Economy and diversity of aquaculture production in Bulgaria: status and trends

Aquaculture production in Bulgaria has increased over the last decade, reaching 16 442 tonnes in 2019. Fish production has doubled in comparison with 2007, while that of mussels has increased tenfold. The Bulgarian contribution to EU aquaculture production has been increasing significantly in both volume and value over the years, making up 1.15% of the volume and 1.0% of the value of EU production in 2019. Freshwater aquaculture accounts for 78% of total production. Common carp dominates with about 29.4% (4836 t), followed by rainbow trout with 29.2% (4820 t) in 2019. The cultivation of sturgeon species and caviar production are among the most dynamically developing aquaculture segments. Mariculture in the Black Sea has increased in recent years, with the production of Mediterranean mussel reaching 2932 tonnes in 2019. An average of 405 farms operated during the period 2010-2019. Four regions (Plovdiv, Stara Zagora, Burgas and Montana) account for 50% of the total fish production. Pond aquaculture is the dominant technology used in Bulgaria, and it serves as the basis for numerous other activities, including management of fish stocks in various water bodies mainly for recreational fishing. Approximately 35 net-cage farms currently operate in bigger dams. Recirculating fish farms output made up only 0.15% of the total amount of aquaculture for the period 2010-2019. The aquaculture sector exhibited difficulties in recovering from the financial crisis of 2007-2008, manifested by a slow growth for the period 2010-2014. From 2015 to 2019 there has been a significant growth, manifested in a sharp increase of total revenue and profitability, especially among the larger enterprises in the sector, as well as an increase in the number of employees, and the labour productivity. As a result, in 2019 the registered total revenue per enterprise and total revenue per employee were more than double the respective figures for 2010. The profits of larger enterprises increased more than three times on average, but smaller entities, micro-enterprises with less than 5 employees, operated at the border line between profit and loss. The COVID-19 crisis could have lasting consequences. Despite EUR 1.2 million direct payments in the sector in 2020, there has been a significant drop in the export of aquaculture products. Consumption of fish and other aquaculture products remains low compared to those in the other EU countries.

Assessing the Spontaneous Spread of Climate-Adapted Woody Plants in an Extensively Maintained Collection Garden

Climate change may strongly modify the habitat conditions for many woody plant species. Some species could disappear from their natural habitats and become endangered, while others could adapt well to the changed environmental conditions and continue to survive successfully or even proliferate more easily. A similar process can occur within the artificial urban environment as the hitherto popularly planted urban trees may suffer from the extremities of the urban climate. However, among the planted taxa, there are species that spread spontaneously and appear as weeds in extensively managed gardens. In our study, we evaluated the native and non-native species involved in spontaneous spreading in the institutional garden of Buda Arboretum (Budapest) during the COVID-19 period in 2020–2021 when entry was prohibited, and maintenance went on in a restricted, minimal level. We investigated the correlation between spontaneously settling and planted individuals, and then performed multivariate analyses for native and non-native spreading plants for spatial and quantitative data. During our studies, we observed the spontaneous spreading of 114 woody species, of which 38 are native and 76 are non-native. Taking the total number of individuals into account, we found that, in addition to the 2653 woody species planted, a further 7087 spontaneously emerged weeds developed, which creates an additional task in the maintenance. © 2023 by the authors.

COVID-19 impacts on United States crawfish. (Special Issue: COVID-19 impacts on selected commodities.)

This research determines the impacts of COVID-19 US on crawfish production and consumption for 2020 and 2021 using an Equilibrium Displacement Model. In the US, crawfish is one of the seafood commodities where most production is consumed by domestic consumers (7% of domestic consumption is from imports). Crawfish and rice are complementary. Therefore, the impacts of COVID-19 on crawfish consumption simultaneously influence rice production and crawfish producers and consumers. In the first year of COVID-19 (2020), the reduction in crawfish retail demand caused negative effects on final consumers and producers. However, crawfish consumption recovered significantly in the second year (2021), which could compensate for the loss in 2020. Overall, consumer and producer gains ranged from $549 to $626 million if the COVID-19 pandemic only impacted retail consumption. However, in 2021, the increase in production costs due to higher oil/diesel prices and other input prices caused the farm supply to decrease. As a result, total welfare gains ranged from $200 to $228 million. If the demand in 2021 did not increase, but the crawfish farm supply decreased, consumer and producer losses ranged from $929 to $1045 million. Overall, the total effects of COVID-19 on consumers and producers for 2020 and 2021 depend on its effects in 2021. If the demand in 2021 increased following the decrease in farm supply, consumers and producers would benefit from the shocks of COVID-19 due to higher post-COVID-19 demand.

Pharmacological Properties and Safe Use of 12 Medicinal Plant Species and Their Bioactive Compounds Affecting the Immune System

This paper presents raw plant materials and their characteristic compounds which may affect the immune system. Plant-derived agents in specific doses affect the body's non-specific, antigen-independent defense system. They have immunostimulatory effects on the entire immune regulatory system. They can enhance the immune response through various factors such as macrophages, leukocytes, and granulocytes, as well as through mediators released by the cellular immune system. This paper was inspired by the threats caused by the COVID-19 pandemic. The proper functioning of the immune system is important in limiting the effects of viral infection and restoring the normal functioning of the body. This paper also emphasizes the importance of the skillful use of plant immunostimulants by potential patients, but also by those who prescribe drugs. It is important not only to choose the right plant drug but above all to choose the correct dose and duration of treatment.

MicroRNAs: The Master Regulators of the Breast Cancer Tumor Microenvironment

Breast cancer is the most commonly diagnosed cancer globally and is among the leading causes of cancer deaths worldwide. Breast cancer mortality rates are increasing due to delays in diagnosis, prognosis, and treatment caused by the coronavirus disease 2019 (COVID-19) pandemic. Identification and validation of blood-based breast cancer biomarkers for early detection is a top priority worldwide. MicroRNAs (miRNAs) show the potential to serve as breast cancer biomarkers. miRNAs are small, endogenously produced RNAs that regulate growth and development. However, oncogenic miRNAs also play a major role in tumor growth and can alter the tumor microenvironment (TME) in favor of cancer metastasis. The TME represents a complex network of diverse cancerous and noncancerous cell types, secretory proteins, growth factors, and miRNAs. Complex interactions within the TME can promote cancer progression and metastasis via multiple mechanisms, including oxidative stress, hypoxia, angiogenesis, lymphangiogenesis, and cancer stem cell regulation. Here, we decipher the mechanisms of miRNA regulating the TME, intending to use that knowledge to identify miRNAs as therapeutic targets in breast cancer and use miRNAs as blood-based biomarkers. © Springer Nature Singapore Pte Ltd. 2022.

What is hidden in the luggage? First assessments of illegal seashells gathering in Sardinia (Italy)

Natural souvenirs collection has been identified as a driving force in biodiversity and habitat degradation of tropical marine ecosystems. This work considers this phenomenon in the Mediterranean region taking Sardinia (Italy), one of the most renowned tourism destinations, as a case study. The biological material seized at Cagliari-Elmas Airport (years 2019–2020: 138 kg) was analyzed: 199 taxa were identified, gastropods (112 species, 7866 pieces) and bivalves (63 species, 34,218 pieces) resulted the most represented classes. Twenty-two protected species were found in the tourists' luggage including Patella ferruginea and Pinna nobilis, the invertebrates most threatened with extinction in the Mediterranean Sea. This study demonstrates that the illegal collection of natural mementos is common in Sardinia, thus its relevance is not limited to tropical regions. Regulation, enforcement and compliance shortcomings emerged, highlighting the importance of strengthening stakeholders' collaboration for a deeper insight on this phenomenon and implementing effective conservation strategies.

Impacts of COVID-19 on U.S. seafood availability. (Special Issue: COVID-19 impacts on selected commodities.)

Seafood is the food group with the highest share traded, and the U.S. is the world's largest seafood importer, importing 79% of the seafood consumed. Hence, a study examining the impacts of the measures to contain COVID-19 on U.S. seafood imports will not only show how U.S. seafood availability has been affected, but will also give strong indications of how resiliently the global seafood markets have worked through the pandemic. We find that U.S. imports of seafood actually increased in 2020 and 2021, suggesting supply chains were able to adapt to potential disruptions. Moreover, for the 14 largest product forms imported to the U.S., there are no strong price movements. Given that there is a global market for most species groups, this adaption also suggests that the markets have worked quite well beyond the U.S. Hence, while there have undoubtedly been market shocks associated with the COVID-19 measures such as the reduction in demand from the restaurant sector and the increased sales in the retail sector, opportunities seem to balance out challenges, and the supply chains for seafood to the U.S. have been highly resilient.

Special Issue: COVID-19 impacts on selected commodities. (Special Issue: COVID-19 impacts on selected commodities.)

This special issue consists of seven articles examining the impacts of the COVID-19 pandemic on the markets of selected commodities, including: seafood, lumber, crawfish, cattle/beef, fruits and vegetables in the USA, cotton and garments in Bangladesh, and fuel oil globally.

The coronavirus recombination pathway.

Recombination is thought to be a mechanism that facilitates cross-species transmission in coronaviruses, thus acting as a driver of coronavirus spillover and emergence. Despite its significance, the mechanism of recombination is poorly understood, limiting our potential to estimate the risk of novel recombinant coronaviruses emerging in the future. As a tool for understanding recombination, here, we outline a framework of the recombination pathway for coronaviruses. We review existing literature on coronavirus recombination, including comparisons of naturally observed recombinant genomes as well as in vitro experiments, and place the findings into the recombination pathway framework. We highlight gaps in our understanding of coronavirus recombination illustrated by the framework and outline how further experimental research is critical for disentangling the molecular mechanism of recombination from external environmental pressures. Finally, we describe how an increased understanding of the mechanism of recombination can inform pandemic predictive intelligence, with a retrospective emphasis on SARS-CoV-2.

Successful management of life-threatening post-COVID-19 cryptosporidiosis in a renal transplant patient: a case report.

Worldwide, Cryptosporidium spp. is a common parasite that affects domestic and wild animals, including humans, and causes diarrhea in both immunocompetent and immunocompromised hosts. The fecal-oral pathway accounts for the majority of its transfer. Although C. parvum and C. hominis are the most common zoonotic species in humans, other zoonotic species can also infect immunocompetent and immunocompromised people. Patients undergoing renal transplants are more likely to contract cryptosporidiosis, which can cause severe and potentially fatal diarrhea. A 41-year-old male patient who presented to the emergency department complained of a sudden onset, severe and continuous fatigue, and a feverish sensation of two-day duration. Two days prior to the current admission, the patient started to complain of weakness affecting his whole body, as well as a fever of 39°C and continuous yellowish diarrhea occurring 4-5 times daily without blood. Stool analysis revealed a cryptosporidium infection. The patient underwent surgery for kidney transplantation. The donated kidney was the left one from his brother and was attached to the patient´s right groin. As illustrated by our example, cryptosporidiosis should be considered a significant cause of acute, persistent, watery diarrhea in immunocompromised kidney transplant recipients. Patients undergoing renal transplants should be instructed to wash their hands frequently, stay away from young animals, sick people, and swimming pools in order to lower their risk of infection.

Porcine Deltacoronaviruses: Origin, Evolution, Cross-Species Transmission and Zoonotic Potential.

Porcine deltacoronavirus (PDCoV) is an emerging enteropathogenic coronavirus of swine that causes acute diarrhoea, vomiting, dehydration and mortality in seronegative neonatal piglets. PDCoV was first reported in Hong Kong in 2012 and its etiological features were first characterized in the United States in 2014. Currently, PDCoV is a concern due to its broad host range, including humans. Chickens, turkey poults, and gnotobiotic calves can be experimentally infected by PDCoV. Therefore, as discussed in this review, a comprehensive understanding of the origin, evolution, cross-species transmission and zoonotic potential of epidemic PDCoV strains is urgently needed.

[Ferroptosis-associated lesion as a potential target for cardiovascular disease: A review].

Cell death is an important feature of the development of multicellular organisms, a critical factor in the occurrence of cardiovascular diseases. Understanding the mechanisms that control cell death is crucial to determine its role in the development of the pathological process. However, the most well-known types of cell death cannot fully explain the pathophysiology of heart disease. Understanding how cardiomyocytes die and why their regeneration is limited is an important area of research. Ferroptosis is an iron-dependent cell death that differs from apoptosis, necrosis, autophagy, and other forms of cell death in terms of morphology, metabolism, and protein expression. Ferroptotic cell death is characterized by the accumulation of reactive oxygen species resulting from lipid peroxidation and subsequent oxidative stress, which can be prevented by iron chelates (eg, deferoxamine) and small lipophilic antioxidants (eg, ferrostatin, liproхstatin). In recent years, many studies have been carried out on ferroptosis in the context of the development of atherosclerosis, myocardial infarction, heart failure, and other diseases. In addition to cardiovascular diseases, the review also presents data on the role of ferroptosis in the development of other socially significant diseases, such as COVID-19, chronic obstructive pulmonary disease. With the study of ferroptosis, it turned out that ferroptosis participates in the development of bacterial infection associated with the persistence in the host body of Pseudomonas aeruginosa. The review summarizes the recent advances in the study of ferroptosis, characterizing this type of cell death as a novel therapeutic target.

eDNA testing reveals surprising findings on fish population dynamics in Thailand.

COVID-19, a global health concern, has an effect on all aspects of the economy. The aquaculture and fishing industries were severely harmed as a result of the closures in multiple nations. Regular systems for inventory monitoring, production, and supply were disrupted. Cancellation of programmes for research, fieldwork, sampling, and tagging influences management-required data. For effective species management, fish dispersion assessments are indispensable. However, due to the difficulty of accessing sampling sites and the associated costs, there is frequently a lack of comprehensive information regarding the distribution and abundance of organisms. The COVID-19 prohibition made fish monitoring more problematic. Due to constant pressure, populations of the stone lapping minnow (Garra cambodgiensis), one of Thailand's overfished fish, are rapidly declining. Therefore, eDNA-based monitoring was devised and implemented to reveal the likely dispersal of the species in Thailand prior to and following the lockdown. At 28 locations within the Chao Phraya River Basin, water samples were collected. qPCR was used to determine the presence or absence of G. cambodgiensis in water samples. In 78 of 252 water samples, a wide range of computed copy numbers for G. cambodgiensis eDNA was observed. It was discovered that samples collected in 2021 (after the lockdown) contain a higher concentration of G. cambodgiensis eDNA than samples collected in 2018 or 2019 (prior to the lockdown). The closure appears to be a boon and may result in a substantial restocking of the fish we have studied. Overall, eDNA-based analysis is an extremely promising new survey instrument.

Corrigendum: Evolution, ecology, and zoonotic transmission of betacoronaviruses: a review.

[This corrects the article DOI: 10.3389/fvets.2021.644414.].

Luteolin Isolated from Juncus acutus L., a Potential Remedy for Human Coronavirus 229E.

The COVID-19 pandemic, caused by SARS-CoV-2, addressed the lack of specific antiviral drugs against coronaviruses. In this study, bioguided fractionation performed on both ethyl acetate and aqueous sub-extracts of Juncus acutus stems led to identifying luteolin as a highly active antiviral molecule against human coronavirus HCoV-229E. The apolar sub-extract (CH2Cl2) containing phenanthrene derivatives did not show antiviral activity against this coronavirus. Infection tests on Huh-7 cells, expressing or not the cellular protease TMPRSS2, using luciferase reporter virus HCoV-229E-Luc showed that luteolin exhibited a dose-dependent inhibition of infection. Respective IC50 values of 1.77 µM and 1.95 µM were determined. Under its glycosylated form (luteolin-7-O-glucoside), luteolin was inactive against HCoV-229E. Time of addition assay showed that utmost anti-HCoV-229E activity of luteolin was achieved when added at the post-inoculation step, indicating that luteolin acts as an inhibitor of the replication step of HCoV-229E. Unfortunately, no obvious antiviral activity for luteolin was found against SARS-CoV-2 and MERS-CoV in this study. In conclusion, luteolin isolated from Juncus acutus is a new inhibitor of alphacoronavirus HCoV-229E.

Bright photon upconversion in LiYbF4:Tm3+@LiYF4 nanoparticles and their application for singlet oxygen generation and in immunoassay for SARS-CoV-2 nucleoprotein.

Photon upconversion is an intensively investigated phenomenon in the materials sciences due to its unique applications, mainly in biomedicine for disease prevention and treatment. This study reports the synthesis and properties of tetragonal LiYbF4:Tm3+@LiYF4 core@shell nanoparticles (NPs) and their applications. The NPs had sizes ranging from 18.5 to 23.7 nm. As a result of the energy transfer between Yb3+ and Tm3+ ions, the synthesized NPs show intense emission in the ultraviolet (UV) range up to 347 nm under 975 nm excitation. The bright emission in the UV range allows for singlet oxygen generation in the presence of hematoporphyrin on the surface of NPs. Our studies show that irradiation with a 975 nm laser of the functionalized NPs allows for the production of amounts of singlet oxygen easily detectable by Singlet Oxygen Sensor Green. The high emission intensity of NPs at 800 nm allowed the application of the synthesized NPs in an upconversion-linked immunosorbent assay (ULISA) for highly sensitive detection of the nucleoprotein from SARS-CoV-2, the causative agent of Covid-19. This article proves that LiYbF4:Tm3+@LiYF4 core@shell nanoparticles can be perfect alternatives for the most commonly studied upconverting NPs based on the NaYF4 host compound and are good candidates for biomedical applications.

The Impact of Serum Levels of Reactive Oxygen and Nitrogen Species on the Disease Severity of COVID-19.

Elucidation of the redox pathways in severe coronavirus disease 2019 (COVID-19) might aid in the treatment and management of the disease. However, the roles of individual reactive oxygen species (ROS) and individual reactive nitrogen species (RNS) in COVID-19 severity have not been studied to date. The main objective of this research was to assess the levels of individual ROS and RNS in the sera of COVID-19 patients. The roles of individual ROS and RNS in COVID-19 severity and their usefulness as potential disease severity biomarkers were also clarified for the first time. The current case-control study enrolled 110 COVID-19-positive patients and 50 healthy controls of both genders. The serum levels of three individual RNS (nitric oxide (NO•), nitrogen dioxide (ONO-), and peroxynitrite (ONOO-)) and four ROS (superoxide anion (O2•-), hydroxyl radical (•OH), singlet oxygen (1O2), and hydrogen peroxide (H2O2)) were measured. All subjects underwent thorough clinical and routine laboratory evaluations. The main biochemical markers for disease severity were measured and correlated with the ROS and RNS levels, and they included tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), the neutrophil-to-lymphocyte ratio (NLR), and angiotensin-converting enzyme 2 (ACE2). The results indicated that the serum levels of individual ROS and RNS were significantly higher in COVID-19 patients than in healthy subjects. The correlations between the serum levels of ROS and RNS and the biochemical markers ranged from moderate to very strongly positive. Moreover, significantly elevated serum levels of ROS and RNS were observed in intensive care unit (ICU) patients compared with non-ICU patients. Thus, ROS and RNS concentrations in serum can be used as biomarkers to track the prognosis of COVID-19. This investigation demonstrated that oxidative and nitrative stress play a role in the etiology of COVID-19 and contribute to disease severity; thus, ROS and RNS are probable innovative targets in COVID-19 therapeutics.

Native Cerrado vegetation is a haven for birds on the current trajectory of climate change

Resumo A mudanca climatica ja e vista como uma das maiores ameacas a biodiversidade no seculo XXI. Poucos estudos direcionam a atencAo para seus efeitos em comunidades inteiras de hotspots ameacados. Neste trabalho, combinamos a modelagem de nicho climatico (ENM) com um futuro cenario climatico de emissoes de gases de efeito estufa para estudar as futuras mudancas na diversidade alfa e beta das aves do bioma Cerrado brasileiro, um hotspot da biodiversidade com alta velocidade de mudanca climatica e expansAo agricola. Esperavamos que o sul do Cerrado (altamente modificado) apresentasse a maioria das mudancas negativas. Em geral, encontramos resultados heterogeneos para mudancas na riqueza de especies, na diversidade beta taxonomica e funcional espacial e temporal, e na diferenciacAo ecologica media. Analisamos 1301 aves, 1115 Menos Preocupantes, 83 Quase Ameacadas, 63 Vulneraveis, 33 Em Perigo, cinco Criticamente em Perigo e duas Extintas na natureza. Ao contrario de um estudo anterior sobre mamiferos do Cerrado, espera-se que a riqueza de especies aumente no norte do Cerrado, onde a homogeneizacAo das comunidades (diminuicAo da rotatividade espacial) tambem deve ocorrer especialmente atraves de invasoes locais. Mostramos que a homogeneizacAo biotica crescente (similaridade entre as comunidades) ocorrera em dois grupos biologicos, mas atraves de subprocessos diferentes: extincoes locais para mamiferos e invasoes locais para aves. Acoes distintas de manejo da conservacAo devem ser direcionadas dependendo dos resultados das analises de diversidade alfa e beta espacial e temporal, por exemplo, controlando invasoes de especies no norte do Cerrado. Tambem mostramos prioridades em nivel de especies para as aves do Cerrado. Os estudos de conservacAo devem continuar estudando o Cerrado no Brasil mesmo durante a pandemia de covid, pois a situacAo ambiental no pais nAo e boa e os incentivos para estudos cientificos sAo quase inexistentes. Tambem consideramos que o norte do Cerrado poderia ser visto como um refugio potencial para outros grupos de organismos (morcegos, borboletas, sapos etc.). Portanto, e crucial que os tomadores de decisAo tomem medidas ambiciosas de conservacAo.

The inhibitory and inactivating effects of visible light on SARS-CoV-2: A narrative update.

Prior to the coronavirus disease-19 (COVID-19) pandemic, the germicidal effects of visible light (λ = 400 - 700 nm) were well known. This review provides an overview of new findings that suggest there are direct inactivating effects of visible light - particularly blue wavelengths (λ = 400 - 500 nm) - on exposed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virions, and inhibitory effects on viral replication in infected cells. These findings complement emerging evidence that there may be clinical benefits of orally administered blue light for limiting the severity of COVID-19. Possible mechanisms of action of blue light (e.g., regulation of reactive oxygen species) and important mediators (e.g., melatonin) are discussed.

[Research progress on the relationship between low-density neutrophils and infectious diseases]

Neutrophils play an important role in infectious diseases by clearing pathogens in the early stages of the disease and damaging the surrounding tissues along with the disease progress. Low-density neutrophils (LDNs) are a crucial and distinct subpopulation of neutrophils. They are a mixture of activated and degranulated normal mature neutrophils and a considerable number of immature neutrophils prematurely released from the bone marrow. Additionally, they may be involved in the occurrence and development of diseases through the changes in phagocytosis, the generation of reactive oxygen species (ROS), the enhancement of the ability to produce neutrophils extracellular traps and immunosuppression. We summarizes the role of LDNs in the pathogenesis and their correlation with the severity of infectious diseases such as COVID-19, severe fever with thrombocytopenia syndrome (SFTS), AIDS, and tuberculosis.