Strong larvicidal potential of Artemisia annua leaf extract against malaria (Anopheles stephensi Liston) and dengue (Aedes aegypti L.) vectors and bioassay-driven isolation of the marker compounds

Malaria and dengue are the two most important vector-borne human diseases caused by mosquito vectors Anopheles stephensi and Aedes aegypti, respectively. Of the various strategies adopted for eliminating these diseases, controlling of vectors through herbs has been reckoned as one of the important measures for preventing their resurgence. Artemisia annua leaf chloroform extract when tried against larvae of A. stephensi and A. aegypti has shown a strong larvicidal activity against both of these vectors, their respective LC50 and LC90 values being 0.84 and 4.91 ppm for A. stephensi and 0.67 and 5.84 ppm for A. aegypti. The crude extract when separated through column chromatography using petroleum ether-ethyl acetate gradient (0–100 %) yielded 76 fractions which were pooled into three different active fractions A, B and C on the basis of same or nearly similar R _f values. The aforesaid pooled fractions when assayed against the larvae of A. stephensi too reported a strong larvicidal activity. The respective marker compound purified from the individual fractions A, B and C, were Artemisinin, Arteannuin B and Artemisinic acid, as confirmed and characterized through FT-IR and NMR. This is our first report of strong mortality of A. annua leaf chloroform extract against vectors of two deadly diseases. This technology can be scaled up for commercial exploitation.     

Genetic Study of an Indian Family with Cherubism

Cherubism (OMIM : 118400) is an autosomal dominant disorder affecting mainly facial bones leading to disfigurement of face needing medical and surgical attention besides impairing the self esteem of person. At present, there is no medical cure and there is limited indication for surgery in such cases. So, correct diagnosis is of paramount importance to both treating physician and family. Here, the authors report a family with two affected members (mother and daughter) who were tested positive for a known pathogenic mutation and thus offered timely treatment and adequate genetic counseling.     

CDC Kerala 15: Developmental Evaluation Clinic (2–10 y) – Developmental Diagnosis and Use of Home Intervention Package

Objective

To describe the last 5 years' experience of Child Development Centre (CDC), Kerala Developmental Evaluation Clinic II for children between 2 and 10 y, referred for suspicion of developmental lag in the preschool years and scholastic difficulty in the primary classes with specific focus on developmental profile and the experience of the home based intervention package taught to the mothers.

Methods

A team of evaluators including developmental therapist, preschool teacher with special training in clinical child development, speech therapist, special educator, clinical psychologist and developmental pediatrician assessed all the children referred to CDC Kerala. Denver Developmental Screening Test (DDST-II), Vineland Social Maturity Scale (VSMS) and Intelligent Quotient (IQ) tests were administered to all children below 6 y and those above 6 with apparent developmental delay.

Results

Speech/delay (35.9 %), behavior problem (15.4 %), global delay/ intellectual disability (15.4 %), learning problem (10.9 %), pervasive developmental disorders (7.7 %), seizure disorder (1.7 %), hearing impairment (0.7 %), and visual impairment (0.7 %) were the clinical diagnosis by a developmental pediatrician. Each child with developmental problem was offered a home based intervention package consisting of developmental therapy and special education items, appropriate to the clinical diagnosis of the individual child and the same was taught to the mother.

Conclusions

The experience of conducting the developmental evaluation clinic for children between 2 and 10 y has shown that a team consisting of developmental therapist, speech therapist, preschool teacher, special educator, clinical child psychologist and developmental pediatrician, using appropriate test results of the child could make a clinical diagnosis good enough for providing early intervention therapy using a home based intervention package.

     

Establishing national neonatal perinatal database and birth defects registry network — Need of the hour!

Early detection and prevention of birth defects is necessary to further reduce neonatal morbidity and mortality. A birth defect registry or surveillance system is necessary to assess the exact magnitude, profile and modifiable risk factors for birth defects. We review the existing efforts and suggest possible options for addressing this important issue. Connecting birth defects registry with the pre-existing programs such as National Neonatal Perinatal Database could be one of the option.     

Molecular architecture of the αβ T cell receptor–CD3 complex

αβ T-cell receptor (TCR) activation plays a crucial role for T-cell function. However, the TCR itself does not possess signaling domains. Instead, the TCR is noncovalently coupled to a conserved multisubunit signaling apparatus, the CD3 complex, that comprises the CD3εγ, CD3εδ, and CD3ζζ dimers. How antigen ligation by the TCR triggers CD3 activation and what structural role the CD3 extracellular domains (ECDs) play in the assembled TCR–CD3 complex remain unclear. Here, we use two complementary structural approaches to gain insight into the overall organization of the TCR–CD3 complex. Small-angle X-ray scattering of the soluble TCR–CD3εδ complex reveals the CD3εδ ECDs to sit underneath the TCR α-chain. The observed arrangement is consistent with EM images of the entire TCR–CD3 integral membrane complex, in which the CD3εδ and CD3εγ subunits were situated underneath the TCR α-chain and TCR β-chain, respectively. Interestingly, the TCR–CD3 transmembrane complex bound to peptide–MHC is a dimer in which two TCRs project outward from a central core composed of the CD3 ECDs and the TCR and CD3 transmembrane domains. This arrangement suggests a potential ligand-dependent dimerization mechanism for TCR signaling. Collectively, our data advance our understanding of the molecular organization of the TCR–CD3 complex, and provides a conceptual framework for the TCR activation mechanism.T cells are key mediators of the adaptive immune response. Each αβ T cell contains a unique αβ T-cell receptor (TCR), which binds antigens (Ags) displayed by major histocompatibility complexes (MHCs) and MHC-like molecules (1). The TCR serves as a remarkably sensitive driver of cellular function: although TCR ligands typically bind quite weakly (1–200 μM), even a handful of TCR ligands are sufficient to fully activate a T cell (2, 3). The TCR does not possess intracellular signaling domains, uncoupling Ag recognition from T-cell signaling. The TCR is instead noncovalently associated with a multisubunit signaling apparatus, consisting of the CD3εγ and CD3εδ heterodimers and the CD3ζζ homodimer, which collectively form the TCR–CD3 complex (4, 5). The CD3γ/δ/ε subunits each consist of a single extracellular Ig domain and a single immunoreceptor tyrosine-based activation motif (ITAM), whereas CD3ζ has a short extracellular domain (ECD) and three ITAMs (6–11). The TCR–CD3 complex exists in 1:1:1:1 stoichiometry for the αβTCR:CD3εγ:CD3εδ:CD3ζζ dimers (12). Phosphorylation of the intracellular CD3 ITAMs and recruitment of the adaptor Nck lead to T-cell activation, proliferation, and survival (13, 14). Understanding the underlying principles of TCR–CD3 architecture and T-cell signaling is of therapeutic interest. For example, TCR–CD3 is the target of therapeutic antibodies such as the immunosuppressant OKT3 (15), and there is increasing interest in manipulating T cells in an Ag-dependent manner by using naturally occurring and engineered TCRs (16).Assembly of the TCR–CD3 complex is primarily driven by each protein’s transmembrane (TM) region, enforced through the interaction of evolutionarily conserved, charged, residues in each TM region (4, 5, 12). What, if any, role interactions between TCR and CD3 ECDs play in the assembly and function of the complex remains controversial (5): there are several plausible proposed models of activation, which are not necessarily mutually exclusive (5, 17–19). Although structures of TCR–peptide–MHC (pMHC) complexes (2), TCR–MHC-I–like complexes (1), and the CD3 dimers (6–10) have been separately determined, how the αβ TCR associates with the CD3 complex is largely unknown. Here, we use two independent structural approaches to gain an understanding of the TCR–CD3 complex organization and structure.