Author Correction: Buffalo nasal odorant-binding protein (bunOBP) and its structural evaluation with putative pheromones.

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Buffalo nasal odorant-binding protein (bunOBP) and its structural evaluation with putative pheromones.

Pheromones are odoriferous volatile chemical cues produced by animals for communication among conspecifics so as to regulate their social behaviors. In general, the odor compounds are recognized by receptors in the nasal cavity. Odorant-binding protein (OBP), a lipocalin family protein, mediates the air-borne odor cues to nasal receptors through nasal mucus. The presence of OBP in several mammalian species is well documented but to-date there is no report of a nasal OBP in buffalo. Hence, the present study was undertaken to investigate if OBP is present in buffalo nasal mucus. Uni- and two-dimensional gel electrophoresis of the nasal mucus suggested the presence of OBP, which was confirmed using mass spectrometry. In silico homology model of the OBP was generated and its structural similarity with other mammalian OBPs was assessed. Finally, molecular-docking and -dynamics simulations analysis revealed the efficiency of buffalo nasal OBP (bunOBP) to bind with buffalo pheromones as well as other reported chemical cues. Taken together, the occurrence of nasal OBP in buffalo and its putative role in odor binding are reported for the first time. The potential association of this protein with estrus-specific volatiles could be taken to advantage for non-invasive detection of estrus in buffaloes.

A combinatorial model for effective estrus detection in Murrah buffalo.

BACKGROUND: Buffaloes are silent heat animals and lacunae in their estrus detection results a substantial economic loss in developing countries. Many advanced tools to aid heat detection have been developed but are neither affordable nor easily interpretable by marginal farmers. AIM: The present investigation was made to develop a cost-effective estrus detection model by combining several known estrus predicting parameters. MATERIALS AND METHODS: Various signs of estrus were classified under major parameters such as visual, cow behavioral, bull behavioral, biochemical, and gyneco-clinical. Expression of those parameters was observed in buffaloes, and the percentage of positive estrus detection was calculated for each combination of estrus prediction parameters. RESULTS: The present result concludes that the model comprises of five parameters group with several signals with twenty-six different combinations. It was observed that the expression of individual combinations and their corresponding estrus detection efficiency varies significantly, i.e., detection efficiency rises as the number of combination increases. CONCLUSION: Combination of three parameters would provide an estrus detection efficiency >70% and suggested for an easy estrus detection. This would be a cost-effective model for farmers and benefits in enhancing buffalo population/reproduction.

Exploration of Luteinizing hormone in murrah buffalo (Bubalus bubalis) urine: Extended surge window opens door for estrus prediction.

Estrus detection in buffaloes has been a major concern for decades, and lack of reliable methods affects their effective reproductive management. Luteinizing hormone (LH) detection in urine is in practice for several mammals for timed insemination, whereas very few reports are available on buffalo urinary LH. The focus of this study is to detect the presence of LH in buffalo urine, quantitate variation in urinary LH during different estrous cycle phases and examine the duration of mid-cycle LH window. Nearly hundred buffaloes were examined, longitudinal urine samples (n=42) were collected from seventeen animals and classified into respective phases based on several estrus detection parameters. The urinary LH was detected using bovine LH ELISA kit validated for serum/plasma/tissue homogenate. Detection of buffalo LH in the neat urine convincingly proved the competence of the bovine LH kit. Variation in the LH range was observed between different phases of estrous cycle and significant fold variation (P<0.05) was noticed during estrus phase (1.01±0.23) with average baseline value of 46.73±3.36mIU/mL. Interestingly, an extended window (A1-A3) of mid-cycle LH surge was observed due to its lingering excretion in urine. The results, altogether, revealed that LH can be detected in buffalo urine with noticeable fold variation during estrus phase and the extended LH window intensifies the chance of ovulation prediction for timed insemination.

Exoproteome of Aspergillus flavus corneal isolates and saprophytes: identification of proteoforms of an oversecreted alkaline protease.

Aspergillus flavus infects the human eye leading to keratitis. Extracellular proteins, the earliest proteins that come in contact with the host and virulence related exoproteins, were identified in the fungus isolated from infected cornea. Virulence of the corneal isolates was tested in the Galleria mellonella larvae model and those isolates showing higher virulence were taken for subsequent exoproteome analysis. High resolution two-dimensional electrophoresis and mass spectrometry were used to generate A. flavus exoproteome reference map as well as to profile most of the exoproteins. Analysis of the identified proteins clearly shows the major biological processes that they are involved in. Nearly 50% of the exoproteins possess catalytic activity and one of these, an alkaline serine protease (Alp1) is present in high abundance as well as multiple proteoforms. Many proteins in the A. flavus exoproteome have been shown to be virulence factors in other pathogens indicating the probable role for these proteins in the corneal infection as well. Interestingly, the majority of the exoproteins do not have secretory signal indicating that they are secreted through the non-classical pathway. Thus, this study provides a clue to the early strategies employed by the pathogen to establish an infection in an immunocompetent host. BIOLOGICAL SIGNIFICANCE: The outcome of a fungal infection in an immunocompetent human eye depends on the ability of the fungus to overcome the host defense and propagate itself. In this process, the earliest events with respect to the fungal proteins involved include the secretory proteins of the invading organism. As a first step towards understanding the role of the extracellular proteins, exoproteome profile of the fungal isolates was generated. The fungal isolates from cornea showed a distinct pattern of the exoproteome when compared to the saprophyte. Since corneal isolates also showed higher virulence in the insect larval model, presumably the proteins elaborated by the corneal isolates are virulence related. One of the abundant proteins is an alkaline serine protease and this protein exists as multiple proteoforms. This study reports the comprehensive profile of exoproteome and reveals proteins that are potential virulence factors.