Sampling, separation, and quantification of N-acyl homoserine lactones from marine intertidal sediments

N-acyl homoserine lactones (AHLs) are molecules produced by many Gram-negative bacteria as mediators of cell-cell signaling in a mechanism known as quorum sensing (QS). QS is widespread in marine bacteria regulating diverse processes, such as virulence or excretion of polymers that mediate biofilm formation. Associated eukaryotes, such as microalgae, respond to these cues as well, leading to an intricate signaling network. To date, only very few studies attempted to measure AHL concentrations in phototrophic microbial communities, which are hot spots for bacteria-bacteria as well as microalgae-bacteria interactions. AHL quantification in environmental samples is challenging and requires a robust and reproducible sampling strategy. However, knowing about AHL concentrations opens up multiple perspectives from answering fundamental ecological questions to deriving guidelines for manipulation and control of biofilms. Here, we present a method for sampling and AHL identification and quantification from marine intertidal sediments. The use of contact cores for sediment sampling ensures reproducible sample surface area and volume at each location. Flash-freezing of the samples with liquid nitrogen prevents enzymatic AHL degradation between sampling and extraction. After solvent extraction, samples were analyzed with an ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) method that allows to baseline-separate 16 different AHLs in less than 10 min. The sensitivity of the method is sufficient for detection and quantification of AHLs in environmental samples of less than 16 cm(3)

Bioreactor for microalgal cultivation systems: strategy and development

Microalgae are important natural resources that can provide food, medicine, energy and various bioproducts for nutraceutical, cosmeceutical and aquaculture industries. Their production rates are superior compared to those of terrestrial crops. However, microalgae biomass production on a large scale is still a challenging problem in terms of economic and ecological viability. Microalgal cultivation system should be designed to maximize production with the least cost. Energy efficient approaches of using light, dynamic mixing to maximize use of carbon dioxide (CO2) and nutrients and selection of highly productive species are the main considerations in designing an efficient photobioreactor. In general, optimized culture conditions and biological responses are the two overarching attributes to be considered for photobioreactor design strategies. Thus, fundamental aspects of microalgae growth, such as availability of suitable light, CO2 and nutrients to each growing cell, suitable environmental parameters (including temperature and pH) and efficient removal of oxygen which otherwise would negatively impact the algal growth, should be integrated into the photobioreactor design and function. Innovations should be strategized to fully exploit the wastewaters, flue-gas, waves or solar energy to drive large outdoor microalgae cultivation systems. Cultured species should be carefully selected to match the most suitable growth parameters in different reactor systems. Factors that would decrease production such as photoinhibition, self-shading and phosphate flocculation should be nullified using appropriate technical approaches such as flashing light innovation, selective light spectrum, light-CO2 synergy and mixing dynamics. Use of predictive mathematical modelling and adoption of new technologies in novel photobioreactor design will not only increase the photosynthetic and growth rates but will also enhance the quality of microalgae composition. Optimizing the use of natural resources and industrial wastes that would otherwise harm the environment should be given emphasis in strategizing the photobioreactor mass production. To date, more research and innovation are needed since scalability and economics of microalgae cultivation using photobioreactors remain the challenges to be overcome for large-scale microalgae production

Cost analysis of treating incomplete miscarriage with dilatation and curettage in Universiti Kebangsaan Malaysia Medical Centre in 2010

Background : Miscarriage is a common problem in pregnancy which can occur during early, mid or late pregnancy. Incomplete miscarriage can be treated expectantly, medically or surgically. The most preferred method used in UKMMC is using sharp curettage. Methodology : This study is conducted in the UKMMC from 1st January 2010 to 30th March 2010. The purpose of this study is to analyze the cost of treating incomplete miscarriage using metal sharp curettage from the provider’s perspective per patient-day. Result : A total of 17 samples were eligible for analysis from 46 patients who fulfilled the inclusion and exclusion criteria. The cost is derived from cost calculation on capital and recurrent costs. Results showed that the average cost for treating incomplete miscarriage using sharp curettage per day is RM252.56. Recurrent costs contributed 83.3% of the total treatment with overhead cost was the biggest percentage (51.6%). Discussion The treatment cost for incomplete miscarriage using sharp curettage is found to be higher as compared to medical approach according to literatures. The higher cost of surgical approach was mainly attributed to the recurrent cost which is included in the calculation. Conclusion : Effective usage of the operation theatre and all resources should be managed and utilized well in order to achieve optimum outcome

Methodologies and standards for monitoring antimicrobial use and antimicrobial resistance in shrimp aquaculture

Antimicrobials are commonly used to treat and prevent bacterial diseases in aquaculture. However, prolonged antimicrobial use in aquaculture leads to public health hazards by developing antimicrobial-resistant pathogens that can cause infections in humans and animals. Multiple classes of antibiotics, such as fluoroquinolones, quinolones, tetracyclines, sulfonamides as well as nitrofurans and chloramphenicol, which are banned for use in food-producing animals in most countries, have been used in shrimp farming. Hence, the aquaculture industry may play a role in global AMR dissemination due to its direct connectivity to the aquatic environment and high levels of international shrimp trade. Under these circumstances, monitoring antimicrobial use (AMU) and antimicrobial resistance (AMR) in shrimp aquaculture is critically essential for interpreting AMR data and updating on the emergence of AMR, respectively. Nevertheless, various methodologies and standards have been used to study and report the antimicrobial susceptibility of bacteria isolated from shrimp and shrimp culture environments. Furthermore, lack of publications reported data on AMU and linkages between AMU and AMR frequencies observed. Limited information on harmonized and standardized methodologies to study AMU and AMR has been a great challenge to aquaculture researchers. More information is critically required to improve our understanding and enhance ongoing research work on AMU and AMR in shrimp aquaculture in Malaysia. Hence, we decided to explore and present an overview of methodologies and standards for monitoring AMU and AMR in shrimp aquaculture. Additional information about the knowledge, attitudes and practices (KAP) survey, antimicrobial residue testing, multiple antibiotic resistance (MAR) index, plasmid curing procedure, influence of seawater on the bioactivity of antimicrobials, whole genome sequencing (WGS), ethics approvals and biorisk management has also been included. To our knowledge, this review provides the first comprehensive information as a guide for conducting AMU and AMR studies in shrimp aquaculture. In addition, it is suitable to be adapted for use in other animal farming sectors and helps pave the way for the implementation of systematic biosecurity strategies on farms worldwide

Carotenoids modulate stress tolerance and immune responses in aquatic animals

Aquaculture continues to expand swiftly and remains the fastest-growing food industry worldwide amidst ever-present threats from chronic stressors and emerging diseases. Nutrition plays a pivotal role in the profitability and viability of the aquaculture industry that steered a paradigm shift to therapeutic nutrition. Carotenoids, also termed tetraterpenoids, have garnered considerable attention owing to their therapeutic attributes and immeasurable health benefits, which incited a surge in global demand. These biological pigments are recognized to promote immune systems and antioxidant defence mechanisms in both aquatic vertebrates and invertebrates. This review brings forth existing scientific evidence and underscores the notable roles of carotenoids as biologically active constituents with anti-stress and immunostimulatory potentials in farmed aquatic animals whilst explicating possible mechanisms of action. Empirical data unequivocally established the modulatory functions of carotenoids on endogenous antioxidant enzymes, innate and adaptive arms of the immune response, as well as the expression of multiple antioxidant and immune-related genes. The comprehensive information presented is beneficial to deepen our understanding of the utilization of carotenoids as potent stress alleviators and immunostimulants in cultured aquatic animals, which is translated into improved health. Advancements in aquatic animal health and welfare could principally contribute to reconstructing a more sustainable aquaculture industry. This article may be useful for subsequent investigations towards further advances in research and innovation to a greener blue revolution in solving the challenge of global food security

Significance of microalgal–bacterial interactions for aquaculture

Knowledge on the importance of associations between bacteria and microalgae in aquatic ecosystems is rather limited at the moment, mostly due to a lack of studies at the molecular and biochemical level of microorganisms. This paper discusses the current knowledge on microalgae–bacteria interactions and their potential impacts on the productivity, efficiency and sustainability of aquaculture. Current findings suggest that the interactions are complex and specific. The release of stimulatory products by bacteria that enhance the growth of microalgae, and vice versa, indicates the existence of mutualistic relations. Other factors, such as signalling between bacteria and microalgae, may also play an important role. Although these interactions may be of significant importance, to date, only a few findings have been reported on the use of consortia consisting of microalgae and bacteria for practical purposes. Interestingly, these results pointed out that a combination of microalgae and bacteria is often better than using either of them alone. Further research is needed to obtain a thorough understanding of the mechanisms behind the interactions between these microorganisms, including the identification of active compounds. This knowledge will enable the selection of appropriate consortia for different applications in aquaculture, including disease control and high and sustainable production of feed

Strategies of Controlling Vibriosis in Fish

The growth of the aquaculture industry is becoming more important in the food production sector. Presently, the biggest problem in aquaculture is bacterial diseases that infect the host thus causing outbreaks and economic losses. Vibriosis is a potentially lethal threat in commercial fish farming. Based on previous researches, various infections of the Vibrio genus have been reported hence their virulence is not fully understood. This review aims to provide enlightenment through research findings on Vibriosis-infected fish. Besides, some guidelines regarding control measures of Vibrio in aquaculture, such as the application of immunostimulant, antibiotics, probiotics and quorum sensing molecules, will be also reviewed.</jats:p