Evaluating lignin degradation under limited oxygen conditions by bacterial isolates from forest soil.

Lignin, a heterogeneous aromatic polymer present in plant biomass, is intertwined with cellulose and hemicellulose fibrils, posing challenges to its effective utilization due to its phenolic nature and recalcitrance to degradation. In this study, three lignin utilizing bacteria, Klebsiella sp. LEA1, Pseudomonas sp. LEA2, and Burkholderia sp. LEA3, were isolated from deciduous forest soil samples in Nan province, Thailand. These isolates were capable of growing on alkali lignin and various lignin-associated monomers at 40 °C under microaerobic conditions. The presence of Cu2+ significantly enhanced guaiacol oxidation in Klebsiella sp. LEA1 and Pseudomonas sp. LEA2. Lignin-related monomers and intermediates such as 2,6-dimethoxyphenol, 4-vinyl guaiacol, 4-hydroxybenzoic acid, benzoic acid, catechol, and succinic acid were detected mostly during the late stage of incubation of Klebsiella sp. LEA1 and Pseudomonas sp. LEA2 in lignin minimal salt media via GC-MS analysis. The intermediates identified from Klebsiella sp. LEA1 degradation suggested that conversion and utilization occurred through the ß-ketoadipate (ortho-cleavage) pathway under limited oxygen conditions. The ability of these bacteria to thrive on alkaline lignin and produce various lignin-related intermediates under limited oxygen conditions suggests their potential utility in oxygen-limited processes and the production of renewable chemicals from plant biomass.

Time-Restricted Inquiry-Based Learning Promotes Active Student Engagement in Undergraduate Zoology Laboratory.

Organizing a zoology laboratory for an undergraduate course is often a challenge, particularly in a limited-resource setting, due to the vast variety of topics to cover and the limited numbers of preserved specimens and permanent slides. In zoology, the class structure generally takes the form of a lecture demonstration followed by sample exhibition stations. This setting often fails to actively engage the majority of students in exploring the specimens. Here we propose an alternative organization of a zoology class lab format comprised of short guided-inquiry, time-restricted lab stations, and a freely structured follow-up project intended to increase attention and conceptual understanding of the lab topic. The lab is designed in two parts: a 10-minute in-class rotation portion, where small groups of students take turns investigating specimens following an instructor demonstration, and an after-class group assignment. We implemented the strategy for two years, and it is clear that our approach significantly increased students' active engagement in the class. The time-restricted scheme ensures all students participate despite limited resources, while the guided instructions keep the students focused on the topic. Furthermore, the team assignment portion, in particular the media creation aspect, promoted teamwork among group members.

Point-of-care rapid detection of Vibrio parahaemolyticus in seafood using loop-mediated isothermal amplification and graphene-based screen-printed electrochemical sensor.

Vibrio parahaemolyticus is one of the most important foodborne pathogens that cause various life-threatening diseases in human and animals. Here, we present a rapid detection platform for V. parahaemolyticus by combining loop-mediated isothermal amplification (LAMP) and disposable electrochemical sensors based on screen-printed graphene electrodes (SPGEs). The LAMP reactions using primers targeting V. parahaemolyticus toxR gene were optimized at an isothermal temperature of 65 °C, providing specific detection of V. parahaemolyticus within 45 min at the detection limit of 0.3 CFU per 25 g of raw seafood. The LAMP amplicons can be effectively detected using unmodified SPGEs, redox active molecules namely Hoechst-33258 and a portable potentiostat. Therefore, the proposed system is particularly suitable as a point-of-care device for on-site detection of foodborne pathogens.

Alterations of organ histopathology and metallothionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure.

Common silver barb, Puntius gonionotus, exposed to the nominal concentration of 0.06 mg/L Cd for 60 d, were assessed for histopathological alterations (gills, liver and kidney), metal accumulation, and metallothionein (MT) mRNA expression. Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae, vacuolization in hepatocytes, and prominent tubular and glomerular damage in the kidney. In addition, kidney accumulated the highest content of cadmium, more than gills and liver. Expression of MT mRNA was increased in both liver and kidney of treated fish. Hepatic MT levels remained high after fish were removed to Cd-free water. In contrast, MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water. The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.