Reduced hepatic AdipoR2 by increased glucocorticoid mediates effect of psychosocial stress to elevate serum cholesterol.

Understanding the effects of psychosocial stress on serum cholesterol may offer valuable insights into the relationship between psychological disorders and endocrine diseases. However, these effects and their underlying mechanisms have not been elucidated yet. Here we show that serum corticosterone, total cholesterol and low-density lipoprotein cholesterol (LDL-C) are elevated in a mouse model of psychosocial stress. Furthermore, alterations occur in AdipoR2-mediated AMPK and PPARα signaling pathways in liver, accompanied by a decrease in LDL-C clearance and an increase in cholesterol synthesis. These changes are further verified in wild-type and AdipoR2 overexpression HepG2 cells incubated with cortisol and AdipoR agonist, and are finally confirmed by treating wild-type and hepatic-specific AdipoR2 overexpression mice with corticosterone. We conclude that increased glucocorticoid mediates the effects of psychosocial stress to elevate serum cholesterol by inhibiting AdipoR2-mediated AMPK and PPARα signaling to decrease LDL-C clearance and increase cholesterol synthesis in liver.

Hypothetical chloroplast reading frame 51 encodes a photosystem I assembly factor in cyanobacteria.

Hypothetical chloroplast open reading frames (ycfs) are putative genes in the plastid genomes of photosynthetic eukaryotes. Many ycfs are also conserved in the genomes of cyanobacteria, the presumptive ancestors of present-day chloroplasts. The functions of many ycfs are still unknown. Here, we generated knock-out mutants for ycf51 (sll1702) in the cyanobacterium Synechocystis sp. PCC 6803. The mutants showed reduced photoautotrophic growth due to impaired electron transport between photosystem II (PSII) and PSI. This phenotype results from greatly reduced PSI content in the ycf51 mutant. The ycf51 disruption had little effect on the transcription of genes encoding photosynthetic complex components and the stabilization of the PSI complex. In vitro and in vivo analyses demonstrated that Ycf51 cooperates with PSI assembly factor Ycf3 to mediate PSI assembly. Furthermore, Ycf51 interacts with the PSI subunit PsaC. Together with its specific localization in the thylakoid membrane and the stromal exposure of its hydrophilic region, our data suggest that Ycf51 is involved in PSI complex assembly. Ycf51 is conserved in all sequenced cyanobacteria, including the earliest branching cyanobacteria of the Gloeobacter genus, and is also present in the plastid genomes of glaucophytes. However, Ycf51 has been lost from other photosynthetic eukaryotic lineages. Thus, Ycf51 is a PSI assembly factor that has been functionally replaced during the evolution of oxygenic photosynthetic eukaryotes.

Kovacikia minuta sp. nov. (Leptolyngbyaceae, Cyanobacteria), a new freshwater chlorophyll f-producing cyanobacterium.

A few groups of cyanobacteria have been characterized as having far-red light photoacclimation (FaRLiP) that results from chlorophyll f (Chl f) production. In this study, using a polyphasic approach, we taxonomically transferred the Cf. Leptolyngbya sp. CCNUW1 isolated from a shaded freshwater pond, which produces Chl f under far-red light, to the genus Kovacikia and named this taxon Kovacikia minuta sp. nov. This strain was morphologically similar to Leptolyngbya-like strains. The thin filaments were purplish-brown under white light but became grass green under far-red light. The 31-gene phylogeny grouped K. minuta CCNU0001 into order Synechococcales and family Leptolyngbyaceae. Phylogenetic analysis based on 16S rRNA gene sequences further showed that K. minuta CCNU0001 was clustered into Kovacikia with similarities of 97.2-97.4% to the recently reported type species of Kovacikia muscicola HA7619-LM3. Additionally, the internal transcribed spacer region between 16S-23S rRNA genes had a unique sequence and secondary structure compared with other Kovacikia strains and phylogenetically related taxa. Draft genome sequences of K. minuta CCNU0001 (8,564,336 bp) were assembled into one circular chromosome and two circular plasmids. A FaRLiP 20-gene cluster comprised two operons with the unique organization. In sum, K. minuta was established as a new species, and it is the first species reported to produce Chl f and for which a draft genome was produced in genus Kovacikia. This study expanded our knowledge regarding the diversity of Chl f-producing cyanobacteria in far-red light-enriched environments and provides important foundational information for future investigations of FaRLiP evolution in cyanobacteria.

A unique porin meditates iron-selective transport through cyanobacterial outer membranes.

Cyanobacteria are globally important primary producers and nitrogen fixers with high iron demands. Low ambient dissolved iron concentrations in many aquatic environments mean that these organisms must maintain sufficient and selective transport of iron into the cell. However, the nature of iron transport pathways through the cyanobacterial outer membrane remains obscure. Here we present multiple lines of experimental evidence that collectively support the existence of a novel class of substrate-selective iron porin, Slr1908, in the outer membrane of the cyanobacterium Synechocystis sp. PCC 6803. Elemental composition analysis and short-term iron uptake assays with mutants in Slr1908 reveal that this protein is primarily involved in inorganic iron uptake and contributes less to the accumulation of other metals. Homologues of Slr1908 are widely distributed in both freshwater and marine cyanobacteria, most notably in unicellular marine diazotrophs. Complementary experiments with a homologue of Slr1908 in Synechococcus sp. PCC 7002 restored the phenotype of Synechocystis knockdown mutants, showing that this siderophore producing species also possesses a porin with a similar function in Fe transport. The involvement of a substrate-selective porins in iron uptake may allow cyanobacteria to tightly control iron flux into the cell, particularly in environments where iron concentrations fluctuate.

Photosynthetic adaptation to light availability shapes the ecological success of bloom-forming cyanobacterium Pseudanabaena to iron limitation.

The poorly understood filamentous cyanobacterium Pseudanabaena is commonly epiphytic on Microcystis colonies and their abundances are often highly correlated during blooms. The response and adaptation of Microcystis to iron limitation have been extensively studied, but the strategies Pseudanabaena uses to respond to iron limitation are largely unknown. Here, physiological responses to iron limitation were compared between one Pseudanabaena and two Microcystis strains grown under different light intensities. The results showed that low-intensity light exacerbated, but high-intensity light alleviated, the negative effect of iron limitation on Pseudanabaena growth relative to two Microcystis strains. It was found that robust light-harvesting and photosynthetic efficiency allowed adaptation of Pseudanabaena to low light availability relative to two Microcystis strains only during iron sufficiency. The results also indicated that a larger investment in the photosynthetic antenna probably contributed to light/iron co-limitation of Pseudanabaena relative to two Microcystis strains under both light and iron limitation. Furthermore, the lower antenna pigments/chlorophyll a ratio and photosynthetic efficiency, and higher nonphotochemical quenching and saturation irradiance provided Pseudanabaena photoadaptation and photoprotection advantages over the two Microcystis strains under the high-light condition. The lower investment in antenna pigments of Pseudanabaena than the two Microcystis strains under high-light intensity is likely an efficient strategy for both saving iron quotas and decreasing photosensitivity. Therefore, when compared with Microcystis, the high plasticity of antenna pigments, along with the excellent photoadaptation and photoprotection ability of Pseudanabaena, probably ensures its ecological success under iron limitation when light is sufficient.

Widespread occurrence and unexpected diversity of red-shifted chlorophyll producing cyanobacteria in humid subtropical forest ecosystems.

Discovery of red-shifted chlorophyll d and f in cyanobacteria has opened up new avenues to estimate global carbon fixation driven by far-red light. Shaded habitats in humid subtropical forest ecosystems contain an increased proportion of far-red light components relative to residual white light. After an extensive survey of shaded ecosystems within subtropical forests, wide occurrence of red-shifted chlorophyll-producing cyanobacteria was demonstrated by isolated Chl f-producing and Chl d-containing cyanobacteria. Chl f-producing cyanobacteria were classified into the genera of Aphanocapsa and Chroococcidiopsis and two undescribed genera within Leptolyngbyaceae. Newly isolated Chl d-containing Acaryochloris sp. CCNUM4 showed the closest phylogenetic relationship with Acaryochloris species isolated from marine environments. Acaryochloris sp. CCNUM4 produced Chl d as major photopigment, and Chl f-producing cyanobacteria use Chl a under white light conditions but Chl a + f under far-red light conditions. Their habitats are widely distributed in subtropical forest ecosystems and varied from mosses on limestone to macrophyte and freshwater in the streams and ponds. This study presents a significant advance in the knowledge of distribution and diversity of red-shifted chlorophyll-producing cyanobacteria in terrestrial ecosystems. The results suggest that Chl f-producing and Chl d-containing cyanobacteria might be important primary producers in far-red light dominant niches worldwide.

Orange and red carotenoid proteins are involved in the adaptation of the terrestrial cyanobacterium Nostoc flagelliforme to desiccation.

The remarkable drought-resistance of the terrestrial cyanobacterium Nostoc flagelliforme (N. flagelliforme) has attracted attention for many years. In this study, we purified a group of red proteins that accumulate in dried field samples of N. flagelliforme. These red proteins contain canthaxanthin as the bound chromophore. Native-PAGE analysis revealed that the purified red proteins resolved into six visible red bands and were composed of four helical carotenoid proteins (HCPs), HCP1, HCP2, HCP3, and HCP6 (homologs to the N-terminal domain of the orange carotenoid protein (OCP)). Seven genes encode homologs of the OCP in the genome of N. flagelliforme: two full-length ocp genes (ocpx1 and ocpx2), four N-terminal domain hcp genes (hcp1, hcp2, hcp3, and hcp6), and one C-terminal domain ccp gene. The expression levels of hcp1, hcp2, and hcp6 were highly dependent on the water status of field N. flagelliforme samples, being downregulated during rehydration and upregulated during subsequent dehydration. Transcripts of ocpx2 were dominant in the dried field samples, which we confirmed by detecting the presence of OCPx2-derived peptides in the purified red proteins. The results shed light on the relationship between carotenoid-binding proteins and the desiccation resistance of terrestrial cyanobacteria, and the physiological functions of carotenoid-binding protein complexes in relation to desiccation are discussed.

Outer Membrane Iron Uptake Pathways in the Model Cyanobacterium Synechocystis sp. Strain PCC 6803.

Cyanobacteria are foundational drivers of global nutrient cycling, with high intracellular iron (Fe) requirements. Fe is found at extremely low concentrations in aquatic systems, however, and the ways in which cyanobacteria take up Fe are largely unknown, especially the initial step in Fe transport across the outer membrane. Here, we identified one TonB protein and four TonB-dependent transporters (TBDTs) of the energy-requiring Fe acquisition system and six porins of the passive diffusion Fe uptake system in the model cyanobacterium Synechocystis sp. strain PCC 6803. The results experimentally demonstrated that TBDTs not only participated in organic ferri-siderophore uptake but also in inorganic free Fe (Fe') acquisition. 55Fe uptake rate measurements showed that a TBDT quadruple mutant acquired Fe at a lower rate than the wild type and lost nearly all ability to take up ferri-siderophores, indicating that TBDTs are critical for siderophore uptake. However, the mutant retained the ability to take up Fe' at 42% of the wild-type Fe' uptake rate, suggesting additional pathways of Fe' acquisition besides TBDTs, likely by porins. Mutations in four of the six porin-encoding genes produced a low-Fe-sensitive phenotype, while a mutation in all six genes was lethal to cell survival. These diverse outer membrane Fe uptake pathways reflect cyanobacterial evolution and adaptation under a range of Fe regimes across aquatic systems.IMPORTANCE Cyanobacteria are globally important primary producers and contribute about 25% of global CO2 fixation. Low Fe bioavailability in surface waters is thought to limit the primary productivity in as much as 40% of the global ocean. The Fe acquisition strategies that cyanobacteria have evolved to overcome Fe deficiency remain poorly characterized. We experimentally characterized the key players and the cooperative work mode of two Fe uptake pathways, including an active uptake pathway and a passive diffusion pathway in the model cyanobacterium Synechocystis sp. PCC 6803. Our finding proved that cyanobacteria use ferri-siderophore transporters to take up Fe', and they shed light on the adaptive mechanisms of cyanobacteria to cope with widespread Fe deficiency across aquatic environments.

Sycrp2 Is Essential for Twitching Motility in the Cyanobacterium Synechocystis sp. Strain PCC 6803.

Two cAMP receptor proteins (CRPs), Sycrp1 (encoded by sll1371) and Sycrp2 (encoded by sll1924), exist in the cyanobacterium Synechocystis sp. strain PCC 6803. Previous studies have demonstrated that Sycrp1 has binding affinity for cAMP and is involved in motility by regulating the formation of pili. However, the function of Sycrp2 remains unknown. Here, we report that sycrp2 disruption results in the loss of motility of Synechocystis sp. PCC 6803, and that the phenotype can be recovered by reintroducing the sycrp2 gene into the genome of sycrp2-disrupted mutants. Electron microscopy showed that the sycrp2-disrupted mutant lost the pilus apparatus on the cell surface, resulting in a lack of cell motility. Furthermore, the transcript level of the pilA9-pilA11 operon (essential for cell motility and regulated by the cAMP receptor protein Sycrp1) was markedly decreased in sycrp2-disrupted mutants compared with the wild-type strain. Moreover, yeast two-hybrid analysis and a pulldown assay demonstrated that Sycrp2 interacted with Sycrp1 to form a heterodimer and that Sycrp1 and Sycrp2 interacted with themselves to form homodimers. Gel mobility shift assays revealed that Sycrp1 specifically binds to the upstream region of pilA9 Together, these findings indicate that in Synechocystis sp. PCC 6803, Sycrp2 regulates the formation of pili and cell motility by interacting with Sycrp1.IMPORTANCE cAMP receptor proteins (CRPs) are widely distributed in cyanobacteria and play important roles in regulating gene expression. Although many cyanobacterial species have two cAMP receptor-like proteins, the functional links between them are unknown. Here, we found that Sycrp2 in the cyanobacterium Synechocystis sp. strain PCC 6803 is essential for twitching motility and that it interacts with Sycrp1, a known cAMP receptor protein involved with twitching motility. Our findings indicate that the two cAMP receptor-like proteins in cyanobacteria do not have functional redundancy but rather work together.

The identification of IsiA proteins binding chlorophyll d in the cyanobacterium Acaryochloris marina.

The bioavailable iron in many aquatic ecosystems is extremely low, and limits the growth and photosynthetic activity of phytoplankton. In response to iron limitation, a group of chlorophyll-binding proteins known as iron stress-induced proteins are induced and serve as accessory light-harvesting components for photosystems under iron limitation. In the present study, we investigated physiological features of Acaryochloris marina in response to iron-deficient conditions. The growth doubling time under iron-deficient conditions was prolonged to ~3.4 days compared with 1.9 days under normal culture conditions, accompanied with dramatically decreased chlorophyll content. The isolation of chlorophyll-binding protein complexes using sucrose density gradient centrifugation shows six main green bands and three main fluorescence components of 712, 728, and 748 nm from the iron-deficient culture. The fluorescence components of 712 and 728 nm co-exist in the samples collected from iron-deficient and iron-replete cultures and are attributed to Chl d-binding accessory chlorophyll-binding antenna proteins and also from photosystem II. A new chlorophyll-binding protein complex with its main fluorescence peak at 748 nm was observed and enriched in the heaviest fraction from the samples collected from the iron-deficient culture only. Combining western blotting analysis using antibodies of CP47 (PSII), PsaC (PSI) and IsiA and proteomic analysis on an excised protein band at ~37 kDa, the heaviest fraction (-F6) isolated from iron-deficient culture contained Chl d-bound PSI-IsiA supercomplexes. The PSII-antenna supercomplexes isolated from iron-replete conditions showed two fluorescence peaks of 712 and 728 nm, which can be assigned as 6-transmembrane helix chlorophyll-binding antenna and photosystem II fluorescence, respectively, which is supported by protein analysis of the fractions (F5 and F6).

Different physiological responses of cyanobacteria to ultraviolet-B radiation under iron-replete and iron-deficient conditions: Implications for underestimating the negative effects of UV-B radiation.

Iron deficiency has been considered one of the main limiting factors of phytoplankton productivity in some aquatic systems including oceans and lakes. Concomitantly, solar ultraviolet-B radiation has been shown to have both deleterious and positive impacts on phytoplankton productivity. However, how iron-deficient cyanobacteria respond to UV-B radiation has been largely overlooked in aquatic systems. In this study, physiological responses of four cyanobacterial strains (Microcystis and Synechococcus), which are widely distributed in freshwater or marine systems, were investigated under different UV-B irradiances and iron conditions. The growth, photosynthetic pigment composition, photosynthetic activity, and nonphotochemical quenching of the different cyanobacterial strains were drastically altered by enhanced UV-B radiation under iron-deficient conditions, but were less affected under iron-replete conditions. Intracellular reactive oxygen species (ROS) and iron content increased and decreased, respectively, with increased UV-B radiation under iron-deficient conditions for both Microcystis aeruginosa FACHB 912 and Synechococcus sp. WH8102. On the contrary, intracellular ROS and iron content of these two strains remained constant and increased, respectively, with increased UV-B radiation under iron-replete conditions. These results indicate that iron-deficient cyanobacteria are more susceptible to enhanced UV-B radiation. Therefore, UV-B radiation probably plays an important role in influencing primary productivity in iron-deficient aquatic systems, suggesting that its effects on the phytoplankton productivity may be underestimated in iron-deficient regions around the world.

Identification of an iron permease, cFTR1, in cyanobacteria involved in the iron reduction/re-oxidation uptake pathway.

Cyanobacteria are globally important primary producers and abundant in many iron-limited aquatic environments. The ways in which they take up iron are largely unknown, but reduction of Fe3+ is an important step in the process. Here we report a special iron permease in Synechocystis, cFTR1, that is required for Fe3+ uptake following Fe2+ re-oxidation. The expression of cFTR1 is induced by iron starvation, and a mutant lacking the gene is abnormally sensitive to iron starvation. The cFTR1 protein localizes to the plasma membrane and contains the iron-binding motif "REXXE". Point-directed mutagenesis of the REXXE motif results in a sensitivity to Fe-deficiency. Measurements of iron (55 Fe) uptake rate show that cFTR1 takes up Fe3+ rather than Fe2+ . The function of cFTR1 in Synechocystis could be genetically complemented by the iron permease, Ftr1p, of Saccharomyces cerevisiae, that is known to transport Fe3+ produced by the oxidation of Fe2+ via a multicopper oxidase. Unlike yeast Ftr1p, cyanobacterial cFTR1 probably obtains Fe3+ primarily from the oxidation of Fe2+ by oxygen. Growth assays show that the cFTR1 is required during oxygenic, photoautotrophic growth but not when oxygen production is inhibited during photoheterotrophic growth. In cyanobacteria, iron reduction/re-oxidation uptake pathway may represent their adaptation to oxygenated environments.

Capsular polysaccharides facilitate enhanced iron acquisition by the colonial cyanobacterium Microcystis sp. isolated from a freshwater lake.

Microcystis sp., especially in its colonial form, is a common dominant species during cyanobacterial blooms in many iron-deficient water bodies. It is still not entirely clear, however, how the colonial forms of Microcystis acclimate to iron-deficient habitats, and the responses of unicellular and colonial forms to iron-replete and iron-deficient conditions were examined here. Growth rates and levels of photosynthetic pigments declined to a greater extent in cultures of unicellular Microcystis than in cultures of the colonial form in response to decreasing iron concentrations, resulting in the impaired photosynthetic performance of unicellular Microcystis as compared to colonial forms as measured by variable fluorescence and photosynthetic oxygen evolution. These results indicate that the light-harvesting ability and photosynthetic capacity of colonial Microcystis was less affected by iron deficiency than the unicellular form. The carotenoid contents and nonphotochemical quenching of colonial Microcystis were less reduced than those of the unicellular form under decreasing iron concentrations, indicating that the colonial morphology enhanced photoprotection and acclimation to iron-deficient conditions. Furthermore, large amounts of iron were detected in the capsular polysaccharides (CPS) of the colonies, and more iron was found to be attached to the colonial Microcystis CPS under decreasing iron conditions as compared to unicellular cultures. These results demonstrated that colonial Microcystis can acclimate to iron deficiencies better than the unicellular form, and that CPS plays an important role in their acclimation advantage in iron-deficient waters.

Association of Leptin Receptor Gene Polymorphisms with Genetic Susceptibility to Ischemic Stroke.

BACKGROUND: Ischemic stroke is a multifactorial disease that is influenced by both genetic and environmental factors. Identification of the genetic factors that are underlining this disease is important. Leptin receptor (LEPR) mediates the leptin-regulated human energy homeostasis, and mutations of LEPR can increase cardiovascular risks and may predispose an individual to ischemic stroke. METHODS: We analyzed distribution of 3 single nucleotide polymorphisms (SNPs) of LEPR gene (Lys109Arg, Gln223Arg, and Lys656Asn) in 101 patients with ischemic stroke and 105 controls by polymerase chain reaction-restriction fragment length polymorphism strategy. RESULTS: Our results showed that there were significant differences in the genotype and allele distribution of Lys109Arg and Gln223Arg polymorphisms of the LEPR gene between case and control. The 109GG and 223GG genotype were associated with a significantly increased risk of ischemic stroke (odds ratio [OR], 3.23; P = .001 and OR, 2.87; P = .008, respectively). The 109G and 223G alleles carriers were correlated with an increased incidence of ischemic stroke (OR, 2.72; P = .001; OR, 2.94; P = .004). By haplotype analyses, we found that 109A/223G/656G haplotype was associated with an increased risk of ischemic stroke although this was not observed in the control group (OR, 3.86; P = .029). CONCLUSIONS: LEPR 109GG and 223GG genotypes and the 109G and 223G alleles are associated with the risk of ischemic stroke. Our data suggest that LEPR Lys109Arg and Gln223Arg polymorphisms could be used as genetic predictive factor for ischemic stroke.

[The association study of the LIPC -250g/A polymorphism and high-carbohydrate/low-fat diet induced serum lipid and apolipoprotein concentration changes in healthy youth].

OBJECTIVE: To investigate the role of the - 250G/A polymorphism in the promoter region of hepatic lipase gene (LIPC) on serum lipid profile and its interactions with a high-carbohydrate/low-fat (HC/LF) diet on serum lipid profiles in a young healthy Chinese population. METHODS: After a stabilization diet for seven days, fifty-six young healthy subjects (27 males, 29 females) were given the HC/LF diet for six days. The serum lipid profiles were analyzed of the twelve-hour fasting venous blood samples collected in the mornings of the first, the eighth and the fourteenth days. The concentrations of serum apolipoproteins were measured. The LIPC -250G/A polymorphism were analyzed. RESULTS: At baseline, the female subjects with the GG genotype had significantly higher high-density lipoprotein cholesterol (HDL-C) (P= 0. 041) and apolipoprotein A- I (Apo A- I ) (P= 0. 020) than the male subjects with the same genotype. After the stabilization diet, the females had significantly higher HDL-C (GG genotype: P=0. 021, A carriers: P=0. 014) and Apo A-I (GG genotype: P= 0. 035, A carriers: P= 0. 006) than the males in all genotypes. After the HC/LF diet, the female A carriers had significantly higher total cholesterol (TC) (P= 0. 042) than the male A carriers, and the females had significantly higher Apo A- I than the males in all genotypes (GG genotype: P=0. 010, A carriers: P=0. 009). Compared with thosebefore the HC / LF diet , TC ( males with GG genotype : P = 0. 013 , male A carriers: P = 0. 000 ; females with GG genotype: P=0. 025, female A carriers: P=0. 048) and low-density lipoprotein cholesterol (LDL-C) (males with GG genotype: P = 0. 028, male A carriers: P = 0. 000; females with GG genotype: P= 0. 004, female A carriers: P=0. 001) significantly decreased after the diet in all the subjects. Triglycerides (TAG) (GG genotype: P=0. 006, A carriers: P= 0. 001) significantly increased in the females regardless of the genotype. However, only in the male A carriers, HDL-C (P= 0. 011) and Apo A- I (P= 0. 041) significantly increased after the diet. CONCLUSION: The A allele at the LIPC -250G/A polymorphism is associated with the HC/LF diet induced HDL-C and Apo A-I concentration changes in the males.

No decrease of HDL cholesterol after 6 days of low fat and high carbohydrate diets in a young Chinese Han population.

More studies are needed on the hypertriacylglycerolemic effects of low fat and high carbohydrate (LF-HC) diet in young population, especially Chinese who generally have a diet containing lower fat and higher carbohydrate. To test them in a young Chinese Han population, 56 healthy subjects (22.89 +/- 1.80) years were given regular diet of 31% fat and 54% carbohydrate for 7 days, followed by LF-HC diet of 15% fat and 70% carbohydrate for 6 days, without total energy restriction. After the LF-HC diet, the male experienced an increase of high density lipoprotein (HDL) cholesterol and decreases of weight, body mass index (BMI), total cholesterol (TC), and LDL (low density lipoprotein) cholesterol (P < 0.05). The female experienced increased serum triacylglycerol and insulin, and decreased TC and LDL cholesterol (P < 0.05). When BMI was taken into account, all the subjects with low, medium, or high BMI experienced decreases of TC and LDL cholesterol although some changes were not significant. No significant decrease of HDL cholesterol was found, while significantly increased HDL cholesterol and apolipoprotein A-I (apo A-I) were found in the male subjects with low or high BMI (P < 0.05). Significant increase of triacylglycerol was observed only in the female subjects with low or medium BMI. In conclusion, subjects with different BMI and gender have different triacylglycerol and HDL cholesterol responses to LF-HC diets, and significant increase of HDL cholesterol and apolipoprotein A- I were observed in some young male subjects.

[Effects of high-carbohydrate/low-fat diet on serum lipid ratios in healthy young subjects].

OBJECTIVE: To investigate the effects of the short-term high-carbohydrate/low-fat (HC/LF) diet on the serum lipid ratios of healthy young subjects, which meant triglyceride to high-density lipoprotein cholesterol (TG/HDL-C), the logarithm of TG/HDL-C [log (TG/HDL-C)], low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL-C/HDL-C), and total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C). METHODS: 56 healthy participants with the average age of (22.89 +/- 1.80) years took the normal diet for 7 days followed by HC/LF diet for 6 days. Venous blood samples in fasting were collected between 7 : 00 and 10 : 00 AM on the 1st, the 8th and 14th day, respectively. Serum concentrations of triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C) were measured by regular methods. The ratios of TG/HDL-C, log (TG/HDL-C), LDL-C/HDL-C, and TC/ HDL-C were calculated. RESULTS: After HC/LF diet, both TG/HDL-C and log (TG/HDL-C) increased significantly for females (P < 0.05). For the males, these two ratios were decreased although not significant in statistics. When BMI or WHR was taken into account, the two ratios increased significantly after HC/LF diet, but only for the normal females (P < 0.05), not for the females with overall or abdominal adiposity. No significant changes of TG/HDL-C and log(TG/HDL-C) after HC/LF diet were observed between the males with different BMI or WHR. TC/HDL-C and LDL-C/HDL-C decreased significantly (P < 0.05) after HC/LF diet, but these changes were not found to associate with gender, BMI or WHR. CONCLUSION: The changes of TG/HDL-C and log (TG/HDL-C) induced by the short-term HC/LF diet are different in healthy young subjects with different gender, BMI or WHR, but there is no significant change happening to TC/HDL-C and LDL-C/HDL-C.

[Effects of a high-carbohydrate, low-fat diet on the levels of serum phospholipids and triglycerides].

OBJECTIVE: To study the effects of a High-carbohydrate, Low-fat (HC/LF) diet on the levels of phospholipids and triglycerides in serum and analyze their association with anthropometric indexs and serum biochemical traits. METHODS: 56 healthy volunteers had a HC/LF diet for 6 days. The body weight, waist circumference, hip circumference, biceps circumference, and skinfold thickness were measured before and after the HC/LF diet. Venous blood was taken after fasting of 12 hours. The levers of high density lipoprotein-phospholipid (HDL-PL), high density lipoprotein-triglyceride (HDL-TG), high density lipoprotein-cholesterol (HDL-C) were enzymatically determined after precipitation of serum apoB containing lipoproteins with phosphotungistic acid and non-LDL-phospholipid (NLDL-PL), non-LDL-triglyceride (NLDL-TG), non-LDL-Cholesterol (NLDL-C) levels were enzymatically determined after precipitation of serum LDL with polyethylene sulfate. The levels of serum LDL-PL, LDL-TG, and LDL-C were calculated by minus of non-LDL from serum PL, TG, and TC levels, respectively. The level of TRL-TG was calculated by minus of HDL-TG, LDL-TG from total TG. The level of serum insulin was measured by electrochemical luminescence. RESULTS: The levels of fasting serum PL, HDL-PL and LDL-PL decreased significantly after HC/LF diet, whereas the levels of TG, HDL-TG and insulin increased. Correlation analyses indicated that after HC/LF diet the change of serum PL (APL) had a negative correlation with the change of BMI(deltaBMI),a positive correlation with the change of HDL-TG(deltaHDL-TG) and insulin (delta insulin). The change of serum LDL-PL (deltaLDL-PL) had a negative correlation with deltaBMI and waist circumference (deltaAWC), meanwhile the change of HDL-PL (deltaHDL-PL) had a negative correlation with deltaHDL-TG, a positive correlation with the change of HDL-C (deltaHDL-L). A positive correlation existed between deltaHDL-TG and wais/hip circumference ratio (deltaW/H). CONCLUSION: HC/LF diet can decrease serum PL, HDL-PL level but increase serum levels of TG and insulin. The change of serum PL level had a negative correlation with deltaBMI,a positive correlation with deltaHDL-TG and delta insulin.