The novel Plasmodium berghei protein S14 is essential for sporozoite gliding motility and infectivity.

Plasmodium sporozoites are the infective forms of the malaria parasite in the mosquito and vertebrate host. Gliding motility allows sporozoites to migrate and invade mosquito salivary glands and mammalian hosts. Motility and invasion are powered by an actin-myosin motor complex linked to the glideosome, which contains glideosome-associated proteins (GAPs), MyoA and the myosin A tail-interacting protein (MTIP). However, the role of several proteins involved in gliding motility remains unknown. We identified that the S14 gene is upregulated in sporozoite from transcriptome data of Plasmodium yoelii and further confirmed its transcription in P. berghei sporozoites using real-time PCR. C-terminal 3×HA-mCherry tagging revealed that S14 is expressed and localized on the inner membrane complex of the sporozoites. We disrupted S14 in P. berghei and demonstrated that it is essential for sporozoite gliding motility, and salivary gland and hepatocyte invasion. The gliding and invasion-deficient S14 knockout sporozoites showed normal expression and organization of inner membrane complex and surface proteins. Taken together, our data show that S14 plays a role in the function of the glideosome and is essential for malaria transmission.

Secreted protein with altered thrombospondin repeat (SPATR) is essential for asexual blood stages but not required for hepatocyte invasion by the malaria parasite Plasmodium berghei.

Upon entering its mammalian host, the malaria parasite productively invades two distinct cell types, that is, hepatocytes and erythrocytes during which several adhesins/invasins are thought to be involved. Many surface-located proteins containing thrombospondin Type I repeat (TSR) which help establish host-parasite molecular crosstalk have been shown to be essential for mammalian infection. Previous reports indicated that antibodies produced against Plasmodium falciparum secreted protein with altered thrombospondin repeat (SPATR) block hepatocyte invasion by sporozoites but no genetic evidence of its contribution to invasion has been reported. After failing to generate Spatr knockout in Plasmodium berghei blood stages, a conditional mutagenesis system was employed. Here, we show that SPATR plays an essential role during parasite's blood stages. Mutant salivary gland sporozoites exhibit normal motility, hepatocyte invasion, liver stage development and rupture of the parasitophorous vacuole membrane resulting in merosome formation. But these mutant hepatic merozoites failed to establish a blood stage infection in vivo. We provide direct evidence that SPATR is not required for hepatocyte invasion but plays an essential role during the blood stages of P. berghei.

A comparison between ProSeal laryngeal mask airway and Air-Q Blocker in patients undergoing elective laparoscopic cholecystectomy.

BACKGROUND AND AIMS: ProSeal laryngeal mask airway (PLMA) is an established device for airway management, while Air-Q Blocker (AQB) is a relatively new supraglottic device. The aim of this study is to compare AQB against PLMA in adults undergoing laparoscopic cholecystectomy under general anesthesia. MATERIAL AND METHODS: Eighty-eight adult patients scheduled for laparoscopic cholecystectomy under general anesthesia were randomly allocated into two groups. A drain tube (gastric tube for PLMA and blocker tube for AQB) was inserted through the drain channel of the respective device. PLMA was inserted in Group P (n = 44) and AQB was inserted in Group A (n = 44) to secure the airway. The primary endpoint was airway seal pressure. Secondarily, we sought to compare overall insertion success, ease of insertion, hemodynamic effects after initial placement, ease of drain tube placement, and perioperative oropharyngolaryngeal morbidity between the devices. RESULTS: Oropharyngeal seal pressures for AQB and PLMA were 31.5 ± 2.41 and 29.41 ± 2.14 cm H2O, respectively (P = 0.01). Insertion time was longer with AQB than PLMA, 25.59 ± 5.71 and 18.66 ± 3.15 seconds, respectively (P = 0.001). Ease and success rate of insertion was better with PLMA compared to AQB. Failure of device insertion was seen in 2 cases of Group A. Gastric distension was seen in 4 patients in Group A, requiring replacement with endotracheal tube in two patients. Ventilation was successful in all 44 patients with PLMA. Both the devices were comparable in providing a patent airway and adequate oxygenation during controlled ventilation. There was an increased trend of airway trauma and complications in the AQB group. CONCLUSION: Both PLMA and AQB show similar efficacy in maintaining ventilation and oxygenation, during laparoscopic surgery. However, proper positioning and functioning of the blocker tube of AQB is a limiting factor, and needs further evaluation.

PKAc is not required for the preerythrocytic stages of Plasmodium berghei.

Plasmodium sporozoites invade hepatocytes to initiate infection in the mammalian host. In the infected hepatocytes, sporozoites undergo rapid expansion and differentiation, resulting in the formation and release of thousands of invasive merozoites into the bloodstream. Both sporozoites and merozoites invade their host cells by activation of a signaling cascade followed by discharge of micronemal content. cAMP-dependent protein kinase catalytic subunit (PKAc)-mediated signaling plays an important role in merozoite invasion of erythrocytes, but its role during other stages of the parasite remains unknown. Becaused of the essentiality of PKAc in blood stages, we generated conditional mutants of PKAc by disrupting the gene in Plasmodium berghei sporozoites. The mutant salivary gland sporozoites were able to glide, invaded hepatocytes, and matured into hepatic merozoites which were released successfully from merosome, however failed to initiate blood stage infection when inoculated into mice. Our results demonstrate that malaria parasite complete preerythrocytic stages development without PKAc, raising the possibility that the PKAc independent signaling operates in preerythrocytic stages of P. berghei.

Effect of Different Dosages of Intravenous Midazolam Premedication on Patients Undergoing Head and Neck Surgeries- A Double Blinded Randomized Controlled Study.

INTRODUCTION: Benzodiazepines primarily acts on the central nervous system. Most patients are extremely anxious in the pre-operative period. Excessive anxiety adversely influences anaesthetic induction and often leads to functional impairment and poor recovery after surgery. AIM: To determine whether amnesia, anxiety, sedation and cardio respiratory symptoms are affected while administering two different doses of intravenous midazolam (0.02 mg/kg & 0.06 mg/kg). MATERIALS AND METHODS: Two forty patients posted for head and neck surgeries were involved in this double blinded prospective randomised controlled trial. The patients were randomized into two main groups, Group 1 receiving 0.02 mg/kg and Group 2 receiving 0.06 mg/kg midazolam intravenously as premedication. Visual recognition and recall were tested using eight laminated A4 size posters pre-operatively and four further images were shown at the postoperative interview. Anxiety was evaluated by a Visual Analogue Scale (VAS) and sedation depth was determined by the Observer's Assessment of Alertness/Sedation Scale (OAAS) scale. Vital signs including heart rate, respiratory rate, mean blood pressure and arterial oxygen saturation (SpO2) were monitored. Statistical analysis was done using paired Student's t-test and Chi-square test. RESULTS: VAS scores were lower in Group 2 (0.06 mg/kg) than in Group 1 (0.02 mg/kg) at T15 (15 minutes after the injection of midazolam). Comparison of OAAS scores among Group 1 and Group 2 showed that more patients in Group 1 were alert at T15 compared to Group 2. Recall of events was significantly lower in Group 2 compared to Group 1. There was no significant statistical variation in haemodynamic parameters between the groups except for decreased diastolic blood pressure and room air saturation in Group 2. CONCLUSION: A higher dosage of midazolam improves the quality of anxiolysis and sedation with lesser rates of intraoperative recall and maintains haemodynamic stability.

A Novel and Conserved Plasmodium Sporozoite Membrane Protein SPELD is Required for Maturation of Exo-erythrocytic Forms.

Plasmodium sporozoites are the infective forms of malaria parasite to vertebrate host and undergo dramatic changes in their transcriptional repertoire during maturation in mosquito salivary glands. We report here the role of a novel and conserved Plasmodium berghei protein encoded by PBANKA_091090 in maturation of Exo-erythrocytic Forms (EEFs) and designate it as Sporozoite surface Protein Essential for Liver stage Development (PbSPELD). PBANKA_091090 was previously annotated as PB402615.00.0 and its transcript was recovered at maximal frequency in the Serial Analysis of the Gene Expression (SAGE) of Plasmodium berghei salivary gland sporozoites. An orthologue of this transcript was independently identified in Plasmodium vivax sporozoite microarrays and was designated as Sporozoite Conserved Orthologous Transcript-2 (scot-2). Functional characterization through reverse genetics revealed that PbSPELD is essential for Plasmodium liver stage maturation. mCherry transgenic of PbSPELD localized the protein to plasma membrane of sporozoites and early EEFs. Global microarray analysis of pbspeld ko revealed EEF attenuation being associated with down regulation of genes central to general transcription, cell cycle, proteosome and cadherin signaling. pbspeld mutant EEFs induced pre-erythrocytic immunity with 50% protective efficacy. Our studies have implications for attenuating the human Plasmodium liver stages by targeting SPELD locus.