Production Kinetics and Tensioactive Characteristics of Biosurfactant from a Pseudomonas aeruginosa Mutant Grown on Waste Frying Oils

Various waste frying oils (WFOs) were evaluated as substrates for rhamnolipid production by Pseudomonas aeruginosa mutant EBN-8 in the presence or absence of rhamnolipid precursor, under single-/batch-fed conditions. Soybean WFO was the best substrate, producing 9.3 g rhamnolipid l⁻¹ with the specific product yield of 2.7 g g⁻¹ h, under batch-fed cultivation with the addition of rhamnolipid precursor. The surface tension of the cell-free culture broth (CFCB) was 29.1 mN m⁻¹ and the interfacial tension against n-hexadecane was <1 mN m⁻¹. The hydrocarbon/ CFCB systems showed the relative emulsion stability to be in the range of 89.7–92.3.     

A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation

We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which works especially well with poor mask fit.Can not intubate, can not ventilate" (CICV) is a potentially life threatening situation. In this video we present a simulation of the technique we used in a case of CICV where oxygenation and ventilation were maintained by inserting an endotracheal tube (ETT) nasally down to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.A 13 year old patient was taken to the operating room for incision and drainage of a neck abcess and direct laryngobronchoscopy. After preoxygenation, anesthesia was induced intravenously. Mask ventilation was found to be extremely difficult because of the swelling of the soft tissue. The face mask could not fit properly on the face due to significant facial swelling as well. A direct laryngoscopy was attempted with no visualization of the larynx. Oxygen saturation was difficult to maintain, with saturations falling to 80%. In order to oxygenate and ventilate the patient, an endotracheal tube was then inserted nasally after nasal spray with nasal decongestant and lubricant. The tube was pushed gently and blindly into the hypopharynx. The mouth and nose of the patient were sealed by hand and positive pressure ventilation was possible with 100% O₂ with good oxygen saturation during that period of time. Once the patient was stable and well sedated, a rigid bronchoscope was introduced by the otolaryngologist showing extensive subglottic and epiglottic edema, and a mass effect from the abscess, contributing to the airway compromise. The airway was secured with an ETT tube by the otolaryngologist.This video will show a simulation of the technique on a patient undergoing general anesthesia for dental restorations.Download video file.^{(28M, mov)}     

Guidelines for Elective Pediatric Fiberoptic Intubation

Fiberoptic intubation in pediatric patients is often required especially in difficult airways of syndromic patients i.e. Pierre Robin Syndrome. Small babies will desaturate very quickly if ventilation is interrupted mainly to high metabolic rate. We describe guidelines to perform a safe fiberoptic intubation while maintaining spontaneous breathing throughout the procedure. Steps requiring the use of propofol pump, fentanyl, glycopyrrolate, red rubber catheter, metal insuflation hook, afrin, lubricant and lidocaine spray are shown.Download video file.^{(69M, mov)}     

Role of alphaPhe-291 residue in the phosphate-binding subdomain of catalytic sites of Escherichia coli ATP synthase

The role of αPhe-291 residue in phosphate binding by Escherichia coli F₁F₀-ATP synthase was examined. X-ray structures of bovine mitochondrial enzyme suggest that this residue resides in close proximity to the conserved βR246 residue. Herein, we show that mutations αF291D and αF291E in E. coli reduce the ATPase activity of F₁F₀ membranes by 350-fold. Yet, significant oxidative phosphorylation activity is retained. In contrast to wild-type, ATPase activities of mutants were not inhibited by MgADP-azide, MgADP-fluoroaluminate, or MgADP-fluoroscandium. Whereas, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) inhibited wild-type ATPase essentially completely, ATPase in mutants was inhibited maximally by ∼75%, although reaction still occurred at residue βTyr-297, proximal to αPhe-291 in the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts in βE (empty) catalytic sites, as shown previously by X-ray structure analysis. Phosphate protected against NBD-Cl inhibition in wild-type but not in mutants. In addition, our data suggest that the interaction of αPhe-291 with phosphate during ATP hydrolysis or synthesis may be distinct.     

Genetic diversity of Salmonella enterica serovar Paratyphi A from different geographical regions in Asia

AIMS: Subtyping of Salmonella Paratyphi A isolates from India, Pakistan, Indonesia and Malaysia was carried out by pulsed-field gel electrophoresis (PFGE) to assess the extent of genetic diversity of these isolates from different endemic countries. METHODS AND RESULTS: A total of 39 human isolates of Salmonella Paratyphi A from Pakistan, India, Indonesia and Malaysia were studied using PFGE analysis following digestion of chromosomal DNA with XbaI. Seven isolates from Pakistan were resistant to ampicillin, tetracycline and cotrimoxazole. It was noted that Salmonella Paratyphi A isolates obtained from outbreaks in India had limited genetic diversity and probably belonged to closely related clones. Significant genetic homogeneity was observed among antimicrobial-resistant isolates from Pakistan and antimicrobial-sensitive isolates from Pakistan and Indonesia, respectively. CONCLUSIONS: PFGE was a useful subtyping technique to differentiate Salmonella Paratyphi A from different endemic countries. However, it fails to differentiate the antimicrobial-resistant and -sensitive strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of the present study verify the usefulness of PFGE in characterizing and comparing strains of Salmonella Paratyphi A. Our study suggests that a limited number of clones are responsible for paratyphoid fever in these countries.     

Influence of Plant Growth Promoting Rhizobacterial Inoculation on Wheat Productivity Under Soil Salinity Stress

Soil salinity affects the growth and yield of crops. The stress of soil salinity on plants can be mitigated by inoculation of plant growth promoting bacteria (PGPR). The influence of PGPR inoculation on wheat (Triticum aestivum L.) crop productivity under salinity stress has not been properly addressed so far. Therefore, the present study was conducted to investigate the effects of various PGPR strains (W14, W10 and 6K; alone and combined) at several growth attributes of wheat plant under different soil salinity gradients (3, 6 and 9 dS m-1). The growth attributes of wheat (height, roots, shoots, spikes, grains quality, biological and economical yield, nutrients nitrogen, phosphorus and potassium in grains) were highly affected by salinity and decreased with increasing salinity level. The PGPR inoculation substantially promoted growth attributes of wheat and prominent results were observed in W14 × W10 × 6K treatment at all salinity levels. The results suggest that inoculation of PGPR is a potential strategy to mitigate salinity stress for improving wheat growth and yield.