Synergizing biotechnology and natural farming: pioneering agricultural sustainability through innovative interventions

The world has undergone a remarkable transformation from the era of famines to an age of global food production that caters to an exponentially growing population. This transformation has been made possible by significant agricultural revolutions, marked by the intensification of agriculture through the infusion of mechanical, industrial, and economic inputs. However, this rapid advancement in agriculture has also brought about the proliferation of agricultural inputs such as pesticides, fertilizers, and irrigation, which have given rise to long-term environmental crises. Over the past two decades, we have witnessed a concerning plateau in crop production, the loss of arable land, and dramatic shifts in climatic conditions. These challenges have underscored the urgent need to protect our global commons, particularly the environment, through a participatory approach that involves countries worldwide, regardless of their developmental status. To achieve the goal of sustainability in agriculture, it is imperative to adopt multidisciplinary approaches that integrate fields such as biology, engineering, chemistry, economics, and community development. One noteworthy initiative in this regard is Zero Budget Natural Farming, which highlights the significance of leveraging the synergistic effects of both plant and animal products to enhance crop establishment, build soil fertility, and promote the proliferation of beneficial microorganisms. The ultimate aim is to create self-sustainable agro-ecosystems. This review advocates for the incorporation of biotechnological tools in natural farming to expedite the dynamism of such systems in an eco-friendly manner. By harnessing the power of biotechnology, we can increase the productivity of agro-ecology and generate abundant supplies of food, feed, fiber, and nutraceuticals to meet the needs of our ever-expanding global population.

Efficacy, Immunogenicity, and Safety of a 9-Valent Human Papillomavirus Vaccine: Subgroup Analysis of Participants From Asian Countries

Background

A 9-valent human papillomavirus-6/11/16/18/31/33/45/52/58 (9vHPV) vaccine extends coverage to 5 next most common oncogenic types (31/33/45/52/58) in cervical cancer versus quadrivalent HPV (qHPV) vaccine. We describe efficacy, immunogenicity, and safety in Asian participants (India, Hong Kong, South Korea, Japan, Taiwan, and Thailand) from 2 international studies: a randomized, double-blinded, qHPV vaccine-controlled efficacy study (young women aged 16–26 years; NCT00543543; Study 001); and an immunogenicity study (girls and boys aged 9–15 years; NCT00943722; Study 002).

Methods

Participants (N = 2519) were vaccinated at day 1 and months 2 and 6. Gynecological samples (Study 001 only) and serum were collected for HPV DNA and antibody assessments, respectively. Injection-site and systemic adverse events (AEs) were monitored. Data were analyzed by country and vaccination group.

Results

9vHPV vaccine prevented HPV-31/33/45/52/58–related persistent infection with 90.4%–100% efficacy across included countries. At month 7, ≥97.9% of participants seroconverted for each HPV type. Injection-site AEs occurred in 77.7%–83.1% and 81.9%–87.5% of qHPV and 9vHPV vaccine recipients in Study 001, respectively, and 62.4%–85.7% of girls/boys in Study 002; most were mild to moderate.

Conclusions

The 9vHPV vaccine is efficacious, immunogenic, and well tolerated in Asian participants. Data support 9vHPV vaccination programs in Asia.

Clinical Trials Registration

NCT00543543; NCT00943722.

Clinical and economic impact of school-based nonavalent human papillomavirus vaccine on women in Singapore: a transmission dynamic mathematical model analysis

OBJECTIVE

To examine the epidemiological and economic impact of a nine-valent (nonavalent) human papillomavirus (HPV) 6/11/16/18/31/33/45/52/58 vaccine programme for young teenagers in Singapore.

DESIGN

Mathematical modelling.

SETTING

Pharmaco-economic simulation projection.

POPULATION

Singapore demography.

METHODS

Clinical, epidemiological and financial data from Singapore were used in a validated HPV transmission dynamic mathematical model to analyse the impact of nonavalent HPV vaccination over quadrivalent and bivalent vaccines in a school-based 2-dose vaccination for 11- to 12-year-old girls in the country. The model assumed routine cytology screening in the current rate (50%) and vaccine coverage rate of 80%.

MAIN OUTCOME MEASURES

Changes over a 100-year time period in the incidence and mortality rates of cervical cancer, case load of genital warts, and incremental cost-effectiveness ratio (ICER).

RESULTS

Compared with bivalent and quadrivalent HPV vaccination programmes, nonavalent HPV universal vaccination resulted in an additional reduction of HPV31/33/45/52/58 related CIN1 of 40.5%, CIN 2/3 of 35.4%, cervical cancer of 23.5%, and cervical cancer mortality of 20.2%. Compared with bivalent HPV vaccination, there was an additional reduction in HPV-6/11 related CIN1 of 75.7%, and genital warts of 78.9% in women and 73.4% in men. Over the 100 years, after applying a discount of 3%, disease management cost will be reduced by 32.5% (versus bivalent) and 7.5% (versus quadrivalent). The incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year gained was SGD 929 compared with bivalent vaccination and SGD 9864 compared with quadrivalent vaccination.

CONCLUSION

Universal two-dose nonavalent HPV vaccination for 11- to 12-year-old adolescent women is very cost-effective in Singapore.

TWEETABLE ABSTRACT

Nonavalent HPV vaccination of 11- to 12-year-old girls is cost-effective in Singapore.

Tricalcium phosphate solubilization and nitrogen fixation by newly isolated Aneurinibacillus aneurinilyticus CKMV1 from rhizosphere of Valeriana jatamansi and its growth promotional effect

Aneurinibacillus aneurinilyticus strain CKMV1 was isolated from rhizosphere of Valeriana jatamansi and possessed multiple plant growth promoting traits like production of phosphate solubilization (260 mg/L), nitrogen fixation (202.91 nmol ethylene mL⁻¹ h⁻¹), indole-3-acetic acid (IAA) (8.1 μg/mL), siderophores (61.60%), HCN (hydrogen cyanide) production and antifungal activity. We investigated the ability of isolate CKMV1 to solubilize insoluble P via mechanism of organic acid production. High-performance liquid chromatography (HPLC) study showed that isolate CKMV1 produced mainly gluconic (1.34%) and oxalic acids. However, genetic evidences for nitrogen fixation and phosphate solubilization by organic acid production have been reported first time for A. aneurinilyticus strain CKMV1. A unique combination of glucose dehydrogenase (gdh) gene and pyrroloquinoline quinone synthase (pqq) gene, a cofactor of gdh involved in phosphate solubilization has been elucidated. Nitrogenase (nif H) gene for nitrogen fixation was reported from A. aneurinilyticus. It was notable that isolate CKMV1 exhibited highest antifungal against Sclerotium rolfsii (93.58%) followed by Fusarium oxysporum (64.3%), Dematophora necatrix (52.71%), Rhizoctonia solani (91.58%), Alternaria sp. (71.08%) and Phytophthora sp. (71.37%). Remarkable increase was observed in seed germination (27.07%), shoot length (42.33%), root length (52.6%), shoot dry weight (62.01%) and root dry weight (45.7%) along with NPK (0.74, 0.36, 1.82%) content of tomato under net house condition. Isolate CKMV1 possessed traits related to plant growth promotion, therefore, could be a potential candidate for the development of biofertiliser or biocontrol agent and this is the first study to include the Aneurinibacillus as PGPR.

Immobilization of Bacillus amyloliquefaciens SP1 and its alkaline protease in various matrices for effective hydrolysis of casein

An extracellular alkaline protease producing B. amyloliquefaciens SP1 was isolated from apple rhizosphere having multifarious plant growth-promoting activities. B. amyloliquefaciens SP1 protease was immobilized using various concentrations of calcium alginate, agar and polyacrylamide to determine the optimum concentration for formation of the beads. Enzyme activity before immobilization (at 60 °C, pH 8.0 for 5 min) was 3580 µg/ml/min. The results of immobilization with various matrices revealed that 3 % calcium alginate (2829.92 µg/ml/min), 2 % agar (2600 µg/ml/min) and 10 % polyacrylamide (5698.99 µg/ml/min) were optimum concentrations for stable bead formation. Immobilized enzyme reusability results indicated that calcium alginate, agar and polyacrylamide beads retained 25.63, 22.05 and 34.04 % activity in their fifth repeated cycle, respectively. In cell immobilization technique, the free movement of microorganisms is restricted in the process, and a semi-continuous system of fermentation can be used. In the present work, this technique has been used for alkaline protease production using different matrices. Polyacrylamide (10 %) was found with the highest total alkaline protease titer, i.e., 24,847 µg/ml/min semi-continuously for 18 days as compared to agar (total enzyme titer: 5800 in 10 days) and calcium alginate (total enzyme titer: 13,010 in 15 days). This present study reported that polyacrylamide (10 %) among different matrices has maximum potential of immobilization of B. amyloliquefaciens SP1 and its detergent stable alkaline protease with effective application in bloodstain removal.

Molecular characterization of alkaline protease of Bacillus amyloliquefaciens SP1 involved in biocontrol of Fusarium oxysporum

An alkaline protease gene was amplified from genomic DNA of Bacillus amyloliquefaciens SP1 which was involved in effective biocontrol of Fusarium oxysporum. We investigated the antagonistic capacity of protease of B. amyloliquifaciens SP1, under in vitro conditions. The 5.62 fold purified enzyme with specific activity of 607.69U/mg reported 24.14% growth inhibition of F. oxysporum. However, no antagonistic activity was found after addition of protease inhibitor i.e. PMSF (15mM) to purified enzyme. An 1149bp nucleotide sequence of protease gene encoded 382 amino acids of 43kDa and calculated isoelectric point of 9.29. Analysis of deduced amino acid sequence revealed high homology (86%) with subtilisin E of Bacillus subtilis. The B. amyloliquefaciens SP1 protease gene was expressed in Escherichiax coli BL21. The expressed protease was secreted into culture medium by E. coli and exhibited optimum activity at pH8.0 and 60°C. The most reliable three dimensional structure of alkaline protease was determined using Phyre 2 server which was validated on the basis of Ramachandran plot and ERRAT value. The expression and structure prediction of the enzyme offers potential value for commercial application in agriculture and industry.

No effect of femoral offset on bone implant micromotion in an experimental model

BACKGROUND

In total hip replacement (THR), the femoral offset (FO) is assessed preoperatively, and the surgeon must determine whether to restore, increase, or decrease the FO based on experience and the patient's clinical history. The FO is known to influence the abductor muscle strength, range of motion (ROM), gait, and hip pain after THR; however, the true effect of FO on bone implant micromotion is unclear. Therefore, we investigated to assess: (1) the muscle loading response during gait, (2) whether FO affects bone implant micromotion during gait.

HYPOTHESIS

A variation of ±10mm from the anatomical FO affects the muscle loading forces.

MATERIALS AND METHODS

We modified a personalized musculoskeletal model of the lower extremity to determine the 3-dimensional contact forces at the hip joint in the presence of a stem with varying offsets during a gait cycle. A detailed finite element (FE) model was then constructed for increased, restored, and decreased FOs. The maximum load obtained during normal walking gait from the musculoskeletal model was applied to the respective FE models, and the resultant stem-bone micromotion and stress distribution were computed.

RESULTS

Increasing the FO to +10mm decreased the peak force generated by the abductor muscles during the cycle by 15.0% and decreasing the FO to -10mm increased the von Mises stress distribution at the distal bone by 77.5% (P<0.05). A variation of the offset within 10mm of the anatomical offset showed no significant differences in micromotion (P>0.05) and peak stresses (P>0.05).

DISCUSSION

Coupling the musculoskeletal model of the gait cycle with FE analysis provides a realistic model to understand how FO affects bone implant micromotion. We found that there was no effect of FO on bone implant micromotion; thus, a surgeon does not need to evaluate the implications of FO on micromotion and can determine a FO that best decreases the work load of abductor muscles, increases ROM, and reduces hip pain.

LEVEL OF EVIDENCE

IV, biomechanical study.

Over, but not out-recognition and preventing aircraft-assisted murder-suicide by Aircrew

Context and introduction

The recent crash of Germanwings Flight 4U9525 appears to be the latest act of aircraft-assisted murder-suicide. The psychiatric preventive aspects of the murder-suicide need to be discussed, and effective measures for recognition and prevention of this murder-suicide are needed. Aircrew health is biased towards the physical ailments, and evaluation manuals have not discussed the mental health aspects, especially preventive strategies. These strategies involve multifactorial interventions, their applicability and usefulness are not globally validated.

Objectives and methods

Thanatology has since long, focused on early detection of mental distress and elucidating behavioural and psychological factors that predispose towards attempts at self-harm. Aircrew forms a different group from the general population. The recognition and preventive strategies in this special group, must, therefore, be tailored to this group with its special characteristics.

Data sources, study selection and data synthesis publications were identified via electronic searches using multiple search terms related to suicide prevention. The available effective preventive measures were juxtaposed on the current concepts in aerospace psychiatry.

Conclusions

Murder-suicide by aircrew is an event that is the culmination of undetected, ignored or even condoned discrete events that gradually progress and insidiously escalate. The importance of psychological factors in this catastrophic event needs to be disseminated amongst psychiatrists, and aircrew medical examiners. Ascertaining which components of suicide prevention programmes are effective in early recognition of aircrew who may attempt or complete the murder-suicide and putting into practice these to optimize the use of limited resources, is therefore essential and necessary.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Improvement for enhanced xylanase production by Cellulosimicrobium cellulans CKMX1 using central composite design of response surface methodology

The effects of yeast extract (X₁), NH₄NO₃ (X₂), peptone (X₃), urea (X₄), CMC (X₅), Tween 20 (X₆), MgSO₄ (X₇), and CaCO₃ (X₈) on production of xylanase from Cellulosimicrobium cellulans CKMX1 were optimized by statistical analysis using response surface methodology (RSM). The RSM was used to optimize xylanase production by implementing the Central composite design. Statistical analysis of the results showed that the linear, interaction and quadric terms of these variables had significant effects. However, only the linear effect of X₄, X₅, interaction effect of X₁X₇, X₁X₈, X₂X₃, X₂X₈, X₃X₆, X₃X₈, X₄X₆, X₄X₇, X₅X₇, X₅X₈ and quadratic effect of X ₃² , X ₅² and X ₇² found to be insignificant terms in the quadratic model and had no response at significant level. The minimum and maximum xylanase production obtained was 331.50 U/g DBP and 1027.65 U/g DBP, respectively. The highest xylanase activity was obtained from Run No. 30, which consisted of yeast extract (X₁), 1.00 g (%); NH₄NO₃ (X₂), 0.20 g (%); peptone (X₃), 1.00 g (%); urea (X₄), 10 mg (%); CMC (X₅), 1.00 g (%); Tween 20 (X₆), 0.02 mL (%); CaCO₃ (X₇), 0.50 g (%) and MgSO₄ (X₈), 9.0 g (%). The optimization resulted in 3.1-fold increase of xylanase production, compared with the lowest xylanase production of 331.50 U/g DBP after 72 h of incubation in stationary flask experiment. Application of cellulase-free xylanase in pulp biobleaching from C. cellulans CKMX1 under C-E_P-D sequence has been shown to bring about a 12.5 % reduction of chlorine, decrease of 0.8 kappa points (40 %), and gain in brightness was 1.42 % ISO points in 0.5 % enzyme treated pulp as compared to control.

Purification and characterization of detergent stable alkaline protease from Bacillus amyloliquefaciens SP1 isolated from apple rhizosphere

A thermostable extracellular alkaline protease producing Bacillus amyloliquefaciens SP1 was isolated from apple rhizosphere having multifarious plant growth promoting activities. Strain SP1 was purified to 6.48-fold using four-step purification protocol and characterized in detail for its robustness and ecofriendly application in leather and detergent industries. Structural analysis revealed that the protease was monomeric and had a molecular weight of 43 kDa. It exhibited optimum activity at 60°C in alkaline environment (pH 8.0) and stable in the presence of surfactants and oxidizing agents. Enzyme was thermostable at 50°C and retained more than 70% activity after 30 min incubation. It has shown stain removal property and dehairing of goat skin without chemical assistance and hydrolyzing fibrous proteins. This protease showed Km of 0.125 mg ml(-1) and V(max) of 12820 μg ml(-1) indicating its excellent affinity and catalytic role. Thermal inactivation of the pure enzyme followed first-order kinetics. The half life of the pure enzyme at 50, 60, and 65°C was 77, 19.80, and 13.33 min, respectively. The activation energy was 37.19 KJ mol(-1). The results suggest that the B. amyloliquefaciens SP1 has a potential application in different industries.

Modification in the properties of paper by using cellulase-free xylanase produced from alkalophilic Cellulosimicrobium cellulans CKMX1 in biobleaching of wheat straw pulp

Alkalophilic Cellulosimicrobium cellulans CKMX1 isolated from mushroom compost is an actinomycete that produces industrially important and environmentally safer thermostable cellulase-free xylanase, which is used in the pulp and paper industry as an alternative to the use of toxic chlorinated compounds. Strain CKMX1 was previously characterized by metabolic fingerprinting, whole-cell fatty acids methyl ester analysis, and 16S rDNA and was found to be C. cellulans CKMX1. Crude enzyme (1027.65 U/g DBP) produced by C. cellulans CKMX1, having pH and temperature optima of 8.0 and 60 °C, respectively, in solid state fermentation of apple pomace, was used in the production of bleached wheat straw pulp. Pretreatment with xylanase at a dose of 5 U/g after pulping decreased pulp kappa points by 1.4 as compared with the control. Prebleaching with a xylanase dose of 5 U/g pulp reduced the chlorine charge by 12.5%, increased the final brightness points by approximately 1.42% ISO, and improved the pulp strength properties. Xylanase could be substituted for alkali extraction in C–Ep–D sequence and used for treating chemically bleached pulp, resulting in bleached pulp with higher strength properties. Modification of bleached pulp with 5 U of enzyme/g increased pulp whiteness and breaking length by 1.03% and 60 m, respectively; decreased tear factor of pulp by 7.29%; increased bulk weight by 3.99%, as compared with the original pulp. Reducing sugars and UV-absorbing lignin-derived compound values were considerably higher in xylanase-treated samples. Cellulosimicrobium cellulans CKMX1 has a potential application in the pulp and paper industries.

Purification and characterization of cellulase-free low molecular weight endo β-1,4 xylanase from an alkalophilic Cellulosimicrobium cellulans CKMX1 isolated from mushroom compost

Alkalophilic Cellulosimicrobium cellulans CKMX1 isolated from mushroom compost is first report on actinomycetes that has the ability to produce thermostable cellulase-free xylanase, which is an important industrial enzyme used in the pulp and paper industry. Strain CKMX1 was characterized by metabolic fingerprinting, whole-cell fatty acids methyl ester analysis and 16Sr DNA and found to be C. cellulans CKMX1.The enzyme was purified by gel permeation and anion exchange chromatography and had a molecular mass of 29 kDa. Xylanase activity was optimum at pH 8.0 and 55 °C. The enzyme was somewhat thermostable, retaining 50 % of the original activity after incubation at 50 °C for 30 min. The xylanase had K m and V max values of 2.64 mg/ml and 2,000 µmol/min/mg protein in oat spelt xylan, respectively. All metal ions except HgCl2, CoCl2 as well as CdCl2 were well tolerated and did not adversely affect xylanase activity. The deduced internal amino acid sequence of C. cellulans CKMX1 xylanase by matrix assisted laser desorption ionization-time of flight mass spectrometry resembled the sequence of β-1,4-endoxylanase, which is a member of glycoside hydrolase family 11. Some of the novel characteristics that make this enzyme potentially effective in xylan biodegradation could be useful for pulp and paper biobleaching are discussed in this manuscript.

Intraoperative fluid and pharmacologic management and the anesthesiologist's supervisory role for nontraditional technologies during liver transplantation: a survey of US academic centers

BACKGROUND

Volume resuscitation and use of vasoactive medications during liver transplantation has not been systematically assessed. Furthermore, the anesthesiologist's role for intraoperative oversight of technologies such as renal replacement therapy and procedures such as venovenous bypass is poorly defined, and it is unclear if the center's annual transplant frequency affects these practices.

METHODS

We conducted a database analysis of the Liver Transplant Anesthesia Consortium survey 202 that addresses these questions. Data from US academic liver transplant anesthesia programs meeting inclusion criteria were included. Results were categorized by their annual transplant volume.

RESULTS

A representative sample of 66% of all eligible centers contributed to the results. Normal saline among crystalloids and albumin among colloids were the most frequently chosen maintenance and non-blood product volume expansion fluids, with little variation by center size. A large variety of vasoactive agents is routinely utilized across programs, with vasopressors as a cornerstone of hemodynamic support. Large programs seem to use less of these agents compared with lower volume centers.

CONCLUSION

Anesthesiologists are increasingly involved in oversight and management of intraoperative renal replacement therapies, venovenous bypass and cell saver devices with rising transplant frequency. This new insight may be indicative of skill sets needed by members of liver transplantation anesthesia teams and should be considered in curriculum design for hepatobiliary transplant anesthesia fellowships.

Liver transplantation outcome in patients with angiographically proven coronary artery disease: a multi-institutional study

Over the last decade the age of liver transplant (LT) recipients and the likelihood of coronary artery disease (CAD) in this population have increased. There are no multicenter studies that have examined the impact of CAD on LT outcomes. In this historical cohort study, we identified adult LT recipients who underwent angiography prior to transplantation at seven institutions over a 12-year period. For each patient we recorded demographic data, recipient and donor risk factors, duration of follow-up, the presence of angiographically proven obstructive CAD (≥50% stenosis) and post-LT survival. Obstructive CAD was present in 151 of 630 patients, the CAD(+) group. Nonobstructive CAD was found in 479 patients, the CAD(-) group. Patient survival was similar for the CAD(+) group (adjusted HR 1.13, CI = [0.79, 1.62], p = 0.493) compared to the CAD(-) group. The CAD(+) patients were further stratified into severe (CADsev, >70% stenosis, n = 96), and moderate CAD (CADmod, 50-70% stenosis, n = 55) groups. Survival for the CADsev (adjusted HR = 1.26, CI = [0.83, 1.91], p = 0.277) and CADmod (adjusted HR = 0.93, CI = [0.52, 1.66], p = 0.797) groups were similar to the CAD(-) group. We conclude that when current CAD treatment strategies are employed prior to transplant, post-LT survival is not significantly different between patients with and without obstructive CAD.

Beneficial effects of Rhizopus oligosporus fermentation on reduction of glucosinolates, fibre and phytic acid in rapeseed (Brassica napus) meal

Solid state fermentation was employed using Rhizopus oligosporus to develop a fermented product from rapeseed meal (RSM). The contents of glucosinolates, thiooxazolidones, phytic acid and crude fibre declined by 43.1%, 34%, 42.4% and 25.5%, respectively, following inoculation with R. oligosporus. Fermentation also increased nitrogen and protein contents of the meal. This study may open a new prospective for a simple and cost effective technique for reduction of toxicants in RSM.

Pathology of fatal perioperative myocardial infarction: implications regarding pathophysiology and prevention

The aim of this study was to determine the pathology of fatal postoperative myocardial infarction (MI) and compare it with that of non-operative myocardial infarction. Histopathological analyses of coronary arteries and myocardium were performed on autopsy heart specimens (n = 67), and clinical attributes were studied. Findings of perioperative MI (n = 42) were compared to those of non-perioperative MI (n = 25). Significant atherosclerotic obstruction (> 50% cross-sectional narrowing) was observed in the majority of patients (93%). Left main (> 50% cross-sectional narrowing) and/or three-vessel coronary artery disease were especially common (44%) in this group. Evidence of unstable plaques with disruption was noted in 55% of perioperative MI patients (n = 23); plaque hemorrhage was found in 45% (n = 19). Predicting the site of infarction based on severity of underlying stenosis would have been unsuccessful in more than half the patients in both perioperative and nonoperative MI groups. Clinical profiles of the patients in the two groups were similar in terms of prior cardiac history, gender and age. Fatal perioperative MI occurs predominantly in patients with multivessel coronary disease, especially left main and three-vessel disease. The severity of preexisting underlying stenosis did not predict the resulting infarct territory. Evidence of acute plaque disruption in the infarct-related artery is common. Perioperative MIs have similar coronary artery pathology to non-operative MIs with regard to coronary plaque hemorrhage, rupture, and thrombus formation and probably occur by a similar mechanism.

Transition Metal Complexes of [2-{Di(m-tolyl)phosphino}ethyl]diphenylphosphine

The 1 : 1 complexes of chelating diphosphine, [2-{di(m-tolyl)phosphino}ethyl]diphenylphosphine (pmtpf), with nickel(II), palladium(II) and platinum(II) halides and thiocyanates and 2 : 1 complexes with nickel(II) perchlorates have been prepared. Ligand (pmtpf) forms low-spin square-planar and diamagnetic [M(pmtpf)X2](where X = Cl, Br, I or NCS; M = Ni, Pd or Pt) and [Ni(pmtpf)2]- (ClO4)2 complexes. Complexes of metal carbonyls having the general formula [(pmtpf)M(CO)4] (where M = Cr, Mo or W) have also been synthesized. These complexes have been characterized on the basis of element analysis, electronic, infrared and 1H N.M.R. spectral measurements, magnetic susceptibilities and electrical conductance data. In all cases studied this ligand acts as a chelating ditertiary phosphine.