Evaluation of recombinant Babesia gibsoni thrombospondin-related adhesive protein (BgTRAP) for the sero-diagnosis of canine babesiosis

Canine babesiosis, caused by Babesia gibsoni is one of the most significant tick-borne illnesses across the world. Light microscopy as well as polymerase chain reaction may fail in the diagnosis of disease when the level of parasitaemia is very low during subclinical and chronic cases. The serological techniques using a recombinant protein will be useful for the accurate and sensitive surveillance of the disease, especially in chronic cases. The present study describes the evaluation of recombinant N-terminal B. gibsoni Thrombospondin-related adhesive protein (BgTRAP) based indirect ELISA for the sero-diagnosis of B. gibsoni infection in dogs. A partial N-terminal BgTRAP gene (870 bp) of B. gibsoni, was expressed in Escherichia coli using a pET32a (+) vector. The recombinant BgTRAP based indirect ELISA was compared with the PCR targeting the same gene. A sensitivity and a specificity of 84% and 73.33% were observed in the indirect ELISA. The accuracy, positive predictive value and negative predictive value were 78.18%, 72.30%, 84.60% respectively. The rBgTRAP antigen did not show any cross-reactivity with sera from dogs infected with common helminth parasites viz. Ancylostoma caninum, Dirofilaria immitis, D. repens, Spirometra spp., Toxocara canis and haemoparasites like Trypanosoma evansi, Babesia vogeli, Hepatozoon canis and Ehrlichia canis.

Phylogenetic analysis of Babesia gibsoni isolates of south India using apical membrane antigen, 50 kDa surface antigen, and 70 kDa heat shock protein genes

The prevalence of canine babesiosis due to Babesia gibsoni has increased throughout the world including in southern India. The polymerase chain reaction (PCR) based molecular characterization of B. gibsoni in dogs of Kerala, south India, targeting three specific genes viz., apical membrane antigen (AMA1), 50 kDa surface antigen (P50), and heat shock protein (HSP70) was undertaken in this study. Out of 297 blood samples collected from clinically suspected animals, microscopy detected piroplasms of B. gibsoni in 60 (20.20 per cent), while the PCR targeting the BgP50 gene detected 85 (28.61 per cent). Polymerase chain reaction targeting the BgAMA1 and BgHSP70 detected a lesser number of samples (60 and 65 respectively) as positive. The phylogenetic analysis of BgHSP70 gene sequences did not reveal genetic heterogeneity among the B. gibsoni isolates of South India and from other countries, while the BgP50 gene differentiated the Indian isolates from Japanese isolates. When BgAMA1 was used for phylogenetic analysis, genetic variation was not observed among Indian and Taiwanese isolates, however, differentiated them from the Japanese isolates.

Transovarial transmission of pathogenic protozoa and rickettsial organisms in ticks

Transovarial transmission (TOT) is an efficient vertical transmission of pathogens that is observed in many arthropod vectors. This method seems to be an evolutionarily unique development observed only in Babesia sensu stricto (clade VI) and Rickettsia spp., whereas transstadial transmission is the common/default way of transmission. Transovarial transmission does not necessarily contribute to the amplification of tick-borne pathogens but does contribute to the maintenance of disease in the environment. This review aims to provide an updated summary of previous reports on TOT of tick-borne pathogens.

Molecular detection of pathogens in the ova and unfed larvae of Rhipicephalus annulatus and Haemaphysalis bispinosa ticks infesting domestic cattle of south India

This study aimed to investigate the presence of pathogens in the engorged ticks infesting domestic cattle, their ova, and unfed larvae. The engorged female ticks infesting domestic cattle of Wayanad district of Kerala, south India were collected and kept for oviposition. The dead females after the complete oviposition, their egg masses, and unfed larvae were screened for the presence of various pathogens by specific PCRs. The presence of Babesia bigemina, Anaplasma marginale, A. phagocytophilum, and Rickettsia spp. similar to R. raoultii was confirmed in Rhipicephalus annulatus ticks, their egg masses, and unfed larvae. Theileria orientalis was detected in Rh. annulatus females, but not in their egg masses or progenies. The presence of A. phagocytophilum and Rickettsia spp. similar to R. raoultii was confirmed in Haemaphysalis bispinosa ticks, their egg masses, and unfed larvae too. The presence of coinfections of B. bigemina with A. phagocytophilum and A. marginale were detected in Rh. annulatus ticks and their progenies.

Prevalence of Anti-Toxocara canis Antibodies in Dogs Detected with Recombinant Cathepsin L-1 and TES-26 Antigens in Three States of India

PURPOSE

Toxocara canis is a common intestinal nematode parasite of dogs with recognized zoonotic potential in tropical countries. The purpose of this study was to determine the seroprevalence of anti-T. canis antibodies in two target dog populations: household and community-owned, distributed over three distinct geographical regions of India.

METHODS

Two recombinant proteins of T. canis, cathepsin L-1 (CL-1) and Toxocara excretory-secretory-26 (TES-26), expressed in Escherichia coli, were used for studying the prevalence of anti-T. canis antibodies in dog populations in three distinct geographical regions of the country using an IgG-enzyme-linked immunosorbent assay. A total of 615 sera, 507 from household and 108 from community owned dogs were screened for IgG antibodies.

RESULTS

ELISA with recombinant (r) CL-1 showed 37.7% and 53.7% seroreactivity in household and community owned dogs, respectively. However, the rTES-26 antigen showed higher seroreactivity of 39.6% and 87.9% in the corresponding groups of household and community owned dogs, respectively. Chi-squared analysis of the data indicated that there was not any association in the prevalence of anti-T. canis antibodies between the samples analyzed from the three regions and the two cohorts of dog groups. However, the seroprevalence was higher in community owned dogs compared to household owned dogs.

CONCLUSION

The results of the serological evaluation suggest that both the groups of dogs show high seroreactivity rates and are likely to harbor T. canis infections of tissue dwelling dormant larvae.

Continued Mentorship Program for MBBS Students during COVID-19 Pandemic in Virtual Mode: A Questionnaire-based Observational Study

Introduction: The Coronavirus Disease-2019 (COVID-19) pandemic situation propelled the regular student mentorship program onto a virtual mode. Various surveys and studies have uncovered the ramifications on mental health and academic upheaval caused by the changing academic regulations and protocols. Aim: To evaluate the perception of mentors and mentees regarding the utility of virtual mentorship and to deduce barriers in continuing virtual mode mentorship program for 1st-year medical students. Materials and Methods: The present observational study was conducted at Sri Siddhartha Institute of Medical Sciences and Research Centre, from April-June 2020. A feedback form was administered to all participants after two months of the online mentorship program, via a semistructured questionnaire. The questionnaire had four open and eight close-ended responses for mentees. The contents were related to the frequency of meetings, mode of communication, perceived barriers, and futility of course, along with one open and five close-ended responses for mentors on barriers to effective conduct and perceived level of the mentoring relationship forged with students. A total of 12 mentors and 125 students responded. Results: It was observed that 96% of mentees felt that the program helped to fight alienation and stay connected, 89.6% felt inspired to study and 83% felt oriented to the online teaching programs. Both 91.7% of mentors and 82.4% of mentees asked for better applications, connectivity, and network support. In fact, the major barrier to effective communication was quoted as being poor network connectivity and applications support (47%). A comparable trend was noted among both mentees and mentors with respect to the program being rated good and above (91.7% mentors and 85.6% mentees). Hence, in the observational study, via thematic analysis and content analysis of qualitative data, two points were observed-1. The virtual mentorship program helped mentees to get emotionally and academically connected, cleared their doubts, and helped to reduce stress. 2. Poor technical and connectivity support were deduced as major barriers to the successful conduct of virtual mentorship. Conclusion: A well-structured virtual mentorship program guides the mentors to effectively chaperone mentees through a stressful uninterrupted academic course period, enhance academic performances and help alleviate the feeling of alienation.

Sequence and phylogenetic analysis of the thrombospondin-related adhesive protein gene of Babesia gibsoni isolates in dogs in South India

Babesia gibsoni, the causative agent of canine piroplasmosis, is a tick-borne intraerythrocytic protozoan parasite predominantly reported in Asian countries. The present study aimed at genotypic characterization of B. gibsoni isolates prevalent in dogs in Kerala, a southern state of India. Blood samples were collected from 272 dogs in Kerala and B. gibsoni infection was detected by microscopy and polymerase chain reaction (PCR). Molecular confirmation of B. gibsoni parasites was carried out by 18S rRNA nested-PCR, followed by sequencing. Nested-PCR detected a higher percentage of dogs (40.44%) positive for B. gibsoni infection than microscopy where 15.81% dogs were detected positive for infection. Genetic characterization of B. gibsoni isolates (n = 11) prevalent in dogs in the state of Kerala was carried out by PCR amplification and sequencing of the 855 bp thrombospondin-related adhesive protein (TRAP) gene fragment. Phylogenetic analysis of the B. gibsoni TRAP (BgTRAP) gene revealed that B. gibsoni isolates from Kerala formed a distinct cluster with the isolates from north India and Bangladesh, away from other East Asian isolates. Nucleotide analysis of the tandem repeats of BgTRAP gene showed considerable genetic variation among Indian isolates that was shared by B. gibsoni isolates of Bangladesh but not by the isolates of East Asian countries. The results of the present study further confirmed that B. gibsoni parasites in a distinct genetic clade are endemic in dogs in India and Bangladesh. However, elaborate studies are required for better understanding of the genetic diversity of B. gibsoni.

Phylogenetic analysis of bovine Theileria spp. isolated in south India

The objective of the present study is to determine the phylogenetic position of the Theileria organisms in blood of cattle of southern India using molecular tools. Theileria annulata (Namakkal isolate, Tamil Nadu) and three Theileria field isolates (free of T. annulata) from Wayanad, Kerala (Wayanad 1, 2, 3) were used. The small subunit ribosomal RNA (SSU rRNA) and major piroplasm surface protein (MPSP) gene products were cloned, sequenced and the phylogenetic tree constructed. SSU rRNA gene of Wayanad 1 isolate (JQ706077) revealed maximum identity with Theileria velifera or Theileria cervi. The phylogenetic tree constructed based on SSU rRNA genes revealed that Wayanad 1 isolate belonged to a new type which share common ancestor with all the other theilerial species while Wayanad 2 and 3 isolates (JX294459, JX294460) were close to types A and C respectively. Based on MPSP gene sequences, Wayanad 2 and 3 (JQ706078, JX648208) isolates belonged to Type 1 and 3 (Chitose) respectively. When, the previously reported MPSP type 7 is also considered from the same study area, Theileria orientalis types 1, 3 and 7 are observed in south India. SSU rRNA sequence of South Indian T. annulata (JX294461) showed a maximum identity with Asian isolates while the Tams1 merozoite surface antigen (MSA) gene (JX648210) showed maximum identity with north Indian isolate.

Isolation and characterization of novel plant growth promoting Micrococcus sp NII-0909 and its interaction with cowpea

A phosphate-solubilizing bacterial strain NII-0909 isolated from the Western ghat forest soil in India was identified as Micrococcus sp on the basis of phenotypic characteristics, carbon source utilization pattern, fatty acid methyl esters analysis, and 16S rRNA gene sequence. The strain exhibited the plant growth-promoting attributes of phosphate solubilization, auxin production, 1-aminocyclopropane-1-carboxylate deaminase activity, and siderophore production. It was able to solubilize (122.4μg of Ca(3)PO(4) ml(-1)), and produce IAA (109μgml(-1)) at 30°C. P-solubilizing activity of the strain NII-0909 was associated with the release of organic acids and a drop in the pH of the NBRIP medium. HPLC analysis detected two organic acids in the course of P-solubilization. A significant increase in the growth of cow pea was recorded for inoculations under controlled conditions. Scanning electron microscopic study revealed the root colonization of strain on cow pea seedlings. These results demonstrate that isolates NII-0909 has the promising PGPR attributes to be develop as a biofertilizer to enhance soil fertility and promote the plant growth.

Isolation and characterization of plant growth-promoting strain Pantoea NII-186. From Western Ghat forest soil, India

AIMS

To isolate plant growth-promoting bacterium from Western Ghat forests in India.

METHODS AND RESULTS

A Gram-negative, rod shaped, cream white coloured strain Pantoea NII-186 isolated from Western Ghat soil sample. The taxonomic position of the bacterium was confirmed by sequencing of 16S rRNA and phylogenetic analysis. A strain grew at a wide range of temperature ranging from 5-40 degrees C, but optimum growth was observed at 28-30 degrees C. It showed multiple plant growth-promoting attributes such as phosphate solubilization activity, indole acetic acid (IAA) production, siderophore production and HCN production. It was able to solubilize (28 microg of Ca(3)PO(4) ml(-1) day(-1)), and produce IAA (59 microg) at 28 degrees C. The solubilization of insoluble phosphate was associates with a drop in the pH of the culture medium. Pantoea sp. NII-186 tolerate to different environmental stresses like 5-40 degrees C, 0-7% salt concentration and 4-12 pH range.

CONCLUSIONS

The 16S rRNA gene sequence confirmed that the isolate NII-186 was belongs to Pantoea genus and showed considerable differences in physiological properties with previously reported species of this genus. Isolate NII-186 possessed multiple attributes of plant growth-promoting activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Hence in the context it is proposed that Pantoea sp. NII-186, could be deployed as an inoculant to attain the desired plant growth-promoting activity in agricultural environment.