Biology subjects

Riad, M.

Publications and source records attributed to Riad, M..

4 recordsLinked to original sources

bioRxiv2026

Knowledge, Attitudes and Practices (KAP) of Cat Owners Towards Flea Infestation and Flea-Borne Diseases (FBDs) in Selected Regions of Bangladesh

Background: Flea infestation is an important companion-animal health problem and a prime source of zoonotic exposure. However, information on cat owners awareness and preventive behavior regarding fleas and flea-borne diseases (FBDs) in Bangladesh is limited. This study assessed the knowledge, attitudes and practices (KAP) of cat owners regarding flea infestation and flea-borne diseases in selected areas of central Bangladesh. Methods: A cross-sectional survey was conducted from November 2025 to July 2026 among 238 cat owners attending veterinary clinics in Savar, Dhamrai and Manikganj Upazila. Data were collected using a pretested structured questionnaire covering respondent characteristics, flea biology and transmission, perceived risks, and flea-prevention and control practices. Descriptive statistics were used to summarize the findings, and respondents were classified according to their overall KAP scores. Results: Of the respondents, 47.1% owned cats with outdoor access and 77.7% reported that their pets had previously experienced flea infestation. Although 65.5% used flea-control treatments, awareness of zoonotic and disease-transmission risks was limited. Only 14.7% recognized that fleas can parasitize humans, while 17.6% knew that fleas can transmit infectious agents. Overall, 83.2% of respondents had poor knowledge, whereas 69.7% demonstrated moderate attitudes and 63.9% showed moderate practices. Good knowledge and good practice were uncommon, accounting for only 3.8% and 4.6% of respondents, respectively. Veterinary recommendation was the most frequently reported motivation for using flea-control products. Conclusions: Cat owners attending in the surveyed areas frequently reported flea exposure and treatment use, but substantial gaps remained in their understanding of flea biology, zoonotic potential and comprehensive control. Targeted veterinary education emphasizing routine prevention, treatment of all susceptible household animals and environmental management is needed. These findings provide regional baseline evidence and should not be interpreted as nationally representative. Keywords: Bangladesh; cat owners; ectoparasites; flea-borne diseases; flea control; knowledge, attitudes and practices; One Health.

scientific communication and education↗

bioRxiv2026

Universal 3D Motif dynamics in RNA: The A-minor Switch

A-minor motifs consist of adenosines docking into adjacent RNA minor grooves, are the most prevalent 3D interaction stabilizing RNA structures, and widely considered as being static. NMR spectroscopy reveals a secondary structure equilibrium of these motifs between engaged and disengaged states, which we term the A-minor switch. A switch in E.coli ribosome helix 44 consists of a sparsely populated, transient single-nucleotide register shift that sequesters adenosines from their 3D structural A-minor contacts. Mutational trapping of the NMR-defined, A-minor-engaged ground and-disengaged excited state, combined with cryo-electron microscopy, visualizes this dynamic switch mechanism. Additionally, A-minor switches were identified using secondary structure ensemble analysis and mutational trapping was found to impair bacterial growth, directly linking RNA dynamics and function. Because A-minor motifs are widespread in structured RNAs, these findings establish A-minor switches as a general regulatory layer between secondary structure dynamics and tertiary contacts, exposing a new therapeutic target class.

biophysics↗

bioRxiv2021

5-hydroxymethylcytosine mediated active demethylation is required for neuronal differentiation and function

Although high levels of 5-hydroxymethylcytosine (5hmC) accumulate in neurons, it is not known whether 5hmC can serve as an intermediate in DNA demethylation in postmitotic neurons. We report high resolution mapping of DNA methylation and hydroxymethylation, chromatin accessibility, and histone marks in developing postmitotic Purkinje cells (PCs). Our data reveal new relationships between PC transcriptional and epigenetic programs, and identify a class of genes that lose both 5mC and 5hmC during terminal differentiation. Deletion of the 5hmC writers Tet1, Tet2, and Tet3 from postmitotic PCs prevents loss of 5mC and 5hmC in regulatory domains and gene bodies and hinders transcriptional and epigenetic developmental transitions, resulting in hyper-excitability and increased susceptibility to excitotoxic drugs. Our data demonstrate that Tet-mediated active DNA demethylation occurs in vivo, and that acquisition of the precise molecular and electrophysiological properties of adult PCs requires continued oxidation of 5mC to 5hmC during the final phases of differentiation.

neuroscience↗

bioRxiv2018

Behavioral phenotyping of an improved mouse model of Phelan-McDermid Syndrome with a complete deletion of the Shank3 gene

AbstractPhelan-McDermid Syndrome (PMS) is a rare genetic disorder in which one copy of the SHANK3 gene is missing or mutated, leading to a global developmental delay, intellectual disability, and autism. Multiple intragenic promoters and alternatively spliced exons are responsible for the formation of numerous isoforms. Many genetically-modified mouse models of PMS have been generated but most disrupt only some of the isoforms. In contrast, the vast majority of known SHANK3 mutations found in patients involve deletions that disrupt all isoforms. Here, we report the production and thorough behavioral characterization of a new mouse model in which all Shank3 isoforms are disrupted. Our mice are more severely affected than previously published models. While the deficits were typically more pronounced in homozygotes, an intermediate phenotype was observed for heterozygotes in many paradigms. As in other Shank3 mouse models, stereotypies, including increased grooming, were observed. Additionally, both sensory and motor deficits were detected in neonatal and adult mice. While social behaviors were not strongly impacted, Shank3-deficient mice displayed a strong escape behavior and avoidance of inanimate objects indicating increased novelty-induced anxiety. Similarly, increased freezing was observed during fear conditioning training and amygdala-dependent cued retrieval. Finally, deficits were observed in both initial training and reversal in the Barnes maze and in contextual fear memory that are memory tasks involving hippocampal-prefrontal circuits. This new mouse model of PMS, engineered to most closely represent human mutations, recapitulates core symptoms of PMS providing improvements for both construct and face validity, compared to previous models.\n\nSignificant statementPhelan-McDermid syndrome, caused by happloinsufficiency of Shank3, is a severe and complex neurodevelopmental disorder. This study investigates the behavioral consequences of a disruption of all Shank3 isoforms in neonatal and adult mice using a detailed battery of tests tailored to investigate core symptoms and usual comorbidities of PMS. We found that our new model is more severely affected than previously published mouse models with only partial deletions of Shank3 and more closely recapitulates symptoms of PMS thus providing improvements for both construct and face validity. Our results highlight the significance of using a mouse model with a complete deletion of Shank3 for studying mechanisms underlying autism spectrum disorder and PMS, carrying preclinical studies and testing test novel therapeutic approaches.

animal behavior and cognition↗