Psychological impact and stress factors among Ha'il medical students post COVID19 pandemic

The current COVID-19 pandemic frightfully threatened the whole world, and people in different countries were demanded to be quarantined due to possible contact with the infection. High mortality rate, the spread of COVID19 and the propagation of fake news in social media programs created fear and anxiety among majority of society especially, medical students. One of the most essential changes during the covid-19 was the termination of teaching lectures in physical presence and its replacement by virtual online lectures. Circumstances like these have negative impact on the mental health of medical students. Therefore, it is of interest to investigate the impact of the COVID19 pandemic on medical students’ learning and the effect of distressing situation they experienced, psychological and educational variables specifically during return to physical attendance in college and the impact of these variables of probably affecting factors like age, gender, marital status, transition of preclinical years to clinical years. A Cross-sectional study was completed among medical students at UOH, KSA. The data are collected by distributing an online questionnaire. Statistical analysis has been done with Microsoft Power BI. 14.82% of 5th year female participants were unable to stop worrying for different things while 10.54% of male participant were in the 1st year. Large numbers of students who have increased the number of times they wash their hands are found in med3 and med4 while 27.92% agree and 29.05% strongly agree of whole years of study. 45.29% of students were having mental pressure before online session due to internet connection while 51.55% had decreased motivation since the shift to online learning. Data shows that highest numbers of participants who were having past illness and anxious were in age group 21-23 in both male and female. The majority of students was having fear toward returning in physical presence and preferred not to have on- college education. Hence, it is recommended to encourage students and reduce stress by providing with Personal Protective Equipment (PPE) course.     

Autophagy gets a brake: DAP1, a novel mTOR substrate,is activated to suppress the autophagic process

Autophagy, a highly regulated catabolic process, is controlled by the action of positive and negative regulators. While many of the positive mediators of autophagy have been identified, very little is known about negative regulators that might counterbalance the process. We recently identified death-associated protein 1 (DAP1) as a suppressor of autophagy and as a novel direct substrate of mammalian target of rapamycin (mTOR). We found that DAP1 is functionally silent in cells growing under rich nutrient supplies through mTOR-dependent inhibitory phosphorylation on two sites, which were mapped to Ser3 and Ser51. During amino acid starvation, mTOR activity is turned off resulting in a rapid reduction in the phosphorylation of DAP1. This caused the conversion of the protein into a suppressor of autophagy, thus providing a buffering mechanism that counterbalances the autophagic flux and prevents its overactivation under conditions of nutrient deprivation. Based on these studies we propose the “gas and brake” concept in which mTOR, the main sensor that regulates autophagy in response to amino acid deprivation, also controls the activity of a specific balancing brake to prevent the overactivation of autophagy.Key words: DAP1, mTOR, autophagy, amino acid starvation, phosphorylationIn recent years, many of the genes controlling and executing the autophagic process have been identified. Most of these genes act as positive mediators of the various steps of the process, including the ULK1 complex, which regulates the induction step, the Vps34-Beclin 1 complex that participates in the vesicle nucleation step and two ubiquitin-like pathways, the Atg12-Atg5 and the LC3-phosphatidylethanolamine (PE) conjugation steps, which play a central role in the vesicle elongation process. To date, only a few negative regulators of autophagy have been identified, including mTOR and the anti-apoptotic Bcl-2 family members. mTOR Ser/Thr kinase is a central suppressor of autophagy acting at the initiating regulatory steps of the process. Many signaling pathways act to inhibit mTOR activity, thus relieving its inhibitory effects on autophagy. The anti-apoptotic Bcl-2 and Bcl-X_L proteins, on the other hand, act at the nucleation step, by directly binding to Beclin 1''s BH3 domain, thus reducing the activation of Vps34 and subsequent autophagy. This inhibition can be relieved through dissociation of the complex, following either JNK-1 mediated phosphorylation of Bcl-2 or DAP kinase-mediated phosphorylation of the BH3 domain of Beclin 1.DAP1 is a small (∼15 kDa), ubiquitously expressed protein, rich in prolines and lacking known functional motifs. DAP1 was isolated more than a decade ago in our laboratory using a functional approach to gene cloning aimed at identifying novel mediators of IFNγ-induced cell death in mammalian cell cultures. Until recently, very little was known about the cellular and molecular functions of DAP1, mainly due to the lack of homology to other known proteins and the lack of functional motifs that could indicate a possible cellular function and studies in mammalian systems were missing.Recently, we discovered that DAP1 is another negative regulator of autophagy; yet, interestingly, its suppressive activity is selectively turned on during the autophagic process. Moreover, we found that DAP1 suppressive activity is tightly linked to the status of mTOR kinase activity. Under nutrient-rich culture conditions, DAP1 is phosphorylated by mTOR on two sites, Ser3 and Ser51, resulting in its inactivation. In response to nutrient deprivation, mTOR is inhibited and DAP1 undergoes rapid dephosphorylation. By knocking down the endogenous DAP1 and introducing either the phosphomimetic or the nonphosphorylatible DAP1 mutants, we found that the dephosphorylation leads to activation of the autophagic suppressive function of DAP1, whereas the phophorylated form is inactive. These results led to a “gas and brake” model, in which at the same time that autophagy is induced, some brakes such as DAP1 are also activated to provide a buffering mechanism that counterbalances the autophagic flux and prevents its overactivation under nutrient-deprivation conditions (Fig. 1). Notably, balancing autophagy is extremely important, since deregulated or excessive autophagy has been implicated in the pathogenesis of diverse diseases, such as certain types of neuronal degeneration and cancer and also in cellular aging.Open in a separate windowFigure 1“Gas and brake” model. During nutrient-rich conditions, active mTORC1 phosphorylates and inactivates the components of the ULK1 complex, ULK1 and Atg13, thus preventing the induction of autophagy. DAP1 is also inactivated simultaneously by mTORC1-mediated phosphorylation on Ser3 and Ser51. In addition, mTORC1 phosphorylates and activates p70S6K and 4E-BP1, which mediate the protein translation and cell growth activities of mTOR. Upon nutrient starvation, mTORC1 activity is attenuated, leading to dephosphorylation and activation of ULK1. ULK1, in turn, undergoes autophosphorylation and phosphorylates Atg13 and FIP200 resulting in ULK1 complex activation and induction of autophagy. On the other hand, activation of DAP1 by dephosphorylation, results in suppression of autophagy, thus inserting a brake into the process of autophagy. Note that the inactive proteins/complexes are faded out.The current challenge is to identify the molecular basis of the suppressive functions of DAP1 on autophagy. We have recently shown that DAP1 knockdown enhances LC3 lipidation and autophagosome accumulation both during amino acid starvation and rapamycin treatment. In addition, preliminary data indicate that the knockdown of DAP1 has no effect on mTOR complex 1 (mTORC1) activity in cells, at least during the first hours of starvation. Accordingly, DAP1 may function between the mTORC1 and the LC3 conjugation systems. The potential targets may fall into one of the multiprotein complexes functioning downstream of mTOR such as the ULK1 complex, the Vps34-Beclin 1 complex and more. Future studies will be performed to identify the molecular mechanism by which DAP1 suppresses autophagy. The lack of known functional motifs in the DAP1 protein sequence suggests that this small proline-rich protein may function as an adaptor blocking autophagy by binding to critical protein partners that still await identification.Although autophagy is primarily a protective process for the cell, it can also play a role in cell death. In response to prolonged starvation, autophagy can act either as a cell survival mechanism or be recruited as a cell death executer. In the future it would be interesting to examine whether the autophagy enhancement resulting from DAP1 knockdown contributes to increased cell death in our system or even may convert the survival properties of autophagy into death induction. This will fit the “gas and brake” model, in which autophagy, which is initially recruited as a cell survival mechanism, is converted into cell death machinery when a certain threshold is crossed due to the loss of the “brake” by the knockdown of DAP1.To date, very little is known about the putative mechanisms that restrict the intensity of the autophagic flux to maintain the continuous benefits of this process under stress. Therefore, the ability of DAP1 to counterbalance and buffer the process in a manner that is tightly linked to the status of a central player in autophagy (i.e., mTOR) is an important discovery in this field and provides a target for future drug design.     

Deconstructing the mouse olfactory percept through an ethological atlas

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Molecular characterization of Borrelia persica, the agent of tick borne relapsing fever in Israel and the Palestinian Authority

The identification of the Tick Borne Relapsing Fever (TBRF) agent in Israel and the Palestinian Authority relies on the morphology and the association of Borrelia persica with its vector Ornithodoros tholozani. Molecular based data on B. persica are very scarce as the organism is still non-cultivable. In this study, we were able to sequence three complete 16S rRNA genes, 12 partial flaB genes, 18 partial glpQ genes, 16 rrs-ileT intergenic spacers (IGS) from nine ticks and ten human blood samples originating from the West Bank and Israel. In one sample we sequenced 7231 contiguous base pairs that covered completely the region from the 5'end of the 16S rRNA gene to the 5'end of the 23S rRNA gene comprising the whole 16S rRNA (rrs), and the following genes: Ala tRNA (alaT), Ile tRNA (ileT), adenylosuccinate lyase (purB), adenylosuccinate synthetase (purA), methylpurine-DNA glycosylase (mag), hypoxanthine-guanine phosphoribosyltransferase (hpt), an hydrolase (HAD superfamily) and a 135 bp 5' fragment of the 23S rRNA (rrlA) genes. Phylogenic sequence analysis defined all the Borrelia isolates from O. tholozani and from human TBRF cases in Israel and the West Bank as B. persica that clustered between the African and the New World TBRF species. Gene organization of the intergenic spacer between the 16S rRNA and the 23S rRNA was similar to that of other TBRF Borrelia species and different from the Lyme disease Borrelia species. Variants of B. persica were found among the different genes of the different isolates even in the same sampling area.     

Synthesis and antiprotozoal activity of novel bis-benzamidino imidazo[1,2-a]pyridines and 5,6,7,8-tetrahydro-imidazo[1,2-a]pyridines

The key dinitrile intermediates 4a-d were synthesized by reaction of phenacyl bromide 1 and the appropriate 2-amino-5-bromopyridines to yield 3a-d. Suzuki coupling of 3a-d with 4-cyanophenylboronic acid yielded the 2,6-bis(4-cyanophenyl)-imidazo[1,2-a]pyridine derivatives 4a-d. The bis-amidoximes 5a-d, obtained from 4a-d by the action of hydroxylamine, were converted to the bis-O-acetoxyamidoximes which on catalytic hydrogenation in a mixture of ethanol/ethyl acetate gave the acetate salts of 2,6-bis[4-(amidinophenyl)]-imidazo[1,2-a]pyridines 7a-d. In contrast, catalytic hydrogenation of the bis-O-acetoxyamidoxime of 5a in glacial acetic acid gave the saturated analogue 2,6-bis[4-(amidinophenyl)]-5,6,7,8-tetrahydro-imidazo[1,2-a]pyridine 8. O-Methylation of the amidoximes 5a-d gave the N-methoxyamidines 6a-d. The diamidines showed strong DNA binding affinity, were very active in vitro against T. b. r. exhibiting IC(50) values between 7 and 38nM, but were less effective against P. f. with IC(50) values between 23 and 92nM. Two of the diamidines 7c and 7d were slightly more active than furamidine but less active than azafuramidine in the T. b. r. STIB900 mouse model. Only one prodrug 6b showed moderate activity in the same mouse model.     

Diagnostic deficiencies of C. difficile infection among patients in a tertiary hospital in Saudi Arabia: A laboratory-based case series

Clostridioides difficile infection (CDI) has become a threatening public health problem in the developed world. In the kingdom of Saudi Arabia, prevalence of CDI is still unknown due to limited surveillance protocols and diagnostic resources. We used a two-step procedure to study and confirm C. difficile cases. We also studied toxin profiles of these isolates.Stool samples were collected from symptomatic patients and clinically suspected of CDI for almost 12 months. Isolates were confirmed by culture method followed by 16S rRNA sequencing. Multiplex PCR was performed for the identification of toxin A, toxin B and binary toxin genes and compared to Gene Expert results.Out of the 47 collected samples, 27 were successfully grown on culture media. 18 samples were confirmed as C. difficile by both culture and 16S rRNA sequencing. Interestingly, the rest of the isolates (9 species) belonged to different genera. Our results showed 95% of samples were positive for both toxin A and B (tcdA, tcdB) and all samples exhibited the toxin gene regulator tcdC. All samples were confirmed negative for the binary toxin gene ctdB and 11% of the isolates were positive for ctdA gene. Interestingly, one isolate harbored the binary toxin gene (cdtA⁺) and tested negative for both toxins A and B.We believe that combining the standard culture method with molecular techniques can make the detection of C. difficile more accurate.