Biology subjects

Yasmin, M.

Publications and source records attributed to Yasmin, M..

6 recordsLinked to original sources

bioRxiv2026

Comparative immunogenicity and protective efficacy of formaldehyde-inactivated whole-cell and sonicated whole-cell extract vaccines against multidrug-resistant Pseudomonas aeruginosa in mice

Background: Pseudomonas aeruginosa is a major opportunistic Gram-negative pathogen responsible for healthcare-associated infections, while increasing antimicrobial resistance has narrowed therapeutic options. Vaccine development therefore represents an important complementary strategy for prevention. This study compared the immunogenicity and protective efficacy of a formaldehyde-inactivated whole-cell vaccine with a sonicated whole cell extract preparation against multidrug-resistant (MDR) P. aeruginosa in mouse model. Methods: Clinical P. aeruginosa isolates were obtained from specimens collected at Dhaka Medical College Hospital between July 2022 and February 2026. Formaldehyde-inactivated whole-cell and sonicated whole cell extract preparations were produced from P. aeruginosa. A total of 144 female Swiss albino mice aged 6-8 weeks were used: 120 mice were allocated to two independent immunization experiments and 24 mice were used for LD50 determination. Mice received three intramuscular immunizations on days 0, 14, and 28. Antigen-specific serum IgG was assessed by enzyme-linked immunosorbent assay (ELISA), functional antibody activity was evaluated by serum bactericidal assay (SBA), and protective efficacy was assessed following lethal intraperitoneal challenge. Results: Ten isolates from MDR P. aeruginosa were selected by simple random sampling from the clinical isolates for vaccine preparation. The estimated protein concentration of the sonicated preparation was 1.872 mg/mL. Both vaccine groups developed significantly higher anti-P. aeruginosa IgG responses than the control group after immunization (p<0.001). Following lethal challenge, survival was 100% in mice receiving the formaldehyde-inactivated vaccine and 91.7% among mice receiving the sonicated preparation; no control mice survived. Between-vaccine differences in survival were not statistically significant. SBA demonstrated complement-dependent bactericidal activity in sera from both vaccinated groups, with activity detectable to a dilution of 1:32 for the whole-cell vaccine and 1:64 for the sonicated preparation. Conclusions: Both vaccine preparations elicited strong humoral responses and substantial protection against lethal MDR P. aeruginosa challenge in mice. The findings support further investigation of multicomponent P. aeruginosa vaccine strategies, although additional studies using multiple challenge strains and broader immunological endpoints are required before conclusions regarding translational efficacy can be drawn.

microbiology↗

bioRxiv2026

Genomic Insights into Multi-Drug-Resistant, Klebsiella pneumoniae Isolated from an Infertile Woman: A Comprehensive Analysis of Antibiotic Resistance and Virulence Factors

Objectives: Klebsiella pneumoniae is a significant global health concern due to its ability to cause diverse infections and its increasing multidrug resistance. This study analyzed the whole-genome sequence of multidrug-resistant K. pneumoniae strain CP4, isolated from a vaginal swab of an infertile woman, to characterize its virulence factors, antibiotic resistance mechanisms, and epidemiological features. Methods: The Kirby-Bauer disk diffusion assay was used to screen antibiotic resistance. Whole genome sequencing was conducted using the Illumina MiSeq platform and followed by comprehensive bioinformatic analysis. Results: Antibiotic susceptibility testing revealed that the K. pneumoniae strain CP4 exhibited resistance to 11 of 18 tested antibiotics, including carbapenems, and displayed a Multiple Antibiotic Resistance (MAR) index of 0.611. Whole-genome sequencing identified an array of putative virulence and metal-resistant genes, classifying it as a human pathogen with a probability score of 0.887. The strain was characterized as sequence type 327 with K16 capsular and O1/O2v1 somatic antigens. The antibiotic resistome included 38 putative genes conferring resistance to a spectrum of antibiotics. Moreover, point mutations were identified in several genes that ResFinder predicted to be associated with resistance to fluoroquinolones, cephalosporins, and carbapenems. Additionally, K. pneumoniae strain CP4 harbored six putative plasmid-replicon types and 454 putative mobile genetic element-associated protein hits among predicted ORFs. Several putative antibiotic resistance genes, including tet(A), floR, mph(A), and aph(6)-Id, were associated with insertion sequences, transposons, and integrons, indicating a potential for horizontal gene transfer. Conclusions: The genomic features of multidrug-resistant K. pneumoniae CP4 highlight its potential for antimicrobial resistance and virulence, emphasizing the need for continued genomic surveillance and targeted interventions. Keywords: Klebsiella pneumoniae, Whole Genome Sequencing, Antimicrobial Resistance, Pangenome analysis

microbiology↗

bioRxiv2024

The high-light-tolerant desert alga Chlorella ohadii is protected from oxidative stress by a non-photochemical quenching-independent mechanism

Non-photochemical quenching (NPQ) mechanisms are crucial for protecting photosynthesis from photoinhibition in plants, algae, and cyanobacteria, and their modulation is a long-standing goal for improving photosynthesis and crop yields. The current work demonstrates that Chlorella ohadii, a green micro-alga that thrives in the desert under high light intensities which are fatal to many photosynthetic organisms, does not perform nor require NPQ to protect photosynthesis under constant high light. Instead of dissipating excess energy, it minimizes its uptake by eliminating the photosynthetic antenna of photosystem II. In addition it accumulates antioxidants that neutralize harmful reactive oxygen species (ROS) and ramps up cyclic electron flow around PSI. These NPQ-independent responses proved efficient in preventing ROS accumulation and reducing oxidative damage to proteins in high-light-grown cells.

plant biology↗

bioRxiv2023

The protein phosphorylation landscape in photosystem I of the desert algae Chlorella sp.

O_LIThe phosphorylation of photosystem II (PSII) and its antenna (LHCII) proteins has been extensively studied and its involvement in state transitions and PSII repair is well known. Yet, very little is known about the extent and functions of phosphorylation of photosystem I (PSI) and its antenna (LHCI) proteins. C_LIO_LIHere, two proteomics methods were applied to generate a detailed map of the phosphorylation sites of the PSI-LHCI proteins in Chlorella ohadii cells that were grown under low- or extreme high-light intensities (LL and HL). Furthermore, we analyzed the content of oxidized tryptophans in these cell types to estimate light-induced oxidative damage to PSI-LHCI. C_LIO_LIOur work revealed the phosphorylation of 11 out of 22 PSI-LHCI subunits. The analyses detected extensive phosphorylation of the LHCI subunits lhca6 and lhca7. Other PSI-LHCI subunits were phosphorylated to a lesser extent. Additionally, we show the accumulation of oxidatively damaged tryptophans in the psaD subunit of PSI of HL-grown C. ohadii. C_LIO_LIThe significant phosphorylation of lhca6 and lhca7 suggests a physiological role during photosynthesis, possibly by altering light-harvesting characteristics and binding of other LHCI subunits. Moreover, we show that psaD is susceptible to photodamage while LHCI is protected from ROS under HL. C_LI

plant biology↗

bioRxiv2022

A desert green alga that thrives at extreme high-light intensities using a unique photoin-hibition protection mechanism

While light is the driving force of photosynthesis, excessive light can be harmful. Photoinhibition, or light-induced photo-damage, is one of the key processes limiting photosynthesis. When the absorbed light exceeds the amount that can be dissipated by photosynthetic electron flow and other processes, damaging radicals are formed that mostly inactivate photosystem II (PSII). A well-defined mechanism that protects the photosynthetic apparatus from photoinhibition has been described in the model green alga Chlamydomonas reinhardtii and plants. Chlorella oha-dii is a green micro-alga, isolated from biological desert soil crusts, that thrives under extreme high light (HL) in which other organisms do not survive. Here, we show that this alga evolved unique protection mechanisms distinct from those of C. reinhardtii and plants. When grown under extreme HL, significant structural changes were noted in the C. ohadii thylakoids, including a drastic reduction in the antennae and the formation of stripped core PSII, lacking its outer and inner antennae. This is accompanied by a massive accumulation of protective carotenoids and proteins that scavenge harmful radicals. At the same time, several elements central to photoinhibition protection in C. reinhardtii, such as psbS, the stress-related light harvesting complex, PSII protein phosphorylation and state-transitions are entirely absent or were barely detected in C. ohadii. Taken together, a unique photoinhibition protection mechanism evolved in C. ohadii, enabling the species to thrive under extreme-light intensities where other photo-synthetic organisms fail to survive.

plant biology↗

bioRxiv2018

Porcine Parvovirus VP1/VP2 on a Time Series Epitope Mapping: exploring the effects of high hydrostatic pressure on the immune recognition of antigens.

Porcine parvovirus (PPV) is a DNA virus that causes reproductive failure in gilts and sows, resulting in embryonic and fetal losses worldwide. Epitope mapping of PPV is important for developing new vaccines. In this study, we used spot synthesis analysis for epitope mapping of the capsid proteins of PPV (NADL-2 strain) and correlated the findings with predictive data from immunoinformatics. The virus was exposed to three conditions prior to inoculation in pigs: native (untreated), high hydrostatic pressure (350 MPa for 1 h) at room temperature and high hydrostatic pressure (350 MPa for 1h) at -18 {degrees}C, compared with a commercial vaccine produced using inactivated PPV. The screening of serum samples detected 44 positive spots corresponding to 20 antigenic sites. Each type of inoculated antigen elicited a distinct epitope set. In silico prediction located linear and discontinuous epitopes in B cells that coincided with several epitopes detected in spot synthesis of sera from pigs that received different preparations of inoculum. The approach used here provided important information on the antibody/antigen interactions required to improve B cell responses to PPV and may be useful in developing novel strategies for producing new vaccines.\n\nAbbreviations3D, three dimensional; HHP, high hydrostatic pressure; ID, identification; IEDB, Immune Epitope Database; ORFs, open reading frames; p.i., post-infection; PPV, porcine parvovirus; RMSD, root-mean-square deviation of atomic positions; R(g), radius of gyration. RMSF, root-mean-square fluctuation; SK6, Swine kidney cell; SPF, specific pathogen free; TCID50/mL, Median Tissue Culture Infectious Dose; HI, Hemagglutination Inhibition.

microbiology↗