bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurons Selective for Orientation and Binocular Disparity in the Visual Wulst of the Barn Owl (
Tyto alba
)
Authors: Pettigrew John D. , Konishi Masakazu
Published: October 2006

The visual response properties of single neurons in the owl's visual Wulst suggest that this forebrain structure is an analog of the mammalian visual cortex. Features in common with the cat and the monkey visual cortex include a precise topographic organization, a high degree of binocular interaction, and selectivity for orientation, direction of movement, and binocular disparity of straight-line contours.
Physiology of the Amino Acids
Authors: Van Slyke Donald D.
Published: October 2006

We have followed the amino acids from their entrance into the alimentary tract in the form of food proteins through the successive steps of digestion, absorption into the blood stream and passage from the blood stream into the tissues, where they are concentrated by some unknown mechanism to many times their concentration in the blood plasma. We have seen something of the way in which certain of the amino acids can be transformed into one another in the body or synthesized from ammonia and keto acids. However, we have had to admit that our bodies can form in such ways only about half of the different amino acids that are required, and that the other half must be made for us by plants, bacteria or other organisms which have greater synthetic powers than we. And finally we have seen something of the manifold fates of the amino acids after they have entered our tissues; how they may be destroyed and their nitrogenous parts turned into urea in the liver before it is possible to put them to their more specialized uses, how their carbon fractions can be used to form glucose, how they may sacrifice themselves to protect us from toxic products, how they can serve as source material for certain vitamins, hormones and other compounds with physiological functions still to be identified, and how finally those amino acids which are not deflected to these various fates may enter into the proteins of the tissues and become for a time parts of our living structures.
Coronary Arterial Smooth Muscle Contraction by a Substance Released from Platelets: Evidence That It Is Thromboxane A
2
Authors: Ellis Earl F. , Oelz Oswald , Roberts L. Jackson , Payne N. Ann , Sweetman Brian J. , Nies Alan S. , Oates JohnA.
Published: October 2006

When human platelets are aggregated by thrombin, material is released that rapidly contracts strips of spirally cut porcine coronary artery. Prevention of the contraction by indomethacin suggested mediation by a prostaglandin. The contraction produced by aggregating platelets was unlike those produced by prostaglandins E
2
, F
2α
, G
2
, or H
2
, but resembled that evoked by thromboxane A
2
, which is formed by platelets during aggregation.
Behavioral Fever in Newborn Rabbits
Authors: Satinoff Evelyn , McEwen G. N. , Williams B. A.
Published: October 2006

Rabbit pups, 12 to 72 hours old, did not develop a fever when injected intraperitoneally with a pyrogen and maintained at an ambient temperature of 32°C for 2 hours. When placed in a thermally graded alleyway, animals injected with pyrogen selected gradient positions that represented significantly higher temperatures than controls injected with saline (40.4° in contrast to 36.4°C). Allowing the pups to remain at their selected positions for 5 minutes caused a significant increase in the rectal temperatures of the pyrogen-injected pups but not that of the controls. Thus, newborn rabbits will develop a fever by behavioral means after a single injection of an exogenous pyrogen.
Myosin Synthesis Increased by Electrical Stimulation of Skeletal Muscle Cell Cultures
Authors: Brevet Annie , Pinto Elaine , Peacock John , Stockdale Frank E.
Published: October 2006

When cultures of skeletal muscle cells of the chick embryo are subjected to repetitive, electrical stimulation, the contractions increase the amount of protein produced by these cells. The increase is greater for contractile proteins such as myosin heavy chain than for total cellular protein. This demonstrates that in a culture system of skeletal muscle cells that have differentiated in the absence of innervation, one can elicit the protein synthetic response associated with skeletal muscle hypertrophy in vivo.
Hyaluronidase-Induced Reductions in Myocardial Infarct Size
Authors: Maclean Derek , Fishbein Michael C. , Maroko Peter R. , Braunwald Eugene
Published: October 2006

The size of myocardial infarctions following coronary artery occlusion in the rat was determined directly by measurement of creatine phosphokinase activity in homogenized whole left ventricles and by planimetric measurement of the area of the infarctions in histologic sections of serial slices of the left ventricles. Hyaluronidase was shown to produce significant reductions in expected infarct size both 48 hours and 3 weeks after occlusion without impairing fibrosis during the healing phase. Thus, the amount of myocardial necrosis that follows a coronary artery occlusion has been shown directly to be amenable to reduction with a pharmacological intervention.
Depletion of Brain Catecholamines: Failure of Ocular Dominance Shift After Monocular Occlusion in Kittens
Authors: Kasamatsu Takuji , Pettigrew John D.
Published: October 2006

Monocularly deprived kittens were compared with littermates that had had their eyelids sutured for the same time but that had, in addition, been treated with 6-hydroxydopamine to deplete their forebrains of catecholamines. The visual cortices of all the catecholamine-depleted kittens showed high proportions of binocular neurons, in contrast to the control group, most of whose visual cortical neurons were driven exclusively by the nondeprived eye. Catecholamines may play an important role in the maintenance of cortical plasticity during the critical period.
Chronic Focal Epileptiform Discharges Induced by Injection of Iron Into Rat and Cat Cortex
Authors: Willmore L. James , Sypert George W. , Munson John B. , Hurd Russell W.
Published: October 2006

A single injection of 5 or 10 microliters of ferrous or ferric chloride into rat or cat sensorimotor cortex resulted in chronic recurrent focal paroxysmal electroencephalographic discharges as well as behavioral convulsions and electrical seizures. Recurrent focal epileptiform discharge caused by cortical injection of iron salts suggests that the development of human posttraumatic epilepsy may depend, in part, on the neurochemical alterations induced by the principal metallic ions found in whole blood.
Isolation and Properties of Chicken Erythrocyte Nuclei
Authors: Dounce Alexander L. , Lan Tien Ho
Published: October 2006

(1) A method has been described for the isolation of chicken erythrocyte nuclei using saponin to lake the cells. Nuclei prepared by this method have been compared with nuclei prepared by the method of Laskowski and with nuclei prepared by a citric acid method, particularly in regard to respiration.

(2) The total lipid content of the nuclei is about 14 per cent. and the desoxyribonucleic acid content is about 45 per cent.

(3) A yellow pigment contained in the nuclei appears to be xanthophyll.

(4) A gel formed by the nuclei at pH 8.5 in the presence of ammonia and the absence of other cations is described.
Central Nervous Regulation of Body Temperature During Sleep
Authors: Glotzbach Steven F. , Heller H. Craig
Published: October 2006

The relationship between hypothalamic temperature and metabolic heat production was measured during wakefulness, slow-wave sleep, and paradoxical sleep in unrestrained kangaroo rats (
Dipodomys
). Hypothalamic temperature was manipulated with chronically implanted, water-perfused thermodes while cortical electroencephalogram, electromyogram, metabolic rate, and body movement were continuously recorded. During slow-wave sleep, in comparison to wakefulness, there is a lowered threshold hypothalamic temperature for the metabolic heat production response and a lowered proportionality constant relating rate of metabolic heat production to hypothalamic temperature. During paradoxical sleep no increase in metabolic heat production could be elicited by lowering hypothalamic temperature, which indicates that the thermoregulatory system is inoperative. These results provide a basis for explaining the changes in various body temperatures, metabolic rate, and other thermoregulatory responses during sleep in a variety of mammals.
Regulation of Acetylcholine Synthesis: Does Cytoplasmic Acetylcholine Control High Affinity Choline Uptake?
Authors: Jenden Donald J. , Jope Richard S. , Weiler Molly H.
Published: October 2006

When brain synaptosomes are obtained from animals that have been injected intravenously with [2H4]choline 1 minute before being killed, their high affinity [3H]choline uptake is correlated inversely with their acetylcholine content and directly with the rate at which they synthesize [2H4]acetylcholine. The control of such choline uptake by the cytoplasmic acetylcholine concentration is proposed as a mechanism regulating acetylcholine synthesis in cholinergic nerve terminals.
Sex-specific Cannibalism in the Rotifer
Asplanchna sieboldi
Authors: Gilbert John J.
Published: October 2006

In one clone, large-morphotype females rarely exhibit tactile feeding responses to their ingestible, male clonemates but readily attack small-morphotype female clonemates and males of another, taxonomically distinct, clone. In the latter clone, cannibal females lack such selectivity, but their males are well protected from capture by very large, lateral body-wall outgrowths.
Cones Survive Rods in the Light-Damaged Eye of the Albino Rat
Authors: Cicerone Carol M.
Published: October 2006

Exposure to constant light causes extensive rod photoreceptor damage but spares the photopic system in albino rats. The rod branch of the dark-adaptation curve shows considerable elevation in threshold; the cone branch is hardly affected. Longer exposure and chromatic adaptation suggest that there are three cone mechanisms with peaks near wavelengths of 450, 520, and 560 nanometers.
Neural Lateralization of Species-Specific Vocalizations by Japanese Macaques (
Macaca fuscata
)
Authors: Petersen Michael R. , Beecher Michael D. , Zoloth Stephen R. , Moody David B. , Stebbins William C.
Published: October 2006

Five Japanese macaques and five other Old World monkeys were trained to discriminate among field-recorded Japanese macaque vocalizations. One task required discrimination of a communicatively relevant acoustic feature ("peak"), and a second required discrimination of an orthogonal feature of the same vocalizations ("pitch"). The Japanese animals more proficiently discriminated the peak feature when stimuli were presented to the right ear (primarily left cerebral hemisphere), as opposed to the left ear (primarily right hemisphere). In discriminating the pitch feature, the Japanese animals either showed (i) a left-ear processing advantage or (ii) no ear advantage. The comparison animals, with one exception, showed no ear advantage in processing either feature of the vocalizations. The results suggest that Japanese macaques engage left-hemisphere processors for the analysis of communicatively significant sounds that are analogous to the lateralized mechanisms used by humans listening to speech.
ISING MODEL SPIN S = 1 ON DIRECTED BARABÁSI–ALBERT NETWORKS
Authors: LIMA F. W. S.
Published: October 2006

On directed Barabási–Albert networks with two and seven neighbours selected by each added site, the Ising model with spin S = 1/2 was seen not to show a spontaneous magnetisation. Instead, the decay time for flipping of the magnetisation followed an Arrhenius law for Metropolis and Glauber algorithms, but for Wolff cluster flipping the magnetisation decayed exponentially with time. On these networks the Ising model spin S = 1 is now studied through Monte Carlo simulations. However, in this model, the order-disorder phase transition is well defined in this system. We have obtained a first-order phase transition for values of connectivity m = 2 and m = 7 of the directed Barabási–Albert network.
ESTIMATING THE FRACTAL DIMENSION OF PLANTS USING THE TWO-SURFACE METHOD: AN ANALYSIS BASED ON 3D-DIGITIZED TREE FOLIAGE
Authors: BOUDON FRÉDÉRIC , GODIN CHRISTOPHE , PRADAL CHRISTOPHE , PUECH OLIVIER , SINOQUET HERVÉ
Published: October 2006

In this paper, we present a method to estimate the fractal dimension of plant foliage in three dimensions (3D). This method is derived from the two-surface method introduced in the 90s to estimate the fractal dimension of tree species from field measurements on collections of trees. Here we adapted the method to individual plants. The multiscale topology and geometry of the plant must first be digitized in 3D. Then leafy branching systems of different sizes are constructed from the plant database, using the topological information. 3D convex envelops are then computed for each leafy branching system. The fractal dimension of the plant is finally estimated by comparing the total leaf area and the convex envelop area of these leafy modules. The method was assessed on a set of four peach trees entirely digitized at shoot scale. Results show that the peach trees have a marked self-similar foliage with fractal dimension close to 2.4.
Is active glucose transport present in bovine ciliary body epithelium?
Authors: Chan Chu Yan , Guggenheim Jeremy A. , To Chi Ho
Published: October 2006

Hyperglycemia is a major risk factor for diabetic cataract formation. Effective regulation of glucose transport by the ciliary body epithelium (CBE) is pivotal to normal glycemic control in the anterior eye, which in turn affects the glucose level of the crystalline lens. The present study aimed to characterize the glucose transport mechanisms across the bovine blood-aqueous barrier (BAB) represented by the CBE. With an Ussing-type chamber, the glucose transport kinetics were measured and characterized in the presence and absence of various glucose transporter inhibitors. The saturation characteristics of the CBE to glucose were estimated from an Eadie-Hofstee plot. The mRNA expression of glucose transporters in specific regions of the bovine CBE was assessed using RT-PCR. The trans-CBE glucose flux was found to be sensitive to the glucose transporter inhibitors cytochalasin B, phloretin, and phlorizin. The transport system had a kinetic constant of 5.3 mM and a maximum velocity of 349.5 nmol·h−1·cm−2. Gene expression for GLUT1, GLUT3, GLUT4, GLUT5, and SGLT2 was observed in both the pars plana and pars plicata regions of the bovine CBE. This study demonstrates that glucose transport across the bovine CBE is primarily passive in nature. However, the novel findings of 1) the presence of a phlorizin-sensitive glucose flux and 2) gene expression for SGLT2 mean that a potential role for active glucose transport cannot be ruled out. The elucidation of the exact function of SGLT2 in the bovine CBE may shed important light on the glucose transport and physiology of the BAB and inform future studies of glycemic control in relation to diabetic cataract formation.
Leptin antagonist reveals that the normalization of caloric intake and the thermic effect of food after high-fat feeding are leptin dependent
Authors: Zhang J. , Matheny M. K. , Tümer N. , Mitchell M. K. , Scarpace P. J.
Published: October 2006

High-fat (HF) feeding induces a transient increase in caloric intake and enhances energy expenditure. We hypothesized that leptin is necessary for homeostatic restoration of the HF-enhanced caloric intake and may mediate the increase in uncoupling protein-1 (UCP1) in brown adipose tissue (BAT). We employed a leptin antagonist to examine the role of leptin in these biological processes. Simultaneous central administration of leptin and increasing doses of the leptin antagonist revealed a dose-dependent inhibition of leptin-induced hypothalamic signal transducer and activator of transcription-3 phosphorylation, and 7 days of infusion of the leptin antagonist produced the predicted increase in food intake and weight gain. When delivered with exogenous leptin in a 7-day infusion, the leptin antagonist blocked leptin-mediated anorexic effects as well as the increase in BAT UCP1 protein and signal transducer and activator of transcription-3 phosphorylation. Rats were then fed an HF diet (60% kcal as fat) or chow and simultaneously infused with antagonist (25 μg/day into the lateral ventricle) for 7 days and compared with vehicle-infused chow-fed rats. Daily caloric intake of both HF groups peaked on day 2. HF feeding elevated caloric intake, which nearly normalized by day 7, whereas in the presence of the antagonist, caloric intake remained elevated. Moreover, the HF-mediated augmentation in UCP1 in BAT was prevented by the antagonist. These results demonstrate that leptin is essential for the homeostatic restoration of caloric intake after HF feeding and that this leptin antagonist is able to block central leptin signaling and leptin-mediated UCP1 elevation.
β-Subunit–Dependent Modulation ofhSloBK Current by Arachidonic Acid
Authors: Sun X. , Zhou D. , Zhang P. , Moczydlowski E. G. , Haddad G. G.
Published: October 2006

In this study, we examined the effect of arachidonic acid (AA) on the BK α-subunit with or without β-subunits expressed in Xenopus oocytes. In excised patches, AA potentiated the hSlo-α current and slowed inactivation only when β2/3 subunit was co-expressed. The β2-subunit–dependent modulation by AA persisted in the presence of either superoxide dismutase or inhibitors of AA metabolism such as nordihydroguaiaretic acid and eicosatetraynoic acid, suggesting that AA acts directly rather than through its metabolites. Other cis unsaturated fatty acids (docosahexaenoic and oleic acid) also enhanced hSlo-α + β2 currents and slowed inactivation, whereas saturated fatty acids (palmitic, stearic, and caprylic acid) were without effect. Pretreatment with trypsin to remove the cytosolic inactivation domain largely occluded AA action. Intracellularly applied free synthetic β2-ball peptide induced inactivation of the hSlo-α current, and AA failed to enhance this current and slow the inactivation. These results suggest that AA removes inactivation by interacting, possibly through conformational changes, with β2 to prevent the inactivation ball from reaching its receptor. Our data reveal a novel mechanism of β-subunit–dependent modulation of BK channels by AA. In freshly dissociated mouse neocortical neurons, AA eliminated a transient component of whole cell K+currents. BK channel inactivation may be a specific mechanism by which AA and other unsaturated fatty acids influence neuronal death/survival in neuropathological conditions.
Dynamics of Receptive Field Size in Primary Visual Cortex
Authors: Malone Brian J. , Kumar Vikas R. , Ringach Dario L.
Published: October 2006

Recent studies have shown that the initial responses evoked by a stimulus in neurons of primary visual cortex are dominated by low spatial frequency information in the image, whereas finer spatial scales dominate later in the response. Such phenomena could arise from the dynamics of receptive field (RF) size at early stages of cortical processing. We measured changes in RF size in simple cells recorded from the primary visual cortex of anesthetized macaques by measuring their first-order spatio-temporal kernels and fitting them with two-dimensional Gabor functions at different time slices. We found that the width and length of the RF envelope and the period of the carrier tend to decrease during the time-course of the response. The most pronounced changes are seen in the width and spatial period of the RFs, which decrease by 15% during the central 20 ms of the response. These results show a novel form of spatio-temporal inseparability in simple cells and are consistent with the notion of a coarse-to-fine processing of information in early visual cortex.
Myelin-Associated Oligodendrocytic Basic Protein: A Family of Abundant CNS Myelin Proteins in Search of a Function
Authors: Montague Paul , McCallion Andrew S. , Davies R. Wayne , Griffiths Ian R.
Published: October 2006

The myelin-associated oligodendrocytic basic protein (MOBP) family constitutes the third most abundant protein in CNS myelin. The mouse Mobp gene comprises eight exons. Mobp pre-mRNA processing gives rise to at least seven Mobp splice variants which are expressed solely in the oligodendrocyte. The predicted proteins all, with one exception, share a 68 residue amino terminus, encoded by exon 3. The carboxyl termini differ in length, giving rise to the diverse array of the protein isoforms. Like myelin basic protein, MOBP is present in the major dense line of CNS myelin suggesting a role in the compaction or stabilization of myelin. However, Mobp homozygous null mice display no overt clinical phenotype and no defect in the process of myelination. MOBP can induce experimental allergic encephalomyelitis in mice and has been proposed to have a role in the pathogenesis of multiple sclerosis. Despite 10 years of rigorous study, the normal physiological function of MOBP remains unknown.
Inhibition of PC-PLC Blocked the Survival of Mouse Neural Cells by Up-Regulating the Expression of Integrin beta4 and Rb
Authors: Lv Xin , Wang Nan , Su Le , Zhang Shangli , Miao Junying
Published: October 2006

In order to understand the survival signals of neural cells during the development of the central nervous system (CNS), we explored the role of phosphatidylcholine-specific phospholipase C (PC-PLC) in the survival of primary culture mouse neural cells (MNCs). We found that when the activity of PC-PLC in the neural cells was suppressed by its specific inhibitor, D609 (tricyclodecan-9-yl-xanthogenate), the cell survival was blocked, the viability of the cells remarkably declined. At the same time, the expressions of integrin beta4 and Rb protein were evidently elevated. We also examined the intracellular ROS (reactive oxygen species) levels after the cells were treated with D609. The result showed that the ROS level in neural cells was reduced. Our data suggested that PC-PLC had an important role in regulating neural cell survival, and PC-PLC might perform its function by upregulating the expressions of integrin beta4 and Rb protein. The changes of intracellular ROS level induced by D609 indicated that a modest level of ROS might be indispensable to neural cell survival.
Distinct but Overlapping Functions for the Closely Related p190 RhoGAPs in Neural Development
Authors: Matheson Stephen F. , Hu Kang-Quan , Brouns Madeleine R. , Sordella Raffaella , VanderHeide John D. , Settleman Jeffrey
Published: October 2006

The p190 RhoGAPs, p190A and p190B, are highly related GTPase-activating proteins for the Rho GTPases. Rho GTPases and p190A reportedly control various aspects of brain development, and we hypothesized that p190B would be likewise involved in neuronal development. We find that like p190A, p190B is prominently expressed in the developing and adult brain. Unlike p190A, p190B is not abundantly tyrosine phosphorylated. We further demonstrate, using p190B-deficient mice, that p190B is required for normal brain development. Mice lacking p190B display several major defects, including (1) deficits in the formation of major forebrain commissures, including the corpus callosum and anterior commissure, (2) dilation of the lateral ventricles, suggesting inhibition of neurogenesis and/or survival, (3) thinning of the neocortical intermediate zone, suggesting defects in neuronal differentiation and/or axonal outgrowth, and (4) impaired neuronal differentiation. These defects are similar to, but distinct from, those described in p190A-deficient mice. RNA interference-mediated knockdown of neither p190 protein results in significant inhibition of neurite outgrowth in neuroblastoma cells, despite an apparent increase in RhoA activity. We conclude that p190 RhoGAPs control pivotal aspects of neural development, including neuronal differentiation and process outgrowth, and that these effects are mediated by signaling systems that include, but are not limited to, RhoA.
Schwa Elision in Fast Speech: Segmental Deletion or Gestural Overlap?
Authors: Davidson Lisa
Published: October 2006

Pretonic schwa elision in fast speech (e.g. potato -› [pt]ato, demolish -›[dm]olish) has been studied by both phonologists and phoneticians to understandhow extralinguistic factors affect surface forms. Yet, both types of studies havemajor shortcomings. Phonological analyses attributing schwa elision to acrossthe-board segmental deletion have been based on researchers’ intuitions. Phoneticaccounts proposing that elision is best characterized as gestural overlap havebeen restricted to very few sequence types. In this study, 28 different [#CəC-]sequences are examined to define appropriate acoustic criteria for ‘elision’, toestablish whether elision is a deletion process or the endpoint of a continuum ofincreasing overlap, and to discover whether elision rates vary for individualspeakers. Results suggest that the acoustic patterns for elision are consistent withan overlap account. Individual speakers differ as to whether they increase elision
Effects of membrane and soluble EPCR on the hemostatic balance and endotoxemia in mice
Authors: Zheng Xunzhen , Li Weihong , Gu Jian-Ming , Qu Dongfeng , Ferrell Gary L. , Esmon Naomi L. , Esmon Charles T.
Published: October 2006

Recent studies have shown that endothelial protein C receptor (EPCR) polymorphisms and soluble EPCR levels are associated with thrombotic diseases. It is unknown whether membrane EPCR (mEPCR) heterozygosity and/or physiologically elevated sEPCR levels directly impact the hemostatic balance and the outcome of endotoxemia. In these studies, thrombin infusion experiments revealed that EPCR heterozygosity (Procr+/−) impaired protein C activation by approximately 30%. Infusion of factor Xa with phospholipid demonstrated that the Procr+/−genotype increased the coagulant response relative to wild-type mice. Challenge of the Procr+/− mice with lipopolysaccharide (LPS) did not significantly exaggerate their response compared with wild-type mice. We also generated mice in which one allele of full-length EPCR was replaced by sEPCR (Procrs/+). Compared with Procr+/− mice, Procrs/+ mice had 5-fold higher sEPCR and similar mEPCR levels. Procr+/− and Procrs/+ mice generated similar levels of activated protein C (APC) upon thrombin infusion. They also exhibited a similar coagulant response upon factor Xa/phospholipid infusion. Only supraphysiologic levels of sEPCR could influence protein C activation and exaggerate the coagulant response. In conclusion, mEPCR, but not physiologically elevated sEPCR, regulated protein C activation. Procr heterozygosity results in a mild increase of thrombosis tendency and little influence on the response to endotoxin.
Establishment of endolithic populations of extremophilic Cyanidiales (Rhodophyta)
Authors: Yoon Hwan Su , Ciniglia Claudia , Wu Min , Comeron Josep M , Pinto Gabriele , Pollio Antonino , Bhattacharya Debashish
Published: October 2006

Background

Cyanidiales are unicellular extremophilic red algae that inhabit acidic and high temperature sites around hot springs and have also adapted to life in endolithic and interlithic habitats. Comparative genomic analysis of Cyanidioschyzon merolae and Galdieria sulphuraria predicts that the latter may be more broadly distributed in extreme environments because its genome contains membrane transporters involved in the uptake of reduced carbon compounds that are absent from C. merolae. Analysis of an endolithic site in the Phlegrean Fields near Naples, Italy is consistent with this prediction showing this population to be comprised solely of the newly described lineage Galdieria-B and C. merolae to be limited to humid habitats. Here, we conducted an environmental PCR survey of another extreme environment in Tuscany, Italy and contrasted Cyanidiales population structure at endolithic and interlithic habitats in Naples and Tuscany.

Results

We find a second Galdieria lineage (Galdieria-A) in endolithic and interlithic habitats in Tuscany but surprisingly Cyanidium was also present at these sites. The photoautotrophic Cyanidium apparently survives below the rock surface where sufficient light is available for photosynthesis. C. merolae is absent from all endolithic and interlithic sites in Tuscany. Population genetic analyses of a partial calmodulin gene fragment suggest a recent establishment or recurrent gene flow between populations in Tuscany, whereas the highly structured Galdieria-B population in Naples likely originated from 2–3 founder events. We find evidence of several recombination events across the calmodulin gene, potentially indicating the presence of sexual reproduction in the Tuscany populations.

Conclusion

Our study provides important data regarding population structure in extreme endolithic environments and insights into how Cyanidiales may be established in and adapt to these hostile environments.
Chromatin assembly factor CAF-1 is required for cellular differentiation during plant development
Authors: Exner Vivien , Taranto Patti , Schönrock Nicole , Gruissem Wilhelm , Hennig Lars
Published: October 2006

Chromatin assembly factor CAF-1 facilitates the formation of nucleosomes on newly replicated DNA in vitro. However, the role of CAF-1 in development is poorly understood because mutants are not available in most multicellular model organisms. Biochemical evidence suggests that FASCIATA1, FASCIATA2 and MSI1 form CAF-1 in Arabidopsis thaliana. Because fasciatamutants are viable, CAF-1 is not essential for cell division in plants. Arabidopsis CAF-1 mutants have defects in shoot apical meristems; in addition, CAF-1 is required to establish seedling architecture, leaf size and trichome differentiation. CAF-1 is needed to restrict branching of trichomes on rosette leaves. Increased trichome branching in CAF-1 mutants is not strictly correlated with increased nuclear DNA content. In addition, fas2 glabra3 double mutants show an additive genetic interaction,demonstrating that CAF-1 acts genetically parallel to the GLABRA3-containing, endoreduplication-coupled trichome branching pathway. However, CAF-1 is often needed to restrict endoreduplication, because seedlings of most CAF-1 mutants have increased ploidy. Notably, in the Landsberg erecta background, loss of CAF-1 does not affect ploidy,demonstrating that loss of CAF-1 can be compensated in some Arabidopsis accessions. These results reveal that the functions of FAS1, FAS2 and MSI1 are not restricted to meristems, but are also needed to control genome replication at multiple steps of development.
The puromycin-sensitive aminopeptidase PAM-1 is required for meiotic exit and anteroposterior polarity in the one-cellCaenorhabditis elegansembryo
Authors: Lyczak Rebecca , Zweier Lynnsey , Group Thomas , Murrow Mary Ann , Snyder Christine , Kulovitz Lindsay , Beatty Alexander , Smith Kristen , Bowerman Bruce
Published: October 2006

In the nematode Caenorhabditis elegans, sperm entry into the oocyte triggers the completion of meiosis and the establishment of the embryonic anteroposterior (AP) axis. How the early embryo makes the transition from a meiotic to a mitotic zygote and coordinates cell cycle changes with axis formation remains unclear. We have discovered roles for the C. elegans puromycin-sensitive aminopeptidase PAM-1 in both cell cycle progression and AP axis formation, further implicating proteolytic regulation in these processes. pam-1 mutant embryos exhibit a delay in exit from meiosis: thus, this peptidase is required for progression to mitotic interphase. In addition, the centrosomes associated with the sperm pronucleus fail to closely associate with the posterior cortex in pam-1 mutants,and the AP axis is not specified. The meiotic exit and polarity defects are separable, as inactivation of the B-type cyclin CYB-3 in pam-1mutants rescues the meiotic exit delay but not the polarity defects. Thus PAM-1 may regulate CYB-3 during meiotic exit but presumably targets other protein(s) to regulate polarity. We also show that the pam-1 gene is expressed both maternally and paternally, providing additional evidence that sperm-donated gene products have important roles during early embryogenesis in C. elegans. The degradation of proteins through ubiquitin-mediated proteolysis has been previously shown to regulate the cell cycle and AP axis formation in the C. elegans zygote. Our analysis of PAM-1 requirements shows that a puromycin-sensitive aminopeptidase is also required for proteolytic regulation of the oocyte to embryo transition.
Sub-lethal and chronic salinity tolerances of three freshwater insects: Cloeon sp. and Centroptilum sp. (Ephemeroptera: Baetidae)and Chironomus sp. (Diptera: Chironomidae)
Authors: Hassell Kathryn L. , Kefford Ben J. , Nugegoda Dayanthi
Published: October 2006

Increased salinity in rivers and streams is a serious environmental concern, and in Australia there is growing information about the acute tolerances to salinity for freshwater macroinvertebrates, but much less information about chronic and sub-lethal tolerances. The effects of increased salinity on the growth and survival of two mayflies, Cloeon sp. and Centroptilum sp. and one midge Chironomus sp. are reported. In both mayfly species survival was variable. Complete mortality was observed in salinities with electrical conductivity of 10 mS cm–1 and higher. Salinities causing chronic mortality in mayflies were measured as 21-day LC50, and ranged from 0.90 to 2.7 mS cm–1. Growth rates were not significantly different between treatments. In Chironomus, salinity affected the mean number emerging as flying adults as well as the time to emergence. An inverted `U' shape response was observed for percentage emergence, with the greatest numbers emerging at intermediate salinities (0.65–5.0 mS cm–1). No emergence occurred at salinities of 20 mS cm–1 and higher. Time to emergence was delayed by 15–88% with increased salinity, however the size of emerged adults was the same for all treatments. Growth rates were reduced with increased salinity, showing a slow, steady reduction up to 10 mS cm–1 then a steep decline between 10 and 15 mS cm–1. The implications of altered growth rates and changes in developmental times are discussed. This study illustrates the variability in responses to increased salinity, and highlights the need to continue studying sub-lethal and chronic exposures in a range of freshwater invertebrates, in order to predict impacts of salinisation on freshwater biodiversity.
Plasticity of osmoregulatory function in the killifish intestine:drinking rates, salt and water transport, and gene expression after freshwater transfer
Authors: Scott Graham R. , Schulte Patricia M. , Wood Chris M.
Published: October 2006

We have explored intestinal function in the euryhaline killifish Fundulus heteroclitus after transfer from brackish water (10%seawater) to fresh water. Plasma Na+ and Cl–concentrations fell at 12 h post-transfer, but recovered by 7 days. Drinking rate decreased substantially at 12 h (32% of control value) and remained suppressed after 3 and 7 days in fresh water (34 and 43%). By contrast, there was a transient increase in the capacity for water absorption measured across isolated intestines in vitro (3.3- and 2.6-fold at 12 h and 3 days),which returned to baseline after 7 days. These changes in water absorption could be entirely accounted for by changes in net ion flux: there was an extremely strong correlation (R2=0.960) between water absorption and the sum of net Na+ and net Cl–fluxes (3.42±0.10 μl water μmol–1 ion). However,enhanced ion transport across the intestine in fresh water would probably not increase water uptake in vivo, because the drinking rate was far less than the capacity for water absorption across the intestine. The increased intestinal ion absorption after freshwater transfer may instead serve to facilitate ion absorption from food when it is present in the gut. Modulation of net ion flux occurred without changes in mRNA levels of many ion transporters (Na+/K+-ATPase α1a,carbonic anhydrase 2, CFTR Cl– channel,Na+/K+/2Cl– cotransporter 2, and the signalling protein 14-3-3a), and before a measured increase in Na+/K+-ATPase activity at 3 days, suggesting that there is some other mechanism responsible for increasing ion transport. Interestingly, net Cl– flux always exceeded net Na+ flux, possibly to help maintain Cl– balance and/or facilitate bicarbonate excretion. Our results suggest that intestinal NaCl absorption from food is important during the period of greatest ionic disturbance after transfer to fresh water, and provide further insight into the mechanisms of euryhalinity in killifish.
What explains the trot–gallop transition in small mammals?
Authors: Iriarte-Díaz José , Bozinovic Francisco , Vásquez Rodrigo A.
Published: October 2006

The transition from trot to gallop in quadruped mammals has been widely hypothesized to be a strategy to minimize the energetic costs of running. This view, however, has been challenged by some experimental evidence suggesting instead that this transition might be triggered by mechanical cues, and would occur when musculoskeletal stresses reach a certain critical value. All previous experiments to test those hypotheses have used relatively large species and their results, therefore, may not be applicable to small mammals. In this study we evaluated the effect of carrying loads on the locomotor energetics and gait transitions of the rodent Octodon degus running on a treadmill. Metabolic rate and cost of transport increased about 30% with a 20% increment in body mass. This increment was higher than expectations based on other mammals, where energy consumption increases in proportion to the added mass, but similar to the response of humans to loads. No abrupt change of energy consumption between gaits was observed and therefore no evidence was found to support the energetic hypothesis. The trot–gallop transition speed did not vary when subjects were experimentally loaded,suggesting that the forces applied to the musculoskeletal system do not trigger gait transition.
Escape responses in juvenile Atlantic cod Gadus morhua L.: the effects of turbidity and predator speed
Authors: Meager Justin J. , Domenici Paolo , Shingles Alex , Utne-Palm Anne Christine
Published: October 2006

We examined the effect of turbidity (0.5–14 beam attenuation m–1) and predator attack speed (150 and 296 cm s–1) on escape responses of juvenile cod Gadus morhua in the laboratory. We triggered escape responses using a predator model and measured escape timing, direction and locomotor performance. We also measured responsiveness and estimated the likelihood of fish escaping the`predator attack' (putative escape success, PES).

Turbidity affected both PES and the type of escape response used by the fish, but these effects depended on predator speed. PES for the fast predator attack declined from 73% in clear water to 21% in highly turbid water, due to decreased responsiveness and poorly timed escapes. Intermediate turbidity enhanced PES and responsiveness to the slow predator attack. Locomotor performance was reduced by turbidity, whereas predator speed had the opposite effect. Our results suggest that both predator attack speed and turbidity have important roles in determining the vulnerability of fish attacked by piscivorous predators.
Nutritional concepts in the management of the head and neck cancer patient. II. Management concepts
Authors: Sobol Steven M. , Conoyer J. Michael , Zill Roberta , Thawley Stanley E. , Ogura Joseph H.
Published: October 2006

Essential to the management of the head and neck cancer patient is carefully monitored nutritional support. Traditionally, enteral alimentation, using the nasogastric feeding tube, has been the mainstay of treatment. Tube feedings should provide ample amounts of essential nutrients, minerals, vitamins, and adequate calories and protein. Knowledge of the tube feedings available and problems associated with their administration helps to avoid the pitfalls which limit their effectiveness. The inadequacies of enteral alimentation preclude its use in selected circumstances of severe nutritional depletion. Parenteral hyperalimentation, as a primary or adjuvant mode of therapy, may be capable of rapidly reversing deficits, improving postoperative morbidity and increasing tolerance to radiation and chemotherapy. Postoperative deglutition abnormalities may prolong the nutritional problems of head and neck cancer patients as well.
Nasal and paranasal presentations of chordomas
Authors: Campbell Winston M. , Mcdonald Thomas J. , Unni Krishnan K. , Laws Edward R.
Published: October 2006

Eight patients with chordomas whose initial manifestations were caused by nasal and paranasal extension of the tumor are presented. Their ages ranged from 24 to 51 years. Disturbances of vision developed subsequently in all eight patients, and headache was present in each patient. Roentgenograms showed bony erosion of the sphenoid sinus or a naso‐pharyngeal mass. Because chordomas can be confused with chondrosarcomas histopatho‐logically, differentiation is important. Treatment consists of surgical debulking or radiotherapy (or both). Despite such treatment, six patients died from their disease. The average survival was five years. This emphasizes the well‐known poor prognosis for patients with clival chordomas.
Estrogen receptors in nasopharyngeal angiofibromas
Authors: Johns Michael E. , Macleod Robert M. , Cantrell Robert W.
Published: October 2006

Nasopharyngeal angiofibromas, which occur exclusively in pubescent males, are frequently treated with estrogens in an effort to decrease their size and vascularity. It has been presumed by some that estrogen has a direct effect on the tumor itself. Others have felt that hormone acts by affecting the pituitary‐gonadal axis.

In this study, six male patients with nasopharyngeal angiofibromas had their tumors analyzed for estrogen receptors and none were found. Despite this fact, two of these patients treated with estrogens showed clinical evidence of a decrease in tumor size and vascularity. This response occurring in the absence of estrogen receptors suggests that the action of estrogen on nasopharyngeal angiofibromas is indirect. Alternatively these tumors may be testosterone dependent, and the administration of estrogen suppresses the normal male testosterone levels, with a resultant reduction in tumor size and vascularity.

Twenty‐four patients with nasopharyngeal angiofibroma have been treated at the University of Virginia in the past 22 years. The average blood loss at operation was 1900 cc. When estrogens were administered preoperatively in 3 patients, the average blood loss was 1135 cc. Those patients who received no estrogens averaged 2000 cc blood loss. These figures do not reflect the size or extent of the disease, both of which greatly influence blood loss.
Midline destructive granuloma: Factor fiction
Authors: Harrison D. F. N.
Published: October 2006

Although differentiation of Wegener's granulomatosis from other destructive midline lesions is now clearly recognized by clinicians and pathologists, confusion persists regarding the management of what has erroneously been called “lethal midline granuloma.” The experiences of 36 patients with destructive midline granuloma supports the view that probably all are manifestations of malignant lymphoma and should be treated as such. Although radical dosage radiotherapy will control most local lesions, dissemination of lymphoma may still occur despite absence of systemic disease at initial diagnostic work‐up. Subsequent control with cytotoxic drugs is frequently unsuccessful, and it is suggested that chemotherapy should be given routinely to every patient with primary nasal lymphoma and possibly to those with polymorphic reticulosis or necrosis with atypical cellular exudate (NACE).
Petrous apex and subarcuate fossa maturation
Authors: Hilding David A.
Published: October 2006

During the first year of life, the bone of the petrous apex grows rapidly. At birth, only 5 mm of bone separates the cochlea from Dorello's canal as compared to 2 cm in the adult. More than half this growth occurs during the first year of life. The subarcuate fossa is a cavity within the superior semicircular canal which reaches from the posterior fossa to the future mastoid in fetuses and nearly to the mastoid antrum in newborns. During the second year of left it is nearly obliterated to form a shallow depression or slit on the posterior aspect of the temporal bone and the variable petromas‐toid canal which contains the subarcuate artery and vein. Clinical petrositis of infants less that 1 year of age is rare, and provides a challenge for surgery. A case is reported and discussed.
The Plan Hidrolgico Nacional: a missed opportunity or a wily exercise in pragmatic governance?
Authors: McFall Anne
Published: October 2006

Although Spain's much-debated and long-awaited national water plan, the Plan Hidrolgico Nacional (PHN), was finally approved by the Cortes on 20 June 2001, it is clear that the Partido Popular's (PP) battle is far from won: the plan's critics continue to work unremittingly to try to
prevent some of the controversial aspects of the PHN from being implemented and their unremitting efforts may succeed in derailing the Spanish government's flagship scheme.
New science, capacity development and institutional change: the case of the Andhra Pradesh-Netherlands Biotechnology Programme (APNLBP)
Authors: Clark Norman , Yoganand B , Hall Andy
Published: October 2006

North-South cooperation in the field of science and technology has been hampered by scientific and bureaucratic conventions that fail to see the systemic nature of knowledge creation and innovation. This paper discusses a Dutch development assistance programme on biotechnology that
has made a specific effort to overturn these conventions. Using the example of the Andhra Pradesh-Netherlands Biotechnology Programme, the paper describes how this novel type of capacity development intervention takes a long-term perspective on institutional learning and change. The philosophy
underpinning this is the integrated bottom up approach, which emphasises direct links with user communities. It thus engages directly with the question of how a more socially embedded process of innovation may be developed that can permit biotechnology to be exploited for sustainable development.
Bis(formamidine–urea) Complexes of NiII and CuII:Synthesis, Characterization, and Reactivity
Authors: Díaz David D. , Sen Gupta Sayam , Kuzelka Jane , Cymborowski Marcin , Sabat Michal , Finn M. G.
Published: October 2006

A novel chelating chiral bis(formamidine–urea) ligand was synthesized and used to prepare the corresponding NiII and CuII complexes. Spectroscopic and X‐ray crystallographic analysis of the former revealed that the urea moiety of the acyclic tetradentate ligand is deprotonated and binds to the square‐planar Ni2+ ion through amide nitrogen atoms. This complex showed quasi‐reversible redox behavior in cyclic voltammetry, with E1/2 = 640 mV vs. Cp2Fe+/Cp2Fe corresponding to the NiIII/NiII couple. The Cu complex was shown by EPR spectroscopy to also adopt a square‐planar geometry [g∥ = 2.25 (A∥ = 184 G), g⟂ = 2.06 at 6 K], and reduction was found to be irreversible, perhaps due to the rigid nature of the tetradentate ligand. The nickel complex was found to be a modestly active catalyst for epoxidation of electron‐richalkenes under Mukaiyama’s conditions, likely involving a radical mechanism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)