Studies on Zygote Morphogenesis in rodent Malaria parasite, Plasmodium berghei

Summary Development of polarity is well studied in cell systems such as mammalian neurons, epithelial cells and Caenorhabditis elegans zygotes. In Plasmodium the spherical and presumed apolar female gamete morphs during the 24 hours after fertilisation in the mosquito midgut into a polarised ookinete, however, little is known about how Plasmodium zygotes develop polarity. It is known that endocytosis-mediated protein transport is generally necessary for the establishment and maintenance of polarity in epithelial cells and neurons, and Rab11A GTPase is an important regulator of protein transport via recycling endosomes. Rab11A has been predicted to be involved in cytokinesis in Plasmodium falciparum and is essential in Plasmodium berghei. Here I show the expression profile of P. berghei Rab11A (PbRab11A) across the life cycle and use a promoter swap strategy to investigate the role of PbRab11A in ookinete development. By expressing PbRab11A under the clag promoter or ama-1 promoter, its expression in sexual stages is greatly reduced while its essential expression in asexual blood stages is maintained. Whilst gamete production and fertility rates remained unaffected, the ookinete conversion rates of CLAG and AMA-1 promoter swap mutants are reduced by up to 99% and 98% respectively and transmission through the mosquito is prevented. TEM analysis and immunofluorescence microscopy of developmental and structural markers show that Rab11A-CLAG promoter swap mutant zygotes lay down the Inner Membrane Complex (IMC) and are apically oriented but appear stop morphological progression and remain spherical. Western blot and transcriptome analysis of Rab11A - CLAG promoter swap mutant suggest marginal expression delay as well as deregulation of some of the transcripts of ookinete development and structural markers, and the majority of deregulated transcripts are independent of previously shown translationally stored transcripts. We predict that Rab11A is not involved in the establishment of P. berghei zygote polarity, mitosis, activation of stored mRNAs nor extensive reactivation of post-meiotic transcription but conceivably in the delivery of plasma membrane to the growing apical outgrowth which is expected to be a coordinated process of Rab11A mediated membrane trafficking and cytoskeletal dynamics. As a second line of enquiry, the establishment of polarity in P. berghei zygote with respect to the point of male and female gamete fusion is ongoing. Establishment of polarity in embryos and zygotes is dependent on the development of the axis of polarity and fertilization signals mediated by the male gamete in C. elegans and some plants. Establishment of the axis of polarity and therefore the emergence of apical complex with respect to the point of gamete fusion has not been previously studied in Plasmodium. To visualise the process of fertilization, membrane localized green fluorescence protein (GFP) expressing P. berghei male gamete producer parasites were generated. Female specific protein phosphatase with kelch-like domain (PPKL), IMC sub-compartment protein 1 (ISP1) and Glideosome-associated protein 50 (GAP50) are known to be associated with the apical complex, and are essential for P. berghei zygote to ookinete transition. Further, female specific MTOC (Microtubule Organising Center) markers - spindle pole body protein (SPBP) is also predicted to be associated with apical complex development during zygote to ookinete transition. Therefore, to investigate the emergence of the apical bud with respect to the point of gamete fusion during fertilization and through the zygote to ookinete transition, female gamete specific membrane localized mCherry expressing or PPKL/ ISP1/ GAP50/ SPBP labelled with mCherry expressing P. berghei parasite cell lines were generated in male gamete specific GFP producing P. berghei parasites. Initial fluorescent microscopy confirms the stage specific red-green fluorescence in respective transgenic P. berghei parasite lines. Further studies to confirm the hypothesis that the point of male gamete fusion cues for the point of emergence of apical bud in the zygote are ongoing

Evaluation of wound healing activity of topical phenytoin in an excision wound model in rats

Background: Wound healing is a significant healthcare problem in today’s medical practice. Despite extensive treatment modalities that are supposed to hasten the wound healing process, the outcomes of existing methods are far from optimal. One such agent that has been tried previously and found controversial in wound healing is phenytoin. Therefore, this study was planned to evaluate and compare wound healing effect of topical phenytoin with povidone iodine ointment in rats.Methods: This study was conducted after approval from Institutional Animal Ethics Committee (IAEC). Wound healing activity of topical phenytoin (1 g% and 2 g%) was assessed in excision wound model in Sprague Dawley rats (n=8), which was compared with topical petroleum jelly and povidone iodine ointment. Parameters studied included wound area on day 0, 4, 8, 12, 16, 20, percentage wound contraction, percentage wound healing from day 0 to day 20 and period of re-epithelisation.Results: Wound surface area decreased in all treatment groups from day 0 through day 20 and the percentage wound closure was better in both the preparations (1% and 2%) of phenytoin when compared wih control and povidone iodine, but this was not statistically significant. Furthermore, the days required for complete re-epithelisation were less with phenytoin treated groups. There was no statistical difference between both the preparations of phenytoin.Conclusion: In this study, it was found that topical phenytoin accelerates wound healing process in an excision wound model

Wearable Technology and Extended Applications

We are living in the turbulent flow of technology, which increases exponentially with every second we live. Technology has made our life ease, effective and enables us to do something we always dreamed of. Wearable Technology is the next step that is taken towards the next generation interaction with new modules and future designed gadgets that works with much efficiency, flexibility, accuracy and can perform various complex operation with ease. Wearable technologies are adding more layers to our life by increasing the ways we communicate and share information with each other. The continuity of these devices creates a continuous link between people that they can relate to each other. Wearable Technology is aimed to provide the real time interaction with new evolving mobile widgets and gadgets. We would see how this technology will overcome the limitations of the existing mobile gadgets and bring it to the new extended level in compare to current scenario. Wearable Technology is new technological revolution that would create a world faster reliable and secure data transmission network. We would analysis the capability, expandability and limitations of it

Newer drugs in the management of diabetes mellitus

Modern life style with present days technological advances have made human life sedentary. This is causing increasing prevalence of obesity and physical inactivity amongst population. The number of cases of diabetes worldwide in the year 2000 among adults 20 years of age is estimated to be 171 million in recent reports   and is said to rise to more than 300 million by 2025. The raised plasma glucose levels give rise to complications in the form of microvascular and macrovascular complications diminished quality of life with reduced life expectancy. The currently available drugs used in the management of type II DM are not completely satisfactory in regard of controlling blood glucose level, many of the times they are associated with undesirable side effects. Hence there is continuous ongoing work in development of newer drugs, which are safe, efficacious and potent as well as free of undesirable effects such as sustained hypoglycaemia. Fortunately there are newer drug, few of them approved while other still knocking the door from the classes of drug such as GLP-1Mimetic, DPP-4 Inhibitors and others. Here we have tried to cover them in brief

Formulation and Characterization of the Improved Solubility, In Vivo Bioavailability and Antioxidant Activity of Apigenin-Phospholipid Complex (APLC)

In the present study a phospholipid based complex of apigenin (APLC) was prepared with a goal of improving its aqueous solubility, dissolution, in vivobioavailability, and antioxidant activity

Study of effects of donepezil and aspirin on working memory in rats using electroconvulsive shock model

Background: Memory is the most common cognitive ability lost with dementia commonly seen in Alzheimer’s disease (AD). Donepezil was the first cholinesterase inhibitor to be licensed in UK for AD. There is preliminary evidence that aspirin decreases the risk and delays the onset of AD. Low dose aspirin users had numerically lower prevalence of Alzheimer’s dementia and had better cognitive function than non-users.Methods: Retention of conditioned avoidance response (CAR) was assessed by using repeated electroconvulsive shocks (ECS) in rats. Rats were divided into five groups: control (pretreated with distilled water), ECS (150 V, 50 Hz, with intensity of 210 mA for 0.5 sec) pretreated, combined aspirin (6.75 mg/kg) and pretreated ECS, combined donepezil (0.32 mg/kg) and pretreated ECS, combined aspirin, donepezil and pretreated ECS groups. Data were analyzed using the Chi-square test and ANOVA.Results: Findings show that administration of ECS daily for 8 days results in transient amnesia and disruption of retention of CAR. Aspirin and donepezil administration significantly increased the retention of CAR in comparison to ECS. However, aspirin failed to show an increase in the retention of CAR as compared to donepezil. The combination of the two drugs showed statistically significant increase in the retention of CAR than either of these drugs given alone.Conclusion: Neuroinflammation plays an important role in the pathophysiology of neurodegenerative disorder like AD. Combination of aspirin with donepezil increased the nootropic and neuroprotective effect of aspirin and thus may hold great clinical significance in such disorders

A prospective study, to determine adverse effects of anti-retroviral agents in rural tertiary care teaching hospital

Background: Acquired immunodeficiency syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV). Objective of this study was to evaluate the adverse drug reaction profile of anti-retroviral drugs in HIV patients in terms of causality, severity and preventability.Methods: Patients newly started on ART were followed prospectively for a period of initial six months and were interviewed in person during their routine follow-up or visit following development of any ADRs. ADRs were screened clinically and investigated accordingly for causality, severity and preventability.Results: Out of 59 cases, zidovudine+lamivudine+nevirapine (ZLN) was the most commonly used ART regimen. A total 122 ADRs involving various systems were observed in these patients; majority being related to gastrointestinal system (54.10%). Most of these ADRs were observed in the ZLN regimen followed by the stavudine+lamivudine+nevirapine (SLN) regimen. On causality assessment in ZLN regimen, 74.58% of ADRs were possible, while 25.42% were probable. Severity assessment showed that most of the ADR were mild whereas on preventability assessment it was observed that most of the ADRs were not-preventable.Conclusions: Antiretroviral drugs are not solely responsible for the ADRs due to these medications; various co-morbid and predisposing conditions share the responsibility. An efficient pharmacovigilance is imperative by means of improving ADR reporting and monitoring, in order to improve compliance and acceptability of ART

Zygote morphogenesis but not the establishment of cell polarity in plasmodium berghei Is controlled by the small GTPase, RAB11A

Plasmodium species are apicomplexan parasites whose zoites are polarized cells with a marked apical organisation where the organelles associated with host cell invasion and colonization reside. Plasmodium gametes mate in the mosquito midgut to form the spherical and presumed apolar zygote that morphs during the following 24 hours into a polarized, elongated and motile zoite form, the ookinete. Endocytosis-mediated protein transport is generally necessary for the establishment and maintenance of polarity in epithelial cells and neurons, and the small GTPase RAB11A is an important regulator of protein transport via recycling endosomes. PbRAB11A is essential in blood stage asexual of Plasmodium. Therefore, a promoter swap strategy was employed to down-regulate PbRAB11A expression in gametocytes and zygotes of the rodent malaria parasite, Plasmodium berghei which demonstrated the essential role of RAB11A in ookinete development. The approach revealed that lack of PbRAB11A had no effect on gamete production and fertility rates however, the zygote to ookinete transition was almost totally inhibited and transmission through the mosquito was prevented. Lack of PbRAB11A did not prevent meiosis and mitosis, nor the establishment of polarity as indicated by the correct formation and positioning of the Inner Membrane Complex (IMC) and apical complex. However, morphological maturation was prevented and parasites remained spherical and immotile and furthermore, they were impaired in the secretion and distribution of microneme cargo. The data are consistent with the previously proposed model of RAB11A endosome mediated delivery of plasma membrane in Toxoplasma gondii if not its role in IMC formation and implicate it in microneme function