Architecture of symbiotic dinoflagellate photosystem I-light-harvesting supercomplex in Symbiodinium.

Symbiodinium are the photosynthetic endosymbionts for corals and play a vital role in supplying their coral hosts with photosynthetic products, forming the nutritional foundation for high-yield coral reef ecosystems. Here, we determine the cryo-electron microscopy structure of Symbiodinium photosystem I (PSI) supercomplex with a PSI core composed of 13 subunits including 2 previously unidentified subunits, PsaT and PsaU, as well as 13 peridinin-Chl a/c-binding light-harvesting antenna proteins (AcpPCIs). The PSI-AcpPCI supercomplex exhibits distinctive structural features compared to their red lineage counterparts, including extended termini of PsaD/E/I/J/L/M/R and AcpPCI-1/3/5/7/8/11 subunits, conformational changes in the surface loops of PsaA and PsaB subunits, facilitating the association between the PSI core and peripheral antennae. Structural analysis and computational calculation of excitation energy transfer rates unravel specific pigment networks in Symbiodinium PSI-AcpPCI for efficient excitation energy transfer. Overall, this study provides a structural basis for deciphering the mechanisms governing light harvesting and energy transfer in Symbiodinium PSI-AcpPCI supercomplexes adapted to their symbiotic ecosystem, as well as insights into the evolutionary diversity of PSI-LHCI among various photosynthetic organisms.

Emergence of Antifungal Resistant Subclades in the Global Predominant Phylogenetic Population of Candida albicans.

Candida albicans remains the most common species causing invasive candidiasis. In this study, we present the population structure of 551 global C. albicans strains. Of these, the antifungal susceptibilities of 370 strains were tested. Specifically, 66.6% of the azole-nonsusceptible (NS)/non-wild-type (NWT) strains that were tested belonged to Clade 1. A phylogenetic analysis, a principal components analysis, the population structure, and a loss of heterozygosity events revealed two nested subclades in Clade 1, namely, Clade 1-R and Clade 1-R-α, that exhibited higher azole-NS/NWT rates (75.0% and 100%, respectively). In contrast, 6.4% (21/326) of the non-Clade 1-R isolates were NS/NWT to at least 1 of 4 azoles. Notably, all of the Clade 1-R-α isolates were pan-azole-NS/NWT that carried unique A114S and Y257H double substitutions in Erg11p and had the overexpression of ABC-type efflux pumps introduced by the substitution A736V in transcript factor Tac1p. It is worth noting that the Clade 1-R and Clade 1-R-α isolates were from different cities that are distributed over a large geographic span. Our study demonstrated the presence of specific phylogenetic subclades that are associated with antifungal resistance among C. albicans Clade 1, which calls for public attention on the monitoring of the future spread of these clones. IMPORTANCE Invasive candidiasis is the most common human fungal disease among hospitalized patients, and Candida albicans is the predominant pathogen. Considering the large number of infected cases and the limited alternative therapies, the azole-resistance of C. albicans brings a huge clinical threat. Here, our study suggested that antifungal resistance in C. albicans could also be associated with phylogenetic lineages. Specifically, it was revealed that more than half of the azole-resistant C. albicans strains belonged to the same clade. Furthermore, two nested subclades of the clade exhibited extremely high azole-resistance. It is worth noting that the isolates of two subclades were from different cities that are distributed over a large geographic span in China. This indicates that the azole-resistant C. albicans subclades may develop into serious public health concerns.

[EST-SSR identification of Lonicera japonica Thunb].

Simple and effective methods are needed for the identification of Chinese medicinal material species and their variety. Lonicera japonica Thunb. is one of Chinese herbal medicines widely demanded. A total of 3 705 EST-SSRs of L. japonica and 2 818 EST-SSRs of L. japonica var. chinensis Thunb. were identified from EST database in our lab. In average, there was one EST-SSR per 4.05 kb in L. japonica ESTs and per 7.49 kb in L. japonica var. chinensis ESTs, separately. The identified SSRs in L. japonica were consisted of 51.98% dinucleotide and 34.61% trinucleotide repeats, while SSRs in L. japonica var. chinensis had 57.45% dinucleotide and 30.09% trinucleotide. The results reviewed that the classes AG/TC and GAG/TCT were predominant in the dinucleotide motifs and the trinucleotide motifs, respectively. Total 87 EST-SSRs were identified of significant difference between L. japonica and L. japonica var. chinensis. PCR products were obtained from 52 L. japonica samples in 13 out of 15 SSR markers tested. The polymorphism in L. japonica, L. japonica var. chinensis and other honeysuckles could be distinguished by three markers (jp.ssr4, jp.ssr64 and jp.ssr65) tested.

Oral exposure to low-dose bisphenol A aggravates testosterone-induced benign hyperplasia prostate in rats.

The declining level of androgen during aging, associated with an inclining level of estrogen, has been hypothesized to be important in the development of benign prostatic hyperplasia (BPH). Within physiologic range, increasing estrogen levels can stimulate prostate to develop and permanently increase prostate size. As an estrogenic endocrine disruptor, bisphenol A (BPA) might be stimulatory to prostate development. We further hypothesized that low dose BPA could induce hyperplasia prostate to proliferate and aggravate the symptom of BPH in male SD rats. BPH was induced by testosterone and then treated with BPA (10, 30, or 90 µg/kg, i.g., daily), 17ß-estradiol (E(2); 50.0 µg/kg, s.c., daily), or vehicle for 4 weeks. We found that weight and volume in rats treated with low dose BPA (10 µg/kg) was higher than that of model control, and BPA significantly increased the relative weight of prostate (p < 0.01). For prostate lobes, BPA 10 µg/kg/day significantly increased relative weight of ventral prostate (VP), weight and relative weight of dorsolateral prostate (DLP) (p < 0.05). And histopathology results showed that height of epithelial cell (HEC) of VP and DLP in BPA group were significantly higher than that of model control (p < 0.01). BPA could also decrease testosterone level and increase prostate-specific antigen level. E(2) treatment also showed an obvious effect on relative weight of VP and DLP, HEC, and hormone levels. We concluded that environment exposure to low dose of BPA may induce prostate to proliferate and aggravate testosterone-induced benign hyperplasia prostate in rats.

The complete genome of Zunongwangia profunda SM-A87 reveals its adaptation to the deep-sea environment and ecological role in sedimentary organic nitrogen degradation.

BACKGROUND: Zunongwangia profunda SM-A87, which was isolated from deep-sea sediment, is an aerobic, gram-negative bacterium that represents a new genus of Flavobacteriaceae. This is the first sequenced genome of a deep-sea bacterium from the phylum Bacteroidetes. RESULTS: The Z. profunda SM-A87 genome has a single 5 128 187-bp circular chromosome with no extrachromosomal elements and harbors 4 653 predicted protein-coding genes. SM-A87 produces a large amount of capsular polysaccharides and possesses two polysaccharide biosynthesis gene clusters. It has a total of 130 peptidases, 61 of which have signal peptides. In addition to extracellular peptidases, SM-A87 also has various extracellular enzymes for carbohydrate, lipid and DNA degradation. These extracellular enzymes suggest that the bacterium is able to hydrolyze organic materials in the sediment, especially carbohydrates and proteinaceous organic nitrogen. There are two clustered regularly interspaced short palindromic repeats in the genome, but their spacers do not match any sequences in the public sequence databases. SM-A87 is a moderate halophile. Our protein isoelectric point analysis indicates that extracellular proteins have lower predicted isoelectric points than intracellular proteins. SM-A87 accumulates organic osmolytes in the cell, so its extracelluar proteins are more halophilic than its intracellular proteins. CONCLUSION: Here, we present the first complete genome of a deep-sea sedimentary bacterium from the phylum Bacteroidetes. The genome analysis shows that SM-A87 has some common features of deep-sea bacteria, as well as an important capacity to hydrolyze sedimentary organic nitrogen.

Differential metastasis-associated gene analysis of prostate carcinoma cells derived from primary tumor and spontaneous lymphatic metastasis in nude mice with orthotopic implantation of PC-3M cells.

The purpose of these studies was to explore the genes associated with invasion and metastasis of human prostatic carcinoma line PC-3M in nude mice. After PC-3M cells were inoculated in orthotopic site (prostate) in male nude mice for two months, tumor cells were isolated from primary tumor and lymph node metastasis in the same mouse, respectively. Cell invasion and adhesion ability in vitro were first compared between two cell lines. Then human metastasis-related genes differentially expressed between them were analyzed by utilizing cDNA microarray technique. The in vitro cell invasion and adhesion potential of tumor cells from lymph node metastasis was significantly higher than those from primary tumor, Metastasis-related genes differentially expressed between those two cell lines were identified, all of them were up-regulated in the tumor cells from lymph node metastasis and could be categorized as: (1) genes encoding cellular matrix-degrading proteolytic enzyme including cathepsin and MMP; (2) genes encoding transcription factors; (3) genes related to heterotypic adhesion of tumor cells; (4) genes encoding cell surface receptors. Moreover, Four genes were chosen for semi-quantitative RT-PCR analysis, they showed a consistent expression pattern with that of cDNA microarray analysis. We concluded that the lymph node metastasis in nude mice given an injection of PC-3M cells in the prostate is a selective process favoring the survival and growth of a special subpopulation derived from primary tumor with specific genetic alterations, which may play a pivotal role in the metastasis of prostate cancer. Identification and further characterization of these genes may allow a better understanding of lymphatic metastasis in prostate carcinoma.

Engineering of Ralstonia eutropha for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose.

Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with Ralstonia eutropha relies on the addition of propionate during fermentation, and propionate consumption is one of the major factors affecting the cost of PHBV production. In this study, 7 strains were obtained by genetic manipulating the methylcitric acid cycle and the methylmalonyl-CoA pathway in R. eutropha. Disruption of prpC1 and prpC2 genes did not affect cell growth and PHBV accumulation. All 7 strains were able to accumulation high amounts of PHBVs with 3HV fractions of 0.41-29.1 mol% during cultivation in flasks. Fermentation in 7.5-L fermenter showed that genetically engineered Rem-8 was able to yield biomass of 132.8 CDWg/L, of which 68.6% were PHBV with 3HV fraction of 26.0 mol% in the biopolymer, indicating promising potentials of commercialization in the future.

Vasodilative action of carbon monoxide on rat pulmonary artery in vitro.

The present study investigates the vasodilative action of carbon monoxide on rat pulmonary artery in vitro. After isolation of the pulmonary artery rings (PAR) from Wistar rats, an ACh concentration-response curve was generated; the PARs were incubated with the NOS inhibitor L-NAME (30 micromol/L, n=10) or the heme oxygenase inhibitor ZnPPIX (10 micromol/L)+L-NAME (30 micromol/L, n=10) for 30 min. After that, a second ACh concentration-response curve was elicited. Other isolated PARs were randomly divided into two groups: endothelium-intact group (n=8) and endothelium-denuded group (n=8). The effect of exogenous carbon monoxide (CO) on pulmonary arterial vessel tone was observed. The results showed that ACh induced a concentration-dependent pulmonary vasorelaxation. This relaxation disappeared after endothelium was denuded. The ACh induced relaxation was attenuated after pretreatment with 30 micromol/L L-NAME, and attenuated further after pretreatment with 10 micromol/L ZnPPIX+30 micromol/L L-NAME. Exogenous carbon monoxide relaxed pulmonary artery in both the endothelium-intact group and the endothelium-denuded group. These data suggest that ZnPPIX inhibits ACh induced endothelium-dependent pulmonary artery relaxation and that CO is an endothelium-derived relaxation factor, and exogenous CO can relax pulmonary artery.

[Effects and mechanisms of endotoxin pretreatment on lung of rat in endotoxemia].

OBJECTIVE: To observe the effects and mechanisms of endotoxin pretreatment on the rat lung in endotoxemia. METHODS: Eighty-four male Wistar rats were divided into seven groups (each group containing 12 rats): saline control and lipopolysaccharide (LPS)-treated 2 h, 4 h, 6 h groups and LPS-pretreated 2 h, 4 h, 6 h groups. LPS-pretreated rats were administrated with intraperitoneal injection of 0.25 mg/kg LPS. After 24 hours, they were injected with 0.5 mg/kg of LPS. Saline control and LPS-treated rats received an equivalent amount of saline. After 72 hours, LPS-treated and LPS-pretreated rats were intravenously injected with 10 mg/kg of LPS. An equivalent amount of saline was injected in the control rats. Blood was drawn from the carotid artery in LPS-treated and LPS-pretreated rats and sacrificed after intravenous injection of LPS 2, 4, 6 hours. Following saline injection of control rats, blood was drawn from the carotid artery after 6 hours. Arterial blood was drawn for blood gas analysis. The lungs were removed for detecting the mRNA levels of intercellular adhesion molecule-1 (ICAM-1) by reverse transcription polymerase chain reaction and the protein levels of inhibitor kappa B-alpha (I kappa B-alpha) by immunohistochemical staining. Bronchoalveolar lavage was performed in the right lung. Cell counts were evaluated with a light microscopy. The supernatant of bronchoalveolar lavage fluid (BALF) was assayed for the level of protein. The whole lung was weighed and the value was used to determine the lung-body index. The tissue was homogenized and centrifuged for the determination of myeloperoxidase enzyme (MPO) activity. RESULTS: The rats exposed to LPS alone demonstrated an increase in lung-body index, protein in BALF, and MPO activity in the lung tissue. In contrast, the rats exposed to LPS pretreatment exhibited a significant decrease in lung-body index, protein in BALF, and MPO activity. There was a significant decrease in the level of arterial bicarbonate in the LPS-treated rats in comparison with saline-treated and LPS-pretreated animals at 2 hours to 6 hours after LPS administration. The decrease of arterial bicarbonate was compensated by alveolar hyperventilation in LPS-treated animals, with a significant decrease in partial pressure of carbon dioxide. At the same time, partial pressure of oxygen decreased significantly compared with saline control animals and LPS-pretreated animals. LPS-treated rats showed a significant gradually increase in ICAM-1mRNA in the lung in comparison with the saline group. In contrast, ICAM-1mRNA levels in rats pretreated with LPS was lower than that in LPS-treated rats. In LPS-treated animals, LPS caused a decrease of I kappa B-alpha protein expression at 2 hours, returned to control level at 4 hours, and remained at 6 hours. There was no decrease of I kappa B-alpha protein expression in LPS-pretreated animals. CONCLUSION: The results in this study showed that administration of a small dose of LPS 72 hours before endotoxemia caused a attenuation effect on lung injury, which may be correlated to I kappa B-alpha expression induced by LPS pretreatment.

[Establishment of prostatic hyperplasia model with castration beagle canines].

OBJECTIVE: To establish a prostatic hyperplasia model with Beagle canines. METHODS: Twenty-four two-year-old male Beagle canines were divided into treatment and control groups at random and were administrated testosterone propionate (TP) through intramuscular injection two months after castration. Three treatment groups were given 0.8, 2.5 and 7.5 mg/kg TP respectively, and the control was given the same volume of vehicle. Two months later, half of the animals were killed and the serum and prostate were prepared. After the wet weight and volume of prostate were measured, the dihydrotestosterone (DHT) level of serum and prostate were detected with DHT radioimmunoassay (RIA) kit, and paraffine section from canine prostate was stained by the HE methods. Pictures were taken by digital camera under microscope, and all the pictures were analyzed by computer for epithelial cell height and acinar luminal area of prostate with micro image analysis software. The canine prostate volume was measured with ultrasonic diagnosis instrument before castration, at two months after castration and at two months after being given TP. RESULTS: The ultrasonic results showed that the prostate volumes of all the canines were smaller at two months after castration than before castration (P < 0.05), and after having been administrated TP for two months, and the prostate volumes of all treatment groups were larger than those of the control group (P < 0.01). The wet weight of the prostate of the treatment group was higher than that of the control group (P < 0.05), and both had dose-dependent relationship. The DHT level of serum and prostate of the canines became higher with the increase of TP dose. The results of micro image analysis showed that the acinar luminal area of prostate was enlarged, and the epithelial cell height increased with larger dose of TP. CONCLUSIONS: It is practicable to establish prostatic hyperplasia model in Beagle canines after two months of TP administration.

Comparative genomics provide insights into evolution of trichoderma nutrition style.

Saprotrophy on plant biomass is a recently developed nutrition strategy for Trichoderma. However, the physiology and evolution of this new nutrition strategy is still elusive. We report the deep sequencing and analysis of the genome of Trichoderma longibrachiatum, an efficient cellulase producer. The 31.7-Mb genome, smallest among the sequenced Trichoderma species, encodes fewer nutrition-related genes than saprotrophic T. reesei (Tr), including glycoside hydrolases and nonribosomal peptide synthetase-polyketide synthase. Homology and phylogenetic analyses suggest that a large number of nutrition-related genes, including GH18 chitinases, ß-1,3/1,6-glucanases, cellulolytic enzymes, and hemicellulolytic enzymes, were lost in the common ancestor of T. longibrachiatum (Tl) and Tr. dN/dS (ω) calculation indicates that all the nutrition-related genes analyzed are under purifying selection. Cellulolytic enzymes, the key enzymes for saprotrophy on plant biomass, are under stronger purifying selection pressure in Tl and Tr than in mycoparasitic species, suggesting that development of the nutrition strategy of saprotrophy on plant biomass has increased the selection pressure. In addition, aspartic proteases, serine proteases, and metalloproteases are subject to stronger purifying selection pressure in Tl and Tr, suggesting that these enzymes may also play important roles in the nutrition. This study provides insights into the physiology and evolution of the nutrition strategy of Trichoderma.

Effects of gestrinone on uterine leiomyoma and expression of c-Src in a guinea pig model.

AIM: To investigate the effect of gestrinone on uterine leiomyomas and the expression of c-Src, estradiol receptors (ER), and progesterone receptors (PR) in a guinea pig model. METHODS: After being oophorectomized, the guinea pigs were allocated into random groups. The model group was treated with estradiol benzoate (E2) for 16 weeks. In the gestrinone-treated groups, the animals were treated with E2 for 6 weeks in advance, and then in combination with gestrinone for 10 weeks. Histological examination was performed to evaluate whether there were leiomyoma features in the animals. The protein levels of c-Src, phospho-( 416)Src, ER, and PR were assayed by Western blotting and an immunohistochemical method. RESULTS: Morphological changes were observed in the myometrium of the guinea pig model, including an increase of uterine weights, proliferation of uterine smooth muscles, and the formation of nodules. High protein levels of c-Src, phospho- 416Src, ER, and PR were observed in the myometrium of the guinea pig model. In the gestrinone-treated group, there were no nodules observed. The histological features of the myometrium were similar to that of the control group. Low protein levels of c-Src, phospho-(416 )Src, ER, and PR were observed in the gestrinonetreated group. CONCLUSION: The upregulation of c-Src and phospho-(416 )Src indicated that the activity of c-Src is augmented in the uterine leiomyoma model. c-Src was associated with the formation of uterine leiomyomas in the model, and gestrinone markedly suppressed the growth of uterine leiomyomas in the model. Gestrinone inhibited not only the protein expression of ER and PR, but also c-Src and the autophosphorylation of c-Src in the guinea pig leiomyoma model.

[The roles of carbon monoxide on hypoxic pulmonary vasoconstriction].

AIM AND METHODS: To study the roles of carbon monoxide on hypoxic pulmonary vasoconstriction (HPV) by investigating the effects of exogenous carbon monoxide and heme oxygenase inhibitor ZnPPIX on hypoxic vasoconstriction reaction of isolated rat pulmonary arterial rings (PAR). RESULTS: Hypoxia caused constriction in PAR preconstricted by PE. Both ZnPPIX and carbon monoxide inhibited hypoxic pulmonary constriction significantly by increasing the cGMP level after hypoxia. CONCLUSION: ZnPPIX and exogenous carbon monoxide can inhibit HPV. The reduction of cGMP induced by the decreased of CO may be one of reasons of HPV.