Partial Purification and Characterization of Extracellular Protease from Pedicoccus acidilactici

Microbial proteases have wide industrial applications and proteases of the lactic acid bacteria (LAB) have received special attention because of their importance in the food and dairy industry. Of all the LAB, the proteolytic system of the pediococci is the least studied. Therefore, this study was aimed at characterizing and purifying the protease produced by Pediococcus acidilactici grown in de Man, Rogosa and Sharpe (MRS) broth. Casein concentration of 2% (w/v) and 2.5 ml of the crude enzyme were optimal for the activity of the protease. The crude protease had temperature and pH optima of 28 oC and 4.0 respectively thus indicating that the enzyme is a mesophilic and acidic protease. Purification of the enzyme by gel filtration chromatography on Sephadex G75 following ammonium sulphate precipitation gave 2.26 fold increase in purification with specific activity of 46.13 units/mg protein while purification on Sephadex CM50 resulted in reduced purification fold (1.24 - 1.59) with specific activity ranging between 25.39 - 32.54 units/mg protein. The protease showed a characteristic band on SDS-PAGE and the molecular weight was estimated between 45 and 66 kDa. The potential applications of the protease are discussed.Keywords: Protease, lactic acid bacteria, Pediococcus acidilactici, enzyme purification

Epidemiological Factors in Prevalence of Malaria Parasites in Primary Health Facilities Attendees, Ogun State, Nigeria

Malaria caused by Plasmodium species is often observed in areas where malaria is endemic. Malaria prevalence in metropolitan Abeokuta of Ogun State, Nigeria was studied between October, 2012 and January 2013. Oral interviews were used to get personal data of participants. Blood samples were obtained from 384 consented participants from the seven primary health centers. Blood film examination using Giemsa staining techniques was used to detect malaria parasites in the blood. From the 384 participants examined 273 (71.1%) were positive with malaria parasites. Species detected included Plasmodium falciparum (95.6%), Plasmodium malariae (3.3%), P. ovale (0.7%) and P. vivax (0.4%). The age-group 1-11 years had the highest malaria prevalence 94 (81%) while 51-60 had the least 6(54.5%). The malaria prevalence in relation to age was significant (p=0.011, p<0.05). The males 110 (73.8%) were slightly more affected than the females 163 (69.4%), but not statistically significant (p=0.347, p>0.05). Malaria prevalence was significantly higher among those with no formal education 80 (81.6%) and least among post-secondary educational. Prevalence among occupational groups showed significant difference, where the unemployed group were more infected and the retiree group had the least infection (p=0.014, p<0.05). The singles (56.4%) were more infected than the married (43.6%). The prevalence in relation to age was significant (p=0.000, p<0.05). The study has revealed that malaria disease can affect all age groups and both males and females’ sexes irrespective of their educational and occupational cadre. Public enlightenment efforts need to be intensified towards the prevention of malaria

The three-dimensional geometry and merger history of the massive galaxy cluster MACS J0358.8-2955

We present results of a combined X-ray/optical analysis of the dynamics of the massive cluster MACS J0358.8-2955 (z=0.428) based on observations with the Chandra X-ray Observatory, the Hubble Space Telescope, and the Keck-I telescope on Mauna Kea. MACS J0358.8-2955 is found to be one of the most X-ray luminous clusters known at z>0.3, featuring L_X(<r_500) = 4.24*10^45 erg/s, kT = (9.55 +0.58/-0.37) keV, M^{3D}_{gas}(<r_500) = (9.18+/-1.45)*10^13 M_sun, and M^{3D}_{tot}(<r_500) = (1.12+/-0.18)*10^15 M_sun. The system's high velocity dispersion of (1440 +130/-110) km/s (890 km/s when the correct relativistic equation is used), however, is inflated by infall along the line of sight, as the result of a complex merger of at least three sub-clusters. One collision proceeds close to head-on, while the second features a significant impact parameter. The temperature variations in the intra-cluster gas, two tentative cold fronts, the radial velocities measured for cluster galaxies, and the small offsets between collisional and non-collisional cluster components all suggest that both merger events are observed close to core passage and along axes that are greatly inclined with respect to the plane of the sky. A strong-lensing analysis of the system anchored upon three triple-image systems (two of which have spectroscopic redshifts) yields independent constraints on the mass distribution. For a gas fraction of 8.2%, the resulting strong-lensing mass profile is in good agreement with our X-ray estimates, and the details of the mass distribution are fully consistent with our interpretation of the three-dimensional merger history of this complex system.Comment: 17 pages, 17 figures, and 4 tables. Accepted for publication in MNRA

15 colour photometry of Landolt SA95 standard star field

In this paper, we present a set of photometric observations in 15 colors of stars in the Landolt covered by the system range from 300 nm to 1000 nm. Visual magnitudes of the stars being studied in the field are from 10th to 20th mag. The observational methodology and the data reduction procedures are described. The relationships between the BATC intermediate-band system and the Landolt UBVRI broad band system are obtained. A catalogue of the photometry has been produced which contains the SEDs of 3613 stars. The electronic form of this catalogue can be accessed at the CDS via anonymous ftp to cdsarc.u-strasbg.fr.Comment: 21 pages, accepted for publishing by A&

Determinant of Agroforestry Practices among Small Holder Farmers in Oyo State Nigeria

The multiplicity of agroforestry practices demand the choice of appropriate methods that will give the rural farmers an excellent result. Thus, this study analysed the factors determining the choice of agroforestry practices among small holder farmers in Oyo State, Nigeria. Primary data was obtained using multi-stage sampling technique. Structured questionnaire was administered to 250 selected small holder farmers to elicit relevant information and 211 was retrieved and used for this study. The findings revealed that most 55% of the farmers chose agrisilvicutural system while 33.2% and 11.8% of the farmers chose agrosilvopastoral and silvopastoral systems respectively. Most of the farmers were males 89.1%, with average age of 47years indicating they were relatively young with basic formal education. The average farm size of 3.34ha indicated that the study covered small holder farmers. The multinomial logit result showed that factors such as educational level, meeting attendance, type of labour used, household assets significantly determined the choice of agroforestry practices adopted by the farmers. The study therefore recommends the implementation of policies that promote more enlightenment on the benefits of agroforestry to both the educated and non-educated farmers to facilitate quick adoption, provision of incentives to farmers that attend meetings regularly and making available improved agroforestry methods and practices to enhance wider suitability of agroforestry practices

Toxoplasma Gondii Infection in HIV/AIDS: Prevalence and Risk Factors

BACKGROUND: Toxoplasmosis is an infection caused by the protozoan Toxoplasma gondii. It is common in severely immunecompromisedpersons.OBJECTIVE: To determine the seroprevalence of T. gondii infection and the risk factors associated with the infection and to investigate the association between T. gondii infection and CD4 cell count.METHODS: Sera collected from 242 HIV positive HAART- naive patients were tested for T. gondii specific immunoglobulin G antibodies. Information was obtained using a structured questionnaire. Baseline CD4 cell counts were obtained from patients case files. Data was managed using SPSS version 20 software and Microsoft Excel worksheet.RESULTS: One hundred and sixty eight (69.4%) subjects were females while 74(30.6%) were males. One hundred (41.3%) of study participants were Toxoplasma IgG antibody positive. Thirty two(32) HIV positive pregnant women were among this group studied with 12( 37.5%) being Toxo IgG antibody positive. Toxoplasma seropositivity was higher in females (42.8%) than in males (39.2%), P= 0.60. CD4 cell count level of &lt; 200 was negatively associated with Toxoplasma seropositivity than CD4 count . 200 by logistic regression (OR= 0.6; 95% CI 0.3- 1.0). Living in proximity with cat was positively associated with T. gondii infection (P= 0.01).CONCLUSION: T. gondii infection is common in pregnant women indicating greater probability of congenital transmission of T. gondii. This could form a basis for recommending intensifying health education and prophylactic treatment for all HIV positive pregnant women. Measures should be taken to prevent stray cats from entering homes.Keywords: Toxoplasma gondii , IgG, Seroprevalence, HIV positive, CD4 cells

Optical Monitoring of PKS 1510-089: A Binary Black Hole System?

Three deep flux minima were observed with nearly the same time-scales and intervals for the blazar PKS 1510-089 in the past few years. A binary black hole system was proposed to be at the nucleus of this object, and a new minimum was predicted to occur in 2002 March. We monitored this source with a 60/90 cm Schmidt telescope from 2002 February to April. In combination with the data obtained by Xie et al. (2004) in the same period, we presented for the 2002 minimum a nearly symmetric light curve, which would be required by an eclipsing model of a binary black hole system. We also constrained the time-scale of the minimum to be 35 min, which is more consistent with the time-scales ~42 min of the three previous minima than the 89 min time-scale given by the same authors. The wiggling miniarcsecond radio jet observed in this object is taken as a further evidence for the binary black hole system. The `coupling' of the periodicity in light curve and the helicity in radio jet is discussed in the framework of a binary black hole system.Comment: 5 pages, 4 figures, accepted by MNRA

Young stellar clusters and associations in M33

We analyse multi-wavelength observations of 32 young star clusters and associations in M33 with known oxygen abundance (8 < 12 + log(O/H) < 8.7), using ultraviolet (UV), optical, mid-infrared (MIR), CO (1-0) and 21-cm line (HI) observations. We derive their spectral energy distribution, and we determine age, bolometric luminosities, masses and the extinction, by comparing the multi-band integrated photometry to single-age stellar population models. The stellar system ages range between 2 and 15 Myr, masses are between 3 x 10^2 and 4 x 10^4 M_sun, and the intrinsic extinction, A_V, varies from 0.3 to 1 mag. We find a correlation between age and extinction, and between the cluster mass and size. The MIR emission shows the presence of a dust component around the clusters whose fractional luminosity at 24 um, L_{24}/L_{Bol}, decreases with the galactocentric distance. However, the total IR luminosity inferred from L_{24} is smaller than what we derive from the extinction corrections. The Halpha luminosity predicted by population synthesis models is larger than the observed one, especially for low-mass systems (M < 10^4 M_sun). Such a difference is reduced, but not erased, when the incomplete sampling of the initial mass function (IMF) at the high-mass end is taken into account. Our results suggest that a non-negligible fraction of UV ionising and non-ionising radiation is leaking into the ISM outside the HII regions. This would be in agreement with the large UV and Halpha diffuse fractions observed in M33, but it implies that stellar systems younger than 3 Myr retain, on average, only 30% of their Lyman continuum photons. However, the uncertainties on cluster ages and the stochastic fluctuations of the IMF do not allow to accurately quantify this issue. We also consider the possibility that this discrepancy is the consequence of a suppressed or delayed formation of the most massive stars.Comment: 17 pages, 13 figures. Accepted for publications in A&A; v2 --> Table 2 corrected because of a misprint in the FUV magnitude

Galactic structure studies with BATC star counts

We report the first results of star counts carried out with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope in 15 intermediate-band filters from 3000 to 10000 {\AA} in the BATC survey. We analyze a sample of over 1400 main sequence stars ($14\le$V$\le21$), which lie in the field with central coordinates R.A.=$09^h53^m13^s.30$ and DEC=47$^\circ49^{\prime}00^{\prime\prime}.0$ (J2000). The field of view is 0.95 deg$^{2}$, and the spatial scale was 1\arcsec.67. In our model, the distribution of stars perpendicular to the plane of the Galaxy is given by two exponential disks (thin disk plus thick disk) and a de Vaucouleurs halo. Based on star counts, we derive the scale heights of the thin disk to be $320^{+14}_{-15}$ pc and of the thick disk to be $640^{+30}_{-32}$ pc, respectively, with a local density of $7.0\pm1$ of the thin disk. We find that the observed counts support an axial ratio of $c/a\le0.6$ for a de Vaucouleurs $r^{1/4}$ law, implying a more flattened halo. We also derive the stellar luminosity function (SLF) for the thin disk, and it partly agrees with the Hipparcos luminosity function.Comment: 17pages,9 figure

A Substantial Population of Low Mass Stars in Luminous Elliptical Galaxies

The stellar initial mass function (IMF) describes the mass distribution of stars at the time of their formation and is of fundamental importance for many areas of astrophysics. The IMF is reasonably well constrained in the disk of the Milky Way but we have very little direct information on the form of the IMF in other galaxies and at earlier cosmic epochs. Here we investigate the stellar mass function in elliptical galaxies by measuring the strength of the Na I doublet and the Wing-Ford molecular FeH band in their spectra. These lines are strong in stars with masses <0.3 Msun and weak or absent in all other types of stars. We unambiguously detect both signatures, consistent with previous studies that were based on data of lower signal-to-noise ratio. The direct detection of the light of low mass stars implies that they are very abundant in elliptical galaxies, making up >80% of the total number of stars and contributing >60% of the total stellar mass. We infer that the IMF in massive star-forming galaxies in the early Universe produced many more low mass stars than the IMF in the Milky Way disk, and was probably slightly steeper than the Salpeter form in the mass range 0.1 - 1 Msun.Comment: To appear in Natur