Degradation of Bio-Based and Biodegradable Plastic and Its Contribution to Soil Organic Carbon Stock.

Expanding the use of environmentally friendly materials to protect the environment is one of the key factors in maintaining a sustainable ecological balance. Poly(butylene succinate-co-adipate) (PBSA) is considered among the most promising bio-based and biodegradable plastics for the future with a high number of applications in soil and agriculture. Therefore, the decomposition process of PBSA and its consequences for the carbon stored in soil require careful monitoring. For the first time, the stable isotope technique was applied in the current study to partitioning plastic- and soil-originated C in the CO2 released during 80 days of PBSA decomposition in a Haplic Chernozem soil as dependent on nitrogen availability. The decomposition of the plastic was accompanied by the C loss from soil organic matter (SOM) through priming, which in turn was dependent on added N. Nitrogen facilitated PBSA decomposition and reduced the priming effect during the first 6 weeks of the experiment. During the 80 days of plastic decomposition, 30% and 49% of the released CO2 were PBSA-derived, while the amount of SOM-derived CO2 exceeded the corresponding controls by 100.2 and 132.3% in PBSA-amended soil without and with N fertilization, respectively. Finally, only 4.1% and 5.4% of the PBSA added into the soil was mineralized to CO2, in the treatments without and with N amendment, respectively.

Links among Microbial Communities, Soil Properties and Functions: Are Fungi the Sole Players in Decomposition of Bio-Based and Biodegradable Plastic?

The incomplete degradation of bio-based and biodegradable plastics (BBPs) in soils causes multiple threats to soil quality, human health, and food security. Plastic residuals can interact with soil microbial communities. We aimed to link the structure and enzyme-mediated functional traits of a microbial community composition that were present during poly (butylene succinate-co-butylene adipate (PBSA) decomposition in soil with (PSN) and without (PS) the addition of nitrogen fertilizer ((NH4)2SO4). We identified bacterial (Achromobacter, Luteimonas, Rhodanobacter, and Lysobacter) and fungal (Fusarium, Chaetomium, Clonostachys, Fusicolla, and Acremonium) taxa that were linked to the activities of ß-glucosidase, chitinase, phosphatase, and lipase in plastic-amended soils. Fungal biomass increased by 1.7 and 4 times in PS and PSN treatment, respectively, as compared to non-plastic amended soil. PBSA significantly changed the relationships between soil properties (C: N ratio, TN, and pH) and microbial community structure; however, the relationships between fungal biomass and soil enzyme activities remained constant. PBSA significantly altered the relationship between fungal biomass and acid phosphatase. We demonstrated that although the soil functions related to nutrient cycling were not negatively affected in PSN treatment, potential negative effects are reasoned by the enrichment of plant pathogens. We concluded that in comparison to fungi, the bacteria demonstrated a broader functional spectrum in the BBP degradation process.

Nitrogen fixing bacteria facilitate microbial biodegradation of a bio-based and biodegradable plastic in soils under ambient and future climatic conditions.

We discovered a biological mechanism supporting microbial degradation of bio-based poly(butylene succinate-co-adipate) (PBSA) plastic in soils under ambient and future climates. Here, we show that nitrogen-fixing bacteria facilitate the microbial degradation of PBSA by enhancing fungal abundance, accelerating plastic-degrading enzyme activities, and shaping/interacting with plastic-degrading fungal communities.

Tear osmolarity and tear function assessment in patients with polycystic ovary syndrome / Avaliação da osmolaridade lacrimal e da função lacrimal em pacientes com síndrome dos ovários policísticos

ABSTRACT Purpose: Polycystic ovary syndrome (PCOS) is an endocrine disease characterized by chronic anovulation and hyperandrogenism. Hormonal changes can affect tear function. This study evaluates tear function and impact of hyperandrogenism on it in PCOS patients. Methods: Fifty patients with PCOS and thirty control volunteers were examined for tear break-up time, Schirmer-I and tear osmolarity. Also, serum levels of total testosterone, FSH, LH and AMH were determined in venous blood samples in the early follicular phase. PCOS patients were divided into two groups by plasma total testosterone level: Group A with normal (≤0.513 ng/ml;n=27), Group B with higher hormone level (>0.513 ng/ml;n=23). Healthy control group indicated as Group C (n=30). Results: LH, total testosterone levels were higher in the PCOS group than in the control group (p=0.012; p=0.025). Mean values of tear break-up time and Schirmer-I were different between groups and especially Group A and C were near to each other differing from B (p>0.05). Tear osmolarity results were higher in Group B, compared to A and C (p=0.049; p=0.033). No significant difference detected in tear osmolarity value means of Group A and C (p=0.107). AMH levels were higher in Group B, compared to A and C (p=0.002; p=0.001). AMH levels in Group A were higher than that of C (p=0.002). Positive correlation between levels of total testosterone and AMH was detected in all PCOS patients (n=50;Pearson's r=0.579; p<0.001). Conclusion: Tear function can be affected in PCOS patients with hyperandrogenism. Tear osmolarity is the most sensitive and objective assessment method for ocular surface changes in PCOS.

RESUMO Objetivo: A síndrome do ovário policístico (SOP) é uma doença endócrina caracterizada por anovulação crônica e hiperandrogenismo. As alterações hormonais podem afetar a função cardíaca. Este estudo avalia a função lacrimal e o impacto do hiperandrogenismo sobre ela em pacientes com SOP. Métodos: Cinquenta pacientes com SOP e trinta voluntárias de controle foram examinadas para tempo de ruptura lacrimal, Schirmer-I e osmolaridade lacrimal. Além disso, os níveis séricos de testosterona total, FSH, LH e HAM foram determinados em amostras de sangue venoso na fase folicular precoce.As pacientes com SOP foram divididas em dois grupos por nível de testosterona plasmática total: Grupo A com nível normal (≤0.513 ng/ml; n = 27), Grupo B com nível superior de hormônio (> 0,513 ng/ml; n = 23). Grupo de controle saudável indicado como Grupo C (n = 30). Resultados: Os níveis de LH e testosterona total foram maiores no grupo com SOP do que no grupo controle (p = 0,012; p = 0,025). Os valores médios de tempo de ruptura lacrimal e Schirmer-I foram diferentes entre os grupos, e especialmente os Grupos A e C estavam próximos um do outro, diferente do B (p > 0,05). Os resultados de osmolaridade lacrimal foram maiores no Grupo B, em comparação com A e C (p = 0,049; p = 0,033). Não houve diferença significativa detectada em valor médio de osmolaridade lacrimal nos Grupos A e C (p = 0,107). Os níveis de HAM foram maiores no Grupo B, em comparação com A e C (p = 0,002; p = 0,001). Os níveis de AMH no Grupo A foram superiores aos de C (p = 0,002). Uma correlação positiva entre os níveis de testosterona total e AMH foi detectada em todas as pacientes com SOP (n = 50; Pearson's r = 0,579; p < 0,001). Conclusão: a função lacrimal pode ser afetada em pacientes com SOP com hiperandrogenismo. A osmolaridade lacrimal é o método de avaliação mais sensível e objetivo para alterações da superfície ocular em SOP.