Connectivity of Caribbean coral populations: complementary insights from empirical and modelled gene flow

Understanding patterns of connectivity among populations of marine organisms is essential for the development of realistic, spatially explicit models of population dynamics. Two approaches, empirical genetic patterns and oceanographic dispersal modelling, have been used to estimate levels of evolutionary connectivity among marine populations but rarely have their potentially complementary insights been combined. Here, a spatially realistic Lagrangian model of larval dispersal and a theoretical genetic model are integrated with the most extensive study of gene flow in a Caribbean marine organism. The 871 genets collected from 26 sites spread over the wider Caribbean subsampled 45.8% of the 1900 potential unique genets in the model. At a coarse scale, significant consensus between modelled estimates of genetic structure and empirical genetic data for populations of the reef-building coral Montastraea annularis is observed. However, modelled and empirical data differ in their estimates of connectivity among northern Mesoamerican reefs indicating that processes other than dispersal may dominate here. Further, the geographic location and porosity of the previously described east-west barrier to gene flow in the Caribbean is refined. A multi-prong approach, integrating genetic data and spatially realistic models of larval dispersal and genetic projection, provides complementary insights into the processes underpinning population connectivity in marine invertebrates on evolutionary timescales.     

Development of pig embryos by nuclear transfer of cultured fibroblast cells

Pig fibroblast cells were transferred to enucleated oocytes by micromanipulation and electrofusion. The donor cells used for nuclear transfer were synchronized in presumptive G0 by serum starvation. In the first experiment, nuclear transfer was performed with fibroblasts that had either a smooth or a rough surface. A significant difference (p < 0.05) in the percentage of chromosome condensation (39.5%, 15/38 and 16.6%, 5/30) and nuclear formation (36.8%, 14/38 and 16.3%, 8/49) was found between the reconstructed embryos derived from the cells with smooth surface and with rough surfaces, respectively. The percentage of chromosome condensation (42.5%, 17/40 and 19.6%, 11/56) and nuclear formation (38.3%, 23/60 and 18.8%, 9/48) were higher (p < 0.05) in reconstructed embryos derived from small (15 microm) donor cells compared to large donor cells (20 microm), respectively. The percentage nuclei at 3 different time points (3, 6, and 9 hours in culture medium) was higher (p = 0.003) in the reconstructed embryos activated by thimerosal and dithiothreitol (20%, 36%, and 41.3%) compared to those without activation treatment (0%, 11.8%, and 22.2%). In addition, there was an increased percentage with nuclei as the time in culture increased from 3 to 9 hours (p = 0.029). The percentages of chromosome condensation (34.6%; 9/26) and nuclear formation (33.3%; 9/27) in nuclear transfer embryos were similar. The rate of blastocysts/morulae development (14.0%; 6/43) was low. However, 2 cavitated embryos (presumptive blastocysts) with 14 and 11 nuclei and 1 morula with 8 nuclei were obtained. This together with the above evidence indicate that the nuclei from pig fibroblast cells can be partially reprogrammed, which suggests that transfer of nuclei from fibroblast cells to in vitro matured oocytes resulting in production of identical or genetically altered pigs may be possible.     

A protein tyrosine phosphatase inhibitor, sodium orthovanadate, causes parthenogenetic activation of pig oocytes via an increase in protein tyrosine kinase activity.

This study was conducted to determine whether a protein tyrosine kinase (PTK) activity is involved in the initiation of the events that occur at fertilization in pig oocytes. After maturation for 47 h, a 7-h treatment of oocytes with 1 mM sodium orthovanadate, which is an inhibitor of protein tyrosine phosphatase, caused more than 90% pronuclear formation, cortical granule exocytosis, and a decrease in mitogen-activated protein kinase activity. Immunoblotting with an antibody specific for phosphotyrosine showed at least three proteins whose phosphotyrosine contents were significantly increased upon treatment of oocytes with 1 mM sodium orthovanadate. Preincubation of pig oocytes with 50 microM tyrphostin 47, a specific PTK inhibitor, completely blocked the ability of sodium orthovanadate to trigger activation events. In addition, when oocytes were pretreated with the calcium-chelating agent BAPTA-AM, sodium orthovanadate-stimulated pronuclear formation was significantly (P < 0.01) reduced (94.0% vs. 43.1%). These results suggest that PTK may be involved in pig oocyte activation in a calcium-dependent manner and that the stimulation of tyrosine kinase is able to signal a series of intracellular changes that lead to the activation events associated with fertilization.     

Histidine button engineered into cardiac troponin I protects the ischemic and failing heart

The myofilament protein troponin I (TnI) has a key isoform-dependent role in the development of contractile failure during acidosis and ischemia. Here we show that cardiac performance in vitro and in vivo is enhanced when a single histidine residue present in the fetal cardiac TnI isoform is substituted into the adult cardiac TnI isoform at codon 164. The most marked effects are observed under the acute challenges of acidosis, hypoxia, ischemia and ischemia-reperfusion, in chronic heart failure in transgenic mice and in myocytes from failing human hearts. In the isolated heart, histidine-modified TnI improves systolic and diastolic function and mitigates reperfusion-associated ventricular arrhythmias. Cardiac performance is markedly enhanced in transgenic hearts during reperfusion despite a high-energy phosphate content similar to that in nontransgenic hearts, providing evidence for greater energetic economy. This pH-sensitive 'histidine button' engineered in TnI produces a titratable molecular switch that 'senses' changes in the intracellular milieu of the cardiac myocyte and responds by preferentially augmenting acute and long-term function under pathophysiological conditions. Myofilament-based inotropy may represent a therapeutic avenue to improve myocardial performance in the ischemic and failing heart.     

Survival of boll weevil （Coleoptera： Curculionidae） adults after feeding on pollens from various sources

The survival of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, adults on non-cotton hosts in the Lower Rio Grande Valley （LRGV） of Texas was examined from 2001 to 2006. The success of the Boll Weevil Eradication Program, which was reintroduced into the LRGV in 2005, depends on controlling overwintering boll weevil populations. Laboratory studies were conducted using boll weevil adults that were captured in pheromone traps from September through March. The number of adults captured per trap declined significantly in the field from fall to the beginning of spring （3.5-7.0-fold）. The proportion of trapped males and females did not differ significantly. The mean weight of boll weevil adults captured in September was 13.3 mg, while those of captured adults from November to February were significantly lower and ranged from 6.7 to 7.8 mg. Our results show that boll weevil adults can feed on different plant pollens. The highest longevity occurred when adults were fed almond pollen or mixed pollens （72.6 days and 69.2 days, respectively） and the lowest when they fed on citrus pollen or a non-food source （9.7 days or 7.4 days, respectively）. The highest adult survival occurred on almond and mixed pollens [88.0%-97. 6% after 1st feeding period （10 days）, 78.0%-90.8% after 3rd feeding period （10 days）, 55. 0%-83.6% after 5th feeding period （10 days）, and 15.2%-32.4% after lOth feeding period （10 days）]. The lowest adult survival occurred on citrus pollen [52.0%-56.0% after 1st feeding period （10 days）, 13.3% after 3rd and 5th feeding periods （10 days）, and 0 after 6th feeding period （10 days）]. Pollen feeding is not a behavior restricted to adult boll weevils of a specific sex or physiological state. Understanding how boll weevil adults survive in the absence of cotton is important to ensure ultimate success of eradicating this pest in the subtropics.     

Vaginal and pelvic reconstruction with distally based rectus abdominis myocutaneous flaps

This report introduces a new method of vaginal reconstruction using a single rectus abdominis myocutaneous flap based distally. Applications of this flap in reconstruction of major abdominal wall and pelvic defects, such as hemipelvectomies, are also described. The flap is designed to carry a paddle of upper abdominal skin on a distally based muscle and vascular pedicle. Advantages of this flap design are (1) the technique is straightforward and rapid, (2) flap viability is reliable, (3) the epigastric skin-fascial donor defect preserves the anterior rectus fascia distal to the linea semicircularis, which prevents hernia, (4) a large arc of rotation is provided, and (5) the epigastric donor site does not interfere with colostomy and urinary conduit stomas in the pelvic exenteration patient. We have done 11 vaginal reconstructions and 9 major pelvic defect reconstructions with this flap during the last 3 1/2 years. In these 20 patients, the only complications were two partial flap losses. No major flap losses or ventral hernias occurred.     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoit acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced β-lactamase. Strains from the Royal Free Hospital, London were highly resistant to β-lactam antibiotics, erythromycin, trimethoprim and tetracyctines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.     

Carbon Dioxide Effects on Carbohydrate Status and Partitioning in Rice

The atmospheric carbon dioxide (CO₂) concentration has beenrising and is predicted to reach double the present concentrationsometime during the next century. The objective of this investigationwas to determine the long-term effects of different CO₂ concentrationson carbohydrate status and partitioning in rice (Oryza sativaL cv. IR-30). Rice plants were grown season-long in outdoor,naturally sunlit, environmentally controlled growth chamberswith CO₂ concentrations of 160, 250, 330, 500, 660, and 900µmolCO₂ mol¹ air. In leaf blades, the priority between the partitioningof carbon into storage carbohydrates or into export changedwith developmental stage and CO₂ concentration. During vegetativegrowth, leaf sucrose and starch concentrations increased withincreasing CO₂ concentration but tended to level off above 500µmolmol^–1 CO₂. Similarly, photosynthesis also increased withCO2 concentrations up to 500µmol mol^–1 and thenreached a plateau at higher concentrations. The ratio of starchto sucrose concentration was positively correlated with theCO₂ concentration. At maturity, increasing CO₂ concentrationresulted in an increase in total non-structural carbohydrate(TNC) concentration in leaf blades, leaf sheaths and culms.Carbohydrates that were stored in vegetative plant parts beforeheading made a smaller contribution to grain dry weight at CO₂concentrations below 330µmol mol^–1 than for treatmentsat concentrations above ambient Increasing CO₂ concentrationhad no effect on the carbohydrate concentration in the grainat maturity Key words: CO₂ enrichment, starch, sucrose     

Purification and Properties of beta-Glucosidase from Aspergillus terreus

A beta-glucosidase (EC 3.2.1.21) from the fungus Aspergillus terreus was purified to homogeneity as indicated by disc acrylamide gel electrophoresis. Optimal activity was observed at pH 4.8 and 50 degrees C. The beta-glucosidase had K(m) values of 0.78 and 0.40 mM for p-nitrophenyl-beta-d-glucopyranoside and cellobiose, respectively. Glucose was a competitive inhibitor, with a K(i) of 3.5 mM when p-nitrophenyl-beta-d-glucopyranoside was used as the substrate. The specific activity of the enzyme was found to be 210 IU and 215 U per mg of protein on p-nitrophenyl-beta-d-glucopyranoside and cellobiose substrates, respectively. Cations, proteases, and enzyme inhibitors had little or no effect on the enzyme activity. The beta-glucosidase was found to be a glycoprotein containing 65% carbohydrate by weight. It had a Stokes radius of 5.9 nm and an approximate molecular weight of 275,000. The affinity and specific activity that the isolated beta-glucosidase exhibited for cellobiose compared favorably with the values obtained for beta-glucosidases from other organisms being studied for use in industrial cellulose saccharification.