粘虫的胚胎发育

粘虫(Mythimna separata)胚胎发育经过卵裂及胚盘形成、胚带及原肠发生、胚带分节及附肢形成、体壁形成及背向闭合、胚胎反转和器官发生与形成6个时期。粘虫卵在25℃,胚胎发育至12h,胚带呈新月形或“C”字形。随着原肠发生,首先出现口陷与肛陷,与此同时,胚带逐渐伸长并开始分节。胚胎发育至32h,胚带头尾相接并呈波浪形弯曲,在胚胎反转前,胚胎发育至42h,前肠、后肠及马氏管已经形成。胚胎发育至54h时,胚动完成之 后,中肠才明显可见。同时将大量卵黄包围起来。神经系统的发生与气管形成始于原肠发生之后,至胚胎反转之前,神经节索才出现,随着胚动发生,神经节体积不断增大,腹神经索逐渐形成,纵走气管明显可见。     

The Resource-Based Mating System of the Mediterranean Pollen Wasp Ceramius fonscolombei Latreille 1810 (Hymenoptera, Vespidae, Masarinae)

Males of C. fonscolombei patrol and perch at water collection sites or at plants of Reseda, both of which are important resources for female brood care. The mating system can be classified as resource defense polygyny modified by the existence of alternative male mating tactics. Occupying temporary territories at watercollection sites constitutes the primary tactic which is more profitable for larger males. The secondary tactic of patrolling at flowers provides a nonaggressive alternative through which smaller males gain at least some mating success. Males at water collection sites occupy considerably smaller ranges but spend a higher proportion of time patrolling than males at flowers. They frequently grapple with other males, an activity that is absent at flowers. Males at water collection sites copulate about 2.5 times more frequently than males at flowers. The copulation frequency of the males at water collection sites is positively correlated with their body size, while copulation frequency is negatively correlated with body size at flowers. Males patrolling at water collection sites and males patrolling at flowers do not differ in body size, indicating that the decision between alternative mating tactics is not made relative to body size but is influenced by other factors.     

Compartmentation of the inulin space in mouse brain slices

(1) Mouse cerebrum slices swell in tris-buffered Krebs-Ringer medium. Swelling is rapid at first, then slows to a more or less constant rate. Even after 3 hr incubation, water content/g of tissue dry wt. shows no sign of an asymptotic limit. Swelling is the same at 37 degrees and at 0 degree. (2) Tissue water measured by incubation with tritiated water is equal to total tissue water measured by drying slices. Equilibration between tritiated water and tissue water is complete within 2 min. (3) Tissue liquid can be divided into three phenomenologically distinguishable compartments: first inulin space, which is the compartment permeable to inulin at both 0 degree and 37 degrees; second inulin space, which is the compartment permeable to inulin at 37 degrees but not at 0 degree; and 37 degrees non-inulin space, which is the compartment impermeable to inulin at both 0 degree and 37 degrees. The evidence for this is: (a) Penetration of inulin into tissue is greater at 37 degrees than at 0 degree. After the first 20 min the rate of penetration at 0 degree is approximately equal to the rate of penetration at 37 degrees, and only slightly less than the rate of increase of total tissue water. Therefore the smaller inulin space observed at 0 degree cannot be due to slower entry of inulin. (b) The inulin content of slices incubated in inulin-containing medium at 37 degrees and cooled to 0 degree in the same medium is the same as the inulin content of tissue incubated at 37 degrees without subsequent cooling. In contrast, the inulin content of tissues preincubated in inulin-free medium at 37 degrees and then incubated in inulin-containing medium at 0 degree is the same as the inulin content of tissues incubated in inulin-containing medium at 0 degree without preincubation at 37 degrees. Therefore the smaller inulin space at 0 degree than at 37 degrees can be due neither to a reversible temperature-dependent change in the size of one single inulin space nor to an irreversible, greater swelling of a single inulin space at the higher temperature, but is due to some portion of the 37 degrees inulin space becoming impermeable to inulin at 0 degree. (c) Some inulin is retained by tissue incubated with inulin at 37 degrees, then transferred to inulin-free medium at 0 degree; the amount of retained inulin is equal to the difference between inulin content of tissue incubated with inulin at 37 degrees and tissue incubated with inulin at 0 degree This confirms 3b above and in addition shows that inulin which has entered the second inulin space at 37 degrees is trapped there when this space becomes impermeable to inulin at 0 degree. (4) The penetration of the amino acids, L-lysine and D-glutamate at 0 degree is equal to the penetration of inulin at 37 degrees. This confirms the real existence of the 37 degrees inulin space at 0 degree, and shows that the barrier at 0 degree between the first and second inulin spaces does not exist for these substances. (5) The amino acids L-leucine and glycine penetrate total tissue water at 0 degree. L-leucine is actively transported at this temperature. (6) The amino acids alpha-aminoisobutyric acid, L-leucine, and L-lysine at 2 mM have no effect at 37 degrees on either the inulin space or the non-inulin space. (7) The inulin space is insensitive at 37 degrees to physiologically significant changes in the medium. In contrast, the non-inulin space is quite sensitive to these changes. Addition of D-glutamate greatly increases the non-inulin space; addition of ouabain or cyanide, or omission of glucose, increases the non-inulin space slightly; and replacement of Na+ ion by choline+ ion greatly decreases this space. These changes are independent and roughly additive.     

冬小麦对不同海拔气候条件的反应 Ⅲ.植株光合作用特征

我们在原地测量了840米和2150米两地种植的冬小麦“凤麦13”苗期、拔节期、抽穗期和灌浆初期的光合作用速率的日变化,光合作用速率对光量子通量密度的反应和CO_2补偿点。结果表明生育前期(苗期和拔节期)和后期(抽穗期和灌浆初期)光合作用速率的一日内变化形式相反,而且低地种植的冬小麦其光合速率在前期高于高地种植的,后期高地种植的冬小麦有比低地高的光合速率。光饱和点基本相同。光补偿点在生育前期高地小麦比低地小麦低,而后期低地小麦的的光补偿点减低,并低于高地小麦的。高地小麦的光补偿点比较稳定。CO_2补偿点高地小麦比低地的较低。并就两地气候条件讨论了上述差异。     

Optimal conditions for hepatitis B core antigen production in shaked flask fermentation

The effects of various environmental factors such as pH (5, 6, 7, 8 and 9), temperature (30, 37 and 40°C) and rotational speed (150, 200 and 250 rpm) on the growth and the hepatitis B core antigen (HBcAg) production ofEscherichia coli W3110IQ were examined in the present study. The highest growth rate is achieved at PH 7, 37°C and at a rotational speed of 250 rpm which is 0.927 h⁻¹. The effect of pH on cell growth is more substantial compared to other parameters; it recorded a 123% different between the highest growth rate (0.927 h⁻¹) at pH 7 and lowest growth at pH 5. The highest protein yield is achieved at pH 9, rotational speed of 250 rpm and 40°C. The yield of protein at pH 7 is 154% higher compared to the lowest yield achieved at pH 5. There is about 28% different of the protein yield for theE. coli cultivated at 250 rpm compared to that at 150 rpm which has the lowest HBcAg yield. The yield of protein at 40°C is 38% higher compared to the lowest yield achieved, at 30°C.     

Enhancement of transpiration by ethylene is responsible for absence of internodal elongation in floating rice at low humidity

Internodal elongation in floating rice (Oryza sativa) is known to be enhanced by treatment with ethylene or gibberellic acid (GA3) at high relative humidity (RH). However, ethylene-induced internodal elongation is inhibited at low RH, while GA3-induced internodal elongation is hardly affected by humidity. We examined the effects of ethylene and GA3 on the rate of transpiration in stem segments incubated at 30% or 100% RH. Ethylene promoted the transpiration of stem segments at 30% RH, but not at 100% RH, while GA3 had little effect on transpiration at either 30% or 100% RH. We propose that the absence of ethylene-induced internodal elongation at low RH is due, at least in part, to ethylene-induced transpiration.     

Differential fixation of poly(L-arginine) and poly(L-lysine) by tannic acid and its application to the fixation of collagen in electron microscopy

A differential fixation of poly(L-arginine) and poly(L-lysine) has been demonstrated by means of cellulose acetate electrophoresis and colorimetric titration. Electrophoresis showed that at pH 3.0 and concentrations between 0.025% and 2% the reagent interacts with poly(L-arginine) but not with poly(L-lysine). at pH 7.5, however, poly(L-lysine) also reacts, although at a higher concentration of tannic acid than was required to fix poly(L-arginine) at this pH. Colorimetric titration revealed that for poly(L-arginine) the reaction with tannic acid commences at pH 3.0 and is complete at pH 4.1 whereas for poly(L-lysine) the reaction commences at pH 3.5 and is complete at pH 4.9. It is suggested that the reaction is predominantly electrostatic. The results are discussed in relation to the use of tannic acid as a protein fixative in electron microscopy.     

福建柏开花与结实物候期的研究

福建柏1年2次花期,春花期4—5月,果期当年10月,种子无生活力;秋花期9～10月,果期翌年10月,种子有生活力,有效花期在秋季。开花结实的生物学及物候学特性与适生区的地点、地类、海拔、温度等地理气候因子紧密相关,总体变异规律：秋花期、球果成熟期、种子散落期山区比半山区早,半山区比丘陵区早,高海拔地区比低海拔地区早．发芽率山区〉半山区〉丘陵区。     

Developmental patterns of the hermaphroditic gonad in dicyemid mesozoans (Phylum Dicyemida)

Abstract. The development of the hermaphroditic gonad, the infusorigen, was studied in fixed specimens of 16 species belonging to four genera ( Conocyema, Dicyema, Dicyemennea , and Pseudicyema ) of dicyemid mesozoans. In addition, the literature on the cell lineages of infusorigens of eight other species was reviewed. After an agamete (axoblast) undergoes an unequal first division, excluding a small cell (the paranucleus), the resulting large cell divides to form the infusorigen. Five infursorigen cell lineage patterns can be identified: type I, both the first oogonium and the first spermatogonium are produced at the third division; type II, the first spermatogonium is produced at the second division and the first oogonium is produced at the third division; type III, the first spermatogonium is produced at the second division and the first oogonium is produced at the fourth division; type IV, the first oogonium is produced at the second division and the first spermatogonium is produced at the third division; and type V, the first oogonium is produced at the second division and the first spermatogonium is produced at the fourth division. Later development is similar in members of all genera. Mature infusorigens are similarly organized in all species examined. Sizes of agametes and infusorigen axial cells, the number of infusorigens, and the type of reproductive strategy were not correlated with infusorigen developmental patterns or cell lineage patterns.     

Climate and climatic variability at Lake Myvatn

The climate of the Lake Myvatn region is examined through the use of weather station data, using the years from 1971 to 2000 as a reference period. Variations in mean monthly temperature and precipitation at Reykjahlid (Myvatn) are compared with variations at seven other weather stations in north east Iceland. The area is drier and colder than coastal stations and exhibits a seasonal cycle in temperature that is larger than found at the coast. The temperature is significantly influenced by the number of sunlight hours only during the summer months. During summer, the influence of a sea breeze circulation can be clearly identified.The variability of climate since 1936 is also examined in comparison with the seven other weather stations. It is found that temperature variations at the different stations are highly correlated, but for precipitation the correlation is significant but much weaker.The influence of the large scale atmospheric circulation on temperature and precipitation at Lake Myvatn is also examined. It is found that the air temperature at Lake Myvatn is most sensitive to an east-west dipole in the large scale sea surface pressure field, i.e. to a pattern that is very different from the spatial pattern associated with the North Atlantic Oscillation (NAO). Precipitation at Lake Myvatn is to some degree influenced by the NAO, but generally precipitation is associated with northerly winds and cold temperatures whereas southerly winds at Lake Myvatn are likely to be drier.     

Are two photoreceptors involved in the flowering of a long-day plant?

The effect of daylength extension with narrow spectral bands on the flowering of a long-day plant, Brassica campestris L. cv. Ceres, was investigated to obtain clues to the identity of the photoreceptor involved. Extension of a 9 h photoperiod with 5 h of light pulses at various wavelengths resulted in maximal flowering occurring after irradiation at 710 nm, less at 730 nm, and none at 550, 660 and 750 nm. Flowering at 710 and 730 nm was negated by simultaneous exposures at 550 nm, but not at 660 nm. A short preirradiation at 660 nm enabled a following irradiation at 750 nm to induce flowering. This latter induction was prevented by 550 nm irradiation.
Short flashes of light at 710 nm induced flowering that was negated by a following flash at 550 nm but not at 660 nm. The negation by 550 nm radiation was prevented by subsequent flashes at 710 nm, indicating photoreversibility. A flash at 660 nm enabled subsequent light flashes at 750 nm to initiate flowering that was reversed by a following 550 nm flash.
From the results showing the necessity of red and far-red lights, it is proposed that flowering in this long-day plant is due to two photoreceptors - one is phytochrome and the other an unknown pigment with far-red, green photoreversible properties. By using fluence response data, it is deduced that the unidentified photoreceptor has weak absorption bands in the far-red, but has a strong absorption band in the green. Flowering is induced when effects of red light absorbed by phytochrome interact with effects of far-red light absorbed by the unidentified photoreceptor.     

Tumour biology of a breast cancer at least partly reflects the biology of the tissue/epithelial cell of origin at the time of initiation - a hypothesis

A hypothesis is presented suggesting that initiation of breast epithelial cell freezes the cell at least partly according to the development/differention of cell at the time of initiation. Tumour biology will mimic the physiology of normal cell development at the time of initiation and this is preserved at least partly onwards. Also preferentially, tumours will develop from the cell type that is proliferating at the time of initiation. This may explain the overrepresentation of different types of histology in breast cancer in relation to age of the woman. The development of each tumour may follow at least partly a distinct pathway of evolution.     

Relationship Between Ethylene Release,Membrane Permeability and Activity of Polyphenol Oxidase Changes of Duck (Pears Pyrus bretschnideri Rehder) During Low Temperature Storage

Duck pear (Pyrus bretschneideri Rehder) tends to develop browning core after 55 to 60 days storage at low temperature (0℃). Following physiological changes of the duck pear during storage at different temperature were investigated: (1) As compared with 20℃, ethylene release is obviously decreased and its peak is retarded for 15 days at 0℃. Levels of internal ethylene are variant at different individuals harvested at same time. Concentrations of internal ethylene are in accord with ethylene release. The higher internal ethylene is, the easier the pear core becomes brown. (2) At 0℃, activity of polyphenol oxidase in the core increases with ethylene release enhancement. After ethylene peak passes, its activity is lower than before. (3) The electric conductivity of cores is higher at 0℃ than at 20℃. During post climacteric period, the electric conductivity increases irreversibly, then browning core occurs. From above results, it is concluded that interactions between two factors induce the browrang core of the duck pears at low temperature. One is chilling injury caused by low temperature, another is ethylene function. They stimulate the activity of polyphenol oxidase and enhance the membrane permeability.     

Effects of Elevated Temperatures on Mengovirus Ribonucleic Acid Synthesis and Virus Production in Novikoff Rat Hepatoma Cells

The production of mengovirus in Novikoff rat hepatoma cells is progressively reduced with an increase in incubation temperature of the cells from 34 to 40 C, in spite of the fact that about the same amounts of single-stranded and double-stranded viral ribonucleic acid (RNA) are synthesized at 34, 37, and 40 C; the rate of overall protein synthesis is as high at 40 C as at 37 C. At 40 C, progeny viral RNA accumulates in an undegraded form without being incorporated into virus particles. The results suggest that virus maturation is preferentially inhibited at supraoptimal temperatures. At 42 C, on the other hand, no viral RNA is produced and no viral RNA polymerase activity is detectable in cell lysates. Failure of infected cells to form viral RNA polymerase at 42 C is probably due to an impairment of protein synthesis since most of the polyribosomes are rapidly lost during incubation at 42 C and the rate of amino acid incorporation into protein is 70% lower at 42 C than at 37 C. When infected cells are shifted from 37 to 42 C during the period of active viral RNA synthesis, viral RNA polymerase activity is rapidly lost from the cells, and viral RNA synthesis ceases within 45 min. In contrast, the RNA polymerase is as active in vitro at 42 C as at 37 C, and the activity is relatively stable at 42 C.     

Spatial variation of biochemical and ecological phenotypes in Drosophila: Electrophoretic and quantitative variation

Electrophoretic variation at three enzyme loci-alcohol dehydrogenase (Adh), glycerophosphate dehydrogenase (Gpdh), triosephosphate isomerase (Tpi)- is compared in Australian Drosophila melanogaster populations at three levels of spatial heterogeneity; among breeding sites, within populations, and between populations at the geographic level. Heterogeneity at the breeding site level greatly exceeds that among adults within populations, indicating greater intermixing at the mobile adult stage than at the developmentally immature and less migratory larval stage. Heterogeneity at the microspatial level is large relative to the geographic level at two of these loci. Spatial patterns of variation in ecological phenotypes are also considered. It is argued that electrophoretic variants may contribute little to an understanding of this quantitative variation, and that a more useful approach in ecological genetics is to consider ecological phenotypes as primary data.     

自然和热凝固的人肝组织对KTP/YAG激光的光学特性的比较研究

本文采用双积分球测量系统和Inverse Add ing-Doub ling方法,研究了自然和热凝固的人肝组织对532nm的KTP激光和1 064 nm的Nd:YAG激光的光学特性。结果表明:热凝固的人肝组织对532 nm的KTP激光的吸收系数较自然的肝组织的吸收系数增大了23.5%(P<0.05),热凝固的肝组织对1 064 nm的Nd:YAG激光的吸收系数较自然的肝组织的吸收系数减小了34.3%(P<0.05)。热凝固的人肝组织对532 nm的KTP激光的散射系数较自然的肝组织的散射系数增大了4.50倍(P<0.05),热凝固的肝组织对1 064 nm的Nd:YAG激光的散射系数较自然的肝组织的散射系数增大了6.41倍(P<0.05)。热凝固的人肝组织对532 nm的KTP激光的各向异性因子较自然的肝组织的各向异性因子减小了5.47%,热凝固的肝组织对1 064 nm的Nd:YAG激光的各向异性因子较自然的肝组织的各向异性因子减小了1.95%。     

Two temperature-sensitive photosystem II mutants of pea

Two nuclear gene mutants of pea, chlorotica-887 and chlorina-5756, are temperature-sensitive in the development of photosystem II activity. Low temperature flourescence emission spectra of leaves show that the peak at 697 nm from the reaction center of photosystem II is present when the mutants have been grown at 18°C, but absent when they have been grown at 30°C. For leaves of chlorina-5756 grown at 18°C the relative size of the peak at 697 nm is reduced compared to that of leaves of the wild type or chlorotica-887 grown at this temperature. Flourescence induction curves of leaves from wild type plants and chlorotica-887 grown at 18°C possess two steps, while those of leaves from chlorina-5756 grown at 18°C or 30°C and chlorotica-887 grown at 30°C show at fast rise to the maximal level of fluorescence. Measurements on chloroplasts isolated from the mutants indicated that the photosystem I activity per g leaf material is comparable for plants grown at 18°C and plants grown at 30°C. In contrast, no photosystem II activity was detected when the mutants had been grown at 30°C. It is suggested that these mutants are affected in a component required for the assembly of functional photosystem II complexes.     

Cohesion and centromere activity are required for phosphorylation of histone H3 in maize

Haspin‐mediated phosphorylation of histone H3 at threonine 3 (H3T3ph) promotes proper deposition of Aurora B at the inner centromere to ensure faithful chromosome segregation in metazoans. However, the function of H3T3ph remains relatively unexplored in plants. Here, we show that in maize (Zea mays L.) mitotic cells, H3T3ph is concentrated at pericentromeric and centromeric regions. Additional weak H3T3ph signals occur between cohered sister chromatids at prometaphase. Immunostaining on dicentric chromosomes reveals that an inactive centromere cannot maintain H3T3ph at metaphase, indicating that a functional centromere is required for H3T3 phosphorylation. H3T3ph locates at a newly formed centromeric region that lacks detectable CentC sequences and strongly reduced CRM and ZmBs repeat sequences at metaphase II. These results suggest that centromeric localization of H3T3ph is not dependent on centromeric sequences. In maize meiocytes, H3T3 phosphorylation occurs at the late diakinesis and extends to the entire chromosome at metaphase I, but is exclusively limited to the centromere at metaphase II. The H3T3ph signals are absent in the afd1 (absence of first division) and sgo1 (shugoshin) mutants during meiosis II when the sister chromatids exhibit random distribution. Further, we show that H3T3ph is mainly located at the pericentromere during meiotic prophase II but is restricted to the inner centromere at metaphase II. We propose that this relocation of H3T3ph depends on tension at the centromere and is required to promote bi‐orientation of sister chromatids.     

Movements of water in cells of Nitella

When one end of a Nitella cell (A) is bathed in water and a solution of sucrose is placed at the other (B) we find that water enters at A, travels along inside the cell, and escapes at B. The solutes which cannot pass out through the protoplasm at B remain behind so that the osmotic pressure increases at B and diminishes at A until equilibrium is reached and the motion stops. An equation is given which enables us to predict with considerable accuracy the amount of flow required to produce equilibrium.     

Structure of gamma-chymotrypsin in the range pH 2.0 to pH 10.5 suggests that gamma-chymotrypsin is a covalent acyl-enzyme adduct at low pH

Crystals of gamma-chymotrypsin (gamma-CHT) grown at pH 7.0 are stable from pH 2.0 to 11.0. Crystalline gamma-CHT therefore provides an unusually favourable system to observe the structure of a protein and its bound solvent over a broad range of pH. In this report we describe the high-resolution refined structure of gamma-CHT at pH values of 2.0, 7.0 and 10.5. The apparent tetrapeptide seen bound in the active site of gamma-CHT at pH 7.0 is also present at pH 2.0 and 10.5 although it is better defined at low pH. A comparison of the respective structures shows that there is additional electron density in the low pH structure at the point where the side-chain of Ser 195 approaches most closely to the presumptive inhibitor. This suggests that the adduct is most likely to be covalently linked to the enzyme at low pH and to be non-covalent at higher pH. As the pH is lowered from 7.0 to 2.0, the side-chain of His 40 rotates approximately 120 degrees about its C alpha-C beta bond and, in concert, the side-chain of Gln 34 also rotates approximately 140 degrees about its C alpha-C beta bond. Apart from these localized rearrangements in the vicinity of His 40, the structure of gamma-CHT at pH 2.0 is very similar to that at neutral pH. The structure of gamma-CHT at pH 10.5 is also seen to be almost identical with that at neutral pH. There is no indication that the internal salt bridge between Asp 194 and the alpha-amino group of lle 16 begins to dissociate at pH 10.5. With the exception of the vicinity of His 40, the structure of the bound solvent in the crystal structures at low, neutral and high pH is very similar.(ABSTRACT TRUNCATED AT 250 WORDS)