INHIBITION OF RESPIRATION, GERMINATION, AND GROWTH BY SUBSTANCES ARISING DURING THE DECOMPOSITION OF CERTAIN PLANT RESIDUES IN THE SOIL

1958 ◽  
Vol 36 (5) ◽  
pp. 621-647 ◽  
Author(s):  
Z. A. Patrick ◽  
L. W. Koch
Keyword(s):  
Plant Residues ◽  
Toxic Substances ◽  
Root Cells ◽  
Toxic Activity ◽  
Root Rots ◽  
High Soil Moisture ◽  
Heat Stable ◽  
Tobacco Seedlings ◽  
Ph Range ◽  
Germination And Growth

Substances capable of markedly inhibiting the respiration, germination, and growth of tobacco seedlings were obtained after residues from timothy, corn, rye, or tobacco plants had been allowed to decompose under appropriate conditions in the soil. Bio-assay tests, based on manometric methods, made it possible to determine some of the conditions under which the decomposition gave rise to phytotoxic by-products and to obtain rapidly an accurate measure of the degree of their toxicity. Among the factors influencing the production of the toxic products, the species and stage of maturity of plant material added, the water content and pH of the soil, and length of decomposition period seemed most important. Substances capable of reducing the respiration of tobacco seedlings by 50 to 90% were consistently obtained when any of the abovementioned plant residues had been decomposing for 15 to 25 days under conditions of high soil moisture and when the pH of the soil solution was below 5.5 throughout this period. Timothy gave rise to substances possessing the highest toxic activity, followed by corn, then rye, and finally tobacco. Aqueous extracts of unamended soil or of macerated plant tissues prepared either before decomposition had taken place or when decomposition was inhibited by autoclaving the soil were not toxic.The toxic substances, obtained by water extraction, exhibited an inhibiting effect on respiration of tobacco seedlings after an exposure of less than one hour and also induced darkening and necrosis of root cells. Some extracts affected the cells of the apical meristem most severely while others affected only the cells of the elongation region.While the toxic substances have not been identified, they were relatively nonspecific in their action, affecting tobacco, timothy, and barley in approximately the same manner and in many instances possessed also antifungal activity. They were soluble in water, insoluble in petroleum ether, stable in acid, and most active in the pH range 4.5 to 5.8. They were precipitated by alkali and the activity was markedly reduced when readjusted to the acid range. They were also heat stable and did not lose their activity in storage at 1°–3 °C. provided they were covered by a layer of toluene.Because of their rapid production and the marked injurious effects exerted on various plants it is believed that these toxins may perform a significant role in the field as the primary cause of some root rots and in predisposing plants to attack by organisms not normally regarded as pathogenic.

Isolation and some properties of extracellular heat-stable lipases fromPseudomonas fluorescensstrain AFT 36

1983 ◽  
Vol 50 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Patrick F. Fox ◽  
Leszek Stepaniak
Keyword(s):  
Phosphate Buffer ◽  
Lipolytic Activity ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Lipase Production ◽  
Maximum Activity ◽  
Temperature Range ◽  
Milk Serum ◽  
Heat Stable ◽  
Ph Range

SummaryAeration increased the growth and lipase production in milk byPseudomonas fluorescensstrain AFT 36, isolated from refrigerated bulk milk. A heat-stable lipase was isolated from a shaken milk culture of this microorganism by DEAE-chromatography and gel filtration in Sepharose 6B. The lipase-rich fraction from DEAE cellulose contained 3 lipases that were separated by gel filtration; only the principal lipase, which represented ∼ 71 % of total lipolytic activity, was characterized. The purified enzyme showed maximum activity on tributyrin at pH 8·0 and 35 °C; it had aKmon tributyrin of 3·65 mM. and was inhibited by concentrations of substrate > ∼ 17 mM. The enzyme was very stable over the pH range 6–9; it was relatively heat-labile in phosphate buffer in the temperature range 60–80 °C, where it was stabilized significantly by Ca2+. It was, however, very stable at 100–150 °C: theDvalues at 150 °C were ∼ 22 s and 28 s in phosphate buffer and synthetic milk serum respectively; the correspondingZvalues in the temperature range 100–150 °C were ∼ 40 and ∼ 42 °C and theEafor inactivation were 7·65 × 104J mol-1and 6·97 × 104J mol-1respectively.

scholarly journals Allelopathy of Knotweeds as Invasive Plants

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Hisashi Kato-Noguchi
Keyword(s):  
Plant Species ◽  
Mycorrhizal Fungi ◽  
Invasive Plant ◽  
Native Plants ◽  
Rhizosphere Soil ◽  
Arbuscular Mycorrhizal ◽  
Plant Residues ◽  
Japanese Knotweed ◽  
Plant Parts ◽  
Germination And Growth

Perennial herbaceous Fallopia is native to East Asia, and was introduced to Europe and North America in the 19th century as an ornamental plant. Fallopia has been spreading quickly and has naturalized in many countries. It is listed in the world’s 100 worst alien species. Fallopia often forms dense monospecies stands through the interruption of the regeneration process of indigenous plant species. Allelopathy of Japanese knotweed (Fallopia japonica), giant knotweed (Fallopia sachalinensis), and Bohemian knotweed (Fallopia x bohemica) has been reported to play an essential role in its invasion. The exudate from their roots and/or rhizomes, and their plant residues inhibited the germination and growth of some other plant species. These knotweeds, which are non-mycorrhizal plants, also suppressed the abundance and species richness of arbuscular mycorrhizal fungi (AMF) in the rhizosphere soil. Such suppression was critical for most territorial plants to form the mutualism with AMF, which enhances the nutrient and water uptake, and the tolerance against pathogens and stress conditions. Several allelochemicals such as flavanols, stilbenes, and quinones were identified in the extracts, residues, and rhizosphere soil of the knotweeds. The accumulated evidence suggests that some of those allelochemicals in knotweeds may be released into the rhizosphere soil through the decomposition process of their plant parts, and the exudation from their rhizomes and roots. Those allelochemicals may inhibit the germination and growth of native plants, and suppress the mycorrhizal colonization of native plants, which provides the knotweeds with a competitive advantage, and interrupts the regeneration processes of native plants. Therefore, allelopathy of knotweeds may contribute to establishing their new habitats in the introduced ranges as invasive plant species. It is the first review article focusing on the allelopathy of knotweeds.

Haemophilus paragallinarumsecretes metalloproteases

2005 ◽  
Vol 51 (10) ◽  
pp. 893-896 ◽  
Author(s):  
P C Rivero-García ◽  
C Vázquez Cruz ◽  
P Sánchez Alonso ◽  
S Vaca ◽  
E Negrete-Abascal
Keyword(s):  
Molecular Mass ◽  
Proteolytic Activity ◽  
Culture Media ◽  
High Molecular Mass ◽  
Secreted Proteins ◽  
Extracellular Proteases ◽  
Heat Stable ◽  
Infectious Coryza ◽  
Ph Range ◽  
Polyclonal Serum

Haemophilus paragallinarum secretes metalloproteases into different culture media lacking serum. Secreted proteins, concentrated by precipitation with 70% ammonium sulphate ((NH4)2SO4) or methanol, displayed proteolytic activity at >100 kDa molecular mass in 10% polyacrylamide gels co-polymerized with porcine gelatin (0.1%). They were active in a broad pH range (4–9); pH 7.5 being the optimum. Protease activity was inhibited by 20 mmol EDTA/L and reactivated by calcium. The proteolytic activity was heat-stable at 40, 50, and 60 °C, but its activity diminished at 70 °C or higher. Secreted proteins partially degraded chicken immunoglobulin G (IgG) and cross-reacted with a polyclonal serum against a high molecular mass protease secreted by Actinobacillus pleuropneumoniae. Extracellular proteases could play a role in infectious coryza caused by H. paragallinarum.Key words: pathogenicity, secreted protein, infectious coryza.

Clinical significance and partial biochemical characterization of lactate dehydrogenase isoenzyme 6.

1984 ◽  
Vol 30 (1) ◽  
pp. 46-49 ◽  
Author(s):  
C H Ketchum ◽  
C A Robinson ◽  
L M Hall ◽  
W E Grizzle ◽  
N K Maclaren ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Lactate Dehydrogenase ◽  
Biochemical Characterization ◽  
Serum Lactate ◽  
Serum Lactate Dehydrogenase ◽  
Tissue Samples ◽  
Heat Stable ◽  
Autopsy Tissues ◽  
Ph Range ◽  
Clinical Conditions

Abstract We report nine patients with a sixth band, migrating cathodic to lactate dehydrogenase 5, appearing on routine electrophoresis for serum lactate dehydrogenase (LD, EC 1.1.1.27). Eight of these patients died during their hospitalization. Acidosis, hypotension, and sepsis were the common clinical conditions preceding the band's appearance. In several cases the band appeared transiently. We examined tissue samples from two of the cases, finding LD-6 in liver and skeletal muscle but not in heart. In randomly selected autopsy tissues, LD-6 was detected consistently in liver and skeletal muscle, sometimes in spleen, kidney, and adrenal tissue, but never in heart. Biochemical studies indicate that the LD-6 isoenzyme is not an artifact or an immunoglobulin complex, is larger than the other LD isoenzymes, contains an M-subunit but not an H-subunit, has an isoelectric point in the pH range of 9.0-9.6, and is more heat stable than LD-5.

scholarly journals Involvement of Allelopathy in the Invasive Potential of Tithonia diversifolia

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 766 ◽  
Author(s):  
Hisashi Kato-Noguchi
Keyword(s):  
Root Exudates ◽  
Competitive Ability ◽  
Invasive Plant ◽  
Sesquiterpene Lactones ◽  
Plant Residues ◽  
Tithonia Diversifolia ◽  
Native Plant ◽  
Invasive Potential ◽  
Living Tissues ◽  
Germination And Growth

Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) is native to Mexico and Central America. The species is spreading quickly and has naturalized in more than 70 countries. It has often been recorded as a harmful invasive plant that disturbs native plant communities. Phytotoxic chemical interactions such as allelopathy between invasive plants and native plants have been reported to play an important role in the invasion. Evidence for allelopathy of T. diversifolia has accumulated in the literature over 30 years. Thus, the objective of this review was to discuss the possible involvement of allelopathy in the invasive potential of T. diversifolia. The extracts, root exudates, and plant residues of T. diversifolia inhibited the germination and growth of other plant species. The soil water and soil collected from T. diversifolia fields also showed inhibitory growth effects. The decomposition rate of T. diversifolia residues in soil was reported to be high. Phytotoxic substances such as sesquiterpene lactones were isolated and identified in the extracts of T. diversifolia. Some phytotoxic substances in T. diversifolia may be released into the soil through the decomposition of the plant residues and the exudation from living tissues of T. diversifolia, including its root exudates, which act as allelopathic substances. Those allelopathic substances can inhibit the germination and growth of neighboring plants and may enhance the competitive ability of the plants, make them invasive.

WATER-SOLUBLE SUBSTANCES IN DEAD BRANCHES OF ASPEN (POPULUS TREMULOIDES MICHX.) AND THEIR EFFECTS ON FOMES IGNIARIUS

1964 ◽  
Vol 42 (8) ◽  
pp. 969-977 ◽  
Author(s):  
R. E. Wall ◽  
J. E. Kuntz
Keyword(s):  
Cross Section ◽  
Populus Tremuloides ◽  
Mycelial Growth ◽  
Cold Water ◽  
Water Soluble ◽  
Water Extracts ◽  
Heat Stable ◽  
Dead Branch ◽  
Inhibitory Components ◽  
Germination And Growth

Cold-water extracts from the basal portions of dead branches of trembling aspen markedly stimulated basidiospore germination and mycelial growth of Fomes igniarius var. populinus at concentrations which inhibited spore germination and growth of other varieties of F. igniarius. Water extracts which caused these differential effects could not be obtained from living aspen branches. Selective effects in favor of F. igniarius var. populinus were characteristic of extracts from the surface tissues of branch stubs, as well as from the total cross section, except that surface extracts were less fungistatic and were not found in branches in all stages of deterioration. Extracts from the axillary regions of dead branches were more fungistatic than those from more distal parts. The stimulatory and inhibitory components of dead branch extracts were heat stable and partially soluble in organic solvents.

Novel bacteriocins produced by Geobacillus stearothermophilus

2009 ◽  
Vol 4 (2) ◽  
pp. 196-203 ◽  
Author(s):  
Karina Pokusaeva ◽  
Nomeda Kuisiene ◽  
Dziuginta Jasinskyte ◽  
Kazimiera Rutiene ◽  
Jordana Saleikiene ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Direct Detection ◽  
Proteolytic Enzymes ◽  
Geobacillus Stearothermophilus ◽  
Inhibitory Peptides ◽  
Heat Stable ◽  
Sds Page ◽  
Ph Range ◽  
Agriculture And Food ◽  
Logarithmic Growth

AbstractFour novel heat-stable bacteriocin-like substances were found to be produced by Geobacillus stearothermophilus strains isolated from oil-wells in Lithuania. Geobacillus stearothermophilus 32A, 17, 30 and 31 strains were identified as producers of bacteriocins with bactericidal activity against closely related Geobacillus species and several pathogenic strains: Bacillus cereus DSM 12001 and Staphylococcus haemolyticus P903. The secretion of the analysed bacteriocins started during early logarithmic growth and dropped sharply after the culture entered the stationary phase of growth. The antimicrobial activity of the bacteriocins against sensitive indicator cells disappeared after treatment with proteolytic enzymes, indicating their proteinaceous nature. Bacteriocins were stable throughout the pH range between 4 and 10, and no loss in activity was noted following temperature exposures up to 100°C. Direct detection of antibacterial activity on SDS-PAGE suggests that the inhibitory peptides have a molecular weight of 6–7.5 kDa. Such bacteriocins with broad activity spectra, including antipathogenic action, are attractive to the biotechnology industry as they could be used as antimicrobial agents in medicine, agriculture and food products.

scholarly journals A Novel Bacteriocin From Lactobacillus Pentosus ZFM94 and Its Antibacterial Mode of Action

2021 ◽  
Vol 8 ◽  
Author(s):  
Mengdi Dai ◽  
Yanran Li ◽  
Luyao Xu ◽  
Danli Wu ◽  
Qingqing Zhou ◽  
...  
Keyword(s):  
High Performance ◽  
Micrococcus Luteus ◽  
Gel Chromatography ◽  
Lactobacillus Pentosus ◽  
Minimal Inhibitory Concentrations ◽  
Flight Mass Spectrometry ◽  
Lipid Ii ◽  
Heat Stable ◽  
Wide Ph Range ◽  
Ph Range

Bacteriocins are bioactive antimicrobial peptides synthesized in the ribosome of numerous bacteria and released extracellularly. Pentocin ZFM94 produced by Lactobacillus pentosus (L. pentosus) ZFM94, isolated from infant feces with strong antibacterial activity, was purified by ammonium sulfate precipitation, dextran gel chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The molecular mass of the purified bacteriocin was 3,547.74 Da determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Pentocin ZFM94 exhibited broad-spectrum antimicrobial activity against tested Gram-positive and Gram-negative bacteria, and the minimal inhibitory concentrations (MICs) of Micrococcus luteus (M. luteus) 10,209, Staphylococcus aureus (S. aureus) D48, and Escherichia coli (E. coli) DH5α were 1.75, 2.00, and 2.50 μm, respectively. Pentocin ZFM94 was heat-stable (30 min at 80°C) and showed inhibitory activity over a wide pH range (5.00–7.00). It could be degraded by trypsin and pepsin, but not by amylase, lysozyme, lipase, and ribonuclease A. Fluorescence leakage assay showed that pentocin ZFM94 induced disruption of the cell membrane and caused leakage of cellular content. Furthermore, lipid II was not an antibacterial target of pentocin ZFM94. This study laid the foundation for further development and utilization of L. pentosus ZFM94 and its bacteriocin.

scholarly journals The measurement of plant residues distribution quality after harvest by conventional and axial combine harvesters

2011 ◽  
Vol 51 (No. 6) ◽  
pp. 249-254 ◽  
Author(s):  
F. Kumhála ◽  
Z. Kvíz ◽  
J. Mašek ◽  
P. Procházka
Keyword(s):  
Feed Rate ◽  
Quality Evaluation ◽  
Quality Measurement ◽  
Point Of View ◽  
Plant Residues ◽  
Small Particles ◽  
Operational Conditions ◽  
Combine Harvesters ◽  
Germination And Growth ◽  
Plant Germination

This paper concerns the evaluation of the husk and straw distribution quality measurement on different commonly used combine harvesters. The plant residues can significantly influence the next plant germination and growth, especially when they are unevenly placed on the field surface. The experiments were realised during the harvesting season in years 2001, 2002 and 2003. All machines were evaluated under normal operational conditions by winter wheat and oil rape harvest. For plant residues distribution quality evaluation the Christiansen’s coefficient was calculated. The most important outcome from the measurement is that the distribution pattern of husk and straw depends on instantaneous material feed rate through the harvester. The higher material feed rate the worse regularity of husk and straw distribution. Axial combine harvesters break up straw more intensively then tangential combine harvesters. Straw crushers on tangential combine harvesters are therefore more loaded and need more attention from the crushing and distribution quality point of view. On the contrary, on axial combine harvesters most material goes on cleaning sieves and more attention should be paid to this small particles distribution.

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