Flocculation and pentadecane production of a novel filamentous cyanobacterium <Emphasis Type="Italic">Limnothrix</Emphasis> sp. strain SK1-2-1

Objective

A novel filamentous cyanobacterium, a photosynthesizing microorganism, was isolated from a river, and its unique features of flocculation and pentadecane production were characterized.

Results

Microscopic observations and a phylogenetic analysis with 16S rDNA revealed that this strain was a Limnothrix species denoted as the SK1-2-1 strain. Auto cell-flocculation was observed when this strain was exposed to a two-step incubation involving a standing cultivation following a shaking preincubation. Flocculation was enhanced by blue light at a wavelength at 470 nm and irradiation for several hours to 1 day. Moreover, the strain exhibiting exponential cell growth may preferentially accumulate alkanes as pentadecane C₁₅H₃₂ alkane, which may be used as jet fuel, at a range of approximately 1% in the dry cell weight of flocculated cells.

Conclusion

This is the first study on biofuel production using flocculated cells in which the specific manner of production may be regulated by cultivation conditions.

     

Action of fibroblast growth factor-2 on the intervertebral disc

Introduction  

Fibroblast growth factor 2 (FGF2) is a growth factor that is immediately released after cartilage injury and plays a pivotal role in cartilage homeostasis. In human adult articular cartilage, FGF2 mediates anti-anabolic and potentially catabolic effects via the suppression of proteoglycan (PG) production along with the upregulation of matrix-degrading enzyme activity. The aim of the present study was to determine the biological effects of FGF2 in spine disc cells and to elucidate the complex biochemical pathways utilized by FGF2 in bovine intervertebral disc (IVD) cells in an attempt to further understand the pathophysiologic processes involved in disc degeneration.     

A representation of a compressed de Bruijn graph for pan-genome analysis that enables search

Background

Recently, Marcus et al. (Bioinformatics 30:3476–83, 2014) proposed to use a compressed de Bruijn graph to describe the relationship between the genomes of many individuals/strains of the same or closely related species. They devised an \(O(n\log g)\) time algorithm called splitMEM that constructs this graph directly (i.e., without using the uncompressed de Bruijn graph) based on a suffix tree, where n is the total length of the genomes and g is the length of the longest genome. Baier et al. (Bioinformatics 32:497–504, 2016) improved their result.

Results

In this paper, we propose a new space-efficient representation of the compressed de Bruijn graph that adds the possibility to search for a pattern (e.g. an allele—a variant form of a gene) within the pan-genome. The ability to search within the pan-genome graph is of utmost importance and is a design goal of pan-genome data structures.

     

Survival of the exotic Chinese mystery snail (<Emphasis Type=Italic>Cipangopaludina chinensis malleata</Emphasis>) during air exposure and implications for overland dispersal by boats

The exotic Chinese mystery snail (Cipangopaludina chinensis malleata) has invaded lakes and rivers across North America and is particularly widespread in northern Wisconsin. Although deliberate introductions and aquarium releases have likely been important, recreational boats may speed the spread of this snail into lakes. Prior research indicated boater access to be a significant predictor of invasion by C. chinensis and other invasive species in Wisconsin. To mimic the process of boater transport between lakes, I examined the tolerance of juvenile C. chinensis to air exposure in a series of field and laboratory experiments. Field experiments under mesic conditions indicated that this snail can survive exposure to air for at least 4 weeks. Larger juveniles were more resistant than smaller juveniles, an effect that was also observed in the laboratory during short-term (3–14 days) experiments. Tolerance of small juveniles to air exposure appeared to be unaffected by temperature, but was affected by humidity, with higher survival at 64% than 34% relative humidity (RH). Results from the current study suggest that C. chinensis is highly resistant to air exposure and could be readily transported by boats moving between lakes, particularly in cool mesic environments. Since juvenile C. chinensis are common around the roots of emergent macrophytes, hitchhiking with boats should be particularly common with boats or trailers infested with aquatic plants.     

Assessing conditions influencing the longitudinal distribution of exotic brown trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) in a mountain stream: a spatially-explicit modeling approach

Trout species often segregate along elevational gradients, yet the mechanisms driving this pattern are not fully understood. On the Logan River, Utah, USA, exotic brown trout (Salmo trutta) dominate at low elevations but are near-absent from high elevations with native Bonneville cutthroat trout (Onchorhynchus clarkii utah). We used a spatially-explicit Bayesian modeling approach to evaluate how abiotic conditions (describing mechanisms related to temperature and physical habitat) as well as propagule pressure explained the distribution of brown trout in this system. Many covariates strongly explained redd abundance based on model performance and coefficient strength, including average annual temperature, average summer temperature, gravel availability, distance from a concentrated stocking area, and anchor ice-impeded distance from a concentrated stocking area. In contrast, covariates that exhibited low performance in models and/or a weak relationship to redd abundance included reach-average water depth, stocking intensity to the reach, average winter temperature, and number of days with anchor ice. Even if climate change creates more suitable summer temperature conditions for brown trout at high elevations, our findings suggest their success may be limited by other conditions. The potential role of anchor ice in limiting movement upstream is compelling considering evidence suggesting anchor ice prevalence on the Logan River has decreased significantly over the last several decades, likely in response to climatic changes. Further experimental and field research is needed to explore the role of anchor ice, spawning gravel availability, and locations of historical stocking in structuring brown trout distributions on the Logan River and elsewhere.     

Vertical Clinging and Leaping Revisited: Locomotion and Habitat Use in the Western Tarsier, <Emphasis Type=Italic>Tarsius bancanus</Emphasis> Explored Via Loglinear Modeling

Napier and Walker’s (1967) locomotor category of vertical clinging and leaping (VC&L) is one of the most familiar in primatology, and tarsiers are probably the most morphologically specialized of its membership. However, the link between vertical clinging and leaping remains unelucidated. We attempt to do so by reanalysis of Crompton’s 1985 and 1986 field observations of locomotion and habitat use in Tarsius bancanus, using loglinear modeling. Loglinear modeling is better suited to the categorical variables used in many field studies than more traditional statistics, such as ANOVA, developed for continuous variables. We show that climbing, as well as leaping, is one of the predominant forms of locomotion, and that all other things being equal, tarsiers tend to take off from, and land on, similar sized supports, which suggests that the following findings are not likely to be a result of substrate availability alone. Small body size lead to a prediction that tarsiers should leap down but climb up: this was not sustained: rather leaps tend to be level, and climbing accounts for more height loss than randomly expected. However, a prediction that to avoid energy loss to the substrate, the tarsiers should show a preference for large diameter supports for takeoff when leaping longer distances was supported, although tarsiers do not avoid moderately compliant supports. The prediction from ballistic principles that the longest leaps should start from high-angled supports was only weakly sustained, but low-angled supports tend to be strongly associated with short leaps, suggesting that such supports do not facilitate 45° takeoff trajectories. However, tarsiers displayed a preference for landing on medium-sized supports when leaping long distances, suggesting a preference for balancing the need for stability with minimizing musculoskeletal shock.     

Vaccination response to tetanus toxoid and 23-valent pneumococcal vaccines following administration of a single dose of abatacept: a randomized,open-label,parallel group study in healthy subjects

The effect of abatacept, a selective T-cell co-stimulation modulator, on vaccination has not been previously investigated. In this open-label, single-dose, randomized, parallel-group, controlled study, the effect of a single 750 mg infusion of abatacept on the antibody response to the intramuscular tetanus toxoid vaccine (primarily a memory response to a T-cell-dependent peptide antigen) and the intramuscular 23-valent pneumococcal vaccine (a less T-cell-dependent response to a polysaccharide antigen) was measured in 80 normal healthy volunteers. Subjects were uniformly randomized to receive one of four treatments: Group A (control group), subjects received vaccines on day 1 only; Group B, subjects received vaccines 2 weeks before abatacept; Group C, subjects received vaccines 2 weeks after abatacept; and Group D, subjects received vaccines 8 weeks after abatacept. Anti-tetanus and anti-pneumococcal (Danish serotypes 2, 6B, 8, 9V, 14, 19F and 23F) antibody titers were measured 14 and 28 days after vaccination. While there were no statistically significant differences between the dosing groups, geometric mean titers following tetanus or pneumococcal vaccination were generally lower in subjects who were vaccinated 2 weeks after receiving abatacept, compared with control subjects. A positive response (defined as a twofold increase in antibody titer from baseline) to tetanus vaccination at 28 days was seen, however, in ≥ 60% of subjects across all treatment groups versus 75% of control subjects. Similarly, over 70% of abatacept-treated subjects versus all control subjects (100%) responded to at least three pneumococcal serotypes, and approximately 25–30% of abatacept-treated subjects versus 45% of control subjects responded to at least six serotypes.     

Vectors,Hosts, and Control Measures for Zika Virus in the Americas

We examine Zika virus (ZIKV) from an ecological perspective and with a focus on the Americas. We assess (1) the role of wildlife in ZIKV disease ecology, (2) how mosquito behavior and biology influence disease dynamics, and (3) how nontarget species and ecosystems may be impacted by vector control programs. Our review suggests that free-ranging, non-human primates may be involved in ZIKV transmission in the Old World; however, other wildlife species likely play a limited role in maintaining or transmitting ZIKV. In the Americas, a zoonotic cycle has not yet been definitively established. Understanding behaviors and habitat tolerances of Aedes aegypti and Aedes albopictus, two ZIKV competent vectors in the Americas, will allow more accurate modeling of disease spread and facilitate targeted and effective control efforts. Vector control efforts may have direct and indirect impacts to wildlife, particularly invertebrate feeding species; however, strategies could be implemented to limit detrimental ecological effects.