Co-occurrence between key HAB species and particle-attached bacteria and substrate specificity of attached bacteria in the coastal ecosystem.

The ecological dynamics of particle-attached bacteria (PAB) were observed through changes in the core phytoplankton phycosphere, and were associated with the dynamics of free-living bacteria (FLB) using metabarcoding and microscopic analyses over 210 days (with weekly sampling intervals) in the Jangmok coastal ecosystem, South Korea. Cluster analysis and non-metric multidimensional scaling classified the phytoplankton community into six groups comprising core phytoplankton species, including the harmful algal species Akashiwo sanguinea (dinoflagellate) in late autumn, Teleaulax amphioxeia (cryptomonads) in early winter and spring, Skeletonema marinoi-dohrnii complex (diatom) in winter, Pseudo-nitzschia delicatissima (diatom) in early spring, and diatom complexes such as Chaetoceros curvisetus and Leptocylindrus danicus in late spring. We identified 59 and 32 indicators in PAB and FLB, respectively, which rapidly changed with the succession of the six core phytoplankton species. The characteristics of PAB were mainly divided into "Random encounters" or "Attraction of motivation by chemotaxis." When Akashiwo sanguinea bloomed, bacteria of the genera Kordiimonas and Polaribacter, which are commonly observed in PAB and FLB, indicated "Random encounter" characteristics. In addition, Sedimenticola of PAB was uniquely presented in Akashiwo sanguinea, exhibiting characteristics of "Attraction of motivation by chemotaxis." In contrast, FLB followed the strategy of "Random encounters" because it was not affected by specific habitats and energy sources. Thus, many common bacteria were PAB and FLB, thereby dictating the bacteria's strategy of "Random encounters." "Attraction of motivation by chemotaxis" has characteristics of the species-specific interactions between PAB and specific harmful algal species, and is potentially influenced by organic matter of core phytoplankton cell surface and/or EPS released from phytoplankton.

Oxidative balance and mental health: Exploring the link between prooxidant-antioxidant balance and depression in hypertensive and normotensive individuals, accounting for sex differences.

BACKGROUND: Existing studies have suggested a link between oxidative stress levels and depression. Additionally, factors such as gender and conditions like hypertension have been shown to influence oxidative stress. This ten-year follow-up cohort study aims to examine the association between prooxidant-antioxidant balance (PAB) and the onset of depression and its symptoms in both hypertensive and normotensive individuals, while considering gender differences. METHODS: The data for this study was obtained from the Mashhad Stroke and Heart Atherosclerotic Disorder (MASHAD) study, a cohort study conducted in eastern Iran. Serum PAB levels were measured in 1702 hypertensive and 4096 normotensive individuals aged 35 to 65 years. After ten years, the participants' depression status was evaluated using the Beck questionnaire, and depression symptoms were investigated using the BDI-II structural model, which includes somatic, affective, and cognitive symptoms. RESULT: The analysis indicates that in hypertensive male participants, the highest tertile of PAB is associated with an increased risk of depression (ß: 1.22, 95 % CI: -0.046, 2.485; P = 0.059) and symptoms of depression, including cognitive (ß: 2.937, 95 % CI: 0.511, 5.362; P = 0.018) and somatic (ß: 2.654, 95 % CI: 0.37, 4.939; P = 0.023) symptoms. However, there was no significant association between affective symptoms and PAB tertiles. Additionally, there was no significant link between depression and depressive symptoms in female hypertensive and normotensive individuals. CONCLUSION: In male hypertensive patients, but not in normotensive individuals of both genders and hypertensive women, depression and its associated symptoms, including somatic and cognitive symptoms, are associated with elevated levels of oxidative stress, as evidenced by higher serum PAB values. PAB is not associated with affective symptoms. Future studies should focus on the gender-specific nature of this relationship and work to clarify its underlying mechanisms.

Pseudolaric Acid B Targets CD147 to Selectively Kill Acute Myeloid Leukemia Cells.

Acute myeloid leukemia (AML) is an aggressive blood cancer. With low survival rates, new drug targets are needed to improve treatment regimens and patient outcomes. Pseudolaric acid B (PAB) is a plant-derived bioactive compound predicted to interact with cluster of differentiation 147 (CD147/BSG). CD147 is a transmembrane glycoprotein overexpressed in various malignancies with suggested roles in regulating cancer cell survival, proliferation, invasion, and apoptosis. However, the detailed function of PAB in AML remains unknown. In this study, AML cell lines and patient-derived cells were used to show that PAB selectively targeted AML (IC50: 1.59 ± 0.47 µM). Moreover, proliferation assays, flow cytometry, and immunoblotting confirmed that PAB targeting of CD147 resulted in AML cell apoptosis. Indeed, the genetic silencing of CD147 significantly suppressed AML cell growth and attenuated PAB activity. Overall, PAB imparts anti-AML activity through transmembrane glycoprotein CD147.

Towards on-line cheese monitoring: Exploration of semi-hard cheeses using NIR and 1H NMR spectroscopy.

This study aims to investigate the potential of using advanced spectroscopies for cheese quality monitoring. For this purpose, six semi-hard cheeses manufactured using lactic acid bacteria (LAB) and/or propionic acid bacteria (PAB) were explored using near-infrared spectroscopy (NIRS) and Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. The spectral data were analyzed using principal component analysis for extraction of possible discriminative patterns in quality parameters. The results show that the green analytical, but primarily bulk-sensitive, NIRS method was able to discriminate the cheese varieties primarily due to differences in the first overtone CH stretching region between 1650 and 1720 nm, in particular by the lactate methylene absorption at 1674 nm. A total of 25 metabolites were identified in the 1H NMR spectra of the cheese extracts, several of which were associated with the LAB and PAB metabolic pathways. PAB-associated metabolites include propionate, acetate, and glutamate, while LAB-associated metabolites include lactate and acetoin among others.

The associations of oxidative stress and inflammatory markers with obesity in Iranian population: MASHAD cohort study.

BACKGROUND: Low-grade inflammation and stress oxidative condition play a role in the pathogenesis of obesity, and the serum levels of these markers, such as pro-oxidant-antioxidant balance (PAB), high-sensitivity C-reactive protein (hs-CRP), and uric acid may indicate obesity progression. In this study, we aimed to investigate the relationship between obesity with PAB, hs-CRP, and uric acid in the Iranian population. METHODS: This study was derived from the Mashhad Stroke and Heart Atherosclerotic Disorder (MASHAD) study. A total of 7985 subjects aged 35 to 65 years were divided into three groups according to body mass index (BMI) as: normal, overweight and obese groups. Anthropometric indices and biochemical parameters such as PAB, superoxide dismutase type 1 (SOD1), hs-CRP, and uric acid were measured in all the participants. We evaluated the association of obesity with inflammatory factors by using multivariate regression analysis. Also, those participants with hypertension, an endocrine disorder, history of cardiovascular diseases and diabetes mellitus were excluded from the study. RESULTS: There was a positive significant correlation between BMI and serum PAB, hs-CRP and uric acid (p < 0.001). While no statistically significant relation was observed between BMI and SOD1 (p = 0.85). Multivariate regression analysis showed that the risk of overweight and obesity increased 1.02 and 1.03-fold according to increase 10 units of PAB raise in comparison to reference group (normal weight) [(odds ratio (OR): 1.02, 95% CI (1.01-1.03)] and [OR: 1.03, 95% CI (1.01-1.04)], respectively). In addition, hs-CRP serum concentration was significantly associated with a high risk of obesity [(OR: 1.02; 95% CI (1.01-1.03)]. While the high levels of serum uric acid were associated with increased odds of overweight and obesity risk [OR: 1.4; CI (1.39-1.58) and OR: 1.76; CI (1.63-1.89), respectively]. CONCLUSIONS: Generally, we showed a significant association between BMI and serum PAB, hs-CRP values and uric acid levels, suggesting the role of these factors as risk stratification factors for obesity.

HDX-MS finds that partial unfolding with sequential domain activation controls condensation of a cellular stress marker.

Eukaryotic cells form condensates to sense and adapt to their environment [S. F. Banani, H. O. Lee, A. A. Hyman, M. K. Rosen, Nat. Rev. Mol. Cell Biol. 18, 285-298 (2017), H. Yoo, C. Triandafillou, D. A. Drummond, J. Biol. Chem. 294, 7151-7159 (2019)]. Poly(A)-binding protein (Pab1), a canonical stress granule marker, condenses upon heat shock or starvation, promoting adaptation [J. A. Riback et al., Cell 168, 1028-1040.e19 (2017)]. The molecular basis of condensation has remained elusive due to a dearth of techniques to probe structure directly in condensates. We apply hydrogen-deuterium exchange/mass spectrometry to investigate the mechanism of Pab1's condensation. Pab1's four RNA recognition motifs (RRMs) undergo different levels of partial unfolding upon condensation, and the changes are similar for thermal and pH stresses. Although structural heterogeneity is observed, the ability of MS to describe populations allows us to identify which regions contribute to the condensate's interaction network. Our data yield a picture of Pab1's stress-triggered condensation, which we term sequential activation (Fig. 1A), wherein each RRM becomes activated at a temperature where it partially unfolds and associates with other likewise activated RRMs to form the condensate. Subsequent association is dictated more by the underlying free energy surface than specific interactions, an effect we refer to as thermodynamic specificity. Our study represents an advance for elucidating the interactions that drive condensation. Furthermore, our findings demonstrate how condensation can use thermodynamic specificity to perform an acute response to multiple stresses, a potentially general mechanism for stress-responsive proteins.

Autophagy-mediated surveillance of Rim4-mRNA interaction safeguards programmed meiotic translation.

In yeast meiosis, autophagy is active and essential. Here, we investigate the fate of Rim4, a meiosis-specific RNA-binding protein (RBP), and its associated transcripts during meiotic autophagy. We demonstrate that Rim4 employs a nuclear localization signal (NLS) to enter the nucleus, where it loads its mRNA substrates before nuclear export. Upon reaching the cytoplasm, active autophagy selectively spares the Rim4-mRNA complex. During meiotic divisions, autophagy preferentially degrades Rim4 in an Atg11-dependent manner, coinciding with the release of Rim4-bound mRNAs for translation. Intriguingly, these released mRNAs also become vulnerable to autophagy. In vitro, purified Rim4 and its RRM-motif-containing variants activate Atg1 kinase in meiotic cell lysates and in immunoprecipitated (IP) Atg1 complexes. This suggests that the conserved RNA recognition motifs (RRMs) of Rim4 are involved in stimulating Atg1 and thereby facilitating selective autophagy. Taken together, our findings indicate that autophagy surveils Rim4-mRNA interaction to ensure stage-specific translation during meiosis.

Prognostic Factors Associated With Sleep Duration: Serum Pro-Oxidant/Antioxidant Balance and Superoxide Dismutase 1 as Oxidative Stress Markers and Anxiety/Depression.

Objectives: Sleep is a conserved vital behavior in humans, and insufficient sleep is associated with several disorders. Recent studies have investigated the association of sleep duration, oxidative stress markers, anxiety, and depression. Therefore, we aim to assess the relationship between sleep duration, serum pro-oxidant/antioxidant balance (PAB) and superoxide dismutase 1 (SOD1) levels as markers of oxidative stress, anxiety, and depression. Methods: Participants included in our cross-sectional analysis were recruited as part of the MASHAD study (n = 9,184). Nocturnal sleep duration was identified using a self-reported questionnaire, and serum pro-oxidant/antioxidant balance (PAB) and superoxide dismutase 1 (SOD1) levels were assessed using methods that have been previously reported. Results: Serum PAB, depression, and anxiety scores were found significantly higher in subjects with very short sleep duration. In an adjusted model using MANOVA regression analysis, serum PAB was significantly higher in the subjects with a very short sleep duration (p: 0.016 in depression and p: 0.002 in anxiety). Conclusion: The present cross-sectional study demonstrates a relationship between sleep duration, oxidative balance, and depression/anxiety, especially in anxiety subjects that might predict each other.

Prognostic value of preoperative prealbumin levels in patients with unresectable hepatocellular carcinoma undergoing transcatheter arterial chemoembolisation.

Background: This retrospective study analyzed the prognostic value of preoperative prealbumin (PAB) levels in patients with unresectable hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolisation (TACE). Methods: Four hundred and two patients diagnosed with unresectable HCC were included in this retrospective study. All patients underwent their first TACE procedure. Based on PAB levels before the first TACE, 402 patients were classified as having low PAB levels and high PAB levels. Potential confounding factors between the two groups were eliminated using. Propensity Score Matching (PSM) analysis. The time to progression (TTP) and overall survival (OS) of the two groups were compared using Kaplan-Meier curves before and after PSM. Risk factors for poor prognosis were determined using univariate and multivariate Cox proportional hazards models. Results: Before PSM, the high PAB level group had a significantly longer median TTP and OS than the low PAB level group (all P values < 0.0001). After PSM, the high PAB level group still had a significantly longer median TTP and OS than the low PAB level group (all P values < 0.05). After PSM, low PAB level was found to be an independent predictor of shorter OS (HR = 0.656; 95% CI:0.448-0.961; P = 0.03). The subgroup analysis before PSM showed that low PAB levels increased the risk of poor prognosis in most subgroups. Conclusions: Low preoperative PAB levels are associated with poor prognosis in patients with unresectable HCC after TACE.

Direct and indirect consequences of PAB1 deletion in the regulation of translation initiation, translation termination, and mRNA decay.

Cytoplasmic poly(A)-binding protein (PABPC; Pab1 in yeast) is thought to be involved in multiple steps of post-transcriptional control, including translation initiation, translation termination, and mRNA decay. To understand these roles of PABPC in more detail for endogenous mRNAs, and to distinguish its direct effects from indirect effects, we have employed RNA-Seq and Ribo-Seq to analyze changes in the abundance and translation of the yeast transcriptome, as well as mass spectrometry to assess the abundance of the components of the yeast proteome, in cells lacking the PAB1 gene. We observed drastic changes in the transcriptome and proteome, as well as defects in translation initiation and termination, in pab1Δ cells. Defects in translation initiation and the stabilization of specific classes of mRNAs in pab1Δ cells appear to be partly indirect consequences of reduced levels of specific initiation factors, decapping activators, and components of the deadenylation complex in addition to the general loss of Pab1's direct role in these processes. Cells devoid of Pab1 also manifested a nonsense codon readthrough phenotype indicative of a defect in translation termination, but this defect may be a direct effect of the loss of Pab1 as it could not be attributed to significant reductions in the levels of release factors.

Corrigendum: XAV-19, a swine glyco-humanized polyclonal antibody against SARS-CoV-2 spike receptor-binding domain, targets multiple epitopes and broadly neutralizes variants.

[This corrects the article DOI: 10.3389/fimmu.2021.761250.].

m6A readers ECT2/ECT3/ECT4 enhance mRNA stability through direct recruitment of the poly(A) binding proteins in Arabidopsis.

BACKGROUND: RNA N6-methyladenosine (m6A) modification is critical for plant growth and crop yield. m6A reader proteins can recognize m6A modifications to facilitate the functions of m6A in gene regulation. ECT2, ECT3, and ECT4 are m6A readers that are known to redundantly regulate trichome branching and leaf growth, but their molecular functions remain unclear. RESULTS: Here, we show that ECT2, ECT3, and ECT4 directly interact with each other in the cytoplasm and perform genetically redundant functions in abscisic acid (ABA) response regulation during seed germination and post-germination growth. We reveal that ECT2/ECT3/ECT4 promote the stabilization of their targeted m6A-modified mRNAs, but have no function in alternative polyadenylation and translation. We find that ECT2 directly interacts with the poly(A) binding proteins, PAB2 and PAB4, and maintains the stabilization of m6A-modified mRNAs. Disruption of ECT2/ECT3/ECT4 destabilizes mRNAs of ABA signaling-related genes, thereby promoting the accumulation of ABI5 and leading to ABA hypersensitivity. CONCLUSION: Our study reveals a unified functional model of m6A mediated by m6A readers in plants. In this model, ECT2/ECT3/ECT4 promote stabilization of their target mRNAs in the cytoplasm.

Comparing maternal and neonatal prooxidant-antioxidant balance during delivery

Objective: Oxidative stress (OS) is due to a disturbance in the balance between the production of free radicals and antioxidant defense, resulting in a predominance of free radicals over endogenous anti-oxidant defenses. OS may have many causes. Pregnancy, and especially delivery, are associated with increased OS. The relationship between maternal and infant prooxidant-antioxidant balance (PAB) is unclear. Therefore, the aim of the present study was to compare PAB in mother and baby pairs. Material and Methods: This cross-sectional study was conducted in 104 mothers and normal term infants during 2017-2020. PAB was measured in healthy mothers before delivery and in umbilical cord samples after delivery. Data on the infant characteristics including age, gestational age, birth weight, Apgar score, and maternal history including the duration of mother's education, weight of the last month, and gravidity were collected using a researcher-made questionnaire. The cord and maternal PAB were compared by statistical methods. Results: In this study, the mean PAB of the neonates and mothers was 30.76 and 214.87 HK, respectively. The results revealed a moderate association between the PAB neonate and maternal PAB before delivery but it was not significant. Conclusion: Overall, the level of oxidants and antioxidants reduced during pregnancy and before delivery, and it was found that the relative incidence of neonatal PAB increases by increasing maternal PAB.

Establishment of a novel 70K Mac-2 binding protein antibody through screening of fucosylation-related antibodies.

Mac-2 binding protein (Mac-2bp) is a serum glycoprotein that contains seven N-glycans, and Mac-2bp serum levels are increased in patients with several types of cancer and liver disease. Mac-2bp glycosylation isomer has been applied as a clinical biomarker of several diseases, including liver fibrosis. In the present study, we identified fucosylated Mac-2bp in the conditioned medium of cancer cells resistant to anticancer therapies using glycoproteomic analyses. Fucosylation is one of the most important types of glycosylation involved in carcinogenesis and cancer stemness. To establish a next-generation glycan antibody for fucosylated Mac-2bp, we used fucosylation-deficient HEK293T cells to prepare reference Mac-2bp antigens and performed antibody screening. Unexpectedly, the 19-8H mAb obtained with our screen recognized 70K Mac-2bp, which is C-terminus-truncated product, rather than specifically recognizing fucosylated Mac-2bp. We performed immunocytochemistry using our novel 19-8H mAb, which resulted in strong cell surface staining of anticancer drug-resistant cancer cells. Therefore, our novel 19-8H mAb represents a valuable tool for cancer biology research that can help elucidate the biological function of 70K Mac-2bp.

Oxidative Stress and Inflammatory Biomarkers in Patients with Diabetic Foot.

Background and Objectives: Diabetic foot (DF) development is driven by complex interactions of hyperglycemia, inflammation, and oxidative stress (OS). We aimed to investigate OS and inflammatory biomarkers in patients with DF and their potential to improve early diagnosis and management of DF. Materials and Methods: The prooxidant−antioxidant balance (PAB), superoxide dismutase (SOD), total oxidative status (TOS), total sulfhydryl groups (SHG), routine biochemical parameters, and complete blood count were determined in 42 patients with type-2 DM, of which 23 patients had DF, while 19 patients were without DF complications. The neutrophils-to-lymphocyte ratio (NLR) was evaluated as a biomarker of inflammation. Results: Patients with DF had significantly higher (p < 0.05) PAB levels (170 ± 33.9 U/L) compared to those without DF complications (142 ± 31.3 U/L). In addition, patients with DF had significantly reduced SOD activities (p < 0.01). NLR values were significantly higher in the DF group (median: 2.8; interquartile range: 2.0−4.3) than in the group without DF (median: 1.4; interquartile range: 1.4−2.1; p < 0.01). A positive correlation was found between the PAB and NLR index (r = 0.449; p < 0.05). The diagnostic accuracy of both PAB (AUC = 0.741; p < 0.01) and NLR (AUC = 0.760; p < 0.01) was estimated as acceptable. Conclusions: In conclusion, the development of DF is associated with enhanced OS and inflammation processes. PAB and NLR could be useful non-invasive biomarkers of DF development.

Safety evaluation of dried L-tryptophan fermentation product in Sprague-Dawley rats.

The subchronic toxicity of oral L-tryptophan produced by fermentation with metabolically engineered Corynebacterium glutamicum was evaluated in Sprague-Dawley rats. Doses of 0, 500, 1000, and 2000 mg/kg/day were administered to groups of 10 male and 10 female rats for 90 days. For the groups administered 0 and 2000 mg/kg/day, an additional 5 male and 5 female rats were tested as a recovery group. No adverse effects associated with the test substance were observed in all rats during the 90-day administration of the product, irrespective of dose, and at 4 weeks of recovery at dosages of 0 and 2000 mg/kg/day. Furthermore, histochemical and immunohistochemical analyses for L-tryptophan-associated eosinophilia-myalgia syndrome (EMS) did not reveal significant changes in both sexes of groups administered 0 or 2000 mg/kg/day. Based on these results, it could be concluded that there were no significant adverse effects related to the test substance in all animals; therefore, dried L-tryptophan fermentation product can be used as feed additive material.

Plant-Associated Bacteria as Sources for the Development of Bioherbicides.

Weeds cause significant yield losses in crop production and influence the health of animals and humans, with some exotic weeds even leading to ecological crises. Weed control mainly relies on the application of chemical herbicides, but their adverse influences on the environment and food safety are a significant concern. Much effort has been put into using microbes as bioherbicides for weed control. As plant-associated bacteria (PAB), they are widely present in the rhizophere, inside crops or weeds, or as pathogens of weeds. Many species of PAB inhibit the seed germination and growth of weeds through the production of phytotoxic metabolites, auxins, hydrogen cyanide, etc. The performance of PAB herbicides is influenced by environmental factors, formulation type, surfactants, additives, application methods, and cropping measures, etc. These factors might explain the inconsistencies between field performance and in vitro screening results, but this remains to be clarified. Successful bioherbicides must be specific to the target weeds or the coinciding weeds. Detailed studies, regarding factors such as the formulation, application techniques, and combination with cultivation measures, should be carried out to maximize the performance of PAB-based bioherbicides.

[What Works for Whom? Differential Effects of Predictive Validity of Parenting Behaviours: Externalizing Versus Internalizing Behaviour Problems]. / Was hilft bei wem? Unterschiedliche Auswirkungen der prädiktiven Validität von Erziehungsverhalten: Externalisierende versus internalisierende Verhaltensprobleme.

A variety of instruments are available for assessing parental and child behaviour in the context of interaction observation. This study investigated whether the Laboratory Parenting Assessment Battery (Lab-PAB) can be used to make predictive statements about the therapeutic success of child psychiatric treatment. The success of therapy was measured through pre- and post-intervention assessments using the Child Behavior Checklist (CBCL) and the Parent-Infant Relationship Global Assessment Scale (PIR-GAS). A particular focus was placed on discriminating between externalizing and internalizing problems of the child. It was observed that positive items of the interaction offer a greater resource for the therapeutic success of children with externalizing problems than stopping negative behaviour of the parents. In the case of internalizing problems, the elimination of negative interaction items seems to be essential for a good therapy success.

Concentration of human thymidine kinase 1 discover invisible malignant human tumours.

Early discover of risk progression of invisible carcinomas is important for a prerequisite successful treatment. Here, we investigated whether concentration of human thymidine kinase 1 (HTK1) discover invisible malignant human tumours. The HTK1 concentration of tumour cellular based on HTK1 IgY-polyclonal-antibody (HTK1-IgY-pAb) was determined by using a novel automatic chemiluminescence analyser with sandwich biotin-streptavidin (SBSA) platform. Minimum number of cells able to be detected by this technology used cells with low and high concentration of HTK1. The limit visibility by tumour imaging is approximately 1 mm in diameter, corresponding to approximately 109 cells with a cell diameter of 1 µm. Based on a HTK1 standard curve and a molecular weight of HTK1 of 96 kD, the HTK1protein (HTK1p) concentration per cell was calculated to be 0.021 pg. Assuming 200 pg in total protein/cell, approximately 50 × 106 growing malignant cells in the body were calculated to releases HTK1 into 5-liter blood. A HTK1 values of 3.914, 0.435 and 0.009 pmol/L corresponds to 10 × 105, 2 × 105 and 1 × 105 growing malignant cells, respectively. The lowest detectable sensitivity of HTK1 is 0.009 pmol/L in 1 × 105 growing malignant cells and 0.01 pmol/L in blood serum, detectable in health screening. Comparing the novel automatic chemiluminescence analyser with the original ECL dot-blot assay using serum HTK1p (health screening, n = 265) showed high correlation (r = 0.8743, P < .000). In conclusion, the novel automatic chemiluminescence analyser with SBSA platform is a reliable method with high accuracy to determine carcinoma invisible.

Role of anti-Giardia recombinant cyst wall protein IgG polyclonal antibodies in diagnosis and protection.

Giardia duodenalis (G. duodenalis) is an infectious protozoan that has a global distribution especially in the hot climate. Around 200 million people are infected worldwide annually by Giardia, but infection is not always accompanied by symptoms, especially in endemic countries. Using traditional microscopy techniques in diagnosis, both in stool and water samples were less sensitive when compared to immunological methods; and the need for new diagnostic methods was necessary. Also, protection from infection is required in endemic areas. Therefore, the study aimed to produce anti- G. duodenalis IgG polyclonal antibodies (pAbs) by immunizing rabbit by G. duodenalis cyst recombinant protein. The produced antibodies were evaluated in the detection of G. duodenalis antigens in patients' stool and water samples from endemic areas across River Nile; where pAbs were used as a coating and a peroxidase conjugate antibody in sandwich ELISA. Moreover, pAbs were tested for the protection of mice from giardiasis. Sandwich ELISA using pAb has succeeded in the detection of G. duodenalis coproantigens in stool samples by a sensitivity of 97% and a specificity of 92.72%. Moreover, G. duodenalis cyst was detected in only seven water samples by ordinary microscopy; while sandwich ELISA revealed nineteen positive results. IgG pAb (1/200 µg/ml) protected mice from giardiasis; which was evident from the reduction in cysts and trophozoites numbers. We recommended the use of sandwich ELISA to monitor water quality, investigate environmental contamination and diagnosis in patients' stools. The pAbs can be prepared in large amount and used in field diagnosis and protection. This will help in the early diagnosis of G. duodenalis in water, which in turn can control outbreaks in rural areas.