Plant growth promotion and suppression of bacterial leaf blight in rice by Paenibacillus polymyxa Sx3.

The effects and mechanisms of Paenibacillus polymyxa Sx3 on growth promotion and the suppression of bacterial leaf blight in rice were evaluated in this study. The results from a plate assay indicated that Sx3 inhibited the growth of 20 strains of Xanthomonas oryzae pv. oryzae (Xoo). Rice seedling experiments indicated that Sx3 promoted plant growth and suppressed bacterial leaf blight. In addition, bacteriological tests showed that Sx3 was able to fix nitrogen, solubilize phosphate and produce indole acetic acid, indicating that various mechanisms may be involved in the growth promotion by Sx3. The culture filtrate of P. polymyxa Sx3 reduced bacterial growth, biofilm formation and disrupted the cell morphology of Xoo strain GZ 0005, as indicated by the transmission and scanning electron microscopic observations. In addition, MALDI-TOF MS analysis revealed that Sx3 could biosynthesize two types of secondary metabolites fusaricidins and polymyxin P. In summary, this study clearly indicated that P. polymyxa Sx3 has strong in vitro and in vivo antagonistic activity against Xoo, which may be at least partially attributed to its production of secondary metabolites. SIGNIFICANCE AND IMPACT OF THE STUDY: Antagonistic bacteria can grow well in their originating environment. However, it is unclear whether antagonistic bacteria were able to survive in different ecological environments. This study revealed that Paenibacillus polymyxa Sx3 isolated from rhizosphere soil of cotton significantly promoted the plant growth and suppressed bacterial leaf blight in rice. Therefore, it could be inferred that P. polymyxa Sx3 has the potential to be used as biocontrol agents in plants grown in different ecological environments.

Halotolerant bacteria belonging to operational group Bacillus amyloliquefaciens in biocontrol of the rice brown stripe pathogen Acidovorax oryzae.

AIMS: The aim of this study was to evaluate the antagonistic activity of halotolerant bacteria against rice brown stripe pathogen Acidovorax oryzae. METHODS AND RESULTS: Fifteen of 136 isolates of halotolerant bacteria exhibited strong in vitro and in vivo antagonistic activity against both strains of A. oryzae. The 15 antagonistic isolates were identified as 'operational group Bacillus amyloliquefaciens' based on physiological and biochemical features, fatty acid profiles as well as sequence analysis of 16S rRNA, gyrA and rpoB genes. Furthermore, this result indicated that the most effective antagonistic isolates K5-3 and PPB6 could produce siderophore in iron-limiting medium, and four kinds of secondary metabolites based on MALDI-TOF analysis. In addition, the culture filtrates of isolates K5-3 and PPB6 caused the damage of cell membrane evidenced by the TEM images, and resulted in 73-80% reduction in cell numbers, 55-65% reduction in biofilm formation, and 42-50% reduction in swimming ability of both strains of A. oryzae. CONCLUSIONS: These isolates in particular K5-3 and PPB6 of halotolerant bacteria markedly inhibited the growth of A. oryzae. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report on biological control of halotolerant bacteria against bacterial brown stripe of rice.

Echocardiographic Assessment of Cardiac Changes During Normal Pregnancy Among Nigerians.

BACKGROUND: Pregnancy is a physiological process associated with an increased hemodynamic load and cardiac structural remodeling. Limited echocardiographic information exists on cardiac chambers, left ventricular (LV) systolic and diastolic functions, and LV mass during trimesters of normal pregnancy among African women. MATERIALS AND METHODS: Echocardiography was done at the beginning of the second trimester, beginning of the third trimester, and middle of the third trimester for 100 normal pregnant women and at one visit for age-matched 100 nonpregnant women. The data were analyzed using the Statistical Package for Social Sciences (SPSS) version 17 software. Analysis of variance was used to compare within trimesters, and a P value of <0.05 was considered significant. RESULTS: The mean (SD) ages of the patients and controls were 28.20 (±5.91) and 28.35 (±6.06) years, respectively (age range = 19-44 years, P = 0.86). Cardiac chambers, LV systolic function, and LV mass and its index increased significantly during pregnancy. A significant increase in A-wave velocity but slight increase in E-wave velocity and a reduction in tissue e' velocity at the septal margin but a progressive increase in a' velocity were also observed (P < 0.05). CONCLUSION: Cardiac chamber dimensions, LV wall thickness, and mass, most indices of LV systolic and diastolic function, though within normal range, were significantly higher in pregnant than in nonpregnant Nigerian women.

Cardiovascular responses to treadmill exercise in Nigerian hypertensives with left ventricular hypertrophy.

BACKGROUND: Left ventricular hypertrophy (LVH) is an independent risk factor for adverse cardiac outcomes in hypertensive patients. OBJECTIVE: This study is designed to assess the cardiovascular responses to treadmill exercise among Nigerian hypertensives with echocardiographically proven LVH. MATERIALS AND METHODS: Fifty hypertensive patients with LVH (27 males and 23 females) between 30 and 65 years of age were studied in Nigeria. 50 hypertensive patients without LVH and 50 normal subjects who were age and sex matched served as controls. All patients and control subjects underwent M-mode, 2-D and Doppler ECHO-studies and the Bruce protocol treadmill exercise test. RESULTS: The study showed that the estimated maximal oxygen consumption (MVO2) in MET reduced progressively from 8.39 ± 1.26 (normotensive control) to 7.62 ± 1.33 (hypertensive without LVH), 6.27 ± 0.99 (hypertensive with LVH) (P<0.0001ANOVA). The duration of exercise (s) was also reduced in that order from 455.4 ± 79.1 to 411.6 ±8 2.3, 315.8 ± 75.6 respectively (P<0.0001). The systolic blood pressure (SBP) and pressure rate product (PRP) during maximal exercise were also increased in hypertensives with LVH and hypertensive without LVH when compared to normotensive controls. The hypertensives with LVH and hypertensives without LVH also showed significant limitation to heart rate increase with exercise compared to normotensive controls (P<0.003). CONCLUSION: This study demonstrated significant impairment of exercise capacity in hypertensives with or without LVH compared to normotensive subjects. Both earlier recognition and improved understanding of LVH may lead to more effective therapeutic strategies for this cardiovascular risk factor.

Ambulatory blood pressure profile and left ventricular geometry in Nigerian hypertensives.

BACKGROUND: Left ventricular hypertrophy (LVH) is an independent cardiac risk factor in hypertensives and the structural classification of left ventricular (LV) geometry provides additional prognostic information. Ambulatory blood pressure (ABP) monitoring has been shown to be superior to office blood pressure (BP) in relation to hypertension LVH. We investigated ambulatory BP variables in relation to LV geometric patterns in Nigerian hypertensives. MATERIALS AND METHODS: A total of 130 patients (males = 96, females = 34) with hypertension had their 24-hours ambulatory BP and trans-thoracic 2D/M- mode echocardiography. Data were analyzed with SPSS 13.0. P < 0.05 was considered statistically significant. RESULTS: The mean age of the patients was 54.08±11.88 years. The prevalence rate of abnormal LV geometry was 48.4%. Mean ambulatory Systolic BP (day time, night time and 24-hour-average) was significantly higher in patients with LVH compared with those without LVH. Day-night systolic and diastolic BP decay (i.e. percentage nocturnal decline in BP) was also significantly lower in LVH group than in the group without LVH. Patients with eccentric LVH had abnormal day time mean ambulatory systolic BP, night time mean ambulatory systolic BP, elevated day time and night time systolic BP loads, as well as non-dipping diastolic BP pattern. Significant correlates of LV mass index in this study population were mean ambulatory systolic BP (day time: r = 0.355, P = 0.004; night time: r = 0.343, P = 0.005; 24- hour average: r = 0.358, P = 0.004) and day-night decay (systolic: r = -0.388, P = 0.007; diastolic: r = -0.290, P = 0.022) as well as 24-hour systolic BP variability. CONCLUSION: The presence of LVH in hypertension was associated with higher mean ambulatory systolic BP and lower percentage nocturnal decline in systolic and diastolic BP than its absence which appeared to be worse in patients with eccentric LV geometry when compared with other geometric patterns.

The significance of mild renal dysfunction in chronic heart failure.

BACKGROUND: Heart failure is a major public health concern. Prediction models in heart failure have employed echo-cardiography and other advanced laboratory parameters in predicting the risk of mortality. However, most of the patients in the resource poor economies still do not have easy access to these advanced technology. OBJECTIVE: To determine the clinical and echocardiographic correlates of patients with chronic heart failure (CHF) in the presence or mild renal disease (MRD). METHODS: One hundred CHF patients were categorized based on their estimated glomerular filtration rates into either normal renal function or MRD. The clinical and echocardiographic variables of both groups were compared. RESULTS: There were 38 females and 62 males with an overall mean age of 54 years. A significantly greater proportion of patients with mild renal disease presented in New York Heart Association classes 3 and 4 (82.9% vs 27.1%). Patients with MRD had echocardiographic findings of a significantly larger left atrial dimension, lower ejection fraction and fractional shortening and shorter deceleration time. A significantly greater proportion of patients with mild renal disease also had moderate-severe mitral and tricuspid regurgitation and grades 2-3 diastolic dysfunction compared to patients without mild renal disease. Patients with MRD also exhibited a significantly greater degree of deterioration in the fractional shortening and ejection fraction compared to non-MRD patients. Multivariate regression analysis indicated that a low ejection fraction and a low fractional shortening were significantly associated with MRD. CONCLUSION: Identification of MRD in chronic heart failure patients using the estimated glomerular filtration rate is valuable in resource poor countries. The presence of MRD in CHF is associated with poor left ventricular function and increased deterioration of ventricular function.

Blood pressure response to an exercise treadmill test, and echocardiographic left ventricular geometry in Nigerian normotensive diabetics.

OBJECTIVES: This study evaluated normotensive diabetic patients' blood pressure response to graded exercise and their echocardiographic pattern of left ventricular geometry. METHODS: A descriptive, cross-sectional, hospital-based study was carried out on 30 normotensive type 2 diabetic patients and 34 controls, aged 30 to 60 years. The outcome measures were to determine the exercise-related variable, blood pressure response, and left ventricular geometry by means of echocardiography. RESULTS: Nineteen (29.7%) and 11 (17.2%) normotensive diabetic subjects had normal left ventricular geometry and concentric left ventricular remodelling, respectively. None of the subjects had concentric or eccentric left ventricular hypertrophy. On this basis, the normotensive diabetic subjects were divided to two groups: G1 (normal) and G2 (concentric left ventricular remodelling). The groups had comparable mean age, body mass index (BMI), fasting blood glucose (FBG) and two-hour post-prandial blood glucose values, and heart rate, systolic (SBP) and diastolic blood pressure (DBP) at rest. G2 patients had higher mean duration of diabetes than G1 subjects (69.0 +/- 9.48 vs 18.7 +/- 8.7 months; p = 0.007). Peak systolic blood pressure was significantly higher in G2 than G1 subjects (213.6 +/- 20.1 vs 200.0 +/- 15.3 mmHg; p = 0.04). Although there was no statistically significant difference in the left ventricular (LV) mass index between the groups, G2 patients had significantly higher relative wall thicknesses than G1 patients (0.53 +/- 0.03 vs 0.41 +/- 0.04; p < 0.001). CONCLUSION: Normotensive diabetic subjects with concentric left ventricular remodelling have increased blood pressure reactivity to exercise. It is probable, as suggested in earlier studies, that increased blood pressure reactivity to exercise is an indicator of target-organ damage, particularly in normotensive diabetics.

Burden of obesity in essential hypertension: pattern and prevalence.

UNLABELLED: Obesity continues to be an epidemic worldwide. There also continues to be a relationship between obesity and hypertension both causal and consequentially. The study aims at determining the prevalence and pattern of overweight and obesity among our patients being managed for essential hypertension. MATERIAL AND METHODS: The study was a cross sectional study. Consecutive patients diagnosed with essential hypertension were recruited from two university teaching hospitals in the South West of Nigeria. Demographic data such as age, gender, weight and height were obtained from patients at recruitment. Patients with congestive heart failure, secondary hypertension, chronic kidney disease, and other chronic diseases were excluded. Pregnant women were also excluded. Obesity was defined according to WHO classification. Statistical analysis was done by the Statistical Package for Social Sciences version 11.0. RESULTS: One thousand one hundred and two (1102) consecutive hypertensive patients were recruited. Two hundred and eighty six (286) were dropped due to evidence of overt heart failure (98) and chronic kidney disease and others (188). There were (420) males (51.5%) and 396 females (48.5%), mean age 54.97 (±13.14) years. (Range 10-91). 7.6% (62) were underweight (36 males, 26 Females): 260 (31.9%) were overweight, consisting of 148 males and 112 females: 135 (16.5%) had mild obesity consisting of 48 males and 87 females: 43(5.3%) had moderate obesity with 15 males and 28 females while 30(3.7%) had severe obesity (consisting of 22 females). CONCLUSION: About two thirds of the hypertensive patients seen in two teaching hospitals in the South West of Nigeria in this study were either overweight or obese. Therefore lifestyle modification geared toward weight reduction should be emphasized in these patients.

Burden of obesity in essential hypertension: pattern and prevalence

Obesity continues to be an epidemic worldwide. There also continues to be a relationship between obesity and hypertension both causal and consequentially. The study aims at determining the prevalence and pattern of overweight and obesity among our patients being managed for essential hypertension.The study was a cross sectional study. Consecutive patients diagnosed with essential hypertension were recruited from two university teaching hospitals in the SouthWest of Nigeria. Demographic data such as age, gender, weight and height were obtained from patients at recruitment. Patients with congestive heart failure, secondary hypertension, chronic kidney disease, and other chronic diseases were excluded. Pregnant women were also excluded. Obesity was defined according toWHOclassification.Statistical analysis was done by the Statistical Package for Social Sciences version 11.0.One thousand one hundred and two (1102) consecutive hypertensive patients were recruited. Two hundred and eighty six (286) were dropped due to evidence of overt heart failure (98) and chronic kidney disease and others (188).There were (420) males (51.5%) and 396 females (48.5%), mean age 54.97 (±13.14) years. (Range 10-91).7.6% (62) were underweight (36 males, 26 Females): 260 (31.9%) were overweight, consisting of 148 males and 112 females: 135 (16.5%) had mild obesity consisting of 48 males and 87 females: 43(5.3%) had moderate obesity with 15 males and 28 females while 30 (3.7%) had severe obesity (consisting of 22 females).About two thirds of the hypertensive patients seen in two teaching hospitals in the SouthWest of Nigeria in this study were either overweight or obese. Therefore lifestyle modification geared toward weight reduction should be emphasized in these patients