Human natural killer cells control Plasmodium falciparum infection by eliminating infected red blood cells.

Immunodeficient mouse-human chimeras provide a powerful approach to study host-specific pathogens, such as Plasmodium falciparum that causes human malaria. Supplementation of immunodeficient mice with human RBCs supports infection by human Plasmodium parasites, but these mice lack the human immune system. By combining human RBC supplementation and humanized mice that are optimized for human immune cell reconstitution, we have developed RBC-supplemented, immune cell-optimized humanized (RICH) mice that support multiple cycles of P. falciparum infection. Depletion of human natural killer (NK) cells, but not macrophages, in RICH mice results in a significant increase in parasitemia. Further studies in vitro show that NK cells preferentially interact with infected RBCs (iRBCs), resulting in the activation of NK cells and the elimination of iRBCs in a contact-dependent manner. We show that the adhesion molecule lymphocyte-associated antigen 1 is required for NK cell interaction with and elimination of iRBCs. Development of RICH mice and validation of P. falciparum infection should facilitate the dissection of human immune responses to malaria parasite infection and the evaluation of therapeutics and vaccines.

In vivo splenic clearance correlates with in vitro deformability of red blood cells from Plasmodium yoelii-infected mice.

Recent experimental and clinical studies suggest a crucial role of mechanical splenic filtration in the host's defense against malaria parasites. Subtle changes in red blood cell (RBC) deformability, caused by infection or drug treatment, could influence the pathophysiological outcome. However, in vitro deformability measurements have not been directly linked in vivo with the splenic clearance of RBCs. In this study, mice infected with malaria-inducing Plasmodium yoelii revealed that chloroquine treatment could lead to significant alterations to RBC deformability and increase clearance of both infected and uninfected RBCs in vivo. These results have clear implications for the mechanism of human malarial anemia, a severe pathological condition affecting malaria patients.

Hydroponics: current trends in sustainable crop production.

The combination of Hydroponics with smart technology in farming is novel and has promise as a method for effective and environmentally friendly crop production. This technology eliminates the need for soil and reduces water usage by providing nutrients straight to the plant's roots. The Internet of Things (IoT), sensors, and automation are all used in "smart farming," which allows for constant monitoring of soil conditions, nutrient levels, and plant vitality to facilitate fine-grained management and optimization. The technology-driven strategy improves crop output, quickens growth rates, and keeps conditions ideal all year round regardless of weather or other environmental circumstances. In addition, smart farming lessens the need for organic chemical inputs, promotes environmentally safe methods of pest management, and minimizes the amount of waste produced. This ground-breaking strategy may significantly alter the agricultural sector by encouraging regionalized food production, enhancing food security, and adding to more resilient farming practices. This comprehensive review delves into current trends in Hydroponics, highlighting recent advancements in smart farming systems, such as Domotics, Data Acquisition, Remote Cultivation, and automated AI systems. The review also underscores the various types and advantages of smart farming hydroponic technology, emphasizing the requirements for achieving efficiency in this innovative domain. Additionally, it explores future goals and potential developments, paving the way for further advancements in hydroponic smart farming.

Role of Plasmodium berghei cGMP-dependent protein kinase in late liver stage development.

The liver is the first organ infected by Plasmodium sporozoites during malaria infection. In the infected hepatocytes, sporozoites undergo a complex developmental program to eventually generate hepatic merozoites that are released into the bloodstream in membrane-bound vesicles termed merosomes. Parasites blocked at an early developmental stage inside hepatocytes elicit a protective host immune response, making them attractive targets in the effort to develop a pre-erythrocytic stage vaccine. Here, we generated parasites blocked at a late developmental stage inside hepatocytes by conditionally disrupting the Plasmodium berghei cGMP-dependent protein kinase in sporozoites. Mutant sporozoites are able to invade hepatocytes and undergo intracellular development. However, they remain blocked as late liver stages that do not release merosomes into the medium. These late arrested liver stages induce protection in immunized animals. This suggests that, similar to the well studied early liver stages, late stage liver stages too can confer protection from sporozoite challenge.

Covalent Binding of Antibodies to Cellulose Paper Discs and Their Applications in Naked-eye Colorimetric Immunoassays.

This report presents two methods for the covalent immobilization of capture antibodies on cellulose filter paper grade No. 1 (medium-flow filter paper) discs and grade No. 113 (fast-flow filter paper) discs. These cellulose paper discs were grafted with amine functional groups through a silane coupling technique before the antibodies were immobilized on them. Periodate oxidation and glutaraldehyde cross-linking methods were used to graft capture antibodies on the cellulose paper discs. In order to ensure the maximum binding capacity of the capture antibodies to their targets after immobilization, the effects of various concentrations of sodium periodate, glutaraldehyde, and capture antibodies on the surface of the paper discs were investigated. The antibodies that were coated on the amine-functionalized cellulose paper discs through a glutaraldehyde cross-linking agent showed enhanced binding activity to the target when compared to the periodate oxidation method. IgG (in mouse reference serum) was used as a reference target in this study to test the application of covalently immobilized antibodies through glutaraldehyde. A new paper-based, enzyme-linked immunosorbent assay (ELISA) was successfully developed and validated for the detection of IgG. This method does not require equipment, and it can detect 100 ng/ml of IgG. The fast-flow filter paper was more sensitive than the medium-flow filter paper. The incubation period of this assay was short and required small sample volumes. This naked-eye, colorimetric immunoassay can be extended to detect other targets that are identified with conventional ELISA.

Integrated analysis of the Plasmodium species transcriptome.

The genome sequence available for different Plasmodium species is a valuable resource for understanding malaria parasite biology. However, comparative genomics on its own cannot fully explain all the species-specific differences which suggests that other genomic aspects such as regulation of gene expression play an important role in defining species-specific characteristics. Here, we developed a comprehensive approach to measure transcriptional changes of the evolutionary conserved syntenic orthologs during the intraerythrocytic developmental cycle across six Plasmodium species. We show significant transcriptional constraint at the mid-developmental stage of Plasmodium species while the earliest stages of parasite development display the greatest transcriptional variation associated with critical functional processes. Modeling of the evolutionary relationship based on changes in transcriptional profile reveal a phylogeny pattern of the Plasmodium species that strictly follows its mammalian hosts. In addition, the work shows that transcriptional conserved orthologs represent potential future targets for anti-malaria intervention as they would be expected to carry out key essential functions within the parasites. This work provides an integrated analysis of orthologous transcriptome, which aims to provide insights into the Plasmodium evolution thereby establishing a framework to explore complex pathways and drug discovery in Plasmodium species with broad host range.

De Novo Generated Human Red Blood Cells in Humanized Mice Support Plasmodium falciparum Infection.

Immunodeficient mouse-human chimeras provide a powerful approach to study host specific pathogens like Plasmodium (P.) falciparum that causes human malaria. Existing mouse models of P. falciparum infection require repeated injections of human red blood cells (RBCs). In addition, clodronate lipsomes and anti-neutrophil antibodies are injected to suppress the clearance of human RBCs by the residual immune system of the immunodeficient mice. Engraftment of NOD-scid Il2rg-/- mice with human hematopoietic stem cells leads to reconstitution of human immune cells. Although human B cell reconstitution is robust and T cell reconstitution is reasonable in the recipient mice, human RBC reconstitution is generally poor or undetectable. The poor reconstitution is mainly the result of a deficiency of appropriate human cytokines that are necessary for the development and maintenance of these cell lineages. Delivery of plasmid DNA encoding human erythropoietin and interleukin-3 into humanized mice by hydrodynamic tail-vein injection resulted in significantly enhanced reconstitution of erythrocytes. With this improved humanized mouse, here we show that P. falciparum infects de novo generated human RBCs, develops into schizonts and causes successive reinvasion. We also show that different parasite strains exhibit variation in their ability to infect these humanized mice. Parasites could be detected by nested PCR in the blood samples of humanized mice infected with P. falciparum K1 and HB3 strains for 3 cycles, whereas in other strains such as 3D7, DD2, 7G8, FCR3 and W2mef parasites could only be detected for 1 cycle. In vivo adaptation of K1 strain further improves the infection efficiency and parasites can be detected by microscopy for 3 cycles. The parasitemia ranges between 0.13 and 0.25% at the first cycle of infection, falls between 0.08 and 0.15% at the second cycle, and drops to barely detectable levels at the third cycle of infection. Compared to existing mouse models, our model generates human RBCs de novo and does not require the treatment of mice with immunomodulators.

STEVOR is a Plasmodium falciparum erythrocyte binding protein that mediates merozoite invasion and rosetting.

Variant surface antigens play an important role in Plasmodium falciparum malaria pathogenesis and in immune evasion by the parasite. Although most work to date has focused on P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1), two other multigene families encoding STEVOR and RIFIN are expressed in invasive merozoites and on the infected erythrocyte surface. However, their role during parasite infection remains to be clarified. Here we report that STEVOR functions as an erythrocyte-binding protein that recognizes Glycophorin C (GPC) on the red blood cell (RBC) surface and that its binding correlates with the level of GPC on the RBC surface. STEVOR expression on the RBC leads to PfEMP1-independent binding of infected RBCs to uninfected RBCs (rosette formation), while antibodies targeting STEVOR in the merozoite can effectively inhibit invasion. Our results suggest a PfEMP1-independent role for STEVOR in enabling infected erythrocytes at the schizont stage to form rosettes and in promoting merozoite invasion.

Variable expression of the 235 kDa rhoptry protein of Plasmodium yoelii mediate host cell adaptation and immune evasion.

The severity of infections caused by the malaria parasite Plasmodium is in part due to the rapid multiplication cycles in the blood of an infected individual. A fundamental step in this phenomenon is the invasion of selected erythrocytes of the host by the parasite. The py235 rhoptry protein multigene family of the rodent malaria parasite Plasmodium yoelii has been implicated in mediating host cell selection during erythrocyte invasion and virulence. Here we show using quantitative real-time polymerase chain reaction and Western blot analysis that variations in the amounts of py235 may be a mechanism that the parasite uses to define its host cell repertoire. High levels of py235 expression leads to a wider range of erythrocytes invaded and therefore increased virulence. In contrast, to evade PY235-specific immunity, the parasite downregulates py235 thereby decreasing the host cell repertoire and virulence. These results demonstrate a new mechanism where variations in the amounts of parasite ligand define the parasite host cell repertoire and enable it to evade host immunity.