Two new species of <Emphasis Type="Italic">Erythroxylum</Emphasis> sect. <Emphasis Type="Italic">Rhabdophyllum</Emphasis> (<Emphasis Type="Italic">Erythroxylaceae</Emphasis>) from north-eastern Brazil

Summary   Erythroxylum longisetulosum I. Loiola & M. F. Sales and E. timothei I. Loiola & M. F. Sales (sect. Rhabdophyllum) from north-eastern Brazil are described and illustrated, and their taxonomic and ecological relationships are discussed.     

Effect of variation in embryo stage on the establishment of pregnancy, and embryo survival and growth in ewes with two embryos

Embryos at different stages of development were transferred to recipient ewes on Day 6 to investigate the effect of variation in stage of development on embryo survival and growth. Three groups of ewes received 2 embryos that were at the same stage of development, Day 4, Day 6 or Day 8. A fourth group received 1 Day-4 and 1 Day-8 embryo. At autopsy on recipient Day 34 there were no significant differences in embryo survival (Day 4, 34%; Day 6, 50%; Day 8, 46%; and Day 4 and 8, 48%). Fetuses developing from Day-8 embryos were heavier than others (Day 4, 1.10 +/- 0.06 g; Day 6, 1.15 +/- 0.06 g; Day 8, 1.41 +/- 0.08 g; P less than 0.05). In Group 4 neither survival nor growth of embryos was significantly affected by the presence of an embryo at a different stage of development. The ability of the uterus to stimulate development of a relatively retarded embryo is confirmed. Apparently the uterus has less effect in slowing the development of advanced embryos.     

Differential PGE2 and cAMP production by allogeneic and syngeneic pregnant mice uteri

Prostaglandin E₂ (PGE₂) and cAMP production in allogeneic and syngeneic pregnant mice uteri, were measured in relation to the ratio of plasma estrogen/progesterone levels. PGE₂ generation by allopregnant uteri varied with the days of pregnancy. The increment of the prostanoid coincided with the increase in plasma estrogen concentration, whereas the decrement of its production was in parallel with the increment of plasma progesterone. The syngeneic pregnant uterus was unable to increase the release of PGE₂ above basal values during the whole pregnancy. The rise of PGE₂ production by the allogeneic pregnant uterus was correlated with an increase in cAMP levels. It is proposed that the pregnant mouse uterus increases its ability to release PGE₂ in response to an ovarian steroids.     

Inhibitory effect of a lipopeptide biosurfactant produced by Bacillus subtilis on planktonic and sessile cells of Trichosporon spp.

The present study aimed to investigate the inhibitory effect of a bacterial biosurfactant (TIM96) on clinical strains of Trichosporon. Additionally, the effect of TIM96 on the ergosterol content, cell membrane integrity, and the hydrophobicity of planktonic cells was assessed. The inhibitory activity of TIM96 against Trichosporon biofilms was evaluated by analyzing metabolic activity, biomass and morphology. MIC values ranged from 78.125 to 312.5 μg ml^?1 for TIM96; time-kill curves revealed that the decline in the number of fungal cells started after incubation for 6 h with TIM96 at both MIC and 2×MIC. The biosurfactant reduced the cellular ergosterol content and altered the membrane permeability and the surface hydrophobicity of planktonic cells. Incubation at 10×MIC TIM96 reduced cell adhesion by up to 96.89%, thus interfering with biofilm formation. This concentration also caused up to a 99.2% reduction in the metabolic activity of mature biofilms. The results indicate potential perspectives for the development of new antifungal strategies.     

Methanogenic and acidogenic activity test in an anaerobic thermophilic reactor

Summary The experimental conditions selected (addition to assay medium of micronutrients, macronutrients and pH control), the experimental design and the procedure for maximum acidogenic and methanogenic activity determination tests in thermophilic biomass, are presented. The proposed tests are highly reproducible and can be carried out in a short space of time. Specific tests are applied to measure the maximum acidogenic and methanogenic activities in lab-scale anaerobic reactors treating wine-distillery wastes in the thermophilic range (55°C).     

Isolation of ergosterol peroxide and its reversion to ergosterol in the pathogenic fungus Sporothrix schenckii

Ergosterol peroxide, a presumed product of the H_{_2}O_{_2}-dependent enzymatic oxidation of ergosterol, has been isolated from yeast forms of the pathogenic fungus Sporothrix schenckii. The substance, which may have a role in fungal virulence, has been characterized mainly using spectroscopic methods (¹H and ¹³C nuclear magnetic resonance and high resolution mass spectra). The purified compound showed a molecular formula of C_{_28}H_{_44}O_{_3}, displaying characteristic features of epidioxy sterols and was reverted to ergosterol when submitted to S. schenckii enzymatic extract. This revised version was published online in June 2006 with corrections to the Cover Date.     

A Convenient Trip: an Analysis of the Impact of Hitchhiker Ants on Forager Transport Rates

During foraging, leaf-cutting ant workers of different size classes perform various tasks along foraging trails. Commonly, small workers called hitchhikers climb on leaf fragments imposing an extra transport cost, so their presence is thought to reduce the individual foraging performance. There are four main hypotheses which may explain the occurrence of hitchhikers and a different behavioral act related to their role can be predicted for each. Hitchhiker behavior was observed considering these hypotheses and the effect of the hitchhikers on the walking speed and transport rate of foragers was evaluated. The behavioral registers were obtained from 1371 hitchhikers on foraging trails of Acromyrmex subterraneus subterraneus nests in the field. To verify the influence of hitchhikers on walking speed and transport rate, 239 foragers with hitchhikers and 250 foragers transporting only leaf fragments were analyzed. The walking speed, burden and transport rate of each forager were calculated. Data indicated not only that hitchhikers are vigilant but that they remain motionless on the leaf fragment probably in order to reduce the impact of their presence for the loaded forager. The impact of their presence is verified through walking speed reduction but as they ride preferentially on larger workers who transport larger leaf fragments, there are no losses in the individual transport rate. The transporter selection made by the hitchhiker ensures at the same time enhanced protection against phorid parasitoids and the maintenance of the leaf transport rate.     

Monitoring the ex‐vivo expansion of human mesenchymal stem/stromal cells in xeno‐free microcarrier‐based reactor systems by MIR spectroscopy

Human mesenchymal stem/stromal cells (MSCs) have received considerable attention in the field of cell‐based therapies due to their high differentiation potential and ability to modulate immune responses. However, since these cells can only be isolated in very low quantities, successful realization of these therapies requires MSCs ex‐vivo expansion to achieve relevant cell doses. The metabolic activity is one of the parameters often monitored during MSCs cultivation by using expensive multi‐analytical methods, some of them time‐consuming. The present work evaluates the use of mid‐infrared (MIR) spectroscopy, through rapid and economic high‐throughput analyses associated to multivariate data analysis, to monitor three different MSCs cultivation runs conducted in spinner flasks, under xeno‐free culture conditions, which differ in the type of microcarriers used and the culture feeding strategy applied. After evaluating diverse spectral preprocessing techniques, the optimized partial least square (PLS) regression models based on the MIR spectra to estimate the glucose, lactate and ammonia concentrations yielded high coefficients of determination (R² ≥ 0.98, ≥0.98, and ≥0.94, respectively) and low prediction errors (RMSECV ≤ 4.7%, ≤4.4% and ≤5.7%, respectively). Besides PLS models valid for specific expansion protocols, a robust model simultaneously valid for the three processes was also built for predicting glucose, lactate and ammonia, yielding a R² of 0.95, 0.97 and 0.86, and a RMSECV of 0.33, 0.57, and 0.09 mM, respectively. Therefore, MIR spectroscopy combined with multivariate data analysis represents a promising tool for both optimization and control of MSCs expansion processes. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:447–455, 2016