Bioconversion of lignocellulosic waste from selected dumping sites in Dar es Salaam,Tanzania

The poor management of solid wastes in Tanzania urban centers is a chronic problem that has increasingly become a source of environmental pollution. Bioconversion offers a cheap and safe method of not only disposing these wastes, but also it has the potential to convert lignocellulosic wastes into usable forms such as reducing sugars that could be used as food. This paper reports a preliminary study on the physical characteristics, acid pretreatment, saccharification by cellulase from Trichoderma reesei and fermentation by Saccharomyces cerevisiae of the lignocellulosic component of the solid wastes collected from various dumping sites located in Kinondoni Municipality, Dar es Salaam city. The results showed that overall, the lignocellulosic component constitute about 50% of solid wastes dumped in the study areas. Maximum production of reducing sugars was obtained after 6 h of saccharification while highest concentrations of bioethanol were achieved after 48 h of fermentation. Microbial bioconversion of lignocellulose component yielded up to 21% bioethanol.     

Continuous production of lignin-degrading enzymes by Bjerkandera adusta immobilized on polyurethane foam

Continuous production of lignin-degrading enzymes by Bjerkandera adusta immobilized on polyurethane foam gave maximum activities of 220 U lignin peroxidase ml^–1, 150 U manganese peroxidase ml^–1, 50 U laccase ml^–1 and 6.2 U protease ml^–1 at the retention time of 24 h for 60 days. Protease secretion destabilized the produced lignin peroxidase, manganese peroxidase and laccase.     

Comparative genomics of Bifidobacterium species isolated from marmosets and humans

The genus Bifidobacterium is purported to have beneficial consequences for human health and is a major component of many gastrointestinal probiotics. Although species of Bifidobacterium are generally at low relative frequency in the adult human gastrointestinal tract, they can constitute high proportions of the gastrointestinal communities of adult marmosets. To identify genes that might be important for the maintenance of Bifidobacterium in adult marmosets, ten strains of Bifidobacterium were isolated from the feces of seven adult marmosets, and their genomes were sequenced. There were six B. reuteri strains, two B. callitrichos strains, one B. myosotis sp. nov. and one B. tissieri sp. nov. among our isolates. Phylogenetic analysis showed that three of the four species we isolated were most closely related to B. bifidum, B. breve and B. longum, which are species found in high abundance in human infants. There were 1357 genes that were shared by at least one strain of B. reuteri, B. callitrichos, B. breve, and B. longum, and 987 genes that were found in all strains of the four species. There were 106 genes found in B. reuteri and B. callitrichos but not in human bifidobacteria, and several of these genes were involved in nutrient uptake. These pathways for nutrient uptake appeared to be specific to Bifidobacterium from New World monkeys. Additionally, the distribution of Bifidobacterium in fecal samples from captive adult marmosets constituted as much as 80% of the gut microbiome, although this was variable between individuals and colonies. We suggest that nutrient transporters may be important for the maintenance of Bifidobacterium during adulthood in marmosets.     

Forearm compartment syndrome: anatomical analysis of surgical approaches to the deep space

Forearm compartment syndrome is a surgical emergency that usually requires release of the superficial muscle compartments. In some clinical situations it is imperative to also explore the deep muscle compartments. There are no anatomical guides for surgical exploration of the deep compartments that would minimize collateral damage to surrounding vessels, nerves, and muscles. Surgical injury in the setting of ischemia, especially vascular injury, compounds the tissue damage that has already occurred. The authors evaluated four surgical approaches (three volar and one dorsal) to the deep forearm by performing detailed anatomical dissections on 10 embalmed and plastinated cadavers. They used a scoring system to rate the approaches for their ability to visualize the deep space without causing iatrogenic injury to superficial muscles, arteries, and nerves. In the volar forearm, an ulnar approach to the deep space is simple, causes the least iatrogenic surgical injury, and provides access to the deep volar forearm structures. The plane of dissection is between the flexor carpi ulnaris and the flexor digitorum superficialis. Dividing one or two distal segmental branches of the ulnar artery to the distal flexor digitorum superficialis exposes the pronator quadratus. Lifting the ulnar neurovascular bundle with the flexor digitorum superficialis in the middle third of the forearm exposes the flexor digitorum profundus and the flexor pollicis longus. This approach to the deep space requires no sharp dissection. In the dorsal forearm, a midline approach between the extensor digitorum communis and the extensor carpi radialis brevis is simple and safe.     

Anaerobic fermentation of woody biomass treated by various methods

Anaerobic fermentation was attempted to produce methane from the wood chip (Eucalyptus globulus). By the pretreatment of the wood chip using hot water with high temperature, NaOH, and steam explosion, the production of methane gas was enhanced. The pretreatment using steam explosion resulted in more amount of methane gas produced than the treatment using either hot water or 1% (w/w) NaOH with high temperature, and the steam explosion at a steam pressure of 25 atm and a steaming time of 3 min was the most effective for the methane production. The amount of methane gas produced depended on the ratio of weight of Klason lignin, a high molecular weight lignin, in the treated wood chip.     

Sanje mangabey Cercocebus sanjei kills an African crowned eagle Stephanoaetus coronatus

We present the first ever reported observations of a hunting African crowned eagle Stephanoaetus coronatus being killed by a primate, in the Udzungwa Mountains of south-central Tanzania. An adult female eagle launched an attack on a young Sanje mangabey Cercocebus sanjei who was feeding in a tree, but was intercepted and bitten by an adult mangabey who was feeding nearby. The adult mangabey and the eagle then fell together 25 m to the forest floor below. The eagle subsequently died from her injuries, while the mangabey escaped and is thought to have survived. This rare event is briefly discussed in the context of previous accounts of primate-crowned eagle interactions.     

Abundance of Diurnal Primates in Mwanihana Forest, Udzungwa Mountains, Tanzania

Many individual researchers have used line transect counts to estimate forest primate abundance. They have devoted less attention to the interpretation of line transect data obtained by several observers, as is often the case in long-term monitoring programs. We present primate relative abundance data that 5 observers collected over 6 yr (not continuous) along 4 different transects each 4 km long in the Mwanihana Forest, Udzungwa Mountains National Park, Tanzania. Total distance walked during transect repetitions is ca. 700 km. The species we saw most frequently was the endemic Udzungwa red colobus Procolobus gordonorum (mean 0.59 groups/km walked), followed by the Angolan black-and-white colobus Colobus angolensis (0.43 groups/km) and Sykes’s monkey Cercopithecus mitis (0.35 groups/km). We sighted the endemic Sanje mangabey Cercocebus galeritus sanjei and the yellow baboon Papio cynocephalus infrequently, the latter being confined to the deciduous forest parts of the transects. We analyzed sighting frequency by gross habitat type, transect, season, and observer. Interobserver differences in the relative abundance of each species were moderate and the few cases of significant variations were due to discordance of only 1 observer from the others. Estimated distances of primate group sightings differ significantly among observers, thus preventing us from deriving estimates of absolute density. Frequency distributions of distance-class intervals are not significantly different among observers, which may indicate gross interobserver consistency in the width of the area sampled. We conclude that unless consistency in data collection is checked, as we did for 2 observers who collected data simultaneously, potential interobserver differences remain an underlying source of variance in the results that cannot be separated from other sources of variance.     

Shifts in the distributional ranges of <Emphasis Type="Italic">Boophilus</Emphasis> ticks in Tanzania: evidence that a parapatric boundary between <Emphasis Type="Italic">Boophilus microplus</Emphasis> and <Emphasis Type="Italic">B. decoloratus</Emphasis> follows climate gradients

Based on a national tick survey conducted in Tanzania between 1998 and 2001, predictive maps of tick distribution for B. microplus and B. decoloratus were computed and compared with historical maps that originated about 40 years ago. The new data collected showed that except for extremely cold and dry areas B. microplus has extended its distribution range and is now present in all the northern regions of Tanzania, and that high suitability is currently recorded for most of the previously non-occupied areas. In contrast, B. decoloratus, once abundant in Tanzania, has largely retreated to highlands in north and central Tanzania and several other high-altitude refuges. Geostatistical analysis revealed a dissimilar character of distribution for the two species at a local and regional scale, as well as an antagonistic relationship between them in a spatial context. The Tanzania data suggest that an equilibrium phase with a stable parapatric boundary that follows a climate gradient has been achieved. The zone of overlap in the distribution ranges of B. microplus and B. decoloratus is characterized by a decreased infestation rate as well as mutual exclusion on infested cattle. This finding matches studies on parapatry with hybrid zones, where the latter zones that separate species tend to rest in density troughs. Analysis of the Tanzania data shows that the critical factor for the advance of B. microplus and the retreat of B. decoloratus is associated with the 58 mm isohyet and the 22–23°C isotherm and indicates a well developed higher-temperature tolerance for B. microplus. It can be anticipated that climate changes may enhance the spread of B. microplus and consequently Babesia bovis into new areas of the African continent.     

Biodegradation of endocrine-disrupting phenolic compounds using laccase followed by activated sludge treatment

Endocrine-disrupting phenolic compounds in the water were degraded by laccase fromTrametes sp. followed by activated sludge treatment. The effect of temperature on the degradation of phenolic compounds and the production of organic compounds were investigated using endocrine-disrupting chemicals such as bisphenol A, 2,4-dichlorophenol, and diethyl phthalate. Bisphenol A and 2,4-dichlorophenol disappeared completely after the laccase treatment, but no disappearance of diethyl phthalate was observed. The Michaelis-Menten type equation was proposed to represent the degradation rate of bisphenol A by the lacasse under various temperatures. After the laccase treatment of endocrine-disrupting chemicals, the activated sludge treatment was attempted and it could convert about 85 and 75% of organic compounds produced from bisphenol A and 2,4-dichlorophenol into H₂O and CO₂, respectively.     

Resiniferatoxin binds to the capsaicin receptor (TRPV1) near the extracellular side of the S4 transmembrane domain

The capsaicin receptor (TRPV1) is a nonselective cation channel that is activated in nociceptors by several painful stimuli, and hence TRPV1 antagonists could represent a novel class of analgesic compounds. Resiniferatoxin (RTX), a potent agonist of TRPV1, and iodoresiniferatoxin (I-RTX), a potent antagonist of TRPV1, both bind with higher affinity to the rat TRPV1 (rTRPV1) than the human (hTRPV1) isoform. To identify the structural features responsible for this difference in affinity, [(3)H]RTX binding to chimeras between hTRPV1 and rTRPV1 was characterized. The "sensor" region within the transmembrane domain (S1-S4) was found to determine [(3)H]RTX binding affinity. All 16 different residues in this region were systematically substituted in hTRPV1 with rTRPV1 residues. A single mutation in the S4 membrane domain of hTRPV1, L547M, caused a 30-fold increase in [(3)H]RTX affinity whereas the inverse mutation in rTRPV1, M547L, caused a 30-fold decrease in affinity for [(3)H]RTX, and several other agonists and antagonists were similarly affected by these mutations. TRPV1 channels with mutations at position 547 were expressed in oocytes, and the relative response to RTX followed a pattern similar to that seen with [(3)H]RTX binding. These data suggest a model where Met-547 in the S4 domain of TRPV1 forms a binding pocket with Tyr-511 in the S3 domain. This model places RTX near the sensor domain thought to move during the gating process and should help to guide further work designed to understand the gating mechanisms of TRPV1 channels based on comparisons between the agonist RTX and the related competitive antagonist I-RTX.