Non-invasive prediction of maca powder adulteration using a pocket-sized spectrophotometer and machine learning techniques.

Discriminating different cultivars of maca powder (MP) and detecting their authenticity after adulteration with potent adulterants such as maize and soy flour is a challenge that has not been studied with non-invasive techniques such as near infrared spectroscopy (NIRS). This study developed models to rapidly classify and predict 0, 10, 20, 30, 40, and 50% w/w of soybean and maize flour in red, black and yellow maca cultivars using a handheld spectrophotometer and chemometrics. Soy and maize adulteration of yellow MP was classified with better accuracy than in red MP, suggesting that red MP may be a more susceptible target for adulteration. Soy flour was discovered to be a more potent adulterant compared to maize flour. Using 18 different pretreatments, MP could be authenticated with R2CV in the range 0.91-0.95, RMSECV 6.81-9.16 g/,100 g and RPD 3.45-4.60. The results show the potential of NIRS for monitoring Maca quality.

Effects of vasoactive substances on biomechanics of small resistance arteries of male and female Dahl salt-sensitive rats.

Changes in vascular biomechanics leading to increase in arterial stiffness play a pivotal role in circulatory dysfunction. Our objectives were to examine sex-specific pharmacological changes related to the biomechanics and any structural modifications in small resistance arteries of Dahl salt-sensitive male and female rats. The composite Young modulus (CYM) was determined using pressure myograph recordings, and immunohistochemistry was used for the evaluation of any structural changes in the third-order mesenteric arteries (n = 6). Animals on high-salt diet developed hypertension with significant elevation in central and peripheral blood pressures and pulse wave velocity compared to those on regular diet. There were no significant differences observed in the CYM between any of the groups (i.e., males and females) in vehicle-treated time-control studies. The presence of verapamil (0.3 µM) significantly reduced CYM in hypertensive males without changes within females compared to vehicle. This effect was abolished by phenylephrine (0.3 µM). BaCl2 (100 µM), ouabain (100 µM), and L-NAME (0.3 µM) combined significantly increased CYM in vessels from in normotensive males and females but not in hypertensive males compared to vehicle. The increase in CYM was abolished in the presence of phenylephrine. Sodium nitroprusside (0.3 µM), in the presence of phenylephrine, significantly reduced CYM in male normotensive versus hypertensive, with no differences within females. Significant differences were observed in immunohistochemical assessment of biomechanical markers of arterial stiffness between males and females. Our findings suggest sex possibly due to pressure differences to be responsible for adaptive changes in biomechanics, and varied pharmacological responses in hypertensive state.

Antimicrobial effects of Medicines for Malaria Venture Pathogen Box compounds on strains of Neisseria gonorrhoeae.

Therapeutic options for Neisseria gonorrhoeae are limited due to emerging global resistance. New agents and treatment options to treat patients with susceptible and multi-extensively drug-resistant N. gonorrhoeae is a high priority. This study used an in vitro approach to explore the antimicrobial potential, as well as synergistic effects of Medicine for Malaria Venture (MMV) Pathogen Box compounds against ATCC and clinical N. gonorrhoeae strains. Microbroth dilution assay was used to determine pathogen-specific minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the Pathogen Box compounds against susceptible and resistant N. gonorrhoeae strains, with modification, by adding PrestoBlue HS Cell Viability Reagent. A checkerboard assay was used to determine synergy between the active compounds and in conjunction with ceftriaxone. Time-kill kinetics was performed to determine if the compounds were either bactericidal or bacteriostatic. The Pathogen Box compounds: MMV676501, MMV002817, MMV688327, MMV688508, MMV024937, MMV687798 (levofloxacin), MMV021013, and MMV688978 (auranofin) showed potent activity against resistant strains of N. gonorrhoeae at an MIC and MBC of ≤10 µM. Besides the eight compounds, MMV676388 and MMV272144 were active against susceptible N. gonorrhoeae strains, also at MIC and MBC of ≤10 µM. All the compounds were bactericidal and were either synergistic or additive with fractional inhibitory concentration index ranging between 0.40 and 1.8. The study identified novel Pathogen Box compounds with potent activity against N. gonorrhoeae strains and has the potential to be further investigated as primary or adjunctive therapy to treat gonococcal infections.

Combined effects of shade and drought on physiology, growth, and yield of mature cocoa trees.

Climate models predict decreasing precipitation and increasing air temperature, causing concern for the future of cocoa in the major producing regions worldwide. It has been suggested that shade could alleviate stress by reducing radiation intensity and conserving soil moisture, but few on-farm cocoa studies are testing this hypothesis. Here, for 33 months, we subjected twelve-year cocoa plants in Ghana to three levels of rainwater suppression (full rainwater, 1/3 rainwater suppression and 2/3 rainwater suppression) under full sun or 40 % uniform shade in a split plot design, monitoring soil moisture, physiological parameters, growth, and yield. Volumetric soil moisture (Ï´w) contents in the treatments ranged between 0.20 and 0.45 m3m-3 and increased under shade. Rainwater suppression decreased leaf water potentials (ѱw), reaching -1.5 MPa in full sun conditions indicating severe drought. Stomatal conductance (gs) was decreased under the full sun but was not affected by rainwater suppression, illustrating the limited control of water loss in cocoa plants. Although pre-dawn chlorophyll fluorescence (Fv/Fm) indicated photoinhibition, rates of photosynthesis (Pn) were highest in full sun. On the other hand, litter fall was highest in the full sun and under water stress, while diameter growth and carbon accumulation increased in the shade but was negatively affected by rainwater suppression. Abortion of fruits and damage to pods were high under shade, but dry bean yield was higher compared to under the full sun. The absence of interactions between shade treatments and rainwater suppression suggests that shade may improve the performance of cocoa, but not sufficiently to counteract the negative effects of water stress under field conditions.

Examining the level of public awareness on the Sustainable Development Goals in Africa: An empirical evidence from Ghana.

Nations which are part of the United Nations are required to institute appropriate measures to fulfil the vision of the Sustainable Development Goals (SDGs). However, for this to be possible, all stakeholders including the general public need to be fully aware of the SDGs. This research examined the level of public awareness about the SDGs among Ghanaians based on the views of 431 respondents. Means, standard deviation, Mann-Whitney U test, Kruskal Wallis and Pearson Product-Moment Correlations were used for data analysis. The study found that awareness level on SDG 1 (ending poverty), SDG 2 (zero hunger, food security, nutrition and sustainable agriculture), SDG 3 (health and well-being), SDG 5 (gender equality), and SDG 6 (clean water and sanitation) was high among Ghanaians. However, awareness level on SDG 9 (industry, innovation and infrastructure), SDG 14 (conservation of life below water), and SDG 16 (peace, justice and strong institutions) was very low among Ghanaians. No significant difference manifested in the level of awareness among male and female Ghanaians. There were statistically significant differences in educational levels of respondents and their overall level of awareness of the SDGs. Also, there was a low, negative correlation between overall level of awareness and the effectiveness of the communication strategies used in creating awareness about the SDGs. Government should re-examine its communication strategies on the SDGs and put in place a more effective communication policy framework which involves grassroots populations and local communities.

Pharmacognosy and Effects of Cannabinoids in the Vascular System.

Understanding the pharmacodynamics of cannabinoids is an essential subject due to the recent increasing global acceptance of cannabis and its derivation for recreational and therapeutic purposes. Elucidating the interaction between cannabinoids and the vascular system is critical to exploring cannabinoids as a prospective therapeutic agent for treating vascular-associated clinical conditions. This review aims to examine the effect of cannabinoids on the vascular system and further discuss the fundamental pharmacological properties and mechanisms of action of cannabinoids in the vascular system. Data from literature revealed a substantial interaction between endocannabinoids, phytocannabinoids, and synthetic cannabinoids within the vasculature of both humans and animal models. However, the mechanisms and the ensuing functional response is blood vessels and species-dependent. The current understanding of classical cannabinoid receptor subtypes and the recently discovered atypical cannabinoid receptors and the development of new synthetic analogs have further enhanced the pharmacological characterization of the vascular cannabinoid receptors. Compelling evidence also suggest that cannabinoids represent a formidable therapeutic candidate for vascular-associated conditions. Nonetheless, explanations of the mechanisms underlining these processes are complex and paradoxical based on the heterogeneity of receptors and signaling pathways. Further insight from studies that uncover the mechanisms underlining the therapeutic effect of cannabinoids in the treatment of vascular-associated conditions is required to determine whether the known benefits of cannabinoids thus currently outweigh the known/unknown risks.

Mycobacterium tuberculosis Drug Resistance in Ethiopia: An Updated Systematic Review and Meta-Analysis.

Background: Tuberculosis (TB) remains a significant global public health issue, despite advances in diagnostic technologies, substantial global efforts, and the availability of effective chemotherapies. Mycobacterium tuberculosis, a species of pathogenic bacteria resistant to currently available anti-TB drugs, is on the rise, threatening national and international TB-control efforts. This systematic review and meta-analysis aims to estimate the pooled prevalence of drug-resistant TB (DR-TB) in Ethiopia. Materialsand Methods: A systematic literature search was undertaken using PubMed/MEDLINE, HINARI, the Web of Science, ScienceDirect electronic databases, and Google Scholar (1 January 2011 to 30 November 2020). After cleaning and sorting the records, the data were analyzed using STATA 11. The study outcomes revealed the weighted pooled prevalence of any anti-tuberculosis drug resistance, any isoniazid (INH) and rifampicin (RIF) resistance, monoresistance to INH and RIF, and multidrug-resistant TB (MDR-TB) in newly diagnosed and previously treated patients with TB. Results: A total of 24 studies with 18,908 patients with TB were included in the final analysis. The weighted pooled prevalence of any anti-TB drug resistance was 14.25% (95% confidence interval (CI): 7.05-21.44%)), whereas the pooled prevalence of any INH and RIF resistance was found in 15.62% (95%CI: 6.77-24.47%) and 9.75% (95%CI: 4.69-14.82%) of patients with TB, respectively. The pooled prevalence for INH and RIF-monoresistance was 6.23% (95%CI: 4.44-8.02%) and 2.33% (95%CI: 1.00-3.66%), respectively. MDR-TB was detected in 2.64% (95%CI: 1.46-3.82%) of newly diagnosed cases and 11.54% (95%CI: 2.12-20.96%) of retreated patients with TB, while the overall pooled prevalence of MDR-TB was 10.78% (95%CI: 4.74-16.83%). Conclusions: In Ethiopia, anti-tuberculosis drug resistance is widespread. The estimated pooled prevalence of INH and RIF-monoresistance rates were significantly higher in this review than in previous reports. Moreover, MDR-TB in newly diagnosed cases remained strong. Thus, early detection of TB cases, drug-resistance testing, proper and timely treatment, and diligent follow-up of TB patients all contribute to the improvement of DR-TB management and prevention. Besides this, we urge that a robust, routine laboratory-based drug-resistance surveillance system be implemented in the country.

Knowledge and awareness of mitochondrial diseases among physicians in the tertiary hospitals in Ghana.

BACKGROUND: Mitochondrial diseases/disorders (MDs), for decades, have been identified as a key underlying condition for many chronic diseases globally. However, data on the knowledge and prevalence of MDs in many countries in sub-Saharan Africa are lacking. This study assessed the knowledge, and awareness, of MDs among senior medical doctors in the five tertiary hospitals in Ghana. METHOD: Data were collected from one hundred and twenty-eight (128) medical doctors in the five Tertiary Hospitals in Ghana using both closed and open-ended questionnaires and analysed using descriptive statistics. RESULTS: Of the 128 respondents, 70.32% were senior medical officers and above, 87% of them indicated that they were aware of MDs and over 90% said physicians do not often diagnose MDs in Ghana. About 81% indicated that MDs are associated with chronic illnesses whilst 72% said the disease is diagnosed in both males and females. About 45% of the respondents alluded to the fact that MDs are difficult to diagnose, are associated with mutations in both the mitochondrial and the nuclear DNA, and are non-infectious diseases. Approximately 85% said nervous system dysfunction and muscle weakness are some of the symptoms associated with MDs whilst 77% said fatigue is also one of the symptoms. About 38% of the respondents specified that they encounter myopathies. A majority (70%) did not know about the availability of any consensus or standard diagnostic procedure and/or drugs for MDs. CONCLUSION: There is a high level of knowledge and awareness of MDs among the respondents. However, there is a low disease encounter, which could be due to a lack of diagnostic protocols or a low disease prevalence. It is, therefore recommend that a patient perspective study, which looks at clinical records and laboratory data be conducted to fully ascertain the prevalence of MDs in Ghana and that appropriate educational strategies and interventions aimed at improving the diagnosis of mitochondrial diseases in Ghana be put in place.

Differential biomechanics in resistance arteries of male compared with female Dahl hypertensive rats.

BACKGROUND: Increase in vascular stiffness is associated with a higher risk of cardiovascular morbidity and mortality and is likely sex-specific. METHOD: Our objectives were to compare structural and functional alterations in small resistance arteries as related to vascular stiffness from Dahl salt-sensitive male and female rats (n = 8, mean ±â€Šs.e.m.). RESULTS: Arterial blood pressure and pulse wave velocity were significantly (P < 0.05) elevated in males (161 ±â€Š3 mmHg; 6.4 ±â€Š0.2 m/s) and females (147 ±â€Š2 mmHg; 5.5 ±â€Š0.1 m/s) on a high (H) salt compared with regular (R) diets but were significantly higher in males (H) than in all others. Significant increases in collagen and smooth muscle cell areas were evident in ultrastructure of mesenteric arteries of hypertensive males compared to normotensive or corresponding females. There were no significant differences in composite Young's modulus (CYM) between groups. Vasoconstriction resulted in significantly higher CYM in male (H: 8.6 ±â€Š1 KPa) than R (4.5 ±â€Š0.8 KPa), and the corresponding females (H: 5.6 ±â€Š0.6 KPa and R: 5 ±â€Š0.9 KPa). In contrast, vasodilation significantly reduced CYM in the male groups (H: 2.5 ±â€Š0.4 KPa and R: 2.7 ±â€Š0.5 KPa) compared with the corresponding values in females (H: 4.2 ±â€Š0.6 KPa and R: 5 ±â€Š0.5 KPa). Moreover, the slope of pressure-volume curves revealed significantly greater distended vascular compliance in male H than R, and the corresponding females. CONCLUSION: Our findings are supportive of a link between high salt intake and elevated blood pressure as being sex specific, likely involving sex-dependent changes in ultrastructure of the vessels, which ultimately may alter the biomechanics, and thus, the haemodynamic functions of both macro-circulation and micro-circulations.

Association between Antiretroviral Treatment and Markers of Systemic Inflammation among HIV Patients in Ghana.

BACKGROUND: Studies from high-income countries have reported that even after receiving antiretroviral treatment (ART), HIV-infected adults may not achieve normal levels of certain inflammatory markers that are known to be associated with the onset and development of non-communicable diseases. OBJECTIVE: The aim of this study is to examine the relationship between ART and markers of systemic inflammation in HIV/AIDS patients at an urban antiretroviral clinic in Ghana. METHODS: We examined serum levels of high sensitivity CRP (hsCRP), interleukin-6 (IL-6), interleukin- 18(IL-18), and tumor necrosis factor-α (sTNFR1 and sTNFR2) from 40 HIV infected patients. Kruskal-Wallis Test was used to examine the differences in markers of systemic inflammation according to the types of ART medication taken. We then utilized generalized additive models (GAM) with non-linear function to examine the association between ART and markers of systemic inflammation after adjusting for potential confounders. RESULTS: Overall, 30 (75.0%) of the participants received ART and 35 (85%) were female. Kruskal- Wallis Test revealed no significant differences in the markers of systemic inflammation among the three categories of ART (none, AZT, 3TC, EFV/NVP, and TDF, 3TC/FTC, EFV/NVP). In the multivariable- adjusted GAM model, we found a significant but non-linear association between time since diagnosis and CRP levels (p=0.006). CONCLUSION: Although the relatively small sample size limits the scope of the study's findings, these results suggest that individuals on ART need to be screened periodically for the development of chronic conditions. This line of investigation has the potential to influence treatment and clinical guidelines that will improve the quality of care for HIV-infected patients.

Effect of Size and Drying Time on the Rehydration and Sensory Properties of Freeze-Dried Snails (Achatina achatina).

Snails, a delicacy in most tropical communities, are highly perishable and seasonal. Employed preservative methods are highly temperature dependent, adversely affecting their nutritional value and sensory properties. This study was aimed at determining the effect of size and drying time on the rehydration and sensory properties of freeze-dried snails. Snails were sized into three categories with average weights: 7.59 g (quarter-sized), 14.41 g (half-sized), and 30.71 g (whole), and freeze-dried for 15, 20, and 25 h. The moisture content and percent rehydration of the dried samples were determined by standard methods and sensory properties assessed by an in-house panel of 30 using a 5-point hedonic scale. The moisture content of the fresh and freeze-dried samples ranged from 65.80 to 75.20% and 3.25 to 10.24%, respectively. Freeze-dried samples had higher percent rehydration (27 to 102%) than the control; smoked snails (21 to 32%). Size had a significant (P < 0.05) effect on the rehydration ability of the samples with the half-sized and freeze-dried for 15 h samples having the highest. The freeze-dried samples generally had higher consumer preference than the control in all attributes assessed. The findings show that freeze-drying snails (approximate weight of 14.4 g) for 15 h could be a consumer-preferred alternative preservative method for extending the shelf life of snails.

Significant Induction of Soluble TNFR2 Compared with TNFR1 in Serum Samples of HIV Patients with or without Antiretroviral Medication.

BACKGROUND: Tumor necrosis factor and its receptors (sTNFR1 and sTNFR2) have been implicated in many infectious diseases. Identification of the key receptor (sTNFR1 or sTNFR2) which drives the immunopathogenesis of HIV infection is crucial in developing adjunctive therapy for HIV. OBJECTIVE: This study determined the expression levels of sTNFR1 and sTNFR2 in antiretroviral therapy (ART) - experienced and naïve HIV patients. METHODS: A total of 40 HIV patients comprising 30 with ART and 10 without ART were enrolled from the Pantang Hospital located in the Greater Accra Region of Ghana for data and blood collection. Serum concentrations of sTNFR1 and sTNFR2 were determined by ELISA. Mann- Whitney U test was used to examine differences in serum levels of sTNFR1 and sTNFR2 between patients on ART and ART naïve patients. Wilcoxon Signed-Rank test was performed to determine the difference between sTNFR1 and sTNFR2, and Kruskal Wallis test was conducted to compare the effect of different antiretroviral drugs on the levels of sTNFR1 and sTNFR2. P< 0.05 was considered statistically significant. RESULTS: A Wilcoxon Signed-Ranks Test indicated serum levels of sTNFR2 was statistically significantly higher than sTNFR1 (Z=-5.51; p<0.001). Levels of sTNFR1 and sTNFR2 did not differ by ART status U =91.00 (Z = -1.84), p = 0.065 and U = 131.50 (Z = -0.58, p =0.560), respectively. There were not significant differences in levels of TNFR2 H(2) = 1.86, p=0.395 and sTNFR1 (H (2) = 4.37, p=0.113 across different ART combinations. CONCLUSION: Compared to sTNFR1, the level of sTNFR2 is significantly increased during HIV infection irrespective of ART status. The high sTNFR2 level is not associated with antiretroviral drugs and may be another potential target for therapeutic development. This is the first study of sTNFRs in African population.

Symptoms of Toxicity and Plasma Cytochrome c Levels in Human Immunodeficiency Virus-infected Patients Receiving Anti-retroviral Therapy in Ghana: A Cross-sectional Study.

BACKGROUND: Side effects and toxicity have posed a threat to the positive contribution of Antiretroviral Therapy (ART) in the management of human immunodeficiency virus (HIV) infection and Acquired Immune Deficiency Syndrome (AIDS). Symptoms of mitochondrial toxicity including myopathy, pancreatitis, hyperlipidaemia and lactic acidosis are found among HIVinfected patients on ART. To date, there is not a reliable biomarker for monitoring ART-related mitochondrial toxicity. Plasma level of Cytochrome c (Cyt-c) has been proposed as a potential biomarker for ART-related toxicity due to its strong association with apoptosis. OBJECTIVE: The present study assessed toxicity and level of plasma Cyt-c among HIV-infected patients receiving ART in Ghana. METHODS: A total of eighty (80) HIV patients were recruited into the study. Demographic data were obtained from personal interview and medical records. Plasma samples were screened for toxicity from sixty (60) participants due to limited resources, and plasma Cyt-c levels were determined using ELISA. Data were analyzed using Stata version 13. RESULTS: Out of the 60 participants, 11 (18.3%) were found with symptoms of myopathy, 12 (20%) with pancreatitis, 21 (35%) with hyperlipidaemia and 36 (60%) with at least one of the symptoms. The concentration of plasma Cyt-c was higher (0.122 ng/ml) in patients with toxicity than in those without toxicity (0.05 ng/ml), though the difference was not statistically significant (p = 0.148). There was a weak correlation between plasma Cyt-c level and duration of ART (Spearman rho = 0.02, p = 0.89). CONCLUSION: This study, therefore, demonstrated a high prevalence of ART-related toxicity and high levels of Cyt-c in HIV-infected patients in support of the argument that plasma Cyt-c levels are potential biomarkers for determining ART-related toxicity in HIV patients.

Molecular epidemiology and mechanisms of antibiotic resistance in Enterococcus spp., Staphylococcus spp., and Streptococcus spp. in Africa: a systematic review from a One Health perspective.

A systematic review of antibiotic-resistant Gram-positive bacteria in Africa from a One Health perspective is lacking. Here, we report result from a search for English-language articles on the resistance mechanisms and clonality of Gram-positive bacteria in Africa between 2007 and 2019 reported in PubMed, Web of Science, ScienceDirect, and African Journals OnLine; 172 studies from 22 different African countries were identified. Resistance genes, such as mecA, erm(B), erm(C), tet(M), tet(K), tet(L), vanB, vanA, vanC, and tet(O), were found to be common. Staphylococcus spp., Enterococcus spp., and Streptococcus spp. were the main species reported by the studies, with clones such as Staphylococcus aureus ST5 (n = 218 isolates), ST8 (n = 127 isolates), ST80 (n = 133 isolates), and ST88 (n = 117 isolates), and mobile genetic elements such as IS16 (n = 28 isolates), IS256 (n = 96), Tn916 (n = 107 isolates), and SCCmec (n = 4437 isolates) identified. SCCmec IV (n = 747 isolates) was predominant, followed by SCCmec III (n = 305 isolates), SCCmec II (n = 163 isolates), SCCmec V (n = 135 isolates), and SCCmec I (n = 79 isolates). Resistance to penicillin (n = 5926 isolates), tetracycline (n = 5300 isolates), erythromycin (n = 5151 isolates), rifampicin (n = 3823 isolates), gentamycin (n = 3494 isolates), sulfamethoxazole/trimethoprim (n = 3089 isolates), and ciprofloxacin (n = 2746 isolates) was common in most reports from 22 countries. Clonal dissemination of resistance across countries and between humans, animals, and the environment was observed. Resistance rates ranged from 1.4% to 100% for 15 of the studies; 10 were One Health-related studies. Strict infection control measures, antimicrobial stewardship, and periodic One Health epidemiological surveillance studies are needed to monitor and contain the threat of increasing antibiotic resistance in Africa.

Structure determination of the CAMP factor of Streptococcus agalactiae with the aid of an MBP tag and insights into membrane-surface attachment.

CAMP factor is a unique α-helical bacterial toxin that is known for its co-hemolytic activity in combination with staphylococcal sphingomyelinase. It was first discovered in the human pathogen Streptococcus agalactiae (also known as group B streptococcus), but homologous genes have been found in many other Gram-positive pathogens. In this study, the efforts that led to the determination of the first structure of a CAMP-family toxin are reported. Initially, it was possible to produce crystals of the native protein which diffracted to near 2.45 Šresolution. However, a series of technical obstacles were encountered on the way to structure determination. Over a period of more than five years, many methods, including selenomethionine labeling, mutations, crystallization chaperones and heavy-atom soaking, were attempted, but these attempts resulted in limited progress. The structure was finally solved using a combination of iodine soaking and molecular replacement using the crystallization chaperone maltose-binding protein (MBP) as a search model. Analysis of native and MBP-tagged CAMP-factor structures identified a conserved interaction interface in the C-terminal domain (CTD). The positively charged surface may be critical for binding to acidic ligands. Furthermore, mutations on the interaction interface at the CTD completely abolished its co-hemolytic activities. This study provides novel insights into the mechanism of the membrane-permeabilizing activity of CAMP factor.

Sialic acid facilitates binding and cytotoxic activity of the pore-forming Clostridium perfringens NetF toxin to host cells.

NetF-producing type A Clostridium perfringens is an important cause of canine and foal necrotizing enteritis. NetF, related to the ß-sheet pore-forming Leukocidin/Hemolysin superfamily, is considered a major virulence factor for this disease. The main purpose of this work is to demonstrate the pore-forming activity of NetF and characterize the chemical nature of its binding site. Electron microscopy using recombinant NetF (rNetF) confirmed that NetF is able to oligomerize and form large pores in equine ovarian (EO) cell membranes and sheep red blood cells. These oligomeric pores appear to be about 4-6 nm in diameter, and the number of oligomer subunits to vary from 6 to 9. Sodium periodate treatment rendered EO cells non-susceptible to NetF, suggesting that NetF binding requires cell surface carbohydrates. NetF cytotoxicity was also inhibited by a lectin that binds sialic acid, by sialidase, and by free sialic acid in excess, all of which clearly implicate sialic acid-containing membrane carbohydrates in NetF binding and/or toxicity for EO cells. Binding of NetF to sheep red blood cells was not inhibited by the gangliosides GM1, GM2 and GM3, nor did the latter promote membrane permeabilization in liposomes, suggesting that they do not constitute the cellular receptors. In contrast, treatment of EO cells with different proteases reduced their susceptibility to NetF, suggesting that the NetF receptor is a sialic acid-containing glycoprotein.

Crystal structure of the Streptococcus agalactiae CAMP factor provides insights into its membrane-permeabilizing activity.

Streptococcus agalactiae is an important human opportunistic pathogen that can cause serious health problems, particularly among newborns and older individuals. S. agalactiae contains the CAMP factor, a pore-forming toxin first identified in this bacterium. The CAMP reaction is based on the co-hemolytic activity of the CAMP factor and is commonly used to identify S. agalactiae in the clinic. Closely related proteins are present also in other Gram-positive pathogens. Although the CAMP toxin was discovered more than a half century ago, no structure from this toxin family has been reported, and the mechanism of action of this toxin remains unclear. Here, we report the first structure of this toxin family, revealing a structural fold composed of 5 + 3-helix bundles. Further analysis by protein truncation and site-directed mutagenesis indicated that the N-terminal 5-helix bundle is responsible for membrane permeabilization, whereas the C-terminal 3-helix bundle is likely responsible for host receptor binding. Interestingly, the C-terminal domain inhibited the activity of both full-length toxin and its N-terminal domain. Moreover, we observed that the linker region is highly conserved and has a conserved DLXXXDXAT sequence motif. Structurally, this linker region extensively interacted with both terminal CAMP factor domains, and mutagenesis disclosed that the conserved sequence motif is required for CAMP factor's co-hemolytic activity. In conclusion, our results reveal a unique structure of this bacterial toxin and help clarify the molecular mechanism of its co-hemolytic activity.

Genetic analysis and association of simple sequence repeat markers with storage root yield, dry matter, starch and ß-carotene content in sweetpotato.

Molecular markers are needed for enhancing the development of elite sweetpotato (Ipomoea batatas (L.) Lam) cultivars with a wide range of commercially important traits in sub-Saharan Africa. This study was conducted to estimate the heritability and determine trait correlations of storage root yield, dry matter, starch and ß-carotene content in a cross between 'New Kawogo' × 'Beauregard'. The study was also conducted to identify simple sequence repeat (SSR) markers associated with these traits. A total of 287 progeny and the parents were evaluated for two seasons at three sites in Uganda and genotyped with 250 SSR markers. Broad sense heritability (H2) for storage root yield, dry matter, starch and ß-carotene content were 0.24, 0.68, 0.70 and 0.90, respectively. Storage root ß-carotene content was negatively correlated with dry matter (r = -0.59, P < 0.001) and starch (r = -0.93, P < 0.001) content, while storage root yield was positively correlated with dry matter (r = 0.57, P = 0.029) and starch (r = 0.41, P = 0.008) content. Through logistic regression, a total of 12, 4, 6 and 8 SSR markers were associated with storage root yield, dry matter, starch and ß-carotene content, respectively. The SSR markers used in this study may be useful for quantitative trait loci analysis and selection for these traits in future.

The safety of influenza vaccines in children: An Institute for Vaccine Safety white paper.

Most influenza vaccines are generally safe, but influenza vaccines can cause rare serious adverse events. Some adverse events, such as fever and febrile seizures, are more common in children than adults. There can be differences in the safety of vaccines in different populations due to underlying differences in genetic predisposition to the adverse event. Live attenuated vaccines have not been studied adequately in children under 2 years of age to determine the risks of adverse events; more studies are needed to address this and several other priority safety issues with all influenza vaccines in children. All vaccines intended for use in children require safety testing in the target age group, especially in young children. Safety of one influenza vaccine in children should not be extrapolated to assumed safety of all influenza vaccines in children. The low rates of adverse events from influenza vaccines should not be a deterrent to the use of influenza vaccines because of the overwhelming evidence of the burden of disease due to influenza in children.

mol2chemfig, a tool for rendering chemical structures from molfile or SMILES format to LATE X code.

: Displaying chemical structures in LATE X documents currently requires either hand-coding of the structures using one of several LATE X packages, or the inclusion of finished graphics files produced with an external drawing program. There is currently no software tool available to render the large number of structures available in molfile or SMILES format to LATE X source code. We here present mol2chemfig, a Python program that provides this capability. Its output is written in the syntax defined by the chemfig TE X package, which allows for the flexible and concise description of chemical structures and reaction mechanisms. The program is freely available both through a web interface and for local installation on the user's computer. The code and accompanying documentation can be found at http://chimpsky.uwaterloo.ca/mol2chemfig.