A Unique Regulator Contributes to Quorum Sensing and Virulence in Burkholderia cenocepacia

Burkholderia cenocepacia causes chronic and life-threatening respiratory infections in immunocompromized people. The B. cenocepacia N-acyl-homoserine lactone (AHL)-dependent quorum sensing system relies on the production of AHLs by the synthases CepI and CciI while CepR, CciR and CepR2 control expression of many genes important for pathogenesis. Downstream from, and co-transcribed with cepI, lies BCAM1871 encoding a hypothetical protein that was uncharacterized prior to this study. Orthologs of B. cenocepacia BCAM1871 are uniquely found in Burkholderia spp and are conserved in their genomic locations in pathogenic Burkholderia. We observed significant effects on AHL activity upon mutation or overexpression of BCAM1871, although these effects were more subtle than those observed for CepI indicating BCAM1871 acts as an enhancer of AHL activity. Transcription of cepI, cepR and cciIR was significantly reduced in the BCAM1871 mutant. Swimming and swarming motilities as well as transcription of fliC, encoding flagellin, were significantly reduced in the BCAM1871 mutant. Protease activity and transcription of zmpA and zmpB, encoding extracellular zinc metalloproteases, were undetectable in the BCAM1871 mutant indicating a more significant effect of mutating BCAM1871 than cepI. Exogenous addition of OHL restored cepI, cepR and fliC transcription but had no effect on motility, protease activity or zmpA or zmpB transcription suggesting AHL-independent effects. The BCAM1871 mutant exhibited significantly reduced virulence in rat chronic respiratory and nematode infection models. Gene expression and phenotypic assays as well as vertebrate and invertebrate infection models showed that BCAM1871 significantly contributes to pathogenesis in B. cenocepacia

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

Earthworm invasion into previously earthworm-free temperate and boreal forests

Earthworms are keystone detritivores that can influence primary producers by changing seedbed conditions, soil characteristics, flow of water, nutrients and carbon, and plant–herbivore interactions. The invasion of European earthworms into previously earthworm-free temperate and boreal forests of North America dominated by Acer, Quercus, Betula, Pinus and Populus has provided ample opportunity to observe how earthworms engineer ecosystems. Impacts vary with soil parent material, land use history, and assemblage of invading earthworm species. Earthworms reduce the thickness of organic layers, increase the bulk density of soils and incorporate litter and humus materials into deeper horizons of the soil profile, thereby affecting the whole soil food web and the above ground plant community. Mixing of organic and mineral materials turns mor into mull humus which significantly changes the distribution and community composition of the soil microflora and seedbed conditions for vascular plants. In some forests earthworm invasion leads to reduced availability and increased leaching of N and P in soil horizons where most fine roots are concentrated. Earthworms can contribute to a forest decline syndrome, and forest herbs in the genera Aralia, Botrychium, Osmorhiza, Trillium, Uvularia, and Viola are reduced in abundance during earthworm invasion. The degree of plant recovery after invasion varies greatly among sites and depends on complex interactions with soil processes and herbivores. These changes are likely to alter competitive relationships among plant species, possibly facilitating invasion of exotic plant species such as Rhamnus cathartica into North American forests, leading to as yet unknown changes in successional trajectory

Порівняння максимального поглинання кисню і анаеробного порога у футболістів і гандболістів

Ackground/Objective: The purpose of this study was to compare maximal oxygen uptake and anaerobic threshold values between soccer and handball players. Methods: 10 male professional soccer players and 10 male professional handball players took part in the study. Maximal oxygen uptake (VO2max) and anaerobic threshold (AT) were assessed using an incremental treadmill test. AT was estimated noninvasively using the V-slope method. The values of VO2 (ATVO2), heart rate (ATHR), time (ATTIME) and running speed (ATSPEED) corresponding to the AT were identified. AT was recorded as a percentage of VO2max (AT %VO2max) and HRmax (AT %HRmax). Time to exhaustion was determined as the total duration of the test. Results: There were no significant difference between the time to exhaustion(min), HRmax, absolute VO2max (ml min-1) and relative VO2max (ml kg-1min-1) of soccer and handball players compared to each other (p> 0.05). Similarly there were no significant difference between the two groups in the ATSPEED (km h-1), ATTIME (min), ATHR, absolute ATVO2 (ml min-1), relative ATVO2 (ml kg-1min-1), AT %VO2max and AT %HRmax (P> 0.05). Conclusion: Although soccer and handball require different movement patterns, they may exhibit similar aerobic endurance capacity. Hence physiological requirements in both branches may be expected to be similar in relation to training volume and intensity.Цель . Целью этого исследования было сравнить максимальное поглощение кислорода и анаэробные пороговые значения между футболистами и гандболистами. Материал : 10 мужчин профессиональных футболистов и 10 мужчин профессиональных гандболистов приняли участие в исследовании. Максимальное поглощение кислорода (VO2max) и анаэробный порог (AT) оценивали с использованием инкрементного теста беговой дорожки. AT оценивали неинвазивно с использованием метода V-наклона. Определены значения VO2 (ATVO2), частоты сердечных сокращений (ATHR), времени (ATTIME) и скорости движения (ATSPEED), соответствующих AT. AT регистрировали в процентах от VO2max (AT% VO2max) и HRmax (AT% HRmax). Время исчерпания определяли как общую продолжительность теста. Результаты : не было существенной разницы между временем истощения (мин), HRmax, абсолютным VO2max (мл мин-1) и относительным VO2max (мл кг-1 мин-1) футболистов и гандболистов по сравнению друг с другом (p> 0,05 ). Аналогичным образом не было существенной разницы между двумя группами в ATSPEED (км h-1), ATTIME (мин), ATHR, абсолютным ATVO2 (мл мин-1), относительным ATVO2 (мл кг-1 мин-1), AT% VO2max И AT% HRmax (P> 0,05). Выводы : хотя футбол и гандбол требуют разных моделей движения, они могут проявлять сходную аэробную выносливость. Следовательно, можно ожидать, что физиологические требования в обеих ветвях будут одинаковыми по отношению к объему и интенсивности тренировки.Мета . Метою цього дослідження було порівняти максимальне поглинання кисню і анаеробні порогові значення між футболістами і гандболістами. Матеріал : 10 чоловіків професійних футболістів і 10 чоловіків професійних гандболістів взяли участь в дослідженні. Максимальне поглинання кисню (VO2max) і анаеробний поріг (AT) оцінювали з використанням інкрементного тесту бігової доріжки. AT оцінювали неінвазивно з використанням методу V-нахилу. Визначено значення VO2 (ATVO2), частоти серцевих скорочень (ATHR), часу (ATTIME) і швидкості руху (ATSPEED), відповідних AT. AT реєстрували у відсотках від VO2max (AT% VO2max) і HRmax (AT% HRmax). Час вичерпання визначали як загальну тривалість тесту. Результати: не було суттєвої різниці між часом виснаження (хв), HRmax, абсолютним VO2max (мл хв-1) і відносним VO2max (мл кг-1 хв-1) футболістів і гандболістів в порівнянні один з одним (p> 0,05) . Аналогічним чином не було суттєвої різниці між двома групами в ATSPEED (км h-1), ATTIME (хв), ATHR, абсолютним ATVO2 (мл хв-1), відносним ATVO2 (мл кг-1 хв-1), AT% VO2max І AT% HRmax (P> 0,05). Висновки : хоча футбол і гандбол вимагають різних моделей руху, вони можуть проявляти подібну аеробну витривалість. Отже, можна очікувати, що фізіологічні вимоги в обох гілках будуть однаковими по відношенню до обсягу і інтенсивності тренування

A Molecular Survey of S. Mutans and P. Gingivalis Oral Microbial Burden in Human Saliva Using Relative Endpoint Polymerase Chain Reaction (RE-PCR) within the Population of a Nevada Dental School Revealed Disparities among Minorities

Background: The University of Nevada, Las Vegas School of Dental Medicine recently opened an orthodontic treatment clinic to address the needs of the racially and ethnically diverse population of Southern Nevada, primarily focusing on the treatment and care of low-income and minority patients. Although orthodontic treatment and therapy has been shown to induce changes in the oral cavity, much of this evidence was collected from traditional White, teenage orthodontic clinic populations. The primary goal of this study was to describe the microbial burden of the cariogenic and periodontal pathogens, Streptococcus mutans and Porphyromonas gingivalis within the UNLV-SDM patient population.Methods: Representative saliva samples were collected from healthy adult patients for DNA isolation. Relative endpoint polymerase chain reaction (RE-PCR) was performed to ascertain the presence and relative microbial burden of these oral pathogens.Results: Nearly one quarter (13/56) or 23.3% of these patients had elevated levels of S. mutans, while (10/56) and 17.8% of these samples were found to have elevated levels of P. gingivalis, - with (90%) of P. gingivalis-positive samples from minority patients (X-2 = 17.921, d.f. = 1; p \u3c 0.0001).Conclusions: These findings of elevated P. gingivalis levels, primarily among minority patients, may suggest underlying oral health practices contributing to adverse oral health conditions within this population. Oral health knowledge and practices among minority patients may be strongly influenced by other factors, including education and socioeconomic status, suggesting additional research may be needed to accurately determine the most appropriate standards for care and oral health education within this patient population