Preliminary Studies on the Development of Monoclonal Antibodies Against Mycelia of Ganoderma boninense, the Causal Pathogen of Basal Stem Rot of Oil Palm

This study aimed to raise specific MAbs against G. boninense, the causal pathogen of basal stem rot (BSR) of oil palm. Crude mycelium extract of G. boninense was used as immunogen to generate MAbs. Mycelium was harvested from liquid culture and freeze-dried followed by re-suspension in phosphate buffer saline (PBS). Two 10-week old BALB-C mice were immunized with the mycelial extract. The mice were boosted once before harvesting their spleens for fusion. The MAbs were fused with myeloma cells from BALB-C mice. Initial screening was carried out using plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) with mycelial immunogen of G. boninense. The MAbs with positive signals were verified via secondary screening and cloned for cross-reactivity test. Cross-reactivity testing was carried out with 2 other fungi namely; Trichoderma and Botrytis along with 2 different species of Ganoderma commonly found in oil palm plantations namely; G. zonatum, and G. miniatocinctum. This study found that the MAbs raised against G. boninense were not specific as the MAbs gave positive signals through the cross-reactivity test with all fungi tested in the cross-reactivity. Future work would be using these MAbs in a co-immunization program whereby the generated Ganoderma sp generic monoclonal antibody will be pre-mixed with the G. boninense mycelium immunogen to allow reduction in the potential cross-reactivity of newly generated antibodies with Ganoderma sp. Our efforts are also currently directed at optimizing the immunogen preparation for the production of MAbs specific to G. boninense

Structural analysis of peptide helices containing centrally positioned lactic acid residues

The effect of insertion of lactic acid (Lac) residues into peptide helices has been probed using specifically designed sequences. The crystal structures of 11-residue and 14-residue depsipeptides Boc-Val-Val-Ala-Leu-Val-Lac-Leu-Aib-Val-Ala-Leu-OMe (1) and Boc-Val-Ala-Leu-Aib-Val-Ala-Leu-Val-Lac-Leu-Aib-Val-Ala-Leu-OMe (3), containing centrally positioned Lac residues, have been determined. The structure of an 11-residue peptide Boc-Val-Ala-Leu-Aib-Val-Ala-Leu-Aib-Val-Ala-Leu-OMe (2), analog of a which is an amide previously determined Lac-containing depsipeptide, Boc-Val-Ala-Leu-Aib-Val-Lac-Leu-Aib-Val-Ala-Leu-OMe I. L. Karle, C. Das, and P. Balaram, Biopolymers, Vol. 59, (2001) pp. 276-289], is also reported. Peptide 1 adopts a helical fold, which is stabilized by mixture of 4→1 and 5→1 hydrogen bonds. Peptide 2 adopts a completely α-helical conformation stabilized by eight successive 5→1 hydrogen bonds. Peptide 3 appears to be predominately α-helical, with seven 5→1 hydrogen bonds and three 4→1 interaction interspersed in the sequence. In the structure of peptide 3 in addition to water molecules in the head-to-tail region, hydration at an internal segment of the helix is also observed. A comparison of five related peptide helices, containing a single Lac residue, reveals that the hydroxy acid can be comfortably accommodated at interior positions in the helix, with the closest C=O...O distances lying between 2.8 and 3.3 Å

Tryptophan-containing peptide helices: Interactions involving the indole side chain

Two designed peptide sequences containing Trp residues at positions i and i + 5 (Boc-Leu-Trp-Val-Ala-Aib-Leu-Trp-Val-OMe, 1) as well as i and i + 6 (Boc-Leu-Trp-Val-Aib-Ala-Aib-Leu-Trp-Val-OMe, 2) containing one and two centrally positioned Aib residues, respectively, for helix nucleation, have been shown to form stable helices in chloroform solutions. Structures derived from nuclear magnetic resonance (NMR) data reveal six and seven intramolecularly hydrogen-bonded NH groups in peptides 1 and 2, respectively. The helical conformation of octapeptide 1 has also been established in the solid state by X-ray diffraction. The crystal structure reveals an interesting packing motif in which helical columns are stabilized by side chain-backbone hydrogen bonding involving the indole Nε1H of Trp(2) as donor, and an acceptor C=O group from Leu(6) of a neighboring molecule. Helical columns also associate laterally, and strong interactions are observed between the Trp(2) and Trp(7) residues on neighboring molecules. The edge-to-face aromatic interactions between the indoles suggest a potential C-H…π interaction involving the Cζ3H of Trp(2). Concentration dependence of NMR chemical shifts provides evidence for peptide association in solution involving the Trp(2) Nε1H protons, presumably in a manner similar to that observed in the crystal

Susceptible and Protective HLA Class 1 Alleles against Dengue Fever and Dengue Hemorrhagic Fever Patients in a Malaysian Population

BACKGROUND: The human leukocyte antigen alleles have been implicated as probable genetic markers in predicting the susceptibility and/or protection to severe manifestations of dengue virus (DENV) infection. In this present study, we aimed to investigate for the first time, the genotype variants of HLA Class 1(-A and -B) of DENV infected patients against healthy individuals in Malaysia. METHODOLOGY/PRINCIPAL FINDINGS: This study was carried out with 92 dengue disease patients and 95 healthy controls from three different ethnic groups (Malay, Chinese and Indian) in Malaysia. All patients with clinical and laboratory confirmation of DENV infection were typed for the HLA-A and B loci, using polymerase chain reaction-sequence specific primer techniques. In our total population, a significant increase for HLA-B*53 (P = 0.042, Pc = 1.008) allele and a significant decrease for A*03 (P = 0.015, Pc = 0.18, OR = 5.23, 95% CI = 1.19-23.02) and B*18 (P = 0.017, Pc = 0.408) alleles were noted in DHF patients as compared to healthy donors. We also observed that in the Malay DHF patients, allele B*13 (P = 0.049, Pc = 1.176, OR = 0.18, 95% CI = 0.03-0.90) was present at a significantly higher frequency in this population while allele HLA-B*18 (P = 0.024, Pc = 0.576) was seen to be negatively associated with DHF. CONCLUSIONS/SIGNIFICANCE: These are the first findings on genetic polymorphisms in our population and we conclude that: (1) In our total population, HLA-B*53 probably involve in disease susceptibility, while the HLA-A*03 and HLA-B*18 may confer protection from progression to severe disease; (2) In the Malay population, HLA-B*13 and B*18 are probably associated in disease susceptibility and protection, respectively. These results could furnish as a valuable predictive tool to identify ethnically different individuals at risk and/or protection from severe forms of DENV infection and would provide valuable informations for the design of future dengue vaccine

Stereochemistry of gabapentin and several derivatives: solid state conformations and solution equilibria

Gabapentin (1-(aminomethyl)cycloheaxaneacetic acid; Gpn) is a widely used anti-epileptic drug. The target site of action of Gpn remains controversial. Gpn can exist in two isomeric chair forms. The crystal structures of Gpn 1 and eight derivatives, Gpn hydrochloride 2, Gpn lactam 3, Boc-Gpn-OH 4, Ac-Gpn-OH 5, Piv- Gpn-OH 6, Tosyl-Gpn-OH 7, Boc-Gpn-OSu 8 and Boc-Gpn-NHMe 9, are described. The aminomethyl group occupies an axial position in 1, 3, 6 and 7, while it lies in an equatorial orientation in 2, 4, 5 and 8. The structure of Boc-Gpn-NHMe 9 reveals that the crystals contain both chair forms of the derivative in the ratio 0.7:0.3, favouring the aminomethyl group in an axial position. In all cases, the torsional angles about the Cα–Cβ (θ1) and Cβ–Cγ (θ2) bonds of the g-amino acid residue are characteristic of a gauche, gauche (g, g) conformation. In solution, NMR studies establish rapid conformational exchange, as anticipated, at room temperature. Low temperature NMR studies permit conformational freezing and determination of the freeenergy difference between the two 1,1-disubstituted cyclohexane conformers. The largest free-energy difference is observed in the free amino acid (0.38 kcal mol–1), with the most stable conformer having the aminomethyl group in the equatorial position. The free-energy difference between the two forms is significantly reduced in the protected derivatives, with almost equal populations observed in solution for the fully protected neutral derivatives, Boc-Gpn-NHMe and Gpn lactam

Studies on the Interaction of Schistosoma Mansoni and Leishmania Major in Experimentally Infected Balb/c Mice

Schistosoma mansoni and Leishmania major are important tropical human parasites. It is crucial to know the effect of the two infecting man concurrently. Two groups of BALB/c mice were infected with each of the parasites separately; another group was co-infected with both parasites and there was a na\uefve control. Draining lymph node and spleen cells from mice infected with either of the parasites showed high proliferative responses to their specific parasite antigen. However, crossreactivity occurred between S. mansoni and L. major. Spleen and Lymph node cells from co-infected group demonstrated high and sustained proliferative responses to schistosome soluble worm antigen preparation and killed Leishmania major antigen, respectively. There was high and sustained IgG levels for both the single and coinfected groups. At 10 weeks post-infection, co-infected mice had significantly larger nodules than mice with L. major infection alone. However, co-infected animals had less severe liver pathology and less enlarged mesenteric lymph nodes than those infected with S. mansoni only. This work shows that co-infection results in two different outcomes: protection against S. mansoni and exacerbated pathogy in L. major. We suggest that cellular responses possibly protect against S. mansoni, while high IgG levels lead to exacerbated L. major response

Production and Partial Characterization of Protease from Aspergillus Flavus using Rice Mill Waste as a Substrate and its Comparision with Aspergillus Niger Protease

Abstract Proteases are one of the most important groups of industrial enzymes and occur widely in plants an

Knowledge of dental academics about the COVID-19 pandemic: a multi-country online survey.

BACKGROUND: COVID-19 is a global pandemic affecting all aspects of life in all countries. We assessed COVID-19 knowledge and associated factors among dental academics in 26 countries. METHODS: We invited dental academics to participate in a cross-sectional, multi-country, online survey from March to April 2020. The survey collected data on knowledge of COVID-19 regarding the mode of transmission, symptoms, diagnosis, treatment, protection, and dental treatment precautions as well as participants' background variables. Multilevel linear models were used to assess the association between dental academics' knowledge of COVID-19 and individual level (personal and professional) and country-level (number of COVID-19 cases/ million population) factors accounting for random variation among countries. RESULTS: Two thousand forty-five academics participated in the survey (response rate 14.3%, with 54.7% female and 67% younger than 46 years of age). The mean (SD) knowledge percent score was 73.2 (11.2) %, and the score of knowledge of symptoms was significantly lower than the score of knowledge of diagnostic methods (53.1 and 85.4%, P <  0.0001). Knowledge score was significantly higher among those living with a partner/spouse than among those living alone (regression coefficient (B) = 0.48); higher among those with PhD degrees than among those with Bachelor of Dental Science degrees (B = 0.48); higher among those seeing 21 to 30 patients daily than among those seeing no patients (B = 0.65); and higher among those from countries with a higher number of COVID-19 cases/million population (B = 0.0007). CONCLUSIONS: Dental academics had poorer knowledge of COVID-19 symptoms than of COVID-19 diagnostic methods. Living arrangements, academic degrees, patient load, and magnitude of the epidemic in the country were associated with COVD-19 knowledge among dental academics. Training of dental academics on COVID-19 can be designed using these findings to recruit those with the greatest need

Knowledge of dental academics about the COVID-19 pandemic: a multi-country online survey

Background: COVID-19 is a global pandemic affecting all aspects of life in all countries. We assessed COVID-19 knowledge and associated factors among dental academics in 26 countries. Methods: We invited dental academics to participate in a cross-sectional, multi-country, online survey from March to April 2020. The survey collected data on knowledge of COVID-19 regarding the mode of transmission, symptoms, diagnosis, treatment, protection, and dental treatment precautions as well as participants’ background variables. Multilevel linear models were used to assess the association between dental academics’ knowledge of COVID-19 and individual level (personal and professional) and country-level (number of COVID-19 cases/ million population) factors accounting for random variation among countries. Results: Two thousand forty-five academics participated in the survey (response rate 14.3%, with 54.7% female and 67% younger than 46 years of age). The mean (SD) knowledge percent score was 73.2 (11.2) %, and the score of knowledge of symptoms was significantly lower than the score of knowledge of diagnostic methods (53.1 and 85.4%, P &lt; 0.0001). Knowledge score was significantly higher among those living with a partner/spouse than among those living alone (regression coefficient (B) = 0.48); higher among those with PhD degrees than among those with Bachelor of Dental Science degrees (B = 0.48); higher among those seeing 21 to 30 patients daily than among those seeing no patients (B = 0.65); and higher among those from countries with a higher number of COVID-19 cases/million population (B = 0.0007). Conclusions: Dental academics had poorer knowledge of COVID-19 symptoms than of COVID-19 diagnostic methods. Living arrangements, academic degrees, patient load, and magnitude of the epidemic in the country were associated with COVD-19 knowledge among dental academics. Training of dental academics on COVID-19 can be designed using these findings to recruit those with the greatest need