Agonistisches Verhalten, Territorialverhalten und Balz der Zwergtrappe (Tetrax tetrax)

Zusammenfassung 1980–1984 wurden in Südfrankreich und Portugal Untersuchungen zum agonistischen Verhalten, Territorialverhalten und zur Balz der ZwergtrappeTetrax tetrax durchgeführt.Während der Fortpflanzungsperiode kommt es zwischen Zwergtrappen- häufig zu agonistischen Auseinandersetzungen. Ausdruck aggressiver Erregung ist enges Anlegen des Halsgefieders, Langstrecken des Halses, und nur beim Aufrichten und dachartiges Falten der Schwanzfedern. Aggressive Verhaltensweisen sind Drohen durch Hinlaufen oder -fliegen zu Reviereindringlingen, seitliches Drohen gleichstarker , und nur, wenn Verhaltensweisen niedrigerer Intensität nicht zur Unterlegenheit eines der Rivalen führen, Schnabelkämpfe.Rufen dient der Markierung eines Reviers. Die Intensität des Rufens wird durch die Anwesenheit von nicht beeinflußt, die Anwesenheit fremder nahe der Reviergrenze führt jedoch zu einem deutlichen Anstieg. Die Rufbewegung macht eine gewisse optische Signalwirkung, vor allem auf kurze Distanz, zusätzlich zur akustischen Wirkung, wahrscheinlich.Fliegende erzeugen mit den Schwingen (besondere Struktur der 7. Handschwinge) ein pfeifendes Geräusch, das während der Fortpflanzungszeit Bedeutung in der innerartlichen Kommunikation hat. Es zeigt sowohl als auch den Anflug eines weiteren an und löst damit territoriale bzw. aggressive Verhaltensweisen oder Flucht aus. Weitere Bedeutung erlangt es als Element des Territorialen Flügelschlagens und der Sprungbalz.Über ihrem Revier fliegen territoriale stets mit leicht hochgebogenem Kopf und verhaltenen, flachen Flügelschlägen. Deutungen dieses Fluges als Imponierflug zur besseren Darstellung des auffällig gefärbten Halsgefieders bzw. als Suchflug zum leichteren Auffinden und Verjagen von Reviereindringlingen werden diskutiert.Territoriales Flügelschlagen beginnt mit Fußtrampeln, das sich beschleunigt und in einen Ruf überleitet. Gleichzeitig schlägt das dreimal sehr schnell und flach mit den Flügeln, hebt jedoch nicht vom Boden ab. Alle Elemente des Verhaltens sind deutlich zu hören. Der Verstärkung der beim Fußtrampeln erzeugten Klopfgeräusche dienen Balzplätze, die entweder auf akustisch besonders geeignetem Boden angelegt oder durch das Fußtrampeln der sekundär verbessert werden.Territoriales Flügelschlagen wird ausschließlich in niedrigen Lichtintensitäten während kurzer Zeit in der Morgen- und Abenddämmerung gezeigt. Die Anwesenheit von hat keinen Einfluß auf seine Intensität. Es ist eine territoriale Verhaltensweise mit akustischem Signal und wird als ritualisiertes Anlaufen gegen einen Reviereindringling bzw. ritualisiertes Auffliegen eines Revier- zum Eindringling hin gedeutet. Optische Komponenten kommen in der deckenden Vegetation kaum zur Geltung. können wegen der relativ geringen Reichweite der Signale nicht angelockt werden.Sprungbalz tritt zeitlich streng getrennt vom Territorialen Flügelschlagen in wesentlich höheren Lichtintensitäten auf; seine Intensität hängt ab von Kontakten zu . Sie ähnelt zwar in der Ausführung dem Territorialen Flügelschlagen, der Vogel hebt sich jedoch während der langsameren Flügelschläge durch einen Sprung vom Boden ab, und das Fußtrampeln ist wesentlich weniger intensiv. Charakteristische Flügelbewegungen während des Balzsprunges exponieren schwarzweiße Gefiederpartien bis in 65 cm Höhe. Sprungbalz erhöht im Vergleich zu Territorialem Flügelschlagen stark die optische Auffälligkeit eines ; die Sprunghöhe garantiert zusammen mit der Lage der Balzplätze bei geringstmöglichem Energieaufwand eine maximale Sichtbarkeit des über der umgebenden Vegetation. Sowohl die zeitliche Korrelation der Sprungbalz mit den Aktivitäten der als auch die Art der Interaktionen mit während Sprungbalzphasen machen deutlich, daß diese Verhaltensweise ins Paarungsrevier zieht.Das Hennenjagen dient der Stimulierung der zur Kopulation. Das läuft in charakteristischer Körperhaltung schnell hinter einem her, hat dabei den Kopf tief in die aufgerichtete Halskrause eingezogen, hält oft ruckartig an und ruft unter Zurseitewerfen des Kopfes. Kopulationen sind sehr kurz. Offensichtlich kann das Hennenjagen die sonst sehr ausgeprägte Abwehr des gegen das unterdrücken und zur Kopulationsbereitschaft führen. Die Kopulation selbst jedoch hebt diesen Effekt wieder auf, so daß nach 1–2 Sekunden das abwehrt oder flieht.

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Agonistic behaviour, territorial behaviour and courtship display of the Little Bustard (Tetrax tetrax)

Summary From 1980 to 1984 studies were made of the agonistic, territorial and courtship behaviour of the Little Bustard in Southern France and Portugal. The behaviour patterns are described in detail, the signals involved are analysed, and factors which could have led to their evolution are discussed.In the reproductive period agonistic encounters between males happen remarkably often. Aggressive excitement is expressed in both sexes by compression of the neck-feathers and stretching of the neck, and in the female by the erection and lateral folding of the tail-feathers. There are several kinds of threat behaviour in territorial encounters: running or flying towards intruders; lateral threat behaviour (if both males are of similar strength); and bill-fighting which only occurs if aggressive behaviour of a lower intensity has not led to the submission of one of the rivals. Calling is a territorial behaviour and serves to mark a territory. The frequency of calls is not affected by the presence of females, but the presence of other males close to the territory borders can result in a marked increase in calling frequency. In addition to the acoustic signal, the call involves a sharp neck-jerk which may act as an optical signal, at least over short distances.In flight males produce a whistling sound by means of the specially adapted 7th primary feather on their wings. This sound has important meaning in intraspecific communication during the reproductive period: it announces a flying male to other males as well as to females, and causes territorial and aggressive behaviour, or fleeing of these birds. The flight sound is also an important element of the behaviour patterns territorial wingbeat display and jumping display. Within their territories males always fly with the neck raised at a slight angle and with suppressed, shallow wing-beats. Two interpretations of this flight are discussed: that it serves to advertise the conspicuously coloured neck-feathers in a display; or that it is a search flight for locating and chasing-off intruders.Territorial wingbeat display begins with an accelerating foot-stamping and leads into a call. During the call the male performs three very fast, whistling wing-beats but remains on the ground. The combined elements, foot-stamping, calling and whistling wings, produce a unique and distinctive acoustic signal. The foot-stamping is only performed at special display sites where the sound is amplified by the substrate structure. At such sites, the soil typically has trapped pockets of air below a compacted surface which may result from the repeated defecating and stamping of the male on the same spot. Territorial wingbeat display behaviour is only performed for short periods in low light intensities at dawn and dusk. The presence of females has no effect on the intensity of the behaviour which serves a territorial function. It is interpreted to be a ritualisation of the aggressive running or flying of a territorial male towards an intruder. Optical elements of this behaviour cannot have much importance because the body and wings of the bird are rarely visible above the vegetation. Territorial wingbeat display behaviour cannot be seen over long distances and from this reason cannot serve to attract females into a males territory.Jumping display is only performed at much higher light intensities than territorial wingbeat display so the two never occur at the same time of day. The intensity of the behaviour increases markedly in the presence of females in sharp contrast to the territorial wingbeat display. The jumping display is performed in a similar way to the territorial wingbeat display except that the foot-stamping is much less intensive, the wing-beats are slower, and the bird jumps off the ground during the wing-beats. During the jumping display the black and white patterns on the body and wings are clearly visible and the behaviour increases the conspicuousness of the male markedly. The jump, advertising the wing-pattern up to a height of 65 cm, together with the specific location of the display site, ensures that maximum visibility of the male above the vegetation is achieved at minimum energetic cost. Activities of the females and their interactions with males during the jumping periods indicate that this behaviour serves to attract females to the males territory.The chasing of females is also a courtship behaviour and serves in stimulating and preparing females for copulation. In a characteristic posture with the head retracted into the neck-collar, the male rapidly runs behind the female, repeatedly stopping abruptly and calling whilst throwing its head and body sideways. Copulations are performed very quickly and only happen after a female has been chased for some time. Under certain preconditions chasing suppresses the aggressive and defence behaviour of the female which normally characterises encounters with males, and thus leads to readiness for copulation. Copulation itself removes this effect and after only one or two seconds aggression leads to the escape of the female.

     

O-Glycosylhydrolases of Marine Filamentous Fungi: β-1,3-Glucanases of Trichoderma aureviride

The ability to produce extracellular O-glycosylhydrolases was studied in 14 strains of marine filamentous fungi sampled from the bottom sediments of the South China Sea. The following activities were detected in the culture liquids of the fungi: N-acetyl--D-glucosaminidase, -D-glucosidase, -D-galactosidase, -1,3-glucanase, amylase, and pustulanase. -1,3-Glucanases were isolated by ultrafiltration, hydrophobic interaction chromatography, and ion exchange chromatography, and their properties were studied. Data on products of enzymatic digestion of laminaran, absence of transglycosylation activity, and the pattern of action of natural inhibitors confirmed that -1,3-glucanase belonged to the exo type. Inhibitor analysis demonstrated the role of a thiol group and tryptophan and tyrosine residues in the catalytic activity.     

Yeast ribosomal proteins

Summary Homology maps between bacteriophages 81, 80 and were constructed on the basis of electron microscope observation of DNA heteroduplexes. In 81/80 heteroduplex, the left half and the right terminal region of 13% the total molecular length were highly homologous, while the remaining region covering the early gene cluster was entirely nonhomologous. In 81/ heteroduplex, high-degree homologies were detected at the left 14% terminal region covering the head gene cluster, the central 3.8% region covering the att-int-xis region and the 1.3% Q homology region. Low-degree homologies of shorter length were scattered at the tail gene cluster, b2 region, cIII region, PQ region and SR region. Comparing our results with the homology maps of other lambdoid phages reported by Simon et al. (1971) and Fiandt et al. (1971), a phylogenic relation of 81 to other lambdoid phages and the role of recombination in the course of divergence of lambdoid phages are discussed.     

Histochemical and immunochemical studies on mammalian striated muscle fibres

Summary In 15 rabbit and 2 human distinct types of striated muscle, it was shown that all fibres classified as type I (red) by NADH-diaphorase and myofibrillar ATPase reaction exhibit intense fluorescence when treated with a FITC-labelled antibody against human pectoral actomyosin. Type II (white) fibres showing minimal fluorescence, an intermediate fibre type can be differentiated by all three methods. In the rabbit, all three fibre types are found, whereas, in the human muscles studied, only type I and intermediate type fibres were found.Abbreviations ATPase adenosintriphosphatase (EC 3.6.1.3) - anti-PAM anti-human-pectoralis actomyosin - FITC fluoresceine-isothiocyanate     

Bipolar Manifestation of Cataleptic Reactions in Rats

Breeding of GC rats for the predisposition to cataleptic freezing has increased not only the frequency, intensity, and duration of freezing, but also the proportion of irritable or nervous rats with enhanced anxiety, defensive behavior with vocalization, jerky running, and jumpiness. An increased amplitude of the startle reflex is a correlate of this nervousness. The results of the comparison of some behavioral characters in the nervous and freezing GC rats, as well as in S₁ and S₂ offspring from homogeneous crosses between nervous and freezing GC rats suggest that cataleptic freezing and nervousness are two poles of the same bipolar catatonic reaction. They have a common mechanism, with the alternative or preferential expression of one particular form of the reaction is determined by the external and internal environments or the set of modifier genes in the given individual.     

Identification and DNA sequence analysis of a γ-type gliadin cDNA plasmid from winter wheat

Summary Recombinant cDNA plasmids possessing the coding sequences for the -type gliadins were isolated from a cDNA library prepared from wheat seed poly (A⁺) RNA. One of these plasmids, pGliB48, specifically hybridizes to poly (A⁺) RNA molecules 1 400–1 500 bases in length that direct the synthesis of polypeptides at 38 Kd and 46 Kd, the latter size characteristic of the -type gliadins. The cDNA sequence of pGliB48 was determined and encompasses the 3 untranslated region as well as 245 amino acids from the C-terminus of the -type gliadin polypeptide. The 5-end of the DNA coding sequence consists of a tandem repeat unit composed of eight amino acids. Localized regions of homology are observed for the /-type and -type gliadin cDNA sequences.     

Genetic characterization of a new splice variant of the β2 subunit of the voltage-dependent calcium channel

This study reports a novel splice variant form of the voltage-dependent calcium channel ₂ subunit (_2g). This variant is composed of the conserved amino-terminal sequences of the _2a subunit, but lacks the -subunit interaction domain (BID), which is thought essential for interactions with the ₁ subunit. Gene structure analysis revealed that this gene was composed of 13 translated exons spread over 107 kb of the genome. The gene structure of the ₂ subunit was similar in exon-intron organization to the murine ₃ and human ₄ subunits. Electrophysiological evaluation revealed that _2a and _2g affected channel properties in different ways. The _2a subunit increased the peak amplitude, but failed to increase channel inactivation, while _2g had no significant effects on either the peak current amplitude or channel inactivation. Other subunits, such as ₃ and ₄, significantly increased the peak current and accelerated current inactivation.     

Polymorphism of the HLA DR1 haplotype in the Israeli population investigated at the serological,cellular, and genomic levels

In the present report, we used serological, cellular, and restriction fragment length polymorphism (RFLP) to investigate the DR1 haplotype in the Israeli population. We describe an Israeli homozygous typing cell (HTC), HLA-DwLVA, which defines a new lymphocyte-activating determinant associated with Bw65, DR1 and distinct from Dwl. The parents of this donor, non-Ashkenazi Algerian Jews, are first cousins and share HLA-Cw8, Bw65, BfS, DR1, DQw1, DPw4. No specificity could be assigned to HLA-DwLVA using the 91 Ninth Workshop HTCs. Two families and forty unrelated DR1 individuals were studied with DwLVA and a panel of DR1/Dw1 HTCs. HLA-DwLVA showed segregation as a single determinant within families. This new specificity was present in 24 out of 40 (60%) unrelated DR1 individuals, indicating that in the Israeli population DwLVA is the main lymphocyte-defined determinant associated with the serologically defined DRI specificity, in contrast to non-Jewish Caucasoids where DR1 is significantly associated with Dw1. The vast majority of DwLVA-positive carriers were also Bw65 carriers, indicating that Bw65, DR1, DwLVA may represent a typical allele combination in the Israeli population. The RFLP analysis established the correlation of certain RFLPs with Dw1 and DwLVA. In addition, we describe a cluster of RFLPs that may correspond to a new Dw subtype associated with DR1, for which no serological and cellular reagents have been described so far.     

Measuring the Arousal Space of a Sit-and-Wait Predator: A Comparison of Predictive Models

The present study set out to compare two predictive models, Holling (1966) and Hardman and Turnbull (1980), to describe the arousal space for the aquatic sit-and-wait predator, Ranatra dispar. When tested in the horizontal plane the fit of Holling's model was good, although a better fit was achieved by using the untransformed angle of prey to body axis term . The second, multiple regression model, gave smaller residuals for low food deprivation periods but larger for longer periods. In the vertical plane the Holling model was unsatisfactory. It is suggested that the changes in number and size of ommatidia from dorsal to ventral region of the eye is largely responsible. A multiple regression model is described that predicts the arousal field of R. dispar in the vertical plane. It is suggested that the general applicability of such models to other visual predators is restricted if apparent hunger effects are not included in their development.     

The spermatozoon of Oikopleura dioica Fol (Larvacea,Tunicata)

Summary The spermatozoon of Oikopleura dioica is about 30 m long, with a spherical head, about 1 m wide, a 3 m long and 1 m wide midpiece, and a 25 m long tail with a tapered end piece. The head contains a nucleus with the chromatin volume limited to about 0.1 m³. A small acrosome is found in an anterior inpocketing, and a flagellar basal body in a posterior inpocketing of the nucleus. The midpiece contains a single mitochondrion with the flagellar axoneme embedded in a groove along its medial surface. The flagellar axoneme has the typical 9 + 2 substructure, and the basal body the typical 9+0 substructure. A second centriole and special anchoring fibres are absent.     

Multi-loop representation of the segmental muscle stretch reflex

Bees were trained to react to differences both in the size and in the degree of greyness of discs. To measure the differential sensitivity on these parameters, differences in size and shade of grey (-intervals) were established such as lead to a specific choice reaction (Fig. 3). The -intervals may be described for both parameters by Weber's rule (Fig. 4). The main result is the following relationship between the differential sensitivity and the equivalence curve as defined by cross modality matching. The bee treats two discs, which differ from a reference disc in diameter or in degree of greyness, as equivalent when both differ from the reference disc by an equal number of -intervals (Fig. 6). The choice reactions between the reference disc and the discs of the equivalent pair are the same for these parameters. This does not hold for another parameter (Fig. 7A and B). Problems of infering from the -intervals to the differential sensitivity are then discussed.     

Relationship between the grain pattern in the wood,domain pattern and pattern of growth activity in the storeyed cambium of trees

Summary The relationship between the arrangement of cell events occurring in cambium in a definite configuration and the grain pattern of wood was investigated. Taking into consideration the growth activity of fusiform cell ends, a model of a migrating morphogenetic wave determining an event configuration was made. Waves of length =1 m for the periods T=2 years and T=3 years and waves of lengths =l m and =0.04 m for the period T=10 years were considered. On the model, events from successive annual rings, conventionally comprising 10 cell layers each, were summed. In this way, event maps were obtained. For wave =4 mm, the domain pattern on the modelled map was compatible with the grain pattern. The domain pattern for the wave =1 m was impossible to recreate because the wave migrated too fast. In this case, the pattern of event configuration, incompatible with the grain pattern, formed microareas, which were not domains.     

Lumenal calcium modulates unitary conductance and gating of a plant vacuolar calcium release channel

The patch clamp technique has been used to investigate ion permeation and Ca²⁺-dependent gating of a voltage-sensitive Ca²⁺ release channel in the vacuolar membrane of sugar beet tap roots. Reversal potential measurements in bi-ionic conditions revealed a sequence for permeability ratios of Ca²⁺ Sr²⁺ Ba²⁺ > Mg²⁺ K⁺ which is inversely related to the size of the unitary conductances K⁺ Mg²⁺ Ba²⁺ > Sr²⁺ Ca²⁺, suggesting that ion movement is not independent. In the presence of Ca²⁺, the unitary K⁺ current is reduced in a concentration- and voltage-dependent manner by Ca²⁺ binding at a high affinity site (K _0.5 = 0.29 mm at 0 mV) which is located 9% along the electric field of the membrane from the vacuolar side. Comparison of reversal potentials obtained under strictly bi-ionic conditions with those obtained in the presence of mixtures of the two ions indicates that the channel forms a multi-ion pore. Lumenal Ca²⁺ also has an effect on voltage-dependent channel gating. Stepwise increases of vacuolar Ca²⁺ from micromolar to millimolar concentrations resulted in a dramatic increase in channel openings over the physiological voltage range via a shift in threshold for channel activation to less negative membrane potentials. The steepness of the concentration dependence of channel activation by Ca²⁺ at –41 mV predicts that two Ca²⁺ ions need to bind to open the gate. The implications of the results for ion permeation and channel gating are discussed.We thank Ian Jennings for writing and implementing some of the software used in this study and Anna J. Bate for technical assistance. The work was supported by grants from the Biotechnology and Biological Sciences Research Council to E.J. (PDF/14) and DS (PG87/529).     

The synthesis of oligosaccharides by the reversed hydrolysis reaction of β-glucosidase at high substrate concentration and at high temperature

Summary In the presence of -glucosidase from almond, a 90% glucose solution gave four kind of -linked glucose-disaccharides. The yield increased as the concentration of glucose was increased and as the reaction temperature was raised. The maximum yield of disaccharides from 90% glucose solution was 40% at 55°C.     

Progressively developed myocardial apoptotic cell death during late phase of reperfusion

Myocardial apoptosis is primarily triggered during reperfusion (R). The aim of this study was to test the hypothesis that R-induced apoptosis develops progressively during the late phase of R, and that R-induced apoptosis is associated with changes in expression of anti- and pro-apoptotic proteins and infiltrated inflammatory cells. Thirty-one dogs were subjected to 60 min of left anterior descending coronary occlusion followed by 6, 24, 48, and 72 h R, respectively. There was no group difference in collateral blood flow, measured by colored microspheres during ischemia. Necrotic cell death (TTC staining) was significantly increased during R, starting at 27 ± 2% at 6 h R and increasing to 41 ± 2% at 24 h R. There was no further change at 48 (37 ± 3%) and 72 (36 ± 6%) h R, respectively. TUNEL positive cells (% total normal nuclei) in the peri-necrotic zone progressively increased from 6 (26 ± 2^*) to 24 (38 ± 1^*), 48 (48 ± 3^*) and 72 (59 ± 4^*) h R, respectively. The number of detected TUNEL positive cells at these time points was consistent with an increased intensity of DNA ladders, identified by agarose gel electrophoresis. Compared with normal tissue, western blot analysis showed persistent reduction in expression of anti-apoptotic protein Bcl-2 from 6 (16 ± 0.8%^*) to 72 h R (78 ± 2%^*), and increase in expression of pro-apoptotic proteins including Bax from 6 (30 ± 3%^*) to 72 h R (66 ± 3%^*), and p53 from 6 (12 ± 1%^*) to 72 h R (91 ± 2%^*), respectively. Immunohistochemical staining revealed that infiltrated neutrophils (mm² myocardium) were significantly correlated with development of necrotic and apoptotic cell death from 6 to 24 h R, respectively (P < 0.05), while large macrophage infiltration seen during 48 to 72 h R were correlated with apoptotic cell death (P < 0.05). These results indicate that 1) necrosis peaked at 24 h R when apoptosis was still progressively developing during later R; 2) changes in Bcl-2 family and p53 proteins may participate in R-induced myocardial apoptosis; 3) inflammatory cells may play a role in triggering cell death during R. ^* P < 0.05 vs. normal nuclei and tissue; P < 0.01 vs. 6 h R.     

Nuclear behavior in multinucleate Schizophyllum commune germlings

Summary The ultrastructure of a fir morphological mutant containing multinucleate cells is described in Schizophyllum commune. The germlings of basidiospores which arose from mating fir with wild-type mycelium were studied in culture by phase contrast microscopy to elucidate behavior of multinucleate cells. Nuclear division appeared synchronous from two nuclei yielding four progeny through six nuclei producing twelve products, beyond which loss of synchrony was indicated. Compensatory nuclear migration into an anucleate cell was presumed during synchronous division of nuclear aggregates in the adjacent cell of an individual germling. The migrant nucleus eventually returned to the cell of origin. However, the return route was not via the central pore of the septum but rather occurred at the juncture of the cross-wall with the germling-periphery. Ultrastructure of a partial septum in fir which could accommodate nuclear passage of this sort is described.     

Interaction of cytochrome c L with methanol dehydrogenase from Methylophaga marina 42:

The reaction of methanol dehydrogenase with cytochrome c _L from Methylophaga marina and the reactions of the non-physiological substrates, Wurster's blue and ascorbic acid, with both proteins were studied as a function of temperature (4–32 °C), pressure (1–2000 bar) and ionic strength using the optical high pressure stopped-flow method. The thermodynamic parameters H, S and V were determined for all reactions where electron transfers are involved. These data allowed the determination of the Maxwell relationships which proved the internal thermodynamic consistency of the system under study. A conformational change on the cytochrome c _L level was deduced from both breaks in the Arrhenius plots and the variation of the V with temperature.Abbreviations MOPS 4-morpholinepropanesulfonic acid - CHES 2-(cyclohexylamino)ethanesulfonic acid - MDH methanol dehydrogenase - EDTA ethylenedinitrilotetraacetic acid disodium salt - BTB bromothymol blue (3,3-dibromothymolsulfoneph-thalein) - PQQ 2,7,9-tricarboxy-lH-pyrrolo-[2,3f]quinoline-4,5-dione - cytochrome c _HH mammalian horse heart cytochrome c     

Isolation of a rat immune response gene identical to an alleged mouse A class II β-chain pseudogene

A human HLA-DQ -chain cDNA was used as a probe to identify and isolate a rat major histocompatibility antigen -chain gene from a genomic library constructed in the vector Charon 28 using Wistar rat DNA (RT1 ^u). The isolated exon of the rat gene (RT1.B ₂) encoding a -chain second domain was found to share 93% nucleotide homology with a mouse A ₂ exon. Although the genomic organization of this gene is consistent with the hypothesis that it represents a pseudogene, the remarkable preservation of a specific sequence favors the view that this class II antigen -chain gene has retained its coding function.     

Effect of deglycosylation on the properties of β-fructofuranosidaseP-1 fromAureobasidium sp. ATCC 20524

Summary Most of the carbohydrate moiety of -fructofuranosidaseP-1 fromAureobasidium sp. ATCC 20524 was removed by endo--N-acetylglucosaminidase F. A subunit of 94000 Da was observed in SDS-PAGE after deglycosylation. TheK _m value for sucrose was not changed by deglycosylation but the stability at pH 4–5 and 50°C was decreased. The deglycosylated enzyme was more sensitive to proteases such as pronase E and subtilisin than the native enzyme. It is considered that the carbohydrate moiety of -fructofuranosidaseP-1 contributes to the stability of the enzyme but is not essential in its catalytic function.     

Structure and evolution of the HLA Class II SXβ gene

The class II major histocompatibility complex antigens are cell-surface heterodimers consisting of an a and a chain. Cosmid cloning has shown that the three families of clas II antigens, DR, DQ, and DP, are encoded within the HLA-D region of chromosome 6 as a series of discrete gene clusters. The DP cluster contains two pairs of a and genes, one of which encodes the biochemically-defined DP antigen. In order to assess whether the other two genes, SXa and SX, are also expressed, potential coding regions have been subcloned and sequenced. The SX3 gene is shown to contain region closely homologous to all six exons of DP. A 1 bp deletion in the 2 exon, also observed for the SX4 allele, causes a translation frameshift, suggesting that SX is a pseudogene. However, all the other exons, as well as their splice sites and the putative promoter region, appear to be intact.