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1.
Heliyon ; 10(2): e25007, 2024 Jan 30.
Article in English | MEDLINE | ID: mdl-38312583

ABSTRACT

Fermented soybean products have played a significant role in Asian diets for a long time. Due to their diverse flavours, nutritional benefits, and potential health-promoting properties, they have gained a huge popularity globally in recent years. Traditionally, soybean fermentation is conducted spontaneously, using microorganisms naturally present in the environment, or inoculating with traditional starter cultures. However, many potential health risks are associated with consumption of these traditionally fermented soybean products due to the presence of food pathogens, high levels of biogenic amines and mycotoxins. The use of starter culture technology in fermentation has been well-studied in recent years and confers significant advantages over traditional fermentation methods due to strict control of the microorganisms inoculated. This review provides a comprehensive review of microbial safety and health risks associated with consumption of traditional fermented soybean products, and how adopting starter culture technology can help mitigate these risks to ensure the safety of these products.

2.
Front Microbiol ; 14: 1267227, 2023.
Article in English | MEDLINE | ID: mdl-37860141

ABSTRACT

Despite the advancements made in improving the quality of plant-based meat substitutes, more work needs to be done to match the texture, appearance, and flavor of real meat. This review aims to cover the sensory quality constraints of plant-based meat analogs and provides fermentation as a sustainable approach to push these boundaries. Plant-based meat analogs have been observed to have weak and soft textural quality, poor mouth feel, an unstable color, and unpleasant and beany flavors in some cases, necessitating the search for efficient novel technologies. A wide range of microorganisms, including bacteria such as Lactobacillus acidophilus and Lactiplantibacillus plantarum, as well as fungi like Fusarium venenatum and Neurospora intermedia, have improved the product texture to mimic fibrous meat structures. Additionally, the chewiness and hardness of the resulting meat analogs have been further improved through the use of Bacillus subtilis. However, excessive fermentation may result in a decrease in the final product's firmness and produce a slimy texture. Similarly, several microbial metabolites can mimic the color and flavor of meat, with some concerns. It appears that fermentation is a promising approach to modulating the sensory profiles of plant-derived meat ingredients without adverse consequences. In addition, the technology of starter cultures can be optimized and introduced as a new strategy to enhance the organoleptic properties of plant-based meat while still meeting the needs of an expanding and sustainable economy.

3.
Foods ; 12(17)2023 Aug 27.
Article in English | MEDLINE | ID: mdl-37685155

ABSTRACT

Plant-based meat analogs have been shown to cause less harm for both human health and the environment compared to real meat, especially processed meat. However, the intense pressure to enhance the sensory qualities of plant-based meat alternatives has caused their nutritional and safety aspects to be overlooked. This paper reviews our current understanding of the nutrition and safety behind plant-based meat alternatives, proposing fermentation as a potential way of overcoming limitations in these aspects. Plant protein blends, fortification, and preservatives have been the main methods for enhancing the nutritional content and stability of plant-based meat alternatives, but concerns that include safety, nutrient deficiencies, low digestibility, high allergenicity, and high costs have been raised in their use. Fermentation with microorganisms such as Bacillus subtilis, Lactiplantibacillus plantarum, Neurospora intermedia, and Rhizopus oryzae improves digestibility and reduces allergenicity and antinutritive factors more effectively. At the same time, microbial metabolites can boost the final product's safety, nutrition, and sensory quality, although some concerns regarding their toxicity remain. Designing a single starter culture or microbial consortium for plant-based meat alternatives can be a novel solution for advancing the health benefits of the final product while still fulfilling the demands of an expanding and sustainable economy.

4.
Crit Rev Food Sci Nutr ; : 1-23, 2023 Mar 14.
Article in English | MEDLINE | ID: mdl-36916137

ABSTRACT

Fermented soybean products, including Soya sauce, Tempeh, Miso, and Natto have been consumed for decades, mainly in Asian countries. Beans are processed using either solid-state fermentation, submerged fermentation, or a sequential of both methods. Traditional ways are still used to conduct the fermentation processes, which, depending on the fermented products, might take a few days or even years to complete. Diverse microorganisms were detected during fermentation in various processes with Bacillus species or filamentous fungi being the two main dominant functional groups. Microbial activities were essential to increase the bean's digestibility, nutritional value, and sensory quality, as well as lower its antinutritive factors. The scientific understanding of fermentation microbial communities, their enzymes, and their metabolic activities, however, still requires further development. The use of a starter culture is crucial, to control the fermentation process and ensure product consistency. A broad understanding of the spontaneous fermentation ecology, biochemistry, and the current starter culture technology is essential to facilitate further improvement and meet the needs of the current extending and sustainable economy. This review covers what is currently known about these aspects and reveals the limited available information, along with the possible directions for future starter culture design in soybean fermentation.

5.
Adv Nutr ; 14(1): 1-11, 2023 01.
Article in English | MEDLINE | ID: mdl-36811582

ABSTRACT

Food security has become a pressing issue in the modern world. The ever-increasing world population, ongoing COVID-19 pandemic, and political conflicts together with climate change issues make the problem very challenging. Therefore, fundamental changes to the current food system and new sources of alternative food are required. Recently, the exploration of alternative food sources has been supported by numerous governmental and research organizations, as well as by small and large commercial ventures. Microalgae are gaining momentum as an effective source of alternative laboratory-based nutritional proteins as they are easy to grow under variable environmental conditions, with the added advantage of absorbing carbon dioxide. Despite their attractiveness, the utilization of microalgae faces several practical limitations. Here, we discuss both the potential and challenges of microalgae in food sustainability and their possible long-term contribution to the circular economy of converting food waste into feed via modern methods. We also argue that systems biology and artificial intelligence can play a role in overcoming some of the challenges and limitations; through data-guided metabolic flux optimization, and by systematically increasing the growth of the microalgae strains without negative outcomes, such as toxicity. This requires microalgae databases rich in omics data and further developments on its mining and analytics methods.


Subject(s)
COVID-19 , Microalgae , Refuse Disposal , Humans , Food , Artificial Intelligence , Multiomics , Pandemics , Machine Learning
7.
Curr Sports Med Rep ; 22(1): 29-35, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36606634

ABSTRACT

ABSTRACT: Survey study of training and practice paradigms and job satisfaction of dual-boarded emergency medicine (EM) and sports medicine (SM) physicians. The REDCap survey was sent to 193 American Board of EM members who hold a Certificate of Added Qualification in SM. A total of 124 EM/SM physicians responded (67.5% male). More than 70% completed three-year residencies while only 28.5% had an EM/SM residency faculty. One-quarter delayed fellowship after residency 6.45 years on average. Regarding their first job after fellowship, 27.6% practiced only EM, 54.5% practiced both EM and SM, and 12.2% practiced only SM. Regarding their current job, 29.1% practice only EM. 47.3% practice both EM and SM, and 20.9% practice only SM. Only 13.9% and 9.9% indicated they are unhappy with their first job and current job, respectively. There is significant variability in practice settings for EM/SM physicians with the overwhelming majority being happy with their career choices.


Subject(s)
Emergency Medicine , Internship and Residency , Physicians , Sports Medicine , Humans , Male , United States , Female , Education, Medical, Graduate , Job Satisfaction , Surveys and Questionnaires , Emergency Medicine/education , Sports Medicine/education
8.
ANZ J Surg ; 93(1-2): 65-75, 2023 01.
Article in English | MEDLINE | ID: mdl-36373495

ABSTRACT

BACKGROUND: Native skin flap necrosis is a potentially devastating complication following skin-sparing or nipple-sparing mastectomy with a reported incidence of as high as 30%. Treatment depends on the depth and extent of tissue necrosis and can range from dressings to surgical debridement and further reconstruction. This can have implications on patient physical and psychological wellbeing as well as cost of treatment. This study aims to identify and appraise cost-effective non-surgical adjuncts for the prevention of native skin flap necrosis. METHODS: A systematic review was performed using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement and structured around existing recommended guidelines. A search of MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature and ClinicalTrials.gov was performed with the medical subject headings 'mastectomy' and 'flap necrosis'. After exclusion, 12 articles were selected for review and analysed. RESULTS: A total of 8439 mastectomies were performed on 7895 patients. Preventative non-surgical adjuncts that demonstrated statistically significant reduction in mastectomy flap necrosis included topical nitroglycerin ointment (P = 0.000), closed-Incision negative pressure wound therapy (P = 0.000), topical dimethylsulfoxide ointment (P = 0.03), oral cilostazol (P = 0.032), and local heat pre-conditioning (P = 0.047). CONCLUSIONS: This study identifies multiple adjuncts that may aid in preventing mastectomy skin flap necrosis, especially in high-risk patients. Further studies could aim to define standardized protocols and compare the various adjuncts in different circumstances.


Subject(s)
Breast Neoplasms , Mammaplasty , Mastectomy, Subcutaneous , Skin Diseases , Vascular Diseases , Humans , Female , Ointments , Surgical Flaps/adverse effects , Mastectomy/adverse effects , Mastectomy/methods , Mastectomy, Subcutaneous/methods , Postoperative Complications/epidemiology , Vascular Diseases/etiology , Skin Diseases/surgery , Necrosis/etiology , Necrosis/prevention & control , Necrosis/surgery , Mammaplasty/adverse effects , Mammaplasty/methods , Breast Neoplasms/surgery , Retrospective Studies , Nipples/surgery
9.
Cureus ; 14(11): e31506, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36540456

ABSTRACT

Abortion is healthcare. Bodily autonomy is a fundamental human right. As chief resident physicians representing family medicine residency programs in the Greater Bay Area and Central California in the University of California San Francisco Family Medicine Alliance, we share a deep commitment to promoting health equity, advancing social justice, and eliminating health disparities. The 2022 Supreme Court decision in Dobbs v. Jackson Women's Health Organization to overturn Roe v. Wade contradicts the inherent rights of patients to make their own reproductive healthcare decisions. This is a clarion call for all people to engage in activities to raise awareness and prompt discussion about abortion, reproductive rights, and maternal mortality.

10.
J Racial Ethn Health Disparities ; 9(5): 1873-1881, 2022 10.
Article in English | MEDLINE | ID: mdl-34342867

ABSTRACT

BACKGROUND: Chronic Hepatitis B virus infection, the leading cause of hepatocellular carcinoma worldwide, disproportionately affects Asian Pacific Islanders (APIs) within the USA. Among APIs, the Hmong have one of the highest rates of chronic HBV infection-up to 18% compared to 0.1% for non-Hispanic Caucasians. This study sought to estimate the prevalence of HBV infection and assess the need for community HBV education within Milwaukee County's Hmong. METHODS: Between 3/2013 and 12/2019, 287 Hmong participants were screened for HBV and 271 were provided targeted HBV education to evaluate its impact on HBV knowledge. RESULTS: Among participants screened, 178 (62%) were immune; 77 (27%) susceptible; 27 (9%) positive; and 5 (2%) in a "gray zone." Targeted health education showed statistically significant improvement in HBV knowledge. DISCUSSION: With 38% lacking immunity to HBV and 9% with active infection, there remains a significant need for HBV screening, vaccination, and education in Milwaukee's Hmong community.


Subject(s)
Asian , Health Education , Hepatitis B, Chronic , Needs Assessment , Asian/education , Asian/statistics & numerical data , Disease Susceptibility/ethnology , Hepatitis B virus/isolation & purification , Hepatitis B, Chronic/ethnology , Humans , Prevalence
11.
Am J Emerg Med ; 50: 679-682, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34879486

ABSTRACT

BACKGROUND: The emergency department (ED) is a stressful environment for children. Few studies assess pediatric anxiety in the ED. "Gold standard" for measuring state-anxiety, Spielberger's State-Trait Anxiety Inventory for Children (STAI-C state), is lengthy and of limited use in this setting. OBJECTIVE: The objective was to evaluate agreement between STAI-C, Likert, and modified Yale Preoperative Anxiety Scale (m-YPAS) and determine if shorter measures may be adequate replacements for STAI-C in the ED. METHODS: This is a secondary analysis of data from a previous observational cohort study of a convenience sample of children 5-17 years old presenting to the ED. Anxiety was measured using STAI-C, Likert, and m-YPAS. Spearman correlations were used to evaluate agreement between STAI-C and the brief scales. A sub-analysis evaluated agreement between scales for children ≥9 years old to assess the impact of age. RESULTS: Eighty children were included. Median (IQR) STAI-C state score was 32.5 (30.0, 37.8). This represents moderate state anxiety with 30% of children exhibiting elevated state anxiety. Median (IQR) Likert score was 2.0 (1.0, 2.0). Correlation between the Likert and STAI-C was moderate (rs = 0.51; p < 0.0001). Median (IQR) m-YPAS was 28.3 (24.2, 33.3). The m-YPAS and STAI-C were unrelated (rs = 0.12; p > 0.05). For children ≥9 years old, correlation between Likert and STAI-C remained moderate (rs = 0.52; p < 0.0001); STAI-C and m-YPAS were unrelated (rs = 0.10; p > 0.05). CONCLUSIONS: Children in the ED experienced moderate-elevated state anxiety. Likert scale may be an acceptable substitute for STAI-C state. Further studies of this scale will aid in identifying patients with anxiety to facilitate timely management.


Subject(s)
Anxiety/diagnosis , Emergency Service, Hospital , Adolescent , Age Factors , Child , Child, Preschool , Cohort Studies , Female , Humans , Male , Reproducibility of Results , Time Factors
12.
Curr Sports Med Rep ; 20(1): 31-46, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33395129

ABSTRACT

ABSTRACT: Musculoskeletal and sports medicine conditions are common in the emergency department (ED). Emergency physicians may not be receiving adequate education to achieve clinical competency in musculoskeletal medicine during residency training. This article aims to provide a standardized musculoskeletal and sports medicine curriculum for emergency medicine training. Broad curriculum goals include proficiency in evaluating and managing patients presenting to the ED with acute and chronic musculoskeletal complaints and other medical conditions related to or affected by physical exertion, sports participation, or environmental exposure. Specific objectives focus on knowledge of these disorders, physical examination skills, procedural skills including musculoskeletal ultrasound, appropriate consultation and referral, and patient education for these conditions. Educational methods will consist of didactics; online self-directed learning modules; simulation; and supervised clinical experiences in the ED, primary care sports medicine clinics, and orthopedic clinics if available. Curriculum implementation is expected to vary across programs due to differences in residency program structure and resources.


Subject(s)
Athletic Injuries/therapy , Clinical Competence , Curriculum/standards , Emergency Medicine/education , Internship and Residency , Musculoskeletal System/injuries , Sports Medicine/education , Diagnosis, Differential , Humans , Medical History Taking/standards , Physical Examination/standards
13.
ANZ J Surg ; 90(11): 2334-2339, 2020 11.
Article in English | MEDLINE | ID: mdl-33021039

ABSTRACT

BACKGROUND: In Australia, the rate of immediate breast reconstruction (IBR) following breast cancer surgery is highly variable. This study aimed to identify the rate of IBR within an Australian public tertiary breast oncology referral centre and analyse the tumour and demographic factors that impact upon IBR uptake. METHODS: A retrospective cohort study of 288 admissions of women requiring mastectomy between January 2012 and March 2015 was performed. Data collected included demographic data, tumour pathology, operative details and neoadjuvant therapy. Demographic data included a Socioeconomic Index for Area score, based on individual residential postcode, country of birth and need for an interpreter. RESULTS: Our study demonstrated an IBR rate of 41.3% and included a wide variety of reconstructions. Factors that increased the IBR rate included younger age and negative lymph node status. Our patient population was ethnically and linguistically diverse, with over 50 different countries of birth represented and with 53 patients requiring interpreters in 19 different languages. Our analysis shows that the requirement for an interpreter is negatively correlated with having an IBR. CONCLUSIONS: Our research demonstrates a high rate of IBR that includes a wide range of autologous and alloplastic reconstructions. Our study represents a unique opportunity to identify socioeconomic barriers that influence patient choice for reconstruction following mastectomy. This can lead to improved health care provision for our patients. This is particularly important in tertiary services with a strong multicultural and multi-linguistic population.


Subject(s)
Breast Neoplasms , Mammaplasty , Australia/epidemiology , Breast Neoplasms/epidemiology , Breast Neoplasms/surgery , Female , Hospitals, Public , Humans , Mastectomy , Retrospective Studies
15.
Trauma Case Rep ; 6: 8-12, 2016 Oct.
Article in English | MEDLINE | ID: mdl-29942852

ABSTRACT

INTRODUCTION: Fractures are known sequelae of seizures. We present a young male with bilateral acetabula and surgical neck of humerus (SNOH), right neck of femur (NOF) and thoracolumbar fractures in the context of a hypocalcaemic seizure secondary to severe malnutrition, secondary hyperparathyroidism and vitamin D deficiency. The authors believe that numerous severe injuries in a single patient secondary to seizure are extremely rare and have not been seen in the literature. CASE REPORT: A 25-year-old male presented to A&E following a collapse. He described limited movement and pain in all four limbs and collateral history described a generalised tonic-clonic seizure. XR and CT identified pelvic, femoral and humeral fractures, as well as compression fractures of T11, T12 and L1 vertebrae. His pelvic, femoral and SNOH fractures all required ORIF with intra-operative biopsy revealing abnormal bone quality. His spinal fractures did not require management.His young age and severe injuries prompted endocrinology and neurological evaluation. These revealed severe malnutrition secondary to behavioural and dietary factors with severe hypocalcaemia, secondary hyperparathyroidism and vitamin D deficiency. His metabolic and nutritional deficits were replaced intravenously and orally and his seizure attributed to hypocalcaemia. DISCUSSION AND CONCLUSION: Clinical suspicion for fractures should be high as the rate of fracture following seizure is approximately 6% [1]. Close evaluation and tertiary survey should be completed as missed musculoskeletal injury has been reported to be over 10% [2] and pre-existing medical and social risk factors may increase the incidence of these injuries [3-4].Given the young man's presentation, a high clinical suspicion was held for an underlying syndrome such as osteomalacia. Secondary to early aggressive treatment, a biopsy performed was non-diagnostic and features of osteomalacia were not present. Due to the potential consequences of a seizure, the authors recommend individuals who present with seizure or collapse be thoroughly examined and investigated to ensure no co-existing injury or pathology.

16.
Biotechnol Bioeng ; 112(10): 2163-71, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25855006

ABSTRACT

The microalga Dunaliella tertiolecta synthesizes intracellular glycerol as an osmoticum to counteract external osmotic pressure in high saline environments. The species has recently been found to release and accumulate extracellular glycerol, making it a suitable candidate for sustainable industrial glycerol production if a sufficiently high product titre yield can be achieved. While macronutrients such as nitrogen and phosphorus are essential and well understood, this study seeks to understand the influence of the micronutrient profile on glycerol production. The effects of metallic elements calcium, magnesium, manganese, zinc, cobalt, copper, and iron, as well as boron, on glycerol production as well as cell growth were quantified. The relationship between cell density and glycerol productivity was also determined. Statistically, manganese recorded the highest improvement in glycerol production as well as cell growth. Further experiments showed that manganese availability was associated with higher superoxide dismutase formation, thus suggesting that glycerol production is negatively affected by oxidative stress and the manganese bound form of this enzyme is required in order to counteract reactive oxygen species in the cells. A minimum concentration of 8.25 × 10(-5) g L(-1) manganese was sufficient to overcome this problem and achieve 10 g L(-1) extracellular glycerol, compared to 4 g L(-1) without the addition of manganese. Unlike cell growth, extracellular glycerol production was found to be negatively affected by the amount of calcium present in the normal growth medium, most likely due to the lower cell permeability at high calcium concentrations. The inhibitory effects of iron also affected extracellular glycerol production more significantly than cell growth and several antagonistic interaction effects between various micronutrients were observed. This study indicates how the optimization of these small amounts of nutrients in a two-stage system can lead to a large enhancement in D. tertiolecta glycerol production and should be considered during the design of a large scale bioprocess for this alternative route to glycerol.


Subject(s)
Carbon Dioxide/metabolism , Glycerol/metabolism , Micronutrients/metabolism , Volvocida/growth & development , Volvocida/metabolism , Biotransformation , Culture Media/chemistry , Metals/metabolism
17.
FEMS Microbiol Lett ; 357(2): 217-21, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24966133

ABSTRACT

Dunaliella accumulates intracellular glycerol to counterbalance the extracellular salinity. In N-limited chemostat cultures of D. tertiolecta, total glycerol production (sum of intracellular and extracellular) and intracellular glycerol content were proportional to the salinity of the culture medium. In the light-limited D. tertiolecta culture, total glycerol output (sum of intracellular and extracellular) was relatively constant at different salinities (0.5 and 2.0 M), while the intracellular glycerol content was proportional to the culture medium salinity, that is, the cells released less glycerol into the culture medium, rather than de novo synthesis of glycerol at high culture medium salinity. The study implies different regulatory mechanisms in the accumulation of intracellular glycerol in N-limited and light-limited D. tertiolecta in response to salinity.


Subject(s)
Biological Transport/radiation effects , Cell Membrane/metabolism , Glycerol/metabolism , Osmotic Pressure , Volvocida/physiology , Volvocida/radiation effects , Culture Media/chemistry , Light , Nitrogen/metabolism , Salinity , Stress, Physiological , Volvocida/metabolism
18.
BMC Genomics ; 14: 715, 2013 Oct 19.
Article in English | MEDLINE | ID: mdl-24138407

ABSTRACT

BACKGROUND: Neutral lipid storage is enhanced by nitrogen deprivation (ND) in numbers of green microalgal species. However, little is known about the metabolic pathways whose transcription levels are most significantly altered following ND in green microalgae, especially the nonmodel species. RESULTS: To start gaining knowledge on this, we performed transcriptome profiling of the nonmodel green microalga Botryosphaerella sudeticus cells in response to ND. Transcriptome of B. sudeticus is de novo assembled based on millions of HiSEQ short sequence reads using CLC Genomics Workbench software. The resulting non-redundant ESTs are annotated based on the best hits generated from the BLASTX homology comparison against the "best" proteins in the model microalgae Chlamydomonas reinhardtii and Chlorella variabilis. By using a pathway-based approach according to KEGG databases, we show that ESTs encoding ribosomal proteins and photosynthetic functions are the most abundantly expressed ESTs in the rapidly growing B. sudeticus cells. We find that ESTs encoding photosynthetic function but not the ribosomal proteins are most drastically downregulated upon ND. Notably, ESTs encoding lipid metabolic pathways are not significantly upregulated. Further analyses indicate that chlorophyll content is markedly decreased by 3-fold and total lipid content is only slightly increased by 50%, consistent with the transcriptional profiling. On the other hand, carbon content and photosynthesis efficiency are only marginally decreased by 7% and 20%, respectively, indicating that photosynthesis is only slightly reduced upon drastic downregulation of photosynthetic ESTs and chlorophyll content upon ND. In addition, TAG content is found to be greatly increased by 50-fold, though total lipid content is only slightly increased by 1.5-fold. CONCLUSIONS: Taken together, our results suggest that light-harvesting proteins and chlorophylls are in excess in B. sudeticus. Degradation of excess photosynthesis proteins is most likely a mechanism for recycling of nitrogen-rich molecules to synthesize new proteins for preparation of gametogenesis and zygospore formation in adaptation and survival upon ND. Furthermore, our analyses indicate that TAG accumulation is largely attributed to the modification of other pre-existing lipid molecules, rather than de novo synthesis. We propose that this is likely an evolutionarily conserved mechanism in many green microalgae species.


Subject(s)
Chlorophyta/genetics , Chlorophyta/metabolism , Gene Expression Profiling , Nitrogen/metabolism , Photosynthesis/genetics , Transcriptome , Cluster Analysis , Energy Metabolism/genetics , Expressed Sequence Tags , Gametogenesis , Gene Expression Regulation, Plant , Lipid Metabolism , Metabolic Networks and Pathways , Molecular Sequence Annotation , Ribosomal Proteins/genetics
19.
Bioresour Technol ; 136: 550-5, 2013 May.
Article in English | MEDLINE | ID: mdl-23567730

ABSTRACT

Microalgae have high photosynthetic efficiencies and produce many valuable compounds from carbon dioxide. The Dunaliella genus accumulates glycerol, yet no commercial process currently exists for glycerol production from this microalga. Here it was found that in addition to intracellular accumulation, Dunaliella tertiolecta also releases glycerol into the external medium continuously, forming a large and stable carbon pool. The process is not affected by nutrient starvation or onset of cell death. Carbon dioxide was fixed at a constant rate, the bulk of it being channelled to extracellular glycerol (82%), resulting in enhanced photosynthetic carbon assimilation of 5 times that used for biomass production. The final extracellular glycerol concentration was 34 times the maximum concentration of intracellular glycerol; the latter declined further during cell death. Findings from this work will assist in the development of a bioconversion process to produce glycerol using D. tertiolecta without the need for cell harvest or disruption.


Subject(s)
Carbon Dioxide/metabolism , Glycerol/metabolism , Microalgae/metabolism , Biomass , Carbon/metabolism , Extracellular Space/metabolism , Kinetics , Microalgae/cytology , Microalgae/growth & development
20.
FEBS J ; 280(4): 1064-72, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23279806

ABSTRACT

The unicellular halotolerant green alga species Dunaliella are able to proliferate in extremely varied salinities by synthesizing intracellular glycerol and adjusting the cell shape and volume. However, some marine Dunaliella species such as Dunaliella tertiolecta are not able to regulate cell volume as an immediate response to counter external osmotic shock. Here we report that a rapid shock-response mechanism is present in Dunaliella tertiolecta, involving uptake of exogenous glycerol in response to hyperosmotic shock without changing cell volume, and this glycerol uptake activity is associated with the Dunaliella tertiolecta glycerol uptake protein 1 (DtGUP1) gene, which belongs to the membrane-bound O-acyltransferase. The mutant DtGUP1-E, in which the DtGUP1 gene is silenced, displayed an inability to take up glycerol from the medium and showed cell death under hyperosmotic shock. To our knowledge, this is the first time a gene product has been reported in Dunaliella tertiolecta that is involved in glycerol uptake activity under hyperosmotic stress.


Subject(s)
Chlorophyta/metabolism , Glycerol/metabolism , Chlorophyta/genetics , Chlorophyta/physiology , Gene Expression Regulation, Plant , Gene Knockdown Techniques , Kinetics , Osmotic Pressure , Plant Proteins/genetics , Plant Proteins/metabolism , RNA Interference , RNA, Small Interfering/genetics , Sequence Analysis, DNA , Stress, Physiological , Transcriptional Activation
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