Inositol pyrophosphates regulate RNA polymerase I-mediated rRNA transcription in Saccharomyces cerevisiae.

Ribosome biogenesis is an essential cellular process regulated by the metabolic state of a cell. We examined whether inositol pyrophosphates, energy-rich derivatives of inositol that act as metabolic messengers, play a role in ribosome synthesis in the budding yeast, Saccharomyces cerevisiae. Yeast strains lacking the inositol hexakisphosphate (IP6) kinase Kcs1, which is required for the synthesis of inositol pyrophosphates, display increased sensitivity to translation inhibitors and decreased protein synthesis. These phenotypes are reversed on expression of enzymatically active Kcs1, but not on expression of the inactive form. The kcs1Δ yeast cells exhibit reduced levels of ribosome subunits, suggesting that they are defective in ribosome biogenesis. The rate of rRNA synthesis, the first step of ribosome biogenesis, is decreased in kcs1Δ yeast strains, suggesting that RNA polymerase I (Pol I) activity may be reduced in these cells. We determined that the Pol I subunits, A190, A43 and A34.5, can accept a ß-phosphate moiety from inositol pyrophosphates to undergo serine pyrophosphorylation. Although there is impaired rRNA synthesis in kcs1Δ yeast cells, we did not find any defect in recruitment of Pol I on rDNA, but observed that the rate of transcription elongation was compromised. Taken together, our findings highlight inositol pyrophosphates as novel regulators of rRNA transcription.

Inositol hexakisphosphate kinase 1 maintains hemostasis in mice by regulating platelet polyphosphate levels.

Polyphosphate (polyP), a polymer of orthophosphate moieties released from the dense granules of activated platelets, is a procoagulant agent. Inositol pyrophosphates, another group of phosphate-rich molecules, consist of mono- and diphosphates substituted on an inositol ring. Diphosphoinositol pentakisphosphate (IP7), the most abundant inositol pyrophosphate, is synthesized on phosphorylation of inositol hexakisphosphate (IP6) by IP6 kinases, of which there are 3 mammalian isoforms (IP6K1/2/3) and a single yeast isoform. Yeast lacking IP6 kinase are devoid of polyP, suggesting a role for IP6 kinase in maintaining polyP levels. We theorized that the molecular link between IP6 kinase and polyP is conserved in mammals and investigated whether polyP-dependent platelet function is altered in IP6K1 knockout (Ip6k1(-/-)) mice. We observe a significant reduction in platelet polyP levels in Ip6k1(-/-) mice, along with slower platelet aggregation and lengthened plasma clotting time. Incorporation of polyP into fibrin clots was reduced in Ip6k1(-/-) mice, thereby altering clot ultrastructure, which was rescued on the addition of exogenous polyP. In vivo assays revealed longer tail bleeding time and resistance to thromboembolism in Ip6k1(-/-) mice. Taken together, our data suggest a novel role for IP6K1 in regulation of mammalian hemostasis via its control of platelet polyP levels.

Indibacter alkaliphilus gen. nov., sp. nov., an alkaliphilic bacterium isolated from a haloalkaline lake.

A novel Gram-stain-negative, rod-shaped, non-motile bacterium, strain LW1(T), was isolated from a water sample collected at a depth of 3.5 m from Lonar Lake, Buldhana district, Maharashtra, India. The cell suspension was reddish-orange due to the presence of carotenoids. Strain LW1(T) was positive for catalase, oxidase, ornithine decarboxylase and lysine decarboxylase and negative for gelatinase, urease and lipase. Fatty acids were dominated by branched-chain fatty acids (>76 %), with a high abundance of iso-C(15 : 0) (48 %), anteiso-C(15 : 0) (7 %) and iso-C(17 : 0) 3-OH (11 %). Strain LW1(T) contained MK-4 and MK-7 as the major respiratory quinones and phosphatidylglycerol, phosphatidylcholine and phosphatidylethanolamine as the major phospholipids. A blast sequence similarity search based on 16S rRNA gene sequences indicated that members of the genera Belliella and Aquiflexum were the nearest phylogenetic neighbours with similarities of 91.8-92.3 %. Phylogenetic analyses indicated that strain LW1(T) formed a deep-rooted lineage distinct from the clades represented by the genera Belliella, Aquiflexum, Cyclobacterium, Echinicola and Algoriphagus. Based on the above-mentioned phenotypic and phylogenetic characteristics, it is proposed that strain LW1(T) represents a novel species in a new genus, Indibacter alkaliphilus gen. nov., sp. nov. (type strain LW1(T)=KCTC 22604(T)=CCUG 57479(T)). The genomic DNA G+C content of strain LW1(T) is 42.7+/-1 mol%.

Janibacter hoylei sp. nov., Bacillus isronensis sp. nov. and Bacillus aryabhattai sp. nov., isolated from cryotubes used for collecting air from the upper atmosphere.

Three novel bacterial strains, PVAS-1(T), B3W22(T) and B8W22(T), were isolated from cryotubes used to collect air samples at altitudes of between 27 and 41 km. Based on phenotypic characteristics, chemotaxonomic features, DNA-DNA hybridization with the nearest phylogenetic neighbours and phylogenetic analysis based on partial 16S rRNA gene sequences (PVAS-1(T), 1196 nt; B3W22(T), 1541 nt; B8W22(T), 1533 nt), the three strains were identified as representing novel species, and the names proposed are Janibacter hoylei sp. nov. (type strain PVAS-1(T) =MTCC 8307(T) =DSM 21601(T) =CCUG 56714(T)), Bacillus isronensis sp. nov. (type strain B3W22(T) =MTCC 7902(T) =JCM 13838(T)) and Bacillus aryabhattai sp. nov. (type strain B8W22(T) =MTCC 7755(T) =JCM 13839(T)).

Bhargavaea cecembensis gen. nov., sp. nov., isolated from the Chagos-Laccadive ridge system in the Indian Ocean.

A novel Gram-positive, rod-shaped, non-motile, non-spore-forming bacterium, strain DSE10(T), was isolated from a deep-sea sediment sample collected at a depth of 5904 m from the Chagos-Laccadive ridge system in the Indian Ocean. Cells of strain DSE10(T) were positive for catalase, oxidase, urease and lipase activities and contained iso-C(14 : 0), iso-C(15 : 0), iso-C(16 : 0) and anteiso-C(15 : 0) as the major fatty acids. The major respiratory quinones were MK-6 and MK-8 and the major lipids were phosphatidylglycerol and diphosphatidylglycerol. The cell-wall peptidoglycan contained diaminopimelic acid as the diagnostic diamino acid. A blast sequence similarity search based on 16S rRNA gene sequences indicated that the genera Planococcus, Planomicrobium, Bacillus and Geobacillus were the nearest phylogenetic neighbours to the novel isolate with gene sequence similarities ranging from 94.9 to 95.2 %. Phylogenetic analyses using neighbour-joining, minimum-evolution and maximum-parsimony methods indicated that strain DSE10(T) formed a deeply rooted lineage distinct from the clades represented by the genera Planococcus, Planomicrobium, Bacillus and Geobacillus. Further, strain DSE10(T) could be distinguished from the above-mentioned genera based on the presence of signature nucleotides G, A, C, T, C, A, G, C and T at positions 182, 444, 480, 492, 563, 931, 1253, 1300 and 1391, respectively, in the 16S rRNA gene sequence. Based on the phenotypic and phylogenetic characteristics determined in this study, strain DSE10(T) was assigned as the type species of a new genus, Bhargavaea gen. nov., as Bhargavaea cecembensis sp. nov. The type strain of Bhargavaea cecembensis gen. nov., sp. nov. is DSE10(T) (=LMG 24411(T)=JCM 14375(T)). The genomic DNA G+C content of strain DSE10(T) is 59.5+/-2.5 mol%.

Exiguobacterium soli sp. nov., a psychrophilic bacterium from the McMurdo Dry Valleys, Antarctica.

A novel psychrophilic bacterium, designated strain DVS 3Y(T), was isolated from a moraine sample from the McMurdo Dry Valleys, Antarctica. Phenotypic and chemotaxonomic characteristics and data from a phylogenetic analysis based on 16S rRNA gene sequences indicated that strain DVS 3Y(T) was related to the genus Exiguobacterium. Strain DVS 3Y(T) exhibited >97 % gene sequence similarity with respect to Exiguobacterium acetylicum DSM 20416(T) (97.4 %), Exiguobacterium oxidotolerans DSM 17272(T) (97.4 %), Exiguobacterium indicum IAM 15368(T) (97.6 %), Exiguobacterium undae DSM 14481(T) (98.2 %), Exiguobacterium sibiricum DSM 17290(T) (98.6 %) and Exiguobacterium antarcticum DSM 14480(T) (99.6 %). However, the levels of DNA-DNA relatedness between strain DVS 3Y(T) and E. acetylicum DSM 20416(T), E. oxidotolerans JCM 12280(T), E. indicum IAM 15368(T), E. undae DSM 14481(T), E. sibiricum DSM 17290(T) and E. antarcticum DSM 14480(T) were less than 70 % (52, 25, 16, 33, 16 and 38 %, respectively). Strain DVS 3Y(T) also differed from these six closely related species in a number of phenotypic traits. Phenotypic, chemotaxonomic and phylogenetic data suggest that strain DVS 3Y(T) represents a novel species of the genus Exiguobacterium, for which the name Exiguobacterium soli sp. nov. is proposed. The type strain is DVS 3Y(T) (=MTCC 4816(T)=JCM 14376(T)).

Lipid profile of rats fed blends of rice bran oil in combination with sunflower and safflower oil.

This study was undertaken to assess the effect of blended oils, i.e., polyunsaturated fatty acid (PUFA) rich vegetable oils like safflower oil (SFO) and sunflower oil (SNO) with the unconventional and hypocholesterolemic rice bran oil (RBO) on the serum lipid profile of rats. Rats fed RBO+SNO/SFO at 70:30 ratio for a period of 28 days showed significantly (p < 0.05) lower levels of total cholesterol (TC), triglycerides (TG) and low density lipoprotein (LDL) cholesterol and increased high density lipoprotein (HDL) cholesterol in animals fed a high cholesterol diet (HCD) and cholesterol free diet (CFD). Liver total cholesterol (TC) and triglycerides (TG) were also reduced. Fecal excretion of neutral sterols and bile acids was increased with use of RBO blends. RBO, which is rich in tocopherols and tocotrienols, may improve the oxidative stability of the blends. Tocotrienols are known to inhibit 3-hydroxy, 3-methyl, glutaryl CoA (HMG-COA) reductase (rate limiting enzyme in cholesterol biosynthesis), resulting in hypocholesterolemia. In addition to improving the lipid profile by lowering TC, TG and LDL-C and increasing HDL-C, blending of RBO with other oils can result in an economic advantage of lower prices.

Red palm oil for combating vitamin A deficiency.

Red palm oil (Elaeis guineensis,RPO) is nutritionally rich and unique in comparison with other edible oils as it has a high content of b-carotene (400 ppm).It is the ideal choice for combating vitamin A deficiency in developing countries. The Modified Relative Dose Response test was conducted to assess the vitamin A status of school children fed RPO in the form of a sweet snack supplying the RDA (2400 µg) of b-carotene for two months. A significant increase was seen in serum retinol levels from 0.86 ± 0.14 to 1.89 ± 0.23 µmol/L, comparable with a control group fed oral vitamin A drops daily whose retinol levels increased from 0.74 ± 0.09 to 1.94 ± 0.21µmol/L. The dehydroretinol/ retinol ratio (DR/R) decreased from 0.073 ± 0.025 to 0.023 ± 0.003 in a RPO group and from 0.095 ± 0.023 to 0.023 ± 0.004 in the vitamin A group, indicating saturation of liver reserves of retinol, the cut-off point for inadequate status being > 0.03. In another study, school children fed RPO snacks for one month were compared with massive vitamin A dosed groups. Serum retinol level increased significantly in both groups. Serum b-carotene increased from 0.06 ± 0.002 to 0.21 ± 0.01 µmol/L in the RPO group, but remained the same in a control group. A third study indicated that RPO can afford protection for as long as six months, similar to massive vitamin A doses. School children fed RPO snack for one month as per the RDA, maintained normal levels even after six months of cessation of supplementation. Children fed 50 % of RDA from RPO snack also maintained normal levels (>0.7µ mol/L) at the end of six months of supplementation. Hence, periodic bouts of RPO feeding twice or thrice a year may help in maintaining adequate vitamin A status throughout the year. Hence RPO has great promise in maintaining the nutritional well-being of the population.

The protective effect of red palm oil in comparison with massive vitamin A dose in combating vitamin A deficiency in Orissa, India.

Vitamin A deficiency has long been a serious hazard to the world community, especially to children. The main reason for a higher incidence among children is lack of vitamin A in the diet. Carotene rich supplements with sources like Red Palm oil (RPO) could be used as a measure to combat vitamin A deficiency. This study evaluates the protective effect of RPO in comparison with massive vitamin A dose to combat vitamin A deficiency. The study was carried out for a period of three months in 36 school children. Twelve children received a massive dose (50,000 IU) of vitamin A, another twelve children received 4g of RPO containing B-carotene equivalent to 25,000 IU of vitamin A in "Besan laddu" and the remaining twelve received 8g of RPO containing B-carotene equivalent to 50,000 IU of vitamin A in "Besan laddu". Serum vitamin A levels were estimated initially, after 15 days of supplementation and 3 months after termination of supplementation. The levels were maximum 15 days after the supplementation and, though it fell by the end of 3 months, yet it was significantly higher than that of the initial levels in all the three groups. Among both the levels of RPO supplement, 8g RPO was as efficient as was a massive vitamin A dose in providing protection for three months, after cessation of supplementation.

Red palm oil as a source of beta-carotene for combating vitamin A deficiency.

Twenty four school children of 7-9 years of age were divided into two groups of six boys and six girls each. One group was given a daily supplement of 'Suji halwa', a sweet snack made with semolina and red palm oil, supplying 2400 mu g of beta-carotene and the second group was the control group which was given 600 mu g of oral vitamin A palmitate, for 60 days. Vitamin A status before and after supplementation was assessed by the Modified Relative Dose Response Assay (MRDR). Results indicated that serum vitamin A levels increased from the basal level of 0.86 +/- 0.13 mu m mol/l to 1.891 +/- 0.23 mu mol/l in the Red Palmoil (RPO) group and from 0.74 +/- 0.09 to 1.94 +/- 0.21 mu mol/l in the control vitamin A group. Dehydroretinol/Retinol (DR/R) ratio decreased from 0.073 +/- 0.025 to 0.023 +/- 0.004 in the RPO group and from 0.090 +/- 0.023 to 0.023 +/- 0.004 in the vitamin A group, indicating liver saturation with vitamin A after feeding RPO snacks, comparable to synthetic vitamin A. This study indicates that RPO is an efficient source of beta-carotene which is found to be bioavailable in all the subjects tested, hence it can be used for supplementary feeding programmes to combat vitamin A deficiency in target population.

Effect of red palm oil on some hepatic drug-metabolizing enzymes in rats.

Red palm oil (RPO) from Elaeis guineensis is being considered for use as an edible oil in India as it is one of the richest natural sources of carotenoids. The effect of RPO on the host detoxification system, which is a vital mechanism in cancer prevention, was studied in three separate batches of Wistar/NIN inbred albino rats, and compared with controls, groundnut oil (GNO) and refined bleached deodorized palmolein oil (RBDPO). The first batch of 36 rats (12 from each group) comprised the adult males (26 wk old) of the third generation (F2b) from a multigeneration reproduction study in which three groups were fed 10% GNO or RPO or RBDPO for three generations continuously. Phase II glutathione-S-transferase (GSH-T) activity was measured in the liver cytosol of these rats after they had twice completed the process of mating, gestation, lactation and weaning, because GSH-T is one of the principal detoxifying enzymes involved in conjugating reactions of phase II metabolism. The fourth generation (F3b) weanling rats of the three groups, receiving GNO, RPO or RBDPO, were continued on the 10% oil diet for 9 wk, after which cytosolic GSH-T activity was measured. In the second experiment, eight male weanling Wistar/NIN inbred albino rats, 5 wk old, weighing 100-120 g, were fed 10% GNO, RPO or RBDPO for 4 wk in a 20% protein synthetic diet. Liver cytosolic GSH-T, reduced glutathione, microsomal total cytochrome P-450, aminopyrine N-demethylase and ethoxyresorufin-O-deethylase activity were measured to elucidate the effect of RPO on some phase I and phase II reactions. Significantly higher levels of GSH-T were observed in F2b and F3b rats given RPO than in those given GNO or RBDPO. In the second experiment, GSH-T induction was also noted, together with increased levels of reduced GSH. Phase I enzymes and total cytochrome P-450 levels were comparable between groups, indicating that no induction attributable to RPO had occurred. Thus, enhancement of one of the detoxifying phase II enzymes, in conjunction with the lack of induction of those activating phase I enzymes that are known to metabolize phenobarbitone and polycyclic aromatic hydrocarbons, suggests that RPO affords protection against chemical carcinogens, probably because of its carotenoid content.

Multigeneration studies on red palm oil, and on hydrogenated vegetable oil containing mahua oil.

Edible grade red palm oil (RPO; Elaeis guineensis) is being considered for use an an edible oil in India since it is one of the richest natural sources of carotenoids. Earlier chemical and nutritional evaluations in rats indicated no adverse effects. Multigeneration breeding studies in rats have now been carried out. Mahua oil (MO; Madhuca latifolia) is used in hydrogenated vegetable oil (HVO) for human consumption. Earlier studies on MO indicated adverse effects on the male reproductive system. Hence, a study was undertaken to evaluate the safety of HVO containing 30% MO (MO-HVO) in terms of reproductive performance. A three-generation study was conducted with groups of 12 male and 12 female Wistar/NIN/inbred albino rats fed, at 10% in the diet (20% protein), groundnut oil (controls), RPO, refined, bleached and deodorized palmolein (RBDPO), or MO-HVO. Reproductive parameters including percentage conception, birth weight, litter size, weanling weight, sex ratio at birth and weaning, preweaning mortality and number of days from introduction to mating, were recorded. Behavioural and reflexological tests were conducted on preweaning animals. Adult animals were subjected to weekly observation. No significant differences were found between the RPO and MO-HVO groups in comparison with groups fed GNO or RBDPO in any of the above parameters. However, certain indications of reduced fertility were observed in the MO-HVO group in the first and third generations. The results indicate that RPO did not produce any adverse effect on reproductive performance or other toxicological parameters studied, and therefore it can be considered as safe for consumption. On the other hand, HVO containing 30% MO needs further testing with a larger number of animals.

Nutritional evaluation of crude palm oil in rats.

Edible-grade crude palm oil (CPO: from Elaeis guineensis) is one of the richest natural sources of beta-carotene (7500 mumol/L) and is cheaper than other edible oils, making it a promising source of vitamin A in a deficient population. Nutritional studies were conducted on weanling albino rats of the Wistar/NIN strain for 28 and 90 d. Diets contained 10% of either CPO, groundnut oil (GNO), or refined palm-olein oil (RPO) and adequate amounts of all other nutrients. No adverse effects were observed as judged by growth rate, feed-efficiency ratio, protein-efficiency ratio, net protein utilization, digestibility, fat absorption, nitrogen balance, phosphorus and calcium retention, serum enzymes, and blood hematology, which were comparable with control values. Lipid profiles of the animals of the 28-d study indicated that CPO and RPO had higher amounts of cholesterol and triglycerides than did GNO although tissue lipids were comparable. In the 90-d study, however, lipid concentrations were comparable with control values. These results suggest that CPO has adequate nutritional quality compared with GNO and RPO.