Fasciation in <Emphasis Type="Italic">Crassula argentea</Emphasis>: molecular identification of phytoplasmas and associated antioxidative capacity

The present study reports on phytoplasma induced fasciation in Crassula argintea (Crassulaceae). DNA was extracted from symptomless and fasciated tissues and amplified by nested PCR using universal primers P1/P7 followed by R16F2n/R16R2 produced amplicons of 1.2 Kb. The nucleotide sequence analyses of the amplicons indicated that fasciated plants were infected by phytoplasma. Phylogenetic analysis placed the Crassula fasciation phytoplasmas in 16SrII-D group. Histochemical staining for reactive oxygen species indicated that phytoplasma infected (PI) tissues possess significantly higher levels of hydrogen peroxide (H₂O₂) rather than superoxide (O₂ ^·-) as compared with symptomless tissues. PI tissues were also associated with a significant increase in antioxidant enzyme activities (catalase, peroxidase, polyphenol oxidase, and glutathione reductase) and electrolyte leakage as compared with symptomless tissues.     

Pathogens of bark beetles (Coleoptera: Curculionidae) in Bulgarian forests

The occurrence and prevalence of bark beetle pathogens in forest stands in Bulgaria were investigated in 944 specimens belonging to 21 bark beetle species. Protozoa, microsporidia, fungi and nematodes occurred in 19 of all investigated species. The infections were found in the gut (nematodes, gregarines, microsporidia), gonads (microsporidia) and hemolymph (nematodes) of the infected insects. Protozoan species (Gregarina typographi, Gregarina spp.) were detected in eight bark beetle species. Morphometric data about G. typographi and Gregarina spp. are presented. The prevalence of the gregarines varied between 1.4% and 64.2%. Microsporidia of the genera Nosema and Chytridiopsis were revealed in three bark beetle species. The prevalence of microsporidia ranged between 1.5% and 11.8%. This is the first report of a microsporidium in Taphrorychus villifrons and of gregarines in T. villifrons, Pityogenes bistridentatus, P. conjunctus, and Orthotomicus erosus. The fungus Beauveria bassiana was found in 3.4% of Hylurgops palliatus specimens. Nematodes (in gut and haemolymph) were revealed in 19 bark beetle species and their prevalence varied between 10% and 98.5%.     

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.

     

Effects of continuous low dose infusion of lipopolysaccharide on inflammatory responses,milk production and milk quality in dairy cows

The objective of this study was to evaluate the effects of continuous low dose infusion of lipopolysaccharide (LPS) on inflammatory responses and milk production and quality in lactating dairy cows. Eight Holstein cows were assigned to two treatments in a cross‐over experimental design. Cows were infused intravenously either with saline solution or with saline solution containing LPS from Escherichia coli O111:B4 at a dose of 0.01 μg LPS/kg body weight for approximately 6 hr each day during a seven‐day trial. The clinical symptoms and milk production performance were observed. Milk samples were analysed for conventional components, fatty acids and amino acids. And jugular vein and mammary vein plasma samples were analysed for concentrations of cytokines and acute phase proteins. LPS infusion decreased feed intake and milk yield. An increase in body temperature was observed after LPS infusion. LPS infusion also increased plasma concentrations of interleukin‐1β, serum amyloid A, LPS‐binding protein, C‐reactive protein and haptoglobin. LPS infusion decreased the contents of some fatty acids, such as C17:1, C18:0, C18:1n9 (trans) and C18:2n6 (trans), and most amino acids except for methionine, threonine, histidine, cysteine, tyrosine and proline in the milk. The results indicated that a continued low dose infusion of LPS can induce an inflammatory response, decrease milk production and reduce milk quality.     

海洋生态资本理论框架下海洋生物资源的存量评估

海洋生态资本是能够直接或间接作用于人类社会经济生产、提供有用的产品流或服务流的海洋生态资源.海洋生态资源包括海洋生物资源及其生境资源.海洋生态资源的存量价值由海洋生物资源存量价值和海洋生境资源存量价值构成.针对我国海洋生物资源的特征,在海洋生态资本理论框架下,提出了鱼类、贝类、甲壳类、头足类、大型海藻等主要海洋生物资源的存量价值评估技术方法,包括物质量评估和价值量评估.探讨了海洋生物资源单位价格确定、评估价值修正、评估方法的适用性、成本扣除等问题.     

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.     

中国潜在产出测算实证研究

在对中国潜在产出测算研究状况进行评介的基础上,分别使用H-P滤波法和生产函数法估算了中国1978—2004年间的潜在产出、产出缺口和潜在产出增长率。结果表明:(1)1978—2004年间,中国的产出缺口出现了波动水平正负交替的周期情形;(2)1995年以前产出缺口的波动幅度比较剧烈且较为频繁,1996年特别是1999年以后产出缺口的变化较为平缓;(3)1997年以后,虽然经济的增长率保持较高的水平,但是生产要素的实际利用水平却逐渐降低;(4)生产函数法得到的结果基本客观的反映了改革开放后,中国开始从计划经济向市场经济过渡到市场经济初步建立这一时期的生产要素使用情况。(5)根据H-P滤波法和生产函数法估算的潜在产出,得到1978—2004年间的平均潜在产出增长率分别为9.54%和9.67%。根据估计结果,在今后几年,通过适当的宏观调控,把中国的经济增长率稳定在8%～9%可能是一个较好的选择。     

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.