Petroleum ether, chloroform (CHCl3) and methanol (CH3OH) extracts of the flowers and leaves of Caesalpinia pulcherrima (L.) were evaluated for their larvicidal activity against Culex quinquefasciatus Say and their repellent activity against three stored grain pests: Tribolium castaneum (Hbst.), Sitophilus oryzae (L.) and Callosobruchus chinensis (L.). The LC50 values ​​of the petroleum ether and CHCl3 extracts of the flowers were 119.80, 37.34, 25.06, 17.12, and 10.36 ppm and 101.04, 76.67, 66.67, 58.24, and 51.82 ppm, respectively, after 24, 30, 36, 42, and 48 h of exposure. The CHCl3 leaf extract showed LC50 values ​​of 361.21, 321.10, 245.41, 207.09, and 203.19 ppm after 24, 30, 36, 42, and 48 h of exposure, respectively. Depending on the intensity of larvicidal activity on the mosquito, the extracts can be classified in descending order as follows: petroleum ether (flower) >CHCl3 (flower) >CHCl3 (leaf). Extracts of flowers with petroleum ether demonstrated a highly significant repellent effect against adult T. castaneum (p<0.01), extracts of leaves with CHCl3 and CH3OH showed a moderately significant repulsion against adult T. castaneum (p<0.05), and extracts of leaves with petroleum ether also showed a moderately significant repulsion against adult S. oryzae (p<0.05). J. Bio-Sci. 33(2): 77-86, 2025

Understanding the bacteria found in fishponds is essential for fish health management and disease prevention, especially given the increasing public health risks associated with antibiotic resistance in aquatic ecosystems. In this study, the multidrug resistance profile of bacteria in fishpond water was examined, and identification of bacteria was conducted using 16S rRNA sequencing method. The study revealed a worrying trend of antibiotic resistance in bacteria isolated from various fishponds in Rajshahi District, Bangladesh. All the antibiotics tested showed significant resistance, with sulfadiazine-trimethoprim being the highest (86.61%) and ciprofloxacin the lowest (49.187%). Alarmingly, nearly 38.09% of the bacteria were resistant to all the antibiotics tested. The present study identified a diverse bacterial community composed of 37 distinct bacterial strains belonging to 16 different genera. Enterobacter emerged as the most abundant genus, followed by Klebsiella, Bacillus, Escherichia, Acinetobacter, Shigella and among others. These dominant bacteria genera also demonstrated a high degree of resistance to the antibiotics tested in this study. In addition, the majority of the bacterial isolates identified are known to be pathogenic. The increase in multidrug-resistant bacteria (MRB) in fishponds poses a significant threat to aquatic organisms and human health, as infections can spread through contaminated fish or through direct contact with pond water. This emphasizes the need for judicious use of antibiotics in aquaculture to limit resistance development and its transmission through the food chain. J. Bio-Sci. 33(1): 67-78, 2025

Petroleum ether (PE), chloroform (CHCl3), and methanol (CH3OH) extracts of the whole Cassia tora Linn. plant were evaluated by dose-mortality tests and for their repellent activity against Callosobruchus chinensis L., Sitophilus oryzae L., and Tribolium castaneum (Hbst.), their cytotoxicity against Artemia salina L. nauplii, their larvicidal activity against Culex quinquefasciatus Say larvae, and their piscicidal activity against the fish Poecilia reticulata Peters, under laboratory conditions. In the dose-mortality test, the PE and CH3OH extracts of the tested plant showed favorable results against C. chinensis, the PE extract was the most active with an LD50 of 1.51 mg/cm² after 48 h of exposure. Against S. oryzae, the PE extract showed the highest activity with an LD50 of 0.62 mg/cm² after 48 h of exposure. And against T. castaneum, only the PE and CH3OH extracts of the tested plant caused mortality, while the PE extract was more active with an LD50 of 0.82 mg/cm² after 48 h of exposure. However, the C. tora extract with CHCl3 induced no mortality in C. chinensis or T. castaneum. In the repellent test, with the exception of the PE and CHCl3 extracts against T. castaneum, all extracts showed significant repellent activity against C. chinensis, S. oryzae, and T. castaneum. Regarding the cytotoxicity test, all C. tora extracts reacted against A. salina nauplii, with the PE extract proving the most effective, with a minimum LC50 of 33.54 ppm after 48 h of exposure. Against C. quinquefasciatus larvae, the CHCl3 extract exhibited the highest larvicidal activity, with an LC50 of 60.93 ppm after 48 h of exposure. During the piscicidal activity test, only the CH3OH extracts of the tested plant showed promising results against the fish P. reticulata, with an LC50 of 28.85 ppm after 48 h of exposure. In contrast, the PE and CHCl3 extracts of C. tora were not lethal to P. reticulata. J. Bio-Sci. 33(1): 101-112, 2025

Aerides crispa Lindl., an epiphytic orchid native to the Western Ghats of India, holds significant ornamental and medicinal values. Unfortunately, several orchid species are recognized as threatened due to habitation loss and lack of inefficient natural propagation. This study aimed to develop a reliable and reproducible in vitro regeneration protocol for A. crispa through asymbiotic seed germination and tissue culture techniques. Green, un-dehisced seedpods harvested 60-63 days after pollination were surface sterilized and inoculated on Murashige and Skoog medium. The highest seed germination (91.67%) occurred on hormone-free MS medium, indicating that exogenous plant growth regulators are not essential for germination. However, 1.0 µM/L BAP significantly enhanced protocorm-like body (PLB) formation (93.33%) and shoot development (90%). Optimal microshoot multiplication (15.52 ± 0.17 shoots/explant) was achieved with 2.0 µM/L BAP + 1.0 µM/L IBA, while maximum shoot elongation occurred at 1.0 µM/L BAP. Rooting was most effective with 4.0 µM/L IBA, producing 93.33% rooting and an average of 4.21 roots/shoot. Among acclimatization substrates, the mixture of garden soil, cocopeat, and charcoal (1:1:1) supported 100% in vivo survival. This study provides a suitable plant propagation approach that might be useful for the conservation of A. crispa, thereby contributing to ex situ conservation of the threatened orchid species and their further commercial cultivation. J. Bio-Sci. 33(1): 79-92, 2025

The present study focuses on the asymbiotic germination of seeds through in vitro culture of Eria lasiopetala, a native medicinal orchid in Bangladesh. Out of the four basal media, MS was found to be the most effective medium, where 93.58±0.374% seed germinations were recorded. Different plant growth regulators (PGRs), e.g. BAP, Kin, NAA and were used for secondary protocorm proliferation, plantlet development, and multiplication of shoot buds through in vitro conditions. The maximum number of secondary protocorms (12.80±0.115) were developed that were derived from primary protocorms on MS medium fortified with 0.5 mg/l BAP and 1.0 mg/l NAA. Data revealed that 0.5 mg/l BAP + 0.25 mg/l NAA showed the best combination for height elongation of plantlets (3.12±0.012 cm) in MS medium. While for multiple shoot buds (MSBs) 1.0 mg/l BAP + 0.5 mg/l NAA showed better (6.8±0.127) performance than other combinations of PGRs. The single shoots were isolated from the multiple shoots and sub-cultured on ½MS medium supplemented with NAA (0.5 - 2.0 mg/l), IAA (0.5 - 2.0 mg/l) and IBA (0.5 - 2.0 mg/l) for root induction. The maximum number of roots (7.53±0.176) and its growth (4.61±0.01 cm) were found in ½MS medium supplemented with 1.0 mg/l IAA. The well rooted plantlets were hardened and successfully transferred after acclimatization in pots containing the mixture of coconut husk, charcoal and brick pieces in the ratio of 2:1:1 and eventually established under natural condition. J. Bio-Sci. 32(1): 45-60, 2024

Pneumonia is an infectious disease of the respiratory tract that causes inflammation of the pulmonary parenchyma. The study aimed to determine the relationship between bacterial pneumonia and chronic periodontitis. This was a cross sectional type of descriptive study which was carried out among the 104 patients attending at Dental Outpatient Department, Barind Medical College Hospital, Rajshahi for the treatment of chronic periodontitis which were selected purposely. Most responders (46.2%) were between the ages of 21 and 30, and the vast majorities (88.5%) were men. Data showed that 92.0% of people came from a nuclear family, 63.5% had completed high school, and 70.2% had a monthly house hold income of less than 10,000 Taka. Great majority (46.2%) lived in standard housing without windows (52.9%) or ventilation (66.0%). With regards to the evaluation of chronic periodontal condition, 87.5% of those with community acquired pneumonia had history of gum bleeding, compared to 95.2% of those with no history of this. Most cases of pneumonia were identified as being caused by Streptococcus pneumonia (59.80%) after bacteriological testing. One-way analysis of variance revealed a significant correlation (p<0.001) between oral hygiene index, dental calculus index and dental periodontal index and bacterial pneumonia. Bacterial pneumonia was found to be substantially linked with housing condition, ventilation, sunlight and oral hygiene index (p<0.05). People would not get bacterial pneumonia if we told them to take care of their gums and teeth, patients who had received periodontal therapy and practiced good oral hygiene were found to have a risk of pneumonia that was nearly half that of the general population. J. Bio-Sci. 32(1): 21-29, 2024

Lathyrus sativus L. causes lathyrism both in animals and human due to the presence of the neurotoxin β-ODAP (β -N-Oxalyl-L-α, β -diaminopropionic acid). This study was performed to find out the toxic effect of grass pea on onion root tip cells. The root lengths of onion were reduced as the concentrations of different plant parts extracts of grass pea increased. The percentages of chromosomal abnormalities, NV and ICV of onion root tip cells showed an increasing trend with the increasing of different extracts concentrations. The mitotic index and chromosomal abnormalities in treated onion root tip cells were significantly different than that of control. The mitotic index and chromosomal abnormalities had a reverse relationship. Almost all the treated root tip cells of onion showed this mito-depressive effect. From this findings, it may concluded that β -N-Oxayl-L- α, β-diaminopropionic acid (Lathyrogens) in Lathyrus sativus may be responsible for mitotic depression and chromosomal abnormalities on the root tip cells of onion. J. Bio-Sci. 31(1): 51-60, 2023

Prostate-Specific Antigen (PSA) is a prostate cancer tumor marker, but furthermore, studies have revealed that many people with benign prostatic issues or other conditions have high PSA levels in their blood. As a result, various approaches have been suggested to boost prostate-specific antigen specificity. The aim of the study to determine whether the free-to-total PSA ratio (percent fPSA) is able to be utilized to discriminate between prostate cancer and benign prostatic hyperplasia. From December 2018 to November 2022, 260 males with Lower Urinary Tract Symptoms (LUTS) symptoms attended Rajshahi Medical College Hospital in Bangladesh were recruited purposively for a cross sectional study as per inclusion criteria. Digital Rectal Examination (DRE) and transrectal ultrasonography were performed along with age analysis. Before any manipulation, total PSA, free PSA, and percent free PSA were assessed. Transrectal ultrasound-guided biopsy or digitally guided biopsy was used to confirm the diagnosis. SPSS 26 was used to analyze the data. Among the 260 individuals, 105 were diagnosed with prostate cancer and the remaining 155 were diagnosed with benign prostatic hyperplasia. Patients with CaP were much older than those with Benign Prostatic Hyperplasia (BPH) (Mean±SD was 72±4.4 vs. 64±6.6 years, respectively) (p = 0.00001). The sensitivity, specificity, and positive predictive value of % free PSA (at cut off point 0.16) were greater (94%, 93%, 90% respectively) than those of total PSA (84%, 48%, 52% respectively). The proportion of false positives was lower in percent free PSA (10%) than in tPSA (19%). All of these considerations are critical in establishing the appropriateness of a screening test. In case of percent free PSA, the overall accuracy was 93%, significantly higher than tPSA (62%) (p<0.005). Thus, the free/total/ serum PSA ratio assists more accurately in differentiating BPH from prostate cancer. When compared to tPSA, the fPSA/tPSA and ratio enhance the discrimination between BPH and CaP comparable and are equally beneficial in lowering the incidence of unnecessary biopsies, but tPSA alone has less impact. J. Bio-Sci. 30(2): 67-77, 2022

Petroleum ether (PE), chloroform (CHCl3), and methanol (CH3OH) extracts of the whole chickpea plant Cicer arietinum (L.) have been tested against adult beetles of Callosobruchus chinensis (L.), Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) through dose-mortality and repellent activity tests. In dose mortality tests, the PE extracts of C. arietinum gave LD50 values of 3.466, 3.292, 2.721, 2.398, 1.887, 1.663 and 1.428 mg/cm2 against C. chinensis and 4.297, 3.415, 2.246, 1.725, 1.384, 0.984 and 0.722 mg/cm2 against S. oryzae both after 12, 18, 24, 30, 36, 42 and 48 h of exposures, respectively. The CHCl3 extracts gave LD50 values of 5.242, 4.844, 3.472, 2.945, 2.540, 1.875, 1.295 and 1.053 mg/cm2 against C. chinensis after 6, 12, 18, 24, 30, 36, 42 and 48 h of exposures, respectively. The CH3OH extracts, on the other hand, yielded LD50 values of 0.923, 0.757, 0.649, 0.515, 0.400, 0.303, 0.247 and 0.197 mg/cm2 against C. chinensis, 4.227, 3.528, 3.454, 2.933, 2.493, 2.187, 1.938 and 1.724 mg/cm2 against S. oryzae and 3.485, 3.176, 2.851, 1.531, 1.113, 0.756, 0.534 and 0.478 mg/cm2 against T. castaneum adults after 6, 12, 18, 24, 30, 36, 42 and 48 h of exposures, respectively. However, the PE extracts of C. arietinum did not show any mortality against T. castaneum and the CHCl3 extracts were inactive against S. oryzae and T. castaneum adults. In repellency tests, all three organic extracts did not show any repellency against the test beetles. According to their intensity of activities, the extracts could be arranged in the following descending order: CH3OH extracts against C. chinensis > CH3OH extracts against T. castaneum > PE extracts against S. oryzae > CHCl3 extracts against C. chinensis > PE extracts against C. chinensis > CH3OH extracts against S. oryzae adults. The present results indicate that the test plant C. arietinum contains bioactive compounds and could be used as a source of control agents for the stored product pests. J Bio-Sci. 30(1): 91-100, 2022 (June)

Milk contains many nutrients including carbohydrate, protein, fat, vitamins and minerals. Milk protein has high nutritional value because it contains all the essential amino acids. Considering the nutritive value, milk is widely consumed by the people as an ideal food. The biochemical changes in milk and milk products by microorganisms can be either desirable or undesirable. The safety of milk and milk products with respect to food borne diseases is of great concern around the world. Therefore, the present study was undertaken to determine the prevalence of Escherichia coli in milk and milk product with their antibiogram assay. A total of 150 milk and milk product (yogurt) samples were collected from Rajshahi Metropolitan area of Bangladesh and analyzed by cultural, staining and biochemical tests for the isolation and identification of E. coli. Antibiogram assay of all the isolates were done by disk diffusion method. The overall prevalence of E. coli was 20.0% in milk and milk product (yogurt) in Rajshahi Metropolitan area. The prevalence of E. coli was 26.0% and 34.0% in raw milk and in milk product (yogurt), respectively. E. coli was not detected in pasteurized milk in this study. In antibiogram assay, isolated E. coli showed 100.0%, 60.0%, 40.0%, 40.0%, 33.3%, 33.3%, 20.0%, and 10.0% resistance to penicillin, gentamycin, ampicillin, streptomycin, amoxycillin, sulfamethoxasole-trimethoprim, nalidixic acid, and ciprofloxacin, respectively. The isolates also showed 73.3%, 60.0%, 53.3%, 53.3%, 30.0%, 23.3%, and 20% sensitive to ciprofloxacin, nalidixic acid, sulfamethoxasole-trimethoprim, streptomycin, amoxycillin, ampicillin, and gentamycin, respectively. The findings of this experiment speculated that the use of ciprofloxacin and nalidixic acid may have the preference in the clinical control of milk borne E. coli infection in Bangladesh. J. Bio-Sci. 29(2): 81-91, 2021 (December)