Accumulation of substrates of the anaphase-promoting complex (APC) during human cytomegalovirus infection is associated with the phosphorylation of Cdh1 and the dissociation and relocalization of APC subunits

Cell cycle dysregulation upon human cytomegalovirus (HCMV) infection of human fibroblasts is associated with the inactivation of the anaphase-promoting complex (APC), a multisubunit E3 ubiquitin ligase, and accumulation of its substrates. Here, we have further elucidated the mechanism(s) by which HCMV-induced inactivation of the APC occurs. Our results show that Cdh1 accumulates in a phosphorylated form that may prevent its association with and activation of the APC. The accumulation of Cdh1, but not its phosphorylation, appears to be cyclin-dependent kinase dependent. The lack of an association of exogenously added Cdh1 with the APC from infected cells indicates that the core APC also may be impaired. This is further supported by an examination of the localization and composition of the APC. Coimmunoprecipitation studies show that both Cdh1 and the subunit APC1 become dissociated from the complex. In addition, immunofluorescence analysis demonstrates that as the infection progresses, several subunits redistribute to the cytoplasm, while APC1 remains nuclear. Dissociation of the core complex itself would account for not only the observed inactivity but also its inability to bind to Cdh1. Taken together, these results illustrate that HCMV has adopted multiple mechanisms to inactivate the APC, which underscores its importance for a productive infection.     

A flower with several secretions: anatomy,secretion composition,and functional aspects of the floral secretory structures of Chelonanthus viridiflorus (Helieae—Gentianaceae)

Floral secretory structures have been reported for Gentianaceae; however, morphoanatomical studies of these glands are rare. We described the development and secretory activity of the colleters and nectaries throughout the floral development of Chelonanthus viridiflorus. We collected flower buds, flowers at anthesis, and fruits to be investigated using light and scanning electron microscopy. We performed histochemical tests on the secretion of colleters and used glycophyte to confirm the presence of glucose in nectar. Colleters are located on the ventral surface of sepals and nectaries occur in four regions: (i) the dorsal and (ii) ventral surfaces of sepals; (iii) apex of petals; and (iv) base of ovary. The colleters have a short peduncle and a secretory portion with homogeneous cells. They are active in flower buds and secrete polysaccharides and proteins. In flowers at anthesis, they begin to senescence presenting protoplast retraction, cell collapse, and lignification; these characteristics are intensified in fruit. The nectaries of sepals and petals have two to five cells surrounding a central cell through which the secretion is released. Nectaries are numerous, forming a nectariferous area on the dorsal surface of sepals, like that observed on petals, and can form isolated units on the ventral surface of sepals. They are active from flower buds to fruits. A region with secretory activity was identified at the base of the ovary. The secretion of colleters acts in the protection of developing organs, while nectaries are related to defenses against herbivores and the supply of nectar to potential robbers or pollinators.

     

Influence of feeding conditions on clavulanic acid production in fed-batch cultivation with medium containing glycerol

First, the effect of different levels of nitrogen source on clavulanic acid (CA) production was evaluated in batch cultivations utilizing complex culture medium containing glycerol and three different levels of soy protein isolate (SPI). Cellular growth, evaluated in terms of the rheological parameter K, was highest with a SPI concentration of 30 g.L⁻¹ (4.42 g.L⁻¹ N total). However, the highest production of CA (380 mg.L⁻¹) was obtained when an intermediate concentration of 20 g.L⁻¹ of SPI (2.95 g.L⁻¹ total N) was used. To address this, the influences of volumetric flow rate (F) and glycerol concentration in the complex feed medium (Cs_F) in fed-batch cultivations were investigated. The best experimental condition for CA production was F=0.01 L.h⁻¹ and Cs_F=120 g.L⁻¹, and under these conditions maximum CA production was practically twice that obtained in the batch cultivation. A single empirical equation was proposed to relate maximum CA production with F and Cs_F in fed-batch experiments.     

Evaluation of crosses of Holstein, Jersey or Brown Swiss sires x Holstein-Friesian/Gir dams. 2. Female liveweights

The liveweights of 100 females sired by Holstein (H), Jersey (J) or Brown Swiss (BS) bulls out of Holstein-Friesian x Gir dams of 1/2 to 3/4 Holstein-Friesian fraction were compared. The animals were kept in a single herd under the same management. The data were analyzed separately for four age categories by least squares techniques. The models for cows and heifers older than 18 months included the fixed effects of breed of sire, Bos taurus fraction, season of weighing, days in milk class (for cows only), pregnancy status class, year and the random effect of animal nested within breed of sire x B. taurus fraction subclasses. The models for younger heifers included the same effects except for lactation and pregnancy status. Based on 2937 observations, the mean weights for 0- to 6-month-old calves for the groups with H, J or BS sires were 88 +/- 1, 77 +/- 1 and 75 +/- 1 kg, respectively, the mean weights for 1-year-old heifers were 168 +/- 2, 159 +/- 2 and 155 +/- 1 kg, for 2-year-old heifers, 327 +/- 4, 303 +/- 4 and 319 +/- 4 kg, for 3-year-old heifers, 380 +/- 5, 369 +/- 8 and 390 +/- 4 kg and for cows, 464 +/- 3, 413 +/- 2 and 478 +/- 2 kg. Cubic growth curves, which were different in the three sire breed groups, satisfactorily explained the cow weight changes with age (R(2)>or=0.98). Maximum weight was attained at 7.8, 9.5 and 9.2 years in cows with H, J or BS sires. Although breed of sire effects were not significant in heifers (P>0.05), those with H sires were the heaviest up to two years of age. The females with BS or J sires had similar weights up to one year of age, but thereafter the former reached similar weights as the females with H sires and declined less after attaining the maximum weight. The cows with J sires were the lightest at all ages. Since previous results showed similar protein and fat yields per day of calving interval in the three breed of sire groups, it is suggested that the lighter J crosses may be more economic than the other groups on account of their likely lower feed maintenance costs.     

Seagull influence on soil properties, chenopod shrub distribution, and leaf nutrient status in semi-arid Mediterranean islands

Concentration of seagulls in the Chafarinas Islands (three semi‐arid North African islets) induces profound changes in soil properties including eutrophication, salinization, acidification and nutrient imbalances. Soils of heavily seabird‐affected sites have significantly higher soluble K and NO₃ levels (>20‐fold), Zn and Fe availability (>5‐fold), water‐retention capacity (>40% increase) and ¹⁵N enrichment, compared with control sites. These seabird‐induced soil changes are paralleled by (i) different patterns of abundance of the two main chenopod shrubs: Suaeda vera abundance is higher (>30‐fold) in seabird‐affected sites while Salsola oppositifolia largely dominates in low‐affected areas. No differences were found for Atriplex halimus. The abundance of the first two species may be largely explained by changes in soil soluble K‐to‐available Ca ratio whose value depends of the interaction between seabird products and soil constituents; (ii) significant increases in leaf N, P and Zn levels, and in all K ratios, paralelled by a decrease in Ca, in Salsola; but only by increased K/Na and P/Ca ratios in Suaeda leaves. These changes were significantly correlated to changes in species abundances; (iii) an increase of δ¹⁵N, paralleled by a decrease in δ¹³C values, in Salsola leaves but not in Suaeda.
Conjoint analysis of the seabird‐related changes in soil properties, species abundance, leaf composition and differential response to the seabird‐induced fertilization/severity gradient of the two main chenopod shrub species, has led us to propose an explanatory hypothesis of seagull‐soil‐shrub relationships. According to this, the seagull‐induced soil changes, mediated by processes of (in)tolerance‐facilitation, play a main role in determining the abundance and the leaf nutrient status of the studied chenopod shrubs, which have contrasting physiological adaptations.     

Seed removal in two coexisting oak species: ecological consequences of seed size, plant cover and seed-drop timing

Seed predation and dispersal can critically influence plant community structure and dynamics. Inter‐specific differences arising at these early stages play a crucial role on tree recruitment patterns, which in turn could influence forest dynamics and species segregation in heterogeneous environments such as Mediterranean forests. We investigated removal rates from acorns set onto the ground in two coexisting Mediterranean oak species –Quercus canariensis and Q. suber– in southern Spain. We developed maximum likelihood estimators to investigate the main factors controlling probabilities of seed removal and to describe species‐specific functional responses. To account for inter‐specific differences in seed‐drop timing, two experiments were established: a simultaneous exposure of acorns of the two species (synchronous experiments) and a seed exposure following their natural seed‐drop phenology (diachronic experiments). A total of 1536 acorns were experimentally distributed along a wide and natural gradient of plant cover, and removal was periodically monitored for three months at two consecutive years (with contrasting differences in seed production and thus seed availability on the ground). The probability of seed removal increased with plant cover (leaf area index, LAI) for the two oak species. Inter‐specific differences in acorn removal were higher in open areas and disappeared in closed microhabitats, especially during a non‐mast year. Despite later seed‐drop, Q. suber acorns were removed faster and at a higher proportion than those of Q. canariensis. The higher probability of seed removal for this species could be attributed to its larger seed size compared to Q. canariensis, as inter‐specific differences were less pronounced when similar sized acorns were exposed. Inter‐specific differences in seed removal, arising from seed size variability and microsite heterogeneity, could be of paramount importance in oak species niche separation, driving stand dynamics and composition along environmental gradients.     

Impact of control measures and dynamics of sand flies in southern Brazil

We report the results of control measures introduced to reduce the density of sand flies in domiciles and subsequent monitoring of the effects of these measures on the sand fly populations. The most common species of sand flies were Nyssomyia neivai and Nyssomyia whitmani, which are naturally infected by Leishmania. A total of 268,382 (93.4%) sand flies were collected in ecotypes constructed with the aim of attracting sand flies, and 19,091 (6.6%) sand flies were collected in the ecotypes consisting of residences and other buildings. Human actions determine the growth or reduction of the sand fly population in human‐occupied space. Understanding the dynamics of sand flies in this environment can substantially contribute to the prevention of cutaneous leishmaniasis.     

Modeling temperature variations in a pilot plant thermophilic anaerobic digester

A model that predicts temperature changes in a pilot plant thermophilic anaerobic digester was developed based on fundamental thermodynamic laws. The methodology utilized two simulation strategies. In the first, model equations were solved through a searching routine based on a minimal square optimization criterion, from which the overall heat transfer coefficient values, for both biodigester and heat exchanger, were determined. In the second, the simulation was performed with variable values of these overall coefficients. The prediction with both strategies allowed reproducing experimental data within 5% of the temperature span permitted in the equipment by the system control, which validated the model. The temperature variation was affected by the heterogeneity of the feeding and extraction processes, by the heterogeneity of the digestate recirculation through the heating system and by the lack of a perfect mixing inside the biodigester tank. The use of variable overall heat transfer coefficients improved the temperature change prediction and reduced the effect of a non-ideal performance of the pilot plant modeled.     

Driving factors of the communities of phytophagous and predatory mites in a physic nut plantation and spontaneous plants associated

Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies.