Aspects of the reproductive biology of clintonia borealis (Ait.) Raf.

The rhizome of Clintonia borealis tAit.) Raf, was shown to store large quantities of total nonstructural carbohydrates up until fall dormancy and to draw upon these reserves during the spring growth period, however the level of decline and rate of decline are not necessarily the same from year to year. Older rhizome segments participate in TNG storage, demonstrating high levels in the fall and low levels in the spring. In addition, roots are also capable of storing TNG and probably provide an important secondary reserve. For a typical population in Northwestern Ontario, 3-leaved specimens were the most important members since they provided the greatest contribution towards the total population as well as the most flowering individuals. Plants with high leaf numbers produced the most rhizomes and were the ones most likely to be fertile. Population makeup, with respect to the number of plants in each leaf number category and the percentage of individuals in flower remains relatively constant from year to year for populations growing in a stable environment. Leaf number is determined in the fall by the number of preformed leaves present in the rhizome bud. Leaves which do not reach this level of development, i.e., primordial leaves, abort the following spring. Similarly an inflorescence in the bud must have matured enough to possess a well developed stipe before the onset of dormancy, otherwise it too will abort in the spring. Plants growing in open sites are most likely to be fertile. This phenomenon may be related to TNC storage since plants growing in the open are probably the most active photosynthetically and in turn producing the most TNC. A minimum or threshold level of TNC for inflorescence production in C. borealis is suggested. Insect mediated cross pollination is the principal pollination mechanism in Clintonia borealis; however, the species still possesses a capacity for self pollination. A distinct correlation exists between berry volume and the number of mature seeds contained. This is interpreted as a reproductive strategy allowing maximum seed dispersal by animal vectors since the most attractive fruit contain the greatest number of seeds

Multiple Endocrine Tumors Associated with Germline MAX Mutations:Multiple Endocrine Neoplasia Type 5?

Context: Pathogenic germline MAX variants are associated with pheochromocytoma and paraganglioma (PPGL), pituitary neuroendocrine tumors and, possibly, other endocrine and nonendocrine tumors. Objective: To report 2 families with germline MAX variants, pheochromocytomas (PCs) and multiple other tumors. Methods: Clinical, genetic, immunohistochemical, and functional studies at University hospitals in Australia on 2 families with germline MAX variants undergoing usual clinical care. The main outcome measures were phenotyping; germline and tumor sequencing; immunohistochemistry of PC and other tumors; functional studies of MAX variants. Results: Family A has multiple individuals with PC (including bilateral and metastatic disease) and 2 children (to date, without PC) with neuroendocrine tumors (paravertebral ganglioneuroma and abdominal neuroblastoma, respectively). One individual has acromegaly; immunohistochemistry of PC tissue showed positive growth hormone-releasing hormone staining. Another individual with previously resected PCs has pituitary enlargement and elevated insulin-like growth factor (IGF-1). A germline MAX variant (c.200C>A, p.Ala67Asp) was identified in all individuals with PC and both children, with loss of heterozygosity in PC tissue. Immunohistochemistry showed loss of MAX staining in PCs and other neural crest tumors. In vitro studies confirmed the variant as loss of function. In Family B, the proband has bilateral and metastatic PC, prolactin-producing pituitary tumor, multigland parathyroid adenomas, chondrosarcoma, and multifocal pulmonary adenocarcinomas. A truncating germline MAX variant (c.22G>T, p.Glu8∗) was identified. Conclusion: Germline MAX mutations are associated with PCs, ganglioneuromas, neuroblastomas, pituitary neuroendocrine tumors, and, possibly, parathyroid adenomas, as well as nonendocrine tumors of chondrosarcoma and lung adenocarcinoma, suggesting MAX is a novel multiple endocrine neoplasia gene.</p