Screening rhizobacteria for biological control of Fusarium root and crown rot of sorghum in Ethiopia

Fusarium oxysporum Schlectend causes root and crown rot in several crops including sorghum that results in low grain yield in Ethiopia and other East African countries. Seventy-eight bacterial isolates were obtained and subsequently tested both in vitro and in the greenhouse. Of the 78 isolates tested, 23 displayed between 30 and 66.3% inhibition of in vitro mycelial growth of F. oxysporum and also showed significant root colonization ability on sorghum seedlings. These isolates were further tested for their biocontrol ability against F. oxysporum in the greenhouse. Four isolates viz. KBE5-7, KBE5-1, KBE2-5 and NAE5-5 resulted in 100% disease suppression and no symptoms of root and crown rot were observed compared to the control. The complete suppression of F. oxysporum by these isolates was also confirmed by root plating on Fusarium-selective medium. The most effective isolates were identified by means of the API system as members of the Genus Bacillus including B. cereus, B. subtilis, B. circulans, B. licheniformis and B. stearothermophilus. Two other isolates, which colonized the sorghum rhizosphere and resulted in more than 70% disease suppression, have been identified as Chromobacterium violaceum. The study demonstrated effective biological control by the rhizobacterial isolates tested, thereby indicating the possibility of application of rhizobacteria for control of soilborne diseases of sorghum in Ethiopia and other countries

Phosphorus sorption capacity as a guide for phosphorus availability of selected Sudanese soil series

Crop response to phosphorus application is often erratic in most soil types in Sudan. This inconsistent response is believed to be due to the alkaline nature of most soils in the country. Phosphorus adsorption isotherms and buffering capacity are powerful tools for predicting response of different soil types to apply P fertilisers. This study was carried out to investigate the degree of P adsorption capacity in some soils in Sudan and the consequential effect on P availability. A laboratory experiment was conducted on six soil samples of selected soil series from different sites in Sudan. Samples were equilibrated with different P concentrations, prior to evaluating the sorption potential and binding intensity. Results indicated that at any specific P concentration, the amount of P sorbed by the Entisols was higher than for the other soils. The order of soils according to their adsorption capacities using Freundlich equation were 917, 330, 315, 269, 214 and 80 mg P kg-1 soil for River Nile banks (Entisols), Dongola 2 (Aridisols), Permanent Fallow (Virgin Vertisols), Remitab (Cultivated Vertisols), Khashm elgirba (Vertisols) and Dongola1 (Aridisols), respectively. The soil\u2019s ability to sorb added P increases due to increase in affinity sites of clay and iron content.La r\ue9ponse des cultures \ue0 l\u2019application du phosphore est souvent impr\ue9dictible dans beaucoup de types de sols du Sudan suite \ue0 la nature alkaline de laplupart des sols dans ce pays. Les isothermes d\u2019adsorption du phosphore et la capacit\ue9 tampon sont des outils les plus efficaces pour pr\ue9dire la r\ue9ponse de diff\ue9rents types de sols \ue0 l\u2019application des engrais phosphat\ue9s. Cette \ue9tude \ue9tait conduite pour \ue9valuer la capacit\ue9 d\u2019adsorption du phosphore dans quelques sols du Sudan et ses effets sur le phosphore disponible. Un essai au laboratoire \ue9tait conduit sur six \ue9chantillons de sol s\ue9lectionn\ue9s des s\ue9ries de diff\ue9rent sites au Sudan. Ces \ue9chantillons \ue9taient \ue9quilibr\ue9s avec diff\ue9rentes concentrations de P avant l\u2019\ue9valuation du potentiel d\u2019adsorption et l\u2019intensit\ue9 d\u2019adh\ue9sion. Les r\ue9sultats ont indiqu\ue9 qu\u2019\ue0 une certaine concentration sp\ue9cifique de P, la quantit\ue9 de P fix\ue9 par les Entisols \ue9tait plus \ue9lev\ue9e que celle des autres sols. Sur base de l\u2019Equation de Freundlich, l\u2019ordre de sols en rapport avec leur capacit\ue9 d\u2019adsorption \ue9tait de 917, 330, 315, 269, 214 et 80 mg P kg-1 de soil pour les bordures de la rivi\ue8re Nile (Entisols), Dongola 2 (Aridisols), la jach\ue8re permanante (Vertisols vierge), Remitab (Vertisols cultiv\ue9s), Khashm elgirba (Vertisols) et Dongola 1 (Aridisols), respectivement. La capacit\ue9 du sol \ue0 fixer P augmente suite \ue0 l\u2019augmentation des sites d\u2019affinit\ue9 d\u2019argile et de la teneur en fer

The effects of SRT, OLR and feed temperature on the performance of membrane bioreactor treating high strength municipal wastewater.

The effects, of sludge retention time (SRT), feed temperature (Tf) and organic loading rate (OLR) on submerged membrane bioreactor (SMBR) performance were studied using hollow fibers (nominal pore size 0.4 µm) immersed in an aeration tank. A synthetic wastewater representative of high strength municipal wastewater was used in the study. Ten experimental runs were carried out using full factorial design with three factors and three levels (low, medium and high). These levels were 25, 30 and 35 days for SRT, 20, 30 and 40°C for Tf and 1.73, 4.03 and 6.82 kg COD/m³ d for OLR. Variation of OLR, SRT and Tf affected the biomass development significantly. The higher OLR trials resulted in higher MLVSS/MLSS ratio and also higher increasing rate of MLSS (d(MLSS)/ (dt)). For the low level OLR trials MLVSS/MLSS ratio varied between 75.3 and 82.3% and d(MLSS)/(dt) from 87.5 to 297.3 mg/l.d, whereas, for the high OLR trials they varied between 80.4 and 83.7% and 1355.4-2120.1 mg/l.d respectively. For the higher OLR, a higher aeration rate was applied to fulfill the DO demand. Therefore, for the low level OLR trials, the aeration rate and the DO were varied from 6 to 12 m³/m² membrane area per hour and from 3.7 to 5.7 mg/l, respectively, whilst for the high OLR trials they varied from 6 to 18 m³/m² membrane area/h and from 0.9 to 4.4 mg/l respectively. The permeate COD and NH3-N under different operating conditions varied from 0 to 32 mg/l, and from 0.004 to 0.856 mg/l, respectively. The interaction effects of SRT and Tf on COD removal efficiency was found to be insignificant. Increasing OLR did not affect COD removal. The optimum removal efficiency of ammonia nitrogen for the low and high strength wastewater was obtained at operating conditions of high SRT and low Tf. The pH increased significantly in the aeration tank and the increase was well correlated with the feed pH (r² = 0.8336 for low OLR and 0.9106 for high OLR)

Membrane fouling in a submerged membrane bioreactor treating high strength municipal wastewater

Studying the influence of the operating parameters on membrane fouling is important in fouling control. This paper presents the interaction effects of the sludge retention time (SRT), organic loading rate (OLR) and feed temperature (Tf) on membrane fouling. A submerged membrane bioreactor (SMBR) was operated under a constant flux (11.1 l/m2 h), with different SRT, Tf and OLR. A synthetic wastewater representative of high strength municipal wastewater was fed to the bioreactor. Three different levels (low, medium and high) of SRT, Tf and OLR were studied. These were 25, 30 and 35 days for SRT, 20, 30 and 40°C for Tf and OLR of 1.73, 4.03 6.82 kg COD/m3.d. The sustainable time (tsus) was defined as the time at which the rate of suction pressure started to increase rapidly. tsus was found to increase with low SRT and high Tf. A higher OLR resulted in higher mixed liquor suspended solids (MLSS), however it did not cause a faster membrane fouling. Applying higher aeration rate enabled a longer sustainable time to be obtained. Sustainable time tsus was found to be well correlated with MLVSS/MLSS with an r2 of 0.995. The range of MLVSS/MLSS tested varied from 74.3 to 82.3% at which tsus decreased 2.9-fold (from 175 to 60.5 h)

Paratuberculosis: The Hidden Killer of Small Ruminants

Paratuberculosis (PTB) is a contagious and chronic enteric disease of ruminants and many non-ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), and is characterised by diarrhoea and progressive emaciation with consequent serious economic losses due to death, early culling, and reduced productivity. In addition, indirect economic losses may arise from trade restrictions. Besides being a production limiting disease, PTB is a potential zoonosis; MAP has been isolated from Crohn’s disease patients and was associated with other human diseases, such as rheumatoid arthritis, Hashimoto’s thyroiditis, Type 1 diabetes, and multiple sclerosis. Paratuberculosis in sheep and goats may be globally distributed though information on the prevalence and economic impact in many developing countries seem to be scanty. Goats are more susceptible to infection than sheep and both species are likely to develop the clinical disease. Ingestion of feed and water contaminated with faeces of MAP-positive animals is the common route of infection, which then spreads horizontally and vertically. In African countries, PTB has been described as a “neglected disease”, and in small ruminants, which support the livelihood of people in rural areas and poor communities, the disease was rarely reported. Prevention and control of small ruminants’ PTB is difficult because diagnostic assays demonstrate poor sensitivity early in the disease process, in addition to the difficulties in identifying subclinically infected animals. Further studies are needed to provide more insight on molecular epidemiology, transmission, and impact on other animals or humans, socio-economic aspects, prevention and control of small ruminant PTB

Everything is going electronic, so do services and service quality: bibliometric analysis of e-services and e-service quality

Purpose: The purpose of the study was to explore the developments in ‘e-services and e-service quality' from 2000 to 2020. Data Source: Scopus database was used to conduct the bibliometric analysis of 404 documents. Method: VOSviewer software was used to analyse the research articles associated with ‘e-services and e-service quality' research. Search was limited to keywords of ‘e-services OR e-service and e-service quality'. Findings: Results revealed that the field of ‘Business, Management and Accounting' had the highest number of publications. Total Quality Management and Business Excellence was found at the top among the most productive journals in chosen search. Chang W.-I. and Yuan S.-T. from Taiwan were found to be the leading authors among top ten authors. United States and National Cheng Kung University of Taiwan were found to be the leading country and institution in the selected search of e-service and e-service quality. Originality/Value: This study, to best of our knowledge, is the first of its kind in mapping the ‘e-services and e-service quality' literature in Scopus. This will aid in shaping the central theme and set the future research directions for the researchers

Optimizing Compressive Strength Properties of Binary Blended Cement Rice Husk Concrete for Road Pavement

Different supplementary cementitious materials are often blended with cement to produce sustainable concrete. More often than not, the strength of blended concrete is compromised, if the constituent materials are not carefully selected. In this study, optimization of strength properties of blended cement-rice husk ash (RHA) was carried out to determine the best mix ratio that produced binary blended concrete of high strength. Different mix ratios of cement and RHA were studied at a water cement ratio of 0.4 to produce concrete specimens. RHA was produced by burning 700 ℃ for an hour and its chemical composition was determined using the X-Ray Fluoresce (XRF) technique. RHA produced was used to replace cement at replacement levels of 2.5, 5, 7.5, and 10 %, and was used as binder. The compressive strength of each concrete mix was determined at 7, 28, and 56 days. Approximately 250 concrete cubes were tested and the results were subjected to statistical analysis. The results showed that compressive strength and internal structure varied with RHA as a replacement for cement. Optimal strength was achieved for a concrete mixture, prepared at a water: cement: aggregate ratio of 1:1.5:3, respectively, and a RHA replacement ratio of 5 %. HIGHLIGHTS Cement is the most utilized construction material. The energy-intensive processes that are involved in its production contribute up to 10 % of total global CO2emissions, with potentially adverse environmental implications. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising supplementary cementitious materials (SCMs) or pozzolans Currently, most sustainable concrete uses either GGBS (slag) or PFA (fly ash) to reduce the quantity of cement used in construction and highways applications. GGBS and PFA come from industries (steel and coal waste respectively) which are in decline that should not be relied upon in the long term. Therefore, for long term sustainability it is imperative to focus attention on other alternative pozzolans This report shows that cement in concrete can also be replaced with rice husk ash (RHA) which actually enhances the mechanical properties. Findings show the usage of up to 5 % rice husk ash as a partial cement replacement can enhance the strength of concrete whilst reducing the embodied CO

Seroprevalence of Mycobacterium avium subsp. paratuberculosis in Dairy Cattle in Khartoum State, Sudan

Paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic wasting disease mainly of domestic and wild ruminants. It occurs worldwide, causing significant economic losses through decreased productivity, low fertility, increased cull rates and mortality. It is listed by the OIE (World Organization for Animal Health) as a disease of concern to trade in animals. Prevalence of this disease can be studied by detecting anti-MAP antibodies by Enzyme linked immunosorbent Assay (ELISA). The aim of this study was to investigate the current prevalence of MAP infection in cattle in Khartoum State. The overall apparent prevalence of MAP infection was found to be 6.3% and 18.9% at animal and herd levels, respectively. All seropositive animals were cross-bred females of good body condition; most of them (>90%) were >3 years old and >50% were from medium-sized herds in Omdurman. No significant association (p > 0.05) was found between seropositivity and animal herd size. The prevalence of MAP infection in Khartoum State is still low to medium compared to other parts of the world, but it is comparable to those reported from other African countries. Further studies with the view of designing nationwide surveys in domestic ruminants and camels in other states of the country are needed for establishing control programmes

Evaluation of safe attenuated vibrio alginolyticus for oral vaccination of lates calcarifer against vibriosis.

Safe attenuation has been done on marine pathogen Vibrio alginolyticus using naturally acidified fructose against vibriosis. Attenuation was confirmed by injecting the attenuated bacterium into fish where the survival rate was 100% compared to 50% survival in fish injected with non-attenuated bacteria. The attenuated bacterium was then evaluated for oral vaccination of Lates calcarifer (Asian seabass). Fish were fed with fish pellet incorporated with attenuated and non-attenuated bacterium of V. alginolyticus for 30 days. They were measured for serum antibody production by conventional agglutination titer and also monitored for the fish weight gain to observe the health improvement. Vaccinated fish showed comparable increased in weight gain, 90% survival after challenge and significantly high antibody titer compared to other treatment and control

Responses of haptoglobin and serum amyloid A in goats inoculated intradermally with C. pseudotuberculosis and mycolic acid extract immunogen

Haptoglobin (Hp) and Serum Amyloid A (SAA) are a group of blood proteins whose concentrations in animals can be influenced by infection, inflammation, surgical trauma or stress. Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), and Mycolic acid is a virulent factor extracted from C. pseudotuberculosis. There is a dearth of sufficient evidence on the clinical implication of MAs on the responses of Hp and SAA in goats. Therefore, this study was conducted to evaluate the potential effects of Mycolic acid (MAs) and C. pseudotuberculosis on the responses of Hp and SAA in female goats. A total of 12 healthy female goats was divided into three groups; A, B and C each comprising of 4 goats and managed for a period of three months. Group (A) was inoculated with 2 mL of sterile phosphate buffered saline (as a negative control group) intradermally, while group (B) and (C) were inoculated intradermally with 2 ml each of mycolic acid and 1‏ × 109 cfu of active C. pseudotuberculosis respectively. The result of the study showed that the Hp concentration in goats inoculated with C. pseudotuberculosis was significantly increased up to 7-fold (1.17 ± 0.17 ng/L) while MAs showed a 3-fold increased (0.83 ± 0.01 ng/L) compared with the control. Whereas SAA concentration in C. pseudotuberculosis and MAs groups showed a significant 3-fold (17.85 ± 0.91 pg/mL) and 2-fold (10.97 ± 0.71 pg/mL) increased compared with the control. This study concludes that inoculation of C. pseudotuberculosis and MAs have significant effects on Hp and SAA levels, which indicates that MAs could have a role in the pathogenesis of caseous lymphadenitis