The effect of rhizobiophages on populations of Rhizobium trifolii in the root zone of clover plants

1980 ◽  
Vol 26 (5) ◽  
pp. 572-576 ◽  
Author(s):  
Yvonne M. Barnet
Keyword(s):  
Root Zone ◽  
Agar Medium ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Susceptible Strain ◽  
Rhizobium Trifolii ◽  
Single Strain

The effect of rhizobiophages CT3 and CT4 on Rhizobium trifolii SU91 and SU36, respectively, was examined. These phage-susceptible strains were used, either singly or paired with a competing phage-resistant type as inoculum for Trifolium subterraneum plants growing in vitro in agar medium. Addition of bacteriophage to single strain experiments produced no significant effects on total bacterial numbers, nodulation, or plant dry weight. However, when phages were added to the paired inocula, significant decreases in counts of the susceptible strain were observed, frequently accompanied by a rise in numbers of the resistant type. An increase in the proportion of ineffective variants of the susceptible rhizobia was also observed, although plant dry weights and nodule numbers were not altered. These effects were dependent only upon a difference in phage susceptibility of the bacteria and were obtained even when the competing strain was only partially resistant and a relatively poor competitor.

scholarly journals The Effect of pH Stress on the Survival of Rhizobium Trifolii and Sinorhizobium Meliloti in Vitro

2013 ◽  
Vol 70 (2) ◽  
pp. 449-450
Author(s):  
Monica NISTE ◽  
Roxana VIDICAN ◽  
Ioan ROTAR ◽  
Rodica POP
Keyword(s):  
Sinorhizobium Meliloti ◽  
Agar Medium ◽  
Rhizobium Trifolii ◽  
Ph Values ◽  
Optimum Ph ◽  
Yeast Extract Mannitol ◽  
Rhizobial Species ◽  
The Impact ◽  
Different Soils

Nitrogen-fixing symbiotic bacteria known as rhizobia can exist in different soils and adapt to different environmental conditions. The aim of this study was to determine the impact of pH on the growth of Rhizobium trifolii and Sinorhizobium meliloti. Rhizobial species were isolated using yeast extract mannitol agar medium) in which the pH values were adjusted to 5.0, 6.0, 8.0 and 9.0 by adding HCl and NaOH. The optimum pH for rhizobia is neutral or slightly alkaline (pH 8) and they are more sensitive to acidity. Sinorhizobium meliloti developed better in an acid medium compared to Rhizobium trifolii.

The in vitro inhibition of Phytophthora clandestina by some rhizobia and the possible role of Rhizobium trifolii in biological control of Phytophthora root rot of subterranean clover

1999 ◽  
Vol 50 (8) ◽  
pp. 1469 ◽  
Author(s):  
S. Simpfendorfer ◽  
T. J. Harden ◽  
G. M. Murray
Keyword(s):  
Biological Control ◽  
Root Rot ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Root Disease ◽  
Rhizobium Trifolii ◽  
Biological Control Agents ◽  
Control Activity ◽  
Phytophthora Root Rot

The interaction between 29 isolates of Rhizobium and the in vitro growth of 3 strains of Phytophthora clandestina was investigated to determine the potential of these bacteria as biological control agents against root rot of subterranean clover (Trifolium subterraneum L.). The biological control activity of Rhizobium on the severity of root disease in seedlings was also investigated under glasshouse conditions. Thirteen of the 29 Rhizobium isolates caused significant reductions in the hyphal growth of the 3 P. clandestina isolates examined. Inoculation of seedlings with Rhizobium trifolii reduced the severity of root disease by 14–58% with corresponding increases in dry matter production of 20–73%. These results indicate that Rhizobium species have potential as biological control agents against the root rot of T. subterraneum seedlings caused by P. clandestina.

Rhizosphere relationships of subterranean clover. I. Interactions between strains of Rhizobium trifolii.

1954 ◽  
Vol 5 (2) ◽  
pp. 247 ◽  
Author(s):  
JR Harris
Keyword(s):  
Nitrogen Fixation ◽  
Host Plant ◽  
Root Zone ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Rhizobium Trifolii ◽  
Rhizobial Strain ◽  
Susceptible Host ◽  
Active Elements ◽  
Indigenous Microflora

A study was made of a number of effective and ineffective strains of Rhizobium trifolii in association with subterranean clover (Trifolium subterraneum L.), variety Bacchus Marsh. Where these were inoculated singly into sterilized soils in pot experiments conducted in the greenhouse, typical effective, ineffective, or intermediate plant reactions were obtained. Where more than one strain was inoculated, competition between strains took place and was reflected in nodule pattern and plant reaction. Some strains consistently failed to produce appreciable nodules in the presence of other rhizobia, some showed modification to varying degrees, and some were unaffected. Such behaviour was found to be closely linked with the ability of the strain to proliferate in the rhizosphere of the host plant, and placement of inoculum was shown to influence plant reaction. The concept of "incursion" as a property of a rhizobial strain is suggested. An incursive strain is one able to migrate from the initial site of inoculation and establish an adequate population in the root zone of the susceptible host despite the presence of active elements of the indigenous microflora and microfauna, including antagonistic and predatory forms. The property of incursion is independent of considerations of efficiency of nitrogen fixation or virulence for the host plant. Strains of rhizobia which are poorly incursive may fail to infect the host upon which they have been inoculated if subject to competition from indigenous rhizobia already established in the soil. The necessity of assessing properties of virulence and incursion as well as efficiency of nitrogen fixation in selecting rhizobia for purposes of commercial inoculation is stressed, and the methods of making such tests are discussed.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation. V. Effect of Time of Exposure to Unfavourable Root Temperatures

1967 ◽  
Vol 20 (6) ◽  
pp. 1105 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Symbiotic Nitrogen Fixation ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Rhizobium Trifolii ◽  
Optimal Temperature ◽  
Three Stages

Symbiotic nitrogen fixation by Trifolium subterraneum L., inoculated with three strains of Rhizobium trifolii Dang., was examined over the range of root temperatures 8-28�0. The plants were transferred from an optimal temperature for nitrogen fixation (23�0) to other temperatures at three stages, namely (1) immediately after inoculation, 3 days after germination, (2) 14 days after germ� ination, when nitrogen fixation had commenced, and (3) 21 days after germination, when the plants had been fixing nitrogen for at least 7 days. Nitrogen increase and dry weight accumulation were determined for two growth periods-days 14-21 (I) and days 21-28 (II)

Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

2020 ◽  
Vol 13 (2) ◽  
pp. 54-65 ◽  
Author(s):  
M.E.A. Bendaha ◽  
H.A. Belaouni
Keyword(s):  
Root Length ◽  
Biocontrol Agent ◽  
Growth Promotion ◽  
Dry Weight ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Plant Growth Promoting ◽  
Enterobacter Ludwigii ◽  
Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

scholarly journals Evaluation of the Antioxidant, Anti-Inflammatory and Cytoprotective Activities of Halophyte Extracts against Mycotoxin Intoxication

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 312
Author(s):  
Nolwenn Hymery ◽  
Xavier Dauvergne ◽  
Halima Boussaden ◽  
Stéphane Cérantola ◽  
Dorothée Faugère ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Protective Action ◽  
Dry Weight ◽  
Cell Protection ◽  
Natural Habitats ◽  
Total Antioxidant ◽  
Mdbk Cells ◽  
Dpph Scavenging ◽  
T2 Toxin

Twelve halophyte species belonging to different families, widely represented along French Atlantic shoreline and commonly used in traditional medicine, were screened for protective activities against mycotoxins, in order to set out new promising sources of natural ingredients for feed applications. Selected halophytic species from diverse natural habitats were examined for their in vitro anti-mycotoxin activities, through viability evaluation of Madin-Darby Bovine Kidney (MDBK) and intestinal porcine enterocyte (IPEC-J2) cell lines. Besides, the in vitro antioxidant activities of plant extracts were assessed (total antioxidant and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging bioassays). Of the 12 species, Galium arenarium, Convolvulus soldanella and Eryngium campestre exhibited the most protective action on MDBK and IPEC-J2 cells against zearalenone (ZEN) or T2 toxin contamination (restoring about 75% of cell viability at 10 μg·mL−1) without inflammation response. They also had strong antioxidant capacities (Inhibitory concentration of 50% (IC50) < 100 μg·mL−1 for DPPH radical and total antioxidant capacity (TAC) of 100 to 200 mg Ascorbic Acid Equivalent (AAE)·g−1 Dry Weight), suggesting that cell protection against intoxication involves antioxidant action. A bio-guided study showed that fractions of G. arenarium extract protect MDBK cells against T2 or ZEN toxicity and several major compounds like chlorogenic acid and asperuloside could be involved in this protective effect. Overall, our results show that the halophytes G. arenarium, C. soldanella and E. campestre should be considered further as new sources of ingredients for livestock feed with protective action against mycotoxin intoxication.

scholarly journals In-Vitro Evaluation of the Antioxidant and Anti-Inflammatory Activity of Volatile Compounds and Minerals in Five Different Onion Varieties

Separations ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 57
Author(s):  
Rokayya Sami ◽  
Abeer Elhakem ◽  
Mona Alharbi ◽  
Manal Almatrafi ◽  
Nada Benajiba ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Dimethyl Sulfide ◽  
Antioxidant Activities ◽  
Dry Weight ◽  
No Production ◽  
Oxidative Stresses ◽  
Anti Inflammatory ◽  
Red Variety ◽  
A Minor

Onions contain high antioxidants compounds that fight inflammation against many diseases. The purpose was to investigate some selected bioactive activities of onion varieties (Yellow, Red, Green, Leek, and Baby). Antioxidant assays and anti-inflammatory activities such as NO production with the addition of some bioactive components were determined and analyzed by using a spectrophotometer. Gas chromatography and mass spectrometry (GC–MS) was used for the volatile compounds, while an Atomic absorption spectrometer was used for mineral determinations. Red variety achieved the highest antioxidant activities. The total flavonoids were between (12.56 and 353.53 mg Quercetin/gin dry weight) (dw) and the total phenol was (8.75–25.73 mg/g dw). Leek, Yellow and Green extracts achieved highly anti-inflammatory values (3.71–4.01 μg/mL) followed by Red and Baby extracts, respectively. The highest contents of sodium, potassium, zinc, and calcium were established for Red onions. Furfuraldehyde, 5-Methyl-2-furfuraldehyde, 2-Methyl-2-pentenal, and 1-Propanethiol were the most predominant, followed by a minor abundance of the other compounds such as Dimethyl sulfide, Methyl allyl disulfide, Methyl-trans-propenyl-disulfide, and Methyl propyl disulfide. The results recommend that these varieties could act as sources of essential antioxidants and anti-inflammatories to decrease inflammation and oxidative stresses, especially red onions that recorded high activities.

scholarly journals Dampak Dosis Kompos Kotoran Sapi Terhadap Profil Suhu Tanah di Zona Perakaran dan Produktivitas Tanaman Pakcoy (Brassica rafa L)

2019 ◽  
Vol 7 (2) ◽  
pp. 253
Author(s):  
I Made Andi Purnama Wijaya ◽  
Yohanes Setiyo ◽  
I Wayan Tika
Keyword(s):  
Physical Properties ◽  
Root Zone ◽  
Treatment Plant ◽  
Dry Weight ◽  
Fertilizer Application ◽  
Water Levels ◽  
Optimum Dose ◽  
Root Zone Temperature ◽  
Rooting Zone ◽  
Treatment Dose

Suhu tanah adalah salah satu sifat fisik tanah yang secara langsung mempengaruhi pertumbuhan tanaman pakcoy. Tujuan penelitian ini adalah (1) untuk menganalisis suhu di zona perakaran, (2) menganalisis hubungan antara dosis pemupukan mempergunakan kompos dengan suhu di zona perakaran dan (3) untuk menganalis suhu yang optimum untuk produktivitas dan kualitas pakcoy yang dihasilkan saat panen. Rancangan penelitian yang digunakan rancangan acak lengkap, dengan lima perlakuan dan tiga ulangan. Perlakuan tersebut adalah P0 : dosis kompos 0 kg/m2, P1 : dosis kompos 1 kg/m2, P2 : dosis kompos 2 kg/m2, P3 : dosis kompos 3 kg/m2, dan P4 : dosis kompos 4 kg/m2. Parameter yang diamati pada penelitian ini adalah suhu udara, suhulingkungan, kadar air tanah dan produktivitas. Padamalam hari suhu tanah di zona perakaran lebih tinggi 0,59 oC dari pada suhu lingkungan. Suhu tanah di zona perakaran terendah dan tertinggi adalah 18,02 oC dan 21,94 oC. Suhu tanah malam hari dan siang hari untuk dosis 0-5kg/m2 masih toleran pada tanaman pacoy. Berat kering tanaman pakcoy tertinggi pada perlakuan dosis kompos 4kg/m2 denganberat 92,21 gram/tanaman dan terendah pada perlakuan kontrol dengan berat 71,82 gram/tanaman.   The temperature of the soil is one of the physical properties of the soil, this soil physical properties direc2tly affect plant growth pakcoy.  The purpose of this research are (1) to analyze the temperature at root zone, temperature inside and out of the mini greenhouse, (2) analyze the relationship between temperature at root zone  with doses of compost fertilizer application and 3) to analyze the optimum dose of compost based on productivity and quality of the pakcoy is generated when the harvest. The design of the research used randomized complete design, with five treatments and three replicates. The treatment is P0: a dose of compost 0 kg/m, P1: a dose of compost 1 kg/m2, P2: a dose of compost 2 kg/m2, P3: the dose of compost 3 kg/m2, and P4: a dose of compost 4 kg/m2. The parameters observed in this research is the air temperature, the temperature of the environment, ground water levels and productivity.  At night the temperature of the soil rooting zone higher at 0.59 ºC than at the temperature of the environment. Soil temperature at root zone the lowest  and the highest  are 18.02 oC and 21.94 oC.  The temperature of the soil the night and during the day for dose 0-5 kg/m2 was still tolerant plants pakcoy. Dry weight of the plant the highest pakcoy on the treatment dose of compost 4 kg/m2  with a weight of 92.21 grams/lowest at the treatment plant and the control by the weight of 71.82 grams/plant.

376 A phase I/II study of live biotherapeutic MRx0518 in combination with pembrolizumab in patients refractory to immune checkpoint inhibitors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A401-A401
Author(s):  
Shubham Pant ◽  
Amishi Shah ◽  
Pavlos Msaouel ◽  
Matthew Campbell ◽  
Shi-Ming Tu ◽  
...  
Keyword(s):  
Phase I ◽  
Disease Progression ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Tumour Response ◽  
Checkpoint Inhibition ◽  
Single Strain

BackgroundMRx0518 is a novel, human gut microbiome-derived, single-strain, oral live biotherapeutic. It is a bacterium of the Enterococcus genus that was selected for development in the treatment of solid tumours for its strong in vitro and in vivo immunostimulatory activity. In vivo studies have shown that MRx0518 can inhibit tumour growth in different syngeneic cancer models as monotherapy and in combination with checkpoint inhibitors. MRx0518 has been shown to reduce Treg and increase Th1 and Tc1 lymphocyte differentiation in vitro, and increase intratumoral CD4+ and CD8+ T cells and NK cells in vivo.This phase I/II clinical study is evaluating the combination of MRx0518 and pembrolizumab in a cohort of heavily pre-treated patients refractory to immune checkpoint inhibitors (ICIs) to assess whether it is safe and can provide a clinical benefit.MethodsThe study is being conducted in two parts. Part A is complete and evaluated safety of the combination therapy in a cohort of 12 mRCC and mNSCLC patients. This data was assessed by the Safety Review Committee and it was determined appropriate to proceed to Part B. Part B is now recruiting up to 30 additional patients per indication (RCC, NSCLC or bladder cancer) at several US sites. Patients in both parts must be refractory to checkpoint inhibition. This is defined as having had an initial benefit from PD-1 pathway targeting immune checkpoint inhibition (ICI) but developing disease progression confirmed by two radiological scans ≥4 weeks apart in the absence of rapid clinical progression and within 12 weeks of last dose of ICI. Patients are treated with 1 capsule of MRx0518 (1 × 1010 to 1 × 1011 CFU) twice daily and pembrolizumab (200 mg every 3 weeks) for up to 35 cycles or until disease progression. Tumour response is assessed every 9 weeks per RECIST. Blood, stool and urine samples are collected throughout the study to evaluate immune markers and microbiome. Patients may choose to consent to tissue biopsies. The primary objective of the study is to evaluate safety of the combination by monitoring toxicities in the first cycle of treatment. Secondary objectives are to evaluate efficacy via ORR, DOR, DCR (CR, PR or SD ≥6 months) and PFS. Exploratory objectives are to evaluate biomarkers of treatment effect, impact on microbiota and OS and correlation of clinical outcome with PD-L1 CPS/TPS.ResultsN/AConclusionsN/ATrial RegistrationNCT03637803Ethics ApprovalThis study was approved by University of Texas MD Anderson’s Institutional Review Board; approval ref. 2018-0290

scholarly journals Co-Microencapsulated Black Rice Anthocyanins and Lactic Acid Bacteria: Evidence on Powders Profile and In Vitro Digestion

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2579
Author(s):  
Carmen-Alina Bolea ◽  
Mihaela Cotârleț ◽  
Elena Enachi ◽  
Vasilica Barbu ◽  
Nicoleta Stănciuc
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Oryza Sativa L ◽  
Milk Proteins ◽  
Ethanolic Extract ◽  
Dry Weight ◽  
Hot Water ◽  
Raw Material ◽  
Black Rice

Two multi-functional powders, in terms of anthocyanins from black rice (Oryza sativa L.) and lactic acid bacteria (Lactobacillus paracasei, L. casei 431®) were obtained through co-microencapsulation into a biopolymer matrix composed of milk proteins and inulin. Two extracts were obtained using black rice flour as a raw material and hot water and ethanol as solvents. Both powders (called P1 for aqueous extract and P2 for ethanolic extract) proved to be rich sources of valuable bioactives, with microencapsulation efficiency up to 80%, both for anthocyanins and lactic acid bacteria. A higher content of anthocyanins was found in P1, of 102.91 ± 1.83 mg cyanindin-3-O-glucoside (C3G)/g dry weight (DW) when compared with only 27.60 ± 17.36 mg C3G/g DW in P2. The morphological analysis revealed the presence of large, thin, and fragile structures, with different sizes. A different pattern of gastric digestion was observed, with a highly protective effect of the matrix in P1 and a maximum decrease in anthocyanins of approximatively 44% in P2. In intestinal juice, the anthocyanins decreased significantly in P2, reaching a maximum of 97% at the end of digestion; whereas in P1, more than 45% from the initial anthocyanins content remained in the microparticles. Overall, the short-term storage stability test revealed a release of bioactive from P2 and a decrease in P1. The viable cells of lactic acid bacteria after 21 days of storage reached 7 log colony forming units (CFU)/g DW.

Sign in / Sign up

Export Citation Format

Share Document