Effects of salinity on chlorophyll fluorescence and CO<Subscript>2</Subscript> fixation in C<Subscript>4</Subscript> estuarine grasses

The effects of salinity (sea water at 0 ‰ versus 30 ‰) on gross rates of O₂ evolution (J _O2) and net rates of CO₂ uptake (P _N) were measured in the halotolerant estuarine C₄ grasses Spartina patens, S. alterniflora, S. densiflora, and Distichlis spicata in controlled growth environments. Under high irradiance, salinity had no significant effect on the intercellular to ambient CO₂ concentration ratio (C _i/C _a). However, during photosynthesis under limiting irradiance, the maximum quantum efficiency of CO₂ fixation decreased under salinity across species, suggesting there is increased leakage of the CO₂ delivered to the bundle sheath cells by the C₄ pump. Growth under salinity did not affect the maximum intrinsic efficiency of photosystem 2, PS2 (F_V/F_M) in these species, suggesting salinity had no effect on photosynthesis by inactivation of PS2 reaction centers. Under saline conditions and high irradiance, P _N was reduced by 75 % in Spartina patens and S. alterniflora, whereas salinity had no effect on P _N in S. densiflora or D. spicata. This inhibition of P _N in S. patens and S. alterniflora was not due to an effect on stomatal conductance since the ratio of C _i/C _a did not decrease under saline conditions. In growth with and without salt, P _N was saturated at ∼500 μmol(quantum) m⁻² s⁻¹ while J _O2 continued to increase up to full sunlight, indicating that carbon assimilation was not tightly coupled to photochemistry in these halophytic species. This increase in alternative electron flow under high irradiance might be an inherent function in these halophytes for dissipating excess energy.     

Exogenously applied GA4 is converted to GA1 in seedlings of Salix

Gibberellin A₄ (GA₄) is biologically active in Salix pentandra and is able to induce stem elongation in seedlings grown under short day (SD) conditions, as well as in seedlings grown under long day (LD) conditions and treated with a growth retardant BX-112. [³H₂]GA₄ and [²H₂]GA₄ were applied to seedlings and leaf and stem explants of S. pentandra, and metabolites were studied using HPLC and GC-MS. After application of [³H₂]GA₄ to seedlings of S. pentandra, one of the three main radioactive metabolites in the free acid fraction had retention properties similar to GA₁. Using [²H₂]GA₄, this compound was identified by GC-MS with SIM as [²H₂]GA₁ both from short day-grown and BX-112-treated seedlings, as well as in leaf and stem explants. After injection of GA₄ into a mature leaf, GA₁ was mainly found in the elongating stem tissue. Thus, the possibility that the biological activity of GA₄ in Salix is due to its conversion to GA₁ cannot be excluded.     

Non-Alcoholic Fatty Liver Disease as a Predictor of Atrial Fibrillation in Middle-Aged Population (OPERA Study)

Non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) are widespread diseases and have multiple common risk factors and comorbidities. No studies of association between ultrasonography-diagnosed NAFLD and AF exist in other than diabetic population. The goal of this prospective study was to study the value of NAFLD as a predictor of atrial fibrillation. This study had 958 subjects from the OPERA (Oulu Project Elucidating Risk of Atherosclerosis) cohort, and the mean follow-up time was 16.3 years. NAFLD was diagnosed if the subject had fatty liver in ultrasonography and no excess alcohol intake. AF was followed in the National Registers. In this study 249 subjects (26.0%) had NAFLD and 37 (14.9%) of these had AF whereas only 56 (7.9%) of those without NAFLD experienced AF during the follow-up time (p = 0.001). In the multiple Cox regression analysis including potential confounders (age, sex, study group, diabetes, body mass index (BMI), waist circumference, alcohol consumption, smoking, serum alanine aminotransferase concentration (ALT), systolic blood pressure, quick index, left ventricular mass index, left atrial diameter, coronary artery disease (CAD), atrial natriuretic peptide (ANP) and high sensitive C-reactive protein (hs-CRP)), NAFLD remained as an independent predictor of AF (Adjusted OR, 1.88 (95% Confidence interval (CI) 1.03–3.45)). In conclusion, our data shows that NAFLD is independently associated with the risk of AF.     

Endogenous gibberellins in young seedlings of wheat (Triticum aestivum) cultivars

Gibberellins A₁, A₃, A₄ and A₇ were identified by combined gas chromatography mass spectrometry (GC-MS) in leaf and stem tissues of 17-day-old seedlings of wheat ( Triticum aestivum L. ), cvs Siete Cerros (semi-dwarf, Rht1) and Møystad (tall), of F₁, hybrids from the cross Møystad × Siete Cerros and of 2 selected lines from the cross Møystad x Sonora 64 (Rht1 and Rht2). GA, and GA, were identified by full scan mass spectra separately in all 5 extracts, GA₄ and GA₇, were identified by selected ion monitoring in a bulked fraction. About 90% of the biological activity (Tan-ginbozu dwarf rice bioassay) in all 5 extracts was due to the GA₁/GA₃-fraction.     

Effects of twelve-month strength training subsequent to twelve-month stretching exercise in treatment of chronic neck pain

Previously, in a randomized study, we showed that women with chronic neck pain were able to perform intensive training for neck and shoulder muscles and that the increase in strength was accompanied by a reduction in pain and disability. The changes were significantly greater in the training groups compared with controls. The aim of the present study was to evaluate whether the controls would achieve similar results. Thus, 59 women in the control group initiated high-intensity strength training. Maximal isometric neck strength increased by 44% in both flexion and rotation and 27% in extension at the 2-year follow-up. Statistically and also clinically significant decreases in neck pain and disability indices occurred. Stretching and aerobic exercising during the first follow-up year produced only minor changes in both subjective and functional measures. Adding progressive strength training for the second year led to a significant improvement in neck strength and also to a considerable decrease in the pain and disability scores. Thus, to achieve effective rehabilitation in cases of chronic neck pain, a combination of strength training and stretching exercises are recommended.     

Identification of the human cytochrome P450 enzymes involved in the in vitro biotransformation of lynestrenol and norethindrone

This study examined the cytochrome P450 (CYP) enzyme selectivity of in vitro bioactivation of lynestrenol to norethindrone and the further metabolism of norethindrone. Screening with well-established chemical inhibitors showed that the formation of norethindrone was potently inhibited by CYP3A4 inhibitor ketoconazole (IC(50)=0.02 microM) and with CYP2C9 inhibitor sulphaphenazole (IC(50)=2.13 microM); the further biotransformation of norethindrone was strongly inhibited by ketoconazole (IC(50)=0.09 microM). Fluconazole modestly inhibited both lynestrenol bioactivation and norethindrone biotransformation. Lynestrenol bioactivation was mainly catalysed by recombinant human CYP2C9, CYP2C19 and CYP3A4; rCYP3A4 was responsible for the hydroxylation of norethindrone. A significant correlation was observed between norethindrone formation and tolbutamide hydroxylation, a CYP2C9-selective activity (r=0.63; p=0.01). Norethindrone hydroxylation correlated significantly with model reactions of CYP2C19 and CYP3A4. The greatest immunoinhibition of lynestrenol bioactivation was seen in incubations with CYP2C-Ab. The CYP3A4-Ab reduced norethindrone hydroxylation by 96%. Both lynestrenol and norethindrone were weak inhibitors of CYP2C9 (IC(50) of 32 microM and 46 microM for tolbutamide hydroxylation, respectively). In conclusion, CYP2C9, CYP2C19 and CYP3A4 are the primary cytochromes in the bioactivation of lynestrenol in vitro, while CYP3A4 catalyses the further metabolism of norethindrone.     

Vegetation Dynamics and Forest Landscape Restoration in the Upper Min River Watershed, Sichuan, China

The Upper Min River (UMR) watershed, with an area of 23,000 km² in the Upper Yangtze basin in Sichuan province, is ecologically and environmentally fragile. This situation is due to natural catastrophes and increasing anthropogenic disturbance. Forest cover has decreased dramatically, especially along the main Min River. Restoration of the vegetation in a watershed needs to consider the natural vegetation distribution and dynamics. In the UMR watershed, 625 sample plots were randomly placed to study the soil types, current vegetation distribution, vegetation dynamics, afforestation, and potential tree species for restoration. We investigated the relationship between vegetation types and soil orders, predicted the percentages of potential tree species for forest landscape restoration using logistic regression, identified priority areas for rapid restoration, and pinpointed areas for forest restoration where low precipitation is a constraint. The results showed that the vegetation types were well correlated with soil orders, and the latter could be used to deduce the potential vegetation for areas of degraded secondary forest. Priority areas for rapid restoration were demonstrated, and the difficult areas with precipitation as a limiting factor for vegetation restoration were specified. Suitable tree species were suggested for restoration on different soil orders at different elevations.     

Structural, biochemical, and physiological characterization of photosynthesis in two C4 subspecies of Tecticornia indica and the C3 species Tecticornia pergranulata (Chenopodiaceae)

Among dicotyledon families, Chenopodiaceae has the most C(4) species and the greatest diversity in structural forms of C(4). In subfamily Salicornioideae, C(4) photosynthesis has, so far, only been found in the genus Halosarcia which is now included in the broadly circumscribed Tecticornia. Comparative anatomical, cytochemical, and physiological studies on these taxa, which have near-aphyllous photosynthetic shoots, show that T. pergranulata is C(3), and that two subspecies of T. indica (bidens and indica) are C(4) (Kranz-tecticornoid type). In T. pergranulata, the stems have two layers of chlorenchyma cells surrounding the centrally located water storage tissue. The two subspecies of T. indica have Kranz anatomy in reduced leaves and in the fleshy stem cortex. They are NAD-malic enzyme-type C(4) species, with mesophyll chloroplasts having reduced grana, characteristic of this subtype. The Kranz-tecticornoid-type anatomy is unique among C(4) types in the family in having groups of chlorenchymatous cells separated by a network of large colourless cells (which may provide mechanical support or optimize the distribution of radiation in the tissue), and in having peripheral vascular bundles with the phloem side facing the bundle sheath cells. Also, the bundle sheath cells have chloroplasts in a centrifugal position, which is atypical for C(4) dicots. Fluorescence analyses in fresh sections indicate that all non-lignified cell walls have ferulic acid, a cell wall cross-linker. Structural-functional relationships of C(4) photosynthesis in T. indica are discussed. Recent molecular studies show that the C(4) taxa in Tecticornia form a monophyletic group, with incorporation of the Australian endemic genera of Salicornioideae, including Halosarcia, Pachycornia, Sclerostegia, and Tegicornia, into Tecticornia.     

Solubilization and partial purification of human placental cytochromes P-450

Human placental mitochondrial and microsomal cytochrome P-450 (P-450) was solubilized with sodium cholate in the presence of Emulgen 911 and the solubilized preparations purified by phenyl-Sepharose and DEAE-cellulose column chromatography. The final preparations exhibited specific activities between 3.0 and 7.0 nmol P-450/mg protein implying a 30–115-fold purification over the starting material. Androstenedione exhibited type I spectral interaction with the microsomal P-450 and pregnenolone a reverse type I spectrum with mitochondrial P-450. Hydrophobic column chromatography proved to be a rapid and efficient initial purification step for placental P-450s.