Investigating the evolution of apoptosis in malaria parasites: the importance of ecology

Apoptosis is a precisely regulated process of cell death which occurs widely in multicellular organisms and is essential for normal development and immune defences. In recent years, interest has grown in the occurrence of apoptosis in unicellular organisms. In particular, as apoptosis has been reported in a wide range of species, including protozoan malaria parasites and trypanosomes, it may provide a novel target for intervention. However, it is important to understand when and why parasites employ an apoptosis strategy before the likely long-and short-term success of such an intervention can be evaluated. The occurrence of apoptosis in unicellular parasites provides a challenge for evolutionary theory to explain as organisms are expected to have evolved to maximise their own proliferation, not death. One possible explanation is that protozoan parasites undergo apoptosis in order to gain a group benefit from controlling their density as this prevents premature vector mortality. However, experimental manipulations to examine the ultimate causes behind apoptosis in parasites are lacking. In this review, we focus on malaria parasites to outline how an evolutionary framework can help make predictions about the ecological circumstances under which apoptosis could evolve. We then highlight the ecological considerations that should be taken into account when designing evolutionary experiments involving markers of cell death, and we call for collaboration between researchers in different fields to identify and develop appropriate markers in reference to parasite ecology and to resolve debates on terminology.Host-parasite interactio

Comparison of Singh’s index in view of osteoporosis in patient with in tertrochanteric fracture and intracapsular fracture

Background: Osteoporosis is a progressive, systemic, skeletal disease with low bone mass. Diagnosing osteoporosis in practice is a major challenge, where resources are limited and costly. Measurement of osteoporosis through Singh’s index in proximal femur fracture patients is consistent with Bone Mineral Density estimation like DEXA scan. Singh’s index is a reliable, reproducible and easily available investigation for osteoporosis. The aim of this study is to evaluate the Singh’s index of the patients with inter-trochanteric and intra-capsular fracture. Methods: A retrospective observational study of 20 IT and IC fracture each. Singh’s index evaluated from the X-rays at time of fracture presentation. Other required information collected at presentation. Results: Out of 40 Patients, 6 had Singh's Index Grade 1 (15%), 11 had Grade 2 (27.5%), 10 had Grade 3 (25%), 7 had Grade 4 (17.5%), 6 had Grade 5 (15%), 0 Patients had Singh’s index Grade 6. There was no noticeable significant variation in relation of gender with the type of fracture. Patients with higher age tend to have a lower grade of Singh’s index. Conclusions: Singh’s Index indeed represents bone quality and a fall in the grades predisposes to fractures. Inter trochanteric fractures are common in the older age group with poor Singh’s index (<3) compared to the relatively younger age group with Singh’s index around 3. Gender, exercise, history of hypertension and diabetes, sunlight exposure, etc. has no significant impact on Singh's Index. Age is deciding factor for Singh’s Index

Proteomic analysis of skin invasion by blood fluke larvae.

BackgroundDuring invasion of human skin by schistosome blood fluke larvae (cercariae), a multicellular organism breaches the epidermis, basement membrane, and dermal barriers of skin. To better understand the pathobiology of this initial event in schistosome infection, a proteome analysis of human skin was carried out following invasion by cercariae of Schistosoma mansoni.Methodology and resultsHuman skin samples were exposed to cercariae for one-half hour to two hours. Controls were exposed to water used to collect cercariae in an identical manner, and punctured to simulate cercarial tunnels. Fluid from both control and experimental samples was analyzed by LC/MS/MS using a linear ion trap in "triple play" mode. The coexistence of proteins released by cercariae and host skin proteins from epidermis and basement membrane confirmed that cercarial tunnels in skin were sampled. Among the abundant proteins secreted by cercariae was the cercarial protease that has been implicated in degradation of host proteins, secreted proteins proposed to mediate immune invasion by larvae, and proteins implicated in protection of parasites against oxidative stress. Components of the schistosome surface tegument, previously identified with immune serum, were also released. Both lysis and apoptosis of epidermal cells took place during cercarial invasion of the epidermis. Components of lysed epidermal cells, including desmosome proteins which link cells in the stratum granulosum and stratum spinosum, were identified. While macrophage-derived proteins were present, no mast cell or lymphocyte cytokines were identified. There were, however, abundant immunoglobulins, complement factors, and serine protease inhibitors in skin. Control skin samples incubated with water for the same period as experimental samples ensured that invasion-related proteins and host protein fragments were not due to nonspecific degeneration of the skin samples.ConclusionsThis analysis identified secreted proteins from invasive larvae that are released during invasion of human skin. Analysis of specific host proteins in skin invaded by cercariae served to highlight both the histolytic events facilitating cercarial invasion, and the host defenses that attempt to arrest or retard invasion. Proteins abundant in psoriatic skin or UV and heat-stressed skin were not abundant in skin invaded by cercariae, suggesting that results did not reflect general stress in the surgically removed skin specimen. Abundant immunoglobulins, complement factors, and serine protease inhibitors in skin form a biochemical barrier that complements the structural barrier of the epidermis, basement membrane, and dermis. The fragmentation of some of these host proteins suggests that breaching of host defenses by cercariae includes specific degradation of immunoglobulins and complement, and either degradation of, or overwhelming the host protease inhibitor repertoire

Structures of falcipain-2 and falcipain-3 bound to small molecule inhibitors: implications for substrate specificity.

Falcipain-2 and falcipain-3 are critical hemoglobinases of Plasmodium falciparum, the most virulent human malaria parasite. We have determined the 2.9 A crystal structure of falcipain-2 in complex with the epoxysuccinate E64 and the 2.5 A crystal structure of falcipain-3 in complex with the aldehyde leupeptin. These complexes represent the first crystal structures of plasmodial cysteine proteases with small molecule inhibitors and the first reported crystal structure of falcipain-3. Our structural analyses indicate that the relative shape and flexibility of the S2 pocket are affected by a number of discrete amino acid substitutions. The cumulative effect of subtle differences, including those at "gatekeeper" positions, may explain the observed kinetic differences between these two closely related enzymes

3D Ultrastructural Imaging of Chromosomes Using Serial Block-Face Scanning Electron Microscopy (SBFSEM)

To date, our understanding of how DNA is packaged in the cell nucleus, condensed from chromatin into chromosomes, and organized throughout the cell cycle remains sparse. Three dimensional (3D) ultrastructural imaging is an important tool for unravelling the organizational structure of chromosomes. For large volume 3D imaging of biological samples, serial block-face scanning electron microscopy (SBFSEM) has been applied, whereby ultrastructural information is achieved by analyzing 3D reconstructions acquired from measured data sets. In this review, we summarize the contribution of SBFSEM for obtaining 3D images of chromosomes to investigate their ultrastructure and organization in the cell and its nucleus. Furthermore, this review highlights the potential of SBFSEM for advancing 3D chromosome research

Basal Cell Carcinomas in Gorlin Syndrome: A Review of 202 Patients

Gorlin syndrome (Naevoid Basal Cell Carcinoma Syndrome) is a rare autosomal dominant syndrome caused by mutations in the PTCH gene with a birth incidence of approximately 1 in 19,000. Patients develop multiple basal cell carcinomas of the skin frequently in early life and also have a predisposition to additional malignancies such as medulloblastoma. Gorlin Syndrome patients also have developmental defects such as bifid ribs and other complications such as jaw keratocysts. We studied the incidence and frequency of basal cell carcinomas in 202 Gorlin syndrome patients from 62 families and compared this to their gender and mutation type. Our data suggests that the incidence of basal cell carcinomas is equal between males and females and the mutation type cannot be used to predict disease burden

Assessment the Immunohistochemical Expression of Wild BRAF and Mutant BRAFV600E in Iraqi Patients with Colorectal Carcinoma

In the current study hundred ten of Iraqi patients with colorectal tumors were studied to evaluate the expressionof wild BRAF and BRAFV600E using Tissue microarray-Immunohistochemisty (TMA-IHC) technique. Of them,Ninety cases had colorectal carcinoma, and twenty had benign tumors. A group of twenty cases of non-specificcolitis and other twenty colonic biopsies with no significant pathology were also studied. Results of the studydemonstrated that BRAF expression was positive in 86.7% of carcinoma cases, and there was significantdifferences (P=0.038) in the expression of BRAF within tumor stages. Whereas BRAFV600E expression wasnegative in groups of adenoma, colitis and cases with no significant pathology compared to carcinoma group inwhich 13.3% showed positive expression. We found significant correlation between the expression ofBRAFV600E and the age (P=0.047), right sided colon tumor (P=0.041), and mucinous type carcinoma (P=0.021).And there was significant differences between wild BRAF and mutant BRAFV600E in age, female gender, rightsidedcolon tumor, tumor grade, and type of tumor (p=0.0001).Keywords: BRAF, mutant BRAF, CRC, prognostic markers in CRC

Contribution of advanced fluorescence nano microscopy towards revealing mitotic chromosome structure

The organization of chromatin into higher-order structures and its condensation process represent one of the key challenges in structural biology. This is important for elucidating several disease states. To address this long-standing problem, development of advanced imaging methods has played an essential role in providing understanding into mitotic chromosome structure and compaction. Amongst these are two fast evolving fluorescence imaging technologies, specifically fluorescence lifetime imaging (FLIM) and super-resolution microscopy (SRM). FLIM in particular has been lacking in the application of chromosome research while SRM has been successfully applied although not widely. Both these techniques are capable of providing fluorescence imaging with nanometer information. SRM or nanoscopy is capable of generating images of DNA with less than 50 nm resolution while FLIM when coupled with energy transfer may provide less than 20 nm information. Here, we discuss the advantages and limitations of both methods followed by their contribution to mitotic chromosome studies. Furthermore, we highlight the future prospects of how advancements in new technologies can contribute in the field of chromosome science