Interactions between heavy metals and glucosinolates as defense mechanisms in Thlaspi caerulescens

Hyperaccumulator plant species grow in metalliferous soils and accumulate exceedingly high concentrations of metals. They are increasingly studied because of their potential for cleaning up land contaminated with heavy metals, but another aspect of study relates to the reason for hyperaccumulation. The most accepted hypothesis over the last few decades is the ‘elemental defence’ hypothesis, which states that high levels of metals defend the plant against herbivores. Whilst some of the literature is contradictory, some is supportive. An added complication is that many hyperaccumulators belong to the Brassicaceae and produce glucosinolates as organic defences against herbivory. The question to be answered is whether metals or glucosinolates act as the primary defence in these plants and the most recent suggestion is the ‘joint effects’ hypothesis, which states that both classes of chemical work together to benefit the plant and protect it from herbivores. This study investigates these hypotheses and utilized three experimental systems. The hyperaccumulator studied was Thlaspi caerulescens (Gange ecotype) which hyperaccumulates zinc. Plants were grown in a series of glasshouse experiments at a range of soil zinc amendments. There was a positive relationship between soil and foliar zinc; optimum growth occurred at 2000 mg Zn kg-1 soil and this equated to approximately 8000 mg Zn kg-1 shoot, although plants took up as much as 14000 mg Zn kg-1 shoot tissue at higher levels of soil amendment. The herbivore systems studied were generalist thrips (Franklinella occidentalis) and the specialist cabbage whitefly (Aleyrodes proletella). In addition, artificial damage caused by clipping served as a positive control. Four aromatic glucosinolates were extracted from T. caerulescens and two were identified as benzyl and p-OH-benzyl. Glucosinolates were synthesized 32 hours after damage occurred and reached a maximum concentration after 48 hours. Generally, lower concentrations of glucosinolates were observed in plants with higher foliar Zn concentrations and vice versa. However, when plants were subjected to a sustained and heavy herbivore attack, as was the case when thrips infested the plants, glucosinolate production occurred irrespective of foliar Zn concentration. This observation supports the ‘joint effects’ hypothesis, which states that both defences work in tandem and enhance overall defence. Nitrogen was an important component that directed herbivore response. Thrip feeding damage was negatively correlated with foliar nitrogen whilst cabbage whitefly (CWF) benefitted from higher N. Nitrogen was positively correlated with glucosinolate concentrations and glucosinolate content negatively affected the generalist thrips but not the specialist CWF. Data were analysed by accumulated general linear regression and the explanatory model for thrip feeding was C/N ratio + GS + Zn whilst the explanatory model for CWFs was C/N ratio + Zn. Use of the specialist feeder (CWF) allowed for study of the effects of zinc without glucosinolates confounding the results since the CWF was unaffected by foliar glucosinolates. Zinc acted as a defence against CWF but only at high concentrations. The data taken together show that zinc acts as a defence against herbivores that are unaffected by glucosinolates, but only at high concentrations. Zinc also defends the plant against generalist thrips, but glucosinolates are more influential in this case. This might be because of the severe and sustained damage that these plants suffered and systemic effects (i.e. higher concentrations of glucosinolates in undamaged leaves relative to attacked leaves) suggests flexibility in the Zn-glucosinolate relationship. The overall conclusion is in support of the joint effects hypothesis

Interactions between heavy metals and glucosinolates as defense mechanisms in Thlaspi caerulescens

Hyperaccumulator plant species grow in metalliferous soils and accumulate exceedingly high concentrations of metals. They are increasingly studied because of their potential for cleaning up land contaminated with heavy metals, but another aspect of study relates to the reason for hyperaccumulation. The most accepted hypothesis over the last few decades is the ‘elemental defence’ hypothesis, which states that high levels of metals defend the plant against herbivores. Whilst some of the literature is contradictory, some is supportive. An added complication is that many hyperaccumulators belong to the Brassicaceae and produce glucosinolates as organic defences against herbivory. The question to be answered is whether metals or glucosinolates act as the primary defence in these plants and the most recent suggestion is the ‘joint effects’ hypothesis, which states that both classes of chemical work together to benefit the plant and protect it from herbivores. This study investigates these hypotheses and utilized three experimental systems. The hyperaccumulator studied was Thlaspi caerulescens (Gange ecotype) which hyperaccumulates zinc. Plants were grown in a series of glasshouse experiments at a range of soil zinc amendments. There was a positive relationship between soil and foliar zinc; optimum growth occurred at 2000 mg Zn kg-1 soil and this equated to approximately 8000 mg Zn kg-1 shoot, although plants took up as much as 14000 mg Zn kg-1 shoot tissue at higher levels of soil amendment. The herbivore systems studied were generalist thrips (Franklinella occidentalis) and the specialist cabbage whitefly (Aleyrodes proletella). In addition, artificial damage caused by clipping served as a positive control. Four aromatic glucosinolates were extracted from T. caerulescens and two were identified as benzyl and p-OH-benzyl. Glucosinolates were synthesized 32 hours after damage occurred and reached a maximum concentration after 48 hours. Generally, lower concentrations of glucosinolates were observed in plants with higher foliar Zn concentrations and vice versa. However, when plants were subjected to a sustained and heavy herbivore attack, as was the case when thrips infested the plants, glucosinolate production occurred irrespective of foliar Zn concentration. This observation supports the ‘joint effects’ hypothesis, which states that both defences work in tandem and enhance overall defence. Nitrogen was an important component that directed herbivore response. Thrip feeding damage was negatively correlated with foliar nitrogen whilst cabbage whitefly (CWF) benefitted from higher N. Nitrogen was positively correlated with glucosinolate concentrations and glucosinolate content negatively affected the generalist thrips but not the specialist CWF. Data were analysed by accumulated general linear regression and the explanatory model for thrip feeding was C/N ratio + GS + Zn whilst the explanatory model for CWFs was C/N ratio + Zn. Use of the specialist feeder (CWF) allowed for study of the effects of zinc without glucosinolates confounding the results since the CWF was unaffected by foliar glucosinolates. Zinc acted as a defence against CWF but only at high concentrations. The data taken together show that zinc acts as a defence against herbivores that are unaffected by glucosinolates, but only at high concentrations. Zinc also defends the plant against generalist thrips, but glucosinolates are more influential in this case. This might be because of the severe and sustained damage that these plants suffered and systemic effects (i.e. higher concentrations of glucosinolates in undamaged leaves relative to attacked leaves) suggests flexibility in the Zn-glucosinolate relationship. The overall conclusion is in support of the joint effects hypothesis

The dynamics of leader technical competence, subordinate learning, and innovative work behaviors in high-tech, knowledge-based industry

This study tests a conceptual model for understanding the relationship between subordinates’ ‘learning work behaviour’ and ‘innovative work behaviour’, with the moderating role of their leaders’ self-reported as well as subordinates’ rated ‘leader technical competence’. The study was conducted in the context of a high-tech, knowledge-based telecommunications industry. Based on the evaluation of job description, leaders/managers with responsibilities of not only managing internal and external stakeholders but also capable to lead engineers to resolve any technical issue multiple-source data were collected from the identified leaders and their respective subordinates working with telecommunication operator (n¼179). This study proposed a three-way interaction moderation model between the independent variable (subordinate learning work behaviour) and the moderator variables (that is, the self-assessed leaders’ ‘technical competence’ and subordinates’ rated ‘leader’ technical competence’) to predict the subordinates’ ‘innovative work behaviour’. Our results demonstrate that that subordinate learning work behaviour had the strongest positive relationship with subordinate innovative work behaviour when both the leader self-assessment of technical competence and the subordinates rated leader’s technical competence were high. This study fills an important gap in leadership literature by focussing on the technical competence of leaders which has received little attention from leadership research in knowledge-based industries

Tri-Allelic Autosomal STR Patterns Observed in Pakistani Population during Forensic Case Work

The tri-allelic pattern is a genotyping abnormality that can be observed during routine short tandem repeat (STR) profiling in the field of forensic science. Fourteen tri-allelic patterns have been observed in nine different loci during routine forensic casework consisting of 20,000 STR profiles. All these 20,000 STR unrelated profiles were profiled using AmpFlSTR Identifiler Plus® and Global Filer® kits. Tri-allelic patterns can be divided into two types based on RFUs (relative fluorescent units) in peaks of three component alleles. Unequal RFUs of all three peaks are observed in the Type-I pattern, whereas in the Type-II pattern, RFUs of all three peaks are nearly equal. A total of nine novel tri-allelic genotypes were observed out of 20,000 unrelated individuals in the Pakistani population. All of these forensic cases belonged to the Type-I pattern which means that the sum of the height of two smaller peaks is nearly equal to the height of the third larger peak. The frequency of occurrence for all these patterns was compared with already reported data. In this study, eight novel tri-allelic patterns have been reported which are not listed in the National Institute of Standards and Technology (NIST) database as well as in any published article

A survey on sentiment analysis in Urdu: A resource-poor language

© 2020 Background/introduction: The dawn of the internet opened the doors to the easy and widespread sharing of information on subject matters such as products, services, events and political opinions. While the volume of studies conducted on sentiment analysis is rapidly expanding, these studies mostly address English language concerns. The primary goal of this study is to present state-of-art survey for identifying the progress and shortcomings saddling Urdu sentiment analysis and propose rectifications. Methods: We described the advancements made thus far in this area by categorising the studies along three dimensions, namely: text pre-processing lexical resources and sentiment classification. These pre-processing operations include word segmentation, text cleaning, spell checking and part-of-speech tagging. An evaluation of sophisticated lexical resources including corpuses and lexicons was carried out, and investigations were conducted on sentiment analysis constructs such as opinion words, modifiers, negations. Results and conclusions: Performance is reported for each of the reviewed study. Based on experimental results and proposals forwarded through this paper provides the groundwork for further studies on Urdu sentiment analysis

How moral efficacy and moral attentiveness moderate the effect of abusive supervision on moral courage?

Moral courage is a competency exercised in the workplace as employees face ethical challenges with a moral response. Managers exert considerable effort to foster subordinates’ moral courage given its positive organisational consequences. However abusive supervision, not uncommon in the organisational context, negatively affects moral courage. The purpose of this article is to examine the relationship between abusive supervision and moral courage as well as to test the moderating roles of moral efficacy and moral attentiveness on that very relationship. Data were collected from six public hospitals in Pakistan. The sample included 359 nurses and 121 nurse heads. The moderating roles were tested using the moderated hierarchical regression analysis. Results revealed that there was a significant negative relationship between abusive supervision and moral courage. In addition, this very relation was weaker when both moral efficacy and moral attentiveness were higher than when they were lower. The study provided new insights into the influence that abusive supervision might have on nurses’ moral courage and it also offered a practical assistance to employees in the health care industry and their leaders that moral efficacy and moral attentiveness would act as neutralisers in mitigating the pernicious effect of abusive supervision on nurses’ moral courage

Facial expression recognition using lightweight deep learning modeling

Facial expression is a type of communication and is useful in many areas of computer vision, including intelligent visual surveillance, human-robot interaction and human behavior analysis. A deep learning approach is presented to classify happy, sad, angry, fearful, contemptuous, surprised and disgusted expressions. Accurate detection and classification of human facial expression is a critical task in image processing due to the inconsistencies amid the complexity, including change in illumination, occlusion, noise and the over-fitting problem. A stacked sparse auto-encoder for facial expression recognition (SSAE-FER) is used for unsupervised pre-training and supervised fine-tuning. SSAE-FER automatically extracts features from input images, and the softmax classifier is used to classify the expressions. Our method achieved an accuracy of 92.50% on the JAFFE dataset and 99.30% on the CK+ dataset. SSAE-FER performs well compared to the other comparative methods in the same domain

Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed