Odor tracking flight of male Manduca sexta moths along plumes of different cross-sectional area

Males of the hawkmoth, Manduca sexta, track wind-borne plumes of female sex pheromone by flying upwind, while continuously turning from side-to-side and changing altitude. Their characteristic “zigzagging” trajectory has long been thought to result from the interaction of two mechanisms, an odor-modulated orientation to wind and a built-in central nervous system turning program. An interesting and as of yet unanswered question about this tracking behavior is how the cross-section of an odor plume or its clean-air “edges” affects moths’ odor tracking behavior. This study attempts to address this question by video recording and analyzing the behavior of freely flying M. sexta males tracking plumes from pheromone sources of different lengths and orientations with equal odor concentration per unit area. Our results showed that moths generated significantly wider tracks in wide plumes from the longest horizontally-oriented sources as compared to narrower point-source plumes, but had relatively unaltered tracks when orienting to plumes from the same length sources oriented vertically. This suggests that in addition to wind and the presence of pheromones, the area of the plume’s cross section or its edges may also play an important role in the plume tracking mechanisms of M. sexta.     

Bioassay of mosquito iridescent virus of Aedes taeniorhynchus in cell cultures of Aedes aegypti.

A bioassay of mosquito iridescent virus (MIV) of Aedes taeniorhynchus was developed using cell cultures of Aedes aegypti. The dilution end point technique was based on the occurrence of cytopathic effects which were optimum at 31°C. Peleg's A. aegypti cell line was more sensitive and reliable than Singh's A. aegypti cell line for infectivity titration of the “R” and “T” strains of MIV. The highest tissue culture infectivity dose 50s (TCID₅₀) were elicited by virion:cell ratios of approximately 10. TCID₅₀ titers were significantly reduced by virus neutralization with either homologous or heterologous antiserum to either RMIV or TMIV. The virus propagated in either cell line was not infectious to A. taeniorhynchus larvae, or to the respective cells from which the virus was produced. All plaque assay attempts were unsuccessful.     

Modification of prey-catching behavior by learning in the common toad (Bufo b. bufo [L], Anura,Amphibia): Changes in responses to visual objects and effects of auditory stimuli

An attempt to train common toads (Bufo b. bufo) to make the turning movements associated with prey-catching in response to a tone (1000 Hz, 90 dB) was unsuccessful. However, some toads learned to discriminate food that had been made unpalatable from palatable food of identical appearance, when the former was accompanied by the auditory stimulus. By making the prey unpalatable flight behavior could be induced in toads presented with a housefly (Musca domestica). On the other hand, toads could be trained to exhibit prey-catching behavior when shown predator objects 30 cm wide and 60 cm high (at a distance of ca. 50 cm). The toads also learned to snap at motionless, unscented food in certain surroundings.     

Les pistes d’archosauriens : Kayentapus ubacensis nov. isp. (théropodes) et crocodylomorphes du Bathonien des Grands-Causses (France). Conséquences paléo-biologiques,environnementales et géographiques

Two tracksites yielding tridactyl footprints II-IV of theropods as well as supposedly sauropod tracks from the Causses Basin, briefly described in 2006 are reinvestigated. They are the Capelan tracksite (Meyrueis, Lozère) and the Garène tracksite (La Roque-Sainte-Marguerite, Aveyron), both Bathonian in age. In 2012, one of them (Le Capelan) was excavated and enlarged, allowing the discovery of numerous new tracks. In the Capelan tracksite, 102 concave epireliefs, 11 to 36 cm long, represent at least 21 trackways; the longest being visible along 37 meters. Footprints are almost as long as wide and show a large divarication angle II-IV (up to 70°). The largest of them (more than 24 cm long) were statistically compared with different Middle and Upper Jurassic ichnotaxa for which a synthesis is proposed. Tracks from the Causses Basin as well as those from the Capelan and the Garène tracksites can be ascribed to the ichnogenus Kayentapus. We propose a new ichnospecies K. ubacensis nov. isp. Whose trackmakers were tetanurian theropods, probably megalosaurids. At the Capelan, some marks are tentatively interpreted as swim tracks of crocodylomorphs. The supposedly sauropod tracks are here reinterpreted and considered as erosion cups and as concavities indicating the location of tree trunks. The sedimentological analysis indicates a paralic environment including lagoons and freshwater to brackish bays. They were separated from dysoxic lagoons by calcarenitic coastal barrier spits, and by tidal flats where microbial mats contributed to the good preservation of trackways. Despite the presence of “mangroves”, the main track-bearing surface from the Capelan was quite open and visited by megalosaurid dinosaurs of various sizes, moving in all directions but preferably to the North. The regional palaeogeography of the early-middle Bathonian is in accordance with a coastal area with low relief, bordering the “Seuil Cévenol”, which was probably emerged.     

Dinosaur footprints from the Early Jurassic of Le Mazel (Lozère,Southern France)

During the 20^th century, the first dinosaur tracks of the Causses Basin were identified at Saint-Laurent-de-Trèves, in the Parc National des Cévennes (southern France). A recent excavation reveals a new theropod tracksite in the Hettangian deposits from Le Mazel, 2 km from the historical tracksite at Saint-Laurent-de-Trèves. The tracks are here described combining a biometric approach and 3D imaging photogrammetry. The main track-bearing surface bears 64 in situ tridactyl footprints preserved as concave epireliefs. Two morphotypes were identified, a “Grallatorid” morphotype and a “Kayentapus” morphotype. Footprints belonging to the first morphotype are closely similar to Grallator lescurei, Grallator minusculus, and Grallator sauclierensis. This study shows the difficulty to distinguish quite similar tridactyl tracks from an ichnotaxonomic point of view and highlights the importance of detailed biometric comparisons. Tracks are preserved in a brown to yellowish dolomudstone showing abundant cryptalgal laminites and mud cracks. These deposits were accrued in shallow environments such as intertidal and supratidal zones of a tidal flat.     

Recommendation for the minimum number of steps to analyze when performing the uncontrolled manifold analysis on walking data

The uncontrolled manifold (UCM) analysis quantifies the extent to which co-variation among a set of variables facilitates consistent performance by partitioning variance in those variables into two components then calculating their normalized difference (i.e., the synergy index). Although UCM-derived measures are thought to depend on the number of data points analyzed, the minimum number needed to reasonably approximate true values of these measures is unknown. For each of two performance variables related to mechanical stability of gait, we evaluated changes in UCM-derived measures when increasing the number of analyzed points, here steps. Fourteen older adults walked on a treadmill while motion capture tracked movement. For each subject, n steps (where n = 2–99) were randomly sampled from the first 100, then used to calculate UCM-derived variables. For each subject, variables were expressed as a percent of the subject-specific value with n = 100 and averaged across 50 simulations. For each n, 95% confidence intervals (CIs) were calculated from group data. The minimum number of steps to “reasonably approximate” a variables was defined as the value of n for which the lower CI was >90% of the value with n = 100. Regardless of performance variable, reasonable approximations of the synergy index were attained with n = 16 steps, whereas n = 50 steps were needed for each of the variance components However, the differences between using 16 steps and 50 steps were small. Collecting 15–20 steps is recommended for a reasonable approximation of the synergy indices considered herein, particularly when data collection is constrained to a limited number of steps.     

Sidedness of membrane structures in Rhodopseudomonas sphaeroides. Electrochemical titration of the spectrum changes of carotenoid in spheroplasts,spheroplast membrane vesicles and chromatophores

The shift of the carotenoid absorption spectrum induced by illumination and valinomycin-K⁺ addition was investigated in membrane structures with different characteristics and opposite sidednesses isolated from Rhodopseudomonas sphaeroides. Right-side-out membrane structures were prepared by isotonic lysozyme-EDTA treatment of the cells (spheroplasts) and by hypotonic treatment of spheroplasts (spheroplast membrane vesicles). Inside-out membrane structures (“chromatophores”) were obtained by treating spheroplast membrane vesicles by French press or sonication.The membrane structures with either sidedness showed the same light-induced change of the “red shift” type. However, the absorbance change by K⁺ addition in the presence of valinomycin in the right-side-out membrane structures were opposite to that in the inverted vesicles, “blue shift” in the former and “red shift” in the latter. The carotenoid absorbance change was linear to membrane potential, calculated from the concentration of KCl added, with a reference on the cytoplasmic side, through positive and negative ranges.     

Phenolic metabolites of Ceratocystis ulmi

The C₁₀ acid 2,4-dihydroxy-6-(1-hydroxyacetonyl) benzoic acid, together with the 6-acetonyl- and 6-pyruvyl-analogues, has been identified as a metabolic product of Ceratocystis ulmi, the causative agent of Dutch elm disease. In a comparison of aggressive “fluffy” and non-aggressive “waxy” strains of C. ulmi, the C₁₀ acids were produced more rapidly and in greater yield by the former group.     

An improved method for preparing rat small intestine microsomal fractions for studying drug metabolism.

Epithelial cells from isolated rat small intestine were harvested by vibration of the everted intestine in 0.14 m NaCl containing 5 mm EDTA. These cells, which were largely free of mucus contamination, were homogenized in hypotonic (74 mm) sucrose using a Potter-Elvehjem homogeniser. After successively sedimenting a “brush border plus nuclei” and a “mitochondrial” fraction, microsomes were prepared from the postmitochondrial supernatant by ultracentrifugation or by precipitation at pH 5.0. The isolation and fractionation procedure was validated by the distribution of marker enzymes and by light microscopy and found to be largely uncontaminated by other subcellular components or by haemoglobin. The usefulness of this preparation was demonstrated by determining drug-metabolising enzyme activity and by substrate- and metabolite-binding spectra to cytochrome P-450. A comparison of precipitated “acid” and “normal” intestinal microsomes indicated similar apparent K_m and V_max values for a number of drug-metabolising enzymes. The content of components of the microsomal electron transport system were also similar in both preparations while the “acid” microsomes contained approximately 50% more protein.     

Pollenmorphology of Lysipomia H.B.K. and Rhizocephalum wedd. (Campanulaceae) and the revision of the pollen determination “Valeriana stenophylla” killip

Fossil pollen grains from the Quaternary of Colombia, formerly provisionally indicated as “Valeriana” stenophylla Killip, have now been identified as those of the Andean genus Lysipomia H.B.K. (Campanulaceae).In the genus Lysipomia s.l. (fide McVaugh) two considerably different pollen types are found: That of the Lysipomia s.s. and the Rhizocephalum type. The former was probably derived from the latter.     

Antigen recognition by T lymphocytes. 3. Evidence for two populations of thymus-dependent rosette-forming cells in spleen and lymph nodes

Rosette-forming cells, present in normal spleen, are composed of 70% theta-positive cells with “high” in vitro sensitivity to Azathioprine (AZ) (1 μg/ml) and 30% theta-negative cells with “low” sensitivity to AZ (500 μg/ml). Theta-positive RFC are also found in the thymus (with “high” sensitivity to AZ) and in lymph nodes and peripheral blood (with “intermediate” sensitivity to AZ:50 μg/ml). RFC with “high” sensitivity to AZ (T1) are eliminated from the spleen by adult thymectomy in less than 6 days; it takes more than 48 hours exposure to antilymphocyte serum (ALS) in vivo to suppress them, whereas RFC with “intermediate” sensitivity to AZ (T2), present in lymph nodes and peripheral blood, disappear 6 hours after in vivo ALS treatment but not after adult thymectomy.     

The invisible copper of cytochrome c oxidase. pH and ATP dependence of its midpoint potential and its role in the oxygen reaction.

Formation of the CO compound has been studied in intact mitochondria, submitochondrial particles and isolated cytochrome oxidase. The reaction requires the prior reduction of both cytochrome a₃ and one other single-electron acceptor. It is inferred that the second acceptor is the “invisible” copper which is undetectable by both optical and spin resonance spectroscopy. The overall process can be viewed as two single electron steps plus a ligand binding reaction. At high concentrations of CO, when titrations are performed at oxidation-reduction potentials significantly above the midpoints of either cytochrome a₃ or “invisible” copper, appearance of the CO compound follows a strict n = 2 (2-electron) relationship. Its midpoint potential is also dependent on the prevailing concentration of CO and is increased by approx. 30 mV for each tenfold increase in the level of CO. At redox potentials approaching the midpoints of cytochrome a₃ or “invisible” copper, significant deviations from n = 2 behavior are apparent which are readily detectable experimentally using low CO concentrations.A mathematical analysis of this model is presented and the oxidation-reduction properties of the CO compound are utilized to determine the midpoint potential of the “invisible” copper. This value is estimated to be 340 ± 10 mV at pH 7.8, independent of pH and the prevailing $\text{sol}\text{[ATP]}\text{[ADP]}\text{× [}\text{P}{}_1\text{]}$ ratio.By analogy with the observations on CO binding, the primary intermediate in the oxidase reaction with oxygen is concluded to be a bridged a₃²⁺-O₂-Cu¹⁺ complex. The initial reduction of molecular oxygen can then proceed via a thermodynamically favorable two-electron step to form a bridged peroxide intermediate. Subsequent reduction to water may later occur by way of two single-electron steps or one two-electron step.     

Responses of small vertebrates to linear clearings in a South Australian woodland

This work assesses whether the width and “permanence” of linear clearings affects the distribution and movement patterns of small, terrestrial vertebrates in a native South Australian woodland. We examined the influence of narrow (1.5 and 4.2 m), non-permanent seismic exploration tracks; and wide (6–7 and 12–15 m), permanent fire tracks. There were 1,007 captures of 14 species (four amphibians, six reptiles, four mammals) from 18,000 trap days/nights across 15 sites. Total species richness was highest adjacent to 6–7 m wide permanent tracks (8.3) and lowest in areas without clearings (5.3). There was heterogeneity of captures between track types (p < 0.008), species (p < 0.001), and species by track type (p < 0.001). Antechinus flavipes was most abundant adjacent to both types of permanent tracks, probably as a result of increased habitat complexity at these sites. Twenty-four percent of movements by recaptured A. flavipes involved track crossings. Animals crossed all track types; nevertheless, individuals were more likely to be recaptured on the same side of a track. Individuals were less likely to cross permanent tracks (p = 0.025 for 6–7 m and p = 0.008 for 12 to 15-m-wide tracks), with females being particularly inhibited. Although 11 % of 56 recaptured Rattus spp. had crossed a track, no individuals crossed the 12 to 15-m permanent tracks. In the habitat type studied here, narrow seismic lines may have a slightly positive effect on some ground-dwelling vertebrates, and do not appear to substantially inhibit movement. However, there is a need to carefully manage permanent tracks, which could isolate faunal populations.     

Differences in chromatin proteins of resting and growing human lymphocytes.

Two-dimensional polyacrylamide gel electrophoresis comparisons were made for the non-histone “Chromatin fraction II” proteins of normal, phytohemagglutinin-stimulated and acute leukemic lymphocytes. The “Chromatin fraction II” proteins were extracted from the nuclear residue fraction after initial treatment with (a) 0.075 M NaCl containing 0.025 M EDTA, pH 8; (b) 0.01 M Tris-HCl, pH 8; and (c) 0.4 N H₂SO₄. Most of the proteins found earlier in the “Chromatin fraction II” of rodent liver and hepatomas were also found in the human cells. Some changes such as the decrease in amount of protein BA of normal rodent cells were found in the comparison of normal and stimulated human cells. By comparison with normal lymphocytes, the phytohemagglutinin-treated cells had decreased spot densities and sizes for proteins BA and Bv and an increase in densities and sizes of proteins CB, C25, CS and CT. In the acute lymphocytic leukemic cells there was a decrease in spots A24, BA, Bv, CD and CD′ by comparison with the normal lymphocytes. Protein CG′ which was found earlier in the hepatomas was found in acute lymphocytic leukemic cells but not in the control or phytohemagglutinin-treated cells. These studies show that there is a loss in specific Chromatin proteins BA and Bv from the Chromatin of rapidly turning over cells. Concomitantly, increases are observed for the amounts of protein spots CB, C25, CS and CT in the actively growing cell samples.     

Modelling the vasculature of the stem of <Emphasis Type="Italic">Cyperus involucratus</Emphasis> Rottb.: evidence for three patterns of vascular bundles

Main conclusion

Three independent patterns of vein formation in Cyperus involucratus Rottb. were identified based on rare spontaneous interruptions of scape vein development. A number of developmental anomalies of vascular bundles in Cyperus involucratus Rottb. were identified and they include “turnabout”, “absent”, “twins”, “doublet”, amphivasal and various stages of “arrested”. These were used to develop a computer program to explain the three vasculature patterns of the scape of (a) ordered deployment of vascular bundles, (b) arrangement of tissues within vascular bundles and (c) orientation of vascular bundles with respect to stem edge. The computer model is a cell-by-cell determination of cell types and facet states.

     

Karyotypic instability of endoprophase and mitotic cells of Amoeba sp. strain Cont from the “proteus-type” group (Amoebozoa,Euamoebida, Amoebidae)

We performed karyotyping of Amoeba sp. strain Cont. Based on the results of a cytological analysis, we concluded that the chromosome number of Amoeba sp. strain Cont in mitosis was unstable. In all cases they appeared to be hypergaploid (the basic chromosome number is 30), with monosomy of all chromosomes except four shortest ones. The presence of “extrachromosomes” in the nucleus could prolong until the beginning of the anaphase. It was only then that they were ejected from the nucleus and the euploidy (haploidy) was restored. The stage of endoprophase nucleus was revealed in the cell cycle of Amoeba sp. strain Cont. This stage has not yet been found in other amoebae from the “proteus-type” group that had been previously studied (A. proteus strain B and A. borokensis). The maximum number of endoreplication rounds in the strain Cont amoebae nuclear cycle was 4 or 5. The regular extrusion of chromosomes from the nucleus into the cytoplasm occurred in each of the endoreplication rounds. Comparative cytological analysis of A. proteus strain B, A. borokensis and Amoeba sp. strain Cont karyotypes indicated that strain Cont, though rather close to the former two amoebae, is actually a distinct species.     

Light-break experiments and photoperiodic time measurement in the spider mite Tetranychus urticae

To explain photoperiodic induction of diapause in the spider mite Tetranychus urticae (Acarina: Tetranychidae) a theoretical model was developed, consisting of two components, viz. a “clock” and a photoperiodic “counter” mechanism. The clock executes photoperiodic time measurement according to hourglass kinetics; the counter accumulates the photoperiodic information contained in a number of successive $\text{light}\text{dark}$ cycles by adding up the number of “long” and “short” nights experienced by the developmental stages of the mites sensitive to the photoperiod. The influence of the circadian system on photoperiodic induction is interpreted as an inhibitory effect exerted on the expression of the photoperiodic response; this effect is encountered only in certain photoperiodic regimes, where the circadian system and the photoperiod are out of “resonance” with each other. This “hourglass timer oscillator counter model”, devised to give a theoretical explanation of photoperiodic time measurement, the summation of photoperiodic information, and the influence of the circadian system on photoperiodic induction, proved to be consistent with experimental results obtained with T. urticae in both symmetrical and asymmetrical “skeleton” photoperiods, the latter based on diel as well as non-diel $\text{light}\text{dark}$ cycles.     

Late devonian facies inter-relationships in bordering areas of the North Atlantic and their palaeogeographic implications

Late Devonian faunal and facies relationships are examined in seven around the North Atlantic — in eastern North America, Greenland, western Europe and northwest Africa. A shallow marine (“littoral”) environment, characterized by the genus Cyrtospirifer, is distinguished from a deeper water (“bathyal”) goniatite-conodont milieu on the one hand, and from the “Old Red Sandstone” terrestial facies bearing plant an d fresh-water fish remains on the other.Current or source directions indicate that an “Acadian Divide” existed, separating west-flowing drainage systems in North America from those flowing to the east on the Afro-European side. All species of the osteolepid Latvius, and the majority of species of Glyptopomus are found on the eastern flank. Conversely, the earliest amphibian, Ichthyostega, may have been confined to the western side of the divide.Palaeogeographic reconstruction places northwest Africa fairly close to the Catskill Delta in the Late Devonian, thus accounting for the presence of an “American fauna” in the former. North—south migration of littoral faunas along the Afro-European shores was, however, apparently inhibited.     

Letter: Notes on "heat loss from a Newtonian animal"

Parker, Baker &; Smith (1972) have demonstrated mathematically that given the evolution of sexual reproduction, disruptive selection for the production of either many small gametes or a few large gametes may occur, resulting in a stable polymorphism of “sperm” and “egg” producers. Their model for the evolution of anisogamy requires only that zygote fitness (F) increase steeply with increases in zygote volume (V) (for Foc∝ V^x, x must be greater than 1·5) and that a sufficiently broad range of zygote productivity-size variants exist in the population (the higher the value of x, the broader the range needed). They suggest that anisogamy is almost universal in multicellular organisms but relatively rare in unicellular organisms because only for the former is an investment in extra gametic reserves at the expense of the number of gametes produced likely to be worthwhile in terms of increasing the survival probability of the zygote. In this note a graphical analysis and evidence from the anisogamous Protista will be presented concerning this hypothesis.