Yeast Cdc48 is a well-conserved, essential chaperone of ATPases associated with diverse cellular activity (AAA) proteins, which recognizes substrate proteins and modulates their conformations to carry out many cellular processes. However, the fundamental mechanisms underlying the diverse pivotal roles of Cdc48 remain unknown. Almost all AAA proteins form a ring-shaped structure with a conserved aromatic amino acid residue that is essential for proper function. The threading mechanism hypothesis suggests that this residue guides the intrusion of substrate proteins into a narrow pore of the AAA ring, thereby becoming unfolded. By contrast, the aromatic residue in one of the two AAA rings of Cdc48 has been eliminated through evolution. Here, we show that artificial retrieval of this aromatic residue in Cdc48 is lethal, and essential features to support the threading mechanism are required to exhibit the lethal phenotype. In particular, genetic and biochemical analyses of the Cdc48 lethal mutant strongly suggested that when in complex with the 20S proteasome, essential proteins are abnormally forced to thread through the Cdc48 pore to become degraded, which was not detected in wild-type Cdc48. Thus, the widely applicable threading model is less effective for wild-type Cdc48; rather, Cdc48 might function predominantly through an as-yet-undetermined mechanism.

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Milk is such a food which can meet almost all nutritional needs of human lives. Raw or unprocessed milk supports the growth of wide variety of microorganisms. The major interests of this study were examining the microbial quality of raw milk collected from different locations of Jessore city in Bangladesh and determining antibiotic susceptibility pattern of some isolated bacteria. To do so, 12 raw milk samples were collected from different areas of Jessore city. Microbial analysis comprised of enumeration of TVC (total viable count), TCC (total coliform count) and TSC (total staphylococcal count). The highest TVC, TCC and TSC were 1.95x10 9 CFU/ml, 2.5x10 7 CFU/ml and 1.02x10 7 CFU/ml respectively. Prevalent bacterial populations were Klebsiella spp., Enterobacter spp., Shigella spp. Staphylococcus spp., Escherichia coli and Citrobacter spp. In order to observe the antibiotic susceptibility pattern, the antibiotic sensitivity test was performed for some randomly selected isolates of E. coli and Klebsiella spp. More than 90% isolates of Klebsiella spp. were found to be resistant against Erythromycin whereas more than 90% isolates were sensitive against Imipenem. On the other hand, 100% E. coli isolates were observed as resistant against Erythromycin and in case of Trimethopreme 100% isolates were sensitive. Multidrug resistance pattern was also found. These results suggest the necessity of hygienic practices during handling, processing and post-processing of raw milk to improve the microbiological quality and safety of raw milk.

Background and Aim: The use of antibiotic growth promoters (AGPs) in the poultry industry has raised concern because of their potential harm to human health. Emerging evidence suggests that probiotics are a safer substitute, although little research has explored this in Bangladesh. We recently isolated local bacterial strains with probiotic properties. We aimed to determine their impact on the growth, hematobiochemical parameters, and production costs of broiler chicks relative to that of a commercial probiotic (CP) and AGP. Materials and Methods: Day-old male broiler chicks (Cobb 500, n=63) were divided equally into three experimental groups (three replicates per group and seven chicks per replicate). First group was fed a basal diet supplemented with the AGP, ciprofloxacin (CTL group), second group was fed a basal diet supplemented with the CP, Protexin® (CP group), and the third group was fed a basal diet supplemented with our isolated bacterial strains (study probiotic [SP] group) for 36 days. Body weight was recorded daily, and relative growth rate (RGR), feed conversion ratio (FCR), and organ weights and carcass yields were calculated at the study's end. Blood obtained on day 36 was used to determine the number of red blood cell (RBC) and white blood cells (WBCs), hemoglobin (Hb) concentration, packed cell volume, erythrocyte sedimentation rate, as well as levels of serum glucose, total and high-density lipoprotein (HDL) cholesterol, and triglycerides (TGs). Total production costs were estimated by summing the variable and fixed costs. Results: Chicks in both the CP and SP groups experienced significant decreases in blood glucose levels and significant increases in BW, RGR, FCR, levels of RBC and WBC, Hb concentration, and packed cell volume compared with those in the CTL group (p<0.05 for all). Our data suggested a numerical reduction (p>0.05) in levels of total cholesterol, TGs, and HDL in the SP and CP groups when compared to the CTL group. In addition, both CP and SP treatments resulted in significant (p<0.05) gains in net profit compared with the treatment given to the CTL group. Conclusion: Administration of probiotics, either from a commercialized or local source, led to greater improvements in growth, hematological parameters, and net profits of broiler chicks when compared with that of an AGP. This suggests that they are suitable alternatives to the AGPs used in poultry feed and that our isolated strains, in particular, are an ideal option for farmers in Bangladesh.