Visceral Leishmaniasis and HIV Coinfection in East Africa

Visceral Leishmaniasis (VL) is an important protozoan opportunistic disease in HIV patients in endemic areas. East Africa is second to the Indian subcontinent in the global VL caseload and first in VL-HIV coinfection rate. Because of the alteration in the disease course, the diagnostic challenges, and the poor treatment responses, VL with HIV coinfection has become a very serious challenge in East Africa today. Field experience with the use of liposomal amphotericin B in combination with miltefosine, followed by secondary prophylaxis and antiretroviral drugs, looks promising. However, this needs to be confirmed through clinical trials. Better diagnostic and follow-up methods for relapse and prediction of relapse should also be looked for. Basic research to understand the immunological interaction of the two infections may ultimately help to improve the management of the coinfection.     

Inter- and intra-population genetic divergence of East Asian cattle populations: focusing on Korean cattle

In order to facilitate the on-going cattle conservation and improvement programs in Korea, we examined genetic relationships among East Asian cattle, focusing on Korean native cattle, using complete mitochondrial DNA control region sequences. In total, 67 haplotypes were discriminated by 97 variable sites in East Asian cattle. Of the variable sites, 35 represented singleton variable sites and 62 were parsimony informative sites. For Korean cattle, 30 haplotypes were discriminated by 40 variable sites. The variable sites identified in this study correspond to transition or transversion point mutations. Inter-populations genetic distance varied from 0.004 to 0.052 for East Asian cattle populations. The genetic divergence observed between Korean Brown and Jeju Black (0.004) was among the lowest. The Mongolian cattle were slightly divergent from other East Asian cattle populations studied. The network analysis uncovered that Jeju Black and Yunbian samples represented the possible ancestral Haplotype within T3 Bos taurus main lineage. Thus, we hypothesized that the Jeju and Yunbian cattle may represent one of the original native North East Asian cattle in the region.     

Identification of resistance-associated proteins in closely-related maize lines varying in aflatoxin accumulation

Aspergillus flavus infection of maize and subsequent contamination with carcinogenic aflatoxins poses serious health concerns, especially in developing countries. Maize lines resistant to A. flavus infection have been identified; however, the development of commercially-useful aflatoxin-resistant maize lines has been hindered due to a lack of breeding markers. To identify maize resistance-associated proteins (RAPs) as potential markers for breeding, 52 BC1S4 lines developed from crosses between five African maize inbreds and five temperate aflatoxin-resistant lines were screened using the kernel screening assay. Five pairs of closely-related lines that had 75?C94% genetic similarity within each pair and which varied within each pair in aflatoxin accumulation were selected for proteomic investigation. Kernel embryo and endosperm protein profile differences within the pair and across pairs were compared using two-dimensional polyacrylamide gel electrophoresis. Differentially expressed (??1.5-fold) RAPs were sequenced through tandem mass spectrometry and were identified as antifungal, stress-related, storage or regulatory proteins. Sequence homology analysis highlighted several proteins in maize that confer resistance to A. flavus infection and/or aflatoxin production.     

Larval Exposure to Parasitic Varroa destructor Mites Triggers Specific Immune Responses in Different Honey Bee Castes and Species

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Aquatic nematodes from Ethiopia VII

Three species of Rhabdolaimus de Man, 1880 and two (of which one is new to science) of Udonchus Cobb, 1913 are described from sediment samples of two lakes, two rivers and a hot spring, Ethiopia. Udonchus merhatibebi n.sp. is characterized by a distinctly truncate lip region and small cardia surrounded by gland cells that he on the anterior intestine at 45 °. The presence of twelve rugae in the cheilostome in the genus Udonchus is reported here for the first time. As a result, the family Rhabdolaimidae has been moved from suborder Leptolaimina to the superfamily Microlaimoidea in the suborder Chromadorina. The family Rhabdolaimidae is also subdivided into the subfamilies Rhabdolaiminae Chitwood, 1951 and Undonchinae n. subfam.. Scanning electronmicroscopic pictures of the five species viz. R. aquaticus de Man, 1880, R. cf. minor Cobb, 1914, R. terrestris de Man, 1880, U. merhatibebi n.sp. and U. tenuicaudatus Cobb, 1913 are also given.Abbreviations ABE = anterior body end - ABW = anal body width - Amph = amphid - Amph W = amphidial fovea width - CBW = corresponding body width - GL = gonad length - G1L = anterior gonad length - G2L = posterior gonad length - L = length - LM = light microscope - LRW = lip region width - MBW = maximum body width - n = number of specimens - NR = nerve ring from the anterior end - Ph L = pharyngeal length (neck length) - RL = rectal length - SEM = scanning electron microscope - V-A = distance from vulva to anus - W = width     

Insulin-like growth factor binding protein-4 differentially inhibits growth factor-induced angiogenesis

An in-depth understanding of the molecular and cellular complexity of angiogenesis continues to advance as new stimulators and inhibitors of blood vessel formation are uncovered. Gaining a more complete understanding of the response of blood vessels to both stimulatory and inhibitory molecules will likely contribute to more effective strategies to control pathological angiogenesis. Here, we provide evidence that endothelial cell interactions with structurally altered collagen type IV may suppress the expression of insulin-like growth factor binding protein-4 (IGFBP-4), a well documented inhibitor of the IGF-1/IGF-1R signaling axis. We report for the first time that IGFBP-4 differentially inhibits angiogenesis induced by distinct growth factor signaling pathways as IGFBP-4 inhibited FGF-2- and IGF-1-stimulated angiogenesis but failed to inhibit VEGF-induced angiogenesis. The resistance of VEGF-stimulated angiogenesis to IGFBP-4 inhibition appears to depend on sustained activation of p38 MAPK as blocking its activity restored the anti-angiogenic effects of IGFBP-4 on VEGF-induced blood vessel growth in vivo. These novel findings provide new insight into how blood vessels respond to endogenous inhibitors during angiogenesis stimulated by distinct growth factor signaling pathways.     

Leishmania aethiopica: strain identification and characterization of superoxide dismutase-B genes

This study was performed to characterize the genes that code for superoxide dismutase (SOD) in Leishmania aethiopica. It involved three main steps: specimen collection and parasite isolation, species identification, and molecular characterization of the SOD genes. Out of 20 skin slit specimens cultured and processed from suspected cutaneous leishmaniasis patients enrolled in the study, five (25%) were found to be positive for motile promastigotes. Isoenzyme electrophoresis and PCR-RFLP results confirmed that the isolates were L. aethiopica. Superoxide dismutase-B (SODB) genes were identified from L. aethiopica for the first time. Iron superoxide dismutase-B genes amplified from promastigotes of L. aethiopica (LaeFeSODB) were similar in size to the SODB genes of other Leishmania species. Nucleotide sequences of LaeFeSODB1 showed 95.4, 93.5, and 97.3% identity with L. donovani SODB1 (LdFeSODB1) L. major SODB1 (LmFeSODB1) and L. tropica SODB1 (LtrFeSODB1), respectively. Similarly, LaeFeSODB2 showed 95.9 and 94.1 and 97.6% identity with LdFeSODB2 and LmFeSODB2 and LtrFeSODB2, respectively. On the other hand, predicted amino acid sequence comparison indicated that LaeFeSODB1 had 91.3, 89.8, and 93.9% identity with LdFeSODB1, LmFeSODB1, and LtrFeSODB1, respectively. The difference in nucleic acid sequence of LaeFeSODB from that of LmFeSODB and LtrFeSODB can be utilized to develop specific molecular methods that help differentiate these species in places where there is an overlap in the distribution of these species. In addition, the data provide information about the situation of L. aethiopica with respect to SODB genes.     

A USA–Africa collaborative strategy for identifying, characterizing, and developing maize germplasm with resistance to aflatoxin contamination

Aflatoxin contamination of maize by Aspergillus flavus poses serious potential economic losses in the US and health hazards to humans, particularly in West Africa. The Southern Regional Research Center of the United States Department of Agriculture, Agricultural Research Service (USDA-ARS-SRRC) and the International Institute of Tropical Agriculture (IITA) initiated a collaborative breeding project to develop maize germplasm with resistance to aflatoxin accumulation. Resistant genotypes from the US and selected inbred lines from IITA were used to generate backcrosses with 75% US germplasm and F₁ crosses with 50% IITA and 50% US germplasm. A total of 65 S₄ lines were developed from the backcross populations and 144 S₄ lines were derived from the F₁ crosses. These lines were separated into groups and screened in SRRC laboratory using a kernel-screening assay. Significant differences in aflatoxin production were detected among the lines within each group. Several promising S₄ lines with aflatoxin values significantly lower than their respective US resistant recurrent parent or their elite tropical inbred parent were selected for resistance-confirmation tests. We found pairs of S₄ lines with 75–94% common genetic backgrounds differing significantly in aflatoxin accumulation. These pairs of lines are currently being used for proteome analysis to identify resistance-associated proteins and the corresponding genes underlying resistance to aflatoxin accumulation. Following confirmation tests in the laboratory, lines with consistently low aflatoxin levels will be inoculated with A. flavus in the field in Nigeria to identify lines resistant to strains specific to both US and West Africa. Maize inbred lines with desirable agronomic traits and low levels of aflatoxin in the field would be released as sources of genes for resistance to aflatoxin production.     

Predicting Odor Pleasantness with an Electronic Nose

A primary goal for artificial nose (eNose) technology is to report perceptual qualities of novel odors. Currently, however, eNoses primarily detect and discriminate between odorants they previously “learned”. We tuned an eNose to human odor pleasantness estimates. We then used the eNose to predict the pleasantness of novel odorants, and tested these predictions in naïve subjects who had not participated in the tuning procedure. We found that our apparatus generated odorant pleasantness ratings with above 80% similarity to average human ratings, and with above 90% accuracy at discriminating between categorically pleasant or unpleasant odorants. Similar results were obtained in two cultures, native Israeli and native Ethiopian, without retuning of the apparatus. These findings suggest that unlike in vision and audition, in olfaction there is a systematic predictable link between stimulus structure and stimulus pleasantness. This goes in contrast to the popular notion that odorant pleasantness is completely subjective, and may provide a new method for odor screening and environmental monitoring, as well as a critical building block for digital transmission of smell.