bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unleashing Natural Competence in Lactococcus lactis by Induction of the Competence Regulator ComX
Authors: Mulder Joyce , Wels Michiel , Kuipers Oscar P. , Kleerebezem Michiel , Bron Peter A. 
Published: August 2017

ABSTRACT

In biotechnological workhorses like
Streptococcus thermophilus
and
Bacillus subtilis
, natural competence can be induced, which facilitates genetic manipulation of these microbes. However, in strains of the important dairy starter
Lactococcus lactis
, natural competence has not been established to date. However,
in silico
analysis of the complete genome sequences of 43
L. lactis
strains revealed complete late competence gene sets in 2
L. lactis
subsp.
cremoris
strains (KW2 and KW10) and at least 10
L. lactis
subsp.
lactis
strains, including the model strain IL1403 and the plant-derived strain KF147. The remainder of the strains, including all dairy isolates, displayed genomic decay in one or more of the late competence genes. Nisin-controlled expression of the competence regulator
comX
in
L. lactis
subsp.
lactis
KF147 resulted in the induction of expression of the canonical competence regulon and elicited a state of natural competence in this strain. In contrast,
comX
expression in
L. lactis
NZ9000, which was predicted to encode an incomplete competence gene set, failed to induce natural competence. Moreover, mutagenesis of the
comEA-EC
operon in strain KF147 abolished the
comX
-driven natural competence, underlining the involvement of the competence machinery. Finally, introduction of nisin-inducible
comX
expression into
nisRK
-harboring derivatives of strains IL1403 and KW2 allowed the induction of natural competence in these strains also, expanding this phenotype to other
L. lactis
strains of both subspecies.

IMPORTANCE
Specific bacterial species are able to enter a state of natural competence in which DNA is taken up from the environment, allowing the introduction of novel traits. Strains of the species
Lactococcus lactis
are very important starter cultures for the fermentation of milk in the cheese production process, where these bacteria contribute to the flavor and texture of the end product. The activation of natural competence in this industrially relevant organism can accelerate research aiming to understand industrially relevant traits of these bacteria and can facilitate engineering strategies to harness the natural biodiversity of the species in optimized starter strains.
Induction of Shiga Toxin-Encoding Prophage by Abiotic Environmental Stress in Food
Authors: Fang Yuan , Mercer Ryan G. , McMullen Lynn M. , Gänzle Michael G. 
Published: August 2017

ABSTRACT

The prophage-encoded Shiga toxin is a major virulence factor in Stx-producing
Escherichia coli
(STEC). Toxin production and phage production are linked and occur after induction of the RecA-dependent SOS response. However, food-related stress and Stx-prophage induction have not been studied at the single-cell level. This study investigated the effects of abiotic environmental stress on
stx
expression by single-cell quantification of gene expression in STEC O104:H4 Δ
stx2
::
gfp
::
amp

r

. In addition, the effect of stress on production of phage particles was determined. The lethality of stressors, including heat, HCl, lactic acid, hydrogen peroxide, and high hydrostatic pressure, was selected to reduce cell counts by 1 to 2 log CFU/ml. The integrity of the bacterial membrane after exposure to stress was measured by propidium iodide (PI). The fluorescent signals of green fluorescent protein (GFP) and PI were quantified by flow cytometry. The mechanism of prophage induction by stress was evaluated by relative gene expression of
recA
and cell morphology. Acid (pH < 3.5) and H
2
O
2
(2.5 mM) induced the expression of
stx
2
in about 18% and 3% of the population, respectively. The mechanism of prophage induction by acid differs from that of induction by H
2
O
2
. H
2
O
2
induction but not acid induction corresponded to production of infectious phage particles, upregulation of
recA
, and cell filamentation. Pressure (200 MPa) or heat did not induce the Stx2-encoding prophage (Stx2-prophage). Overall, the quantification method developed in this study allowed investigation of prophage induction and physiological properties at the single-cell level. H
2
O
2
and acids mediate different pathways to induce Stx2-prophage.

IMPORTANCE
Induction of the Stx-prophage in STEC results in production of phage particles and Stx and thus relates to virulence as well as the transduction of virulence genes. This study developed a method for a detection of the induction of Stx-prophages at the single-cell level; membrane permeability and an indication of SOS response to environmental stress were additionally assessed. H
2
O
2
and mitomycin C induced expression of the prophage and activated a SOS response. In contrast, HCl and lactic acid induced the Stx-prophage but not the SOS response. The lifestyle of STEC exposes the organism to intestinal and extraintestinal environments that impose oxidative and acid stress. A more thorough understanding of the influence of food processing-related stressors on Stx-prophage expression thus facilitates control of STEC in food systems by minimizing prophage induction during food production and storage.
Constant Flux of Spatial Niche Partitioning through High-Resolution Sampling of Magnetotactic Bacteria
Authors: He Kuang , Gilder Stuart A. , Orsi William D. , Zhao Xiangyu , Petersen Nikolai 
Published: August 2017

ABSTRACT

Magnetotactic bacteria (MTB) swim along magnetic field lines in water. They are found in aquatic habitats throughout the world, yet knowledge of their spatial and temporal distribution remains limited. To help remedy this, we took MTB-bearing sediment from a natural pond, mixed the thoroughly homogenized sediment into two replicate aquaria, and then counted three dominant MTB morphotypes (coccus, spirillum, and rod-shaped MTB cells) at a high spatiotemporal sampling resolution: 36 discrete points in replicate aquaria were sampled every ∼30 days over 198 days. Population centers of the MTB coccus and MTB spirillum morphotypes moved in continual flux, yet they consistently inhabited separate locations, displaying significant anticorrelation. Rod-shaped MTB were initially concentrated toward the northern end of the aquaria, but at the end of the experiment, they were most densely populated toward the south. The finding that the total number of MTB cells increased over time during the experiment argues that population reorganization arose from relative changes in cell division and death and not from migration. The maximum net growth rates were 10, 3, and 1 doublings day
−1
and average net growth rates were 0.24, 0.11, and 0.02 doublings day
−1
for MTB cocci, MTB spirilla, and rod-shaped MTB, respectively; minimum growth rates for all three morphotypes were −0.03 doublings day
−1
. Our results suggest that MTB cocci and MTB spirilla occupy distinctly different niches: their horizontal positioning in sediment is anticorrelated and under constant flux.

IMPORTANCE
Little is known about the horizontal distribution of magnetotactic bacteria in sediment or how the distribution changes over time. We therefore measured three dominant magnetotactic bacterium morphotypes at 36 places in two replicate aquaria each month for 7 months. We found that the spatial positioning of population centers changed over time and that the two most abundant morphotypes (MTB cocci and MTB spirilla) occupied distinctly different niches in the aquaria. Maximum and average growth and death rates were quantified for each of the three morphotypes based on 72 sites that were measured six times. The findings provided novel insight into the differential behavior of noncultured magnetotactic bacteria.
A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family
Authors: Andberg Martina , Mollerup Filip , Parikka Kirsti , Koutaniemi Sanna , Boer Harry , Juvonen Minna , Master Emma , Tenkanen Maija , Kruus Kristiina 
Published: August 2017

ABSTRACT

We describe here the identification and characterization of a copper radical oxidase from auxiliary activities family 5 (AA5_2) that was distinguished by showing preferential activity toward raffinose. Despite the biotechnological potential of carbohydrate oxidases from family AA5, very few members have been characterized. The gene encoding raffinose oxidase from
Colletotrichum graminicola
(
Cg
RaOx; EC 1.1.3.−) was identified utilizing a bioinformatics approach based on the known modular structure of a characterized AA5_2 galactose oxidase.
Cg
RaOx was expressed in
Pichia pastoris
, and the purified enzyme displayed the highest activity on the trisaccharide raffinose, whereas the activity on the disaccharide melibiose was three times lower and more than ten times lower activity was detected on
d
-galactose at a 300 mM substrate concentration. Thus, the substrate preference of
Cg
RaOx was distinguished clearly from the substrate preferences of the known galactose oxidases. The site of oxidation for raffinose was studied by
1
H nuclear magnetic resonance and mass spectrometry, and we confirmed that the hydroxyl group at the C-6 position was oxidized to an aldehyde and that in addition uronic acid was produced as a side product. A new electrospray ionization mass spectrometry method for the identification of C-6 oxidized products was developed, and the formation mechanism of the uronic acid was studied.
Cg
RaOx presented a novel activity pattern in the AA5 family.

IMPORTANCE
Currently, there are only a few characterized members of the CAZy AA5 protein family. These enzymes are interesting from an application point of view because of their ability to utilize the cheap and abundant oxidant O
2
without the requirement of complex cofactors such as FAD or NAD(P). Here, we present the identification and characterization of a novel AA5 member from
Colletotrichum graminicola
. As discussed in the present study, the bioinformatics approach using the modular structure of galactose oxidase was successful in finding a C-6 hydroxyl carbohydrate oxidase having substrate preference for the trisaccharide raffinose. By the discovery of this activity, the diversity of the CAZy AA5 family is increasing.
Neovascular age-related macular degeneration management in the third year: final results from the TREX-AMD randomised trial
Authors: Wykoff Charles C , Ou William C , Croft Daniel E , Payne John F , Brown David M , Clark W Lloyd , Abdelfattah Nizar Saleh , Sadda SriniVas R 
Published: August 2017

Background/AimsProspectively evaluate outcomes in the third year of neovascular age-related macular degeneration (AMD) management using ranibizumab with continued treat and extend (TREX) dosing compared with monthly visits with retreatment upon evidence of exudative disease activity (PRN, pro re nata).MethodsSubjects with treatment-naïve neovascular AMD were randomised 1:2 to Monthly or TREX and managed through 2 years. In the third year, subjects randomised to Monthly were managed PRN while subjects randomised to TREX were continued on TREX dosing or transitioned to PRN after achieving an interval of 12 weeks between visits.ResultsSixty subjects enrolled and 46 (77%) completed month 36 (M36). Transition from Monthly to PRN was associated with a decline in best corrected visual acuity (BCVA) (+10.5 letters (month 24) to +5.4 (M36, p=0.09)); three (15%) subjects required no dosing during year 3, and 47% (114/243) of possible PRN injections were delivered, yielding a mean of 6.1 injections during year 3. Among the 9 (23%) TREX subjects transitioned to PRN, the need for ongoing anti-vascular endothelial growth factor retreatments was small, with 4 (4%) intravitreal injections being delivered among 106 PRN visits; this subgroup displayed an inferior BCVA trajectory compared with the remainder of subjects. Outcomes among subjects continued on TREX were more favourable, with a mean gain of +5.0 letters at M36.ConclusionsUpon transition to PRN, subjects randomised to monthly dosing experienced a decline in BCVA. Among subjects initially randomised to TREX who transitioned to PRN after achieving a 12-week interval between visits, the overall need for additional treatment was low.Trial registration numberNCT01748292, Results.
INCIDENCE OF ACUTE TRAUMATIC INJURIES AND MEDICAL COMPLICATIONS IN 34 033 CYCLISTS PARTICIPATING IN A MASS COMMUNITY BASED EVENT – SAFER CYCLING
Authors: Killops Jannelene , Schwellnus Martin , van Rensburg Dina Christina Janse 
Published: August 2017

BackgroundMass participation in recreational sport (such as cycling) is part of a healthy lifestyle, and is an important component in the primary and secondary prevention of non-communicable diseases (NCD's). However, there is a risk of acute traumatic injuries and acute medical complications during community mass participation cycling races, but this has not been well documented.ObjectiveThe objective of this study was to document the incidence of acute traumatic injuries and acute non-traumatic medical complications in a community mass participation cycling race.DesignRetrospective cohort study.Setting109 km cycling race.ParticipantsAll 34 033 race starters (males=26 835, females=7 198) to the 2014 Cape Town Cycle Tournament.AssessmentPre-race entry demographic data and race-day medical complications data (all incidents that required assessment by the medical team on race day) were collected.Main Outcome MeasurementsThe incidence (per 1000 race starters) of all complications, acute traumatic injuries and non-traumatic medical complications and serious life threatening complications were determined for all cyclists, and male and female cyclists.ResultsThe incidence (per 1000 starters) of all complications was 6.35, and this was significantly higher in females vs. males (male=5.78, female=8.47; p=0.014). The incidence of serious life-threatening complications was 0.5, and there was a trend toward a higher incidence in female cyclists (female=0.97, males=0.37; p=0.06). Female cyclists also had a significantly higher (p=0.027) incidence of acute traumatic injuries (females=6.53, males=4.47; p=0.027). The incidence of acute non-traumatic medical complications was 1.44 (males=1.30, females=1.94; p=0.203).Conclusions1/157 race starters (males: 1/173; females: 1/118) at a community based cycling event were injured or developed a medical complication during the race, and the risk is significantly higher in female cyclists. These data indicate the need to develop and implement prevention strategies to reduce the risk of medical complications, specifically traumatic injuries, in female cyclists.
INJURIES IN ELITE AUSTRALIAN FEMALE CRICKETERS
Authors: Perera Nirmala , Kountouris Alex , Kemp Joanne , Joseph Corey , Finch Caroline 
Published: August 2017

BackgroundCricket Australia has a well-established injury surveillance program for its elite male players and has published regular reports. Whilst injury data has been collected for the elite female players, it has not been published to date.ObjectiveTo establish injury profiles sustained by elite female players by utilising the data collected through the Cricket Australia's Athlete Management System.DesignCohort study, 2014–16 seasons.SettingInternational and national cricket.ParticipantsElite women.Main Outcome MeasurementsIncidence, nature and anatomical location and mechanism of injuries.ResultsThe mean age of the 121 players was 24.2 years (SD ±4.5). 113 players sustained 600 injuries; 77.7% (n=94) sustained ≥1 injury. 477 injuries (79.5%) were acute and 73.2% (n=439) were new. Injury match incidence was 424.7 injuries/10,000 hours for all injuries, and 79.3 injuries/10,000 hours for time-loss. Thigh (n=84, 14.0%), wrist (n=77, 12.8%), knee (n=68, 11.3%), shoulder (n=66, 11.0%) and lumbar spine (n=63, 10.5%) were the most frequently injured regions. There were 31.8% (n=191) muscle injuries; 16.0% (n=96) joint sprains. Most injuries occurred via an insidious onset (28.7%, n=172), with running 15.3% (n=92) the most common mechanism. There were 121 (20.2%) time-loss injuries (94 new and 27 recurrent) resulting total of 3638 days (average 30 days, SD ±47.38) away from the sport. Wrist/hand (n=20, 19.80%) and lumbar spine (n=20, 16.5) were the most common time-loss injuries. Six players sustained lumbar-spine stress fractures that resulted in the most days missed due to injury (average 111 days/injury).ConclusionsSimilarities are evident between male and female cricket injury profiles with the thigh being the most injured location. This is the first study to demonstrate that elite female cricket players also develop lumbar spine stress fractures, similar to their male counterparts. More research is required to determine the mechanisms for injuries in female players.
THE EFFECT OF RUNNING NINE MARATHONS IN NINE DAYS ON PROPRIOCEPTION AND BALANCE
Authors: Relph Nicola , Small Katie , Smith Adam 
Published: August 2017

BackgroundMulti-day running events are becoming increasingly popular with nonprofessional athletes. However, it is unknown how and when this type of event affects injury risk factors such as proprioception and balance.ObjectiveTo evaluate the effect of running one, five consecutive and nine consecutive marathons on joint position sense (JPS) and dynamic balance.DesignCross-sectional, observational study.SettingSports-injury clinic.Participants21 athletes completing the event (age 44.8±8.09 yrs, mass 74.4±13.14 kg, years running 10.4±7.39 yrs, average weekly mileage 44.8±12.09 miles) entered the study. Ten athletes completed the JPS testing and five athletes completed the dynamic balance testing.Assessment of Risk FactorsRisk factors were assessed the day before the event (day zero) and then following completion of one (day one), five (day five) and nine (day nine) consecutive marathons. The independent variable was time.Main Outcome MeasurementsJPS error into flexion and extension, star-excursion balance test (SEBT) and number of injuries per runner.ResultsFriedman's ANOVAs indicated no effects of time on JPS into extension (p=0.94), dominant-leg anterior (p=0.52) or posterior-lateral (p=0.65) SEBT reach. JPS flexion error significantly decreased by 1.3° from day one to five (p=0.032). Non-dominant leg anterior, posterior-medial and posterior-lateral SEBT reaches significantly decreased from day zero to nine by 0.09% (p=0.043), 0.13% (p=0.043) and 0.17% (p=0.043) of leg length respectively. Dominant leg posterior-medial SEBT reach also significantly decreased by 0.12% of leg length (p=0.043) from day zero to nine. There were 4.2 injuries per runner.ConclusionsThe results suggest multi-day running events can cause over four lower limb injuries per runner and reduce dynamic balance ability. Nonprofessional athletes completing these events should be aware of this high injury occurrence and prepare appropriately. Injury prevention programmes incorporating dynamic balance may be recommended. However future studies with additional risk factors and larger sample sizes are needed to substantiate these findings.
FUNCTIONAL MOVEMENT SCREEN AND LOWER LIMB STRENGTH ASYMMETRY IN PROFESSIONAL SOCCER PLAYERS
Authors: Sannicandro Italo , Cofano Giacomo , Rosa Anna Rosa , Traficante Paolo , Piccinno Andrea 
Published: August 2017

BackgroundThe Functional Movement Screen (FMS) protocol consists of 7 tests (Cook & Burton, 2014). At higher values mean higher quality of movement execution. Lower limb functional asymmetry (FA) is monitored to control the athlete's injury risk (Sannicandroet al., 2011).ObjectiveTo examine the correlation between the FMS score and strength asymmetry in professional soccer players (PSP).DesignDescriptive study (correlation study investigating the relationship between variables).SettingProfessional soccer.Participantsn=30 professional soccer players (age: 22.2±4.6; weight: 74.3±10,1 kg; height: 176.1±8.7 cm), 4 players were excluded due to joint or muscle injury within the last 18 months.Assessment of Risk FactorsThe FMS protocol identifies athletes as being at risk of injury when the total score is ≤14. The Hop Test (HT), Side Hop (SH) and Hop Crossover (CH) test are considered to represent a valid assessment of the single lower limb FA. The counter movement jump (CMJ) test indirectly evaluates explosive strength capacity (jump height).Main Outcome MeasurementsThe sample was evaluated using the 7 FMS test and CMJ, HT, SH and CH tests for strength capacity. FA was calculated between the two limbs as follows: (jump dominant limb–jump non-dominant limb)/jump dominant-limb*100 (Yamamoto, 1993).ResultsWe observed a significant inverse correlation between FMS score and the SH asymmetry percentage (r=−0.678, p<0.01) and the CH asymmetry percentage (r=−0.572,p<0.01). We also observed a significant positive correlation between the FMS score and CMJ values (r=0.531, p<0.01). No significant correlation was found between FMS and the HT asymmetry percentage (r=−0.245).ConclusionsThe best quality movement in FMS test was correlated with high performance in CMJ and with low percentage of lower limb FA, respectively.
INTRINSIC AND EXTRINSIC INJURY RISK FACTORS OF ELITE WINTER SPORTS ATHLETE IN TRAINING
Authors: Wang Victor , Mayer Frank , Bonaventura Klaus , Wippert Maria 
Published: August 2017

BackgroundMulti-factorial sport injury related models are well accepted for sport medicine scientists and experts. However, injury risk factors research involved with winter sport athletes seems not well documented due to its complicated, interactive intrinsic and extrinsic factors.ObjectiveTo exam the significant difference and correlation relationships between injury outcomes and winter sport elite athletes' intrinsic and extrinsic risk factors.Design and SettingA cross-section and retrospective risk of injury questionnaire (Risk-IQ) designed for elite athlete in training period was employed. Currently active and retired national delegation athletes of Olympic winter sports were recruited.Participants34 winter Olympic sport elite athletes (f/m 13/21 age=28.9+-7.7) were recruited from national sport training centres, sport federations and universities fron both Germany and Taiwan.Assessment of Risk FactorsPotential risk for athletic accumulated injuries were assessed through 6 intrinsic (age, gender, experience, stress, cardiovascular problems and importance of risk screening) and 6 extrinsic (nation, sport type, training environment, periodic health examination(PHE)/preparticipation evaluation (PPE), physical complains, medical care support) factors. Kruskal-Wallis test, Mann-Whitney U test and Spearmann correlation test were used.Main Outcome MeasurementsThe total sport training related injury incidences were planned as outcome measurements. The adapted intrinsic and extrinsic injury related risk factors were tested for significance difference and correlations.ResultsSignificant results were found in intrinsic factors: age (10 body-part p<0.01; back & chest p<0.01; shoulder & arm p<0.01, elbow & hand p<0.01; hip & thigh p<0.01; knee p<0.05), stress level (knee r=0.348 p<0.05, foot & toe r=0.404 p<0.05); in extrinsic factors: nation (p<0.01), sport type(Olympic), PHE screen(back p<0.05, physical complain on knee(r=0.355, p<0.05l leg & ankle r=0.487 p<0.01) and foot (elbow & hand r=0.386, p<0.05).ConclusionsSome factors showed their significant results with body-part specificity (only some body-parts but not others) which deserved further detailed investigation with greater subject population.