African Buffalo Serum Contains Novel Trypanocidal Protein

ABSTRACT. The high ability of African buffalo, as compared to domestic cattle, to control infections with Trypanosoma brucei brucei IL Tat 1.4 organisms did not correlate with the timing or magnitude of parasite surface coat-specific antibody responses and may have resulted from the constitutive presence in buffalo blood of a novel trypanocidal factor. Buffalo plasma and serum contained material that killed bloodstream stage T. b. brucei, T. b. rhodesiense, T. b. gambiense, T. evansi, T. congolense , and T. vivax organisms during four h of incubation at 37° C in vitro. Serum from eland was also trypanocidal whereas serum from oryx, waterbuck, yellow-back duiker, cattle, horse, sheep, goat, mouse, rat, and rabbit was not trypanocidal. The buffalo serum trypanocidal material was not lipoprotein, or IgG, and had the following properties: 1) a density of < 1.24 g/ml determined by flotation ultracentrifugation; 2) insolubility in 50% saturated ammonium sulphate; 3) non-reactivity with anti-bovine IgM, and anti-bovine IgG; 4) non-reactivity with protein G, and protein A; 5) a relative molecular mass of 152 kDa determined by chromatography on Sephacryl S 300, and of 133 kDa determined by chromatography of the 50% SAS cut of IgG-depleted buffalo serum on Superose 12; 6) no associated cholesterol; and 7) inactivation by digestion with proteinase K that was immobilized on agarose.     

Differentiation in populations of Hordeum spontaneum Koch along a gradient of environmental productivity and predictability: plasticity in response to water and nutrient stress

Plants from four populations of Hordeum spontaneum originating in distinct environments of Israel were compared for stress induced phenotypic plasticity. The environments ranged along a gradient of increasing rainfall amount and predictability from low (desert) to moderate (semisteppe batha) to high (Mediterranean grassland and mountain, the latter also experiencing frost stress). The plants were exposed to a set of four treatments: no stress (optimum water and nutrients), water, nutrient and both water and nutrient stress. Plants from the four populations (or ecotypes) exhibited different patterns of plasticity in response to the different stresses (water and nutrients) and in different trait categories (reproductive, fitness and resource allocation). The importance of plasticity in response to water stress appears to decrease, and to nutrient stress appears to increase along the increasing rainfall gradient. The mountain ecotype, growing in an area with high potential productivity (amount of rainfall) but experiencing periodic frosts, was the most plastic among ecotypes in resource allocation under both water and nutrient stress, but exhibited low plasticity in other trait categories. In contrast, the desert ecotype had low plasticity in resource allocation under water stress and the lowest plasticity among the four ecotypes in all trait categories in response to nutrient stress. The ecotype originating in Mediterranean grassland, a predictable and most favourable environment, was highly plastic in fitness and allocation traits in response to low nutrient levels which is likely to occur due to competition in productive environment. We discuss the observed differences in ecotype plasticity as part of their environmentally induced adaptive ‘strategies’. We found no support for the hypothesis that plants originating in environments with greater variation and unpredictability are more plastic. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society 2002, 75 , 301–312.     

Polymerase Chain Reaction-Based Sex Identification in the Greater Roadrunner

Abstract: We determined a polymerase chain reaction (PCR)-based method to identify the sex of greater roadrunners (Geococcyx californianus). We found that previously reported primer combinations used in other bird species did not work reliably in roadrunners. However, a novel primer combination (P2-1237L) allowed for consistent and reliable sex identification of roadrunners. Conducting several PCR replicates per sample helped to identify occasional preferential amplification of the Z band that could occur in females (the heterogametic sex; i.e., WZ). Identifying the sex of individuals will allow for examination of sex-associated differences in home range size and habitat use, population demographics, and parenting behavior, as well as for a better understanding of the social system of roadrunners.     

IN VITRO BEHAVIOR OF GUINEA PIG ARTERIAL AND VENOUS ENDOTHELIAL CELLS *

Techniques to clone endothelial cells from adult guinea pig artery and vein are described. Cloned arterial and venous endothelial cells differed in their in vitro behavior. The differences between these two types of endothelial cells grown under identical conditions are: (1) venous endothelial cells have a greator mitotic potential than the arterial cells, (2) arterial endothelial cells have a much greator affinity to the substratum than venous endothelial cells, and (3) arterial endothelial cells exhibit a marked propensity to deposit lipid in their cytoplasm; whereas, the venous endothelial cells do not reveal lipid droplets. Labeled ³H-oleic acid added to the nutrient medium was incorporated into the lipid deposits found in the arterial endothelial cells. Both types of endothelial cells bound antibody prepared against smooth muscle myosin. The observed difference in the in vitro behavior of these two types of endothelial cells may be a reflection of their intrinsic characteristics.     

Management Implications of Cover Selection Data: Northern Bobwhite Example

Abstract: We derived a method of estimating the direction and magnitude of cover changes for potentially maximizing wildlife abundance on an area. We illustrate the method with data on cover selection by northern bobwhites (Colinus virginianus) collected in the Texas Panhandle from 2000 to 2003. We used radiotelemetry to determine use of cover associations, Geographic Information System analysis to determine their availability, and logic related to use-availability analysis to collapse 95% kernel home ranges to usable space. Bobwhites selected mixed-shrub cover consisting of sand plum (Prunus angustifolia) and fragrant sumac (Rhus aromatica), and they avoided or neutrally used 8 other cover associations. However, grass upland and sand sagebrush (Artemisia filifolia) associations occurred in ≥86% of home ranges (n = 96 bobwhites with ≥30 radiolocations). Usable space averaged 54.2% ± 1.72 SE of kernel home ranges. The data indicated that adding about 226 ha of mixed-shrub cover or a structural homologue while simultaneously reducing the quantity of most other cover associations would maximize bobwhite abundance. An area with 30–60% mixed-shrub cover, with the balance in grass upland and sand sagebrush, and with cover dispersed such that no point was >30 m from mixed-shrub cover was hypothetically optimal for bobwhites in our region. Within certain constraints (e.g., financial, social, edaphic), managers can apply this method by manipulating cover types through relevant management practices (e.g., planting, prescribed burning, mechanical removal of vegetation). This method, with minor modification, could also be used to decrease usable space on an area, and thus decrease wildlife densities, should that be the manager's objective.     

Webs of theridiid spiders: construction, structure and evolution

Understanding the web construction behaviour of theridiid (comb-footed) spiders is fundamental to formulating specific evolutionary hypotheses and predictions regarding the reduction of orb-webs. We describe for the first time in detail the web construction behaviour of Achaearanea tepidariorum , Latrodectus geometricus , Theridion sisyphium and T. varians as well as webs of a range of other theridiids. In our survey we distinguish four major web types. Among webs with gumfooted lines, we distinguish between webs with a central retreat ( Achaearanea -type) and those with a peripheral retreat ( Latrodectus -type). Among webs without gumfooted lines, we distinguish between those which contain viscid silk ( Theridion -type) and those with a sheet-like structure, which do not ( Coleosoma -type). Theridiid gumfoot-webs consist of frame lines that anchor them to surroundings and support threads which possess viscid silk. Building of gumfooted lines constitutes a unique stereotyped behaviour and is most probably homologous for Nesticidae and Theridiidae. Webs remained in place for extended periods and were expanded and repaired, but no regular pattern of replacement was observed. We suggest that the cost of producing and maintaining viscid silk might have led to web reduction, at least in theridiids.  © 2003 The Linnean Society of London. Biological Journal of the Linnean Society , 2003, 78 , 293−305.     

Strontium-substitution for Calcium and Algal Cell Size

Mature cells of several algal species (Protosiphon bo-tryoides, Chlorococcum echinozygotum, Asterococcus superbus, Chlamydomonas reinhardtii, Chlorella pyrenoidota) that will grow in a strontium-substitution for calcium are larger and more highly vacuolated than control cells in calcium. In logarithmic phase cultures average cell size of cells in strontium-replacement medium is greater than for control cells in calcium. The water content of strontium-replacement cells is indicated to be greater than of control cells. Mechanisms whereby water content and cell size differences may become established are discussed.     

Cell Junctions in Arthropod Ion-transport Systems

The epithelial cells involved in the movement of ions and waterform a major subset of all epithelial cell types. Both the formand the functions of cell junctions present in these cells areessentially the same as those found elsewhere. Gap junctionsare believed to regulate intercellular communication; desmosomesand hemidesmosomes provide mechanical anchorage to other cellsand the extracellular matrix; septate junctions play roles inproviding cell to cell anchorage, and perhaps in sealing thelateral surfaces of adjacent cells together to prevent paracellularfluid and solute movement; tight junctions (of limited distributionin insects) are seals between adjacent cells. They form a barrierto the paracellular movement of solutes and water. Examination of the junctions in salivary glands and midgut provideinsight into the roles of these junctions in the developmentand function of ion transport systems. In Manduca sexta (Johannsen)the cells of the salivary gland are joined by pleated septateand gap junctions. Individual salivary cells have numerous foldsand canaliculi. The walls of the canaliculi consist of extensivelyfolded plasma membrane in intimate association with mitochondria.Gap junctions connect adjacent parts of the same cell acrossmembrane folds, effectively shortening diffusion distances inthe cells. Hemidesmosomes are present in the walls of developingcanaliculi. They are attached to pore filaments that occupythe lumen of the developing canaliculi. The hemidesmosomes andpore filaments may have a morphogenetic role as they disappearafter the canaliculi are formed. In Manduca sexta the midgut cells are joined by gap and septatejunctions. These junctions differ in morphology from their counterpartsin the salivary gland; physiological studies show the gobletcells are not coupled to neighboring tall columnar cells. Wehave shown the gap junctions joining them are typical of non-couplingjunctions. Preliminary studies suggest that the gap junctionschange form when the cells are coupled.