Epithelial zonation along the mouse and human small intestine defines five discrete metabolic domains

A key aspect of nutrient absorption is the exquisite division of labour across the length of the small intestine, with individual nutrients taken up at different proximal:distal positions. For millennia, the small intestine was thought to comprise three segments with indefinite borders: the duodenum, jejunum and ileum. By examining the fine-scale longitudinal transcriptional patterns that span the mouse and human small intestine, we instead identified five domains of nutrient absorption that mount distinct responses to dietary changes, and three regional stem cell populations. Molecular domain identity can be detected with machine learning, which provides a systematic method to computationally identify intestinal domains in mice. We generated a predictive model of transcriptional control of domain identity and validated the roles of Ppar-δ and Cdx1 in patterning lipid metabolism-associated genes. These findings represent a foundational framework for the zonation of absorption across the mammalian small intestine.

Epithelial TNF controls cell differentiation and CFTR activity to maintain intestinal mucin homeostasis

The gastrointestinal tract relies on the production, maturation, and transit of mucin to protect against pathogens and to lubricate the epithelial lining. Although the molecular and cellular mechanisms that regulate mucin production and movement are beginning to be understood, the upstream epithelial signals that contribute to mucin regulation remain unclear. Here, we report that the inflammatory cytokine tumor necrosis factor (TNF), generated by the epithelium, contributes to mucin homeostasis by regulating both cell differentiation and cystic fibrosis transmembrane conductance regulator (CFTR) activity. We used genetic mouse models and noninflamed samples from patients with inflammatory bowel disease (IBD) undergoing anti-TNF therapy to assess the effect of in vivo perturbation of TNF. We found that inhibition of epithelial TNF promotes the differentiation of secretory progenitor cells into mucus-producing goblet cells. Furthermore, TNF treatment and CFTR inhibition in intestinal organoids demonstrated that TNF promotes ion transport and luminal flow via CFTR. The absence of TNF led to slower gut transit times, which we propose results from increased mucus accumulation coupled with decreased luminal fluid pumping. These findings point to a TNF/CFTR signaling axis in the adult intestine and identify epithelial cell-derived TNF as an upstream regulator of mucin homeostasis.

Epithelial zonation along the mouse and human small intestine defines five discrete metabolic domains

A key aspect of nutrient absorption is the exquisite division of labor across the length of the small intestine, with individual classes of micronutrients taken up at different positions. For millennia, the small intestine was thought to comprise three segments with indefinite borders: the duodenum, jejunum, and ileum. By examining fine-scale longitudinal segmentation of the mouse and human small intestines, we identified transcriptional signatures and upstream regulatory factors that define five domains of nutrient absorption, distinct from the three traditional sections. Spatially restricted expression programs were most prominent in nutrient-absorbing enterocytes but initially arose in intestinal stem cells residing in three regional populations. While a core signature was maintained across mice and humans with different diets and environments, domain properties were influenced by dietary changes. We established the functions of Ppar-ẟ and Cdx1 in patterning lipid metabolism in distal domains and generated a predictive model of additional transcription factors that direct domain identity. Molecular domain identity can be detected with machine learning, representing the first systematic method to computationally identify specific intestinal regions in mice. These findings provide a foundational framework for the identity and control of longitudinal zonation of absorption along the proximal:distal small intestinal axis.

Tissue-specific mitochondrial HIGD1C promotes oxygen sensitivity in carotid body chemoreceptors

Mammalian carotid body arterial chemoreceptors function as an early warning system for hypoxia, triggering acute life-saving arousal and cardiorespiratory reflexes. To serve this role, carotid body glomus cells are highly sensitive to decreases in oxygen availability. While the mitochondria and plasma membrane signaling proteins have been implicated in oxygen sensing by glomus cells, the mechanism underlying their mitochondrial sensitivity to hypoxia compared to other cells is unknown. Here, we identify HIGD1C, a novel hypoxia-inducible gene domain factor isoform, as an electron transport chain Complex IV-interacting protein that is almost exclusively expressed in the carotid body and is therefore not generally necessary for mitochondrial function. Importantly, HIGD1C is required for carotid body oxygen sensing and enhances Complex IV sensitivity to hypoxia. Thus, we propose that HIGD1C promotes exquisite oxygen sensing by the carotid body, illustrating how specialized mitochondria can be used as sentinels of metabolic stress to elicit essential adaptive behaviors.

Single-cell multiomics defines tolerogenic extrathymic Aire-expressing cells with unique homology to thymic epithelium

The autoimmune regulator (Aire) protein, a key transcriptional regulator expressed in medullary thymic epithelial cells (mTECs), is crucial for central tolerance. Aire is also found in extrathymic Aire-expressing cells (eTACs) in secondary lymphoid organs. eTACs are hematopoietic antigen-presenting cells that are capable of inducing immune tolerance, but the precise identity of eTACs has remained unclear. To define eTACs, we utilized a combination of single-cell multiomics, transgenic murine models, and functional approaches. We found that eTACs consist of two similar cell types: CCR7+ Aire-expressing migratory dendritic cells and an Aire-high population co-expressing Aire and retinoic acid receptor–related orphan receptor γt (RORγt) that we termed Janus cells (JCs). eTACs, particularly JCs, have highly accessible chromatin and share remarkable homology with mTECs. Additionally, transgenic self-antigen expression by eTACs is sufficient to induce negative selection of cognate autoreactive T cells and prevent autoimmune diabetes. To better define the function of extrathymic Aire in eTACs and its contribution to peripheral immune tolerance, we have generated a Peripheral Aire KnockOut (PAKO) mouse (Vav1-Cre x Aire-fl/fl). Using intracellular Aire staining by flow cytometry, we validated that PAKO mice lack all eTACs in secondary lymphoid organs while maintaining normal thymic Aire expression in mTECs. Studying the biology of eTACs and peripheral Aire will help further elucidate the function of Aire and define basic peripheral tolerance mechanisms, which may have significance for a range of clinical applications from autoimmunity to tumor immunity to maternal-fetal tolerance.

Supported by ARCS Foundation

Comparison of Sequential Boost and Simultaneous Integrated Boost Volumetric Modulated Arc Therapy in Treatment of Head and Neck Carcinoma: A Prospective Interventional Study

Introduction: Volumetric Modulated Arc Therapy (VMAT) is a radiotherapy in head and neck cancer can be delivered by two boost techniques: Sequential Boost (SEQ) and Simultaneous Integrated Boost (SIB). There is still limited data comparing these two techniques. Aim: To compare SEQ and SIB planning techniques of VMAT in patients of Head And Neck Squamous Cell Carcinoma (HNSCC) in terms of disease response and acute toxicities. Materials and Methods: A prospective interventional study was conducted at Geetanjali Medical College and Hospital, Udaipur, Rajasthan, India from January 2019 to December 2020. Fifty two patients of HNSCC planned for radical chemoradiation were enrolled into two study arms SEQ-VMAT and SIB-VMAT. Chemotherapy given as weekly cisplatin 40 mg/m2 . Dosimetric comparison was done using Dose Volume Histogram (DVH) analysis. Response evaluation was done as per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 at 8-10 weeks follow-up. Acute toxicity evaluation was done as per Radiation Therapy Oncology Group (RTOG) toxicity grading. Statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 20.0 software. Results: A total of 52 subjects were included in the study, out of which 26 subjects were included in SEB group while 26 subjects in SIB group. No significant difference was observed in demographic data in terms of age 56.2 vs 53.5 years, sex (24 males and 2 females in both the arms), disease site (oropharynx is the most common site 38.5% in both arms)and stage (IVA 69.2% in SEQ arm vs 46.2% in SIB arm and III 30.8% in SEQ arm vs 42.3% in SIB arm). Dosimetric data was comparable between the two arms. SIB-VMAT shows significantly higher incidence of acute dermatitis (grade1 dermatitis at two weeks 69.2% vs 38.5%, p=0.0279 and grade 2 dermatitis at six weeks 84.6% vs 38.5%, p=0.0007) and acute mucositis (grade 1 mucositis at two weeks 84.6% vs 38.5%, p=0.0007) as compared to SEQ-VMAT. SEQVMAT shows significantly higher incidence of dysphagia (grade 1 at four weeks 84.5% vs 50%, p=0.0087). No significant differences were observed in terms of xerostomia and laryngeal toxicity.No significant difference in overall response was observed between SIB vs SEQ (complete response 65.4% vs 53.85% p=0.40). Conclusion: SEQ appears better in terms of acute toxicities but SIB was more convenient as no re-planning was required. For head and neck radiotherapy SIB and Sequential VMAT are comparable in terms of overall response.

Improved outcomes and staging in non-small-cell lung cancer guided by a molecular assay

There remains a critical need for improved staging of non-small-cell lung cancer, as recurrence and mortality due to undetectable metastases at the time of surgery remain high even after complete resection of tumors currently categorized as ‘early stage.’ A 14-gene quantitative PCR-based expression profile has been extensively validated to better identify patients at high-risk of 5-year mortality after surgical resection than conventional staging – mortality that almost always results from previously undetectable metastases. Furthermore, prospective studies now suggest a predictive benefit in disease-free survival when the assay is used to guide adjuvant chemotherapy decisions in early-stage non-small-cell lung cancer patients.

There is a need for improvement in the way early-stage non-small-cell lung cancers are staged and treated because many patients with ‘early-stage’ disease suffer high rates of cancer recurrence after surgery. In recent years, a specialized test has been developed to allow better characterization of a tumor's risk of recurrence based on the genes being expressed by tumor cells. Use of this test, in conjunction with standard staging methods, is better able to identify patients at high risk of cancer recurrence after surgery. Evidence suggests that giving chemotherapy to patients at high risk of recurrence after surgery reduces recurrence rates and improves long-term patient survival.

A human mutation in STAT3 promotes type 1 diabetes through a defect in CD8+ T cell tolerance

Naturally occurring cases of monogenic type 1 diabetes (T1D) help establish direct mechanisms driving this complex autoimmune disease. A recently identified de novo germline gain-of-function (GOF) mutation in the transcriptional regulator STAT3 was found to cause neonatal T1D. We engineered a novel knock-in mouse incorporating this highly diabetogenic human STAT3 mutation (K392R) and found that these mice recapitulated the human autoimmune diabetes phenotype. Paired single-cell TCR and RNA sequencing revealed that STAT3-GOF drives proliferation and clonal expansion of effector CD8+ cells that resist terminal exhaustion. Single-cell ATAC-seq showed that these effector T cells are epigenetically distinct and have differential chromatin architecture induced by STAT3-GOF. Analysis of islet TCR clonotypes revealed a CD8+ cell reacting against known antigen IGRP, and STAT3-GOF in an IGRP-reactive TCR transgenic model demonstrated that STAT3-GOF intrinsic to CD8+ cells is sufficient to accelerate diabetes onset. Altogether, these findings reveal a diabetogenic CD8+ T cell response that is restrained in the presence of normal STAT3 activity and drives diabetes pathogenesis.

Effect of Tamarindus indica leaf powder on plasma concentrations of copper, zinc, and iron in fluorotic cows

Aim:

The main objective of the study was to determine the deleterious effect of fluoride on plasma trace minerals of fluorotic cattle and to evaluate the effect of Tamarindus indica leaf powder toward correction of the same.

Materials and Methods:

A total of 30 cattle exhibiting chronic sign of fluorosis and 10 healthy cattle from nonfluorotic area were incorporated in this study. Fluorotic cattle were divided into three equal groups consisting of 10 cattle each. Group I from fluoride free area served as healthy control. The Group II received no treatment and served as disease control. Groups III and IV were supplemented with tamarind leaf powder at 15 g and 30 g/day with feed for 60 days. Plasma mineral status was evaluated after 60 days of treatment with double beam atomic absorption spectrophotometer.

Results:

Statistical analysis of data revealed a significant (p<0.05) decrease in mean plasma copper (Cu) (0.344±0.007 ppm), zinc (Zn) (0.692±0.06 ppm), and iron (Fe) concentration (1.100±0.01 ppm) in fluorotic cattle in comparison to healthy cattle (0.58±0.010, 2.342±0.04, 1.406±0.04 ppm, respectively). Significant (p<0.05) increase in Cu, Zn, and Fe was recorded after supplementation of tamarind leaf powder to the fluorotic cattle.

Conclusion:

It was concluded that fluorotic cattle might be supplemented with T. indica leaf powder with feed for the correction of the decreased level of certain plasma minerals.

Comparative anthelmintic efficacy of ivermectin delivered through different routes in gastrointestinal nematode infected dogs

Ivermectin is one of the most effective and widely used antiparasitic agents ever discovered because of its broad spectrum activity against nematodes and arthropods. Therefore, the study was conducted to determine the comparative anthelmintic efficacy of ivermectin by giving through oral and subcutaneous routes in clinically infected dogs and also to check the prevalence of gastrointestinal nematode in dogs in Bhubaneswar, Odisha. Total 154 dogs with clinical signs of gastroenteritis were examined for the presence of nematodal ova in their faecal sample and 64 were found positive (41.56 %). The screened dogs were divided in to two groups (n = 10 each), first group of animals were treated with ivermectin @ 0.5 mg/kg body weight by subcutaneous route and the second group with same dose of ivermectin through oral route. Efficacy of ivermectin was evaluated based on egg per gram (EPG), haematological and biochemical parameters. It is concluded that, Prevalence of gastrointestinal nematodes are high in dogs in the climatic condition of Bhubaneswar, Odisha. Ivermectin was found effective when administered through either of the routes. Haemato-biochemical parameters were restored after administration of ivermectin and also significant reduction in EPG was found in dogs treated with ivermectin by both the routes, but no significant difference was observed in EPG between oral and subcutaneous treated dogs in various intervals of study.

Laparoscopic management of transverse testicular ectopia with persistent mullerian duct syndrome

A 4-month-old male child presented with right undescended testis and left inguinal hernia with funiculitis. Ultrasonography showed funiculitis on the left side testis along with presence of 1.5 × 1 cm testis like structure just above left testis and empty right scrotal sac without any evidence of mullerian structures. On diagnostic laparoscopy, right testicular vessels were crossing from right to left and had uterus with both testes in left hernia sac. Mobilization of vessels, division of uterus, and hernia repair was done laparoscopically. On the review of literature, there is only one case report of total laparoscopic repair of transversetesticular ectopia (TTE) with hernia without persistent mullerian duct (PMDS). The uniqueness of our case is that it had TTE with hernia and PMDS, which were totally managed by laparoscopy. On 6 months of follow-up, both the testes are palpable in scrotum.

Haematology and serum biochemistry of chital (Axis axis) and barking deer (Muntiacus muntjak) reared in semi-captivity

Haematological and serum biochemical values of clinical significance that could serve as reference data for deer kept in captivity were measured for chital (Axis axis) and barking deer (Muntiacus muntjak). The venous blood from four each of chital and barking deer (n = 8) reared in semi-captivity was collected after proper restraint of the animals. The mean blood haemoglobin, packed cell volume, total erythrocyte count and total leukocyte count of all the eight deer of the two species were 15.90 +/- 0.44 g/dl, 51.44 +/- 0.60%, 20.83 +/- 0.57 x 10(6)/microl and 2.37 +/- 0.20 x 10(3)/microl. Serum total protein, albumin, bilirubin, cholesterol and blood urea nitrogen irrespective of species were 6.83 +/- 0.19 g/dl, 3.90 +/- 0.11 g/dl, 0.33 +/- 0.08 mg/dl, 106.81 +/- 3.59 mg/dl and 24.79 +/- 2.11 mg/dl, respectively. Serum enzyme activities indicative of liver function such as alanine transaminase (ALT) and aspartate transaminase (AST) were 30.38 +/- 4.67 units/ml and 42.88 +/- 5.97 units/ml, respectively. The serum calcium and phosphorus levels of all the eight deer were 10.27 +/- 0.36 mg/dl and 8.31 +/- 0.68 mg/dl, respectively. This is the first report on baseline values in barking deer. The distribution of haematological and serum biochemical values was fairly normal, suggesting that the mean values could be representative of normal values for two different deer species.

Strain-dependent anterior segment neovascularization following intravitreal gene transfer of basic fibroblast growth factor (bFGF)

BACKGROUND

A promising strategy for delaying death of photoreceptor cells in retinal degenerative disease is to support survival of these cells through intraocular delivery of growth/neurotrophic factors. One factor that has received great attention is basic fibroblast growth factor (bFGF; fgf-2), a known stimulator of angiogenesis. We evaluated the potential for neovascularization induced by adenovirus-mediated intravitreal delivery of bFGF.

METHODS

Recombinant adenoviruses carrying the low molecular weight (18 kD) or the high molecular weight (22, 23 and 24 kD) forms of human bFGF, driven by the cytomegalovirus (CMV) promoter/enhancer, were prepared. Viruses were delivered to eyes of different strains of mice and rats through intravitreal injection. Contralateral eyes were injected with control virus carrying a reporter gene [green fluorescent protein (GFP) or lacZ]. Transgene expression was assessed by Western analysis and by immunohistochemistry. Neovascularization was evaluated in vivo and histologically at termination of the experiment.

RESULTS

Adenovirus-mediated delivery of the 18 kD form of bFGF resulted in anterior segment neovascularization in a strain-dependent fashion. Generation of new blood vessels was not observed after injection of the higher molecular weight forms of bFGF or of control solutions.

CONCLUSION

The low molecular weight form (18 kD) (but not the high molecular weight forms) of bFGF drives angiogenic response in the anterior segment of specific strains of mice. Genetic modifiers may contribute to and/or prevent neovascularization induced by bFGF.

The International Health Program: the fifteen-year experience with Yale University's Internal Medicine Residency Program

The purpose of this study was to assess the impact of international health electives on physicians-in-training. A retrospective study was conducted using an anonymous, self-administered mailed survey to internal medicine residents who trained at Yale from 1982 to 1996 based on their experience with our International Health Program (IHP). The response rate was 61%, with 96 completed surveys in the participant group and 96 completed surveys in the nonparticipant group. Participants were more likely than nonparticipants to care for patients on public assistance (77 versus 49; P < 0.001) and immigrant patients (41 versus 23; P = 0.006). Among residents who changed their career plans, participants (22) were more likely than nonparticipants (14) to switch from subspecialty medicine to general medicine (P = 0.02). Participants were significantly more likely to have a positive view of health care delivery in developing countries. Compared with nonparticipants (64), IHP participants (74) believed that the physical examination is under-used by physicians from the United States as a diagnostic skill (P = 0.03). International health experiences appeared to have an important impact on the decisions and attitudes of residents.

Basic fibroblast growth factor induces a transformed phenotype in normal human melanocytes

Basic fibroblast growth factor (bFGF or FGF-2) is produced by nearly all melanomas in vitro and in vivo but not by normal melanocytes, which require exogenous bFGF for growth. In this study, we transduced normal human melanocytes to overexpress two forms of bFGF: (bFGF-Long and bFGF-Short) using replication-deficient adenovirus 5 vectors. bFGF-Long induced the 17.8, 22.5, 23.1 and 24.2 kDa forms of bFGF, whereas bFGF-Short induced only the 17.8 kDa mature form. Growth of cultured melanocytes transduced with either vector was similar to that of nevus and melanoma cells and was independent of exogenous bFGF and of insulin/insulin-like growth factor 1, and cyclic AMP enhancers, requiring only phorbol ester as an exogenous mitogen. Like primary melanoma cells, transduced normal melanocytes grew anchorage independently in soft agar. When injected into the dermis of human skin grafted to mice, bFGF-transduced melanocytes proliferated for at least 20 days, whereas cells from control cultures showed poor survival and no proliferation. These results demonstrate that bFGF upregulation is a critical component in melanoma progression.

Stable transgene expression in rod photoreceptors after recombinant adeno-associated virus-mediated gene transfer to monkey retina

Recombinant adeno-associated virus (rAAV) is a promising vector for therapy of retinal degenerative diseases. We evaluated the efficiency, cellular specificity, and safety of retinal cell transduction in nonhuman primates after subretinal delivery of an rAAV carrying a cDNA encoding green fluorescent protein (EGFP), rAAV. CMV.EGFP. The treatment results in efficient and stable EGFP expression lasting >1 year. Transgene expression in the neural retina is limited exclusively to rod photoreceptors. There is neither electroretinographic nor histologic evidence of photoreceptor toxicity. Despite significant serum antibody responses to the vector, subretinal readministration results in additional transduction events. The findings further characterize the retinal cell tropism of rAAV. They also support the development of studies aimed ultimately at treating inherited retinal degeneration by using rAAV-mediated gene therapy.

Temporal and spatial regulation of gene expression mediated by the promoter for the human tissue inhibitor of metalloproteinases-3 (TIMP-3)-encoding gene

A complex interplay between enzymes involved in extracellular matrix formation and their inhibitors is thought to control organogenesis during mammalian development. Disturbance of this balance may result in a wide range of diseases, including macular degeneration, arthritis, and tumor metastases. In order to define elements which may be involved in regulating human tissue inhibitor of metalloproteinase 3 (TIMP3) expression, we isolated and sequenced a clone containing 1315 bp of the 5'-upstream region of the human TIMP-3-encoding gene. A 1.2 kb fragment of this clone, which contains multiple motifs which are binding sites for known transcription factors, was used to drive expression of the lacZ reporter gene in multiple lines of transgenic mice. TIMP3 promoter activity, detected through beta-galactosidase histochemical assay, was observed at high levels in selected tissues, the identity of which varied according to developmental stage. TIMP3 promoter activity was detected at embryonic and early postnatal stages in tissues undergoing extensive remodeling, such as developing somites, bones and joints, choroid plexus, webs between the digits, and the spongiotrophoblastic portion of the placenta. In adulthood, TIMP3 promoter activity was restricted to a few tissues which exhibit high metabolic activity or rapid turnover. These include the retinal pigment epithelium (RPE), cells of the kidney cortex, hair follicles, gingiva, ovarian follicles, and testis. The results suggest that TIMP3 expression plays an active role in developmental patterning and in the maintenance of specific differentiated tissues.

Magnesium protects against cocaine-induced hemorrhagic stroke in a rat model: a 31P-NMR in-vivo study

In-vivo 31P-nuclear magnetic resonance (NMR) studies were undertaken with anesthetized rats to determine: a. whether systemic administration of MgCl2 could protect animals against cocaine-induced hemorrhagic stroke, and b. whether a relationship exists between basal levels of brain intracellular free magnesium ions ([Mg2+]i), phosphometabolites, and stroke risk. Repeat 31P-NMR spectra were obtained at various intervals of time (3-120 min, or up until death) after administration of cocaine (5 + 30 mg/kg). Ion selective electrodes were used to measure plasma Mg2+, K+, Na+ and Ca2+. Forty percent of animals died in the absence of Mg2+ infusion following high dosage of cocaine. Only 13% died with cocaine following Mg2+ infusion (p <0.005). In the Mg2+-protected animals, neither brain [Mg2+]i,intracellular pH (pHi), [phosphocreatine-PCr]/[ATP], nor brain [inorganic phosphate-Pi]/[ATP] fell when toxic and lethal doses of cocaine were given. Low basal brain [Mg2+]i (275 +/- 24 vs. 466 +/- 35 microM, p <0.01) and low basal brain [PCr] (3.36 +/- 0.35 vs. 4.26 +/- 0.24 mM, p <0.01) were found to be associated with a 3-fold increased incidence of stroke. A positive correlation (r = 0.31, p <0.03) between brain [Mg2+]1 and [PCr]/[ATP] was found. It is possible that both brain [Mg2+]i and [PCr] may be useful as important predictors of susceptibility to cocaine-induced hemorrhagic stroke.

COMBINED SPINAL AND EPIDURAL ANAESTHESIA FOR ABDOMINAL SURGERY: A NEW TECHNIQUE

Combined spinal and epidural anaesthesia was used in 50 patients undergoing abdominal surgery. A fixed dose of 1.0 mL of 5 per cent lignocaine was injected intrathecally in all cases followed by 10 mL of 0.5 per cent bupivacaine epidurally, using "needle through needle" technique in the same lumbar intervertebral space. Subsequently epidural catheter was passed for top-up doses and postoperative analgesia. The advantages of this technique observed were immediate onset of intense block of prolonged, controllable duration and no incidence of post-spinal headache. Five cases developed intraoperative hypotension which required correction. No patient developed any complications of spinal and epidural anaesthesia.

Antibiotic production by submerged culture of Melanconis flavovirens (Otth) Wehm

The pyrenomycete Melanconis flavovirens under submerged cultivation produced antibiotics active against both bacteria and fungi. Glucose and corn-steep liquor were the best C and N sources for the antibiotic production, respectively. Supplementation with Tween-80 and enthylene glycol stimulated both antifungal and antibacterial antibiotic production, whereas oleic acid only the antifungal one. Addition of K2HPO4 also showed a positive effect. The optimal conditions for fermentation of the antifungal component are given.

Effect of phosphate on ergot alkaloid synthesis in Aspergillus fumigatus

High concentration of inorganic phosphate in the culture medium of Aspergillus fumigatus inhibited ergot alkaloid synthesis. Addition of L-tryptophan but not mevalonate or 5-methyltryptophan to the above culture restored the alkaloid synthesis to the level found in normal cultures. The decrease in alkaloid synthesis in the fungus accompanies an increase in cell mass, cellular protein and sterol content. Aspartate aminotransferase and alanine aminotransferase activities were significantly increased in the high-phosphate culture.

Phosphate uptake and involvement of binding protein in Tween-80 supplemented culture of Aspergillus fumigatus

Tween-80 supplementation in submerged culture of Aspergillus fumigatus resulted in an increase of phosphate uptake. The uptake system was characterized as saturable, energy-dependent and operating against the concentration gradient. Control and Tween 80 cultures showed similar Km values for phosphate uptake (50 micrometer). Cold osmotic shock treatment of the cultures was found to cause considerable reduction in the ability to take up phosphorus with concomitant release of the binding protein into the shock fluid. Binding protein preparation from Tween-80 supplemented cells showed more activity than that from control cells.