Kinesin and dynein move a peroxisome in vivo: a tug-of-war or coordinated movement?

We used fluorescence imaging with one nanometer accuracy (FIONA) to analyze organelle movement by conventional kinesin and cytoplasmic dynein in a cell. We located a green fluorescence protein (GFP)-tagged peroxisome in cultured Drosophila S2 cells to within 1.5 nanometers in 1.1 milliseconds, a 400-fold improvement in temporal resolution, sufficient to determine the average step size to be approximately 8 nanometers for both dynein and kinesin. Furthermore, we found that dynein and kinesin do not work against each other in vivo during peroxisome transport. Rather, multiple kinesins or multiple dyneins work together, producing up to 10 times the in vitro speed.     

Effect of environmental factors on estrus synchronization and artificial insemination success in farmers flock in sheep under semi-arid tropical region

Environmental cues in the different seasons might influence the estrus and lambing percentages. The present study was conducted to assess the effect of environmental factors on estrus synchronization (ES) and artificial insemination success in sheep . During the period from 2012 to 2017, a total of 1,197 ewes of Kheri and Malpura breeds of 34 farms originating from 10 villages were synchronized for estrus and then fixed-time artificial insemination (FTAI) was done. Oestrous synchronization was done by intravaginal progesterone sponges and eCG protocol. Fixed-time cervical insemination was performed 48 and 56 hr after sponge removal in ewes exhibiting estrus, using liquid chilled semen containing 100 million sperm per dose of Patanwadi/Malpura rams. Mean sunshine hours, maximum and minimum ambient temperatures, temperature amplitude, mean relative humidity (RH), temperature-humidity index (THI), mean temperature during sponge-in to sponge-out—12-day period, sponge-out and next day, AI day and AI to next 15 days have been calculated. The estrus response and lambing percentage were higher (p < .05) when ES and FTAI were done during hot-humid with rainfall season. Successful (p < .05) ES occur when the minimum temperature was higher in cold-humid season, and the sunshine hour was higher in hot-humid with scanty rainfall season during sponge-in to sponge-out period. The success of the lambing percentage was higher (p < .05) when maximum temperature, minimum temperature, mean temperature and THI was higher on the day of AI and the next 15-day period, irrespective of the season. The success of FTAI indicates the adaptability of the local breed to tolerate the harsh climate of the hot semi-arid region without much hindrance in lambing percentages.     

Delineating soil nutrient management zones based on optimal sampling interval in medium- and small-scale intensive farming systems

Precision Agriculture - Soil nutrients vary greatly and information regarding their spatial-temporal variability is critical for achieving site-specific nutrient management. However, the problem is...     

Potassium isotherm partitioning based on modified quantity‐intensity relation and potassium buffering characterization of soils of North India

Background : Potassium (K) availability in soil and plant uptake is restrained by the dynamic interactions among the different pools of K. Aims : To understand these interactions, a study was undertaken to assess the quantity–intensity (Q/I) and buffering characteristics of rainfed maize (Zea mays L.) growing soils. Ten contrasting soils were evaluated for K partitioning changes in exchangeable K (ΔEK) and non‐exchangeable K (ΔNEK) pools in the soil‐solution phase and buffering characteristics using a modified version of Q/I approach. Results : The partitioned Q/I isotherms showed strong adsorption with the increase in K concentration ratio (CR^K) and the changes due to ΔEK were higher than changes due to ΔNEK. Total buffering capacity (PBC^K) significantly correlated (r = 0.92, p <0.01) with clay content with a major share contributed by buffering capacity owing to non‐exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{NEK}}^K$) rather than exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{EK}}^K$). The fixation capacity (β) factor, the magnitude of added K converted into a non‐exchangeable pool, ranged from 41 to 63%, whereas release (α) factor, the magnitude of added K converted to the exchangeable pool, ranged from 19 to 36%. Both threshold solution K (CK_r) and threshold exchangeable K (EK_r) values were found to be high in Satran clay loam (S2) and lower in Doon silty clay loam (S3) soils. The equilibrium exchangeable K (EK_o) was found close to minimum exchangeable K (E_min) in Doon silty clay loam (S3) and Babaweyl sandy clay loam (S1) soils and overall E_min constituted about 8.94 to 0.57% of the EK_o. Conclusion : It may be concluded that K Q/I isotherm partitioning provides a valuable insight to assess the dynamic relations. The ratio of α/β (K recharge index) could be used to evaluate the K enrichment capacity of soil to K additions while EK_r and E_min can be potentially useful in the elucidation of exchangeable K as K fertility index especially in soils with poor K fertilizer management.     

High prevalence of antibiotic resistance in pathogenic Escherichia coli from large- and small-scale poultry farms in Bangladesh

Antibiotic resistance in avian bacterial pathogens is a common problem in the Bangladesh poultry industry. The aim of the present study was to provide information on the present status of antibiotic resistance patterns in avian pathogenic Escherichia coli in Bangladesh. Of 279 dead or sick poultry of different ages, 101 pathogenic E coli strains isolated from broilers and layer hens with colibacillosis infections were screened to determine phenotypic expression of antimicrobial resistance against 13 antibiotics used in both veterinary and human medicine in Bangladesh. Of 101 pathogenic E. coli isolates, more than 55% were resistant to at least one or more of the tested compounds, and 36.6% of the isolates showed multiple-drug-resistant phenotypes. The most common resistances observed were against tetracycline (45.5%), trimethoprim-sulphamethoxazole (26.7%), nalidixic acid (25.7%), ampicillin (25.7%), and streptomycin (20.8%). Resistance to ciprofloxacin (12.9%), chlormaphenicol (8.9%), nitrofurantoin (2%), and gentamicin (2%) was also observed, and none of the isolates were resistant to tigecycline as well as extended spectrum beta-lactamase (ESBL) producers. One isolate was resistant to cefuroxime (1%), cefadroxil (1%), and mecillinam (1%) but was not an ESBL producer. Resistance rates, although significant in Bangladeshi isolates, were found to be lower than those reported for avian isolates from the Republic of Korea and clinical, avian, and environmental isolates from Bangladesh. The high level of antibiotic resistance in avian pathogens from Bangladesh is worrisome and indicates that widespread use of antibiotics as feed additives for growth promotion and disease prevention could have negative implications for human and animal health and the environment.     

2种昆虫病原真菌对草地贪夜蛾体表侵染模式的扫描电镜观察

【目的】在前期筛选获得对草地贪夜蛾高效致病真菌球孢白僵菌（Beauveria bassiana）菌株GZSL-1和玫烟色虫草（Cordyceps fumosorosea）菌株IFCF01的基础上,进一步明确2株菌株在草地贪夜蛾体表的侵染模式,为阐明菌株致病机理,提高昆虫病原真菌对草地贪夜蛾的防效提供理论依据。【方法】利用扫描电镜观察草地贪夜蛾2龄幼虫分别接种菌株GZSL-1和IFCF01（孢子悬浮液浓度为1.0×107孢子/mL）后分生孢子在幼虫体表附着、萌发、穿透和增殖的过程。【结果】菌株GZSL-1和IFCF01萌发后均可形成附着胞,草地贪夜蛾幼虫体表结构对2株菌株分生孢子萌发、附着和穿透芽管长度有不同程度的影响。2株菌株在各结构区均有较高的萌发率（> 90.00%）和附着胞率（> 80.00%）,在平缓结构区比瘤状突起结构区观察到更短的穿透芽管。在各结构区,菌株GZSL-1形成的穿透芽管长度均短于菌株IF-CF01相应的芽管长度,在平缓结构区,菌株GZSL-1的穿透芽管长度显著短于菌株IFCF01（P<0.05）。菌株GZSL-1和IFCF01分生孢子接种后分别在16和8 h内萌发,在24和32 h内普遍出现穿透结构穿透草地贪夜蛾幼虫体壁。2株菌株的初级和次级分生孢子分别在接种后72和96 h内出现。【结论】扫描电镜观察证实球孢白僵菌菌株GZSL-1和玫烟色虫草菌株IFCF01对草地贪夜蛾具有高致病性,揭示了病原真菌分生孢子在草地贪夜蛾虫体上的侵染过程,结果为后续2株菌株的改良及田间应用打下理论基础。     

Comparison of net ecosystem CO2 exchange in two peatlands in western Canada with contrasting dominant vegetation, Sphagnum and Carex

Net ecosystem carbon dioxide exchange was measured in two contrasting peatlands in northern Alberta, Canada using the eddy covariance technique during the growing season (May–October). Sphagnum spp. made up approximately 66% of the total LAI (1.52 m² m⁻²) at the poor fen and the total N content of Sphagnum capitula was 7.8 mg g⁻¹ at the peak of the growing season. In contrast, the dominant plant species at the extreme-rich fen site, the perennial sedge, Carex lasiocarpa, accounted for approximately 60% of the total LAI (1.09 m² m⁻²), and had leaf total N content of 19.3 mg g⁻¹ at peak biomass. In addition, the peak aboveground biomass was higher at the poor fen (230.9 g m⁻²) than at the extreme-rich fen (157.1 g m⁻²). Both sites had maximum daily rates of net CO₂ uptake of approximately 5 μmol m⁻² s⁻¹, and typical nighttime rates of CO₂ loss of approximately 2 μmol m⁻² s⁻¹ during the peak of the growing season. Calculations of maximum photosynthetic and respiratory capacity were consistently higher at the extreme-rich fen. The poor fen was a net sink for CO₂ during 4 of the 6 months (peaking at 44 g C m⁻² in July), while only slight net losses of CO₂ (3 g C m⁻²) occurred in May and September. In contrast, the extreme-rich fen was calculated to be a significant net sink for CO₂ only during 2 months of the growing season (peaking at 30 g C m⁻² in August), while significant net losses of CO₂ occurred in May (8 g C m⁻²) and in October (13 g C m⁻²). The plant species at the poor fen site were active earlier and later in the growing season, while it took longer for C. lasiocarpa to develop leaf tissue, and leaf senescence and reduction in photosynthetic activity occurred earlier in the fall at the extreme-rich fen. When integrated over the 6-month growing season, the poor fen was a net sink (90 g C m⁻²) that was three times larger than the extreme-rich fen (31 g C m⁻²). The ratio of cumulative total ecosystem respiration to gross primary production was 0.7 at the poor fen and 0.9 at the extreme-rich fen.     

The possible role of organic acids as allelochemicals in Tamarindus indica L. leaves

Tamarindus indica L. is well known for its acidic nature and allelopathic potential, but to date, little is known about its organic acids playing their role as allelochemicals. Hence, in the present study, identification, quantification, and contribution of organic acids present in its leaf extract were conducted using the principle of bioassay-guided procedure. High pressure liquid chromatography identified four organic acids, viz. citric, malic, oxalic, and tartaric acids, in its leaf aqueous extract with the predominance of oxalic acid (7.5 g kg^?1 leaves fresh weight) followed by tartaric acid (7.3 g kg^?1). The allelopathic activity of identified acids and aqueous extract was evaluated on lettuce seedlings growth based on the specific activity (EC₅₀). The crude extract reduced radicle growth more adversely than hypocotyl at the concentration of 2.5 g L^?1 (EC₅₀). It hindered the normal physiological growth process through weak and curly seedlings, and necrosis of their tips. Among the identified acids, oxalic acid had the highest specific activity (40 mg L^?1) and citric acid had the lowest (>1000 mg L^?1). As a consequence of its high contents, the total activity, a function of specific activity and concentration, of oxalic acid (188) was found higher followed by tartaric acid (146). The contribution of both acids influencing the specific activity of the crude extract was then turned out to be 74%. To the best of our knowledge, this is the first report identifying the oxalic and tartaric acids as growth inhibitors in tamarind leaves and quantifying their contribution in its allelopathic expression. Based on the total activity, the results suggested that oxalic and tartaric acids are the major allelochemicals in tamarind leaves. The allelopathic potential of these acids might promote the development of natural herbicides as an alternative to the synthetic ones in a most sustainable manner.     

A serological survey of leptospirosis in cats

A serological survey of 225 cats from different parts of the NorthIsland was conducted using 11 leptospiral serovar antigens. Twenty (8.8%) of the sera gave titres to the microagglutination test.The prevalence of titres to the serovars were as follows: five (2.22%) to copenhageni, five (2.22%) to hardjo, four (1.77%) to ballum, four (1.77%) to pomona, one (0.44%) to balanica and one (0.44%) to canicola; no titres to tarassovi, bataviae, pyrogenes and australis were recorded. It is hypothesised that prey-predator transmission between cats and rodents is responsible for infections with serovars copenhageni and ballum. Infections with the other serovars are presumed to result from contact with infected animals or a contaminated environment.     

Immunodetection of coproantigens for the diagnosis of amphistomosis in naturally infected Indian Water Buffalo,Bubalus bubalis

The infection of gastrointestinal helminths in livestock is routinely diagnosed by microscopical examination of faecal samples for the presence of ova/eggs but this approach becomes ineffective for the seasonally egg producing trematodes. Therefore, an alternative approach to detect the coproantigens of liver and rumen amphistomes, Gigantocotyle explanatum and Gastrothylax crumenifer respectively, infecting Indian water buffalo Bubalus bubalis, was undertaken using ELISA, immunodot and countercurrent immunoelectrophoresis (CCIEP). The hyperimmune polyclonal antisera were separately raised in rabbits against excretory/secretory (ES) antigens of both the flukes under study. An overall 70% buffalo faecal samples were tested positive for G. crumenifer and 75% for G. explanatum in Aligarh region. The ELISA results reflected higher infection intensity among individual buffaloes that was also observed at necropsy. Using the respective homologous hyperimmune antiserum, 55% buffaloes tested positive for G. crumenifer and 65% positive for G. explanatum in immunodot assay. Further, the faecal samples with high absorbance values in ELISA and strong immunodot reaction tested positive in CCIEP. The analysis of CCIEP result revealed two and one precipitin bands in G. crumenifer and G. explanatum respectively, indicating prominent antigenic differences in the coproantigens of these two parasites. Taken together, it is suggested that polyclonal antibodies could be conveniently used for the detection of coproantigens by ELISA and immunodot methods, particularly during the non-egg producing phase of the seasonally regulated reproductive cycle of the rumen amphistome G. crumenifer. It is concluded that the coproantigen detection is a good alternative over conventional method for the diagnosis of amphistomosis in livestock; however, further studies are required on a larger sample size of field buffaloes to augment the reproducibility of the present results.