Sulforaphane rewires central metabolism to support antioxidant response and achieve glucose homeostasis.

Cruciferous-rich diets, particularly broccoli, have been associated with reduced risk of developing cancers of various sites, cardiovascular disease and type-2 diabetes. Sulforaphane (SF), a sulfur-containing broccoli-derived metabolite, has been identified as the major bioactive compound mediating these health benefits. Sulforaphane is a potent dietary activator of the transcription factor Nuclear factor erythroid-like 2 (NRF2), the master regulator of antioxidant cell capacity responsible for inducing cytoprotective genes, but its role in glucose homeostasis remains unclear. In this study, we set to test the hypothesis that SF regulates glucose metabolism and ameliorates glucose overload and its resulting oxidative stress by inducing NRF2 in human hepatoma HepG2 cells. HepG2 cells were exposed to varying glucose concentrations: basal (5.5 mM) and high glucose (25 mM), in the presence of physiological concentrations of SF (10 µM). SF upregulated the expression of glutathione (GSH) biosynthetic genes and significantly increased levels of reduced GSH. Labelled glucose and glutamine experiments to measure metabolic fluxes identified that SF increased intracellular utilisation of glycine and glutamate by redirecting the latter away from the TCA cycle and increased the import of cysteine from the media, likely to support glutathione synthesis. Furthermore, SF altered pathways generating NADPH, the necessary cofactor for oxidoreductase reactions, namely pentose phosphate pathway and 1C-metabolism, leading to the redirection of glucose away from glycolysis and towards PPP and of methionine towards methylation substrates. Finally, transcriptomic and targeted metabolomics LC-MS analysis of NRF2-KD HepG2 cells generated using CRISPR-Cas9 genome editing revealed that the above metabolic effects are mediated through NRF2. These results suggest that the antioxidant properties of cruciferous diets are intricately connected to their metabolic benefits.

A Chemical Chaperone Restores Connexin 26 Mutant Activity.

Mutations in connexin 26 (Cx26) cause hearing disorders of a varying degree. Herein, to identify compounds capable of restoring the function of mutated Cx26, a novel miniaturized microarray-based screening system was developed to perform an optical assay of Cx26 functionality. These molecules were identified through a viability assay using HeLa cells expressing wild-type (WT) Cx26, which exhibited sensitivity toward the HSP90 inhibitor radicicol in the submicromolar concentration range. Open Cx26 hemichannels are assumed to mediate the passage of molecules up to 1000 Da in size. Thus, by releasing radicicol, WT Cx26 active hemichannels in HeLa cells contribute to a higher survival rate and lower cell viability when Cx26 is mutated. HeLa cells expressing Cx26 mutations exhibited reduced viability in the presence of radicicol, such as the mutants F161S or R184P. Next, molecules exhibiting chemical chaperoning activity, suspected of restoring channel function, were assessed regarding whether they induced superior sensitivity toward radicicol and increased HeLa cell viability. Through a viability assay and microarray-based flux assay that uses Lucifer yellow in HeLa cells, compounds 3 and 8 were identified to restore mutant functionality. Furthermore, thermophoresis experiments revealed that only 3 (VRT-534) exhibited dose-responsive binding to recombinant WT Cx26 and mutant Cx26K188N with half maximal effective concentration values of 19 and ∼5 µM, respectively. The findings of this study reveal that repurposing compounds already being used to treat other diseases, such as cystic fibrosis, in combination with functional bioassays and binding tests can help identify novel potential candidates that can be used to treat hearing disorders.

PGM3 inhibition shows cooperative effects with erastin inducing pancreatic cancer cell death via activation of the unfolded protein response.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with a poor patient prognosis. Remarkably, PDAC is one of the most aggressive and deadly tumor types and is notorious for its resistance to all types of treatment. PDAC resistance is frequently associated with a wide metabolic rewiring and in particular of the glycolytic branch named Hexosamine Biosynthetic Pathway (HBP). Methods: Transcriptional and bioinformatics analysis were performed to obtain information about the effect of the HBP inhibition in two cell models of PDAC. Cell count, western blot, HPLC and metabolomics analyses were used to determine the impact of the combined treatment between an HBP's Phosphoglucomutase 3 (PGM3) enzyme inhibitor, named FR054, and erastin (ERA), a recognized ferroptosis inducer, on PDAC cell growth and survival. Results: Here we show that the combined treatment applied to different PDAC cell lines induces a significant decrease in cell proliferation and a concurrent enhancement of cell death. Furthermore, we show that this combined treatment induces Unfolded Protein Response (UPR), NFE2 Like BZIP Transcription Factor 2 (NRF2) activation, a change in cellular redox state, a greater sensitivity to oxidative stress, a major dependence on glutamine metabolism, and finally ferroptosis cell death. Conclusion: Our study discloses that HBP inhibition enhances, via UPR activation, the ERA effect and therefore might be a novel anticancer mechanism to be exploited as PDAC therapy.

Heavy Youngsters-Habitat and Climate Factors Lead to a Significant Increase in Body Weight of Wild Boar Females.

As one of the most abundant game species in Europe, European wild boar (Sus scrofa) populations prove highly adaptable to cultivated landscapes. The ongoing process of climate change and the high agricultural yields seem to further optimize the living conditions for this species. In long-term reproduction monitoring, we collected data on the body weight of wild boar females. Over an 18-year period, the body weight of wild boar females increased continuously, then stopped and decreased. It was possible to detect differences between the body weights of animals from forest and agricultural areas. For these areas, differences in body weight development also led to a significant distinction in the onset of puberty. We conclude that, even in a highly cultivated landscape, forested areas provide habitat characteristics that may strongly influence reproduction. Second, with dominant agricultural areas in Germany, wild boar reproduction has been favored in recent decades.

More than 30 Years of POSSUM: Are Scoring Systems Still Relevant Today for Colorectal Surgery?

BACKGROUND: The Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) weights the patient's individual health status and the extent of the surgical procedure to estimate the probability of postoperative complications and death of general surgery patients. The variations Portsmouth-POSSUM (P-POSSUM) and colorectal POSSUM (CR-POSSUM) were developed for estimating mortality in patients with low perioperative risk and for patients with colorectal carcinoma, respectively. The aim of the present study was to evaluate the significance of POSSUM, P-POSSUM, and CR-POSSUM in two independent colorectal cancer cohorts undergoing surgery, with an emphasis on laparoscopic procedures. METHODS: For each patient, an individual physiological score (PS) and operative severity score (OS) was attributed to calculate the predicted morbidity and mortality, respectively. Logistic regression analysis was used to evaluate the possible correlation between the subscores and the probability of postoperative complications and mortality. RESULTS: The POSSUM equation significantly overpredicted postoperative morbidity, and all three scoring systems considerably overpredicted in-hospital mortality. However, the POSSUM score identified patients at risk of anastomotic leakage, sepsis, and the need for reoperation. Logistic regression analysis demonstrated a strong correlation between the subscores and the probability of postoperative complications and mortality, respectively. CONCLUSION: Our results suggest that the three scoring systems are too imprecise for the estimation of perioperative complications and mortality of patients undergoing colorectal surgery in the present day. Since the subscores proved valid, a revision of the scoring systems could increase their reliability in the clinical setting.

Habitat selection of black grouse in an isolated population in northern Germany-the importance of mixing dry and wet habitats.

Wildlife habitats in general must provide foraging, hiding and resting places as well as sites for reproduction. Little is known about habitat selection of black grouse in the lowlands of Central Europe. We investigated habitat selection of seven radio tagged birds in an open heath and grassland area surrounded by dense pine forests in the northern German Lüneburg Heath Nature Reserve. This site carries one of the last remaining populations in the Central European lowlands. Using resource selection functions based on presence/background data, we estimated the probability of black grouse occurrence by availability of, or distance to habitat types as well as vegetation diversity indices. Black grouse preferred undisturbed and heterogeneous habitats far from dense forests with wide sand heaths, natural grasslands and intermixed bogs, diverse vegetation and food sources, low density of (loose) shrub formations and solitary trees. Wetlands were extremely important in a landscape that is dominated by dry heaths and grasslands. About 4% (9 km2) of the nature reserve was a suitable habitat for black grouse, mostly due to lack of open areas due to the amount of dense forest, and because smaller, open heaths are only partly suitable. We suggest that to improve habitat quality and quantity for the grouse, habitat patch size and connectivity must be increased, along with a mosaic of heterogeneous landscape structures in these habitat islands. Our results may be used to inform and improve black grouse habitat management in the region and elsewhere.

ISG15 deficiency features a complex cellular phenotype that responds to treatment with itaconate and derivatives.

BACKGROUND: Congenital ISG15 deficiency is a rare autoinflammatory disorder that is driven by chronically elevated systemic interferon levels and predominantly affects central nervous system and skin. METHODS AND RESULTS: We have developed induced pluripotent stem cell-derived macrophages and endothelial cells as a model to study the cellular phenotype of ISG15 deficiency and identify novel treatments. ISG15-/- macrophages exhibited the expected hyperinflammatory responses, but normal phagocytic function. In addition, they displayed a multifaceted pathological phenotype featuring increased apoptosis/pyroptosis, oxidative stress, glycolysis, and acylcarnitine levels, but decreased glutamine uptake, BCAT1 expression, branched chain amino acid catabolism, oxidative phosphorylation, ß-oxidation, and NAD(P)H-dependent oxidoreductase activity. Furthermore, expression of genes involved in mitochondrial biogenesis and respiratory chain complexes II-V was diminished in ISG15-/- cells. Defective mitochondrial respiration was restored by transduction with wild-type ISG15, but only partially by a conjugation-deficient variant, suggesting that some ISG15 functions in mitochondrial respiration require ISGylation to cellular targets. Treatment with itaconate, dimethyl-itaconate, 4-octyl-itaconate, and the JAK1/2 inhibitor ruxolitinib ameliorated increased inflammation, propensity for cell death, and oxidative stress. Furthermore, the treatments greatly improved mitochondria-related gene expression, BCAT1 levels, redox balance, and intracellular and extracellular ATP levels. However, efficacy differed among the compounds according to read-out and cell type, suggesting that their effects on cellular targets are not identical. Indeed, only itaconates increased expression of anti-oxidant genes NFE2L2, HMOX1, and GPX7, and dimethyl-itaconate improved redox balance the most. Even though itaconate treatments normalized the elevated expression of interferon-stimulated genes, ISG15-/- macrophages maintained their reduced susceptibility to influenza virus infection. CONCLUSIONS: These findings expand the cellular phenotype of human ISG15 deficiency and reveal the importance of ISG15 for regulating oxidative stress, branched chain amino acid metabolism, and mitochondrial function in humans. The results validate ruxolitinib as treatment for ISG15 deficiency and suggest itaconate-based medications as additional therapeutics for this rare disorder.

Construction and Characterization of T7 Bacteriophages Harboring Apidaecin-Derived Sequences.

The global spread of multi- and pan-resistant bacteria has triggered research to identify novel strategies to fight these pathogens, such as antimicrobial peptides and, more recently, bacteriophages. In a proof-of-concept study, we have genetically modified lytic T7Select phages targeting Escherichia coli Rosetta by integrating DNA sequences derived from the proline-rich antimicrobial peptide, apidaecin. This allowed testing of our hypothesis that apidaecins and bacteriophages can synergistically act on phage-sensitive and phage-resistant E. coli cells and overcome the excessive cost of peptide drugs by using infected cells to express apidaecins before cell lysis. Indeed, the addition of the highly active synthetic apidaecin analogs, Api802 and Api806, to T7Select phage-infected E. coli Rosetta cultures prevented or delayed the growth of potentially phage-resistant E. coli Rosetta strains. However, high concentrations of Api802 also reduced the T7Select phage fitness. Additionally, plasmids encoding Api802, Api806, and Api810 sequences transformed into E. coli Rosetta allowed the production of satisfactory peptide quantities. When these sequences were integrated into the T7Select phage genome carrying an N-terminal green fluorescent protein (GFP-) tag to monitor the expression in infected E. coli Rosetta cells, the GFP-apidaecin analogs were produced in reasonable quantities. However, when Api802, Api806 and Api810 sequences were integrated into the T7Select phage genome, expression was below detection limits and an effect on the growth of potentially phage-resistant E. coli Rosetta strains was not observed for Api802 and Api806. In conclusion, we were able to show that apidaecins can be integrated into the T7Select phage genome to induce their expression in host cells, but further research is required to optimize the engineered T7Select phages for higher expression levels of apidaecins to achieve the expected synergistic effects that were visible when the T7Select phages and synthetic Api802 and Api806 were added to E. coli Rosetta cultures.

Antimicrobial Activity and 70S Ribosome Binding of Apidaecin-Derived Api805 with Increased Bacterial Uptake Rate.

In view of the global spread of multiresistant bacteria and the occurrence of panresistant bacteria, there is an urgent need for antimicrobials with novel modes of action. A promising class is antimicrobial peptides (AMPs), including them proline-rich AMPs (PrAMPs), which target the 70S ribosome to inhibit protein translation. Here, we present a new designer peptide, Api805, combining the N- and C-terminal sequences of PrAMPs Api137 and drosocin, respectively. Api805 was similarly active against two Escherichia coli B strains but was inactive against E. coli K12 strain BW25113. These different activities could not be explained by the dissociation constants measured for 70S ribosome preparations from E. coli K12 and B strains. Mutations in the SbmA transporter that PrAMPs use to pass the inner membrane or proteolytic degradation of Api805 by lysate proteases could not explain this either. Interestingly, Api805 seems not to bind to the known binding sites of PrAMPs at the 70S ribosome and inhibited in vitro protein translation, independent of release factors, most likely using a "multimodal effect". Interestingly, Api805 entered the E. coli B strain Rosetta faster and at larger quantities than the E. coli K-12 strain BW25113, which may be related to the different LPS core structure. In conclusion, slight structural changes in PrAMPs significantly altered their binding sites and mechanisms of action, allowing for the design of different antibiotic classes.

Sensitive and specific serological ELISA for the detection of SARS-CoV-2 infections.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered the worldwide coronavirus disease 2019 (COVID-19) pandemic. Serological assays for the detection of SARS-CoV-2 infections are important to understand the immune response in patients and to obtain epidemiological data about the number of infected people, especially to identify asymptomatic persons not aware of a past infection. METHODS: We recombinantly produced SARS-CoV-2 nucleocapsid (N)-protein in Escherichia coli. We used the purified protein to develop an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of SARS-CoV-2 specific antibodies. This ELISA method was optimized and validated with serum samples collected from 113 patients with RT-PCR-confirmed SARS-CoV-2 infections including hospitalized COVID-19 patients and 1500 control sera mostly collected before 2015 with different clinical background. RESULTS: The optimized N-protein-ELISA provided a sensitivity of 89.7% (n = 68) for samples collected from patients with confirmed SARS-CoV-2 infections and mild to severe symptoms more than 14 days after symptom onset or a positive PCR test. The antibody levels remained low for serum samples collected in the first six days (n = 23) and increased in the second week (n = 22) post symptom onset or PCR confirmation. At this early phase, the ELISA provided a sensitivity of 39.1% and 86.4%, respectively, reflecting the time of an IgG immune response against pathogens. The assay specificity was 99.3% (n = 1500; 95% CI 0.995-0.999). Serum samples from persons with confirmed antibody titers against human immunodeficiency viruses 1/2, parvovirus B19, hepatitis A/B virus, cytomegalovirus, Epstein Barr virus, and herpes simplex virus were tested negative. CONCLUSIONS: We conclude that the N-protein-based ELISA developed here is well suited for the sensitive and specific serological detection of SARS-CoV-2 specific IgG antibodies in human serum for symptomatic infections. It may also prove useful to identify previous SARS-CoV-2 infections in vaccinated people, as all currently approved vaccines rely on the SARS-CoV-2 spike (S-) protein.

Metabolic Regulation of Macrophages by SIRT1 Determines Activation During Cholestatic Liver Disease in Mice.

BACKGROUND & AIMS: Inflammation is the hallmark of chronic liver disease. Metabolism is a key determinant to regulate the activation of immune cells. Here, we define the role of sirtuin 1 (SIRT1), a main metabolic regulator, in controlling the activation of macrophages during cholestatic liver disease and in response to endotoxin. METHODS: We have used mice overexpressing SIRT1, which we treated with intraperitoneal lipopolysaccharides or induced cholestasis by bile duct ligation. Bone marrow-derived macrophages were used for mechanistic in vitro studies. Finally, PEPC-Boy mice were used for adoptive transfer experiments to elucidate the impact of SIRT1-overexpressing macrophages in contributing to cholestatic liver disease. RESULTS: We found that SIRT1 overexpression promotes increased liver inflammation and liver injury after lipopolysaccharide/GalN and bile duct ligation; this was associated with an increased activation of the inflammasome in macrophages. Mechanistically, SIRT1 overexpression associated with the activation of the mammalian target of rapamycin (mTOR) pathway that led to increased activation of macrophages, which showed metabolic rewiring with increased glycolysis and broken tricarboxylic acid cycle in response to endotoxin in vitro. Activation of the SIRT1/mTOR axis in macrophages associated with the activation of the inflammasome and the attenuation of autophagy. Ultimately, in an in vivo model of cholestatic disease, the transplantation of SIRT1-overexpressing myeloid cells contributed to liver injury and fibrosis. CONCLUSIONS: Our study provides novel mechanistic insights into the regulation of macrophages during cholestatic disease and the response to endotoxin, in which the SIRT1/mTOR crosstalk regulates macrophage activation controlling the inflammasome, autophagy and metabolic rewiring.

[The Importance of Anatomy in the Training of the Vascular Surgeon]. / Der Stellenwert der Anatomie in der Weiterbildung des Gefäßchirurgen.

Vascular surgery has developed very dynamically in recent years, especially with the introduction of endovascular techniques. However, this has also changed surgeons' requirements. Classical surgical procedures have been almost completely displaced by endovascular techniques; new hybrid interventions have emerged while complex operations are concentrated in few centres. Therefore, developing expertise in open aortic surgery is increasingly challenging in vascular surgical training programs.Cadaver models provide an opportunity for exposure and repetitive training of individual surgical steps without endangering patients.As part of the training of highly complex vascular surgery operations, we carried out and evaluated the thoracoabdominal aortic replacement with 13 participants in 6 ethanol-preserved corpses.A simulation of surgical procedures on human cadaveric models cannot fully replace real experiences, but allows surgeons in training to practice and achieve dexterity in performing procedures in a safe and reproducible way.

Seroprevalences of specific antibodies against avian pathogens in free-ranging ring-necked pheasants (Phasianus colchicus) in Northwestern Germany.

Infectious diseases in captive pheasants (Phasianus colchicus) are well known, but there is a lack of knowledge about occurrence and distribution of pathogens in free-ranging pheasants in Germany. We investigated 604 sera from hunted pheasants and 152 sera from wild caught pheasants between 2011 to 2015, with the aim to determine the prevalence of specific antibodies against different viruses: Avian influenza virus (AIV) of subtypes H5, H7, H9, paramyxovirus type 1 (PMV-1), avian encephalomyelitis virus (AEV), infectious bursitis disease virus (IBDV), infectious bronchitis virus (IBV), infectious laryngotracheitis virus (ILTV), avian metapneumovirus (aMPV) and Salmonella sp., Mycoplasma synoviae (MS) and Mycoplasma gallisepticum (MG). In addition, 178 caeca were investigated for Histomonas meleagridis. The study reveals an ongoing circulation of IBV in the wild pheasant population during the study. Also high seroprevalences of specific antibodies against aMPV depending on the area and a strong increase in prevalence of IBDV antibodies in sera of pheasants in Lower Saxony were detected. ILTV antibody prevalences differed between areas and AEV antibody detection differed between years significantly, whereas specific antibodies against PMV-1 could not be detected and antibodies against AIV-H5, -H7 and -H9 and Mycoplasma spp. were detected in very few cases.

Towards the characterization of the hidden world of small proteins in Staphylococcus aureus, a proteogenomics approach.

Small proteins play essential roles in bacterial physiology and virulence, however, automated algorithms for genome annotation are often not yet able to accurately predict the corresponding genes. The accuracy and reliability of genome annotations, particularly for small open reading frames (sORFs), can be significantly improved by integrating protein evidence from experimental approaches. Here we present a highly optimized and flexible bioinformatics workflow for bacterial proteogenomics covering all steps from (i) generation of protein databases, (ii) database searches and (iii) peptide-to-genome mapping to (iv) visualization of results. We used the workflow to identify high quality peptide spectrum matches (PSMs) for small proteins (≤ 100 aa, SP100) in Staphylococcus aureus Newman. Protein extracts from S. aureus were subjected to different experimental workflows for protein digestion and prefractionation and measured with highly sensitive mass spectrometers. In total, 175 proteins with up to 100 aa (SP100) were identified. Out of these 24 (ranging from 9 to 99 aa) were novel and not contained in the used genome annotation.144 SP100 are highly conserved and were found in at least 50% of the publicly available S. aureus genomes, while 127 are additionally conserved in other staphylococci. Almost half of the identified SP100 were basic, suggesting a role in binding to more acidic molecules such as nucleic acids or phospholipids.

Appendicitis during the COVID-19 lockdown: results of a multicenter analysis in Germany.

PURPOSE: The COVID-19 pandemic has transformed medical care worldwide. General surgery has been affected in elective procedures, yet the implications for emergency surgery are unclear. The current study analyzes the effect of the COVID-19 lockdown in spring 2020 on appendicitis treatment in Germany. METHODS: Hospitals that provided emergency surgical care during the COVID-19 lockdown were invited to participate. All patients diagnosed with appendicitis during the lockdown period (10 weeks) and, as a comparison group, patients from the same period in 2019 were analyzed. Clinical and laboratory parameters, intraoperative and pathological findings, and postoperative outcomes were analyzed. RESULTS: A total of 1915 appendectomies from 41 surgical departments in Germany were included. Compared to 2019 the number of appendectomies decreased by 13.5% (1.027 to 888, p=0.003) during the first 2020 COVID-19 lockdown. The delay between the onset of symptoms and medical consultation was substantially longer in the COVID-19 risk group and for the elderly. The rate of complicated appendicitis increased (58.2 to 64.4%), while the absolute number of complicated appendicitis decreased from 597 to 569, (p=0.012). The rate of negative appendectomies decreased significantly (6.7 to 4.6%; p=0.012). Overall postoperative morbidity and mortality, however, did not change. CONCLUSION: The COVID-19 lockdown had significant effects on abdominal emergency surgery in Germany. These seem to result from a stricter selection and a longer waiting time between the onset of symptoms and medical consultation for risk patients. However, the standard of emergency surgical care in Germany was maintained.

Independent components of human brain morphology.

Quantification of brain morphology has become an important cornerstone in understanding brain structure. Measures of cortical morphology such as thickness and surface area are frequently used to compare groups of subjects or characterise longitudinal changes. However, such measures are often treated as independent from each other. A recently described scaling law, derived from a statistical physics model of cortical folding, demonstrates that there is a tight covariance between three commonly used cortical morphology measures: cortical thickness, total surface area, and exposed surface area. We show that assuming the independence of cortical morphology measures can hide features and potentially lead to misinterpretations. Using the scaling law, we account for the covariance between cortical morphology measures and derive novel independent measures of cortical morphology. By applying these new measures, we show that new information can be gained; in our example we show that distinct morphological alterations underlie healthy ageing compared to temporal lobe epilepsy, even on the coarse level of a whole hemisphere. We thus provide a conceptual framework for characterising cortical morphology in a statistically valid and interpretable manner, based on theoretical reasoning about the shape of the cortex.

Tuberculoid Granuloma in the Brainstem: Case Report

Meningitis or meningoencephalitis are the most common presentations of Koch bacilli infection on the central nervous system (CNS), especially in immunosuppressed patients, in whom the bacilli normally reaches the meninges and the cerebral parenchyma.. A least common pathological presentation is the tumoral growth pattern disease known as tuberculoma. This pathological entity is more common in the cerebral hemispheres and is rarely located in the brainstem. The present case report describes a case of a 55-year-old patient under regular antiretroviral therapy who was hospitalized with signs of brainstem and cerebellar disturbances. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain showed an exophytic lesion in the dorsal region of the pons. The patient underwent total resection of the lesion and the histopathologic analysis was consistent with a tuberculoma.

The yeast form of the fungus Candida albicans promotes persistence in the gut of gnotobiotic mice.

Many microorganisms that cause systemic, life-threatening infections in humans reside as harmless commensals in our digestive tract. Yet little is known about the biology of these microbes in the gut. Here, we visualize the interface between the human commensal and pathogenic fungus Candida albicans and the intestine of mice, a surrogate host. Because the indigenous mouse microbiota restricts C. albicans settlement, we compared the patterns of colonization in the gut of germ free and antibiotic-treated conventionally raised mice. In contrast to the heterogeneous morphologies found in the latter, we establish that in germ free animals the fungus almost uniformly adopts the yeast cell form, a proxy of its commensal state. By screening a collection of C. albicans transcription regulator deletion mutants in gnotobiotic mice, we identify several genes previously unknown to contribute to in vivo fitness. We investigate three of these regulators-ZCF8, ZFU2 and TRY4-and show that indeed they favor the yeast form over other morphologies. Consistent with this finding, we demonstrate that genetically inducing non-yeast cell morphologies is detrimental to the fitness of C. albicans in the gut. Furthermore, the identified regulators promote adherence of the fungus to a surface covered with mucin and to mucus-producing intestinal epithelial cells. In agreement with this result, histology sections indicate that C. albicans dwells in the murine gut in close proximity to the mucus layer. Thus, our findings reveal a set of regulators that endows C. albicans with the ability to endure in the intestine through multiple mechanisms.

Predicting potential distribution of poorly known species with small database: the case of four-horned antelope Tetracerus quadricornis on the Indian subcontinent.

Information gaps on the distribution of data deficient and rare species such as four-horned antelope (FHA) in Nepal may impair their conservation. We aimed to empirically predict the distribution of FHA in Nepal with the help of data from the Indian subcontinent. Additionally, we wanted to identify core areas and gaps within the reported range limits and to assess the degree of isolation of known Nepalese populations from the main distribution areas in India. The tropical part of the Indian subcontinent (65°-90° eastern longitude, 5°-30° northern latitude), that is, the areas south of the Himalayan Mountains. Using MaxEnt and accounting for sampling bias, we developed predictive distribution models from environmental and topographical variables, and known presence locations of the study species in India and Nepal. We address and discuss the use of target group vs. random background. The prediction map reveals a disjunct distribution of FHA with core areas in the tropical parts of central to southern-western India. At the scale of the Indian subcontinent, suitable FHA habitat area in Nepal was small. The Indo-Gangetic Plain isolates Nepalese from the Indian FHA populations, but the distribution area extends further south than proposed by the current IUCN map. A low to intermediate temperature seasonality as well as low precipitation during the dry and warm season contributed most to the prediction of FHA distribution. The predicted distribution maps confirm other FHA range maps but also indicate that suitable areas exist south of the known range. Results further highlight that small populations in the Nepalese Terai Arc are isolated from the Indian core distribution and therefore might be under high extinction risk.

Spatial niche partitioning in sub-tropical solitary ungulates: four-horned antelope and barking deer in Nepal.

Differential resource use allows a diversity of species to co-exist in a particular area by specializing in individual ecological niches. Four-horned antelope Tetracerus quadricornis is endemic to the Indian subcontinent and has a restricted distribution in Nepal and India; however, the barking deer Muntiacus vaginalis is relatively common throughout its wide distribution range. We wanted a better understanding of their habitats and how these two similarly sized solitary ungulates manage to coexist in lowland Nepal. We used fecal pellet belt transect surveys in the Babai valley, Bardia National Park to study the habitat associations of both species. We found empirical evidence that four-horned antelope prefer hill sal forest and deciduous hill forest at higher elevations, whereas barking deer preferred riverine and sal forest in lower elevations. We found a clear niche differentiation of four-horned antelope and barking deer that made the coexistence of these similarly sized solitary ungulates possible. Hence, resource partitioning is the key to coexistence of these solitary ungulates, and the fine-grained habitat mosaic of different forest types in the study landscape appears to be the underlying feature. Therefore, maintaining the habitat mosaic and preserving valuable hill sal and deciduous hill forests will facilitate the coexistence of herbivores in sub-tropical regions.