Optimization of Compatible Mixed Cultures for Liquid State Bioconversion of Municipal Wastewater Sludge

The filamentous fungal strains such as Penicillium corylophilum (P), Aspergillus niger (A), Trichoderma harzianum (T) and Phanerochaete chrysosporium (PC) isolated from its relevant sources (wastewater, sewage sludge and sludge cake) were selected for compatible/incompatible mixed cultures. Six combinations of P. corylophilum and A. niger (P/A); P. corylophilum and P. chrysosporium (P/PC); P. corylophilum and T. harzianum (P/T); A. niger and T. harzianum (A/T); A. niger and P. chrysosporium (A/PC); T. harzianum and P. chrysosporium (T/PC) were used to evaluate their potential performance as compatible/incompatible mixed culture for the treatment of municipal wastewater sludge in a bioconversion process. The results of the present study showed that the combinations of P/A, P/PC and A/PC showed compatible growth and the rest of the combinations (P/T, A/T and T/PC) were incompatible cultures. A maximum production of dry biomass and dry filter cake were recorded in the compatible mixed culture of P. corylophilum and A. niger (P/A). A maximum reduction of COD (90%) and a decreased filtration time of treated sludge was observed in the case of P/A microbial mixed culture. The pH value was also affected by the fungal cultures. Effective results were observed by using microbial mixed culture after four days of treatment compared to other treatments (2 and 6 days).     

Varietal differences in the growth of rice plants in response to aluminum and silicon

Effects of Al (0–100 μM) and Si (0–2,000 μM) supplied singly or in combination on root growth of different rice varieties were examined under hydroponic conditions. Al addition inhibited root elongation of rice plants, and the inhibition increased with increasing amount of Al in the culture solution. Among 22 indica varieties and among 8 japonica varieties tested, IAC3 and Nakateshinsenbon were relatively tolerant to AI, respectively, whereas IR45 and Norinl were relatively sensitive to AI, respectively. Si exerted a beneficial effect at all levels of Si treatment on indica varieties, whereas Si supply resulted in a slight increase in the root dry weight of japonica varieties only at the highest level (2,000 μM Silo The alleviation of Al inhibition of rice root growth by Si was observed in the combination of Al and Si treatments. Alleviation was more pronounced for all the Si treatments in indica varieties than in japonica varieties, and the alleviation was maximum with 2,000 μM Si in IR45. The alleviation effect by Si was more pronounced in the AI-sensitive varieties than in the AI-tolerant varieties. The application of Si resulted in an increase in the contents of Al and Si in plants, and there was no relationship between the Al content and Al inhibition in plants.     

Effects of incubation times and moisture regimes on pH values and exchangeable cations in acid sulfate soils as influenced by application rates of basic slag

Severe acidifications in acid sulfate soils (ASSs) have occurred worldwide due to sulfuric acidity, which requires sustainable measures for their reclamation. Accordingly, an incubation study was conducted with the topsoil of two different ASSs (Cheringa and Badarkhali) to evaluate the effects of basic slag (BS; size <1 mm, pH 9.6, Ca 20.8%, Mg 9.8%, etc.), on reduction of acidity and changes in exchangeable cations. It is noted that BS is a byproduct of steel industry in Bangladesh and can be collected almost free of charge. These soils received BS at the rate of 0 (T₀), 11 (T₁), 22 (T₂) and 33 (T₃) t ha⁻¹ under various moisture regimes (saturated condition M₁,_, i.e., 100% moisture content, wetting–drying cycles of 100 and 50% moisture M_2, and moisture at field condition M₃, i.e., 50%). The impacts of these treatments on some selected parameters in these soils were studied within 180 days of incubation. The application of BS was found to increase the pH of soils from 3.6 to 5.1 for Cheringa, 3.9 to 5.2 for Badarkhali soils at the end of incubation. These increments were more striking with the highest doses of BS under saturated moisture conditions in both of the soils. The ECe of the soils was not much influenced by the application of BS regardless of time. The treatments exerted significant (P ≤ 0.05) effects on exchangeable cations in different periods of incubation. The striking changes were recorded for the rate of increments of Ca²⁺ and Mg²⁺, which were about 2–3 times higher for Ca and more than 2 times higher for Mg²⁺ compared with the control after 180 days of incubation. These results suggest that the application of BS not only increased the Ca²⁺ to the higher amount than that of the increment of Mg²⁺ in the soils, but also improved one of the important criteria of Ca²⁺ and Mg²⁺ ratio in the soils.     

Feasibility of a single-species quota system for management of the Malaysian multispecies purse-seine fishery

Malaysian fisheries employ multiple measures to improve management; however, not all are well-suited to the multispecies fisheries. As part of a pilot project, an individual quota system was introduced for the purse-seine fishery off the East Coast of Peninsular Malaysia (ECPM), but no assessment of this particular measure nor the feasibly of its implementation has been confirmed. Therefore, this study analysed spatial and temporal patterns of purse-seine fishing, by collecting catch composition data per landing and its fishing ground within three period fishery surveys between August 2017 and September 2018 at six different landing sites. Similarity and cluster analysis examined species composition and diversity to determine the feasibility of implementing a single-species quota system in this multispecies fishery. Some overlapped of indices results and minor difference in catch composition were found due to changes in spatial and temporal fishing activities. However, no specific spatial or temporal patterns were discernible as structuring the fishing grounds used by purse-seiners. The absence of patterns, using the available data, might be attributable to huge species aggregations and widely distributed and homogenously mixed fish stocks. Thus, it is likely impractical to manage species individually in such a multispecies fishery.     

Salinity stress response in estuarine fishes from the Murray Estuary and Coorong,South Australia

Estuaries are unstable ecosystems and can be changed by the environmental and anthropogenic impact. The Murray Estuary and Coorong were degraded by drought and low freshwater input in the last decade and therefore transformed into the largest hyper-saline lagoon in Australia. This study evaluates the physiological stress of two estuarine fish species (small-mouthed hardyhead Atherinosoma microstoma and Tamar goby Afurcagobius tamarensis) to the induced salinity change in captivity. The test fishes were collected from the Coorong and transported to the laboratory in the water from the Coorong. Each fish species was exposed to different levels of salinity, and a number of enzymes were assessed to measure the stress response of fish to salinity change. The activity of reactive oxygen species was significantly increased with the salinity change in both fish species compared with the fish in the control. Significant salinity effect on superoxide dismutase activity was observed on Tamar goby but not on small-mouthed hardyhead. Conversely, the impact of salinity on catalase activity was detected on small-mouthed hardyhead but not on Tamar goby. The study reveals that the induction of physical stress by salinity changes occurred in both Tamar goby and small-mouthed hardyhead despite the varying response of antioxidant enzymes between fish species. The study provides an insight into the understanding of physiological adaptation in estuarine fish to salinity change. The results could improve our knowledge on stress response and resilience of estuarine fish to hypo- and hyper-salinity stress.     

Fine mapping of quantitative trait loci affecting organ weights by mouse intersubspecific subcongenic strain analysis

The genetic architecture of organ weights is not well understood. In this study, we fine‐mapped quantitative trait loci (QTLs) affecting organ weights by characterizing six intersubspecific subcongenic mouse strains with overlapping and non‐overlapping genomic regions on chromosome 2 derived from wild Mus musculus castaneus. QTLs for heart, lung, spleen and kidney weights were revealed on a 6.38‐Mb genomic region between two microsatellite markers, D2Mit323 and D2Mit472. Effects of the castaneus alleles at the organ weight QTLs were all opposite in direction to a body weight QTL previously mapped to the same genomic region. In addition, new QTLs for lung and kidney weights were revealed on a different 3.57‐Mb region between D2Mit205 and D2Mit182. Their effects were dependent on that of another body weight QTL previously mapped to that genomic region. The organ weight QTLs revealed were all duplicated in independent analyses with F₂ intercross populations between subcongenic strains carrying these QTLs and their background strain. The findings suggested that organ weights are not exclusively regulated by genetic loci that commonly influence overall body weight and rather that there are loci contributing to the growth of specific organs only.     

Hydathode morphology and role of guttation in excreting sodium at different concentrations of sodium chloride in eddo

Mature leaves of field-grown eddo plants were used for observing hydathode morphology by light and scanning electron microscopies. There were approximately five hydathode pores on the adaxial surface of each leaf tip. A ring structure with two borders around the pore was detected in this study. Further observations revealed a large cavity underneath the pores. The cavity was directly connected to vascular bundles that lacked a bundle sheath, via intercellular spaces among loosely organized parenchyma cells. Many crystal cells were present around the cavity and vascular bundles. To evaluate the role of guttation in sodium excretion under salinity stress, eddo plants were grown in hydroponic solutions containing 0, 1, 4, 8, and 12 mM sodium chloride (NaCl) for 7 d. As the NaCl concentration in the hydroponic solution increased, the sodium contents increased in leaf blades, petioles, and roots but remained unchanged in corms. The sodium concentration in the guttation fluid increased; however, the volume of guttation fluid decreased with increasing NaCl concentrations. Therefore, sodium elimination via guttation decreased with increasing NaCl concentrations. The ratios of the sodium content in guttation fluid to that of leaf blades, leaves, and whole plants decreased with increasing NaCl concentrations. The ratios of potassium to sodium contents in leaves, roots, and guttation fluid also decreased as the NaCl concentration increased. These results indicate that guttation did not eliminate sufficient sodium to play a role in adjusting sodium homeostasis and the ratios of potassium to sodium contents in eddo plants under saline conditions.