Gene disruption of p27(Kip1) allows cell proliferation in the postnatal and adult organ of corti

Hearing loss is most often the result of hair-cell degeneration due to genetic abnormalities or ototoxic and traumatic insults. In the postembryonic and adult mammalian auditory sensory epithelium, the organ of Corti, no hair-cell regeneration has ever been observed. However, nonmammalian hair-cell epithelia are capable of regenerating sensory hair cells as a consequence of nonsensory supporting-cell proliferation. The supporting cells of the organ of Corti are highly specialized, terminally differentiated cell types that apparently are incapable of proliferation. At the molecular level terminally differentiated cells have been shown to express high levels of cell-cycle inhibitors, in particular, cyclin-dependent kinase inhibitors [Parker, S. B., et al. (1995) Science 267, 1024-1027], which are thought to be responsible for preventing these cells from reentering the cell cycle. Here we report that the cyclin-dependent kinase inhibitor p27(Kip1) is selectively expressed in the supporting-cell population of the organ of Corti. Effects of p27(Kip1)-gene disruption include ongoing cell proliferation in postnatal and adult mouse organ of Corti at time points well after mitosis normally has ceased during embryonic development. This suggests that release from p27(Kip1)-induced cell-cycle arrest is sufficient to allow supporting-cell proliferation to occur. This finding may provide an important pathway for inducing hair-cell regeneration in the mammalian hearing organ.

Gastrointestinal stromal tumors and leiomyomas in the dog: a histopathologic, immunohistochemical, and molecular genetic study of 50 cases

Fifty canine gastrointestinal (GI) mesenchymal tumors were examined to determine the occurrence of leiomyomas (LM) and GI stromal tumors and to compare their clinicopathologic features. Twenty-one tumors (42%) were histologically reclassified as gastrointestinal stromal tumors (GISTs) and 29 tumors (58%) as LMs on the basis of their histologic similarity with homologous human tumors. The GISTs occurred equally in males and females, with a mean age of 11 years (range 5-14 years). Five GISTs (24%) were associated with clinical signs and six (29%) had metastasis in liver or abdominal cavity. The GISTs occurred in large intestine (10, 48%), small bowel (six, 29%), stomach (four, 19%), and mesentery of small intestine (one, 5%). Histologically, they were highly cellular spindle, or less commonly epithelioid tumors with mitotic rates ranging from 0 to 19 per 10 HPF. Eleven tumors (52%) were positive for CD117 (KIT); seven (33%) were positive for smooth muscle actin but none for desmin and S-100 protein. Sequences of KIT exon 11, often mutated in human GISTs, were evaluated from four GISTs. Deletion of Try556-Lys557 coexisting with duplication of Gln555 in one case of GIST and T to C transition resulting in substitution of Pro for Leu575 in another were identified. The LMs occurred predominantly in males (82%) with a mean age of 11 years (range 8-17 years). Nine tumors (31%) had associated clinical signs. They occurred in the stomach (22, 76%), esophagus (four, 14%), and intestines (three, 10%); all were paucicellular, had no mitoses, and were composed of mature smooth muscle cells. Twenty-eight (97%) were positive for smooth muscle actin and 18 (62%) for desmin but none for CD117 and S-100. Both GISTs and true LMs occur in the GI tract of dogs. Both tumors have distinctive pathologic features.

Neural networks in clinical medicine

Neural networks are parallel, distributed, adaptive information-processing systems that develop their functionality in response to exposure to information. This paper is a tutorial for researchers intending to use neural nets for medical decision-making applications. It includes detailed discussion of the issues particularly relevant to medical data as well as wider issues relevant to any neural net application. The article is restricted to back-propagation learning in multilayer perceptrons, as this is the neural net model most widely used in medical applications.

Road rage: a psychiatric phenomenon?

BACKGROUND

Road rage is a concept recently popularised by the press. An association with psychiatric illness is implied from reports of such drivers being "mad". Previous literature has demonstrated a link between road traffic accidents and mental illness. This study examines the relationship between road rage and psychiatric morbidity. It aims to estimate the prevalence of road rage by self-report and elucidate demographic and psychiatric factors associated with road rage.

METHOD

This is a cross-sectional study of attendees at general practice clinics that examines self-reported road rage and psychiatric morbidity. Assessment was based on the total score on the Clinical Interview Schedule (revised version; CIS-R), Aggression Questionnaire, Screening Test for Comorbid Personality Disorders, Alcohol Use Disorders Identification Test and Life Events Schedule.

RESULTS

Fifty-three percent of 131 subjects reported a recent incident of road rage. Perpetrator and victim groups differed from controls. Perpetrators had increased aggression scores and psychiatric morbidity. There was a strong association with male sex and illicit drug use, and a strong negative association with driving experience. A weaker association was found with youth. Victims showed increased psychiatric morbidity and were more likely than perpetrators to seek help for emotional problems. Life events stress, social class, alcohol use and personality disorder had no significant effect.

CONCLUSION

There is an association between road rage and psychiatric morbidity.

Advances in the molecular genetic analysis of the flax-flax rust interaction

The L6 and M rust-resistance genes, representing two of the five rust-resistance gene loci in flax (Linum usitatissimum), have been cloned. The molecular data are fully consistent with earlier genetic data: the L locus is a single gene with multiple alleles expressing different rust resistance specificities, and the M locus is complex, containing an array of about 15 similar genes. Thus, while L6 and M resistance genes have 86% nucleotide identity, their locus structure is very different. These genes encode products belonging to the nucleotide binding site-leucine-rich repeat class of disease-resistance proteins. Analysis of alleles from the L locus and chimeric genes is providing evidence suggesting that important specificity determinants occur in the C-terminal half of the proteins, the region containing the leucine-rich repeats. The isolation and characterization of the rust (Melampsora lini) avirulence genes that correspond to the cloned rust-resistance genes is one of the major challenges remaining to the understanding of this system.

Determinants of carotid artery wall thickening in young patients with Type 1 diabetes mellitus

To investigate associations between early atherosclerosis and possible risk factors for it in young patients with established Type 1 diabetes mellitus (DM), we measured the combined intima-media thickness (IMT) of the common carotid arteries with high resolution ultrasound in 310 young patients (age < or = 40 years, mean 27.9 +/- 6.5) with a diabetes duration > or = 2 years, and in two control groups of similar age (control 1:40 healthy subjects, control 2: 40 Type 1 DM recently diagnosed patients). Albumin excretion rate and lipids (total cholesterol and triglycerides) were measured and retinopathy and hypertension (systolic blood pressure > 140 or diastolic blood pressure > 90 mmHg) sought in the patients. Mean maximum IMT was 0.52 +/- 0.06 mm in control group 1 and 0.50 +/- 0.05 mm in control group 2 with a mean difference of 0.02 mm (95% CI: -0.01, 0.04). The more established Type 1 DM patients had a significantly greater IMT (0.57 +/- 0.13 mm, p < 0.001) than both control groups. In a subgroup analysis, patients with microvascular diabetic complications (n = 99) had a significantly greater IMT (0.63 +/- 0.17 vs 0.55 +/- 0.10 mm, p < 0.001) than those without (n = 211). In a multiple linear regression analysis with a significance level of < or = 0.10, the carotid artery IMT of our established diabetic patients was related to age, male gender, triglycerides and nephropathy, suggesting the latter as the main diabetes-specific risk for intima-media thickening in young Type 1 DM patients.

Novel sulfonate analogues of combretastatin A-4: potent antimitotic agents

Sulfonate analogues of combretastatin A-4 have been prepared. These compounds compete with colchicine and combretastatin A-4 for the colchicine binding site on tubulin and are potent inhibitors of tubulin polymerization and cell proliferation. Importantly, these compounds also inhibit the proliferation of P-glycoprotein positive (+) cancer cells, which are resistant to many other antitumor agents.

Limited joint mobility in type 1 diabetic patients: associations with microangiopathy and subclinical macroangiopathy are different in men and women

OBJECTIVE

To study the relationship of limited joint mobility (LJM) in type 1 diabetic patients with microvascular complications, hypertension, and early atherosclerosis and to determine whether sex has an influence on possible associations.

RESEARCH DESIGN AND METHODS

A total of 335 consecutive unselected patients (191 women and 144 men), aged 14-40 years, were studied for LJM, retinopathy, nephropathy (stages III and IV), and hypertension. Standard laboratory tests were performed; the intima-media thickness (IMT) of the carotid arteries, which reflects the extent of early atherosclerosis, was measured by high-resolution ultrasound, and plaques were identified.

RESULTS

The frequency of LJM was 33.7% (29.8% in women and 38.9% in men). Subjects with LJM had a longer diabetes duration (P < 0.001) than those without (women 16.7 +/- 9.1 vs. 10.3 +/- 6.0 years; men 15.0 +/- 9.0 vs. 9.4 +/- 6.3 years). Age, HbA1c, lipids, and systolic/diastolic blood pressure were not different between men and women with or without LJM. Men with LJM had a higher albumin excretion rate (37.1 vs. 13.1 microg/min, P < 0.05) than those without LJM and showed a higher risk of proteinuria (odds ratio 1.8, 95% CI 1.2-2.7; P < 0.05), retinopathy (2.4, 1.7-3.5; P < 0.001), and hypertension (1.7, 1.2-2.6; P < 0.05). The occurrence of these complications was not different between women with and without LJM, but only women with LJM had a greater IMT (0.59 +/- 0.13 vs. 0.55 +/- 0.10 mm, P < 0.05) and a higher risk of plaques (odds ratio 2.1, 95% CI 1.3-3.4; P < 0.05) than women without LJM. In a multiple logistic regression analysis, adjusted for age and diabetes duration, male sex independently predicted the presence of LJM. Moreover, LJM proved to be an independent predictor of retinopathy in men only.

CONCLUSIONS

LJM is an indicator of microvascular disease in men, and LJM is associated with early macrovascular disease in women.

The effect of electrical stimulation on post mortem myofibrillar protein degradation and small heat shock protein kinetics in bull beef

This study aimed to determine the effect of electrical stimulation and ultimate pH (pHu) on shear force, myofibrillar protein degradation and small heat shock protein (sHSP) concentrations in M. longissimus lumborum (LL). The LL from both sides of carcasses (n=15) was excised with low voltage electrical stimulation (ES) applied to an LL muscle from one side, while the opposing LL muscle was not stimulated (NS). Muscles were categorised into low (pHu<5.8), intermediate (5.8≤pHu<6.2) and high pHu (pHu≥6.2) and aged for up to 28days post mortem at -1.5°C. High pHu meat tenderised faster which corresponded with the faster degradation of titin and desmin in this group compared with low and intermediate pHu meat. Electrical stimulation significantly affected the variable levels of αβ-crystallin and HSP20 with higher concentrations of these sHSP in ES muscles at later ageing timepoints compared with NS muscles.

Synthesis and antitumor activity of new platinum complexes

A new type of antitumor platinum complex has been prepared and examined for antitumor activity against L1210 leukemia both in vitro and in vivo. The coordination environment of platinum in these complexes consists of three anionic chloride ions and a positively charged amine. The positive charge is introduced by monoprotonation or monoalkylation of a diamine. Platinum(IV) derivatives have been prepared for several of the complexes, and a water-soluble sulfate derivative has been prepared for one of them. Several of these complexes exhibit significant in vitro activity, and trichloro(3-aminoquinuclidinium)platinum(II) (QTP) exhibits significant in vivo activity as well. An increase in life span of approximately 40% has been observed using QTP. QTP is toxic at doses slightly in excess of effective doses.

Dietary toxicity of calcium β-hydroxy-β-methyl butyrate (CaHMB)

HMB, 3-hydroxy-3-methyl butyrate, is of interest as a dietary supplement and a possible component of functional and medical foods. The purpose of this study was to evaluate the toxicity of the calcium salt of HMB, calcium 3-hydroxy-3-methyl butyrate (CaHMB, monohydrate, food grade), when administered daily in the diet of rats for at least 90 days. Male and female Crl:CD (SD)IGS BR animals were assigned to four groups. Each group received diets containing the carrier or 1%, 2%, or 5% of CaHMB mixed with diet. Assessment of toxicity was based on mortality, clinical observations, body weights, food consumption, and clinical and anatomic pathology evaluations. Administration of CaHMB in basal diet for 91 days was tolerated well. There were no unscheduled sacrifices or deaths. There were no CaHMB-related adverse effects on clinical observations, body weights, food consumption, clinical chemistry, hematology, absolute or relative organ weights, or macroscopic or microscopic observations. A statistically significant increase in inorganic phosphorous was observed in male animals in the 5% feeding group; however, this effect was not considered adverse. Based on the results of this study, the no-observed-adverse-effect level (NOAEL) was considered to be 5% of CaHMB mixed with diet (3.49 g/kg BW for males and 4.16 g/kg BW for females).

Immunogenicity and efficacy against lethal aerosol staphylococcal enterotoxin B challenge in monkeys by intramuscular and respiratory delivery of proteosome-toxoid vaccines

Staphylococcal enterotoxin B (SEB), a primary cause of food poisoning, is also a superantigen that can cause toxic shock after traumatic or surgical staphylococcal wound [correction of would] infections or viral influenza-associated staphylococcal superinfections or when aerosolized for use as a potential biologic warfare threat agent. Intranasal or intramuscular (i.m.) immunization with formalinized SEB toxoid formulated with meningococcal outer membrane protein proteosomes has previously been shown to be immunogenic and protective against lethal respiratory or parenteral SEB challenge in murine models of SEB intoxication. Here, it is demonstrated that immunization of nonhuman primates with the proteosome-SEB toxoid vaccine is safe, immunogenic, and protective against lethal aerosol challenge with 15 50% lethal doses of SEB. Monkeys (10 per group) were primed i.m. and given booster injections by either the i.m. or intratracheal route without adverse side effects. Anamnestic anti-SEB serum immunoglobulin G (IgG) responses were elicited in all monkeys, but strong IgA responses in sera and bronchial secretions were elicited both pre- and post-SEB challenge only in monkeys given booster injections intratracheally. The proteosome-SEB toxoid vaccine was efficacious by both routes in protecting 100% of monkeys against severe symptomatology and death from aerosolized-SEB intoxication. These data confirm the safety, immunogenicity, and efficacy in monkeys of parenteral and respiratory vaccination with the proteosome-SEB toxoid, thereby supporting clinical trials of this vaccine in humans. The safety and enhancement of both bronchial and systemic IgA and IgG responses by the proteosome vaccine delivered by a respiratory route are also encouraging for the development of mucosally delivered proteosome vaccines to protect against SEB and other toxic or infectious respiratory pathogens.

Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study

BACKGROUND

The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity.

METHODS

To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively.

RESULTS

There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10-2.04 and HR 2.16, 95%CI 1.24-3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele.

CONCLUSION

The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers.

KIT-positive Gastrointestinal Stromal Tumor in a 22-year-old Male Chimpanzee (Pan troglodites)

Gastrointestinal stromal tumors (GIST), KIT-positive and KIT signaling driven or platelet-derived growth factor receptor α (PDGFRA) signaling driven mesenchymal tumors, are poorly known in nonhuman primates. Availability of KIT- and PDGFRA-inhibitor drug imatinib mesylate has greatly raised the interest for these tumors. At necropsy of a 22-year-old male chimpanzee, a round, firm 2-cm intramural tumor was incidentally found in the midbody of the stomach and diagnosed as a GIST. Histologically, the mass was composed of spindle to polygonal epithelioid cells arranged in short to intermediate-length, interlacing streams, bundles, and nodular whorls often separated by hyalinized eosinophilic matrix. The mitotic rate was a maximum 1/50 high-power field. Immunohistochemically, the tumor cells were diffusely positive for KIT and CD34, focally positive for α-smooth muscle actin, and negative for muscle specific actin, desmin, S-100 protein, synaptophy-sin, and glial fibrillary acidic protein. Because the majority of human GISTs have gain-of-function KIT or PDGFRA mutations, genomic sequences of KIT exons 9, 11, 13, and 17 and PDGFRA exons 12 and 18 from this chimpanzee GIST were polymerase chain reaction amplified and sequenced. However, no mutation was identified in the analyzed “mutational hot spots.” This study is the first extensive histomorphologic, immunohistochemical, and molecular genetic analysis of a chimpanzee GIST. More cases of nonhuman primate GISTs should be analyzed to discover the clinicopathologic spectrum of GISTs in these species.

Novel sulfonate derivatives: potent antimitotic agents

The synthesis and biological evaluation of novel sulfonate analogues of E-7010 are reported. Several of the compounds are potent inhibitors of cell proliferation and tubulin polymerization. Importantly, these compounds are also active against P-glycoprotein positive (+) cancer cells, which are resistant to many other antitumor agents.

Lactadherin is a candidate oviduct Lewis X trisaccharide receptor on porcine spermatozoa

A recent study has demonstrated that porcine spermatozoa recognize with high affinity carbohydrate structures containing Lewis X motifs. Sperm adhesion to Lewis X is proposed to mediate sperm binding to the oviduct epithelium to form a reservoir. The objective of this study was to identify Lewis X-binding proteins from porcine spermatozoa as candidate receptors for oviduct glycans. To identify low-abundance proteins typically masked by proteins originating from seminal fluid, Lewis X candidate receptors were enriched from cauda epididymal boar spermatozoa. Plasma membrane preparations from cauda epididymal spermatozoa were subjected to RP-HPLC and glycan blotting assays to isolate and detect proteins that bind Lewis X. Following bottom-up LC-MS/MS analysis, among the two bands that bound sulfated Lewis X, ADAM5, which spermatozoa, was confidently identified. ADAM family members have been established as contributors to sperm entry into the oviduct. A second sulfated Lewis X-binding protein identified was the peripheral membrane protein lactadherin (also known as P47, SED1 and MFG-E8 in different species). The interaction between Lewis X and lactadherin was functionally important because competitive inhibition by soluble recombinant lactadherin reduced sperm binding to the oviduct epithelium. Furthermore, far-western blotting demonstrated that purified lactadherin could bind oviduct cells. In summary, these findings reveal that, in addition to the previously reported glycan affinity of accessory gland proteins that adhere to spermatozoa, multiple proteins intrinsic to spermatozoa have affinity for a specific oviduct glycan. Further, in addition to binding to the zona pellucida, lactadherin is now implicated in binding to oviduct glycans to promote formation of the sperm reservoir.

Endothelial nitric oxide synthase (ecNOS) 4 a/b gene polymorphism and carotid artery intima-media thickness in type-1 diabetic patients

AIM

To study putative associations of the ecNOS 4 a/b polymorphism with carotid artery intima-media thickness (IMT) and diabetic complications in young type-1 diabetic patients.

METHODS

Study participants were 147 type-1 diabetic patients (56 men and 91 women), mean age 30.1 +/- 6.6 years (range 14 - 44), with a diabetes duration of 13.1 +/- 8.1 years. HbA1c, albuminuria, and lipid status were assessed by standard laboratory techniques, the ecNOS 4 a/b genotype was determined by polymerase chain reaction with subsequent polyacrylamide gel electrophoresis. The patients were categorized according to the presence or absence of hypertension, nephropathy and retinopathy. The IMT, which can be used to estimate early stages of arteriosclerosis, was measured by high-resolution ultrasonography.

RESULTS

The ecNOS genotypes were distributed as follows: 7.5 % a/a, 30.6 % a/b, and 61.9 % b/b. The IMT values did not differ between the patients with various ecNOS genotypes (a/a: 0.62 +/- 0.13; a/b: 0.63 +/- 0.21; b/b: 0.63 +/- 0.13; all: 0.63 +/- 0.15 mm). The prevalence of retinopathy was significantly higher in patients with the b/b genotype (odds ratio: 2.4 vs. a/a+a/b; 95 % CI, 1.1 - 5.3).

CONCLUSIONS

Our results do not support the hypothesis that the ecNOS 4 a/b polymorphism interacts with the development of early carotid arteriosclerosis in young type-1 diabetic patients, but they give grounds to assume that in these patients it could influence the occurence of diabetic retinopathy.

Evaluation of the insertion/deletion ACE gene polymorphism as a risk factor for carotid artery intima-media thickening and hypertension in young type 1 diabetic patients

OBJECTIVE

To study the distribution of the insertion/deletion polymorphism of the ACE gene in young type 1 diabetic patients and to evaluate possible associations between the ACE genotype, arterial hypertension, and intima-media thickness (IMT) of the common carotid artery.

RESEARCH DESIGN AND METHODS

Study participants were 148 type 1 diabetic patients (56 men and 92 women), aged 14-44 years, with a diabetes duration of > or = 2 years. HbA1c, albuminuria, and lipid status were assessed by standard laboratory techniques; the ACE genotypes were assessed by polymerase chain reaction. The patients were categorized according to the presence or absence of hypertension, nephropathy, and retinopathy. The IMT, which can be used to estimate early stages of atherosclerosis, was measured by high-resolution ultrasonography.

RESULTS

The ACE genotypes were distributed as follows: 21% II, 37% ID, 42% DD. The IMT values did not differ among patients with various ACE genotypes (0.63 +/- 0.15 mm), but the prevalence of hypertension was significantly higher in patients with DD (odds ratio, 4.26 versus II + ID; 95% CI, 1.64-11.06). Multiple linear regression analysis showed that only age, hypertension, and sex were determinants for the IMT.

CONCLUSIONS

Our results suggest a relationship between the prevalence of hypertension and the deletion polymorphism of the ACE gene in young type 1 diabetic patients, but we could not find an association between carotid artery IMT and ACE genotype in this population.

Aorto-coronary vein fistula. A complication of coronary artery bypass graft surgery

We report two cases of the inadvertent insertion of a saphenous vein bypass graft into the anterior cardiac vein creating an aortocoronary vein fistula. The clinical recognition, evaluation, and management are discussed. Suggestions on surgical technique to help minimize or eliminate this potential complication during saphenous vein bypass surgery are proposed.

(1,3) beta-Glucan synthase activity of Neurospora crassa: identification of a substrate-binding protein

(1,3)beta-Glucan synthase activity from the filamentous Ascomycete Neurospora crassa was purified 1300-fold to a specific activity of 14,000 nmol glucose incorporated/min per mg protein. Hyphae were disrupted and crude membrane fractions obtained by high-speed centrifugation. Membrane fractions were extracted with Tergitol NP-40 and a second high-speed particulate fraction was obtained. Enzyme activity was solubilized with (3-((3-cholamidopropyl)dimethylammonio)-1-propanesulfonate and octyl-beta-D-glucoside from Tergitol-extracted membrane preparations. Solubilized enzyme activity was purified by product entrapment and recovered by low-speed centrifugation through a layer of sucrose. SDS-PAGE analysis revealed 2 proteins of 165 and 100 kDa as likely candidates for subunits of the (1,3)beta-glucan synthase enzyme complex. 5-Azido-[32P]UDP-glucose was photo-crosslinked to UDP-glucose-binding proteins in each fraction of the purification procedure. Autoradiograms of SDS-PAGE gels revealed a single protein of 165 kDa enriching with enzyme activity and labeling with the substrate analog. Photoincorporation of 5-azido-[32P]UDP-glucose by the 165 kDa protein was competed by 0.25 mM UDP-glucose (80%) and TDP-glucose (65%) while ADP-glucose (27%), CDP-glucose (36%), and GDP-glucose (8%) where less effective. These results were similar to in vitro inhibition of enzyme activity by the same compounds. These data strongly suggest that the 165 kDa protein is a substrate-binding subunit of (1,3)beta-glucan synthase.