Intravaginal progesterone device and/or temporary weaning on reproductive performance of anestrous crossbred Angus x Nelore cows

The objective of this experiment was to evaluate effects of treatments with intravaginal progesterone (P4) device and/or 48h temporary weaning (TW) on reproductive performance of postpartum anestrous crossbred AngusxNelore cows, throughout the breeding season (BS). Anestrous cows (n=286; 53+/-5 DPP, body condition score between 2.5 and 3.5, on a 1-5 scale) were assigned randomly to four treatments (2x2 factorial design): (1) Control Group (no treatment; n=73); (2) TW Group (48h TW beginning on day 0 of BS; n=70); (3) P4 Group (Intravaginal P4 device between days -7 and 0 of BS; n=73); and (4) P4+TW Group (Intravaginal P4 device between days -7 and 0 of BS followed by 48h TW; n=70). On day 0 of BS (when P4 devices were removed and TW was initiated), cows had their ovaries evaluated by ultrasonography aiming to evaluate size of the largest follicle. Signs of behavioral estrus were observed twice a day (morning and evening), between days 0 and 25 of BS, and cows observed in estrus were inseminated 12h later. Between days 26 and 80 of BS, cows were submitted to natural service. Pregnancy diagnosis was conducted by transrectal ultrasonography on days 32 and 53 (pregnancies by AI) and 114 (pregnancies by natural service). Rates of detection of estrus during the first 3 days and within 25 days of BS were greater in cows receiving TW (45.0% compared with 9.6% and 50.0% compared with 29.5%, respectively; P<0.01). Conception rate in cows inseminated in the first 3 days of BS was greater in cows treated with P4 (54.8% compared with 11.1%; P<0.01). Combining P4+TW increased pregnancy rate in the first 3 days (Control: 1.4%, TW: 4.3%, P4: 8.2% and P4+TW: 24.3%; P<0.01) and in 25 days of BS (Control: 10.9%, TW: 7.1%, P4: 13.7% and P4+TW: 28.6%; P<0.05). Pregnancy rate at the end of BS did not differ among treatment groups. In conclusion, TW alone increased estrous behavior whereas P4 alone benefited conception. Combining P4 with TW improved pregnancy rate with direct benefits to behavioral estrus and conception.     

Callus,shoot and hairy root formation in vitro as affected by the sensitivity to auxin and ethylene in tomato mutants

We analyzed the impact of ethylene and auxin disturbances on callus, shoots and Agrobacterium rhizogenes-induced hairy root formation in tomato (Solanum lycopersicum L.). The auxin low-sensitivity dgt mutation showed little hairy root initiation, whereas the ethylene low-sensitivity Nr mutation did not differ from the control Micro-Tom cultivar. Micro-Tom and dgt hairy roots containing auxin sensitivity/biosynthesis rol and aux genes formed prominent callus onto media supplemented with cytokinin. Under the same conditions, Nr hairy roots did not form callus. Double mutants combining Rg1, a mutation conferring elevated shoot formation capacity, with either dgt or Nr produced explants that formed shoots with little callus proliferation. The presence of rol + aux genes in Rg1 hairy roots prevented shoot formation. Taken together, the results suggest that although ethylene does not affect hairy root induction, as auxin does, it may be necessary for auxin-induced callus formation in tomato. Moreover, excess auxin prevents shoot formation in Rg1.     

Bevacizumab and ranibizumab on microvascular endothelial cells: A comparative study

Given its broad effects in endothelium, vascular endothelial growth factor (VEGF) represents the primary rate‐limiting step of angiogenesis. Therefore, VEGF targeting therapies were soon developed. Bevacizumab and ranibizumab are two of these therapeutic agents already in clinical use. Bevacizumab was first used for cancer treatment, whereas ranibizumab was designed to target choroidal neovascularization, the main cause of blindness in age‐related macular degeneration. The present study aims to compare the multiple effects of bevacizumab and ranibizumab in human microvascular endothelial cells (HMECs). HMEC cultures were established and treated during 24 h with the anti‐VEGF agents within the intravitreal‐established concentration range or excipients. Analyses of VEGF content in cell media and VEGF receptor‐2 (VEGFR‐2) expression in cell lysates were performed. No cell cytotoxicity (MTS assay) was found in anti‐VEGF‐treated cultures at any concentration. Apoptosis (TUNEL assay) was significantly increased and cell proliferation (BrdU assay), migration (transwell assay) and assembly into vascular structures were significantly reduced by incubation with both agents at the two doses used. These findings were accompanied by a strong decrease in VEGF release, and in phosphorylated VEGFR‐2 and Akt expression for both agents at the clinical concentration. Interestingly, phosphorylated Erk was only significantly reduced upon bevacizumab treatment. In addition, proliferation was more affected by ranibizumab, whereas migration, capillary formation, and phosphorylated VEGFR2 expression were significantly reduced by bevacizumab as compared to ranibizumab. Therefore, although both agents presented anti‐angiogenic actions, distinct effects were exerted by the two molecules in HMEC. These findings suggest that a careful confirmation of these effects in clinical settings is mandatory. J. Cell. Biochem. 108: 1410–1417, 2009. © 2009 Wiley‐Liss, Inc.     

Interaction between the CBM of Cel9A from Thermobifida fusca and cellulose fibers

Molecular docking and molecular dynamics (MD) simulations were used to investigate the binding of a cellodextrin chain in a crystal-like conformation to the carbohydrate-binding module (CBM) of Cel9A from Thermobifida fusca. The fiber was found to bind to the CBM in a single and well-defined configuration in-line with the catalytic cleft, supporting the hypothesis that this CBM plays a role in the catalysis by feeding the catalytic domain (CD) with a polysaccharide chain. The results also expand the current known list of residues involved in the binding. The polysaccharide-protein attachment is shown to be mediated by five amine/amide-containing residues. E478 and E559 were found not to interact directly with the sugar chain; instead they seem to be responsible to stabilize the binding motif via hydrogen bonds.     

Hexahedral modular bioreactor for solid state bioprocesses

The design of a modular bioreactor for solid state fermentation is a promising development because it keeps the homogeneity of the bed at optimal levels. This study determines the optimum geometry of elementary modules of hexahedral bioreactors subjected to constant volume. The bioreactors have a square section and do not need an external cooling system, because the optimization limits the temperature of the bed to 35°C. The geometric optimization followed the Constructal principle of minimum heat resistance. The numerical simulations take into account the following parameters: inlet air temperature and velocity, and module volume. Once the elementary module has been selected, the total volume of the bioreactor can be calculated.     

Assessment of physiological conditions in E. coli fermentations by epifluorescent microscopy and image analysis

The development of monitoring methods for assessing the physiological state of microorganisms during recombinant fermentation processes has been encouraged by the need to evaluate the influence of processing conditions in recombinant protein production. In this work, a technique based on microscopy and image analysis was developed that allows the simultaneous quantification of parameters associated with viability and fluorescent protein production in recombinant Escherichia coli fermentations. Images obtained from light microscopy with phase contrast are used to assess the total number of cells in a given sample and, from epifluorescence microscopy, both protein producing and injured cells are evaluated using two different fluorochromes: propidium iodide and enhanced yellow fluorescent protein. This technique revealed the existence of different cell populations in the recombinant E. coli fermentation broth that were evaluated along four batch fermentations, complementing information obtained with standard techniques to study the effects of the temperature and induction time in recombinant protein production processes. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

Interaction of lipid bodies with other cell organelles in the maturing pollen of Magnolia × soulangeana (Magnoliaceae)

The pollen grain maturation in Magnolia × soulangeana was studied ultrastructurally and cytochemically using both the light and transmission electron microscope. Emphasis was given on the storage lipid bodies of the vegetative cell (VC) and their interaction with other cell organelles. Stereological analysis of electron micrographs was performed to evaluate the variation in volume density (V_V), surface density, and surface-to-volume ratio (S/V) of various cell organelles during pollen maturation. The size and numerical density of the lipid bodies, and their frequency of association with other cell organelles, were also determined. It was noted that during pollen ontogeny and maturation, the lipid bodies changed their pattern of distribution in the VC cytoplasm, which may be a good marker for the succeeding stages of pollen development. Also, the size, osmiophily, and V_V of the lipid bodies were progressively reduced during pollen maturation whereas the S/V was significantly increased. This seems to indicate that the lipid bodies are mobilized in part during this period of pollen maturation. In particular, the intermediate and mature pollen showed a high percentage of lipid bodies establishing a physical contact with either glyoxysomes, either protein storage vacuoles, or small vesicles presumably originated from dictyosomes. This physical contact was found in both the chemically fixed and rapid freeze-fixed pollen indicating that it is neither artifactual nor casual. On the basis of this intimate association with other cell organelles and the morphometric analysis performed, we suggest that the mobilization of lipid bodies is likely mediated not only by glyoxysomes but also by other catabolic pathways involving the interaction of lipid bodies with either protein storage vacuoles or small Golgi vesicles.     

The Role of Spatial Refuges in Coupled Map Lattice Model for Host-Parasitoid Systems

A Coupled Map Lattice (CML) model, for host-parasitoid Nicholson–Bailey interactions, with an explicit spatial distribution of partial refuge areas, is presented by considering the parasitoid attack rate as a patch dependent parameter. The effect of habitat heterogeneity on the dynamics of both populations, that is, on their spatial distribution and temporal behavior is analyzed. Our results show that depending on many features such as position, size, and fragmentation of a refuge, as well as the dispersal parameters of hosts and parasitoids, together with the parasitoid attack rate, the inclusion of refuges may as well stabilize as destabilize the host-parasitoid dynamics. The results are analyzed for the local and the global scales. Spatial patterns resulting from such heterogeneous patchy environments are also obtained.     

Myzobdella platensis (Hirundinida: Piscicolidae) is true parasite of blue crabs (Crustacea: Portunidae)

Leeches exhibit a marked scope of diversity, including different kinds of symbiosis. The aim of the present study was to demonstrate through biochemical and histological analysis that a species of piscicolid leech, Myzobdella platensis, is a true parasite of blue crabs, feeding on their hemolymph and using them as a site for cocoon deposition. In a total of 48 blue crabs collected on October 2007 at 3 sites of the S?o Vicente Estuary, 12 specimens were infested with leeches. Callinectes bocourti (n = 7) was the most infested species with leeches and cocoons; it was chosen for biochemical and histological assays. The immunoblotting assays showed a positive reaction of the proteins in the intestinal samples of leeches collected from crabs using antihemocyanin polyclonal antibody of Ampullaria canaliculata. In addition, leech intestinal samples were recognized by antihemolymph polyclonal antibody of nonparasitized blue crabs. Histological sections of leech gut showed hemocytes and a granular matrix similar to those found in crab blood vessels. Collectively, this evidence strongly suggests a parasitic interaction between the leech M. platensis and the blue crab C. bocourti, in which the former utilizes the latter as a site for cocoon deposition and possibly for dispersal similar to that proposed for Myzobdella lugubris in Callinectes sapidus in North America.     

The role of sexually abstained groups in two-sex demographic and epidemic logistic models with non-linear mortality

We describe several gender structured population models governed by logistic growth with non-linear death rate. We extend these models to include groups of people isolated from sexual activity and individuals exposed to a mild and long-lasting sexually transmitted disease, i.e. without disease-induced mortality and recovery. The transmission of the disease is modeled through formation/separation of heterosexual couples assuming that one infected individual automatically infects his/her partner. We are interested in how the non-reproductive class may change the demographic tendencies in the general population and whether they can curb the growth of the infected group while keeping the healthy one at acceptable levels. A comparison of the equilibrium total population size in the presence and the absence of the isolated class is also provided.