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Characterization and Genomic Analyses of dsDNA Vibriophage vB_VpaM_XM1, Representing a New Viral Family
No full textA novel vibriophage vB_VpaM_XM1 (XM1) was described in the present study. Morphological
analysis revealed that phage XM1 had Myovirus morphology, with an oblate icosahedral head and
a long contractile tail. The genome size of XM1 is 46,056 bp, with a G + C content of 42.51%, encoding
69 open reading frames (ORFs). Moreover, XM1 showed a narrow host range, only lysing Vibrio
xuii LMG 21346 (T) JL2919, Vibrio parahaemolyticus 1.1997, and V. parahaemolyticus MCCC 1H00029
among the tested bacteria. One-step growth curves showed that XM1 has a 20-min latent period and
a burst size of 398 plaque-forming units (PFU)/cell. In addition, XM1 exhibited broad pH, thermal,
and salinity stability, as well as strong lytic activity, even at a multiplicity of infection (MOI) of 0.001.
Multiple genome comparisons and phylogenetic analyses showed that phage XM1 is grouped in
a clade with three other phages, including Vibrio phages Rostov 7, X29, and phi 2, and is distinct
from all known viral families that have ratified by the standard genomic analysis of the International
Committee on Taxonomy of Viruses (ICTV). Therefore, the above four phages might represent a new
viral family, tentatively named Weiviridae. The broad physiological adaptability of phage XM1 and its
high lytic activity and host specificity indicated that this novel phage is a good candidate for being
used as a therapeutic bioagent against infections caused by certain V. parahaemolyticus strain
SIASATAN KO-PYROLISIS SISA IKAN DAN TANDAN BUAH KOSONG: ANGGARAN PARAMETER KINETIK DAN TERMODINAMIK, HASIL PRODUK DAN PENCIRIAN BIOCHAR
No full textThis study explores the feasibility of utilising fish waste (FW) and empty fruit
bunches (EFB) as feedstocks in co-pyrolysis. The research aims to optimize copyrolysis
by estimating kinetic and thermodynamic parameters, evaluating product
yields at various temperatures, and characterising biochar properties.
Thermogravimetric analysis was employed at heating rates of 10, 20, and 30 ?C/min,
while kinetic and thermodynamic parameters were estimated using the Kissinger-
Akahira-Sunose and Flynn-Wall-Ozawa methods. Reaction mechanisms were inferred
using Criado plots. Product yields were measured in a tube furnace at 500 - 600 ?C
temperatures. The biochar was characterised using Fourier-transform infrared
spectroscopy and scanning electron microscopy. Results revealed that activation
energies (?!) ranged from 25.56 to 170.76 kJ/mol, with 75FW:25EFB exhibiting the
lowest ?!. The complexity of co-pyrolysis reactions was evidenced by frequency
factors with average values spanning from 1.65 x 108 to 5.66 x 1011 s-1. Reaction
models identified included Power law, Avrami-Erofeev, Reaction-order, Geometrical
contraction, and Diffusion models. The changes in enthalpy and entropy analyses
highlighted the energy-intensive and thermodynamic equilibrium tendencies of the
process, with the change in Gibbs free energy confirming the feasibility of copyrolysis.
FW-rich mixtures produced higher biochar yields, attributed to their ash
content, while EFB-rich mixtures favored biogas production due to higher volatile content. At 500 ?C, 75FW:25EFB achieved 47 % biochar yield, which decreased to 42
% at 600 ?C. EFB demonstrated superior gas production potential, reaching 67 %
biogas yield at 600 ?C. Co-pyrolysis resulted in improved liquid fuel and gas yields
compared to individual feedstocks. Biochar analysis revealed that FW-rich biochar
contained nitrogenous and aromatic functional groups, while lignocellulosic structures
characterized EFB-rich biochar. Co-pyrolyzed biochar also showed enhanced
carbonization, porosity, and functionality, making it ideal for soil amendment, water
filtration, and renewable energy uses. The study highlights the advantages of
optimizing FW and EFB ratios, with 75FW:25EFB and 50FW:50EFB emerging as the
most effective blends for balanced product yields and biochar quality. This research
demonstrates the potential of FW and EFB co-pyrolysis as a sustainable approach to
optimize biochar production and convert waste into valuable resources
Blueprint for Blue Carbon: Lessons from Seychelles for Small Island States
No full textBlue carbon has been proposed as a nature-based solution for climate change mitigation;
however, a limited number of published works and data and knowledge gaps hinder the development
of small island developing states? (SIDS) national blue carbon resources globally. This paper reviews
the blue carbon ecosystems of Seychelles as a case study in the context of SIDS, comparing estimations
by the Blue Carbon Lab and recent blue carbon (mangrove and seagrass) evaluations submitted to
the Seychelles national government. Mangroves (2195 ha, 80% in Aldabra Atoll) and seagrasses
(142,065 ha) dominate in Seychelles, with coral reefs having the potential for carbon sequestration
(169,000 ha). Seychelles is on track to protecting its blue carbon, but these systems are threatened
by rising sea levels, coastal squeeze, erosion, severe storms, and human activities. The importance
of carbon inventories, accounting institutions, and continuous monitoring of blue carbon systems
is discussed. Blue accounting is necessary for accurate accounting of carbon sequestration and
carbon storage, generating carbon credits, and representing impactful reductions in greenhouse
gases for NDCs. Challenges and opportunities include policy legislation regarding ownership
rights, accreditation and certification for carbon credits, sustainable financing mechanisms like
natural asset companies and blue tokens, local engagement for long-term success, and carbon
market dynamics following COP27. The restoration and regulation of blue carbon resources for
optimal ecosystem services delivery, carbon inventories, and blue carbon policy are recommended
development priorities. Blue carbon ecosystems have the potential to contribute to NDCs of SIDS
while simultaneously offering sustainable development pathways for local communities through the
multiple ecosystem services they provide
Morphological, Toxicological, and Biochemical Characterization of Two Species of Gambierdiscus from Bah?a de La Paz, Gulf of California
No full textWe describe five new isolates of two Gambierdiscus species from Bah?a de La Paz in the
southern Gulf of California. Batch cultures of Gambierdiscus were established for morphological
characterization using light microscopy (LM) and scanning electron microscopy (SEM). Pigment
and amino acid profiles were also analyzed using high-performance liquid chromatography (HPLCUV
and HPLC-DAD). Finally, toxicity (CTX-like and MTX-like activity) was evaluated using the
Artemia salina assay (ARTOX), mouse assay (MBA), marine fish assay (MFA), and fluorescent receptor
binding assay (fRBA). These strains were identified as Gambierdiscus cf. caribaeus and Gambierdiscus cf.
carpenteri. Toxicity for CTX-like and MTX-like activity was confirmed in all evaluated clones. Seven
pigments were detected, with chlorophyll a, pyridine, Chl2, and diadinoxanthin being particularly
noteworthy. For the first time, a screening of the amino acid profile of Gambierdiscus from the Pacific
Ocean was conducted, which showed 14 amino acids for all strains except histidine, which was only
present in G. cf. caribeaus. We report the presence of Gambierdiscus and Fukuyoa species in the Mexican
Pacific, where ciguatera fish poisoning (CFP) cases have occurred
Essential and Non-Essential Elemental Composition and Health Risks in Pacifi Sardine in the Northwest Pacifi Ocean
No full textPacific sardine (Sardinops sagax) in the northwest Pacific Ocean (NPO) not only preserve the equilibrium of the NPO food chain, but also serve as a source of nutrition for humans. In order to evaluate the levels of various elements in S. sagax, we collected specimens from NWP waters and ascertained the quantities of four macronutrients, nine essential trace elements, and twelve
non-essential trace elements. The factors (fatness, sex, sexual maturity, body length, body weight, and age) influencin the concentration were investigated, and the correlations of trace elements were examined. Additionally, the Estimated Daily Intake (EDI) approach and the Target Hazard Quotient (THQ) methodology were used to assess contamination levels and associated consumption risks. The
results revealed that the macronutrient content (54?10,500 mg kg?1) was higher than the necessary trace elements (0?488 mg kg?1) and the non-essential trace elements (0?448 mg kg?1), and most of
the elements showed positive correlation with each other. Almost all of the element concentrations were below the maximum permitted levels (MPLs) recommended by the FAO/WHO, except for As and Cd. The factors, including fatness, sexual maturity, body length, body weight, and age, showed a negative correlation with most of the trace elements. The outcomes of the stepwise regression analysis showed that sex and stage of sexual maturation were the principal biological factors influencing elemental content. The risk assessment and standard dietary intake levels indicated that the potential health issues associated with the consumption of S. sagax were negligible
Direct Preparation of Alginate Oligosaccharides from Brown Algae by an Algae-Decomposing Alginate Lyase AlyP18 from the Marine Bacterium Pseudoalteromonas agarivorans A3
No full textAlginate oligosaccharides (AOs), derived from alginate degradation, exhibit diverse biological activities and hold significant promise in various fields. The enzymatic preparation of AOs relies on alginate lyases, which offers distinct advantages. In contrast to the conventional use of sodium alginate derived from brown algae as the substrate for the enzymatic preparation of AOs, AO preparation directly from brown algae is more appealing due to its time and energy efficiency. Thus, the identification of potent alginate lyases and cost-effective brown algae substrates is crucial for optimizing AO production. Herein, we identified and characterized an alginate lyase, AlyP18, capable of efficiently decomposing algae, from a marine bacterium Pseudoalteromonas agarivorans A3 based on secretome analysis. AlyP18 is a mesothermal, endo-type and bifunctional alginate lyase with high enzymatic activity. Two brown algae substrates, Laminaria japonica roots and Macrocystis pyrifera, were used for the AO preparation by AlyP18. Upon optimization of AlyP18 hydrolysis parameters, the substrate degradation efficiency and AO production reached 53% and ~32% for L. japonica roots, respectively, and 77% and ~46.5% for M. pyrifera. The generated AOs primarily consisted of dimers to pentamers, with trimers and tetramers being dominant. This study provides an efficient alginate lyase and alternative brown algal feedstock for the bioconversion of high-value AOs from brown algae
In Vitro Culture of Glochidia and Morphological Changes in Juveniles of the Endangered Freshwater Mussel Solenaia oleivora
No full textThe artificial propagation of the endangered Solenaia oleivora, with unknown fish hosts, was
performed via in vitro culture with bighead carp, grass carp, common carp, bovine, and rabbit sera.
The effects of glochidium density on transformation rates were evaluated, and the development of
juveniles that metamorphosed successfully was documented. The control group had a transformation
rate of 0 and a contamination rate of 0. No significant differences were found in the transformation
and contamination rates of the bighead carp, grass carp, and common carp serum groups, and
their transformation rates were significantly higher, and contamination rates were significantly
lower than those of the bovine and rabbit serum groups. Moreover, no significant differences were
observed in the transformation rates of glochidia (culture density, 2000?5000 glochidia/dish) in
contamination-free conditions. Specimen shell length/height increased from 1.08 ? 0.01 on the first
day to 3.08 ? 0.29 during the 13th week. On the basis of anterior and posterior growth differences,
juvenile growth was divided into the following three phases: the rapid anterior growth period,
distinct anterior and posterior idiophase, and rapid posterior growth period. This study not only
provides technological support for the artificial propagation of S. oleivora but also lays a foundation
for resource recovery
An Early-Stage Structural Design of a Semi-Submersible Platform for Floating Offshore Wind Turbines in Chilean Waters
No full textTo advance offshore wind energy technologies in South America, this study addresses
the early-stage design challenges of a floating support structure for a 5 MW wind turbine. The aim
is to develop a robust and efficient floating structure capable of withstanding the diverse forces
imposed by the Valdivian environment. Utilizing SolidWorks, a 3D model based on a comprehensive
review of semi-submersible structures with three columns is proposed. The structural model is
subjected to a rigorous evaluation using the finite element method, with which linear static and
buckling analyses are performed in compliance with the Det Norske Veritas (DNV) classification
society. The proposed tri-floater platform design shows a 30% weight reduction when compared with
other proposed models. The finite element analysis includes an extreme condition of 13 m waves
that suggests the adequate performance of the proposed platform in Chilean waters, and offers a
conceptual preliminary step for floating support structure designs in Chile
Development of Biological Risk Assessment Protocols for Evaluating the Risks of In-Water Cleaning of Hull-Fouling Organisms
No full textHerein, we evaluate the scientific basis for managing hull fouling of ships entering Korean ports, diagnose biological risks that may occur when in-water cleaning (IWC) systems remove hull fouling, and present a protocol for evaluating these risks (the Korean Infection Modes and Effects Analysis; K-IMEA). Protocol development included the selection of core elements and scenario design for IWC and the evaluation of regrowth experiments. The K-IMEA index was designed by considering the inoculation pathway of attaching organisms in all processes to ships that enter a port for in-water
cleaning. A number of risk indices were defined: R1?Introduction/Establishment of alien species before in-water cleaning; R2?Establishment of alien species escaped during in-water cleaning; R3?Introduction/Establishment of alien species after in-water cleaning; and R4?Establishment of alien species in effluent water. K-IMEA regrowth experiments (R2 and R4) using the in-water cleaning effluent showed that the attachment and regrowth of prokaryotes, microalgae, and macroalgae were
successfully detected. In particular, prokaryotes were observed in samples filtered through a 5 ?m
mesh of the in-water cleaning effluent, even at a low fouling rating (Levels 1?2). These experiments
suggest a necessity to consider a secondary treatment method in addition to the primary filtration method for the treatment of in-water cleaning effluents
Effects of estuary reopening management on the fish community in the Nakdong River Estuary
No full textEstuary reopening is a means of restoring estuarine habitats, which has recently
been implemented in a few developed countries. The regeneration of a brackish
zone in the Nakdong River Estuary (NRE), South Korea,were tested through a series
of barrage reopening. During the same period, we conducted extensive fish
surveys in the upper part of the NRE barrage on a monthly basis from 2017 to
2021, and subsequently determined whether fish populations and communities
were affected by the reopening. The results showed that the reopening of the NRE
hardly affected the fish community structure, as non-native species such as
Erythroculter erythropterus and Lepomis macrochirus maintained their
dominance. Still, we discovered that certain euryhaline species are positively
affected by estuary reopening, as total 46 Japanese eels (Anguilla japonica) were
captured after the reopening, which had not been detected before the reopening.
By comparing the size structure of various fish species, we discovered that size
distribution of native and migratory species presented more positively skewed
pattern after the reopening, while size structure in non-native species remained
relatively unchanged normally distributed pattern. Piecewise structural equation
modelling revealed that the NRE had become more complex ecosystem, as
migratory fish species abundance and biomass started to show a positive
correlation with hydraulic factors such as discharge and negative correlation
with seasonality after the reopening. We concluded that estuary reopening
created some changes in migratory and native freshwater species but such
changes were not notably detected in non-native species. Therefore,
appropriate sluice operation methodologies, such as considering the migration
seasons of migratory species, should be developed. Additionally, human-involved
management policies are required to regulate non-native species populations