Rotifer Species Assemblages in Three Freshwater Habitats of Manipur,India

The present commentary deals with the diversity of rotifers from three different habitats that include a river, lake and an irrigation canal from Manipur, India. Using the samples (n = 288) spanning over a 2-year period the species richness and the abundance of rotifers were assessed. A total of 34 species of rotifers from 11 families were observed with varying relative abundance, with the diversity indices (Shannon–Wiener, H’) ranging between 2.98 and 3.23. The species composition of the three habitats differed considerably, as evident from the multivariate analysis. In the lake habitat, the dominant species was Brachionus calyciflorus (7.9%), while in the irrigation canal the dominant species was Brachionus ruben (10.4%), and for the river habitat the dominant species was B. calyciflorus (11.5%). Using relative abundance of the rotifer species as explanatory variables, the ordination of the 34 species yielded significant differences based on the similarity in the abundance over the sampling period. On the basis of the overall differences in the species composition of rotifers, the three habitats could be segregated significantly (P < 0.05) based on the discriminant function analysis. Although the species composition of rotifers remained similar to other freshwater bodies of the this geographical region, the diversity and community analysis suggested considerable differences with reference to the three habitats, implying significance for limnological management.     

Is Using the Strengths and Difficulties Questionnaire in a Community Sample the Optimal Way to Assess Mental Health Functioning?

An important characteristic of a screening tool is its discriminant ability or the measure’s accuracy to distinguish between those with and without mental health problems. The current study examined the inter-rater agreement and screening concordance of the parent and teacher versions of SDQ at scale, subscale and item-levels, with the view of identifying the items that have the most informant discrepancies; and determining whether the concordance between parent and teacher reports on some items has the potential to influence decision making. Cross-sectional data from parent and teacher reports of the mental health functioning of a community sample of 299 students with and without disabilities from 75 different primary schools in Perth, Western Australia were analysed. The study found that: a) Intraclass correlations between parent and teacher ratings of children’s mental health using the SDQ at person level was fair on individual child level; b) The SDQ only demonstrated clinical utility when there was agreement between teacher and parent reports using the possible or 90% dichotomisation system; and c) Three individual items had positive likelihood ratio scores indicating clinical utility. Of note was the finding that the negative likelihood ratio or likelihood of disregarding the absence of a condition when both parents and teachers rate the item as absent was not significant. Taken together, these findings suggest that the SDQ is not optimised for use in community samples and that further psychometric evaluation of the SDQ in this context is clearly warranted.     

Association of genetic and non-genetic risk factors with the development of prostate cancer in Malaysian men

There is growing global interest to stratify men into different levels of risk to developing prostate cancer, thus it is important to identify common genetic variants that confer the risk. Although many studies have identified more than a dozen common genetic variants which are highly associated with prostate cancer, none have been done in Malaysian population. To determine the association of such variants in Malaysian men with prostate cancer, we evaluated a panel of 768 SNPs found previously associated with various cancers which also included the prostate specific SNPs in a population based case control study (51 case subjects with prostate cancer and 51 control subjects) in Malaysian men of Malay, Chinese and Indian ethnicity. We identified 21 SNPs significantly associated with prostate cancer. Among these, 12 SNPs were strongly associated with increased risk of prostate cancer while remaining nine SNPs were associated with reduced risk. However, data analysis based on ethnic stratification led to only five SNPs in Malays and 3 SNPs in Chinese which remained significant. This could be due to small sample size in each ethnic group. Significant non-genetic risk factors were also identified for their association with prostate cancer. Our study is the first to investigate the involvement of multiple variants towards susceptibility for PC in Malaysian men using genotyping approach. Identified SNPs and non-genetic risk factors have a significant association with prostate cancer.     

Plants fabricate Fe-nanocomplexes at root surface to counter and phytostabilize excess ionic Fe

While evaluating the impact of iron nanoparticles (NPs) on terrestrial plants we realized potential of root system of intact plants to form orange–brown complexes constituted of NPs around their roots and at bottom/side of tubes when exposed to FeCl₃. These orange–brown complexes/plaques seen around roots were similar to that reported in wetland plants under iron toxicity. Transmission electron microscopy coupled with energy dispersive X-ray analysis revealed that orange–brown complexes/plaques, formed by root system of all 16 plant species from 11 distinct families tested, were constituted of NPs containing Fe. Selected area electron diffraction and powder X-ray diffraction spectra showed their amorphous nature. Thermogravimetric and fourier transform infra-red analysis showed that these Fe-NPs/nanocomplexes were composed of iron-oxyhydroxide. These plant species generated orange–brown Fe-NPs/nanocomplexes even under strict sterile conditions establishing inbuilt and independent potential of their root system to generate Fe-NPs. Root system of intact plants showed ferric chelate reductase activity responsible for reduction of Fe³⁺ to Fe²⁺. Reduction of potassium ferricyanide by root system of intact plants confirmed that root surface possess strong reducing strength, which could have played critical role in reduction of Fe³⁺ and formation of Fe-NPs/nanocomplexes. Atomic absorption spectrophotometric analysis revealed that majority of iron was retained in Fe-nanocomplexes/plaques, while only 2–3 % was transferred to shoots, indicating formation of nanocomplexes is a phytostabilization mechanism evolved by plants to restrict uptake of iron above threshold levels. We believe that formation of Fe-NPs/nanocomplexes is an ideal homeostasis mechanism evolved by plants to modulate uptake of desired levels of ionic Fe.     

Interferon Regulatory Factor-1 Protects from Fatal Neurotropic Infection with Vesicular Stomatitis Virus by Specific Inhibition of Viral Replication in Neurons

The innate immune system protects cells against invading viral pathogens by the auto- and paracrine action of type I interferon (IFN). In addition, the interferon regulatory factor (IRF)-1 can induce alternative intrinsic antiviral responses. Although both, type I IFN and IRF-1 mediate their antiviral action by inducing overlapping subsets of IFN stimulated genes, the functional role of this alternative antiviral action of IRF-1 in context of viral infections in vivo remains unknown. Here, we report that IRF-1 is essential to counteract the neuropathology of vesicular stomatitis virus (VSV). IFN- and IRF-1-dependent antiviral responses act sequentially to create a layered antiviral protection program against VSV infections. Upon intranasal infection, VSV is cleared in the presence or absence of IRF-1 in peripheral organs, but IRF-1^−/− mice continue to propagate the virus in the brain and succumb. Although rapid IFN induction leads to a decline in VSV titers early on, viral replication is re-enforced in the brains of IRF-1^−/− mice. While IFN provides short-term protection, IRF-1 is induced with delayed kinetics and controls viral replication at later stages of infection. IRF-1 has no influence on viral entry but inhibits viral replication in neurons and viral spread through the CNS, which leads to fatal inflammatory responses in the CNS. These data support a temporal, non-redundant antiviral function of type I IFN and IRF-1, the latter playing a crucial role in late time points of VSV infection in the brain.     

INDeGenIUS,a new method for high-throughput identification of specialized functional islands in completely sequenced organisms

Genomic islands (GIs) are regions in the genome which are believed to have been acquired via horizontal gene transfer events and are thus likely to be compositionally distinct from the rest of the genome. Majority of the genes located in a GI encode a particular function. Depending on the genes they encode, GIs can be classified into various categories, such as ‘metabolic islands’, ‘symbiotic islands’, ‘resistance islands’, ‘pathogenicity islands’, etc. The computational process for GI detection is known and many algorithms for the same are available. We present a new method termed as Improved N-mer based Detection of Genomic Islands Using Sequence-clustering (INDeGenIUS) for the identification of GIs. This method was applied to 400 completely sequenced species belonging to proteobacteria. Based on the genes encoded in the identified GIs, the GIs were grouped into 6 categories: metabolic islands, symbiotic islands, resistance islands, secretion islands, pathogenicity islands and motility islands. Several new islands of interest which had previously been missed out by earlier algorithms were picked up as GIs by INDeGenIUS. The present algorithm has potential application in the identification of functionally relevant GIs in the large number of genomes that are being sequenced. Investigation of the predicted GIs in pathogens may lead to identification of potential drug/vaccine candidates.     

Suppression of UVA-mediated release of labile iron by epicatechin--a link to lysosomal protection

UVA (320-380 nm) radiation generates an oxidative stress in cells and leads to an immediate release of potentially damaging labile iron pools in human skin cells. Treatment of cultured skin fibroblasts for several hours with physiologically relevant concentrations of either epicatechin (EC), a flavonoid plant constituent present in foods, or methylated epicatechin (3'-O-methyl epicatechin, MeOEC), its major human metabolite, prevents this iron release. The similarity of the effectiveness of EC and MeOEC argues against chelation as the mechanism of iron removal. Evidence based on measurements of lysosomal integrity strongly supports the hypothesis that the catechins protect against lysosomal destruction by UVA. Such damage would normally lead to protease release, which has been previously shown to cause ferritin degradation and release of labile iron.     

99mTc-labeling of colchicine using [99mTc(CO)3(H2O)3]+ and [99mTc triple bond N]2+ core for the preparation of potential tumor-targeting agents

Multidrug resistance (MDR) mediated by over-expression of P-glycoprotein (Pgp) is one of the major causes of failure of chemotherapy in cancer treatment. Colchicine, a naturally occurring alkaloid, is a Pgp substrate and acts as an antimitotic agent by binding to microtubules. Hence, Colchicine and its analogues radiolabeled with 99mTc may have potential for visualization of MDR in tumors. Here we report 99mTc-labeling of colchicine derivatives using [99mTc(CO)3(H2O)3]+ and [99mTc triple bond N]2+ cores. Trimethylcolchicinic acid synthesized from colchicine was used as the precursor to prepare iminodiacetic acid and dithiocarbamate derivatives which were then radiolabeled with [99mTc(CO)3(H2O)3]+ and [99mTc triple bond N]2+ cores, respectively. Radiolabeling yield for both the complexes was > 98% as observed by HPLC and TLC patterns. In vitro studies in tumor cell lines showed significant uptake for 99mTc-carbonyl as well as for 99mTc-nitrido colchicine complexes. Biodistribution studies in Swiss mice bearing fibrosarcoma tumor showed 4.1 +/- 1.2% ID/g of uptake at 30 min pi for 99mTc(CO)3-complex as against 0.42 +/- 0.24% ID/g for the 99mTcN-complex. 99mTc(CO)3-colchicine complex exhibited better pharmacokinetics with lower liver accumulation as compared to the 99mTcN-complex. Thus, colchicine radiolabeled with [99mTc(CO)3(H2O)3]+ core is more promising with respect to in vivo distribution characteristics in tumor model.