In vitro oxygen consumption and motility of Cryptobia salmositica, Cryptobia bullocki, and Cryptobia catostomi (Sarcomastigophora: Kinetoplastida).

Cryptobia salmositica (pathogenic and vaccine strains), Cryptobia bullocki (pathogenic), and Cryptobia catostomi (nonpathogenic) have similar oxygen consumption rates (0.17 +/- 0.01 nm O2/10(6) parasites). Incubation with sodium azide (5 microliters of a 1-M solution to 1 ml of parasite suspension, i.e., a 5-mM final concentration) reduced the oxygen consumption by approximately 4.5-fold. Motility of the parasites was also greatly reduced in sodium azide. The oxygen consumption and motility of the parasites returned to preazide treatment levels when the azide was removed even after 24 hr of incubation in sodium azide. The activities of hexokinase, pyruvate kinase, and cytochrome C oxidase were not detected in the 3 species of Cryptobia.     

Isozymic pattern of lactate dehydrogenase in cases of bancroftian filariasis.

Isozymic patterns of lactate dehydrogenase (E.C. 1.1.1.27) by polyacrylamide gel electrophoresis (PAGE) were observed in various categories of filariasis and controls, i.e. asymptomatic microfilaraemia and symptomatic amicrofilaraemia, endemic normal and non-endemic normal. Lactate dehydrogenase (LDH) activity was also observed amongst the above categories of patients. An increase in enzyme activity and change in the isozymic pattern was observed in the above categories of filaria infected serum. LDH activity doubled in asymptomatic microfilaraemia whereas in symptomatic amicrofilaraemia the increase in LDH activity was thirtyfold. The isozymic pattern of microfilaraemic cases showed the presence of three bands B4, A1B3, A2B2, which are quite thick as compared to normal healthy subjects, whereas the patients with symptomatic amicrofilaraemia showed marked elevation of serum LDH-4 or A3B1. The LDH was partially purified by combined treatment of (NH4)2SO4 fractionation and gel filtration. The isozymic pattern of purified LDH showed a similar pattern.     

Inhibitory effects of endothelin-1 and endothelin-3 on prolactin release: possible involvement of endogenous endothelin isopeptides in the rat anterior pituitary.

Spontaneous prolactin release from the isolated rat anterior pituitary was inhibited by endothelin-1 in a dose-dependent manner (10(-8)-10(-6) M). Endothelin-3 also inhibited spontaneous prolactin release with an almost identical dose-response relationship as endothelin-1. These inhibitory effects were unaffected by application of a dopamine D2-receptor antagonist, YM-09151-2 (10(-7) M). Rat anterior and posterior pituitary glands were abundant in both endothelin-1 and endothelin-3, as compared with other regions of the brain. The present results suggest that endogenous endothelin-1 and endothelin-3 in the anterior and posterior pituitary are involved in the inhibitory regulation of prolactin secretion as autocrine or paracrine factors.     

Expression of the Saccharomyces cerevisiae Kex2p endoprotease in inset cells. Evidence for a carboxy-terminal autoprocessing event.

The pheromone-processing Kex2p endoprotease of Saccharomyces cerevisiae has been difficult to characterize due to its low level of expression in yeast cells. To overcome this problem, we have overexpressed Kex2p using the baculovirus/insect cell expression system. Spodoptera frugiperda Sf9 insect cells infected with a recombinant baculovirus, containing the complete KEX2 gene which encodes the Kex2p protease (814 amino acids), accumulate an 120-kDa functional form of the enzyme. The inhibition profile of the insect-cell-derived endoprotease is similar to that of the yeast enzyme. The recombinant infected insect cells also secrete into the medium about half of the total Kex2p activity produced. Deleting the carboxyl-terminal tail and the transmembrane domain of Kex2p (Kex2 delta p, 666 amino acids) does not measurably interfere with the enzyme characteristics and results in the secretion of up to 90% of the total enzyme activity. The truncated form, Kex2 delta p, of the endoprotease accumulates in the cell supernatant to 6.7 x 10(5) U/l. The molecular mass of the secreted forms for both the wild-type Kex2p and Kex2 delta p is the same (70 kDa) and is 50-kDa lower than the intracellular form. This result implicates a processing event which gives rise to shorter extracellular forms of both the wild-type Kex2p and Kex2 delta p and which trims their carboxy termini upsteam of amino acid 666. This processing event requires the integrity of the Ser385 of the Kex2p active site.     

The influence of religious affiliation on surname repetition in marriages in Tiszaszalka, Hungary.

The repeated-pairs of surnames in marriages (RP) approach is applied to the population of Tiszaszalka in north-eastern Hungary. The results indicate that: (1) lineage-like behaviour in mate choice results in population subdivision in both the Catholics and the Protestants of the village; (2) unlike in some other Tiszahat villages, the isonymous and the repeating unions in Tiszaszalka occur in different lineages so, in neither of these subpopulations are isonymous and repeating unions monopolised by a few lineages; (3) religious affilitation influences the mating structure of the population as measured by RP summary scores.     

Preparation and Optimization of a Cell-free Translation System from Vicia sativa Germ Lacking Ribosome-inactivating Protein Activity

A cell-free translation system from Vicia sativa with high activityfor reading endogenous messengers was prepared. The concentrationsof several of the components were optimized. The system washighly sensitive to cycloheximide, puromycin and fusidic acid,but was completely insensitive to chloramphenicol. The systemlacks apparent free endogenous ribosome-inactivating proteinactivity. It was highly sensitive to several well-known ribosome-inactivatingproteins, which makes it very suitable for studying the effectsand the mechanism of action of these plant toxins. Key words: Translation system, protein synthesis, cell-free extracts, ribosome-inactivating proteins, Vicia sativa     

PATTERNS IN LEAF MORPHOLOGY AND PHOTOSYNTHESIS IN SHOOTS OF SASSAFRAS ALBIDUM (LAURACEAE)

Trees of Sassafras albidum (Nuttall) Nees. display leaves that fall into discrete categories of form. Unlobed leaves, with undissected margins, predominate at proximal and distal nodes of shoots, while lobed leaves are most common at intermediate nodes. In this study we investigated the hypothesis that shoots of sassafras respond to environmental changes over the growing season by generating predictable nodal patterns for leaf morphology and physiology. We recorded leaf shape category and measured leaf surface area, node number, chlorophyll content, nitrogen content, and photosynthesis in four trees. Over 1,000 measurements of photosynthesis were made in situ, using the LI-Cor LI 6200 portable photosynthesis system. The two trees growing under heavy shade had few lobed leaves (2.0% and 18.8%) and often had negative carbon balance, with positive net photosynthesis occurring during sun flecks. The two trees growing in more open conditions had many more lobed leaves (56.3% and 61.0%) and higher, less variable net photosynthetic rates. As indicated by chlorophyll and nitrogen contents, the highest leaf photosynthetic rates occurred at intermediate nodes (nodes six to nine), and this was shifted distally along the shoot during the growing season. Leaves at intermediate nodes also had the largest surface areas and the greatest frequency of lobing. In comparative experiments with models, lobing was shown to enhance free-convectional heat loss relative to unlobed leaves of the same surface area. Due to their large surface area, these leaves also have the highest rates of whole leaf photosynthesis. Under conditions of equivalent photosynthetically active radiation, lobed leaves had higher rates of net photosynthesis than did unlobed leaves. We conclude that shoots of sassafras produce groups of leaves with predictably different morphological and physiological specializations.