BIOLUMINESCENCE AND CHLOROPLAST MOVEMENT IN THE DINOFLAGELLATE PYROCYSTIS LUNULA1

The lunate cysts of Pyrocystis lunula have a bioluminescent emission spectrum with a peak intensity of 477.5 ± 1 mμ. The light originates from the protoplasm in the center of the cysts. Six to eight hr after the cysts were placed in the dark, they produced 300 to 800 times more luminescence than controls maintained under constant, illumination. Plastids contract distally when the cysts are placed in the dark. If kept in the dark, the plastids contract distally and expand with a circadian rhythm persisting several days. At intensities of 2200 μm cm-’or less, the plastids are expanded. The plastids are contracted into the central area of the cysts at light intensities of 4000 μw cm-² and above. The Gymnodinium stage of the life cycle is not bioluminescent.     

Efficacy of chemotherapy and thermotherapy in elimination of East African cassava mosaic virus from Tanzanian cassava landrace

Cassava mosaic disease is caused by cassava mosaic begomoviruses (CMBs) and can result in crop losses up to 100% in cassava (Manihot esculenta) in Tanzania. We investigated the efficacy of chemotherapy and thermotherapy for elimination of East African cassava mosaic virus (EACMV) of Tanzanian cassava. In vitro plantlets from EACMV‐infected plants obtained from coastal Tanzania were established in the greenhouse. Leaves were sampled from the plants and tested to confirm the presence of EACMV. Plantlets of plants positive for EACMV were initiated in Murashige and Skoog (MS) medium. On the second subculture, they were subjected into chemical treatment in the medium containing salicylic acid (0, 10, 20, 30 and 40 mg/L) and ribavirin (0, 5, 10, 15 and 20 mg/L). In the second experiment, EACMV‐infected plantlets were subjected to temperatures between 35 and 40°C with 28°C as the control. After 42 days of growth, DNA was extracted from plant leaves and PCR amplification was performed using EACMV specific primers. It was found that plant survival decreased with increasing levels of both salicylic acid and ribavirin concentrations. In general, plants treated with salicylic acid exhibited a lower plant survival % than those treated with ribavirin. However, the percentage of virus‐free plants increased with an increase in the concentration of both ribavirin and salicylic acid. The most effective concentrations were 20 mg/L of ribavirin and 30 mg/L of salicylic acid; these resulted in 85.0% and 88.9% virus‐free plantlets, respectively. With regard to thermotherapy, 35°C resulted in 79.5% virus‐free plantlets compared to 69.5% at 40°C. Based on virus elimination, ribavirin at 20 mg/L, salicylic acid 30 mg/L and thermotherapy at 35°C are recommended for production of EACMV free cassava plantlets from infected cassava landraces.     

Renaming restoration: conceptualizing and justifying the activity as a restoration of lost moral value rather than a return to a previous state

A significant percentage of contemporary restoration work, while informed by history, aims for a novel state rather than an exact simulacrum of any particular historical state. However, the lay definition of “restoration” is to return something to its original state, and this influences public perceptions—and perhaps perceptions inside the field—about what the goals of restoration are. Relying on history to justify the proposed end state of a restoration project is problematic because of climate change, knowledge gaps, and the fact that ecosystems are dynamic and have no single historical state. Restorationists should be open to discussing whether the name of their field is inaccurate and considering alternatives. The process productively forces them to think about, articulate, and justify their values. One possible outcome of this process is a redefinition of “restoration” to mean a restoration of moral value rather than a restoration of a historical state. Restorationists will need to be comfortable talking about choices, intentions, values, and justifications in a world where historical fidelity no longer reigns supreme.     

Population-Level Density Dependence Influences the Origin and Maintenance of Parental Care

Parental care is a defining feature of animal breeding systems. We now know that both basic life-history characteristics and ecological factors influence the evolution of care. However, relatively little is known about how these factors interact to influence the origin and maintenance of care. Here, we expand upon previous work and explore the relationship between basic life-history characteristics (stage-specific rates of mortality and maturation) and the fitness benefits associated with the origin and the maintenance of parental care for two broad ecological scenarios: the scenario in which egg survival is density dependent and the case in which adult survival is density dependent. Our findings suggest that high offspring need is likely critical in driving the origin, but not the maintenance, of parental care regardless of whether density dependence acts on egg or adult survival. In general, parental care is more likely to result in greater fitness benefits when baseline adult mortality is low if 1) egg survival is density dependent or 2) adult mortality is density dependent and mutant density is relatively high. When density dependence acts on egg mortality, low rates of egg maturation and high egg densities are less likely to lead to strong fitness benefits of care. However, when density dependence acts on adult mortality, high levels of egg maturation and increasing adult densities are less likely to maintain care. Juvenile survival has relatively little, if any, effect on the origin and maintenance of egg-only care. More generally, our results suggest that the evolution of parental care will be influenced by an organism’s entire life history characteristics, the stage at which density dependence acts, and whether care is originating or being maintained.     

Improving yield performance of Pleurotus pulmonarius through hyphal anastomosis fusion of dikaryons

High production and good quality are always the principal goals for agriculturally important crops, without the exception of mushrooms. P. pulmonarius is one of the commercially important edible mushrooms throughout the world. The yield performance improvement was carried out by cross bred P. pulmonarius with P. sapidus and P. ostreatus. The highest rate of 0.587 mm/days for spawn ramification and 53.33 % for percentage spawn productivity were obtained in hybrids LN LL910. The least day (11 and 12th) of the primodia mushroom sporophore were recorded in LL910 and LN 97 respectively, while longest day of 19th was recorded in wild type (NE 07). The highest biological efficiency (109.30 %) and production rate (3.77 %) obtained by LL910, while the least of 33.0 and 0.79 % were obtained by NE 07 for biological efficiency and production rate respectively. The morphological and molecular characterization of the hybrid strains established their true variation from their wild type. LL 910 (JF68088) is located at seventh subclusters from the root with boostrap value of 32 %, while only one parent (LAU 09: JF736658) out of the two has the close boostrap value of 43 % at the first subcluster to the root, with the other parent LAU 10 (JF736659) shows distance relationship after Blast. LN 97 (JF680992) is located at outgroup, while the parent strains NE 07 (boostrap value: 11 %) and LAU 09 (boostrap value: 44 %) located at tenth and second subclusters respectively. The results obtained from this study have shown the improved performance of the hybrids strain over wild type strains.     

Horizontal gene transfer of zinc and non-zinc forms of bacterial ribosomal protein S4

Background  

The universal ribosomal protein S4 is essential for the initiation of small subunit ribosomal assembly and translational accuracy. Being part of the information processing machinery of the cell, the gene for S4 is generally thought of as being inherited vertically and has been used in concatenated gene phylogenies. Here we report the evolution of ribosomal protein S4 in relation to a broad sharing of zinc/non-zinc forms of the gene and study the scope of horizontal gene transfer (HGT) of S4 during bacterial evolution.     

MultiSeq: unifying sequence and structure data for evolutionary analysis

Background  

Since the publication of the first draft of the human genome in 2000, bioinformatic data have been accumulating at an overwhelming pace. Currently, more than 3 million sequences and 35 thousand structures of proteins and nucleic acids are available in public databases. Finding correlations in and between these data to answer critical research questions is extremely challenging. This problem needs to be approached from several directions: information science to organize and search the data; information visualization to assist in recognizing correlations; mathematics to formulate statistical inferences; and biology to analyze chemical and physical properties in terms of sequence and structure changes.     

Systematic characterization of mutations altering protein degradation in human cancers

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Nucleic Acid Template and the Risk of a PCR-Induced HIV-1 Drug Resistance Mutation

Background

The HIV-1 nucleoside RT inhibitor (NRTI)-resistance mutation, K65R confers intermediate to high-level resistance to the NRTIs abacavir, didanosine, emtricitabine, lamivudine, and tenofovir; and low-level resistance to stavudine. Several lines of evidence suggest that K65R is more common in HIV-1 subtype C than subtype B viruses.

Methods and Findings

We performed ultra-deep pyrosequencing (UDPS) and clonal dideoxynucleotide sequencing of plasma virus samples to assess the prevalence of minority K65R variants in subtype B and C viruses from untreated individuals. Although UDPS of plasma samples from 18 subtype C and 27 subtype B viruses showed that a higher proportion of subtype C viruses contain K65R (1.04% vs. 0.25%; p<0.001), limiting dilution clonal sequencing failed to corroborate its presence in two of the samples in which K65R was present in >1.5% of UDPS reads. We therefore performed UDPS on clones and site-directed mutants containing subtype B- and C-specific patterns of silent mutations in the conserved KKK motif encompassing RT codons 64 to 66 and found that subtype-specific nucleotide differences were responsible for increased PCR-induced K65R mutation in subtype C viruses.

Conclusions

This study shows that the RT KKK nucleotide template in subtype C viruses can lead to the spurious detection of K65R by highly sensitive PCR-dependent sequencing techniques. However, the study is also consistent with the subtype C nucleotide template being inherently responsible for increased polymerization-induced K65R mutations in vivo.     

Teratocytes of the solitary endoparasitoid Meteorus gyrator (Hymenoptera: Braconidae): morphology, numbers and possible functions

Abstract. Laboratory studies investigated the development of teratocytes derived from the eggs of the parasitoid Meteous gyrator (Thun.) in its host, the tomato moth Lacanobia oleracea (L.). At hatching, each parasitoid egg produced an average of approximately 1000 teratocytes, but this number declined to approximately 400 during the course of parasitism. The teratocytes increased in size markedly, such that 7 days after egg hatch their mean diameter was approximately four times that of the cells immediately after dissociation. The haemolymph of parasitized hosts had reduced phenoloxidase activity, and teratocytes inhibited phenoloxidase activity when coincubated with plasma from nonparasitized hosts. The injection of teratocytes into nonparasitized fifth‐instar L. oleracea larvae suppressed growth and induced a supernumerary moult in some larvae. A number of parasitism‐specific proteins were detected in the haemolymph of parasitized hosts, and incubation of teratocytes in culture media indicated that these cells were a source of at least two of these proteins.