液氮保存疫霉属菌种存活期检测

对Phytophthora和Peronophythora所属12个种29株菌在液氮中保存5年零8个月至6年零3个月后检测证明有68.9％的菌种存活下来。但有些种未能存活,这些种有Phytophthora colocasiae(XH30),P.drechsleri(ATCC15428),P.erythroseptica(ATCC36302)与Peronophythora litchii(ATCC 34595)。即使存活的菌种也不一定每个保存的菌株与菌块都存活。说明在液氮中也有存活力下降的现象。除菌种本身耐深冻贮藏特性不同外,贮藏前菌种培养的旺盛程度明显影响存活。对一些菌的致病性测定证明长期保存后致病力维持不变。液氮保藏不失为保持菌种长期不变的良好方法,只是要严格按要求掌握,并对菌的耐冻力先行了解。     

褐云玛瑙螺在我国的适生性研究

研究了世界上重要的有害生物－褐云玛瑙螺在我国的适生性。结果表明,该螺的致互最低和最高温度,发育起点温度,世代有效积浊分别为：０．２,４１．２,１２．０℃和２４２２．６日度。在此基础上,综合应用越冬越夏界限,有效积温法则和生物相似距方法,用ＱＵＩＣＫ ＢＡＳＩＣ计算机语言建立了褐云玛瑙螺在我国的适生性区划系统模型。     

SORBITOL IN THE EGGS OF THE SILKWORM, BOMBYX MORI

Sorbitol was found to be a normal and sole monosaccharide demonstrable in the late ovarian and in the early embryonic stages of the silkworm, Bombyx mori. This observation was first made on a line of non-diapausing polyvoltine Katsumata strain, but was later confirmed by the analysis of two other Katsumata lines and on several polyvoltine or bivoltine strains. The identification of the sugar extracted from the diapause eggs of a bivoltine strain and from the non-diapausing eggs of a Katsumata strain was based on analyses involving paper chromatography, paper electrophoresis and sorbitol dehydrogenase.     

CONJUGATED ECDYSONE IN THE EGGS OF THE SILKWORM, BOMBYX MORI

A high activity of molting hormone (ecdysone) was detected in the extract of unfertilized, diapausing and developing silkworm eggs. The active substance in the diapause eggs behaved as a highly polar molecule at partitioning between n -butanol and water, and also in TLC. The majority of the activity seems to be due to a conjugated ecdysone, since the polar active substance was changed to a less polar substance upon treatment with "snail enzymes".     

长毛对虾卵子皮层反应的研究

Morphology of the cortical reaction in the eggs of Penaeus penicillatus was studied with the light microscopy,scanning electron microscopy　and transmission electron microscopy. The cortical reaction is divided into four stages. These stages are unreacted stages, early stages, corona stages and dissipation stage. The cortical rods were released and formed a jelly coating around the surface of the egg. The jelly coating remained until the first cleavage had finished. In the end, the hatching membrane appeared around the egg. It is believed that these cortical reaction are responsible for the prevention of polyspermy by both a chemical and physical block and that also may establish a microenvironment inside a touch chorionic membrane for the developing embryo.     

VIABILITY OF THE CERVICAL EPITHELIUM DURING CARCINOGENESIS IN MICE

Autoradiograms of histological specimens from the cervix of seventy-five mice were analysed after in vivo injection with an RNA precursor. All nucleated, non-pyknotic cells and some mitotic figures were labelled, which suggested that the tissue was metabolically active (i.e. viable). Only the uppermost epithelial pyknotic cells were devitalized, as deduced by the morphological appearance of the cells and by the absence of label. The viability of the whole epithelium suggests that the previously reported focal distribution of proliferating and non-proliferating areas in the cervical epithelium of mice is a genuine phenomenon.     

CHANGES IN THE ORGANIZATION OF TUBULIN DURING MEIOSIS IN THE EGGS OF THE SURF CLAM, SPISULA SOLIDISSIMA

Polymerized tubulin can be stabilized in Kane's spindle isolation medium (HGL solution), isolated by differential centrifugation and then assayed by colchicine binding activity. In the eggs of the surf clam, Spisula solidissima, the level of particulate tubulin undergoes a series of specific changes during first meiotic division. In either unactivated ("interphase") eggs or metaphase eggs the amount of particulate tubulin was about 13% of the total at 23°C. The amount of particulate tubulin decreased shortly after activation, reaching a minimum value at about 5 min, the time of nuclear membrane breakdown. The particulate tubulin concentration then rose, reaching a maximum at metaphase, and then decreased again during anaphase, reaching a minimum at first polar body formation. In HGL homogenates of unactivated eggs a structure is present which has been shown to contain the interphase particulate tubulin (IPT). This structure consists essentially of a 10–20 µ granular sphere attached to a membranous material which is probably part of the egg cortex. These particles are absent at the time of nuclear membrane breakdown, when the level of particulate tubulin is minimal and when the first signs of spindle formation are visible. Electron microscopy of these particles by negative staining indicates that they are composed of microtubules associated with a granular matrix which may be a polymorphic aggregate of tubulin.     

EFFECT OF TEMPERATURE,LIGHT AND pH ON GROWTH,PHOTOSYNTHESIS AND RESPIRATION OF THE DINOFLAGELLATE PERIDINIUM CINCTUM FA. WESTII IN LABORATORY CULTURES1

Optimum light, temperature, and pH conditions for growth, photosynthetic, and respiratory activities of Peridinium cinctum fa. westii (Lemm.) Lef were investigated by using axenic clones in batch cultures. The results are discussed and compared with data from Lake Kinneret (Israel) where it produces heavy blooms in spring. Highest biomass development and growth rates occurred at ca. 23° C and ≥50 μE· m^?2·s¹ of fluorescent light with energy peaks at 440–575 and 665 nm. Photosynthetic oxygen release was more efficient in filtered light of blue (BG 12) and red (RG 2) than in green (VG 9) qualities. Photosynthetic oxygen production occurred at temperatures ranging from 5° to 32° C in white fluorescent light from 10 to 105 μE·m^?2·s^?1 with a gross maximum value of 1500 × 10^?12 g·cell^?1·h^?1 at the highest irradiance. The average respiration amounted to ca. 12% of the gross production and reached a maximum value of ca. 270·10^?12 g·cell^?1·h^?1 at 31° C. A comparison of photosynthetic and respiratory Q₁₀-values showed that in the upper temperature range the increase in gross production was only a third of the corresponding increase in respiration, although the gross production was at maximum. Short intermittent periods of dark (>7 min) before high light exposures from a halogen lamp greatly increased oxygen production. Depending on the physiological status of the alga, light saturation values were reached at 500–1000 μE·m^?2·s^?1 of halogen light with compensation points at 20–40 μE·m^?2·s^?1 and I_k-values at 100–200 μE·m^?2·s^?1. The corresponding values in fluorescent light in which it was cultured and adapted, were 25 to 75% lower indicating the ability of the alga to efficiently utilize varying light conditions, if the adaptation time is sufficient. Carbon fixation was most efficient at ca. pH 7, but the growth rates and biomass development were highest at pH 8.3.     

THYMINE IN THE ACID-SOLUBLE FRACTION OF ARBACIA EGGS

Mature Arbacia eggs were extracted with cold dilute perchloric acid, the extract concentrated, and the concentrate digested in hot perchloric acid. Thymine was recovered from the digest by paper chromatography, and the amount per egg found to be about 5 times the amount per sperm. This was the amount expected from previous experiments and is believed to represent all or almost all of the thymine in the egg. The result supports previous observations that DNA is absent from the mature egg although present in the nucleus of the egg in the germinal vesicle stage. No thymine could be recovered from a similar extract of 5,000 times as many sperm of the same species. The observations are consistent with the theory that DNA and its derivatives act as metabolic antagonists of the corresponding ribose compounds.     

THE ROLE OF ZINC IN THE GROWTH OF PLANT TISSUE CULTURES

Klein , Richard M., Emerita M. Caputo , and Barbara A. Witterholt . (New York Bot. Gard., N. Y., N. Y.) The role of zinc in the growth of plant tissue cultures. Amer, Jour. Bot. 49(4): 323–327. Illus. 1962.—Zinc-sufficient and zinc-deficient auxin-auxotrophic callus and auxin-prototrophic crown-gall cultures of Parthenocissus tricuspidatus were examined for their growth capacity and ability to synthesize tryptophan. Growth capacity decreased rapidly when zinc ion was withheld and tryptophan synthetase activity in vitro was reduced. Growth of –Zn crown-gall tissues was stimulated by either auxin or tryptophan and growth of –Zn callus cultures was stimulated by tryptophan.