Proximate Composition and Nutrient Elements in the “Unusual” Algal “Jellies” of Lake Oguta in Southern Nigeria

The proximate composition, nutrient and trace elements of the planktonic algal “jellies” of Lake Oguta in Southern Nigeria, are provided as guides to their utilization and control, using flood (rainy) and dry season samples. These “jellies” are an unusual, macroscopic planktonic algal community in the lake, made up mostly of blue-green algae (Microcystis, Anabaena, Chroococcus) with some green algae (e. g. Spirogyra) and pennate diatoms (e.g. Navicula) rather epiphytic on the mucous jellies of the blue-green algae. Water content was high (98.2% mean, range 97.5-99.5%). Ash, protein and fat had values of 41.7 (39.0-46.2%), 16.9 (15.6-19.4%), and 2.0 (1.7-2.1%) respectively. Crude fibre and carbohydrates were high (25.8% and 12.4%). The levels of phosphorus and nitrogen were rather high, so were the major cations whose order of dominance (Ca > K > Mg > Na) differed from that of the lake water. Macronutrients increased in their concentrations during the rainy flood season while the reverse was the case with the micronutrients. Diagenesis of the endogenic minerals rather than anthropogenic factors are thought to be the reason for the seasonal changes in the ionic concentrations. Possible uses of the algal jellies are discussed as well as their control options.     

Preliminary Observations on the Nature,Taxonomic Composition,Distribution, Behaviour and Nutrient Requirements of the “Unusual” Algal “Jellies” of Oguta Lake in Southeastern Nigeria

Preliminary observations were made between October 1982 and May 1983 on the nature, taxonomic composition, spatial distribution, buoyancy behaviour and nutrient requirements of some unusual planktonic algal “jellies” in Oguta Lake in Southeastern Nigeria. These “jellies” are macroscopic, blue-green algal masses whose excessive mucilage of high consistency acts as substrata for other epiphytic components viz. diatoms and green algae. They are more abundant in the lentic areas of the lake, undergo diurnal vertical movements and have their growth enhanced by spikes of nitrogen and phosphorus salts into their aquatic medium. The effects of these “jellies” on the ecology and general water use of the lake are discussed. Speculations on the reasons for their occurrence are given and possible control measures outlined.     

Rapid detection of “Candidatus Phytoplasma mali” by recombinase polymerase amplification assays

Isothermal recombinase polymerase amplification (RPA) assays for the specific detection of “Candidatus Phytoplasma mali (Ca. P. mali),” the causal agent of apple proliferation, were developed. The assays amplify a fragment of the imp gene and amplimers were detected either by fluorescence in real‐time mode (TwistAmp^®exo assay) using a fluorophore‐labelled probe or by direct visualization employing a lateral flow device (TwistAmp^®nfo assay/Milenia^®HybriDetect). The RPA assays specifically amplified DNA from “Ca. P. mali” strains, and cross‐reactivity with other phytoplasmas or plant DNA was not observed. The limit of detection was determined with a cloned imp standard, and positive results were obtained down to 10 copies with both RPA assay formats. In comparison with a TaqMan real‐time PCR assay based on the same target gene, the RPA assays were equally sensitive, but results were obtained faster. Simplified nucleic acid extraction procedures from plant tissue with Tris‐ and CTAB‐based buffers revealed that crude Tris–DNA extracts were a suitable source for RPA tests while larger concentrations of CTAB were inhibitory. This is the first report of RPA‐based assays for the detection of “Ca. P. mali”. The assays are suitable for high‐throughput screening of plant material and point‐of‐care diagnostic and can be potentially combined with a simplified DNA extraction procedure.     

“Candidatus Phytoplasma asteris” and “Candidatus Phytoplasma mali” strains infecting sweet and sour cherry in the Czech Republic

A survey for phytoplasma diseases was conducted in a sweet and sour cherry germplasm collection and in cherry orchards within the Czech Republic during 2014–2015. Phytoplasmas were detected in 21 symptomatic trees. Multiple infections of cherry trees by diverse phytoplasmas of 16SrI and 16SrX groups and 16SrI‐A, 16SrI‐B, 16SrI‐L, 16SrX‐A subgroups were detected by restriction fragment length polymorphism (RFLP). Nevertheless, phylogenetic analysis placed subgroups 16SrI‐B and 16SrI‐L inseparable together onto one branch of phylogenetic tree. This is the first report of subgroups 16SrI‐A and 16SrI‐L in Prunus spp., and subgroup 16SrX‐A in sour cherry trees. Additionally, novel RFLP profiles for 16SrI‐A and 16SrI‐B‐related phytoplasmas were found in cherry samples. Phytoplasmas with these novel profiles belong, however, to their respective 16SrI‐A or 16SrI‐B phylogenetic clades.     

“Ectrogella” Parasitoids of the Diatom Licmophora sp. are Polyphyletic

The diatom genera Licmophora and Fragilaria are frequent epiphytes on marine macroalgae and can be infected by intracellular parasitoids traditionally assigned to the oomycete genus Ectrogella. Much debate and uncertainty remains about the taxonomy of these oomycetes, not least due to their morphological and developmental plasticity. Here, we used single‐cell techniques to obtain partial sequences of the parasitoids 18S and cox2 genes. The former falls into two recently identified clades of Pseudo‐nitzschia parasites temporarily named OOM_1_2 and OOM_2, closely related to the genera of brown and red algal pathogens Anisolpidium and Olpidiopsis. A third group of sequences falls at the base of the red algal parasites assigned to Olpidiopsis. In one instance, two oomycete parasitoids seemed to co‐exist in a single diatom cell; this co‐occurrence of distinct parasitoid taxa not only within a population of diatom epiphytes, but also within the same host cell, possibly explains the ongoing confusion in the taxonomy of these parasitoids. We demonstrate the polyphyly of Licmophora parasitoids previously assigned to Ectrogella (sensu Sparrow, 1960) and show that parasites of red algae assigned to the genus Olpidiopsis are most likely not monophyletic. We conclude that combining single‐cell microscopy and molecular methods is necessary for their full characterisation.     

Curious structure in “canonical” alanine-based peptides

We have performed all atom simulations of blocked peptides of the form (AAXAA)₃, where X = Gln, Asn, Glu, Asp, Arg, and Lys with explicit water molecules to examine the interactions between side chains spaced i,i–5 in the sequence. Although side chains in this i,i–5 arrangement are commonly believed to be noninteracting, we have observed the formation of unusual i,i–5 main chain hydrogen bonding in such sequences with positively charged residues (Lys) as well as polar uncharged groups (Gln). Our results are consistent with the unusual percentage of hydrogen bonding curves produced by amide exchange measurements on the well-studied sequence acetyl-(AAQAA)₃-amide in water (Shalongo, W., Dugad, L., Stellwagen, E. J. Am. Chem. Soc. 116:8288–8293, 1994). Analysis of our simulations indicated that the glutamine side chain showed the greatest propensity to support π helix formation and that the i,i–5 intramolecular hydrogen bonds were stabilized by water-bridging side chain interactions. This intermittent formation of the unusual π helix structure was observed for up to 23% of the total simulation time in some residues in (AAQAA)₃. Control studies on peptides with glutamine side chains spaced i,i–3, i,i–4, and i,i–6 did not reveal similar unique structures, providing stronger evidence for the unique role side chain interactions with i,i–5 spacing. © 1997 Wiley-Liss Inc.     

Fruit misshapen in strawberry cultivars (Fragaria×ananassa) is related to achenes functionality

Fruit deformation is a phenomenon commonly observed in commercial strawberry cultivars (Fragaria×ananassa) with a negative impact on the economic benefit of crop production. To better understand this physiopathy, we evaluated fruit size and the relative amount of ‘small’ (<0.4 mm) and ‘big’ achenes (>0.6 mm) in misshapen (MF) and well‐formed (WF) fruits from ‘Camarosa’, ‘Ventana’ and ‘Medina’ strawberry cultivars growing in the field. In ‘Camarosa’, size‐dependent achenes functionality was assessed by analysing achenes germinability and differences in time to ripening between MF and WF. We found that the occurrence of fruit deformation was not only strongly dependent on the cultivar (i.e. genetic factor) but also was promoted by low temperatures (i.e. environmental factor). Regardless of the cultivar, MF showed higher percentage of ‘small’ non‐functional achenes than WF, indicating a failure in achene development, which could be related to the functional integrity of reproductive structures. To test this hypothesis, we performed an experiment by pollinating strawberry flowers with pollen developed under low and mild temperatures. Low temperatures reduced pollen viability, and flowers pollinated with low quality pollen led to a higher amount of MF. However, fruit deformation was not completely explained by differences in pollen quality, neither by differences in pistil maturity and receptivity nor ovule viability, suggesting that non‐functional achenes might result from a disruption in postfertilisation processes such as embryo abortion as a consequence of low temperatures.     

Comparative study of the molecularly imprinted polymers prepared by reversible addition–fragmentation chain transfer “bulk” polymerization and traditional radical “bulk” polymerization

Bisphenol A (BPA) and propranolol‐imprinted polymers have been prepared via both reversible addition–fragmentation chain transfer “bulk” polymerization (RAFTBP) and traditional radical “bulk” polymerization (TRBP) under similar reaction conditions, and their equilibrium binding properties were compared in detail for the first time. The chemical compositions, specific surface areas, equilibrium bindings, and selectivity of the obtained molecularly imprinted polymers (MIPs) were systematically characterized. The experimental results showed that the MIPs with molecular imprinting effects and quite fast binding kinetics could be readily prepared via RAFTBP, but they did not show improved template binding properties in comparison with those prepared via TRBP, which is in sharp contrast to many previous reports. This could be attributed to the heavily interrupted equilibrium between the dormant species and active radicals in the RAFT mechanism because of the occurrence of fast gelation during RAFTBP. The findings presented here strongly demonstrates that the application of controlled radical polymerizations (CRPs) in molecular imprinting does not always benefit the binding properties of the resultant MIPs, which is of significant importance for the rational use of CRPs in generating MIPs with improved properties. Copyright © 2013 John Wiley & Sons, Ltd.     

Identification of a Novel 1033‐Nucleotide Deletion Polymorphism in the Prophage Region of ‘Candidatus Liberibacter asiaticus’: Potential Applications for Bacterial Epidemiology

The prophage/phage region in the genome of ‘Candidatus Liberibacter asiaticus’, an alpha‐proteobacterium associated with citrus Huanglongbing, included many valuable loci for genetic diversity studies. Previously, a mosaic genomic region (CLIBASIA_05640 to CLIBASIA_05650) was characterized, and this revealed inter‐ and intracontinental variations of ‘Ca. L. asiaticus’. In this study, 267 ‘Ca. L. asiaticus’ isolates collected from eight provinces in China were analysed with a primer set flanking the same mosaic region plus downstream sequence. While most amplicon sizes ranged from 1400 to 2000 bp, an amplicon of 550 bp (S550) was found in 14 samples collected from south‐western China. Sequence analyses showed that S550 was the result of a 1033 bp deletion which included the previously known mosaic region. The genetic nature of the deletion event remains unknown. The regional restriction of S550 suggests that the ‘Ca. L. asiaticus’ population from south‐western China is different from those in eastern China. The small and easy‐to‐detect S550 amplicon could serve as a molecular marker for ‘Ca. L. asiaticus’ epidemiology.     

Stability Studies on Random Folded RNAs (‘Never Born RNAs’), Implications for the RNA World

In the last years, we have developed a method for the study of random RNA sequences with the aim of investigating their capacity to assume folded and possibly functionally active (ribozymes) structures. The RNA Foster assay developed in our laboratory is a powerful, simple, and fast method to investigate the structural properties of RNA by assessing the presence of secondary domains and their thermal stability through the combination of S1 nuclease activity at different temperatures. In this work, we investigated the structural properties of totally de novo random RNAs, 97‐nucleotides‐long, of which 60 nucleotides were completely random. The rationale behind this was to assess whether and to what extent random RNAs would acquire a stable fold as a prerequisite for catalytic activity. A library of random sequences was created, and 18 sequences were randomly selected and analyzed. Surprisingly, most of the RNAs were resistant to S1 nuclease digestion at up to 50°, and two sequences were resistant even at 70°, suggesting that these totally random RNA molecules could posses a stable secondary structure over a broad range of temperatures under the conditions used. We discuss the possible relevance of these data for the general scenario of the RNA world.     

Molecular Characterization of a Phytoplasma Associated with Potato Witches’‐broom Disease in Iran

Potato plants showing symptoms suggestive of potato witches’‐broom disease including witches’‐broom, little leaf, stunting, yellowing and swollen shoots formation in tubers were observed in the central Iran. For phytoplasma detection, Polymerase Chain Reaction (PCR) and nested PCR assays were performed using phytoplasma universal primer pair P1/P7, followed by primer pair R16F2n/R16R2. Random fragment length polymorphism analysis of potato phytoplasma isolates collected from different production areas using the CfoI restriction enzyme indicated that potato witches’‐broom phytoplasma isolate (PoWB) is genetically different from phytoplasmas associated with potato purple top disease in Iran. Sequence analysis of the partial 16S rRNA gene amplified by nested PCR indicated that ‘Candidatus Phytoplasma trifolii’ is associated with potato witches’‐broom disease in Iran. This is the first report of potato witches’‐broom disease in Iran.     

Phloroglucinol Derivatives from Myrtus communis ‘Variegata’ and Their Antibacterial Activities

Myrtucomvalones D–F, three new triketone‐phloroglucinol‐triketone adducts, and three known ones (myrtucommulone E, myrtucommulone D and callistenone D) were obtained from Myrtus communis ‘Variegata’. Myrtucomvalone D is a pair of enantiomers which was further resolved into (+)‐myrtucomvalone D and (?)‐myrtucomvalone D by chiral HPLC. Their structures and complete stereochemistry were established from interpretation of NMR and crystallographic data and chemical calculations. Myrtucomvalone F, myrtucommulone D and callistenone D showed significant antibacterial activities.     

Genetic diversity of small populations: Not always “doom and gloom”?

Is a key theory of evolutionary and conservation biology—that loss of genetic diversity can be predicted from population size—on shaky ground? In the face of increasing human‐induced species depletion and habitat fragmentation, this question and the study of genetic diversity in small populations are paramount to understanding the limits of species’ responses to environmental change and to providing remedies to endangered species conservation. Few empirical studies have investigated to what degree some small populations might be buffered against losses of genetic diversity. Even fewer studies have experimentally tested the potential underlying mechanisms. The study of Schou, Loeschcke, Bechsgaard, Schlotterer, and Kristensen ( 2017 ) in this issue of Molecular Ecology is elegant in combining classic common garden experimentation with population genomics on an iconic experimental model species (Drosophila melanogaster). The authors reveal a slower rate of loss of genetic diversity in small populations under varying thermal regimes than theoretically expected and hence an unexpected retention of genetic diversity. They are further able to hone in on a plausible mechanism: associative overdominance, wherein homozygosity of deleterious recessive alleles is especially disfavoured in genomic regions of low recombination. These results contribute to a budding literature on the varying mechanisms underlying genetic diversity in small populations and encourage further such research towards the effective management and conservation of fragmented or endangered populations.     

THE EVOLUTION OF COSTLY MATE PREFERENCES II. THE “HANDICAP” PRINCIPLE

We use a general additive quantitative genetic model to study the evolution of costly female mate choice by the “handicap” principle. Two necessary conditions must be satisfied for costly preference to evolve. The conditions are (i) biased mutation pressure on viability and (ii) a direct relationship between the degree of expression of the male mating character and viability. These two conditions explain the success and failure of previous models of the “handicap” principle. Our model also applies to other sources of fitness variation like migration and host-parasite coevolution, which cause effects equivalent to biased mutation.     

“With AIDS I am happier than I have ever been before”

In her 2016 article Sherry Ortner discusses what she calls the rise of ‘dark anthropology’: that is, ethnographic work that analyses situations of domination, dispossession, and violence. She, like Joel Robbins ( 2013 ), posits as a counterpoint the emergence of ‘anthropologies of the good,’ which emphasise care and ethics. In this paper I put these two anthropological projects into generative tension through an analysis of HIV‐positive women's lives in Papua New Guinea. In the first part of the paper I demonstrate the ways in which resource extraction has created vulnerabilities to HIV—in part through the coerced marriages of women to powerful landowners. In the second, I discuss ways in which the antiretroviral era has made possible unexpected forms of kindness towards HIV‐positive women. I end the paper with a discussion of what HIV‐positive women mean when they claim that they are happier now than in their pre‐diagnosis lives.