Using Fourier transform infrared (FT-IR) absorbance spectroscopy and multivariate analysis to study the effect of chlorine-induced bacterial injury in water

The effect of chlorine-induced bacterial injury on spectral features using Fourier transform infrared (FT-IR) absorbance spectroscopy was studied using a mixed bacterial culture of (1:1) ca. 500 CFU/mL each Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 15442 in 0.9% saline. Bacterial cells were treated with 0, 0.3, or 1.0 ppm of initial free chlorine (21 degrees C, 1 h of contact time). Chlorine-injured and dead bacterial cells retained the ATR spectral properties of uninjured or live cells in the region of C-O-C stretching vibrations of polysaccharides, indicative of the cell wall peptidoglycan layer and lipopolysaccharide outer leaflet. This confirms the observations of others that extensive bacterial membrane damage is not a key factor in the inactivation of bacteria by chlorine. The bactericidal effect of chlorine caused changes in the spectral features of bacterial ester functional groups of lipids, structural proteins, and nucleic acids, with apparent denaturation reflected between 1800 and 1300 cm (-1) for injured bacterial cells. Three-dimensional principal component analysis (PCA) showed distinct segregation and clustering of chlorine-treated and untreated cells. Cells exposed to chlorine at 0.3 or 1.0 ppm could be distinguished from the untreated control 73 and 80% of the time, respectively, using soft independent modeling of class analogy (SIMCA) analysis. This study suggests that FT-IR spectroscopy may be applicable for detecting the presence of injured and viable but not culturable (VBNC) waterborne pathogens that are underestimated or not discernible using conventional microbial techniques.     

Discrimination of irradiated starch gels using FT-Raman spectroscopy and chemometrics

The effects of gamma-irradiation on starch gels were characterized at the molecular level by Fourier transform (FT) Raman spectroscopy. Starches from five different sources were gelatinized and irradiated at 3, 5, and 10 kGy using a Co60 gamma-irradiator. Gamma-irradiation effects on starch gels were noted by the C-H stretch (2800-3000 cm(-1)) and O-H stretch (3000-3600 cm(-1)) and bend (1600-1800 cm(-1)) regions of the FT-Raman spectra. FT-Raman molecular fingerprints obtained through spectral analyses were used for discrimination of the gels based on the extent of irradiation by means of two different pattern-recognition techniques: canonical variate analysis (CVA) and soft modeling of class analogy (SIMCA). A complete discrimination of irradiated starches was attained using a hybrid partial least-squares (PLS) and CVA model, using the spectral variations in the C-H stretch and O-H stretch and bend regions of FT-Raman spectra. Using the same spectral regions, SIMCA predicted 84% of samples correctly.     

The effects of live and dead roots on soil fungi in spodosolic soils of the New Jersey Pinelands

The effects of live and dead roots on soil fungi were investigated experimentally in a spodosolic soil of the New Jersey Pinelands. Field mesocosm plots were constructed to have a layer of either C- and N-rich organic soil or a vermiculite substitute overlying a layer of sandy mineral soil with a very low organic content. The plots were also supplied with live pitch pine and blueberry roots or dead pitch pine roots in varying quantities based on anturally occurring densities (half, same, and double the ambient quantities). All plots were sampled 1 year after construction (June 1991), and three more times in two subsequent years (November 1991, June 1992, June 1993). In the presence of live roots, fluorescein diacetate-determined (FDA-active) fungal hyphae, total fungal hyphae, and soil moisture decreased significantly in the organic material, while no change was associated with the dead roots. The FDA-active fungal length in the live-root plots ranged from 40 to 165 mg^-1 soil, and from 55 to 335 mg^-1 soil in the dead-root plots. While the total fungal length in live-root plots remained constant over time (3000 mg^-1 soil), the total fungal length in the dead-root plots increased from an initial value of 3000 to >4000 mg^-1 soil at the conclusion of the study. Fungal lengths in mineral soil were higher under organic material than under the vermiculite substitute. Soil moisture was higher in the presence of live roots in mineral soils, but this did not increase the fungal abundance. Inputs of dead roots did not alter the fungal abundance. Overall, we demonstrated that live and dead roots had different effects on fungal abundance in soils with contrasting qualities, and in a spodosolic forest soil, roots could have ecosystem effects very different from those in agricultural soils.Contribution No. 94-29 from the Institute of Marine and Coastal Sciences     

Characterization of irradiated starches by using FT-Raman and FTIR spectroscopy

Fourier transform infrared (FTIR) and Fourier transform Raman (FT-Raman) methods were used for rapid characterization and classification of selected irradiated starch samples. Biochemical changes due to irradiation were detected using the two vibrational spectroscopic techniques, and canonical variate analysis (CVA) was applied to the spectral data for discriminating starch samples based on the extent of irradiation. The O-H (3000-3600 cm(-1)) stretch, C-H (2800-3000 cm(-1)) stretch, the skeletal mode vibration of the glycosidic linkage (900-950 cm(-1)) in both Raman and infrared spectra, and the infrared band of water adsorbed in the amorphous parts of starches (1550-1750 cm(-1)) were employed in classification analysis of irradiated starches. Spectral data related to water adsorbed in the noncrystalline regions of starches provided a better classification of irradiated starches with 5 partial least-squares (PLS) factors in the multivariate model.     

Monitoring protein structural changes and hydration in bovine meat tissue due to salt substitutes by Fourier transform infrared (FTIR) microspectroscopy

The objective of this study was to investigate the influence of NaCl and two salt substitutes, MgSO4 and KCl, in different concentrations (1.5, 6.0, and 9.0%) on meat proteins by using Fourier transform infrared (FTIR) microspectroscopy. Hydration properties and secondary structural properties of proteins were investigated by studying the amide I, amide II, and water regions (3500-3000 cm(-1)) in FTIR spectra. By applying multivariate analysis (PCA and PLSR), differences between samples according to salt concentration and salt type were found and correlated to spectral bands. The most distinctive differences related to salt type were obtained by using the water region. It was found that samples salted with MgSO4 exhibited hydration and subsequent denaturation of proteins at lower concentrations than those salted with NaCl. Samples salted with KCl brines showed less denaturation even at the 9.0% concentration. The FTIR results were further supported by water-binding capacity (WBC) measurements.     

Rapid detection and identification of Pseudomonas aeruginosa and Escherichia coli as pure and mixed cultures in bottled drinking water using fourier transform infrared spectroscopy and multivariate analysis

Fourier transform infrared (FT-IR) spectroscopy and multivariate analysis were used to identify Pseudomonas aeruginosa and Escherichia coli ATCC 25922 inoculated into bottled drinking water. Three inoculation treatments were examined: (i) E. coli ATCC 25922 (N = 3), (ii) P. aeruginosa (N = 3), and (iii) a 1:1 (v:v) mixed culture of both P. aeruginosa and E. coli ATCC 25922 (N = 3). The control treatment was noninoculated drinking water (N = 3). Second derivative transformation and loadings plots over the range of 1800-900 cm(-1) indicate variations in the following bacterial constituents: amide I band ca. 1650 cm(-1), amide II band ca. 1540 cm(-1), phosphodiester backbone of nucleic acids ca. 1242 and 1080 cm(-1), and polysaccharide compounds ca. 1050-950 cm(-1). Cells with the different treatments were clearly segregated from a mean centered principal component analysis. By using soft independent modeling of class analogy analysis, spectra from a given treatment could be correctly classified 83-88% of the time. These results suggest that FT-IR spectroscopy can determine whether a pure culture is present, in addition to confirming that this method can discriminate between closely related bacteria based on differences in biochemical and phenotypic characteristics that can be detected in this spectral region.     

基于PCA和PNN的水稻病虫害高光谱识别

对水稻病虫害准确、快速的识别是采取病虫害防治措施的基础,同时对灾害评估也具有积极意义。该研究选用在水稻孕穗期时测定的两期受稻干尖线虫病危害的水稻叶片光谱数据和于水稻分蘖期时测定的两期受稻纵卷叶螟危害的水稻叶片光谱数据,通过对水稻叶片的光谱特征分析,选用可见光波段（490～670 nm）和短波红外波段（1 520～1 750 nm）,用主成分分析技术（PCA）对上述光谱波段进行压缩,获得主分量光谱,最后结合概率神经网络（PNN）对稻干尖线虫病和稻纵卷叶螟进行识别,结果显示对水稻病虫害的识别精度高达95.65%。研究表明,PCA和PNN相结合,可以实现对多种水稻病虫害进行快速、精确的分类识别。     

基于PCA和SRRI的潮土土壤属性与田间光谱关系研究

应用光谱分析技术可以快速无损地对土壤属性进行定量分析,是提高农田管理效率的有效途径。使用ASD Field Hand Held光谱仪测定了46个潮土土样在田间环境中350～1075nm的光谱。采用主成分分析方法和逐步线性回归方法得到了土壤反射辐射指数(SRRI)。该指数描述了土壤属性对光谱的综合作用和反射辐射能的强弱程度。结果表明潮土pH和CEC与SOC、Fe2O3、Mn和TN等对光谱的影响是不同的。采用PCA和SRRI方法进行土壤属性的光谱估计,其结果精度优于偏最小二乘回归方法(PLS),而且利用土壤属性对SRRI的贡献可准确衡量光谱估计土壤属性的可行性。     

近红外高光谱成像技术检测粮仓米象活虫

为了准确地统计出仓储害虫的密度,需对储粮活虫和死虫进行有效地判别。该文研究开发一个900～1 700 nm的近红外高光谱成像系统来检测仓储小麦活虫。用液氮低温猝死法杀死米象,在其死亡后0～7 d进行高光谱图像采集。随着粮虫死亡时间的延长,粮虫相对光谱反射率逐渐增大,到死后第5天时粮虫的光谱曲线基本趋于稳定。应用相邻波长指数法对1 320～1 680 nm之间的110个波长的高光谱图像进行分析,提取出最优波长为1 417.2 nm。提出双区域连通阈值面积比的区域生长法粮虫活虫判别方法,即当粮虫的双区域连通阈值面积比大于0.5时,应判别为活虫。结果表明,自粮虫死亡后的第2.0天开始,储粮活虫与死虫的训练样本和检验样本全部被正确识别,为实现储粮活虫的计算机视觉实时检测与分类提供依据。     

Fourier transform infrared spectroscopy and chemometric analysis of white wine polysaccharide extracts

Monovarietal white wines from Maria Gomes and Bical Portuguese Bairrada varieties were prepared according to different maceration and pectic enzyme clarification procedures. The polysaccharide-rich extracts, obtained by wine concentration, dialysis, and lyophilization, were fractionated by graded ethanol precipitation. A wide range of fractions rich in polysaccharides were obtained. Using the spectral region between 1200 and 800 cm(-)(1) of the FTIR spectra of the wine polysaccharide dry extracts, using PCA and CCA chemometric methods, it was possible to discriminate the extracts on the basis of their polysaccharide composition. Moreover, it was possible to identify the wine-making processes involved and their influence on the wine polysaccharides. Furthermore, a calibration model using a PLS1 was proposed for the quantification of mannose in the samples obtained by precipitation with 60% ethanol aqueous solutions. This information will allow an expeditious assessment and monitoring of the polysaccharide composition and modifications that occur during the wine-making processing and evolution.     

Infrared imaging of sunflower and maize root anatomy

Synchrotron radiation infrared microspectroscopy (SR-IMS) permits the direct analysis of plant cell-wall architecture at the cellular level in situ, combining spatially localized information and chemical information from IR absorbances to produce a chemical map that can be linked to a particular morphology or functional group. This study demonstrated the use of SR-IMS to probe biopolymers, such as cellulose, lignin, and proteins, in the root tissue of hydroponically grown sunflower and maize plants. Principal components analysis (PCA) was employed to reveal the major spectral variance between maize and sunflower plant tissues. The use of PCA showed distinct separation of maize and sunflower samples using the IR spectra of the epidermis and xylem. The infrared band at 1635 cm(-1), representing hydrocinnamic acid in (H type) lignin, provided a conclusive means of distinguishing between maize and sunflower plant tissues.     

Influence of Dyes on Metal Removal: a Study Using Live and Dead Cells of <Emphasis Type="Italic">Penicillium simplicissimum</Emphasis> in Single-Metal and Dye-Metal Mixtures

The metal removal efficiency of live and dead fungal cells of Penicillium simplicissimum (isolate 10, KP713758) was tested against 100 ppm toxic metals Cd, Cu, Pb, Zn and trivalent Cr in single-metal solutions and in mixtures with 50 ppm triphenylmethane (TPM) dyes (Cotton Blue, Crystal Violet, Methyl Violet, and Malachite Green). Results revealed that live cells were more effective at removing metals from single (10.8–70.0%) and dye-metal mixtures (5.3–62.2%) than dead cells (5.1–27.4%). The dyes in dye-metal mixtures influenced metal uptake capacity. All four dyes inhibited the uptake of Cd (0.9–7.1%), Zn (5.3–7.7%), Cu (5.0–25.8%) and Cr (47.3–60.7%) by live cells. The exception was the enhance removal of Pb by live cells (48.6 to 56.3–62.2%) in the presence of dye (MG or CB). Pb uptake was not affected by MV (51.8%), but was inhibited by CV (31.9%). For dead cells, uptake of metals (Cd, Cr and Zn) in single (3.2–27.4%) and dye-metal solutions (0.7–27.4%) was similar, whilst removal of Cu (6.4–13.5%) and Pb (33.6–44.0%) was inhibited by all four dyes. P. simplicissimum is concluded to have potential to remove toxic metals even in the presence of TPM dyes, with preferred use of live cells than dead cells.     

贵州岩溶峡谷地表覆盖变化的地形分异特征

岩溶峡谷是典型的喀斯特生态脆弱区,研究其地表覆盖变化对山区生态保护和国土资源空间优化具有重要意义。以贵州境内岩溶峡谷为研究区,选取2000—2020年地表覆盖数据,提取海拔、坡度、坡向三种地形因子,探究其地表覆盖变化及地形分异特征。得出以下结论:(1)2000—2020年研究区各类地表覆盖面积变化差异明显,林地、草地、水域、建设用地面积增加,耕地面积减少;(2)研究时段内随着海拔上升,研究区耕地面积呈现上升-下降-上升-下降的变化趋势;林地面积总体呈现先上升后下降趋势,峰值大致在1800～2200 m;草地和建设用地面积均存在两个相对高值区,分别出现在1200～1400 m和2200～2400 m、1200～1400 m和1800～2000 m;水域面积在小于800 m、2000～2200 m相对较高;(3)随着坡度上升,研究区耕地、林地和草地面积呈现先上升后下降趋势,分别在10°～15°、15°～20°、10°～15°出现最高值;建设用地面积随坡度增加总体呈现下降趋势;(4)在随着坡向变化中,研究区耕地、林地、草地、建设用地面积在无坡向地区分布较少;2020年建设用地面积在西南坡分布...     

Multivariate analysis of NMR and FTIR data as a potential tool for the quality control of beer

In this work, principal component analysis (PCA) is applied to the FTIR-ATR and the (1)H NMR spectra of 50 beers differing in label and type (ale, lager, alcohol-free), to identify the spectral parameters that may provide rapid information about factors affecting beer production. PCA of FTIR data resulted in the separation of beers mainly according to their alcoholic content, providing little information on components other than ethanol contributing to the variability within the samples. PCA of (1)H NMR spectra, performed on the region where major beer components resonate (3.0-6.0 ppm), resulted in the separation of samples into four groups: two groups characterized by the predominance of dextrins, one group of alcohol-free beers characterized by the predominance of maltose, and one group where glucose was found to predominate. By performing PCA on aliphatic and aromatic regions, the contribution of minor components was highlighted. In particular, most ales, lagers, and alcohol-free samples could be distinguished based on their aromatic composition, thus reflecting the high sensitivity of the low-field NMR region toward different types of beer fermentation.     

Salt-induced changes in pork myofibrillar tissue investigated by FT-IR microspectroscopy and light microscopy

FT-IR microspectroscopy and light microscopy were used to investigate pork muscle musculus semitendinosus samples, taken from three animals, that were subjected to brine salting at different concentrations (0.9, 3, 6, and 9% NaCl). Differences in spectral characteristics and in microstructure were observed in meat from animals differing in initial pH and varying salt concentrations. The FT-IR data displayed changes in the amide I region from 1700 to 1600 cm(-1). This spectral range was analyzed by principal component analysis (PCA) and partial least-squares regression (PLSR). These methods revealed correlations between the spectral data and the different animals, salt content, moisture content, pH value, and myofiber diameter. A shrinking share of alpha-helical components was related to an increase in salt concentration in the muscle. At the same time, a greater share in nonhydrogenated C=O groups (1668 cm(-1)) was related to an increase in salt concentration in the meat. The share of aggregated beta-strands differed with respect to the different animals but was not influenced by salt concentration. The meat at higher pHs (>6) had less aggregated beta-strands than that at lower pHs (5.6-5.7). It could be demonstrated that simultaneous with changes in microstructure, pH value, salt, and moisture content were alterations in the protein amide I region as measured by FT-IR microspectroscopy, revealing a relationship between these biophysical and chemical parameters and secondary protein structure attributes.     

The abundance of hollow-bearing trees in urban dry sclerophyll forest and the effect of wind on hollow development

Anthropogenic change, particularly in urban landscapes, has resulted in the fragmentation of indigenous vegetation into often small isolated ‘remnants’. The persistence of arboreal fauna in small urban remnants in part depends on the distribution and abundance of habitat resources within the remnant. We surveyed 44 small (<2.5 ha) eucalypt remnants located within the south-eastern suburbs of metropolitan Melbourne to ascertain the abundance of hollow-bearing trees, an important ecological resource. The probability of a live or dead tree containing a hollow was investigated in relation to site variables that influenced exposure to wind, a factor thought to increase the propensity of hollow formation in eucalypt trees. A total of 2678 live and 224 dead eucalypt trees were surveyed, of which 350 live (12%) and 70 dead (31%) trees were hollow-bearing. The probability of a tree being hollow-bearing was strongly positively associated with the diameter of the tree, however, past management practices have lead to a paucity of large (>80 cm DBH) trees in small urban remnants. We found that variables that measured exposure to wind were correlated with the chance that a live tree will be hollow-bearing while reducing the chance that a dead tree will be hollow-bearing. Although highly variable, the number of hollow-bearing trees contained within small urban remnants (mean of 5.8 ha⁻¹) fell well below that contained in areas of un-logged non-urban forest. Our results indicated that large numbers of hollow-bearing tree are unlikely to be recruited into urban remnants for a significant time-span and as such there is an increased importance placed on maintaining the current inventory of hollow-bearing trees for the maintenance of biodiversity in urban areas.     

Productivity and some properties of immunoglobulin specific against Streptococcus mutans serotype c in chicken egg yolk (IgY)

Hens were immunized on thighs by using whole cells of Streptococcus mutans MT8148 serotype c strain as antigen through intramuscular (im) and subcutaneous (sc) routes to investigate the difference of immunization reactions and the changes in yolk antibody activities against antigen after initial immunization. Several properties of crude IgY were examined to evaluate the stability during food processing. Results showed that the specificity of IgY of im treated hens was nearly 10 times as high as those of sc treated antibody. IgY from the hens immunized with the serotype c strain showed significant cross-reactions against serotypes e and f, while minor reactions against serotypes a, b, d, and g were observed. In thermal stability tests, IgY activity in both yolk and crude IgY decreased with the increasing temperature, from 70 to 80 degrees C, but the thermal denaturation rates between those two samples were not significantly different. The addition of high levels sucrose, maltose, glycerol, or 2% glycine displayed effective protection against thermal denaturation of IgY. Lyophilized yolk-5% gum arabic powder showed better stability against proteases.     

High-resolution nuclear magnetic resonance spectroscopy and multivariate analysis for the characterization of beer

Beer contains a very complex mixture of nutrients, which in this work are identified to some extent by high-field high-resolution nuclear magnetic resonance (NMR) one- and two-dimensional methods. The (1)H NMR spectrum of beer shows a predominance of strongly overlapped peaks arising from several carbohydrates. Minor components are clearly observed both in the aliphatic and in the aromatic regions of the spectrum. With the aid of two-dimensional methods, spectral assignment was carried out, enabling the identification of approximately 30 compounds and identifying about the same number of spin systems for further assignment. The variability of the spectral profile of beers differing in type and label was studied by principal component analysis (PCA), and it was found that, although some distinction is achieved on the basis of the aliphatic and sugar compositions, clearer separation between ales and lagers is obtained by PCA of the aromatic profiles alone. The potential of this technique as a rapid and informative quality control tool is discussed.     

滴灌苜蓿田间土壤水盐及苜蓿细根的空间分布

为了明确滴灌苜蓿土壤水、盐运移,细根分布及细根生物量动态,该文对苜蓿进行滴灌和漫灌试验,结果表明,漫灌水分集中在15 cm浅层土壤内且分布均匀,含水率在19.5%~20.5%之间。滴灌水分高值区集中在水平方向距滴头15 cm,深度为40 cm的土层中,含水率达到18.0%~20.0%。漫灌对0~25 cm深度土层盐分淋洗作用明显,土水比1:5土壤水提液的电导率由灌前的0.4~0.5 m S/cm下降到0.3 m S/cm以下;滴灌可使根区盐分下降至0.2 m S/cm,显著低于灌溉初始的盐分含量(P0.05)。与漫灌比较,滴灌苜蓿细根集中分布在水平方向距滴头0~30 cm,垂直深度0~50 cm范围内。生长季各时间节点滴灌细根总量高于漫灌,其平均值分别为211.6和198.3 g/m2。滴灌和漫灌各时间节点细根量表现出明显的波动,其范围分别在193.2~243.6和182.7~219.1 g/m2之间。在整个生长期内,滴灌活根量高于漫灌,且生长前期滴灌死根量变化较漫灌平稳。活细根和死细根之间的周转使得两者呈现出此消彼涨的状态,表明细根具有生长-凋亡-再生长的周期性。该研究可为滴灌技术在苜蓿栽培上的应用提供参考。     

FT-IR investigation of cell wall polysaccharides from cereal grains. Arabinoxylan infrared assignment

The FT-IR fingerprint of wheat endosperm arabinoxylan (AX) was investigated using a set of polysaccharides exhibiting variation of their degree of substitution and xylo-oligosaccharides comprising xylose units mono- or disubstituted by arabinose residues. Substitution of the xylose backbone by arabinose side units was more particularly studied in the 1000-800 cm(-1) spectral region, by taking advantage of second-derivative enhancement. The 920-1020 cm(-1) spectral region revealed two absorption bands at 984 and 958 cm(-1), the intensities of which varied according to the degree of substitution. Whereas the intensity of the band at 958 cm(-1) increased with the degree of substitution, that at 984 cm(-1) decreased. The second-derivative spectral data of xylo-oligosaccharides indicated that these changes could be attributed to substitution of the xylan backbone by arabinose residues, and the band at 958 cm(-1) was ascribed to the presence of disubstituted xylose residues. Principal component analysis of FT-IR spectra of model mixtures of AX, beta-glucans, and arabinogalactans suggested that it is possible to evaluate the relative proportions of the polymers and degree of substitution of AX in complex mixtures such as the cell wall of cereal grains.