Characterization of a new lectin involved in the protoplast regeneration of Bryopsis hypnoides

A group of coenocytic marine algae differs from higher plants, whose totipotency depends on an intact cell (or protoplast). Instead, this alga is able to aggregate its extruded protoplasm in sea water and generate new mature individuals. It is thought that lectins play a key role in the aggregation process. We purified a lectin associated with the aggregation of cell organelles in Bryopsis hypnoides. The lectin was ca. 27 kDa with a pI between pH 5 and pH 6. The absence of carbohydrate suggested that the lectin was not a glycoprotein. The hemagglutinating activity (HA) of the lectin was not dependent on the. presence of divalent cations and was inhibited by N-Acetylgalactosamine, N-Acetylglucosamine, and the glycoprotein bovine submaxillary mucin. The lectin preferentially agglutinated Gram-negative bacterium. The HA of this lectin was stable between pH 4 to pH 10. Cell organelles outside the cytoplasm were agglutinated by the addition of lectin solution (0.5 mg ml(-1)). Our results suggest that the regeneration of B. hypnoides is mediated by this lectin. We also demonstrated that the formation of cell organelle aggregates was inhibited by nigericin in natural seawater (pH 8.0). Given that nigericin dissipates proton gradients across the membrane, we hypothesize that the aggregation of cell organelles was proton-gradient dependent.

单细胞多核管状绿藻原生质团聚及发育研究

在实验室条件下研究了三种单细胞多核管状绿藻（藓羽藻、刺松藻和齿形蕨藻）原生质的团聚和发育过程。结果表明： 藓羽藻原生质团聚过程中，Na+或Ca2+浓度分别为0.5M和0.2 M时形成的藓羽藻亚原生质体数量最多，在原生质体团聚过程中细胞核发生了形变；藓羽藻无成熟叶绿体原生质能够在海水中团聚，并形成无成熟叶绿体的亚原生质体，该亚原生质体有细胞膜形成，但是无细胞壁形成，72小时后会死亡，分离纯化的线粒体在海水中不能团聚，分离纯化的叶绿体在海水中的团聚不是很明显，只是有2-3个叶绿体形成团聚体，而且数量也很少；在藓羽藻团聚过程中外源壳孢子和藓羽藻原生质会很快分开，这样壳孢子就不会被包围到藓羽藻原生质团聚体中，即使有的壳孢子被团聚进藓羽藻亚原生质体中，最后也是以藓羽藻亚原生质体的破裂而壳孢子发育而告终，同时加入壳孢子后还导致藓羽藻亚原生质体的发育方式发生了一定的变化，从以前的单极萌发变成二极萌发；在实验室条件下继代培养了藓羽藻原生质体三代，而且在团聚数量、大小和发育能力方面能够稳定遗传；野生藓羽藻原生质在6-12月份能够团聚，但是只能在8-12月份间发育； 刺松藻原生质体在碱性人工海水中会团聚形成亚原生质体，但是亚原生质体在72h内全部破裂，酶学和染色实验显示刺松藻原生质团聚过程中的絮凝胶状物质含有蛋白质和多糖类物质，松藻是一种非常合适的研究亚原生质体形成的实验模式材料；刺松藻的营养芽、游动细胞、丝状体和果胞都能够再生，刺松藻片断生长的最佳碳和氮浓度分别为：HCO3—C 3mM和NO3—N 70μM，刺松藻对所研究的不同氮源吸收能力基本相同； 齿形蕨藻的光饱和点为200 μmol/m2 s，最佳生长温度为25-30℃；齿形蕨藻片断的再生与光照强度成反比，而且只能在20-35℃间再生。齿形蕨藻原生质在碱性海水中能够团聚，但是与藓羽藻相比较数量非常的少。

Sporobolus stapfianus, a model desiccation-tolerant grass

Sporobolus stapfianus Gandoger, one of ~40 known ‘anabiotic’grass species (i.e. ‘able to regain vital activity from a state of latent life’), is the most versatile tool for research into desiccation tolerance in vegetative grass tissue. Current knowledge on this species is presented, including the features that suit it for investigations into the plant’s ability to survive dehydration of its leaf protoplasm. The main contributors to desiccation tolerance in S. stapfianus leaves appear to be: accumulation during dehydration of protectants of membranes and proteins; mechanisms limiting oxidative damage; a retention of protein synthetic activity in late stages of drying that is linked with changes in gene expression and in the proteomic array; and an ability to retain net synthesis of ATP during drying. S. stapfianus exemplifies an advanced stage of an evolutionary trend in desiccation tolerant plants towards increased importance of the dehydration phase (for induction of tolerance, for synthesis of protectants and for proteomic changes).

Crescimento e nutrição de plantas de leucena (Leucaena leucocephala (Lam.) R. de Vit) sob salanidade

Excessive salt can to promote water soil retention, reducing your availability to plants. Besides, they can interfere in protoplasm metabolism. The plants ability to survive in salinity conditions is an important factor to geographic distribution and agriculture in salinized regions. The objective of this work was to verify the effects of the NaCl in the growth, dry matter distribution and N, K, Ca, Mg, Na, and Cl content in young plants. The experiment was conducted in 'Leonard' pots, with nutrient solutions, with NaCl ( 0, 25, 50 and 100 mmol L(-1)). Increasing of NaCl concentration reduces growth and total dry matter. There was an increase of N and K content, in shoots, and N and Mg content in roots. There was an reduction in Mg content in shoots, and reduction of Ca content in roots with increasing of NaCl. Leucaena plants were inefficient to exclude Na and Cl, in shoots principally.

Naturalidade: o nível profundo da comunicaçao

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Geochemical and optical study of organic matter in some Pleistocene and Pliocene sediments at DSDP Leg 64 Holes

Pleisto-Pliocene hemipelagic and diatomaceous mud was recovered from Deep Sea Drilling Project (DSDP) Sites 474 through 481 in the Gulf of California. The organic matter is mostly marine and mainly derived from diatomaceous protoplasm. We found some continental organic matter in sediments near the bottom basalts or near dolerites (Holes 474A and 478). The organic matter in most of the samples is in an early stage of evolution.

Muramic lactam in peptidoglycan of Bacillus subtilis spores is required for spore outgrowth but not for spore dehydration or heat resistance

Bacterial endospores derive much of their longevity and resistance properties from the relative dehydration of their protoplasts. The spore cortex, a peptidoglycan structure surrounding the protoplasm, maintains, and is postulated to have a role in attaining, protoplast dehydration. A structural modification unique to the spore cortex is the removal of all or part of the peptide side chains from the majority of the muramic acid residues and the conversion of 50% of the muramic acid to muramic lactam. A mutation in the cwlD gene of Bacillus subtilis, predicted to encode a muramoyl-l-alanine amidase, results in the production of spores containing no muramic lactam. These spores have normally dehydrated protoplasts but are unable to complete the germination/outgrowth process to produce viable cells. Addition of germinants resulted in the triggering of germination with loss of spore refractility and the release of dipicolinic acid but no degradation of cortex peptidoglycan. Germination in the presence of lysozyme allowed the cwlD spores to produce viable cells and showed that they have normal heat resistance properties. These results (i) suggest that a mechanical activity of the cortex peptidoglycan is not required for the generation of protoplast dehydration but rather that it simply serves as a static structure to maintain dehydration, (ii) demonstrate that degradation of cortex peptidoglycan is not required for spore solute release or partial spore core rehydration during germination, (iii) indicate that muramic lactam is a major specificity determinant of germination lytic enzymes, and (iv) suggest the mechanism by which the spore cortex is degraded during germination while the germ cell wall is left intact.

Benzothiadiazole-Mediated Induced Resistance to Fusarium oxysporum f. sp. radicis-lycopersici in Tomato1

Benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), a synthetic chemical, was applied as a foliar spray to tomato (Lycopersicon esculentum) plants and evaluated for its potential to confer increased resistance against the soil-borne pathogen Fusarium oxysporum f. sp. radicis-lycopersici (FORL). In nontreated tomato plants all root tissues were massively colonized by FORL hyphae. Pathogen ingress toward the vascular stele was accompanied by severe host cell alterations, including cell wall breakdown. In BTH-treated plants striking differences in the rate and extent of fungal colonization were observed. Pathogen growth was restricted to the epidermis and the outer cortex, and fungal ingress was apparently halted by the formation of callose-enriched wall appositions at sites of fungal penetration. In addition, aggregated deposits, which frequently established close contact with the invading hyphae, accumulated in densely colonized epidermal cells and filled most intercellular spaces. Upon incubation of sections with gold-complexed laccase for localization of phenolic-like compounds, a slight deposition of gold particles was observed over both the host cell walls and the wall appositions. Labeling was also detected over the walls of fungal cells showing signs of obvious alteration ranging from cytoplasm disorganization to protoplasm retraction. We provide evidence that foliar applications of BTH sensitize susceptible tomato plants to react more rapidly and more efficiently to FORL attack through the formation of protective layers at sites of potential fungal entry.

Plasma und Zelle.

"Literaturverzeichnis" at end of each section.

La vie des mineraux, la plasmogenèse et le biomecanisme universal,

Plates have half-title: Atlas de plasmogenèse et de biologie universelles publié par le dr. Jules Félix d'après les travaux et les microphotographics des professeurs et des sayants Butschli...A. Herrera...Leduc...etc.

Ueber einwirkung der anästhetica auf des protoplasma und dessen biologisch-physiologischen eigenschaften ...

Lebenslauf.