A Prognostic Activity of Glutaredoxin 1 Protein (Grx1) in Colon Cancer.

Glutaredoxin 1 (Grx1) is an essential enzyme that regulates redox signal transduction and repairs protein oxidation by reversing S-glutathionylation, an oxidative modification of protein cysteine residues. Grx1 removes glutathione from proteins to restore their reduced state (protein-SH) and regulate protein-SSG levels in redox signaling networks. Thus, it can exert an influence on the development of cancer. To further investigate this problem, we performed an analysis of Grx1 expression in colon adenocarcinoma samples from the Polish population of patients with primary colon adenocarcinoma (stages I and II of colon cancer) and those with regional lymph node metastasis (stage III of colon cancer). Our study revealed a significant correlation between the expression of Grx1 protein through immunohistochemical analysis and various clinical characteristics of patients, such as histological grade, depth of invasion, angioinvasion, staging, regional lymph node invasion, and PCNA expression. It was found that almost 88% of patients with stage I had high levels of Grx1 expression, while only 1% of patients with stage III exhibited high levels of Grx1 protein expression. Furthermore, the study discovered that high levels of Grx1 expression were present in samples of colon mucosa without any pathological changes. These results were supported by in vitro analysis conducted on colorectal cancer cell lines that corresponded to stages I, II, and III of colorectal cancer, using qRT-PCR and Western blot.

Glutaredoxin 2 Protein (Grx2) as an Independent Prognostic Factor Associated with the Survival of Colon Adenocarcinoma Patients.

Glutaredoxin 2 (Grx2; Glrx2) is a glutathione-dependent oxidoreductase located in mitochondria, which is central to the regulation of glutathione homeostasis and mitochondrial redox, and plays a crucial role in highly metabolic tissues. In response to mitochondrial redox signals and oxidative stress, Grx2 can catalyze the oxidation and S-glutathionylation of membrane-bound thiol proteins in mitochondria. Therefore, it can have a significant impact on cancer development. To investigate this further, we performed an immunohistochemical analysis of Grx2 protein expression in colon adenocarcinoma samples collected from patients with primary colon adenocarcinoma (stage I and II) and patients with metastasis to regional lymph nodes (stage III). The results of our study revealed a significant relationship between the immunohistochemical expression of Grx2 and tumor histological grade, depth of invasion, regional lymph node involvement, angioinvasion, staging, and PCNA immunohistochemical expression. It was found that 87% of patients with stage I had high levels of Grx2 expression. In contrast, only 33% of patients with stage II and 1% of patients with stage III had high levels of Grx2 expression. Moreover, the multivariate analysis revealed that the immunohistochemical expression of Grx2 protein apart from the grade of tumor differentiation was an independent prognostic factors for the survival of patients with colon adenocarcinoma. Studies analyzing Grx2 levels in patients' blood confirmed that the highest levels of serum Grx2 protein was also found in stage I patients, which was reflected in the survival curves. A higher level of Grx2 in the serum has been associated with a more favorable outcome. These results were supported by in vitro analysis conducted on colorectal cancer cell lines that corresponded to stages I, II, and III of colorectal cancer, using qRT-PCR and Western Blot.

Glutathione Reductase Expression and Its Prognostic Significance in Colon Cancer.

Maintaining a balanced redox state within cells is crucial for the sustenance of life. The process involves continuous cytosolic disulfide reduction reactions to restore oxidized proteins to their reduced thiol forms. There are two main cellular antioxidant pathways-the thioredoxin (Trx) and glutathione (GSH)/glutaredoxin (Grx) systems. In the GSH/Grx system, glutathione reductase (GR; GSR) catalyses the reduction of GSH disulfide (GSSG) to its sulfhydryl form (GSH), which can then further reduce oxidized Grxs. GR is an essential enzyme that helps in maintaining the supply of reduced glutathione-GSH, which is a significant reducing thiol found in most cells and known for its antioxidant properties. Therefore, it can have a significant impact on cancer development. To investigate this further, we performed an immunohistochemical analysis of GR protein expression in colon adenocarcinoma samples collected from patients with primary colon adenocarcinoma (stage I and II) and patients with metastasis to regional lymph nodes (stage III). The results of our study revealed a significant relationship between the immunohistochemical expression of GR and tumour histological grade, depth of invasion, regional lymph node involvement, staging, and PCNA immunohistochemical expression. It was found that 95% of patients with stage I had low levels of GR expression, whereas 89% of patients with stage III had high levels of immunohistochemical expression. A high level of expression was also detected in the patients with stage II of the disease, where almost 63% were characterized by a high expression of GR. The Western blot method revealed that the highest level of expression was found in the LS 174T cell line, which corresponds to stage II. The results of our study indicate that the immunohistochemical expression of GR may act as an independent prognostic factor associated with colon adenocarcinoma patients' prognosis.

Immunohistochemical Expression of Glutathione Peroxidase-2 (Gpx-2) and Its Clinical Relevance in Colon Adenocarcinoma Patients.

Glutathione peroxidase 2 (Gpx-2) is a selenoenzyme with antioxidant capabilities that may play a role in cancer development. Hence, we investigated the immunohistochemical expression of Gpx-2 protein in colon adenocarcinoma samples derived from patients with colon adenocarcinoma who did not receive any form of treatment prior to the surgical procedure. The associations between the immunohistochemical expression of Gpx-2 and clinical parameters were analysed using the Chi2 test and Fisher's exact test. A Kaplan-Meier analysis and the log-rank test were used to verify the relationship between the intensity of Gpx-2 expression and the 5-year survival rate of patients. In total, 101 (80.80%) samples had strong Gpx-2 protein expression and 24 (19.20%) samples were characterized with low expression. The high expression of Gpx-2 was correlated with the histological grade of the tumour (p < 0.001), PCNA immunohistochemical expression (p < 0.001), depth of invasion (p = 0.001) and angioinvasion (p < 0.001). We can conclude that high expression of Gpx-2 is correlated with reduced survival of colon adenocarcinoma patients (log-rank, p < 0.001).

The Clinical Application of Immunohistochemical Expression of Notch4 Protein in Patients with Colon Adenocarcinoma.

The Notch signalling pathway is one of the most conserved and well-characterised pathways involved in cell fate decisions and the development of many diseases, including cancer. Among them, it is worth noting the Notch4 receptor and its clinical application, which may have prognostic value in patients with colon adenocarcinoma. The study was performed on 129 colon adenocarcinomas. Immunohistochemical and fluorescence expression of Notch4 was performed using the Notch4 antibody. The associations between the IHC expression of Notch4 and clinical parameters were analysed using the Chi2 test or Chi2Yatesa test. The Kaplan-Meier analysis and the log-rank test were used to verify the relationship between the intensity of Notch4 expression and the 5-year survival rate of patients. Intracellular localisation of Notch4 was detected by the use of the immunogold labelling method and TEM. 101 (78.29%) samples had strong Notch4 protein expression, and 28 (21.71%) samples were characterised by low expression. The high expression of Notch4 was clearly correlated with the histological grade of the tumour (p < 0.001), PCNA immunohistochemical expression (p < 0.001), depth of invasion (p < 0.001) and angioinvasion (p < 0.001). We can conclude that high expression of Notch4 is correlated with poor prognosis of colon adenocarcinoma patients (log-rank, p < 0.001).

Liver Oxidative Status, Serum Lipids Levels after Bariatric Surgery and High-Fat, High-Sugar Diet in Animal Model of Induced Obesity.

Nutritional status is a major determinant of hepatocyte injuries associated with changed metabolism and oxidative stress. This study aimed to determine the relations between oxidative stress, bariatric surgery, and a high-fat/high-sugar (HFS) diet in a diet-induced obesity rat model. Male rats were maintained on a control diet (CD) or high-fat/high-sugar diet (HFS) inducing obesity. After 8 weeks, the animals underwent SHAM (n = 14) or DJOS (n = 14) surgery and the diet was either changed or unchanged. Eight weeks after the surgeries, the activity of superoxide dismutase isoforms (total SOD, MnSOD, and CuZnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and lutathione S-transferase, as well as the thiol groups (-SH) concentration, total antioxidant capacity (TAC), total oxidative stress (TOS) levels, and malondialdehyde (MDA) concentration liver tissue were assessed. The total cholesterol, triglycerides (TG), and high-density lipoprotein (HDL) concentrations were measured in the serum. The total SOD and GPX activities were higher in the SHAM-operated rats than in the DJOS-operated rats. The MnSOD activity was higher in the HFS/HFS than the CD/CD groups. Higher CuZnSOD, GST, GR activities, -SH, and MDA concentrations in the liver, and the triglyceride and cholesterol concentrations in the serum were observed in the SHAM-operated rats than in the DJOS-operated rats. The CAT activity was significantly higher in the HFS-fed rats. Lower TAC and higher TOS values were observed in the SHAM-operated rats. Unhealthy habits after bariatric surgery may be responsible for treatment failure and establishing an obesity condition with increased oxidative stress.

A possible link between the Epstein-Barr virus infection and autoimmune thyroid disorders.

The Epstein-Barr virus (EBV), also known as human herpesvirus 4, is a member of the Herpesviridae virus family. EBV infection can cause infectious mononucleosis (IM) in the lytic phase of EBV's life cycle. Past EBV infection is associated with lymphomas, and may also result in certain allergic and autoimmune diseases. Although potential mechanisms of autoimmune diseases have not been clearly elucidated, both genetic and environmental factors, such as infectious agents, are considered to be responsible for their development. In addition, EBV modifies the host immune response. The worldwide prevalence of autoimmune diseases shows how common this pathogen is. Normally, the virus stays in the body and remains dormant throughout life. However, this is not always the case, and a serious EBV-related illness may develop later in life. This explains the chronic course of autoimmune diseases that is often accompanied by exacerbations of symptoms. Based on the present studies, EBV infection can cause autoimmune diseases, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), rheumatoid arthritis (RA), Sjögren's syndrome, and autoimmune hepatitis. The EBV has also been reported in patients with autoimmune thyroid disorders. Although EBV is not the only agent responsible for the development of autoimmune thyroid diseases, it can be considered a contributory factor.

Notch signalling pathway as an oncogenic factor involved in cancer development.

Notch signalling is an evolutionarily conserved signalling pathway, which plays a significant role in a wide array of cellular processes including proliferation, differentiation, and apoptosis. Nevertheless, it must be noted that Notch is a binary cell fate determinant, and its overexpression has been described as oncogenic in a broad range of human malignancies. This finding led to interest in therapeutically targeting this pathway especially by the use of GSIs, which block the cleavage of Notch at the cell membrane and inhibit release of the transcriptionally active NotchIC subunit. Preclinical cancer models have clearly demonstrated that GSIs suppress the growth of such malignancies as pancreatic, breast, and lung cancer; however, GSI treatment in vivo is associated with side effects, especially those within the gastrointestinal tract. Although intensive studies are associated with the role of γ-secretase in pathological states, it should be pointed out that this complex impacts on proteolytic cleavages of around 55 membrane proteins. Therefore, it is clear that GSIs are highly non-specific and additional drugs must be designed, which will more specifically target components of the Notch signalling.

Angiogenesis in primary hyperparathyroidism.

Angiogenesis can be described as a formation of new vessels from the existing microvasculature and is a process of great importance to the tumor development. Parathyroid tissue can trigger spontaneous induction of angiogenesis in vitro and in vivo models in a vascular endothelial growth factor (VEGF)-dependent manner. Autotransplantated parathyroid tissue after thyroidectomy is able to form new vasculature and produce parathormone, maintaining calcium homeostasis. A great amount of factors contributes to the process of new vessel formation in primary hyperparathyroidism, such as VEGF, transforming growth factor ß, and angiopoietins. Studies demonstrated that markers for angiogenesis can be useful in distinguishing between parathyroid hyperplasia and neoplasia, due to the increased angiogenesis in parathyroid proliferative lesions compared with parathyroid adenomas. These factors include, inter alia, VEGF, VEGFR2, CD105, and fibroblast growth factor-2. Although these differences appear promising in the differential diagnosis, there is an overlap between benign and malignant parathyroid lesions and there is no definite cutoff value. Loss of heterozygosity and comparative genomic hybridization studies revealed chromosomal regions frequently altered in parathyroid tumorigenesis at 9p21, 1p21-22, 1p35-36, and 11q13. Therefore, immunohistochemistry and genetic testing should be an additional diagnostic marker in combination with the traditional criteria. A better understanding of angiogenesis in primary hyperparathyroidism could result in more precise assessment of diagnosis and more effective treatment, especially in those cases, in which the commonly used parameters are insufficient.

Potential use of histone deacetylase inhibitors in cancer therapy.

Epigenetics is a branch of science that focuses on mechanisms related to control and modification of expression of genetic material without any changes to its sequences. Such mechanisms include post-translational modifications of histones. It is widely known that carcinogenesis is related to hypoacetylation of genes that influence apoptosis, the cell cycle, cell signaling, the immunologic response, angiogenesis and occurrence of metastasis. Currently conducted research focuses on several strategies related to epigenetic therapy. One such strategy is based on the use of histone deacetylase inhibitors. This paper presents mechanisms through which these compounds work and a summary of their characteristics. It also includes a review of clinical tests related to histone deacetylase inhibitors, as well as their relationship with other chemotherapeutic methods. A better understanding of the involved mechanisms will provide a rational basis to improve the therapeutic outcome of available antitumor agents.

The role of Snail1 transcription factor in colorectal cancer progression and metastasis.

Snail1 is a zinc-finger transcription factor, which plays a role in colorectal cancer development by silencing E-cadherin expression and inducing epithelialmesenchymal transition (EMT). During EMT tumour cells acquire a mesenchymal phenotype that is responsible for their invasive activities. Consequently, Snail1 expression in colorectal cancer is usually associated with progression and metastasis. Some studies revealed that about 77% of colon cancer samples display Snail1 immunoreactivity both in activated fibroblasts and in carcinoma cells that have undergone EMT. Therefore, expression of this factor in the stroma may indicate how many cells possess the abilities to escape from the primary tumour mass, invade the basal lamina and colonise distant target organs. Blocking snail proteins activity has the potential to avert cancer cell metastasis by interfering with such cellular processes as remodelling of the actin cytoskeleton, migration and invasion, which are clearly associated with the aggressive phenotype of the disease. Moreover, the link between factors from the snail family and cancer stem cells suggests that inhibitory agents may also prove their potency as inhibitors of cancer recurrence.

Role of Notch signaling pathway in gastric cancer pathogenesis.

Notch signaling pathway is activated dynamically during evolution playing significant role in cell fate determination and differentiation. It has been known that alterations of this pathway may lead to human malignancies, including gastric cancer. Despite a decline in the overall incidence, this disease still remains an important global health problem. Therefore, a better understanding of the molecular alterations underlying gastric cancer may contribute to the development of rationally designed molecular targeted therapies. It has been reported that Notch1 receptor could become a prognostic marker of gastric cancer and novel target for gastric cancer therapy. Among the novel and targeted approaches for the treatment of gastric cancer is also the process of Notch receptors regulation by specific microRNA. γ-secretase inhibitors are also taken into consideration.

Immunohistochemical Expression of Upregulated Gene 4 Protein Expression (URG4/URGCP) and Its Association with 5-Year Survival in Patients with Colon Adenocarcinoma.

(1) Background: Colorectal cancer (CRC) is the third most common cancer in terms of incidence and mortality. Approximately 90% of all colorectal cancer cases are adenocarcinomas, originating from epithelial cells of the colorectal mucosa. Upregulated gene 4 (URG4) is an oncogene involved in cancer development. The aim of the study was to assess the immunohistochemical expression of URG4 protein expression in Polish patients with colon adenocarcinoma who were not treated with any therapy before radical surgery. (2) Methods: The study used colon tissue samples taken from people with a confirmed diagnosis of colorectal adenocarcinoma after a thorough histopathological examination. The associations between the immunohistochemical expression of URG4 and clinical parameters were analyzed by the Chi2 test or Chi2Yatesa test. The study conducted an analysis of the correlation between the expression of URG4 and the five-year survival rate of patients through the application of the Kaplan-Meier analysis and the log-rank statistical test. The intracellular localization of URG4 was identified through the utilization of transmission electron microscopy (TEM) methodology. (3) Results: In univariate Cox regression analyses, immuno-histochemical expression of URG4, grade of histological differentiation, depth of invasion, angioinvasion, PCNA expression, stage of disease and lymph node involvement were found to be significant prognostic factors. Within our patient cohort, it was observed that the degree of tumour differentiation and URG4 expression were found to be distinct prognostic factors in regard to the 5-year survival rates of those with colon adenocarcinoma. (4) Conclusions: High immunohistochemical expression of URG4 correlates with poor prognosis in patients with colon adenocarcinoma.

The Prognostic Significance of Apoptotic Protease Activating Factor (Apaf-1) Protein Expression in Colon Adenocarcinoma Tissue-Preliminary Report.

BACKGROUND: The Apoptotic protease activating factor 1 (Apaf-1) protein, as one of the factors involved in the activation of the mitochondrial apoptotic pathway, plays an important role in cancer biology. Apaf-1 expression in tumour cells has been shown to be downregulated, with significant implications for tumour progression. Hence, we investigated the expression of Apaf-1 protein in the Polish population of patients with colon adenocarcinoma without any therapy prior to radical surgery. Moreover, we assessed the relation between Apaf-1 protein expression and the clinicopathological factors. The prognostic activity of this protein was analyzed in relation to 5-year survival of patients. In order to show the localization of Apaf-1 protein at the cellular level, the immunogold labelling method was used. METHODS: The study was conducted using the colon tissue material from patients with histopathologically confirmed colon adenocarcinoma. Immunohistochemical expression of Apaf-1 protein was performed using Apaf-1 antibody at dilution 1:600. The associations between the immunohistochemistry (IHC) expression of Apaf-1 and clinical parameters were analyzed using the Chi2 test and Chi2Yatesa test. Kaplan-Meier analysis and the log-rank test were used to verify the relationship between the intensity of Apaf-1 expression and 5-year survival rate of patients. The results were considered statistically significant when p < 0.05. RESULTS: Apaf-1 expression was evaluated by immunohistochemical staining in whole tissue sections. Thirty-nine (33.23%) samples had strong Apaf-1 protein expression and 82 (67.77%) samples were characterized by low expression. The high expression of Apaf-1 was clearly correlated with the histological grade of the tumour (p = 0.001), proliferating cell nuclear antigen (PCNA) immunohistochemical expression (p = 0.005), age (p = 0.015), depth of invasion (p < 0.001) and angioinvasion (p < 0.001). The 5-year survival rate was significantly higher in the group of patients with high expression of this protein (log-rank, p < 0.001). CONCLUSIONS: We can conclude that Apaf-1 expression is positively correlated with reduced survival of colon adenocarcinoma patients.

Immunohistochemical Expression of Glutathione Peroxidase 1 (Gpx-1) as an Independent Prognostic Factor in Colon Adenocarcinoma Patients.

Several studies revealed that expression levels of glutathione peroxidase 1 (Gpx-1) can be associated with cancer development, mainly through its role in hydroperoxide scavenging by regulating intracellular reactive oxygen species (ROS) levels. Therefore, our aim was to investigate the expression of Gpx-1 protein in a population of Polish patients with colon adenocarcinoma in the absence of any therapy prior to radical surgery. The study was carried out using colon tissue from patients with adenocarcinoma of the colon confirmed by histopathological examination. Gpx-1 antibody was used to determine the immunohistochemical expression of Gpx-1. The Chi2test or Chi2Yatesa test were used to analyse the associations between the immunohistochemical expression of Gpx-1 and clinical parameters. The relationship between Gpx-1 expression, and 5-year patient survival was examined using Kaplan-Meier analysis and the log-rank test. Intracellular localisation of Gpx-1 was detected by the use of transmission electron microscopy (TEM). Western blot analysis was used for the evaluation of Gpx-1 protein expression levels in cancer cell lines in vitro. Immunohistochemical study revealed that the high expression of Gpx-1 was associated with the tumour's histological grade, proliferating cell nuclear antigen (PCNA) immunohistochemical expression, depth of invasion, and angioinvasion (all p < 0.001) (4). The high immunohistochemical expression of Gpx-1 is correlated with poor prognosis of colon adenocarcinoma patients.

Spatiotemporal variation of leaf epidermal cell growth: a quantitative analysis of Arabidopsis thaliana wild-type and triple cyclinD3 mutant plants.

BACKGROUND AND AIMS: The epidermis of an expanding dicot leaf is a mosaic of cells differing in identity, size and differentiation stage. Here hypotheses are tested that in such a cell mosaic growth is heterogeneous and changes with time, and that this heterogeneity is not dependent on the cell cycle regulation per se. METHODS: Shape, size and growth of individual cells were followed with the aid of sequential replicas in expanding leaves of wild-type Arabidopsis thaliana and triple cyclinD3 mutant plants, and combined with ploidy estimation using epi-fluorescence microscopy. KEY RESULTS: Relative growth rates in area of individual epidermal cells or small cell groups differ several fold from those of adjacent cells, and change in time. This spatial and temporal variation is not related to the size of either the cell or the nucleus. Shape changes and growth within an individual cell are also heterogeneous: anticlinal wall waviness appears at different times in different wall portions; portions of the cell periphery in contact with different neighbours grow with different rates. This variation is not related to cell growth anisotropy. The heterogeneity is typical for both the wild type and cycD3. CONCLUSIONS: Growth of leaf epidermis exhibits spatiotemporal variability.

The human aural myiasis caused by Lucilia sericata.

Myiasis is a rare, worldwide, human disease with seasonal variation, caused by developing larvae of a variety of fly species. It can be dangerous when infestations penetrate into the brain. In the available literature, we have found only a few papers concerning ear myiasis caused by Lucilia sericata. Here, we report 2 cases of aural myiasis. Early intervention (surgical removal, occlusion) in these cases should prevent complications. Larvae, for further examination, should be killed by immersion in very hot water, then preserved in an ethanol.

From Phenology and Habitat Preferences to Climate Change: Importance of Citizen Science in Studying Insect Ecology in the Continental Scale with American Red Flat Bark Beetle, Cucujus clavipes, as a Model Species.

The American red flat bark beetle, Cucujus clavipes, is a wide distributed saproxylic species divided into two subspecies: ssp. clavipes restricted to eastern regions of North America and ssp. puniceus occurring only in western regions of this continent. Unique morphological features, including body shape and body coloration, make this species easy to recognize even for amateurs. Surprisingly, except some studies focused on physiological adaptations of the species, the ecology of C. clavipes was almost unstudied. Based on over 500 records collected by citizen scientists and deposited in the iNaturalist data base, we studied phenological activity of adult beetles, habitat preferences and impact of future climate change for both subspecies separately. The results clearly show that spp. clavipes and ssp. puniceus can be characterized by differences in phenology and macrohabitat preferences, and their ranges do not overlap at any point. Spp. clavipes is found as more opportunistic taxon occurring in different forests as well as in urban and agricultural areas with tree vegetation always in elevations below 500 m, while elevational distribution of ssp. puniceus covers areas up to 2300 m, and the beetle was observed mainly in forested areas. Moreover, we expect that climate warming will have negative influence on both subspecies with the possible loss of proper niches at level even up to 47-70% of their actual ranges during next few decades. As the species is actually recognized as unthreatened and always co-occurs with many other species, we suggest, because of its expected future habitat loss, to pay more attention to conservationists for possible negative changes in saproxylic insects and/or forest fauna in North America. In addition, as our results clearly show that both subspecies of C. clavipes differ ecologically, which strongly supports earlier significant morphological and physiological differences noted between them, we suggest that their taxonomical status should be verified by molecular data, because very probably they represent separate species.

New Species of Soldier Fly-Sargus bipunctatus (Scopoli, 1763) (Diptera: Stratiomyidae), Recorded from a Human Corpse in Europe-A Case Report.

The only European Stratiomyidae species known for feeding on human corpses was the black soldier fly Hermetia illucens (Linnaeus, 1758). Analysis of fauna found on a human corpse, discovered in central Poland, revealed the presence of feeding larvae of another species from this family: the twin-spot centurion fly Sargus bipunctatus (Scopoli, 1763). The investigated corpse was in a stage of advanced decomposition. The larvae were mainly observed in the adipocere formed on the back and lower limbs of the corpse, and in the mixture of litter and lumps of adipocere located under the corpse. Adult specimens and larvae were identified based on morphological characters, and final identification was confirmed using DNA barcoding. Implementing a combination of morphological and molecular methods provided a reliable way for distinguishing the larvae of S. bipunctatus and H. illucens. The potential of S. bipunctatus for practical applications in forensic entomology is currently difficult to assess. Wide and reliable use of S. bipunctatus in the practice of forensic entomology requires further studies of the bionomy of this fly.

First records of the Palaestes abruptus Sharp, 1899 and P. nicaraguae Sharp, 1899 (Coleoptera: Cucujidae) from South America, with a checklist of flat bark beetles from the continent.

BACKGROUND: The flat bark beetles (Coleoptera: Cucujidae) is a small insect family with only about 70 species. Most of the species are distributed in Holarctic, Oriental and/or Australasian realms, while in South America, only six species have been recorded, including a single one known from Peru. NEW INFORMATION: Two cucujid beetle species, Palaestes abruptus Sharp, 1899 and P. nicaraguae Sharp, 1899, are recorded from South America for the first time. The species are recorded from the Pasco (P. abruptus) and Cusco and Junín (P. nicaraguae) Regions of Peru, based, in part, on data collected through the iNaturalist citizen science database. Habitats of both species are presented in photographs for the first time. A country-level checklist to Cucujidae species currently known from South America is provided.