Uncovering the microbial community structure and physiological profiles of terrestrial mud volcanoes: a comprehensive metagenomic insight towards their Trichloroethylene biodegradation potentiality.

Mud volcanoes are dynamic geological features releasing methane (CH4), carbon dioxide (CO2), and hydrocarbons, harboring diverse methane and hydrocarbon-degrading microbes. However, the potential application of these microbial communities in chlorinated hydrocarbons bioremediation purposes such as trichloroethylene (TCE) has not yet been explored. Hence, this study investigated the mud volcano's microbial diversity functional potentiality in TCE degradation as well as their eco-physiological profiling using metabolic activity. Geochemical analysis of the mud volcano samples revealed variations in pH, temperature, and oxidation-reduction potential, indicating diverse environmental conditions. The Biolog Ecoplate™ carbon substrates utilization pattern showed that the Tween 80 was highly consumed by mud volcanic microbial community. Similarly, MicroResp® analysis results demonstrated that presence of additive C-substrates condition might enhanced the cellular respiration process within mud-volcanic microbial community. Full-length 16S rRNA sequencing identified Proteobacteria as the dominant phylum, with genera like Pseudomonas and Hydrogenophaga associated with chloroalkane degradation, and methanotrophic bacteria such as Methylomicrobium and Methylophaga linked to methane oxidation. Functional analysis uncovered diverse metabolic functions, including sulfur and methane metabolism and hydrocarbon degradation, with specific genes involved in methane oxidation and sulfur metabolism. These findings provide insights into the microbial diversity and metabolic capabilities of mud volcano ecosystems, which could facilitate their effective application in the bioremediation of chlorinated compounds.

In vitro and In vivo Determination of Biological Activities of Bitter Gourd (Momordica charantia L.) Peel, Flesh and Seeds.

Momordica charantia L. has been remained a well-known medicinal vegetable used traditionally. However, which part is most effective against which disorder, has been remained undiscovered yet. The objective of this study was to examine the antimicrobial, antihyperlipidemic and antihyperglycemic activities of peel, flesh, and seeds of bitter gourd, through in vitro and in vivo assays. Ethanolic extracts from powders of three fractions of bitter gourd were assessed for antimicrobial potential against bacterial and fungal strains, whereas, powders of these fractions were used to determine antihyperlipidemic and antihyperglycemic activity, in alloxan induced diabetic rats. Our results showed that BSE exhibited better antimicrobial activity against Bacillus cereus, whereas BFE exhibited better against Escherichia coli. Blood glucose was significantly lowered by all three powders in a dose dependent manner, when fed to diabetic rats, with the highest decrease by BSP, which reduced the glucose level from 296.20 ± 2.00 mg/dl to 123.10 ± 0.80 mg/dl, at 15 mg dose, after 28 days trial. Elevated levels of TC (101.18 ± 0.65 mg/dl), TG (83.69 ± 0.61 mg/dl) and LDL-C (25.90 ± 0.09 mg/dl) in positive control rats were lowered down in well manners by BSP at 15 mg dose, to 86.30 ± 0.53, 67.70 ± 0.53 and 19.32 ± 0.06 mg/dl, respectively. As compared to BFP and BPP, BSP showed significant involvement in antibacterial, antihyperglycemic, and antihyperlipidemic actions. Along with the edible flesh, peels and seeds, which are usually discarded as waste, could also be utilized for development of pharma foods capable of promoting health.

Physiological and biochemical variations of naturally ripened mango (Mangifera Indica L.) with synthetic calcium carbide and ethylene.

To meet the increasing consumer demands for fruits, the implementation of artificial ripening techniques using synthetic chemicals has become increasingly commonplace among less ethical fruit production companies in today's global market. The objective of present work was to establish a difference in the physiological and biochemical and profiles of naturally ripened mangoes vs. those ripened by application of synthetic calcium carbide and ethylene. The application of calcium carbide at 10 g/kg mangoes resulted early ripening in 2 days, with a 3-day shelf life, as compared with 5 and 6 days, for mangoes ripened by ethylene and naturally, respectively. Higher levels of calcium carbide reduced moisture, fiber, protein and carbohydrates content and increased the ash content of mangoes, as compared to higher levels of ethylene, whereas in naturally ripened mangoes the content percentages were 80.21, 3.57, 3.05 6.27 and 4.74, respectively. Artificial ripening resulted in significant loss of ascorbic, citric and malic acid, as values were recorded 35.94, 2.12 and 0.63 mg/g, respectively, in mangoes ripened with 10 g/kg of calcium carbide. However, in naturally ripened mangoes the amounts of these acids were recorded significantly (p < 0.05) high as 52.29, 3.76 and 1.37 mg/g, respectively. There was an increase in total soluble solids (TSS) and reducing sugars, and a decrease in titratable acidity in calcium carbide (10 g/kg) treated mangoes. Elemental analyses revealed high levels of minerals in naturally ripened mangoes, with significant values of iron (0.45 mg/100 g), zinc (0.24 mg/100 g) and copper (0.17 mg/100 g). The organoleptic quality of the fruit decreased significantly (p < 0.05) as a result of the use of calcium carbide. Although use of artificial ripening techniques provides speedy ripening of mangoes, there are obvious limitations. Consequently, natural ripening should be promoted in order to have safer and more nutritious mangoes.

Drug susceptibility, Prevalence and effect of Pseudomonas aeruginosa on wound healing of burn patients.

Objective: To determine the prevalence, antibiotic susceptibility and effect of Pseudomonas aeruginosa in relation to burn patients. METHODS: The cross-sectional study was conducted at the Centre for Advanced Studies in Vaccinology and Biotechnology, University of Balochistan, Quetta, Pakistan, from March 2018 to May 2021, and comprised pus swab cultures were isolated from inpatients with 2nd and 3rd degree burns aged up to 60 years at Bolan Medical Complex Hospital and Sandeman Provinical Hospital, the two main government tertiary care hospitals in Quetta. The samples were immediately cultured, and evaluated using biochemical tests, antibiotic susceptibility and molecular identification using polymerase chain reaction. Data was analysed using SPSS 20. RESULTS: Of the 720 burn wound samples, 424(58.9%) were positive for Pseudomonas aeruginosa; 304(42%) males and 120(16%) females (p<0.02). The overall mean age of the patients was 27.7±6.2 years (range: 1-60 years). The mean total burn surface area was not significantly different in positive 29.6±6.2% and negative 30.3±6.2% cases (p>0.05). The time leading to skin grafts in positive patients was 29.5±6.5 days compared to 22.3±6.3 days for negative patients (p< 0.007), and the time required for wound healing was 25.0±4.7 days and 16.7±5.2 days, respectively (p<0.001). Length of hospital stay of Pseudomonas aeruginosa positive patients was 38.0±7.8 days compared to 32.1±6.8 days for negative patients (p<0.001). Conclusion: Nosocomial infections and multidrug resistance species were observed frequently at the burn wound site. P. aeruginosa.

Food Application of Orange Seed Powder through Incorporation in Wheat Flour to Boost Vitamin and Mineral Profiles of Formulated Biscuits.

The significance of conducting research for its application has been noted as a result of the rising global food production and waste generation. As a result, there is increasing interest in fruits and vegetable seeds that contain bioactive chemicals, such as those that are obtained from orange seeds. In the current work, orange seed powder replaced wheat flour at 0, 2.5, 5, 7.5, and 10% levels, to observe changes in physicochemical features of developed biscuits. Proximate analysis of orange seed powder and wheat flour revealed that orange seed powder has high fat, fiber, protein, and ash contents as compared to wheat flour, whereas moisture contents in wheat flour were high. In developed biscuits, the highest values (percentage) of ash (9.68 ± 0.04), fiber (6.79 ± 0.12), protein (10.42 ± 0.25), and fat (36.90 ± 0.55) were found in biscuits developed with 10% orange seed powder. Orange seed powder was a comparatively good source of both macro and micro minerals, as compared to wheat flour. High contents of selenium (5.32 ± 0.03), iron (2.12 ± 0.05), zinc (3.88 ± 0.12), and manganese (2.25 ± 0.04) mg/100 g, present in orange seed powder, were the prominent findings of this research work, as wheat flours were observed to be deficient in these trace minerals. Contents of calcium, magnesium, potassium, zinc, manganese, zinc, and selenium in control biscuits were found 20.51 ± 0.08, 17.29 ± 0.04, 46.12 ± 0.05, 1.06 ± 0.01, 1.97 ± 0.01, 0.12 ± 0.01, and 0.11 ± 0.01 mg/100 g, respectively, and replacement of wheat flour with 10% orange seed powder increased values of these minerals to 103.90 ± 0.35, 44.35 ± 0.50, 71.29 ± 0.32, 2.59 ± 0.4, 2.75 ± 0.02, 1.31 ± 0.01, and 2.02 ± 0.05 mg/100 g, respectively. Vitamins E and K, which were not detected in wheat flour, were present in orange powder in high amount, whereas B group vitamins, which were also present in wheat flour, were observed in significantly high quantities in orange seed powder. Increment in vitamin A, D, E, K, and B complexes was significant as a result of orange seed powder supplementation, except for vitamins B1 and B2, which were slightly decreased. Sensory evaluation revealed that a 5% replacement of orange seed powder provided good quality biscuits with acceptable colour, flavor, taste, texture, and overall acceptability. Orange seed powder could prove an important ingredient in the baking industry with the potential of promoting the nutritional value of foods.

Synergistic effect of microwave heating and thermosonication on the physicochemical and nutritional quality of muskmelon and sugarcane juice blend.

Melons (Cucumis melo L.) are highly popular due to its delicate and delightful flavor in the worldwide. However, the flavor of the melon juice was easily affected by thermal treatments and unpleasant cooking smell during production process. Sugarcane (Saccharum officinarum) juice is a proven nutritious beverage with high levels of antioxidants, polyphenols, and other beneficial nutrients. Due to its low sugar content, combined with sugarcane, muskmelon-sugarcane blend juice gives an appealing and exotic drink. The research was planned to evaluate the effect of thermo-sonication (20 kHz, 70% amplitude, 5, 10 and 15 min) and microwave (90 °C, 400 W, 120 sec) on physicochemical parameters including pH, titratable acidity, total soluble solids (TSS), total phenolic contents (TPC), total flavonoid contents (TFC) and antioxidant capacity of muskmelon and sugarcane juice blend, during storage of 90 days at refrigeration (4±1 °C). The statistical results showed that synergism of sonication and microwave treatments had a significant (p ≤ 0.05) influence on pH, TSS, titratable acidity, TPC, TFC and antioxidant capacity. T3 (15 min of sonication and 120 s of microwave) showed the maximum TSS (12.00±0.40 °B), pH (5.07±0.02), TPC (484.33±10.41 mg GAE/100 mL), TFC (261.73±11.32 mg CE/100 mL), and antioxidant activity (381.62±17.72 µg AAE/100 mL), as compared to untreated samples. Thermosonication for 15 min caused maximum retention of TPC, TFC and antioxidant capacity of blend juice during 90 days of storage, whereas in untreated samples these parameters were found highly decreased during storage. Thus, sonication and microwave can be recommended as an alternative to both conventional pasteurization processes and chemical preservatives.

Reliable and cost-efficient protection scheme for 5G fronthaul/backhaul network.

One of the challenges for Mobile Network Operators (MNO) in 5G deployment is to ensure reliability in the various sections of the network as the new services and applications, for instance, video on demand, telemedicine, online learning, smart transportation and augmented reality require not only high bandwidth but also demand uninterrupted service. However, this reliability requires substantial investment. Therefore, MNO only deploys protection or backup resources in the network unless it is cost-effective. The study aims to present a reliable and low-cost protection scheme based on an Ultra-Dense Wavelength Division Multiplexing Passive Optical Network (UDWDM PON) for the transport layer of the 5G network, i.e., for the fronthaul/backhaul section. We have evaluated the Capital Expenditure (CAPEX) cost of UDWDM PON with and without protection in a dense urban area. We also measure the figure of merit between the cost and reliability of the system and, subsequently, confirm that the proposed protection scheme can achieve system reliability up to four nines with very low additional CAPEX investment. Finally, the efficacy of the proposed protection scheme is also demonstrated through simulation experiments.

In Vitro Role of Pumpkin Parts as Pharma-Foods: Antihyperglycemic and Antihyperlipidemic Activities of Pumpkin Peel, Flesh, and Seed Powders, in Alloxan-Induced Diabetic Rats.

Pumpkin is a well-known vegetable, among the members of Cucurbitaceae family, due to its importance as pharma food. Keeping in view the antidiabetic and plasma lipids lowering potential of pumpkin, the present study was conducted to investigate that, which part of pumpkin (peel, flesh, and seeds), possess more bioactive compounds, exhibiting antihyperglycemic and antihyperlipidemic potential. Albino rats with 190-210 g body weight were divided into 11 groups. Five rats were included in each group; group A was negative control, group B was positive control, and groups C to K were diabetic rats fed with pumpkin peel, flesh, and seed powders. Diabetes was induced in rats with the help of alloxan monohydrate. During 28 days of experimental period, blood glucose level of different rat's groups was checked with the help of glucometer, at every 7 days interval and at the end of 28 days study, plasma lipids were checked with the help of commercial kits. A significant decrease in blood glucose level (128.33 ± 1.67 mg/dl), TC (88.43 ± 0.66 mg/dl), TG (69.79 ± 0.49 mg/dl), and LDL-C (21.45 ± 0.08 mg/dl) was recorded in rat groups fed with 15 g pumpkin seed powder, at the end of study. After pumpkin seeds, second significant antihyperglycemic and antihyperlipidemic effect was recorded in rat's groups fed with 15 g pumpkin peel powder. Pumpkin flesh powder effect in lowering blood glucose level and plasma lipids was less significant as compared to seeds and peel powder. As the dose of the pumpkin powders was increased from 5 to 10 and then 15 g, the blood glucose-lowering and plasma lipid-lowering effect became more significant. Similarly, as the experimental duration was expanded from first week to 28 days, this antihyperglycemic and antihyperlipidemic effect became more significant. These results were sufficient to conclude that pumpkin has high potential to be used in human diet to cope with noncommunicable diseases like diabetes and hypercholesterolemia.

Nutritional health status: association of stunted and wasted children and their mothers.

BACKGROUND: Across the globe, 149 and 49 million children are stunted and wasted, respectively. Prevalence of stunting and wasting is 40.2 and 17.7% in children of Pakistan. Stunting and wasting are accompanied with genetics, dietary factor, lack of information, bottle feeding, illiterate parents, less birth interval, infection such as diarrhoea, low birth weight, mother suffering from malnutrition during pregnancy, breastfeeding, pharmaceutical, and hormonal, psychosocial, and low social-economic status. METHODS: Stunted and wasted children and their mothers were called on and detail discussions related to research plan were carried out. Informed consent was assured from mothers, for participation in the study. The demographics, anthropometrics, vital signs observations, body composition, clinical signs and symptoms, dietary intake and associated biomarkers (CBC, level of urea nitrogen in blood, serum albumin globulin and serum creatinine.) were tools for nutritional health status assessment. SPSS software was implied on data. RESULTS: The study found that 27.2% mothers were belonged to stunted children, 17.3% belonged to wasted children, and 50.9% belonged to those children who were suffering from both stunting and wasting condition.57.9% mothers who were illiterate belong to stunted and wasted children. CBC and Hb test was prominent, stunted and wasted children had Hb 9.88 mg/dL, whereas, their mothers had 10.8 mg/dL as average Hb. The average height and weight of stunted and wasted children was 68.6 cm and 7.11 kg respectively. Dietary patterns and diet quality of both mothers and children were poor, due to lack of affordability; they were not able to eat healthy food. CONCLUSION: Stunting and wasting ultimately resulted in poor growth and development of children. Most of children were anemic, they height and weight less than WHO growth standards. They had less knowledge and poor intake of food diet pattern so children growth was poor.

Utilization of pumpkin, pumpkin powders, extracts, isolates, purified bioactives and pumpkin based functional food products: A key strategy to improve health in current post COVID 19 period: An updated review.

Progression of today's world has been given setback due to the adversity of a novel, viral and deadly outbreak COVID 19, which raised the concerns of the scientists, researchers and health related officials about the inherent and adaptive immune system of the living body and its relation with healthy diet balanced with pharma foods. Choice of right food can help to build and boost adaptive immunity and pumpkin due to excellent profile of functional and nutraceutical constituents must be the part of both infected and non-infected person's daily diet. Vitamins, minerals, phenolic acids, essential oils, peptides, carotenoids and polysaccharides present in pumpkin could accommodate the prevailing deficiencies in the body to fought against the pathogens. Pumpkins are well equipped with nutraceuticals and functional ingredients therefore, consumption and processing of this remarkable fruit must be encouraged as pharma food due to its antihyperlipidemic, antiviral, anti-inflammatory, antihyperglycemic, immunomodulatory, antihypertensive, antimicrobial and antioxidant potential, and these pharmacological properties of pumpkin are directly or indirectly related to the COVID 19 outbreak. Utilization of pumpkin has a domain in the form of powders, extracts, isolates, and pumpkin incorporated food products. A wide range of healthy, nutritious and functional food products has been developed from pumpkin, which includes juice, soup, porridge, chips, biscuits, bread, cake, bar and noodles. In recent times some innovative and novel technologies have been applied to process and preserve pumpkin for its enhanced shelf life and bioaccessibility of nutrients. Need of healthy eating in current post COVID 19 period is very crucial for healthy population, and medicinal foods like pumpkin, and bioactive compounds present in this functional food could play a vital role in developing a healthy community around the globe.

Epidemic and PCR-based identification of vibrio cholera through OmpW gene from diarrhoeal patients admitted at different hospitals of Baluchistan.

OBJECTIVE: To study the different epidemiological and polymerase chain reaction-based identification of vibrio cholera. METHODS: The cross-sectional study was conducted at the Center for Advanced Studies in Vaccinology and Biotechnology, University of Balochistan, Quetta, Pakistan, from January 5 to December 6, 2019, and comprised faecal / rectal swab samples from patients with a history of untreated severe diarrhoea of <12-hour duration. The samples were collected from suspected cholera patients at different hospitals of the province. The isolates were examined and identified on the basis of colony characters on thiosulfate-citrate-bile salts-sucrose agar. Susppected colonies were subjected to gram staining, biochemical tests and polymerase chain reaction-based identification. Data was analysed using SPSS 19. RESULTS: Of the 444 samples, 33(7.43%) were positive for vibrio cholera and 411(92.56%) were negative. The incidence was higher in individuals aged 1-20 years 12(2.7%); males 18(4.05%); Balochs 18(4.05%); lower socioeconomic class 18(4.05%); and illiterates 26(5.85%). The incidence was more in summer 19(4.27%) and spring 8(1.80%) seasons. Polymerase chain reaction was highly effective diagnostic approach, with findings showing clear bands of 588bp of ompW gene. CONCLUSIONS: Surveillance for diarrhoeal disorders is necessary to control future outbreaks of cholera in the region.

Epidemiological and pathological characteristics of Cutaneous Leishmaniasis from Baluchistan Province of Pakistan.

Cutaneous Leishmaniasis (CL) is considered a neglected tropical disease which in Pakistan can now be considered as a growing public health problem. The exact figures on the magnitude of the disease are lacking both at the national and regional level and only a few health centres are available for diagnosis of CL. The present study was designed to identify the epidemiology of CL infection from August 2018 to December 2019 and to assess clinical aspects of CL in Baluchistan Province of Pakistan. A total of 4072 clinically suspected CL cases were analysed statistically. The highest number of CL cases were reported in May, followed by April, January and then July, February and June and the lowest number of cases were observed in March and November. The highest prevalence rate was found in males where 38% of reported cases were aged 0-9 years. The majority (24.4%) of lesions were found on the hands followed by the face in which cheeks, ears and nose were the effected organs. About 50% of the participants have single lesion while 14% of the participants had two and nearly 3% of the participants have six lesions. The atypical clinical presentations were observed in Baluchistan and common unusual presentations were lupus erythematosus. The study findings suggest that more epidemiological studies and health education campaigns are needed for the population awareness regarding CL in Baluchistan. It is recommended that risk factors should be evaluated to establish control and management strategies to prevent disease at the individual and community level.

In Vivo Screening and Antidiabetic Potential of Polyphenol Extracts from Guava Pulp, Seeds and Leaves.

The present study investigates the antidiabetic potential of polyphenol extracts purified from guava pulp, seeds and leaves using an in vivo experiment on albino rats. The polyphenols from guava pulp, seeds and leaves were extracted using methanol solvent and the sonication method while being evaluated by total phenolic contents and radical scavenging activity assay. The proximate composition of powders revealed that ash, protein and total sugars were significantly (p < 0.05) higher in leaves and seeds, while vitamin C was highest in pulp. Total phenolic and antioxidant activities were highest in pulp followed by leaves and seeds. The findings of feed intake and body gain revealed that the supplementation of polyphenols, especially from pulp, significantly (p < 0.05) increased the feed intake, which resulted in increased body weight. Moreover, total cholesterol (TC) and low-density lipoprotein (LDL) levels were significantly (p < 0.05) decreased, while the level of high-density lipoprotein (HDL) was increased in groups fed with polyphenols from guava pulp compared to both (+ive and -ive) control groups. Furthermore, blood glucose and triglycerides were significantly (p < 0.05) decreased in supplemented groups compared to the control group of diabetes mice, which resulted in the inhibition of α-amylase and glucose transport. Besides this, packed cell volume (PCV), mean corpuscular volume (MCV), hemoglobin, red blood cells (RBCs), white blood cells (WBCs) and platelet levels were increased significantly (p < 0.05) in pulp's extract followed by leaves and seeds compared to both control groups. Overall, the antidiabetic potential of different extracts was in the following order: pulp > leaves > seeds. The findings suggest the feasibility of adding 200-250 mg/kg.bw of polyphenol extracts of pulp as an alternative to diabetic drugs.

Computational modeling and functional characterization of a GgChi: A class III chitinase from corms of Gladiolus grandiflorus.

The present study describes the predicted model and functional characterization of an endochitinase (30 kDa) from corms of Gladiolus grandiflorus. ESI-QTOF-MS generated peptide showed 96% sequence homology with family 18, Class III acidic endochitinase of Gladiolus gandavensis. Purified G. grandiflorus chitinase (GgChi) hydrolyzed 4-methylumbelliferyl ß-d-N,N',N''-triacetylchitotriose substrate showing specific endochitinase activity. Since no structural details of GgChi were available in the Protein Data Bank (PDB), a homology model was predicted using the coordinate information of Crocus vernus chitinase (PDB ID: 3SIM). Ramachandran plot indicated 84.5% in most favored region, 14.8% in additional and 0.6% in generously allowed region while no residue in disallowed region. The predicted structure indicated a highly conserved (ß/α)8 (TIM barrel) structure similar to the family 18, class III chitinases. The GgChi also showed sequence and structural homologies with other active chitinases. The GgChi (50 µg/disc) showed no antibacterial activity, but did provide mild growth inhibition of phytopathogenic fungus Fusarium oxysporum at a concentration of 500 µg/well Similarly, insect toxicity bioassays of GgChi (50 µg) against nymphs of Bemisia tabaci showed 14% reduction in adult emergence and 14% increase in mortality rate in comparison to control values. The GgChi (1.5 mg) protein showed significant reduction in a population of flour beetle (Tribolium castaneum) after 35 days, but lower reactivity against rice weevil (Sitophilus oryzae). The results of this study provide detai.led insight on functional characterization of a family 18 class III acidic plant endochitinase.

Correction: Ionotropic Chemosensory Receptors Mediate the Taste and Smell of Polyamines.

[This corrects the article DOI: 10.1371/journal.pbio.1002454.].

Inhibition of oxidative stress in cholinergic projection neurons fully rescues aging-associated olfactory circuit degeneration in Drosophila.

Loss of the sense of smell is among the first signs of natural aging and neurodegenerative diseases such as Alzheimer's and Parkinson's. Cellular and molecular mechanisms promoting this smell loss are not understood. Here, we show that Drosophila melanogaster also loses olfaction before vision with age. Within the olfactory circuit, cholinergic projection neurons show a reduced odor response accompanied by a defect in axonal integrity and reduction in synaptic marker proteins. Using behavioral functional screening, we pinpoint that expression of the mitochondrial reactive oxygen scavenger SOD2 in cholinergic projection neurons is necessary and sufficient to prevent smell degeneration in aging flies. Together, our data suggest that oxidative stress induced axonal degeneration in a single class of neurons drives the functional decline of an entire neural network and the behavior it controls. Given the important role of the cholinergic system in neurodegeneration, the fly olfactory system could be a useful model for the identification of drug targets.

Elimination of a ligand gating site generates a supersensitive olfactory receptor.

Olfaction poses one of the most complex ligand-receptor matching problems in biology due to the unparalleled multitude of odor molecules facing a large number of cognate olfactory receptors. We have recently deorphanized an olfactory receptor, TAAR13c, as a specific receptor for the death-associated odor cadaverine. Here we have modeled the cadaverine/TAAR13c interaction, exchanged predicted binding residues by site-directed mutagenesis, and measured the activity of the mutant receptors. Unexpectedly we observed a binding site for cadaverine at the external surface of the receptor, in addition to an internal binding site, whose mutation resulted in complete loss of activity. In stark contrast, elimination of the external binding site generated supersensitive receptors. Modeling suggests this site to act as a gate, limiting access of the ligand to the internal binding site and thereby downregulating the affinity of the native receptor. This constitutes a novel mechanism to fine-tune physiological sensitivity to socially relevant odors.

Ionotropic Chemosensory Receptors Mediate the Taste and Smell of Polyamines.

The ability to find and consume nutrient-rich diets for successful reproduction and survival is fundamental to animal life. Among the nutrients important for all animals are polyamines, a class of pungent smelling compounds required in numerous cellular and organismic processes. Polyamine deficiency or excess has detrimental effects on health, cognitive function, reproduction, and lifespan. Here, we show that a diet high in polyamine is beneficial and increases reproductive success of flies, and we unravel the sensory mechanisms that attract Drosophila to polyamine-rich food and egg-laying substrates. Using a combination of behavioral genetics and in vivo calcium imaging, we demonstrate that Drosophila uses multisensory detection to find and evaluate polyamines present in overripe and fermenting fruit, their favored feeding and egg-laying substrate. In the olfactory system, two coexpressed ionotropic receptors (IRs), IR76b and IR41a, mediate the long-range attraction to the odor. In the gustatory system, multimodal taste sensation by IR76b receptor and GR66a bitter receptor neurons is used to evaluate quality and valence of the polyamine providing a mechanism for the fly's high attraction to polyamine-rich and sweet decaying fruit. Given their universal and highly conserved biological roles, we propose that the ability to evaluate food for polyamine content may impact health and reproductive success also of other animals including humans.

Neuropeptides Modulate Female Chemosensory Processing upon Mating in Drosophila.

A female's reproductive state influences her perception of odors and tastes along with her changed behavioral state and physiological needs. The mechanism that modulates chemosensory processing, however, remains largely elusive. Using Drosophila, we have identified a behavioral, neuronal, and genetic mechanism that adapts the senses of smell and taste, the major modalities for food quality perception, to the physiological needs of a gravid female. Pungent smelling polyamines, such as putrescine and spermidine, are essential for cell proliferation, reproduction, and embryonic development in all animals. A polyamine-rich diet increases reproductive success in many species, including flies. Using a combination of behavioral analysis and in vivo physiology, we show that polyamine attraction is modulated in gravid females through a G-protein coupled receptor, the sex peptide receptor (SPR), and its neuropeptide ligands, MIPs (myoinhibitory peptides), which act directly in the polyamine-detecting olfactory and taste neurons. This modulation is triggered by an increase of SPR expression in chemosensory neurons, which is sufficient to convert virgin to mated female olfactory choice behavior. Together, our data show that neuropeptide-mediated modulation of peripheral chemosensory neurons increases a gravid female's preference for important nutrients, thereby ensuring optimal conditions for her growing progeny.

MOLECULAR MODEL OF CYTOTOXIN-1 FROM NAJA MOSSAMBICA MOSSAMBICA VENOM IN COMPLEX WITH CHYMOTRYPSIN.

Snake venom is a myriad of biologically active proteins and peptides. Three finger toxins are highly conserved in their molecular structure, but interestingly possess diverse biological functions. During the course of evolution the introduction of subtle mutations in loop regions and slight variations in the three dimensional structure, has resulted in their functional versatility. Cytotoxin-1 (UniProt ID: P01467), isolated from Naja mossambica mossambica, showed the potential to inhibit chymotrypsin and the chymotryptic activity of the 20S proteasome. In the present work we describe a molecular model of cytotoxin-1 in complex with chymotrypsin, prepared by the online server ClusPro. Analysis of the molecular model shows that Cytotoxin-1 (P01467) binds to chymotrypsin through its loop I located near the N-terminus. The concave side of loop I of the toxin fits well in the substrate binding pocket of the protease. We propose Phe10 as the dedicated P1 site of the ligand. Being a potent inhibitor of the 20S proteasome, cytotoxin-1 (P01467) can serve as a potential antitumor agent. Already snake venom cytotoxins have been investigated for their ability as an anticancer agent. The molecular model of cytotoxin-1 in complex with chymotrypsin provides important information towards understanding the complex formation.