Witches' Broom Disease of Lime Contributes to Phytoplasma Epidemics and Attracts Insect Vectors.

An insect-transmitted phytoplasma causing Witches' Broom Disease of Lime (WBDL) is responsible for the drastic decline in lime production in several countries. However, it is unclear how WBDL phytoplasma (WBDLp) induces witches' broom symptoms and if these symptoms contribute to the spread of phytoplasma. Here we show that the gene encoding SAP11 of WBDLp (SAP11WBDL) is present in all WBDLp isolates collected from diseased trees. SAP11WBDL interacts with acid lime (Citrus aurantifolia) TCP transcription factors, specifically members of the TB1/CYC class that have a role in suppressing axillary branching in plants. Sampling of WBDLp-infected lime trees revealed that WBDLp titers and SAP11WBDL expression levels were higher in symptomatic leaves compared with asymptomatic sections of the same trees. Moreover, the witches' brooms were found to attract the vector leafhopper. Defense genes that have a role in plant defense responses to bacteria and insects are more downregulated in witches' brooms compared with asymptomatic sections of trees. These findings suggest that witches' broom-affected parts of the trees contribute to WBDL epidemics by supporting higher phytoplasma titers and attracting insect vectors.

Identification of patients with preeclampsia from normal subjects using wavelet-based spectral analysis of heart rate variability.

BACKGROUND: The spectral analysis of the heart rate variability (HRV) shows a decrease in the power of the high frequency (HF) component in preeclamptic pregnancy compared with normal pregnancy; such a decrease is associated with an increase in the low frequency (LF) and the very low frequency (VLF) power. The physiological interpretation is that preeclamptic pregnancy is associated with a facilitation of sympathetic regulation and an attenuation of parasympathetic influence of HR compared with non-pregnancy and normal pregnancy. OBJECTIVE: To use an efficient nased on spectral analysis non-invasive technique to identify preeclamptic pregnant subjects from normal pregnant in Oman. METHODS: The soft-decision wavelet-based technique is implemented to find the power of the HRV bands in high resolution manner compared to the classical fast Fourier Transform method. Data was obtained from 20 preeclamptic pregnant subjects and 20 normal pregnant controls of the same pregnancy duration, obtained from Nizwa and Sultan Qaboos University hospitals in Oman. RESULTS: The soft-decision wavelet method succeeds to identify patients from normal pregnant with specificity, sensitivity and accuracy of 90%, 80% and 85%, respectively, compared to the FFT which results in 75% specificity, sensitivity and accuracy. CONCLUSION: The LF power obtained by Soft-decision wavelet decomposition is shown to be a successful feature for identification of preeclampsia.

Investigation of heart rate variability of patients undergoing coronary artery bypass grafting (CABG).

BACKGROUND: Myocardial revascularization by coronary artery bypass grafting (CABG) is an effective measure for reducing symptoms and mortality in patients with unstable or severe coronary artery disease (CAD). Autonomic function can be estimated non-invasively using heart rate variability (HRV). HRV of patients undergoing CABG is investigated before and after CABG using a soft-decision wavelet based spectral analysis. OBJECTIVE: The main purpose of this work is to evaluate non-invasively HRV in patients undergoing CABG before operation; and to monitor the status of patients through HRV investigation on day 6 and day 30 after the CABG operation. The study intends to contribute scientific value to understanding the effect of CABG on the cardiovascular autonomic function and surgical outcome. METHODS: The soft-decision wavelet-based technique is used in this work in order to measure the power spectral density of the three main bands (VLF, LF, and HF) of HRV in 24 patients undergoing CABG operation, before the operation (Group 1: G1), and 6 days after operation (Group 2: G2) and 30 days after operation (Group 3: G3). The data is obtained from Sultan Qaboos University hospital in Oman. RESULTS: The HF power increases in 22 out of 24 patients in G2 compared to G1. While the LF power decreases in 21 out of 24 patients in G2 compared to G1. Comparing G3 to G1 the LF power decreases in 20 patients. The sum of the VLF and LF power is reduced in G2 in all 24 subjects compared to G1, and in 19 subjects in G3 compared to G1. CONCLUSIONS: The power spectral density of the HF shows increase in patients recorded on day 6 after operation compared to patients before the operation. The LF shows a decrease in G2 compared to G1. The results of G3 after 30 days of operation still show an increase of the HF power and a decrease in the LF power in most of the patients compared to their values before operation.

Assessment of aerobic fitness and its correlates in Omani adolescents using the 20-metre shuttle run test: A pilot study.

OBJECTIVE: To assess aerobic fitness in male and female adolescents using the multistage 20-metre shuttle run test and correlate it with selected fitness variables. METHOD: The subjects comprised 83 girls and 64 boys aged 15-16 years, randomly selected from two segregated government schools in Muscat. After the pupils filled in a short questionnaire on their personal leisure time activities of the preceding week, their heights and weights were measured. Aerobic fitness was assessed by estimating each pupil's minimal oxygen uptake levels (VO2max) using the multistage 20-metre shuttle running test (20-MST). RESULTS: Boys spent more time than girls on leisure physical activities, television, computer and video games and the Internet. The estimated VO2max in both boys and girls showed high correlation with their weekly physical activities. The time spent on television and computer negatively correlated with VO2max in girls but not in boys. Girls had higher body mass index (BMI) and less VO2max compared to boys; BMI showed a negative correlation with VO2max in girls but not in boys. CONCLUSION: Aerobic fitness in this sample was higher in boys than in girls and was strongly influenced by weekly physical activities in both genders. The 20-MST has proved a simple and inexpensive field test for aerobic fitness that could be implemented on a wide scale.