Ovulation rate and its relationship with follicle diameter and gene expression of the LH receptor (LHR) in Nelore cows

The objective was to determine the relationship among the diameter of ovarian follicles, ovulation rate, and gene expression of the LH receptor (LHR) in Nelore cattle. In Experiment 1, ovulation was synchronized in 53 Nelore cows. Three days after ovulation, ovaries were assessed with ultrasonography, all cows were given 6.25 mg LH im, and they were allocated into three groups, according to diameter of their largest ovarian follicle: G1 (7.0-8.0 mm); G2 (8.1-9.0 mm); and G3 (9.1-10.0 mm). For these three groups, ovulation rates were 9, 36, and 90%, respectively, (P <0.03; each rate differed significantly from the other two). In Experiment 2, granulosa and theca cells were subjected to total RNA extraction, and gene expression of the LHR was determined by RT-PCR. Follicles were allocated in three groups based on their diameter (similar to the Experiment 1), which were denoted Groups A, B, and C. Expression of the LHR gene in granulosa cells was lower in Group A than Group C (P < 0.05). However, there were no significant differences among groups in expression of the LHR gene in theca cells. We concluded that ovulatory capacity in Nelore cattle was related to increased follicular diameter and expression of the LHR gene in granulosa cells.     

Synovial cytokine expression in psoriatic arthritis and associations with lymphoid neogenesis and clinical features

Demonstration of an association between inflammation and spinal ankylosis has been challenging. Until the advent of MRI, prospective study was not possible due to inaccessibility of tissue. Recent studies using MRI have described an association between the presence of bone edema at vertebral corners on MRI and the subsequent development of syndesmophytes at the corresponding vertebral corners on radiography. Although reports have also highlighted the development of new syndesmophytes where the baseline MRI shows no inflammation, MRI has limited sensitivity for detection of spinal inflammation that is clearly evident on histopathology. There are also crucial methodological challenges because radiographic assessment is limited to the anterior corners of the cervical and lumbar spine while MRI lesions in the cervical spine are often small while spurious inflammatory signal is common in the lumbar spine. Follow-up MRI evaluation in two independent studies has also shown that inflammatory lesions that resolve after anti-TNF therapy are more prone to develop into syndesmophytes. It may be possible that very early inflammatory lesions resolve completely without sequelae if anti-TNF therapy is introduced before new bone formation becomes largely autonomous. For an individual patient the overall development of new bone during anti-TNF therapy may therefore depend on the balance between the number of early and more mature inflammatory lesions. Clinical trials of anti-TNF agents in early spondyloarthritis together with prospective MRI studies will allow more detailed testing of this hypothesis as a major priority for the research agenda in spondyloarthritis.     

Assortative mating among Lake Malawi cichlid fish populations is not simply predictable from male nuptial colour

Background  

Research on the evolution of reproductive isolation in African cichlid fishes has largely focussed on the role of male colours and female mate choice. Here, we tested predictions from the hypothesis that allopatric divergence in male colour is associated with corresponding divergence in preference.     

Phylogeography and local endemism of the native Mediterranean brine shrimp Artemia salina (Branchiopoda: Anostraca)

There has been a recent appreciation of the ecological impacts of zooplanktonic species invasions. The North American brine shrimp Artemia franciscana is one such alien invader in hyper-saline water ecosystems at a global scale. It has been shown to outcompete native Artemia species, leading to their local extinction. We used partial sequences of the mitochondrial Cytochrome c Oxidase Subunit 1 (COI or cox1) gene to investigate the genetic diversity and phylogeography of A. salina, an extreme halophilic sexual brine shrimp, over its known distribution range (Mediterranean Basin and South Africa) and to assess the extent of local endemism, the degree of population structure and the potential impact of traditional human saltpan management on this species. We also examined the phylogenetic relationships in the genus Artemia using COI sequences. Our results show extensive regional endemism and indicate an early Pleistocene expansion of A. salina in the Mediterranean Basin. Subsequent population isolation in a mosaic of Pleistocene refugia is suggested, with two or three refugia located in the Iberian Peninsula. Two instances of long-distance colonization were also observed. Surprisingly, given its strong phylogeographical structure, A. salina showed a signature of correlation between geographical and genetic distance. Owing to strong 'priority effects', extensive population differentiation is retained, despite dispersal via migrant birds and human management of saltpans. The foreseeable expansion of A. franciscana is likely to be followed by substantial loss of genetic diversity in Mediterranean A. salina. Large genetic divergences between Mediterranean and South African A. salina suggest that the latter deserves species status.     

The margination propensity of spherical particles for vascular targeting in the microcirculation

The propensity of circulating particles to drift laterally towards the vessel walls (margination) in the microcirculation has been experimentally studied using a parallel plate flow chamber. Fluorescent polystyrene particles, with a relative density to water of just 50 g/cm ³comparable with that of liposomal or polymeric nanoparticles used in drug delivery and bio-imaging, have been used with a diameter spanning over three order of magnitudes from 50 nm up to 10 μm. The number of particles marginating per unit surface have been measured through confocal fluorescent microscopy for a horizontal chamber, and the corresponding total volume of particles has been calculated. Scaling laws have been derived as a function of the particle diameter d. In horizontal capillaries, margination is mainly due to the gravitational force for particles with d > 200 nm and increases with d ⁴; whereas for smaller particles increases with d ³. In vertical capillaries, since the particles are heavier than the fluid they would tend to marginate towards the walls in downward flows and towards the center in upward flows, with increasing with d ^9/2. However, the margination in vertical capillaries is predicted to be much smaller than in horizontal capillaries. These results suggest that, for particles circulating in an external field of volume forces (gravitation or magnetic), the strategy of using larger particles designed to marginate and adhere firmly to the vascular walls under flow could be more effective than that of using particles sufficiently small (d < 200 nm) to hopefully cross a discontinuous endothelium.     

A new mouse model of Peyronie's disease: an increased expression of hypoxia-inducible factor-1 target genes during the development of penile changes

Peyronie's disease (PD) is characterized by an inflammatory response beneath the tunica albuginea with fibroblast proliferation forming a thickened fibrous plaque that may cause pain, penile curvature and erectile dysfunction. The progression of the PD plaque may eventually lead to calcification or ossification. Current therapeutic success is often unsatisfactory because of limited insight into disease mechanisms. Research has been hampered by the lack of a universally accepted animal model. We describe an animal model of spontaneous PD in tight skin (Tsk) mice, a C57Bl/6J subline that reproduces with age important features of the human disease (fibrous plaque formation, penile bending and areas of chondroid metaplasia with heterotopic ossification). Histological analysis demonstrated an evident structural disorganization of the tunica albuginea with excessive accumulation of type I collagen. At 12 months of age, fibrous plaques with areas of chondroid metaplasia and heterotopic ossification characterized Tsk penises. The up-regulation of hypoxia-inducible factor-1 (HIF-1) leads to an increased downstream expression of HIF-1 target genes, such as TGFbeta and iNOS. These factors, together with some PDGF family members, can cause collagen deposition in Tsk penises. They can also influence chondrocyte differentiation and heterotopic bone formation. In conclusion, hypoxia, HIF-1 and HIF-1 target genes appear to play an important role in the pathogenesis of PD in Tsk mice. This mouse model that is the first example of naturally occurring model of PD in laboratory animals may aid in the identification of signalling pathways crucial for PD and should facilitate the designing and testing of new therapeutic interventions.     

Akt Regulates Drug-Induced Cell Death through Bcl-w Downregulation

Akt is a serine threonine kinase with a major role in transducing survival signals and regulating proteins involved in apoptosis. To find new interactors of Akt involved in cell survival, we performed a two-hybrid screening in yeast using human full-length Akt c-DNA as bait and a murine c-DNA library as prey. Among the 80 clones obtained, two were identified as Bcl-w. Bcl-w is a member of the Bcl-2 family that is essential for the regulation of cellular survival, and that is up-regulated in different human tumors, such as gastric and colorectal carcinomas. Direct interaction of Bcl-w with Akt was confirmed by immunoprecipitation assays. Subsequently, we addressed the function of this interaction: by interfering with the activity or amount of Akt, we have demonstrated that Akt modulates the amount of Bcl-w protein. We have found that inhibition of Akt activity may promote apoptosis through the downregulation of Bcl-w protein and the consequential reduction in interaction of Bcl-w with pro-apoptotic members of the Bcl-2 family. Our data provide evidence that Bcl-w is a new member of the Akt pathway and that Akt may induce anti-apoptotic signals at least in part through the regulation of the amount and activity of Bcl-w.     

High lipids accumulation in <Emphasis Type="Italic">Rhodosporidium toruloides</Emphasis> by applying single and multiple nutrients limitation in a simple chemically defined medium

Microbial oil produced by the oleaginous yeast Rhodosporidium toruloides ATCC 204091 (formerly referred to as Rhodotorula glutinis) has a similar fatty acid composition to the vegetable oils and represents a potential alternative for biodiesel production. Finding strategies to improve the oil production by this yeast is desirable, as it is one of this nutrient’s limitations during the accumulation phase, as well as one of the main factors influencing the process. Therefore, the effect of single or combined nutrient limitation on lipid accumulation by R. toruloides was investigated. Biomass production and lipid accumulation by R. toruloides was improved using experimental designs in a two-step batch culture on a chemically-defined culture medium with high initial glucose concentration. For the first culture step, a Box–Behnken design was applied to optimize the main medium components’ concentrations, while maintaining a high biomass production. A biomass concentration of 44.3 g/L was reached with a medium composed of (g/L): glucose, 100; KH₂PO₄, 4.6; NaNO₃, 13.4; MgSO₄ ^.7H₂O, 0.2; and CaCl₂ ^.2H₂O, 0.11. For the second culture step, the biomass was transferred to lipid accumulation media. A 2³ factorial experimental design was conducted to investigate the effect of N, P and S limitations (individually or jointly) on lipid production from glucose (100 g/L). Lipid accumulation on dry cell mass was 77.04, 65.42, 70.13 and 69.84% for N, P, S and simultaneous nutrients’ limitations, respectively.     

Nitro-substituted tetrahydroindolizines and homologs: Design,kinetics, and mechanism of α-glucosidase inhibition

A series of 1-[(methylsulfonyl)methyl]-2-nitro-5,6,7,8-tetrahydroindolizines and homologs were designed, prepared, and evaluated as non-sugar-type α-glucosidase inhibitors. The inhibitory activity appeared to be related to cyclo homologation with the best congeners being tetrahydroindolizines. The introduction of a methoxycarbonyl group as an additional hydrogen bond acceptor into the exocyclic methylene group was beneficial affording the most potent congener 3e (half maximal inhibitory concentration, IC₅₀ = 8.0 ± 0.1 μM) which displayed 25-fold higher inhibitory activity than 1-deoxynojirimycin (2, IC₅₀ = 203 ± 9 μM)—the reference compound. Kinetic analysis indicated that compound 3e is a mixed inhibitor with preference for the free enzyme over the α-glucosidase–substrate complex (K_i,free = 3.6 μM; K_i,bound = 7.6 μM). Molecular docking experiments were in agreement with kinetic results indicating reliable interactions with both the catalytic cleft and other sites. Circular dichroism spectroscopy studies suggested that the inhibition exerted by 3e may involve changes in the secondary structure of the enzyme. Considering the relatively low molecular weight of 3e together with its high fraction of sp³ hybridized carbon atoms, this nitro-substituted tetrahydroindolizine may be considered as a good starting point towards new leads in the area of α-glucosidase inhibitors.