Moizur Rahman

Antibacterial, antifungal and cytotoxic activities of amblyone isolated from Amorphophallus campanulatus.

Objective: To assess the in vitro antibacterial, antifungal and cytotoxic activities of amblyone, a triterpenoid isolated from Amorphophallus campanulatus (Roxb). Methods: Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Cytotoxicity was determined against brine shrimp nauplii. In addition, minimum inhibitory concentration (MIC) was determined using serial dilution technique to determine the antibacterial potency. Results: Large zones of inhibition were observed in disc diffusion antibacterial screening against four Gram-positive bacteria (Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus and Streptococcus pyogenes) and six Gram-negative bacteria (Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, Pseudomonas aeruginosa and Salmonella typhi). The MIC values against these bacteria ranged from 8 to 64 μg/ml. In antifungal screening, the compound showed small zones of inhibition against Aspergillus flavus, Aspergillus niger and Rhizopus aryzae. Candida albicans was resistant against the compound. In the cytotoxicity determination, LC50 of the compound against brine shrimp nauplii was 13.25 μg/ml. Conclusions: These results suggest that the compound has good antibacterial activity against the tested bacteria, moderate cytotoxicity against brine shrimp nauplii and insignificant antifungal activity against the tested fungi.

Age-Specificity of Toxoplasma gondii Seroprevalence in Sheep, Goats and Cattle on Subsistence Farms in Bangladesh

ABSTRACT Toxoplasma gondii is a zoonotic protozoan parasite that infects humans and domestic animals. In this study, the seroprevalence of T. gondii antibodies was investigated using serum samples collected from 83 sheep, 146 goats and 37 cattle from a dozen subsistence farms in Bangladesh. Fifty-eight out of 83 sheep (69.9%), 89 out of 146 goats (61.0%) and 10 out of 37 cattle (27.0%) were seropositive for the parasite. Seroprevalence in young goats (<1 year old) was significantly lower than that of the adult goats (>1 year old). In contrast, seroprevalence for young and adult sheep was similar. These results indicate that acquired infection with T. gondii occurs in this region of Bangladesh, at least among goats.

Antibacterial, antifungal and cytotoxic activities of salviasperanol isolated from Amorphophallus campanulatus

Salviasperanol, a diterpenoid isolated from Amorphophallus campanulatus (Roxb.) Bl. (Araceae) was studied for in vitro antibacterial, antifungal, and cytotoxic activities. The disc diffusion technique was used to determine in vitro antibacterial and antifungal activities. Cytotoxicity was determined against brine shrimp nauplii. In addition, minimal inhibitory concentration (MIC) was determined using serial dilution technique to determine antibacterial potency. The MIC values against these bacteria ranged from 8 to 64 μg/mL. The compound showed significant antibacterial activity against four Gram-positive bacteria (Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Streptococcus β-haemolyticus) and six Gram-negative bacteria (Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, Pseudomonus aeruginosa, Salmonella typhi). The compound showed weak antifungal activity against a number of fungi. In the cytotoxicity determination, the LC50 of the compound against brine shrimp nauplii was 8.02 μg/mL.

Prevalence and dynamics of antibodies against Toxoplasma gondii in kids born from naturally infected goats.

We investigated the presence of antibodies against Toxoplasma gondii in domesticated goats intended for human consumption in a rural suburb of Rajshahi, Bangladesh. Antibodies to T. gondii were found in 55.1% (80/145) of the goats tested in our sample. The seroprevalence among goats aged <1 year, 1-2 years, 2-3 years and ≥3 years were 36.7%, 66.0%, 59.1% and 100%, respectively. Our results demonstrated that seroprevalence increased with age. Among the seropositive goats, a subsample of eight free-ranging female goats with access to male goats was placed under continuous observation. During the observation period, these seropositive female goats delivered 11 kids, all of which were found to be seronegative before suckling colostrum. This finding strongly suggested that trans-placental infection rarely occurs in female goats that have acquired an infection before pregnancy. Our results indicate that infection via ingestion of oocysts plays a more important role than endogenous trans-placental infection in maintaining the endemicity of T. gondii among goats in Bangladesh.

Theileria annulata seroprevalence among different cattle breeds in Rajshahi Division, Bangladesh

An epidemiological survey of Theileria annulata infection was undertaken in a cattle population in Rajshahi Division, Bangladesh. The local cattle breeds from the area (North Bengal Gray and Deshi) and crosses between the local breeds and Holstein cattle were predominantly screened. In total, 192 cattle serum samples were collected in two areas of Rajshahi Division, the Rajshahi District (n=147) and Natore District (n=45). The samples were screened with an enzyme-linked immunosorbent assay using T. annulata surface protein (TaSP) as the antigen. The seroprevalence was 80.0% (36/45) in Natore and 20.4% (30/147) in Rajshahi. A logistic regression analysis showed that the sampling location was significantly associated with seropositivity, whereas age, sex and breed were not. Although the logistic regression analysis did not show a linear dependence on age, we considered age-specific seroprevalence separately in the two districts. Seroprevalence did not differ significantly among age categories in the Natore District. In contrast, all the cattle <1 year old in the Rajshahi District were seronegative (11/11). Seroprevalence in the 1- and 2-year-old cattle was significantly lower in the Rajshahi District than in the Natore District. In the older age categories (3, 4 and >5 years), seroprevalence did not differ significantly between the Natore and Rajshahi Districts. These results suggest that the cattle in the Rajshahi District were sporadically exposed to T. annulata, whereas most cattle in the Natore District became infected during an early phase of life.