Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol

The effects of estradiol benzoate (EB) and estradiol cypionate (EC) on induction of ovulation after a synchronized LH surge and on fertility of Bos indicus females submitted to timed AI (TAI) were evaluated. In Experiment 1, ovariectomized Nelore heifers were used to evaluate the effect of EB (n = 5) and EC (n = 5) on the circulating LH profile. The LH surge timing (19.6 and 50.5 h; P = 0.001), magnitude (20.5 and 9.4 ng/mL; P = 0.005), duration (8.6 and 16.5 h; P = 0.001), and area under the LH curve (158.6 and 339.4 ng/mL; P = 0.01) differed between the EB and EC treatments, respectively. In Experiment 2 (follicular responses; n = 60) and 3 (pregnancy per AI; P/AI; n = 953) suckled Bos indicus beef cows submitted to an estradiol/progesterone-based synchronization protocol were assigned to receive one of two treatments to induce synchronized ovulation: 1 mg of EB im 24 h after progesterone (P4) device removal or 1 mg of EC im at P4 device removal. There was no difference (P > 0.05) between EB and EC treatments on follicular responses (maximum diameter of the ovulatory follicle, 13.1 vs. 13.9 mm; interval from progesterone device removal to ovulation, 70.2 vs. 68.5 h; and ovulation rate, 77.8 vs. 82.8%, respectively). In addition, P/AI was similar (P < 0.22) between the cows treated with EB (57.5%; 277/482) and EC (61.8%; 291/471). In conclusion, despite pharmacologic differences, both esters of estradiol administered either at P4 device removal (EC) or 24 h later (EB) were effective in inducing an LH surge which resulted in synchronized ovulations and similar P/AI in suckled Bos indicus beef cows submitted to TAI. (C) 2012 Elsevier Inc. All rights reserved.

Factors controlling water-column respiration in rivers of the central and southwestern Amazon Basin

We examined the factors controlling the variability in water-column respiration rates in Amazonian rivers. Our objectives were to determine the relationship between respiration rates and the in situ concentrations of the size classes of organic carbon (OC), and the biological source (C-3 and C-4 plants and phytoplankton) of organic matter (OM) supporting respiration. Respiration was measured along with OC size fractions and dissolved oxygen isotopes (delta O-18-O-2) in rivers of the central and southwestern Amazon Basin. Rates ranged from 0.034 mu mol O-2 L-1 h(-1) to 1.78 mu mol O-2 L-1 h(-1), and were four-fold higher in rivers with evidence of photosynthetic production (demonstrated by delta O-18-O-2<24.2 parts per thousand) as compared to rivers lacking such evidence (delta O-18-O-2>24.2 parts per thousand; 1.35 +/- 0.22 vs. 0.30 +/- 0.29 mu mol L-1 h(-1)). Rates were likely elevated in the former rivers, which were all sampled during low water, due to the stimulation of heterotrophic respiration via the supply of a labile, algal-derived substrate and/or the occurrence of autotrophic respiration. The organic composition of fine particulate OM (FPOM) of these rivers is consistent with a phytoplankton origin. Multiple linear regression analysis indicates that [FPOC], C:N-FPOC ratios, and [O-2] account for a high amount of the variability in respiration rates (r(2) = 0.80). Accordingly, FPOC derived from algal sources is associated with elevated respiration rates. The delta C-13 of respiration-derived CO2 indicates that the role of phytoplankton, C-3 plants, and C-4 grasses in supporting respiration is temporally and spatially variable. Future scaling work is needed to evaluate the significance of phytoplankton production to basin-wide carbon cycling.

Lasiodiplodan, an exocellular (1 -> 6)-beta-d-glucan from Lasiodiplodia theobromae MMPI: production on glucose, fermentation kinetics, rheology and anti-proliferative activity

Lasiodiplodan, an exopolysaccharide of the (1 -> 6)-beta-d-glucan type, is produced by Lasiodiplodia theobromae MMPI when grown under submerged culture on glucose. The objective of this study was to evaluate lasiodiplodan production by examining the effects of carbon (glucose, fructose, maltose, sucrose) and nitrogen sources (KNO3, (NH4)(2)SO4, urea, yeast extract, peptone), its production in shake flasks compared to a stirred-tank bioreactor, and to study the rheology of lasiodiplodan, and lasiodiplodan's anti-proliferative effect on breast cancer MCF-7 cells. Although glucose (2.05 +/- A 0.05 g L-1), maltose (2.08 +/- A 0.04 g L-1) and yeast extract (2.46 +/- A 0.06 g L-1) produced the highest amounts of lasiodiplodan, urea as N source resulted in more lasiodiplodan per unit biomass than yeast extract (0.74 +/- A 0.006 vs. 0.22 +/- A 0.008 g g(-1)). A comparison of the fermentative parameters of L. theobromae MMPI in shake flasks and a stirred-tank bioreactor at 120 h on glucose as carbon source showed maximum lasiodiplodan production in agitated flasks (7.01 +/- A 0.07 g L-1) with a specific yield of 0.25 +/- A 0.57 g g(-1) and a volumetric productivity of 0.06 +/- A 0.001 g L-1 h(-1). A factorial 2(2) statistical design developed to evaluate the effect of glucose concentration (20-60 g L-1) and impeller speed (100-200 rpm) on lasiodiplodan production in the bioreactor showed the highest production (6.32 g L-1) at 72 h. Lasiodiplodan presented pseudoplastic behaviour, and the apparent viscosity increased at 60A degrees C in the presence of CaCl2. Anti-proliferative activity of lasiodiplodan was demonstrated in MCF-7 cells, which was time- and dose-dependent with an IC50 of 100 mu g lasiodiplodan mL(-1).