bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal structures of recombinant and native soybean β‐conglycinin β homotrimers
Authors: Maruyama Nobuyuki , Adachi Motoyasu , Takahashi Koji , Yagasaki Kazuhiro , Kohno Mitsutaka , Takenaka Yasuyuki , Okuda Eiko , Nakagawa Shuko , Mikami Bunzo , Utsumi Shigeru
Published: March 2003

The crystal structures of recombinant and native β homotrimers of soybean β‐conglycinin were determined by X‐ray crystallography at 2.7 and 2.8 Å resolutions, respectively. The crystals of the recombinant and native β homotrimers belong to space group P21 with cell parameters a = 80.51 Å, b = 63.48 Å, c = 131.43 Å, and β = 90.01° and with cell parameters a = 82.78 Å, b = 69.47 Å, c = 125.33 Å and β= 97.22°, respectively. The β monomers consist of amino‐terminal and carboxyl‐terminal modules that are very similar to each other and are related by a pseudo‐dyad axis. Each module of the β monomer is subdivided into a core and a loop domain. These structural features of both β homotrimers are consistent with those of canavalin and phaseolin, which are similar vicilin class proteins. The superposition of the models of the native and recombinant β monomers shows a root mean square deviation of 0.43–0.51 Å for 343 common Cα atoms within 2.0 Å. This result indicates that the N‐linked glycans do not influence the final structure of the β homotrimer. Comparison of the models of β‐conglycinin, phaseolin and canavalin indicates that β‐conglycinin resembles canavalin rather than phaseolin, and that canavalin and phaseolin differ the most among them. The evolutional relationships are discussed.
The NADH‐dependent reductase of a putative multicomponent tetrahydrofuran mono‐oxygenase contains a covalently bound FAD
Authors: Thiemer Barbara , Andreesen Jan R. , Schräder Thomas
Published: March 2003

NADH–cytochrome c oxidoreductase activity specifically expressed during growth on tetrahydrofuran was detected in cell extracts of Pseudonocardia sp. strain K1. The enzyme catalyzing this reaction was purified to apparent homogeneity by a three‐step purification procedure. It was characterized as a monomer of apparent molecular mass 40 kDa. Spectroscopic studies indicated that it contains an iron–sulfur cluster and a flavin cofactor. An amount of 1 mol of flavin and 1 mol of iron was determined per mol of homogeneous protein. The N‐terminal amino‐acid sequence exhibited great similarity to the reductase component of various oxygenases. Cloning and sequencing of the corresponding gene designated as thmD revealed an ORF encoding a protein of 360 amino acids. An overall similarity of up to 38% was obtained to the NAD(P)H–acceptor reductase of several binuclear iron‐containing mono‐oxygenases. Conserved sequence motifs were identified that were similar to the chloroplast‐type ferredoxin 2Fe−2S centre and to nucleotide‐binding domains. Studies on the flavin cofactor showed that it could not be removed from the protein by denaturation, indicating a covalent attachment. Spectroscopic studies revealed that the flavin is at the FAD level and covalently bound to the protein via the flavin 8α‐methyl group. Thus, the isolated reductase component is the first enzyme of this type for which a covalent attachment of the flavin has been observed.
The conserved Asn49 of maize glutathione S‐transferase I modulates substrate binding, catalysis and intersubunit communication
Authors: Labrou Nikolaos E. , Mello Luciane V. , Clonis Yannis D.
Published: March 2003

The functional and structural role of the conserved Asn49 of theta class maize glutathione S‐transferase was investigated by site‐directed mutagenesis. Asn49 is located in the type I β turn formed by residues 49–52, and is involved in extensive hydrogen‐bonding interactions between α helix 2 and the rest of the N‐terminal domain. The substitution of Asn49 with Ala induces positive cooperativity for 1‐chloro‐2,4‐dinitrobenzene (CDNB) binding as reflected by a Hill coefficient of 1.9 (

= 0.43 mm). The positive cooperativity is also confirmed by following the isothermic binding of 1‐hydroxyl‐2,4‐dinitrobenzene (HDNB) by UV‐difference spectroscopy. In addition, the mutated enzyme exhibits: (a) an increase in the
value of about 6.5‐fold, and decrease in kcat value of about fourfold; (b) viscosity‐independent kinetic parameters; (c) lower thermostability, and (d) increased susceptibility to proteolytic attack by trypsin, when compared to the wild‐type enzyme. It is concluded that Asn49 affects the rate‐limiting step of the catalytic reaction, and contributes significantly to the structural and binding characteristics of both the glutathione binding site (G‐site) and the electrophile substrate binding site (H‐site) by affecting the structural integrity of a type I β turn (comprising residues 49–52) and probably the flexibility of the highly mobile short 310 helical segment of α helix 2 (residues 35–46). These structural perturbations are probably transmitted, via Phe51 and Phe65, to α helix H3′′ of the adjacent subunit which contains key residues that interact with the electrophile substrate and contribute to the monomer–monomer contact region. This may accounts for the positive cooperativity observed.
Further evidence for the involvement of insulin receptor substrates in epidermal growth factor‐induced activation of phosphatidylinositol 3‐kinase
Authors: Fujioka Toshiyuki , Kim Jae‐Hoon , Adachi Hideki , Saito Kazuki , Tsujimoto Masafumi , Yokoyama Shigeyuki , Ui Michio
Published: March 2003

In accordance with our recent results obtained with cultured rat hepatocytes [Fujioka, T. & Ui, M. (2001) Eur. J. Biochem.268, 25–34], epidermal growth factor (EGF) gave rise to transient tyrosine phosphorylation of insulin receptor substrates (IRS‐1 and IRS‐2), thereby activating the bound phosphatidylinositol 3‐kinase in human epidermoid carcinoma A431 cells normally abundant in EGF receptors (EGFR) and Chinese hamster ovary (CHO) cells transfected with full‐length EGFR. These actions of EGF, although much smaller in magnitude than those of insulin or IGF‐I in the same cells, were accompanied by tyrosine phosphorylation of EGFR rather than insulin or IGF‐I receptors, never observed in wild‐type CHO cells expressing no EGFR, and totally inhibited by an inhibitor of EGFR kinase, AG1478, that was without effect on insulin or IGF‐I actions. Recombinant IRS‐1 was phosphorylated on tyrosines upon incubation with purified EGFR from A431 cells and 32P‐labeled ATP. When CHO cells were transfected with C‐terminal truncated EGFR lacking three NPXY motifs responsible for direct binding to phosphotyrosine‐binding domains of IRSs, no effect of EGF could be observed. We suggest that tyrosine phosphorylation of IRS‐1 or IRS‐2 could mediate EGFR‐induced activation of phosphatidylinositol 3‐kinase in mammalian cells.
The peroxidase activity of cytochrome c‐550 from Paracoccus versutus
Authors: Diederix Rutger E. M. , Ubbink Marcellus , Canters Gerard W.
Published: March 2003

Next to their natural electron transport capacities, c‐type cytochromes possess low peroxidase and cytochrome P‐450 activities in the presence of hydrogen peroxide. These catalytic properties, in combination with their structural robustness and covalently bound cofactor make cytochromes c potentially useful peroxidase mimics. This study reports on the peroxidase activity of cytochrome c‐550 from Paracoccus versutus and the loss of this activity in presence of H2O2. The rate‐determining step in the peroxidase reaction of cytochrome c‐550 is the formation of a reactive intermediate, following binding of peroxide to the haem iron. The reaction rate is very low compared to horseradish peroxidase (approximately one millionth), because of the poor accessibility of the haem iron for H2O2, and the lack of a base catalyst such as the distal His of the peroxidases. This is corroborated by the linear dependence of the reaction rate on the peroxide concentration up to at least 1 m H2O2. Steady‐state conversion of a reducing substrate, guaiacol, is preceded by an activation phase, which is ascribed to the build‐up of amino‐acid radicals on the protein. The inactivation kinetics in the absence of reducing substrate are mono‐exponential and shown to be concurrent with haem degradation up to 25 mm H2O2 (pH 8.0). At still higher peroxide concentrations, inactivation kinetics are biphasic, as a result of a remarkable protective effect of H2O2, involving the formation of superoxide and ferrocytochrome c‐550.
Interaction of hemoglobin with enterobacterial lipopolysaccharide and lipid A
Authors: Jürgens Gudrun , Müller Mareike , Koch Michel H. J. , Brandenburg Klaus
Published: March 2003

The interaction of hemoglobin (Hb) with endotoxins [i.e. with enterobacterial deep rough mutant lipopolysaccharide (LPS) Re and the ‘endotoxic principle’ of LPS, lipid A] was investigated using a variety of physical techniques and with two biological assays, tumor necrosis factor (TNF)‐α induction in human mononuclear cells and the Limulus amebocyte lysate (LAL) assay. Fourier‐transform IR‐spectroscopic experiments indicate nonelectrostatic binding to the hydrophobic moiety with a slight rigidification of the lipid A acyl chains, and an increase in the inclination of the lipid A backbone with respect to the membrane surface from 35° to more than 40° due to Hb binding, but no change of the predominantly α‐helical secondary structures of Hb due to LPS binding. From isothermal titration calorimetry, the molar [Hb] : [endotoxin] binding ratio lies between 1 : 3 and 1 : 5 molar. Synchrotron radiation X‐ray diffraction measurements indicate a reorientation of the lipid A aggregates from one cubic structure to another, the final structure belonging to space group Q224. The LPS‐induced TNF‐α production of mononuclear cells is enhanced by Hb, whereas in the LAL assay an LPS concentration‐dependent increase or decrease was observed. Although a detailed mechanism of action cannot be given, the enhancement of LPS bioactivity can be understood in the light of the previously presented conformational concept; Hb induces an increase in the conical shape of the lipid A moiety of LPS, higher cross‐section of the hydrophobic than the hydrophilic part, and of the inclination angle of the diglucosamine backbone with respect to the direction of the acyl chains.
Characterization of novel structures of mannosylinositolphosphorylceramides from the yeast forms of Sporothrix schenckii
Authors: Penha Carla V. Loureiro y , Todeschini Adriane R. , Lopes‐Bezerra Leila M. , Wait Robin , Jones Christopher , Mattos Katherine A. , Heise Norton , Mendonça‐Previato Lucia , Previato Jose O.
Published: March 2003

Novel structures of glycoinositolphosphorylceramide (GIPC) from the infective yeast form of Sporothrix schenckii were determined by methylation analysis, mass spectrometry and NMR spectroscopy. The lipid portion was characterized as a ceramide composed of C‐18 phytosphingosine N‐acylated by either 2‐hydroxylignoceric acid (80%), lignoceric (15%) or 2,3‐dihydroxylignoceric acids (5%). The ceramide was linked through a phosphodiester to myo‐inositol (Ins) which is substituted on position O‐6 by an oligomannose chain. GIPC‐derived Ins oligomannosides were liberated by ammonolysis and characterized as:

These structures comprise a novel family of fungal GIPC, as they contain the Manpα1→6Ins substructure, which has not previously been characterized unambigously, and may be acylated with a 2,3 dihydroxylignoceric fatty acid, a feature hitherto undescribed in fungal lipids.
Domain structure of riboflavin synthase
Authors: Eberhardt Sabine , Zingler Nora , Kemter Kristina , Richter Gerald , Cushman Mark , Bacher Adelbert
Published: March 2003

Riboflavin synthase of Escherichia coli is a homotrimer of 23.4 kDa subunits catalyzing the formation of the carbocyclic ring of the vitamin, riboflavin, by dismutation of 6,7‐dimethyl‐8‐ribityllumazine. Intramolecular sequence similarity suggested that each subunit folds into two topologically similar domains. In order to test this hypothesis, sequence segments comprising amino‐acid residues 1–97 or 101–213 were expressed in recombinant E. coli strains. The recombinant N‐terminal domain forms a homodimer that can bind riboflavin, 6,7‐dimethyl‐8‐ribityllumazine and trifluoromethyl‐substituted 8‐ribityllumazine derivatives as shown by absorbance, circular dichroism, and NMR spectroscopy. Most notably, the recombinant domain dimer displays the same diastereoselectivity for ligands as the full length protein. The minimum N‐terminal peptide segment required for ligand binding comprises amino‐acid residues 1–87. The recombinant C‐terminal domain comprising amino‐acid residues 101–213 is relatively unstable and was shown not to bind riboflavin but to differentiate between certain diastereomeric trifluoromethyl‐8‐ribityllumazine derivatives. The data show that a single domain comprises the intact binding site for one substrate molecule. The enzyme‐catalyzed dismutation requires two substrate molecules to be bound in close proximity, and each active site of the enzyme appears to be located at the interface of an N‐terminal and C‐terminal domain.
Identification and cloning of an 85‐kDa protein homologous to RING3 that is upregulated in proliferating endothelial cells
Authors: BelAiba Rachida‐Siham , Baril Patrick , Chebloune Yahia , Tabone Eric , Boukerche Habib
Published: March 2003

A central event in angiogenesis is proliferation of blood vessels, which plays a major role in the progression of a number of inflammatory and neoplastic diseases. It is responsible for the switch of endothelial cells from an antiangiogenic to an angiogenic phenotype. To identify novel activated/proliferating‐related proteins in human endothelial cells, a subtractive immunization approach was used to elicit a host antibody response against human dermal microvascular endothelial cells (HDMECs) stimulated with a potent angiogenic cytokine such as VPF/VEGF165. In this study, a new mAb, LY9, which is highly specific to VPF/VEGF165‐activated HDMECs, was isolated. Stimulation of HDMECs by VPF/VEGF165 or basic fibroblast growth factor (bFGF) resulted in a dose‐dependent and time‐dependent increase in the binding of LY9. On Western‐blot analysis, LY9 identified an 85‐kDa protein (p85) in the lysates of several endothelial cells derived from microvascular or large vessel sources, the expression of which is dramatically increased by VPF/VEGF165. The mAb also identified p85 in primary cell cultures of human foreskin keratinocytes but failed to recognize human fibroblasts (MRC5) and a number of different human tumor cell lines, including MG63 osteosarcoma and MCF7 breast carcinoma cells. Immunological screening of a human keratinocyte λgt11 cDNA expression library with LY9 identified a partial cDNA clone of 750 bp. DNA sequencing of this clone and predicted amino acids showed more than 93% homology to RING3 kinase, a member of a newly described family of bromodomain‐containing proteins that transactivates in the nucleus the promoters of a number of the E2F family of transcription factors. This molecule may represent a new signaling target activated by VPF/VEGF165 and bFGF that allows endothelial cells to enter the proliferative phase of the angiogenic process.
The amino‐acid sequence of the glucose/mannose‐specific lectin isolated from Parkia platycephala seeds reveals three tandemly arranged jacalin‐related domains
Authors: Mann Karlheinz , Farias Creuza M. S. A. , Del Sol Francisca Gallego , Santos Claudia F. , Grangeiro Thalles B. , Nagano Celso S. , Cavada Benildo S. , Calvete Juan J.
Published: March 2003

A mannose/glucose‐specific lectin was isolated from seeds of Parkia platycephala, the most primitive subfamily of Leguminosae plants. The molecular mass of the purified lectin determined by mass spectrometry was 47 946 ± 6 Da (by electrospray ionization) and 47 951 ± 9 Da (by matrix‐assisted laser‐desoption ionization). The apparent molecular mass of the lectin in solutions of pH in the range 4.5–8.5 determined by analytical ultracentrifugation equilibrium sedimentation was 94 ± 3 kDa, showing that the protein behaved as a non‐pH‐dependent dimer. The amino‐acid sequence of the Parkia lectin was determined by Edman degradation of overlapping peptides. This is the first report of the primary structure of a Mimosoideae lectin. The protein contained a blocked N‐terminus and a single, nonglycosylated polypeptide chain composed of three tandemly arranged homologous domains. Each of these domains shares sequence similarity with jacalin‐related lectin monomers from Asteraceae, Convolvulaceae, Moraceae, Musaceae, Gramineae, and Fagaceae plant families. Based on this homology, we predict that each Parkia lectin repeat may display a β prism fold similar to that observed in the crystal structure of the lectin from Helianthus tuberosus. The P. platycephala lectin also shows sequence similarity with stress‐ and pathogen‐upregulated defence genes of a number of different plants, suggesting a common ancestry for jacalin‐related lectins and inducible defence proteins.
Rapid, ATP‐dependent degradation of a truncated D1 protein in the chloroplast
Authors: Preiss Susanne , Schrader Silke , Johanningmeier Udo
Published: March 2003

The D1 protein constitutes one of the reaction center subunits of photosystem II and turns over rapidly due to photooxidative damage. Here, we studied the degradation of a truncated D1 protein. A plasmid with a precise deletion in the reading frame of the psbA gene encoding D1 was introduced into the chloroplast of Chlamydomonas reinhardtii. A homoplasmic mutant containing the desired gene was able to synthesize the truncated form of the polypeptide, but could not accumulate significant levels of it. As a consequence, other central photosystem II subunits did not assemble within the thylakoid membrane. In vivo pulse–chase experiments showed that the abnormal D1 protein is rapidly degraded in the light. Degradation was delayed in the light in the presence of an uncoupler, or when cells were incubated in the dark. Pulse–chase experiments performed in vitro indicate that an ATP and metal‐dependent protease is responsible for the breakdown process. The paper describes the first in vivo and in vitro functional test for ATP‐dependent degradation of a defect polypeptide in chloroplasts. The possible involvement of proteases similar to those removing abnormal proteins in prokaryotic organisms is discussed on the basis of proteases recently identified in chloroplasts.
Structural analysis of the lipopolysaccharide core of a rough, cystic fibrosis isolate of Pseudomonas aeruginosa
Authors: Knirel Yuriy A. , Bystrova Ol'ga V. , Shashkov Alexander S. , Lindner Buko , Kocharova Nina A. , Senchenkova Sof'ya N. , Moll Hermann , Zähringer Ulrich , Hatano Kazue , Pier Gerald B.
Published: March 2003

Lipopolysaccharide (LPS) expressed by isolates of Pseudomonas aeruginosa from cystic fibrosis patients lacks the O‐polysaccharide chain but the degree to which the rest of the molecule changes has not been determined. We analyzed, for the first time, the core structure of an LPS from a rough, cystic fibrosis isolate of P. aeruginosa. The products of mild acid hydrolysis and strong alkaline degradation of the LPS were studied by ESI MS, MALDI MS, and NMR spectroscopy. The following structure was determined for the highest‐phosphorylated core‐lipid A backbone oligosaccharide isolated after alkaline deacylation of the LPS:

 where Kdo and Hep are 3‐deoxy‐d‐manno‐octulosonic acid and l‐glycero‐d‐manno‐heptose, respectively; all sugars are in the pyranose form and have the d configuration unless stated otherwise. The outer core region occurs as two isomeric glycoforms differing in the position of rhamnose (Rha). The inner core region carries four phosphorylation sites at two Hep residues, HepI being predominantly bisphosphorylated and HepII monophosphorylated. In the intact LPS, both Hep residues carry monophosphate and diphosphate groups in nonstoichiometric quantities, GalN is N‐acylated by an l‐alanyl group, HepII is 7‐O‐carbamoylated, and the outer core region is nonstoichiometrically O‐acetylated at four sites. Therefore, the switch to the LPS‐rough phenotype in cystic fibrosis isolates of P. aeruginosa is not accompanied by losses of core monosaccharide, phosphate or acyl components. The exact positions of the O‐acetyl groups and the role of the previously undescribed O‐acetylation in the LPS core of P. aeruginosa remain to be determined.
The action of starch synthase II on 6′′′‐α‐maltotriosyl‐maltohexaose comprising the branch point of amylopectin
Authors: Damager Iben , Denyer Kay , Motawia Mohammed Saddik , Møller Birger Lindberg , Blennow Andreas
Published: March 2003

The principle of using a chemically synthesized, well‐defined branched oligosaccharide to provide a more detailed knowledge of the substrate specificity of starch synthase II (SSII) is demonstrated. The branched nonasaccharide, 6′′′‐α‐maltotriosyl‐maltohexaose, was investigated as a primer for particulate SSII using starch granules prepared from the low‐amylose pea mutant lam as the enzyme source. The starch granule preparation from the lam pea mutant contains no starch synthases other than SSII and is devoid of α‐amylase, β‐amylase and phosphorylase activity. SSII was demonstrated to catalyse a specific nonprocessive elongation of the nonreducing end of the shortest unit chain of 6′′′‐α‐maltotriosyl‐maltohexaose, i.e. the maltotriose chain. Maltotriose and maltohexaose, representing the two linear building units of the branched nonasaccharide, were also tested as primers for SSII. Maltotriose was elongated more efficiently than 6′′′‐α‐maltotriosyl‐maltohexaose and maltohexaose was used less efficiently. Compared to the surface exposed α‐glucan chains of the granule bound amylopectin molecules, all three soluble oligosaccharides tested were poor primers for SSII. This indicates that in vivo, the soluble oligosaccharides supposedly released as result of amylopectin trimming reactions are not re‐introduced into starch biosynthetic reactions via the action of the granule bound fraction of SSII.
The human β‐globin locus control region
Authors: Levings Padraic P. , Bungert Jörg
Published: March 2003

The human β‐globin gene locus is the subject of intense study, and over the past two decades a wealth of information has accumulated on how tissue‐specific and stage‐specific expression of its genes is achieved. The data are extensive and it would be difficult, if not impossible, to formulate a comprehensive model integrating every aspect of what is currently known. In this review, we introduce the fundamental characteristics of globin locus regulation as well as questions on which much of the current research is predicated. We then outline a hypothesis that encompasses more recent results, focusing on the modification of higher‐order chromatin structure and recruitment of transcription complexes to the globin locus. The essence of this hypothesis is that the locus control region (LCR) is a genetic entity highly accessible to and capable of recruiting, with great efficiency, chromatin‐modifying, coactivator, and transcription complexes. These complexes are used to establish accessible chromatin domains, allowing basal factors to be loaded on to specific globin gene promoters in a developmental stage‐specific manner. We conceptually divide this process into four steps: (a) generation of a highly accessible LCR holocomplex; (b)␣recruitment of transcription and chromatin‐modifying complexes to the LCR; (c) establishment of chromatin domains permissive for transcription; (d) transfer of transcription complexes to globin gene promoters.
Female Choice in the Synchronously Waving Fiddler CrabUca annulipes
Authors: Backwell P. R. Y. , Jennions . , Christy J. H. , Passmore N. I.
Published: March 2003

In the fiddler crab,Uca annulipes, males attract receptive females into their burrows by waving their greatly enlarged major claw. We have previously shown that males clustered around a female wave in close synchrony. Females may have a preference for leading signals and synchronised waving may arise as an epiphenomenon of competition between males to signal first. Indeed, the males in clusters that females approach and visit in their burrows are more likely to produce leading waves than are their neighbours. Here we document two other differences in the waving behaviour of visited males and their neighbours. First, visited males complete the downward component of the wave more rapidly than their neighbours. Second, the interval between the end of one wave and the start of the next is shorter for visited males. How can waving be synchronous if visited males wave faster than their neighbours? While only 9% (40/431) of waves by neighbours did not overlap those of the visited male, 22% (110/501) of visited male waves did not overlap the wave of a focal neighbour (111 visited male‐neighbour dyads). Hence, while overlapping waves are nearly synchronous, visited males produce additional, ‘nonoverlapping’ waves that result in a higher wave rate than that of their neighbours.
A Combination of Chemosensory and Mechanosensory Stimuli Triggers the Male Mating Response in the Giant Rotifer Asplanchna sieboldi
Authors: Joanidopoulos Konstantin D. , Marwan Wolfgang
Published: March 2003

The rotifer Asplanchna sieboldi performs several well‐defined behavioural responses to external stimuli. Contact of male and female occasionally elicits a mating response in the male. The mating response is composed of a series of distinct behavioural elements. After the initial contact, the male stretches out its body wall outgrowths, arcs into a characteristic mating posture and glides along the surface of the female until the penis becomes attached to the female’s body wall, through which the spermatozoa are injected. Under experimental conditions, the mating response could be evoked by stimulation with agar spheres that were impregnated with extracts prepared from females, while agar spheres prepared from buffer only did not cause any mating response. If the active substance was added directly to the suspending medium in the observation chamber, mating could be triggered just by mechanical stimulation. It is concluded that the mating response is triggered by a combination of chemical and mechanical stimuli. During the time course of the experiment there was no adaptation to the chemical stimulus. The receptor cells involved in the perception of the two stimuli remain to be identified. The mating response suppressed other behavioural responses that are usually triggered by tactile stimulation of the apical mechanosensors, suggesting that signal processing by the nervous system occurs.
The Market Effect in the Wood Mouse,Apodemus sylvaticus:Selling Information on Reproductive Status
Authors: Stopka Pavel , Macdonald David W.
Published: March 2003

Grooming in the wood mouse is a means by which males obtain information about the reproductive state of females, as grooming creates a situation which allows the male to smell the groomed female’s anogenital area to ascertain her phase of oestrus. Although grooming is reciprocal in this species, it is asymmetrical in that males groom females more often than vice versa. This grooming asymmetry was studied using Markov chain analysis for grooming sequences in two captive wood mouse colonies, and transition rates were used to represent motivation in both sexes. Grooming sessions were often initiated by a male’s attempt to sniff an immobile female’s anogenital region, while the female would immediately react by avoiding or biting the male. In order to entice the female to remain, the male would begin grooming the female’s head and shoulder area, surreptitiously and consistently grooming downwards towards the female’s anogenital region, until she would again terminate such contact either by avoiding or biting the male. While, therefore, the male’s tendency to sniff the female’s anogenital region was stronger than his tendency to groom her, the female’s tendency to terminate the male’s naso‐anal contact was much stronger than her tendency to terminate his grooming bouts. If the male did not initiate grooming after the female terminated naso‐anal contact, she avoided further contacts and escaped. In mice, as in most mating systems, the demand for matings by males is far larger than the number of matings females offer. The mating market, therefore, is highly skewed, which gives females the opportunity to demand ‘commodities’ in return for allowing males to mate. This system allows females to ‘bargain’ with males to obtain grooming in return for anogenital contact. Females assess the length of time they receive grooming and will only allow males to attain anogenital contact after a certain threshold value has been passed. If anogenital contact provides the male with information about the female’s reproductive state and/or with sexual stimulation, then this process represents the first quantified example in short‐lived mammals of females ‘selling sex’ in terms of the market effect. This paper therefore provides a new view of the regulation of grooming: grooming is not simply reciprocal with both participants concerned that the other does not ‘cheat’ (e.g. tit‐for‐tat (TFT)‐like strategy), rather grooming is a commodity which can be bartered against female reproductive information or matings.
Call Structure Variability and Field Survival among Bushcrickets Exposed to Phonotactic Parasitoids
Authors: Allen Geoff R.
Published: March 2003

Calling adult males of the univoltine bushcricket Sciarasaga quadrata are subject to significant mortality from the phonotactic parasitoid fly Homotrixa alleni. These flies kill their host within 14d and act as a constant ‘filter’ on the survival of male bushcrickets. In this study, I investigate both short‐term and lifetime variability in male call structure and compare the call properties of collections of males made over a 3‐mo calling season to establish whether there are any significant differences in the call properties of males surviving the length of the calling season. Call frequency, chirp length, interchirp length, chirp rate, file teeth used to make a chirp and duty cycle all showed good differentiation among males and significant repeatability: (1) within a calling bout (0.57–0.88), (2) between successive nights (0.27–0.83), and (3) over a male's lifetime (0.15–0.43). Frequency and to a lesser extent chirp length showed low variability within and among males whereas interchirp length was the most flexible and dynamic call property. As males aged, chirp length, which is produced by one wing closure, and its correlate, teeth per chirp, significantly increased and chirp rate significantly decreased. Over the calling season chirp length and teeth per chirp showed strong directional shifts. Shorter chirp males were lost from the calling population, indicating that flies may use chirp length as a cue in host location. The implications of this result are discussed in relation to the reproductive fitness of male S. quadrata and within the context of host location and sensory bias in phontotactic parasitoids.
Patterns of Vocal Interactions in a Bullfrog (Rana catesbeiana) Chorus: Preferential Responding to Far Neighbors
Authors: Boatright‐Horowitz Su L. , Horowitz Seth S. , Simmons Andrea M.
Published: March 2003

In chorusing species, males seem to be spaced non‐randomly, and their vocal interactions may be governed by particular behavioral rules. We monitored patterns of vocal interactions in a natural bullfrog (Rana catesbeiana) chorus to determine the probability with which calls of individual frogs would follow each other's in dyadic sequences. Expected probabilities of responses in a dyad were calculated based upon the joint probabilities of calling (relative calling rates) of the individual frogs; observed probabilities of response reflected the actual number of following responses in each dyad. Results of statistical tests comparing observed and expected probabilities of responding revealed that, when dyads were closely spaced, observed probabilities of a following response were significantly less than the expected probabilities. Conversely, when dyads were composed of more distant males, observed probabilities of responding were significantly greater than expected. Observed probabilities of response were correlated with inter‐male distances; males called more frequently than expected following calls of far neighbors, and less frequently than expected following calls of near neighbors. These data suggest that males attend to both nearby and distant callers, and adjust the onset of their own vocalizations appropriately. Males may be actively inhibited by calls of their near neighbors, and their calling may be actively elicited by the calls of their far neighbors.
Adult–Adult Play in Primates: Comparative Analyses of its Origin, Distribution and Evolution
Authors: Pellis Sergio M. , Iwaniuk Andrew N.
Published: March 2003

Comparative analyses were conducted on a data set derived from the literature so as to test several hypotheses which were developed to explain the distribution of adult–adult play fighting within the order primates. Ratings for play occurring in sexual and non‐sexual contexts were developed. Three hypotheses were evaluated: (i) that play occurring in non‐sexual social contexts is a byproduct of its use in sex; (ii) that the occurrence of play is related to its use for social assessment and manipulation, and so is more likely to be present in species with reduced familiarity between individuals; and (iii) that phylogenetic affiliation influences the likelihood that species within clades engage in play. We used independent contrasts to test the first two hypotheses, and both were significant, with the presence of play in sexual contexts accounting for 14–16% of the variance of play in non‐sexual contexts, and reduced social familiarity accounting for 30–40% of the variance in the occurrence of play in non‐sexual contexts. To test the third hypothesis, we mapped the occurrence of both types of play onto known phylogenies. The overlap was not congruent, indicating that phylogenetic relationships did not account for the distribution of play. Given that play in both sexual and non‐sexual contexts was more likely to occur in species with a social organization involving reduced frequency of contact between the sexes and other social group members, we suggest that the likely adaptive value of play fighting is as a tool for social assessment and manipulation. The possible factors that mitigate the use of play fighting for these purposes, such as the availability of other forms of communication that could serve similar functions, are discussed.
Singing in the Face of Danger: the Anomalous Type II Vocalization of the Splendid Fairy‐Wren
Authors: Zelano Bethanne , Tarvin Keith A. , Pruett‐Jones Stephen
Published: March 2003

Males of certain species of fairy‐wrens (Aves: Maluridae) emit a unique vocalization, the Type II vocalization, in response to the calls of potential predators. We conducted field observations and playback experiments to identify the contexts in which the Type II vocalization is emitted by splendid fairy‐wren (Malurus splendens) males, and to examine social and genetic factors that influence its occurrence. In field observations and controlled playback experiments, Type II vocalizations were elicited most consistently by calls of the predatory gray butcherbird (Cracticus torquatus). Some vocalizations from other avian species also elicited Type II vocalizations, and the majority of these were vocalizations from avian predators. Splendid fairy‐wrens are cooperative breeders, and males that responded with Type II vocalizations to playbacks of butcherbird calls tended to be primary rather than secondary males, had larger cloacal protuberances, and were older than those that did not respond. In addition, secondary males that were sons of resident females were more likely than non‐sons to respond with a Type II vocalization. In another playback experiment, females responded similarly to the Type I song and Type II vocalizations of their mates. Although the Type II vocalization is emitted primarily in response to predator calls, it is inconsistent with an alarm call explanation. Patterns of reproductive success among Type II calling males suggest that it does not function as an honest signal of male quality. At present, the function of the vocalization remains anomalous, but indirect fitness benefits may play a role in its explanation.
Avoidance of Chemical Alarm Cues Released from Autotomized Tails of Ravine Salamanders (Plethodon richmondi)
Authors: Hucko Jeffery A. , Cupp Paul V.
Published: March 2003

The ability of animals to detect and avoid areas containing chemical alarm cues from conspecifics is well documented in aquatic species. The ability to detect chemical alarm cues in terrestrial organisms has not been tested until recently. In this study, we tested the ability of the ravine salamander (Plethodon richmondi) to detect and avoid areas containing chemicals released from the autotomized tails of conspecifics and sympatric zigzag salamanders (P. dorsalis). We also ascertained whether any avoidance response could be attributed to the size or sex of the animal. Our results suggest that ravine salamanders avoid substrates containing odors released from the autotomized tails of conspecifics, but not of heterospecific salamanders and that this response occurs independent of the size and/or sex of the animal. By avoiding areas where a conspecific has recently been injured, an organism could reduce its chances of encountering a predator and thus increase its chances of survival.
Social Affiliations within Sperm Whale (Physeter macrocephalus) Groups
Authors: Christal Jenny , Whitehead Hal
Published: March 2003

We examined patterns of affiliation within groups of sperm whales (Physeter macrocephalus), particularly concentrating on how short‐term spatio–temporal associations reflect long‐term relationships. Female and immature sperm whales live in stable, and partially matrilineal, social units. Two or more social units may move together for periods of several days, forming a cohesive group of about 20 animals. We observed that sperm whales in the eastern tropical Pacific quite consistently associated with members of their own social unit more than they did with other animals in their group with whom they did not share a long‐term relationship. There was little evidence for preferred, or avoided, affiliations within social units, except in two large and relatively unstable units. In two well‐studied groups, individuals did not show consistently favoured positions in the foraging rank relative to other members of their social unit. These results indicate the importance of long‐term relationships to female and immature sperm whales, but suggest that relationships are quite homogeneous within social units.
Sexual Dimorphism of Mate Location in the Long‐Toed Salamander Ambystoma macrodactylum columbianum
Authors: Verrell Paul , Strand Nicholas , Hanson Emily
Published: March 2003

In breeding systems characterized by scramble competition among males, theory predicts that the efficient location of mating partners is more important to males than to females as a component of mating success. We experimentally tested in the laboratory the hypothesis that breeding male long‐toed salamanders (Ambystomamacrodactylumcolumbianum), which scramble for mating opportunities, are better able to recognize and locate potential mates than are breeding females. Males were more likely to enter traps containing females than empty traps or traps containing males. Traps containing sponges soiled by females were more likely to attract males than traps containing clean (control) sponges, suggesting that chemical cues may be sufficient for mate location by males. Females were no more likely to enter traps containing males than empty traps. Our results are consistent with the theoretical prediction that selection has been stronger on male long‐toed salamanders than on females in the context of capacity for recognizing and locating potential mating partners.
Experience Affects Female Responses to Male Song in the Variable Field Cricket Gryllus lineaticeps (Orthoptera, Gryllidae)
Authors: Wagner William E. , Smeds Matthew R. , Wiegmann Daniel D.
Published: March 2003

Search theory predicts that females will use information on search costs and the characteristics of potential mates to adjust their search behavior and mate choices. We examined the effect of previous acoustic experience on female mating responses in the variable field cricket Gryllus lineaticeps. Females of this species prefer calling songs with higher chirp rates to those with lower chirp rates. In this study we examined how female responses to male calling songs change with experience by measuring the responses of females to male calls over a sequence of three trials. Females in one group (group I) were exposed to a sequence of three identical low chirp rate songs and females in a second group (group II) were exposed to two identical low chirp rate songs interspersed by a high chirp rate song. Females in group I did not show a significant difference in their responses to the initial and final low chirp rate presentations, whereas females in group II showed a significantly reduced response to the final low chirp rate song. In addition, the degree to which female responses to the initial and final low chirp rate song changed differed significantly between the treatment groups. Thus acoustic experience appears to affect female mating preferences in this species; exposure to either more attractive songs or more variable songs makes normally unattractive songs even less attractive. These results suggest that females do not use a fixed‐threshold search rule in which they mate with any male with a phenotype that exceeds a given threshold. Instead, G. lineaticeps females appear to use a more complex search rule in which they adjust their searching behavior based on the local distribution of male phenotypes.
Negative Association Between Conspicuous Visual Display and Chemosensory Behavior in Two Phrynosomatid Lizards
Authors: Hews Diana K. , Benard Michael F.
Published: March 2003

Communication in one sensory modality can influence communication in others. Lizards in many phrynosomatid species use primarily visual but also chemical signals. The striped plateau lizard, Sceloporus virgatus, exhibits evolutionary loss of a male color signal that in many species is used during aggressive postural displays towards conspecific males. These patches are used similarly in Urosaurus, the sister genus to Sceloporus. We compared a species in which a color signal has been lost, S. virgatus, to a species retaining the ancestral character state of blue abdominal display patches, Urosaurus ornatus, the common tree lizard, to test two hypotheses: (i) conspicuous postural displays that reveal the abdominal patch location are used less in the species that has lost the color patches; and (ii) potential chemical signals are used more in the species with the color loss. We analyzed both visual display behavior (push‐up, full‐show) and chemosensory behavior (tongue flick and nose tap) of male lizards following their introduction to a resident conspecific male in his home terrarium. Resident males performed very low rates of all behaviors, but intruders exhibited sufficient behavior for analysis.

Supporting the first hypothesis, S. virgatus were less likely than U. ornatus to perform full‐show, a display that reveals abdominal skin. Male S. virgatus were more likely to perform push‐up than U. ornatus, although S. virgatus performed push‐up infrequently. Push‐up is a postural display that does not specifically reveal the abdominal patch location. Supporting the second hypothesis, S. virgatus were more likely to perform chemosensory behaviors and performed them at a greater rate than did U. ornatus. Work comparing more closely related species is warranted to determine whether a negative association between conspicuous visual displays and chemosensory behavior is a general pattern.
Importance of Frequency and Temporal Song Matching in Black‐Capped Chickadees: Evidence from Interactive Playback
Authors: Otter Ken A. , Ratcliffe Laurene , Njegovan Milan , Fotheringham James
Published: March 2003

Song‐type matching during territorial contests may allow males of some bird species to direct their signal to a particular receiver. By matching the song‐type and also responding immediately to a rival (temporal matching), a signalling male may indicate his willingness to escalate the contest. Black‐capped chickadees (Poecile atricapilla) sing a single song‐type, but are able to sing this song over a wide range of absolute frequencies. By using interactive playback to instigate and control the level of matching during trials, we investigated whether matching the frequency and the temporal patterning of song escalates contests. Males that were matched for both the frequency and the temporal pattern of their songs during trials escalated contests more than males that were not matched, while males that were only matched temporally had an intermediate response. During trials that consisted of temporal matching only, focal males often shifted frequency to match the playback. Our results confirm that frequency matching and temporal matching using a single song‐type allows graded signalling during aggressive interactions in chickadees.
Sex and the Single Vole: Effects of Social Grouping on Prairie Vole Reproductive Success
Authors: Hodges Karen E. , Mech Stephen , Wolff Jerry O.
Published: March 2003

Prairie voles (Microtus ochrogaster) have a mating system that is primarily monogamous with paired males and females together defending breeding space against intruders of either sex. Breeding success may be affected when other adults intrude on the territorial space of pairs. We conducted an experiment to determine the impact of additional members of either sex on reproductive success of pairs. In laboratory arenas, we formed pairs (1F:1M) and two kinds of triad (2F:1M, 1F:2M). Females in pairs had the highest conception rates, litter sizes and survival of litters. Females in 1F:2M groups had slightly reduced litter sizes and reduced numbers of weanlings, and some females had litters sired by both males. Females in 2F:1M groups had low conception rates and the smallest litters, and >35% of their litters suffered infanticide; in no case did both females become pregnant. Throughout the trials, individuals of the sex doubly represented in triads were more likely to die than were individuals of the sex singly represented. We conclude that there may be fitness costs associated with the presence of unrelated supernumerary adults during gestation and lactation.
Changes in Song Complexity Correspond to Periods of Female Fertility in Blue Grosbeaks (Guiraca caerulea)
Authors: Ballentine Barbara , Badyaev Alexander , Hill Geoffrey E
Published: March 2003

Song complexity is thought to be a sexually selected trait in passerine birds; however, quantifying relevant parameters of song complexity is the first step in testing the theory that song complexity is a sexually selected trait. We show here that blue grosbeak (Guiraca caerulea) males sing a single song type but the properties of that song type vary between renditions. This pattern of song delivery potentially provides females with an opportunity to assess dimensions of song complexity other then repertoire size. Here we characterize song complexity using four measures: (i) element repertoire size, (ii) proportion of distinct song variant, (iii) song versatility, and (iv) syntax consistency. We studied the functional significance of song complexity by comparing measures of song complexity before and after periods of female fertility. We found that male blue grosbeaks sing more song variants, use more versatile arrangements of elements, and maintain more syntax consistency during the fertile period of their social mate than during their social mate's non‐fertile period. These results point to a functional relationship between changes in song complexity and periods of female fertility in this species.