Recent Advances in Biological Research Vol. 2

Soil Bacteria as a Natural Source of Antifungal Agents against Phytopathogenic Fungus: Aspergillus niger

A. P. Rao, B. E. Agbo, N. S. Udoekong, H. A. Etuk — Tue, 02 Jul 2019 00:00:00 +0000

Soil bacteria are able to synthesize a wide range of metabolites with fungicidal activity. Nine bacterial isolates were obtained from the botanical garden of University of Calabar. Preliminary examination of isolates was carried out using morphological characteristics and biochemical analysis. These isolates were designated with codes SB1, SB2, SB3, SB4, SB5, SB6, SB7, and SB8. Bacterial isolates were evaluated for their potentials of antagonism against Aspergillus niger isolated from spoiled vegetables like tomatoes by using agar diffusion technique. Percentage inhibition of mycelial growth by these isolates recorded values as 27%, 0%, 66%, 40%, 97%, 0% and 23% respectively. Isolates were analyzed through several biochemical tests and were identified as Bacillus sp., Enterobacter spp., Pseudomonas spp., Proteus spp., Escherichia coli, Streptococcus spp. and Staphylococcus spp. respectively. These result indicated that bacterial species exhibited varying degree of antagonism against the fungus Aspergillus niger. Escherichia coli showed maximum inhibitory potential against tested fungus with reduction of up to 97% in their mycelial fungal growth, followed by Pseudomonas spp. and Bacillus spp. with 66.7% reduction. From the results obtained, it is found that the bacterial species isolated from the soil samples are effective as antifungal agents against phyto-pathogenic fungi. Escherichia coli, Pseudomonas spp., Bacillus spp. had more antagonistic effect on vegetative growth of tested fungi (Aspergillus niger). These bacterial species showed higher levels of inhibitory effect on fungal spore germination. The presented data exhibit the antifungal activity of bacterial species and indicate the possibility of using these bacterial species as a biological agent to control the phyto pathogenic fungi.

Comparative Antimicrobial Activities of Solvent Extracts and Silver Nanoparticles Synthesized from Seeds of Areca catechu L.

P. Rama Bhat, V. H. Savitri — Tue, 02 Jul 2019 00:00:00 +0000

The present study was carried out to screen phytochemicals like carbohydrates, terpenoids, resins, saponins, tannins and alkaloids in the seed extract of Areca catechu by standard protocols and antibacterial activities of seed extract as well as silver nanoparticles prepared from seed extracts. The medicinal properties of plants have been investigated in the recent scientific developments throughout the world, due to their potency against several disease, minor side effects and economic viability. Several compounds widely distributed in plants which have been reported to exert multiple biological effect, including antioxidant, free radical scavenging abilities, anti-inflammatory and anti-carcinogenic. Nanoparticles are synthesized using plant materials. The various phytochemicals present within the plant result in effective reduction of silver salts to nanoparticles. The characterization of silver nanoparticles was studied by using FTIR, SEM and UV- Visible spectrophotometer. Antibacterial activity was conducted with aqueous, methanolic and AgNO₃seed extracts against six bacterial species viz., Salmonella typhi, Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis by agar well diffusion method. The seed extract showed positive results for carbohydrate, proteins, alkaloids, glycosides, terpenoids, tannins and saponins. The colour of the solution after treating with AgNO₃was changed from light brown to dark brown confirmed the reduction of silver ion in presence of seed extract and formation of silver nanoparticles. Maximum absorption was observed at 400 nm and the size of silver nanoparticles produced was oval in shape with the diameter of 553-610 nm. Pseudomonas aeruginosa and Salmonella typhi were found to be the good organisms resistant against areca nut seed extracts while others were showed intermediate effects. This study suggest that A. catechu nut extract can be a potential source for developing antibacterial agents against Gram positive bacteria which are commonly found on human oral cavity and responsible for dental caries. This present study also supports the use of natural products for medication as antibacterial agents found in plant extract, which exhibits antibacterial activity to some opportunistic oral bacteria, we have some reservations towards the side effects that need to be studied and evaluated more thoroughly. The results highlight the traditional use of “Areca nut” and some scientific validation of the claimed biological antimicrobial activity in vivo.

Generation and Analysis of Biogas from Some Animal and Vegetable Wastes

E. A. S. Osibote, B. O. Odesanya, G. S. Soetan — Tue, 02 Jul 2019 00:00:00 +0000

The world relies heavily on fossil fuels for both domestic and commercial energy needs but there is an environmental effect of these fossil fuels and as the energy consumption is becoming very significant as there is depletion of the fossil fuels. Research has to be in the development of alternative energy sources. The production of biogas plays an important role in reducing greenhouse gases emissions and facilitates a sustainable development of energy supply. The process of production only uses energy from renewable energy sources. Hence, no net carbon dioxide is added to the atmosphere, making it an environmentally benign energy source. One of the alternative sources of energy is bio-energy. The common fuels obtainable from biomass are bio-ethanol and biogas. This study aims at the production of biogas from biologically degradable wastes by the co-digestion system and analysing the percentage composition of CH₄ and CO₂ in biogas produced. It involves using fruit (peels and seeds of orange, tomato, cucumber) and vegetable (efo shoko-leafy vegetable) wastes mixed with pig manure in an anaerobic digester. Thus giving an alternative energy source and making the environment cleaner by reducing the green energy gases and wastes. The gas content, therefore, is analysed. The composition of CO₂ and CH₄ content in biogas generated were CO₂ 28.1% and CH₄ 68.9%. Biogas-generating technology is a favourable dual-purpose technology at present: the biogas generated can be used to meet energy requirements while the organic residue is a useful fertiliser.

Phytochemical screening, proximate analysis of the fruit waste, vegetable waste and the pig waste were carried out. The proximate analyses were carried out for carbohydrates using Anthrone method, Total Lipids Using Bligh & Dyer Method; Crude Fibre, moisture content, total ash, and crude protein method as described by AOAC (1995); The high content of the methane obtained is a high indication that the waste materials used are a good source of biogas generation and can be used to provide a cleaner environment. Investigation shows that biogas can be successfully produced from co-digestion of manure with fruits and vegetable wastes without any chemical added to the system. The quality of methane composition in biogas and quantity of biogas produced depends on the composition of materials fed to the digester, fat and moisture content is important in methane yield. Through anaerobic digestion of fruit and vegetable wastes, one can avoid the emission of harmful greenhouse gases and make a positive contribution to a cleaner environment. Production of biogas from fruit and vegetable waste and pig dung is a major step toward harnessing the least utilised renewable energy resource. From this work, methane gas has been produced. The CO₂ generated in the mixture can be removed. The methane content is high, no additional energy was used as the microorganisms were used in an anaerobic condition, in the generation of the biogas.

Fatty Acid Methyl Ester Analysis of Olive Oil Degraded by Pseudomonas fluorescens and Enzymatic Characterisation of the Lipase

B. M. Popoola, A. A. Onilude, T. Olateru Comfort — Tue, 02 Jul 2019 00:00:00 +0000

Vegetable oils are harmful to the environment, like petroleum oils they produce similar environmental effects. Hence, it is a known fact that the olive oil causes the production of large quantity of olive mill waste (OMWs) as by-products to the environment. These by-products are harmful to the environment, both terrestrial and aquatic. Bacteria are very useful in protecting the environment. The lipolytic activities of physiologically diverse bacteria have great potential to degrade oil spills in the environment. Fatty acids are the major components of lipids; and the physical, chemical and physiological properties of a lipid class depend primarily on its fatty acid composition. There is need for extensive characterisation of the bacterium lipase for the treatment of vegetable oil-polluted sites. This work was carried out to preliminarily characterise the lipase of Pseudomonas fluoresens and to check the fatty acid composition of olive oil. Gas chromatography method can be used for the identification of microbiological degraded fatty acids in vegetable oils as methyl ester.

Pseudomonas fluoresens was screened for lipase production using standard methods. Temperature, pH, ion concentration (NaNO₃ and MgSO₄), enzyme concentration, nitrogen concentration, substrate concentration, time course and agitation speed were optimised for the lipase activity as well as growth.

Crude enzyme of Pseudomonas fluoresens had the highest lipase activity and growth of 0.8 U/mL and 1.418 mg/mL respectively at room temperature, but when production was optimised higher activity 0.9 U/mL was seen in the use of glucose as substrate. Agitation with the speed used did not support lipase production but supported growth (1.998 mg/mL) at agitation speed of 100 rpm. Olive oil degraded by lipase of Pseudomonas fluorescens grown in two different Mineral Salt Medium, was studied over 25 days. Olive oil was analyzed for fatty acids commonly present in olive oils which are Myristic, Palmitic, Stearic, Oleic, Linoleic, Linolenic, Behenic and Lignoceric, which have specific carbon number and their values in approximate percentage are C14:0 (0.4), C16:0 (14.0), C18:0 (5.5), C18:1 (76.4), C18:2 (3.4), C18:3 (0.1), C22:0 (0.1) and C24:0 (0.1) respectively. Oleic acid percentage is high in olive oil which contained considerable amount of 76.4%.

The reduction of fatty acid by Pseudomonas fluorescens after 20 days was 8.2% in the media used. Lipase from Pseudomonas fluorescens had potential for degradation of fatty waste. It could therefore be employed in environmental cleanup of oil spill site. Lipase production is generally influenced by the type and concentration of carbon and nitrogen sources, the culture pH, the growth temperature and the dissolved oxygen concentration [1]. Hence monitoring the result of degradation patterns of the vegetable oil using fatty acid methyl ester analysis, by Pseudomonas fluorescens, showed that this organism has great potential for fatty waste degradation and as an extension in environmental clean up of oil spill site.

Comparing the Susceptibility of Chironomus Striatapennis Larvae Exposed to Heavy Metals

Susanta Nath, Rahul Podder, Biplob Kumar Modak, Sudipta Das — Tue, 02 Jul 2019 00:00:00 +0000

Fourth instar larvae of Chironomus striatapennis were collected from breeding aquarium under laboratory conditions and exposed for 96 hours to different doses of Pb, Cd and Hg for static bioassay to measure the LC₅₀. Ten fourth instar larvae were placed in 100 ml beaker with 50 ml of each test solution. Larvae were exposed to six different concentrations, consisting of five trials. A control was also maintained wherein organisms were exposed to distilled water. Larvae were not fed during the toxicity tests. All beakers were free from tube forming materials. Data of mortality were subjected to probit analysis. Chi square was used to test for heterogeneity and the result was found to be significant (p<0.05) in all three metals. Results showed that sensitivity of larvae to metals was Hg> Cd >Pb. C. striatapennis showed noticeable response in LC₅₀ study and was sensitive to low doses of heavy metals. Several secondary consumers have preferred this larva as their food. So unplanned industrialization may increase the level of heavy metals in the aquatic ecosystem which will accumulate slowly but definitely in different trophic levels and at the same time unusual death of these larvae may indirectly change the equilibrium of the aquatic ecosystem. Static bioassay of heavy metals revealed that larvae of Chironomus striatapennis was more sensitive to Hg than Cd and Pb respectively. It was also observed that LC₅₀ values were less than standard permissible limit of these heavy metals. Unplanned industrialization may increase the level of heavy metals in the aquatic ecosystem which will accumulate slowly but steadily in different trophic levels and at the same time unusual death of these larvae may indirectly change the equilibrium of the aquatic ecosystem. As this larva is a preferred food for different secondary consumers, heavy metal toxicity may responsible for bio-accumulation of several heavy metals in chironomid larvae and make these larvae unsuitable for consumption.

Physicochemical Properties of an Avian Protease Inhibitor

Khushtar Anwar Salman, Sharique Ahmed, Indu Saxena — Tue, 02 Jul 2019 00:00:00 +0000

Background: Ovomucoid is a serine proteinase inhibitor in the egg whites of all avian species at a concentration of about 10 mg/ml. The involvement of proteinases in a multitude of control functions in an organism has created an interest in their physiological inhibitors. Regulation of proteolytic activity in tissues is a critical requirement in the maintenance of homeostasis. Egg white proteins possess ACE-inhibitory activity & high radical-scavenging activity. The combined antioxidant and ACE-inhibitory properties of egg white hydrolysates, or the corresponding peptides would make a useful multifunctional preparation for the control of cardiovascular diseases. Proteases play key roles in several physiological processes, including intracellular protein degradation, bone remodeling, and antigen presentation, and their activities are increased in pathophysiological conditions such as, cancer metastasis and inflammation. They are also required for invasion by the microorganism. Four protease inhibitors have been identified in egg white namely, cystatin, ovomucoid, ovomacroglobulin (also known as ovostatin), and ovoinhibitor. Use of proteinase inhibitors in the treatment of certain diseases has renewed interest in their specificity and stability, both of which in turn depend on the tertiary structure of the inhibitor. Structural alteration to obtain molecules of desired properties requires knowledge of relationship between structure, function and stability.

Aims: Given its importance, in the present study duck ovomucoid was isolated and characterized for its physicochemical properties.

Methodology: Duck ovomucoid was isolated and characterized by its physicochemical properties. Analytical gel filtration (Sephacryl S-100 HR column) was used for purification, determination of molecular weight (MW), carbohydrate content and Stokes radius.

Results & Conclusion: The fluorescence emission spectrum was 302 nm, comparable to earlier reports. Stoke’s radius was found to be 2.91nm, and the value was comparable with white leghorn hen (Stoke’s radius 3.15nm). The extraordinary large value of stokes radius can be attributed to its high carbohydrate content which increases the hydration of the molecule. The inhibitor had the molecular weight of 29,300, and the carbohydrate content was 22%, the specific extinction coefficient of duck ovomucoid was found to be 5.82 at 279 nm and the Stoke’s radius was 2.91nm. The extraordinary large value of stokes’ radius of duck ovomucoid can be attributed to its high carbohydrate content which increases the hydration of the molecule resulting in large Stoke’s radius. Further functional studies on duck ovomucoid are required, as it has been reported that the chicken ovomucoid hydrosylates have some exceptional antioxidant, ACE inhibitory and metal chelating activities.

Synthetic Elicitor-Induced Defense Responses in Tomato (Solanum lycopersicum) Cultivated in Côte d'Ivoire against Bacterial Wilt Caused by Ralstonia solanacearum

Tue, 02 Jul 2019 00:00:00 +0000

Tomato is the most consumed vegetable in Côte d’Ivoire because it is used to cook most sauces and all forms of salad. Tomatoes annual yield fluctuates between 22,000 and 35,000 tons. The yield remains below demand. Several factors can explain these low yields. Among them, biotic factors are the most important. Among bacterial diseases impacting negatively tomato yield, bacterial wilt caused by Ralstonia solanacearum is a dangerous one that causes serious damage in the nursery as well as in plantation. It can cause up to 100% yield loss depending on the variety. Bacterial wilt caused by Ralstonia solanacearum still constitutes tomato (Solanum lycopersicum) economical disease in the world. This disease is favored by very humid soils and high temperatures. Genetic control currently used is the most effective strategy. Disease control in crops has also become possible through the induction of plant defense reaction. This work aims at assessing the effect of both synthetic elicitors (BABA and ASM) supposed to induce tomato defense reaction against bacteria and particularly Ralstonia solanacearum. BABA and ASM solutions were each applied at concentrations of 5 to 100 ppm on R. solanacearum in vitro, and its growth was recorded. Then, the in vivo development of bacterial wilt was assessed following different elicitors application modes to both local tomato cultivars Tropimech and Caraïbo respectively sensitive and tolerant to this disease. Up to 100 ppm, BABA and ASM elicitors showed no antibacterial effect against R. solanacearum. However, these elicitors revealed a protective action against the development of bacterial wilt after inoculation of R. solanacearum. Compared to leaf treatment, the supply of elicitors to roots or successively to roots and leaves reduced the development of bacterial wilt by more than 50%. Both tomato varieties (Tropimech and Caraibo) expressed identical resistance levels facing Ralstonia solanacearum after BABA and ASM application. The elicitation of tomato plants could be an ecological approach for effective control of R. solanacearum. It is concluded that control bacterial wilt caused by R. solanacearum using ASM and BABA as elicitors of tomato defense. Two tomato cultivars that are Tropimech and Caraïbo respectively sensitive and tolerant to bacterial wilt were used. Tropimech which is the sensitive cultivar expressed identical resistance levels facing Ralstonia solanacearum after BABA or ASM application as Caraibo, the tolerant cultivar. Thus, ASM and BABA can be used in control to bacterial wilt of tomato. This technique can be considered as an ecological approach and an alternative to chemical control of bacterial wilt caused by R. solanacearum in tomato.

Antibiotics Susceptibility Pattern of Methicillin Resistant Staphylococcus aureus (MRSA) in Enugu State, South-East Region of Nigeria

A. A. Agboke, A. A. Attama — Tue, 02 Jul 2019 00:00:00 +0000

Development of antimicrobial resistance by bacteria is now a worldwide health issue, as infection is one of the leading causes of death in the world today. The aim of this study was to evaluate the prevalence and antimicrobials susceptibility pattern of Methicilin-Resistant Staphylococcus aureus in 3 different hospitals in South-East geopolitical region of Nigeria. The identification and confirmation of the S. aureus were done using selective and differential medium (Mannitol salt agar) for S. aureus and by coagulase/staphylase test using Oxoid^®reagents kits (DR0595A). The method used for antibiotics susceptibility pattern of the characterised S. aureus isolates was discs diffusion method, as recommended by the Clinical Laboratory Standards Institute (CLSI), discs containing oxacillin (5 µg/disc), vancomycin (30 µg/disc), cephalexin (30 µg/disc), levofloxacin (5 µg/disc), ciprofloxacin (5 µg/disc), tetracycline (30 µg/disc), cotrimoxazole (25 µg/disc), gentamicin (30 µg/disc), clindamycin (2 µg/disc) and rifampicin (5 µg/disc). MRSA confirmation was done using Oxoid^® DR0900 penicillin binding protein (pbp2^’) latex agglutination test kits. The results showed that out of 218 characterized clinical isolates, 39 of it were confirmed MRSA with varying percentages of resistance to various antibiotics thus: oxacillin (62.07%), vancomycin (60.35%), cephalexin (55.18%), levofloxacin (56.90%), ciprofloxacin (65.52%), tetracycline (68.97%), cotrimoxazole (67.25%), gentamicin (62.07%), clindamycin (63.79%) and rifampicin (62.07%). The S. aureus are more sensitive to Levofloxacin and less sensitive to tetracycline, clindamycin and rimfapicin. Latex agglutination test confirmed 39 strains of the clinical isolates to be MRSA. The results shows open wound as a source with highest prevalence and sputum with lowest prevalence of the MRSA with no significant change (P > 0.05).

Keratin Degradation by Penicillium purpurogenum and Aspergillus niger Isolated from Nigerian Soils Polluted with Tannery Wastes

A. I. Ogbonna — Tue, 02 Jul 2019 00:00:00 +0000

Background: Keratinophilic fungi are a group of fungi that colonize various keratinous substrates and degrade them to components of low molecular weight. Keratinized tissues include feathers, beaks of birds, horns, hooves, skins, hair, fur, wool, nails and claws of animals. Tannery soils are very rich in keratinous materials such as fur, wool and hair that are by-products of the tanning industry where hides and skins are processed. Keratinase producing fungi, Aspergillus niger and Penicillium purpurogenum were isolated from soils containing tannery wastes in Jos, Plateau State Nigeria.

Materials and Methods: Skim milk casein agar was employed to assay for extra cellular protease as an indication for keratinase production. The species had maximum proteolytic and keratinase activities in a Submerged Fermentation (SmF) using liquid basal medium supplemented with skim milk, chicken feathers and human hair as carbon and nitrogen sources. Effects of incubation temperature on protease and keratinase enzyme activity were also determined.

Results: The Spectrophotometric assay of the proteolytic and keratinolytic activity showed that P. purpurogenum had the highest activity (13.5 U/ml) on chicken feathers. This was followed by human hair with activity of 12 U/ml. The least activity of 11.9 U/ml was observed in skim milk medium. Similar results were recorded for A. niger with highest activity of 11.8 U/ml on chicken feathers. This was followed by human hair with activity of 10.6 U/ml while skim milk agar had the least activity of 10.0 U/ml. It was observed that incubation temperature had effects on the enzyme activity, with an optimum temperature of 37°C for both protease and keratinase.

Conclusion: These non-dermatophytic keratinolytic fungi may have potential use in biotechnological processes involving keratin hydrolysis. The results of this work reiterated that keratinolytic activity is relatively widespread among common fungi and may have an important role in keratin degradation in the natural environment. P. purpurogenum and A. niger bio-degraded skim milk casein, human hair and chicken feather in Submerged Fermentation (SmF). They had the greatest activity on chicken feathers indicating that they could be employed in waste and environmental pollution management. In Nigeria, poultry feathers, animal hair and other keratin sources including tannery wastes do not find suitable applications. Practical use of keratinase producing microorganisms such as the ones used in this study is being explored in applied microbiology where there is great need for active degraders for the management of keratin containing wastes.

Copper Nanomaterials as Delivery System in Combating Infective Agents and Cancer

Ardhendu Kumar Mandal — Tue, 02 Jul 2019 00:00:00 +0000

Infectious diseases portend serious threat hazards to public health globally due to the development of the resistance to broad spectrum antimicrobials, the emergence of multidrug resistant biofilms, the drug side-toxicity, the non-specificity of drug targeting and the inability to overcome biological barriers. In this context, nanotechnology-based metal nanoparticles have attracted attention as nanomedicine against different diseases for their additional capability to anchore other therapeutic contents effectively for delivery. Owing to the large surface area to volume ratio, copper nanomaterials have been utilized as potential anti-infective and anticarcinogenic agent in biomedical applications. Though their higher significant efficiencies in damaging pathogenic cells have been elucidated, their nano-metallic toxicity increases other side-toxicity to healthy cells. Therefore, copper, copper oxide and copper sulfide -nanoparticles should be surface functionalized with ligands and vesicular system to reduce the toxic side effect for delivering to specific site of interest in a sustained-release manner. The subject has been focused mainly on the synthesis, size and surface characteristics, mechanism of action and biomedical applications of copper nanomaterials in damaging various infective agents and cancer cells as probable potent drug delivery system.

Chemical Composition of Myrtus communis L. (Myrtaceae) Fruits

Karzan Omer Qader, Sahar A. A. Malik Al-Saadi, Thuraya A. Al-Saadi — Tue, 02 Jul 2019 00:00:00 +0000

The chemical composition of Myrtus communis L. extracts were prepared and analyzed by GC-MS. Sixteen phytochemical constituents of chemical compounds were identified in fruits of Myrtus communis. The relative percentage of linoleic acid methyl ester was high (27.19%), followed by oleic acid methyl ester (21.18%) and then octane 3,5- dimethyl (16.47%), dodecane (11.39%), palmitic acid methyl ester (6.80%) and tetradecane (6.69%) as well as, some components present in lower percentage such as stearic acid methyl ester (3.32%). GC-MS analysis revealed that 16 different chemical components were identified in the Myrtus communis, with high amount of linoleic acid (27.19%) helpful in revealing the pharmaceutical value of the plant. It also provides information about its trado-medical use. GC-MS analysis is important step towards understanding the nature of active ingredients in this medicinal plant and mentioned phytocompounds would be useful in the preparation of novel drugs for treating diseases.

Evaluation of Three Phenotypic Tests vs. Duplex (coa & mecA) PCR for Detection of Methicillin-Resistance Staphylococcus aureus (MRSA) and S. epidermidis (MRSE) Strains from Patients with Nosocomial Infections (NI) in Several Mexican Hospitals

Roberto Cabrera-Contreras, Rubén Morelos-Ramírez, Enrique Meléndez-Herrada — Tue, 02 Jul 2019 00:00:00 +0000

Background: Staphylococcus aureus (SA) and Staphylococcus epidermidis are a leading cause of hospital acquired infections worldwide. Epidemiological features have also changed in Mexican hospitals and either methicillin-resistance Staphylococcus aureus (MRSA) or Staphylococcus epidermidis (SERM) infections appear to be an emerging phenomenon.

Aims: The first aim of the present study was to detect the amplification of both pairs, coa and mecA genes by duplex PCR in MRSA from Mexican patients with NI and the comparison of these results versus three routinely phenotypic MRSA-detection methods.The second aim of this study was to apply duplex PCR to exclusively detect the same pair of genes for MRSA or MRSE strains from patients with NI in several national hospitals.

Place and Duration of Study: Department of Public Health, Faculty of Medicine, National Autonomous University of Mexico (UNAM) in collaboration with six General Hospitals belonging to the Health Care & Social Services Institute for Workers (ISSSTE), the first one HGC (Hospital Gonzálo Castañeda Escobar), during a year span of August of 2004 to December of 2005, the second study was performed through an extension of a collaborative study of the five hospitals (CMN20N; FQG; LALM; GIZ & 1°Oct), during a year period of May of 2012 through November of 2013 and the seventh hospital from the third collaboration study through the National Institute of Perinatology (INPer), during a time period of August of 2012 through December of 2013.

Methodology: Among SA from HGC (n=100) strains isolated from patients with NI, 40% were MRSA. All SA strains were tested by various methods: cefoxitin (Cfx) disk-diffusion assay (DD), automated MicroScan System (MS), Oxacillin (Ox) (range 0.5 - 4.0 µg/ml) minimum inhibitory concentration (MIC), PBP2a latex agglutination test (LA) (Oxoid) and the molecular amplification by PCR of the coa and mecA genes. SA strains were previously identified by MS, and both the tube coagulase (TCT) and mannitol (MT) tests. From the second and third collaborative study, a total of 345 staphylococci strains were isolated from ISSSTE´s hospitals and INPer´s hospitals,129 SA strains from ISSSTE and 246 SE strains from INPer. These clinical (SA or SE) strains were first phenotypical characterized in both health institutions and immediately after were molecularly characterized by Duplex PCR detection of species-specific and antibiotic-resistance genes, in the Public Health Laboratory at UNAM.

Results: Out of 100 SA strains from HGC, 35 were confirmed as MRSA isolates by detection of mecA gene by PCR in addition to only 5 strains verified phenotypically but coa gen negative. These 35 MRSA strains and 53 mecA gen negative isolates, as well as 5 strains phenotypically characterized (MSSA) from NI, were assayed with all 3 laboratory tests. Only 2 clinical strains were negative to both genes: coa & mecA, but positive to all phenotypic tests. Using mecA as a gold standard (GS), category agreement for the 3 tests was: A method with higher sensitivity (SN) and specificity (SP) (SN/SP) was Cfx-DD (100/88) than other 2 methods Ox-MS (90/73) and LA (63/90). Using coa gene as a GS, category agreement for MS, and both TCT & MT were: 93/100, 95/98, and 91/98, respectively. From the second and third collaborative study, out of 129 SA strains from ISSSTE and INPer, 93% were detected by PCR as coa+, therefore 93% (120/129) of these strains were confirmed as SA. Out of 120 SA strains, 88% (106/120) were confirmed as mecA+ by PCR detection, therefore these strains are MRSA. Out of 41 SA strains from INPer, 90% (37/41) were confirmed as SA and from these strains only 43% (16/37) were confirmed positive for mecA+ therefore these strains are MRSA. As a result of third collaboration study (INPer), out of 226 SE strains, only 90% (203/226) were confirmed by PCR as coa- and 85% (172/202) of these strains were detected by PCR as mecA+, therefore these strains are MRSE.

Conclusions: Molecular detection by PCR-duplex of specie specific coa genes and antibiotic resistance mecA genes by duplex PCR in MRSA and MRSE strains, is a very useful and powerful method to rapid and precisely discriminate typical MRSA and MRSE strains in the laboratory. A Cfx-DD test performed much better for detection of MRSA strains than those using OX-MS and LA. Both assays, Cfx-DD and PCR-duplex, represent a simple, rapid, reliable approaches for the detection of methicillin resistant staphylococci and could be applied to all national hospitals, to implement fast and adequate anti-MRSA and anti-MRSE therapy. Higher percentages of MRSA strains (88% vs. 43%) were isolated from ISSSTE´s hospitals than in INPer´s hospitals, could be due to the age of patients studied, mainly neonates from INPer than older patients from ISSSTE´s hospitals.

Bacillus spp with an Antibacterial Activity

Ilham Zahir, Abdellah Houari, Mohammed Iraqui, Saad Ibnsouda — Tue, 02 Jul 2019 00:00:00 +0000

Bacterial resistance to antibiotics poses a serious challenge to chemotherapy. Indeed, in recent decades, the risk of contracting infectious diseases has increased significantly due to the emergence and spread of multi-drug-resistant bacteria. The whole world is thus confronted with this situation which motivated scientists to find out new active molecules with an antibacterial effect. Therefore, the present investigation aims to isolate and identify microorganisms secreting substances with an antibacterial activity and to partially characterize their extracts. Thus, six bacteria were isolated from soil and water of different biotopes of Fez Morocco having an antibacterial effect against M. smegmatis, M. aurum, Gram-positive and Gram-negative bacteria. Based on biochemical characterization and 16S rDNA sequence analysis, it was revealed that the isolates belong to the genus Bacillus. The antibacterial activity of three of them was fully affected by proteases (pepsin and proteinase K) and heat treatment at 80ºC and 100ºC but it was stable at 4ºC for a month and 37ºC during 3h. The lost of the activity suggests a proteinaceous nature of the bio-active compounds, which might be useful in the development of antibacterial agents after their total purification in further work against bacterial infections.

Assessment of Changes in Beta-carotene Content and Sensory Attributes of Two Sweet Potato Varieties as Influenced by Organic and Inorganic Fertilizers and Storage Methods

M. E. Essilfie, H. K. Dapaah, J. Ofosu-Anim, E. T. Blay, J. C. Norman — Tue, 02 Jul 2019 00:00:00 +0000

Two field experiments were conducted at two seasons at the research fields of the University of Education, Winneba-Mampong campus from September, 2011 to January, 2012 and April to July, 2012 to assess changes in beta-carotene content and sensory attributes of two sweet potato varieties (Okumkom and Apomuden) grown under organic and inorganic fertilizers and three different storage methods in Ghana. Cooked samples of the harvested sweet potato roots were evaluated for their sensory attributes. In the storability studies, the harvested roots were sorted, cured and stored under three storage methods for 3 months. The beta- carotene changes in the stored roots were assessed. There was a significant difference (p<0.05) between Apomuden and Okumkom grown under amendment and the control in beta-carotene content at harvest and in pit store in both seasons. The beta- carotene content of Apomuden increased by 15-30% in pit store during the minor season than at harvest. Both varieties grown under amendment and the control and stored in pit was the most effective storage method in terms of beta-carotene over ash and grass storage in both seasons. There was a significant difference (p<0.05) between Okumkom and Apomuden in root texture and palatability at harvest and after cooking during the minor season. Apomuden differed significantly (p<0.05) from Okumkom in root colour and flavour at harvest and after cooking during the major season. The application of 30-45-45 kg/ha NPK to both varieties was more acceptable with regard to root taste, colour and palatability than the other treatments during the minor season. For high beta-carotene content of sweet potato, farmers should grow Apomuden in both seasons than Okumkom. Farmers should store sweet potato roots in pit than in ash or grass after harvest for high beta-carotene content in both growing seasons. Farmers are to grow sweet potato on amended plots, especially on15-30-30 kg/ha NPK +5t/ha CM and 10t/ha CM plots during the minor season and on 30-45-45 kg/ha NPK plot during the major season for high beta-carotene content. Farmers should grow sweet potato, especially Okumkom on 30-45-45 kg/ha NPK plot for fibrous texture, palatable and overall acceptable roots during the minor season. Farmers should grow Apomuden during the major season for high root colour, flavour and overall acceptable roots. This suggests the need to modify the nutrient supply according to environmental conditions. Knowledge of these changes can facilitate the estimation of growth period, modification of nutrient supply in relation to environmental conditions, storage condition and time for different sweet potato varieties in order to meet different food industry needs.