Observations on the germinability in vitro of pollen from Camellia japonica L. (Theaceae)

Pollen grains from samples of Camellia japonica living in soil (A) and in greenhouse (B) were collected daily from just-opened anthers. The pollen was sown in various liquid media and incubated at 28 C. Higher germinative ability of A in comparison with B was observed and related to the relative humidity which is higher in soil than in greenhouse. This phenomenon recurs even if the composition of the culture medium is changed. However the composition of the medium greatly influences the percentage of germination of both A and B notwithstanding the environmental conditions. The pollen collected from anthers dehiscing in the first day of the anthesis has a high germinative ability which suddenly decreases in the ripe pollen of the following days.     

Behavioral "despair" in female rats and gonadal function

In female rats various parameters and rhythmical structure of forced swimming underwent unsignificant fluctuations during estrus cycle. Ovariectomy changed the swimming time course and increased the rhythmical index of depression without other serious disturbances of the behavioural "despair" test. After chronic estradiol these shifts were partially eliminated. It is suggested that considerable disturbances of gonadal function may be cause of desynchronousness which facilitated the development of depression.     

Pharmacokinetic disposition of pethidine under tolerance

Under tolerance, evoked by multiple doses of pethidine (PD), the serum and brain tissue content of PD was related to diminished analgesic activity. Even though in tolerant rats no enhancement of PD biotransformation in the liver could be recognized (as followed by the measurement of hepatic esterase and N-demethylase activity), the amounts of both PD and nor-PD excreted in urine were increased under tolerance. The authors conclude that the faster disposition of PD may contribute to the development of tolerance.     

Spread of fast thermowaves through the cerebral cortex produced by visual stimulation

Thermowaves spreading through the cerebral cortex were observed and investigated during acute experiments on white rats using a new technique — that of thermoencephaloscopy (TES) through the intact skull. These waves were induced by regular visual stimulation (at intervals of 1.5–3 min) or by initiating one of the flashes and spread through the cortex along trajectories of five basic types; amplitude of thermowaves: 0.005–0.1°C; length: 10–15 mm; duration 1.2–11.4 sec; velocity: 1–33 mm/sec; extent of pathway: 2–56 mm. They appeared with a high degree of probability (of 0.92) during the interval between 15 sec before and 26 sec after the flash. Numbers of moving waves declined by the point of stimulus application and rose by 7–8 sec after the flash. Waves arose in 50% of cases in the contralateral visual cortex (areas 17 and 18a), spreading to the midline and crossing to the ipsilateral hemisphere (areas 17, 18a, and 7). Local waves moving along a circular trajectory were also discovered in the contralateral visual cortex. Several types of wave, differing in trajectory, also arose in the ipsilateral visual cortex. Mechanisms and possible significance of this effect are examined.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 21, No. 4, pp. 467–475, July–August, 1989.     

Changes in quality of stallion spermatozoa during cryopreservation: Plasma membrane integrity and motion characteristics

Better procedures for freezing and thawing equine sperm are needed since variable fertility is obtained when cryopreserved sperm are used. To evaluate current methods of freezing equine sperm, we examined spermatozoal quality by means of two new techniques. These measured the integrity of plasma-acrosomal membranes by immunofluorescent analyses of binding of an antibody specific to the acrosome and evaluated eight parameters of spermatozoal motion using a fully automated computerized system. Five ejaculates from each of eight stallions were processed for freezing in egg yolk-lactose extender with 4% glycerol. Spermatozoal quality was assessed at four different points: at less than 15 min after collecting and before processing (Step 1); after centrifugation and just before freezing (Step 2); immediately after thawing less than 3 h after freezing (Step 3); and immediately after thawing 10 to 20 d after freezing (Step 4). Acrosome-specific monoclonal antibody detected differences (P <0.05) among steps and ejaculates within stallions. All parameters of spermatozoal motion, including the percentage of motile sperm, percentage of progressively motile sperm, curvilinear velocity, straight line velocity, linearity, amplitude of lateral head displacement, and radius of the average path for circularly swimming sperm, differed (P <0.05) among steps, and most of these parameters differed among ejaculates within a stallion and among stallions. For Steps 2 and 3, 62 and 37% of the sperm were motile, and 56 and 23% of all motile sperm had a curvilinear velocity of >100 mum/sec. Most damage to sperm occurred as a result of freezing-thawing, whereas centrifugation of sperm caused only minor damage.     

O dealkylation and aliphatic and aromatic hydroxylation of 3-methoxy-17 beta-estradiol by Aspergillus alliaceus

Aspergillus alliaceus UI 315 was examined for its ability to metabolize 3-methoxy-17 beta-estradiol. Preparative-scale incubations with this substrate afforded good yields of 6 beta-hydroxy-17 beta-estradiol, 4-hydroxy-17 beta-estradiol, and 4,6 beta-dihydroxy-17 beta-estradiol, which were identified by high-pressure liquid chromatography, 1H and 13C nuclear magnetic resonance, and high-resolution mass spectrometry.     

Tyrosination-detyrosination of tubulin and microtubules during the development of chick erythrocytes

The protein composition of nuclear matrices containing different amount of DNA was examined. It was found that, in matrices containing 2% to 80% of total DNA, the quantity of DNA-bound proteins remains relatively constant varying from 10% to 15% of total nuclear proteins. Electrophoretic patterns do not differ substantially, but autoradiograms with in vitro ¹²⁵I labelled proteins show quantitative variations in the actin content. Application of radioimmunoassay (RIA) enabled to determine the exact content of actin in GAT nuclei and nuclear matrices – 5 g/ml in nuclei, of which 50% are bound to DNA and 3001o being a component of the protein part of the nuclear matrix. These results are supported by electron microscopic data, where immunogold technique was performed on thin sections and spread material. The applied methods suggest that part of the nuclear actin is tightly bound (resistant to 2 M NaCI) to DNA and represents a component of the internal nuclear matrix.     

Renin release responses to in vitro prostaglandin challenge in the summer-active ground squirrel, Spermophilus lateralis

1. Using a renal cortical slice preparation from the summer-active ground squirrel, Spermophilus lateralis, resting renin release (RR) and tissue cyclic AMP content (TcAMPC) levels were found to be significantly higher and lower, respectively, than those previously reported for its hibernating counterpart. 2. At a 10(-5) M dose, PGE2 but not PGE1, PGF2-alpha or PGA1, significantly stimulated RR in the summer-active ground squirrel (SAGS). 3. Addition of agents which normally increase TcAMPC significantly potentiated the effect of PGE1, while preventing that of PGE2, on RR and TcAMPC. 4. Opposite TcAMPC changes may mediate the in vitro RR responses to PGE1 and PGE2 administration in the SAGS.