Novel aromatic polyketides from soil <Emphasis Type="Italic">Streptomyces</Emphasis> spp.: purification,characterization and bioactivity studies

Aromatic polyketides are important therapeutic compounds which include front line antibiotics and anticancer drugs. Since most of the aromatic polyketides are known to be produced by soil dwelling Streptomyces, 54 Streptomyces strains were isolated from the soil samples. Five isolates, R1, B1, R3, R5 and Y8 were found to be potent aromatic polyketide producers and were identified by 16S rRNA gene sequencing as Streptomyces spectabilis, Streptomyces olivaceus, Streptomyces purpurascens, Streptomyces coeruleorubidus and Streptomyces lavendofoliae respectively. Their sequences have been deposited in the GenBank under the accession numbers KF468818, KF681280, KF395224, KF527511 and KF681281 respectively. The Streptomyces strains were cultivated in the media following critically optimised culture conditions. The resulting broth extracts were fractionated on a silica gel column and preparative TLC to obtain pure compounds. The pure compounds were tested for bioactivity and the most potent compound from each isolate was identified by UV–Vis, IR and NMR spectroscopic methods. Isolated S. spectabilis (R1), yielded one potent compound identified as dihydrodaunomycin with an MIC of 4 µg/ml against Bacillus cereus and an IC₅₀ value of 24 µM against HeLa. S. olivaceus (B1), yielded a comparatively less potent compound, elloramycin. S. purpurascens (R3) yielded three compounds, rhodomycin, epelmycin and obelmycin. The most potent compound was rhodomycin with an MIC of 2 µg/ml against B. cereus and IC₅₀ of 15 µM against HeLa. S. coeruleorubidus (R5), yielded daunomycin showing an IC₅₀ of 10 µM and also exhibiting antimetastatic properties against HeLa. S. lavendofoliae (Y8), yielded a novel aclacinomycin analogue with IC₅₀ value of 2.9 µM and potent antimetastatic properties at 1 µM concentration against HeLa. The study focuses on the characterization of aromatic polyketides from soil Streptomyces spp., which can serve as potential candidates for development of chemotherapeutic drugs in future.     

Antimicrobial activity of <Emphasis Type="Italic">Alcaligenes sp</Emphasis>. HPC 1271 against multidrug resistant bacteria

Alcaligenes sp. HPC 1271 demonstrated antibacterial activity against multidrug resistant bacteria, Enterobacter sp., resistant to sulfamethoxazole, ampicillin, azithromycin, and tetracycline, as well as against Serratia sp. GMX1, resistant to the same antibiotics with the addition of netilmicin. The cell-free culture supernatant was analyzed for possible antibacterials by HPLC, and the active fraction was further identified by LC-MS. Results suggest the production of tunicamycin, a nucleoside antibiotic. The draft genome of this bacterial isolate was analyzed, and the 4.2 Mb sequence data revealed six secondary metabolite-producing clusters, identified using antiSMASH platform as ectoine, butyrolactone, phosphonate, terpene, polyketides, and nonribosomal peptide synthase (NRPS). Additionally, the draft genome demonstrated homology to the tunicamycin-producing gene cluster and also defined 30 ORFs linked to protein secretion that could also play a role in the antibacterial activity observed. Gene expression analysis demonstrated that both NRPS and dTDP-glucose 4,6-dehydratase gene clusters are functional and could be involved in antibacterial biosynthesis.     

Observed Measures of Negative Parenting Predict Brain Development during Adolescence

Limited attention has been directed toward the influence of non-abusive parenting behaviour on brain structure in adolescents. It has been suggested that environmental influences during this period are likely to impact the way that the brain develops over time. The aim of this study was to investigate the association between aggressive and positive parenting behaviors on brain development from early to late adolescence, and in turn, psychological and academic functioning during late adolescence, using a multi-wave longitudinal design. Three hundred and sixty seven magnetic resonance imaging (MRI) scans were obtained over three time points from 166 adolescents (11–20 years). At the first time point, observed measures of maternal aggressive and positive behaviors were obtained. At the final time point, measures of psychological and academic functioning were obtained. Results indicated that a higher frequency of maternal aggressive behavior was associated with alterations in the development of right superior frontal and lateral parietal cortical thickness, and of nucleus accumbens volume, in males. Development of the superior frontal cortex in males mediated the relationship between maternal aggressive behaviour and measures of late adolescent functioning. We suggest that our results support an association between negative parenting and adolescent functioning, which may be mediated by immature or delayed brain maturation.     

Impact of land use change on soil aggregate dynamics in the dry tropics

A 2‐year study was conducted to elucidate land use change (LUC) impact on the distribution of aggregate size fractions and associated carbon (C) concentration involving natural forest (NF), degraded forest (DF), cropland (CL), and biofuel plantation (JP, Jatropha plantation) in the dry tropical region of India across the soil profile (0–10, 10–20, and 20–30 cm). Across the seasons and the land uses, the proportion of macro‐ and microaggregates was maximum at upper and minimum at lower layer whereas mesoaggregates increase with depth. The trend of macro‐ and microaggregate fractions through the soil profile was NF > JP > DF > CL whereas that of mesoaggregates was CL > DF < JP > NF. Dry mean weight diameter was highest at upper layer and decreased down the depth in all the land uses and followed the trend NF > JP > DF > CL. Aggregate associated organic carbon (OC) concentration in all the fractions decreased from NF to DF, CL, or JP indicates that macroaggregate associated OC concentration was more susceptible to loss than that of meso‐ and microaggregate associated OC concentration. LUC induced decline in macroaggregate associated OC stock and increase in meso‐ and microaggregate associated OC stock; indicated redistribution of OC stock among aggregate fractions. It may be concluded that JP in dry tropics can be an efficient strategy for rehabilitation of degraded land as it improves aggregate structure and stability in the whole profile and aggregate associated OC stock in upper layer of soil.     

SP500263, a novel SERM,blocks osteoclastogenesis in a human bone cell model: role of IL-6 and GM-CSF

Bone metabolism requires tightly coupled activities exhibited by two unique cell populations, the bone-resorbing osteoclasts and the bone-forming osteoblasts. Imbalance in the function of these two cell types can result in osteoporosis, a condition characterized by loss in bone integrity and of bone mass. We developed a human bone cell culture model that allows the in vitro study of bone formation and osteoclastogenesis and employed this bone model for the screening and pharmacological analyses of protein and small molecule therapeutics. The cytokines, interleukin-6 (IL-6) and granulocyte macrophage colony stimulating factor (GM-CSF), play an intricate role in osteoclastogenesis in this system. Neutralizing antibodies to IL-6 and GM-CSF decreased the formation of osteoclast-like cells. SP500263, an early lead compound from a novel class of selective estrogen receptor modulators (SERMs), was more efficacious than estrogen and comparable to raloxifene in blocking cytokine production and formation of osteoclast-like cells. Our research demonstrates the usefulness of the in vitro co-culture model in the dissection of molecular events relevant to bone metabolism and provides greater insight into a potential novel role for cytokines in bone resorption. Furthermore, representatives of the SP500263 family of SERMs may be effective as therapeutics for the treatment of osteoporosis.     

Analysis of alcohol dependence phenotype in the COGA families using covariates to detect linkage

Linkage analysis methods that incorporate etiological heterogeneity of complex diseases are likely to demonstrate greater power than traditional linkage analysis methods. Several such methods use covariates to discriminate between linked and unlinked pedigrees with respect to a certain disease locus. Here we apply several such methods including two mixture models, ordered subset analysis, and a conditional logistic model to genome scan data on the DSM-IV alcohol dependence phenotype on the Collaborative Studies on Genetics of Alcoholism families, and compare the results to traditional nonparametric linkage analysis. In general, there was little agreement among the various covariate-based linkage statistics. Linkage signals with empirical p-values less than 0.001 were detected on chromosomes 3, 4, 7, 10, and 12, with the highest peak occurring at the GABRB1 gene using the ecb21 covariate.     

A genome-wide scan for loci affecting normal adult height in the Framingham Heart Study

OBJECTIVE: To map loci influencing normal adult height in 335 families from the Framingham Heart Study. METHODS: We analyzed data consisting of 1,702 genotyped individuals who have been followed over time. The first height measurement for individuals between the ages 20-55 years was analyzed in a genome-wide scan using variance component linkage analysis. Sex, age, and cohort effects were removed before analysis. RESULTS: Two regions (18pter-p11, 22q11.2) with multipoint LOD scores >1.0 (-log p values >2.0) were detected: we obtained LOD scores of 1.38 at D18S1364, and of 1.10 at D22S345. Analysis of height as a sex-limited phenotype revealed a peak in the 9p21 region near D9S319 with a maximum LOD score of 1.65 (-log p value >3.0) when only male height phenotypes were used. When only female phenotypes were used, a peak with a maximum LOD score of 1.85 (-log p value of 2.70) was observed in the 11q25-qter region near D11S2359. CONCLUSIONS: Our region of interest on chromosome 9 has been implicated by two prior studies. Variance components analysis appeared to be sensitive to pedigree structures as well as the method of IBD computation used.     

Understanding the Molecular Epidemiology and Global Relationships of Brachyspira hyodysenteriae from Swine Herds in the United States: A Multi-Locus Sequence Typing Approach

Outbreaks of mucohemorrhagic diarrhea in pigs caused by Brachyspira hyodysenteriae in the late 2000s indicated the re-emergence of Swine Dysentery (SD) in the U.S. Although the clinical disease was absent in the U.S. since the early 1990s, it continued to cause significant economic losses to other swine rearing countries worldwide. This study aims to fill the gap in knowledge pertaining to the re-emergence and epidemiology of B. hyodysenteriae in the U.S. and its global relationships using a multi-locus sequence typing (MLST) approach. Fifty-nine post re-emergent isolates originating from a variety of sources in the U.S. were characterized by MLST, analyzed for epidemiological relationships (within and between multiple sites of swine systems), and were compared with pre re-emergent isolates from the U.S. Information for an additional 272 global isolates from the MLST database was utilized for international comparisons. Thirteen nucleotide sequence types (STs) including a predominant genotype (ST93) were identified in the post re-emergent U.S. isolates; some of which showed genetic similarity to the pre re-emergent STs thereby suggesting its likely role in the re-emergence of SD. In the U.S., in general, no more than one ST was found on a site; multiple sites of a common system shared a ST; and STs found in the U.S. were distinct from those identified globally. Of the 110 STs characterized from ten countries, only two were found in more than one country. The U.S. and global populations, identified as clonal and heterogeneous based on STs, showed close relatedness based on amino acid types (AATs). One predicted founder type (AAT9) and multiple predicted subgroup founder types identified for both the U.S. and the global population indicate the potential microevolution of this pathogen. This study elucidates the strain diversity and microevolution of B. hyodysenteriae, and highlights the utility of MLST for epidemiological and surveillance studies.     

Glycosylphosphatidylinositol-specific phospholipase D influences triglyceride-rich lipoprotein metabolism

Glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) is a minor HDL-associated protein. Because many minor HDL-associated proteins exchange between different lipoprotein classes during the postprandial state and are also involved in triglyceride (TG) metabolism, we hypothesized that GPI-PLD may play a role in the metabolism of TG-rich lipoproteins. To test this hypothesis, we examined the distribution of GPI-PLD among lipoprotein classes during a fat tolerance test in C57BL/6 and LDL receptor-deficient (LDLR(-/-)) mice fed either a chow or high-fructose diet. In the fasting state in wild-type mice fed a chow diet, GPI-PLD was only present in HDL, whereas in LDLR(-/-) mice GPI-PLD was present in HDL and intermediate-density lipoproteins (IDL)/LDL. During the fat tolerance test, there was no change in total serum GPI-PLD levels in either model; however, a significant amount of GPI-PLD appeared in both VLDL (0.5-1% of total GPI-PLD) and IDL/LDL (5-10% of total GPI-PLD) in both models. The high-fructose diet increased both fasting and postprandial TG and serum GPI-PLD levels in both strains as well as the amount of GPI-PLD in VLDL. To determine whether GPI-PLD plays a direct role in TG metabolism, we increased liver GPI-PLD expression in C57BL/6 mice by adenovirus-mediated gene transfer, which resulted in a sevenfold increase in serum GPI-PLD levels. This change was associated with an increase in fasting (30%) and postprandial TG (50%) and a twofold reduction in TG-rich lipoprotein catabolism compared with saline or control adenovirus-treated mice. These studies demonstrate that GPI-PLD affects serum TG levels by altering catabolism of TG-rich lipoproteins.