scholarly journals Qualitative Analysis of a Cholera Bacteriophage Model

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Prasenjit Das ◽  
Debasis Mukherjee
Keyword(s):  
Vibrio Cholerae ◽  
Temporal Dynamics ◽  
Reproduction Number ◽  
Biological Control Agent ◽  
Control Agent ◽  
Lytic Bacteriophage ◽  
Globally Asymptotically Stable ◽  
Model Dynamics ◽  
Global Threat

Cholera still remains as a severe global threat and is currently spreading in Africa and other parts of the world. The role of lytic bacteriophage as an intervention of cholera outbreaks is investigated using a mathematical model. Dynamics of cholera is discussed on basis of the basic reproduction number . Conditions of Hopf bifurcation are also derived for a positive net growth rate of Vibrio cholerae. Stability analysis and numerical simulations suggest that bacteriophage may contribute to lessening the severity of cholera epidemics by reducing the number of Vibrio cholerae in the environment. Hence with the presence of phage virus, cholera is self-limiting in nature. By using phage as a biological control agent in endemic areas, one may also influence the temporal dynamics of cholera epidemics while reducing the excessive use of chemicals. We also performed stochastic analysis which suggests that the model system is globally asymptotically stable in probability when the strengths of white noise are less than some specific quantities.

Small Mammals as Predators of Sawflies

1955 ◽  
Vol 87 (3) ◽  
pp. 121-123 ◽  
Author(s):  
C. H. Buckner
Keyword(s):  
Small Mammals ◽  
Biological Control Agent ◽  
Control Agent ◽  
Moderate Risk ◽  
Neodiprion Abietis ◽  
Ample Opportunity ◽  
Pristiphora Erichsonii ◽  
Mammalian Predators ◽  
One Year

The greatest predatory effect of small mammals is exerted upon insects that spend a portion of their life cycle on the ground or in the soil. Sawflies afford ample opportunity for mammalian predation, since they drop to the ground as mature larvae and spin cocoons in the soil. Such sawflies as Neodiprion abietis Harr., which remain within the cocoon for about three weeks, undergo only moderate risk of being preyed upon by small mammal. However, Pristiphora erichsonii (Htg.) remains within the cocoon from about mid-August until the following June, or even over more than one year, thus greatly extending the vulnerable period. Earlier investigations suggest that small mammals may comprise the largest single biological control agent acting against this insect (Graham 1928, Lejeune 1951), but the exact role of mammalian predators of forest insects has yet to be established.

scholarly journals Characterization of Migration and Induced Resistance of Rhizobium Vitis Strain ARK-1, a Biological Control Agent Against Grapevine Crown Gall Disease

2020 ◽  
Author(s):  
Akira Kawaguchi ◽  
Yoshiteru Noutoshi
Keyword(s):  
Crown Gall ◽  
Temporal Dynamics ◽  
Biological Control Agent ◽  
Control Agent ◽  
Systemic Resistance ◽  
Marker Genes ◽  
Cell Detection ◽  
Induced Expression ◽  
Crown Gall Disease ◽  
Grapevine Crown Gall

Abstract A nonpathogenic strain ARK-1 of Rhizobium vitis has an antagonistic activity toward tumorigenic (Ti) strain of R. vitis, a causal agent of grapevine crown gall disease, and works as a biocontrol agent. We have demonstrated that the gall formation was fully suppressed when ARK-1 was co-inoculated with Ti into the grapevine stem at a 1:1 ratio. For practical use of ARK-1 in agriculture, understanding the temporal dynamics of the bacterial habitat on host plants and the biocontrol property are needed in order to develop proper application methods. Here we demonstrated that the gall incidence by Ti was reduced to about 50% when ARK-1 was pre-inoculated at both upper and lower positions on the grapevine stem 3 cm away from the Ti-inoculation point 5 days before. The bacterial cell detection assay in the grapevine tissue revealed that ARK-1 could migrate at least 3 cm in 5 days. Inoculations of ARK-1 or Ti induced expression of marker genes for defense-related phytohormones such as salicylic acid, jasmonic acid, and ethylene in grapevine within 3 days but they were diminished by 6 days. Inoculation of Ti 5 days after ARK-1 pre-inoculation induced expression of the marker genes except for the LOX-9 gene in a basically similar way to those without the pre-inoculation, suggesting that ARK-1 did not induce typical acquired systemic resistance or induced systemic resistance in grapevine, while the transcript of LOX-9 was detected at 24 and 48 hours after the Ti inoculation when ARK-1 was pre-inoculated, unlike the un-inoculated condition. ARK-1 primed the induction of certain defense genes and it may take part in its biocontrol activity.

scholarly journals Mathematical analysis of an age structured epidemic model with a quarantine class

2021 ◽  
Author(s):  
Bedreddine AINSEBA ◽  
Tarik Touaoula ◽  
Zakia Sari
Keyword(s):  
Reproduction Number ◽  
Asymptotic Behavior Of Solutions ◽  
Model Parameters ◽  
Qualitative Behavior ◽  
Asymptotically Stable ◽  
Globally Asymptotically Stable ◽  
Age Structured ◽  
The Stability ◽  
The Impact

In this paper, an age structured epidemic Susceptible-Infected-Quarantined-Recovered-Infected (SIQRI) model is proposed, where we will focus on the role of individuals that leave their class of quarantine before being completely recovered and thus will participate again to the transmission of the disease. We investigate the asymptotic behavior of solutions by studying the stability of both trivial and positive equilibria. In order to see the impact of the different model parameters like the relapse rate on the qualitative behavior of our system, we firstly, give the explicit expression of the epidemic reproduction number $R_{0}.$ This number is a combination of the classical epidemic reproduction number for the SIQR model and a new epidemic reproduction number corresponding to the individuals infected by a relapsed person from the R-class. It is shown that, if $R_{0}\leq 1$, the disease free equilibrium is globally asymptotically stable and becomes unstable for $R_{0}>1$. Secondly, while $R_{0}>1$, a suitable Lyapunov functional is constructed to prove that the unique endemic equilibrium is globally asymptotically stable on some subset $\Omega_{0}.$

scholarly journals The Trends in the Evaluation of Fusarium Wilt of Chickpea

2021 ◽  
Author(s):  
Chandan Singh ◽  
Deepak Vyas
Keyword(s):  
Biological Control ◽  
Fusarium Wilt ◽  
Biological Control Agent ◽  
Am Fungi ◽  
Control Agent ◽  
Wilt Disease ◽  
Evaluation Strategies ◽  
Resistant Varieties ◽  
Tools And Techniques

Chickpea (Cicer arietinum L.) is one of the important annual legume crops, cultivated throughout the India since ancient time. It is also grown in many countries of the world. The crop has been facing numerous biotic and abiotic constraints. Among biotic constraint crop affected adversely by diseases, caused by many pathogens. Ever since 1918 when for the first time wilt disease of chickpea was reported and Fusarium oxysporum f. sp. ciceri was the causal organism many strategies have been adopted to control the wilt disease. The controlling methods included conventional as well as modern one. However, more and more emphasis was given on biological control agents such as AM fungi and Trichoderma. The role of AM fungi have been evaluated for controlling the wilt disease similarly role of Trichoderma is thoroughly established biological control agent against Fusarium wilt. With the advent of modern tools and techniques developing markers, resistant varieties, all such sources enable us to reduce the effect of pathogens. Here an attempted has been made to acknowledge the trend of disease management and evaluation strategies of Fusarium wilt of chickpea for getting better yields of the crop.

Efficacy of the predatory mite Cydnoseius negevi (Swirskii & Amitai) (Acari: phytoseiidae) as a shared predator for sucking pests on sweet pepper in a net house in Egypt

2021 ◽  
Author(s):  
El-laithy A.y. M., E, M.elseedy ◽  
Hoda E. Hussein
Keyword(s):  
Population Density ◽  
Biological Control Agent ◽  
Phytoseiulus Persimilis ◽  
Sweet Pepper ◽  
Predatory Mite ◽  
Control Agent ◽  
Mean Values ◽  
Negative Effect ◽  
Tetranychus Urticae Koch

A field experiment was carried out to evaluate the efficacy of the native predatory mite Cydnoseius negevi (Swirski and Amitai) (=Typlodromus negevi) as a biological control agent for Bemisia tabaci (Gennadius) complex, Onion thrips Thrips tapaci (Lindeman) and Tetranychus urticae (Koch). The efficacy of Phytoseiulus persimilis (Athias-Henriot) against these pests was also evaluated. The data obtained revealed reduction in population density of the above-mentioned pests in the experimental plots for P. persimilis and C. negivi compared to the control plot. Mean population density of each of the pests ranging from 32.2–0.5, 284.4–2.0 and 441.8–2.0 individuals / leaf for T. urticae, in the three plots respectively. The mean values of B. tabaci fluctuated between 41.1–2.1, 16.2–1.0 and 57.3–3.6. individuals / leaf and T. tabaci between 20.1–2.6, 13.7–1.4 and 24.9–1.9 individuals / leaf respectively. A slight non-consumptive negative effect is shown by P. persimilis against the pests B. tabaci and T. tabaci. This preliminary experiment hopefully will enhance the role of the native predator C. negevi to play a role in bio-control and its mass augmentation.

A new species of Balaustium von Heyden, 1826 (Acari: Actinotrichida, Erythraeidae) from Spain

Zootaxa ◽  
2012 ◽  
Vol 3178 (1) ◽  
pp. 1 ◽  
Author(s):  
JOANNA MĄKOL ◽  
YVES ARIJS ◽  
FELIX WÄCKERS
Keyword(s):  
New Species ◽  
Potential Role ◽  
Biological Control Agent ◽  
Feeding Habits ◽  
Control Agent ◽  
Food Spectrum ◽  
Mode Of Reproduction ◽  
Large Numbers ◽  
A New Species

An erythraeid mite, Balaustium hernandezi sp. nov., was found in large numbers in a greenhouse in Spain. The larva,deutonymph and female of the new species are described based on material obtained during experimental rearing. Dataand information on feeding habits, food spectrum, mode of reproduction and life cycle are provided. The potential role of the species as a biological control agent is discussed.

Role of Sporormiellasimilis as a potential bioprotectant of Populustremuloides wood against the blue-stain fungus Ophiostomapiliferum

1994 ◽  
Vol 24 (11) ◽  
pp. 2235-2239 ◽  
Author(s):  
P. Chakravarty ◽  
L. Trifonov ◽  
L.J. Hutchison ◽  
Y Hiratsuka ◽  
W.A. Ayer
Keyword(s):  
Culture Filtrate ◽  
Liquid Culture ◽  
Biological Control Agent ◽  
Control Agent ◽  
Dual Culture ◽  
Blue Stain ◽  
Agar Media ◽  
Fungitoxic Effect

Interactions between Sporormiellasimilis Khan & Cain and the blue-stain fungus Ophiostomapiliferum (Fr.) H. & P. Sydow, both isolated from Populustremuloides Michx. wood, were investigated. Sporormiellasimilis significantly reduced the growth of O. piliferum in vitro when grown in dual culture, in addition to inhibiting the growth of O. piliferum on agar media and in liquid culture when treated with a culture filtrate of S. similis. Ophiostomapiliferum failed to colonize P. tremuloides wood chips when they were preinoculated with S. similis. Ten known compounds were isolated and identified from the culture filtrate of S. similis. These compounds showed varied fungitoxic effect against O. piliferum at concentrations of 1 to 1000 μg/mL. The potential for S. similis as a biological control agent against O. piliferum on P. tremuloides is discussed.

scholarly journals Molecular Identification of Bacillus Derived from the Common Carp Intestine and Their Antibiotics Resistance

2020 ◽  
Vol 5 (2) ◽  
pp. 294-302
Author(s):  
Yuniar Mulyani ◽  
Karimah Syakirotin ◽  
Kiki Haetami ◽  
Yeni Mulyani ◽  
Evi Liviawaty ◽  
...  
Keyword(s):  
Common Carp ◽  
Biological Control Agent ◽  
Control Agent ◽  
Bacillus Species ◽  
Antibiotics Resistance ◽  
Aquatic Biota ◽  
Molecular Method ◽  
The Common ◽  
Negative Impacts

The use of bacteria as a biological control agent in aquaculture is such new hope overcoming the negative impacts of the impropriate use of antibiotics. Bacillus is widely known as a potential probiotic for aquaculture, especially which are derived from aquatic biota. Due to a concern that the role of Bacillus as a probiotic agent will be disrupted by residues of antibiotics in the water, this research aimed to identify Bacillus species from common carp intestine based on the molecular method and investigate their resistance to some com-mercial antibiotics that widely used in aquaculture. Chloramphenicol, ampicillin, and metronidazole were used to determine the Bacillus resistance to antibiotics using the Kirby Bauer method. The resistance assay was carried out with a bacterial density of 108 CFU/mL. The results showed that Bacillus isolates derived from common carp  intestine were closely related and resistant to antibiotics. Isolates that resistant to the three types of antibiotics were Cc.1.9 (CgN9) and Cc.2.18 (CgM18).

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