Identification of the actinorhodin monomer and its related compound from a deletion mutant of the actVA-ORF4 gene of Streptomyces coelicolor A3(2)

An oxygenated derivative of dihydrokalafungin (DHK) was isolated from a deletion mutant of the actVA-ORF4 gene involved in the biosynthesis of a dimeric benzoisochromanequinone (BIQ) antibiotic, actinorhodin (ACT), in Streptomyces coelicolor A3(2). Spectroscopic analysis elucidated its structure as 8-hydroxy-DHK, corresponding to the monomeric unit of ACT. Further metabolite analysis identified its related compound, clearly derived from the reduction of 8-hydroxy-DHK. The structures of these metabolites indicate the essential role of ActVA-ORF4 in ACT biosynthesis, specifically in dimerization of a BIQ intermediate via C-C bond formation.     

Lysing of fresh human tumor by a cytotoxic factor derived from autologous large granular lymphocytes independently of other known cytokines

Summary During interaction with autologous tumor cells large granular lymphocytes (LGL) of cancer patients released a soluble cytotoxic factor, termed LGL-derived cytotoxic factor, which mediated lysing of autologous fresh tumor cells. The cytotoxic factor was compared with purified human recombinant cytotoxic cytokines, including tumor necrosis factor (TNF), lymphotoxin (LT), interferon (IFN) , IFN, interleukin-1 (IL-1) and IL-2. The LGL cytotoxic factor exhibited cytotoxicity against autologous and allogeneic fresh human tumor cells in an 18-h⁵¹Cr-release assay, while these target cells were resistant to lysing by any of the recombinant cytokines. Mixtures of recombinant(r) TNF, rLT, rIFN, rIFN, rIL-1 and rIL-2 were still unable to produce cytotoxic effects on fresh human tumor cells. Treatment with monoclonal and polyclonal antibodies directed against rTNF, rLT, rIFN, rIFN, or rIL-1 did not inhibit the cytotoxic activity of LGL-derived cytotoxic factor against fresh human tumor cells. Even a mixture of all the antibodies was incapable of blocking the cytolytic activity of the factor to fresh human tumor cells. Furthermore, intact LGL-mediated lysing of autologous tumor cells was not inhibited by any of the antibodies. These results may indicate that a cytotoxic factor produced by LGL in response to autologous tumor cells mediates lysing of fresh human tumor cells independently of TNF, LT, IFN, IL-1 and IL-2.     

Suicidal Feelings Interferes with Help-Seeking in Bullied Adolescents

Purpose

Being bullied is associated with the manifestation of suicidal feelings, which sharply increase in middle(-late) adolescence. Whether or not bullied middle(-late) adolescents with suicidal feelings seek help is therefore a critical issue, given that help-seeking plays a key role in the prevention of suicide. The aim of the present study is to investigate the effects of bullying, suicidal feelings and the interaction between these two factors on help-seeking behavior in adolescents.

Methods

Japanese middle(-late) adolescents (aged 15–18 years; n = 9484) were studied using self-report questionnaires. The rate of adolescents who actually sought help was examined for bullying status and suicidal feelings.

Results

The rate of adolescents who sought help was significantly higher when they were bullied (p<0.001) and also when they had mild suicidal feelings (p<0.001), but not when they displayed serious suicidal feelings. In the case of adolescents who were bullied, however, having suicidal feelings significantly decreased the rate of help-seeking (OR = 0.47, p<0.05 and OR = 0.32, p = 0.002 for having mild and serious suicidal feelings, respectively). The decrease was remarkable when suicidal feelings were serious. Specifically, the decrease was significant in seeking help from peers and family members, who are the most frequent source of the help for adolescents, when they had serious suicidal feelings (OR = 0.21, p<0.01 and OR = 0.13, p<0.001, respectively).

Conclusions

Suicidal feelings may interfere with help-seeking behavior, which could be critical in suicide prevention in bullied middle(-late) adolescents.     

Are the Rates of Hypertension and Diabetes Higher in People from Lower Socioeconomic Status in Bangladesh? Results from a Nationally Representative Survey

ObjectiveA well-established belief regarding inequalities in health around the world is that hypertension and diabetes are higher in groups of lower socioeconomic status. We examined whether rates of hypertension, diabetes, and the coexistence of hypertension and diabetes are higher in people from a lower socioeconomic status than in those from a higher socioeconomic status in Bangladesh.MethodsWe investigated a nationally representative dataset from the 2011 Bangladesh Demographic and Health Survey with objective measures for hypertension and diabetes. A wealth index was constructed from data on household assets using principal components analysis. Chi-square tests and logistic regressions were performed to test the associations between wealth level, hypertension and diabetes.FindingsPeople from the highest wealth quintile were significantly more likely to have hypertension (Adjusted odds ratios [AOR] = 1.65, 95% confidence interval [CI] = 1.22-2.25), diabetes (AOR = 1.81, 95% CI = 1.21-2.71), and the coexistence of hypertension and diabetes (AOR = 2.17, 95% CI = 1.05-4.49) than people from the lowest wealth quintile. The odds of having hypertension, diabetes, and their coexistence were higher for older people, women, people who engaged in less physical labor, and people who were overweight and obese.ConclusionWealthier people, particularly people from the fourth and highest wealth quintiles, should be careful to avoid unhealthy lifestyles to prevent hypertension and diabetes. Health policy makers and planners are urged to target wealthier strata in terms of hypertension and diabetes initiatives while paying special attention to older people, women, people who engage in less physical labor, and individuals who are overweight.     

Rapid demonstration of diversity of sulfatide molecular species from biological materials by MALDI-TOF MS

By combining the partition method for enrichment of sulfatides without any chromatographic procedures and the preparation method of lysosulfatides, we succeeded in analyzing these sulfated glycosphingolipids from biological materials by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) to reduce the complexity of mass fragmentation patterns within a day. We found that sulfated GalCer (HSO3-3Gal beta 1Cer) (SM4s [galactosylsulfatide]) was composed of different species. While composition of SM4s specifically depended on source materials, it always contained hydroxy fatty acids of various degrees. In addition to the common sphingoid 4-sphingenine (d18:1), uncommon/unusual sphingoids phytosphingosine (4-hydroxysphinganine) (t18:0), eicosasphinganine (d20:0), 4-eicosasphingenine (d20:1), and sphingadienine (d18:2) were easily detected. Finally, in addition to SM4s, sulfatide sulfated LacCer (HSO3-3Gal beta 4Glc beta 1Cer) (SM3 [sulfated lactosylceramide]) and sulfated Gg3Cer (GalNAc beta 4(HSO3-3)Gal beta 4Glc beta 1Cer) (SM2 [sulfated gangliotriaosylceramide]) were clearly detected in renal tubule cells. The major SM4s was composed of ceramides possessing d18:1 with C22 hydroxy fatty acids (C22:0 h), C23:0 h, and C24:0 h, whereas the major SM3/SM2 were composed of ceramides possessing t18:0 with C22 normal fatty acids (C22:0), C23:0, C24:0. Namely, in these two series of sulfatides, either fatty acids or sphingoids were hydroxylated, and chain lengths of these components were exactly the same, consequently resulting in a similar polarity of ceramide moieties in these sulfatide species. These results demonstrated diversities of sulfatide molecular species, not only with respect to sugar moieties but also to ceramide moieties, which are probably important for specific effective functions in particular microenvironments such as lipid membrane microdomains.     

Evaluation of dynamic features of Escherichia coli 16S ribosomal RNA in homogeneous physiological solution

There is no methodology for the estimation of the dynamic features of large-molecular-weight RNAs in homogeneous physiological media. In this report, a luminescence anisotropy-based method using a long-lifetime luminescent oligonucleotide probe for the estimation of the dynamic features of large-molecular-weight RNA is described. As a luminescent probe, Ru(II) complex-labeled oligonucleotides, which have a complementary sequence to the single-stranded regions of Escherichia coli 16S rRNA, were synthesized. After the hybridization of the probe to single-stranded regions of 16S rRNA, the segmental motions of the regions were evaluated by time-resolved luminescence anisotropy analysis. In 16S rRNA, the L2 site (323-332 nt) was found to be the most flexible among the seven sites chosen. From a comparison between the hybridization kinetics of oligonucleotides to these single-stranded regions and the rotational correlation times, it was suggested that the flexibility of the single-stranded region was closely correlated with the hybridization kinetics. Furthermore, results of the luminescence lifetime measurement and luminescence quenching experiments suggested that the highly flexible region was located on the surface of the 16S rRNA and that the less flexible region was located in the depths of 16S rRNA.     

Identification of aminotransferase genes for biosynthesis of aminoglycoside antibiotics from soil DNA

Aminoglycoside has been known as a clinically important antibiotic for a long time, but genetic information for the biosynthesis of aminoglycoside is still insufficient. In this study, we tried to clone aminoglycoside-biosynthetic genes from soil DNA for accumulation of genetic information. We chose the genes encoding L-glutamine:(2-deoxy-)scyllo-inosose aminotransferase as the target, because it is specific for all types of aminoglycoside biosynthesis. By degenerate PCR, we obtained 33 individual clones that were homologous with aminotransferase genes in aminoglycoside biosynthesis. Phylogenetic analysis and alignment of these genes showed that horizontal gene transfer has occurred in the soil. Among these, several quite interesting genes were obtained. Some genes probably originated from non-actinomycetes, and some were far from the known homologs. These genes can be useful markers for the isolation of entire gene clusters and originating organisms.