Digestive-vacuole genesis and endocytic processes in the early intraerythrocytic stages of Plasmodium falciparum

The digestive vacuole of the malaria parasite Plasmodium falciparum is the site of haemoglobin digestion and haem detoxification, and is the target of chloroquine and other antimalarials. The mechanisms for genesis of the digestive vacuole and transfer of haemoglobin from the host cytoplasm are still debated. Here, we use live-cell imaging and photobleaching to monitor the uptake of the pH-sensitive fluorescent tracer SNARF-1-dextran from the erythrocyte cytoplasm in ring-stage and trophozoite-stage parasites. We compare these results with electron tomography of serial sections of parasites at different stages of growth. We show that uptake of erythrocyte cytoplasm is initiated in mid-ring-stage parasites. The host cytoplasm is internalised via cytostome-derived invaginations and concentrated into several acidified peripheral structures. Haemoglobin digestion and haemozoin formation take place in these vesicles. The ring-stage parasites can adopt a deeply invaginated cup shape but do not take up haemoglobin via macropinocytosis. As the parasite matures, the haemozoin-containing compartments coalesce to form a single acidic digestive vacuole that is fed by haemoglobin-containing vesicles. There is also evidence for haemoglobin degradation in compartments outside the digestive vacuole. The work has implications for the stage specificity of quinoline and endoperoxide antimalarials.

A Review of Quercus infectoria (Olivier) Galls as a Resource for Anti-parasitic Agents: In Vitro and In Vivo Studies

Parasitic diseases represent one of the causes for significant global economic, environmental and public health impacts. The efficacy of currently available anti-parasitic drugs has been threatened by the emergence of single drug- or multidrug-resistant parasite populations, vector threats and high cost of drug development. Therefore, the discovery of more potent anti-parasitic drugs coming from medicinal plants such as Quercus infectoria is seen as a major approach to tackle the problem. A systematic review was conducted to assess the efficacy of Q. infectoria in treating parasitic diseases both in vitro and in vivo due to the lack of such reviews on the anti-parasitic activities of this plant. This review consisted of intensive searches from three databases including PubMed, Science Direct and Scopus. Articles were selected throughout the years, limited to English language and fully documented. A total of 454 potential articles were identified, but only four articles were accepted to be evaluated based on inclusion and exclusion criteria. Although there were insufficient pieces of evidence to account for the efficacy of Q. infectoria against the parasites, this plant appears to have anti-leishmanial, anti-blastocystis and anti-amoebic activities. More studies in vitro and in vivo are warranted to further validate the anti-parasitic efficacy of Q. infectoria.

The role of monocytes in malaria infection

Malaria remains one of the most common human infections worldwide. In endemic areas, malaria is a leading cause of morbidity and mortality and it imposes significant socioeconomic burdens on the people affected. Monocytes are part of the immune system controlling parasite burden and protecting the host against malaria infection. Monocytes play their protective roles against malaria via phagocytosis, cytokine production and antigen presentation. Though monocytes are crucial for clearance of malaria infection, they have also been shown to cause adverse clinical outcomes. In this review, we discuss recent findings regarding the role of monocytes in malaria via mechanisms such as parasite detection and clearance, pro-inflammatory activities, and activation of other immune components. We also highlight the role of different monocyte subsets, and other myeloid cells that are involved in malaria infection. However, more investigations are required in order to explore the exact roles of these monocytes in malaria infection.

A descriptive study on the knowledge and attitude of nurses toward the prevention of pressure ulcers in the intensive care unit

INTRODUCTION

The study's objectives are to investigate the level of knowledge, attitude, and performance (KAP) of nurses on the prevention of pressure ulcers (PUs) prevention in the intensive care (ICU) and also to identify the relationship between nurses' KAP toward the implementation of preventive measures for PUs.

MATERIALS AND METHODS

This cross-sectional study was conducted among 60 registered nurses in the ICU at Taiping Hospital. to assess the nurses' knowledge and attitude level using the Knowledge and Attitude on prevention of PUs questionnaire. A descriptive analysis and Pearson Correlation were used to analyze the data.

RESULT

From a total of 60 nurses 36 (60%) of nurses demonstrated a moderate level of KAP, and 17 (28%) demonstrated a high level of knowledge. They also exhibited neutral attitudes towards PUs prevention 49 (82%). The findings revealed a positive relationship between nurses' KAP toward implementing preventive measures on PUs (p=0.04; r=0.3). The findings show that nurses regularly performed the assessment of the risk factors of PUs for all hospitalized patients when performing PUs care. However, the plan for preventive nursing care was not properly reviewed.

CONCLUSION

This study suggested that appropriate guidelines, education programs, and an environment that makes it possible to provide continuing education should be created for nurses to prevent PUs in the ICU.

Factors contributing to poor compliance with anti-TB treatment among tuberculosis patients

Tuberculosis (TB) has made a comeback. It has become a resurgent public health problem in developing countries in the tropics and is the leading cause of death from any single infectious agent. Non-compliance to anti-tuberculosis treatment is the most serious problem in TB control. A cross-sectional study was conducted to investigate the determinants of poor compliance with anti-tuberculosis treatment among tuberculosis patients in Kota Bharu, Kelantan, Malaysia in 1999. A total of 390 patients were included in the study of which 130 were tuberculosis patients who defaulted treatment and 260 were those compliant to treatment. Data collection was done by interviewing the patients and collecting clinical and laboratory data from their medical records. Using multiple logistic regression analysis, patients who were not on direct observed therapy (DOT) lived distant to the health facility, were non-intravenous drug users (IVDU) and were HIV positive had statistically significant higher odds of being non-compliant. Patients should be given treatment under direct supervision with special attention to IVDU and HIV positive groups. Anti-TB treatment should be accessible to patients at the nearest health center from their residence. Interventions with health education programs emphasizing the benefits of treatment compliance should be implemented by further large-scale multicentered studies.

Development of an inhibitive enzyme assay for copper

In this work the development of an inhibitive assay for copper using the molybdenum-reducing enzyme assay is presented. The enzyme is assayed using 12-molybdophosphoric acid at pH 5.0 as an electron acceptor substrate and NADH as the electron donor substrate. The enzyme converts the yellowish solution into a deep blue solution. The assay is based on the ability of copper to inhibit the molybdenum-reducing enzyme from the molybdate-reducing Serratia sp. Strain DRY5. Other heavy metals tested did not inhibit the enzyme at 10 mg l(-1). The best model with high regression coefficient to measure copper inhibition is one-phase binding. The calculated IC50 (concentration causing 50% inhibition) is 0.099 mg l(-1) and the regression coefficient is 0.98. The comparative LC50, EC50 and IC50 data for copper in different toxicity tests show that the IC50 value for copper in this study is lower than those for immobilized urease, bromelain, Rainbow trout, R. meliloti, Baker's Yeast dehydrogenase activity Spirillum volutans, P. fluorescens, Aeromonas hydrophilia and synthetic activated sludge assays. However the IC50 value is higher than those for Ulva pertusa and papain assays, but within the reported range for Daphnia magna and Microtox assays.

Measuring pH of the Plasmodium falciparum digestive vacuole by flow cytometry

Studies show that the pH of the malaria parasite's digestive vacuole (DV) plays a key role in the physiological functions of this organelle and antimalarial drug accumulation, and yet is technically difficult to measure. In this study, a flow cytometry-based technique was developed to measure the DV pH using a ratiometric pH indicator, FITC-dextran loaded into the DV of saponin-permeabilized parasites. To calculate the DV pH, a standard pH calibration curve was generated by incubating the saponin-permeabilized cells in buffers with different pH in the presence of an ionophore, CCCP. The measured average pH of the DV was 5.27 ± 0.03 that is approximately the same in the parasites observed microscopically by Hayward et al. (2006) (5.50 ± 0.14) using the same probe. The removal of glucose from the medium, causing a rapid depletion of parasite ATP, resulted in an alkalization of the DV. The DV was reacidified upon restoration of glucose to the medium. This technique provides a rapid, simple and quantitative measurement of the DV pH on a large number of cells. It will also be useful in future attempts to evaluate the effect of antimalarial drugs (i.e. chloroquine and artemisinin-based drugs) in pH changes of the DV.

Synthesis, Antimalarial Activity and Molecular Dynamics Studies of Pipecolisporin: A Novel Cyclic Hexapeptide with Potent Therapeutic Potential

Malaria, caused by Plasmodium species and transmitted by Anopheles mosquitoes, continues to pose a significant global health threat. Pipecolisporin, a cyclic hexapeptide isolated from Nigrospora oryzae, has emerged as a promising antimalarial candidate due to its potent biological activity and stability. This study explores the synthesis, antimalarial activity, and computational studies of pipecolisporin, aiming to better understand its therapeutic potential. The peptide was successfully synthesized using Fmoc-based solid-phase peptide synthesis (SPPS) followed by cyclization in solution. The purified compound was characterized using HPLC and mass spectrometry, confirming a molecular ion peak at m/z [M + H]+ 692.4131, which matched the calculated mass. Structural verification through 1H- and 13C-NMR demonstrated strong alignment with the natural product. Pipecolisporin exhibited significant antimalarial activity with an IC50 of 26.0 ± 8.49 nM, highlighting its efficacy. In addition to the experimental synthesis, computational studies were conducted to analyze the interaction of pipecolisporin with key malaria-related enzymes, such as dihydrofolate reductase, plasmepsin V, and lactate dehydrogenase. These combined experimental and computational insights into pipecolisporin emphasize the importance of hydrophobic interactions, particularly in membrane penetration and receptor binding, for its antimalarial efficacy. Pipecolisporin represents a promising lead for future antimalarial drug development, with its efficacy, stability, and binding characteristics laying a solid foundation for ongoing research.

A review on lab-on-chip as a potential diagnostic tool for early detection of Plasmodium knowlesi

Massive elimination efforts have been done to control the malaria disease caused by the emergence of the fifth human malaria parasite known as Plasmodium knowlesi. Early detection of the parasite is important in treating malaria infection. Microscopic examination of Giemsa-stained thick and thin blood films is the gold standard for laboratory malaria diagnosis, while rapid diagnostic tests (RDTs), polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) are significant diagnostic techniques to detect acute infection. However, these methods have several limitations in which it could delay the treatment. The potential of lab-on-chip (LOC) as a point-of-care diagnostic tool for malaria fulfils the requirement of limitations where it is able to produce early detection of malaria infection. This review discusses advantages and disadvantages of malaria diagnostic methods as well as new approaches that could be used for high speed, sensitive and reliable malaria detection to prevent the disease from causing severe complications and even fatal if left untreated.