Range expansion and potential dispersal mechanisms of the exotic cladoceran Daphnia lumholtzi

. Recently the exotic cladoceran Daphnia lumholtzi has invadedfreshwater systems throughout the southern and midwestern UnitedStates. We conducted regional surveys of eastern Kansas reservoirsto document the range expansion of D.lumholtzi. Daphnia lumholtziwas found in five of 35 reservoirs sampled in 1994, and 11 ofthe 35 reservoirs when re-sampled in 1997. In addition, we sampled40 small ponds inaccessible to recreational boats, within thewatershed of an invaded reservoir. We did not find D.lumholtziin any of these ponds, suggesting that non-human dispersal mechanismsplay an insignificant role in the range expansion of D.lumholtzithroughout the United States. Further experimentation, however,is needed to determine if the absence of D.lumholtzi from thesesmall ponds is due to insufficient dispersal mechanisms or theinability of this invader to successfully colonize followingarrival. Daphnia lumholtzi has broad limnological tolerances.However, invaded reservoirs tend to be larger in area, havehigher Secchi disk depths, and lower total phosphorus, totalnitrogen and chlorophyll a levels relative to non-invaded reservoirs.Analyses of pre-invasion zooplankton communities indicate thatD.lumholtzi may be invading reservoirs in which native Daphniaspecies are rare. While the long-term effects of the invasionof D.lumholtzi are unknown, it has the potential to dominatelate summer zooplankton communities in eastern Kansas reservoirs.Therefore, we need to continue to survey and monitor invadedreservoirs to document the range expansion of D.lumholtzi anddetermine the long-term implications of the introduction ofthis invader.     

Inhibition of Nitric Oxide Synthase Blocks N-Methyl-D-Aspartate-, Quisqualate-, Kainate-, Harmaline-, and Pentylenetetrazole-Dependent Increases in Cerebellar Cyclic GMP In Vivo

The synthesis of nitric oxide by brain slices has been demonstrated in several laboratories. In addition, in vitro studies have demonstrated stimulation of nitric oxide synthesis by excitatory amino acid receptor agonists. These data have led to the hypothesis that this readily diffusible "intercellular messenger molecule" acts to generate a cascade effect by activating guanylate cyclase in several cell types and thereby augment levels of the second messenger cyclic GMP (cGMP). Therefore, we evaluated this hypothesis in vivo, by testing the actions of the nitric oxide synthase inhibitor N-mono-methyl-L-arginine (NMMA) on elevations in level of mouse cerebellar cGMP generated by excitatory amino acid receptor agonists. The stimulatory effects of D-serine, quisqualate, and kainate were all found to be antagonized by this enzyme inhibitor. In addition, NMMA antagonized the increases in cerebellar cGMP level elicited by harmaline and pentylenetetrazole, pharmacological agents that augment endogenous excitatory amino acid transmission. Our data are, therefore, the first in vivo demonstration that nitric oxide is an important "messenger molecule" in the cerebellum, mediating the actions of kainate, quisqualate, and N-methyl-D-aspartate receptor agonists on guanylate cyclase. These data are consistent with previous in vitro findings with kainate and N-methyl-D-aspartate.     

An investigation of the role of circulating catecholamines in the control of ventilation during acute moderate hypoxia in rainbow trout (Oncorhynchus mykiss)

Summary Gill ventilation volume ( w), arterial blood oxygen tension (PaO₂) and arterial blood oxygen content (CaO₂) of rainbow trout (Oncorhyncus mykiss) were monitored during normoxia [waterPO₂ (PwO₂) 155 Torr], hypoxia (PwO₂=72±5.8 Torr), or hyperoxia (PwO₂=643±32 Torr). Fish hyperventilated during acute (30 min) hypoxia and hypoventilagted during acute hyperoxia. Plasma catecholamine levels were unchanged after 30 min of hypoxia or hyperoxia. In addition, selective adrenoceptor blockade with either propranolol (-adrenoceptor antagonist) or phentolamine (-adrenoceptor antagonist) did not modify the hyperventilatory response during hypoxia. These results indicate that circulating catecholamines are not involved in the control of ventilation in moderately hypoxic rainbow trout. In the summer, intra-arterial infusion of catecholamine in normoxic trout caused transient (adrenaline) or persistent (noradrenaline) hypoventilation. These observations also do not support a role for catecholamines in the stimulation of ventilation.During hypoxia,PwO₂,PaO₂ andCaO₂ were depressed whereas during hyperoxia, onlyPwO₂ andPaO₂ was elevated significantly. Thus, it is suggested that the hypoventilatory response to hyperoxia is mediated by a direct effect of elevatedPwO₂/PaO₂, whereas the hyperventilatory response to hypoxia is mediated by changes inPwO₂/PaO₂, and/orCaO₂.     

N α -Dimethylcoprogens Three novel trihydroxamate siderophores from pathogenic fungi

Summary Three novel siderophores have been isolated from a highly pathogenic strain ofAlternaria longipes (ATCC 26293). The compounds are N -dimethylated analogs of coprogen, neocoprogen I and isoneocoprogen I. Structures of the compounds have been determined by¹H- and¹³C-NMR, fast-atom-bombardment (FAB) mass spectroscopy and partial hydrolysis. One of the new compounds, N -dimethylcoprogen, is also produced, as the major siderophore, in another fungus,Fusarium dimerum.     

The fate of ‘biodegradable’ plastics in municipal leaf compost

Summary Blends of starch with polypropylene, starch with polyethylene, polycaprolactone with polyethylene, and a copolymer of -hydroxybutyrate and -hydroxyvalerate (PHB/V) were exposed to degrading leaves in a municipal leaf composting operation. Every month for 6 months, duplicate samples were analyzed for changes in weight and tensile properties, and many of these samples were further analyzed for changes in molecular weight and surface morphology. All results were compared to controls which were incubated for 6 months in moist, sterile leaves at a leaf compost temperature. Very little change was noted for any of the polyolefin blends over the 6-month period. In contrast, PHB/V samples showed massive deterioration with substantial weight loss. Although there was a decrease in molecular weight and a loss of tensile properties in leaf-exposed PHB/V films, the sterile control films also showed similar changes, but without weight loss. Of the microbial isolates from film surfaces, only fungi possessed PHB/V depolymerase activity.     

The prognostic value of the furosemide stress test in predicting delayed graft function following deceased donor kidney transplantation

Objectives and methods: The Furosemide Stress Test (FST) is a novel dynamic assessment of tubular function that has been shown in preliminary studies to predict patients who will progress to advanced stage acute kidney injury, including those who receive renal replacement therapy (RRT). The aim of this study is to investigate if the urinary response to a single intraoperative dose of intravenous furosemide predicts delayed graft function (DGF) in patients undergoing deceased donor kidney transplant.

Results: On an adjusted multiple logistic regression, a single 100?mg dose of intraoperative furosemide after the anastomosis of the renal vessels (FST) predicted the need for RRT at 2 and 6?h post kidney transplantation (KT). Recipient urinary output was measured at 2 and 6?h post furosemide administration. In receiver-operating characteristic (ROC) analysis, the FST predicted DGF with an area-under-the curve of 0.85 at an optimal urinary output cut-off of <600 mls at 6?h with a sensitivity of and a specificity of 83% and 74%, respectively.

Conclusions: The FST is a predictor of DGF post kidney transplant and has the potential to identify patients requiring RRT early after KT.     

High-throughput marker assays for <Emphasis Type="Italic">FaRPc2</Emphasis>-mediated resistance to Phytophthora crown rot in octoploid strawberry

Phytophthora crown rot (PhCR) caused by Phytophthora cactorum is a destructive disease of the allo-octoploid cultivated strawberry (Fragaria ×ananassa Duch). Many major strawberry cultivars grown worldwide are susceptible to PhCR. Resistance is conferred by the recently-discovered FaRPc2 locus, but high-throughput markers are not yet available for marker-assisted breeding. In the current study, we developed DNA markers for two haplotypes at the FaRPc2 locus associated with resistance, H2 and H3. Marker validation and marker-assisted selection were performed in University of Florida (UF) breeding population. Seven single nucleotide polymorphism-based high resolution melting (HRM) markers linked to H2 and four HRM markers for H3 were developed. One HRM marker, RPCHRM3 linked to H3, was converted to a Kompetitive Allele Specific PCR (KASP) marker. To further examine the utility of the markers, they were screened in University of California Davis cultivars with known phenotypes as well as in 20 diverse accessions with phenotypes that are reported in the literature and that are preserved at the USDA-ARS National Clonal Germplasm Repository, in Corvallis, Oregon. The most informative markers for FaRPc2 resistance are being implemented in the UF strawberry breeding program to improve PhCR resistance.     

A role for artificial night-time lighting in long-term changes in populations of 100 widespread macro-moths in UK and Ireland: a citizen-science study

The abundance of 100 of the most widespread species of macro-moth in the UK and Ireland was estimated from light-trap records reported to the UK and Ireland Garden Moth Scheme between 2005 and 2015. Recording sites were classified into low, medium and high night-time illumination categories by satellite imagery, into land-use types from the dominant use in the 1–2 km surrounding area, and by latitude. Most urban sites were in the group classified as having high night-time illumination. Comparison between medium and low night-time illuminated sites allowed differences between levels of illumination free from the effect of urbanization on moth abundance to be assessed. The medium and low night-time illuminated sites differed significantly in the frequency of grassland and arable land-use types and in geographic location with more grassland and north-western sites in the low-light category. After adjustment for these differences and for variations between taxonomic family groups, the medium to low night-time lighting abundance ratios explained a significant (P?<?0.001) 20% of the variance in long-term changes in moth abundance reported by the Rothamsted Insect Survey for the years 1968–2002. This is the first demonstration that artificial night-time lighting has had, in combination with other factors, a significant influence on levels of abundance of moth populations.     

Floral markers and biological activity of Saudi honey

The objectives of this research were to identify certain chemical compounds that may be used as fingerprints of Saudi honey and to evaluate their antioxidant and antibacterial activities. Eleven Saudi ‘monofloral’ honey samples were analyzed and evaluated. Non-phenolic compounds, such as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, methyl 3-hydroxyhexanaote and 5-hydroxymethyl-2-furancarboxaldehyde were present in different types of tested honey samples. Glyceraldehyde was only detected in five of the honey samples tested. The most promising result was the detection of an alkaloid (by using GC–MS) in only two types of Saudi honey samples. This alkaloid may be of great importance and has the potential to be used as a fingerprint marker for the botanical sources of the various honey samples tested. This alkaloid was present in Toran and Saha. The detected compound is 2-amino-4-hydroxypteridine-6-carboxylic acid, which may originate from the degradation of folic acid as identified by previous studies. These findings can be used as a gateway to obtain a fingerprint for these two types of honey samples and can potentially be used to track any impurities in honey sold on the market. All of the tested honey samples showed antioxidant and antibacterial activities. The highly effective activity was in Toran honey against Staphylococcus aureus and Methicillin resistant Staphylococcus aureus (MRSA). Shafalah honey was effective against MRSA and Acinetobacter baumannii which showed bactericidal effects at concentrations 70–100%. This study also examined the antioxidant activity of honey samples using the DPPH assay. DPPH values of tested honey samples varied between 53.93?±?0.21%, as the highest value and 5.89?±?0.125%, as the lowest value. Significant correlations between the antibacterial and the antioxidant activities of the tested honey samples were noticed. The corresponding total phenolic contents (TPC) values supported the fact that phenolic compounds enhanced the antibacterial activity. The study revealed that some of the locally produced honey samples, specifically Zaitoon, Shaflah, Saha, Rabea Aja and Bareq contained the monosaccharides called glyceraldehydes which was the precursor to produce methylglyoxal (MGO) compound, which has antibacterial effects as documented in several previous studies. There was no clear relationship between these activities and the sum total of phenolic compounds present in Saudi honey.     

<Emphasis Type="Italic">Ex vitro</Emphasis> rooting using a mini growth chamber increases root induction and accelerates acclimatization of Kopyor coconut (<Emphasis Type="Italic">Cocos nucifera</Emphasis> L.) embryo culture-derived seedlings

Ex vitro rooting using a mini growth chamber to maintain relative humidity has been used to mass produce true-to-type Kopyor coconut (Cocos nucifera L.) seedlings through embryo culture. This new process was found to (1) improve the proportion of seedlings successfully transferred to soil (from 40 to 90% for seedlings with roots); (2) achieve this step in the shortest time possible (a reduction from 10 to 4 mo in in vitro culture); (3) improve root formation using indolebutyric acid (IBA; an improvement in the number of primary roots from 2 to 5); and (4) improve the vigor of seedlings ex vitro (improvements of fresh weight, shoot length, number of opened leaves, leaf thickness, amount of epicuticular wax, and stomatal density). The best ex vitro rooting and rapid acclimatization protocol was obtained when 4-mo-old seedlings with two opened leaves were kept in the mini growth chamber for 3 mo before being transferred into soil, and when the mini growth chamber was flooded with a quarter strength hybrid embryo culture (HEC) medium with 1 μM IBA but depleted of vitamins and sugar. This protocol was efficient in delivering high-value Kopyor seedlings to the field (90% success rate), with a decreased risk of contamination and lower labor cost. The improved process was found applicable to both tall and dwarf Kopyor and other coconut types.