Isolation of propionate degrading bacterium in co-culture with a methanogen from a cattle dung biogas plant

Various anaerobic hydrolytic and methanogenic bacteria active in cattle dung biogas plants are reported in the literature. Anaerobic bacteria with ability to use volatile fatty acids constitute a vital bridge between hydrolytic bacteria and methanogenic bacteria. The present paper describes the isolation ofSyntrophobacter wolinii a propionate degrading bacterium in co-culture with a hydrogen utilizing methanogenviz.,Methanobacterium formicicum from the fermenting slurry of cattle dung biogas plant. Earlier studies on propionate and butyrate degradation indicatedMethanospirillum hungatei as the hydrogen utilizing partner of the co-culture whereas in the present studies this was not the case. Temperature 35° C, pH 7.5 and 20 mM of propionate were found optimal for growth and activity of co-culture.     

The stimulatory effect of testosterone propionate and 17β-estradiol on 5′-methylthioadenosine phosphorylase activity in rat target tissues

The effect of castration and subsequent administration of 17β-estradiol and testosterone propionate on 5′-methylthioadenosine phosphorylase activity in rat target tissues was studied. Castration 34 days earlier resulted in a 95 reduction in ventral prostate 5′-methylthioadenosine phosphorylase activity and 16 days earlier in a 67% reduction in uterine 5′-methylthiodenosine phosphorylase activity. Four days of testosterone propionate administration stimulated ventral prostate 5′-methylhioadenosine phosphorylase activity 32% above castrate levels, which represented more than 50% of the intact control levels. 17β-Estradiol on the other hand stimulated uterine 5′-methylthioadenosine phosphorylase activity of 35% above castrate controls within 24h and with 3 days of continuous hormone treatment to within 97% of the intact control levels. However, castration and subsequent 17β-estradiol administration did not affect 5′-methylthioadenosine phosphorylase activity in rat liver and lung. Both prostate and uterine 5′-methylthioadenosine phosphorylase were shown to metabolize 5′-methylthioadenosine to 5′-methylthioribose through a 5′-methythiribose 1-phosphate intermediate. The data suggest that 5′-methylthioadenosine is not allowed to accumulate in rat target tissues even under conditions which are known to stimulate polyamine synthesis.     

Methane production from propionate by methanogenic mixed culture

Abstract The association of Desulfobulbus sp. with Methanosarcina barkeri 227 was able to produce CH₄ from propionate in the presence of sulfate, if a sufficient amount of ferrous iron was added to the media in order to trap the soluble sulfides produced from sulfate. In the absence of ferrous iron, soluble sulfides inhibited the acetoclastic reaction. Attempts to cultivate Desulfobulbus sp. with H₂-utilising methanogenic bacteria in the absence of sulfate did not succeed.     

Direct anabolic metabolism of three-carbon propionate to a six-carbon metabolite occurs in vivo across tissues and species

Anabolic metabolism of carbon in mammals is mediated via the one- and two-carbon carriers S-adenosyl methionine and acetyl-coenzyme A. In contrast, anabolic metabolism of three-carbon units via propionate has not been shown to extensively occur. Mammals are primarily thought to oxidize the three-carbon short chain fatty acid propionate by shunting propionyl-CoA to succinyl-CoA for entry into the TCA cycle. Here, we found that this may not be absolute as, in mammals, one nonoxidative fate of propionyl-CoA is to condense to two three-carbon units into a six-carbon trans-2-methyl-2-pentenoyl-CoA (2M2PE-CoA). We confirmed this reaction pathway using purified protein extracts provided limited substrates and verified the product via LC-MS using a synthetic standard. In whole-body in vivo stable isotope tracing following infusion of ¹³C-labeled valine at steady state, 2M2PE-CoA was found to form via propionyl-CoA in multiple murine tissues, including heart, kidney, and to a lesser degree, in brown adipose tissue, liver, and tibialis anterior muscle. Using ex vivo isotope tracing, we found that 2M2PE-CoA also formed in human myocardial tissue incubated with propionate to a limited extent. While the complete enzymology of this pathway remains to be elucidated, these results confirm the in vivo existence of at least one anabolic three- to six-carbon reaction conserved in humans and mice that utilizes propionate.     

Testosterone affects reproductive success by influencing extra-pair fertilizations in male dark-eyed juncos (Aves: Junco hyemalis)

Monogamous male birds typically allocate less effort to courtship and more to parental behaviour than males of polygynous species. The seasonal pattern of testosterone (T) secretion varies accordingly. Monogamous males exhibit a spring peak in plasma T followed by lower levels during the parental phase, while males of polygynous species continue to court females and maintain T at higher levels. To determine whether testosterone underlies the trade-off between mating and parental effort, we treated male dark-eyed juncos (Junco hyemalis) with exogenous T and compared the reproductive success (RS) of T-treated males (T-males) to that of controls. T-males had lower apparent annual RS than controls, probably because elevated T reduced parental care. Nevertheless, annual genetic RS of the treatment groups was similar because (i) T-males suffered fewer losses in genetic RS due to extra-pair fertilizations (EPFs), and (ii) T-males gained more genetic RS through their own EPFs. This is the first hormonal manipulation of an avian phenotype shown to have influenced male RS through EPFs. Together with other studies, it suggests that testosterone may have mediated the evolution of inter- and intraspecific differences in allocation of reproductive effort to mate attraction and parental care.     

The impact of nandrolone decanoate and growth hormone on biosynthesis of steroids in rats

Growth hormone (GH) and anabolic androgenic steroids (AAS) are commonly used in sports communities. Several studies have suggested an association between GH and AAS. We have investigated the impact of GH in rats treated with nandrolone decanoate (ND). Male Wistar rats received ND (15 mg/kg) every third day during three weeks and were subsequently treated with recombinant human GH (1.0 IU/kg) for ten consecutive days. Plasma samples were collected and peripheral organs (i.e. heart, liver, testis and thymus) were dissected and weighed. Concentration of thirteen endogenous steroids was measured in the rat plasma samples using high specificity LC–MS/MS methods. Seven steroids were detected and quantified, and concentrations of estrone, testosterone, and androstenedione were significantly different among the groups, while concentrations of pregnenolone, DHEA, 17-hydroxyprogesterone and corticosterone were not altered. Administration of rhGH alone altered the plasma steroid distribution, and the results demonstrated significantly increased concentrations of plasma estrone as well as decreased concentrations of testosterone and androstenedione in the ND-treated rats. Administration of rhGH to ND-pretreated rats did not reverse the alteration of the steroid distribution induced by ND. Administration of ND decreased the weight of the thymus, and addition of rhGH did not reverse this reduction. However, rhGH administration induced an enlargement of thymus. Taken together, the plasma steroid profile differed in the four groups, i.e. control, AAS, rhGH and the combination of AAS and rhGH treatment.     

Blend miscibility of cellulose propionate with poly(N-vinyl pyrrolidone-co-methyl methacrylate)

The blend miscibility of cellulose propionate (CP) with poly(N-vinyl pyrrolidone-co-methyl methacrylate) (P(VP-co-MMA)) was investigated. The degree of substitution (DS) of CP used ranged from 1.6 to >2.9, and samples for the vinyl polymer component were prepared in a full range of VP:MMA compositions. Through DSC analysis and solid-state ¹³C NMR and FT-IR measurements, we revealed that CPs of DS < 2.7 were miscible with P(VP-co-MMA)s of VP ≥ ∼10 mol% on a scale within a few nanometers, in virtue of hydrogen-bonding interactions between CP-hydroxyls and VP-carbonyls. When the DS of CP exceeded 2.7, the miscibility was restricted to the polymer pairs using P(VP-co-MMA)s of VP = ca. 10–40 mol%; the scale of mixing in the blends concerned was somewhat larger (ca. 5–20 nm), however. The appearance of such a “miscibility window” was interpretable as an effect of intramolecular repulsion in the copolymer component. Results of DMA and birefringence measurements indicated that the miscible blending of CP with the vinyl polymer invited synergistic improvements in thermomechanical and optical properties of the respective constituent polymers. Additionally, it was found that the VP:MMA composition range corresponding to the miscibility window was expanded by modification of the CP component into cellulose acetate propionate.     

24-Hour Changes in Circulating Prolactin,Follicle-Stimulating Hormone,Luteinizing Hormone,and Testosterone in Young Male Rats Subjected to Calorie Restriction

This work analyzes the effect of calorie restriction on the 24 h variation of pituitary-testicular function in young male Wistar rats by measuring the circulating levels of prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone. Control animals were provided an equilibrium calorie diet and the experimental animals a calorie-restriction diet equivalent to 66% of food restriction for four weeks starting on day 35 of life. Different groups of control and experimental rats were killed at 6 h intervals around the clock, beginning 1 h after light on (HALO). Compared to the control animals, the mean secretion of prolactin was augmented and that of LH and testosterone decreased in calorie-restricted rats, whereas FSH release remained unchanged. Significant changes in the 24 h secretory pattern of circulating prolactin, LH, and testosterone occurred in the calorie-restricted rats. These include the appearance of a second maximum of plasma prolactin at 21 HALO, blunting of the LH peak seen at 13 HALO, and phase-shift of the testosterone peak from 13 HALO in controls to 17 HALO in calorie-restricted rats. The significant positive correlation between individual LH and testosterone levels found in controls was no longer observed in calorie-restricted rats. Availability of nutrients presumably affects the mechanisms that modulate the circadian variation of the pituitary-gonadal axis in growing male rats.     

Women's intercollegiate athletic competition: Cortisol,testosterone, and the dual-hormone hypothesis as it relates to status among teammates

Recent research suggests that testosterone and cortisol jointly regulate dominance motivation and, perhaps, the status relationships that are affected by it. For this article, the results of six different studies of women's intercollegiate athletic competition were combined to give a sample size of almost ninety women for whom we had before- and after-competition values for salivary cortisol and testosterone for at least one and sometimes two competitions. For many of these women, we had surveys that allowed us to assess their status with teammates. In no matter what sport (soccer, softball, volleyball, and tennis) levels of salivary cortisol and testosterone increased when women participated in athletic competition. Salivary levels of C and T appear to rise in parallel during competition and increases in levels of one hormone are significantly related to increases in the other. Salivary levels of these hormones typically decreased for teammates who did not play but watched the competition from the sidelines. For women who played in two competitions, individual differences in the positive effect of competition on cortisol and testosterone were conserved from one competition to the next, affirming the personal consistency of endocrine responses to competition. Status with teammates was positively related to before-competition levels of testosterone, but only for women with relatively low before-competition levels of cortisol. This result provides novel support for the “dual-hormone hypothesis” as it relates to predicting social status in women's athletic teams — natural social groups of individuals who know each other and whose social hierarchy has evolved over the course of practice and play for at least one and, in some cases, several years of intercollegiate athletic competition.