scholarly journals Effectiveness of Augmentative Biological Control of Streptomyces griseorubens UAE2 Depends on 1-Aminocyclopropane-1-Carboxylic Acid Deaminase Activity against Neoscytalidium dimidiatum

2021 ◽  
Vol 7 (11) ◽  
pp. 885
Author(s):  
Bader M. Al Hamad ◽  
Seham M. Al Raish ◽  
Gaber A. Ramadan ◽  
Esam Eldin Saeed ◽  
Shaikha S. A. Alameri ◽  
...  
Keyword(s):  
Biological Control ◽  
Acc Deaminase ◽  
Stem Canker ◽  
Complete Suppression ◽  
Cell Wall Degrading Enzymes ◽  
Antifungal Metabolites ◽  
Neoscytalidium Dimidiatum ◽  
Streptomyces Griseorubens

To manage stem canker disease on royal poinciana, actinobacterial isolates were used as biological control agents (BCAs) based on their strong in vitro inhibitory effects against Neoscytalidium dimidiatum. Streptomyces griseorubens UAE2 and Streptomyces wuyuanensis UAE1 had the ability to produce antifungal compounds and cell-wall-degrading enzymes (CWDEs). Only S. griseorubens, however, restored the activity of 1-aminocyclopropane-1-carboxylate (ACC) deaminase (ACCD). In vivo apple fruit bioassay showed that lesion development was successfully constrained by either isolates on fruits inoculated with N. dimidiatum. In our greenhouse and container nursery experiments, S. griseorubens showed almost complete suppression of disease symptoms. This was evident when the preventive treatment of S. griseorubens significantly (p < 0.05) reduced the numbers of conidia of N. dimidiatum and defoliated leaves of royal poinciana seedlings to lesser levels than when S. wuyuanensis was applied, but comparable to control treatments (no pathogen). The disease management of stem canker was also associated with significant (p < 0.05) decreases in ACC levels in royal poinciana stems when S. griseorubens was applied compared to the non-ACCD-producing S. wuyuanensis. This study is the first to report the superiority of antagonistic actinobacteria to enhance their effectiveness as BCAs not only for producing antifungal metabolites and CWDEs but also for secreting ACCD.

Virulence and Genetic Characterization of Six Baculovirus Strains Isolated From Different Populations of Spodoptera Frugiperda (Lepidoptera: Noctuidae)

2021 ◽  
Author(s):  
Ingrid Zanella-Saenz ◽  
Elisabeth A. Herniou ◽  
Jorge E. Ibarra ◽  
Ma.Cristina Del Rincón-Castro ◽  
Ilse Alejandra Huerta-Arredondo
Keyword(s):  
Biological Control ◽  
Cell Cultures ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
The United States ◽  
Infection Mechanisms ◽  
Different Populations

Abstract Fall armyworm (FAW), Spodoptera frugiperda (Smith, 1797), is a polyphagous, voracious, and economically important agricultural pest. Biological control of FAW is a strategy that must be further explored. This study evaluated six baculovirus strains isolated from infected FAW larvae from Mexico, Argentina, Honduras, and the United States. Five alphabaculoviruses (SfNPV-An2, SfNPV-Arg, SfNPV-Fx, SfNPV-Ho and SfNPV-Sin) and one betabaculovirus (SfGV-RV), were tested against FAW larvae, showing a wide diversity of virulence levels among strains when their estimated LC50s were compared, being SfNPVArg, SfNPV-Ho and SfNPV-Fx more virulent than SfNPV-An 2 , SfNPV-Sin and SfGV-RV. To determine any virulence difference in vitro studies of these isolates, Sf9 cell cultures were used. Interestingly, only ODVs from four of the test SfNPV strains showed infectivity on Sf9 cell cultures, and some differences in virulence were observed. Genomic restriction analyses and partial sequences of lef-8, lef-9 , and polh/granulin genes showed little variability among alphabaculoviruses, both, among them and with previously reported sequences. However, sequences from SfGV-RV were closer to previously reported sequences from the SfGVVG008 strain than the SfGV-Arg and SfGV-VG014 strains. The great difference in the in vivo virulence was not correlated with great similarity among the isolates. The characterization of these six baculoviruses isolates offers the basis for exploring their potential as biological control agents against S. frugiperda, as well the initial studies on their specific infection mechanisms, evolution, and ecology.

scholarly journals In vitro and in vivo Assay for Assessment of the Biological Control Potential of Streptomyces sp. KT

2017 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Tatsuya Ohike ◽  
Minori Maeda ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
...  
Keyword(s):  
Biological Control ◽  
Suppressive Effect ◽  
Phytopathogenic Fungi ◽  
Dual Culture ◽  
Biological Control Agents ◽  
Bipolaris Oryzae ◽  
Biological Control Potential ◽  
Dual Culture Assay

Rhizoctonia solani is fungal plant pathogen that infects many different host plants. Recently, biological control agents that are friendly to the environment and ecosystems have attracted much attention as an alternative to the use of chemical fungicide which have been used worldwide to control soil borne pathogens including R. solani. In this study, 53 strains of actinomycetes isolated from environmental soils, and antifungal activities of them were assessed by the dual culture assay. Strain KT showed strong inhibitory activities against 8 phytopathogenic fungi. A great suppressive effect on R. solani growth was observed in the inoculation test of plants using cucumber and chin-geng-sai. In addition, infection of Bipolaris oryzae also could be suppressed in the detached leaf assay using oats. As a result of genetic analysis, it was shown that KT was a species closely related to Streptomyces lavenduligriseus NRRL B-3173T. However, as far as we know, there is no report for biological control agents using S. lavenduligriseus. This study suggests that the strain KT may useful as biological control agents to suppress various crop diseases.

scholarly journals Kemampuan Bakteri Endofit Akar dan Ubi Kentang untuk Menekan Penyakit Busuk Lunak (Erwinia carotovora pv. carotovora) pada Ubi

Agrikultura ◽  
2016 ◽  
Vol 27 (3) ◽  
Author(s):  
Noor Istifadah ◽  
Muhamad Salman Umar ◽  
Sudarjat Sudarjat ◽  
Luciana Djaya
Keyword(s):  
Biological Control ◽  
Potato Tuber ◽  
Endophytic Bacteria ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Soft Rot Disease ◽  
Post Harvest ◽  
Rot Disease

ABSTRACTThe abilities of endophytic bacteria from potato roots and tubers to suppress soft rot disease (Erwinia carotovora pv. carotovora) in potato tuberSoft rot disease caused by Erwinia carotovora pv. carotovora is one of limiting factors in cultivation and post harvest of potato. The eco-friendly control measure that can be developed for controlling the diseases is biological control. Microbes that are potential as biological control agents include endophytic bacteria. This paper discussed the results of study examining the potential of endophytic bacteria isolated from roots and tubers of potato to inhibit the growth of E. carotovora pv. carotovora in vitro and suppress soft rot disease in potato tuber. The results showed that among 24 isolates examined, four isolates of endophytic bacteria (one isolate from potato tuber and three isolates from potato roots) inhibited the growth of E. carotovora pv. carotovora in vitro with inhibition zone 3.5-6.8 mm. In the in vivo test, the isolates inhibited the soft rot disease in potato tuber by 71.5-86.4%. The isolate that tended to show relatively better inhibition in vitro and in vivo was isolate from potato tuber which is CK U3 (Lysinibacillus sp.)Keywords: Biological control, Endophytic bacteria, Post-harvest, Potato, Soft rot diseaseABSTRAKPenyakit busuk lunak yang disebabkan bakteri Erwinia carotovora pv. carotovora, merupakan salah satu kendala dalam budidaya dan pascapanen kentang. Cara pengendalian ramah lingkungan yang dapat dikembangkan untuk menekan penyakit tersebut adalah pengendalian biologi. Kelompok mikroba yang berpotensi sebagi agens pengendali biologi adalah bakteri endofit. Artikel ini mendiskusikan potensi isolat bakteri endofit yang berasal dari ubi dan akar kentang untuk menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dan menekan perkembangan penyakit busuk lunak pada ubi kentang. Hasil percobaan menunjukkan bahwa diantara 24 isolat bakteri yang diuji, terdapat empat isolat bakteri endofit (satu isolat dari ubi kentang dan tiga isolat dari akar kentang) yang dapat menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dengan zona penghambatan sebesar 3,5-6,8 mm. Pada pengujian secara in vivo, isolat-isolat tersebut dapat menekan perkembangan penyakit busuk lunak pada ubi kentang sebesar 71,5-86,4%. Isolat yang cenderung menunjukkan penghambatan relatif lebih baik secara in vitro dan in vivo adalah isolat bakteri endofit asal ubi kentang yaitu isolat CK U3 (Lysinibacillus sp.).Kata Kunci: Pengendalian biologi, Bakteri endofit, Pascapanen, Kentang, Penyakit busuk basah

scholarly journals Effect of China berry crude extracts on broad mites in vivo and in vitro

2008 ◽  
Vol 2 (1) ◽  
pp. 12-18
Author(s):  
Assma Gatta ◽  
Luaay K. Al – ani ◽  
Nabeel Al - ani
Keyword(s):  
Biological Control ◽  
Tissue Culture ◽  
Melia Azedarach ◽  
Concentration Increase ◽  
Water Extracts ◽  
Crude Extracts ◽  
Number Increase ◽  
Ethanol Extracts

Tissue culture were established from leaf and stem of china berry (Melia azedarach ) tree . Using MS media the best regulator to form callus were 6mg/l BAP, all other concentrations did not give callus . The crude extracts from leaves and callus established from leaves were extracted with water and ethanol with different concentrations. In ethanol extracts the least concentration 0.0001 half of the treated parasites were killed in 24 hours while the number increase as the concentration increase . However in callus the ethanol extracts were much higher about 8.5 were killed in the above concentration . In water extracts the least concentration 0.0001 killed half of the treated parasites in 24 hours .This number was increased 8 or 9 in 48 and 72 hours respectively . These results give us preliminary idea about the biological control of this dangerous parasite.

scholarly journals In vitro activity of human recombinant alpha-2b interferon against SARS-CoV-2 virus

2021 ◽  
Vol 66 (2) ◽  
pp. 123-128
Author(s):  
S. Ya. Loginova ◽  
V. N. Shсhukina ◽  
S. V. Savenko ◽  
S. V. Borisevich
Keyword(s):  
Cell Culture ◽  
Antiviral Activity ◽  
Viral Infections ◽  
Complete Suppression ◽  
Antiviral Efficacy ◽  
Prevention And Treatment ◽  
Proven Efficacy ◽  
High Antiviral Activity

Introduction. The pandemic spread of a new coronavirus infection, COVID-19, has caused a global emergency and attracted the attention of public health professionals and the population of all countries. A significant increase in the number of new cases of SARS-CoV-2 infection demonstrates the urgency of finding drugs effective against this pathogen.The aim of this work was to evaluate the in vitro antiviral efficacy of human recombinant alpha-2b interferon (IFN-α2b) against SARS-CoV-2 virus.Material and methods. The experiments had been carried out on Vero Cl008, the continuous line of African green monkey (Chlorocebus sabaeus) kidney cells. The effectiveness of the drugs was assessed by the suppression of viral reproduction in vitro. The biological activity was determined using titration of a virus-containing suspension in a Vero Cl008 cell culture by the formation of negative colonies.Results. The antiviral efficacy of the IFN-α2b-based medications, which have a high safety profile and proven efficacy in the prevention and treatment of influenza and acute respiratory viral infections (ARVI), has been studied against the new pandemic SARS-CoV-2 virus in vitro experiments in Vero C1008 cell culture. IFN-α2b effectively inhibits the reproduction of the virus when applied both 24 hrs before and 2 hrs after infection. In the IFN-α2b concentration range 102–106 IU/ml a complete suppression of the reproduction of the SARS-CoV-2 virus had been demonstrated.Discussion. IFN-α2b demonstrated in vitro high antiviral activity against SARS-CoV-2. In addition, the substance has a high chemotherapeutic index (>1000).Conclusion. Medications for intranasal use based on IFN-α2b have high antiviral activity and are promising drugs for in vivo study in terms of prevention and treatment of COVID-19.

ISOLATION, IDENTIFICATION AND CHARACTERIZATION OF BACTERIAL ANTAGONISTS OF THE DRAGON FRUIT FUNGAL PATHOGEN Neoscytalidium dimidiatum

2021 ◽  
Vol 44 (02) ◽  
Author(s):  
NGUYEN NGOC AN ◽  
HUA HUYNH MINH THAO ◽  
HO NGUYEN HOANG YEN ◽  
NGUYEN THI DIEU HANH ◽  
NGUYEN LE HIEN HOA ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Pathogenic Fungi ◽  
Fungal Spore ◽  
Stem Canker ◽  
Antagonistic Effect ◽  
Fruit Rot ◽  
Economic Losses ◽  
Neoscytalidium Dimidiatum ◽  
Dragon Fruit

Dragon fruit or pitahaya (Hylocereus spp.) are famous for their nutrient-rich favourable taste, which brings high economic value to subtropical and tropical countries. However, dragon fruit cultivation all over the world is threatened by fungal pathogens and among them, Neoscytalidium dimidiatum has recently been shown to be responsible for stem canker and fruit rot which cause big economic losses. In order to find an environmentally friendly way to control this pathogen, five out of sixty-nine bacterial isolates used in a screening test for antifungal activity were selected. All five strains appeared to be aerobic Gram positive spore forming bacteria suggesting that they all belong to the Bacillus genus. Cell-free culture supernatants of these strains were found to strongly inhibit both fungal spore germination and mycelia growth in vitro for at least 5 days. The strain D19 which possessed the highest antagonistic effect was further identified to be Bacillus amyloliquefaciens, a well-known species shown to have antifungal effect against several other pathogenic fungi. Thus, the results of this study opened a new promising perspective to prevent Neoscytalidium dimidiatum infection during cultivation of dragon fruit.

scholarly journals Bacillus velezensis 83 a bacterial strain from mango phyllosphere, useful for biological control and plant growth promotion

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Karina A. Balderas-Ruíz ◽  
Patricia Bustos ◽  
Rosa I. Santamaria ◽  
Víctor González ◽  
Sergio Andrés Cristiano-Fajardo ◽  
...  
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Biological Control Agent ◽  
Gene Clusters ◽  
In Vitro Assays ◽  
Shoot Biomass ◽  
Plant Growth Promoting Bacteria ◽  
Bacillus Velezensis

Abstract Bacillus velezensis 83 was isolated from mango tree phyllosphere of orchards located in El Rosario, Sinaloa, México. The assessment of this strain as BCA (biological control agent), as well as PGPB (plant growth-promoting bacteria), were demonstrated through in vivo and in vitro assays. In vivo assays showed that B. velezensis 83 was able to control anthracnose (Kent mangoes) as efficiently as chemical treatment with Captan 50 PH™ or Cupravit hidro™. The inoculation of B. velezensis 83 to the roots of maize seedlings yielded an increase of 12% in height and 45% of root biomass, as compared with uninoculated seedlings. In vitro co-culture assays showed that B. velezensis 83 promoted Arabidopsis thaliana growth (root and shoot biomass) while, under the same experimental conditions, B. velezensis FZB42 (reference strain) had a suppressive effect on plant growth. In order to characterize the isolated strain, the complete genome sequence of B. velezensis 83 is reported. Its circular genome consists of 3,997,902 bp coding to 3949 predicted genes. The assembly and annotation of this genome revealed gene clusters related with plant-bacteria interaction and sporulation, as well as ten secondary metabolites biosynthetic gene clusters implicated in the biological control of phytopathogens. Despite the high genomic identity (> 98%) between B. velezensis 83 and B. velezensis FZB42, they are phenotypically different. Indeed, in vitro production of compounds such as surfactin and bacillomycin D (biocontrol activity) and γ-PGA (biofilm component) is significantly different between both strains.

Properties of an Inhibitor of Platelet Aggregation and Thromboxane Synthesis Isolated from Onion and Garlic

1979 ◽  
Author(s):  
A.N. Makheja ◽  
J.Y. Vanderhoek ◽  
J.M. Bailey
Keyword(s):  
Platelet Aggregation ◽  
Allium Sativum ◽  
Chloroform Extract ◽  
Complete Suppression ◽  
Inhibit Platelet Aggregation ◽  
Platelet Activity ◽  
Rabbit Platelets ◽  
Mild Acid

Onion (allium cepa) and garlic (allium sativum) inhibit platelet aggregation both in vitro and in vivo. An oily chloroform extract of onion was prepared and the anti-platelet activity was purified using standard chromatographic procedures. Inhibitory activity from onion is associated with a non-polar material not inactivated by mild acid or alkali and stable to heating. Similar inhibitory properties were observed with both onion oil and garlic oil (I50/ml PRP = 30-100 μg with different samples of human and rabbit platelets). Platelets incubated with onion inhibitor and 1-14C arachidonic acid showed striking changes in the pattern of radioactive metabolites formed. Most apparent was the almost complete suppression of thromboxane B2 synthesis and the appearance of a new metabolite identified as a product of the platelet lipoxygenase. Measurements of oxygen consumption of treated platelets indicate that these materials inhibit the platelet cyclooxygenase. Similar inhibition of sheep vesicular gland cyclooxygenase was observed with onion oil but not with garlic. Gas chromatographic and mass spectrometric analyses of active extracts of onion and garlic show differences in several major components which may relate to the observed differences in biological activity. The results indicate that two members of the allium family commonly used in the diet contain chemically similar compounds which inhibit platelet aggregation by blocking thromboxane synthesis.

In vivo production of entomopathogenic nematodes suppressed by asymptomatic bacterial contaminants

Nematology ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 917-925
Author(s):  
Akanksha Upadhyay ◽  
Sharad Mohan
Keyword(s):  
Biological Control ◽  
Entomopathogenic Nematodes ◽  
Photorhabdus Luminescens ◽  
Ochrobactrum Anthropi ◽  
Progeny Production ◽  
Bacterial Contaminants ◽  
Significant Difference ◽  
Biological Control Of Insects

Summary Entomopathogenic nematodes (EPN) are excellent biological control agents possessing recycling ability as one of their major attributes. We report the presence of asymptomatic bacteria that can lead to disrupted or low progeny production in Heterorhabditis indica. In a one-to-one in vitro competitive bioassay with contaminants associated with H. indica cuticle, there was a significant suppression in the growth of Sphingomonas koreensis when stressed with the nematode symbiont Photorhabdus luminescens; however, P. luminescens was suppressed when sandwiched between Ochrobactrum anthropi. Bacillus bombysepticus associated with laboratory-reared Galleria when stressed by P. luminescens was significantly suppressed, but not so in the reverse assay. Both O. anthropi and B. bombysepticus were found to be insecticidal to Galleria larvae when fed orally. Tripartite interactive studies on the growth and multiplication of H. indica-P. luminescens symbionts in Galleria larvae, predisposed to S. koreensis, revealed no significant difference initially in the hermaphrodite formation, but subsequently there was a significant decline in the formation of amphimictic females and the final production of infective juveniles. In in vitro studies, none of the contaminants supported the growth and development of axenic H. indica. Adequate precautions should be taken to maintain proper hygiene to eliminate such contaminants while culturing the Galleria and EPN for use in the biological control of insects.

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