Study of Calcium Ion Diffusion in Components of Maize Kernels During Traditional Nixtamalization Process

Our report shows the calcium ion diffusion process through the different parts of maize kernels (pericarp, endosperm, and germ) during the traditional nixtamalization process as a function of steeping time (t) 0–24 hr. The cooking step of the nixtamalization process used 3 kg of maize kernels in 6L of water and 2% calcium hydroxide (w/w). The cooking temperature was 92°C for 40 min. The calcium content of the samples was measured using atomic absorption spectroscopy. We found that the whole instant corn flour, pericarp, endosperm, and germ, had a nonlinear relationship to steeping time, showing a local maximum at 9 hr. Analysis of the different parts of the nixtamalized kernels showed that in short steeping times (0–5 hr) calcium diffusion took place mainly in the pericarp. Calcium diffusion in the endosperm and germ occurred gradually over longer steeping times. However, the physical state of the kernels (broken kernels) accelerated the diffusion process. Calcium diffusion occurred first in the pericarp, followed by the endosperm and germ. Immediately after cooking (t = 0 hr), we found a 1.148% calcium content in the pericarp, 0.007% in the germ, and 0.028% in the endosperm. After 24 hr of steeping, the calcium contents were 2.714% in the pericarp, 0.776% in the germ, and 0.181% in the endosperm. In another study, the calcium content in the endosperm was measured by first separating the 10% from the outermost, followed by another 10% from the next endosperm tissue, and concluding with the remaining 80%. Calcium ions were present mainly in the outermost layers of the endosperm. The damaged kernels steeped for more than 5 hr showed greater calcium concentrations than the undamaged counterparts.     

Effects of ocean climate on the length and condition of forage fish in the Gulf of Alaska

Climatic drivers of the size and body condition of forage fish in the North Pacific are poorly known. We hypothesized that length and condition of forage fish in the Gulf of Alaska (GoA) vary in relation to ocean temperature on multiple scales. To test this hypothesis, we analyzed morphometric data for capelin (Mallotus catervarius) and Pacific sand lance (PSL; Ammodytes personatus) sampled by a seabird (Cerorhinca monocerata) in two regions of the GoA, 1993–2016. Based on previous studies, we predicted that capelin length and body condition (Fulton's K) would be negatively related to the Pacific Decadal Oscillation (PDO) and sea surface temperature (SST), whereas PSL length and condition would be positively related. Interannual variation in length and body condition was evaluated relative to seasonal values of ocean climate using regression. Forage fish length and condition varied interannually, between sampling regions, and were dependent on the size/age class of the fish sampled. As predicted, length and body condition of capelin (mostly age 1+) were negatively related to the PDO and SST. Relationships with ocean climate for PSL varied by size/age class: positive for putative age‐0 fish and negative for putative age‐1+ fish. We conclude that our hypothesis was supported for capelin and partially supported for PSL. This study demonstrates that ocean climate determines key morphometric characteristics of forage fish that may relate to interannual variation in the energetic value of prey, and provides an example of how seabirds can be used to obtain specimens for evaluations of potential prey quality.     

Biofouling development in marine fish farm influenced by net colour,immersion period and environmental conditions

Biofouling poses low productivity and high maintenance in aquaculture. This study simulated the nets of fish cages to investigate biofouling composition and development as influenced by net colour, immersion period and environmental conditions. Yellow and green net panels were immersed for 60 days and sampled at 7, 15, 30, 45 and 60 days. Results revealed that biofouling composition was dominated by Bryozoan Bugula sp. (31%–38% cover), tanaids Tanaidae (64–146 individuals.100 cm^‐2) and nematodes Linhomoeidae and Oncholaimidae (142–189 individuals.100 cm^‐2). Biofouling development was observed in succession patterns of harpacticoid–nematode–amphipod–tanaid in yellow nets and amphipod–nematode in green nets. Water velocity within the cages significantly and positively influenced the total cover, biomass and the densities of amphipods, bivalves, polychaetes, fish eggs and bryozoans. Polychaetes, gastropods, fish eggs and macroalgae were present in green nets and absent in yellow nets at 7 days. Uniformity of biofouling assemblage in both net colours was observed beyond 7 days which may be largely explained by brown biofilm formation. The result of the study revealed the dynamics of biofouling in a marine fish farm and provides vital information for developing strategies in biofouling management to lessen its impacts.     

Growth,survival, body composition and amino acid profile of Macrobrachium borellii against the limitation of feeds with different C:N ratios with comments about application in integrated multi‐trophic aquaculture

One way to attain more sustainable aquaculture systems is through the species diversification and optimization of the feed input, such as obtained by integrated multi‐trophic aquaculture (IMTA). Macrobrachium borellii is a native freshwater prawn that reunites many useful features to be implemented in an IMTA. The aim of this study was to gather information about to which extent M. borellii can survive, grow and maintain body composition against feed limitation. The C:N ratios of feedstuffs were variable in order to simulate a hypothetical scenario of an integrated culture with fish of different trophic habits. The nutritional aspects (amino acid profile and proximal composition) of feeds and prawns were also analysed. Macrobrachium borellii could grow, survive and maintain the proximal content and C:N ratio of its muscle tissue with all feedstuffs but exhibited higher biomass gain and specific growth rate consuming feeds with lower C:N ratios. In this view, the integration of this prawn with omnivore or carnivore fish species should be recommended. The amino acid profile exhibited little variation before and after the experimental period, and was rich in lysine, leucine and arginine. In this study, it was also discussed the nutritional aspects of M. borelliii as a valuable by‐product to human and animal nutrition.     

A Field Test of Root Zone Water Quality Model—Pesticide and Bromide Behavior

The Root Zone Water Quality Model (RZWQM) is a process-based model developed recently by USDA–ARS scientists. The model integrates physical, chemical and biological processes to simulate the fate and movement of water and agrochemicals over and through the root zone at a representative point in a field with various management practices. The model was evaluated using field data for the movement of water and bromide, and the transformation and transport of cyanazine and metribuzin in the soil profile. The model reasonably simulated soil water and bromide movement. Pesticide persistence was predicted reasonably well using a two-site sorption model that assumes a rate-limited (i.e. long-term) adsorption–desorption process with the additional assumption of negligible degradation of inter-aggregate adsorbed pesticides.     

Regeneration of protoplasts from hyphal strands ofVolvariella volvacea

A series of experiments on the preparation and regeneration of protoplasts from hyphal strands ofVolvariella volvacea (Bull. ex. Fr.) Singer were conducted with the aim of optimizing the conditions for its efficient regeneration. One commercial (Vvcl) and two wild (EAAC-0001 and EAAC-0002) strains ofV. volvacea from the Philippines were used and subjected to varying conditions to determine the most efficient means for regeneration of their protoplasts. The effects of age and type of strain, pH, type and concentration of osmotic stabilizer, enzymatic composition, treatment time, temperature, reciprocal frequency during enzymatic lysis of the cell wall, and centrifugation conditions were investigated. Results showed that the three strains ofV. volvacea had varying responses in terms of yield, size, and ability of their protoplasts to regenerate into the protoplast regeneration medium. Among the three strains, EAAC-0002 had the highest rate of regeneration. The 5-day-old culture ofV. volvacea, when subjected to a combination of 2% Novozyme 234 and 0.2% chitinase in 0.6M mannitol (pH 6.0) for 3 h at 30°C, 90 strokes/min and centrifuged at 1100 g for 10 min; produced an efficient yield of protoplasts with a relatively high regeneration rate.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, Japan, April 2–5, 1997     

New Ikarugamycin Derivatives with Antifungal and Antibacterial Properties from Streptomyces zhaozhouensis

A bioassay guided fractionation of the ethyl acetate extract from culture broths of the strain Streptomyces zhaozhouensis CA-185989 led to the isolation of three new polycyclic tetramic acid macrolactams (1–3) and four known compounds. All the new compounds were structurally related to the known Streptomyces metabolite ikarugamycin (4). Their structural elucidation was accomplished using a combination of electrospray-time of flight mass spectrometry (ESI-TOF MS) and 1D and 2D NMR analyses. Compounds 1–3 showed antifungal activity against Aspergillus fumigatus, Candida albicans and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).     

Pro‐inflammatory caspase‐1 activation during the immune response in cells from rainbow trout Oncorhynchus mykiss (Walbaum 1792) challenged with pathogen‐associated molecular patterns

In response to pathogens, the higher vertebrate innate immune system activates pro‐inflammatory caspase‐1 which is responsible for the processing and secretion of several important cytokines involved in the host's defence against infection. To date, caspase‐1 has been described in few teleost fish, and its activity has been demonstrated through substrate cleavage and inhibition by pharmacological agents. In this study, the detection of the active form of caspase‐1 during the immune response in salmonid fish is described, where two antibodies were produced. These antibodies differentially recognize the structural epitopes of the inactive pro‐caspase‐1 and the processed active form of the caspase. Firstly, caspase‐1 activation was demonstrated in vitro by ELISA, Western blotting and immunocytochemistry in rainbow trout macrophages exposed to different pathogen‐associated molecular patterns plus the pathogen Aeromonas hydrophila. This activity was clearly abrogated by a caspase inhibitor and seems to be unrelated to IL‐1β secretion. Caspase‐1 activation was then validated in vivo in gill cells from fish challenged with Aeromonas salmonicida. These results represent the first demonstration of caspase‐1 activation in salmonids, and the first evidence of the putative regulatory role which this protease plays in inflammatory response in this fish group, as described for some other teleosts and mammals.