Use of serology and real time PCR to control an outbreak of bovine brucellosis at a dairy cattle farm in the Nile Delta region,Egypt

Background

Bovine brucellosis remains one of the most prevalent zoonotic infections affecting dairy cattle in developing countries where the applied control programs often fail. We analyzed the epidemiologic pattern of bovine brucellosis in a dairy cattle herd that showed several cases of abortions after regular vaccination with RB51 (B. abortus vaccine). In 2013 thirty dairy cows, from a Holstein-Friesian dairy herd with a population of 600 cattle, aborted five months post vaccination by a regular RB51 vaccine. Blood samples were drawn from milking cows and growing heifers, as well as heifers and cows pregnant up to 6 months. These samples were collected in June 2013 (n?=?257) and May 2014 (n?=?263) and were tested by real time (rt)-PCR as well as serological tests, in particular Rose Bengal Test (RBT), Enzyme-Linked Immunosorbent Assays (ELISA) and Fluorescence Polarization Assay. Tissue specimens were also collected from an aborted fetus and cultured. Isolates were subjected to bacteriological typing tests at the genus and species levels.

Results

Five months post vaccination with RB51 vaccine, Brucella (B.) DNA was detected in blood samples of cows by rt-PCR. The serological tests also revealed the spread of Brucella field strains within the herd in 2013. Four Brucella isolates were recovered from specimens collected from the aborted fetus. These isolates were typed as follows: one B. abortus RB51 vaccine strain and three isolates of B. abortus field strain. The seropositive cows with positive rt-PCR might indicate an infection by the Brucella field strain; while the positive rt-PCR results from seronegative animals may either be due to circulating RB51 vaccine DNA in vaccinated animals or to circulating field strain in infected animals before seroconversion.

Conclusion

The results herein suggest that PCR can be a good supplementary tool in an outbreak situation, if an assay is available that can differentiate vaccine and field strains with a high analytical sensitivity. We recommend using RBT and ELISA in parallel in outbreak situations, to identify as many infected animals as possible during the initial screenings. This test procedure should be repeated for at least three successive negative tests, with one month interval.

     

An Octopus-Derived Peptide with Antidiuretic Activity in Rats

Discovering new drug candidates with high efficacy and few side effects is a major challenge in new drug development. The two evolutionarily related peptides oxytocin (OXT) and arginine vasopressin (AVP) are known to be associated with a variety of physiological and psychological processes via the association of OXT with three types of AVP receptors. Over decades, many synthetic analogs of these peptides have been designed and tested for therapeutic applications; however, only a few studies of their natural analogs have been performed. In this study, we investigated the bioactivity and usefulness of two natural OXT/AVP analogs that originate from the marine invertebrate Octopus vulgaris, named octopressin (OTP) and cephalotocin (CPT). By measuring the intracellular Ca²⁺ or cyclic AMP increase in each OXT/AVP receptor subtype–overexpressing cell, we found that CPT, but not OTP, acts as a selective agonist of human AVP type 1b and 2 receptors. This behavior is reminiscent of desmopressin, the most widely prescribed antidiuretic drug in the world. Similar to the case for desmopressin, a single intravenous tail injection of CPT into Sprague-Dawley rats reduced urine output and increased urinary osmolality. In conclusion, we suggest that CPT has a significant antidiuretic effect and that CPT might be beneficial for treating urological conditions such as nocturia, enuresis, and diabetes insipidus.     

Protective effect of anthocyanins from black soybean seed coats on UVB-induced apoptotic cell death in vitro and in vivo

UVB radiation proves to be one of the most relevant environmental risks because of its hazardous effects, such as premature skin aging and especially skin photocarcinogenesis. Anthocyanins, water-soluble pigments present in plants, are known to be powerful antioxidants that help protect plants from UV damage. In this study, we aimed at investigating the protective effect of anthocyanins from black soybean [Glycine max (L.) Merr] seed coats on UVB-induced apoptosis, and furthermore, we investigated the molecular mechanism responsible for regulation of apoptosis in vitro and in vivo. Pretreatment with anthocyanins reduced UVB-induced reactive oxygen species levels and inhibited UVB-induced apoptotic cell death through the prevention of caspase-3 pathway activation and reduction of proapoptotic Bax protein levels. UVB irradiation induced apoptotic cell death, which was inhibited by topical application of anthocyanins in hairless mice. It is concluded that anthocyanins from the seed coat of black soybeans may be useful compounds to modulate UVB-induced photoaging.     

Expression of nitric oxide synthase isoforms in the testes of pigs

This study examined the expression of three isoforms of nitric oxide synthase (NOS) in the testes of pigs. Immunohistochemical studies demonstrated the presence of nNOS, eNOS and iNOS in interstitial cells, primary spermatocytes and spermatids. Positive immunoreactions for eNOS and iNOS were detected in peritubular myoid cells. Some vascular endothelial cells were positive for nNOS and eNOS. The expression of nitrotyrosine was detected in interstitial cells. In addition, the histochemical study revealed that all the interstitial cells were stained positively for NADPH-diaphorase, although some spermatids and vascular endothelial cells displayed moderate enzymatic activity. These findings suggest that three isoforms of NOS are expressed in the testis of pig and that they play important roles in the biology of interstitial cells that produce testosterone, as well as in spermatogenesis in the seminiferous tubules.     

Historical processes and landscape context influence genetic structure in peripheral populations of the collared lizard (<Emphasis Type="Italic">Crotaphytus collaris</Emphasis>)

Populations at the periphery of a species’ range often show reduced genetic variability within populations and increased genetic divergence among populations compared to those at the core, but the mechanisms that give rise to this core-periphery pattern in genetic structure can be multifaceted. Peripheral population characteristics may be a product of historical processes, such as founder effects or population expansion, or due to the contemporary influence of landscape context on gene flow. We sampled collared lizards (Crotaphytus collaris) at four locations within the northern Flint Hills of Kansas, which is at the northern periphery of their range, to determine the genetic variability and extent of genetic divergence among populations for ten microsatellite loci (n = 229). We found low genetic variability (average allelic richness = 3.37 ± 0.23 SE; average heterozygosity = 0.54 ± 0.05 SE) and moderate population divergence (average F_ST = 0.08 ± 0.01 SE) among our sample sites relative to estimates reported in the literature at the core of the species’ range in Texas. We also identified differences in dispersal rates among sampling locations. Gene flow within the Flint Hills was thus greater than for other peripheral populations of collared lizards, such as the Missouri glade system where most of the mesic grasslands have been converted to forest since the last glacial retreat, which appears to have greatly impeded gene flow among populations. Our findings signify the importance of considering landscape context when evaluating core-peripheral trends in genetic diversity and population structure.     

Prevalence of antimicrobial residues in raw table eggs from farms and retail outlets in Enugu State,Nigeria

The use of antimicrobial agents in poultry production results in their accumulation in the body tissues and products such as milk and egg. The subsequent accumulation of these drugs and their metabolites in body cells is known as drug residue. This study was designed to determine the prevalence of antimicrobial residues in eggs from poultry farms and retail outlets in Enugu State, Nigeria. Eggs from 25 selected commercial farms and ten retail outlets were screened for the prevalence of antimicrobial residue. Also, structured questionnaires were administered to 25 commercial farms in the state to determine the management practices and the most widely used antimicrobial drugs in farms and possible association between the management practices and the occurrence of antimicrobial residues in eggs from these farms. All the 25 farms surveyed use oxytetracycline. Eggs from nine of the surveyed farms tested positive for antimicrobial residue and three of the ten surveyed farms also tested positive for antimicrobial residue. No association was observed (p 0.05; Fisher’s exact test) between the occurrence of antibiotic residues in eggs and farm size, feed source and housing systems. This study was able to demonstrate the presence of antimicrobial residues in eggs destined for human consumption. Drugs like nitrofurans which has been banned for use in food animals are still very much in use in Enugu State, Nigeria. Antibiotics given as feed additives may give rise to drug residues in food animals.     

Cobalt reduces nitrate inhibition of nodulation in mungbean (Vigna radiata)

 A cobalt-mediated decrease in ethylene production reduced the inhibition of nodulation by nitrate in Vigna radiata (mungbean). Nitrate increased the ethylene production in 5-day-old seedlings, while it caused a reduction in the nodulation status (nodule number and nodule weight) and nodule efficiency (acetylene reduction activity) in mungbean plants. The application of cobalt chloride inhibited nitrate-affected ethylene production and also decreased the inhibitory effect of nitrate on nodulation. The effect of cobalt was most marked on nodule number. Received: 6 August 1999     

A putative RNA silencing component protein FoQde-2 is involved in virulence of the tomato wilt fungus <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">lycopersici</Emphasis>

RNA silencing pathways in filamentous fungi are composed of multiple component proteins and known to be involved in vegetative growth, virulence or sexual reproduction. We found that the tomato wilt fungus, Fusarium oxysporum f. sp. lycopersici (Fol), carries four homologues genes of Qde-2, an argonaute protein gene and one of the main component protein genes in Neurospora crassa. Gene targeting revealed that FoQde-2, one of the Qde-2 homologues in Fol, is involved in virulence to tomato but not in vegetative growth.