Pectinolytic activities of pectinase produced by some bacterial isolates cultured from deteriorating fruits

Microbially derived pectinases have been shown to have due advantages over those produced from other sources because of the ease in manipulating the microorganisms to increase yield. The study was undertaken to determine the pectinolytic activities of pectinase produced by some bacterial isolates cultured from deteriorating fruits under submerged fermentation. Deteriorating oranges and grapefruits were collected and surfaced sterilized. Thereafter, 1 g of each sample was homogenized and transferred into 10ml sterile distilled water. The suspensions were agitated, streaked onto nutrient agar and incubated at 37 oC for 24 h. The isolates were screened for pectinolytic activities and identified using standard protocols. The specific activities of the enzyme and the physicochemical factors were analysed. The isolates identified were Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Klebsiella aerogenes isolates. The specific activities of pectinase produced by the isolates were between 26.40- 52.27 U/ml. The isolates reacted differently to the different substrates used. The optimum temperature for the activity of pectinase observed from the isolates was 50 oC and the pH varied between pH 4 and 8. Sodium azide at 1 mM and EDTA at 10 mM were observed to inhibit pectinase activity in all the isolates. The isolates showed promising potential for pectinase production under optimal physicochemical conditions.Keywords: Bacteria, Pectinase, deteriorating fruits, submerged fermentation, physicochemical parameter

HIV-1 recombinants with multiple parental strains in low-prevalence, remote regions of Cameroon: Evolutionary relics?

<p>Abstract</p> <p>Background</p> <p>The HIV pandemic disseminated globally from Central West Africa, beginning in the second half of the twentieth century. To elucidate the virologic origins of the pandemic, a cross-sectional study was conducted of the genetic diversity of HIV-1 strains in villagers in 14 remote locations in Cameroon and in hospitalized and STI patients. DNA extracted from PBMC was PCR amplified from HIV(+) subjects. Partial <it>pol </it>amplicons (N = 164) and nearly full virus genomes (N = 78) were sequenced. Among the 3956 rural villagers studied, the prevalence of HIV infection was 4.9%; among the hospitalized and clinic patients, it was 8.6%.</p> <p>Results</p> <p>Virus genotypes fell into two distinctive groups. A majority of the genotyped strains (109/164) were the circulating recombinant form (CRF) known to be endemic in West Africa and Central West Africa, CRF02_AG. The second most common genetic form (9/164) was the recently described CRF22_01A1, and the rest were a collection of 4 different subtypes (A2, D, F2, G) and 6 different CRFs (-01, -11, -13, -18, -25, -37). Remarkably, 10.4% of HIV-1 genomes detected (17/164) were heretofore undescribed unique recombinant forms (URF) present in only a single person. Nearly full genome sequencing was completed for 78 of the viruses of interest. HIV genetic diversity was commonplace in rural villages: 12 villages each had at least one newly detected URF, and 9 villages had two or more.</p> <p>Conclusions</p> <p>These results show that while CRF02_AG dominated the HIV strains in the rural villages, the remainder of the viruses had tremendous genetic diversity. Between the trans-species transmission of SIV_cpzand the dispersal of pandemic HIV-1, there was a time when we hypothesize that nascent HIV-1 was spreading, but only to a limited extent, recombining with other local HIV-1, creating a large variety of recombinants. When one of those recombinants began to spread widely (i.e. became epidemic), it was recognized as a subtype. We hypothesize that the viruses in these remote Cameroon villages may represent that pre-epidemic stage of viral evolution.</p

TRADITIONAL MEDICINE: PAST, PRESENT AND FUTURE RESEARCH AND DEVELOPMENT PROSPECTS AND INTEGRATION IN THE NATIONAL HEALTH SYSTEM OF CAMEROON.

Traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being. In the last decade traditional medicine has become very popular in Cameroon, partly due to the long unsustainable economic situation in the country. The high cost of drugs and increase in drug resistance to common diseases like malaria, bacteria infections and other sexually transmitted diseases has caused the therapeutic approach to alternative traditional medicine as an option for concerted search for new chemical entities (NCE). The World Health Organisation (WHO) in collaboration with the Cameroon Government has put in place a strategic platform for the practice and development of TM in Cameroon. This platform aims at harmonizing the traditional medicine practice in the country, create a synergy between TM and modern medicine and to institutionalize a more harmonized integrated TM practices by the year 2012 in Cameroon. An overview of the practice of TM past, present and future perspectives that underpins the role in sustainable poverty alleviation has been discussed. This study gives an insight into the strategic plan and road map set up by the Government of Cameroon for the organisational framework and research platform for the practice and development of TM, and the global partnership involving the management of TM in the country

A comparative study of pectinolytic enzyme production by Bacillus species

The economic and ecological function of pectinase enzymes in industries is gaining much attention with the need of highly productive strains of microorganisms to reduce production cost. The present investigation is a comparative evaluation of Bacillus sp. pectinases. The three isolates isolated from agro-waste, Bacillus stearothermophilus, Bacillus cereus and Bacillus subtilis, showed very high pectinase activities with pectin as the substrate. The three isolates also showed varying degree of preference for banana peels and wheat bran but their activity towards orange peel was very low compared to other substrate. The effect of temperature on the pectinase of the three isolates showed that B. stearothermophilus had optimum temperature at 60°C while B. cereus and B. subtilis both showed optimum activity at 50°C. On the effect of pH, B. stearothermophilus, B. cereus and B. subtilis showed optimum pectinase activities at pH 7.5, 8.0 and 9.0, respectively. Metal ions enhanced the activity of pectinase produced by the three isolates. The study exhibited that B. stearothermophilus gave the most pectinase activity, optimum temperature and a moderate alkaline pH, possibly making it a better source for industrial purpose.Key words: Pectinase, enzymes, pectin, bacteria, Bacillus species

A study on 3-mercaptopyruvate sulphurtransferase (3-MST) produced under submerged fermentation by Pseudomonas putida KT12440 isolated from an industrial effluent

Effluents from an Iron and Steel company were collected, the cyanide level was determined and screening for cyanide degrading bacterial isolates on modified Bushnell Haas agar media was done. The amount of cyanide present in the industrial effluent was 1.06 mg/L. The 16S rRNA gene sequencing identified Pseudomonas putida KT12440 as the isolate with highest activity for 3-MST production. The cell growth was optimal at 30 h incubation time and a decrease in cell growth was observed with the increase of incubation time after the optimum. The highest 3-MST production was observed when mannitol was used as the sole carbon source while fructose is the least source of carbon. Casein showed the highest production for 3-MST when used as an alternative nitrogen source while NH4NO3 was the least. The optimal pH for 3-MST production was 9.0 and a sharp decrease in the enzyme production was observed thereafter. The incubation temperature for the production of 3-MST in the culture medium peaked at 30ºC and a sharp decline in temperature was observed afterward. The bacterial isolate screened in this study showed degradation potential that can be harnessed to remediate effluents containing cyanide. Keywords: Cyanide, Industrial Effluent, Pseudomonas putida KT12440, 3-MS

Lipid peroxidation and total cholesterol in HAART-naïve patients infected with circulating recombinant forms of human immunodeficiency virus type-1 in Cameroon.

BackgroundHIV infection has commonly been found to affect lipid profile and antioxidant defense.ObjectivesTo determine the effects of Human Immunodeficiency Virus (HIV) infection and viral subtype on patient's cholesterol and oxidative stress markers, and determine whether in the absence of Highly Active Antiretroviral Therapy (HAART), these biochemical parameters could be useful in patient's management and monitoring disease progression in Cameroon. For this purpose, we measured total cholesterol (TC), LDL cholesterol (LDLC), HDL cholesterol (HDLC), total antioxidant ability (TAA), lipid peroxidation indices (LPI), and malondialdehyde (MDA) in HIV negative persons and HIV positive HAART-naïve patients infected with HIV-1 group M subtypes.MethodsWe measured serum TC, LDLC, HDLC, plasma MDA, and TAA concentrations, and calculated LPI indices in 151 HIV-positive HAART-naïve patients and 134 seronegative controls. We also performed gene sequence analysis on samples from 30 patients to determine the effect of viral genotypes on these biochemical parameters. We also determined the correlation between CD4 cell count and the above biochemical parameters.ResultsWe obtained the following controls/patients values for TC (1.96±0.54/1. 12±0. 48 g/l), LDLC (0. 67±0. 46/0. 43±0. 36 g/l), HDLC (105. 51±28. 10/46. 54±23. 36 mg/dl) TAA (0. 63±0. 17/0. 16±0. 16 mM), MDA (0. 20±0. 07/0. 41±0. 10 µM) and LPI (0. 34±0. 14/26. 02±74. 40). In each case, the difference between the controls and patients was statistically significant (pConclusionThese results show that HIV infection in Cameroon is associated with significant decrease in TAA, LDLC, HDLC and TC, and increased MDA concentration and LPI indices which seem to be linked to the severity of HIV infection as assessed by CD4 cell count. The data suggests increased oxidative stress and lipid peroxidation in HIV-infected patients in Cameroon, and an influence of CRFs on TC and MDA levels

Deforestation, hunting and the ecology of microbial emergence

Understanding how novel microbes enter into the human population is perhaps the fundamental goal of the study of emerging infectious diseases (EID). The frequency at which microbes will emerge is determined by the diversity of microbes present in the environment, the level of contact between a potential host and this microbial diversity and the susceptibility of the novel host to infection. While a range of microbial media exist, including soils, plants and animals, the greatest emergence risks come through contact with media, such as wild vertebrates, that share susceptibility characteristics with humans and live in regions of high microbial diversity. Lowland tropical forests provide a rich environment for emergence due to their combination of high vertebrate and microbial biodiversity. Human activities that occur in lowland tropical forests, such as ecotourism, logging, and the hunting of wild vertebrates have the potential to increase the frequency of microbial emergence. Of these and other activities considered, hunting and the processing of bushmeat, particularly from nonhuman primates, involve the greatest level of risk for the transmission of microbes. While human hunting in lowland tropical forests poses a serious threat for microbial emergence, it is by no means alone among contemporary human behaviors in doing so, sharing risk characteristics with activities as diverse as lab microbiology, wildlife veterinary work, and modern food production practices

Near-full-length genome sequencing of divergent African HIV type 1 subtype F viruses leads to the identification of a new HIV type 1 subtype designated K

We recently reported a high divergence among African subtype F strains. Three well-separated groups (F1, F2, and F3) have been shown based on the phylogenetic analysis of the p24 gag and envelope sequences with genetic distances similar to those observed for known subtypes. In this study, we characterized the near-full-length genomes of two strains from epidemiological unlinked individual belonging to each of the subgroups : F1 (96FR-MP411), F2 (95CM-MP255 and 95CM-MP257), and F3 (96CM-MP535 and 97ZR-EQTB11). Phylogenetic analysis of the near-full-length sequences and for each of the genes separately showed the same three groups, supported by high bootstrap values. Diversity plotting, BLAST subtyping, and bootstrap plotting confirmed that the divergent F strains correspond to nonrecombinant viruses. The divergence between F1 and F2 is consistently lower than that seen in any other intersubtype comparison, with the exception of subtypes B and D. Based on all the different analyses, we propse to divide subtype F into two subclades, with F1 gathering the known subtype strains from Brazil and Finland, and our African strain (96FR-MP411), and F2 containing the 95CM-MP255 and 95CM-MP257 strains from Cameroon. The F3 strains, 97ZR-EQTB11 from the Democratic Republic of Congo and 96CM-MP535 from Cameroon, meet the criteria of a new subtype designated as K. The equidistance of subtype K to the other subtypes of HIV-1 suggests that this subtype existed as long as the others, the lower distance between B and D, and between F1 and F2 suggest a more recent subdivision for these latter strains. (Résumé d'auteur