Our shared global responsibility: Safeguarding crop diversity for future generations

The resilience and sustainability of food systems depend on crop diversity. It is used by breeders to produce new and better varieties, and by farmers to respond to new challenges or demands and to spread risk. However, crop diversity can only be used if it has been conserved, can be identified as the solution for a given problem, and is available. As the ways in which crop diversity is used in research and breeding change and expand, the global conservation system for crop diversity must keep pace; it must provide not only the biological materials themselves, but also the relevant information presented in a comprehensive and coherent way—all while ensuring equitable access and benefit sharing. Here we explore the evolving priorities for global efforts to safeguard and make available the diversity of the world's crops through ex situ genetic resource collections. We suggest that collections held by academic institutions and other holders that are not standard gene banks should be better integrated in global efforts and decision-making to conserve genetic resources. We conclude with key actions that we suggest should be taken to ensure that crop diversity collections of all types are able to fulfill their role to foster more diverse, equitable, resilient, and sustainable food systems globally.

Adapting Agriculture to Climate Change: A Synopsis of Coordinated National Crop Wild Relative Seed Collecting Programs across Five Continents

The Adapting Agriculture to Climate Change Project set out to improve the diversity, quantity, and accessibility of germplasm collections of crop wild relatives (CWR). Between 2013 and 2018, partners in 25 countries, heirs to the globetrotting legacy of Nikolai Vavilov, undertook seed collecting expeditions targeting CWR of 28 crops of global significance for agriculture. Here, we describe the implementation of the 25 national collecting programs and present the key results. A total of 4587 unique seed samples from at least 355 CWR taxa were collected, conserved ex situ, safety duplicated in national and international genebanks, and made available through the Multilateral System (MLS) of the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant Treaty). Collections of CWR were made for all 28 targeted crops. Potato and eggplant were the most collected genepools, although the greatest number of primary genepool collections were made for rice. Overall, alfalfa, Bambara groundnut, grass pea and wheat were the genepools for which targets were best achieved. Several of the newly collected samples have already been used in pre-breeding programs to adapt crops to future challenges.

State of ex situ conservation of landrace groups of 25 major crops

Crop landraces have unique local agroecological and societal functions and offer important genetic resources for plant breeding. Recognition of the value of landrace diversity and concern about its erosion on farms have led to sustained efforts to establish ex situ collections worldwide. The degree to which these efforts have succeeded in conserving landraces has not been comprehensively assessed. Here we modelled the potential distributions of eco-geographically distinguishable groups of landraces of 25 cereal, pulse and starchy root/tuber/fruit crops within their geographic regions of diversity. We then analysed the extent to which these landrace groups are represented in genebank collections, using geographic and ecological coverage metrics as a proxy for genetic diversity. We find that ex situ conservation of landrace groups is currently moderately comprehensive on average, with substantial variation among crops; a mean of 63% ± 12.6% of distributions is currently represented in genebanks. Breadfruit, bananas and plantains, lentils, common beans, chickpeas, barley and bread wheat landrace groups are among the most fully represented, whereas the largest conservation gaps persist for pearl millet, yams, finger millet, groundnut, potatoes and peas. Geographic regions prioritized for further collection of landrace groups for ex situ conservation include South Asia, the Mediterranean and West Asia, Mesoamerica, sub-Saharan Africa, the Andean mountains of South America and Central to East Asia. With further progress to fill these gaps, a high degree of representation of landrace group diversity in genebanks is feasible globally, thus fulfilling international targets for their ex situ conservation.

Crop genetic erosion: understanding and responding to loss of crop diversity

Crop diversity underpins the productivity, resilience and adaptive capacity of agriculture. Loss of this diversity, termed crop genetic erosion, is therefore concerning. While alarms regarding evident declines in crop diversity have been raised for over a century, the magnitude, trajectory, drivers and significance of these losses remain insufficiently understood. We outline the various definitions, measurements, scales and sources of information on crop genetic erosion. We then provide a synthesis of evidence regarding changes in the diversity of traditional crop landraces on farms, modern crop cultivars in agriculture, crop wild relatives in their natural habitats and crop genetic resources held in conservation repositories. This evidence indicates that marked losses, but also maintenance and increases in diversity, have occurred in all these contexts, the extent depending on species, taxonomic and geographic scale, and region, as well as analytical approach. We discuss steps needed to further advance knowledge around the agricultural and societal significance, as well as conservation implications, of crop genetic erosion. Finally, we propose actions to mitigate, stem and reverse further losses of crop diversity.

A Methodological Approach for Prioritization and Rationalization of Field Genebank Accessions of Coffee Genetic Resources: A Case Study of CATIE International Coffee Collection, Costa Rica

Good management of coffee collections is important because they ensure long-term availability of germplasm to guarantee the sustainability of coffee value chain. The conservation of coffee genetic resources is essential to provide the raw materials for breeding and improvement of the crop. Many genetic resources of wild arabica coffee have been collected in the second half of the 20th century by several international collecting missions, including by Food and Agriculture Organization of the United Nations, ORSTOM (now IRD), Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), and IPGRI (now Bioversity International), and are conserved in several national genebanks and at the CATIE International Coffee Collection (CICC) in Turrialba, Costa Rica. Over the past decades, many of the original accessions of the CICC have become threatened due to age, pests and diseases, inadequate management, and waterlogging. There is thus an urgent need to rejuvenate and rationalize the collection to ensure the long-term maintenance of the genetic diversity of the original accessions. Here we present the methodological approach we followed to carry out an in-depth assessment of the status of the coffee collection at CATIE and to prioritize accession-specific actions for the rationalization of the collection. This can be used as a model for other collections to assess and rationalize their own field genebank, with a view to improving their management in the most cost-effective way. The study identified many discrepancies between the number of accessions in the field and genebank records and revealed that 80 accessions have been lost from the collection since 2014 and that approximately 80% of the accessions were threatened and in need of intervention. Furthermore, the in-depth study identified the most diverse and valued accessions for the rationalization of the CICC field genebank and those that are in urgent need of safety duplication.

Envisaging an Effective Global Long-Term Agrobiodiversity Conservation System That Promotes and Facilitates Use

Genebanks were established out of a recognised need not just to provide genetic variation to support breeding objectives but to prevent crop diversity from being lost entirely for future users. Such conservation objectives may have led, over the past few decades, to a gradually diminishing connection between genebanks and current users of diversity. While there continues to be large-scale distribution of germplasm from genebanks to recipients worldwide, relatively little is known or published about the detailed trends in the demand for genebank materials. Meanwhile, the rapid expansion of the applications and uses of modern genomic technologies and approaches is, undoubtedly, having a transformational impact on breeding, research and the demand for certain genetic resources and associated data. These trends will require genebanks to be responsive and to adapt. They also provide important opportunities for genebanks to reorganize and become more efficient individually and as a community. Ultimately, future challenges and opportunities are likely to drive more demand for genetic diversity and provide an important basis for genebanks to gear up.

Biocultural Diversity for Food System Transformation Under Global Environmental Change

Biocultural diversity is central to the nutrition, resilience, and adaptive capacity of Indigenous and traditional peoples, who collectively maintain the longest ongoing human experiences with the provision of food under environmental change. In the form of crops and livestock and associated knowledge on their cultivation and use, food-related biocultural diversity likewise underpins global food security. As food system transformation is increasingly recognized as an urgent priority, we argue that food security, sustainability, resilience, and adaptive capacity can be furthered through greater emphasis on conservation, use, and celebration of food-related biocultural diversity. We provide examples from the Parque de la Papa, Peru, a “food biocultural diversity neighborhood” which through advocacy and partnerships based around its diversity, has both enhanced local communities and contributed to food security at a much larger scale. We outline collaborative actions which we believe are important to up- and out-scale food biocultural diversity neighborhood successes. Further research and knowledge sharing are critical to better document, understand, track, and communicate the value, functions, and state of biocultural diversity in food systems. Expanded training and capacity development opportunities are important to enable the interchange of experiences and visions on food, health, sustainability and resilience, climate adaptation, equity and justice, and livelihood generation with others facing similar challenges. Finally, strengthened networking across food biocultural diversity neighborhoods is essential to their persistence and growth as they increasingly engage with local, national, and international organizations, based on shared interests and on their own terms, across five continents.

Germplasm Acquisition and Distribution by CGIAR Genebanks

The international collections of plant genetic resources for food and agriculture (PGRFA) hosted by 11 CGIAR Centers are important components of the United Nations Food and Agriculture Organization's global system of conservation and use of PGRFA. They also play an important supportive role in realizing Target 2.5 of the Sustainable Development Goals. This paper analyzes CGIAR genebanks' trends in acquiring and distributing PGRFA over the last 35 years, with a particular focus on the last decade. The paper highlights a number of factors influencing the Centers' acquisition of new PGRFA to include in the international collections, including increased capacity to analyze gaps in those collections and precisely target new collecting missions, availability of financial resources, and the state of international and national access and benefit-sharing laws and phytosanitary regulations. Factors contributing to Centers' distributions of PGRFA included the extent of accession-level information, users' capacity to identify the materials they want, and policies. The genebanks' rates of both acquisition and distribution increased over the last decade. The paper ends on a cautionary note concerning the potential of unresolved tensions regarding access and benefit sharing and digital genomic sequence information to undermine international cooperation to conserve and use PGRFA.

Modeling of crop wild relative species identifies areas globally for in situ conservation

The impact of climate change is causing challenges for the agricultural production and food systems. More nutritious and climate resilient crop varieties are required, but lack of available and accessible trait diversity is limiting crop improvement. Crop wild relatives (CWR) are the wild cousins of cultivated crops and a vast resource of genetic diversity for breeding new, higher yielding, climate change tolerant crop varieties, but they are under-conserved (particularly in situ), largely unavailable and therefore underutilized. Here we apply species distribution modelling, climate change projections and geographic analyses to 1261 CWR species from 167 major crop genepools to explore key geographical areas for CWR in situ conservation worldwide. We identify 150 sites where 65.7% of the CWR species identified can be conserved for future use.

Serum uric acid is not independently associated with plasma renin activity and plasma aldosterone in hypertensive adults

BACKGROUND AND AIMS

In experimental investigations conducted in rats, raising serum uric acid (SUA) levels resulted in the stimulation of intrarenal renin expression. Studies in humans exploring the association of SUA with plasma renin activity (PRA) yielded conflicting results. Moreover, little is known about the relationship of SUA with plasma aldosterone concentration (PAC). The study aimed to assess the relationship between SUA levels, PRA, and PAC and the influence of age, gender, body mass index (BMI), and hyperuricemia on these relationships in subjects with essential hypertension (EH).

METHODS AND RESULTS

We enrolled 372 hypertensive patients (mean age 45 ± 12 years, men 67%) with uncomplicated EH that was not pharmacologically treated. The study population was divided in tertiles according to SUA levels. While PRA did not differ significantly across the three tertiles, PAC was higher in subjects belonging to the uppermost tertile of SUA than those in the lower ones (p = 0.0429); however, this difference lost statistical significance after adjustment for age, sex, BMI, and serum creatinine. Univariate correlation analyses showed significant associations of SUA with PRA (r = 0.137; p = 0.008) and PAC (r = 0.179; p < 0.001). However, these relationships were not significant after correcting for confounding factors in multiple linear regression analyses. We did not observe statistically significant effect modification by gender, age, BMI, and hyperuricemia.

CONCLUSION

SUA levels are weakly associated with PRA and PAC in adults with untreated EH. These relationships were lost after adjustment for age, sex, BMI, and serum creatinine.

Diversity for Food Security: Improving Human Nutrition through Better Evaluation, Management, and use of Plant Genetic Resources

The use of plant genetic diversity is essential for ensuring an adequate and stable supply of diverse food crops as well as for enhancing their nutritional quality. The role of effective conservation, management, and use of plant genetic resources in ensuring the availability of a diverse range of nutritious food crops is recognized throughout the work of the International Plant Genetic Resources Institute (IPGRI). Several research activities in the Institute's programme highlight how the diversity between and within food crop species is inextricably linked to the diversity of human cultural needs, preferences, and knowledge systems with respect to the management and use of plant genetic resources. The nutritional quality of food crops is among the major considerations that are important in both the improvement and conservation of genetic resources. Specific examples from IPGRI's work are used to illustrate these linkages.

Origins of food crops connect countries worldwide

Research into the origins of food plants has led to the recognition that specific geographical regions around the world have been of particular importance to the development of agricultural crops. Yet the relative contributions of these different regions in the context of current food systems have not been quantified. Here we determine the origins (‘primary regions of diversity’) of the crops comprising the food supplies and agricultural production of countries worldwide. We estimate the degree to which countries use crops from regions of diversity other than their own (‘foreign crops’), and quantify changes in this usage over the past 50 years. Countries are highly interconnected with regard to primary regions of diversity of the crops they cultivate and/or consume. Foreign crops are extensively used in food supplies (68.7% of national food supplies as a global mean are derived from foreign crops) and production systems (69.3% of crops grown are foreign). Foreign crop usage has increased significantly over the past 50 years, including in countries with high indigenous crop diversity. The results provide a novel perspective on the ongoing globalization of food systems worldwide, and bolster evidence for the importance of international collaboration on genetic resource conservation and exchange.

Global conservation priorities for crop wild relatives

The wild relatives of domesticated crops possess genetic diversity useful for developing more productive, nutritious and resilient crop varieties. However, their conservation status and availability for utilization are a concern, and have not been quantified globally. Here, we model the global distribution of 1,076 taxa related to 81 crops, using occurrence information collected from biodiversity, herbarium and gene bank databases. We compare the potential geographic and ecological diversity encompassed in these distributions with that currently accessible in gene banks, as a means to estimate the comprehensiveness of the conservation of genetic diversity. Our results indicate that the diversity of crop wild relatives is poorly represented in gene banks. For 313 (29.1% of total) taxa associated with 63 crops, no germplasm accessions exist, and a further 257 (23.9%) are represented by fewer than ten accessions. Over 70% of taxa are identified as high priority for further collecting in order to improve their representation in gene banks, and over 95% are insufficiently represented in regard to the full range of geographic and ecological variation in their native distributions. The most critical collecting gaps occur in the Mediterranean and the Near East, western and southern Europe, Southeast and East Asia, and South America. We conclude that a systematic effort is needed to improve the conservation and availability of crop wild relatives for use in plant breeding.

Relationships between mild hyperuricaemia and aortic stiffness in untreated hypertensive patients

BACKGROUND AND AIMS

Clinical studies exploring the relationship between serum uric acid (SUA) and arterial stiffness yielded conflicting results. Only in a few of these studies, arterial distensibility was examined by measuring aortic pulse wave velocity (PWV), which is considered the gold standard for evaluating arterial stiffness. In none of the previous investigations was the influence of SUA on aortic distensibility assessed, taking into account the effect of albuminuria. The purpose of our study was to comprehensively analyse the relationships between SUA and aortic PWV in a group of essential hypertensive patients.

METHODS AND RESULTS

We enrolled 222 untreated and uncomplicated hypertensive subjects (mean age: 44 ± 10 years; 60% males), without gout. In all patients, SUA and urinary albumin excretion rate (AER) were determined. Moreover, carotid-femoral (c-f) PWV was measured. C-f PWV was significantly higher in hypertensive patients belonging to the uppermost tertile of SUA distribution, compared to subjects of the lowest tertiles (10.9 ± 2.2 vs. 10 ± 1.8 vs. 9.9 ± 1.7 m s(-1); p = 0.001). In univariate analysis, SUA correlated with c-f PWV (r = 0.24; p < 0.001). This association disappeared when AER was added in a multiple regression model, including SUA, age, mean arterial pressure, gender, metabolic syndrome components and glomerular filtration rate.

CONCLUSION

The results of our study showed that, in essential hypertensive subjects, there is a positive relationship between mild hyperuricaemia and aortic stiffness. This association weakened after adjustment for covariates and lost statistical significance after further correction for albuminuria.

Relationships between mild hyperuricaemia and aortic stiffness in untreated hypertensive patients

BACKGROUND AND AIMS

Clinical studies exploring the relationship between serum uric acid (SUA) and arterial stiffness yielded conflicting results. Only in a few of these studies, arterial distensibility was examined by measuring aortic pulse wave velocity (PWV), which is considered the gold standard for evaluating arterial stiffness. In none of the previous investigations was the influence of SUA on aortic distensibility assessed, taking into account the effect of albuminuria. The purpose of our study was to comprehensively analyse the relationships between SUA and aortic PWV in a group of essential hypertensive patients.

METHODS AND RESULTS

We enrolled 222 untreated and uncomplicated hypertensive subjects (mean age: 44 ± 10 years; 60% males), without gout. In all patients, SUA and urinary albumin excretion rate (AER) were determined. Moreover, carotid-femoral (c-f) PWV was measured. C-f PWV was significantly higher in hypertensive patients belonging to the uppermost tertile of SUA distribution, compared to subjects of the lowest tertiles (10.9 ± 2.2 vs. 10 ± 1.8 vs. 9.9 ± 1.7 m s(-1); p = 0.001). In univariate analysis, SUA correlated with c-f PWV (r = 0.24; p < 0.001). This association disappeared when AER was added in a multiple regression model, including SUA, age, mean arterial pressure, gender, metabolic syndrome components and glomerular filtration rate.

CONCLUSION

The results of our study showed that, in essential hypertensive subjects, there is a positive relationship between mild hyperuricaemia and aortic stiffness. This association weakened after adjustment for covariates and lost statistical significance after further correction for albuminuria.

Absence of an independent association between serum uric acid and left ventricular mass in Caucasian hypertensive women and men

BACKGROUND AND AIM

Experimentally uric acid may induce cardiomyocyte growth and interstitial fibrosis of the heart. However, clinical studies exploring the relationship between serum uric acid (SUA) and left ventricular (LV) mass yielded conflicting results. The aim of our study was to evaluate the relationships between SUA and LV mass in a large group of Caucasian essential hypertensive subjects.

METHODS AND RESULTS

We enrolled 534 hypertensive patients free of cardiovascular complications and without severe renal insufficiency. In all subjects routine blood chemistry, including SUA determination, echocardiographic examination and 24 h ambulatory blood pressure (BP) monitoring were obtained. In the overall population we observed no significant correlation of SUA with LV mass indexed for height(2.7) (LVMH(2.7)) (r = 0.074). When the same relationship was analysed separately in men and women, we found a statistically significant correlation in female gender (r = 0.27; p < 0.001), but not in males (r = -0.042; p = NS). When we grouped the study population in sex-specific tertiles of SUA, an increase in LVMH(2.7) was observed in the highest tertiles in women (44.5 ± 15.6 vs 47.5 ± 16 vs 55.9 ± 22.2 g/m(2.7); p < 0.001), but not in men. The association between SUA and LVMH(2.7) in women lost statistical significance in multiple regression analyses, after adjustment for age, 24 h systolic BP, body mass index, serum creatinine and other potential confounders.

CONCLUSIONS

Our findings do not support an independent association between SUA and LV mass in Caucasian men and women with arterial hypertension.

Global ex-situ crop diversity conservation and the Svalbard Global Seed Vault: assessing the current status

Ex-situ conservation of crop diversity is a global concern, and the development of an efficient and sustainable conservation system is a historic priority recognized in international law and policy. We assess the completeness of the safety duplication collection in the Svalbard Global Seed Vault with respect to data on the world's ex-situ collections as reported by the Food and Agriculture Organization of the United Nations. Currently, 774,601 samples are deposited at Svalbard by 53 genebanks. We estimate that more than one third of the globally distinct accessions of 156 crop genera stored in genebanks as orthodox seeds are conserved in the Seed Vault. The numbers of safety duplicates of Triticum (wheat), Sorghum (sorghum), Pennisetum (pearl millet), Eleusine (finger millet), Cicer (chickpea) and Lens (lentil) exceed 50% of the estimated numbers of distinct accessions in global ex-situ collections. The number of accessions conserved globally generally reflects importance for food production, but there are significant gaps in the safety collection at Svalbard in some genera of high importance for food security in tropical countries, such as Amaranthus (amaranth), Chenopodium (quinoa), Eragrostis (teff) and Abelmoschus (okra). In the 29 food-crop genera with the largest number of accessions stored globally, an average of 5.5 out of the ten largest collections is already represented in the Seed Vault collection or is covered by existing deposit agreements. The high coverage of ITPGRFA Annex 1 crops and of those crops for which there is a CGIAR mandate in the current Seed Vault collection indicates that existence of international policies and institutions are important determinants for accessions to be safety duplicated at Svalbard. As a back-up site for the global conservation system, the Seed Vault plays not only a practical but also a symbolic role for enhanced integration and cooperation for conservation of crop diversity.

A gap analysis methodology for collecting crop genepools: a case study with phaseolus beans

BACKGROUND

The wild relatives of crops represent a major source of valuable traits for crop improvement. These resources are threatened by habitat destruction, land use changes, and other factors, requiring their urgent collection and long-term availability for research and breeding from ex situ collections. We propose a method to identify gaps in ex situ collections (i.e. gap analysis) of crop wild relatives as a means to guide efficient and effective collecting activities.

METHODOLOGY/PRINCIPAL FINDINGS

The methodology prioritizes among taxa based on a combination of sampling, geographic, and environmental gaps. We apply the gap analysis methodology to wild taxa of the Phaseolus genepool. Of 85 taxa, 48 (56.5%) are assigned high priority for collecting due to lack of, or under-representation, in genebanks, 17 taxa are given medium priority for collecting, 15 low priority, and 5 species are assessed as adequately represented in ex situ collections. Gap "hotspots", representing priority target areas for collecting, are concentrated in central Mexico, although the narrow endemic nature of a suite of priority species adds a number of specific additional regions to spatial collecting priorities.

CONCLUSIONS/SIGNIFICANCE

Results of the gap analysis method mostly align very well with expert opinion of gaps in ex situ collections, with only a few exceptions. A more detailed prioritization of taxa and geographic areas for collection can be achieved by including in the analysis predictive threat factors, such as climate change or habitat destruction, or by adding additional prioritization filters, such as the degree of relatedness to cultivated species (i.e. ease of use in crop breeding). Furthermore, results for multiple crop genepools may be overlaid, which would allow a global analysis of gaps in ex situ collections of the world's plant genetic resources.

The impact of local extinction on genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica: consequences for the conservation of plant genetic resources

Plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. Species may also colonize the same site on multiple occasions. Here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica. We compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. Locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). Our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. However, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. Recolonized locations showed the highest level of genetic differentiation (mean F(st) = 0.2769), followed by control locations (mean F(st) = 0.0576) and experimental locations (mean F(st) = 0.0189). Similar findings were observed for Neis genetic distance between samples (d(ij) = 0.1786, 0.0400, and 0.0037, respectively). Our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. These findings also showed that control populations are not in equilibrium. Implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed.

Pacific issues of biodiversity, health and nutrition

Neglect of traditional food systems has led to serious nutrition and health problems throughout the Pacific Islands. At the same time, there is concern about the loss of traditional knowledge, customs and culture related to local foods, and of biodiversity. However, there is still a great diversity of nutrient-rich local food crops in the Pacific, along with considerable knowledge about these foods, their methods of production, harvesting, storage, and preparation. An integrated approach is needed in order to make a meaningful impact on increased production, marketing/processing and use of local food crops and foods for better health and nutrition, requiring greater collaboration between the health sector and agencies in other sectors. Priorities for action include: documentation and assessment of traditional food systems, including analysis of local foods and crop varieties for their nutrient content; innovative means of increasing awareness of the values of local foods among the general public and policy makers; conservation of rare varieties of crops and food trees and protection of the environment; and an increased focus on small-scale processing and marketing of local foods. Overriding all of this is the urgent need to mainstream consideration of these important issues into relevant national and regional policies. The rubric "Biodiversity for Health and Nutrition" incorporates all of these issues and provides a framework within which all partner agencies can be involved.

The Role of Geographic Analysis in Locating, Understanding, and Using Plant Genetic Diversity

The genetic structure of an organism is shaped by various factors, many of which vary significantly over space. In this chapter, we provide insight on how studying geographic patterns may contribute to an improved understanding of variability in genetic structure. We first review the theoretical background on how differences in genetic structure may be generated through processes that are inherently variable over space. We then present novices with some basics on how geographic information systems (GIS) may be adopted to study this variation, including advice on software, data, and the type of research questions that might be addressed. The chapter finishes with a brief review of how spatial analysis has contributed to the conservation and use of plant genetic resources, through an understanding of spatial patterns in species distribution and genetic structure. We conclude that spatial variation is a factor often overlooked in genetic studies and one that merits greater consideration. With the advent of functional genomics and improved quantification of adaptive traits, spatial analysis may be key in understanding variation in genetic structure through careful analysis of genotype-environment interactions.

Construction, expression, and characterization of a baculovirally expressed catalytic domain of human matrix metalloproteinase-9

We report DNA construction, baculovirus expression, and partial characterization of a minienzyme form of the human matrix metalloproteinase-9 (MMP-9). The MMP-9 minienzyme gene construct consisting of the pre, pro, and catalytic domains of the MMP-9 was introduced into Sf9 insect cells using a baculovirus expression system. The expression of the recombinant MMP-9 minienzyme was estimated to be approximately 0.8 mg/L of cell medium. The recombinant protein was purified using a single-step gelatin-Sepharose affinity column and yielded a highly stable and active minienzyme with gelatinolytic activity. Moreover, two interesting findings related to MMP-9 interactions with heparin and TIMP-1 resulted from our studies. First, the pro and catalytic domains of the human MMP-9 are not sufficient for heparin affinity. Second, in contrast to the prevailing consensus, TIMP-1 blockade of the enzymatic activity of MMP-9 does not require prior binding to the C-terminus of its MMP-9 protein substrate.

Cortical blood flow and cerebral perfusion pressure in a new noncraniotomy model of subarachnoid hemorrhage in the rat

BACKGROUND AND PURPOSE

Acute cerebral ischemia after subarachnoid hemorrhage (SAH) is a major cause of morbidity whose precise etiology is unclear. The purpose of this study was to examine the relationships between cerebral perfusion pressure (CPP) and cortical blood flow during SAH using a new experimental model in the rat.

METHODS

CPP (mean arterial pressure minus intracranial pressure), cortical laser-Doppler flowmetry (LDF), and electroencephalogram were continuously recorded during and after SAH in 16 ventilated rats. SAH was produced by advancing an intraluminal suture from the external carotid artery through the internal carotid artery to perforate the vessel near its intracranial bifurcation.

RESULTS

Eight rats (50%) died within 24 hours of SAH. In all rats, blood was widely distributed throughout the basal, convexity, and interhemispheric subarachnoid spaces and throughout the ventricular system. CPP decreased after SAH at an initial rate of 1.1 +/- 0.2 mm Hg/s, reaching its nadir 59 +/- 9 seconds after the onset of SAH. During the same period, LDF fell at a rate of 1.4 +/- 0.3%/s (P = NS vs CPP). After reaching its nadir, CPP rose at a rate of 0.4 +/- 0.01 mm Hg/s, but LDF continued to fall at 0.2 +/- 0.03%/s (P < .05 vs CPP) reaching a nadir of 21.7 +/- 2.5% significantly later than CPP (189.5 +/- 39 s after SAH, P < .05). No correlation was found between peak changes in CPP and LDF. Electroencephalogram activity followed the changes in LDF, reaching nadir values 289 +/- 55 seconds after SAH.

CONCLUSIONS

These findings demonstrate that although reduced CPP causes the initial decrease in cortical blood flow after SAH, secondary reductions occurring after CPP has reached its nadir are caused by other factors such as acute vasoconstriction. This noncraniotomy model of SAH in the rat has several advantages over existing models.

Pharmacologic-guided trial of sequential methotrexate and thioguanine in children with advanced malignancies

PURPOSE

Based on in vitro studies that have shown synergistic effects of sequential administration of methotrexate (MTX) and thioguanine (6-TG), we conducted a pharmacologically guided trial of sequential MTX and 6-TG to determine the following: (1) the maximum-tolerated dose (MTD) of 6-TG; (2) the nature of the dose-limiting toxicity; and (3) the modulation effect of MTX on 6-TG given by this sequence and schedule.

PATIENTS AND METHODS

Thirty-one children with advanced malignancies (acute leukemia, n = 10; lymphoma n = 10; and solid tumors, n = 11) were treated weekly for 3 weeks with a 2-week rest; treatment consisted of a fixed dose of MTX (30 mg/m2 over 24 hours) followed by a 2-hour infusion of 6-TG in escalating doses.

RESULTS

Measurement of plasma MTX, 6-TG, and mononuclear 5-phosphoribosyl-1-pyrophosphate (PRPP) levels indicates that the desired biochemical modulation and serum levels were achieved. Nonhematologic toxicities were mild and the dose-limiting toxicity was bone marrow depression. A 300-mg/m2 dose of 6-TG with MTX is considered the MTD. Responses were noted in patients with lymphoma.

CONCLUSION

Encouraging antitumor effects were produced with this regimen in heavily pretreated patients with lymphoma, particularly Hodgkin's disease (HD). The durations of responses were 17, 13+, 12, 9, and 7+ months. A phase II trial of the MTX/6-TG combination is warranted for the treatment of relapsed lymphoma.

[Coronary transluminal angioplasty using 6-french diagnostic catheters. A preliminary study]

This preliminary study was undertaken to assess the potential indication and limitations of the use of 6 French guiding catheters for percutaneous transluminal coronary angioplasty (PTCA). Between September 1992 and October 1993, 100 consecutive patients with an average age of 64 +/- 11 years underwent 6 F angioplasty for: stable angina (38.7%), unstable angina (32.4%), non Q-wave or infarction recanalized by thrombolytic therapy (18%), and acute myocardial infarction (10.8%). Eighty per cent of the pTCAs were performed immediately after diagnostic coronary angiography. Single vessel disease accounted for 93.7% of cases. Of the 118 lesions treated, 46.6% were types A or B1, 44.9% were type B2 and 8.4% were type C. The success rate of 6 F PTCA was 96.4% using an average of 1.08 guides and 1.25 balloon catheters per patient. Stenosis decreased from 83 +/- 10% to 26 +/- 16%. There were 4 technical failures: in 1 case it was not possible to pass a chronic occlusion, in 1 case coronary dissection was complicated by infarction, and in 2 cases a 7 F guiding catheter was required for successful PTCA. No patients required emergency coronary bypass surgery and there were no fatalities during the procedure. Four patients required perfusing balloon catheters and 8 were stented with a Palmaz-Schatz endoprosthesis with the 6 F catheter. These results are comparable to those obtained with larger diameter guiding catheters. In view of the good coronary ostial tolerance, the lower rate of local complications at the site of arterial puncture and the possibility of earlier mobilisation of patients after the procedure, the indications for 6 F PTCA should increase.

Nucleotide sequence of a transactivating Bombyx mori nuclear polyhedrosis virus immediate early gene

The open reading frame (ORF) of 1572 bp contained in the 3.8 kb ClaI fragment of BmNPV encodes a viral regulatory protein which transactivates the delayed early AcMNPV 39K gene. Transactivation is induced in uninfected cells following transfection with a plasmid containing only the ClaI fragment. Hitherto immediate early gene promoter activity of the included 631 bp leader sequence is evident since no other viral elements are needed for the transcription of the regulatory gene.

Reciprocal ST segment changes in acute inferior myocardial infarction: clinical, haemodynamic and angiographic implications

Reciprocal ST segment changes are frequent during acute inferior myocardial infarction, yet their significance remains controversial. In order to investigate the implications of these changes, the ECG obtained on admission for 83 patients with acute inferior myocardial infarction was compared with the clinical course and the results of angiographic and coronary arteriographic studies performed an average of 3 weeks after the onset of symptoms. Group 1 consisted of 59 patients with at least 1 mm of horizontal on downsloping ST segment depression in at least 1 of leads V1 to V4. Groups 2 consisted of 24 patients without precordial ST depression in this area. Group 1 patients were generally older than group 2 patients (59.6 +/- 6.4 versus 54 +/- 5.3 yr, P less than 0.01) had higher total creatine kinase (CK) levels and MB fractions (1835 +/- 940 versus 875 +/- 305, P less than 0.01, 269 +/- 102 versus 95 +/- 35 for MB fraction) and more complications during the hospital course (80% versus 38% P less than 0.01) and greater left ventricular dysfunction (ejection fraction 52.2 +/- 6% for group 1 versus 59.2 +/- 7% for group 2; cardiac index 2.75 +/- 0.41 min-1 m-2 for group 1 versus 3.25 +/- 0.31 min-1 m-2 for group 2 P less than 0.005). No difference was observed on biplane angiography as far as left ventricular wall kinesis was concerned.(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance of ST segment depression in the precordial leads during the acute phase of inferior myocardial infarction]

Reciprocal changes of the ST segment in the acute phase of inferior myocardial infarction are common but their significance remain controversial. We studied this problem by comparing the ECG on admission of 83 patients with acute inferior myocardial infarction, with the clinical outcome and haemodynamic and angiographic data obtained on average 3 weeks after the onset of symptoms. Fifty nine patients (Group I) had ST depression greater than or equal to 1 mm in at least one of the leads V1 to V4; 24 patients (Group II) had no ST depression in this territory. The patients in Group I were older (59.6 +/- 6.4 vs 54 +/- 5.3 years, p less than 0.01), had higher total CPK (1 835 +/- 940 vs 875 +/- 305, p less than 0.01) and MB fractions (269 +/- 102 vs 95 +/- 35), more complications during the hospital period (80%, mainly haemodynamic vs 38%, p less than 0.01) and more severe left ventricular dysfunction: ejection fraction 52.2 +/- 6% vs 59.2 +/- 7%, p less than 0.05; cardiac index 2.75 +/- 0.4 l/min/m2 vs 3.25 +/- 0.3 l/min/m2, p less than 0.005). There was no difference in left ventricular wall motion between the groups on biplane angiography. However, coronary angiography showed left coronary disease to be more common in Group I (84%) than in Group II (37%), p less than 0.005. Left anterior descending and left circumflex disease was equally common. Patients with persistent ST depression after 48 hours had lower ejection fractions than those in whom it regressed within 48 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

[Immediate coronary angioplasty in the acute phase of myocardial infarction. French multicenter study: December 1983]

Following the introduction of intracoronary thrombolysis in the acute phase of myocardial infarction (AMI), transcutaneous coronary angioplasty (TCA) was originally conceived as a logical complementary procedure to treat residual stenosis and so prevent the frequent post-thrombolysis reocclusion (20-30 p. 100 of cases). With increasing experience TCA of first intent appeared rational, more rapid and effective, ensuring coronary recanalisation (CR), suppression of residual stenosis and the prevention of reocclusion in the same procedure with with the objective of reducing the number of coronary bypass grafts (CBG) in patients with single vessel disease. A French multicentre study of 22 cases was organised by 9 centres. The average period between onset of symptoms and intervention was 2 hours 10 mins (range 30 mins-5 hours 30 mins). The average duration of the procedure was only 30 mins. 16 patients had anterior and 6 patients inferior AMI. Coronary angiography showed 12 occlusions (54.5 p. 100) and 10 sub-occlusions with 6 cases of delayed opacification. All patients had successful initial TCA with no major complications. The arterial occlusions decreased from 100 p. 100 to 31 p. 100 and the subocclusions from 94 to 12 p. 100. 2 patients died in the hospital period, one at the 48th hour of controlateral AMI and the other one at the 5th day of reocclusion. Three patients developed reocclusion at the site of the original TCA. Complete regression of ECG changes was observed in 31.8 p. 100 of cases. Complete recovery of normal left ventricular function was observed in 8 of the 17 patients who underwent follow-up investigations (47 p. 100 of cases).(ABSTRACT TRUNCATED AT 250 WORDS)

[Accentuation of myocardial ischemia during coronary recanalization in the acute phase of myocardial infarction]

Coronary recanalisation during the acute phase of myocardial infarction, especially by in situ infusion of thrombolytic agents, is accompanied in most cases by rapid regression of chest pain and a reduction in the degree of ST elevation. However, a multicentre retrospective study of 104 attempts at recanalisation, including 78 successful procedures, showed in 10 cases (12.8 p. 100), an apparently paradoxical accentuation of the chest pain with or without increased ST elevation, at the time of angiographically demonstrable recanalisation. This phenomenon may be interpreted as being the result of aggravation of the ischaemia of the border zone, the objective of therapy. Several pathogenic hypotheses, all with experimental proof, may be suggested to explain these observations (haemorrhagic infarction, non reperfusion, ischaemic contraction due to massive intracellular flow of calcium, etc.). It is usually associated with arrhythmias and may be considered to be a reliable sign of recanalisation. It may also explain certain cases of persistence of chest pain and ECG changes despite the demonstration of a permeable epicardial artery on initial coronary angiography.

[Coronary angioplasty immediately after intracoronary thrombolysis during the acute phase of myocardial infarction]

Since the introduction of intracoronary thrombolysis in the acute phase of myocardial infarction, all workers have observed a high incidence of coronary reocclusion (about 20%) essentially in the first hours and days after coronary recanalisation (CR). This had led to some groups carrying out transluminal coronary angioplasty (TCA) at the same time as CR by thrombolysis in situ to treat significant residual postthrombolysis stenosis. This french multicentre study carried out in 5 centres concerned 9 men (average age: 46.1 years) with 5 anterior infarcts (total thrombosis of the LAD artery) and 4 inferior infarcts (total thrombosis of the right coronary artery-RCA). Intracoronary trinitrate was ineffective in relieving the occlusion in all cases. In 5 cases, the thrombolytic protocol was streptokinase (SK) 3 000 u/min for 60 minutes; in the other 4 cases, the plasminogen-urokinase (Pg-UK) protocol was used. Thrombolysis was successful in all 9 cases. The results of TCA performed at the same time were also good (8/9 successes; 4 LAD and 4 RCA) without any complications during the procedure. There was only one immediate post-TCA reocclusion on a LAD artery. In all cases the initial ECG appearances of infarction remained, CR only appearing to prevent extension of the necrosis. The successful results of CR + TCA were maintained in 6 out of 7 patients reinvestigated 2 days to 6 months (average 6 months) after the initial procedure: the only case of reocclusion occurred after 48 hours on a RCA. The overall procedure never exceeded 2 hours.

[Hemodynamic study during 48 hours of delayed-release isosorbide dinitrate (repeated oral administration) in the acute phase of myocardial infarction complicated by left ventricular insufficiency]

The aim of this study was to evaluate the haemodynamic effects of slow release isosorbide dinitrate (IDN) 40 mg oral preparation over a 48 hour period in patients with acute myocardial infarction complicated by left ventricular failure. Fourteen patients (8 male, 6 female) were treated by repeat dose ISD (8 hourly) and the haemodynamic changes were recorded at 1 hr, 2 hrs, 6 hrs, 12 hrs, 24 hrs, and 48 hrs. After 48 hours treatment the heart rate was unchanged; mean arterial blood pressure fell from 109.5 +/- 5.6 mmHg to 93.5 +/- 6.2 mmHg (-15%) (p less than 0.01). Cardiac index rose from 2.4 +/- 0.57 1/min/m2 to 2.8 +/- 0.65 1/min/m2 (+16%) (NS); diastolic pulmonary artery pressure fell from 22.5 +/- 7.07 mmHg to 13.7 +/- 4.5 mmHg (-39%) (p less than 0.003); systolic pulmonary artery pressure fell from 40.5 +/- 12.2 mmHg to 28.6 +/- 11.6 mmHg (-30%) (NS). Systemic vascular resistance fell from 2 095.2 +/- 63 dynes/s/cm5 to 1 537 +/- 60 dynes/s/cm5 (-22.3%) (NS). Finally, total pulmonary resistance fell from 561.9 +/- 15 dynes/s/cm5 to 301.9 +/- 14.5 dynes/s/cm5 (-47%) (p less than 0.003). The most valuable effect was therefore the reduction in left ventricular filling pressures which was maximal after about 48 hours. Two groups of patients were identified according to the clinical outcome. The patients in Group I (11 cases) were improved by the fall in diastolic pulmonary artery pressure, the rise in cardiac index and the reduction of systemic valvular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intracoronary thrombolysis in myocardial infarction]

In more than 70% of the cases thrombi in the coronary arteries responsible for myocardial infarction can be dissolved by intracoronary injection of a fibrinolytic agent. For the left ventricular function to improve thrombolysis must be performed within 4 hours of thrombus formation; when performed later, results are inconstant. The risks of arteriography and thrombolysis (mostly dysrhythmias and haemorrhage) are real but acceptable. The mortality rate is lower than with conventional treatment. Improvement in left ventricular global ejection fraction is more pronounced in cases with collateral circulation and when thrombolysis is performed at an early stage. Thrombosis recurs within a few days in 15-20% of the cases. This can be prevented by aorto-coronary bypass or transluminal dilation of the stenotic vessel with a balloon catheter, either of these being carried out very early in cases with tight stenosis or delayed when the stenosis is significant but not life-threatening. A multicentre trial should be set up to find out whether intracoronary thrombolysis improves long-term survival and prevents late complications. But even if this were true, it should still be demonstrated that the method is as effective and safe as intravenous thrombolysis.

[Coronarography by percutaneous puncture of the axillary artery. Value in arteriopathies of the lower limbs]

Coronary angiography by a percutaneous femoral approach using the Judkins-Bourassa technique with special preformed catheters is widely used. This approach is potentially dangerous or impossible in patients with severe lower limb arteriosclerosis even after operation and so the investigation has to be done by Sones' technique (denudation of the humeral artery). There is, however, another upper limb approach which does not involve arterial denudation: percutaneous right or left axillary artery catheterisation. This paper reports the experience of a multicentre study of this method in 105 patients. This study is of interest as an arterial catheter introducer was used which, does not compress the artery, prevents bleeding when the catheter has to be changed and reduced the risk of thromboses or laceration of the axillary artery. 73 of the 105 patients had lower limb arteriosclerosis 5 had aortic aneurysms and 1 patient had a previous history of femoral artery embolism. There was a primary indication for this approach in 21 cases. The left axillary artery was used in 83 cases (79%) and the right axillary artery in 22 cases (21%). The coronary catheters were those usually used with the femoral approach. The left side was chosen preferentially as it avoided the brachiocephalic trunk and facilitated the catheterisation of the coronary ostia and of aorto-coronary bypass grafts. Selective catheterisation of the left coronary artery was achieved in 21 out of 22 cases (95%) and of the right coronary artery in all 22 cases (100%) by the right axillary route. Both left and right coronary arteries were selectively catheterised in all cases by the left axillary approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective coronary arteriography by percutaneous transaxillary approach

Coronary angiography by the percutaneous femoral approach is widely used. This technique is potentially dangerous or impossible in patients with advanced arterial disease of the lower limbs, whether or not surgically treated. In these cases, percutaneous left or right axillary approach is an alternative to brachial approach. In this article, we report our multicenter experience involving 120 patients. The left axillary artery was used in 94 cases (78%) and the right in 26 cases (22%). We used performed coronary catheters usually associated with the femoral approach. The left axillary artery was used preferentially since this avoids catheterization of the innominated trunk and allows easier catheterization of the coronary ostia and aortic ends of aorto-coronary bypass grafts. The routine use of a sheath (arterial introducer) avoided arterial compression during catheterization, prevented hemorrhagic suffusion when the catheters were exchanged, and reduced the risk of thrombosis or laceration of the axillary artery. There were no failures in the catheterization of the axillary artery and no complication was observed during or after the procedure. Axillary percutaneous technique appears to have the following advantages over the brachial arteriotomy: 1) Investigation time is equivalent to the time needed for the femoral percutaneous approach. 2) There is the possibility of lateral and simultaneous bi-plane angiograms. 3) Arterial puncture is preferable to arteriotomy. The axillary approach could also be used for percutaneous transluminal coronary angioplasty.

[Comparative study of endocavitary recording and the 24-hour electrocardiogram in the study of sinus function. Apropos of 174 cases]

We compared the results of electrophysiological investigations of sino-atrial node function in a series of 174 patients (including the sino-atrial conduction time (SACT) according to the method of Narula and Strauss, the corrected sino-atrial recovery time (CSART) and, in, 22 patients, the atropine test) with the results of 24 hour Holter monitoring. 73 patients presented a pathological Strauss curve, 47 had a prolonged SACT (Strauss' method) and 19 had a pathological CSART. Of the 22 bradycardic patients, the injection of atropine relieved the bradycardia in 45.5 per cent of cases. 19 patients showed signs of sino-atrial node dysfunction on the 24 hour Holter recording. Of the 35 patients with a surface electrocardiogram (ECG) suspicious of sino-atrial node dysfunction, 21 (60%) had a prolonged SACT and 13 (37.1%) had a pathological CSART: 15 of them (42.8%) showed major electrophysiological abnormalities and 19 (54.3%) had a positive Holter. In two-thirds of the cases of pure sino-atrial bradycardia, the results of electrophysiological and Holter investigations were normal; in 50 per cent of cases of sino-atrial block and/or pause on the surface ECG, major abnormalities were found on both electrophysiology and the Holter monitor. The SACT, estimated according to the method of Strauss, is discorsdant with the SACT estimated according to Narula's method in 46 p. cent of cases. It seems that Strauss' SACT was more sensitive in our study. In 102 cases (59.3%), the SACT and the CSART were concordant. In 10 cases, the SACT was normal while the CSART was pathological and in 42 cases, the SACT was pathological while the CSART was normal.(ABSTRACT TRUNCATED AT 250 WORDS)

[Implantation of permanent cardiac pacing electrodes by the retropectoral transvenous approach. Results of a series of 152 cases]

When the cephalic vein is unsuitable for the introduction of pacing electrodes, the retropectoral veins near the external border of pectoralis major near its subclavian attachment, approached through the same incision, may provide a suitable alternative. It was not possible to catheterise the cephalic vein in 23,8% of 756 consecutive implantations of endocavitary pacing electrodes. The retropectoral veins were looked for in 172 cases and found and used in 159 cases (92,4%). This percentage of success increased to 97,6% in the latter 83 attempts. These veins are usually very distensible. No complications or accidents were recorded. The only disadvantage was the relatively long dissection time. The stability of the pacing electrodes with this approach was excellent as reoperation was only required in 3% of cases (2 displacements and 3 exit blocks or pericardial migrations). This approach is therefore practicable in the large majority of cases in which the cephalic vein cannot be used. The multiplicity of the retropectoral veins should allow the introduction of two electrodes if sequential atrioventricular pacing were to be chosen. In addition, this approach would be useful when an atrial pacing electrode is to be added to a preexisting ventricular pacing electrode and one hesitates to puncture the subclavian vein because of the risk of damaging the electrode already in place. When direct subclavian puncture is the technique of choice of the operator, the retropectoral veins may be used when the subclavian approach is contraindicated or impossible. In any case, denudation of the retropectoral veins leads to fewer incidents than when the latter approach is used.