Loads distributed in vivo among vertebrae,muscles, spinal ligaments,and intervertebral discs in a passively flexed lumbar spine

Biomechanics and Modeling in Mechanobiology - The load distribution among lumbar spinal structures—still an unanswered question—has been in the focus of this hybrid experimental and...     

Spruce sugars and poultry hydrolysate as growth medium in repeated fed-batch fermentation processes for production of yeast biomass

Bioprocess and Biosystems Engineering - The production of microbial protein in the form of yeast grown on lignocellulosic sugars and nitrogen-rich industrial residues is an attractive approach for...     

Early host–microbe interaction in a peri‐implant oral mucosa‐biofilm model

The host‐microbe relationship is pivotal for oral health as well as for peri‐implant diseases. Peri‐implant mucosa and commensal biofilm play important roles in the maintenance of host‐microbe homeostasis, but little is known about how they interact. We have therefore investigated the early host‐microbe interaction between commensal multispecies biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, Porphyromonas gingivalis) and organotypic peri‐implant mucosa using our three‐dimensional model. After 24 hr, biofilms induced weak inflammatory reaction in the peri‐implant mucosa by upregulation of five genes related to immune response and increased secretion of IL‐6 and CCL20. Biofilm volume was reduced which might be explained by secretion of β‐Defensins‐1, ‐2, and CCL20. The specific tissue reaction without intrinsic overreaction might contribute to intact mucosa. Thus, a relationship similar to homeostasis and oral health was established within the first 24 hr. In contrast, the mucosa was damaged and the bacterial distribution was altered after 48 hr. These were accompanied by an enhanced immune response with upregulation of additional inflammatory‐related genes and increased cytokine secretion. Thus, the homeostasis‐like relationship was disrupted. Such profound knowledge of the host‐microbe interaction at the peri‐implant site may provide the basis to improve strategies for prevention and therapy of peri‐implant diseases.     

Chromatin modifiers and recombination factors promote a telomere fold-back structure,that is lost during replicative senescence

Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C) approach to directly analyze telomere folding and its maintenance in S. cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a distinct telomeric chromatin environment is a major requirement for the folding of yeast telomeres. We demonstrate that telomeres are not folded when cells enter replicative senescence, which occurs independently of short telomere length. Indeed, Sir2, Sin3 and Set2 protein levels are decreased during senescence and their absence may thereby prevent telomere folding. Additionally, we show that the homologous recombination machinery, including the Rad51 and Rad52 proteins, as well as the checkpoint component Rad53 are essential for establishing the telomere fold-back structure. This study outlines a method to interrogate telomere-subtelomere interactions at a single unmodified yeast telomere. Using this method, we provide insights into how the spatial arrangement of the chromosome end structure is established and demonstrate that telomere folding is compromised throughout replicative senescence.     

Half a century of Scots pine forest ecosystem monitoring reveals long‐term effects of atmospheric deposition and climate change

At two forest sites in Germany (Pfaffenwinkel, Pustert) stocked with mature Scots pine (Pinus sylvestris L.), we investigated changes of topsoil chemistry during the recent 40 years by soil inventories conducted on replicated control plots of fertilization experiments, allowing a statistical analysis. Additionally, we monitored the nutritional status of both stands from 1964 until 2019 and quantified stand growth during the monitoring period by repeated stand inventories. Moreover, we monitored climate variables (air temperature and precipitation) and calculated annual climatic water balances from 1991 to 2019. Atmospheric nitrogen (N) and sulfur (S) deposition between 1964 and 2019 was estimated for the period 1969–2019 by combining annual deposition measurements conducted in 1985–1987 and 2004 with long‐term deposition records from long‐term forest monitoring stations. We investigated interrelations between topsoil chemistry, stand nutrition, stand growth, deposition, and climate trends. At both sites, the onset of the new millennium was a turning point of important biogeochemical processes. Topsoil acidification turned into re‐alkalinization, soil organic matter (SOM) accumulation stopped, and likely turned into SOM depletion. In the new millennium, topsoil stocks of S and plant‐available phosphorus (P) as well as S and P concentrations in Scots pine foliage decreased substantially; yet, age‐referenced stand growth remained at levels far above those expected from yield table data. Tree P and S nutrition as well as climate change (increased temperature and drought stress) have replaced soil acidification as major future challenges for both forests. Understanding of P and S cycling and water fluxes in forest ecosystems, and consideration of these issues in forest management is important for successfully tackling the new challenges. Our study illustrates the importance of long‐term forest monitoring to identify slow, but substantial changes of forest biogeochemistry driven by natural and anthropogenic global change.     

Distribution of Sprattus sprattus phalericus (Risso, 1827) and zooplankton near the Black Sea redoxcline

Understanding what environmental drivers influence marine predator–prey relationships can be key to managing and protecting ecosystems, especially in the face of future climate change risks. This is especially important in environments such as the Black Sea, where strong biogeochemical gradients can drive marine habitat partitioning and ecological interactions. We used underwater video recordings in the north-eastern Black Sea in November 2013 to observe the distribution and behaviour of the Black Sea sprat (Sprattus sprattus phalericus, Risso 1827) and its zooplankton prey. Video recordings have shown that the Black Sea sprat S. sprattus phalericus tolerates severely hypoxic waters near the redoxcline. The school was distributed in the 33–96 m layer [oxygen concentration (O₂) 277–84 μmol L⁻¹]. Some individuals were observed to leave the school and descended 20 m deeper for foraging on copepods in the 119–123 m layer (O₂ 12–10 μmol L⁻¹). Zooplankton appeared concentrated on the upper boundary of the suboxic zone (O₂ < 10 μmol L⁻¹). No zooplankton were observed below O₂ 6–7 μmol L⁻¹ (128 m). Understanding the ability of this species to tolerate low oxygen waters is crucial to predicting future responses to natural and anthropogenic changes in hypoxia.     

Improvement in efficiency of microspore culture to produce doubled haploid lines of Ethiopian mustard

Factors affecting microspore embryogenesis of Ethiopian mustard (Brassica carinata A. Braun) were evaluated, including flower bud length, pollen developmental stage, and microspore density. An embryogenic frequency of 300 embryos per Petri plate was observed with NLN (Nitsch-Lichter-Nitsch) medium supplemented with 13% sucrose, 3.0–3.4-mm-long buds, and a plating density of 65,000 microspores/ml. About 65% of the microspores from buds 3.0–3.4-mm long were at the late uninucleate stage. Microspore-derived embryos were successfully transferred to solid medium for germination. After 4 wk, the resulting plantlets were transplanted to a soilless potting mixture and grew well under greenhouse conditions.     

Lumbar posture and muscular activity while sitting during office work

PurposeField study, cross-sectional study to measure the posture and sEMG of the lumbar spine during office work for a better understanding of the lumbar spine within such conditions.ScopeThere is high incidence of low back pain in office workers. Currently there is little information about lumbar posture and the activity of lumbar muscles during extended office work.MethodsThirteen volunteers were examined for around 2 h of their normal office work. Typical tasks were documented and synchronised to a portable long term measuring device for sEMG and posture examination. The correlation of lumbar spine posture and sEMG was tested statistically.ResultsThe majority of time spent in office work was sedentary (82%). Only 5% of the measured time was undertaken in erect body position (standing or walking). The sEMG of the lumbar muscles under investigation was task dependent. A strong relation to lumbar spine posture was found within each task. The more the lumbar spine was flexed, the less there was activation of lumbar muscles (P < .01). Periods of very low or no activation of lumbar muscles accounted for about 30% of relaxed sitting postures.ConclusionBecause of very low activation of lumbar muscles while sitting, the load is transmitted by passive structures like ligaments and intervertebral discs. Due to the viscoelasticity of passive structures and low activation of lumbar muscles, the lumbar spine may incline into de-conditioning. This may be a reason for low back pain.