Flagellar Adherence of Crithidia fasciculata Cells in Culture1

In early log phase cultures of several of the drug-resistant mutants of Crithidia fasciculata that we have previously obtained, a high percentage of cells attach in pairs at the base of the flagellum. This process, which we have termed “flagellar adherence,” lasts for several hours in some cases and occasionally involves changes in cell morphology. The attachment occurs optimally in gently agitated cultures. Flagellar adherent pairs can be disassociated by vigorous agitation; the pairs reappear in the culture within one to three h after disassociation. These paired forms can be clearly distinguished from the normal cell division forms. Clones of flagellar adherent-competent mutant strains are uniformly able to form these pairs in culture. A low percentage of flagellar adherent forms can be induced in wild type cells by glucose starvation.     

Flight behaviour of seabirds in relation to wind direction and wing morphology

We studied flight direction relative to wind direction (hereafter referred to as "flight direction"), the relation between wing morphology and flight behaviour and interspecies relationships in flight behaviour among all major seabird taxa. We calculated wing loading and aspect ratios for 98 species from 1029 specimens. Species were sorted into 13 groups on the basis of similarity in patterns of flight direction. The primary flight direction of Pelecaniformes and Charadriiformes was into and across headwinds. The most common flight direction of Procellariiformes was across wind. Seabirds avoided flying with tailwinds. Wing loading and aspect ratios were positively correlated in Procellariiformes, Pelecaniformes and alcids but negatively correlated in larids. In Procellariiformes, incidence of headwind flight and that of tailwind flight were significantly correlated with wing loading and aspect ratio; species with higher wing loading and aspect ratios flew more often into headwinds and less often with tailwinds. In contrast, the proportion of Pelecaniformes and Charadriiformes flying with tailwinds increased significantly with increased wing loading. Our results demonstrate a close link in seabirds between flight behaviour, wing morphology and natural history patterns in terms of distribution, colony location, dispersal and foraging behaviour.     

Terbutol Affects Spindle Microtubule Organizing Centres

Light, immunofluorescence, and electron microscopy were utilizedto investigate the effects of the herbicide terbutol (2,6-di-tert-butyl-p-tolylmethylcarbamate) on onion root tips. So-called ‘star anaphases,’chromosomes drawn in at their centromeres at both poles, resultingin a starburst of chromosomes were the predominant form of mitoticabnormality noted in root tip squashes of the terbutol-treatedroots. Immunofluorescence microscopy using antitubulin serareveals a cluster of microtubules radiating from the centreof the chromosome mass at each of the poles. Nuclear envelopesapparently reform around the radially-arranged chromosome masses,resulting in extensively lobed ‘star telophase’nuclei. Branched and curved phragmoplast arrays are observed,due to interference by the lobes of the star telophase nucleus.These abnormal phragmoplasts result in incomplete and/or abnormally-orientedcell walls. Star anaphase figures are observed after 2 h ofherbicide treatment, indicating that this terbutolinduced chromosomalabnormality is a primary effect of the herbicide. Tradescantiastamen hairs were treated with terbutol and mitosis was monitoredin vivo by Nomarski differential interference microscopy; thesetreated stamen hairs produce star anaphase figures as a primaryeffect of the herbicide. This series of abnormalities has notbeen observed with any other herbicide, indicating that terbutolhas a unique mechanism of action, perhaps interacting with spindlemicrotubule organizing centres. Key words: Terbutol, Onion, root tips, star-anaphase figures     

Biology of the ectomycorrhizal fungal genus, Rhizopogon

The morphology and anatomy of ectomycorrhizas of Rhizopogon arctostaphyli , R. ellenae , R. flavofibrillosus , R. occidentalis , R. rubescens , R. smithii , R. subcaerulescens and R. truncatus synthesized on Ponderosa pine ( Pinus ponderosa ) in glasshouse conditions using spore slurries, are described and compared. All species produced a well-developed Hartig net, and a well-developed fungal mantle. The mantles of R. arctostaphyli , R. smithii and R. subcaerulescens ectomycorrhizas were two-layered with outer mantle hyphae of wider diameter than inner mantle hyphae. The mantle of R. subcaerulescens ectomycorrhizas also had distinctive peg-like structures (cystidia) along peripheral hyphae. Rhizopogon truncatus ectomycorrhizas were tuberculate in morphology and had a rind-like mantle enclosing adjacent roots. In addition, several species exhibited crystal inclusions in the outer mantle, presumably at the interface between mantle and soil.     

Oscillations in the Activities of Enzymes of Nitrate Reduction and Ammonia Assimilation in Glycine max and Zea mays

The activities of glutamate dehydrogenase (GDH), glutamine synthetase (GS), and nitrate reductase (NR) and the levels of soluble protein and NO^-₃ were assayed in soybean (Glycine max [L.] Merr.) leaves over a 48-h period with the initial 24 h under a light-dark cycle (LD 16:8) followed by 24 h of continuous light (LL). Plants had been entrained for 30 days under the LD regime. Maize (Zea mays) leaves (10 days old) under a LD 15:9 cycle were assayed only for NR and nitrite reductase (NiR). Data were subjected to frequency analysis by the least squares method to determine probabilities for cosine function periods (τ's) between 10 and 30 h. NR activities for both soybean and Zea leaves had 24 h τ's with P values < 0.05 indicating circadian periodicity. GDH in soybeans had a 24-h rhythm under LD conditions which lengthened under LL conditions. The 24-h rhythm of GDH displayed maximal activity toward the end of the dark period of the LD cycle whereas the highest activity of NR was early in the light period. Total soluble protein displayed a rhythm with a best fitting τ of greater than 24 h under both LD and LL. GDH, GS, NR, NO₃, and soluble protein in soybeans and NiR in Zea, all displayed that were ultradian (10–18 h), indicating that a τ of about one half a circadian periodicity may be a common characteristic of the enzymes of primary nitrogen metabolism in higher plants. These data also demonstrate that although both NR and GDH are circadian in their activity, the 24-h rhythm may be greatly influenced by ultradian oscillations in activity.     

Potential of high‐density pheromone‐releasing microtraps for control of codling moth Cydia pomonella and obliquebanded leafroller Choristoneura rosaceana

Recent large‐cage studies with codling moth Cydia pomonella (L.) reveal that the removal of moths from an apple orchard using pheromone‐releasing traps is more effective at reducing capture in a central monitoring trap than is a mating disruption protocol without kill/capture. The present study uses open orchard 0.2‐ha plots comparing a high‐density trapping scenario with mating disruption to confirm those results. Two tortricid moth pests of tree fruit are studied: codling moth and obliquebanded leafroller Choristoneura rosaceana (Harris). Codling moth treatments include Isomate CM FLEX (ShinEtsu Ltd, Japan), nonsticky traps baited with Trécé CM lures (Trécé, Inc., Adair, Oklahoma), and sticky traps baited with Trécé CM lures, all at equal application rates of 500 dispensers ha^?1, as well as a no pheromone control. These microtraps are of a novel design, small and easy to apply, and potentially inexpensive to produce. Mating disruption using Isomate CM FLEX and nonsticky traps reduces codling moth capture in standard monitoring traps by 58% and 71%, respectively. The attract‐and‐remove treatment with sticky traps reduces capture by 92%. Obliquebanded leafroller treatments include Isomate OBLR/PLR Plus and Pherocon IIB microtraps baited with Trécé OBLR lures, both applied at 500 dispensers ha^?1, as well as a no pheromone control. Mating disruption reduces capture in monitoring traps by 69%. The attract‐and‐remove treatment reduces capture by 85%. Both studies suggest that an attract‐and‐remove approach has the potential to provide superior control of moth populations compared with that achieved by mating disruption operating by competitive attraction.     

Temperature as an Ecological Resource

Ectothermic vertebrates respond to the temperature of theirhabitat in a manner that is remarkably similar to their responseto more traditional ecological resources such as food. We reviewthe response to temperature primarily from literature on fishesin terms of ecological concepts related to niche theory andcompetition. The width of the fundamental thermal niche is about4°C when measured by a mean plus and minus one standarddeviation of the distribution of temperature occupied in a laboratorygradient. Fish of temperate freshwater appear to fall into threethermal guilds along the temperature resource axis —cold,cool, and warm water fishes. Realized thermal niches are similarin central tendency to fundamental niches, but niche width appearsto be more narrow for the realized niche in limited sample data.The success of interference competition for space with preferredtemperature is tied to social dominance in a manner analogousto food competition. Thermal niche shifts in the face of interspecificcompetition for preferred temperature appear supported by onelaboratory study. Exploitation competition in respect to temperatureseems nebulous. If animals successfully compete for their thermalniche, growth and perhaps other measures of fitness are maximized.Cost/benefit models for thermal resources and food resourceslead to similar predictions about resource use. We suggest thatviewing temperature and other niche axes in the way ecologistshave viewed food resources would be useful.     

Causes of variation in wing loading among Drosophila species

We examined influences on wing and body size in 11 species (12 strains) of Drosophila. Six measures of wing length and width were closely correlated with wing area and suggested little variation in wing shape among the species. Among ten species wing loading, an important factor in flight costs and manoeuvrability, increased as body mass increased at a rate consistent with expectations from allometric scaling of wing area and body mass to body length. Intraspecific variation in wing loading showed similar relationships to body mass. Density and temperature during larval development influenced wing loading through general allometric relations of body size and wing area. Temperature during the pupal stage, but not during wing hardening after eclosion, influenced wing area independently of body size. Wing area increased as growth temperature decreased. Individuals reared at cooler temperatures thus compensated for a potential allometric increase in wing loading by differentially enlarging the wing area during pupal development.     

Ecteinascidia turbinata Extract Activates Components of Inflammatory Responses Throughout the Phylogenetic Spectrum

The tunicate Ecteinascidia turbinata contains a substance orsubstances capable of exerting a number of biological effects.Extracts of tunicate tissues have been shown to kill tumorcells in vitro and arrest tumor growth in vivo. The extractsalso suppress allograft rejection, graft-US.-host reactionsand lymphocyte proliferative responses as well as humoral responsesto immunization. By modifying the conditions, the extracts couldpotentiate antibody responses. In addition, they augment functionsof monocyte-macrophages as evidenced by in vitro phagocytosis,in vivo clearance, and cytotoxic activity against target cells.After studies in mice, we were able to demonstrate that theextracts could activate the phagocytic systems of shrimp, bluecrab, and fish (the American eel). In fish, the intraperitonealroute was superior to the intravenous route for promotion ofphagocytosis, increase in percent presentation of granulocytesand for enhancement of resistance to bacterial infection. Intrarriuscularand intraperitoneal injection led to local inflammation withaccumulation of granulocytes and macrophages.     

Aggressive Social Organization in Nectarivorous Birds

I argue that a net benefit model of aggressive social organizationis consonant with observed variation between territorial anddominance systems. For nectarivores net benefits are associatedwith obtaining nectar. Costs are time and energy associatedwith aggression and possible risks of injury. The fitness criterionprobably varies across situations and may be long or short-term.An important problem for behaviorists is to understand the positionin a time hierarchy at which particular social interactionsare important.