Responses of four arid zone grass species from varying habitats to drought stress

The effects of 4 or 8 drought cycles on four grass species,Cenchrus pennisetiformis, Leptochloa fusca, Panicum turgidum, andPennisetum divisum were assessed in a pot experiment. There were significant differences between the species in biomass production under water stress.C. pennisetiformis andP. turgidum produced significantly greater fresh and dry matter thanP. divisum and especially thanL. fusca. L. fusca had the lowest andP. divisum highest osmotic potentials compared with the other species after the completion of 4 or 8 drought cycles. Osmotic adjustment (difference between osmotic potential of droughted/rehydrated plants and control plants) was highest inL. fusca. The stomatal conductance was significantly decreased with increased drought stress inC. pennisetiformis. The elasticity ofC. pennisetiformis, P. turgidum andP. divisum increased with increase in number of drought cycles, whereas that ofL. fusca remained unchanged.L. fusca andP. turgidum had the lowest leaf hydration of all species after 8 drought cycles. The chlorophyllsa andb in all species remained unaffected by drought treatments. The proline content ofC. pennisetiformis andL. fusca increased significantly with increased drought stress, whereas that ofP. turgidum remained unaffected after 4 or 8 drought cycles.L. fusca synthesized great amount of leaf soluble proteins during 8 drought cycles, whereasP. divisum had low protein content after 4 drought cycles. The protein contents ofC. pennisetiformis andP. turgidum remained unaffected after 8 drought cycles. The leaf epicuticular wax ofL. fusca increased consistently with increased drought stress, but leaf wax ofP. divisum increased only at the highest drought stress and that ofC. pennisetiformis andP. turgidum increased after 4 drought cycles. On the basis of these results it was established thatC. pennisetiformis andP. turgidum were the most tolerant,P. divisum intermediate, andL. fusca the most sensitive to drought stress. The osmotic adjustment did not positively correlate with the degree of drought resistance.     

Mycelial elongation and sporulation of two fungi on amended media in light or dark

Botrytis allii andCollectotrichum dematium are onion pathogens which can infect in the field and cause decay in storage. Some phenolics can hinder development of these fungi, but the effect of cytokinins is not clear. Cytokinins (kinetin or 6-benzyladenine) or phenolics (caffeic or chlorogenic acids) were added to agar at concentrations of 0 to 10^–3 M. Cultures were continuously irradiated with fluorescent light or maintained in the dark for 6 days. On unamended media, final mycelial elongation was 45 or 17.8 mm and sporulation was 28 or 10.6 × 10⁴ spores/ml forBotrytis andColletotrichum, respectively. ForBotrytis, mycelial elongation was slightly (5%) but significantly increased and sporulation increased by 21% by incubation on phenolics as compared to cytokinins. Mycelial extension ofColletotrichum was not affected by amendment. Sporulation ofColletotrichum on kinetin was 16 to 28% greater than on the other amendments. As amendments concentration increased elongation of mycelia of both fungi decreased. Sporulation ofBotrytis increased by 60% as amendment concentration increased from 0 to 10^–5 M and then decreased 25% at 10^–3 M. As amendment concentration increased from 0 to 10^–3 M, sporulation ofColletotrichum increased by 45%. Incubation in light increased mycelial extension 3 to 17% forBotrytis andColletotrichum respectively, and sporulation was increased approximately 78% for both fungi. These compounds do not appear to inhibit development of theseBotrytis orColletotrichum species in culture.     

Comparative expression analysis of genes encoding metallothioneins in response to heavy metals and abiotic stresses in rice (Oryza sativa) and Arabidopsis thaliana

To get insights into the functions of metallothionein (MT) in plant response to multiple stresses, expressions of 10 rice MT genes (OsMTs) and 7 Arabidopsis MT genes (AtMTs) were comprehensively analyzed under combined heavy metal and salt stress. OsMT1a, OsMT1b, OsMT1c, OsMT1g, and OsMT2a were increased by different heavy metals. Notably, ABA remarkably increased OsMT4 up to 80-fold. Combined salt and heavy metals (Cd, Pb, Cu) synergistically increased OsMT1a, OsMT1c, and OsMT1g, whereas combined salt and H₂O₂ or ABA synergistically increased OsMT1a and OsMT4. Heavy metals decreased AtMT1c, AtMT2b, and AtMT3 but cold or ABA increased AtMT1a, AtMT1c, and AtMT2a. AtMT4a was markedly increased by salt stress. Combined salt and other stresses (Pb, Cd, H₂O₂) synergistically increased AtMT4a. Taken together, these findings suggest that MTs in monocot and dicot respond differently to combined stresses, which provides a valuable basis to further determine the roles of MTs in broad stress tolerance.     

Effect of Bradyrhizobium, VA mycorrhiza and fertilisers on seed composition of groundnut

A field experiment was carried out to investigate the effect of Bradyrhizobium and mycorrhizal (Glomus sp.) inoculation compared to adding urea and super phosphate on proximate composition, in vitro protein digestibility (IVPD) and tannin content of groundnut. The results showed that mycorrhizal inoculation and/or superphosphate significantly (P≤ 0.05) increased both oil and protein content of groundnut seeds. Bradyrhizobium and/or nitrogen fertiliser significantly (P≤ 0.05) increased protein content and significantly decreased the oil content. Bradyrhizobium and/or mycorrhizal inoculation significantly (P≤ 0.05) increased the ash, crude fibre, IVPD and tannin content. Biological and chemical fertilisers significantly (P≤ 0.05) increased IVPD. Superphosphate fertilisers significantly (P≤ 0.05) increased the tannin content. The moisture content was not affected by any treatment.     

Genes involved in the immediate early response and epithelial-mesenchymal transition are regulated by adipocytokines in the female reproductive tract

Obesity increases the risk of female reproductive tract cancers, but the underlying mechanistic link between the two is ill‐defined. Thus, the objective of the current study was to identify obesity‐dependent changes in the expression of immediate early (IE) genes that contribute to cell proliferation and differentiation, and epithelial–mesenchymal transition (EMT) genes that promote cell migration. When HeLa cells were treated for 0–48 hr with IGF‐1, leptin, TNFα, or IL‐6, each individual adipocytokine altered the abundance of IE (cJUN, cFOS, and cMYC) and EMT (SNAI1, SNAI2, and TWIST1) mRNA abundance. For example, IGF‐1 increased cJUN and cFOS and decreased cMYC; leptin increased cFOS; IL‐6 increased cFOS and cMYC; and TNFα increased cJUN and cFOS mRNA abundance. Likewise, EMT gene expression was altered by IGF‐1, TNFα, and IL‐6. SNAI1 was increased by IGF‐1 and IL‐6; SNAI2 was increased by IGF‐1 and TNFα; and TWIST1 was increased by TNFα and IL‐6. Chronic exposure to adipocytokines also altered EMT gene expression in the whole uterus of obese compared to normal‐weight mice. Specifically, there was no difference in cJun, cFos, or cMyc mRNA abundance between normal‐weight and obese animals. Snai1, Snai2, and Twist1 mRNA abundance, however, was increased in the uterus of obese females and correlated with increased circulating IGF‐1 levels. These data indicate that obesity‐dependent alterations in adipocytokine levels regulate the expression of genes associated with cell proliferation and migration, and therefore may provide a plausible mechanism for obesity‐dependent increases in cancers of the female reproductive tract. Mol. Reprod. Dev. 79:128–137, 2012. © 2011 Wiley Periodicals, Inc.     

Asexual reproductive organ-specific expression of the glyceraldehyde-3-phosphate dehydrogenase 2 gene of Pilobolus crystallinus

Pilobolus crystallinus has three putative glyceraldehyde-3-phosphate dehydrogenase (gapdh) genes (pcgapdh1, pcgapdh2 and pcgapdh3). The results of this study demonstrate that expression of pcgapdh2 was increased by irradiation and that this increased expression was correlated with the formation of asexual reproductive organs (trophocysts). Interestingly, expression of pcgapdh2 was restricted to trophocysts. The formation of trophocysts was likely promoted by light, and the expression of pcgapdh2 was increased as a result of trophocyst formation. This is the first report that shows the regulation of a gapdh gene in an organ-specific manner in fungi.     

Effect of plant population on the production and distribution of dry matter in maize

Grain and total dry weight of maize (Zea mays L.) at final harvest increased by about 50% and 30%, respectively, when the population was increased from 23000 to 48000 plants/ha, but did not increase further with population up to 74000/ha. Between 6 and 10 weeks after sowing, crop growth rate (C) increased by about 40% with increase in leaf-area index (L) from 2 to 5·5, despite a concomitant increase in moisture stress. Immediately after flowering, which occurred at 10–11 weeks, C increased up to the greatest L attained, 6·7, and would probably have reached a maximum, with L about 7, when nearly all the incident light would be intercepted by foliage. Later, the L at which C was maximal decreased, probably because the photosyhthetic efficiency of leaves decreased faster with time as L increased; 18 weeks after sowing, when L varied between 3 and 5·5, C was maximal when L was 5. The proportion of grain in the dry matter accumulated after flowering increased from 73% when population was 23000/ha to 82% when it was 60000–74000/ha. Stem weight increased until 3–4 weeks after flowering, then remained constant when population was 23000/ha, but decreased in denser populations. The fraction of the ear consisting of grain increased with population.     

沙芥属植物活性氧清除系统对干旱胁迫的响应

以沙芥属植物沙芥和斧形沙芥幼苗为试材,采用盆栽控水干旱方法,分析其在不同干旱胁迫强度下根和叶的活性氧水平、抗氧化酶活性和抗氧化剂含量的变化,并利用隶属函数法和抗旱系数法综合评价沙芥和斧形沙芥的抗旱性。结果表明: （1）随着干旱胁迫程度的加剧,沙芥和斧形沙芥的根和叶中O^-·₂产生速率及·OH、H₂O₂、MDA含量总体呈逐渐升高的趋势,且干旱胁迫下沙芥比斧形沙芥产生了更多的ROS和MDA。（2）随着干旱胁迫程度的加剧,沙芥和斧形沙芥的根和叶中POD、APX、GST活性及叶中GR活性均先升高后降低,叶中的SOD活性以及根中GR、GPX活性均先降低后升高,根和叶中的CAT活性、叶中的GPX活性和根中SOD活性均逐渐升高;但根和叶中的SOD、POD、CAT活性在各干旱处理下均表现为斧形沙芥高于沙芥。（3）沙芥和斧形沙芥的根和叶中AsA含量随着干旱胁迫程度的加剧而先升高后降低,GSH含量逐渐升高,CAR含量逐渐降低,而VE含量在叶中逐渐升高,在根中却逐渐降低;但斧形沙芥比沙芥合成更多的AsA和GSH,其植物体内AsA GSH循环系统能清除更多的ROS。（4）沙芥和斧形沙芥的根和叶中总抗氧化能力（T AOC）均随着干旱加剧逐渐增强,且斧形沙芥的总抗氧化能力强于沙芥;活性氧清除系统的平均隶属度和综合抗旱系数显示,轻度干旱胁迫下沙芥抗旱性强于斧形沙芥,中度和重度干旱胁迫下斧形沙芥的抗旱性强于沙芥。研究认为,在干旱胁迫条件下,斧形沙芥根叶中ROS和MDA含量明显低于沙芥,而其大部分抗氧化酶活性和抗氧化剂含量高于沙芥,斧形沙芥植株体内抗氧化系统表现出更强的活性氧清除能力,从而表现出更强的抗旱性。     

华南地区六种蕨类植物耐旱性研究

利用盆栽控水法研究了华南毛蕨、蜈蚣蕨、线羽凤尾蕨、毛叶铁线蕨、长叶肾蕨和普通针毛蕨6种华南地区常见蕨类的耐旱性,测定了植株在自然干旱下的土壤绝对含水量、叶绿素SPAD值、叶片相对含水量和气体交换参数等指标变化。结果表明:随干旱胁迫加剧,叶片相对含水量总体呈下降趋势,其中普通针毛蕨、蜈蚣蕨和长叶肾蕨下降不明显,华南毛蕨降幅最大。叶绿素SPAD值随干旱加剧显著下降,其中华南毛蕨和长叶肾蕨下降幅度较小,蜈蚣蕨下降幅度较大。净光合速率、气孔导度和蒸腾速率随干旱加剧而不断下降,其中普通针毛蕨和蜈蚣蕨下降幅度较小,华南毛蕨下降幅度较大。然而,胞间CO2浓度随着干旱的加剧而不断上升,其中线羽凤尾蕨上升幅度最大,蜈蚣蕨和普通针毛蕨上升幅度较小。以各指标的平均变化速率为原始数据进行隶属函数法分析得出,六种参试蕨类植物的耐旱能力大小依次为蜈蚣蕨普通针毛蕨长叶肾蕨毛叶铁线蕨华南毛蕨线羽凤尾蕨。     

Divergent trends in life‐history traits between Atlantic salmon Salmo salar of wild and hatchery origin in the Baltic Sea

Four Atlantic salmon Salmo salar stocks in the Baltic Sea, varying in their breeding history, were studied for changes in life‐history traits over the years 1972–1995. Total length (L_T) at age of captured (L_TC) fish had increased throughout the study period, partly due to increased temperature and increased L_T at release, (L_TR) but also due to remaining cohort effects that could represent unaccounted environmental or genetic change. Simultaneously, maturation probabilities controlled for water temperature, L_TC and L_TR had increased in all stocks. The least change was observed in the River Tornionjoki S. salar that was subject only to supportive stockings originating from wild parents. These results suggest a long‐term divergence between semi‐natural and broodstock‐based S. salar stocks. Increased L_T at age explained advanced maturation only marginally, and it remains an open question to what extent the generally increased probabilities to mature at early age reflected underlying genetic changes.     

Gelsolin rs1078305 and rs10818524 polymorphisms were associated with risk of oral squamous cell carcinoma in a Chinese Han population

Background: Gelsolin (GSN) is one of the most abundant actin-binding proteins, and is involved in cancer development and progression.

Patients and methods: A hospital-based case-control study including 201 patients with OSCC and 199 healthy controls was conducted. Seventeen single-nucleotide polymorphisms (SNPs) of GSN were investigated by Sequenom Mass ARRAY and iPLEX-MALDI-TOF technology.

Results: Through comparison of the 17 SNPs on GSN gene between the two groups, SNP rs1078305 and rs10818524 were verified to be significantly associated with an increased risk of OSCC. For GSN rs1078305, the TT genotype was associated with increased risk for OSCC (OR?=?1.92, 95% CI?=?1.11–3.32, p?=?0.028). CT/TT variants were also associated with increased risk for OSCC compared to the CC genotype (OR?=?1.83, 95% CI?=?1.25–3.84, p?=?0.032).

Conclusion: The rs1078305 and rs10818524 SNPs of GSN were associated with increased risk for OSCC development in a Chinese Han population.     

Photosynthesis,Transpiration, and Water Use Efficiency of Caragana microphylla,C. intermedia,and C. korshinskii

In the order C. microphylla — C. intermedia — C. korshinskii, compensation irradiance, saturation irradiance, and optimum temperature for photosynthesis increased, net photosynthetic rate (P _N) at low irradiance and low temperature decreased, optimum air humidity decreased, and P _N at low air humidity increased. Daily cumulative value of P _N increased while daily cumulative value of transpiration (E) decreased, and hence water use efficiency (WUE =P _N/E) increased. Diurnal course of P _N of C. microphylla was a double-peak curve, but the second peak in the curves of C. intermedia and C. korshinskii was not visible. These physiological characteristics are biological basis for the geographical distribution of these three Caragana species, and are in relation to water conditions of their habitats and distinctiveness in leaf hair of plant.     

The biosynthesis of taurine fromN-acetyl-l-cysteine and other precursorsin vivo and in rat hepatocytes

Summary The synthesis of taurine fromN-acetylcysteine has been examined in ratsin vivo and in rat hepatocyte suspensionsin vitro. In ratsin vivo, administration ofN-acetylcysteine significantly increased urinary taurine (3 fold) 24h after dosing and liver glutathione levels. Liver taurine was not increased significantly. In hepatocytes incubated in the presence ofN-acetylcysteine, glutathione concentration increased to a maximum after 1 hour but the increase was not dependent on the concentration ofN-acetylcysteine. In contrast, after an initial lag phase, taurine synthesis increased in relation to the concentration ofN-acetylcysteine and continued for 3 hours. Glutathione synthesis seems to be preferential to taurine synthesis. Taurine synthesis from cysteine sulphinate was greater and from hypotaurine was greatest and maximal after 1 hour. Implications for the mechanism of protection byN-acetylcysteine are discussed.     

Increased fear learning,spatial learning as well as neophobia in Rgs2−/− mice

Anxiety disorders result from a complex interplay of genetic and environmental factors such as stress. On the level of cellular signaling, regulator of G protein signaling 2 (Rgs2) has been implicated in human and rodent anxiety. However, there is limited knowledge about the role of Rgs2 in fear learning and reactivity to stress. In this study, Rgs2^?/? mice showed increased fear learning, male mice displayed increased contextual and cued fear learning, while females showed selectively enhanced cued fear learning. Male Rgs2^?/? mice displayed increased long‐term‐contextual fear memory, but increased cued fear extinction. Learning in spatial non‐aversive paradigms was also increased in Rgs2^?/? mice. Female, but not male mice show increased spatial learning in the Barnes maze, while male mice showed enhanced place preference in the IntelliCage, rendering enhanced cognitive function non‐specific for aversive stimuli. Consistent with the previous results, Rgs2 deletion resulted in increased innate anxiety, including neophobic behavior expressed as hypolocomotion, in three different tests based on the approach‐avoidance conflict. Acute electric foot shock stress provoked hypolocomotion in several exploration‐based tests, suggesting fear generalization in both genotypes. Rgs2 deletion was associated with reduced monoaminergic neurotransmitter levels in the hippocampus and prefrontal cortex and disturbed corresponding GPCR expression of the adrenergic, serotonergic, dopaminergic and neuropeptide Y system. Taken together, Rgs2 deletion promotes improved cognitive function as well as increased anxiety‐like behavior, but has no effect on acute stress reactivity. These effects may be related to the observed disruption of the monoaminergic systems.     

Chaoborus and fish-mediated influences on Daphnia longispina population structure,dynamics and life history strategies

Summary This study examined the long term effects of predation by larvae of the midge Chaoborus and simulated fish predation on experimental Daphnia longispina populations. Chaoborus predation, relative to fish predation, led to populations composed of larger individuals as a whole, larger egg-bearing individuals, and a larger primiparous instar. Daphnia retained helmets beyond the first instar in response to the presence of Chaoborus. Both types of predation, relative to predator-free controls, reduced prey population size and rates of increase, but increased population death rates. The reduction in population size due to predation led to increased resource availability for individuals remaining in the populations and increased individual fecundity in the predation treatments. The differences noted between the Chaoborus, fish, and control treatments increased with predation intensity.     

Bacterial community structure within an activated sludge reactor added with phenolic compounds

Biodegradation of phenolic compounds in bioreactors is well documented, but the changes in the bacterial populations dynamics during degradation were not that often. A glass bubble column used as reactor was inoculated with activated sludge, spiked with 2-chlorophenol, phenol and m-cresol after 28 days and maintained for an additional 56 days, while the 16S rRNA gene from metagenomic DNA was monitored. Proteobacteria (68.1%) dominated the inoculum, but the bacterial composition changed rapidly. The relative abundance of Bacteroidetes and Firmicutes decreased from 4.8 and 9.4 to <0.1 and 0.2% respectively, while that of Actinobacteria and TM7 increased from 4.8 and 2.0 to 19.2 and 16.1% respectively. Phenol application increased the relative abundance of Proteobacteria to 94.2% (mostly Brevundimonas 17.6%), while that of Bacteroidetes remained low (1.2%) until day 42. It then increased to 47.3% (mostly Leadbetterella 46.9%) at day 84. It was found that addition of phenolic compounds did not affect the relative abundance of the Alphaproteobacteria initially, but it decreased slowly while that of the Bacteroidetes increased towards the end.

     

Ameliorative Effect of Chlormequat Chloride and IAA on Drought Stressed Plants of <Emphasis Type="Italic">Cymbopogon Martinii</Emphasis> and <Emphasis Type="Italic">C. winterianus</Emphasis>

Responses of Cymbopogon martinii and C. winterianus to drought stress and chlormequat chloride and IAA application are compared. These two species are important source of essential oil production in drought regions. For both species and their cultivars relative water content (RWC), herbage yield and oil amount decreased under drought, while oil biosynthesis increased. Oil concentration increased significantly under drought in C. winterianus while peroxidase activity increased in C. martinii. Amount of geraniol increased under drought stress in C. martinii while citronellal and geraniol accumulation decreased in C. winterianus. Ameliorative effects of chlormequat chloride and IAA were observed in drought stressed plants of both species. Herbage yield increased significantly in chlormequat chloride and IAA treated stressed plants of C. winterianus, while oil concentration increased in C. martinii. Ameliorative effect of IAA in increasing oil yield was significant in drought stressed plants of both the species. Changes in various morpho-physiological traits indicated that chlormequat chloride and IAA can partially alleviate the detrimental effect of drought in these aromatic grasses.     

A gene, SMP2, involved in plasmid maintenance and respiration in Saccharomyces cerevisiae encodes a highly charged protein

Summary The smp2 mutant of Saccharomyces cerevisiae shows increased stability of the heterologous plasmid pSR1 and YRp plasmids. A DNA fragment bearing the SMP2 gene was cloned by its ability to complement the slow growth of the smp2 smp3 double mutant (smp3 is another mutation conferring increased stability of plasmid pSR1). The nucleotide sequence of SMP2 indicated that it encodes a highly charged 95 kDa protein. Disruption of the genomic SMP2 gene resulted in a respiration-deficient phenotype, although the cells retained mitochondrial DNA, and showed increased stability of pSR1 like the original smp2 mutant. The fact that the smp2 mutant is not always respiration deficient and shows increased pSR1 stability even in a rho ⁰ strain lacking mitochondrial DNA suggested that the function of the Smp2 protein in plasmid maintenance is independent of respiration. The SMP2 locus was mapped at a site 71 cM from lys7 and 21 cM from ilv2/SMR1 on the right arm of chromosome XIII.