PCR screening reveals abundance of bovicin-like bacteriocins among ruminal Streptococcus spp. isolated from beef and dairy cattle

AIMS

To investigate the inhibitory activity and the distribution of biosynthetic genes encoding bovicin-like bacteriocins among ruminal Streptococcus isolated from beef and dairy cattle.

METHODS AND RESULTS

Most isolates were classified as Streptococcus equinus and Streptococcus lutetiensis based on 16S rRNA sequencing. The antimicrobial activity of 150 ruminal streptococci isolated from beef and dairy cattle were tested by deferred inhibition assays and their genetic diversity was characterized by BOX-PCR. The frequency of biosynthetic genes associated with the biosynthesis of bovicin-like bacteriocins (bovicin HC5 and bovicin 255) was investigated by PCR screening. Approximately 33% of the ruminal streptococci isolated from Nellore heifers showed inhibitory activity in vitro with the majority harbouring genes for bacteriocin biosynthesis. In contrast, streptococci from Holstein cows showed limited inhibitory activity and a lower frequency of bacteriocin biosynthetic genes.

CONCLUSIONS

Streptococcus from the rumen of beef and dairy cattle exhibit remarkable differences in inhibitory activity and distribution of genes associated with the biosynthesis of prototypical bovicins (bovicin HC5 and bovicin 255).

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings demonstrate that bovicin HC5 is distributed among ruminal streptococci from different breeds of cattle. The high degree of conservation of the bovicin HC5 structural gene among strains of ruminal streptococci suggests that random genetic drift is not a dominant force in the evolution of this bacteriocin.

Calcium and magnesium ion removal from water feeding a steam generator by chemical precipitation and flotation with micro and nanobubbles

This work summarises the results of calcium and magnesium ion removal from raw water feeding an industrial steam generation system. The cations were precipitated with sodium phosphate before separation of the solids by dissolved air flotation, with micro and nanobubbles. Studies were done at bench scale and validated at pilot scale (raw water feed = 1 m³h^-1; air-to-solids ratio = 0.046 mg of air mg^-1 of solids; residence time = 11 min). Results indicated that chemical precipitation followed by flotation significantly improved the quality of the boiler water. Best results were obtained after precipitating the cations with 50 mg L^-1 of sodium phosphate at pH 11.5 and flotation with a saturation pressure (P _sat) of 4 bar, a recycling ratio of 30% and a sodium oleate concentration of 20 mg L^-1 as an hydrophobizing reagent. The latter assisted the adhesion of the nanobubbles (100-500 nm) generated at 4 bar with a numeric concentration of about 2.5 × 10⁸NBs mL^-1. At pilot scale, the total hardness in the solution decreased by 80%; the residual calcium and phosphate ion concentrations were 12 and 2 mg L^-1 respectively. This cell was designed including lamellae and perforate plate to improve the superficial loading capacity (up to 9 m h^-1). The results were explained by chemical and interfacial phenomena and it is believed that this technique has great potential in water softening processes.

Separation of emulsified crude oil in saline water by flotation with micro- and nanobubbles generated by a multiphase pump

The flocculation-column flotation with hydraulic loading (HL, >10 m h^-1) was studied for the treatment of oil-in-water emulsions containing 70-400 mg L^-1 (turbidity = 70-226 NTU) of oil and salinity (30 and 100 g L^-1). A polyacrylamide (Dismulgan, 20 mg L^-1) flocculated the oil droplets, using two floc generator reactors, with rapid and slow mixing stages (head loss = 0.9 to 3.5 bar). Flotation was conducted in two cells (1.5 and 2.5 m) with microbubbles (MBs, 5-80 μm) and nanobubbles (NBs, 50-300 nm diameter, concentration of 10⁸ NBs mL^-1). Bubbles were formed using a centrifugal multiphase pump, with optimized parameters and a needle valve. The results showed higher efficiency with the taller column reducing the residual oil content to 4 mg L^-1 and turbidity to 7 NTU. At high HL (27.5 m h^-1), the residual oil concentrations were below the standard emission (29 mg L^-1), reaching 18 mg L^-1. The best results were obtained with high concentration of NBs (apart from the bigger bubbles). Mechanisms involved appear to be attachment and entrapment of the NBs onto and inside the flocs. Thus, the aggregates were readily captured, by bigger bubbles (mostly MBs) aiding shear withstanding. Advantages are the small footprint of the cells, low residence time and high processing rate.

Brain MRI in mucopolysaccharidosis: effect of aging and correlation with biochemical findings

OBJECTIVE

To investigate the influence of aging on conventional MRI and magnetic resonance spectroscopy (MRS) findings of mucopolysaccharidosis (MPS) patients and to test the correlation of enzyme levels, urinary glycosaminoglycans (GAG), and neuroimaging findings.

METHODS

Sixty patients with MPS types I (n = 8), II (n = 31), IV-A (n = 4), and VI (n = 17) underwent T2, fluid-attenuated inversion recovery (FLAIR), and MRS of the brain. For analysis of MRI variables, we measured the normalized cerebral volume (NCV), CSF volume (NCSFV), ventricular volume (NVV), and lesion load (NLL) on FLAIR using semiautomated and automated segmentation techniques. For MRS, a point-resolved spectroscopy technique was used. Voxels were positioned at the white and gray matter. Statistical analysis involved Pearson or Spearman tests for correlation between neuroimaging, age, enzyme levels, and urinary GAG.

RESULTS

The median age at onset of the disease was 20 months. Patients with longer disease duration had more NLL in the white matter (r = 0.28, p = 0.03), and this difference was more pronounced in MPS II patients (r = 0.44, p = 0.02). Metabolites ratios in MRS, NCV, NCSFV, and NVV did not correlate with disease duration or age of the patients (p > 0.05). MRI and MRS variables in either the white or the gray matter did not correlate with enzymatic activity or GAG levels. Patients with MPS II had a lower mean NCV (p < 0.001).

CONCLUSIONS

Our data showed that white matter lesion is more extensive as disease duration increases, especially in mucopolysaccharidosis type II patients. MRI and magnetic resonance spectroscopy findings did not correlate with either enzymatic or glycosaminoglycan levels.

In vitro activities of new and conventional antimycotics against fluconazole-susceptible and non-susceptible Brazilian Candida spp. isolates

The substantial increase in the rate of azole resistant Candida spp. yeast infections has become a serious treatment problem requiring new and more active antifungal agents. In this study, the in vitro activities of ravuconazole and albaconazole were compared with those of amphotericin B, flucytosine, itraconazole and fluconazole against 162 Brazilian isolates of Candida spp. from which 48 isolates had previously shown lower susceptibility or resistance to fluconazole. Ravuconazole susceptibility ranged from 84.6% (Candida albicans) to 100% for other species and albaconazole MIC(90) was < or =1.0 microg ml(-1) for all the species emphasising the potent activity of these triazoles. To our knowledge this is the first study evaluating the susceptibility of C. dubliniensis to albaconazole.

The aortic valve with two leaflets--a study in 2,000 autopsies

Our study is based on the examination of 2,000 aortic valves obtained from fresh cadavers (1,499 males, 501 females) at the Institute of Forensic Medicine in Rio de Janeiro. We discovered 13 valves having two leaflets, giving a prevalence of 0.65%, much lower than generally reported in the literature. All 13 valves were from males, 10 from whites, three from mulattos, and none from blacks. Special attention was given to the raphe and the leaflets, the calcification of which can lead to stenosis. The only valves with normal texture and flexibility were two obtained from children less than one year old. All the other valves were thickened, and five of them had some degree of calcification. Six valves were judged to be functioning normally, while 7 valves were abnormal, 5 being stenotic and two showing evidence of insufficiency. The insufficiency in one was due to endocarditis, but in the other was due to redundancy of the leaflets. The only other cardiac anomaly discovered in these 13 cases was one patient with aortic coarctation. Bifoliate aortic valve, therefore, is probably the most common cardiac anomaly, although its prevalence as discovered in Brazil is lower than that reported in the literature. It affects mainly white males. After the fourth decade of life, most valves present some thickening, with stenosis being the most common complication. As is well recognised, infective endocarditis and aortic insufficiency are the other frequent complications. It is in general, nonetheless, an isolated anomaly.

Genetic polymorphism of morphological and biochemical characters in a Natal, Brazil, population of Lutzomyia longipalpis (Diptera: Psychodidae)

The phlebotomine sand fly, Lutzomyia longipalpis, is the vector of visceral leishmaniasis in the New World. Variability in its tergal spot morphology has led to conflicting interpretations of the species status of the various forms. An L. longipalpis field population from eastern Brazil was found with three co-occurring morphological variations--1-spot, 2-spot, and an intermediate form. Genetic profiles were established for each form. Fifteen isoenzyme loci provided the data matrix for comparison of genetic variation among the forms. Spot patterns and isoenzyme frequencies fit Hardy-Weinberg expectations, and no significant differences in isoenzyme frequencies were associated with morphological phenotype. The spot phenotype appears to be a polymorphic character not related to genetic isolation or differentiation at the species level.

[The provision of health services in Chile: historical aspects, dilemmas and perspectives]

The evolution of the health system in Chile, since its beginning and during the National Health Service period is described. The transformations that this system underwent from 1980 on, during the military regime, and the changes introduced by the democratic governments from 1990 on, with the purpose of correcting distortions introduced in the previous period, are commented on. The production of the health services is compared as between the public and private sub-sectors. The indicators used are outpatient attendance per thousand insured inhabitants, use of, lab texts on the same populational basis, hospitalization rates, discharges per thousand insured and surgery rates per thousand. Differences between the two sub-systems are commented on as also are those related to user satisfaction in the two sub-systems. The chief challenges to the public system are considered as well as their possible responses to them on the basis of current policies and the solutions implemented. The present situation in the Public/Private mix in health care in Chile gives rise to the positive expectation that the public subsystem may succeed in maintaining its historical leadership in the orientation and health services offered in this country. This positive view is supported by the rigorous geographic and demographic logic of the public subsystem, the stable availability of financial resources (result of the 7% contribution for health applied on all salaries, complemented by tax funds), a not completely modern but reliable network of public health facilities and the considerable motivation shown by its staff. Some features of the Chilean health system's development are mentioned as potentially useful to the development of health systems in other countries, especially in Latin America, such as organization and management of regional health services, innovative methodologies in health service payment (diagnosed related payment, management agreements and per capita financing for primary care); the health surveilance system (especially for food and drugs) and the state regulation of private health care financers.

The sand fly fauna (Diptera: Psychodidae: Phlebotominae) of a focus of cutaneous leishmaniasis in Ilhéus, State of Bahia, Brazil

The municipality of Ilhéus, State of Bahia, has a focus of cutaneous leishmaniasis where entomological studies were carried out to determine the sand fly species and their habits. Lutzomyia migonei, L. sallesi, L. tupynambai, L. schreiberi, L. intermedia, L. whitmani, L. yuilli yuilli, L. fischeri, L. pessoai, L. shannoni and L. misionensis were identified. Lutzomyia whitmani was the predominant species. Specimens were collected indoors, at peridomestic sites, in the cocoa plantations and in other types of collections. Females fed readily on humans and were attracted to domestic animals. Our evidence suggests that L. whitmani is a probable vector.

Variation between geographical populations of Lutzomyia (Nyssomyia) whitmani (Antunes & Coutinho, 1939) sensu lato (Diptera:Psychodidae:Phlebotominae) in Brazil

Phylogenetic analysis of morphometric and biological characters indicated that there are two distinct forms of Lutzomyia whitmani in Brazil: one is present both north and south of the River Amazonas in the State of Pará while the other occurs in northeast Brazil, in the State of Ceará, and further south, including the type locality in State of Bahia. The Amazonian form is reportedly neither strongly anthropophilic nor synanthropic, and it is the vector of Leishmania shawi; whereas the southern form is often collected peridomestically, while biting man, and has been found infected with Le.(V.) braziliensis. The ratio of the length of the genital filaments to that the genital pump was found to be consistently smaller in males of the Amazonian populations. A middle repetitive DNA element was isolated by differentially screening a genomic library made using Amazonian material, and the sequence was diagnostic for this form of Lu. whitmani (being absent or occurring in low copy number in the southern form). The total evidence suggests there are at least two, geographically-isolated forms of Lu. whitmani, which may represent different cryptic species.

[An expert clinical diagnosis system for the support of the primary consultation]

In Brazil, as in other Latin American countries, there was a sharp increase in the number of medical schools in the past 20 years. The result was a steep increase in the number of physicians. These professionals are in many cases, however, poorly trained. As a consequence, public, as well as private health services, are exposed to professionals of great diversity of qualification. Few effective solutions have been proposed for this health services management problem. This paper presents a potential solution. It exposes preliminary results of field tests of an Expert System based on the first author's (Rozenbojm) three decades of experiences as a clinician, and medical residency advisor. The system was developed using ESE IBM Expert Systems language and a mainframe hardware. It was designed to support diagnosis based only in anamnesis and physical examination data, without lab or X ray support. Its original purpose was to increase the primary care physician's diagnostic and therapeutic accuracy. An initial test with specialist panels (endocrinology, cardiology, nephrology, G.O., gastroenterology, pediatrics and pneumology) revealed spell out a diagnostic and therapeutic concordance rate over 95 percent (based on real everyday practice cases brought by the specialists). A second test was performed in a private Health Care Network, at primary care level. In this case, concordance rate was over 83 percent in diagnostic aspects and 95 percent in the clinical orientation aspects. This expert system may be very useful for Health Services providing, first encounter standardization, medical graduate basic education and cost containment. The next proposed steps includes transcription of the software for personal computer utilization and an evaluation of its economic impacts.

[Work situation of physicians graduating from medical residency programs in the State of São Paulo, Brazil]

The authors report on a study conducted to analyze the professional situation of physicians residing in the State of São Paulo, Brazil, five years after completion of a medical residency program. At least 50% of the professionals were interviewed in each specialty. A heavy work load was observed in physicians working both in the metropolitan area of the State capital and in other regions of the State. Male doctors had a higher income than female ones. The latter, however, had a higher proportion working in a single specialty, although 16.8% did not practice in the specialty in which they were trained. The most frequent working environment was a hospital, followed by an ambulatory facility and a private office. The metropolitan area physicians exceeded the remaining in teaching activities and public hospital appointments. They had also a higher tendency to work in a different specialty. This study offers significant information with respect to professional decisions as well as regarding the creation or expansion of residency programs.

A study of sandfly species (Diptera: Psychodidae: Phlebotominae) in a focus of cutaneous leishmaniasis in the municipality of Baturité, Ceará, Brazil

In a study on putative vectors of cutaneous leishmaniasis in Baturité, Ceará State, Brazil, six sandfly species were identified: Lutzomyia longipalpis, L. wellcomei, L. peresi, L. whitmani, L. shannoni and L. migonei. In general L. whitmani and L. migonei were the predominant species. They were collected in periodomiciliary areas and were attracted by man and equines. L. whitmani was the most anthropophilic species. Studies using animals as bait showed that blood-feeding occurs throughout the night. Previously L. whitmani had been found infected with a Leishmania species of the braziliensis complex and L. migonei was infected with peripylarian flagellates. In combination these findings suggest that they may be responsible for periodomestic transmission of cutaneous leishmaniasis.

Studies on sandfly fauna (Diptera: Psychodidae) in a foci of cutaneous leishmaniasis in mesquita, Rio de Janeiro State, Brazil

In a study on vectors of cutaneous leishmaniasis in Mesquita, Rio de Janeiro State, Brazil, eleven species of sandflies were found: Lutzomyia longipalpis, L. fischeri, L. quinquefer, L. intermedia, L. whitmani, L. shannoni, L. cortelezzii, L. edwardsi, L. migonei, L. lanei and L. firmatoi. Lutzomyia intermedia was the predominant species. It was collected indoors but in much higher numbers outdoors, in the close vicinity of houses. In comparative captures it was found to feed more frequently on equines, and less frequently on man and dogs. Studies, using man and animals as baits, showed that blood-feeding started in the evening, and remained stable during the night, until early morning. June, August and October were the months of highest density.

[Phlebotomus of Vargem Grande, a focus of cutaneous leishmaniasis in the State of Rio de Janeiro]

In Vargem Grande, an endemic area of cutaneous leishmaniasis in State of Rio de Janeiro, where Lutzomyia intermedia had been found infected with Leishmania braziliensis, we performed a series of captures of sandflies to increase the knowledge on their behaviour. The following species were found among 8,671 sandflies collected: L. intermedia, L. migonei, L. longipalpis, L. lanei, L. fischeri, L. firmatoi, L. monticola, L. schreiberi, L. whitmani, L. pelloni, L. barrettoi e L. (Pi) sp. Inside houses and outdoors close to the houses, on human bait and in light traps, the predominant species was L. intermedia, followed by L. migonei, both being more numerous between 9 and 11 p.m. than from 6 to 8 p.m. In a plantation, L. migonei was predominant. In simultaneous captures on man and dog as baits, L. intermedia was more frequent on the former, L. migonei on the latter.