Biometrical variability of foliage and cone characters inCupressus bakeri (Cupressaceae)

Biometrical variability of foliage, cones, and seeds were analyzed in 8 native populations (throughout the range) of a relictual species,Cupressus bakeri Jeps. (Cupressaceae) from California and Oregon. The partition of variation within and among populations for this rare plant was investigated and the justification for subspecies status was reviewed. Morphological characters varied significantly, with more of the variation among populations than at the population level. Multivariate analyses indicated close affinities among populations on serpentine sites suggesting the presence of a serpentine race. However, the high degree of variation among populations did not permit their clear separation into the two subspecies described byWolf (1948). We conclude thatC. bakeri should be treated as a monotypic species.     

Degradation artefacts during sample preparation for sodium dodecyl sulphate polyacrylamide gel electrophoresis

Preparation of samples for sodium dodecyl sulphate polyacrylamide gel electrophoresis routinely involves heating the protein in solution containing detergent and reducing agent for at least two minutes. Here we show that this treatment causes fragmentation of the protein glycogen phosphorylase, whether purified or as a component of a skeletal muscle preparation. The fragments are detected as minor bands on western blots and represent the products of discrete breakage point in the peptide sequence. Protease inhibitors cannot suppress the fragmentation.Such small amounts of immunoreactive fragments may be incorrectly identified on western blots as contaminants that were originally present in the antigen preparation. They may also be a source of ambiguity in studies that search for degradation intermediates during proteolysis.     

Reconciliation and Consolation in Captive Western Gorillas

We studied post-aggression mechanisms in a captive group of western gorillas (Apenheul Primate Park, The Netherlands) and compared them with those of wild mountain gorillas (Gorilla beringei). We found the same trend for reconciliation that wild mountain gorillas show: reconciliation occurred only between adult male-female dyads, while it was absent in the other sex-age class combination. There were both solicited and nonsolicited contacts; the latter finding is in contrast with the result obtained in wild mountain gorillas, in which consolation was absent. Immature females were more likely to offer consolation toward both related and unrelated individuals. Consolation did not reduce the likelihood of further attacks among group members. It may be that, as the α-male plays a fundamental role in preventing the spread of conflicts throughout the entire group, triadic contacts become ineffective for the function. The levels of consolation were higher in absence of reconciliation than in its presence, suggesting that consolation may function as an alternative mechanism in stress reduction of the victim.     

AGE-LENGTH RELATIONSHIPS IN HUMPBACK WHALES: A COMPARISON OF STRANDINGS IN THE WESTERN NORTH ATLANTIC WITH COMMERCIAL CATCHES

Strandings of previously identified individuals, while rare, provide an opportunity to examine age-length relationships in humpback whales (Megaptera novacangliae) from the North Atlantic. Ages and lengths of 23 individuals are presented: 11 females and 12 males, 9 of known age and 14 with estimated minimum ages. Lengths ranged from 853 to 1, 430 cm, ages 0.5–17 yr. These individuals were generally smaller and more variable in size at age than reported from commercial catches. Fifteen of the stranded individuals were four years of age or younger, while few of the animals taken by whalers were this young, and these probably represented the larger individuals in these age categories. Thus the data presented herein help to give more definition to the early growth curve for the humpback whale than has previously been available. Growth equations illustrate a difference of about one meter in asymptotic length through age five between stranding and catch data. The close fit of growth models to data from younger and older animals separately and the difficulty of fitting a single growth model to animals of all ages, could indicate that a dynamic or staged growth pattern exists in this species.     

Use of DNA-specific anthraquinone dyes to directly reveal cytoplasmic and nuclear boundaries in live and fixed cells

Image-based, high-content screening assays demand solutions for image segmentation and cellular compartment encoding to track critical events — for example those reported by GFP fusions within mitosis, signalling pathways and protein translocations. To meet this need, a series of nuclear/cytoplasmic discriminating probes have been developed: DRAQ5™ and CyTRAK Orange™. These are spectrally compatible with GFP reporters offering new solutions in imaging and cytometry. At their most fundamental they provide a convenient fluorescent emission signature which is spectrally separated from the commonly used reporter proteins (e.g. eGFP, YFP, mRFP) and fluorescent tags such as Alexafluor 488, fluorescein and Cy2. Additionally, they do not excite in the UV and thus avoid the complications of compound UV-autofluorescence in drug discovery whilst limiting the impact of background sample autofluorescence. They provide a convenient means of stoichiometrically labelling cell nuclei in live cells without the aid of DMSO and can equally be used for fixed cells. Further developments have permitted the simultaneous and differential labelling of both nuclear and cytoplasmic compartments in live and fixed cells to clearly render the precise location of cell boundaries which may be beneficial for quantitative expression measurements, cell-cell interactions and most recently compound in vitro toxicology testing.     

Census of gorillas in northern Republic of Congo

We censused gorilla populations in northern Congo from February to April 1989 and June 1990. The objective was to provide the first quantitative data from a variety of sites on gorilla populations from a country that had unknown but potentially high populations. The method used was a census of nests along strip transects. A total of 401.0 km of transects was sampled in four different study areas. The overall density calculated for all transects was 0.4 nesting gorillas/km². The highest density, 1.2 nesting gorillas/km², was found in the vast Likouala swamp area of north central Congo. The two northern sites showed low densities of 0.1 and 0.2 nesting gorillas/km², respectively. The northwestern site showed an intermediate density of 0.6 nesting gorillas/km². The vegetation type with the highest density was swamp forest with 2.4 nesting gorillas/km². The limited sample presented shows that gorillas are widespread and common in northern Congo, even in the swamp forests previously considered unsuitable as gorilla habitat. It is probable that Congo holds the largest population of gorillas in Africa after Gabon. © 1992 Wiley-Liss, Inc.     

Inhibition of Pair Formation by Concanavalin A and Concanavalin A-Binding Glycoconjugates in Euplotes octocarinatus

ABSTRACT. Concanavalin A (≥ 50 μg/ml) inhibits pair formation in both of the two complementary mating types of Euplotes octocarinatus studied in this investigation. This effect can be reversed by methyl-α- d -mannose. Concanavalin A is accessible for methyl-α- d -mannose until pairs are formed. Methyl-α- d -mannose as well as methyl-α- d -glucose and 2-acetamido-2-deoxy- d -glucose alone do not inhibit pair formation unless applied in concentrations ≥ 60 mM. The Concanavalin A-sensitive phase of preconjugant interaction starts 2 h after cells are induced to conjugate. Based on these observations we suggest that Concanavalin A might exhibit its action by binding to carbohydrate moieties of preconjugation-specific adhesion molecules and thereby might allosterically block interactions with their counterparts. To identify preconjugation-specific alterations in number or localization of Concanavalin A-binding glycoconjugates, we probed western blots of total cell proteins or fixed cells, respectively, with digoxigenin-labeled Concanavalin A. On Concanavalin A blots 20 different Concanavalin A-binding glycoconjugates were identified in mating-competent cells. Localization of Concanavalin A-binding sites on mating-competent cells by light microscopy resulted in predominant labeling of a comma-shaped structure near the paroral membranelle. During the preconjugation period no changes in number or localization of Con A-binding glycoconjugates were detected. Possible reasons are discussed.