The fission yeast FANCM ortholog directs non-crossover recombination during meiosis

The formation of healthy gametes depends on programmed DNA double-strand breaks (DSBs), which are each repaired as a crossover (CO) or non-crossover (NCO) from a homologous template. Although most of these DSBs are repaired without giving COs, little is known about the genetic requirements of NCO-specific recombination. We show that Fml1, the Fanconi anemia complementation group M (FANCM)-ortholog of Schizosaccharomyces pombe, directs the formation of NCOs during meiosis in competition with the Mus81-dependent pro-CO pathway. We also define the Rad51/Dmc1-mediator Swi5-Sfr1 as a major determinant in biasing the recombination process in favor of Mus81, to ensure the appropriate amount of COs to guide meiotic chromosome segregation. The conservation of these proteins from yeast to humans suggests that this interplay may be a general feature of meiotic recombination.     

Ultrastructural analysis of the integument of a desert-adapted mammal, the one-humped camel (Camelus dromedarius)

In this study, we conducted a light microscopic and ultrastructural analysis of the integument of the one-humped camel (Camelus dromedarius). In general, the epidermal strata of the camel integument appeared typical of those found in non-desert mammals. Two cell populations were noted in the stratum basale: one with a flat, non-serrated base and the other with a highly serrated base. Typical fine structure was observed in keratinocytes of the stratum spinosum and stratum granulosum. The stratum corneum was six to 10 cells thick. Within the different strata, overall cell morphologies and the general distribution and relative abundance of cellular organelles appeared typical. Dermal features included the presence of myoepithelial cells surrounding apocrine tubular glands. Inter- or intracellular canaliculi within the secretory cells of the apocrine glands, reported to be present in certain other non-desert mammals, were not evident in the camel. Together, these data indicate that while the camel is clearly adapted for a desert lifestyle, these adaptations do not include significant specializations at the cellular or subcellular level in the integument.     

Ferrous and ferric iron ratio in normal and chlorotic bean plants (Vicia faba L.)

The objective of this study was to determine the ratio and amount of Fe II and Fe III iron in different parts of 20 and 40 day old bean plants grown in pots under normal and HCO-treatment. The Fe II and Fe III iron determination was carried out by a modification of a method described by Vogel (1969). The Fe II and Fe III concentrations in the plant varied according to its age, the plant part, the order of leaves and HCO-treatment. At the second sampling date, the lower total iron content in the lower leaf particularly under the HCO-treatment suggests that the supply of iron from the roots was restricted. The iron content of the different leaves was almost evenly divided into Fe II and Fe III at the first date. At the second date, most of the iron in the bud leaf was present as Fe II. Under HCO-treatment the Fe II content of the bud leaf and the flower was similar as in the corresponding parts of the normal green plants whereas the Fe III content was considerably lowered in these plant parts as result of the HCO-treatment. The results indicate a substantial retranslocation of iron from older to younger leaves and a higher Fe II/Fe III ratio in flowers and bud leaves particularly under HCO-induced chlorosis.     

QTL analysis and regression model for estimating fruit setting in young Citrus trees based on molecular markers

This study was conducted to assess the genetic basis and develop a regression model for a QTL trait, fruit setting of a full sib population of 164 hybrids obtained between ‘Clementine’ mandarin (Citrus reticulata Blanco ‘Clementine) and ‘Orlando’ tangelo’ (Citrus paradisi Macf. ‘Duncan’ × C. reticulata Blanco ‘Dancy’). Fruit setting of a 164 full sib population field-planted in 2007 was evaluated by visual counting of fruits in 2008, 2009, and 2010. We estimated linkage groups and effects of QTLs by using MapQTL5. Based on interval mapping, seven linkage groups of the maternal and eight linkage groups of the paternal maps harboured QTLs of the fruits setting, covering a total 300 of 1744 cM Citrus map. Only three segments were associated with all three-year data (one in ‘Clementine’ and two in ‘Orlando’ map) spanning 60 cM of 1744 cM of Citrus linkage map. Twenty-seven (17%) and 13 (8%) hybrids consistently produced less than 5 fruits and the highest number of fruits (≥50) in their 2nd, 3rd, and 4th ages. Based on BACKWARD elimination procedure of PROC REG option nested in SAS program, regression models constructed for 2008, 2009, and 2010s fruit setting explained 35, 81, and 38% of the total phenotypic variation (R²) observed in the 164 full-sib hybrids, respectively (P ≤ 0.05). This study indicated that early fruit setting was a complex trait affected by many QTLs and the regression model developed in this study might be used to predict performances of hybrids with similar genetic background.     

Molecular epidemiology of Campylobacter isolates from broiler slaughterhouses in Tripoli,North of Lebanon

ABSTRACT

1. The real burden of Campylobacter spp. in Lebanon is still unknown. The aims of this study were to unravel the epidemiology of Campylobacter spp. in broilers at slaughterhouses in Tripoli, North of Lebanon and to characterise their antibiotic resistance profiles.

2. From May to November 2015, sampling was performed through five repeated surveys from 15 slaughterhouses that sold chicken directly to Lebanese customers. Isolates were subjected to pulsed field gel electrophoresis (PFGE) and flaA-restriction fragment length polymorphism (flaA-RFLP).

3. All investigated slaughterhouses were found to be positive for Campylobacter spp. Campylobacter coli was the predominant species (38 isolates) followed by C. jejuni (eight isolates). A noticeable level of resistance was detected among isolates against ciprofloxacin (97% of C. coli and 87.5% of C. jejuni), amoxicillin (89% of C. coli and 75% of C. jejuni), gentamicin (79% of C. coli and 50% of C. jejuni), and co-amoxiclav (24% of C. coli and 25% of C. jejuni). Erythromycin and ertapenem resistance were observed only in C. coli with the following percentages 74% and 13% respectively, but not in C. jejuni. PFGE and flaA-RFLP using DdeI as restriction enzyme divided the strains into 27 and 25 types respectively.

4. The high observed genetic diversity of Campylobacter spp. revealed the complexity of the spread of this genus in broilers. This study highlighted the pressing need to monitor antibiotic resistance and to ensure food safety from ‘farm to fork’ in Lebanon.     

Effects of carbohydrase enzyme supplementation on performance,eggshell quality,and bone parameters of laying hens fed on maize- and wheat-based diets

1. This study was conducted to determine the effects of enzyme supplementation of maize/wheat-based diets on the performance, egg quality, and serum and bone parameters of laying hens.

2. During the 12-week experimental period, a total of 72 laying hens aged 52 weeks were randomly distributed among 6 experimental groups. Each experimental group contained 4 replicates, each with three birds. The experiment was a randomised design consisting of a 3 × 2 factorial arrangement, with three levels of wheat substitution and two levels of enzyme (xylanase: 1500.00 U/kg, β-glucanase: 100 000 U/kg, cellulase: 1 000 000 U/kg, α-amylase: 160 000 U/kg) inclusion in the diet. Wheat replaced 0, 50, or 100% of maize with or without 1.0 g/kg enzyme supplementation in iso-nitrogenous and iso-caloric experimental diets.

3. Body weight, egg production, egg weight, egg mass, eggshell thickness, and the feed conversion ratio were adversely affected by the wheat-based diet. The eggshell quality parameters decreased with enzyme supplementation to the diet.

4. Wheat-based diets adversely affected calcium and phosphorus concentrations in the tibia, but the addition of the enzymes to the wheat-based diet prevented the negative effects of wheat-based diets on tibia mineralisation in laying hens. The wheat-based diets tended to reduce plasma mineral contents, and the addition of enzymes tended to affect plasma minerals and biomechanical properties of the tibia positively in laying hens.

5. These results indicate that wheat-based diets in aged laying hens adversely affected the mineral metabolism compared with maize-based diets, and the negative effects of wheat on bone mineralisation can be prevented by enzyme supplementation to the diets in laying hens.     

A morphometric and stereological study on cervical spinal cord segment of goose

In this study, volume density of white matter and grey matter areas of cervical segment of spinal cord in adult geese weighing 3–4 kg was examined using stereological methods. 10 geese were used as material without sex discrimination. All animals underwent perfusion with 10% buffered formaldehyde. Following the perfusion, animals were kept in 10% formaldehyde for 1 week. Geese were then dissected. Cervical area of spinal cord was revealed removing cervical spine. Tissue samples were obtained from each segment of cervical area. 5 μm thick cross‐sections were taken from these tissue samples via microtome. Series of cross‐sections were obtained by sampling in the ratio of 1/250 including 12 cross‐sections from each cervical segment of every animal. Cross‐sections were stained by haematoxylin eosin. They were photographed under microscope. Volume density (volume fractions) of both whole tissue and white matter and grey matter parts in each cervical segment of spinal cord were calculated using Cavalieri’s Principle. In the study, total volume of cervical segment, volume of white matter and grey matter, and ratios of these volumes one another were assessed in goose.     

Reproduction Efficiency of Eisenia foetida and Substrate Changes During Vermicomposting of Organic Materials

ABSTRACT

Vermicomposting is the processing of organic substrates through digestion by worms, usually Eisenia foetida. The physico-chemical characteristics of the substrates and health of the worms are important parameter for effective vermicomposting. This study assessed reproduction efficiency and reproductive rate of E. foetida and changes in EC, pH, organic C, total Nitrogen and C:N ratio by vermicomposting different substrate mixtures. The study was performed as a completely randomized design with 10 treatments and 4 replicates. Manures from sheep and horse were tested alone and mixed at 50 and 75% with residues of alfalfa and wheat straw. Wheat straw was also tested alone and mixed at 75% with 25% chicken manure. E. foetida were added to the mixtures and allowed to process the substrate mixtures for three months. Final EC, pH, organic C and N levels of vermicompost were measured, as well as the reproductive efficiency and reproductive rate of the E. foetida. All measured characteristics of the finished vermicompost were significantly different depending on substrate. Substrates also changed to differing degrees during vermicomposting. Total C and EC increased in all substrates; and pH, total N, and C:N decreased in all substrates during vermicomposting The greatest change of EC was in the 25% alfalfa + 75% sheep manure mixture, which was 12.8 dS.m-1 initially and 18.6 dS.m-1 in finished vermicompost. Overall, pH declined and EC increased during the preparing of vermicompost.     

胡杨根际可培养细菌的分离及抑制瓜列当种子萌发研究

从胡杨生存的干旱强光照逆境中获得新的细菌资源,从中筛选新的可抑制瓜列当种子萌发的生防菌。采用3种分离培养基,以稀释涂布法对塔里木河流域3处胡杨根系样品进行可培养细菌分离,通过分析分离菌株16S rRNA基因序列确定其种属分类。采用皿内培养法测定其对瓜列当种子萌发的抑制活性,利用盆栽试验检测分离菌株M2-3对瓜列当寄生的防治效果。结果分离获得98株细菌,分属于28个属,马赛菌属Massilia、Pontibacter、玫瑰单胞菌属Roseomonas为优势菌属。其中,菌株M2-3与Pontibacter salisaro HMC5104T的相似度最高,为97.92%,其菌体发酵液10倍稀释液对瓜列当种子萌发抑制率为87.8%,盆栽试验表明该菌株对瓜列当防效可达36.9%,具备进一步开发可能性。     

Einfluss differenzierter Stickstoffdüngung auf Kornertrag und Backqualität von Winterweizen: (Effect of different nitrogen fertilization on yield and bread-making quality of winter wheat)

Abstract

In the “International Long-term Organic Nitrogen Fertilization Experiment” (IOSDV) the organic and mineral fertilization showed a distinct influence on yield formation and quality parameters of winter wheat, though modified by annual weather conditions. Grain yield was affected by annual weather conditions in the first place, followed by mineral N-fertilization and organic fertilization respectively. This result was due to soil conditions at the experimental site. Dry periods during the stages of spikelet formation and flowering formation, which were caused by water deficiency, reduced the yield components strongly. The yield optimum was reached at the level of 110 and 160 kg ha^?1 mineral N on the sandy soil at the location of Berlin-Dahlem. The highest nitrogen level caused non effective or slight yield depressions, especially in the “green, straw and sugar beet leaf manure” fertilization system. Organic N-fertilization (farm yard manure, straw, green manure and beet leaf fertilization) led to significant increases of winter wheat yield in the course of which biggest differences were observed when combined mineral N-fertilization was missing. The bread-making quality of B-wheat variety Flair was primarily dependent on mineral N-fertilization. Necessary values for bread wheat were predominantly obtained only, when mineral N-fertilization rates of 110?–?160 kg ha^?1 were applied. Organic N-fertilization?–?especially farmyard manure?–?improved the bread-making quality of wheat as well in treatments without mineral-N as in combination with mineral-N-fertilization.