Coffee rust genome measured using flow cytometry: does size matter?

The genome size of most rust species is unknown due, in part, to technical constraints, especially the difficulty in accessing spores to extract the nuclei for cytometry. Using the urediniospores of coffee rust, Hemileia vastatrix, an improved methodology involving flow cytometry was developed for accurate measurement of the nuclear genome size. The results revealed that the genome of this primitive rust fungus is unusually large – measuring 1C‐value = 0·75 pg (733·5 Mb) – significantly bigger than other species quantified thus far in the more advanced rust lineages. The evolutionary consequences and the potential ecological constraints of this large genome size are discussed in relation to the epidemiology of coffee rust.     

Carbon and nitrogen mineralization in soil of leguminous trees in a degraded pasture in northern Rio de Janeiro,Brazil

Use of legume trees can improve soil quality in degraded pastures. The aim of this study was to characterize C and N mineralization kinetics and estimate the potentially mineralizable C and N in soil under Mimosa caesalpiniifolia Benth. and Acacia auriculiformis A. Cunn.ex Benth. secondary forest and pasture in red-yellow latosols in southeast Brazil. We conducted a laboratory aerobic incubation experiment using a completely randomized design of four replicates and four types of plant cover using a modified version of the Stanford and Smith technique(1972) to study C and N mineralization potential.Potentially mineralizable N(N_o) ranged from 135 to170 mg kg-~(1). The predominant form of mineral N for all types of plant cover was N-NO_3~-. M. caesalpiniifolia was the only species that had a positive influence on N mineralization. Neither of the legumes influenced C mineralization in pasture or secondary forest. The model of N mineralization corresponded to a sigmoidal curve while C mineralization corresponded to an exponential curve,revealing that the N and C mineralization processes were distinct. N mineralized by M. caesalpiniifolia(216 kg of N ha~(-1)) was adequate to meet the N requirement for a livestock-forest system.     

Expression levels of mRNA-encoding PDGF receptors in goat ovaries and the influence of PDGF on the in vitro development of caprine pre-antral follicles

The aims of this study were to investigate the expression levels of mRNA for platelet-derived growth factor (PDGF) receptors (PDGFR-α and -β) in caprine follicles at different developmental stages and to evaluate the influence of PDGF on the in vitro development of pre-antral follicles. For this, goat primordial, primary and secondary follicles, as well as small (1-3 mm) and large (3-6 mm) antral follicles, were obtained, and PDGFR-α and -β mRNA levels were quantified by real-time PCR. Furthermore, pre-antral follicles (≥ 200 μm) were isolated from goat ovaries and cultured for 18 days in α- minimum essential medium supplemented with PDGF at 50 or 100 ng/ml, containing or not FSH. Real-time PCR showed highest PDGFR-α mRNA levels in secondary follicles, while PDGFR-β mRNA levels were highest in primary follicles onwards. Both receptors showed higher mRNA levels in granulosa/theca cells from small and large antral follicles than in their corresponding cumulus-oocyte complexes. In culture, the percentage of antrum formation was significantly higher in 100 ng/ml PDGF compared with the same PDGF concentration associated with FSH. After 18 days, PDGF in both concentrations associated with FSH promoted follicular growth significantly higher than the control. Moreover, the addition of FSH to 50 ng/ml PDGF positively influenced the follicular growth when compared with the same PDGF concentration in the absence of FSH. In conclusion, PDGF is important for early goat folliculogenesis, because the presence of PDGFR-α and -β mRNA was detected in all follicular categories, and PDGF associated with FSH stimulated the growth of goat pre-antral follicles isolated and cultured in vitro.     

Proteomic analyses of Ehrlichia ruminantium highlight differential expression of MAP1-family proteins

The Rickettsiales Ehrlichia ruminantium (ER) is the causative agent of heartwater, a fatal tick-borne disease of livestock in sub-Saharan Africa and in the Caribbean, posing strong economical constraints to livestock production. In an attempt to identify the most prominent proteins expressed by this bacterium, especially those encoded by the major antigenic protein 1 (map1) multigene family, a proteome map of ER cultivated in endothelial cells was constructed by using two dimensional gel electrophoresis combined with mass spectrometry. Among the sixty-four spots detected, we could identify only four proteins from the MAP1-family; the other proteins detected were mainly related to energy, amino acid and general metabolism (26%), to protein turnover, chaperones and survival (21%) and to information processes (14%) or classified as hypothetical proteins (23%). Additional studies on MAP1-family protein using immunochemical labeling also revealed that these proteins are differentially expressed along the bacterium life cycle, presenting different structural organization. Interestingly, when infectious elementary bodies (EBs) are released from host cells, MAP1 appears to be organized in SDS and heat-resistant dimers and trimers stabilized by disulfide bridges. Overall, the results presented herein not only reveal the first partial proteome map of ER but provide new insights on the expression ER MAP1-family proteins in host endothelial cells.     

QTL mapping and identification of corresponding genomic regions for black pod disease resistance to three <Emphasis Type="Italic">Phytophthora</Emphasis> species in <Emphasis Type="Italic">Theobroma cacao</Emphasis> L.

The cacao tree (Theobroma cacao L.) is a species of great importance because cacao beans are the raw material used in the production of chocolate. However, the economic success of cacao is largely limited by important diseases such as black pod, which is responsible for losses of up to 30–40% of the global cacao harvest. The discovery of resistance genes could extensively reduce these losses. Therefore, the aims of this study were to construct an integrated multipoint genetic map, align polymorphisms against the available cacao genome, and identify quantitative trait loci (QTLs) associated with resistance to black pod disease in cacao. The genetic map had a total length of 956.41 cM and included 186 simple sequence repeat (SSR) markers distributed among 10 linkage groups. The physical “in silico” map covered more than 200 Mb of the cacao genome. Based on the mixed model predicted means of Phytophthora evaluation, a total of 6 QTLs were detected for Phytophthora palmivora (1 QTL), Phytophthora citrophthora (1 QTL), and Phytophthora capsici (4 QTLs). Approximately 1.77–3.29% of the phenotypic variation could be explained by the mapped QTLs. Several SSR marker-flanking regions containing mapped QTLs were located in proximity to disease regions. The greatest number of resistance genes was detected in linkage group 6, which provides strong evidence for a QTL. This joint analysis involving multipoint and mixed-model approaches may provide a potentially promising technique for detecting genes resistant to black pod and could be very useful for future studies in cacao breeding.     

Past land-use and ecological resilience in a lowland Brazilian Atlantic Forest: implications for passive restoration

The ecological resilience of abandoned pastures has important implications for the potential of passive restoration in the Brazilian Atlantic Forest, especially in the face of the ambitious restoration targets for this biodiversity hotspot. In the present study, we aimed to investigate the influence of past land-use on natural regeneration in two secondary forests that established on abandoned pastures with different land use histories (Abandoned + Fire—15 years since the last fire event and Abandoned—36 years ago) in a lowland Brazilian Atlantic Forest. Both secondary forests exhibit low resilience for the three analyzed attributes: vegetation structure, richness, and species composition. Secondary forests affected by fire have the lowest values for species richness, aboveground biomass and leaf area index compared to old-growth forests. Secondary forests were dominated by Moquiniastrum polymorphum—Asteraceae, which was absent from the old-growth forests. Fire resistance, capacity to establish in nutrient-poor soils and efficient seed dispersal in human-modified landscapes are important attributes that may explain the dominance of this species. We demonstrate that even in sites considered appropriate for passive restoration a priori (e.g. located in a protected area, 36 years since abandonment and close to old-growth forests), secondary forests exhibited low aboveground biomass and communities were dominated by few species. Therefore, our results highlight the effects of past land-use on natural regeneration and suggest the necessity to use interventions such as enrichment plantings, nucleation techniques and assisted natural regeneration in order to accelerate forest restoration.     

Luteal activity and effect of dietary energy restriction on follicular development in lactating cows

The aim of this research has been to evaluate the presence of anomalies in the ovarian cycle activity during postpartum and to verify whether 72‐hr dietary fasting during the dominance phase, the phase before ovulation, might modify the ovarian follicle population. The presence of anomalies in ovarian cycle activity has been evaluated in 30 Italian Friesian cows starting from 20 days postpartum until 211 days of lactation. Long oestrus and brief dioestrus or scarce luteal activity have been the main anomalies found through measuring progesterone concentrations in the whey. Until 100 days of lactation, the BCS values of the problematic animals have been significantly lower than those in animals with normal ovarian activity. After 100 days of lactation, the ovarian anomalies continued to appear despite the fact that all the animals have reached comparable BCS values. Starting from the results of this trial, the effect of 72‐hr dietary fasting on dominant follicles has been studied in six cows. Ultrasonography revealed that the diameter of the follicles at 71 days postpartum has been significantly lower than at 181 days. A 72‐hr dietary restriction at 101 and 211 days postpartum did not affect the size of the dominant follicle. However, at 101 days postpartum, half of the animals presented follicular cysts. The effect of fasting differed if the animal has been in early postpartum or 211 days of lactation. Further researches are necessary to understand how different metabolic conditions can modify the follicular population but on the other hand the study shows the utility for farmers and field veterinarians of monitoring the resumption of the ovarian cycle postpartum through the whey progesterone concentrations.     

Flow cytometry in Spermatology: A bright future ahead

Techniques such as mass spectrometry have led to unprecedented knowledge of the proteins that are present in the spermatozoa of humans and other mammals. However, in spite of their high‐throughput and fractioning techniques, most of the techniques in use only offer average values for the entire sperm population. Yet, ejaculate is very heterogeneous, and average values may mask relevant biological information.The application of flow cytometry may overcome this disadvantage, allowing proteomic analysis at the single‐cell level. Moreover, recent advances in cytometry, allowing multiple analyses within a single cell combined with powerful statistical tools, as an expanding subfield in spermatology, are described. The increased use of advanced flow cytometers in andrology laboratories will allow the rapid development of multiparametric, multicolour flow cytometry in andrology that will expand the clinical applications and research possibilities of flow cytometry‐based proteomic approaches, especially in the subfields of clinical andrology and sperm biotechnology.     

Characterization and quantitation of polyphenolic compounds in bark, kernel, leaves, and peel of mango (Mangifera indica L.)

The contents of secondary plant substances in solvent extracts of various byproducts (barks, kernels, peels, and old and young leaves) in a range of Brazilian mango cultivars were identified and quantitated. The results show that the profiles of secondary plant substances such as xanthone C-glycosides, gallotannins, and benzophenones in different byproducts vary greatly but are fairly consistent across cultivars. The free radical scavenging activity of the solvent extracts was evaluated using a high-performance liquid chromatography-based hypoxanthine/xanthine oxidase assay and revealed dose-dependent antioxidant capacity in all extracts. Four (mangiferin, penta- O-galloyl-glucoside gallic acid, and methyl gallate) of the major phenolic compounds detected were also evaluated in additional in vitro bioassay systems such as oxygen radical absorbance capacity, 2,2-diphenyl-1-picrylhydrazyl, and ferric reducing ability of plasma. Mangiferin in particular, detected at high concentrations in young leaves (Coite = 172 g/kg), in bark (Momika = 107 g/kg), and in old leaves (Itamaraka = 94 g/kg), shows an exceptionally strong antioxidant capacity.