In vitro culture of coffee zygotic embryos for germplasm preservation

Immature zygotic embryos of Coffea arabica L. Cv. Cauvery (Catimor) were cultured on Murashige and Skoog (1962) (MS) medium supplemented with abscisic acid (ABA) at 0, 0.4, 3.8, 18.9, 37.8 and 75.6 μM., L-cystein hydrochloride at 50 mg 1^-1 and sucrose at 3%. Cultures were preserved in parafilm sealed Petri dishes in dark at a temperature of 25 ± 1 °C for up to two years. The preserved embryos were taken out from the media at 6 month intervals in order to test their viability by germination on MS + NAA (0.5 μM) + BA (4.4 μM). On the preservation media devoid of ABA or with a low concentration (0.4 μM) of ABA, the embryos germinated and showed higher mortality with increasing duration of storage. In contrast, the embryos became increasingly dormant with increasing concentrations of ABA and a 74.2% survival was found even after 2 years on medium supplemented with 18.9 μM or 37.8 μM of ABA. The results suggest that embryos can be preserved with a little loss of viability in the presence of ABA even at the normal room temperature (25 + 1 °C) up to two years without any transfer. Application of this technique for germplasm preservation of coffee is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Immunoelectron Microscopy for Locating Calvin Cycle Enzymes in the Thylakoids of Synechocystis 6803

Unicellular cyanobacteria Synechocystis 6803 were fixed using high-pressure freezing （HPF） and freeze substitution without any chemical cross-linkers. Immunoelectron microscopy of these cells showed that five sequential enzymes of the Calvin cycle （phosphoriboisomerase, phosphoribulokinase, ribulose-1,5-bisphosphate carboxylase/oxygenase （RuBisCO）, 3-phosphoglyceratekinase and glyceraldehyde-3-phosphate dehydrogenase） and the catalytic portion of the chloroplast H^＋-ATP synthase （CF1） are located adjacent to the thylakoid membranes. Cell-free extracts of Synechocystis were processed by ultracentrifugation to isolate thylakoid fractions sedimenting at 40 000, 90 000, and 150 000 g. Among these, the 150 000-g fraction showed the highest linked activity of the above five sequential Calvin cycle enzymes and also the highest coordinated activity of light and dark reactions as assessed by ribose-5-phosphate （R-5-P） ＋ADP dependent CO2 fixation. Immunogold labeling of this membrane fraction confirmed the presence of the above five enzymes as well as the catalytic portion of the CF1 ATP synthase. Notably, the protein A-gold labeling of the thylakoids was observed without use of chemical cross-linkers and in spite of the normal washing steps used during standard immunolabeling. The results showed that soluble Calvin cycle enzymes might be organized along the thylakoid membranes.     

Factors Controlling Vegetation Fires in Protected and Non-Protected Areas of Myanmar

Fire is an important disturbance agent in Myanmar impacting several ecosystems. In this study, we quantify the factors impacting vegetation fires in protected and non-protected areas of Myanmar. Satellite datasets in conjunction with biophysical and anthropogenic factors were used in a spatial framework to map the causative factors of fires. Specifically, we used the frequency ratio method to assess the contribution of each causative factor to overall fire susceptibility at a 1km scale. Results suggested the mean fire density in non-protected areas was two times higher than the protected areas. Fire-land cover partition analysis suggested dominant fire occurrences in the savannas (protected areas) and woody savannas (non-protected areas). The five major fire causative factors in protected areas in descending order include population density, land cover, tree cover percent, travel time from nearest city and temperature. In contrast, the causative factors in non-protected areas were population density, tree cover percent, travel time from nearest city, temperature and elevation. The fire susceptibility analysis showed distinct spatial patterns with central Myanmar as a hot spot of vegetation fires. Results from propensity score matching suggested that forests within protected areas have 11% less fires than non-protected areas. Overall, our results identify important causative factors of fire useful to address broad scale fire risk concerns at a landscape scale in Myanmar.     

Micro-Economic Impact of Congenital Heart Surgery: Results of a Prospective Study from a Limited-Resource Setting

Introduction

The microeconomic impact of surgery for congenital heart disease is unexplored, particularly in resource limited environments. We sought to understand the direct and indirect costs related to congenital heart surgery and its impact on Indian households from a family perspective.

Methods

Baseline and first follow-up data of 644 consecutive children admitted for surgery for congenital heart disease (March 2013 – July 2014) in a tertiary referral hospital in Central Kerala, South India was collected prospectivelyfrom parents through questionnaires using a semi-structured interview schedule.

Results

The median age was 8.2 months (IQR: 3.0– 36.0 months). Most families belonged to upper middle (43.0%) and lower middle (35.7%) socioeconomic class. Only 3.9% of families had some form of health insurance. The median expense for the admission and surgery was INR 201898 (IQR: 163287–266139) [I$ 11989 (IQR: 9696–15804)], which was 0.93 (IQR: 0.52–1.49) times the annual family income of affected patients. Median loss of man-days was 35 (IQR: 24–50) and job-days was 15 (IQR: 11–24). Surgical risk category and hospital stay duration significantly predicted higher costs. One in two families reported overwhelming to high financial stress during admission period for surgery. Approximately half of the families borrowed money during the follow up period after surgery.

Conclusion

Surgery for congenital heart disease results in significant financial burden for majority of families studied. Efforts should be directed at further reductions in treatment costs without compromising the quality of care together with generating financial support for affected families.     

Laribacter hongkongensis: an emerging pathogen of infectious diarrhea

Laribacter hongkongensis is relatively a new name in the list of bacterial pathogens for gastroenteritis and travelers’ diarrhea. Addition of another name increases burden on the enteric infections as a whole. L. hongkongensis belongs to Neisseriaceae family of β subclass Proteobacteria. L. hongkongensis was initially isolated in Hong Kong from blood and empyema of an alcoholic cirrhotic patient in 2001, followed by reports from Korea and China, representing a total of 38 articles in PubMed until April 2013. As of now, there is no report from Indian subcontinent where infectious diarrhea is very much prevalent and a major burden. This review provides information about the microbiological characteristics, consideration of an emerging pathogen, relative pathogenicity, genome and proteome content, resistance toward multiple antibiotics, adaptability to different stress, and other features since its time of discovery. Investigation for this bacterium may avoid misidentification as other microbial flora. Further studies like the geographical distribution, type of infection, disease burden, pathogenicity, or genomic exploration of this bacterium will be useful in characterizing them properly. This bacterium may possibly be the emerging threat to public health.     

Mycobacterium tuberculosis MtrB Sensor Kinase Interactions with FtsI and Wag31 Proteins Reveal a Role for MtrB Distinct from That Regulating MtrA Activities

The septal association of Mycobacterium tuberculosis MtrB, the kinase partner of the MtrAB two-component signal transduction system, is necessary for the optimal expression of the MtrA regulon targets, including ripA, fbpB, and ftsI, which are involved in cell division and cell wall synthesis. Here, we show that MtrB, irrespective of its phosphorylation status, interacts with Wag31, whereas only phosphorylation-competent MtrB interacts with FtsI. We provide evidence that FtsI depletion compromises the MtrB septal assembly and MtrA regulon expression; likewise, the absence of MtrB compromises FtsI localization and, possibly, FtsI activity. We conclude from these results that FtsI and MtrB are codependent for their activities and that FtsI functions as a positive modulator of MtrB activation and MtrA regulon expression. In contrast to FtsI, Wag31 depletion does not affect MtrB septal assembly and MtrA regulon expression, whereas the loss of MtrB increased Wag31 localization and the levels of PknA/PknB (PknA/B) serine-threonine protein kinase-mediated Wag31 phosphorylation. Interestingly, we found that FtsI decreased levels of phosphorylated Wag31 (Wag31∼P) and that MtrB interacted with PknA/B. Overall, our results indicate that MtrB interactions with FtsI, Wag31, and PknA/B are required for its optimal localization, MtrA regulon expression, and phosphorylation of Wag31. Our results emphasize a new role for MtrB in cell division and cell wall synthesis distinct from that regulating the MtrA phosphorylation activities.