Song Functions in Nonduetting Gibbons: Evidence from Playback Experiments on Javan Gibbons (<Emphasis Type="Italic">Hylobates moloch</Emphasis>)

Territorial, pair-living primates usually perform long-distance calls as duets in which adult males and females coordinate their calls. Previous studies using playback experiments have shown that gibbon duets convey information about the status of the caller (location, familiarity, sex of the caller, and paired status) and gibbons use this information to respond to achieve several nonmutually exclusive functions, including intragroup contact, territorial defense, and pair-bond advertisement and strengthening. However, not all pair-living gibbons duet, and it is unclear whether the same results should be expected in nonduetting species. We conducted song playback experiments (N = 47 trials) to test hypotheses about song functions in nonduetting gibbons on two groups of wild Javan gibbons (Hylobates moloch) in the Gunung Halimun-Salak National Park, Indonesia. Javan gibbons initiated movement toward the speaker more quickly in response to songs broadcast in the center of the territory, stranger songs, and songs of unpaired individuals than to songs at the border, neighbor songs, and songs from paired individuals. These results suggest that Javan gibbons can localize songs, and that Javan gibbon songs transmit information about the identity and paired status of the caller. Our results imply that Javan gibbon solo songs are likely to function for territorial defense and pair-bond advertisement like duets in other primates.     

Morphological Comparison of Meloidogyne Female Head Structures,Perineal Patterns,and Stylets

The external morphology of female heads of three populations of each of two cytological races of Meloidogyne hapla (race A-meiotic, race B-mitotic) and single populations of M. arenaria, M. incognita, and M. javanica was compared by light (LM) and scanning electron microscopy (SEM). Perineal patterns of all nine populations were observed with a LM and then examined with a SEM. In addition, female stylets of each population were excised, viewed with a SEM, and compared with observations made with a LM. Head morphology of the females, including shape of medial and lateral lips, expression of sensilla, and head annulation, was distinct for each species, each race of M. hapla, and each population of M. hapla race A. The morphology of a given perineal pattern appeared similar with the SEM and the LM. The SEM emphasized surface details, whereas the LM revealed subcuticular structure as well. Stylet morphology was unique for each species but similar in all populations of M. hapla. There were differences between species in the shape of the cone, shaft, and knobs and in the distance of the dorsal esophageal gland orifice from the stylet knob base. Several of the morphological characters first detected in the SEM were seen subsequently with the LM and are helpful in species identification.     

Calcium lonophore-induced stimulation of secretory activity in Chlamydomonas reinhardii

The cell-wall lysin in gametes from Chlamydomonas reinhardii which under normal mating conditions is activated by flagellar cell contact was found to be susceptible to stimulation by the antibiotic ionophore A 23187 provided that CA²⁺ was included in the medium. Ionophore-induced release of the cell-wall lysin did not deend on the mating type or the gametic state of the cells. Vegetative cells which normally do not exhibit any mating capacity reacted with cell-wall lysis like gametes stimulated by cell contact.Ionophore-dependent Ca²⁺-transfer across the cell membranes generated a signal for cell-wall lysis only in cells with intact flagella. Deflagellated cells did not respond to A 23187 before regeneration of the amputated organelles. Another indication for a possible role of flagella in Ca²⁺-mediated cell-wall lysis was obtained from a conditional flagellar-assembly mutant of C. reinhardii which had been isolated and described by Huang et al. (1977). Upon shift-up the mutant strain immediately became unresponsive to A 23187 and Ca²⁺ but regained susceptibility soon after being retransferred to permissive conditions (20°C).     

Morphology and function of the antennular joint and its strand organ,instrumental to gravity reactions in the spiny lobster Panulirus argus (Crustacea,Decapoda)

Summary The one-point joint linking the antennula with the carapace in Panulirus argus is described. A strand organ is activated when the antennula is moved in the vertical plane. Its structure, function, and regeneration after severance were investigated.The implications of this system are discussed, starting from the findings that the strand organ counteracts the statocyst (located in the antennula) in such a way that gravity reactions occur only if the body changes its position with respect to gravity.The work was supported by grants from the Max-Planck-Gesellschaft (Hedwig Schöne), the National Science Foundation of the U.S.A., the American Philosophical Society, and the Cecil Montgomery-Moore Fellowship of the Bermuda Biological Station. Contribution No. 836 of the Bermuda Biological Station     

Über den Faserverlauf in den Rostralzähnen des Sägerochens Pristis

Zusammenfassung Die Untersuchung fertiger Rostralzähne von Pristis spec. zwischen gekreuzten Polars ergab zunächst Übereinstimmung mit den Angaben von Gebhardt (1900) und W. J. Schmidt (1924): d. h. in den röhrigen Elementen des Trabeculardentins verlaufen die Kollagenfasern vorwiegend nach der Länge des Zahnes, im Fachwerk der trennenden Septen aber quer dazu. Jedoch gibt es daneben noch Fasern, welche die in der einzelnen Röhre radial ausstrahlenden Dentinröhrchen begleiten, und andere, welche die genannten Längsbündel umgürten. Das Vorkommen von Längsbündeln auch in den Septen (Gebhardt 1900) konnte bestätigt werden.Die meist schwach ausgeprägten negativen Polarisationskreuze in einem Teil der Trabeculardentinröhren sind, wie schon W. J. Schmidt (1924) betonte, auf Neigung der Kollagenfasern in Tangentialebenen der Röhrchen zu beziehen, nicht auf negative Grundsubstanz (Gebhardt 1900); denn diese Polarisationskreuze bleiben auch nach dem Entkalken erhalten.Die kräftiger ausgeprägten Polarisationskreuze, welche den ganzen Querschnitt der Röhrenwand durchsetzen, bezeugen stärkere tangentiale Neigung der Fibrillen; sie lassen außerdem lamelläre Schichtung der Röhrenwand erkennen, die auch auf dem Radialschliff nachweisbar ist. Der von Bradford (1957) behauptete Unterschied gegenüber Trabeculardentin hinsichtlich Schichtung besteht also nicht. Alle geschilderten Kollagenfasern sind verkalkt (vornehmlich phosphorsaurer Kalk), auch die groben in die TrabeculardentinrÖhren aufgenommenen (gegen Engel 1910); denn das Polarisationsbild bleibt auch nach der Mineralisierung in allen Einzelheiten erhalten (bei umgekehrtem Vorzeichen).Daß es sich bei den Längsfasern nicht um Stäbchen aus schmelzartiger Substanz handelt, wie neuestens Bradford (1957) vertritt, sondern um Kollagenfasern, erweist — in Übereinstimmung mit der polarisationsoptischen Deutung von Gebhardt (1900) und W. J. Schmidt (1922) und der durch Engel (1910) erforschten Ontogenese — der positive Ausfall der Phenolreaktion.     

Functional characterization of a natural retinoic acid responsive element.

Retinoic acid receptor (RAR) and thyroid hormone receptor (T3R) are thought to bind as dimers to a T3 responsive element (T3REpal) comprised of inverted repeats of the half-site motif GGTCA. However, a RA responsive element (beta RARE) was previously identified in the promoter of the RAR beta 2 gene which contains two direct repeats of the motif GTTCA spaced by a six nucleotide gap. We now demonstrate the ability of RAR alpha, beta and gamma to bind to and transactivate through this element and that the two direct repeats comprise the beta RARE. Surprisingly, the GTTCA motifs rearranged to form a palindrome do not confer RA responsiveness to a heterologous promoter. Furthermore, no significant level of transactivation is detected by ligand-activated RAR through the Moloney murine leukaemia virus T3RE, which comprises two direct repeats of the sequence GGTCA/C spaced by a five nucleotide gap. Similarly, T3R does not induce gene expression through the beta RARE. This study establishes the preference of T3R to transactivate through direct repeats spaced by a five nucleotide gap as opposed to a six nucleotide gap. In contrast, RAR appears to be more flexible with respect to spacing requirements between repeats, although higher levels of transactivation are obtained through direct repeats spaced by a six nucleotide gap. Interestingly, although some elements mediate either RA or T3 induction, changing a single nucleotide in the MoMLV T3RE with a five nucleotide spacing creates a promiscuous RA/T3 responsive element.     

PGRL1 Participates in Iron-induced Remodeling of the Photosynthetic Apparatus and in Energy Metabolism in Chlamydomonas reinhardtii

PGRL1 RNA and protein levels are increased in iron-deficient Chlamydomonas reinhardtii cells. In an RNAi strain, which accumulates lower PGRL1 levels in both iron-replete and -starved conditions, the photosynthetic electron transfer rate is decreased, respiratory capacity in iron-sufficient conditions is increased, and the efficiency of cyclic electron transfer under iron-deprivation is diminished. Pgrl1-kd cells exhibit iron deficiency symptoms at higher iron concentrations than wild-type cells, although the cells are not more depleted in cellular iron relative to wild-type cells as measured by mass spectrometry. Thiol-trapping experiments indicate iron-dependent and redox-induced conformational changes in PGRL1 that may provide a link between iron metabolism and the partitioning of photosynthetic electron transfer between linear and cyclic flow. We propose, therefore, that PGRL1 in C. reinhardtii may possess a dual function in the chloroplast; that is, iron sensing and modulation of electron transfer.