Arabidopsis BBX14 is involved in high light acclimation and seedling development

The development of photosynthetically competent seedlings requires both light and retrograde biogenic signaling pathways. The transcription factor GLK1 functions at the interface between these pathways and receives input from the biogenic signal integrator GUN1. BBX14 was previously identified, together with GLK1, in a core module that mediates the response to high light (HL) levels and biogenic signals, which was studied by using inhibitors of chloroplast development. Our chromatin immunoprecipitation-Seq experiments revealed that BBX14 is a direct target of GLK1, and RNA-Seq analysis suggests that BBX14 may function as a regulator of the circadian clock. In addition, BBX14 plays a role in chlorophyll biosynthesis during early onset of light. Knockout of BBX14 results in a long hypocotyl phenotype dependent on a retrograde signal. Furthermore, the expression of BBX14 and BBX15 during biogenic signaling requires GUN1. Investigation of the role of BBX14 and BBX15 in GUN-type biogenic (gun) signaling showed that the overexpression of BBX14 or BBX15 caused de-repression of CA1 mRNA levels, when seedlings were grown on norflurazon. Notably, transcripts of the LHCB1.2 marker are not de-repressed. Furthermore, BBX14 is required to acclimate plants to HL stress. We propose that BBX14 is an integrator of biogenic signals and that BBX14 is a nuclear target of retrograde signals downstream of the GUN1/GLK1 module. However, we do not classify BBX14 or BBX15 overexpressors as gun mutants based on a critical evaluation of our results and those reported in the literature. Finally, we discuss a classification system necessary for the declaration of new gun mutants.

COVID-19 Complications: Oxidative Stress, Inflammation, and Mitochondrial and Endothelial Dysfunction

SARS-CoV-2 infection, discovered and isolated in Wuhan City, Hubei Province, China, causes acute atypical respiratory symptoms and has led to profound changes in our lives. COVID-19 is characterized by a wide range of complications, which include pulmonary embolism, thromboembolism and arterial clot formation, arrhythmias, cardiomyopathy, multiorgan failure, and more. The disease has caused a worldwide pandemic, and despite various measures such as social distancing, various preventive strategies, and therapeutic approaches, and the creation of vaccines, the novel coronavirus infection (COVID-19) still hides many mysteries for the scientific community. Oxidative stress has been suggested to play an essential role in the pathogenesis of COVID-19, and determining free radical levels in patients with coronavirus infection may provide an insight into disease severity. The generation of abnormal levels of oxidants under a COVID-19-induced cytokine storm causes the irreversible oxidation of a wide range of macromolecules and subsequent damage to cells, tissues, and organs. Clinical studies have shown that oxidative stress initiates endothelial damage, which increases the risk of complications in COVID-19 and post-COVID-19 or long-COVID-19 cases. This review describes the role of oxidative stress and free radicals in the mediation of COVID-19-induced mitochondrial and endothelial dysfunction.

Detection of Fungal Diseases in Lettuce by VIR-NIR Spectroscopy in Aquaponics

One of the main challenges facing the development of aquaponics is disease control, due on one hand to the fact that plants cannot be treated with chemicals because they can lead to mortality in cultured fish. The aim of this study was to apply the visible-near-infrared spectroscopy and vegetation index approach to test aquaponically cultivated lettuce (Lactuca sativa L.) infected with different fungal pathogens (Aspergillus niger, Fusarium oxysporum, and Alternaria alternata). The lettuces on the third leaf formation were placed in tanks (with dimensions 1 m/0.50 m/0.35 m) filled up with water from the aquaponics system every second day. In this study, we included reference fungal strains Aspergillus niger NBIMCC 3252, Fusarium oxysporum NBIMCC 125, and Alternaria alternata NBIMCC 109. Diffuse reflectance spectra of the leaves of lettuce were measured directly on the plants using a USB4000 spectrometer in the 450-1100 nm wavelength range. In near-infrared spectral range, the reflectance values of infected leaves are lower than those of the control, which indicates that some changes in cell structures occurred as a result of the fungal infection. All three investigated pathogens had a statistically significant effect on leaf water content and water band index. Vegetative indices such as Chlorophyll Absorption in Reflectance Index (CARI), Modified chlorophyll absorption in reflectance index (MCARI), Plant Senescence Reflectance Index (PSRI), Red Edge Index (REI2), Red Edge Index (REI3), and Water band index (WBI) were found to be effective in distinguishing infected plants from healthy ones, with WBI demonstrating the greatest reliability.

Direct Application of 3-Maleimido-PROXYL for Proving Hypoalbuminemia in Cases of SARS-CoV-2 Infection: The Potential Diagnostic Method of Determining Albumin Instability and Oxidized Protein Level in Severe COVID-19

Oxidative stress and the albumin oxidized form can lead to hypoalbuminemia, which is a predisposing factor for reduced treatment effectiveness and an increased mortality rate in severe COVID-19 patients. The aim of the study is to evaluate the application of free radical 3-Maleimido-PROXYL and SDSL-EPR spectroscopy in the in vitro determination of ox/red HSA in serum samples from patients with SARS-CoV-2 infection. Venous blood was collected from patients intubated (pO₂ < 90%) with a positive PCR test for SARS-CoV-2 and controls. At the 120th minute after the incubation of the serum samples from both groups with the 3-Maleimido-PROXYL, the EPR measurement was started. The high levels of free radicals were determined through the nitroxide radical TEMPOL, which probably led to increased oxidation of HSA and hypoalbuminemia in severe COVID-19. The double-integrated spectra of 3-Maleimido-PROXYL radical showed a low degree of connectivity due to high levels of oxidized albumin in COVID-19 patients. The low concentrations of reduced albumin in serum samples partially inhibit spin-label rotation, with A_max values and ΔH₀ spectral parameters comparable to those of 3-Maleimido-PROXYL/DMSO. Based on the obtained results, we suggest that the stable nitroxide radical 3-Maleimido-PROXYL can be successfully used as a marker to study oxidized albumin levels in COVID-19.

The Serum Levels of the Heavy Metals Cu, Zn, Cd, and Pb and Progression of COPD-A Preliminary Study

There is evidence in previous studies that high levels of heavy metals may play a key role in the development of COPD due to the induction of chronic inflammation and oxidative stress. In this preliminary study, we used atomic absorption spectrophotometry to measure the levels of four heavy metals (Cu, Zn, Cd, and Pb) in blood serum of COPD patients and controls over 2 years. Clinical data on disease progression or absence were collected in patients living in the industrial region of Stara Zagora, Bulgaria. The mean values of Cu in the serum of patients with COPD and the control group were 374.29 ± 15.03 μg/L and 238.55 ± 175.31 μg/L, Zn—2010.435 ± 670.006 μg/L and 1672.78 ± 934.27 μg/L, Cd—0.334 ± 0.0216 μg/L and 0.395 ± 0.110 μg/L and Pb—0.0732 ± 0.009 μg/L and 0.075 ± 0.0153 μg/L. This is probably because these elements are biogenic and are used in the body for its anti-oxidant protection. In fact, it cannot be stated with certainty that elevated levels of Cu and Zn in the environment have a negative impact in COPD patients. There was a trend towards higher levels of the toxicants lead and cadmium in COPD patients compared to the control group of patients. There is a statistically unproven trend toward higher levels of lead and cadmium in COPD patients compared to controls, which to some extent supports our hypothesis that there is a relationship between environmental lead and cadmium levels and the COPD manifested. In COPD patients, a positive correlation was found between BMI and serum Cu levels (r = 0.413, p = 0.005). A higher concentration of serum Cu was found in men with BMI ≥ 30, compared to those with BMI < 30. There is also a positive correlation to a lesser extent between CRP and cadmium (r = 0.380; p = 0.019) and lead (r = 0.452; p = 0.004). The correlation of lead and cadmium with PSA also shows that these elements may also be associated with the presence of inflammatory processes. A significant negative correlation exists between Pb in the serum of patients with COPD and their blood hemoglobin (r = −356; p = 0.028). The results of our study suggest that higher doses of the trace elements Cu and Zn do not always have a negative effect in patients with COPD, while the toxicants Pb and Cd may be involved in COPD exacerbation and can be used as prognostic biomarkers for progression. Further studies are warranted to confirm these preliminary results.

Site-Directed Spin Labeling EPR Spectroscopy for Determination of Albumin Structural Damage and Hypoalbuminemia in Critical COVID-19

The main factors in the COVID-19 pathology, which can initiate extensive structural changes at the cellular and molecular levels, are the generation of free radicals in abnormal amounts, and oxidative stress. Under "oxidative shock" conditions, the proteins undergo various modifications that affect their function and activity, and as a result distribute malfunctioning protein derivatives in the body. Human serum albumin is a small globular protein characterized by a high overall binding capacity for neutral lipophilic and acidic dosage forms. The albumin concentration is crucial for the maintenance of plasma oncotic pressure, the transport of nutrients, amino acids, and drugs, the effectiveness of drug therapy, and the prevention of drug toxicity. Hypoalbuminemia and structural defects molecule in the protein suggest a risk of changed metabolism and increased plasma concentration of unbound drugs. Therefore, the albumin structural and functional changes accompanied by low protein levels can be a serious prerequisite for ineffective therapy, frequent complications, and high mortality in patients with SARS-CoV-2 infection. The current opinion aims the research community the application of Site-Directed Spin Labeling Electron Paramagnetic Resonance spectroscopy (SDSL-EPR) and 3-Maleimido-PROXYL radical in determining abnormalities of the albumin dynamics and protein concentrations in COVID-19 critical patients.

ACUTE IZONIAZID POISONING WITH PRESENTATION OF A CLINICAL CASE

Rimicid or isonide a group of medications which belong to anti-tuberculosis medicaments. The active substance isoniazid is used to treat pulmonary and extrapulmonary forms of tuberculosis, as well as prophylaxis in case of contact with infected individuals. Isoniazid is rapidly absorbed, reaching a maximum serum concentration in 2 hours, and penetrates all body fluids. The volume of distribution is approximately 0.6 l/kg. Isoniazid causes pyridoxine deficiency in two ways: - by hydrazones, isoniazid metabolites inhibit the pyridoxal kinase, which converts pyridoxine to the active form, pyridoxal-5-phosphate, and - pyridoxine deficiency disrupts the synthesis and metabolism of GABA, the main inhibitory mediator of the central nervous system. Isonicotinic acid poisoning metabolism is subject to individualized factors, and in some people, this metabolism can be in a significantly slower. A clinical case of poisoning with 30 tablets of Rimicid by a 16-year-old girl suicidal attempt was presented. The results of the TC analysis confirm intoxication with the drug, and the retrospective assessment of the concentration over a past period of time using the elimination half-life has revealed an extremely high dose of ingested isoniazid.

Lowering of cholesterol bioaccessibility and serum concentrations by saponins: in vitro and in vivo studies

Using an in vitro digestion model, we studied the effect of six saponin extracts on the bioaccessibility of cholesterol and saturated fatty acids (SFAs). In the absence of saponins, around 78% of the available cholesterol was solubilized in the simulated intestinal fluids. The addition of two extracts, Quillaja Dry (QD) and Sapindin (SAP), was found to decrease cholesterol bioaccessibility to 19% and 44%, respectively. For both extracts, the main mechanism of this effect is the displacement of cholesterol molecules from the bile salt micelles, leading to formation of cholesterol precipitates that cannot pass through the mucus layer of the intestine. QD decreased strongly the SFA bioaccessibility as well, from 69 to 9%, due to formation of calcium-SFA precipitates, while SAP had no effect on SFA. We studied the in vivo activity of QD and SAP extracts by measuring serum cholesterol in mice fed with experimental diets within a 7-day period. Both extracts were found to prevent dietary hypercholesterolemia in mice fed on a cholesterol-rich diet. The other saponin extracts did not show any significant effect in vitro and, therefore, were not studied in vivo. The cholesterol lowering ability of Sapindin extract is reported for the first time in the current study.

Recognition of Vipera ammodytes meridionalis neurotoxin vipoxin and its components using phage-displayed scFv and polyclonal antivenom sera

Vipoxin is a potent postsynaptic heterodimeric neurotoxin isolated from the venom of the Bulgarian snake Vipera ammodytes meridionalis, whose snakebites cause different and strongly manifested pathophysiological effects (neurotoxic, hemolytic, anticoagulant, convulsant, hypotensive, hyperglycemic etc.). The neutralization of snake toxins calls for extensive research through the application of different approaches: antibodies, non-immunologic inhibitors, natural products derived from plants and animals, as well as synthetic drugs. In this study, we applied naive Tomlinson I + J (Cambridge, UK) libraries to obtain recombinant human scFv antibodies against the vipoxin's two subunits--basic and toxic phospholipase A₂ (PLA₂) and acidic, non-toxic component. We found that 33 of more than hundred tested clones were positive and recognized vipoxin and its subunits. Enriched scFv-phage samples (1.2 × 10⁹ pfu/ml) were analyzed for their binding (ELISA) and enzyme-inhibiting abilities. Single chain Fv-phage clones--D₁₂, E₃, F₆, D₁₀ and G₅ exhihest binding affinity for the toxic component. Clones A₁, D₁₂ and C₁₂ recognized preferentially vipoxin's acidic component. Clones E₃, G₅ and H₄ inhibited the enzymatic activity of both vipoxin and its purified and separated toxic subunit to the highest extent. Six of the selected clones (E₃, G₅, H₄, C₁₂, D₁₀ and A₁₁) inhibited direct hemolytic activity of vipoxin and its pure PLA₂ subunit. The obtained specific scFv antibodies will be used for epitope mapping studies required to shed light on the role of the phospholipase A₂ activity for the vipoxin toxicity and its effective neutralization.

Cobalt-induced changes in the spleen of mice from different stages of development

Cobalt(II) accumulates in organs such as spleen, kidneys, heart, and liver. The aim of the present study was to investigate the effects of cobalt ethylenediamine tetraacetic acid (Co-EDTA) on spleen of developing mice. Pregnant BALB/c mice in late gestation were subjected to Co-EDTA treatment at daily doses of 75 or 125 mg/kg in drinking water, which continued until d 90 of the newborn pups. The newborn pups were sacrificed on d 18, 25, 30, 45, 60, and 90, which correspond to different stages of development. Spleens were excised, weighed, and processed for histological analysis. Spleen index (SI) was calculated as a ratio of spleen weight to body weight. Cobalt(II) bioaccumulation in spleen was determined using flame atomic absorption spectrometry (FAAS). Preliminary results showed that chronic treatment of mice with low- or high-dose Co-EDTA disturbed extramedullary hematopoiesis in the spleen. The number of megakaryocytes was reduced compared to controls. SI was also reduced in d 18 mice treated with low- or high-dose Co-EDTA. However, exposure to 75 mg/kg led to an increase of SI in all other experimental groups. FAAS analysis revealed significant cobalt(II) accumulation in spleen of treated mice. The Co(II) levels in spleens of d 18 mice were highest compared to other experimental groups, indicating that at this period mice are more sensitive to treatment. Exposure to cobalt-EDTA resulted in accumulation of Co(II) in spleen, altered SI, and hematopoiesis. Immature mice appear to be more sensitive to chronic treatment than adults.

Synthesis and Inhibiting Activity of Some 4-Hydroxycoumarin Derivatives on HIV-1 Protease

Six novel 4-hydroxycoumarin derivatives were rationally synthesized, verified, and characterized by molecular docking using crystal HIV-1 protease. Molecular docking studies predicted antiprotease activity of (7) and (10). The most significant functional groups, responsible for the interaction with HIV-1 protease by hydrogen bonds formation are pyran oxygen, atom, lactone carbonyl oxygen and one of the hydroxyl groups. The newly synthesized compounds were biologically tested in MT-4 cells for inhibiting HIV-1 replication, exploring the protection of cells from the cytopathic effect of HIV measured by cell survival in MTT test. One derivative -7 showed 76-78% inhibition of virus infectivity with IC(50) = 0.01 nM, much less than the maximal nontoxic concentration (1 mM). Antiprotease activity of 7 in two different concentrations was detected to be 25%. Nevertheless, the results of study of (7) encourage using it as a pharmacophore for further synthesis and evaluation of anti-HIV activity.

Comparison of biochemical parameters of Muscovy drake semen diluted and stored at 4°C in three buffers

A comparison study of biochemical parameters of semen from Muscovy drakes diluted and stored at 4 degrees C in three buffers--IMV-buffer (France), HIA-1 and AU (Bulgaria) was carried out. The ejaculates were collected twice a week from ten 1-year-old Muscovy drakes using laying Muscovy females as teaser. Semen was diluted immediately, respectively, with IMV-buffer, HIA-1 and AU, and cold-stored (4 degrees C) for 1, 3 and 6h. The intensities of oxygen uptake at the third hour in semen diluted, respectively, with IMV-buffer (200+/-1.6 nAO/10(9) spermcellsmin), with HIA (224+/-44 nAO/10(9) spermcellsmin) and with AU (238+/-48 nAO/10(9) spermcellsmin) were highly significant in comparison with neat semen (75+/-0.7 nAO/10(9)spermcellsmin). The observed intensity of fructolysis was highest when using AU, followed by HIA-1 and IMV-buffer. During the first hour of storage the level of pyruvic acid was significantly lower in semen diluted with Bulgarian extenders, and this stability for AU referred to the entire period. For lactic acid, the differences were not statistical significant. Our investigations do not show significant differences concerning the dynamics of inorganic phosphate and total lipids after dilution with all tested extenders. On the contrary, high increase of cholesterol efflux from spermatozoa to seminal plasma-diluents were obtained after 6 h of storage. All extenders, IMV-buffer (France), HIA-1 and AU (Bulgaria) for diluting and short time storage of semen from Muscovy drakes at 4 degrees C maintain the necessary comfort of energy metabolism of the spermatozoa.

[Clinical assessment in patients presenting brain metastases]

Over the period January 1988 to January 1998, in the clinic of emergency neurology and neurosurgery of the University Hospital "Queen Giovanna"--Sofia a total of 348 patients with brain tumors are hospitalized. Of them 329 cases are subjected to operation, and in 19 no surgery is undertaken. Forty-four patients with metastatic brain tumors are operated, and in 14 no operation is done. Of those operated 25 (56.8%) are men, and 19 (43.2%)--women. The mean age of male patients is 53.9 years, and of female patients--54.4 years. In 35 cases the metastases are supratentorially situated, and in eight--subtentorially (a female patient has both supra- and subtentorial metastases). Reoperation is performed in three patients, and one dies after the operation. In 13 cases (29.5%) the primary focus of lesion is known prior to operation. Of all patients included in the series 6 present pulmonary carcinoma (46%), 5--melanoma (30.8%), 2--breast carcinoma (15.4%), and one--carcinoma of the gastrointestinal tract (7.8%).

[Intracranial hemorrhages in patients being treatment with anticoagulants]

Over the period 1994-1998, five patients presenting coagulation status impairment in the course of sintrom treatment are hospitalized in the Clinic of Emergency Neurology and Neurosurgery. Three of them are with craniocerebral trauma (2 severe forms--score 5 by the Glasgow Coma Rating scale, and one mild form--score 15), one has spontaneous intracerebral hematoma, and one--acute hydrocephalus against the background of ruptured aneurysm of the basilar artery (score 4). Three patients are given sintrom treatment because of rheumatic heart disease (2 with mitral valve prosthetic replacement and one in the post-commissurotomy period), and two--because of absolute arrhythmia, complicated by systemic emboli in the extremities and/or pulmonary artery. Four patients are subjected to operation--2 with craniocerebral injury, one with intracerebral hematoma and one with acute hydrocephalus of which in two cases the outcome is fatal. One female patient presenting serious craniocerebral trauma is not operated (refusal by the relatives) and dies. The therapeutic approach to this contingent of patients is comprehensively discussed.

[Clinical studies of patients with spinal cord metastases]

Eighty-one patients with spinal-cord tumors are hospitalized in the Clinic of Emergency Neurology and Neurosurgery over the period 1988 through 1997. Of the total number, 74 patients of which 25 presenting metastases from neoplasms with primary location out of the central nervous system, are subjected to operation. There are 4 tumors involving the cervical segment, 1--cervicothoracic, 17--thoracic, 1--thoracolumbar, and 2--lumbar segment. Histological verification is done in all patients operated on. The indications for undertaking surgery in this particular contingent of patients are discussed.

[Practical guidelines for the management of closed spinal cord injuries]

The principles underlying the necessity of operative management in handling closed spinal cord trauma, its indications and types of operative interventions are comprehensively discussed. Under separate headings are described the peculiarities of the approach to injuries involving cervical, thoracic and lumbal segments of the vertebral column, with a summarization of currently used methods and procedures, contributing to the more complete functional recovery of the spine, preservation and creation of optimal conditions for regaining the functions of the spinal cord affected which in turn, renders easier the performing of daily living activities, precludes the development of a variety of complications in the body as a whole, and first and foremost, allows for early initiation of rehabilitation measures.

[The basic principles of diagnosis and treatment in emergency surgery]

A review of the literature is made, in the attempt to establish the principles of the diagnosis and treatment in emergency surgery. They are listed as follows: 1. To preserve patient life and evaluate the functional capacity of the organism; 2. To establish emergency diagnosis; 3. To choose the method of treatment; 4. Method of operation. The guidelines in emergency surgery is to develop and perfect new methods of operation and new technical facilities, to raise the professional skill of the surgeon and to improve the organization of work in surgical clinics and departments.