The ecology of Belizean mangrove-root fouling communities: patterns of epibiont distribution and abundance,and effects on root growth

The aerial prop roots of the neotropical red mangrove,Rhizophora mangle L., begin growing well above highest high water (HHW) and often extend well below lowest low water (LLW) before rooting in the benthic substratum. In Belize, Central America, prop roots growing below LLW are colonized by diverse assemblages of organisms, including macroalgae, hydrozoans, ascidians, sponges, anemones, hard corals, and isopod crustaceans. Mangroves, root-fouling epibionts, root herbivores, and benthic predators engage in complex interactions that are major determinants of mangrove growth and production. Species richness of root epibionts increases with distance from the mainland and with proximity to the barrier reef. Species richness decreases with variability in water temperature and salinity. Ascidians and sponges transplanted from Lark Cay into the coastal Placencia Lagoon failed to survive, but anemones from Lark Cay survived in Placencia Lagoon. Reciprocal transplants survived off-shore. The gastropod predator,Melongena melongena L., present only in mainland estuaries, reduced local barnacle abundance and epibiont species richness in Placencia Lagoon. Isopod species richness also increases with distance from shore, but the number of roots bored by these species decreases. These isopods can reduce root relative growth rate (RGR_root) by 55%. On off-shore cays, sponges and ascidians ameliorate negative effects of isopods. In mainland estuaries where epibionts are less common, isopod damage to roots is more severe. Experimental studies in mangrove swamps throughout the world would clarify the importance of plant-animal interactions in these widespread tropical ecosystems.     

A mutation in the putative Mg(2+)-binding site of Gs alpha prevents its activation by receptors.

The properties of a Gs alpha mutant with an Asn substituted for Ser at position 54, designated mutant 54Asn alpha s, were studied after expression in S49 alpha s-deficient (cyc-) cells. Ser-54 in alpha s is comparable to Ser-17 in Ras, which is involved in binding Mg2+ associated with bound nucleotide. 54Asn alpha s did not restore either hormone-induced cyclic AMP production in intact cyc- cells or hormone-induced adenylyl cyclase activation in membranes isolated from these cells. The defect was a failure of ligand-bound receptor to activate 54Asn alpha s, since the mutant protein retained the ability to activate adenylyl cyclase in isolated membranes in the presence of GTP or GTP gamma S. Guanine nucleotide regulation of mutant alpha s suggested that it has increased guanine nucleotide exchange rates and an increased preference for diphosphates over triphosphates. Hormone stimulation magnified the preference of 54Asn alpha s for diphosphates, which could account for its inability to be activated by receptor. The properties of this mutant are discussed in terms of similarities to and differences with the analogous RasH mutant, which has been shown to interfere with endogenous Ras function in cells.     

Thiamine deficiency in vivo produces fiber cell degeneration in mouse lenses.

Thiamine (Vitamin B1) is a co-factor for enzymes key in bridging aerobic and anaerobic metabolism. One such enzyme, transketolase, catalyzes two of three reactions for entry into the pentose-phosphate pathway, a major source of chemical reducing power. Thus, thiamine deprivation (TD) is considered a classic model of systemic oxidative stress and is linked with degenerative diseases. TD in mice and rats produces neurodegeneration with Alzheimer's disease characteristics. Age-related disease of the lens, commonly cataract, is also linked with thiamine and oxidative stress. To test the effects of TD on mice, we used a previously defined protocol involving a thiamine free diet and a thiamine antagonist. After 12 days, lens fiber cell degeneration was observed primarily along the lens posterior beneath the intact capsule. These regions exhibited a localized increased expression of Alzheimer precursor protein, Abeta peptides, and presenilin 1. These data indicate that TD in mice produces fiber cell degeneration and suggest common mechanisms for TD-induced lens fiber and neuronal cell degeneration.     

A monoclonal antibody targeting a highly conserved epitope in influenza B neuraminidase provides protection against drug resistant strains

All influenza viral neuraminidases (NA) of both type A and B viruses have only one universally conserved sequence located between amino acids 222–230. A monoclonal antibody against this region has been previously reported to provide broad inhibition against all nine subtypes of influenza A NA; yet its inhibitory effect against influenza B viral NA remained unknown. Here, we report that the monoclonal antibody provides a broad inhibition against various strains of influenza B viruses of both Victoria and Yamagata genetic lineage. Moreover, the growth and NA enzymatic activity of two drug resistant influenza B strains (E117D and D197E) are also inhibited by the antibody even though these two mutations are conformationally proximal to the universal epitope. Collectively, these data suggest that this unique, highly-conserved linear sequence in viral NA is exposed sufficiently to allow access by inhibitory antibody during the course of infection; it could represent a potential target for antiviral agents and vaccine-induced immune responses against diverse strains of type B influenza virus.     

Dynamic compressive loading differentially regulates chondrocyte anabolic and catabolic activity with age

Dynamic loading has emerged as an important part of cartilage tissue engineering strategies for enhancing tissue production and producing cartilage with functionally competent mechanical properties. As patients in need of cartilage span a range of age groups, questions arise as to the role of age in a cell's ability to respond to dynamic loading. Therefore, this study's goal was to characterize age‐related anabolic and catabolic responses of chondrocytes to dynamic compressive loading. Bovine chondrocytes isolated from juvenile (3‐week‐old) and adult (2‐ to 3‐year‐old) donors were encapsulated in poly(ethylene glycol) hydrogels and subjected to dynamic loading applied intermittently in a sinusoidal waveform at 1 or 0.3 Hz with 5 or 10% amplitude strain up to 2 weeks. Loading significantly enhanced total sulfated glycosaminoglycan (sGAG) production by 220% for juvenile chondrocytes with 0.3 Hz/5% loading and by 88% for adult chondrocytes with 1 Hz/5% loading, while all other loading regimes did not affect or inhibited total sGAG production. Contrarily, deposition of larger matrix molecules of aggrecan and collagen II was either not affected or inhibited by loading. Collagen VI deposition was significantly upregulated by loading but only in adult chondrocytes and under different loading regimes (1 Hz/10% and 0.3 Hz/5%) when compared to total sGAGs. Both cell populations displayed catabolic activity, which appeared to be stimulated by loading. Taken together, findings from this study suggest that loading differentially regulates matrix synthesis and the response is highly dependent on donor age. Biotechnol. Bioeng. 2013; 110: 2046–2057. © 2013 Wiley Periodicals, Inc.     

Organophosphate and Pyrethroid Hydrolase Activities of Mutant Esterases from the Cotton Bollworm Helicoverpa armigera

Two mutations have been found in five closely related insect esterases (from four higher Diptera and a hymenopteran) which each confer organophosphate (OP) hydrolase activity on the enzyme and OP resistance on the insect. One mutation converts a Glycine to an Aspartate, and the other converts a Tryptophan to a Leucine in the enzymes’ active site. One of the dipteran enzymes with the Leucine mutation also shows enhanced activity against pyrethroids. Introduction of the two mutations in vitro into eight esterases from six other widely separated insect groups has also been reported to increase substantially the OP hydrolase activity of most of them. These data suggest that the two mutations could contribute to OP, and possibly pyrethroid, resistance in a variety of insects. We therefore introduced them in vitro into eight Helicoverpa armigera esterases from a clade that has already been implicated in OP and pyrethroid resistance. We found that they do not generally enhance either OP or pyrethroid hydrolysis in these esterases but the Aspartate mutation did increase OP hydrolysis in one enzyme by about 14 fold and the Leucine mutation caused a 4–6 fold increase in activity (more in one case) of another three against some of the most insecticidal isomers of fenvalerate and cypermethrin. The Aspartate enzyme and one of the Leucine enzymes occur in regions of the H. armigera esterase isozyme profile that have been previously implicated in OP and pyrethroid resistance, respectively.     

Short-Term Space-Use Patterns of Translocated Mojave Desert Tortoise in Southern California

Increasingly, renewable energy comprises a larger share of global energy production. Across the western United States, public lands are being developed to support renewable energy production. Where there are conflicts with threatened or endangered species, translocation can be used in an attempt to mitigate negative effects. For the threatened Mojave desert tortoise (Gopherus agassizii), we sought to compare habitat- and space-use patterns between short-distance translocated, resident, and control groups. We tested for differences in home range size based on utilization distributions and used linear mixed-effects models to compare space-use intensity, while controlling for demographic and environmental variables. In addition, we examined mean movement distances as well as home range overlap between years and for male and female tortoises in each study group. During the first active season post-translocation, home range size was greater and space-use intensity was lower for translocated tortoises than resident and control groups. These patterns were not present in the second season. In both years, there was no difference in home range size or space-use intensity between control and resident groups. Translocation typically resulted in one active season of questing followed by a second active season characterized by space-use patterns that were indistinguishable from control tortoises. Across both years, the number of times a tortoise was found in a burrow was positively related to greater space-use intensity. Minimizing the time required for translocated tortoises to exhibit patterns similar to non-translocated individuals may have strong implications for conservation by reducing exposure to adverse environmental conditions and predation. With ongoing development, our results can be used to guide future efforts aimed at understanding how translocation strategies influence patterns of animal space use.     

Best practice BioBanking of human heart tissue

This review provides a guide to researchers who wish to establish a biobank. It also gives practical advice to investigators seeking access to samples of healthy or diseased human hearts. We begin with a brief history of the Sydney Heart Bank (SHB) from when it began in 1989, including the pivotal role played by the late Victor Chang. We discuss our standard operating procedures for tissue collection which include cryopreservation and the quality assurance needed to maintain the long-term molecular and cellular integrity of the samples. The SHB now contains about 16,000 heart samples derived from over 450 patients who underwent isotopic heart transplant procedures and from over 100 healthy organ donors. These enable us to provide samples from a wide range of categories of heart failure. So far, we have delivered heart samples to more than 50 laboratories over two decades, and we answer their most frequently asked questions. Other SHB services include the development of tissue microarrays (TMA). These enable end users to perform preliminary examinations of the expression and localisation of target molecules in diseased or aging donor hearts, all in a single section of the TMA. Finally, the processes involved in managing tissue requests from external users and logistics considerations for the shipment of human tissue are discussed in detail.

Electronic supplementary material

The online version of this article (doi:10.1007/s12551-015-0182-6) contains supplementary material, which is available to authorized users.     

Antimycobacterial evaluation of Peruvian plants

We present the results of an antimycobacterial screening of 270 Peruvian plant samples representing 216 species from 171 genera in 63 families. Dichloromethane extracts were tested at a concentration of 50 microg/ml for inhibition of Mycobacterium tuberculosis in radiometric culture. Slightly more than half of the samples tested showed inhibition of M. tuberculosis at this concentration.