Action of Sorghum Proteinase on the Protein Bodies of Sorghum Starchy Endosperm

Protein bodies isolated from the starchy endosperm of ungerminatedsorghum exhibited some autolytic activity but seemed incapableof significant self-hydrolysis. Enzyme assay, transmission electronmicroscopy, sodium dodecyl sulphate—polyacrylamide gelelectrophoresis and amino acid analysis revealed that a proteinaseextract from germinated sorghum could degrade the protein bodiesin a manner resembling that which takes place in vivo. The proteinbodies were degraded mainly from the periphery. Glutelin (matrixprotein) was first hydrolysed, followed by the prolamin proteinbody protein. Proteinase extracts from both the germ and endospermof germinated sorghum were capable of degrading the proteinbodies. This finding is consistent with the concept that theproteinase is synthesized in the germ and then secreted intothe starchy endosperm during germination. Key words: Sorghum bicolor, protein body degradation, proteinase.     

Antimalarial Properties of Imipramine and Amitriptyline12

Dietary riboflavin deficiency is known to diminish malarial parasitemia. In this study, we determined whether imipramine and amitriptyline, drugs which inhibit riboflavin metabolism, have antimalarial efficacy. In addition, we evaluated whether these drugs, like other antimalarial agents, increase the hemolytic response to ferriprotoporphyrin IX (FP). The growth of Plasmodium falciparum (FCR3) in the absence and presence of these drugs (10 to 75 μM) was measured by determining (³H)hypoxanthine uptake by intraerythrocytic parasites for 48 h in RPMI 1640 medium. The uptake of (³H)hypoxanthine was significantly reduced in a dose-dependent manner by both imipramine and amitriptyline. The IC₅₀ values of imipramine and amitriptyline at 48 h were 56 and 45 μM, respectively. Both drugs enhanced hemolysis induced by FP (10 or 20 μM). No hemolysis by these drugs was detected in the absence of FP. It is concluded that the tricyclic antidepressants, imipramine and amitriptyline, possess substantial antimalarial properties.     

Identification of predominant environmental factors structuring stream macroinvertebrate communities within a large agricultural catchment

• 1 Patterns of macroinvertebrate community composition were examined in streams within a 40000-km² catchment in central Michigan, U.S.A., to identify the major environmental gradients influencing community variation. Agriculture and associated clay and sandy soils predominated in much of the region.
• 2 Eighty macroinvertebrate taxa were collected from stream surveys conducted during May and August 1990. Community composition varied primarily by the proportions of Plecoptera and Ephemeroptera. Benthic communities from the heaviest agricultural zones were most different from those at other sites.
• 3 Chemical composition among the sites varied most in relation to nutrients (NH₃, NO3, PO₄). Other parameters were relatively similar. Physical characteristics of the sites were scored in six habitat categories: (i) substrate characteristics, (ii) instream cover, (iii) channel morphology, (iv) riparian zone and stream-bank conditions, (v) riffle/run quality, (vi) pool quality. Most physical habitat scores were lowest in the intense agriculture zones.
• 4 The relative importance of physical and chemical variables in explaining variation in macroinvertebrate communities was quantified using canonical correspondence analysis. Substrate characteristics were most important in both surveys. Significant correlations (P<0.05 and P<0.10) were observed between substrate quality and total numbers of Ephemeropteran, Plecopteran, and Trichopteran taxa. These relationships reflected correlations from sites in the clay soil-type region (P<0.01 and P<0.10) which contrasted with non-significant results from the less impacted, sandy soil-type region.
• 5 Effective stream restoration efforts in this region will require the alteration of local land-use activities that influence the physical habitat. Further development of empirical relationships between catchment activities and substrate and channel characteristics within natural geomorphic regions is essential for the evaluation of restoration projects.

     

Seasonal variation in vertical and horizontal movement of the freshwater bivalve Elliptio complanata (Mollusca: Unionidae)

1. Vertical and horizontal movement were studied in the freshwater bivalve Elliptio complanata at a sandy site in an oligotrophic lake over 3 years. Mussel movement did not vary significantly between day and night. On average, between 2 and 8% of 527 mussels moved each month during the ice-free season and the distance travelled by moving mussels averaged 0.6 cm day^–1.
2. Mussels were endobenthic during the winter, emerged from the sandy substrate in mid-May, peaked in sediment surface abundance in July, and descended into the sediments for the winter in September–October. Vertical displacement of mussels was closely correlated with water temperature although daylength may play a role. Mussels apparently move very little beneath the sediment during the winter.
3. The number of mussels moving horizontally at any given time was linearly correlated with daylength, but the distance travelled during a sampling period was related to daylength in a non-linear fashion. Greatest horizontal displacement of epibenthic mussels was found during spring and early summer, coincident with spawning in E. complanata     

Ionic Permeability of Insect Epithelia

In general, ionic regulation will depend on active transportby epithelia and also on the permeability properties of thesetissues. Passive permeability has recently been studied in thehindgut of the desert locust Schistocerca gregaria using electrophysiologicaland radiotracer techniques. Although locust rectum has low electricalresistance, cell membranes provide the major route for transepithelialionic diffusion; i.e., the locust rectum is a tight epithelium.Potassium permeability (P_K) is apparently regulated by luminalK and osmotic concentrations (local control), and also by thepeptide hormone CTSH (chloride transport-stimulating hormone).Transepithelial resistance declines when isolated recta areexposed to CTSH or its "second-messenger" cAMP (adenosine 3':5'-cyclicmonophosphate). Cyclic-AMP also stimulates K diffusion acrossrecta by 400%. Intracellular cable analysis indicatesthat cAMPlowers apical and basal membrane resistances (R_a and R_b, respectively)by {small tilde}80%; however different ionic permeabilitiesare affected at thelumen- and hemolymph-facing membranes: ThecAMP-induced decline in R_a, requires potassium whereas R_b isCl-dependent. The actions of cAMP on active transport and passivepermeability are complementary and would allow remarkably efficientcontrol over KC1 absorption in vivo. One hypothesis is as follows:CTSH elevates intracellular cAMP concentration by stimulatingadenyl cyclase. Cyclic-AMP enhances transepithelial Cl absorptionby stimulating a Cl pump in the apical membrane and also byincreasing the Cl permeability of the basal membrane. PassiveK absorption would also increase during cAMP stimulation sinceCl transport results in a more positive luminal potential, andbecause cAMP elevates transrectal P_K. The mechanisms by whichmembrane permeability is regulated in insects have not yet beenstudied, but these might involve the modulation of ion channelsby cAMP- or calmodulin-dependent phosphorylation, Ca or calmodulinbinding, methylation, or insertion of new channels into themembrane.     

Symbols of Substance: Bimin-Kuskusmin Models of Procreation,Death, and Personhood

The Bimin-Kuskusmin of the West Sepik interior of Papua New Guinea elaborate a complex folk theory of procreation that becomes the ‘natural’ foundation of some ideologically significant constructions of the individual, the person, gender, and societal continuity. Drawing on certain aspects of Weiner's model of reproduction and regeneration, symbols of substance and insubstantial ‘spirit’ that form this ‘natural’ foundation of the Bimin-Kuskusmin ideology of birth, death, and rebirth are explored in contexts of rites of passage that mark the course of the life-cycle from conception to death and ancestorhood. The key symbols of this cultural ideology are the enduring substances of bone, bone marrow, and finiik spirit, which are the basis of reckoning the cyclical regeneration of clan categories.     

Topography and tectonics of the Taconic outer trench slope as revealed through gradient analysis of fossil assemblages

Similarities in stratigraphic sequence, syndepositional topography and tectonics, and regional tectonic setting between the Mohawk Valley, New York, in the Middle Ordovician and the Australian flank of the Timor Trough today support the idea that the Taconic Foreland Basin orginated in an arc-continent collision. The Trenton Group strata studied - a roughly four million year long sequence correlated by bentonite beds along an 83 km downslope transect in the central Mohawk Valley - represent the continental shelf and outer trench slope. Bank limestones pass upward and downslope into deep water black shales in a manner reminiscent of the lateral and vertical sedimentary sequence on the Sahul Shelf and Australian flank of the Timor Trough. In studying topography, relative depth was measured through reciprocal averaging ordination of benthic macroinvertebrate fossil assemblages. Downslope bathymetric profiles show the development of a horst and graben topography coincident with regional tilting and transgression - a pattern associated with downward flexure of the Australian Plate approaching Timor. The net rate of transgression corresponds to an arc-continent convergence rate on the order of 2 cm per year.     

The Upper Triassic fishes from Polzberg bei Lunz, Austria

Carnian (Upper Triassic) fishes from Polzberg bei Lunz have been known since 1886 but no comprehensive account has been published. Eleven species are described nine of which, Saurichthys calcaratus, Polzbergia brochatus, Peltopleurus dirumptus, Habroichthys gregarius, Nannolepis elegans, Phaidrosoma lunzensis, Elpistoichthys pectinatus, E. striolatus and Pholidophoretes salvus are new, and two others, Thoracopterus niederristi Bronn and Gigantopterus telleri Abel, previously little-known.
New supraspecific taxa defined are:the order Polzbergiiformes, the family Thoracopteridae and the genera Polzbergia, Nannolepis, Phaidrosoma, Elpistoichthys and Pholidophoretes.
Habroichthys, Thoracopterus, Gigantopterus and Nannolepis show an unusual skull-roof pattern and are included in the re-defined order Luganoiiformes.
Two new ichthyokentemids considerably extend the known time-range of this family.
The genus Pholidophoretes is intermediate between the Archaeomenidae Goodrich 1909, and the Pholidophoridae sensu stricto Nybelin 1966.
The Polzberg assemblage was probably mainly marine with a small freshwater contribution; it shows less similarity to the Besano and Raibl assemblages than these do to each other.
The Luganoiiformes are probably, but not certainly, monophyletic; relationships within the order are analyzed and a cladogram constructed.
The Platysiagiformes, Peltopleuriformes, Luganoiiformes and Cephaloxeniformes could all have been derived from a common ancestor at the Perleidus level and are probably offshoots of the perleidid radiation.