Genetic diversity and population structure of Urochloa grass accessions from Tanzania using simple sequence repeat (SSR) markers.

Urochloa (syn.-Brachiaria s.s.) is one of the most important tropical forages that transformed livestock industries in Australia and South America. Farmers in Africa are increasingly interested in growing Urochloa to support the burgeoning livestock business, but the lack of cultivars adapted to African environments has been a major challenge. Therefore, this study examines genetic diversity of Tanzanian Urochloa accessions to provide essential information for establishing a Urochloa breeding program in Africa. A total of 36 historical Urochloa accessions initially collected from Tanzania in 1985 were analyzed for genetic variation using 24 SSR markers along with six South American commercial cultivars. These markers detected 407 alleles in the 36 Tanzania accessions and 6 commercial cultivars. Markers were highly informative with an average polymorphic information content of 0.79. The analysis of molecular variance revealed high genetic variation within individual accessions in a species (92%), fixation index of 0.05 and gene flow estimate of 4.77 showed a low genetic differentiation and a high level of gene flow among populations. An unweighted neighbor-joining tree grouped the 36 accessions and six commercial cultivars into three main clusters. The clustering of test accessions did not follow geographical origin. Similarly, population structure analysis grouped the 42 tested genotypes into three major gene pools. The results showed the Urochloa brizantha (A. Rich.) Stapf population has the highest genetic diversity (I = 0.94) with high utility in the Urochloa breeding and conservation program. As the Urochloa accessions analyzed in this study represented only 3 of 31 regions of Tanzania, further collection and characterization of materials from wider geographical areas are necessary to comprehend the whole Urochloa diversity in Tanzania.

Symptoms Analysis of Obsessive-Compulsive Disorder in Adolescents and Adults in a Teaching Hospital.

INTRODUCTION: Obsessive-compulsive disorder has a broadly diverse clinical expression that reflects heterogeneity. Several studies have identified consistent symptom dimensions of obsessive-compulsive disorder. The purpose of this study was to conduct an exploratory symptoms analysis of obsessive-compulsive symptoms in adolescents and adults with obsessive-compulsive disorder. METHODS: This was a cross-sectional study conducted in the Department of Psychiatry, National Medical College. This study examined lifetime occurrence of obsessive-compulsive symptoms included in the 13 symptom categories of the Yale-Brown Obsessive Compulsive Scale. Symptoms analysis was performed on 60 patients with obsessive-compulsive disorder. Eight categories of obsessions and six categories of compulsions from Yale-Brown Obsessive Compulsive Scale were included in the analyses. SPSS software package (version 16) was used to analyze the data and shown in the table. RESULTS: Of 60 adolescents and adults, female and male were in the ratio of 1.2:1. Contamination was the most common occurring obsession followed by aggressive obsession. The most common occurring compulsion was checking followed by washing. Only a minority of patients (13.33%) presented predominantly with obsessions however 18.33% patients presented predominantly with compulsions. Certain obsessions and compulsions co-occur to form a cluster. CONCLUSIONS: In adolescents and adults, obsessive-compulsive disorder is a multidimensional disorder. Symptom dimensions are predominantly congruent with those described in similar studies of adults with obsessive-compulsive disorder.

Phytophthora hedraiandra Detected from Irrigation Water at a Perennial Ornamental Plant Nursery in Virginia.

Water survey for Phytophthora spp. by baiting with rhododendron leaves in April 2006 at a perennial ornamental plant nursery in Virginia detected five isolates showing a unique, previously unknown single-strand conformation polymorphism (SSCP) fingerprint (1). These cultures were isolated from two reservoirs at different depths of water column from surface to 2 m. They were homothallic and produced smooth-surfaced spherical oogonia with an average diameter of 27 µm on 10% V8 agar. Oospores were aplerotic. The paragynous antheridia were averaging 12 µm in diameter. Sporangia were papillate, spherical to ovoid, averaging 39 by 28 µm (length by width). They were caducous with short (<4 µm) pedicels. Chlamydospores and hyphal swellings were not observed. Two isolates were sequenced for rDNA internal transcribed spacer (ITS) 1 and 2 regions and cytochrome oxidase subunit 1 (Cox 1) gene. ITS sequences of both isolates (GenBank Accession Nos. JN376065 and JN376066) were identical to that of Phytophthora hedraiandra type culture (GenBank Accession No. AY707987). Also, the Cox 1 sequence of an isolate (Accession No. JN376067) had 99% homology with that of the type culture (GenBank Accession No. AY69115). Pathogenicity of both isolates was tested on Rhododendron catawbiense and Viburnum tinus, two known hosts of P. hedraiandra (2). For each isolate and host, five leaves and stems on potted plants were wounded by needles and then inoculated by placing over each wound a 5-mm2 mycelial plug from a 7-day-old culture and securing with Parafilm. V8 agar was used instead of mycelial plugs on control plants. After inoculation, each plant was enclosed in a plastic bag for 1 day and then incubated at 22°C with a 12-h photoperiod. Distilled water was sprayed daily for 5 days postinoculation (dpi) until disease symptoms were observed. At 15 dpi, 3 of the 10 inoculated rhododendron leaves and 6 of the 10 stems showed leaf lesions, wilting, dieback, and cankers, eventually leading to rhododendron death. Two of the 10 viburnum leaves and 4 of the 10 stems showed similar symptoms. Leaf lesions were approximately 3 to 5 cm in diameter. P. hedraiandra was recovered from diseased tissues and all resulting cultures showed an identical SSCP fingerprint to tested isolates as well as a P. hedraiandra isolate from Minnesota (3). No symptom developed on control plants. To our knowledge, this is the first report of P. hedraiandra in Virginia. Considering neither host plant has been grown or bought for resale by this nursery, this study indicates that P. hedraiandra may have a wider host range than is currently known. This possibility and the importance of water dispersal for P. hedraiandra in disease epidemiology warrant further investigation. References: (1) P. Kong et al. Fungal Genet. Biol. 39:238, 2003. (2) W. A. Man in't Veld et al. Eur. J. Plant Pathol. 117:25, 2007. (3) B. W. Schwingle et al. Plant Dis. 90:109, 2006.

Effect of maternal alcohol consumption on cerebellum of rat pups: a histological study.

Consumption of alcohol during pregnancy results in fetal alcohol syndrome (FAS) in newborn affecting the central nervous system which is more sensitive to deleterious effect of alcohol. This study was conducted to observe the histological alterations in cerebellum of rat pups born to alcohol consuming mother rats. Virgin female albino rats were given 20.0% (v/v) alcohol through oral route two weeks prior to mating and continued till the weaning of their offspring. On postnatal day 27 (PND27), rat pups were sacrificed. Their brains were collected and weighed. The cerebellums were isolated and processed for histological study. The diameter of Purkinje cell and width of molecular and granular layers of the cerebellar hemisphere were measured. Results showed significantly decreased brain weight in rat pups of experimental group when compared to control. The diameter of Purkinje cells, width of molecular and granular layers were also found to be decreased in the experimental group. These results suggest that the maternal consumption of alcohol affects the brain growth and induces significant alterations in the histological architecture of cerebellum of growing rats.

Effect of prenatal exposure of alcohol in the morphology of developing rat embryo.

The objective this study was to observe the morphological changes in developing rat embryo exposed to alcohol in utero. Virgin female Wistar rats in experimental group (n=15) were given 20% (v/v) alcohol two weeks before mating and throughout the gestational period through oral route. The controls (n=15) were also maintained and were given the tap water. On gestational day 15 (GD15) and 19 (GD19), five rats from each group were sacrificed by cervical dislocation and the abdomen was incised to expose the uterine horn. The number of implantation sites and resorptions were counted and recorded. The body weight and length of the fetuses were also recorded. The litter size and body weight of the newborn were also recorded at the time of birth from the remaining dam. The incidence of resorption was higher in alcohol treated group than in control which was found to be 25% and 8.7% at days 15 and 19 respectively. The body weight and length of fetuses were found to be decreased and was significant at GD15 (p<0.001 for weight and p<0.05 for length). Similarly, the litter size and body weight of newborn were also found to be decreased significantly (p<0.05 for litter size and p<0.01 for body weight). The present study shows that the maternal consumption of alcohol during pregnancy has adverse effect on fetal viability and development of growing embryo.

Utility of phenotypic dermal indices in the detection of Down syndrome patients.

Down syndrome (DS) is the most common cause of mental retardation. The frequency of DS patients is about 1:800 and is mainly because of the presence of extra copy of chromosome number 21. Dermatoglyphic has been well established as a diagnostic aid in number of diseases having hereditary basis. Dermatoglyphic data was obtained by the use of ink and prints on a paper, from 15 cytogenetically confirmed patients of Down syndrome attending to the genetic clinic at BPKIHS. The data were correlated and compared with equal number of controls. Dermatoglyphic prints were used to evaluate the variation in the fingerprint patterns, the presence of simian crease and the difference in 'atd' 'dat' and 'adt' angles between the control and the DS patients. The results showed that both the 'atd' and 'adt' angles differed significantly from the control group. The dactylography study revealed higher incidence of loops and lower incidence of whorls in the DS patients as compared with the controls. This method is non-invasive and cost effective. The observed changes in the 'atd' and 'adt' angles plus the fingerprint patterns in the dermatoglyphic study proved that this simple technique could be a valuable tool for selecting patients of DS for cytogenetics analysis.

Variations in the Phytophthora infestans Population in Nepal as Revealed by Nuclear and Mitochondrial DNA Polymorphisms.

ABSTRACT Phytophthora infestans isolates collected from potato and tomato crops from various parts of Nepal during the 1999 and 2000 crop seasons were characterized for nuclear and mitochondrial DNA polymorphisms using restriction fragment length polymorphism markers. The nuclear DNA probe RG57 detected 11 multilocus genotypes among 280 isolates. Three genotypes were detected 21 times or more, constituting 94% of the total population, whereas frequencies of other genotypes ranged from 0.004 to 0.014. The overall genotypic diversity as estimated by the Gleason index was 1.78. Most of the overall diversity was present at the highest level (i.e., interregional, 46%), indicating limited gene flow among regions. Cluster analysis of multilocus genotypes derived from RG57 and mating type data for Nepalese isolates and representative isolates worldwide showed Nepalese isolates grouping into four clusters. Characterization of 67 isolates for mitochondrial DNA polymorphisms revealed the presence of two mt-haplotypes, Ia and Ib with the proportions of 0.88 and 0.12, respectively. Polymorphisms in nuclear and mitochondrial DNA revealed a moderate level of diversity in this population. Genotype NP3 had an identical RG57 fingerprint to US1 and had mt-haplotype Ib, confirming the presence of an old population in Nepal. Most of the genotypes had a different RG57 fingerprint than that of US1 and mt-haplotype Ia, the common characteristics of new populations. The presence of a new population at high proportions in Nepal was consistent with the global trend of mt-haplotype distribution, and suggests the displacement of old populations. This study indicates at least three possible introductions of P. infestans to Nepal.