PeerJ Preprints: Agricultural Sciencehttps://peerj.com/preprints/index.atom?journal=peerj&subject=100Agricultural Science articles published in PeerJ PreprintsIsolation and characterization of psychrotrophic proteolytic bacteria from landfill site under temperate climatic conditions of Kashmir Himalayahttps://peerj.com/preprints/273912019-12-212019-12-21Basharat HamidArshid JehangirZahoor Ahmad BabaMuneer Ahmad WaniImran Khan
The temperate climatic regions face the problem of waste accumulation due to lower environmental temperatures. However, these regions harbor cold active microbes viz. psychrotrophic proteolytic bacteria that play an important role in the degradation of protenaceous materials of the waste stream. Hence in the present study psychrotrophic proteolytic bacteria were isolated from waste samples collected from landfill site by using random sampling method under environmental temperature of 10oC. By using serial dilution and spread plate technique a total of 8 morphologically different psychrotrophic proteolytic bacteria were isolated on skim milk agar media at pH of 7.0 and temperature of 10°C after 48hours. Under in-vitro conditions all the isolates produced significant quantities of protease over the control and diameters of hydrolysis zones ranged between 2 to 18 mm at temperature range of 5 to 20oC and after 72 hours. The corresponding quantitative protease activities of the isolates was significant that ranged between 0.5 to 2.25 U/ml and the isolate PB2 was most efficient with highest protease activity of 2.25U/ml at 20oC. Based on 16SrRNA analysis the isolate was identified as Pseudomonas florescence with 96% similarity. It was concluded that the isolates can grow in wide ranges of temperature and could be used for enhanced decomposition of organic wastes during lower temperature conditions in cold regions. Further the isolates could have industrial applications due to the production of cold active proteases that would help economic benefits through energy conservation.
The temperate climatic regions face the problem of waste accumulation due to lower environmental temperatures. However, these regions harbor cold active microbes viz. psychrotrophic proteolytic bacteria that play an important role in the degradation of protenaceous materials of the waste stream. Hence in the present study psychrotrophic proteolytic bacteria were isolated from waste samples collected from landfill site by using random sampling method under environmental temperature of 10oC. By using serial dilution and spread plate technique a total of 8 morphologically different psychrotrophic proteolytic bacteria were isolated on skim milk agar media at pH of 7.0 and temperature of 10°C after 48hours. Under in-vitro conditions all the isolates produced significant quantities of protease over the control and diameters of hydrolysis zones ranged between 2 to 18 mm at temperature range of 5 to 20oC and after 72 hours. The corresponding quantitative protease activities of the isolates was significant that ranged between 0.5 to 2.25 U/ml and the isolate PB2 was most efficient with highest protease activity of 2.25U/ml at 20oC. Based on 16SrRNA analysis the isolate was identified as Pseudomonas florescence with 96% similarity. It was concluded that the isolates can grow in wide ranges of temperature and could be used for enhanced decomposition of organic wastes during lower temperature conditions in cold regions. Further the isolates could have industrial applications due to the production of cold active proteases that would help economic benefits through energy conservation.Bacillus induced to biosynthesize VOCs & nitriles may benefit agriculture.https://peerj.com/preprints/26112019-09-302019-09-30Guenevere PerryDiane Perry
The scope of the project was to identify the possible agricultural applications for bacteria induced to synthesize nitriles and VOCs. The study was randomized. Cucurbit seeds and Bacillus licheniformis were selected as the plant and microbial models for two trial studies. In trial 1, 90 cucumber seeds were cultured with B.licheniformis induced to synthesize VOCs (including ethanol, 3-methyl-1-butanol, pentanol), esters (ethyl acetate), and acetonitriles. After 2 weeks the induced bacteria increased seed germination by 68% compared to control samples. Several seedlings were transferred to a small garden, infested with soil nematodes. Roots of control and induced samples appeared affected. Control samples appeared stunted in growth with decreased productivity, but cucumber plants initially planted with induced bacteria were noticeably larger in size with good productivity. Induced Bacillus increased the number of blossoms and cucumber per plant by 125% compared to control samples. Induced Bacillus did not increase solubility of nitrogen, phosphorous, or potassium in the soil, but appeared to increase plant health and defenses against pathogenic infections. Though the study findings are preliminary, soil microbes induced to synthesize VOCs and nitriles may improve plant health and productivity in cucurbit plants.
The scope of the project was to identify the possible agricultural applications for bacteria induced to synthesize nitriles and VOCs. The study was randomized. Cucurbit seeds and Bacillus licheniformis were selected as the plant and microbial models for two trial studies. In trial 1, 90 cucumber seeds were cultured with B.licheniformis induced to synthesize VOCs (including ethanol, 3-methyl-1-butanol, pentanol), esters (ethyl acetate), and acetonitriles. After 2 weeks the induced bacteria increased seed germination by 68% compared to control samples. Several seedlings were transferred to a small garden, infested with soil nematodes. Roots of control and induced samples appeared affected. Control samples appeared stunted in growth with decreased productivity, but cucumber plants initially planted with induced bacteria were noticeably larger in size with good productivity. Induced Bacillus increased the number of blossoms and cucumber per plant by 125% compared to control samples. Induced Bacillus did not increase solubility of nitrogen, phosphorous, or potassium in the soil, but appeared to increase plant health and defenses against pathogenic infections. Though the study findings are preliminary, soil microbes induced to synthesize VOCs and nitriles may improve plant health and productivity in cucurbit plants.Ethylene induced nitrile and VOC synthesis by soil microbes; Improved root elongation & reduced risk of fungal infection in plants.https://peerj.com/preprints/5432019-09-272019-09-27Guenevere PerryDiane Perry
The scope of the project was to develop a method to induce soil microbes to inhibit fungal infection and improve root elongation. The study was randomized. Gladiolus bulbs selected for the study were visibly inspected to for viability and visible signs of infection. Two trials were conducted from Aug. 5th – Sept. 5th 2014 with 4 replicates per condition over a 7-d period in damp outdoor conditions in late summer. A mixed culture of plant growth promoting rhizobacteria (PGPR) were collected from soil surrounding the roots of young fruit bearing trees. Microbes were mixed with minimal media (no-carbon source), and cultured with an ethylene and used as potting soil. Bulbs planted in ethylene induced soil displayed 0% visible fungal growth, while 38% of bulbs grown in control conditions displayed some form of fungal growth and/or infection. Ethylene induced soil increased root length by 225% in bulbs in 7-d period. GC Mass Spectrophotometry data suggest ethylene may induce soil microbes to synthesize several VOCs including (ethanol, 3-methyl-1-butanol, pentanol) and esters (ethyl acetate), that may have synergistic benefits to lower the risk of fungal infection by soil mold, while nitrile compounds improve root elongation. The findings are preliminary, additional studies are required to understand the mechanism.
The scope of the project was to develop a method to induce soil microbes to inhibit fungal infection and improve root elongation. The study was randomized. Gladiolus bulbs selected for the study were visibly inspected to for viability and visible signs of infection. Two trials were conducted from Aug. 5th – Sept. 5th 2014 with 4 replicates per condition over a 7-d period in damp outdoor conditions in late summer. A mixed culture of plant growth promoting rhizobacteria (PGPR) were collected from soil surrounding the roots of young fruit bearing trees. Microbes were mixed with minimal media (no-carbon source), and cultured with an ethylene and used as potting soil. Bulbs planted in ethylene induced soil displayed 0% visible fungal growth, while 38% of bulbs grown in control conditions displayed some form of fungal growth and/or infection. Ethylene induced soil increased root length by 225% in bulbs in 7-d period. GC Mass Spectrophotometry data suggest ethylene may induce soil microbes to synthesize several VOCs including (ethanol, 3-methyl-1-butanol, pentanol) and esters (ethyl acetate), that may have synergistic benefits to lower the risk of fungal infection by soil mold, while nitrile compounds improve root elongation. The findings are preliminary, additional studies are required to understand the mechanism.Functional characterization of a new maize heat shock transcription factor gene ZmHsf01 playing important roles in thermotolerancehttps://peerj.com/preprints/279872019-09-262019-09-26Huaning ZhangGuoliang LiYuanyuan ZhangYujie ZhangHongbo ShaoDong HuXiulin Guo
Background. The yield of maize crop is influenced seriously by heat waves. Plant heat shock transcription factors (Hsfs) play a key regulatory role in heat shock signal transduction pathway. Method. In this study, a new heat shock transcription factor gene, ZmHsf01 (accession number: MK888854) , was cloned from maize young leaves using homologous cloning method. The transcriptional level of ZmHsf01 were detected by qRT-PCR in different tissues or under heat shock, abscisic acid (ABA) and hydrogen peroxide (H2O2) treatment. The transgenic yeast and Arabidopsis were used to study the gene function of ZmHsf01. Result. The coding sequence (CDS) of ZmHsf01 was 1176 bp and encoded a protein that consisted of 391 amino acids. The homologous analysis result showed that ZmHsf01 and SbHsfA2d had the highest protein sequence identity. Subcellular localization experiments demonstrated that ZmHsf01 is localized to the nucleus. ZmHsf01 was expressed in many maize tissues and was up-regulated by heat stress. ZmHsf01 was up-regulated in roots and down-regulated in leaves by ABA and H2O2treatments. In yeast, ZmHsf01-overexpressing cells showed increased thermotolerance. In Arabidopsis seedlings, ZmHsf01 complemented the thermotolerance defects of athsfa2 mutant and ZmHsf01-overexpressing lines presented enhanced basal and acquired thermotolerance. Compared to wild type (WT) seedlings, ZmHsf01-overexpressing lines showed increased chlorophyll content after heat stress. The expression level of heat shock protein genes was up-regulated higher in ZmHsf01-overexpressing Arabidopsis seedlings than that in WT. These results suggested that ZmHsf01 plays a vital role in plant response to heat stress.
Background. The yield of maize crop is influenced seriously by heat waves. Plant heat shock transcription factors (Hsfs) play a key regulatory role in heat shock signal transduction pathway. Method. In this study, a new heat shock transcription factor gene, ZmHsf01 (accession number: MK888854), was cloned from maize young leaves using homologous cloning method. The transcriptional level of ZmHsf01 were detected by qRT-PCR in different tissues or under heat shock, abscisic acid (ABA) and hydrogen peroxide (H2O2) treatment. The transgenic yeast and Arabidopsis were used to study the gene function of ZmHsf01. Result. The coding sequence (CDS) of ZmHsf01 was 1176 bp and encoded a protein that consisted of 391 amino acids. The homologous analysis result showed that ZmHsf01 and SbHsfA2dhad the highest protein sequence identity. Subcellular localization experiments demonstrated that ZmHsf01 is localized to the nucleus. ZmHsf01 was expressed in many maize tissues and was up-regulated by heat stress. ZmHsf01 was up-regulated in roots and down-regulated in leaves by ABA and H2O2treatments. In yeast, ZmHsf01-overexpressing cells showed increased thermotolerance. In Arabidopsis seedlings, ZmHsf01 complemented the thermotolerance defects of athsfa2 mutant and ZmHsf01-overexpressing lines presented enhanced basal and acquired thermotolerance. Compared to wild type (WT) seedlings, ZmHsf01-overexpressing lines showed increased chlorophyll content after heat stress. The expression level of heat shock protein genes was up-regulated higher in ZmHsf01-overexpressing Arabidopsis seedlings than that in WT. These results suggested that ZmHsf01 plays a vital role in plant response to heat stress.Ethylene induced soil delays ripening in organic bananas.https://peerj.com/preprints/5062019-09-252019-09-25Guenevere PerryDiane Williams
The scope of the project was to develop a method to induce soil bacteria to biosynthesize compounds that retard the effects of ethylene induced ripening in climacteric fruits. The study was randomized. Organic bananas selected for the study were visibly inspected to ensure the fruit was unripen with no visible signs of bruising, spotting, or infection from a local distributor. Four trials were conducted from June 5th - August 5th 2014 with 3 replicates (3-4 bananas per experimental unit) in 4 trial studies for 3 days at room temperature. A mixed culture of plant growth promoting rhizobacteria (PGPR) were collected from soil surrounding the roots of young fruit bearing trees. Microbes were mixed with no-carbon source media, and cultured with an ethylene for 3 d at room temperature in a closed container. Induced soil was used to delay ripening. Microbes induced with media and ethylene delayed ripening 100% of the time in all experimental units compared to control samples, while microbes cultured with media (no ethylene) delayed ripening less than 10% of the time compared to the control. These cells also appeared to increase the incidence of fungal infection in the fruit. The findings suggest induced microbes may convert ethylene into ethanol then acetaldehyde. The two compounds may form an acetaldehyde/ethanol vapor that delays ripening, and a secondary nitrile compound that inhibits fungal growth.
The scope of the project was to develop a method to induce soil bacteria to biosynthesize compounds that retard the effects of ethylene induced ripening in climacteric fruits. Thestudy was randomized. Organic bananas selected for the study were visibly inspected to ensure the fruit was unripen with no visible signs of bruising, spotting, or infection from a local distributor. Four trials were conducted from June 5th - August 5th 2014 with 3 replicates (3-4 bananas per experimental unit) in 4 trial studies for 3 days at room temperature. A mixed culture of plant growth promoting rhizobacteria (PGPR) were collected from soil surrounding the roots of young fruit bearing trees. Microbes were mixed with no-carbon source media, and cultured with an ethylene for 3 d at room temperature in a closed container. Induced soil was used to delay ripening. Microbes induced with media and ethylene delayed ripening 100% of the time in all experimental units compared to control samples, while microbes cultured with media (no ethylene) delayed ripening less than 10% of the time compared to the control. These cells also appeared to increase the incidence of fungal infection in the fruit. The findings suggest induced microbes may convert ethylene into ethanol then acetaldehyde. The two compounds may form an acetaldehyde/ethanol vapor that delays ripening, and a secondary nitrile compound that inhibits fungal growth.Proximate composition and quantitative analysis of benzoyl peroxide and benzoic acid in the wheat flour samples: wheat flour qualityhttps://peerj.com/preprints/279692019-09-182019-09-18Numrah NisarFaiza MustafaArifa TahiraRashad Waseem Khan QadriYaodong YangMuhammad Imran Khan
Background. Extensive milling processes have deprived wheat flour from essential nutrients. Objective of the current study was to assess the nutritive quality of commercial wheat flour (soft flour/SF) through analyses of proximate composition and functional properties as well as quantification of benzoyl peroxide (BP; added as bleaching agent in the SF). Methods. Test samples included commercial soft flour samples purchased from the local supplier from different flour mills (with additives) and a control sample without additives was prepared by grinding the seeds harvested from wheat crop grown in the experimental field of University of Agriculture, Faisalabad, under optimized field conditions without any fertilizer and insecticide. Benzoyl peroxide and Benzoic Acid quantification was performed through High Performance Liquid Chromatography Results. Results when compared with the whole wheat flour (WF; never received additives) indicated that SF had lesser fiber, protein and ash contents, whereas, higher damaged starch, fat, gluten and bulk density. A parallel experiment under selected conditions (temperature, time and solute concentration) showed dissociation of BP into BA soon after the exposure. Observed BA range (13.77 mg/g after 16hrs) in SF and exposure level assessment (44.3±1.36 mg/kg/BW) showed higher intake of BA on the consumption of SF. Results revealed superiority of WF over SF in nutritive qualities as well as free of toxicants such as BA. KEYWORDS: Benzoyl peroxide; Benzoic acid; Soft Flour; Whole Wheat Flour; High Performance Liquid Chromatography
Background. Extensive milling processes have deprived wheat flour from essential nutrients. Objective of the current study was to assess the nutritive quality of commercial wheat flour (soft flour/SF) through analyses of proximate composition and functional properties as well as quantification of benzoyl peroxide (BP; added as bleaching agent in the SF). Methods. Test samples included commercial soft flour samples purchased from the local supplier from different flour mills (with additives) and a control sample without additives was prepared by grinding the seeds harvested from wheat crop grown in the experimental field of University of Agriculture, Faisalabad, under optimized field conditions without any fertilizer and insecticide. Benzoyl peroxide and Benzoic Acid quantification was performed through High Performance Liquid Chromatography Results. Results when compared with the whole wheat flour (WF; never received additives) indicated that SF had lesser fiber, protein and ash contents, whereas, higher damaged starch, fat, gluten and bulk density. A parallel experiment under selected conditions (temperature, time and solute concentration) showed dissociation of BP into BA soon after the exposure. Observed BA range (13.77 mg/g after 16hrs) in SF and exposure level assessment (44.3±1.36 mg/kg/BW) showed higher intake of BA on the consumption of SF. Results revealed superiority of WF over SF in nutritive qualities as well as free of toxicants such as BA. KEYWORDS: Benzoyl peroxide; Benzoic acid; Soft Flour; Whole Wheat Flour; High Performance Liquid ChromatographyRhodococcus sp. may convert ethylene to acetaldehyde to slow ripening in climacteric fruit.https://peerj.com/preprints/33982019-09-172019-09-17Guenevere Perry
Pre-Print Update. Previous studies suggested Rhodococcus rhodochrous and Bacillus licheniformis cells converted ethylene to a nitrile compound to delay the effects of ripening, (Perry, G. Nov. 9, 2017). However, there may be an alternative compound that plays a more significant role in induced Rhodococcus and Bacillus ability to delay ripening. It has been known for years that Rhodococcus can convert the alkyne compound acetylene to acetaldehyde and potentially ethanol as a secondary product (DeBont, 1980).
This pre-print revisit re-examines the prior data to determine if the tri-phasic system previously discussed in 2017, induced bacteria to convert ethylene and/or propylene into acetaldehyde (a primary product), ethanol (a secondary product), and acetonitrile (a product of ethanol and a subsequent ammoxidation reaction). The acetaldehyde may delay the effects of ripening and inhibit fungal growth, while the nitrile by products enhance early plant development including germination and root elongation. Experimental results suggest an inducible monooxygenase or dioxygenase like enzyme is required to facilitate this process.
Pre-Print Update. Previous studies suggested Rhodococcus rhodochrous and Bacillus licheniformis cells converted ethylene to a nitrile compound to delay the effects of ripening, (Perry, G. Nov. 9, 2017). However, there may be an alternative compound that plays a more significant role in induced Rhodococcus and Bacillus ability to delay ripening. It has been known for years that Rhodococcus can convert the alkyne compound acetylene to acetaldehyde and potentially ethanol as a secondary product (DeBont, 1980).This pre-print revisit re-examines the prior data to determine if the tri-phasic system previously discussed in 2017, induced bacteria to convert ethylene and/or propylene into acetaldehyde (a primary product), ethanol (a secondary product), and acetonitrile (a product of ethanol and a subsequent ammoxidation reaction). The acetaldehyde may delay the effects of ripening and inhibit fungal growth, while the nitrile by products enhance early plant development including germination and root elongation. Experimental results suggest an inducible monooxygenase or dioxygenase like enzyme is required to facilitate this process.Aflatoxins in Uganda: an encyclopedic review of the etiology, epidemiology, detection, quantification, exposure assessment, reduction and controlhttps://peerj.com/preprints/279632019-09-162019-09-16Timothy OmaraWinfred NassaziTom OmuteAburu AwathFortunate LakerRaymond KalukusuBashir MusauBrenda V NakabuyeSarah KagoyaGeorge OtimEddie Adupa
Uganda is predominantly an agricultural country where farming employ more than 60% of the population. Aflatoxins remain a scourge in the country, unprecedentedly reducing the value of agricultural foods and in high enough exposure levels, implicated for hepatocellular carcinoma, stunted growth in children and untimely deaths. This review synthetizes the country’s major findings in relation to the mycotoxin’s etiology, epidemiology, detection, quantification, exposure assessment, control and reduction in different matrices. It also highlights some of the management strategies for aflatoxin control that could be adopted in Uganda. Review results indicate that aflatoxins in Uganda is majorly produced by Aspergillus flavus and A. parasiticus and have been reported in maize (Zea mays L.), sorghum (Sorghum bicolor L.), sesame (Sesamum indicum), beans (Phaseolus vulgaris L.), sunflower (Helianthus annus), millet (Eleusine coracana), a bovine milk-based product, peanuts (Arachis hypogaea L.) and cassava (Manihot esculenta) with the highest content reported in cassava, beans and peanuts. The causes and proliferation of aflatoxigenic contamination of Ugandan foods have been largely due to poor pre-, peri- and post-harvest activities, poor government legislation, lack of awareness and low levels of education among farmers, agri-entreprenuers and consumers on the plague. Aflatoxin B1 is the most prevalent aflatoxin in Uganda. There is still limited research on aflatoxins in Uganda because the surveillance, reduction and control carry prohibitive costs. A few exposure assessments have been done especially in human sera and dependence on a single or a related set of foods with little diet diversity has exacerbated the risk of exposure to aflatoxins in Uganda because most of the staple foods are aflatoxin-prone. On the detection, control and reduction, these are still marginal, though some devoted scholars have devised and validated a sensitive portable device for on-site aflatoxin detection in maize as well as shown that starter cultures used for making some cereal-based beverages have the potential to bind aflatoxins. More effort should be geared towards awareness creation through training of farmers and traders in the cereal value chain as well as developing capacity to monitor aflatoxins. Vaccination against Hepatitis B and Hepatitis A should be emphasized to reduce the risk of development of liver cancer among the populace.
Uganda is predominantly an agricultural country where farming employ more than 60% of the population. Aflatoxins remain a scourge in the country, unprecedentedly reducing the value of agricultural foods and in high enough exposure levels, implicated for hepatocellular carcinoma, stunted growth in children and untimely deaths. This review synthetizes the country’s major findings in relation to the mycotoxin’s etiology, epidemiology, detection, quantification, exposure assessment, control and reduction in different matrices. It also highlights some of the management strategies for aflatoxin control that could be adopted in Uganda. Review results indicate that aflatoxins in Uganda is majorly produced by Aspergillus flavus and A. parasiticus and have been reported in maize (Zea mays L.), sorghum (Sorghum bicolor L.), sesame (Sesamum indicum), beans (Phaseolus vulgaris L.), sunflower (Helianthus annus), millet (Eleusine coracana), a bovine milk-based product, peanuts (Arachis hypogaea L.) and cassava (Manihotesculenta) with the highest content reported in cassava, beans and peanuts. The causes and proliferation of aflatoxigenic contamination of Ugandan foods have been largely due to poor pre-, peri- and post-harvest activities, poor government legislation, lack of awareness and low levels of education among farmers, agri-entreprenuers and consumers on the plague. Aflatoxin B1 is the most prevalent aflatoxin in Uganda. There is still limited research on aflatoxins in Uganda because the surveillance, reduction and control carry prohibitive costs. A few exposure assessments have been done especially in human sera and dependence on a single or a related set of foods with little diet diversity has exacerbated the risk of exposure to aflatoxins in Uganda because most of the staple foods are aflatoxin-prone. On the detection, control and reduction, these are still marginal, though some devoted scholars have devised and validated a sensitive portable device for on-site aflatoxin detection in maize as well as shown that starter cultures used for making some cereal-based beverages have the potential to bind aflatoxins. More effort should be geared towards awareness creation through training of farmers and traders in the cereal value chain as well as developing capacity to monitor aflatoxins. Vaccination against Hepatitis B and Hepatitis A should be emphasized to reduce the risk of development of liver cancer among the populace.Antibiosis effects of rice carrying Bph14 and Bph15 on the brown planthopper, Nilaparvata lugenshttps://peerj.com/preprints/279602019-09-142019-09-14Liangmiao QiuWuqi WangLongqing ShiQiquan LiuZhixiong Zhan
The brown planthopper (BPH), Nilaparvata lugens, is the most destructive insect pest in rice production worldwide. The development and cultivation of BPH-resistant varieties is the most economical and efficient strategy to overcome the destruction caused by BPH. In this study, the modified bulk seedling test method was used to identify the BPH resistance level and host feeding choice of rice lines of Liangyou8676 (Bph14/Bph15), Bph68S (Bph14/Bph15), RHT (Bph3), Fuhui676, and TN1 on BPH. Meanwhile, the population, survival and emergence rate, developmental duration, honeydew excretion, female ratio and brachyptery ratio of adults were used as indicators to detect the antibiosis effects of the different rice lines. The results showed that the resistance levels of Rathu Heenati (RHT), Bph68S, Liangyou8676, Fuhui676, and TN1 to BPH were HR, R, MR, S and HS, respectively. The host choice implied that BPH was more inclined to feeding on rice plants with a lower resistance. An analysis of the antibiosis activity of rice lines RHT, BPh68S, and Liangyou8676 carrying resistance genes indicated a significant reduction in the population growth rate, survival and emergence rate of BPH nymphs, significant delay in the developmental duration of nymphs, reduced honeydew excretion of females, decreased female ratio, and a decreased brachyptery ratio of females and males, when compared with rice carrying no BPH-resistant genes.
The brown planthopper (BPH), Nilaparvata lugens, is the most destructive insect pest in rice production worldwide. The development and cultivation of BPH-resistant varieties is the most economical and efficient strategy to overcome the destruction caused by BPH. In this study, the modified bulk seedling test method was used to identify the BPH resistance level and host feeding choice of rice lines of Liangyou8676 (Bph14/Bph15), Bph68S (Bph14/Bph15), RHT (Bph3), Fuhui676, and TN1 on BPH. Meanwhile, the population, survival and emergence rate, developmental duration, honeydew excretion, female ratio and brachyptery ratio of adults were used as indicators to detect the antibiosis effects of the different rice lines. The results showed that the resistance levels of Rathu Heenati (RHT), Bph68S, Liangyou8676, Fuhui676, and TN1 to BPH were HR, R, MR, S and HS, respectively. The host choice implied that BPH was more inclined to feeding on rice plants with a lower resistance. An analysis of the antibiosis activity of rice lines RHT, BPh68S, and Liangyou8676 carrying resistance genes indicated a significant reduction in the population growth rate, survival and emergence rate of BPH nymphs, significant delay in the developmental duration of nymphs, reduced honeydew excretion of females, decreased female ratio, and a decreased brachyptery ratio of females and males, when compared with rice carrying no BPH-resistant genes.Bovine tuberculosis breakdown duration in cattle herds: an investigation of herd, host, pathogen and wildlife risk factorshttps://peerj.com/preprints/279552019-09-112019-09-11Georgina MilneAdrian AllenJordon GrahamAngela Lahuerta-MarinCarl McCormickEleanor PreshoNeil ReidRobin SkuceAndrew W Byrne
Background. Despite rigorous controls placed on herds which disclose antemortem test positive cattle to bovine tuberculosis, caused by the infection of Mycobacterium bovis, many herds in Northern Ireland (NI) experience prolonged breakdowns. These herds represent a considerable administrative and financial burden to the State and farming community.
Methods. A retrospective observational study was conducted to better understand the factors associated with breakdown duration, which was modelled using both negative binomial and ordinal regression approaches. Six explanatory variables were important predictors of breakdown length in both models; herd size, the number of reactors testing positive in the initial SICCT test, the presence of a lesioned animal at routine slaughter (LRS), the count of M. bovis genotypes during the breakdown (MLVA richness), the local herd-level bTB prevalence, and the presence of herds linked via management factors (associated herds).
Results. We report that between 2008 and 2014, mean breakdown duration in NI was 226 days (approx. seven months; median; 188 days). In the same period, however, more than 6% of herds in the region remained under movement restriction for more than 420 days (13 months); almost twice as long as the mean. The MLVA richness variable was a particularly important predictor of breakdown duration. We contend that this variable primarily represents a proxy for beef fattening herds, which can operate by purchasing cattle and selling animals straight to slaughter, despite prolonged trading restrictions. For other herd types, the model supports the hypothesis that prolonged breakdowns are a function of both residual infection within the herd, and infection from the environment (e.g. infected wildlife, contiguous herds and/or a contaminated environment). The impact of badger density on breakdown duration was assessed by including data on main sett (burrow) density. Whilst a positive association was observed in the univariate analysis, confounding with other variables means that the contribution of badgers to prolonged breakdowns was not clear from our study. We do not fully reject the hypothesis that badgers are implicated in prolonging bTB breakdowns via spillback infection, but given our results, we posit that increased disease risk from badgers is unlikely to simply be a function of increasing badger density measured using sett metrics.
Background. Despite rigorous controls placed on herds which disclose antemortem test positive cattle to bovine tuberculosis, caused by the infection of Mycobacterium bovis, many herds in Northern Ireland (NI) experience prolonged breakdowns. These herds represent a considerable administrative and financial burden to the State and farming community.Methods. A retrospective observational study was conducted to better understand the factors associated with breakdown duration, which was modelled using both negative binomial and ordinal regression approaches. Six explanatory variables were important predictors of breakdown length in both models; herd size, the number of reactors testing positive in the initial SICCT test, the presence of a lesioned animal at routine slaughter (LRS), the count of M. bovis genotypes during the breakdown (MLVA richness), the local herd-level bTB prevalence, and the presence of herds linked via management factors (associated herds).Results. We report that between 2008 and 2014, mean breakdown duration in NI was 226 days (approx. seven months; median; 188 days). In the same period, however, more than 6% of herds in the region remained under movement restriction for more than 420 days (13 months); almost twice as long as the mean. The MLVA richness variable was a particularly important predictor of breakdown duration. We contend that this variable primarily represents a proxy for beef fattening herds, which can operate by purchasing cattle and selling animals straight to slaughter, despite prolonged trading restrictions. For other herd types, the model supports the hypothesis that prolonged breakdowns are a function of both residual infection within the herd, and infection from the environment (e.g. infected wildlife, contiguous herds and/or a contaminated environment). The impact of badger density on breakdown duration was assessed by including data on main sett (burrow) density. Whilst a positive association was observed in the univariate analysis, confounding with other variables means that the contribution of badgers to prolonged breakdowns was not clear from our study. We do not fully reject the hypothesis that badgers are implicated in prolonging bTB breakdowns via spillback infection, but given our results, we posit that increased disease risk from badgers is unlikely to simply be a function of increasing badger density measured using sett metrics.