Antagonismusin vitro vonBacillus spp. gegenüberRhizoctonia solani undPythium spp.

Zusammenfassung Es konnten 132Bacillus-Stämme isoliert und gegenüber7 Rhizoctonia-solani- und 6Pythium-Stämmen auf Antagonismusin vitro untersucht werden. Die gefundenen Antagonisten hemmten die Pilzisolate unterschiedlich stark, so daß Gemische von Antagonisten für die Praxis zu empfehlen sind.

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Antagonismin vitro ofBacillus spp. againstRhizoctonia solani andPythium spp.

There were 132Bacillus-strains isolated and tested for antagonism against 7 strains ofRhizoctonia solani and 6 strains ofPythium spp. The isolated antagonists didn't show a uniform effect against the tested strains ofRhizoctonia solani andPythium spp. For an application in practice it will be better to use a mixture of antagonists.

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Mit 4 Abbildungen und einer Tabelle     

Isolation und Pathogenität vonRhizoctonia solani Kühn an Gurken und Buschbohnen

Zusammenfassung Es wurden 79Rhizoctonia solani-Isolate von verschiedenen Orten in Baden-Württemberg isoliert. Es konnten Isolate gefunden werden, die gegenüber Gurken und Bohnen pathogen waren. Bei Bohnen kann das Sproßgewicht als leicht zu erfassender Parameter für die Quantifizierung der Schadwirkung benutzt werden. Eine trockene Lagerung von mitRhizoctonia solani durchwachsenen Haferkörnern erwies sich als besonders geeignet für eine Stammkulturhaltung.

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Isolation and pathogenicity ofRhizoctonia solani to cucumber and bean

79Rhizoctonia solani strains were isolated from different locations in Baden-Württemberg. Some of these strains were pathogenic against cucumber and bean. The sprout-weight of bean can be used as an easy-to-measure parameter for quantification of the damage caused by teh fungus. The dry storage of oat seeds, previously inoculated withRhizoctonia solani, has been shown to be the best method for long-term storage.

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Mit einer Abbildung und 6 Tabellen     

Überleben einerXanthomonas campestris pv.pelargonii-Mutante in einjähriger Komposterde

Zusammenfassung Das Überleben vonXanthomonas campestris pv.pelargonii wurde anhand einer Mutante in einjährigem Kompost untersucht. In der Versuchsvariante 1, bei der die Bakterien mit Komposterde vermischt wurden, konnte die Mutante Xc3b nach 15 Monaten nicht mehr nachgewiesen werden. Unter diesen Bedingungen war es den Bakterien möglich, 14 Monate im Kompost zu überleben. In der Versuchsvariante 2, bei der Komposterde mit Bakterien und zusätzlich noch mit infizierten Pelargonienstielen eingebracht wurden, konnten dieXanthomonas-Mutanten noch nach 26 Monaten nachgewiesen werden.

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Survival of a mutant ofXanthomonas campestris pv.pelargonii in one year old compost

Survival of phytopathogenicXanthomonas campestris pv.perlargonii in a one year old compost was investigated by use of a mutant. In the variant 1, in which the compost soil was mixed with the bacteria, the mutant Xc-3b could not be detected after 15 months. Under these conditions the bacteria were able to survive for 14 months in the compost. In the variant 2, in which the compost soil was mixed with bacteria andXanthomonas-infected geranium stems, it could be found even after 26 months.

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Mit 2 Abbildungen     

Changes in enzyme activities,soluble sugars and phenols during in vitro adventitious shoot regeneration from leaflet explants of <Emphasis Type="Italic">Albizia procera</Emphasis> (Roxb.) Benth

Changes in nitrate reductase, i.e. NR (E.C. 1.7.1.1) activity, peroxidase (E.C. 1.11.1.14) activity, soluble sugars and phenols were monitored at various time intervals from day 0 to 60 during in vitro adventitious shoot regeneration from leaflet explants of Albizia procera (Roxb.) Benth. The explants were incubated on semi-solid Murashige and Skoog medium supplemented with 2.6 g l^?1 Phytagel^®, 2.5% sucrose, 10 μM BAP, 1 μM NAA and 15 μM AgNO₃. NR activity, soluble sugars and phenols exhibited initial sharp rise on around day 20 followed by steep decline on day 25, whereas peroxidase activity peaked on day 50, highlighting significance of early input of nitrogen and energy and late emergence of lignification process for cellular differentiation and organization into adventitious shoot primordia. Morpho-anatomical changes in leaflets at various stages of in vitro adventitious shoot formation also followed the endogenous biochemical pattern.     

Population status and regeneration of a tropical clumping bamboo <Emphasis Type="Italic">Schizostachyum dullooa</Emphasis> under two management regimes

Schizostachyum dullooa (Gamble) Majumder ‘dolu bamboo’ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population status and regeneration in Cachar tropical semi evergreen forest under private property resource management (PPRM) and common property resource management (CPRM) regimes. Population status revealed current-year, one-year, two-year and three-year-old culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent in CPRM and population status was thus represented by current year (83%), one-year (16%) and two-year (1%) old culms. Net change, rate of change and % gain in population for different age classes showed the prevalence of management practices under CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and 59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term economic and ecological sustainability of the species and alternative management protocols are needed for conservation of the species.     

Proline and Glutamine Improve in vitro Callus Induction and Subsequent Shooting in Rice

This study was conducted to evaluate the effects of proline and glutamine on in vitro callus induction and subsequent regeneration and to develop a reproducible and highly efficient plant regeneration protocol in four rice genotypes, viz. Pawana, Jaya, Indrayani and Ambemohar. Considerable variation in response to plant growth regulators and amino acid supplements used was observed in all the four genotypes. Medium supplemented with proline and glutamine was shown to be superior to medium without proline and glutamine. The best callusing from mature embryo was observed on Murashige and Skoog(MS) medium supplemented with 2.0 mg/L 2,4-dichlorophenoxyacetic acid(2,4-D), 500 mg/L proline and 500 mg/L glutamine. Shoot induction was higher in the callus obtained from medium supplemented with 500 mg/L proline and 500 mg/L glutamine. The highest shoot regeneration frequency(83.2%) was observed on MS medium with 2.0 mg/L benzylaminopurine, 0.5 mg/L 1-naphthaleneacetic acid, 500 mg/L proline, and 500 mg/L glutamine in the callus obtained from MS medium supplemented with 2.0 mg/L 2,4-D, 500 mg/L proline and 500 mg/L glutamine. Among the four genotypes, Pawana has the highest regeneration efficiency(83.2%), whereas the regeneration efficiency of the rest three rice genotypes was in the range of 32.0% to 72.3%. This optimized regeneration protocol can be efficiently used for Agrobacterium mediated genetic transformation in rice.     

MytiLec,a Mussel R-Type Lectin,Interacts with Surface Glycan Gb3 on Burkitt’s Lymphoma Cells to Trigger Apoptosis through Multiple Pathways

MytiLec; a novel lectin isolated from the Mediterranean mussel (Mytilus galloprovincialis); shows strong binding affinity to globotriose (Gb3: Galα1-4Galβ1-4Glc). MytiLec revealed β-trefoil folding as also found in the ricin B-subunit type (R-type) lectin family, although the amino acid sequences were quite different. Classification of R-type lectin family members therefore needs to be based on conformation as well as on primary structure. MytiLec specifically killed Burkitt''s lymphoma Ramos cells, which express Gb3. Fluorescein-labeling assay revealed that MytiLec was incorporated inside the cells. MytiLec treatment of Ramos cells resulted in activation of both classical MAPK/ extracellular signal-regulated kinase and extracellular signal-regulated kinase (MEK-ERK) and stress-activated (p38 kinase and JNK) Mitogen-activated protein kinases (MAPK) pathways. In the cells, MytiLec treatment triggered expression of tumor necrosis factor (TNF)-α (a ligand of death receptor-dependent apoptosis) and activation of mitochondria-controlling caspase-9 (initiator caspase) and caspase-3 (activator caspase). Experiments using the specific MEK inhibitor U0126 showed that MytiLec-induced phosphorylation of the MEK-ERK pathway up-regulated expression of the cyclin-dependent kinase inhibitor p21, leading to cell cycle arrest and TNF-α production. Activation of caspase-3 by MytiLec appeared to be regulated by multiple different pathways. Our findings, taken together, indicate that the novel R-type lectin MytiLec initiates programmed cell death of Burkitt’s lymphoma cells through multiple pathways (MAPK cascade, death receptor signaling; caspase activation) based on interaction of the lectin with Gb3-containing glycosphingolipid-enriched microdomains on the cell surface.