Metastatic bladder cancer cells distinctively sense and respond to physical cues of collagen fibril-mimetic nanotopography

Tumor metastasis is characterized by enhanced invasiveness and migration of tumor cells through the extracellular matrix (ECM), resulting in extravasation into the blood and lymph and colonization at secondary sites. The ECM provides a physical scaffold consisting of components such as collagen fibrils, which have distinct dimensions at the nanoscale. In addition to the interaction of peptide moieties with tumor cell integrin clusters, the ECM provides a physical guide for tumor cell migration. Using nanolithography we set out to mimic the physical dimensions of collagen fibrils using lined nanotopographical silicon surfaces and to explore whether metastatic tumor cells are uniquely able to respond to these physical dimensions. Etched silicon surfaces containing nanoscale lined patterns with varying trench and ridge sizes (65–500 nm) were evaluated for their ability to distinguish between a non-metastatic (253J) and a highly metastatic (253J-BV) derivative bladder cancer cell line. Enhanced alignment was distinctively observed for the metastatic cell lines on feature sizes that mimic the dimensions of collagen fibrils (65–100 nm lines, 1:1–1:1.5 pitch). Further, these sub-100 nm lines acted as guides for migration of metastatic cancer cells. Interestingly, even at this subcellular scale, metastatic cell migration was abrogated when cells were forced to move perpendicular to these lines. Compared to flat surfaces, 65 nm lines enhanced the formation of actin stress fibers and filopodia of metastatic cells. This was accompanied by increased formation of focal contacts, visualized by immunofluorescent staining of phospho-focal adhesion kinase along the protruding lamellipodia. Simple lined nanotopography appears to be an informative platform for studying the physical cues of the ECM in a pseudo-3D format and likely mimics physical aspects of collagen fibrils. Metastatic cancer cells appear distinctively well adapted to sense these features using filopodia protrusions to enhance their alignment and migration.     

Freeze fracture studies on the interaction between the malaria parasite and the host erythrocyte in Plasmodium knowlesi infections.

The freeze fracture technique has been used to study the internal cyto-architecture of the surface membranes of the parasite and erythrocyte in Plasmodium knowlesi infections. Six fracture faces, derived from the plasma membrane and 2 pellicular membranes, have been identified at the surface of the free merozoite. The apposed leaflets of the 2 pellicular membranes show the characteristic features of E fracture faces, a result compatible with the view that the pellicular membranes line a potential cisterna. There is evidence to suggest that there may be changes in the distribution and density of the integral proteins in the merozoite plasma membrane at invasion. Furthermore, vesicles consisting of stacked membranes occur within and around the erythrocyte invagination at invasion; it is suggested that these vesicles are released from the merozoite rhoptries. Formation of the parasitophorous vacuole is accompanied by dramatic changes in the density and distribution of intra-membraneous particles (IMP) in the vacuolar membrane. Initially there is a great reduction in particle numbers, but subsequently the particles reappear and show reversed polarity. The possible causes and implications of these changes are discussed. The intra-erythrocytic parasite synthesizes new transmembrane proteins as development proceeds, and the trophozoite and schizont stages of development are characterized by the appearance of circular, particle-free regions in the parasite plasmalemma. There is a decrease in the density of transmembrane proteins in the erythrocyte plasma membrane during parasite maturation, and the P face IMP show the characteristic features of aggregation.     

Superstimulation of ovarian follicular growth with FSH oocyte recovery, and embryo production from Zebu (Bos indicus) calves: effects of treatment with a GnRH agonist or antagonist

The capacity of heifer calves of a late sexually maturing Zebu (Bos indicus) genotype to respond to superstimulation with FSH at a young age and in vitro oocyte development were examined. Some calves were treated with a GnRH agonist (deslorelin) or antagonist (cetrorelix) to determine whether altering plasma concentrations of LH would influence follicular responses to FSH and oocyte developmental competency. Brahman calves (3-mo-old; 140 +/- 3 kg) were randomly assigned to 3 groups: control (n = 10); deslorelin treatment from Day -8 to 3 (n = 10); and cetrorelix treatment from Day -3 to 2 (n = 10). All calves were stimulated with FSH from Day 0 to 2, and were ovariectomized on Day 3 to determine follicular responses to FSH and to recover oocytes for in vitro procedures. Before treatment with FSH, heifers receiving deslorelin had greater (P < 0.001) plasma LH (0.30 +/- 0.01 ng/ml) than control heifers (0.17 +/- 0.02 ng/ml), while plasma LH was reduced (P < 0.05) in heifers treated with cetrorelix (0.13 +/- 0.01 ng/ml). Control heifers had a surge release of LH during treatment with FSH, but this did not occur in heifers treated with deslorelin or cetrorelix. All heifers had large numbers of follicles > or = 2 mm (approximately 60 follicles) after superstimulation with FSH, and there were no differences (P > 0.10) between groups. Total numbers of oocytes recovered and cultured also did not differ (P > 0.05) for control heifers and heifers treated with deslorelin or cetrorelix. Fertilization and cleavage rates were similar for the 3 groups, and developmental rates to blastocysts were also similar. Zebu heifers respond well to superstimulation with FSH at a young age, and their oocytes are developmentally competent.     

Applications of GnRH in the control and management of fertility in female animals

Gonadotropin releasing hormone (GnRH) has long been recognized as a potential target for the control and management of fertility in female animals. Attempts to apply GnRH-based technology to manage fertility have focussed on the development of GnRH agonists, antagonists and vaccines. All of these methods have potential, but the widespread application of these technologies has been limited to date. The greatest advance in the use of GnRH-based technology for long-term fertility control in recent years has been the development and commercialization of depot formulations that release GnRH agonists for periods of up to 1 year. These products have a broad range of potential applications in production and domestic animal management. The further development and commercialization of GnRH vaccines has been hampered by the variability of response between individual animals. The need to use adjuvant and multiple boosters also make this a less attractive option than the current GnRH agonist technology. However, GnRH vaccines have the advantage that they do not induce the initial stimulatory response that follows GnRH agonist administration. GnRH antagonists and GnRH-toxin conjugates show promise but are in an earlier phase of development. To date, no depot or long-acting formulations of antagonists have been developed. GnRH-toxin conjugates have yet to achieve permanent sterilization, but further dose-response trials may advance this approach.     

Inbreeding depression and genetic load of sexually selected traits: how the guppy lost its spots

To date, few studies have investigated the effects of inbreeding on sexually selected traits, although inbreeding depression on such traits can play an important role in the evolution and ecology of wild populations. Sexually selected traits such as ornamentation and courtship behaviour may not be primary fitness characters, but selection and dominance coefficients of their mutations will resemble those of traits under natural selection. Strong directional selection, for instance, through female mate-choice, purges all but the most recessive deleterious mutations, and the remaining dominance variation will result in inbreeding depression once populations undergo bottlenecks. We analysed the effects of inbreeding on sexually selected traits (colour pattern and courtship behaviour) in the male guppy, Poecilia reticulata, from Trinidad, and found a significant decline in the frequency of mating behaviour and colour spots. Such effects occurred although the genetic basis of these traits, many of which are Y-linked and hemizygous, would be expected to leave relatively little scope for inbreeding depression. Findings suggest that these sexually selected traits could reflect the genetic condition or health of males, and thus may be informative mate-cue characters for female choice as suggested by the 'good genes' model.     

Data mining in bioinformatics using Weka

The Weka machine learning workbench provides a general-purpose environment for automatic classification, regression, clustering and feature selection-common data mining problems in bioinformatics research. It contains an extensive collection of machine learning algorithms and data pre-processing methods complemented by graphical user interfaces for data exploration and the experimental comparison of different machine learning techniques on the same problem. Weka can process data given in the form of a single relational table. Its main objectives are to (a) assist users in extracting useful information from data and (b) enable them to easily identify a suitable algorithm for generating an accurate predictive model from it. AVAILABILITY: http://www.cs.waikato.ac.nz/ml/weka.     

Sustained testicular atrophy in bulls actively immunized against GnRH: potential to control carcase characteristics

The objectives were to determine whether active immunization against gonadotrophin releasing hormone (GnRH) induced a long-term suppression of testicular function in bulls, and to ascertain the effects of immunization against GnRH on carcase and meat quality characteristics. In experiment 1, 6-month-old Zebu bulls were assigned to: control (n=25), no treatment; immunized (n=31), immunized against GnRH at 0 and 4 months (anti-GnRH(2)), with a sub-set of bulls (n=17) immunized again at 10 months (anti-GnRH(3)). After the second immunization, testicular growth ceased for 2 months in 14/31 (45%) bulls and for at least 6 months in 17/31 (55%) bulls. Among the latter bulls (anti-GnRH(3)) the testes did not grow for >1 year after the third immunization in 5/17 (30%) bulls. In experiment 2, 22-month-old Zebu bulls were assigned to: control (n=14), no treatment; immunized (n=17), immunized against GnRH at 0, 2 and 4 weeks. The testes decreased (P<0.05) in size for 2 months after immunization in 11/17 (65%) bulls and then re-initiated growth, whilst in 6/17 (35%) bulls the testes continued to decrease in size for 4 months and did not re-initiate growth for 1 year. At slaughter, the latter immunocastrated bulls had carcase and meat quality characteristics the same as contemporary bulls that had been castrated before puberty. The findings demonstrated that active immunization against GnRH can induce a long-term suppression of testicular function in a proportion of bulls. Also, when bulls are immunocastrated after puberty, carcase and meat quality traits change from those typical of entire bulls to traits that are characteristic of long-term castrated bulls.     

Hair growth in mouse mutants affecting coat texture

The genetic control of hair growth has been studied in mice carrying the following coat texture genes: fz (fuzzy), soc (soft coat), hid (hair interior defect), sa (satin), It (lustrous), Ve (velvet), wa-1 (waved-1), Re (rex), Re ^wc (wavy coat) and pk (plucked).
A general effect on cells of epidermal origin, found in soc/soc and Ve /+ skin samples illustrates how common factors control developmental potential in both the stratum germinativum and the follicle bulb. A direct influence on follicle bulb development is also seen in fz/fz homozygotes in which the dermal papilla functions abnormally. The role of the bulb cells and the dermal papilla in the control of hair shaft calibre is discussed.
hid is a new gene, found in homozygous condition in all mice of the AKR inbred strain. hid and sa appear primarily to be concerned in the differentiation of the medulla.
In the hair waving mutants, waved-1, rex and wavy coat, the processes controlling hair movement within the follicle are disturbed. These genes appear to regulate internal root sheath function. When the normal relationship between internal root sheath and developing hair shaft is disturbed, shaft movement slows, with the subsequent development of shaft calibre abnormalities.
pk acts at the level of the sebaceous gland, disturbing the normal process of hair eruption. The roles of the internal root sheath, external root sheath and the sebaceous gland in hair eruption are discussed.
The abnormal epidermal layer in soc/soc and Ve /+ skin also disturbs hair eruption to a small extent. The resulting abnormalities this causes in hair shaft formation are compared with those found pk/pk samples and also with the similar effects of faulty hair movement in the hair waving mutants. An effect on pigmentation is also described.
The chemistry of keratinization appears to be normal in all these mutants.