reduced to potential ray initials. The elongation and multiplication of fusiform initials tend to produce local ray deficiencies. Reduction of the fusiform initials with the poorest ray contacts to ray initials rectifies to varying extent the ray shortages in those areas.
STUDIES IN FOREST PATHOLOGY: VIII. DECAY OF WESTERN HEMLOCK ON THE QUEEN CHARLOTTE ISLANDS, BRITISH COLUMBIA
Authors: Foster R. E. , Foster A. T.
Published: August 2008

An investigation of western hemlock (Tsuga heterophylla (Raf.) Sarg.) on the Queen Charlotte Islands, British Columbia, has shown that decay losses in old-growth stands are appreciable, amounting to 13.9, 8.0, and 10.7% of the gross volume of Grades 1, 2, and 3 logs respectively. Total loss, including dead trees, amounted to 25.5% of the gross volume. Twenty-seven decay-producing fungi have been isolated. The most important of these are Fomes pinicola (Sw.) Cke., F. pini (Thore) Lloyd, F. annosus (Fr.) Cke., and Polyporus sulphureus Bull. ex Fr. Echinodontium tinctorium E. & E. apparently does not occur in the region. Scars provided the most frequent, and roots the most important, avenue of entrance for decay. The logs of 2318 western hemlock were analyzed in detail. Decay was found to increase progressively with diameter, age, and decreasing site quality. Maximum net periodic increment was reached between 350 and 400 years of age and between 35 and 40 in. in diameter. Color of bark was found to provide an added indication of tree maturity. Understory trees were found to give a substantial yield of sound wood.
Identification of Pathogenic Fish Bacteria Using the API ZYM System
Authors: Sakai Masahiro , Soliman M. K. , Yoshida T. , Kobayashi Masanori
Published: August 2008

The API ZYM system was used to identify the bacterial fish pathogens Enterococcus seriolicida, β-hemolytic Streptococcus sp., Renibacterium salmoninarum, Aeromonas salmonicida, A. hydrophila, Pasteurella piscicida, Edwardsiella tarda, Vibrio anguillarum, Pseudomonas fluorescens, Flexibacter columnaris, and F. maritimus. As additional tests, Gram stain and the activities of cytochrome oxidase and catalase were examined. The results of APS ZYM and the additional tests were coded for easy identification. Several biotypes were demonstrated by Streptococcus sp., V. anguillarum, and A. hydrophila. Other bacteria showed uniform profiles. This system can distinguish each fish pathogen from all other bacterial species examined.
Effects of Ammonium and Nitrate on Growth and Domoic Acid Production by Nitzschia pungens in Batch Culture
Authors: Bates Stephen S. , Worms Jean , Smith John C.
Published: August 2008

Four clones of Nitzschia pungens f. multiseries (toxin-producing form) and two of N. pungens f. pungens (nontoxic) were grown in batch culture at initial nitrogen concentrations of 55, 110, 220, 440, and 880 μM in the form of either nitrate or ammonium. As expected, only N. pungens f. multiseries clones produced the neurotoxin, domoic acid (DA). Ammonium at 880 μM prevented the growth of all N. pungens clones but not of Skeletonema costatum, although division rate was reduced. At 440 μM, ammonium lowered the cell yield obtained during the stationary phase, inhibited photosynthesis, and caused a lag phase during which DA was produced (by f. multiseries). At 220 and 440 μM ammonium, in contrast with the same concentrations of nitrate, stationary phase cellular DA production was enhanced by two- to fourfold. At 110 and 55 μM nitrogen, cell yield and DA production were equivalent for nitrate and ammonium but less DA was produced relative to the higher nitrogen concentrations, possibly due to nitrogen depletion. Enhanced production of DA at elevated ammonium concentrations may be a response to ammonia toxicity. This could be a useful tool for studying mechanisms of DA production and for maximizing the yield of this valuable toxin in large-scale cultures.
Metal-induced facile synthesis of a tricyclic system — 10-Methyl-12-thia-2,9-diaza-tricyclo[8.3.1.03,8]tetradeca-3,5,7-triene-1-carbonitrile. Formation of an intramolecular carbon–carbon bond
Authors: Tandon Santokh S , Lucas C Robert
Published: August 2008

The reaction between 4-thiaheptane-2,6-dione and 1,2-diaminobenzene in the presence of nickel(II) perchlorate results in the formation of a nickel(II) complex of a novel new heterotricyclic system: 1-methoxy-10-methyl-12-thia-2,9-diaza-tricyclo[8.3.1.03,8]tetradeca-3,5,7-triene, which on treatment with potassium cyanide gives 10-methy-12-thia-2,9-diaza-tricyclo[8.3.1.03,8]tetradeca-3,5,7-triene-1-carbonitrile, a case of metal-induced carbon–carbon bond formation.Key words: nickel-induced carbon–carbon bond formation, intramolecular cyclization, tricyclic formation.
Strategic efficiency — The new thrust for synthetic organic chemists
Authors: Qiu Fayang
Published: August 2008

A standard for gauging the efficiency of synthetic strategies has been proposed. Synthetic efficiency is correlated to the molecular-complexity index, which is the cumulative total number of chiral centers, independent functional groups, and rings contained in a molecule. The number of reaction steps for an efficient synthetic design must be smaller than that of molecular-complexity index. This standard will motivate organic chemists to work harder on the synthetic design prior to execution.Key words: strategic efficiency, total synthesis, synthetic design, complexity index.
Variations in energy content of some carabid beetles in eastern Canada
Authors: Randolph J. C. , Randolph P. A. , Barlow C. A.
Published: August 2008

Five species of adult carabid beetles were collected weekly from meadow and deciduous forest habitats in eastern Canada during the snow-free part of the year and analyzed for relative abundance, weight, and caloric equivalent. Although the same species were collected in both habitats, the deciduous forest had a greater relative abundance. Within a species the individual dry weights of male and of female beetles without ova are not different, but with increasing numbers of ova some reproductive females are twice as heavy as males. Significant differences in caloric equivalents (cal/ash-free g dry wt.) were found between species and between gravid females and males or non-gravid females within a species. Abundances, weights of individuals, and caloric equivalents all contribute to variations in energy content. However, comparisons of several estimates of total beetle energy content using data with varying levels of resolution suggest that detailed calorific analysis may not be necessary for population level studies.
Ultrastructural studies on the cuticle of the second-stage larvae of four root-knot nematodes: Meloidogyne hapla, M. javanica, M. incognita, and M. arenaria
Authors: Johnson P. W. , Graham W. G.
Published: August 2008

Ultrastructural studies on the cuticle of the second-stage larvae of Meloidogyne hapla, M. javanica, M. incognita, and M. arenaria showed that the cuticle structure in all four species was similar and consisted of six layers divisible into three zones: an outer trilaminate cortex, a two-layered median zone, and a basal striated zone. No association could be established between the structure of the cuticle of L2 M. hapla and the ability of the nematode to survive freezing temperatures significantly better than L2 M. incognita.
Fine structure of surface and sunken grooved pegs on the antenna of female Anopheles stephensi (Diptera: Culicidae)
Authors: Boo K. S. , McIver S. B.
Published: August 2008

The antenna of female Anopheles stephensi Liston bears three types of sensilla with grooved pegs: those sunken in pits and subtypes A and B of those located on the flagellar surface. The sunken peg sensilla are innervated by four or five neurons with branching dendrites. The dendrites are exposed to the exterior by means of longitudinal clefts at the bases of the grooves in the peg wall. Surrounding the dendrites and extending into the clefts is an extracellular material of medium electron density. Three sheath cells are associated with each sunken peg sensillum.Subtype-A surface peg sensilla are generally similar to the sunken peg sensilla, except that they are located on the antenna) surface and are innervated by two neurons with unbranched dendrites. Subtype-B surface peg sensilla have three or four neurons, the dendrites of which do not branch and are exposed less to the exterior than those in the other peg sensilla because the clefts in the peg wall are smaller and less frequent. Only trace amounts of electron-dense material occur in the clefts of the subtype-B surface peg sensilla.The sunken peg and both subtypes of the surface peg sensilla are probably olfactory receptors.
Influence of injection route on radiothyroxine kinetics in brook trout, Salvelinus fontinalis (Mitchill)
Authors: Higgs D. A. , Eales J. G.
Published: August 2008

Groups of starved yearling brook trout at 12 °C were injected with 125I-labelled thyroxine (*T4) into the heart, coelom, or dorsal musculature. Disappearance of plasma-protein-bound radioactivity was described by fast and slow exponents. The fast exponent representing *T4 loss was used to calculate T4 metabolic clearance rate (MCR). MCR values were 2.79 (heart), 2.96 (coelom), and 4.92 ml/h per 100 g (muscle). The slower turnover of *T4 in muscle-injected fish was accompanied by slower deiodination and enterohepatic excretion of *T4. Heart injection is recommended for routine *T4 kinetic studies in fish.
Helminths in moose of Alberta
Authors: Samuel W. M. , Barrett M. W. , Lynch G. M.
Published: August 2008

Sixteen species of helminths (five cestodes, eight nematodes, and three trematodes) were found during examination of 215 moose from Alberta. Different helminth faunas occurred in moose from the major population in the west and north, and from isolated populations in central (Elk Island National Park) and southeastern (Cypress Hills Provincial Park) Alberta; only Moniezia sp., Taenia hydatigena, and Nematodirella longispiculata were found in all three populations. Thysanosoma actinioides, Protostrongylus macrotis, Setaria labiatopapillosa, Fascioloides magna, and Zygocotyle lunata were found in only one of the three populations; their presence was most likely due to cohabitation by moose and other infected vertebrates. The presence of wolves probably accounted for the high prevalence of Echinococcus granulosus, T. hydatigena, and Taenia krabbei in the west and north, while coyotes were of local importance in maintenance of E. granulosus and T. hydatigena in the park populations. Wehrdikmansia cervipedis was not found in park populations probably because of absence or scarcity of the intermediate host. Moniezia expansa, P. macrotis, S. labiatopapillosa, and Z. lunata are reported for the first time from moose in North America.
The effects of estradiol and progesterone on the growth and differentiation of the quail oviduct
Authors: Boogaard C. L. , Finnegan C. V.
Published: August 2008

The effects of estradiol and progesterone treatment on the growth and differentiation of the quail oviduct have been investigated in terms of morphology, growth, and biochemical differentiation. Histologically, estradiol induced the formation of tubular gland cells by 5 days of treatment, and epithelial differentiation by 10 days of treatment. Progesterone treatment appeared to enhance epithelial differentiation slightly, compared with continued estrogen treatment. The estradiol treatment also enhanced the growth of the oviduct, as indicated by increases in size, weight, and the content of the tissue constituents protein, RNA, and DNA. Estradiol treatment also induced the synthesis of two specific proteins, ovalbumin and lysozyme; however, only progesterone induced the synthesis of the protein avidin. Withdrawal from both types of treatment for 10 days caused a loss of cells and of tissue constituents. This loss was greater in those birds withdrawn from sequential estrogen-plus-progesterone treatment than in those withdrawn from estrogen treatment. In some cases, specific proteins were also absent in oviducts from birds withdrawn from treatment.
Alteration of buoyancy by some Central American stream fishes, and a comparison with North American species
Authors: Gee John H. , Gee Phyllis A.
Published: August 2008

Of 23 species (nine families) of Central American fishes examined, nine (eight physostomes, one physoclist) did not reduce buoyancy by decreasing swim-bladder volume when current was encountered. The remainder (six physostomes, eight physoclists) decreased buoyancy, usually within 24–48 h, but three of these species (one physostome) were unable to maintain a reduced buoyancy for as long as 72 h once the minimum was achieved. All species have an excess internal pressure of swim-bladder gas. All of the North American species that have been studied do show a buoyancy alteration in response to changes in water current and adjust to a greater extent, although rates of adjustment appear similar to those of Central American fishes. Differences in flow regime between North and Central American streams are described and may partially account for these differences in reaction to water current.
The time–temperature relation of embryonic development in the northwestern salamander, Ambystoma gracile
Authors: Brown Herbert A.
Published: August 2008

A field and laboratory study on temperature-related embryonic development of Ambystoma gracile was made on a population from northwestern Washington. Natural spawning began in the beaver pond during early March, and the duration of embryonic development (stages 1 to 46) was about 62 days. Average water temperature in the pond during embryonic development was 8.5 °C (range, 4.4 to 14.3 °C). The laboratory data of embryonic development at constant temperatures show that the limits of temperature tolerance are about 5 to 22.5 °C. Rate of development was measured by determining time required to develop from first cleavage (stage 2) to gill circulation (stage 37); representative rates are 12.7 days at 20 °C, 27 days at 12 °C, and 89 days at 7 °C. Embryos of A. gracile have the slowest rate of development when compared with embryos of four other species of Ambystoma (maculatum, mexicanum, tigrinum, and jeffersonianum) and with embryos of three Pacific Northwest frogs (Ascaphus truei, Rana aurora, and Hyla regilla).
The development of nematode behaviour: stage-specific behaviour in Panagrellus redivivus
Authors: Pollock Carol , Samoiloff M. R.
Published: August 2008

Larvae of the free-living nematode Panagrellus redivivus differ from adults in their attraction to bacteria. Under osmotic stress larvae coil, while adults do not. Larvae do not travel as far, but undergo more looping, turning, and reversal activity than do normal adults. A behavioural mutant, corkscrew, with primary expression in adults, shows differences in behaviour at each stage of the life cycle.
Catalytic and regulatory properties of pyruvate kinase isozymes from octopus mantle muscle and liver
Authors: Guderley H. E. , Storey K. B. , Fields J. H. A. , Hochachka P. W.
Published: August 2008

The octopus is a relatively slow-moving animal that relies upon burst swimming to power its predatory activities. Pyruvate kinase (EC, 2.7.1.40), as one of the major glycolytic control sites, must be regulated in such a fashion to allow the increased glycolytic rate characteristic of burst metabolism. The mantle enzyme is regulated by the concerted action of ATP, arginine phosphate, and citrate. The Km for ADP was 0.28 mM and that for phosphoenolpyruvate (PEP), 0.25 mM. In contrast to many other invertebrate muscle pyruvate kinases, the enzyme is insensitive to fructose-1,6-diphosphate (FDP) activation.The pyruvate kinase from the liver is kinetically and electrophoretically distinct from the mantle enzyme. The liver isozyme has a considerably lower affinity for PEP (Km = 0.85 mM), is inhibited by ATP, citrate, and arginine phosphate, and is subject to a strong activation by FDP (Ka = 1 × 10−6). These differences between the pyruvate kinases from catabolic and synthetic tissues are reminiscent of the distinctions between mammalian muscle and liver pyruvate kinases.
Octopus mantle citrate synthase
Authors: Fields J. H. A. , Guderley H. , Storey K. B. , Hochachka P. W.
Published: August 2008

Citrate synthase (EC 4.1.3.7) in mantle muscle of the octopus, Octopus cyanea, occurs in relatively low specific activity and is largely independent of pH between 7.5 and 9.0. Catalytic activity is regulated by the adenylate energy charge and by at least two Krebs cycle intermediates, α-ketoglutarate and citrate. Of the adenylates, ATP is by far the most potent inhibitor, at near-physiological concentrations (4 mM), causing almost a 20-fold increase in the Michaelis constant for acetyl-CoA. Citrate and α-ketoglutarate, on the other hand, are competitive with respect to oxaloacetate, rather than acetyl-CoA, and bring about large increases in the Michaelis constant for oxaloacetate. The regulatory properties of citrate synthase allow a curtailment of carbon flow into the Krebs cycle during periods of burst muscle work, when mantle anaerobic glycolysis is strongly activated.
Oyster citrate synthase: control of carbon entry into the Krebs cycle of a facultative anaerobe
Authors: Fields J. H. A. , Hochachka P. W.
Published: August 2008

Citrate synthase (EC 4.1.3.7) in adductor muscle of the oyster, Crassostrea gigas, occurred in relatively low specific activity, about 1.5 μmol product formed per minute per gram wet weight of tissue. The enzyme activity was essentially independent of pH between pH 7.5 and 9.0. The Km values for acetyl-CoA and oxaloacetate were about 0.005 mM in each case. Catalytic activity was modulated by the adenylates, citrate, and 2-ketoglutarate, all of which were inhibitory. The regulatory properties of the enzyme suggest that during the transition to anoxia oxaloacetate becomes limiting, thus reducing flux through the initial stages of the Krebs cycle.
The perineal gland of brown lemmings, Lemmus trimucronatus
Authors: Stewart R. E. A. , Brooks R. J.
Published: August 2008

In adult male brown lemmings, Lemmus trimucronatus, a specialized pad of sebaceous glands forms the perineal gland, consisting primarily of two longitudinal ridges lateral and parallel to the midventral line of the scrotum. The ridges extend from the posterior margin of the penis sheath to the anterior edge of the rectum, and correspond externally with a pair of longitudinal furrows. Externally, the gland is characterized by brown pigmentation and coarse, transparent hairs. Histologically it is comparable to, though larger than, the rump gland of the same species. Development of the perineal gland is correlated with attainment of sexual maturity.On the basis of other studies analogous skin glands in other rodents, a scent-producing function is hypothesized for the perineal gland.
An ultrastructural study of the head region of bovine spermatozoa
Authors: Oko R. J. , Costerton J. W. , Coulter G. H.
Published: August 2008

Differential interference micrographs, electron micrographs of thin sections, and electron micrographs of freeze-etched preparations have been used in a coordinated study of the head structure of bovine spermatozoa. The equatorial segment can be visualized by all three methods but it is more clearly defined in aged cells in which the plasmalemma covering the apical region is loosened. The thinning of the acrosome in the equatorial segment allows the penetration of postnuclear-cap material both into the subacrosomal space and into the transition zone between the acrosome and the plasmalemma to produce an 'overlap' structure in this region.The plasmalemma cleaves predominantly in the median hydrophobic zone and this cleavage plane is both distorted by underlying structures and physically modified by its apposition to these structures. These physical modifications are reflected in the formation of 'plaques' by departures from the median cleavage plane in some areas and in the arrangements of globular particles, which are equated with protein complexes. Rings of globular particles within the cleavage plane of the plasmalemma are coincident with underlying nuclear pores in the diverticula. The median cleavage of the outer acrosomal membrane exposes numerous globular particles in linear arrays. Spiralized linear structures resembling microtubules are seen in the postnuclear cap.
On the purification of a fatty acid synthetase complex from an insect
Authors: Thompson S. N. , Barlow J. S.
Published: August 2008

The fatty acid synthetase complex of the blowfly, Lucilia sericata, catalyzing the de novo synthesis of fatty acids from acetyl- and malonyl-CoA (EC 2.3.1.9 and EC 2.3.1.39 respectively) and requiring NADPH, was isolated from whole-insect homogenates by ultracentrifugation. Purification was carried out by salt fractionation, anion exchange column chromatography on ECTEOLA (epichlorohydrin triethanolamine) cellulose, and gel filtration column chromatography on Sephadex®.
Responses of Myotis lucifugus (Chiroptera: Vespertilionidae) to calls of conspecifics and to other sounds
Authors: Fenton M. B. , Belwood J. J. , Fullard J. H. , Kunz T. H.
Published: August 2008

We played a variety of sounds to Myotis lucifugus occupying a New Hampshire barn in August 1975 using a recording and playback system which reproduced sounds from 15 to over 100 kHz. The M. lucifugus responded to 'distress' calls of conspecifics but not to other noises, specifically feeding sounds of Myotis spp., continuous 45 kHz sound, and 'distress' cries of Eptesicusfuscus. Responses to the 'distress' cries of conspecifics included general increases in levels of activity and low-frequency vocalizations (audible to us), and swooping flights near the ultrasonic loudspeaker from which the sounds eminated. When a dead M. lucifugus was suspended above the speaker and the 'distress' calls of this species were presented, bats circled close to the carcass; they did not respond in this way when other sounds were presented or during controls when the carcass was present.
Observations on the movements and structure of the bursa of Nippostrongylus brasiliensis and Nematospiroides dubius
Authors: Croll N. A. , Wright K. A.
Published: August 2008

There is growing evidence of the autonomy of the movements of certain organ systems in nematodes. The copulatory bursa of male strongylines is believed to aid in mating, although there arc very few reports of this. Furthermore, it has been suggested that movements of the bursa are stimulated by a pheromone secreted by the female. Bursal movements were investigated with respect to these themes and the fine structure of the bursa of Nippostrongylus brasiliensis was examined. When the bursa was ligatured and isolated from the body, bursal movements of N. brasiliensis and Nematospiroides dubius were greatly increased for extended periods. The movements showed rhythmic pacemaker activity and they simulated the movements observed in the normal mating of N. dubius. The bursa of N. brasiliensis was found to have muscular and sensory elements, a nerve was shown to be present in both spicules, and sensory elements were located in the genital cone. The increase in movements is believed to result from the removal of an inhibitor associated with the circumpharyngeal commissure. These results are discussed in terms of other observations on control mechanisms in nematodes and their functional morphology.
Fates of disappearing individuals in fluctuating populations of Microtus townsendii
Authors: Hilborn Ray , Krebs Charles J.
Published: August 2008

Fates of disappearing individuals were determined for two natural populations of Microtus townsendii by livetrapping of evacuated areas and marginal habitat, and by marking individuals with radioactive tags to locate carcasses. Two hundred and nineteen out of the 454 individuals that disappeared were radioactively tagged during this 3-year study conducted in the University of British Columbia Research Forest near Haney, B.C. Only 30 radioactive tags were recovered on the live-trapping areas. Most disappearances in this vole population must have been caused by dispersal or predation.Most disappearance from increase and peak populations was due to dispersal. Two summer periods of declining numbers were observed; during one such period many individuals' remains were found on the study areas, but during the other period of declining numbers few remains were found. There was no increase in dispersal rate as measured by the above techniques during either decline period. It is concluded that during the first brief period of declining numbers individuals were dying in their nests from physical factors associated with a severe summer drought and during the second period of declining numbers individuals were either moving long distances without going into traps or being taken by predators.
Recent limnological changes in southern Kootenay Lake, British Columbia
Authors: Cloern James E.
Published: August 2008

In response to a significant abatement of phosphate loading and the construction of a dam on its major inflow (the Kootenay River), southern Kootenay Lake experienced a number of limnological changes between 1969 and 1974. Water temperatures in 1974–1975 were similar to those previously reported for 1966–1969. However, water transparency has increased, particularly during the spring months.Nitrate concentrations have remained unchanged since 1969, and ranged from 2 to 8 μM between 6 June 1974 and 22 May 1975. However, ammonium levels have been reduced in the winter months when mean concentration was about 1 μM. Dissolved phosphorus levels in 1966–1969 were consistently around 3 μM, but never reached 1 μM in 1974. Phytoplankton populations in 1974–1975 (measured as chlorophyll a) were lower than those during the 1966–1969 period, and evidence is presented that suggests that major shifts have occurred in the species composition of the phytoplankton. Whereas Kootenay Lake experienced blue–green and green algal blooms during the 1960's, no such phenomena were observed in 1974–1975 when the plankton was dominated by diatoms. Population maxima of the three most common zooplankters (Cyclops bicuspidatus, Diaptomus ashlandi, and Diaphanosoma leuchtenbergianum) have increased since 1966–1969.
Foraging behavior, learning, and exploration by captive ovenbirds (Aves: Parulidae)
Authors: Zach Reto , Falls J. Bruce
Published: August 2008

Captive ovenbirds (Seiurus aurocapillus) were individually exposed in a field arena to a patchy food supply. In experiment 1, involving a single patch, birds quickly concentrated their foraging in the patch. Equal amounts of food were taken at different prey densities and amount of search path per visit did not vary. However, number of visits to the patch and amount of search path per prey found decreased as patch density increased. Conversely, speed of search increased with patch density. Exploratory search (outside the patch) was reduced at higher prey densities suggesting that, with low depletion and high renewal rates, a single profitable feeding site may be sufficient. When tested a day later, birds went directly to the old patch location, now devoid of food, and searched it thoroughly. Learning was reflected in both the distribution and tortuosity of search paths. In experiment 2, involving two successively presented patches, birds rapidly concentrated their search effort in the new patch location and ignored the old location after an initial visit. Experiment 3, involving two simultaneously presented patches, demonstrated that birds can learn at least two patch locations and that search effort exerted in these locations after prey are removed may relate to previous profitabilities.
Territoriality, habitat selection, and prior residency in underyearling Stichaeus punctatus (Pisces: Stichaeidae)
Authors: Brown Joseph , Green John M.
Published: August 2008

Laboratory and field experiments showed that underyearling Stichaeus punctatus are territorial, select a particular type of habitat, and exhibit the prior residency effect. Territories are established immediately after settlement from the plankton. Although underyearlings disappeared from the study area in November, laboratory data suggested that S. punctatus are territorial for the first year of their benthic life. It is hypothesized that territoriality in underyearlings could result in selection for early settlement and may account for the relatively short period during which settlement occurs.
Behaviour of subarctic red-backed voles (Clethrionomys gapperi athabascae)
Authors: Mihok Steve
Published: August 2008

Interactions between pairs of red-backed voles were observed in a neutral observation arena in the summer of 1975 at Heart Lake. Northwest Territories, Canada. Twenty–one behaviours were recorded for each vole and were simplified to six factors of behaviour: amicable, defensive, aggressive, avoidance, subordinate, and fighting. The behaviour of one vole towards another in a trial was classified into defensive, avoidance, amicable, and aggressive types by unweighted pair group method (UPGM) cluster analysis. It was possible to partially predict behaviour on the basis of individual parameters such as: sex, age, and reproductive condition. The relationship between individuals showed better predictability, although the behaviour of each individual was variable. Male–female encounters were generally amicable with the female being dominant. Female–female encounters were similar to male–male encounters; avoidance, defensive, and aggressive behaviour predominated. Dominant females were generally older or in a later stage of pregnancy. Dominant males did not represent any consistent trends in age, sexual maturity, or weight differences. Mutual avoidance was the most common type of interaction.
The effects of photoperiod and temperature on the release of prolactin from the pituitary gland of the goldfish, Carassius auratus L.
Authors: McKeown B. A. , Peter R. E.
Published: August 2008

A number of experiments were conducted to investigate the effects of photoperiod and temperature on prolactin release from the goldfish pituitary gland. Fish were acclimated to different photoperiods and temperatures, and also were subjected to a change in either of these two parameters after different acclimation conditions. Serum and pituitary samples were collected and analyzed by radioimmunoassay for prolactin levels. In other experiments samples for prolactin analysis were taken every 3 h intermittently over a period of 3 days from fish that were acclimated to different photoperiod and temperature conditions. Longer photoperiods and higher temperatures caused pituitary prolactin release. Serum prolactin changed on a circadian rhythm and the rhythm was modified depending on the length of the photoperiod.
The distribution of Chironomus (s.s.)? cucini (salinarius group) larvae (Diptera: Chironomidae) in Parry Sound, Georgian Bay, with particular reference to structural deformities
Authors: Hare Landis , Carter John C. H.
Published: August 2008

The results of a study of the macroscopic zoobenthos in Parry Sound, Georgian Bay, Ontario, suggest that the larvae of Chironomus (s.s.)? cucini (salinarius group), which are present only in the deep cool regions below the summer thermocline, are most abundant when their environment has been 'altered' as a result of the activities of man. Furthermore, when these 'alterations' reach a too intense level larvae in this and other chironomid taxa may exhibit morphological deformities.