Estimation of desmosponge (Porifera,Demospongiae) larval settlement rates from short-term recruitment rates: Preliminary experiments

During a study of the spatial and temporal patterns of desmosponge (Porifera, Demospongiae) recruitment on rocky and coral reef habitats of Santa Marta, Colombian Caribbean Sea, preliminary attempts were made to estimate actual settlement rates from short-term (1 to a few days) recruitment censuses. Short-term recruitment rates on black, acrylic plastic plates attached to open, non-cryptic substratum by anchor screws were low and variable (0–5 recruits/plate in 1–2 days, sets of n=5–10 plates), but reflected the depth and seasonal trends found using mid-term (1 to a few months) censusing intervals. Moreover, mortality of recruits during 1–2 day intervals was low (0–12%). Thus, short-term censusing intervals can be used to estimate actual settlement rates. To be able to make statistical comparisons, however, it is necessary to increase the number of recruits per census by pooling data of n plates per set, and to have more than one set per site or treatment.     

Affinity of Ionic Species of Nucleoside Transport Protein Inhibitors

Abstract

A class of very potent nucleoside transport inhibitors is present in two molecular forms around physiological pH. We investigated whether the monoprotonated or the unionized species of these molecules binds to this camer protein with higher affinity.     

Mariculture and Natural Production of the Antitumoural (+)-Discodermolide by the Caribbean Marine Sponge Discodermia dissoluta

Biotechnological research on marine organisms, such as ex situ or in situ aquaculture and in vitro cell culture, is being conducted to produce bioactive metabolites for biomedical and industrial uses. The Caribbean marine sponge Discodermia dissoluta is the source of (+)-discodermolide, a potent antitumoural polyketide that has reached clinical trials. This sponge usually lives at depths greater than 30 m, but at Santa Marta (Colombia) there is a shallower population, which has made it logistically possible to investigate for the first time, on ways to supply discodermolide. We thus performed in situ, 6-month fragment culture trials to assess the performance of this sponge in terms of growth and additional discodermolide production and studied possible factors that influence the variability of discodermolide concentrations in the wild. Sponge fragments cultured in soft mesh bags suspended from horizontal lines showed high survivorship (93 %), moderate growth (28 % increase in volume) and an overall rise (33 %) in the discodermolide concentration, equivalent to average additional production of 8 μg of compound per millilitre of sponge. The concentration of discodermolide in wild sponges ranged from 8 to 40 μg mL^?1. Locality was the only factor related to discodermolide variation in the wild, and there were greater concentrations in peripheral vs. basal portions of the sponge, and in clean vs. fouled individuals. As natural growth and regeneration rates can be higher than culture growth rates, there is room for improving techniques to sustainably produce discodermolide.     

THE EFFECTS OF INJURY PREVENTION WARM-UP PROGRAMMES ON KNEE STRENGTH IN MALE SOCCER PLAYERS

The study investigates the effects of the 11+ and HarmoKnee injury prevention programmes on knee strength in male soccer players. Under-21-year-old players (n=36) were divided equally into: the 11+, HarmoKnee and control groups. The programmes were performed for 24 sessions (20-25 min each). The hamstrings and quadriceps strength were measured bilaterally at 60°·s^-1, 180°·s^-1 and 300°·s^-1. The concentric quadriceps peak torque (PT) of the 11+ increased by 27.7% at 300°·s^-1 in the dominant leg (p<0.05). The concentric quadriceps PT of HarmoKnee increased by 36.6%, 36.2% and 28% in the dominant leg, and by 31.3%, 31.7% and 20.05% at 60°·s^-1, 180°·s^-1 and 300°·s^-1 in the non-dominant leg respectively. In the 11+ group the concentric hamstring PT increased by 22%, 21.4% and 22.1% at 60°·s^-1, 180°·s^-1 and 300°·s^-1, respectively in the dominant leg, and by 22.3%, and 15.7% at 60°·s^-1 and 180°·s^-1, in the non-dominant leg. In the HarmoKnee group the hamstrings in the dominant leg showed an increase in PT by 32.5%, 31.3% and 14.3% at 60°·s^-1, 180°·s^-1 and 300°·s^-1, and in the non-dominant leg hamstrings PT increased by 21.1% and 19.3% at 60°·s^-1 and 180°·s^-1 respectively. The concentric hamstrings strength was significantly different between the 11+ and control groups in the dominant (p=0.01) and non-dominant legs (p=0.02). The HarmoKnee programme enhanced the concentric strength of quadriceps. The 11+ and HarmoKnee programmes are useful warm-up protocols for improving concentric hamstring strength in young professional male soccer players. The 11+ programme is more advantageous for its greater concentric hamstring strength improvement compared to the HarmoKnee programme.     

Na transport proteins are expressed by rat alveolar epithelial type I cells

Despite a presumptive role for type I (AT1) cells in alveolar epithelial transport, specific Na transporters have not previously been localized to these cells. To evaluate expression of Na transporters in AT1 cells, double labeling immunofluorescence microscopy was utilized in whole lung and in cytocentrifuged preparations of partially purified alveolar epithelial cells (AEC). Expression of Na pump subunit isoforms and the alpha-subunit of the rat (r) epithelial Na channel (alpha-ENaC) was evaluated in isolated AT1 cells identified by their immunoreactivity with AT1 cell-specific antibody markers (VIIIB2 and/or anti-aquaporin-5) and lack of reactivity with antibodies specific for AT2 cells (anti-surfactant protein A) or leukocytes (anti-leukocyte common antigen). Expression of the Na pump alpha(1)-subunit in AEC was assessed in situ. Na pump subunit isoform and alpha-rENaC expression was also evaluated by RT-PCR in highly purified (approximately 95%) AT1 cell preparations. Labeling of isolated AT1 cells with anti-alpha(1) and anti-beta(1) Na pump subunit and anti-alpha-rENaC antibodies was detected, while reactivity with anti-alpha(2) Na pump subunit antibody was absent. AT1 cells in situ were reactive with anti-alpha(1) Na pump subunit antibody. Na pump alpha(1)- and beta(1)- (but not alpha(2)-) subunits and alpha-rENaC were detected in highly purified AT1 cells by RT-PCR. These data demonstrate that AT1 cells express Na pump and Na channel proteins, supporting a role for AT1 cells in active transalveolar epithelial Na transport.     

IL-2 signaling in human monocytes involves the phosphorylation and activation of p59hck

The activating properties of IL-2 and the structure of the IL-2R on human monocytes are well characterized. However, relatively little is known about the biochemical mechanisms involved in IL-2 signal transduction in these cells. We investigated the role of protein tyrosine kinases (PTKs) in the activation of monocytes by IL-2. Incubation of monocytes with the PTK inhibitor herbimycin A (HA) resulted in the dose-dependent suppression of IL-2-induced monocyte tumoricidal activity. This inhibition was rather potent, as a concentration of HA as low as 0.5 microM caused a complete abrogation of cytolytic activity. Furthermore, HA markedly suppressed the ability of IL-2 to induce IL-1 beta, TNF-alpha, IL-6, and IL-8 mRNA expression and protein secretion by monocytes. Anti-phosphotyrosine immunoblotting demonstrated that IL-2 induced a rapid and time-dependent increase in tyrosine phosphorylation of several cellular proteins of molecular masses ranging from 35 to 180 kDa. Interestingly, IL-2 caused a significant up-regulation of the constitutive levels of hck PTK mRNA and protein relative to medium-treated cells as well as an increase in p59hck tyrosine phosphorylation. Finally, we demonstrated by in vitro kinase assay that the specific activity of p59hck PTK was also induced by IL-2 in monocytes. Thus, these data show that the activation of PTKs is required for the triggering of monocyte effector and secretory functions by IL-2 and strongly suggest that p59hck is a key participant in IL-2 signaling in human monocytes.     

Transcriptional profiling of bovine intervertebral disc cells: implications for identification of normal and degenerate human intervertebral disc cell phenotypes

Introduction  

Nucleus pulposus (NP) cells have a phenotype similar to articular cartilage (AC) cells. However, the matrix of the NP is clearly different to that of AC suggesting that specific cell phenotypes exist. The aim of this study was to identify novel genes that could be used to distinguish bovine NP cells from AC and annulus fibrosus (AF) cells, and to further determine their expression in normal and degenerate human intervertebral disc (IVD) cells.