Designing novel inhibitors against falcipain-2 of Plasmodium falciparum

Coumarin containing pyrazoline derivatives have been synthesized and tested as inhibitors of in vitro development of a chloroquine-sensitive (MRC-02) and chloroquine-resistant (RKL-2) strain of Plasmodium falciparum and in vivo Plasmodium berghei malaria. Docking study was also done on cysteine protease falcipain-2 which showed that the binding pose of C-14 molecule and epoxysuccinate, inhibitor of falcipain-2, binds in the similar pattern. The most active antimalarial compound was 3-(1-benzoyl-5-(4-flurophenyl)-4,5-dihydro-1H-pyrazol-3yl)-7-(diethyamino)-2H-chromen-2-one C-14, with an IC₅₀ of 4.21?µg/ml provided complete protection to the infected mice at 24?mg/kg X 4?days respectively.     

Hydrophilic Acylated Surface Protein A (HASPA) of <Emphasis Type="Italic">Leishmania donovani</Emphasis>: Expression,Purification and Biophysico-Chemical Characterization

Hydrophilic acylated surface proteins (HASPs) are acidic surface proteins which get localized on the surface of Leishmania parasite during infective stages through a “non-classical” pathway. In this study, we report the heterologous expression and purification of Leishmania donovani HASPA (r-LdHASPA) in E. coli system and its partial characterization. The structural aspects of the purified protein were analyzed using CD spectroscopy and modeling studies which indicate that r-LdHASPA consists of random coils. Studies in mouse macrophage RAW264.7 cell lines indicate that r-LdHASPA enhances reactive oxygen species (ROS) production. Co-immunoprecipitation (IP) studies indicate that r-LdHASPA interacts with certain macrophage proteins which however could not be identified unambiguously. The present study provides key insights into the structural and functional aspects of an important Leishmania protein, HASPA, which we believe could be useful for further research on vaccine/drug development.     

Emergence of deciduous teeth in Punjabi children, north India.

Data on deciduous tooth emergence of 312 children aged 4 to 31 months of Punjabi parentage are presented. Probit analysis was used to derive the median age of tooth emergence. Female children are found to be advanced with respect to tooth emergence than their male counterparts. While comparing the present data with those from other populations it is found that, in general, the mean number of emerged teeth in Punjabi children is more at most ages, with lower median age of eruption for most teeth. Magnitude of interage variability in the eruption times is noticed to be maximum in the 16-17 and 20-21 months age groups. The findings of the study suggest that number of teeth can be used as a parameter for the estimation of age.     

2-Amino-9H-pyrido[2,3-b]indole (AαC) Adducts and Thiol Oxidation of Serum Albumin as Potential Biomarkers of Tobacco Smoke

2-Amino-9H-pyrido[2,3-b]indole (AαC) is a carcinogenic heterocyclic aromatic amine formed during the combustion of tobacco. AαC undergoes bioactivation to form electrophilic N-oxidized metabolites that react with DNA to form adducts, which can lead to mutations. Many genotoxicants and toxic electrophiles react with human serum albumin (albumin); however, the chemistry of reactivity of AαC with proteins has not been studied. The genotoxic metabolites, 2-hydroxyamino-9H-pyrido[2,3-b]indole (HONH-AαC), 2-nitroso-9H-pyrido[2,3-b]indole (NO-AαC), N-acetyloxy-2-amino-9H-pyrido[2,3-b]indole (N-acetoxy-AαC), and their [¹³C₆]AαC-labeled homologues were reacted with albumin. Sites of adduction of AαC to albumin were identified by data-dependent scanning and targeted bottom-up proteomics approaches employing ion trap and Orbitrap MS. AαC-albumin adducts were formed at Cys³⁴, Tyr¹⁴⁰, and Tyr¹⁵⁰ residues when albumin was reacted with HONH-AαC or NO-AαC. Sulfenamide, sulfinamide, and sulfonamide adduct formation occurred at Cys³⁴ (AαC-Cys³⁴). N-Acetoxy-AαC also formed an adduct at Tyr³³². Albumin-AαC adducts were characterized in human plasma treated with N-oxidized metabolites of AαC and human hepatocytes exposed to AαC. High levels of N-(deoxyguanosin-8-yl)-AαC (dG-C8-AαC) DNA adducts were formed in hepatocytes. The Cys³⁴ was the sole amino acid of albumin to form adducts with AαC. Albumin also served as an antioxidant and scavenged reactive oxygen species generated by metabolites of AαC in hepatocytes; there was a strong decrease in reduced Cys³⁴, whereas the levels of Cys³⁴ sulfinic acid (Cys-SO₂H), Cys³⁴-sulfonic acid (Cys-SO₃H), and Met³²⁹ sulfoxide were greatly increased. Cys³⁴ adduction products and Cys-SO₂H, Cys-SO₃H, and Met³²⁹ sulfoxide may be potential biomarkers to assess exposure and oxidative stress associated with AαC and other arylamine toxicants present in tobacco smoke.     

Aspergillosis in German cockroach Blattella germanica (L.) (Blattoidea: Blattellidae)

Natural infection of Aspergillus flavus was observed in adults of Blattella germanica. Though the adult insects exhibited no external symptoms, they became hypoactive and later died. The dead and experimentally infected insects repeatedly yielded Aspergillus flavus in culture on Czapek's medium. Direct microscopic observation of the tissues of infected insects revealed fungal material. The blood films stained with Giemsa stain showed granulocytes (GRs) engulfing fungal hyphae. A remarkable increase in GR and plasmatocyte (PL) counts occurred in differential haemocyte counts (DHCs) of the infected insects. Two main types of immunological responses of the insect noticed were phagocytosis and encapsulation. DHC showed maximum involvement of GRs and PLs in immune mechanism. This revised version was published online in June 2006 with corrections to the Cover Date.     

Characterization of Novel Lipopeptides Produced by Bacillus tequilensis P15 Using Liquid Chromatography Coupled Electron Spray Ionization Tandem Mass Spectrometry (LC–ESI–MS/MS)

Microbes are known to interact and communicate with their neighbouring cells by releasing diverse types of low molecular weight diffusible metabolites. This paper describes the identification of iturins, fengycins and surfactins secreted by Bacillus tequilensis P15 isolated from sea coast of Jakhao, Kutch, India, using liquid chromatography coupled electron spray ionization tandem mass spectrometry. In methanol soluble fraction of acid precipitate harvested from cell free supernatant of B. tequilensis P15, 5 variants of iturins, 6 of fengycins and 39 surfactins could be identified. In particular, new surfactins with Ile/Leu at position 5 and Asp at position 6 in the peptide chain were discovered, which have not been previously reported. A novel class of novel surfactin consisting of Glu/methyl ester of Asp at position 5 in peptide chain was also identified. In addition, several linear forms of surfactins were also identified in the methanol soluble extracellular fraction of B. tequilensis P15. This is the first report on co-production of all the three classes of cyclic lipopeptides by a marine isolate B. tequilensis.     

Using a non-radioisotopic, quantitative TRAP-based method detecting telomerase activities in human hepatoma cells

INTRODUCTIONTelomerase is a ribonucleoprotein complex that plays a critical role in telomeremaintenance and cellular immortality. Telomerase has been considered as tumordiagnostic marker and potential target for cancer therapyll, 2]. A sensitive, reliableand quantitative assay is of high interest in this field. The development of a very sensitive Telomeric Repeat Amplification Protocol (TRAP) for measuring telomerajseactivity in cell extracts has been proved to be an important tool for…     

Effects of plant extract Centella asiatica (Linn.) on cold restraint stress ulcer in rats.

Extract of C. asiatica (Linn.) inhibited significantly gastric ulceration induced by cold and restraint stress (CRS) in Charles-Foster rats, Antiulcer activity of plant extract was compared with famotidine (H2-antagonist) and sodium valproate (anti-epileptic). Plant extract, formotidine and sodium valproate showed a dose dependent reduction of gastric ulceration. Plant extract increased brain GABA level which was also dose dependent. Pretreatment with bicuculline methiodide (specific GABAA-antagonist) at the dose level of 0.5 mg/kg im, reversed the antiulcerogenic activity of both plant extract and sodium valproate. Bicuculline as such did not induce gastric ulceration in normal rat.     

脊椎动物Argonaute蛋白的研究进展

Argonaute蛋白是广泛活跃于不同生物的整个生命周期、与小RNA (small RNA, sRNA)结合并调控基因表达的一类蛋白。脊椎动物Argonaute蛋白有2个分支,Ago蛋白和Piwi蛋白,均包含N、L1、L2、PAZ、MID和PIWI结构域。N结构域有助于sRNA单链加载;L1、L2起结构域连接作用;PAZ和MID结构域通过锚定sRNA发挥功能;部分Argonaute蛋白的PIWI结构域类似RNase H,具有核酸内切酶功能。Ago蛋白主要在转录及转录后水平调控基因表达;Piwi蛋白主要存在于生殖细胞,通过多种途径沉默转座子以保护机体基因组免受破坏,同时参与基因表达调控。本文结合近年来Argonaute蛋白在晶体结构、功能解析、表达模式等方面的研究进展,从蛋白结构、sRNA依赖性、基因表达调控机制、生物学功能等方面对脊椎动物Ago和Piwi蛋白分支进行比较阐述,以期阐明其在表观遗传调控中的作用,并为后续Argonaute蛋白的深入研究和实际应用提供参考。