Body mass changes in waders (Charadrii) in a high arctic area at northern Taimyr, Siberia

Body mass data were collected for 5 species of tundra waders during 6 breeding seasons to study variation in nutrient reserves relative to high arctic climatic conditions and the stage of reproduction. Structural size was accounted for by the 1st Principal Component of external linear measurements: wing length, bill length and tarsus length. SandpipersCalidris spp. were on average lighter in phenologically late seasons, while mass of Turnstones (Arenaria interpres) was similar in all years. Mass of waders was lower during brood-rearing than during incubation. Body mass during pre-nesting was most variable between years, reflecting the unpredictable weather conditions in this period. Monogamous species (KnotsCalidris canutus and Turnstones) began to breed earlier, and were on average, as heavy during the pre-nesting period as during incubation. In contrast, species with a proven or suspected rapid double-clutch breeding system (Little StintsC. minuta and SanderlingsC. alba) began to breed later and had during the laying period masses close to those of adults attending broods, and lower than during incubation. Body mass of the two latter species and Curlew Sandpipers (Calidris ferruginea) varied during incubation, reaching peak at 7 to 13 days after clutch completion.

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Zusammenfassung Von fünf Tundra-Watvogelarten wurden in sechs Brutperioden Daten zur Körpermasse gewonnen, um die Dynamik der Energiereserven in Abhängigkeit von den klimatischen Bedingungen der Hocharktis und vom Fortpflanzungsstadium zu analysieren. Der Einfluß der Körpermaße auf die Masse wurde bei der statistischen Auswertung durch die Einbeziehung der 1. Hauptkomponente von Flügel-, Schnabel- und Tarsuslänge berücksichtigt. StrandläuferCalidris spec. erwiesen sich in späten Jahren als leichter, während in der Körpermasse von Steinwälzern (Arenaria interpres) keine Unterschiede festgestellt werden konnten. Die Körpermasse aller untersuchter Arten war während der Betreuung der Jungvögel geringer als während Brütezeit. Die Masse in der Zeit vor der Brut variierte in Übereinstimmung mit den wechselnden Wetterbedingungen in den einzelnen Jahren am stärksten. Monogame Arten (KnutCalidris canutus und Steinwälzer) begannen früher mit der Fortpflanzung; ihre Körpermasse in der Phase von der Brut und während der Brütezeit war im Mittel etwa gleich. Im Gegensatz dazu begannen Arten, bei denen ein Doppelbrutsystem nachgewiesen wurde oder vermutet wird (ZwergstrandläuferC. minuta und SanderlingC. alba), später mit dem Nestbau, wobei die Körpermasse auf ein Niveau absinkt, das dem während der Betreuung der Jungvögel nahekommt und geringer ist, als das während der Brütezeit. Bei den beiden letzten Arten sowie beim Sichelstrandläufer (Calidris ferrugunea) veränderte sich die Körpermasse während des Brütens und erreichte ein Maximum zwischen dem 7. und dem 13. Tag nach Beendigung der Eiablage.

     

Nociceptive atrophy of the rat soleus muscle induced by bone fracture: a morphometric study

Zachaová, Gisela, HelenaKnotková-Urbancová, Pavel Hník, andTomá Soukup. Nociceptive atrophy of the rat soleus muscle induced by bone fracture: a morphometric study.J. Appl. Physiol. 82(2): 552-557, 1997.Reflex atrophy of the soleus muscle induced by ipsilateralmetatarsal bone fracture in Sagatal-anesthetized adult male rats wasstudied by using two-dimensional stereological methods 7 days after theoperation. When compared with contralateral solei, the wet weight ofthe experimental soleus muscles was decreased by ~24% and the areaof the entire muscle section by ~29%. In atrophied solei, the numberof type 1 fibers was lower by ~8%, resulting in lower total numberof fibers (by ~6%). This indicates that slow motor units might bemore sensitive to nociceptive stimulation. However, with respect to thefiber area, the reflex atrophy induced by metatarsal bone fracture inthe rat soleus muscle resembles simple atrophy after 7 days, as themean muscle fiber area was decreased by ~26% with no significantdifference between atrophy in type 1 and type 2a fibers (by 27.3 and23.0%, respectively).

     

Centrifugal cell hybridization

Centrifugation of cell suspensions containing two or several cell types at forces up to 2 million g results in several basic events in succession: 1. Intracellular stratification. 2. Extrusion of the most dense cell parts (nuclei or cytoplasmic components) and their penetration into an adjacent cell in the compact sediment. Such introduction of protoplasmic elements from one cell into another is considered as centrifugal hybridization and fusion of cells. It differs from other methods of cell hybridization by its selectivity for cell components. 3. Further intermingling and mixing of cells into a fused protoplasmic mass. 4. With continuing increase of centrifugal force fractions of subcellular components are formed from the protoplasmic mass. These components are presumably viable since cells are not exposed to chemical treatment. Morphological demonstration of hybridization is based on centrifuging microscopy and on labeling donor cells or recipient cells by staining or fluorescence. Genetic evidence can be provided by cultivation of hybrid cellsin vitro and their cloningin vivo.     

Cytotaxonomic study ofTragopogon L. in czechoslovakia

Karyotypes ofTragopogon orientalis L. subsp.orientalis, T orientalis L. subsp.leiocarpos (Sauter)Trnka,T. pratensis L.,T. minor Miller,T. dubius Scop. subsp.dubius andT. dubius Scop. subsp.major (Jacq.)Vollmann were studied. The occurrence in Slovakia ofT. pratensis was karyologically proved.     

Vasotocin, melatonin and narcolepsy: Possible involvement of the pineal gland in its patho-physiological mechanism

Both the pineal nonapeptide hormone arginine vasotocin (AVT) (2.5 μg) administered intra-nasally and the pineal indole melatonin (50 mg) administered intravenously to three male narcoleptics (two with auxiliary symptoms and one with sleep attacks only), dramatically increased the amount of REM sleep and decreased REM sleep latency. The duration of the sleep onset REM periods in the two narcoleptics with auxiliary symptoms increased by more than 100 percent after AVT and melatonin administration. In the narcoleptic with sleep attacks only both AVT and melatonin induced REM periods at sleep onset. The hypothesis is advanced that narcolepsy represents an impairment of the melatonin-AVT control in the induction and circadian organization of REM sleep associated with an immaturity of REM triggering centers.     

Identification of two Thormählen-positive compounds from melanotic urine by gas chromatography—mass spectrometry

The isolation of two Thormählen-positive compounds from the urine of a patient with malignant melanoma and the elucidation of their structure by gas chromatography—mass spectrometry is described. The compounds were isolated using a poly-N-vinylpyrrolidone column and separated by preparative thin-layer chromatography. After elution they were analyzed by gas chromatography and gas chromatography—mass spectrometry as their trimethylsilyl derivatives and after hydrolysis also as their tert.-butyldimethylsilyl derivatives. The results showed the main Thormählen-positive compound A to be the glucuronide of 5-hydroxy-6-methoxyindole, whereas the minor compound AX appeared to be the glucuronide of its isomer 6-hydroxy-5-methoxyindole.     

Isolation of Allium pollen protoplasts

Studies on protoplasts isolation were carried out with mature pollen grains of 29 samples of species of Allium aflatunense, A. cepa, A. fistulosum, A. karataviense, A. longicuspis, A. nutans, A. odorum, A. sativum and A. schoenoprasum. Surface sterilized pollen grains drifted from crushed anthers were incubated in an enzyme solution containing 1% (w/v) cellulase Onozuka R-10, 1% (w/v) Macerozyme R-10, 0,5 mol l^-1 sucrose and the basal salts of Nitsch medium. Protoplasts were released within 3 to 120 min, either from the pollen grain, through a slightly disturbed germination pore (narrow aperture), or through a wider aperture, when the exine surrounding the germination pore was disturbed. For the first time, protoplasts were obtained from 13 genotypes of 6 Allium species, at a rate of 1 to 30% of the digested intact pollen grains, depending on the genotype.     

Fusion of hamster and pig zona-free eggs stimulated by boar and guinea pig sperm at fertilization in vitro

In the course of in vitro fertilization of zona-free hamster and pig eggs by boar and guinea-pig spermatozoa it was observed that homologous and heterologous eggs fused together, forming cell hybrids between two or more cells. The fusogenic activity was attributed to spermatozoa and this was the hypothesis tested. The fusogenic activity (coinciding with sperm penetration activity) was dependent on the duration of sperm preincubation, which may be regarded as capacitation in vitro. Fusion occurred only after 3 hr of sperm preincubation and a narrow optimum was detected at 4–4.5 hr. Fusion of eggs was also dependent on sperm concentration. A relatively high proportion of fusions was observed at a sperm concentration of 4.0 × 10⁴ per ml and an optimum was attained at a concentration of 5.0 × 10⁵ per ml. The first fusions were observed at 90 min after semination. After 3 hr more than a half of the eggs reacted, and by 20 hr of incubation 80% of ova were fused. The fusability of eggs was tested and found to occur at 14 hr after ovulation. The fusion process was also studied using transmission electron microscopy. It is supposed that the process of egg fusion may be caused either by a similar mechanism to sperm-egg fusion, or by products released during the sperm acrosome reaction.     

The influence of the electric diffusion potential on delayed fluorescence light curves of chloroplasts treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea

The potassium salt-induced transient increase of delayed fluorescence yield was studied in pea chloroplasts treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea.A simple kinetic model is proposed to account for the actinic light intensity dependence of the delayed fluorescence enhancement by the transmembrane diffusion potential induced by sudden salt addition. The electric field dependence of the rate constants for the recombination of primary separated charges with and without subsequent electronic excitation of reaction center chlorophyll was obtained.From the value of enhancement of delayed fluorescence by salt concentration gradients at saturating actinic light intensity, it is concluded that the distance, normal to thylakoid membrane surface, between the primary acceptor and the donor of Photosystem II is smaller than the membrane thickness.